Support tests in freestanding

Summary:
Freestanding is *weird*. The standard allows it to differ in a bunch of odd
manners from regular C++, and the committee would like to improve that
situation. I'd like to make libc++ behave better with what freestanding should
be, so that it can be a tool we use in improving the standard. To do that we
need to try stuff out, both with "freestanding the language mode" and
"freestanding the library subset".

Let's start with the super basic: run the libc++ tests in freestanding, using
clang as the compiler, and see what works. The easiest hack to do this:

In utils/libcxx/test/config.py add:

  self.cxx.compile_flags += ['-ffreestanding']

Run the tests and they all fail.

Why? Because in freestanding `main` isn't special. This "not special" property
has two effects: main doesn't get mangled, and main isn't allowed to omit its
`return` statement. The first means main gets mangled and the linker can't
create a valid executable for us to test. The second means we spew out warnings
(ew) and the compiler doesn't insert the `return` we omitted, and main just
falls of the end and does whatever undefined behavior (if you're luck, ud2
leading to non-zero return code).

Let's start my work with the basics. This patch changes all libc++ tests to
declare `main` as `int main(int, char**` so it mangles consistently (enabling us
to declare another `extern "C"` main for freestanding which calls the mangled
one), and adds `return 0;` to all places where it was missing. This touches 6124
files, and I apologize.

The former was done with The Magic Of Sed.

The later was done with a (not quite correct but decent) clang tool:

  https://gist.github.com/jfbastien/793819ff360baa845483dde81170feed

This works for most tests, though I did have to adjust a few places when e.g.
the test runs with `-x c`, macros are used for main (such as for the filesystem
tests), etc.

Once this is in we can create a freestanding bot which will prevent further
regressions. After that, we can start the real work of supporting C++
freestanding fairly well in libc++.

<rdar://problem/47754795>

Reviewers: ldionne, mclow.lists, EricWF

Subscribers: christof, jkorous, dexonsmith, arphaman, miyuki, libcxx-commits

Differential Revision: https://reviews.llvm.org/D57624

llvm-svn: 353086

1186 files changed, 3547 insertions, 1190 deletions

diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
index 6ea9a8ec8be..961eda3ac8f 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/allocs.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -113,4 +113,6 @@ int main()
              std::scoped_allocator_adaptor<A1<int>>,
              std::scoped_allocator_adaptor<A2<int>>>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
index c1460603486..d3734cae10e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_copy.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<double>> B;
@@ -64,4 +64,6 @@ int main()
         assert(a2 == a1);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
index 99f0e38fc85..427e2995788 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/converting_move.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<double>> B;
@@ -69,4 +69,6 @@ int main()
         assert(A3<int>::move_called == true);
         assert(a2 == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
index 38878e234e9..69b767b909e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/copy.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -64,4 +64,6 @@ int main()
         assert(A3<int>::move_called == false);
         assert(a2 == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
index ac27f8b5465..fdf21cec3e0 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.cnstr/default.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -53,4 +53,6 @@ int main()
         assert(A3<int>::move_called == false);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
index 7b093826a85..6d644db85e8 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.fail.cpp
@@ -21,8 +21,10 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     std::scoped_allocator_adaptor<A1<int>> a;
     a.allocate(10);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
index 057541dd099..05a1649e4a6 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -44,4 +44,6 @@ int main()
         assert(A1<int>::allocate_called == true);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
index ffc59b80041..7cf3d410909 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.fail.cpp
@@ -21,8 +21,10 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     std::scoped_allocator_adaptor<A1<int>> a;
     a.allocate(10, (const void*)0); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
index afe3e40d9f1..db9338d31b8 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/allocate_size_hint.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -65,4 +65,6 @@ int main()
         assert(a.allocate(10, (const void*)20) == (int*)20);
         assert(A2<int>::allocate_called == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
index 6e02326fa4b..97ae33d9157 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct.pass.cpp
@@ -110,7 +110,7 @@ struct F
 
 bool F::constructed = false;
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -184,4 +184,6 @@ int main()
         assert(A3<F>::constructed);
         s->~S();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
index 85fdd38f00d..7aa45f05add 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair.pass.cpp
@@ -135,7 +135,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
index 30fea45b021..d1a03bc05fc 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_const_lvalue_pair.pass.cpp
@@ -151,7 +151,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
index c6e13bc1839..14f413bd867 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_piecewise.pass.cpp
@@ -152,7 +152,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
index 243b9e9979e..c26b4652cc4 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_rvalue.pass.cpp
@@ -151,7 +151,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
index acbe241e7c6..7a4b14956f0 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_pair_values.pass.cpp
@@ -143,7 +143,9 @@ void test_with_inner_alloc()
         std::free(ptr);
     }
 }
-int main() {
+int main(int, char**) {
     test_no_inner_alloc();
     test_with_inner_alloc();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
index 6a65d2ac6a0..e93f37f412e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/construct_type.pass.cpp
@@ -125,8 +125,10 @@ void test_bullet_three() {
     POuter.reset();
 }
 
-int main() {
+int main(int, char**) {
     test_bullet_one();
     test_bullet_two();
     test_bullet_three();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
index e5c17edaf12..425f00ad4f4 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/deallocate.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -42,4 +42,6 @@ int main()
         assert((A1<int>::deallocate_called == std::pair<int*, std::size_t>((int*)10, 20)));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
index 02c7afe4a14..50c9d24f07d 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/destroy.pass.cpp
@@ -31,7 +31,7 @@ struct B
 
 bool B::constructed = false;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<B>> A;
@@ -65,4 +65,6 @@ int main()
         assert(A3<S>::destroy_called);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
index ad0f2e2951f..7e73939f8ee 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/inner_allocator.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -40,4 +40,6 @@ int main()
             std::scoped_allocator_adaptor<A2<int>, A3<int>>(A2<int>(6), A3<int>(8))));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
index 51a9f811786..de9cf4d0cad 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/max_size.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -38,4 +38,6 @@ int main()
         assert(a.max_size() == 200);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
index ccea2b2c0e1..9a90d17c0c6 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/outer_allocator.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -39,4 +39,6 @@ int main()
         A a(A1<int>(5), A2<int>(6), A3<int>(8));
         assert(a.outer_allocator() == A1<int>(5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
index ef42207574f..8253fee5518 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.members/select_on_container_copy_construction.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -50,4 +50,6 @@ int main()
         assert(a2.inner_allocator().inner_allocator().outer_allocator().id() == -1);
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
index 49f242ddf59..10475403d22 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/allocator_pointers.pass.cpp
@@ -109,7 +109,7 @@ void test_void_pointer()
 
 struct Foo { int x; };
 
-int main()
+int main(int, char**)
 {
     test_pointer<std::scoped_allocator_adaptor<std::allocator<char>>> ();
     test_pointer<std::scoped_allocator_adaptor<std::allocator<int>>> ();
@@ -118,7 +118,9 @@ int main()
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<char>>> ();
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<int>>> ();
     test_void_pointer<std::scoped_allocator_adaptor<std::allocator<Foo>>> ();
+
+  return 0;
 }
 #else
-int main() {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
index 05618904428..2aa7a989114 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/inner_allocator_type.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::inner_allocator_type,
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::inner_allocator_type,
         std::scoped_allocator_adaptor<A2<int>, A3<int>>>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
index a549366c9d9..628505f65cd 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/is_always_equal.pass.cpp
@@ -21,7 +21,7 @@
 #include "allocators.h"
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     // sanity checks
     static_assert( (std::is_same<
@@ -68,4 +68,6 @@ int main()
               std::allocator_traits<A2<int>>::is_always_equal::value &&
               std::allocator_traits<A3<int>>::is_always_equal::value)
         ), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
index 6f3605224bf..fea53af299e 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_copy_assignment.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_copy_assignment,
@@ -34,4 +34,6 @@ int main()
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_copy_assignment,
         std::true_type>::value), "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
index 5c207c930c4..d04ea6f1a43 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_move_assignment.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_move_assignment,
@@ -34,4 +34,6 @@ int main()
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_move_assignment,
         std::true_type>::value), "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
index 5b70dd8fb92..fcec67879fc 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/allocator.adaptor.types/propagate_on_container_swap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>>::propagate_on_container_swap,
@@ -33,4 +33,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A1<int>, A2<int>, A3<int>>::propagate_on_container_swap,
         std::true_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
index 0f3813e1ab9..1f871876f13 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/copy_assign.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -68,4 +68,6 @@ int main()
         assert(A3<int>::move_called == false);
         assert(aN == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
index 22987adefe7..aaf5c1d59ad 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/eq.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -58,4 +58,6 @@ int main()
         assert(a2 != a1);
         assert(!(a2 == a1));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
index 0342f614c98..c17c6d38439 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/scoped.adaptor.operators/move_assign.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::scoped_allocator_adaptor<A1<int>> A;
@@ -68,4 +68,6 @@ int main()
         assert(A3<int>::move_called == true);
         assert(aN == a1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp b/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
index 00a007f06ea..7820e29eef2 100644
--- a/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
+++ b/libcxx/test/std/utilities/allocator.adaptor/types.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "allocators.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<
         A1<int>,
@@ -96,4 +96,6 @@ int main()
     static_assert((std::is_same<
         std::scoped_allocator_adaptor<A2<int>, A1<int>>::const_void_pointer,
         const void*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
index 0a8c3f7814b..6cf1efb86b3 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/copy.pass.cpp
@@ -191,7 +191,7 @@ void test_copy_assign_throws()
 #endif
 }
 
-int main() {
+int main(int, char**) {
     test_copy_assign<small1, small2>();
     test_copy_assign<large1, large2>();
     test_copy_assign<small, large>();
@@ -201,4 +201,6 @@ int main() {
     test_copy_assign_self();
     test_copy_assign_throws<small_throws_on_copy>();
     test_copy_assign_throws<large_throws_on_copy>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
index 4baadb2bbad..6e1b6d6a6f4 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/move.pass.cpp
@@ -104,7 +104,7 @@ void test_move_assign_noexcept() {
       );
 }
 
-int main() {
+int main(int, char**) {
     test_move_assign_noexcept();
     test_move_assign<small1, small2>();
     test_move_assign<large1, large2>();
@@ -112,4 +112,6 @@ int main() {
     test_move_assign<large, small>();
     test_move_assign_empty<small>();
     test_move_assign_empty<large>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
index 7ccec4b3f88..888a6a654b3 100644
--- a/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.assign/value.pass.cpp
@@ -202,7 +202,7 @@ void test_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_assign_value<small1, small2>();
     test_assign_value<large1, large2>();
     test_assign_value<small, large>();
@@ -213,4 +213,6 @@ int main() {
     test_assign_throws<large_throws_on_copy>();
     test_assign_throws<throws_on_move, /* Move = */ true>();
     test_sfinae_constraints();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
index 6c4e9576d44..318d9ecabba 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/copy.pass.cpp
@@ -98,10 +98,12 @@ void test_copy()
     assert(Type::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_copy<small>();
     test_copy<large>();
     test_copy_empty();
     test_copy_throws<small_throws_on_copy>();
     test_copy_throws<large_throws_on_copy>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
index 12692a17113..6cd7b8937d2 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/default.pass.cpp
@@ -20,7 +20,7 @@
 #include "any_helpers.h"
 #include "count_new.hpp"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     {
@@ -43,4 +43,6 @@ int main()
         any const a;
         assertEmpty(a);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
index f696ac5a206..9684fcac7e2 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/in_place_type.pass.cpp
@@ -187,7 +187,7 @@ void test_constructor_explicit() {
     static_assert(std::is_constructible<std::any, IT, std::initializer_list<int>&, int>::value, "");
 }
 
-int main() {
+int main(int, char**) {
     test_in_place_type<small>();
     test_in_place_type<large>();
     test_in_place_type<small_throws_on_copy>();
@@ -198,4 +198,6 @@ int main() {
     test_in_place_type_decayed();
     test_ctor_sfinae();
     test_constructor_explicit();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
index 265972a01e9..e75d56ef290 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/move.pass.cpp
@@ -95,7 +95,7 @@ void test_move() {
     assert(Type::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     // noexcept test
     {
@@ -108,4 +108,6 @@ int main()
     test_move<large>();
     test_move_empty();
     test_move_does_not_throw();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
index c80a407ff06..ed588497514 100644
--- a/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.cons/value.pass.cpp
@@ -151,11 +151,13 @@ void test_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_copy_move_value<small>();
     test_copy_move_value<large>();
     test_copy_value_throws<small_throws_on_copy>();
     test_copy_value_throws<large_throws_on_copy>();
     test_move_value_throws();
     test_sfinae_constraints();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
index 3ac003dd086..7cb5d491328 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/emplace.pass.cpp
@@ -275,7 +275,7 @@ void test_emplace_sfinae_constraints() {
     }
 }
 
-int main() {
+int main(int, char**) {
     test_emplace_type<small>();
     test_emplace_type<large>();
     test_emplace_type<small_throws_on_copy>();
@@ -288,4 +288,6 @@ int main() {
     test_emplace_throws<SmallThrows>();
     test_emplace_throws<LargeThrows>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
index 352b25b8010..0a01e86252c 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/reset.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     using std::any_cast;
@@ -67,4 +67,6 @@ int main()
         assertEmpty<large>(a);
         assert(large::count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
index f1ff60d478b..f4f5ee4969c 100644
--- a/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.modifiers/swap.pass.cpp
@@ -127,7 +127,7 @@ void test_self_swap() {
     assert(large::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_noexcept();
     test_swap_empty<small>();
@@ -137,4 +137,6 @@ int main()
     test_swap<small, large>();
     test_swap<large, small>();
     test_self_swap();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
index 9b747dca610..54b4153c974 100644
--- a/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.observers/has_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     // noexcept test
@@ -60,4 +60,6 @@ int main()
         a = l;
         assert(a.has_value());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp b/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
index 8d3b4081405..bb9089cd83e 100644
--- a/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/any.observers/type.pass.cpp
@@ -18,7 +18,7 @@
 #include <cassert>
 #include "any_helpers.h"
 
-int main()
+int main(int, char**)
 {
     using std::any;
     {
@@ -37,4 +37,6 @@ int main()
         any const a(l);
         assert(a.type() == typeid(large));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp b/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
index b757f7b0bbe..3a275d51e4a 100644
--- a/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.class/not_literal_type.pass.cpp
@@ -15,6 +15,8 @@
 #include <any>
 #include <type_traits>
 
-int main () {
+int main(int, char**) {
     static_assert(!std::is_literal_type<std::any>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
index 8de9164c31f..9b9ec410958 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_pointer.pass.cpp
@@ -166,7 +166,7 @@ void test_cast_function_pointer() {
     assert(fn_ptr == test_fn);
 }
 
-int main() {
+int main(int, char**) {
     test_cast_is_noexcept();
     test_cast_return_type();
     test_cast_nullptr();
@@ -175,4 +175,6 @@ int main() {
     test_cast<large>();
     test_cast_non_copyable_type();
     test_cast_function_pointer();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
index 810c482df78..fb69f0d39fb 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_reference.pass.cpp
@@ -309,7 +309,7 @@ void test_cast_to_value() {
     assert(Type::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_cast_is_not_noexcept();
     test_cast_return_type();
     test_cast_empty();
@@ -317,4 +317,6 @@ int main() {
     test_cast_to_reference<large>();
     test_cast_to_value<small>();
     test_cast_to_value<large>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
index cd69a3d8508..396d994d22d 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/any_cast_request_invalid_value_category.fail.cpp
@@ -61,9 +61,11 @@ void test_rvalue_any_cast_request_lvalue()
     any_cast<int&>(42);
 }
 
-int main()
+int main(int, char**)
 {
     test_const_lvalue_cast_request_non_const_lvalue();
     test_lvalue_any_cast_request_rvalue();
     test_rvalue_any_cast_request_lvalue();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
index c0c6e03fdcf..8669de4fddb 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/const_correctness.fail.cpp
@@ -24,7 +24,7 @@ struct TestType2 {};
 // is triggered by these tests.
 // expected-error@const_correctness.fail.cpp:* 0+ {{call to unavailable function 'any_cast': introduced in macOS 10.14}}
 
-int main()
+int main(int, char**)
 {
     using std::any;
     using std::any_cast;
@@ -46,4 +46,6 @@ int main()
     // expected-error@any:* {{cannot cast from lvalue of type 'const TestType2' to rvalue reference type 'TestType2 &&'; types are not compatible}}
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be a const lvalue reference or a CopyConstructible type"}}
     any_cast<TestType2 &&>(static_cast<any const&&>(a)); // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
index c90df2ebd37..97f1d9795bc 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/not_copy_constructible.fail.cpp
@@ -43,7 +43,7 @@ struct no_move {
 // is triggered by these tests.
 // expected-error@not_copy_constructible.fail.cpp:* 0+ {{call to unavailable function 'any_cast': introduced in macOS 10.14}}
 
-int main() {
+int main(int, char**) {
     any a;
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be an lvalue reference or a CopyConstructible type"}}
     // expected-error@any:* {{static_cast from 'no_copy' to 'no_copy' uses deleted function}}
@@ -58,4 +58,6 @@ int main() {
     // expected-error-re@any:* {{static_assert failed{{.*}} "ValueType is required to be an rvalue reference or a CopyConstructible type"}}
     // expected-error@any:* {{static_cast from 'typename remove_reference<no_move &>::type' (aka 'no_move') to 'no_move' uses deleted function}}
     any_cast<no_move>(static_cast<any &&>(a));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
index 19453582479..1ce06e289a9 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/any.cast/reference_types.fail.cpp
@@ -21,7 +21,7 @@
 using std::any;
 using std::any_cast;
 
-int main()
+int main(int, char**)
 {
     any a(1);
 
@@ -50,4 +50,6 @@ int main()
 
     // expected-error-re@any:* 1 {{static_assert failed{{.*}} "_ValueType may not be a reference."}}
     any_cast<int const &&>(&a2); // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
index e185f239f69..1e9708545ff 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/make_any.pass.cpp
@@ -131,7 +131,7 @@ void test_make_any_throws()
 
 #endif
 
-int main() {
+int main(int, char**) {
     test_make_any_type<small>();
     test_make_any_type<large>();
     test_make_any_type<small_throws_on_copy>();
@@ -144,4 +144,6 @@ int main() {
     test_make_any_throws<LargeThrows>();
 
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp b/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
index 3e5a91d0d23..cff34964a84 100644
--- a/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/any/any.nonmembers/swap.pass.cpp
@@ -28,7 +28,7 @@
 using std::any;
 using std::any_cast;
 
-int main()
+int main(int, char**)
 {
 
     { // test noexcept
@@ -44,4 +44,6 @@ int main()
         assert(any_cast<int>(a1) == 2);
         assert(any_cast<int>(a2) == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
index 35ddfa32e88..2e744cc8187 100644
--- a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.bool.fail.cpp
@@ -18,7 +18,7 @@
 
 #include <charconv>
 
-int main()
+int main(int, char**)
 {
     using std::from_chars;
     char buf[] = "01001";
@@ -26,4 +26,6 @@ int main()
 
     from_chars(buf, buf + sizeof(buf), lv);      // expected-error {{call to deleted function}}
     from_chars(buf, buf + sizeof(buf), lv, 16);  // expected-error {{call to deleted function}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
index 9f05250d356..d750cb4a89c 100644
--- a/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp
@@ -183,8 +183,10 @@ struct test_signed : roundtrip_test_base<T>
     }
 };
 
-int main()
+int main(int, char**)
 {
     run<test_basics>(integrals);
     run<test_signed>(all_signed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
index 36c7d3ccadb..5c947d122f4 100644
--- a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.bool.fail.cpp
@@ -18,7 +18,7 @@
 
 #include <charconv>
 
-int main()
+int main(int, char**)
 {
     using std::to_chars;
     char buf[10];
@@ -26,4 +26,6 @@ int main()
 
     to_chars(buf, buf + sizeof(buf), false);   // expected-error {{call to deleted function}}
     to_chars(buf, buf + sizeof(buf), lv, 16);  // expected-error {{call to deleted function}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
index 18ddf203b3e..c034151de8a 100644
--- a/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
+++ b/libcxx/test/std/utilities/charconv/charconv.to.chars/integral.pass.cpp
@@ -81,8 +81,10 @@ struct test_signed : to_chars_test_base<T>
     }
 };
 
-int main()
+int main(int, char**)
 {
     run<test_basics>(integrals);
     run<test_signed>(all_signed);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
index c191b191bcd..1dbbd8533c7 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/divides.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::divides<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::divides<> () (3.0, 2);
     static_assert ( bar == 1.5, "" ); // exact in binary
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
index 54ab577ea43..186695f7b93 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/minus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::minus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::minus<> () (3.0, 2);
     static_assert ( bar == 1.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
index f426c57cfee..3679a2d3251 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/modulus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::modulus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr int bar = std::modulus<> () (3L, 2);
     static_assert ( bar == 1, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
index 5ef4791b59e..a09e59c784c 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/multiplies.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::multiplies<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::multiplies<> () (3.0, 2);
     static_assert ( bar == 6.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
index d7346c769f7..553bf83e2d4 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/negate.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::negate<int> F;
     const F f = F();
@@ -36,4 +36,6 @@ int main()
     constexpr double bar = std::negate<> () (3.0);
     static_assert ( bar == -3.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
index 6bca266e078..b2614f4304d 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/plus.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::plus<int> F;
     const F f = F();
@@ -37,4 +37,6 @@ int main()
     constexpr double bar = std::plus<> () (3.0, 2);
     static_assert ( bar == 5.0, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
index ca57c223a2a..154a0f8877a 100644
--- a/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/arithmetic.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::plus<int>>::value, "" );
     static_assert ( !is_transparent<std::plus<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
index 4c025d1415a..931778f54d9 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/PR23141_invoke_not_constexpr.pass.cpp
@@ -28,7 +28,9 @@ struct Fun
   }
 };
 
-int main()
+int main(int, char**)
 {
     std::bind(Fun{}, std::placeholders::_1, 42)("hello");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
index fc089e16528..7010b33f331 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/bind_return_type.pass.cpp
@@ -115,7 +115,7 @@ void do_test_r(Fn* func) {
     }
 }
 
-int main()
+int main(int, char**)
 {
     do_test<int>(return_value);
     do_test<int&>(return_lvalue);
@@ -129,4 +129,6 @@ int main()
     do_test_r<long>(return_rvalue);
     do_test_r<long>(return_const_rvalue);
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
index ccc6c27e716..8beeb3321d5 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/copy.pass.cpp
@@ -26,11 +26,13 @@ float _pow(float a, float b)
     return std::pow(a, b);
 }
 
-int main()
+int main(int, char**)
 {
     std::function<float(float, float)> fnc = _pow;
     auto task = std::bind(fnc, 2.f, 4.f);
     auto task2(task);
     assert(task() == 16);
     assert(task2() == 16);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
index b386b99a90f..b87918da110 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
@@ -38,7 +38,7 @@ struct BadUnaryFunction
     }
 };
 
-int main()
+int main(int, char**)
 {
     // Check that BadUnaryFunction::operator()(S const &) is not
     // instantiated when checking if BadUnaryFunction is a nested bind
@@ -47,4 +47,6 @@ int main()
     b(0);
     auto b2 = std::bind<long>(DummyUnaryFunction(), BadUnaryFunction());
     b2(0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
index 8d6bc70e79a..a77e1895d6f 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_int_0.pass.cpp
@@ -40,7 +40,7 @@ struct A_int_0
     int operator()() const {return 5;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::bind(f), 1);
     test(std::bind(&f), 1);
@@ -51,4 +51,6 @@ int main()
     test(std::bind<int>(&f), 1);
     test(std::bind<int>(A_int_0()), 4);
     test_const(std::bind<int>(A_int_0()), 5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
index 92f65af2c91..9b81d330132 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_lvalue.pass.cpp
@@ -280,10 +280,12 @@ test3()
     assert(b);
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     test3();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
index b7facb38ac6..10d2ce017f8 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_rvalue.pass.cpp
@@ -258,10 +258,12 @@ void test_nested()
     assert(std::bind(f_nested, std::bind(g_nested, _1))(3) == 31);
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     test_nested();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
index cc982d1b80f..2c8e56f034e 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_void_0.pass.cpp
@@ -54,7 +54,7 @@ struct A_int_0
     int operator()() const {count += 2; return 5;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::bind(f));
     test(std::bind(&f));
@@ -70,4 +70,6 @@ int main()
     test(std::bind<void>(&g));
     test(std::bind<void>(A_int_0()));
     test_const(std::bind<void>(A_int_0()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
index c4d82948e37..0d5be341353 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/nested.pass.cpp
@@ -41,11 +41,13 @@ struct plus_one
   }
 };
 
-int main()
+int main(int, char**)
 {
     using std::placeholders::_1;
 
     auto g = std::bind(power(), 2, _1);
     assert(g(5) == 32);
     assert(std::bind(plus_one(), g)(5) == 33);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
index cf065e4e382..8314dbe1e8e 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression.pass.cpp
@@ -27,11 +27,13 @@ test(const T&)
 
 struct C {};
 
-int main()
+int main(int, char**)
 {
     test<true>(std::bind(C()));
     test<true>(std::bind(C(), std::placeholders::_2));
     test<true>(std::bind<int>(C()));
     test<false>(1);
     test<false>(std::placeholders::_2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
index da7880fb25f..c1af159b293 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_bind_expression_03.pass.cpp
@@ -24,7 +24,7 @@ void test() {
 
 struct C {};
 
-int main() {
+int main(int, char**) {
     test<int>();
     test<void>();
     test<C>();
@@ -35,4 +35,6 @@ int main() {
     test<int(*)()>();
     test<int (C::*)()>();
     test<decltype(std::placeholders::_2)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
index ecaa45bba28..d2ccf1fafdc 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.isbind/is_placeholder.pass.cpp
@@ -25,7 +25,7 @@ test(const T&)
 
 struct C {};
 
-int main()
+int main(int, char**)
 {
     test<1>(std::placeholders::_1);
     test<2>(std::placeholders::_2);
@@ -41,4 +41,6 @@ int main()
     test<0>(5.5);
     test<0>('a');
     test<0>(C());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
index 8e4ec60ef13..b71aae818a0 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/func.bind.place/placeholders.pass.cpp
@@ -80,7 +80,7 @@ void use_placeholders_to_prevent_unused_warning() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     use_placeholders_to_prevent_unused_warning();
     test(std::placeholders::_1);
@@ -93,4 +93,6 @@ int main()
     test(std::placeholders::_8);
     test(std::placeholders::_9);
     test(std::placeholders::_10);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/func.bind/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bind/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
index 664e3f25dd6..aa532462145 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_and.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_and<int> F;
     const F f = F();
@@ -57,4 +57,6 @@ int main()
     constexpr int bar = std::bit_and<> () (0x58D3L, 0xEA95);
     static_assert ( bar == 0x4891, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
index e18139bc607..8bfa48f3e70 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_not.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_not<int> F;
     const F f = F();
@@ -42,4 +42,6 @@ int main()
 
     constexpr int bar = std::bit_not<> () (0xEA95) & 0xFFFF;
     static_assert ( bar == 0x156A, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
index 19bd1a731c8..8abcd63afaa 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_or.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::bit_or<int> F;
     const F f = F();
@@ -57,4 +57,6 @@ int main()
     constexpr int bar = std::bit_or<> () (0x58D3L, 0xEA95);
     static_assert ( bar == 0xFAD7, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
index 757417a2cb5..070bd4c5f7b 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/bit_xor.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::bit_xor<int> F;
@@ -61,4 +61,6 @@ int main()
     static_assert ( bar == 0xB246, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
index c360a51b4e9..5ad0f233f19 100644
--- a/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/bitwise.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main () {
+int main(int, char**) {
     static_assert ( !is_transparent<std::bit_and<int>>::value, "" );
     static_assert ( !is_transparent<std::bit_and<std::string>>::value, "" );
     static_assert (  is_transparent<std::bit_and<void>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
index 7632dc58061..a0c41432ec4 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/constexpr_init.pass.cpp
@@ -42,6 +42,8 @@ static_assert(test_constexpr_context<int>(), "");
 static_assert(test_constexpr_context<void>(), "");
 
 
-int main() {
+int main(int, char**) {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
index 7ec8f66328d..beed574f89e 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/equal_to.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::equal_to<int> F;
     const F f = F();
@@ -39,4 +39,6 @@ int main()
     constexpr bool bar = std::equal_to<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
index 12111ef28e3..35c05757c8c 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/greater.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::greater<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::greater<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
index 1ac67eadc38..9a6d36c4176 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/greater_equal.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::greater_equal<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::greater_equal<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
index abfe09ad58d..31a2f975b18 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/less.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::less<int> F;
     const F f = F();
@@ -48,4 +48,6 @@ int main()
     constexpr bool bar = std::less<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
index 2e733042409..31cbed17172 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/less_equal.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "pointer_comparison_test_helper.hpp"
 
-int main()
+int main(int, char**)
 {
     typedef std::less_equal<int> F;
     const F f = F();
@@ -49,4 +49,6 @@ int main()
     constexpr bool bar = std::less_equal<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
index fd329157058..0e405de1be9 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/not_equal_to.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::not_equal_to<int> F;
     const F f = F();
@@ -41,4 +41,6 @@ int main()
     constexpr bool bar = std::not_equal_to<> () (36.0, 36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
index f3896770ec0..4be81925b7f 100644
--- a/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/comparisons/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::less<int>>::value, "" );
     static_assert ( !is_transparent<std::less<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.def/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
index b0a41447e05..57350f16c40 100644
--- a/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.invoke/invoke.pass.cpp
@@ -340,9 +340,11 @@ void noexcept_test() {
     }
 }
 
-int main() {
+int main(int, char**) {
     bullet_one_two_tests();
     bullet_three_four_tests();
     bullet_five_tests();
     noexcept_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp b/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
index f7f63a0bd8b..b0404659d78 100644
--- a/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.invoke/invoke_feature_test_macro.pass.cpp
@@ -31,8 +31,10 @@
 
 int foo(int) { return 42; }
 
-int main() {
+int main(int, char**) {
 #if defined(__cpp_lib_invoke)
   assert(std::invoke(foo, 101) == 42);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
index 483f7a327c3..130644fbd29 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.fail.cpp
@@ -35,7 +35,9 @@ test(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::mem_fn(&A::data_));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
index 75211ba21e0..52581881a5b 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_data.pass.cpp
@@ -36,7 +36,9 @@ test(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::mem_fn(&A::data_));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
index a04e49efa20..a271c067008 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function.pass.cpp
@@ -65,7 +65,7 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
@@ -73,4 +73,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((noexcept(std::mem_fn(&A::test0))), ""); // LWG#2489
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
index 9ea6531a2ec..dc93196cdc3 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
index 9258c0a03f4..594e1de8ad6 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_const_volatile.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
index c22baecd9b8..04439387dfe 100644
--- a/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.memfn/member_function_volatile.pass.cpp
@@ -69,9 +69,11 @@ test2(F f)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test0(std::mem_fn(&A::test0));
     test1(std::mem_fn(&A::test1));
     test2(std::mem_fn(&A::test2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp b/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
index c3adbf7ffc5..a1c77841247 100644
--- a/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.not_fn/not_fn.pass.cpp
@@ -602,7 +602,7 @@ void test_lwg2767() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     constructor_tests();
     return_type_tests();
@@ -612,4 +612,6 @@ int main()
     call_operator_forwarding_test();
     call_operator_noexcept_test();
     test_lwg2767();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
index 2bb9cb58371..00b7d53be3a 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/INVOKE_tested_elsewhere.pass.cpp
@@ -12,4 +12,6 @@
 // since they require calling the implementation specific "__invoke" and
 // "__invoke_constexpr" functions.
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
index 76ba44fc994..79a4855ea02 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/binary_function.pass.cpp
@@ -15,10 +15,12 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::binary_function<int, short, bool> bf;
     static_assert((std::is_same<bf::first_argument_type, int>::value), "");
     static_assert((std::is_same<bf::second_argument_type, short>::value), "");
     static_assert((std::is_same<bf::result_type, bool>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
index 0d178b0dc6d..f68b4b37c73 100644
--- a/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.require/unary_function.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::unary_function<int, bool> uf;
     static_assert((std::is_same<uf::argument_type, int>::value), "");
     static_assert((std::is_same<uf::result_type, bool>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
index 3293a3215ed..55cde8fe777 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/default.pass.cpp
@@ -122,7 +122,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
index d0ce11b08bb..106b0d37f61 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pass.cpp
@@ -118,7 +118,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
index 59178deb613..be4db4e5a54 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/hash.pred.pass.cpp
@@ -136,7 +136,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
index 7f3e837a70e..3656caa8749 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bm/pred.pass.cpp
@@ -127,7 +127,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
index 04adb178bf1..0b345deedc1 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/default.pass.cpp
@@ -122,7 +122,9 @@ test2()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
index dca69117583..4106c5d6ae7 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pass.cpp
@@ -117,7 +117,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
index 6a5c215a7fd..757bcc75792 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/hash.pred.pass.cpp
@@ -130,7 +130,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
index 27c3d0c82c2..3a20b88512f 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.bmh/pred.pass.cpp
@@ -124,7 +124,9 @@ test2()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
     test2<random_access_iterator<const char*>, random_access_iterator<const char*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
index 098b8ac113d..eaf5eeb8273 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pass.cpp
@@ -82,7 +82,7 @@ test()
     do_search(Iter1(ij), Iter1(ij+sj), Iter2(ik), Iter2(ik+sk), Iter1(ij+6));
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -92,4 +92,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
index 4b0f016d712..773336f6626 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/func.search.default/default.pred.pass.cpp
@@ -89,7 +89,7 @@ test()
     do_search(Iter1(ih), Iter1(ih+sh), Iter2(ii), Iter2(ii+3), Iter1(ih+3),  sh*3);
 }
 
-int main() {
+int main(int, char**) {
     test<forward_iterator<const int*>, forward_iterator<const int*> >();
     test<forward_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<forward_iterator<const int*>, random_access_iterator<const int*> >();
@@ -99,4 +99,6 @@ int main() {
     test<random_access_iterator<const int*>, forward_iterator<const int*> >();
     test<random_access_iterator<const int*>, bidirectional_iterator<const int*> >();
     test<random_access_iterator<const int*>, random_access_iterator<const int*> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
index 02fe32ece48..779762e7e99 100644
--- a/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.search/nothing_to_do.pass.cpp
@@ -7,6 +7,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
index 2ec1d53c56e..eb223b88e49 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/bad_function_call.pass.cpp
@@ -19,7 +19,9 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_function_call>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
index 6b6ee8a64a7..385919227e0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.badcall/func.wrap.badcall.const/bad_function_call_ctor.pass.cpp
@@ -13,7 +13,9 @@
 #include <functional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::bad_function_call ex;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
index 50fb4f19d5b..2a34eff92e2 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.fail.cpp
@@ -18,7 +18,9 @@
 
 struct S : public std::function<void()> { using function::function; };
 
-int main() {
+int main(int, char**) {
    S f1( [](){} );
    S f2(std::allocator_arg, std::allocator<int>{}, f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
index 8c50c284b42..70f68d2f49b 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/derive_from.pass.cpp
@@ -20,10 +20,12 @@
 using Fn = std::function<void()>;
 struct S : public std::function<void()> { using function::function; };
 
-int main() {
+int main(int, char**) {
     S s( [](){} );
     S f1( s );
 #if TEST_STD_VER <= 14
     S f2(std::allocator_arg, std::allocator<int>{}, s);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
index b6dbcab5301..ec25bdf7802 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.alg/swap.pass.cpp
@@ -57,7 +57,7 @@ int A::count = 0;
 int g(int) {return 0;}
 int h(int) {return 1;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -132,4 +132,6 @@ int main()
     }
     assert(A::count == 0);
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
index 1b55baa02e1..ab5eef37270 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.cap/operator_bool.pass.cpp
@@ -17,7 +17,7 @@
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f;
@@ -25,4 +25,6 @@ int main()
     f = g;
     assert(f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
index c32baebb51d..fe5d24806b7 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F.pass.cpp
@@ -60,7 +60,7 @@ struct LValueCallable {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -111,4 +111,6 @@ int main()
         static_assert(!std::is_constructible<Fn, RValueCallable>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
index abff663cb72..f70a2087cc2 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_assign.pass.cpp
@@ -63,7 +63,7 @@ struct LValueCallable {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -115,4 +115,6 @@ int main()
         static_assert(!std::is_assignable<Fn&, RValueCallable>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
index 1598486661c..21c2f216efe 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_incomplete.pass.cpp
@@ -58,6 +58,8 @@ void test_pr34298()
   }
 }
 
-int main() {
+int main(int, char**) {
   test_pr34298();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
index 89b7876235e..ebea3d0aa95 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/F_nullptr.pass.cpp
@@ -239,8 +239,10 @@ void test_md() {
     test_imp<int MemData::*, int(MemData&)>();
 }
 
-int main() {
+int main(int, char**) {
     test_func();
     test_mf();
     test_md();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
index acbeb9f9c98..50a11fb8198 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.fail.cpp
@@ -18,7 +18,9 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, std::allocator<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
index b048109e54b..3b37ce6ffdc 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc.pass.cpp
@@ -20,10 +20,12 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f(std::allocator_arg, bare_allocator<int>());
     assert(!f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
index bddc9278719..c31c0a21f32 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.fail.cpp
@@ -22,7 +22,9 @@
 
 void foo(int) {}
 
-int main()
+int main(int, char**)
 {
     std::function<void(int)> f(std::allocator_arg, std::allocator<int>(), foo);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
index 4d49434f317..6fa0d6faeaf 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_F.pass.cpp
@@ -106,7 +106,7 @@ void test_for_alloc(Alloc& alloc) {
     test_MemFunClass<int(MemFunClass::*)(int, int) const, int(MemFunClass&, int, int)>(alloc);
 }
 
-int main()
+int main(int, char**)
 {
     {
         bare_allocator<DummyClass> bare_alloc;
@@ -126,4 +126,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
index b6703c0b7b9..621588f8156 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.fail.cpp
@@ -21,9 +21,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::function<void(int)> F;
     F f1;
     F f2(std::allocator_arg, std::allocator<int>(), f1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
index 39050e6f153..583ca162ebf 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_function.pass.cpp
@@ -111,7 +111,7 @@ void test_for_alloc(Alloc& alloc)
     test_MemFunClass<int(MemFunClass::*)(int, int) const, int(MemFunClass&, int, int)>(alloc);
 }
 
-int main()
+int main(int, char**)
 {
   {
     bare_allocator<DummyClass> alloc;
@@ -121,4 +121,6 @@ int main()
     non_default_test_allocator<DummyClass> alloc(42);
     test_for_alloc(alloc);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
index 32d19ebf704..52bc528fe59 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.fail.cpp
@@ -20,7 +20,9 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, std::allocator<int>(), nullptr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
index 6378a6cd9d3..653057f6ec9 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_nullptr.pass.cpp
@@ -20,8 +20,10 @@
 
 #include "min_allocator.h"
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(std::allocator_arg, bare_allocator<int>(), nullptr);
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
index 558b7814ced..643cad8f074 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.fail.cpp
@@ -50,10 +50,12 @@ int A::count = 0;
 
 int g(int) { return 0; }
 
-int main()
+int main(int, char**)
 {
     {
         std::function<int(int)> f = A();
         std::function<int(int)> f2(std::allocator_arg, std::allocator<A>(), std::move(f));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
index 8f379e30305..064046d0b2d 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/alloc_rfunction.pass.cpp
@@ -54,7 +54,7 @@ int A::count = 0;
 
 int g(int) { return 0; }
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -105,4 +105,6 @@ int main()
         assert(f2.target<Ptr>());
         assert(f.target<Ptr>()); // f is unchanged because the target is small
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
index df2a43aba9d..d7b11ae1bfd 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_assign.pass.cpp
@@ -48,7 +48,7 @@ int g(int) { return 0; }
 int g2(int, int) { return 2; }
 int g3(int, int, int) { return 3; }
 
-int main() {
+int main(int, char**) {
   assert(globalMemCounter.checkOutstandingNewEq(0));
   {
     std::function<int(int)> f = A();
@@ -134,4 +134,6 @@ int main() {
     assert(f.target<int (*)(int)>() == 0);
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
index 9f03ee7a1f9..dbbde5ce473 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/copy_move.pass.cpp
@@ -50,7 +50,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -161,4 +161,6 @@ int main()
         LIBCPP_ASSERT(f.target<Ptr>()); // f is unchanged because the target is small
     }
 #endif  // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
index 06ea4e058d0..46c14ce368b 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/default.pass.cpp
@@ -15,8 +15,10 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f;
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
index 026cfc2d484..e15fbbaae54 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/move_reentrant.pass.cpp
@@ -33,7 +33,7 @@ struct A
 std::function<void()> A::global;
 bool A::cancel = false;
 
-int main()
+int main(int, char**)
 {
   A::global = A();
   assert(A::global.target<A>());
@@ -42,4 +42,6 @@ int main()
   A::cancel = true;
   A::global = std::function<void()>(nullptr);
   assert(!A::global.target<A>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
index b685d53bfa0..d58e191c470 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t.pass.cpp
@@ -15,8 +15,10 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::function<int(int)> f(nullptr);
     assert(!f);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
index 7a8d3e380e2..ff81080ffda 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign.pass.cpp
@@ -46,7 +46,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     assert(globalMemCounter.checkOutstandingNewEq(0));
     {
@@ -68,4 +68,6 @@ int main()
     assert(globalMemCounter.checkOutstandingNewEq(0));
     assert(f.target<int(*)(int)>() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
index c4006a7c9fd..def86085ddb 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.con/nullptr_t_assign_reentrant.pass.cpp
@@ -33,7 +33,7 @@ struct A
 std::function<void()> A::global;
 bool A::cancel = false;
 
-int main()
+int main(int, char**)
 {
   A::global = A();
   assert(A::global.target<A>());
@@ -42,4 +42,6 @@ int main()
   A::cancel = true;
   A::global = nullptr;
   assert(!A::global.target<A>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
index 5f91e5c87d9..0f8e051d406 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.fail.cpp
@@ -39,7 +39,9 @@ test_int_1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_int_1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
index 7775cad6773..fb67a3abf4a 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.inv/invoke.pass.cpp
@@ -401,7 +401,7 @@ void test_int_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_0();
     test_int_0();
@@ -409,4 +409,6 @@ int main()
     test_int_1();
     test_void_2();
     test_int_2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
index 5a6f503a284..8ddd1cd2b18 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/assign_F_alloc.pass.cpp
@@ -48,7 +48,7 @@ public:
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER <= 14
     {
@@ -60,4 +60,6 @@ int main()
     }
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
index a75aee33048..93997a0b55f 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.mod/swap.pass.cpp
@@ -57,7 +57,7 @@ int h(int) { return 1; }
 int g2(int, int) { return 2; }
 int g3(int, int, int) { return 3; }
 
-int main() {
+int main(int, char**) {
   assert(globalMemCounter.checkOutstandingNewEq(0));
   {
     std::function<int(int)> f1 = A(1);
@@ -189,4 +189,6 @@ int main() {
   }
   assert(globalMemCounter.checkOutstandingNewEq(0));
   assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
index c68a1ca8262..698a461c8f0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.nullptr/operator_==.pass.cpp
@@ -27,7 +27,7 @@
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f;
@@ -37,4 +37,6 @@ int main()
     assert(f != nullptr);
     assert(nullptr != f);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
index 7b59b56d092..d5031ba06e7 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target.pass.cpp
@@ -55,7 +55,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f = A();
@@ -89,4 +89,6 @@ int main()
     assert(f.target<int>() == nullptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
index 52d07a45a50..d9c8fc48d75 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/func.wrap.func.targ/target_type.pass.cpp
@@ -47,7 +47,7 @@ int A::count = 0;
 
 int g(int) {return 0;}
 
-int main()
+int main(int, char**)
 {
     {
     std::function<int(int)> f = A();
@@ -57,4 +57,6 @@ int main()
     std::function<int(int)> f;
     assert(f.target_type() == typeid(void));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
index 496dee8ae75..8083ad83ac0 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/func.wrap.func/types.pass.cpp
@@ -98,10 +98,12 @@ void test_other_function ()
     static_assert((!has_second_argument_type<F>::value), "" );
 }
 
-int main()
+int main(int, char**)
 {
     test_nullary_function<std::function<int()>, int>();
     test_unary_function  <std::function<double(int)>, double, int>();
     test_binary_function <std::function<double(int, char)>, double, int, char>();
     test_other_function  <std::function<double(int, char, double)>, double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/func.wrap/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
index 1b0a1c63f16..29767a58c48 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_and.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_and<int> F;
     const F f = F();
@@ -48,4 +48,6 @@ int main()
     constexpr bool bar = std::logical_and<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
index 2c0c9f3bc90..e93fd06fdd5 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_not.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_not<int> F;
     const F f = F();
@@ -38,4 +38,6 @@ int main()
     constexpr bool bar = std::logical_not<> () (36);
     static_assert ( !bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
index 497a9d981f1..abe536572ea 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/logical_or.pass.cpp
@@ -16,7 +16,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_or<int> F;
     const F f = F();
@@ -47,4 +47,6 @@ int main()
     constexpr bool bar = std::logical_or<> () (36.0, 36);
     static_assert ( bar, "" );
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp b/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
index 3aa24c44330..eb590b31a01 100644
--- a/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/logical.operations/transparent.pass.cpp
@@ -22,7 +22,7 @@ public:
 };
 
 
-int main ()
+int main(int, char**)
 {
     static_assert ( !is_transparent<std::logical_and<int>>::value, "" );
     static_assert ( !is_transparent<std::logical_and<std::string>>::value, "" );
diff --git a/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
index ca8b76711cf..713afc66562 100644
--- a/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/binary_negate.depr_in_cxx17.fail.cpp
@@ -28,7 +28,9 @@ struct Predicate {
     bool operator()(first_argument_type, second_argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::binary_negate<Predicate> f((Predicate())); // expected-error{{'binary_negate<Predicate>' is deprecated}}
     (void)f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
index 1e7edcb3242..41541c10ff1 100644
--- a/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/binary_negate.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::binary_negate<std::logical_and<int> > F;
     const F f = F(std::logical_and<int>());
@@ -25,4 +25,6 @@ int main()
     assert( f(36, 0));
     assert( f(0, 36));
     assert( f(0, 0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
index 9fbe6db66f9..407cbd4fc26 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not1.depr_in_cxx17.fail.cpp
@@ -27,6 +27,8 @@ struct Predicate {
     bool operator()(argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::not1(Predicate()); // expected-error{{'not1<Predicate>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
index 33268222b5d..07c160a97ab 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not1.pass.cpp
@@ -13,9 +13,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_not<int> F;
     assert(std::not1(F())(36));
     assert(!std::not1(F())(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
index 032ce3429dc..24178e0a05d 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not2.depr_in_cxx17.fail.cpp
@@ -28,6 +28,8 @@ struct Predicate {
     bool operator()(first_argument_type, second_argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::not2(Predicate()); // expected-error{{'not2<Predicate>' is deprecated}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
index 208d33b4a3e..d9f3c95fd89 100644
--- a/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/not2.pass.cpp
@@ -13,11 +13,13 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::logical_and<int> F;
     assert(!std::not2(F())(36, 36));
     assert( std::not2(F())(36, 0));
     assert( std::not2(F())(0, 36));
     assert( std::not2(F())(0, 0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp b/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
index 99cdf136d64..15a0a277826 100644
--- a/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/unary_negate.depr_in_cxx17.fail.cpp
@@ -27,7 +27,9 @@ struct Predicate {
     bool operator()(argument_type) const { return true; }
 };
 
-int main() {
+int main(int, char**) {
     std::unary_negate<Predicate> f((Predicate())); // expected-error{{'unary_negate<Predicate>' is deprecated}}
     (void)f;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
index ec00c3e32a2..54fd54f3969 100644
--- a/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/negators/unary_negate.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::unary_negate<std::logical_not<int> > F;
     const F f = F(std::logical_not<int>());
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<F::result_type, bool>::value), "" );
     assert(f(36));
     assert(!f(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
index 5e67db520fb..c15989f003e 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.access/conversion.pass.cpp
@@ -30,7 +30,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -41,4 +41,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
index 16ce961126c..3ef0cdda869 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.assign/copy_assign.pass.cpp
@@ -42,7 +42,7 @@ test_function()
     assert(&r2.get() == &f);
 }
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -53,4 +53,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
index 64726b53ef8..355047d98ce 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/copy_ctor.pass.cpp
@@ -30,7 +30,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -41,4 +41,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
index f7a6670b431..f02a9974d7d 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.fail.cpp
@@ -17,7 +17,9 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::reference_wrapper<const int> r(3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
index 2cbb1a010f1..a43d0fd2510 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.const/type_ctor.pass.cpp
@@ -29,7 +29,7 @@ test(T& t)
 
 void f() {}
 
-int main()
+int main(int, char**)
 {
     void (*fp)() = f;
     test(fp);
@@ -40,4 +40,6 @@ int main()
     test(i);
     const int j = 0;
     test(j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
index b16a4b476c3..d4cb421f53e 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_1.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::reference_wrapper<const int> r = std::cref(i);
     assert(&r.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
index 3023f8da2a3..093b7e230fd 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/cref_2.pass.cpp
@@ -15,10 +15,12 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const int i = 0;
     std::reference_wrapper<const int> r1 = std::cref(i);
     std::reference_wrapper<const int> r2 = std::cref(r1);
     assert(&r2.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
index 9e283d1bfaf..c07028d21dd 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.fail.cpp
@@ -22,7 +22,9 @@ struct A {};
 
 const A source() {return A();}
 
-int main()
+int main(int, char**)
 {
     std::reference_wrapper<const A> r = std::ref(source());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
index a8af5aa4cfe..f64d8ad8cae 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_1.pass.cpp
@@ -15,9 +15,11 @@
 #include <functional>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     std::reference_wrapper<int> r = std::ref(i);
     assert(&r.get() == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
index fee5009a73b..4fdaf992c64 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.helpers/ref_2.pass.cpp
@@ -22,7 +22,7 @@ bool is5 ( int i ) { return i == 5; }
 template <typename T>
 bool call_pred ( T pred ) { return pred(5); }
 
-int main()
+int main(int, char**)
 {
     {
     int i = 0;
@@ -39,4 +39,6 @@ int main()
     assert(call_pred(std::ref(cp)));
     assert(cp.count() == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
index 6302c51b8ad..d54d5184c65 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.fail.cpp
@@ -45,7 +45,9 @@ test_int_1()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_int_1();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
index 425bc6df0c8..fd31041330d 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke.pass.cpp
@@ -319,10 +319,12 @@ testint_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_1();
     test_int_1();
     test_void_2();
     testint_2();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
index 37d7cfca9de..67cf51f3359 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_int_0.pass.cpp
@@ -69,7 +69,9 @@ struct A_void_1
     }
 };
 
-int main()
+int main(int, char**)
 {
     test_int_0();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
index 735bfd890dd..18e65531333 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/refwrap.invoke/invoke_void_0.pass.cpp
@@ -61,7 +61,9 @@ test_void_0()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_void_0();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
index ef46e15d0a0..d17ab8100ef 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/type.pass.cpp
@@ -17,7 +17,7 @@
 
 class C {};
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::reference_wrapper<C>::type,
                                                        C>::value), "");
@@ -33,4 +33,6 @@ int main()
                                                        int*(C::*)(double*)>::value), "");
     static_assert((std::is_same<std::reference_wrapper<int (C::*)(double*) const volatile>::type,
                                                        int (C::*)(double*) const volatile>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
index 14a06a9c316..17eef26f07a 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/type_properties.pass.cpp
@@ -52,7 +52,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<double>();
@@ -60,4 +60,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<MoveOnly>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
index 9aaa2827997..1987898393c 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_ref_decay.pass.cpp
@@ -28,7 +28,7 @@ void check() {
 
 struct T { };
 
-int main() {
+int main(int, char**) {
   check<T,             T>();
   check<T&,            T>();
   check<T const,       T>();
@@ -54,4 +54,6 @@ int main() {
   check<std::reference_wrapper<T[3]>&,     T (&)[3]>();
   check<std::reference_wrapper<T ()>,      T (&)()>();
   check<std::reference_wrapper<T ()>&,     T (&)()>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
index f6d48a51e8b..209d5e2a0bc 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/unwrap_reference.pass.cpp
@@ -39,7 +39,7 @@ void check() {
 
 struct T { };
 
-int main() {
+int main(int, char**) {
   check<T>();
   check<int>();
   check<float>();
@@ -47,4 +47,6 @@ int main() {
   check<T*>();
   check<int*>();
   check<float*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp b/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
index 50cda116932..5a6a41fdbe0 100644
--- a/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/refwrap/weak_result.pass.cpp
@@ -68,7 +68,7 @@ public:
     static const bool value = sizeof(test<T>(0)) == 1;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::reference_wrapper<functor1>::result_type,
                                 char>::value), "");
@@ -93,4 +93,6 @@ int main()
     static_assert(has_result_type<std::reference_wrapper<functor3> >::value, "");
     static_assert(!has_result_type<std::reference_wrapper<functor4> >::value, "");
     static_assert(!has_result_type<std::reference_wrapper<C> >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
index 90ab8e1bb79..8f6c3e14e2c 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enabled_hashes.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
index b824b51ea79..2e36b4c5531 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enum.fail.cpp
@@ -16,8 +16,10 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     X x;
     size_t h = std::hash<X>{} ( x );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
index 96c667febcb..e172bc2f346 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/enum.pass.cpp
@@ -49,7 +49,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<Cardinals>();
 
@@ -59,4 +59,6 @@ int main()
     test<EightBitColors>();
 
     test<Fruits>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
index 1ab1643413a..31b1b2d07e4 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/floating.pass.cpp
@@ -64,9 +64,11 @@ test()
     assert(pinf != ninf);
 }
 
-int main()
+int main(int, char**)
 {
     test<float>();
     test<double>();
     test<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
index 761c76dc141..dbd44a88207 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/integral.pass.cpp
@@ -46,7 +46,7 @@ test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>();
     test<char>();
@@ -108,4 +108,6 @@ int main()
     test<__int128_t>();
     test<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
index 6efcebc4ebe..c47f8fa76a4 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/non_enum.pass.cpp
@@ -22,7 +22,7 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     using H = std::hash<X>;
     static_assert(!std::is_default_constructible<H>::value, "");
@@ -34,4 +34,6 @@ int main()
     static_assert(!std::is_invocable<H, X&>::value, "");
     static_assert(!std::is_invocable<H, X const&>::value, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp b/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
index cbf2c736eab..17dfdce2d4a 100644
--- a/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/function.objects/unord.hash/pointer.pass.cpp
@@ -52,8 +52,10 @@ void test_nullptr()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int*>();
     test_nullptr();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
index 8da459ff81d..90b09132d9e 100644
--- a/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.general/integer_seq.pass.cpp
@@ -21,7 +21,7 @@ auto extract ( const AtContainer &t, const std::integer_sequence<T, I...> )
 -> decltype ( std::make_tuple ( std::get<I>(t)... ))
 {     return  std::make_tuple ( std::get<I>(t)... ); }
 
-int main()
+int main(int, char**)
 {
 //  Make a couple of sequences
     using int3    = std::make_integer_sequence<int, 3>;     // generates int:    0,1,2
@@ -76,4 +76,6 @@ int main()
     auto tsizemix = extract ( tup, sizemix ());
     static_assert ( std::tuple_size<decltype(tsizemix)>::value == sizemix::size (), "tsizemix size wrong");
     assert ( tsizemix == std::make_tuple ( 11, 11, 12, 13, 15 ));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
index 44ffb017876..248b346e33a 100644
--- a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.fail.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 11
 
@@ -36,4 +36,6 @@ int main()
 X
 
 #endif  // TEST_STD_VER > 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
index 653d2988a7c..a8e14c9a9cd 100644
--- a/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.intseq/integer_seq.pass.cpp
@@ -22,7 +22,7 @@
 #include <cstddef>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
 //  Make a few of sequences
     using int3    = std::integer_sequence<int, 3, 2, 1>;
@@ -42,4 +42,6 @@ int main()
 
     static_assert ( std::is_same<bool0::value_type, bool>::value, "bool0 type wrong" );
     static_assert ( bool0::size() == 0, "bool0 size wrong" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
index 2f2a6608b2c..ec2e8cc7c2c 100644
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.fail.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   typedef std::make_integer_sequence<int, -3> MakeSeqT;
 
@@ -33,4 +33,6 @@ int main()
 #else
     MakeSeqT i; // expected-error@utility:* {{static_assert failed "std::make_integer_sequence must have a non-negative sequence length"}}
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
index 3c522c73bf9..50b49dd725e 100644
--- a/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/intseq.make/make_integer_seq.pass.cpp
@@ -17,7 +17,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_same<std::make_integer_sequence<int, 0>, std::integer_sequence<int>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<int, 1>, std::integer_sequence<int, 0>>::value, "");
@@ -28,4 +28,6 @@ int main()
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 1>, std::integer_sequence<unsigned long long, 0>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 2>, std::integer_sequence<unsigned long long, 0, 1>>::value, "");
     static_assert(std::is_same<std::make_integer_sequence<unsigned long long, 3>, std::integer_sequence<unsigned long long, 0, 1, 2>>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/intseq/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
index b095dbfaf16..1a58726a854 100644
--- a/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.tag/allocator_arg.pass.cpp
@@ -15,7 +15,9 @@
 
 void test(std::allocator_arg_t) {}
 
-int main()
+int main(int, char**)
 {
     test(std::allocator_arg);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
index 60f267fa5e3..47cfbb0494b 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.fail.cpp
@@ -42,9 +42,11 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
     A<int> a;
     std::allocator_traits<A<int> >::allocate(a, 10);          // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     std::allocator_traits<A<int> >::allocate(a, 10, nullptr); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
index a892be03d9d..0ac2f266e81 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate.pass.cpp
@@ -33,7 +33,7 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
   {
     A<int> a;
@@ -45,4 +45,6 @@ int main()
     Alloc a;
     assert(std::allocator_traits<Alloc >::allocate(a, 10) == reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xDEADBEEF)));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
index 9d4631740b0..e9524716398 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/allocate_hint.pass.cpp
@@ -53,7 +53,7 @@ struct B
 };
 
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
   {
@@ -77,4 +77,6 @@ int main()
     Alloc b;
     assert(std::allocator_traits<Alloc >::allocate(b, 11, nullptr) == reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xFEADBEEF)));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
index 252d99a7a74..67a2e8f4ac8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/construct.pass.cpp
@@ -81,7 +81,7 @@ struct A2
 
 int A2::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A0::count = 0;
@@ -149,4 +149,6 @@ int main()
         assert(b_construct == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
index 94f10b64dba..c738416e01d 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/deallocate.pass.cpp
@@ -36,7 +36,7 @@ struct A
     }
 };
 
-int main()
+int main(int, char**)
 {
   {
     A<int> a;
@@ -51,4 +51,6 @@ int main()
     std::allocator_traits<Alloc >::deallocate(a, reinterpret_cast<VT*>(static_cast<std::uintptr_t>(0xDEADBEEF)), 10);
     assert(called == 1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
index 677c647a27d..70890d8512f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/destroy.pass.cpp
@@ -54,7 +54,7 @@ struct A0
 
 int A0::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A0::count = 0;
@@ -86,4 +86,6 @@ int main()
         assert(b_destroy == 1);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
index a51ec6e95ac..b758c9add8c 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/max_size.pass.cpp
@@ -42,7 +42,7 @@ struct B
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         B<int> b;
@@ -74,4 +74,6 @@ int main()
         static_assert(noexcept(std::allocator_traits<std::allocator<int>>::max_size(a)) == true, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
index 9594531dad9..be837670dd3 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.members/select_on_container_copy_construction.pass.cpp
@@ -47,7 +47,7 @@ struct B
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
         A<int> a;
@@ -73,4 +73,6 @@ int main()
         assert(std::allocator_traits<B<int> >::select_on_container_copy_construction(b).id == 100);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
index f153d95b4aa..756958b584f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_pointer.pass.cpp
@@ -55,7 +55,7 @@ private:
   typedef void const_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::const_pointer, Ptr<const char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::const_pointer, const char*>::value), "");
@@ -63,4 +63,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::const_pointer, const char*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
index 3acedde6544..4fcc2fb7c15 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/const_void_pointer.pass.cpp
@@ -57,7 +57,7 @@ private:
     typedef int const_void_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::const_void_pointer, Ptr<const void> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::const_void_pointer, const void*>::value), "");
@@ -65,4 +65,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::const_void_pointer, const void*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
index b0ee1635083..35721f1cbba 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/difference_type.pass.cpp
@@ -66,7 +66,7 @@ struct pointer_traits<C<char>::pointer>
 
 }
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::difference_type, short>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::difference_type, std::ptrdiff_t>::value), "");
@@ -74,4 +74,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::difference_type, std::ptrdiff_t>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
index fae61849331..42b0fbab19c 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/is_always_equal.pass.cpp
@@ -39,7 +39,7 @@ struct C
     int not_empty_;  // some random member variable
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::is_always_equal, std::true_type>::value), "");
@@ -48,4 +48,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<A<const char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<const char> >::is_always_equal, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<C<const char> >::is_always_equal, std::false_type>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
index 60f3d257afd..58b306660a8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/pointer.pass.cpp
@@ -43,11 +43,13 @@ private:
     typedef void pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::pointer, Ptr<char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::pointer, char*>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::pointer, char*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
index c8451b2a975..b049159e2d1 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_copy_assignment.pass.cpp
@@ -43,11 +43,13 @@ private:
     typedef std::true_type propagate_on_container_copy_assignment;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_copy_assignment, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_copy_assignment, std::false_type>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_copy_assignment, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
index 7c58ac8811b..602ba96d5c1 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_move_assignment.pass.cpp
@@ -44,11 +44,13 @@ private:
 };
 
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_move_assignment, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_move_assignment, std::false_type>::value), "");
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_move_assignment, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
index 7a6bcd460a6..5ae53015fa3 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/propagate_on_container_swap.pass.cpp
@@ -42,11 +42,13 @@ private:
     typedef std::true_type propagate_on_container_swap;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::propagate_on_container_swap, std::true_type>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::propagate_on_container_swap, std::false_type>::value), "");
  #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<C<char> >::propagate_on_container_swap, std::false_type>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
index eaadeb17048..d0d8476a89a 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/rebind_alloc.pass.cpp
@@ -80,7 +80,7 @@ struct G {
     };
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<A<char> >::rebind_alloc<double>, ReboundA<double> >::value), "");
@@ -97,4 +97,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<D<int, char> >::rebind_alloc<double>::other, D<double, char> >::value), "");
     static_assert((std::is_same<std::allocator_traits<E<char> >::rebind_alloc<double>::other, E<double> >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
index 42b29a39c7b..cd74671390e 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/size_type.pass.cpp
@@ -62,7 +62,7 @@ struct pointer_traits<C<char>::pointer>
 
 }
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::size_type, unsigned short>::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::size_type,
@@ -72,4 +72,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::size_type, unsigned short>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
index 687d892f0cf..55954dc7091 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator.traits.types/void_pointer.pass.cpp
@@ -56,7 +56,7 @@ private:
     typedef void void_pointer;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::void_pointer, Ptr<void> >::value), "");
     static_assert((std::is_same<std::allocator_traits<B<char> >::void_pointer, void*>::value), "");
@@ -64,4 +64,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<D<char> >::void_pointer, void*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
index d5977f0a28f..840ad820e1f 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/allocator_type.pass.cpp
@@ -24,7 +24,9 @@ struct A
     typedef T value_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::allocator_type, A<char> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
index 475ab04b839..01aac9445c8 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/rebind_traits.pass.cpp
@@ -62,7 +62,7 @@ struct E
     template <class U> struct rebind {typedef ReboundA<U> otter;};
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::allocator_traits<A<char> >::rebind_traits<double>, std::allocator_traits<ReboundA<double> > >::value), "");
@@ -77,4 +77,6 @@ int main()
     static_assert((std::is_same<std::allocator_traits<D<int, char> >::rebind_traits<double>::other, std::allocator_traits<D<double, char> > >::value), "");
     static_assert((std::is_same<std::allocator_traits<E<char> >::rebind_traits<double>::other, std::allocator_traits<E<double> > >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp b/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
index dec3a41e374..047d40d5c89 100644
--- a/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.traits/value_type.pass.cpp
@@ -24,7 +24,9 @@ struct A
     typedef T value_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator_traits<A<char> >::value_type, char>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.construction/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
index 5b7f710eab0..d9d4fc3d837 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/allocator.uses.trait/uses_allocator.pass.cpp
@@ -47,7 +47,7 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<false, int, std::allocator<int> >();
     test<true, std::vector<int>, std::allocator<int> >();
@@ -71,4 +71,6 @@ int main()
 // #if TEST_STD_VER >= 11
 //     static_assert((!std::uses_allocator<E, int>::value), "");
 // #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/allocator.uses/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
index a8d90b1ce6f..7e6c6780070 100644
--- a/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/c.malloc/nothing_to_do.pass.cpp
@@ -8,6 +8,8 @@
 
 // <cstdlib> and <cstring> are already tested elsewhere
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
index 7aa2dbfeb03..57946be085a 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.ctor.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::allocator<char> AC;
@@ -46,4 +46,6 @@ int main()
     (void) a3;
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
index b38daf8e912..63412bce1f4 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.globals/eq.pass.cpp
@@ -21,10 +21,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::allocator<int> a1;
     std::allocator<int> a2;
     assert(a1 == a2);
     assert(!(a1 != a2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
index bb1bb4f11ee..c4ff55d0eab 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/address.pass.cpp
@@ -31,8 +31,10 @@ struct A
     void operator&() const {}
 };
 
-int main()
+int main(int, char**)
 {
     test_address<int>();
     test_address<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
index df4124f51ed..889804f3b71 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.fail.cpp
@@ -19,9 +19,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::allocator<int> a;
     a.allocate(3);          // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
     a.allocate(3, nullptr); // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
index 14e5a8a3c79..8392cbdb709 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp
@@ -99,7 +99,7 @@ void test_aligned() {
   }
 }
 
-int main() {
+int main(int, char**) {
     test_aligned<1>();
     test_aligned<2>();
     test_aligned<4>();
@@ -108,4 +108,6 @@ int main() {
     test_aligned<MaxAligned>();
     test_aligned<OverAligned>();
     test_aligned<OverAligned * 2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
index 09a9bd912d0..685e02ef393 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/allocate.size.pass.cpp
@@ -39,8 +39,10 @@ void test()
     test_max<T> ((size_t) -1);                     // way too large
 }
 
-int main()
+int main(int, char**)
 {
     test<double>();
     LIBCPP_ONLY(test<const double>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
index 322881b1536..96954e04b08 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/construct.pass.cpp
@@ -53,7 +53,7 @@ public:
 };
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     {
     std::allocator<A> a;
@@ -139,4 +139,6 @@ int main()
     assert(move_only_constructed == 0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
index 50076ce02f4..c2094bc044a 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator.members/max_size.pass.cpp
@@ -18,9 +18,11 @@
 
 int new_called = 0;
 
-int main()
+int main(int, char**)
 {
     const std::allocator<int> a;
     std::size_t M = a.max_size();
     assert(M > 0xFFFF && M <= (std::numeric_limits<std::size_t>::max() / sizeof(int)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
index 375b96f831b..bc89c62a847 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_pointers.pass.cpp
@@ -108,7 +108,7 @@ void test_void_pointer()
 
 struct Foo { int x; };
 
-int main()
+int main(int, char**)
 {
     test_pointer<std::allocator<char>> ();
     test_pointer<std::allocator<int>> ();
@@ -117,7 +117,9 @@ int main()
     test_void_pointer<std::allocator<char>> ();
     test_void_pointer<std::allocator<int>> ();
     test_void_pointer<std::allocator<Foo>> ();
+
+  return 0;
 }
 #else
-int main() {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
index 9cd5815645d..0bff67efbd9 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_types.pass.cpp
@@ -33,7 +33,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator<char>::size_type, std::size_t>::value), "");
     static_assert((std::is_same<std::allocator<char>::difference_type, std::ptrdiff_t>::value), "");
@@ -53,4 +53,6 @@ int main()
     a2 = a;
     std::allocator<int> a3 = a2;
     ((void)a3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp b/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
index 1f13c8be6ca..528902d2112 100644
--- a/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
+++ b/libcxx/test/std/utilities/memory/default.allocator/allocator_void.pass.cpp
@@ -22,7 +22,7 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::allocator<void>::pointer, void*>::value), "");
     static_assert((std::is_same<std::allocator<void>::const_pointer, const void*>::value), "");
@@ -32,4 +32,6 @@ int main()
     std::allocator<void> a;
     std::allocator<void> a2 = a;
     a2 = a;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp b/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
index 0fd45fd913c..7d55974dd93 100644
--- a/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.conversion/to_address.pass.cpp
@@ -99,7 +99,7 @@ struct pointer_traits<::P4>
 int n = 0;
 static_assert(std::to_address(&n) == &n);
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     ASSERT_NOEXCEPT(std::to_address(&i));
@@ -116,4 +116,6 @@ int main()
     P4 p4(&i);
     ASSERT_NOEXCEPT(std::to_address(p4));
     assert(std::to_address(p4) == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
index 867bd46cd29..3eaedab1670 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/difference_type.pass.cpp
@@ -18,7 +18,9 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<double*>::difference_type, std::ptrdiff_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
index 42db90ff6ef..505881ddeea 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/element_type.pass.cpp
@@ -18,7 +18,9 @@
 #include <memory>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<const short*>::element_type, const short>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
index 4a74b5d5894..110a993dc66 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.pass.cpp
@@ -24,8 +24,10 @@ struct A
     typedef char difference_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::pointer, A>::value), "");
     static_assert((std::is_same<std::pointer_traits<int*>::pointer, int*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
index 0b412dac463..9e6a48930e2 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp
@@ -34,7 +34,7 @@ public:
         {return A(&et);}
 };
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -45,4 +45,6 @@ int main()
     {
         (std::pointer_traits<A<void> >::element_type)0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
index 7e08235399e..d4d763c69ea 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/difference_type.pass.cpp
@@ -52,7 +52,7 @@ private:
   typedef int difference_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::difference_type, char>::value), "");
     static_assert((std::is_same<std::pointer_traits<B>::difference_type, std::ptrdiff_t>::value), "");
@@ -62,4 +62,6 @@ int main()
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<F<int>>::difference_type, std::ptrdiff_t>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
index 8184d2d0027..c0efdeab0b3 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/element_type.pass.cpp
@@ -53,7 +53,7 @@ private:
   typedef int element_type;
 };
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::pointer_traits<A>::element_type, char>::value), "");
     static_assert((std::is_same<std::pointer_traits<B<int> >::element_type, char>::value), "");
@@ -64,4 +64,6 @@ int main()
     static_assert((std::is_same<std::pointer_traits<F<double>>::element_type, double>::value), "");
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
index 407f4bcfb9f..a79f3391664 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer.traits.types/rebind.pass.cpp
@@ -81,7 +81,7 @@ struct G
 #endif
 
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<A<int*> >::rebind<double*>, A<double*> >::value), "");
@@ -101,4 +101,6 @@ int main()
     static_assert((std::is_same<std::pointer_traits<D<char, int> >::rebind<double>::other, D1<double, int> >::value), "");
     static_assert((std::is_same<std::pointer_traits<E<char, int> >::rebind<double>::other, E<double, int> >::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
index 968d3ee1e72..e9b858c7fd9 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp
@@ -35,9 +35,11 @@ bool check() {
     return true;
 }
 
-int main() {
+int main(int, char**) {
     check();
 #if TEST_STD_VER > 17
     static_assert(check(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp b/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
index 823d4f11f23..f64213c9b88 100644
--- a/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
+++ b/libcxx/test/std/utilities/memory/pointer.traits/rebind.pass.cpp
@@ -20,11 +20,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<std::pointer_traits<int*>::rebind<double>, double*>::value), "");
 #else
     static_assert((std::is_same<std::pointer_traits<int*>::rebind<double>::other, double*>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp b/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
index c7a181eb79e..3d0216cce53 100644
--- a/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
+++ b/libcxx/test/std/utilities/memory/ptr.align/align.pass.cpp
@@ -13,7 +13,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const unsigned N = 20;
     char buf[N];
@@ -80,4 +80,6 @@ int main()
     assert(p == &buf[0]);
     assert(r == nullptr);
     assert(s == N);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
index 956e6b1187c..f6310c7bc91 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.pass.cpp
@@ -26,7 +26,7 @@ struct nothing {
     }
 };
 
-int main()
+int main(int, char**)
 {
     {
     int i;
@@ -47,4 +47,6 @@ int main()
     };
     assert(std::addressof(n) == (void*)std::addressof(i));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
index c12bf41e8ea..f7033014d37 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/addressof.temp.fail.cpp
@@ -15,11 +15,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 14
     const int *p = std::addressof<const int>(0);
 #else
 #error
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
index c042dd5c37b..f14a0e7fc89 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.addressof/constexpr_addressof.pass.cpp
@@ -32,10 +32,12 @@ constexpr int i = 0;
 constexpr double d = 0.0;
 constexpr A a{};
 
-int main()
+int main(int, char**)
 {
     static_assert(std::addressof(i) == &i, "");
     static_assert(std::addressof(d) == &d, "");
     constexpr const A* ap = std::addressof(a);
     static_assert(&ap->n == &a.n, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
index f812bb85a62..4dbc20aba39 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy.pass.cpp
@@ -30,7 +30,7 @@ struct Counted {
 };
 int Counted::count = 0;
 
-int main()
+int main(int, char**)
 {
     using It = forward_iterator<Counted*>;
     const int N = 5;
@@ -43,4 +43,6 @@ int main()
     assert(Counted::count == 4);
     std::destroy(It(p), It(p + 4));
     assert(Counted::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
index 28450faa10f..d505222b02d 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_at.pass.cpp
@@ -41,7 +41,7 @@ struct DCounted : VCounted {
     friend void operator&(DCounted) = delete;
 };
 
-int main()
+int main(int, char**)
 {
     {
     void* mem1 = std::malloc(sizeof(Counted));
@@ -74,4 +74,6 @@ int main()
     std::free(mem1);
     std::free(mem2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
index 90836b23355..0dcc8e5a657 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/specialized.destroy/destroy_n.pass.cpp
@@ -30,7 +30,7 @@ struct Counted {
 };
 int Counted::count = 0;
 
-int main()
+int main(int, char**)
 {
     using It = forward_iterator<Counted*>;
     const int N = 5;
@@ -45,4 +45,6 @@ int main()
     It it = std::destroy_n(It(p), 4);
     assert(it == It(p+4));
     assert(Counted::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
index bd9ef7b403f..67dd6fbd298 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct.pass.cpp
@@ -103,9 +103,11 @@ void test_value_initialized()
     assert(pool[4] == -1);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
index d2f6e094a85..1052355a4f2 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.default/uninitialized_default_construct_n.pass.cpp
@@ -107,9 +107,11 @@ void test_value_initialized()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
index 50ce1224848..5dfcd83fe9b 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct.pass.cpp
@@ -102,9 +102,11 @@ void test_value_initialized()
     assert(pool[4] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
index 4d89f9cac4c..e43102ba4aa 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.construct.value/uninitialized_value_construct_n.pass.cpp
@@ -107,8 +107,10 @@ void test_value_initialized()
     assert(pool[4] == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_value_initialized();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
index b81d561e089..2618bd5339c 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -85,4 +85,6 @@ int main()
         }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
index c3f46bebe67..1a237a7929d 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.copy/uninitialized_copy_n.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -84,4 +84,6 @@ int main()
         assert(  p[i].i_ == i);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
index 5c177663e40..4dfde4f6e87 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill.n/uninitialized_fill_n.pass.cpp
@@ -46,7 +46,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -84,4 +84,6 @@ int main()
     }
 
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
index f7790fc4519..1996ec6c6ff 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.fill/uninitialized_fill.pass.cpp
@@ -47,7 +47,7 @@ struct Nasty
 
 int Nasty::counter_ = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const int N = 5;
@@ -81,4 +81,6 @@ int main()
     for (int i = 0; i < N; ++i)
         assert(bp[i].i_ == 23);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
index a0717e61b2c..e17f5734bb2 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move.pass.cpp
@@ -107,7 +107,9 @@ void test_counted()
     assert(Counted::count == 0);
 }
 
-int main() {
+int main(int, char**) {
     test_counted();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
index 75538407421..ee364aaf5b9 100644
--- a/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
+++ b/libcxx/test/std/utilities/memory/specialized.algorithms/uninitialized.move/uninitialized_move_n.pass.cpp
@@ -109,8 +109,10 @@ void test_counted()
     assert(Counted::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test_counted();
     test_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
index 531158ba158..5355d09ac26 100644
--- a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
+++ b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.base.pass.cpp
@@ -36,7 +36,7 @@ public:
     A* operator& () DELETE_FUNCTION;
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 14
     typedef std::aligned_storage<3*sizeof(A), std::alignment_of<A>::value>::type
@@ -54,4 +54,6 @@ int main()
         assert(it.base() == ap + 1);  // next place to write
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
index 90bb956fc03..2b9b33fd9b9 100644
--- a/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/storage.iterator/raw_storage_iterator.pass.cpp
@@ -36,7 +36,7 @@ public:
     A* operator& () DELETE_FUNCTION;
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef A S;
@@ -67,4 +67,6 @@ int main()
     assert(ap->get() == 1); // original value
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
index fd818577b06..db71c69bf26 100644
--- a/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/overaligned.pass.cpp
@@ -25,10 +25,12 @@ struct alignas(32) A {
     int field;
 };
 
-int main()
+int main(int, char**)
 {
     std::pair<A*, std::ptrdiff_t> ip = std::get_temporary_buffer<A>(5);
     assert(!(ip.first == nullptr) ^ (ip.second == 0));
     assert(reinterpret_cast<uintptr_t>(ip.first) % alignof(A) == 0);
     std::return_temporary_buffer(ip.first);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp b/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
index 22efde4af8f..32a58e5a657 100644
--- a/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/temporary.buffer/temporary_buffer.pass.cpp
@@ -19,10 +19,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::pair<int*, std::ptrdiff_t> ip = std::get_temporary_buffer<int>(5);
     assert(ip.first);
     assert(ip.second == 5);
     std::return_temporary_buffer(ip.first);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
index c9d1c8b4697..bc6846fe7f5 100644
--- a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
+++ b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.fail.cpp
@@ -26,9 +26,11 @@
 #include "min_allocator.h"
 #include "deleter_types.h"
 
-int main()
+int main(int, char**)
 {
     std::unique_ptr<int, PointerDeleter<int>> p;
     std::ostringstream os;
     os << p; // expected-error {{invalid operands to binary expression}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
index e350a0385d6..b9b158a9d2b 100644
--- a/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
+++ b/libcxx/test/std/utilities/memory/unique.ptr/unique.ptr.special/io.pass.cpp
@@ -21,11 +21,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::unique_ptr<int> p(new int(3));
     std::ostringstream os;
     assert(os.str().empty());
     os << p;
     assert(!os.str().empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
index 5c99a9721a0..a2b6cf22ed8 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_no_pointers.pass.cpp
@@ -13,10 +13,12 @@
 
 #include <memory>
 
-int main()
+int main(int, char**)
 {
     char* p = new char[10];
     std::declare_no_pointers(p, 10);
     std::undeclare_no_pointers(p, 10);
     delete [] p;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
index 4a71817d403..c923089fa97 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/declare_reachable.pass.cpp
@@ -14,10 +14,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int* p = new int;
     std::declare_reachable(p);
     assert(std::undeclare_reachable(p) == p);
     delete p;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp b/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
index 4fc2e010f79..2fea98364b4 100644
--- a/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.dynamic.safety/get_pointer_safety.pass.cpp
@@ -22,7 +22,7 @@ void test_pr26961() {
   assert(d == std::get_pointer_safety());
 }
 
-int main()
+int main(int, char**)
 {
   {
     std::pointer_safety r = std::get_pointer_safety();
@@ -33,4 +33,6 @@ int main()
   {
     test_pr26961();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
index 0f7c44fd8fd..fe7567eebc1 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.enab/enable_shared_from_this.pass.cpp
@@ -52,7 +52,7 @@ struct PrivateBase : private std::enable_shared_from_this<PrivateBase> {
 };
 
 
-int main()
+int main(int, char**)
 {
     {  // https://bugs.llvm.org/show_bug.cgi?id=18843
     std::shared_ptr<T const> t1(new T);
@@ -167,4 +167,6 @@ int main()
         assert(my_weak.lock().get() == ptr);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
index bd7f644c3ec..440fa8ac480 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
index 8db542c0794..34717ad4256 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_shared_ptr.pass.cpp
@@ -25,7 +25,7 @@
 struct A {};
 #endif
 
-int main()
+int main(int, char**)
 {
   {
     int* ptr = new int;
@@ -40,4 +40,6 @@ int main()
     test_hash_enabled_for_type<std::shared_ptr<A>>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
index 4f942f6c2d9..5cae6ca7d45 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.hash/hash_unique_ptr.pass.cpp
@@ -60,7 +60,7 @@ struct A {};
 
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
   {
     int* ptr = new int;
@@ -99,4 +99,6 @@ int main()
 #endif
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
index 45c82c4bafa..7737cfd4da0 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -51,4 +51,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
index d1589aaddba..9198ca68cd8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_strong_explicit.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -56,4 +56,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
index fb09a19fd05..da52811c9c0 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -51,4 +51,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
index 2a9b6ce1244..703bf008f4f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_compare_exchange_weak_explicit.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -56,4 +56,6 @@ int main()
         assert(*v == 4);
         assert(*w == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
index cf6ad5b0037..b51a24aefb9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -37,4 +37,6 @@ int main()
         assert(*p == 3);
         assert(*r == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
index f177420fe94..b59b515a5c2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_exchange_explicit.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(4));
@@ -37,4 +37,6 @@ int main()
         assert(*p == 3);
         assert(*r == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
index 3b267f99d09..e8bb64dccb6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_is_lock_free.pass.cpp
@@ -23,10 +23,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<int> p(new int(3));
         assert(std::atomic_is_lock_free(&p) == false);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
index b36580ef217..63416faf329 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load.pass.cpp
@@ -28,11 +28,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p(new int(3));
         std::shared_ptr<int> q = std::atomic_load(&p);
         assert(*q == *p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
index 40f6b49d6c6..0708f874b26 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_load_explicit.pass.cpp
@@ -28,11 +28,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<int> p(new int(3));
         std::shared_ptr<int> q = std::atomic_load_explicit(&p, std::memory_order_relaxed);
         assert(*q == *p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
index 3c6de40f117..42d7099a9df 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p;
@@ -36,4 +36,6 @@ int main()
         std::atomic_store(&p, r);
         assert(*p == *r);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
index dd4001a82ff..7da4de3fa47 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared.atomic/atomic_store_explicit.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<int> p;
@@ -36,4 +36,6 @@ int main()
         std::atomic_store_explicit(&p, r, std::memory_order_seq_cst);
         assert(*p == *r);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
index 4a96f8181b2..c3aedd5b1ad 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/types.pass.cpp
@@ -22,10 +22,12 @@
 
 struct A;  // purposefully incomplete
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::shared_ptr<A>::element_type, A>::value), "");
 #if TEST_STD_VER > 14
     static_assert((std::is_same<std::shared_ptr<A>::weak_type, std::weak_ptr<A>>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
index babf1c6ee5b..209e3fe71af 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.getdeleter/get_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         {
@@ -63,4 +63,6 @@ int main()
         std::default_delete<A>* d = std::get_deleter<std::default_delete<A> >(p);
         assert(d == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
index 69ad9513b6c..a154a121c7f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/auto_ptr_Y.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::auto_ptr<A> pA(new A);
@@ -110,4 +110,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
index 6d2000c1375..e362f4d8d4e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -117,4 +117,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
index 23b587d0b7d..2b666315ef2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -117,4 +117,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
index a3ba5877f49..6787c33c297 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_Y_rv.pass.cpp
@@ -41,7 +41,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -119,4 +119,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
index 8c63b14b27d..e921a099189 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/shared_ptr_rv.pass.cpp
@@ -41,7 +41,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -119,4 +119,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
index b7fc447b057..4abe371bc07 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.assign/unique_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_ptr<A> pA(new A);
@@ -109,4 +109,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
index 53955aaa218..51e2949b6c6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/const_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<const A> pA(new A);
@@ -53,4 +53,6 @@ int main()
         assert(pB.get() == pA.get());
         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
index c27f9503b62..76009b96abd 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/dynamic_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<B> pB(new A);
@@ -53,4 +53,6 @@ int main()
         assert(pA.get() == 0);
         assert(pA.use_count() == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
index ec72834d5cd..9ea544fee01 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cast/static_pointer_cast.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -65,4 +65,6 @@ int main()
         assert(pB.get() == pA.get());
         assert(!pB.owner_before(pA) && !pA.owner_before(pB));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
index 6936744c1ab..98b5bbf0d67 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/cmp_nullptr.pass.cpp
@@ -40,7 +40,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int(1));
     assert(!(p1 == nullptr));
@@ -65,4 +65,6 @@ int main()
     assert(!(nullptr > p2));
     assert( (p2 >= nullptr));
     assert( (nullptr >= p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
index 1257ea65fd8..e25ba611744 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/eq.pass.cpp
@@ -18,7 +18,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     int* ptr1(new int);
     int* ptr2(new int);
@@ -27,4 +27,6 @@ int main()
     const std::shared_ptr<int> p3(ptr2, do_nothing);
     assert(p1 != p2);
     assert(p2 == p3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
index 15e13688b4d..fdef32d518a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.cmp/lt.pass.cpp
@@ -17,7 +17,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     int* ptr1(new int);
     int* ptr2(new int);
@@ -26,4 +26,6 @@ int main()
     const std::shared_ptr<int> p3(ptr2, do_nothing);
     assert((p1 < p2) == (ptr1 < ptr2));
     assert(!(p2 < p3) && !(p3 < p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
index 6558e230dff..282ddd0e0ea 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/auto_ptr.pass.cpp
@@ -43,7 +43,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::auto_ptr<A> ptr(new A);
@@ -94,4 +94,6 @@ int main()
     assert(A::count == 0);
     assert(globalMemCounter.checkOutstandingNewEq(0));
 #endif // !defined(TEST_HAS_NO_EXCEPTIONS) && !defined(DISABLE_NEW_COUNT)
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
index c70e537a9af..247ca0fa924 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/default.pass.cpp
@@ -13,9 +13,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p;
     assert(p.use_count() == 0);
     assert(p.get() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
index a46b31aa5a9..f29dd1cf7ea 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t.pass.cpp
@@ -13,9 +13,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p(nullptr);
     assert(p.use_count() == 0);
     assert(p.get() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
index 9644e4f0f99..ee5861122bf 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     std::shared_ptr<A> p(nullptr, test_deleter<A>(3));
@@ -43,4 +43,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
index bc1d3584e1e..0881e8cf42d 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     std::shared_ptr<A> p(nullptr, test_deleter<A>(3), test_allocator<A>(5));
@@ -81,4 +81,6 @@ int main()
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
index 1948c6860ab..4700df0085c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_allocator_throw.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     try
     {
@@ -43,4 +43,6 @@ int main()
         assert(test_allocator<A>::count == 0);
         assert(test_allocator<A>::alloc_count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
index 075cadf43d6..7d2628d60dc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/nullptr_t_deleter_throw.pass.cpp
@@ -37,7 +37,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     globalMemCounter.throw_after = 0;
     try
@@ -51,4 +51,6 @@ int main()
         assert(test_deleter<A>::count == 0);
         assert(test_deleter<A>::dealloc_count == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
index 67f0ffd2a80..b55d764a6c4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer.pass.cpp
@@ -24,7 +24,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -42,4 +42,6 @@ int main()
     assert(p.get() == ptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
index 120171456be..fd98193826e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -44,4 +44,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
index 79a0bc84a39..0ec18a7aebd 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator.pass.cpp
@@ -28,7 +28,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     {
     A* ptr = new A;
@@ -85,4 +85,6 @@ int main()
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 1);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
index ad020f89fd3..5f2984c7e22 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_allocator_throw.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     try
@@ -44,4 +44,6 @@ int main()
         assert(test_allocator<A>::count == 0);
         assert(test_allocator<A>::alloc_count == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
index 6af99aaf55e..da12e42ca0b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_deleter_throw.pass.cpp
@@ -34,7 +34,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     globalMemCounter.throw_after = 0;
@@ -50,4 +50,6 @@ int main()
         assert(test_deleter<A>::dealloc_count == 1);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
index 95da6f69106..15e776003d9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/pointer_throw.pass.cpp
@@ -33,7 +33,7 @@ struct A
 int A::count = 0;
 
 
-int main()
+int main(int, char**)
 {
     A* ptr = new A;
     assert(A::count == 1);
@@ -48,4 +48,6 @@ int main()
         assert(A::count == 0);
     }
     assert(globalMemCounter.checkOutstandingNewEq(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
index 44a5be4714b..091782f02f3 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -58,4 +58,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
index 3b7279087ff..01a74898f9c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y.pass.cpp
@@ -50,7 +50,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::shared_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::shared_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -93,4 +93,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
index 8d3af186e50..cc86d12dfcf 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_Y_rv.pass.cpp
@@ -54,7 +54,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::shared_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::shared_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -109,4 +109,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
index 06a285cd2ce..83a9a9720dc 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_pointer.pass.cpp
@@ -37,7 +37,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -57,4 +57,6 @@ int main()
     }
     assert(A::count == 0);
     assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
index d9eef4a2388..86797a047e8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/shared_ptr_rv.pass.cpp
@@ -30,7 +30,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> pA(new A);
@@ -73,4 +73,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
index d235a50b9a1..6fd812fca0a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/unique_ptr.pass.cpp
@@ -49,7 +49,7 @@ void fn ( const std::shared_ptr<B> &) { assert (false); }
 template <typename T>
 void assert_deleter ( T * ) { assert(false); }
 
-int main()
+int main(int, char**)
 {
     {
         std::unique_ptr<A> ptr(new A);
@@ -97,4 +97,6 @@ int main()
         std::shared_ptr<int> p2(std::move(p)); // should not call deleter when going out of scope
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
index 117a74aaa57..9174f39be37 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.const/weak_ptr.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
 #ifndef TEST_HAS_NO_EXCEPTIONS
     {
@@ -81,4 +81,6 @@ int main()
     }
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
index 354a23e7015..06c2bba6705 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared.pass.cpp
@@ -51,7 +51,7 @@ private:
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     int i = 67;
@@ -82,4 +82,6 @@ int main()
     assert(p->get_char() == 'f');
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
index 0783b6e7f1c..00f79cc19d2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/allocate_shared_cxx03.pass.cpp
@@ -97,7 +97,7 @@ void test()
     assert(Three::count == 0);
 }
 
-int main()
+int main(int, char**)
 {
     {
     int i = 67;
@@ -114,4 +114,6 @@ int main()
 #if TEST_STD_VER >= 11
     test<min_allocator<void> >();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
index 2535519b9e7..aed060e5790 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.pass.cpp
@@ -73,7 +73,7 @@ void test_pointer_to_function() {
 void test_pointer_to_function() {}
 #endif // _LIBCPP_VERSION
 
-int main()
+int main(int, char**)
 {
     int nc = globalMemCounter.outstanding_new;
     {
@@ -107,4 +107,6 @@ int main()
     }
 #endif
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
index fd5ebdccab3..e17d7424be4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.private.fail.cpp
@@ -22,7 +22,9 @@ private:
    S () {};  // ctor is private
 };
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<S> p = std::make_shared<S>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
index 8ba4a69c3c4..d4d8fb630c9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.protected.fail.cpp
@@ -22,7 +22,9 @@ protected:
    S () {};  // ctor is protected
 };
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<S> p = std::make_shared<S>();  // expected-error-re@memory:* {{static_assert failed{{.*}} "Can't construct object in make_shared"}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
index c50b68f7097..aa038f7475f 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.create/make_shared.volatile.pass.cpp
@@ -52,9 +52,11 @@ void test(const T &t0)
 
 }
 
-int main()
+int main(int, char**)
 {
     test<bool>(true);
     test<int>(3);
     test<double>(5.0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.dest/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
index cf3aac86aec..b09550a6eab 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.io/io.pass.cpp
@@ -18,11 +18,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::shared_ptr<int> p(new int(3));
     std::ostringstream os;
     assert(os.str().empty());
     os << p;
     assert(!os.str().empty());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
index 3943b5892ba..c9df003192b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset.pass.cpp
@@ -38,7 +38,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -58,4 +58,6 @@ int main()
         assert(p.get() == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
index 3e91fa3de56..c3582416584 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer.pass.cpp
@@ -38,7 +38,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -60,4 +60,6 @@ int main()
         assert(p.get() == ptr);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
index 70a2024cce2..e7d457fa139 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -75,4 +75,6 @@ int main()
     assert(A::count == 0);
     assert(test_deleter<A>::count == 0);
     assert(test_deleter<A>::dealloc_count == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
index d4db96826e3..9e2bd101290 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/reset_pointer_deleter_allocator.pass.cpp
@@ -40,7 +40,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<B> p(new B);
@@ -84,4 +84,6 @@ int main()
     assert(test_deleter<A>::dealloc_count == 2);
     assert(test_allocator<A>::count == 0);
     assert(test_allocator<A>::alloc_count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
index a47e67f04a9..a27949ebb80 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.mod/swap.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -100,4 +100,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
index 5f7d6582b6f..77bf3a22e08 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/arrow.pass.cpp
@@ -16,7 +16,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<std::pair<int, int> > p(new std::pair<int, int>(3, 4));
     assert(p->first == 3);
@@ -25,4 +25,6 @@ int main()
     p->second = 6;
     assert(p->first == 5);
     assert(p->second == 6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
index 4b2a495a89b..a6f75533acb 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/dereference.pass.cpp
@@ -15,10 +15,12 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p(new int(32));
     assert(*p == 32);
     *p = 3;
     assert(*p == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
index 4c6790f867c..247deb07bb9 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/op_bool.pass.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     const std::shared_ptr<int> p(new int(32));
@@ -25,4 +25,6 @@ int main()
     const std::shared_ptr<int> p;
     assert(!p);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
index c6ae19911c3..497a53b2144 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_shared_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -26,4 +26,6 @@ int main()
     assert(p1.owner_before(p3) || p3.owner_before(p1));
     assert(p3.owner_before(p1) == p3.owner_before(p2));
     ASSERT_NOEXCEPT(p1.owner_before(p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
index e857aa6a83d..07c7a064420 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/owner_before_weak_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(p1.owner_before(w3) || p3.owner_before(w1));
     assert(p3.owner_before(w1) == p3.owner_before(w2));
     ASSERT_NOEXCEPT(p1.owner_before(w2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
index 14a2fe992f1..dfad3138517 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.obs/unique.pass.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p(new int(32));
     assert(p.unique());
@@ -24,4 +24,6 @@ int main()
     assert(!p.unique());
     }
     assert(p.unique());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
index b40e4705acf..b0bfcae9ae4 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.shared/util.smartptr.shared.spec/swap.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -101,4 +101,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
index 2263eb810cb..f5bdb876b46 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/types.pass.cpp
@@ -19,7 +19,9 @@
 
 struct A;  // purposefully incomplete
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::weak_ptr<A>::element_type, A>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
index c65755d8ea4..b3cc13d72a8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.ownerless/owner_less.pass.cpp
@@ -52,7 +52,7 @@
 
 struct X {};
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -128,4 +128,6 @@ int main()
     assert(s.find(vp) == s.end());
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
index 1362537e030..02f180d3d64 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/shared_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> pA(new A);
@@ -57,4 +57,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
index 739165c3cab..f41c391c4c2 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -74,4 +74,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
index f763dc46395..33b2ddd422a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.assign/weak_ptr_Y.pass.cpp
@@ -39,7 +39,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -74,4 +74,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
index b29623f296a..e5a70abe417 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/default.pass.cpp
@@ -17,8 +17,10 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::weak_ptr<A> p;
     assert(p.use_count() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
index 8aaeab0c904..45be55e66f8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/shared_ptr_Y.pass.cpp
@@ -50,7 +50,7 @@ struct C
 
 int C::count = 0;
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::shared_ptr<A>, std::weak_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::weak_ptr<B>, std::shared_ptr<A> >::value), "");
@@ -91,4 +91,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
index 351b66323db..658b233c41c 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr.pass.cpp
@@ -61,7 +61,7 @@ template <class T>
 void sink (std::weak_ptr<T> &&) {}
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         const std::shared_ptr<A> ps(new A);
@@ -112,4 +112,6 @@ int main()
     assert(B::count == 0);
     assert(A::count == 0);
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
index e155e4faa13..4268fda3aba 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.const/weak_ptr_Y.pass.cpp
@@ -54,7 +54,7 @@ int C::count = 0;
 template <class T>
 std::weak_ptr<T> source (std::shared_ptr<T> p) { return std::weak_ptr<T>(p); }
 
-int main()
+int main(int, char**)
 {
     static_assert(( std::is_convertible<std::weak_ptr<A>, std::weak_ptr<B> >::value), "");
     static_assert((!std::is_convertible<std::weak_ptr<B>, std::weak_ptr<A> >::value), "");
@@ -104,4 +104,6 @@ int main()
     }
     assert(B::count == 0);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.dest/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
index 7c3bcb6c641..eae249ca1a5 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/reset.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::shared_ptr<A> p1(new A);
@@ -37,4 +37,6 @@ int main()
         assert(p1.use_count() == 1);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
index 38b1dee093a..76703d0ddd7 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.mod/swap.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -45,4 +45,6 @@ int main()
         }
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
index f2fccb5589d..5fb2dd4f95b 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/expired.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::weak_ptr<A> wp;
@@ -42,4 +42,6 @@ int main()
         assert(wp.use_count() == 0);
         assert(wp.expired() == (wp.use_count() == 0));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
index 883de740cce..50ff84318ef 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/lock.pass.cpp
@@ -26,7 +26,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         std::weak_ptr<A> wp;
@@ -54,4 +54,6 @@ int main()
         assert(A::count == 0);
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
index c916a890740..2df6d6a0e32 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/not_less_than.fail.cpp
@@ -15,7 +15,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2(new int);
@@ -23,4 +23,6 @@ int main()
     const std::weak_ptr<int> w2(p2);
 
     bool b = w1 < w2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
index d8483d9b65e..4d26f5f2b33 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_shared_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(w1.owner_before(p3) || w3.owner_before(p1));
     assert(w3.owner_before(p1) == w3.owner_before(p2));
     ASSERT_NOEXCEPT(w1.owner_before(p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
index b323da7d503..39993cd8f6a 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.obs/owner_before_weak_ptr.pass.cpp
@@ -16,7 +16,7 @@
 #include <cassert>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     const std::shared_ptr<int> p1(new int);
     const std::shared_ptr<int> p2 = p1;
@@ -29,4 +29,6 @@ int main()
     assert(w1.owner_before(w3) || w3.owner_before(w1));
     assert(w3.owner_before(w1) == w3.owner_before(w2));
     ASSERT_NOEXCEPT(w1.owner_before(w2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
index e13d5aeaf63..53bc3eb9cd8 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weak/util.smartptr.weak.spec/swap.pass.cpp
@@ -27,7 +27,7 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
         A* ptr1 = new A;
@@ -46,4 +46,6 @@ int main()
         }
     }
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
index a85120ae05f..f3e26dee54e 100644
--- a/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
+++ b/libcxx/test/std/utilities/memory/util.smartptr/util.smartptr.weakptr/bad_weak_ptr.pass.cpp
@@ -20,11 +20,13 @@
 #include <cassert>
 #include <cstring>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_base_of<std::exception, std::bad_weak_ptr>::value), "");
     std::bad_weak_ptr e;
     std::bad_weak_ptr e2 = e;
     e2 = e;
     assert(std::strcmp(e.what(), "bad_weak_ptr") == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp b/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
index b9037f52704..917f8b919fa 100644
--- a/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.help/bool_constant.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER > 14
     typedef std::bool_constant<true> _t;
@@ -30,4 +30,6 @@ int main()
     static_assert((std::is_same<_f::type, _f>::value), "");
     static_assert((_f() == false), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp b/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
index 89d64875095..f312acad657 100644
--- a/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.help/integral_constant.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::integral_constant<int, 5> _5;
     static_assert(_5::value == 5, "");
@@ -47,4 +47,6 @@ int main()
     std::true_type t1;
     std::true_type t2 = t1;
     assert(t2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
index 0b9a0362130..e37769576d2 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/conjunction.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert ( std::conjunction<>::value, "" );
     static_assert ( std::conjunction<std::true_type >::value, "" );
@@ -62,4 +62,6 @@ int main()
 
     static_assert ( std::conjunction_v<True >, "" );
     static_assert (!std::conjunction_v<False>, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
index 00a1b306d61..baaed6f03ce 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/disjunction.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::disjunction<>::value, "" );
     static_assert ( std::disjunction<std::true_type >::value, "" );
@@ -62,4 +62,6 @@ int main()
 
     static_assert ( std::disjunction_v<True >, "" );
     static_assert (!std::disjunction_v<False>, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp b/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
index d399a5c84e6..88ca693d31b 100644
--- a/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.logical/negation.pass.cpp
@@ -19,7 +19,7 @@
 struct True  { static constexpr bool value = true; };
 struct False { static constexpr bool value = false; };
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::negation<std::true_type >::value, "" );
     static_assert ( std::negation<std::false_type>::value, "" );
@@ -35,4 +35,6 @@ int main()
 
     static_assert ( std::negation<std::negation<std::true_type >>::value, "" );
     static_assert (!std::negation<std::negation<std::false_type>>::value, "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
index c2b84b35427..ec27581a4f9 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_base_of.pass.cpp
@@ -40,7 +40,7 @@ struct B1 : B {};
 struct B2 : B {};
 struct D : private B1, private B2 {};
 
-int main()
+int main(int, char**)
 {
     test_is_base_of<B, D>();
     test_is_base_of<B1, D>();
@@ -53,4 +53,6 @@ int main()
     test_is_not_base_of<B&, D&>();
     test_is_not_base_of<B[3], D[3]>();
     test_is_not_base_of<int, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
index faffaf6b3d6..b1722b0fcec 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_convertible.pass.cpp
@@ -60,7 +60,7 @@ class CannotInstantiate {
   enum { X = T::ThisExpressionWillBlowUp };
 };
 
-int main()
+int main(int, char**)
 {
     // void
     test_is_convertible<void,void> ();
@@ -259,4 +259,6 @@ int main()
     // Ensure that CannotInstantiate is not instantiated by is_convertible when it is not needed.
     // For example CannotInstantiate is instatiated as a part of ADL lookup for arguments of type CannotInstantiate*.
     static_assert((std::is_convertible<CannotInstantiate<int>*, CannotInstantiate<int>*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
index dab17974bb8..fa0c0c82e8a 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_invocable.pass.cpp
@@ -46,7 +46,7 @@ struct Sink {
   void operator()(Args&&...) const {}
 };
 
-int main() {
+int main(int, char**) {
   using AbominableFunc = void(...) const;
 
   //  Non-callable things
@@ -241,4 +241,5 @@ int main() {
   static_assert(std::is_invocable_r_v<void, Fn>, "");
   static_assert(!std::is_invocable_r_v<int, Fn>, "");
 }
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
index f21e99b02d0..baf64c12f9e 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_nothrow_invocable.pass.cpp
@@ -80,7 +80,7 @@ void test_noexcept_function_pointers() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   using AbominableFunc = void(...) const noexcept;
   //  Non-callable things
   {
@@ -212,4 +212,6 @@ int main() {
     static_assert(!std::is_nothrow_invocable_r_v<int, Fn, int>, "");
   }
   test_noexcept_function_pointers();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp b/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
index 63458055008..739713bf4c2 100644
--- a/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rel/is_same.pass.cpp
@@ -56,7 +56,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_same<int, int>();
     test_is_same<void, void>();
@@ -69,4 +69,6 @@ int main()
     test_is_not_same<Class, int*>();
     test_is_not_same<int*, int&>();
     test_is_not_same<int&, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.rqmts/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
index 62699fed46e..a887d52bbc0 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_all_extents.pass.cpp
@@ -25,7 +25,7 @@ void test_remove_all_extents()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_all_extents<int, int> ();
     test_remove_all_extents<const Enum, const Enum> ();
@@ -39,4 +39,6 @@ int main()
     test_remove_all_extents<const int[2][3], const int> ();
     test_remove_all_extents<int[1][2][3], int> ();
     test_remove_all_extents<const int[1][2][3], const int> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
index 1c0f9884817..a0b19d6a64a 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.arr/remove_extent.pass.cpp
@@ -26,7 +26,7 @@ void test_remove_extent()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_remove_extent<int, int> ();
     test_remove_extent<const Enum, const Enum> ();
@@ -40,4 +40,6 @@ int main()
     test_remove_extent<const int[2][3], const int[3]> ();
     test_remove_extent<int[1][2][3], int[2][3]> ();
     test_remove_extent<const int[1][2][3], const int[2][3]> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
index c7fb61232b3..edde6565744 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_const.pass.cpp
@@ -32,7 +32,7 @@ void test_add_const()
     test_add_const_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_const<void>();
     test_add_const<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_const<const int&>();
     test_add_const<int*>();
     test_add_const<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
index 0662c9dd400..5621bbf4263 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_cv.pass.cpp
@@ -32,7 +32,7 @@ void test_add_cv()
     test_add_cv_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_cv<void>();
     test_add_cv<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_cv<const int&>();
     test_add_cv<int*>();
     test_add_cv<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
index 476a780a423..6dfaa60f894 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/add_volatile.pass.cpp
@@ -32,7 +32,7 @@ void test_add_volatile()
     test_add_volatile_imp<const volatile T, const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_add_volatile<void>();
     test_add_volatile<int>();
@@ -41,4 +41,6 @@ int main()
     test_add_volatile<const int&>();
     test_add_volatile<int*>();
     test_add_volatile<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
index d53d6f805f9..3c927e7c92e 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_const.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_const()
     test_remove_const_imp<const volatile T, volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_const<void>();
     test_remove_const<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_const<const int&>();
     test_remove_const<int*>();
     test_remove_const<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
index 569b9642d35..2dc8d26e0e3 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_cv.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_cv()
     test_remove_cv_imp<const volatile T, T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_cv<void>();
     test_remove_cv<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_cv<const int&>();
     test_remove_cv<int*>();
     test_remove_cv<const int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
index 358d2fa8bfd..fb45d94395e 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.cv/remove_volatile.pass.cpp
@@ -32,7 +32,7 @@ void test_remove_volatile()
     test_remove_volatile_imp<const volatile T, const T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_volatile<void>();
     test_remove_volatile<int>();
@@ -41,4 +41,6 @@ int main()
     test_remove_volatile<const int&>();
     test_remove_volatile<int*>();
     test_remove_volatile<volatile int*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
index 08c0b8bb162..3e80402e814 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_storage.pass.cpp
@@ -17,7 +17,7 @@
 #include <cstddef>       // for std::max_align_t
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::aligned_storage<10, 1 >::type T1;
@@ -285,4 +285,6 @@ int main()
     static_assert(std::alignment_of<T1>::value == 8, "");
     static_assert(sizeof(T1) == 16, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
index 2564f112005..cf9fe632dd3 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.fail.cpp
@@ -16,7 +16,9 @@
 
 class A; // Incomplete
 
-int main()
+int main(int, char**)
 {
     typedef std::aligned_union<10, A>::type T1;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
index 800a0074cb9..789fd12a9ff 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/aligned_union.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::aligned_union<10, char >::type T1;
@@ -111,4 +111,6 @@ int main()
     static_assert(std::alignment_of<T1>::value == 4, "");
     static_assert(sizeof(T1) == 4, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
index 70d2ddf095a..f96603b30b6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/common_type.pass.cpp
@@ -234,7 +234,7 @@ static_assert(is_same<typename result_of<PMD(const S*)>::type, const char&>::val
 } // namespace note_b_example
 #endif // TEST_STD_VER >= 11
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::common_type<int>::type, int>::value), "");
     static_assert((std::is_same<std::common_type<char>::type, char>::value), "");
@@ -307,4 +307,6 @@ int main()
     static_assert((std::is_same<std::common_type<const int, int>::type,       int>::value), "");
     static_assert((std::is_same<std::common_type<int, const int>::type,       int>::value), "");
     static_assert((std::is_same<std::common_type<const int, const int>::type, int>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
index b408dfb2c2c..288376ac93c 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/conditional.pass.cpp
@@ -14,7 +14,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::conditional<true, char, int>::type, char>::value), "");
     static_assert((std::is_same<std::conditional<false, char, int>::type, int>::value), "");
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<std::conditional_t<true, char, int>, char>::value), "");
     static_assert((std::is_same<std::conditional_t<false, char, int>, int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
index a6f85e921b8..94d9720399f 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/decay.pass.cpp
@@ -23,7 +23,7 @@ void test_decay()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_decay<void, void>();
     test_decay<int, int>();
@@ -38,4 +38,6 @@ int main()
     test_decay<int(int)  &, int(int)  &>();
     test_decay<int(int) &&, int(int) &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
index c7b0763e1d8..c033d1aef26 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.fail.cpp
@@ -12,7 +12,9 @@
 
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::enable_if<false>::type A;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
index bb107d90ad9..c02c6efdb2d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if.pass.cpp
@@ -14,7 +14,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::enable_if<true>::type, void>::value), "");
     static_assert((std::is_same<std::enable_if<true, int>::type, int>::value), "");
@@ -22,4 +22,6 @@ int main()
     static_assert((std::is_same<std::enable_if_t<true>, void>::value), "");
     static_assert((std::is_same<std::enable_if_t<true, int>, int>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
index 70aa3e2121f..79382d35993 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/enable_if2.fail.cpp
@@ -13,7 +13,9 @@
 
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::enable_if_t<false> A;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
index e67cab8e4a8..e6a01a77ac5 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/remove_cvref.pass.cpp
@@ -23,7 +23,7 @@ void test_remove_cvref()
     static_assert((std::is_same<         std::remove_cvref_t<T>,     U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_cvref<void, void>();
     test_remove_cvref<int, int>();
@@ -48,4 +48,6 @@ int main()
     test_remove_cvref<int(int) volatile, int(int) volatile>();
     test_remove_cvref<int(int)  &, int(int)  &>();
     test_remove_cvref<int(int) &&, int(int) &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
index 313691f3228..34dd6d8ea03 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of.pass.cpp
@@ -92,7 +92,7 @@ void test_no_result()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     typedef NotDerived ND;
     { // functor object
@@ -366,4 +366,6 @@ int main()
 #endif
     test_no_result<PMD(ND&)>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
index 55fef6a406e..4c020d3da77 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/result_of11.pass.cpp
@@ -55,7 +55,7 @@ void test_result_of_imp()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef char F::*PMD;
@@ -168,4 +168,6 @@ int main()
     test_result_of_imp<int (F::* (std::unique_ptr<const F> ))       () const, int>();
     }
     test_result_of_imp<decltype(&wat::foo)(wat), void>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
index 2946e17f55d..7e90c3df9c6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/type_identity.pass.cpp
@@ -22,7 +22,7 @@ void test_type_identity()
     static_assert((std::is_same<         std::type_identity_t<T>,     T>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test_type_identity<void>();
     test_type_identity<int>();
@@ -36,4 +36,6 @@ int main()
     test_type_identity<int(int) volatile>();
     test_type_identity<int(int)  &>();
     test_type_identity<int(int) &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
index ed1bdc44c69..be1c739ee82 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.other/underlying_type.pass.cpp
@@ -27,7 +27,7 @@ enum E { V = INT_MIN };
 enum F { W = UINT_MAX };
 #endif // TEST_UNSIGNED_UNDERLYING_TYPE
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::underlying_type<E>::type, int>::value),
                   "E has the wrong underlying type");
@@ -52,4 +52,6 @@ int main()
     static_assert((std::is_same<std::underlying_type_t<G>, char>::value), "");
 #endif // TEST_STD_VER > 11
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
index ec4e270be47..22c0b79d6f2 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/add_pointer.pass.cpp
@@ -45,7 +45,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_pointer<void, void*>();
     test_add_pointer<int, int*>();
@@ -76,4 +76,6 @@ int main()
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
index 1f62b141251..ba7cceb2968 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ptr/remove_pointer.pass.cpp
@@ -22,7 +22,7 @@ void test_remove_pointer()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_pointer<void, void>();
     test_remove_pointer<int, int>();
@@ -40,4 +40,6 @@ int main()
     test_remove_pointer<int(*)[3], int[3]>();
     test_remove_pointer<int*&, int*&>();
     test_remove_pointer<const int*&, const int*&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
index 68d8aef35e1..dadcafca6b0 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_lvalue_ref.pass.cpp
@@ -44,7 +44,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_lvalue_reference<void, void>();
     test_add_lvalue_reference<int, int&>();
@@ -75,4 +75,6 @@ int main()
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
index c13a6236631..34c6cd3dd6d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/add_rvalue_ref.pass.cpp
@@ -46,7 +46,7 @@ void test_function1()
 
 struct Foo {};
 
-int main()
+int main(int, char**)
 {
     test_add_rvalue_reference<void, void>();
     test_add_rvalue_reference<int, int&&>();
@@ -73,4 +73,6 @@ int main()
     test_function0<void (Foo::*)() &&>();
     test_function0<void (Foo::*)() const &>();
     test_function0<void (Foo::*)() const &&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
index 1cecd51e28d..5612ba678ab 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.ref/remove_ref.pass.cpp
@@ -22,7 +22,7 @@ void test_remove_reference()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_remove_reference<void, void>();
     test_remove_reference<int, int>();
@@ -43,4 +43,6 @@ int main()
     test_remove_reference<int*&&, int*>();
     test_remove_reference<const int*&&, const int*>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
index b962782d03d..fa6ce8e3e4d 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_signed.pass.cpp
@@ -42,7 +42,7 @@ void test_make_signed()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_make_signed< signed char, signed char >();
     test_make_signed< unsigned char, signed char >();
@@ -66,4 +66,6 @@ int main()
     test_make_signed< HugeEnum, __int128_t >();
 # endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
index 606fdf426a9..cf5404f8c90 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/meta.trans.sign/make_unsigned.pass.cpp
@@ -42,7 +42,7 @@ void test_make_unsigned()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_make_unsigned<signed char, unsigned char> ();
     test_make_unsigned<unsigned char, unsigned char> ();
@@ -67,4 +67,6 @@ int main()
     test_make_unsigned<HugeEnum, __uint128_t>();
 # endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.trans/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp b/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
index 65ba3019261..52924b357b8 100644
--- a/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.type.synop/endian.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main() {
+int main(int, char**) {
     static_assert(std::is_enum<std::endian>::value, "");
 
 // Check that E is a scoped enum by checking for conversions.
@@ -43,4 +43,6 @@ int main() {
 
     assert ((c[0] == 1) == (std::endian::native == std::endian::big));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.type.synop/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
index 903098415be..43cc5bfcefc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/alignment_of.pass.cpp
@@ -39,7 +39,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_alignment_of<int&, 4>();
     test_alignment_of<Class, 1>();
@@ -57,4 +57,6 @@ int main()
     test_alignment_of<bool, 1>();
 #endif
     test_alignment_of<unsigned, 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
index bfd36533ebb..927ce1373cc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/extent.pass.cpp
@@ -50,7 +50,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_extent<void, 0>();
     test_extent<int&, 0>();
@@ -70,4 +70,6 @@ int main()
     test_extent1<int[2], 0>();
     test_extent1<int[2][4], 4>();
     test_extent1<int[][4], 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
index 74a3637a475..6c2eecb86db 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/rank.pass.cpp
@@ -35,7 +35,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_rank<void, 0>();
     test_rank<int&, 0>();
@@ -50,4 +50,6 @@ int main()
     test_rank<char[3], 1>();
     test_rank<char[][3], 2>();
     test_rank<char[][4][3], 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
index af46f4726fc..652eddaa88a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t.pass.cpp
@@ -45,7 +45,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     static_assert( std::is_same<void, std::void_t<>>::value, "");
 
@@ -64,4 +64,6 @@ int main()
     test2<void *, int&>();
 
     static_assert( std::is_same<void, std::void_t<int, double const &, Class, volatile int[], void>>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
index 25b8d715aed..90514eaaebf 100644
--- a/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary.prop.query/void_t_feature_test_macro.pass.cpp
@@ -27,9 +27,11 @@
 # endif
 #endif
 
-int main()
+int main(int, char**)
 {
 #if defined(__cpp_lib_void_t)
   static_assert(std::is_same_v<std::void_t<int>, void>, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
index 1e2dc42ae21..9f3d8f558d1 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/array.pass.cpp
@@ -48,7 +48,7 @@ typedef const char const_array[3];
 typedef char incomplete_array[];
 struct Incomplete;
 
-int main()
+int main(int, char**)
 {
     test_array<array>();
     test_array<const_array>();
@@ -57,4 +57,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_array<Incomplete>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
index 93bf9efb42f..3dd696932bc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/class.pass.cpp
@@ -49,11 +49,13 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_class<Class>();
     test_class<incomplete_type>();
 
 //  LWG#2582
     static_assert( std::is_class<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
index 95f71b68a2e..5fa8499303c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/enum.pass.cpp
@@ -46,10 +46,12 @@ void test_enum()
 enum Enum {zero, one};
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_enum<Enum>();
 
 //  LWG#2582
     static_assert(!std::is_enum<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
index c4cf7153b44..1f7556c7a01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/floating_point.pass.cpp
@@ -45,7 +45,7 @@ void test_floating_point()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_floating_point<float>();
     test_floating_point<double>();
@@ -53,4 +53,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_floating_point<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
index 19ad3e92b84..d7453be469c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/function.pass.cpp
@@ -66,7 +66,7 @@ void test()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     TEST_REGULAR( void () );
     TEST_REGULAR( void (int) );
@@ -89,4 +89,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_function<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
index 74977e4b160..df66316b9c8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/integral.pass.cpp
@@ -45,7 +45,7 @@ void test_integral()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_integral<bool>();
     test_integral<char>();
@@ -67,4 +67,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_integral<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
index 8611daa15f1..3205819911c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_array.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_array<char[3]>();
     test_is_array<char[]>();
@@ -90,4 +90,6 @@ int main()
     test_is_not_array<bit_zero>();
     test_is_not_array<NotEmpty>();
     test_is_not_array<incomplete_type>();  //  LWG#2582
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
index 6eda248f7c5..def798b779b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_class.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_class<Empty>();
     test_is_class<bit_zero>();
@@ -96,4 +96,6 @@ int main()
     test_is_not_class<Enum>();
     test_is_not_class<Union>();
     test_is_not_class<FunctionPtr>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
index 0261581f6bf..7d4b67fd872 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_enum.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_enum<Enum>();
 
@@ -91,4 +91,6 @@ int main()
     test_is_not_enum<Abstract>();
     test_is_not_enum<FunctionPtr>();
     test_is_not_enum<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
index 78e581a0c4f..e628451dc7d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_floating_point.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_floating_point<float>();
     test_is_floating_point<double>();
@@ -99,4 +99,6 @@ int main()
     test_is_not_floating_point<Enum>();
     test_is_not_floating_point<FunctionPtr>();
     test_is_not_floating_point<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
index 0f2304fe7cd..b582499cb8b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_function.pass.cpp
@@ -74,7 +74,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_function<void(void)>();
     test_is_function<int(int)>();
@@ -105,4 +105,6 @@ int main()
   test_is_function<void() noexcept>();
   test_is_function<void() const && noexcept>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
index ede74445e28..216df3b5611 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_integral.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_integral<short>();
     test_is_integral<unsigned short>();
@@ -105,4 +105,6 @@ int main()
     test_is_not_integral<NotEmpty>();
     test_is_not_integral<Abstract>();
     test_is_not_integral<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
index fe045a29735..ed32cd9b999 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_lvalue_reference.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_lvalue_reference<int&>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_lvalue_reference<NotEmpty>();
     test_is_not_lvalue_reference<Abstract>();
     test_is_not_lvalue_reference<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
index 7e20b58fc01..95a8b558578 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_object_pointer.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_member_object_pointer<int Abstract::*>();
     test_is_member_object_pointer<double NotEmpty::*>();
@@ -95,4 +95,6 @@ int main()
     test_is_not_member_object_pointer<NotEmpty>();
     test_is_not_member_object_pointer<Abstract>();
     test_is_not_member_object_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
index 0a1b95354f5..cf46c7261db 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_member_pointer.pass.cpp
@@ -71,7 +71,7 @@ struct incomplete_type;
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_member_pointer<int Abstract::*>();
     test_is_member_pointer<double NotEmpty::*>();
@@ -102,4 +102,6 @@ int main()
   test_is_member_pointer<int (Empty::*)(int, long, long) const noexcept>();
   test_is_member_pointer<int (Empty::*)() & noexcept>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
index 762c21406d3..7ad765d8bbd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_null_pointer.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_null_pointer<std::nullptr_t>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_null_pointer<NotEmpty>();
     test_is_not_null_pointer<Abstract>();
     test_is_not_null_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
index 9fa33b93c53..18609b812ea 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_pointer.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_pointer<void*>();
     test_is_pointer<int*>();
@@ -92,4 +92,6 @@ int main()
     test_is_not_pointer<NotEmpty>();
     test_is_not_pointer<Abstract>();
     test_is_not_pointer<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
index 92e86713cc8..d17ed5feeff 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_rvalue_reference.pass.cpp
@@ -72,7 +72,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_rvalue_reference<int&&>();
 
@@ -93,4 +93,6 @@ int main()
     test_is_not_rvalue_reference<NotEmpty>();
     test_is_not_rvalue_reference<Abstract>();
     test_is_not_rvalue_reference<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
index 0fc3c4361fe..a86147a9acd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_union.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_union<Union>();
 
@@ -91,4 +91,6 @@ int main()
     test_is_not_union<NotEmpty>();
     test_is_not_union<Abstract>();
     test_is_not_union<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
index 0bfeaddee83..ccbca975398 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/is_void.pass.cpp
@@ -70,7 +70,7 @@ struct incomplete_type;
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
     test_is_void<void>();
 
@@ -90,4 +90,6 @@ int main()
     test_is_not_void<Enum>();
     test_is_not_void<FunctionPtr>();
     test_is_not_void<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
index b4f010749e8..1c431edfa5f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/lvalue_ref.pass.cpp
@@ -37,11 +37,13 @@ void test_lvalue_ref()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_lvalue_ref<int&>();
     test_lvalue_ref<const int&>();
 
 //  LWG#2582
     static_assert(!std::is_lvalue_reference<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
index 345195e0e36..fdbfd903940 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer.pass.cpp
@@ -52,7 +52,7 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
   test_member_function_pointer<void (Class::*)()>();
   test_member_function_pointer<void (Class::*)(int)>();
@@ -225,4 +225,6 @@ int main()
 
 //  LWG#2582
   static_assert(!std::is_member_function_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
index 672a90a6f76..916c580d591 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_function_pointer_no_variadics.pass.cpp
@@ -51,7 +51,7 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_member_function_pointer<void (Class::*)()>();
     test_member_function_pointer<void (Class::*)(int)>();
@@ -79,4 +79,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_member_function_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
index 2f77553fd58..b22e59e379d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/member_object_pointer.pass.cpp
@@ -49,10 +49,12 @@ class Class
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_member_object_pointer<int Class::*>();
 
 //  LWG#2582
     static_assert(!std::is_member_object_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
index 759eee6681a..993b32fdf01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/nullptr.pass.cpp
@@ -46,13 +46,16 @@ void test_nullptr()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_nullptr<std::nullptr_t>();
 
 //  LWG#2582
     static_assert(!std::is_null_pointer<incomplete_type>::value, "");
+    return 0;
 }
 #else
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #endif
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
index 68964f52616..68f4186db56 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/pointer.pass.cpp
@@ -46,7 +46,7 @@ void test_pointer()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_pointer<void*>();
     test_pointer<int*>();
@@ -55,4 +55,6 @@ int main()
 
 //  LWG#2582
     static_assert(!std::is_pointer<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
index cf0b246c6a1..e40a2a01443 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/rvalue_ref.pass.cpp
@@ -38,11 +38,13 @@ void test_rvalue_ref()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_rvalue_ref<int&&>();
     test_rvalue_ref<const int&&>();
 
 //  LWG#2582
     static_assert(!std::is_rvalue_reference<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
index 683eed65a28..a840f5bb295 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/union.pass.cpp
@@ -51,10 +51,12 @@ union Union
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_union<Union>();
 
 //  LWG#2582
     static_assert(!std::is_union<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
index 047de20045b..d9defa528be 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.cat/void.pass.cpp
@@ -45,10 +45,12 @@ void test_void()
 
 struct incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_void<void>();
 
 //  LWG#2582
     static_assert(!std::is_void<incomplete_type>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
index b0ced4a9ce4..487e14446c3 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/array.pass.cpp
@@ -39,10 +39,12 @@ typedef char incomplete_array[];
 
 class incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_array<array>();
     test_array<const_array>();
     test_array<incomplete_array>();
     test_array<incomplete_type[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
index bff535c9ade..bc072198f2e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/class.pass.cpp
@@ -39,8 +39,10 @@ class Class
 
 class incomplete_type;
 
-int main()
+int main(int, char**)
 {
     test_class<Class>();
     test_class<incomplete_type>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
index 33807bc4d07..71c74f2ba04 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/enum.pass.cpp
@@ -35,7 +35,9 @@ void test_enum()
 
 enum Enum {zero, one};
 
-int main()
+int main(int, char**)
 {
     test_enum<Enum>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
index 1a1eaee321c..957473c2a91 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/floating_point.pass.cpp
@@ -33,9 +33,11 @@ void test_floating_point()
     test_floating_point_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_floating_point<float>();
     test_floating_point<double>();
     test_floating_point<long double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
index 193cf688fe2..c27b1237ebf 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/function.pass.cpp
@@ -33,10 +33,12 @@ void test_function()
     test_function_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_function<void ()>();
     test_function<void (int)>();
     test_function<int (double)>();
     test_function<int (double, char)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
index d349b75f7be..cac606a516e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/integral.pass.cpp
@@ -33,7 +33,7 @@ void test_integral()
     test_integral_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_integral<bool>();
     test_integral<char>();
@@ -52,4 +52,6 @@ int main()
     test_integral<__int128_t>();
     test_integral<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
index ff0ff7a34c8..683e885e288 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_arithmetic.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_arithmetic<short>();
     test_is_arithmetic<unsigned short>();
@@ -103,4 +103,6 @@ int main()
     test_is_not_arithmetic<bit_zero>();
     test_is_not_arithmetic<NotEmpty>();
     test_is_not_arithmetic<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
index a0d03dd6e51..4d789066d6e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_compound.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_compound<char[3]>();
     test_is_compound<char[]>();
@@ -94,4 +94,6 @@ int main()
     test_is_not_compound<void>();
     test_is_not_compound<int>();
     test_is_not_compound<double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
index 343b1291a0f..b1a38360297 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_fundamental.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_fundamental<std::nullptr_t>();
     test_is_fundamental<void>();
@@ -111,4 +111,6 @@ int main()
     test_is_not_fundamental<Enum>();
     test_is_not_fundamental<NotEmpty>();
     test_is_not_fundamental<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
index e5486f73e9e..82f0ae9aa47 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_member_pointer.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 //  Arithmetic types (3.9.1), enumeration types, pointer types, pointer to member types (3.9.2),
 //    std::nullptr_t, and cv-qualified versions of these types (3.9.3)
@@ -101,4 +101,6 @@ int main()
     test_is_not_member_pointer<int(int)>();
     test_is_not_member_pointer<Enum>();
     test_is_not_member_pointer<FunctionPtr>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
index 8ec4a6d0fd9..8a6f6d84cfc 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_object.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 // An object type is a (possibly cv-qualified) type that is not a function type,
 // not a reference type, and not a void type.
@@ -99,4 +99,6 @@ int main()
     test_is_not_object<int&>();
     test_is_not_object<int&&>();
     test_is_not_object<int(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
index a511daf3522..bb8a2d62ca9 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_reference.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
     test_is_reference<int&>();
 #if TEST_STD_VER >= 11
@@ -100,4 +100,6 @@ int main()
     test_is_not_reference<int Empty::*>();
     test_is_not_reference<void (Empty::*)(int)>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
index c20f1e8ef5a..804c6848eab 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/is_scalar.pass.cpp
@@ -72,7 +72,7 @@ enum Enum {zero, one};
 typedef void (*FunctionPtr)();
 
 
-int main()
+int main(int, char**)
 {
 //  Arithmetic types (3.9.1), enumeration types, pointer types, pointer to member types (3.9.2),
 //    std::nullptr_t, and cv-qualified versions of these types (3.9.3)
@@ -110,4 +110,6 @@ int main()
     test_is_not_scalar<NotEmpty>();
     test_is_not_scalar<Abstract>();
     test_is_not_scalar<int(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
index 0ce0423f646..44027dadb26 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/lvalue_ref.pass.cpp
@@ -24,8 +24,10 @@ void test_lvalue_ref()
     static_assert(!std::is_member_pointer<T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test_lvalue_ref<int&>();
     test_lvalue_ref<const int&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
index cc75ef9666a..fda2e81818a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_function_pointer.pass.cpp
@@ -37,9 +37,11 @@ class Class
 {
 };
 
-int main()
+int main(int, char**)
 {
     test_member_function_pointer<void (Class::*)()>();
     test_member_function_pointer<void (Class::*)(int)>();
     test_member_function_pointer<void (Class::*)(int, char)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
index ea130274211..3e8117b6a01 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/member_object_pointer.pass.cpp
@@ -37,7 +37,9 @@ class Class
 {
 };
 
-int main()
+int main(int, char**)
 {
     test_member_object_pointer<int Class::*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
index 61ae96e5b35..f5677b95b67 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/pointer.pass.cpp
@@ -33,10 +33,12 @@ void test_pointer()
     test_pointer_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_pointer<void*>();
     test_pointer<int*>();
     test_pointer<const int*>();
     test_pointer<void (*)(int)>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
index 63180a00807..341b9462692 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/rvalue_ref.pass.cpp
@@ -26,8 +26,10 @@ void test_rvalue_ref()
     static_assert(!std::is_member_pointer<T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test_rvalue_ref<int&&>();
     test_rvalue_ref<const int&&>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
index d30354d1a25..fb48a70f35f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/union.pass.cpp
@@ -39,7 +39,9 @@ union Union
     double __;
 };
 
-int main()
+int main(int, char**)
 {
     test_union<Union>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
index 3559d7b8311..657f72774f4 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.comp/void.pass.cpp
@@ -33,7 +33,9 @@ void test_void()
     test_void_imp<const volatile T>();
 }
 
-int main()
+int main(int, char**)
 {
     test_void<void>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
index d778526b540..e6f70123b2c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_unique_object_representations.pass.cpp
@@ -80,7 +80,7 @@ struct B
 };
 
 
-int main()
+int main(int, char**)
 {
     test_has_not_has_unique_object_representations<void>();
     test_has_not_has_unique_object_representations<Empty>();
@@ -102,4 +102,6 @@ int main()
     test_has_unique_object_representations<char[3]>();
     test_has_unique_object_representations<char[]>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
index 9ee9bf163ba..57c1027c3ba 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/has_virtual_destructor.pass.cpp
@@ -70,7 +70,7 @@ struct A
     ~A();
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_virtual_destructor<void>();
     test_has_not_virtual_destructor<A>();
@@ -87,4 +87,6 @@ int main()
 
     test_has_virtual_destructor<Abstract>();
     test_has_virtual_destructor<NotEmpty>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
index cbc0317900d..ee6a12e4bd8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_abstract.pass.cpp
@@ -72,7 +72,7 @@ struct AbstractTemplate {
 template <>
 struct AbstractTemplate<double> {};
 
-int main()
+int main(int, char**)
 {
     test_is_not_abstract<void>();
     test_is_not_abstract<int&>();
@@ -90,4 +90,6 @@ int main()
     test_is_abstract<Abstract>();
     test_is_abstract<AbstractTemplate<int> >();
     test_is_not_abstract<AbstractTemplate<double> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
index a8f19fd100e..843231f4605 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_aggregate.pass.cpp
@@ -56,7 +56,7 @@ private:
 struct Union { int x; void* y; };
 
 
-int main ()
+int main(int, char**)
 {
   {
     test_false<void>();
@@ -75,4 +75,6 @@ int main ()
     test_true<Aggregate[42][101]>();
     test_true<Union>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
index eb98ddb547b..8e5e2cc6e04 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_assignable.pass.cpp
@@ -58,7 +58,7 @@ struct E
 template <typename T>
 struct X { T t; };
 
-int main()
+int main(int, char**)
 {
     test_is_assignable<int&, int&> ();
     test_is_assignable<int&, int> ();
@@ -79,4 +79,6 @@ int main()
 
 //  pointer to incomplete template type
     test_is_assignable<X<D>*&, X<D>*> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
index fdbdfbd596c..0af73cf7e0c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_const.pass.cpp
@@ -30,7 +30,7 @@ void test_is_const()
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_const<void>();
     test_is_const<int>();
@@ -44,4 +44,6 @@ int main()
 
     static_assert(!std::is_const<int&>::value, "");
     static_assert(!std::is_const<const int&>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
index f78319aff8d..a5b723c0e59 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_constructible.pass.cpp
@@ -147,7 +147,7 @@ static constexpr bool clang_disallows_valid_static_cast_bug =
 #endif
 
 
-int main()
+int main(int, char**)
 {
     typedef Base B;
     typedef Derived D;
@@ -301,4 +301,6 @@ int main()
     test_is_not_constructible<void() &&> ();
 #endif
 #endif // TEST_STD_VER >= 11
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
index 24719bfb89b..3f10907a4aa 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_assignable.pass.cpp
@@ -63,7 +63,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_copy_assignable<int> ();
     test_is_copy_assignable<int&> ();
@@ -81,4 +81,6 @@ int main()
 #endif
     test_is_not_copy_assignable<void> ();
     test_is_not_copy_assignable<C> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
index 457270a8925..f64c40e862b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_copy_constructible.pass.cpp
@@ -70,7 +70,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_copy_constructible<A>();
     test_is_copy_constructible<int&>();
@@ -91,4 +91,6 @@ int main()
 #if TEST_STD_VER >= 11
     test_is_not_copy_constructible<B>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
index aef79f7fab9..ce2ec95618e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_default_constructible.pass.cpp
@@ -81,7 +81,7 @@ class B
     B();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_default_constructible<A>();
     test_is_default_constructible<Union>();
@@ -122,4 +122,6 @@ int main()
     test_is_not_default_constructible<void() &&> ();
 #endif
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
index 8722b78fe43..1a32efa4272 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_destructible.pass.cpp
@@ -97,7 +97,7 @@ struct DeletedVirtualPrivateDestructor   { private:   virtual ~DeletedVirtualPri
 #endif
 
 
-int main()
+int main(int, char**)
 {
     test_is_destructible<A>();
     test_is_destructible<int&>();
@@ -142,4 +142,6 @@ int main()
     test_is_not_destructible<NotEmpty>();
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
index 6dafb55a387..850af8b7a75 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_empty.pass.cpp
@@ -78,7 +78,7 @@ struct bit_one
     int :  1;
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_empty<void>();
     test_is_not_empty<int&>();
@@ -100,4 +100,6 @@ int main()
     test_is_empty<EmptyBase>();
     test_is_empty<StaticMember>();
     test_is_empty<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
index 61aed970ec3..4cded0f928e 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_final.pass.cpp
@@ -48,7 +48,7 @@ void test_is_not_final()
 #endif
 }
 
-int main ()
+int main(int, char**)
 {
     test_is_not_final<int>();
     test_is_not_final<int*>();
@@ -58,4 +58,6 @@ int main ()
     test_is_not_final<U1*>();
     test_is_final    <U2>();
     test_is_not_final<U2*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
index 80bb49509b9..b86ff5a8546 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_literal_type.pass.cpp
@@ -69,7 +69,7 @@ enum Enum {zero, one};
 
 typedef void (*FunctionPtr)();
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     test_is_literal_type<std::nullptr_t>();
@@ -101,4 +101,6 @@ int main()
 
     test_is_not_literal_type<NotEmpty>();
     test_is_not_literal_type<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
index edf825dd716..5a330c6d34b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_assignable.pass.cpp
@@ -53,7 +53,7 @@ struct A
     A();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_move_assignable<int> ();
     test_is_move_assignable<A> ();
@@ -68,4 +68,6 @@ int main()
     test_is_not_move_assignable<int[3]> ();
 #endif
     test_is_not_move_assignable<void> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
index 3052d3925d7..06ca5c4630c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_move_constructible.pass.cpp
@@ -66,7 +66,7 @@ struct B
 #endif
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_move_constructible<char[3]>();
     test_is_not_move_constructible<char[]>();
@@ -84,4 +84,6 @@ int main()
     test_is_move_constructible<NotEmpty>();
     test_is_move_constructible<bit_zero>();
     test_is_move_constructible<B>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
index c0a22e3b7a0..be1f016a4eb 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_assignable.pass.cpp
@@ -45,7 +45,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_nothrow_assignable<int&, int&> ();
     test_is_nothrow_assignable<int&, int> ();
@@ -58,4 +58,6 @@ int main()
     test_is_not_nothrow_assignable<B, A> ();
     test_is_not_nothrow_assignable<A, B> ();
     test_is_not_nothrow_assignable<C, C&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
index e9c256acaff..0d171261a59 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_constructible.pass.cpp
@@ -97,7 +97,7 @@ struct Tuple {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_is_nothrow_constructible<int> ();
     test_is_nothrow_constructible<int, const int&> ();
@@ -114,4 +114,6 @@ int main()
     static_assert(!std::is_constructible<Tuple&, Empty>::value, "");
     test_is_not_nothrow_constructible<Tuple &, Empty> (); // See bug #19616.
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
index a3d2611c93a..64895adf45c 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_assignable.pass.cpp
@@ -52,7 +52,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_nothrow_assign<int&>();
     test_has_nothrow_assign<Union>();
@@ -68,4 +68,6 @@ int main()
     test_has_not_nothrow_assign<void>();
     test_has_not_nothrow_assign<A>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
index 4caaeca259d..6b1708839ae 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_copy_constructible.pass.cpp
@@ -55,7 +55,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_copy_constructor<void>();
     test_has_not_nothrow_copy_constructor<A>();
@@ -68,4 +68,6 @@ int main()
     test_is_nothrow_copy_constructible<int*>();
     test_is_nothrow_copy_constructible<const int*>();
     test_is_nothrow_copy_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
index 6e443b303ce..c30facc516b 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_default_constructible.pass.cpp
@@ -67,7 +67,7 @@ struct DThrows
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_default_constructor<void>();
     test_has_not_nothrow_default_constructor<int&>();
@@ -84,4 +84,6 @@ int main()
     test_is_nothrow_default_constructible<const int*>();
     test_is_nothrow_default_constructible<char[3]>();
     test_is_nothrow_default_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
index f58a93ce28a..817d696d11f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp
@@ -79,7 +79,7 @@ class Abstract
 };
 
 
-int main()
+int main(int, char**)
 {
     test_is_not_nothrow_destructible<void>();
     test_is_not_nothrow_destructible<char[]>();
@@ -110,4 +110,6 @@ int main()
     test_is_not_nothrow_destructible<PureProtectedDestructor>();
     test_is_not_nothrow_destructible<PurePrivateDestructor>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
index cb446ef0123..4bcbabbcc4a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_assignable.pass.cpp
@@ -52,7 +52,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_nothrow_assign<int&>();
     test_has_nothrow_assign<Union>();
@@ -66,4 +66,6 @@ int main()
 
     test_has_not_nothrow_assign<void>();
     test_has_not_nothrow_assign<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
index ce002e8204c..ab9e0c6bb4f 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_move_constructible.pass.cpp
@@ -55,7 +55,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_nothrow_move_constructor<void>();
     test_has_not_nothrow_move_constructor<A>();
@@ -68,4 +68,6 @@ int main()
     test_is_nothrow_move_constructible<int*>();
     test_is_nothrow_move_constructible<const int*>();
     test_is_nothrow_move_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
index c90f938c5dc..f554199c606 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable.pass.cpp
@@ -46,7 +46,7 @@ struct ThrowingMove {
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -79,4 +79,6 @@ int main()
         static_assert(std::is_nothrow_swappable_v<int>, "");
         static_assert(!std::is_nothrow_swappable_v<void>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
index 2121f75b092..fb4beac17c9 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_swappable_with.pass.cpp
@@ -45,7 +45,7 @@ void swap(M&&, M&&) noexcept {}
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -77,4 +77,6 @@ int main()
         static_assert(std::is_nothrow_swappable_with_v<int&, int&>, "");
         static_assert(!std::is_nothrow_swappable_with_v<int&&, int&&>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
index f0dac244c9b..87fe6ebbee8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_pod.pass.cpp
@@ -49,7 +49,7 @@ public:
     ~Class();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_pod<void>();
     test_is_not_pod<int&>();
@@ -61,4 +61,6 @@ int main()
     test_is_pod<const int*>();
     test_is_pod<char[3]>();
     test_is_pod<char[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
index feb8f270e52..8829fea6bd7 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_polymorphic.pass.cpp
@@ -72,7 +72,7 @@ class Final {
 };
 #endif
 
-int main()
+int main(int, char**)
 {
     test_is_not_polymorphic<void>();
     test_is_not_polymorphic<int&>();
@@ -91,4 +91,6 @@ int main()
 
     test_is_polymorphic<NotEmpty>();
     test_is_polymorphic<Abstract>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
index 5e9042c797e..4936cc788e2 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_signed.pass.cpp
@@ -51,7 +51,7 @@ public:
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_not_signed<void>();
     test_is_not_signed<int&>();
@@ -71,4 +71,6 @@ int main()
     test_is_signed<__int128_t>();
     test_is_not_signed<__uint128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
index 10f23cca988..fb096c89ad0 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_standard_layout.pass.cpp
@@ -50,11 +50,13 @@ struct pair
     T2 second;
 };
 
-int main()
+int main(int, char**)
 {
     test_is_standard_layout<int> ();
     test_is_standard_layout<int[3]> ();
     test_is_standard_layout<pair<int, double> > ();
 
     test_is_not_standard_layout<int&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
index 3e0980bd5cf..5768a954d64 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable.pass.cpp
@@ -63,7 +63,7 @@ void swap(T&, T&) {}
 
 } // end namespace MyNS2
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -94,4 +94,6 @@ int main()
         static_assert(std::is_swappable_v<int>, "");
         static_assert(!std::is_swappable_v<M>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
index 5d21f3699b3..5931e7ce7f3 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_include_order.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     // Use a builtin type so we don't get ADL lookup.
     typedef double T[17][29];
@@ -39,4 +39,6 @@ int main()
        std::iter_swap(t1, t2);
        std::swap_ranges(t1, t1 + 17, t2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
index f11f9333860..cd65d14efc0 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_swappable_with.pass.cpp
@@ -45,7 +45,7 @@ void swap(M&&, M&&) {}
 
 } // namespace MyNS
 
-int main()
+int main(int, char**)
 {
     using namespace MyNS;
     {
@@ -74,4 +74,6 @@ int main()
         static_assert(std::is_swappable_with_v<int&, int&>, "");
         static_assert(!std::is_swappable_with_v<D&, C&>, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
index 4350f12997f..8bb1b7c9b09 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivial.pass.cpp
@@ -51,7 +51,7 @@ public:
     B();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivial<int> ();
     test_is_trivial<A> ();
@@ -59,4 +59,6 @@ int main()
     test_is_not_trivial<int&> ();
     test_is_not_trivial<volatile int&> ();
     test_is_not_trivial<B> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
index a85f57a5e00..124480c0755 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_assignable.pass.cpp
@@ -47,7 +47,7 @@ struct C
     void operator=(C&);  // not const
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_assignable<int&, int&> ();
     test_is_trivially_assignable<int&, int> ();
@@ -58,4 +58,6 @@ int main()
     test_is_not_trivially_assignable<B, A> ();
     test_is_not_trivially_assignable<A, B> ();
     test_is_not_trivially_assignable<C&, C&> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
index 78ae8cfa99f..42d54bd7e25 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_constructible.pass.cpp
@@ -65,7 +65,7 @@ struct A
     A(int, double);
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_constructible<int> ();
     test_is_trivially_constructible<int, const int&> ();
@@ -73,4 +73,6 @@ int main()
     test_is_not_trivially_constructible<A, int> ();
     test_is_not_trivially_constructible<A, int, double> ();
     test_is_not_trivially_constructible<A> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
index 853c8aa32b5..91fbf69f4f2 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_assignable.pass.cpp
@@ -59,7 +59,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_trivially_copy_assignable<int&>();
     test_has_trivially_copy_assignable<Union>();
@@ -76,4 +76,6 @@ int main()
     test_has_not_trivially_copy_assignable<Abstract>();
     test_has_not_trivially_copy_assignable<const Empty>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
index decd7ffeafa..5744d2ca0e8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copy_constructible.pass.cpp
@@ -65,7 +65,7 @@ struct A
     A(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_copy_constructor<void>();
     test_has_not_trivial_copy_constructor<A>();
@@ -80,4 +80,6 @@ int main()
     test_is_trivially_copy_constructible<int*>();
     test_is_trivially_copy_constructible<const int*>();
     test_is_trivially_copy_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
index 073ea681d6e..51ac0803e66 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_copyable.pass.cpp
@@ -65,7 +65,7 @@ public:
     C();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_trivially_copyable<int> ();
     test_is_trivially_copyable<const int> ();
@@ -76,4 +76,6 @@ int main()
     test_is_not_trivially_copyable<int&> ();
     test_is_not_trivially_copyable<const A&> ();
     test_is_not_trivially_copyable<B> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
index 2f70ba606a2..03ac030a3d7 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_default_constructible.pass.cpp
@@ -69,7 +69,7 @@ struct A
     A();
 };
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_default_constructor<void>();
     test_has_not_trivial_default_constructor<int&>();
@@ -85,4 +85,6 @@ int main()
     test_is_trivially_default_constructible<const int*>();
     test_is_trivially_default_constructible<char[3]>();
     test_is_trivially_default_constructible<bit_zero>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
index 37ea513fcf2..e79e4926b0d 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_destructible.pass.cpp
@@ -87,7 +87,7 @@ struct A
     ~A();
 };
 
-int main()
+int main(int, char**)
 {
     test_is_not_trivially_destructible<void>();
     test_is_not_trivially_destructible<A>();
@@ -115,4 +115,6 @@ int main()
     test_is_not_trivially_destructible<PureProtectedDestructor>();
     test_is_not_trivially_destructible<PurePrivateDestructor>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
index c4aa7b7dced..0a91efdf089 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_assignable.pass.cpp
@@ -59,7 +59,7 @@ struct A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
     test_has_trivial_assign<int&>();
     test_has_trivial_assign<Union>();
@@ -76,4 +76,6 @@ int main()
     test_has_not_trivial_assign<Abstract>();
     test_has_not_trivial_assign<const Empty>();
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
index 6f47ed6fd4d..78c10a1320a 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_trivially_move_constructible.pass.cpp
@@ -75,7 +75,7 @@ struct MoveOnly2
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test_has_not_trivial_move_constructor<void>();
     test_has_not_trivial_move_constructor<A>();
@@ -94,4 +94,6 @@ int main()
     static_assert(!std::is_trivially_move_constructible<MoveOnly1>::value, "");
     static_assert( std::is_trivially_move_constructible<MoveOnly2>::value, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
index 86e5611c7b2..bc70a43b9bd 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_unsigned.pass.cpp
@@ -51,7 +51,7 @@ public:
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_not_unsigned<void>();
     test_is_not_unsigned<int&>();
@@ -71,4 +71,6 @@ int main()
     test_is_unsigned<__uint128_t>();
     test_is_not_unsigned<__int128_t>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
index 28cb29f3bd9..cb0fc3c6ea8 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/meta.unary.prop/is_volatile.pass.cpp
@@ -30,7 +30,7 @@ void test_is_volatile()
 
 struct A; // incomplete
 
-int main()
+int main(int, char**)
 {
     test_is_volatile<void>();
     test_is_volatile<int>();
@@ -44,4 +44,6 @@ int main()
 
     static_assert(!std::is_volatile<int&>::value, "");
     static_assert(!std::is_volatile<volatile int&>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/meta/meta.unary/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp b/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
index cfae639636a..9bcfa8e4656 100644
--- a/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.bad_optional_access/default.pass.cpp
@@ -23,8 +23,10 @@
 #include <optional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using std::bad_optional_access;
     bad_optional_access ex;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp b/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
index 80f2372e456..ac7be93f709 100644
--- a/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.bad_optional_access/derive.pass.cpp
@@ -23,10 +23,12 @@
 #include <optional>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using std::bad_optional_access;
 
     static_assert(std::is_base_of<std::exception, bad_optional_access>::value, "");
     static_assert(std::is_convertible<bad_optional_access*, std::exception*>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
index dbf8a0564b5..4f7aedbcb0f 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator==(const X& lhs, const X& rhs) {
   return lhs.i_ == rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 == 42, "");
     static_assert(!(101 == o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
index 539e35fe065..373634f68c2 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater.pass.cpp
@@ -24,7 +24,7 @@ struct X {
 
 constexpr bool operator>(const X& lhs, const X& rhs) { return lhs.i_ > rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 > 11, "");
     static_assert(!(42 > o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
index c7bbbda8580..5d4839734bb 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/greater_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator>=(const X& lhs, const X& rhs) {
   return lhs.i_ >= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -62,4 +62,6 @@ int main() {
     static_assert(o1 >= 42, "");
     static_assert(!(11 >= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
index 73ed8564340..a601939c5b3 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator<=(const X& lhs, const X& rhs) {
   return lhs.i_ <= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -62,4 +62,6 @@ int main() {
     static_assert(o1 <= 42, "");
     static_assert(!(101 <= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
index c0c111afdca..7320955908a 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/less_than.pass.cpp
@@ -24,7 +24,7 @@ struct X {
 
 constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 < 101, "");
     static_assert(!(42 < o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
index 949a03a8c5b..0d14f1e97a9 100644
--- a/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.comp_with_t/not_equal.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool operator!=(const X& lhs, const X& rhs) {
   return lhs.i_ != rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -60,4 +60,6 @@ int main() {
     static_assert(o1 != 101, "");
     static_assert(!(42 != o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
index a842804f374..66ab089dc30 100644
--- a/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.hash/enabled_hash.pass.cpp
@@ -17,9 +17,11 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
 
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp b/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
index 0f74557b730..aa89a51d8d4 100644
--- a/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.hash/hash.pass.cpp
@@ -30,7 +30,7 @@ struct hash<B> {
 
 }
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     const std::size_t nullopt_hash =
@@ -76,4 +76,6 @@ int main()
       test_hash_enabled_for_type<std::optional<B>>();
       test_hash_enabled_for_type<std::optional<const B>>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
index 05413c1f14d..5894462205a 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt == o1), "");
     static_assert (noexcept(o1 == nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
index 7bc764d01b8..59dc62fce17 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/greater.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt > o1), "");
     static_assert (noexcept(o1 > nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
index 7c77a95a150..e23e8794f44 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/greater_equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt >= o1), "");
     static_assert (noexcept(o1 >= nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
index 1d3994e4a50..96f0754e40b 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/less_equal.pass.cpp
@@ -15,7 +15,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -36,4 +36,6 @@ int main()
     static_assert (noexcept(nullopt <= o1), "");
     static_assert (noexcept(o1 <= nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
index 3b313c946d7..872f3159a92 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/less_than.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt < o1), "");
     static_assert (noexcept(o1 < nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
index 9b3c41c1c48..7eea0fa8856 100644
--- a/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullops/not_equal.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -35,4 +35,6 @@ int main()
     static_assert (noexcept(nullopt != o1), "");
     static_assert (noexcept(o1 != nullopt), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
index 9cbbc8bd972..2a7822ebb63 100644
--- a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.fail.cpp
@@ -18,7 +18,9 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     std::nullopt_t n = {};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
index f664433cb42..c9d843e9c2a 100644
--- a/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.nullopt/nullopt_t.pass.cpp
@@ -29,11 +29,13 @@ constexpr bool test()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_empty_v<nullopt_t>);
     static_assert(!std::is_default_constructible_v<nullopt_t>);
 
     static_assert(std::is_same_v<const nullopt_t, decltype(nullopt)>);
     static_assert(test());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
index e40af08233a..8d2a8a00c94 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/assign_value.pass.cpp
@@ -241,7 +241,7 @@ enum MyEnum { Zero, One, Two, Three, FortyTwo = 42 };
 
 using Fn = void(*)();
 
-int main()
+int main(int, char**)
 {
     test_sfinae();
     // Test with instrumented type
@@ -268,4 +268,6 @@ int main()
         assert(**opt == 3);
     }
     test_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
index a9a1c07d898..6ccaafa6d6f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/const_optional_U.pass.cpp
@@ -196,7 +196,7 @@ void test_ambigious_assign() {
 }
 
 
-int main()
+int main(int, char**)
 {
     test_with_test_type();
     test_ambigious_assign();
@@ -250,4 +250,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
index 8a4540e18e6..5900e60461e 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/copy.pass.cpp
@@ -48,7 +48,7 @@ constexpr bool assign_value(optional<Tp>&& lhs) {
     return lhs.has_value() && rhs.has_value() && *lhs == *rhs;
 }
 
-int main()
+int main(int, char**)
 {
     {
         using O = optional<int>;
@@ -102,4 +102,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
index cf09bb5ddde..c5cebc5420b 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace.pass.cpp
@@ -208,7 +208,7 @@ void test_on_test_type() {
 
 
 
-int main()
+int main(int, char**)
 {
     {
         test_on_test_type<TestTypes::TestType>();
@@ -265,4 +265,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
index 9141bea11c9..446e9ae9668 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/emplace_initializer_list.pass.cpp
@@ -69,7 +69,7 @@ public:
 
 bool Z::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         X x;
@@ -117,4 +117,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
index 0c36da93d92..c862c5f0efd 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/move.pass.cpp
@@ -66,7 +66,7 @@ constexpr bool assign_value(optional<Tp>&& lhs) {
     return lhs.has_value() && rhs.has_value() && *lhs == Tp{101};
 }
 
-int main()
+int main(int, char**)
 {
     {
         static_assert(std::is_nothrow_move_assignable<optional<int>>::value, "");
@@ -204,4 +204,5 @@ int main()
         };
         static_assert(std::is_nothrow_move_assignable<optional<NoThrowMove>>::value, "");
     }
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
index e6b67430fff..af582d73205 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/nullopt_t.pass.cpp
@@ -22,7 +22,7 @@ using std::optional;
 using std::nullopt_t;
 using std::nullopt;
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt;
@@ -63,4 +63,6 @@ int main()
     assert(TT::alive == 0);
     assert(TT::destroyed == 1);
     TT::reset();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
index d043fd1def8..cabaa070b27 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.assign/optional_U.pass.cpp
@@ -201,7 +201,7 @@ void test_ambigious_assign() {
 }
 
 
-int main()
+int main(int, char**)
 {
     test_with_test_type();
     test_ambigious_assign();
@@ -264,4 +264,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
index 861ab91d80f..f91cd110f96 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/U.pass.cpp
@@ -153,7 +153,9 @@ void test_explicit() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
     test_implicit();
     test_explicit();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
index 462811e5103..1a7b36a5bf3 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_T.pass.cpp
@@ -29,7 +29,7 @@
 
 using std::optional;
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -132,4 +132,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
index 4666d6d9b7f..b28d22330a9 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/const_optional_U.pass.cpp
@@ -78,7 +78,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef short U;
@@ -130,4 +130,6 @@ int main()
     }
 
     static_assert(!(std::is_constructible<optional<X>, const optional<Y>&>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
index 844abda00ee..e6793cd4794 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/copy.pass.cpp
@@ -113,7 +113,7 @@ void test_reference_extension()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<int>(3);
@@ -169,4 +169,6 @@ int main()
         constexpr std::optional<int> o2 = o1;
         static_assert( *o2 == 4, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
index 9439642418f..7c6ae9bcdac 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.fail.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
 
@@ -42,4 +42,6 @@ int main()
 //  optional(nullopt_t)
     std::optional opt(std::nullopt);   // expected-error-re@optional:* {{static_assert failed{{.*}} "instantiation of optional with nullopt_t is ill-formed"}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
index 973b49dff19..fa2edfcdd69 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/deduct.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
 //  Test the explicit deduction guides
     {
@@ -50,4 +50,6 @@ int main()
     assert(static_cast<bool>(opt) == static_cast<bool>(source));
     assert(*opt == *source);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
index a00fa170609..3dd38da9d57 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/default.pass.cpp
@@ -61,7 +61,7 @@ test()
     };
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr<optional<int>>();
     test_constexpr<optional<int*>>();
@@ -77,4 +77,6 @@ int main()
     test_constexpr<optional<NonLiteralTypes::NoCtors&>>();
     test_constexpr<optional<NonLiteralTypes::NoCtors&&>>();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
index 37adf8bbe06..7741e035342 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_const_optional_U.pass.cpp
@@ -79,7 +79,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef X T;
@@ -117,4 +117,6 @@ int main()
         optional<U> rhs(3);
         test<T>(rhs, true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
index ea4b7aa50da..71febba3529 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/explicit_optional_U.pass.cpp
@@ -62,7 +62,7 @@ public:
     explicit Z(int) { TEST_THROW(6); }
 };
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> rhs;
@@ -80,4 +80,6 @@ int main()
         optional<int> rhs(3);
         test<Z>(std::move(rhs), true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
index 5cd23bad045..db995b4a7e8 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/in_place_t.pass.cpp
@@ -58,7 +58,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<int> opt(in_place, 5);
@@ -144,4 +144,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
index f62e6a3a89e..c8c76df2567 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/initializer_list.pass.cpp
@@ -66,7 +66,7 @@ public:
         {return x.i_ == y.i_ && x.j_ == y.j_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         static_assert(!std::is_constructible<X, std::initializer_list<int>&>::value, "");
@@ -112,4 +112,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
index 622b8e428a0..a8634b961c7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.fail.cpp
@@ -28,9 +28,11 @@ struct S {
     };
 
 
-int main()
+int main(int, char**)
 {
     static_assert (!std::is_trivially_move_constructible_v<S>, "" );
     constexpr std::optional<S> o1;
     constexpr std::optional<S> o2 = std::move(o1);  // not constexpr
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
index afba631bf95..bf536ec6342 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/move.pass.cpp
@@ -151,7 +151,7 @@ void test_reference_extension()
 }
 
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<int>(3);
@@ -225,4 +225,6 @@ int main()
     constexpr std::optional<int> o2 = std::move(o1);
     static_assert( *o2 == 4, "" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
index 850ed6ecaad..927ac19ead1 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/nullopt_t.pass.cpp
@@ -61,7 +61,7 @@ test()
     };
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr<optional<int>>();
     test_constexpr<optional<int*>>();
@@ -69,4 +69,6 @@ int main()
     test_constexpr<optional<NonTrivialTypes::NoCtors>>();
     test_constexpr<optional<NonConstexprTypes::NoCtors>>();
     test<optional<NonLiteralTypes::NoCtors>>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
index fd74f9ae18c..fe4252b49c7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/optional_U.pass.cpp
@@ -61,7 +61,7 @@ struct Z
     Z(int) { TEST_THROW(6); }
 };
 
-int main()
+int main(int, char**)
 {
     {
         optional<short> rhs;
@@ -89,4 +89,6 @@ int main()
     }
 
     static_assert(!(std::is_constructible<optional<X>, optional<Z>>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
index 5e9a216dcb9..7fd1f2fa16e 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.ctor/rvalue_T.pass.cpp
@@ -39,7 +39,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -157,4 +157,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
index ca96586a139..23497bc4c47 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.dtor/dtor.pass.cpp
@@ -32,7 +32,7 @@ public:
 
 bool X::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         typedef int T;
@@ -64,4 +64,6 @@ int main()
         }
         assert(X::dtor_called == true);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
index e766db87eb6..704606c6f75 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.mod/reset.pass.cpp
@@ -26,7 +26,7 @@ struct X
 
 bool X::dtor_called = false;
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<bool>(opt) == false);
         X::dtor_called = false;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
index 29bf20bbd08..7c008ef6209 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/bool.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -33,4 +33,6 @@ int main()
         constexpr optional<int> opt(0);
         static_assert(opt, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
index b109346f588..368f84155db 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference.pass.cpp
@@ -43,7 +43,7 @@ test()
     return (*opt).test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
index 6663d88513f..99a60e8dd6f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const.pass.cpp
@@ -36,7 +36,7 @@ struct Y
     int test() const {return 2;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -65,4 +65,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
index 02466d53b11..ca494c5a83d 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_const_rvalue.pass.cpp
@@ -36,7 +36,7 @@ struct Y
     int test() const && {return 2;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -65,4 +65,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
index 7dca9f61345..f1b2ca393af 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/dereference_rvalue.pass.cpp
@@ -43,7 +43,7 @@ test()
     return (*std::move(opt)).test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
index 59ce4c7e8ee..560fa8894b7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/has_value.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -33,4 +33,6 @@ int main()
         constexpr optional<int> opt(0);
         static_assert(opt.has_value(), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
index ac0b9a52788..8c6c0986140 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow.pass.cpp
@@ -40,7 +40,7 @@ test()
     return opt->test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::optional<X> opt; ((void)opt);
@@ -68,4 +68,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
index fd7e683be77..b9539828a98 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/op_arrow_const.pass.cpp
@@ -39,7 +39,7 @@ struct Z
     constexpr int test() const {return 1;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const std::optional<X> opt; ((void)opt);
@@ -72,4 +72,6 @@ int main()
         assert(false);
     }
 #endif  // _LIBCPP_DEBUG
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
index 04a4fcffd90..23fd85ba53f 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value.pass.cpp
@@ -52,7 +52,7 @@ test()
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -78,4 +78,6 @@ int main()
     }
 #endif
     static_assert(test() == 7, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
index ab6504dba9f..5e81f2fb11d 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.fail.cpp
@@ -23,10 +23,12 @@ struct X
     int test() {return 4;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<X> opt;
         static_assert(opt.value().test() == 3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
index dcc9306b152..54bdc1001d9 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const.pass.cpp
@@ -41,7 +41,7 @@ struct X
     int test() && {return 6;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
index 5e218d80e3f..b330bb8db87 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_const_rvalue.pass.cpp
@@ -41,7 +41,7 @@ struct X
     int test() && {return 6;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         const optional<X> opt; ((void)opt);
@@ -69,4 +69,6 @@ int main()
         }
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
index 93ec45b0bec..8f22f1c0dc8 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or.pass.cpp
@@ -67,7 +67,9 @@ constexpr int test()
     return 0;
 }
 
-int main()
+int main(int, char**)
 {
     static_assert(test() == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
index 0b4c7928f21..736fe791af6 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_or_const.pass.cpp
@@ -35,7 +35,7 @@ struct X
         {return x.i_ == y.i_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         constexpr optional<X> opt(2);
@@ -73,4 +73,6 @@ int main()
         const optional<X> opt;
         assert(opt.value_or(Y(3)) == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
index 21f630e8c36..06206a324d4 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.observe/value_rvalue.pass.cpp
@@ -50,7 +50,7 @@ test()
     return std::move(opt).value().test();
 }
 
-int main()
+int main(int, char**)
 {
     {
         optional<X> opt; ((void)opt);
@@ -76,4 +76,6 @@ int main()
     }
 #endif
     static_assert(test() == 7, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
index 7d79251e241..e881a0c6286 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional.object.swap/swap.pass.cpp
@@ -64,7 +64,7 @@ public:
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         optional<int> opt1;
@@ -302,4 +302,6 @@ int main()
         assert(*opt2 == 2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp b/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
index 67e1b76d7cb..531173ade8b 100644
--- a/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/optional_requires_destructible_object.fail.cpp
@@ -21,7 +21,7 @@ private:
     ~X() {}
 };
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     {
@@ -46,4 +46,6 @@ int main()
     }
     // FIXME these are garbage diagnostics that Clang should not produce
     // expected-error@optional:* 0+ {{is not a base class}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
index a315ed8ca75..28783264d71 100644
--- a/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/special_members.pass.cpp
@@ -52,11 +52,12 @@ struct DoTestsMetafunction {
     DoTestsMetafunction() { sink(SpecialMemberTest<TestTypes>{}...); }
 };
 
-int main() {
+int main(int, char**) {
     sink(
         ImplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         ExplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         NonLiteralTypes::ApplyTypes<DoTestsMetafunction>{},
         NonTrivialTypes::ApplyTypes<DoTestsMetafunction>{}
     );
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
index 7c82e17d611..f53d86000e7 100644
--- a/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/triviality.pass.cpp
@@ -85,7 +85,7 @@ struct TrivialCopyNonTrivialMove {
     TrivialCopyNonTrivialMove& operator=(TrivialCopyNonTrivialMove&&) { return *this; }
 };
 
-int main() {
+int main(int, char**) {
     sink(
         ImplicitTypes::ApplyTypes<DoTestsMetafunction>{},
         ExplicitTypes::ApplyTypes<DoTestsMetafunction>{},
@@ -93,4 +93,5 @@ int main() {
         NonTrivialTypes::ApplyTypes<DoTestsMetafunction>{},
         DoTestsMetafunction<TrivialMoveNonTrivialCopy, TrivialCopyNonTrivialMove>{}
     );
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp b/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
index cef295754ee..7c32d1857cd 100644
--- a/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.object/types.pass.cpp
@@ -28,10 +28,12 @@ test()
     static_assert(std::is_same<typename Opt::value_type, T>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test<optional<int>, int>();
     test<optional<const int>, const int>();
     test<optional<double>, double>();
     test<optional<const double>, const double>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
index baeb16bb6b8..4fc85157a76 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/equal.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool operator==(const X& lhs, const X& rhs) {
   return lhs.i_ == rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -82,4 +82,6 @@ int main() {
     static_assert(o1 == O2(42), "");
     static_assert(!(O2(101) == o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
index 3a88640cad9..4bc9720aa7f 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/greater_equal.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool operator>=(const X& lhs, const X& rhs) {
   return lhs.i_ >= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -79,4 +79,6 @@ int main() {
     static_assert(o1 >= O2(42), "");
     static_assert(!(O2(1) >= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
index 7f7b24a75f6..d168cd70635 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/greater_than.pass.cpp
@@ -23,7 +23,7 @@ struct X {
 
 constexpr bool operator>(const X& lhs, const X& rhs) { return lhs.i_ > rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -77,4 +77,6 @@ int main() {
     static_assert(o1 > O2(1), "");
     static_assert(!(O2(42) > o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
index e9180cb3ee6..835be64f8fb 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/less_equal.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool operator<=(const X& lhs, const X& rhs) {
   return lhs.i_ <= rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -79,4 +79,6 @@ int main() {
     static_assert(o1 <= O2(42), "");
     static_assert(!(O2(101) <= o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
index 29fa36a3edb..832de4b2981 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/less_than.pass.cpp
@@ -23,7 +23,7 @@ struct X {
 
 constexpr bool operator<(const X& lhs, const X& rhs) { return lhs.i_ < rhs.i_; }
 
-int main() {
+int main(int, char**) {
   {
     typedef optional<X> O;
 
@@ -77,4 +77,6 @@ int main() {
     static_assert(o1 < O2(101), "");
     static_assert(!(O2(101) < o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp b/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
index 9f690477e0e..ab00b7aab18 100644
--- a/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.relops/not_equal.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool operator!=(const X& lhs, const X& rhs) {
   return lhs.i_ != rhs.i_;
 }
 
-int main() {
+int main(int, char**) {
   {
     typedef X T;
     typedef optional<T> O;
@@ -82,4 +82,6 @@ int main() {
     static_assert(o1 != O2(101), "");
     static_assert(!(O2(42) != o1), "");
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
index fef17e77277..7725289275f 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::make_optional;
@@ -55,4 +55,6 @@ int main()
         assert(**opt == 3);
         assert(s == nullptr);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
index 675e9003673..d3461542b93 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit.pass.cpp
@@ -17,7 +17,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::make_optional;
@@ -41,4 +41,6 @@ int main()
         auto opt = make_optional<std::string>(4, 'X');
         assert(*opt == "XXXX");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
index 4a9040e50f7..40b20bed52b 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/make_optional_explicit_initializer_list.pass.cpp
@@ -27,7 +27,7 @@ struct TestT {
       : x(*il.begin()), size(static_cast<int>(il.size())) {}
 };
 
-int main()
+int main(int, char**)
 {
     using std::make_optional;
     {
@@ -49,4 +49,6 @@ int main()
         auto opt = make_optional<std::string>({'a', 'b', 'c'}, std::allocator<char>{});
         assert(*opt == "abc");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp b/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
index 3f37ac6e272..1a548e8cc2e 100644
--- a/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.specalg/swap.pass.cpp
@@ -109,7 +109,7 @@ void test_swap_sfinae() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_swap_sfinae();
     {
@@ -348,4 +348,6 @@ int main()
         assert(*opt2 == 2);
     }
 #endif // TEST_HAS_NO_EXCEPTIONS
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
index aca546d6c44..b7d3b71e0d3 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_in_place_t.fail.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::in_place_t;
@@ -22,4 +22,6 @@ int main()
 
     optional<in_place_t> opt; // expected-note {{requested here}}
     // expected-error@optional:* {{"instantiation of optional with in_place_t is ill-formed"}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
index 28904aecf12..daaad5664b6 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_includes_initializer_list.pass.cpp
@@ -13,10 +13,12 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
 
     std::initializer_list<int> list;
     (void)list;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp b/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
index 4fe41b44518..a4abbf02779 100644
--- a/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
+++ b/libcxx/test/std/utilities/optional/optional.syn/optional_nullopt_t.fail.cpp
@@ -14,7 +14,7 @@
 
 #include <optional>
 
-int main()
+int main(int, char**)
 {
     using std::optional;
     using std::nullopt_t;
@@ -25,4 +25,6 @@ int main()
     optional<nullopt_t &> opt2; // expected-note 1 {{requested here}}
     optional<nullopt_t &&> opt3; // expected-note 1 {{requested here}}
     // expected-error@optional:* 4 {{instantiation of optional with nullopt_t is ill-formed}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
index d7f775eee6e..abf75631f86 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_add<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
index ae43ac9222b..c62f75a0d87 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_add<R1, R2>::type R;
     static_assert(R::num == 1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
index ea96434b855..387f6290368 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 2> R2;
     typedef std::ratio_divide<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
index 0b93e1a9cea..ce7f69473bc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_divide<R1, R2>::type R;
     static_assert(R::num == 630992477165LL && R::den == 127339199162436LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
index b884f4e2cb8..ef59bb39e41 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<2, 1> R2;
     typedef std::ratio_multiply<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
index 876158994e7..e20f2344347 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_multiply<R1, R2>::type R;
     static_assert(R::num == 15519594064236LL && R::den == 5177331081415LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
index 95e9c823908..8b00462dc48 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<-0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_subtract<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
index dbb9480475d..e3871f7a7cf 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_subtract<R1, R2>::type R;
     static_assert(R::num == -1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
index 9f547cdea56..d0b1d5a17be 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
index ab6deac86d0..dfb0e8fe87e 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
index 79942fa6d0d..811706c58aa 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
index a80112ca4b8..45ba7cbf16c 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -93,4 +93,6 @@ int main()
     typedef std::ratio<641981, 1339063> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
index c5dbdedc8f6..ebb8624a85f 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
index 68e6aba35d0..5000e73d3fc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
index bb3bb159bde..336d7d8e5b5 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
@@ -18,7 +18,7 @@ void test()
     static_assert((std::ratio<N, D>::den == eD), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<1, 1, 1, 1>();
     test<1, 10, 1, 10>();
@@ -40,4 +40,6 @@ int main()
     test<-0x7FFFFFFFFFFFFFFFLL, 127, -72624976668147841LL, 1>();
     test<0x7FFFFFFFFFFFFFFFLL, -127, -72624976668147841LL, 1>();
     test<-0x7FFFFFFFFFFFFFFFLL, -127, 72624976668147841LL, 1>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
index 1c143f659cb..0841d858dc9 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
@@ -11,7 +11,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
index bf56271fbbe..f8bebc8624d 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<0x8000000000000000ULL, 1>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
index 6e44427f841..78310c6a245 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0x8000000000000000ULL>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
index 3f54f555a89..8e24ff9749d 100644
--- a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::atto::num == 1 && std::atto::den == 1000000000000000000ULL, "");
     static_assert(std::femto::num == 1 && std::femto::den == 1000000000000000ULL, "");
@@ -28,4 +28,6 @@ int main()
     static_assert(std::tera::num == 1000000000000ULL && std::tera::den == 1, "");
     static_assert(std::peta::num == 1000000000000000ULL && std::peta::den == 1, "");
     static_assert(std::exa::num == 1000000000000000000ULL && std::exa::den == 1, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
index cb7a5bbf6ab..f0ca5b0ea86 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/pointer_type.pass.cpp
@@ -54,7 +54,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
index e11ec4b4004..bc42afda309 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move.pass.cpp
@@ -107,7 +107,7 @@ void test_sfinae() {
 }
 
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_sfinae<false>();
@@ -116,4 +116,6 @@ int main() {
     test_basic</*IsArray*/ true>();
     test_sfinae<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
index b89a452014d..c9ebdf63344 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.pass.cpp
@@ -405,7 +405,7 @@ void test_deleter_value_category() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae</*IsArray*/false>();
     test_noexcept<false>();
@@ -416,4 +416,6 @@ int main() {
     test_noexcept<true>();
     test_deleter_value_category<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
index 0800f869fe6..ce912546533 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.runtime.pass.cpp
@@ -114,7 +114,9 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_sfinae();
   // FIXME: add tests
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
index 2b9bdb8c330..d5f46935a19 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/move_convert.single.pass.cpp
@@ -113,7 +113,7 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_sfinae();
   {
     std::unique_ptr<B> bptr(new B);
@@ -141,4 +141,6 @@ int main() {
   }
   assert(A::count == 0);
   assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
index 28ea9d7b04d..ecba79dfd32 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/null.pass.cpp
@@ -32,7 +32,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
index 91349cb300e..5cd44b2f647 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.asgn/nullptr.pass.cpp
@@ -33,7 +33,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
index e2fe7bb0dd3..577a906fb0e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/auto_pointer.pass.cpp
@@ -61,7 +61,7 @@ void test_sfinae() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     B* p = new B;
     std::auto_ptr<B> ap(p);
@@ -93,4 +93,6 @@ int main() {
   }
 #endif
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
index 3145c0c9f08..1bd53b9a9ca 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/default.pass.cpp
@@ -94,7 +94,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   doIncompleteTypeTest<IncompleteType[], Deleter<IncompleteType[]> >(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae<int>();
     test_basic<int>();
@@ -103,4 +103,6 @@ int main() {
     test_sfinae<int[]>();
     test_basic<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
index f95897b9f92..7c07b2ec984 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move.pass.cpp
@@ -159,7 +159,7 @@ void test_noexcept() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_sfinae<int>();
@@ -170,4 +170,6 @@ int main() {
     test_sfinae<int[]>();
     test_noexcept<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
index f19943a46cc..3d0bb1cd1f6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.pass.cpp
@@ -204,7 +204,7 @@ void test_deleter_value_category() {
 }
 
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae</*IsArray*/false>();
     test_noexcept<false>();
@@ -215,4 +215,6 @@ int main() {
     test_noexcept<true>();
     test_deleter_value_category<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
index 010c2293a16..bcf85b11031 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.runtime.pass.cpp
@@ -77,6 +77,8 @@ void test_sfinae() {
 }
 
 
-int main() {
+int main(int, char**) {
   test_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
index d269544c331..1dcf0cf325c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/move_convert.single.pass.cpp
@@ -157,7 +157,7 @@ void test_noexcept() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     test_sfinae();
     test_noexcept();
@@ -244,4 +244,6 @@ int main() {
     }
     checkNoneAlive();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
index e2694b38af8..d2453883276 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/null.pass.cpp
@@ -61,7 +61,7 @@ void test_pointer_deleter_ctor() {
   }
 }
 
-int main() {
+int main(int, char**) {
   {
     // test_pointer_ctor<int>();
     test_pointer_deleter_ctor<int>();
@@ -70,4 +70,6 @@ int main() {
     test_pointer_ctor<int[]>();
     test_pointer_deleter_ctor<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
index 8d3f94715c8..9ec7f7a4e1d 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/nullptr.pass.cpp
@@ -93,7 +93,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   checkNumIncompleteTypeAlive(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_basic<int>();
     test_sfinae<int>();
@@ -102,4 +102,6 @@ int main() {
     test_basic<int[]>();
     test_sfinae<int[]>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
index 55a5f48b2d3..48d41fc5c0f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer.pass.cpp
@@ -156,7 +156,7 @@ DEFINE_AND_RUN_IS_INCOMPLETE_TEST({
   checkNumIncompleteTypeAlive(0);
 })
 
-int main() {
+int main(int, char**) {
   {
     test_pointer</*IsArray*/ false>();
     test_derived();
@@ -167,4 +167,6 @@ int main() {
     test_sfinae<int[]>();
     test_sfinae_runtime();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
index 4c5536d939c..ccb4924d024 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.fail.cpp
@@ -22,7 +22,9 @@ struct Deleter {
   void operator()(int* p) const { delete p; }
 };
 
-int main() {
+int main(int, char**) {
   // expected-error@+1 {{call to deleted constructor of 'std::unique_ptr<int, const Deleter &>}}
   std::unique_ptr<int, const Deleter&> s((int*)nullptr, Deleter());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
index 246af44f97f..59861effb4e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.ctor/pointer_deleter.pass.cpp
@@ -309,7 +309,7 @@ void test_nullptr() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   {
     test_basic</*IsArray*/ false>();
     test_nullptr<false>();
@@ -324,4 +324,6 @@ int main() {
     test_sfinae_runtime();
     test_noexcept<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
index e7b91655899..9ef48b2e4af 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.dtor/null.pass.cpp
@@ -41,7 +41,9 @@ void test_basic() {
   assert(d.state() == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic<int>();
   test_basic<int[]>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
index cc2a8366e9d..f080165d561 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/release.pass.cpp
@@ -49,7 +49,9 @@ void test_basic() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
index f271a7fb47b..46569918a5f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.pass.cpp
@@ -102,7 +102,7 @@ void test_reset_no_arg() {
   assert(A::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   {
     test_reset_pointer</*IsArray*/ false>();
     test_reset_nullptr<false>();
@@ -113,4 +113,6 @@ int main() {
     test_reset_nullptr<true>();
     test_reset_no_arg<true>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
index 98a4125ba77..7e3085a5b0f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.runtime.fail.cpp
@@ -17,7 +17,7 @@
 
 #include "unique_ptr_test_helper.h"
 
-int main() {
+int main(int, char**) {
   {
     std::unique_ptr<A[]> p;
     p.reset(static_cast<B*>(nullptr)); // expected-error {{no matching member function for call to 'reset'}}
@@ -26,4 +26,6 @@ int main() {
     std::unique_ptr<int[]> p;
     p.reset(static_cast<const int*>(nullptr)); // expected-error {{no matching member function for call to 'reset'}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
index e9d43b60247..4f5a519b798 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset.single.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "unique_ptr_test_helper.h"
 
-int main() {
+int main(int, char**) {
   {
     std::unique_ptr<A> p(new A);
     assert(A::count == 1);
@@ -42,4 +42,6 @@ int main() {
   }
   assert(A::count == 0);
   assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
index 129e3ea45b1..d5e15aafe24 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/reset_self.pass.cpp
@@ -21,4 +21,6 @@ struct A {
   void reset() { ptr_.reset(); }
 };
 
-int main() { (new A)->reset(); }
+int main(int, char**) { (new A)->reset(); 
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
index 935ebab7fda..35e997e3065 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.modifiers/swap.pass.cpp
@@ -81,7 +81,9 @@ void test_basic() {
   assert(TT::count == 0);
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
index 0fd37cbfa06..8a5566b915c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.runtime.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int[]> p(new int(3));
   const std::unique_ptr<int[]>& cp = p;
   TEST_IGNORE_NODISCARD (*p);  // expected-error {{indirection requires pointer operand ('std::unique_ptr<int []>' invalid)}}
   TEST_IGNORE_NODISCARD (*cp); // expected-error {{indirection requires pointer operand ('const std::unique_ptr<int []>' invalid)}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
index 49cfccb6f85..254d88bb6cf 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/dereference.single.pass.cpp
@@ -15,7 +15,9 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int> p(new int(3));
   assert(*p == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
index ce45882a8bf..500821fb817 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/explicit_bool.pass.cpp
@@ -59,7 +59,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
index 76f2b4c6712..1ff965f563e 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get.pass.cpp
@@ -44,7 +44,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
index 31f33a265c6..e440a95991c 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/get_deleter.pass.cpp
@@ -58,7 +58,9 @@ void test_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_basic</*IsArray*/ false>();
   test_basic<true>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
index 886fc95d9de..4fa94f137ce 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.runtime.fail.cpp
@@ -19,7 +19,7 @@ struct V {
   int member;
 };
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<V[]> p;
   std::unique_ptr<V[]> const& cp = p;
 
@@ -28,4 +28,6 @@ int main() {
 
   cp->member; // expected-error {{member reference type 'const std::unique_ptr<V []>' is not a pointer}}
               // expected-error@-1 {{no member named 'member'}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
index 0bc0c7718b8..f31ca6b286d 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_arrow.single.pass.cpp
@@ -21,7 +21,9 @@ struct A {
   A() : i_(7) {}
 };
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<A> p(new A);
   assert(p->i_ == 7);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
index 2b97f8fe569..21e7e661688 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.runtime.pass.cpp
@@ -33,7 +33,7 @@ public:
 
 int A::next_ = 0;
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<A[]> p(new A[3]);
   assert(p[0] == 1);
   assert(p[1] == 2);
@@ -44,4 +44,6 @@ int main() {
   assert(p[0] == 3);
   assert(p[1] == 2);
   assert(p[2] == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
index e5a960a6e80..66286aa8620 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.class/unique.ptr.observers/op_subscript.single.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main() {
+int main(int, char**) {
   std::unique_ptr<int> p(new int[3]);
   std::unique_ptr<int> const& cp = p;
   p[0];  // expected-error {{type 'std::unique_ptr<int>' does not provide a subscript operator}}
   cp[1]; // expected-error {{type 'const std::unique_ptr<int>' does not provide a subscript operator}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
index a77194ecf95..715335eb1cd 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array.pass.cpp
@@ -21,7 +21,7 @@ private:
     int val_;
     };
 
-int main()
+int main(int, char**)
 {
     {
     auto p1 = std::make_unique<int[]>(5);
@@ -40,4 +40,6 @@ int main()
     for ( int i = 0; i < 7; ++i )
         assert ( p3[i].get () == 3 );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
index a0e256fcf1e..56adccf176a 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array1.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up1 = std::make_unique<std::string[]>("error"); // doesn't compile - no bound
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
index 0f366c6c3e2..fda45ab8946 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array2.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up2 = std::make_unique<int[]>(10, 20, 30, 40);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
index 90622fed107..9fa05c79d93 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array3.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up3 = std::make_unique<int[5]>();    // this is deleted
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
index 5c10ac6bb24..d98f052b54f 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.array4.fail.cpp
@@ -10,7 +10,9 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     auto up4 = std::make_unique<int[5]>(11, 22, 33, 44, 55); // deleted
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
index 4adf2e9ae42..08062c122e1 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.create/make_unique.single.pass.cpp
@@ -11,7 +11,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
     std::unique_ptr<int> p1 = std::make_unique<int>(1);
@@ -28,4 +28,6 @@ int main()
     p2 = std::make_unique<std::string> ( 6, 'z' );
     assert ( *p2 == "zzzzzz" );
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
index 85605a2fc42..6b8407c571a 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/convert_ctor.pass.cpp
@@ -34,7 +34,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<B> d2;
     std::default_delete<A> d1 = d2;
@@ -44,4 +44,6 @@ int main()
     d1(p);
     assert(A::count == 0);
     assert(B::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
index c0a10e5e3eb..e7cbeaba5e0 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/default.pass.cpp
@@ -23,11 +23,13 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A> d;
     A* p = new A;
     assert(A::count == 1);
     d(p);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
index b09640215a2..75f02d7c6c6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/incomplete.fail.cpp
@@ -17,9 +17,11 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A> d;
     A* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
index d03468c0380..3bffeb57694 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt/void.fail.cpp
@@ -15,9 +15,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::default_delete<const void> d;
     const void* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
index 699d20ed4f7..4a2bb5f7da7 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.fail.cpp
@@ -24,8 +24,10 @@ struct B
 {
 };
 
-int main()
+int main(int, char**)
 {
     std::default_delete<B[]> d2;
     std::default_delete<A[]> d1 = d2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
index c2bfd31de1c..14e210598c1 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/convert_ctor.pass.cpp
@@ -19,9 +19,11 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::default_delete<int[]> d1;
     std::default_delete<const int[]> d2 = d1;
     ((void)d2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
index 246cf9d8dc5..9b220462b67 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/default.pass.cpp
@@ -25,11 +25,13 @@ struct A
 
 int A::count = 0;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A[]> d;
     A* p = new A[3];
     assert(A::count == 3);
     d(p);
     assert(A::count == 0);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
index 48ac045526e..54fe0fcf793 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.dflt1/incomplete.fail.cpp
@@ -17,9 +17,11 @@
 
 struct A;
 
-int main()
+int main(int, char**)
 {
     std::default_delete<A[]> d;
     A* p = 0;
     d(p);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.dltr/unique.ptr.dltr.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
index 774bc62d21b..52c399e64f7 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/cmp_nullptr.pass.cpp
@@ -40,7 +40,7 @@
 
 void do_nothing(int*) {}
 
-int main()
+int main(int, char**)
 {
     const std::unique_ptr<int> p1(new int(1));
     assert(!(p1 == nullptr));
@@ -65,4 +65,6 @@ int main()
     assert(!(nullptr > p2));
     assert( (p2 >= nullptr));
     assert( (nullptr >= p2));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
index e1f3e762d69..ce83b575031 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/eq.pass.cpp
@@ -44,7 +44,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const std::unique_ptr<A, Deleter<A> > p1(new A);
@@ -82,4 +82,6 @@ int main()
     assert(p1 == p2);
     assert(!(p1 != p2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
index 167dd7826c5..5fad4beb6c6 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/rel.pass.cpp
@@ -52,7 +52,7 @@ struct B
 
 int B::count = 0;
 
-int main()
+int main(int, char**)
 {
     {
     const std::unique_ptr<A, Deleter<A> > p1(new A);
@@ -96,4 +96,6 @@ int main()
     assert((p1 < p2) == !(p1 <= p2));
     assert((p1 < p2) == !(p1 >= p2));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
index 67cb170e4f9..4e45bbaef35 100644
--- a/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
+++ b/libcxx/test/std/utilities/smartptr/unique.ptr/unique.ptr.special/swap.pass.cpp
@@ -44,7 +44,7 @@ private:
 
 };
 
-int main()
+int main(int, char**)
 {
     {
     A* p1 = new A(1);
@@ -98,4 +98,6 @@ int main()
         std::swap(p, p2);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
index 8219296523b..ee6405bde1e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/char_ptr_ctor.pass.cpp
@@ -46,7 +46,7 @@ void test_char_pointer_ctor()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_char_pointer_ctor<0>();
     test_char_pointer_ctor<1>();
@@ -57,4 +57,6 @@ int main()
     test_char_pointer_ctor<64>();
     test_char_pointer_ctor<65>();
     test_char_pointer_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
index 0c88ba36ab6..bb5de6b18c7 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/default.pass.cpp
@@ -35,7 +35,7 @@ void test_default_ctor()
 }
 
 
-int main()
+int main(int, char**)
 {
     test_default_ctor<0>();
     test_default_ctor<1>();
@@ -46,4 +46,6 @@ int main()
     test_default_ctor<64>();
     test_default_ctor<65>();
     test_default_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
index f5052b5efbb..453db91f29d 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/string_ctor.pass.cpp
@@ -74,7 +74,7 @@ void test_string_ctor()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_string_ctor<0>();
     test_string_ctor<1>();
@@ -85,4 +85,6 @@ int main()
     test_string_ctor<64>();
     test_string_ctor<65>();
     test_string_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
index a09ce57e346..4697d8bd380 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.cons/ull_ctor.pass.cpp
@@ -39,7 +39,7 @@ void test_val_ctor()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_val_ctor<0>();
     test_val_ctor<1>();
@@ -50,4 +50,6 @@ int main()
     test_val_ctor<64>();
     test_val_ctor<65>();
     test_val_ctor<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
index 95347a2bc53..dfac9d94af7 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.hash/bitset.pass.cpp
@@ -38,10 +38,12 @@ test()
     ((void)result); // Prevent unused warning
 }
 
-int main()
+int main(int, char**)
 {
     test<0>();
     test<10>();
     test<100>();
     test<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
index 05d286f9058..a499b66fdb5 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.hash/enabled_hash.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
   {
     test_hash_enabled_for_type<std::bitset<0> >();
@@ -25,4 +25,6 @@ int main() {
     test_hash_enabled_for_type<std::bitset<1024> >();
     test_hash_enabled_for_type<std::bitset<100000> >();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
index 4ac3bae75a8..fe9e0e0a363 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/all.pass.cpp
@@ -28,7 +28,7 @@ void test_all()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_all<0>();
     test_all<1>();
@@ -39,4 +39,6 @@ int main()
     test_all<64>();
     test_all<65>();
     test_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
index 0483a04ffa2..95b640178b9 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/any.pass.cpp
@@ -31,7 +31,7 @@ void test_any()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_any<0>();
     test_any<1>();
@@ -42,4 +42,6 @@ int main()
     test_any<64>();
     test_any<65>();
     test_any<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
index 9b66e93e25f..5b04666bc2a 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/count.pass.cpp
@@ -42,7 +42,7 @@ void test_count()
     assert(c1 == c2);
 }
 
-int main()
+int main(int, char**)
 {
     test_count<0>();
     test_count<1>();
@@ -53,4 +53,6 @@ int main()
     test_count<64>();
     test_count<65>();
     test_count<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
index b3f515c0c3f..14bd9eadf98 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_all.pass.cpp
@@ -40,7 +40,7 @@ void test_flip_all()
         assert(v2[i] == ~v1[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_flip_all<0>();
     test_flip_all<1>();
@@ -51,4 +51,6 @@ int main()
     test_flip_all<64>();
     test_flip_all<65>();
     test_flip_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
index 96569e565e6..235b7e1a7ae 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/flip_one.pass.cpp
@@ -58,7 +58,7 @@ void test_flip_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_flip_one<0>(true);
     test_flip_one<1>(true);
@@ -69,4 +69,6 @@ int main()
     test_flip_one<64>(false);
     test_flip_one<65>(false);
     test_flip_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
index fb68df5aa38..a6eea145007 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/index.pass.cpp
@@ -60,7 +60,7 @@ void test_index_const()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_index_const<0>();
     test_index_const<1>();
@@ -71,4 +71,6 @@ int main()
     test_index_const<64>();
     test_index_const<65>();
     test_index_const<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
index 54a1a31c0db..9c6e28a8894 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/index_const.pass.cpp
@@ -42,7 +42,7 @@ void test_index_const()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_index_const<0>();
     test_index_const<1>();
@@ -53,4 +53,6 @@ int main()
     test_index_const<64>();
     test_index_const<65>();
     test_index_const<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
index 27a20b4f64a..59a7954a0df 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift.pass.cpp
@@ -41,7 +41,7 @@ void test_left_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_left_shift<0>();
     test_left_shift<1>();
@@ -52,4 +52,6 @@ int main()
     test_left_shift<64>();
     test_left_shift<65>();
     test_left_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
index c3becacd333..ad307ae8262 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/left_shift_eq.pass.cpp
@@ -46,7 +46,7 @@ void test_left_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_left_shift<0>();
     test_left_shift<1>();
@@ -57,4 +57,6 @@ int main()
     test_left_shift<64>();
     test_left_shift<65>();
     test_left_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
index d5004fbb686..2588ac60f7b 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/none.pass.cpp
@@ -31,7 +31,7 @@ void test_none()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_none<0>();
     test_none<1>();
@@ -42,4 +42,6 @@ int main()
     test_none<64>();
     test_none<65>();
     test_none<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
index 87c3efd1fc3..17b2d4293ac 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/not_all.pass.cpp
@@ -39,7 +39,7 @@ void test_not_all()
         assert(v2[i] == ~v1[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_not_all<0>();
     test_not_all<1>();
@@ -50,4 +50,6 @@ int main()
     test_not_all<64>();
     test_not_all<65>();
     test_not_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
index 38564bba5f8..8560be2467e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_and_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_and_eq()
         assert(v1[i] == (v3[i] && v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_and_eq<0>();
     test_op_and_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_and_eq<64>();
     test_op_and_eq<65>();
     test_op_and_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
index 7c428bce061..d2363023e62 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_eq_eq.pass.cpp
@@ -48,7 +48,7 @@ void test_equality()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_equality<0>();
     test_equality<1>();
@@ -59,4 +59,6 @@ int main()
     test_equality<64>();
     test_equality<65>();
     test_equality<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
index f96c77bc2e6..42d525e5b49 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_or_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_or_eq()
         assert(v1[i] == (v3[i] || v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_or_eq<0>();
     test_op_or_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_or_eq<64>();
     test_op_or_eq<65>();
     test_op_or_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
index 647c5c028be..44d58d8a155 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/op_xor_eq.pass.cpp
@@ -41,7 +41,7 @@ void test_op_xor_eq()
         assert(v1[i] == (v3[i] != v2[i]));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_xor_eq<0>();
     test_op_xor_eq<1>();
@@ -52,4 +52,6 @@ int main()
     test_op_xor_eq<64>();
     test_op_xor_eq<65>();
     test_op_xor_eq<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
index ae43bd7e99f..91041176ddb 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_all.pass.cpp
@@ -29,7 +29,7 @@ void test_reset_all()
         assert(!v[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_reset_all<0>();
     test_reset_all<1>();
@@ -40,4 +40,6 @@ int main()
     test_reset_all<64>();
     test_reset_all<65>();
     test_reset_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
index ec92f6656b3..1abb4914bfa 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/reset_one.pass.cpp
@@ -43,7 +43,7 @@ void test_reset_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_reset_one<0>(true);
     test_reset_one<1>(true);
@@ -54,4 +54,6 @@ int main()
     test_reset_one<64>(false);
     test_reset_one<65>(false);
     test_reset_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
index a94f9bf0921..e05c3316bb5 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift.pass.cpp
@@ -41,7 +41,7 @@ void test_right_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_right_shift<0>();
     test_right_shift<1>();
@@ -52,4 +52,6 @@ int main()
     test_right_shift<64>();
     test_right_shift<65>();
     test_right_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
index 387f68249e3..f23fbeebc87 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/right_shift_eq.pass.cpp
@@ -46,7 +46,7 @@ void test_right_shift()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_right_shift<0>();
     test_right_shift<1>();
@@ -57,4 +57,6 @@ int main()
     test_right_shift<64>();
     test_right_shift<65>();
     test_right_shift<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
index 68f8c58bb2c..ca4708cc43e 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/set_all.pass.cpp
@@ -28,7 +28,7 @@ void test_set_all()
         assert(v[i]);
 }
 
-int main()
+int main(int, char**)
 {
     test_set_all<0>();
     test_set_all<1>();
@@ -39,4 +39,6 @@ int main()
     test_set_all<64>();
     test_set_all<65>();
     test_set_all<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
index f660a440947..f723eebe085 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/set_one.pass.cpp
@@ -52,7 +52,7 @@ void test_set_one(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_set_one<0>(true);
     test_set_one<1>(true);
@@ -63,4 +63,6 @@ int main()
     test_set_one<64>(false);
     test_set_one<65>(false);
     test_set_one<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
index f1719ab2e41..41318d99eef 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/size.pass.cpp
@@ -18,7 +18,7 @@ void test_size()
     assert(v.size() == N);
 }
 
-int main()
+int main(int, char**)
 {
     test_size<0>();
     test_size<1>();
@@ -29,4 +29,6 @@ int main()
     test_size<64>();
     test_size<65>();
     test_size<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
index df3ee16be7e..5d566f5d0cf 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/test.pass.cpp
@@ -53,7 +53,7 @@ void test_test(bool test_throws)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test_test<0>(true);
     test_test<1>(true);
@@ -64,4 +64,6 @@ int main()
     test_test<64>(false);
     test_test<65>(false);
     test_test<1000>(false);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
index d8979447296..3897e10375f 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_string.pass.cpp
@@ -153,7 +153,7 @@ void test_to_string()
 }
 }
 
-int main()
+int main(int, char**)
 {
     test_to_string<0>();
     test_to_string<1>();
@@ -164,4 +164,6 @@ int main()
     test_to_string<64>();
     test_to_string<65>();
     test_to_string<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
index 1ea9b0f81f1..c43ef90aeef 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ullong.pass.cpp
@@ -44,7 +44,7 @@ void test_to_ullong()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //     test_to_ullong<0>();
     test_to_ullong<1>();
@@ -55,4 +55,6 @@ int main()
     test_to_ullong<64>();
     test_to_ullong<65>();
     test_to_ullong<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
index 71910f322b2..c6cf6b19a18 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.members/to_ulong.pass.cpp
@@ -46,7 +46,7 @@ void test_to_ulong()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_to_ulong<0>();
     test_to_ulong<1>();
@@ -57,4 +57,6 @@ int main()
     test_to_ulong<64>();
     test_to_ulong<65>();
     test_to_ulong<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
index af69d3951b7..21d5d08058c 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_and.pass.cpp
@@ -39,7 +39,7 @@ void test_op_and()
     assert((v1 & v2) == (v3 &= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_and<0>();
     test_op_and<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_and<64>();
     test_op_and<65>();
     test_op_and<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
index 8d9b2bdfb29..4a71385a941 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_not.pass.cpp
@@ -39,7 +39,7 @@ void test_op_not()
     assert((v1 ^ v2) == (v3 ^= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_not<0>();
     test_op_not<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_not<64>();
     test_op_not<65>();
     test_op_not<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
index c2cada15ea1..bc4847c19e4 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/op_or.pass.cpp
@@ -39,7 +39,7 @@ void test_op_or()
     assert((v1 | v2) == (v3 |= v2));
 }
 
-int main()
+int main(int, char**)
 {
     test_op_or<0>();
     test_op_or<1>();
@@ -50,4 +50,6 @@ int main()
     test_op_or<64>();
     test_op_or<65>();
     test_op_or<1000>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
index 714fcd3ed2f..9abe19c7c87 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_in.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream in("01011010");
     std::bitset<8> b;
     in >> b;
     assert(b.to_ulong() == 0x5A);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
index 06a36604ac4..2c4ce1e4881 100644
--- a/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/bitset.operators/stream_out.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::bitset<8> b(0x5A);
     os << b;
     assert(os.str() == "01011010");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/template.bitset/includes.pass.cpp b/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
index c98b150e792..90695ed3dcc 100644
--- a/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
+++ b/libcxx/test/std/utilities/template.bitset/includes.pass.cpp
@@ -12,7 +12,7 @@
 
 template <class> void test_typedef() {}
 
-int main()
+int main(int, char**)
 {
   { // test for <string>
     std::string s; ((void)s);
@@ -24,4 +24,6 @@ int main()
     test_typedef<std::ostream>();
     test_typedef<std::iostream>();
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
index 3fa04b77999..ac29fd78180 100644
--- a/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
+++ b/libcxx/test/std/utilities/time/date.time/ctime.pass.cpp
@@ -29,7 +29,7 @@
 #pragma GCC diagnostic ignored "-Wformat-zero-length"
 #endif
 
-int main()
+int main(int, char**)
 {
     std::clock_t c = 0;
     std::size_t s = 0;
@@ -60,4 +60,6 @@ int main()
     static_assert((std::is_same<decltype(std::localtime(&t)), std::tm*>::value), "");
 #endif
     static_assert((std::is_same<decltype(std::strftime(str,s,"",&tm)), std::size_t>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/days.pass.cpp b/libcxx/test/std/utilities/time/days.pass.cpp
index a22f97b8f52..43b53ea33cb 100644
--- a/libcxx/test/std/utilities/time/days.pass.cpp
+++ b/libcxx/test/std/utilities/time/days.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::days D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 25, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<24>, std::chrono::hours::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/hours.pass.cpp b/libcxx/test/std/utilities/time/hours.pass.cpp
index e04888f2e2a..97fc2621b6a 100644
--- a/libcxx/test/std/utilities/time/hours.pass.cpp
+++ b/libcxx/test/std/utilities/time/hours.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::hours D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 22, "");
     static_assert((std::is_same<Period, std::ratio<3600> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/microseconds.pass.cpp b/libcxx/test/std/utilities/time/microseconds.pass.cpp
index 20e12a9a288..ded1c22fe14 100644
--- a/libcxx/test/std/utilities/time/microseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/microseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::microseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 54, "");
     static_assert((std::is_same<Period, std::micro>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/milliseconds.pass.cpp b/libcxx/test/std/utilities/time/milliseconds.pass.cpp
index 6183b929f19..b1fe99e1209 100644
--- a/libcxx/test/std/utilities/time/milliseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/milliseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::milliseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 44, "");
     static_assert((std::is_same<Period, std::milli>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/minutes.pass.cpp b/libcxx/test/std/utilities/time/minutes.pass.cpp
index 413d8cd6f69..23f0bf2877d 100644
--- a/libcxx/test/std/utilities/time/minutes.pass.cpp
+++ b/libcxx/test/std/utilities/time/minutes.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::minutes D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 28, "");
     static_assert((std::is_same<Period, std::ratio<60> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/months.pass.cpp b/libcxx/test/std/utilities/time/months.pass.cpp
index ff40823f1ea..b14b2fab533 100644
--- a/libcxx/test/std/utilities/time/months.pass.cpp
+++ b/libcxx/test/std/utilities/time/months.pass.cpp
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::months D;
     typedef D::rep Rep;
@@ -25,4 +25,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 20, "");
     static_assert(std::is_same_v<Period, std::ratio_divide<std::chrono::years::period, std::ratio<12>>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/nanoseconds.pass.cpp b/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
index c14389da728..d58a375c2a5 100644
--- a/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/nanoseconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::nanoseconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 63, "");
     static_assert((std::is_same<Period, std::nano>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/seconds.pass.cpp b/libcxx/test/std/utilities/time/seconds.pass.cpp
index bd2d6d2b3f5..45a3f1d8e7f 100644
--- a/libcxx/test/std/utilities/time/seconds.pass.cpp
+++ b/libcxx/test/std/utilities/time/seconds.pass.cpp
@@ -14,7 +14,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::seconds D;
     typedef D::rep Rep;
@@ -23,4 +23,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 34, "");
     static_assert((std::is_same<Period, std::ratio<1> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
index 3a3978cb082..5c945fab75e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
@@ -42,4 +42,6 @@ int main()
         day day(i);
         assert(static_cast<unsigned>(day) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
index c53af65112e..f5323f65956 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(--(std::declval<day&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(day--) == i - 1);
         assert(static_cast<unsigned>(day)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
index b26d2285aa4..0be8c847f30 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(++(std::declval<day&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(day++) == i + 1);
         assert(static_cast<unsigned>(day)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
index 8a04298ab3c..131df7533c6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     ASSERT_NOEXCEPT(                std::declval<const day>().ok());
@@ -33,4 +33,6 @@ int main()
         assert(day{i}.ok());
     for (unsigned i = 32; i <= 255; ++i)
         assert(!day{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
index 42f12af552e..d182d6c926f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -53,4 +53,6 @@ int main()
         assert(static_cast<unsigned>(day -= days{12}) == i + 10);
         assert(static_cast<unsigned>(day)             == i + 10);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
index 6b8a4277272..75bc4cf529a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/comparisons.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
@@ -40,4 +40,6 @@ int main()
     for (unsigned i = 1; i < 10; ++i)
         for (unsigned j = 1; j < 10; ++j)
             assert(testComparisons6Values<day>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
index 36352fa35d6..6331bcf1b23 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
     day d1 = 4d; // expected-error-re {{no matching literal operator for call to 'operator""d' {{.*}}}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
index b3febd4ebe2..a887736f6e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/literals.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     using namespace std::chrono;
@@ -43,4 +43,6 @@ int main()
     assert (d1 == std::chrono::day(4));
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
index 4953d1afe4e..e8ade305adc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/minus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -54,4 +54,6 @@ int main()
         assert(static_cast<unsigned>(d1) == 12 - i);
         assert(off.count() == static_cast<int>(12 - i)); // days is signed
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
index 10cec0a62d8..e219c7d3c7a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/plus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using day  = std::chrono::day;
     using days = std::chrono::days;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<unsigned>(d1) == i + 12);
         assert(static_cast<unsigned>(d2) == i + 12);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
index ad3d4f3f9e6..23ce736c61d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/time.cal.day.nonmembers/streaming.pass.cpp
@@ -48,8 +48,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using day = std::chrono::day;
    std::cout << day{1};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
index d437a6ae3f4..3c26c57535f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.day/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day = std::chrono::day;
 
     static_assert(std::is_trivially_copyable_v<day>, "");
     static_assert(std::is_standard_layout_v<day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
index 10396919bd4..084a6aa8dc5 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.last/types.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using last_spec = std::chrono::last_spec;
 
@@ -29,4 +29,6 @@ int main()
 
     static_assert(std::is_trivially_copyable_v<last_spec>, "");
     static_assert(std::is_standard_layout_v<last_spec>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
index f3dadd2f6b0..48642987a7c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ctor.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -43,4 +43,6 @@ int main()
     static_assert( md1.month() == std::chrono::January, "");
     static_assert( md1.day()   == day{4},               "");
     static_assert( md1.ok(),                            "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
index c9c247d508f..7137433a9fb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month_day = std::chrono::month_day;
@@ -34,4 +34,6 @@ int main()
         month_day md(std::chrono::March, day{i});
         assert( static_cast<unsigned>(md.day()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
index e1b46190f0a..b4744e6d4c7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         month_day md(month{i}, day{1});
         assert( static_cast<unsigned>(md.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
index 649f0996867..5e4c0082f5f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.members/ok.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -51,4 +51,6 @@ int main()
 //  If the month is not ok, all the days are bad
     for (unsigned i = 1; i <= 35; ++i)
         assert(!(month_day{month{13}, day{i}}.ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
index c186f594c64..d7e535a72e7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day       = std::chrono::day;
     using month     = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
                 month_day{month{2}, day{j}},
                 i == j, i < j )));
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
index dbebdfa7d0e..8eef5f03095 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/time.cal.md.nonmembers/streaming.pass.cpp
@@ -31,10 +31,12 @@
 #include <iostream>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
     using month     = std::chrono::month;
     using day       = std::chrono::day;
     std::cout << month_day{month{1}, day{1}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
index ba7c336a634..507855a990f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.md/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
 
     static_assert(std::is_trivially_copyable_v<month_day>, "");
     static_assert(std::is_standard_layout_v<month_day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
index ba9eda73a4a..265e7be372d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/comparisons.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -39,4 +39,6 @@ int main()
     for (unsigned i = 1; i < 12; ++i)
         for (unsigned j = 1; j < 12; ++j)
             assert((testComparisons6Values<month_day_last>(month{i}, month{j})));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
index 4bf983f3b40..3696bb907d8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month     = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -37,4 +37,6 @@ int main()
     constexpr month_day_last md1{std::chrono::January};
     static_assert( md1.month() == std::chrono::January, "");
     static_assert( md1.ok(),                            "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
index b9945b6d88d..6bf75892da9 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month     = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -34,4 +34,6 @@ int main()
         month_day_last mdl(month{i});
         assert( static_cast<unsigned>(mdl.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
index 38c52e22958..730ab3b25d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -42,4 +42,6 @@ int main()
         month_day_last mdl{month{i}};
         assert(!mdl.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
index ebb91559854..1b4a8f108cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/streaming.pass.cpp
@@ -25,9 +25,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day_last = std::chrono::month_day_last;
     using month          = std::chrono::month;
     std::cout << month_day_last{month{1}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
index e3f02a88549..c6eebc42de1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mdlast/types.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_day_last = std::chrono::month_day_last;
 
     static_assert(std::is_trivially_copyable_v<month_day_last>, "");
     static_assert(std::is_standard_layout_v<month_day_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
index d0ed4d37d01..6800a03e18a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -42,4 +42,6 @@ int main()
         month m(i);
         assert(static_cast<unsigned>(m) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
index 2cab328cfcb..6d7edc508c1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -49,4 +49,6 @@ int main()
         assert(static_cast<unsigned>(month--) == i - 1);
         assert(static_cast<unsigned>(month)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
index 81162edf6ca..7bcd5bed716 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
     ASSERT_NOEXCEPT(++(std::declval<month&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<unsigned>(month++) == i + 1);
         assert(static_cast<unsigned>(month)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
index 7cb5edad47f..a001c74a3fa 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -34,4 +34,6 @@ int main()
         assert(month{i}.ok());
     for (unsigned i = 13; i <= 255; ++i)
         assert(!month{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
index 7ca4a6e5f4c..a792072afa2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -63,4 +63,6 @@ int main()
         assert(static_cast<unsigned>(month -= months{ 9}) == static_cast<unsigned>(exp));
         assert(static_cast<unsigned>(month)               == static_cast<unsigned>(exp));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
index aa37fde3b29..f69fec8aaac 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_comparisons.h"
 
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
@@ -43,4 +43,6 @@ int main()
     for (unsigned i = 1; i < 10; ++i)
         for (unsigned j = 10; j < 10; ++j)
             assert(testComparisons6Values<month>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
index 807cf29881b..9832fe37681 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/literals.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
     ASSERT_SAME_TYPE(const std::chrono::month, decltype(std::chrono::January));
@@ -83,4 +83,6 @@ int main()
     assert(static_cast<unsigned>(std::chrono::October)   == 10);
     assert(static_cast<unsigned>(std::chrono::November)  == 11);
     assert(static_cast<unsigned>(std::chrono::December)  == 12);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
index 291d299e3af..cda36412741 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/minus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -68,4 +68,6 @@ static_assert(testConstexpr<month, months>(), "");
         assert(static_cast<unsigned>(m1) == static_cast<unsigned>(exp));
 //          assert(off.count()               == static_cast<unsigned>(exp));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
index 87b39003b1e..58a951e1b0e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/plus.pass.cpp
@@ -43,7 +43,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month  = std::chrono::month;
     using months = std::chrono::months;
@@ -68,4 +68,6 @@ int main()
         assert(static_cast<unsigned>(m1) == exp);
         assert(static_cast<unsigned>(m2) == exp);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
index 5f3f3884f6b..1d3aa7ce4e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/time.cal.month.nonmembers/streaming.pass.cpp
@@ -45,8 +45,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using month = std::chrono::month;
    std::cout << month{1};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
index b3e5024656f..a6e67f10134 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.month/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month = std::chrono::month;
 
     static_assert(std::is_trivially_copyable_v<month>, "");
     static_assert(std::is_standard_layout_v<month>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
index 8d0b560b1fd..8804e71e3e8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ctor.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -42,4 +42,6 @@ int main()
     static_assert( md1.month() == std::chrono::January,                              "");
     static_assert( md1.weekday_indexed() == weekday_indexed{std::chrono::Friday, 4}, "");
     static_assert( md1.ok(),                                                         "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
index 99bdcb1607c..35e7c83c792 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -38,4 +38,6 @@ int main()
         month_weekday md(month{i}, weekday_indexed{Sunday, 1});
         assert( static_cast<unsigned>(md.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
index b4999652fd5..2ff1bf735f2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -47,4 +47,6 @@ int main()
 //  If the month is not ok, all the weekday_indexed are bad
     for (unsigned i = 1; i <= 10; ++i)
         assert(!(month_weekday{month{13}, weekday_indexed{Sunday, i}}.ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
index d80ae29d048..13a1bba53dd 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.members/weekday_indexed.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -39,4 +39,6 @@ int main()
         assert( static_cast<unsigned>(md.weekday_indexed().weekday() == Sunday));
         assert( static_cast<unsigned>(md.weekday_indexed().index() == i));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
index 64df8840e74..46f756de06c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -82,4 +82,6 @@ int main()
                 month_weekday{month{2}, weekday_indexed{weekday{i}, 2}},
                 month_weekday{month{2}, weekday_indexed{weekday{j}, 2}},
                 i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
index e7981b5713a..11a1d4ecd04 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/time.cal.mwd.nonmembers/streaming.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -32,4 +32,6 @@ int main()
     using weekday         = std::chrono::weekday;
 
     std::cout << month_weekday{month{1}, weekday_indexed{weekday{3}, 3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
index 67c3f17b946..bd4f4e1d492 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday = std::chrono::month_weekday;
 
     static_assert(std::is_trivially_copyable_v<month_weekday>, "");
     static_assert(std::is_standard_layout_v<month_weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
index fa5ca044358..d83bbe92f11 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ctor.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -56,4 +56,6 @@ int main()
     static_assert( mwdl3.month() == January,                         "");
     static_assert( mwdl3.weekday_last() == weekday_last{weekday{4}}, "");
     static_assert( mwdl3.ok(),                                       "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
index 3561651c28a..a32b0899615 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -38,4 +38,6 @@ int main()
         month_weekday_last mdl(month{i}, weekday_last{Tuesday});
         assert( static_cast<unsigned>(mdl.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
index 10245f938d6..02df5fbd22b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -48,4 +48,6 @@ int main()
         month_weekday_last mwdl{January, weekday_last{weekday{i}}};
         assert( mwdl.ok() == weekday_last{weekday{i}}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
index 4afa6cca734..4ecf6d24628 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.members/weekday_last.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday            = std::chrono::weekday;
@@ -40,4 +40,6 @@ int main()
         month_weekday_last mdl(January, weekday_last{weekday{i}});
         assert( static_cast<unsigned>(mdl.weekday_last().weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
index 4d0e935f11a..911693c25bf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/comparisons.pass.cpp
@@ -24,7 +24,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month              = std::chrono::month;
     using weekday_last       = std::chrono::weekday_last;
@@ -69,4 +69,6 @@ int main()
             month_weekday_last{month{1}, weekday_last{weekday{1}}},
             month_weekday_last{month{2}, weekday_last{weekday{2}}},
         false)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
index 2bf0e1ec43b..75654b1b3a2 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/time.cal.mwdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday_last = std::chrono::month_weekday_last;
     using month              = std::chrono::month;
@@ -33,4 +33,6 @@ int main()
     using weekday_last       = std::chrono::weekday_last;
 
     std::cout << month_weekday_last{month{1}, weekday_last{weekday{3}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
index 2271f42c031..2f2676d7a52 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.mwdlast/types.pass.cpp
@@ -17,10 +17,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday_last = std::chrono::month_weekday_last;
 
     static_assert(std::is_trivially_copyable_v<month_weekday_last>, "");
     static_assert(std::is_standard_layout_v<month_weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
index e51fb4fa47e..e9eb80bfd98 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day.pass.cpp
@@ -38,7 +38,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_day = std::chrono::month_day;
     using month     = std::chrono::month;
@@ -104,4 +104,6 @@ int main()
                 assert(md1 == md2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
index 27043b88c63..84c2c6eaa39 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_day_last.pass.cpp
@@ -46,7 +46,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month          = std::chrono::month;
     using month_day_last = std::chrono::month_day_last;
@@ -103,4 +103,6 @@ int main()
         }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
index 4dc6db768e2..60b788de1e4 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday.pass.cpp
@@ -44,7 +44,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday   = std::chrono::month_weekday;
     using month           = std::chrono::month;
@@ -111,4 +111,6 @@ int main()
                     assert(mwd1 == mwd2);
                 }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
index 25d25b26d9b..07e5d8d75d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/month_weekday_last.pass.cpp
@@ -36,7 +36,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month_weekday      = std::chrono::month_weekday;
     using month              = std::chrono::month;
@@ -103,4 +103,6 @@ int main()
                 assert(mwd1 == mwd2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
index 6ef320ebb79..ba2b5c187f6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month.pass.cpp
@@ -25,7 +25,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -64,4 +64,6 @@ int main()
                 assert(static_cast<unsigned>(ym.month()) == j);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
index a8df7009632..a5aa4d0ef59 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day.pass.cpp
@@ -42,7 +42,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -187,4 +187,6 @@ int main()
                 }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
index 2556bb93f36..fd55e38b4c4 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_day_last.pass.cpp
@@ -38,7 +38,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using month               = std::chrono::month;
     using year_month          = std::chrono::year_month;
@@ -121,4 +121,6 @@ int main()
                 assert(ymdl1 == ymdl2);
             }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
index af27c945e09..4e71435805a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday.pass.cpp
@@ -37,7 +37,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using year_month         = std::chrono::year_month;
@@ -141,4 +141,6 @@ int main()
                         assert(ymd1 == ymd2);
                     }
      }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
index ff467aa60c3..62b1f46765c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.operators/year_month_weekday_last.pass.cpp
@@ -39,7 +39,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year_month         = std::chrono::year_month;
     using year               = std::chrono::year;
@@ -149,4 +149,6 @@ int main()
                     assert(ymwdl1 == ymwdl2);
                 }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
index b9facef63e7..4a64b932b68 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ctor.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday  = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -57,4 +57,6 @@ int main()
         weekday_indexed wdi(std::chrono::Tuesday, i);
         assert(!wdi.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
index 043a98accf5..4942f716480 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/index.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -34,4 +34,6 @@ int main()
         weekday_indexed wdi(weekday{2}, i);
         assert( static_cast<unsigned>(wdi.index()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
index 1cdfb29c96e..a2b5b48e4fc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -45,4 +45,6 @@ int main()
 
 //  Not a valid weekday
     assert(!(weekday_indexed(weekday{9U}, 1).ok()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
index 47f50b6d672..e9c204d08b1 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -35,4 +35,6 @@ int main()
         weekday_indexed wdi(weekday{i}, 2);
         assert( static_cast<unsigned>(wdi.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
index 963f9f15ec8..104c59abf78 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_indexed = std::chrono::weekday_indexed;
@@ -44,4 +44,6 @@ int main()
     static_assert( (weekday_indexed{weekday{1}, 2} != weekday_indexed{weekday{1}, 1}), "");
     static_assert(!(weekday_indexed{weekday{1}, 2} == weekday_indexed{weekday{2}, 2}),  "");
     static_assert( (weekday_indexed{weekday{1}, 2} != weekday_indexed{weekday{2}, 2}),  "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
index 810b2cb0c49..5052a182458 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/time.cal.wdidx.nonmembers/streaming.pass.cpp
@@ -26,10 +26,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_indexed = std::chrono::weekday_indexed;
     using weekday         = std::chrono::weekday;
 
     std::cout << weekday_indexed{weekday{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
index 74634da8a58..260b50f465d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdidx/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_indexed = std::chrono::weekday_indexed;
 
     static_assert(std::is_trivially_copyable_v<weekday_indexed>, "");
     static_assert(std::is_standard_layout_v<weekday_indexed>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
index f7fa6632041..a569144d068 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -43,4 +43,6 @@ int main()
         weekday_last wdl{weekday{i}};
         assert(wdl.weekday() == weekday{i});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
index d708a812463..eb0636aa9cf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -33,4 +33,6 @@ int main()
 
     for (unsigned i = 0; i <= 255; ++i)
         assert(weekday_last{weekday{i}}.ok() == weekday{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
index 48767b3b86e..c5eb6e13201 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -29,4 +29,6 @@ int main()
 
     for (unsigned i = 0; i <= 255; ++i)
         assert(weekday_last{weekday{i}}.weekday() == weekday{i});
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
index 1a9fc97eb51..c5ca36e8288 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday      = std::chrono::weekday;
     using weekday_last = std::chrono::weekday_last;
@@ -39,4 +39,6 @@ int main()
     for (unsigned i = 0; i < 6; ++i)
         for (unsigned j = 0; j < 6; ++j)
             assert(testComparisons2Values<weekday_last>(weekday{i}, weekday{j}));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
index efb59847255..85a40a3dc4c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/time.cal.wdlast.nonmembers/streaming.pass.cpp
@@ -24,10 +24,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using weekday_last = std::chrono::weekday_last;
    using weekday      = std::chrono::weekday;
 
    std::cout << weekday_last{weekday{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
index c986f99c332..ff9d54f88da 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.wdlast/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday_last = std::chrono::weekday_last;
 
     static_assert(std::is_trivially_copyable_v<weekday_last>, "");
     static_assert(std::is_standard_layout_v<weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
index ee241c8e7c9..06656fb442a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using local_days = std::chrono::local_days;
     using days       = std::chrono::days;
@@ -69,4 +69,6 @@ int main()
     assert( wd.ok());
     assert(static_cast<unsigned>(wd) == 3);
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
index 9ec3afb2144..470b9d79d23 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -47,4 +47,6 @@ int main()
     }
 
 // TODO - sys_days and local_days ctor tests
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
index 920b53e783c..e00184a9915 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ctor.sys_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using sys_days  = std::chrono::sys_days;
     using days      = std::chrono::days;
@@ -69,4 +69,6 @@ int main()
     assert( wd.ok());
     assert(static_cast<unsigned>(wd) == 3);
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
index c8b023a37c5..d574e1db9b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/decrement.pass.cpp
@@ -31,7 +31,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     ASSERT_NOEXCEPT(--(std::declval<weekday&>())  );
@@ -49,4 +49,6 @@ int main()
         assert((static_cast<unsigned>(wd--) == euclidian_subtraction<unsigned, 0, 6>(i, 1)));
         assert((static_cast<unsigned>(wd)   == euclidian_subtraction<unsigned, 0, 6>(i, 2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
index d9239ff8f90..bb62e0120ef 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/increment.pass.cpp
@@ -31,7 +31,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     ASSERT_NOEXCEPT(++(std::declval<weekday&>())  );
@@ -49,4 +49,6 @@ int main()
         assert((static_cast<unsigned>(wd++) == euclidian_addition<unsigned, 0, 6>(i, 1)));
         assert((static_cast<unsigned>(wd)   == euclidian_addition<unsigned, 0, 6>(i, 2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
index f8bd9d43a25..f2f6e2e9802 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -34,4 +34,6 @@ int main()
         assert(weekday{i}.ok());
     for (unsigned i = 7; i <= 255; ++i)
         assert(!weekday{i}.ok());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
index aa0f3f7e59e..d7d2d6faf30 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/operator[].pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "../../euclidian.h"
 
-int main()
+int main(int, char**)
 {
     using weekday         = std::chrono::weekday;
     using weekday_last    = std::chrono::weekday_last;
@@ -55,4 +55,6 @@ int main()
         assert(wdi.index() == j);
         assert(wdi.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
index e0963540cf2..d99b0349399 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.members/plus_minus_equal.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     using days    = std::chrono::days;
@@ -59,4 +59,6 @@ int main()
         assert((static_cast<unsigned>(wd -= days{4}) == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
         assert((static_cast<unsigned>(wd)            == euclidian_subtraction<unsigned, 0, 6>(i, 4)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
index c042ac14778..982b3bccbc6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/comparisons.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
@@ -38,4 +38,6 @@ int main()
     for (unsigned i = 0; i < 6; ++i)
         for (unsigned j = 0; j < 6; ++j)
             assert(testComparisons2Values<weekday>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
index 8f713aad280..7529864a5bb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/literals.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
 
     ASSERT_SAME_TYPE(const std::chrono::weekday, decltype(std::chrono::Sunday));
@@ -58,4 +58,6 @@ int main()
     assert(static_cast<unsigned>(std::chrono::Thursday)  ==  4);
     assert(static_cast<unsigned>(std::chrono::Friday)    ==  5);
     assert(static_cast<unsigned>(std::chrono::Saturday)  ==  6);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
index 2bf0ed78995..f296fc6d68e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/minus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday  = std::chrono::weekday;
     using days     = std::chrono::days;
@@ -72,4 +72,6 @@ int main()
             assert(weekday{i} + d == weekday{j});
         }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
index 287834cd7e8..78d332b96cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/plus.pass.cpp
@@ -44,7 +44,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
     using days    = std::chrono::days;
@@ -66,4 +66,6 @@ int main()
             assert((static_cast<unsigned>(wd1) == euclidian_addition<unsigned, 0, 6>(i, j)));
             assert((static_cast<unsigned>(wd2) == euclidian_addition<unsigned, 0, 6>(i, j)));
         }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
index aef5a82e78d..43825b60e99 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/time.cal.weekday.nonmembers/streaming.pass.cpp
@@ -47,9 +47,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using weekday = std::chrono::weekday;
 
    std::cout << weekday{3};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
index ed355b02515..7264a210f59 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.weekday/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using weekday = std::chrono::weekday;
 
     static_assert(std::is_trivially_copyable_v<weekday>, "");
     static_assert(std::is_standard_layout_v<weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
index 5f8b4660a24..e46b5563064 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ctor.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -42,4 +42,6 @@ int main()
         year year(i);
         assert(static_cast<int>(year) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
index e8473bf9810..893c48aab47 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/decrement.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
     ASSERT_NOEXCEPT(--(std::declval<year&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<int>(year--) == i - 1);
         assert(static_cast<int>(year)   == i - 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
index 759fb66617b..ef2a6f3fbee 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/increment.pass.cpp
@@ -30,7 +30,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
     ASSERT_NOEXCEPT(++(std::declval<year&>())  );
@@ -48,4 +48,6 @@ int main()
         assert(static_cast<int>(year++) == i + 1);
         assert(static_cast<int>(year)   == i + 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
index b1785b86c59..37031dbbabc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/is_leap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -49,4 +49,6 @@ int main()
     assert(!year{ 2003}.is_leap());
     assert( year{ 2004}.is_leap());
     assert(!year{ 2100}.is_leap());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
index dfc2ad3ffe4..f56ee34d598 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/ok.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -49,4 +49,6 @@ int main()
     assert(year{ 20001}.ok());
 
     static_assert(!year{-32768}.ok(), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
index 65b1494587b..0adb0f9fe58 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
 
@@ -46,4 +46,6 @@ int main()
         assert(static_cast<int>(+year) ==  i);
         assert(static_cast<int>(-year) == -i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
index a00a36f2dca..b79713ed1c8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.members/plus_minus_equal.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -53,4 +53,6 @@ int main()
         assert(static_cast<int>(year -= years{ 9}) == i +  1);
         assert(static_cast<int>(year)              == i +  1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
index 8d675f4db39..9e84fe36ee0 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_comparisons.h"
 
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
@@ -43,4 +43,6 @@ int main()
     for (int i = 1; i < 10; ++i)
         for (int j = 1; j < 10; ++j)
             assert(testComparisons6Values<year>(i, j));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
index c6138c7af1c..50c7b7bc0a6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using std::chrono::year;
     year d1 = 1234y; // expected-error-re {{no matching literal operator for call to 'operator""y' {{.*}}}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
index 6ebd0e66fdd..a2bec73e696 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/literals.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     using namespace std::chrono;
@@ -40,4 +40,6 @@ int main()
     std::chrono::year y1 = 2020y;
     assert (y1 == std::chrono::year(2020));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
index 3e3e0b77db4..f112345c0ad 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/minus.pass.cpp
@@ -37,7 +37,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -58,4 +58,6 @@ int main()
         assert(static_cast<int>(y1) == 1223 - i);
         assert(ys1.count()          == 1223 - i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
index 15c713defb4..d73f6fc88b3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/plus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool testConstexpr()
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year  = std::chrono::year;
     using years = std::chrono::years;
@@ -55,4 +55,6 @@ int main()
         assert(static_cast<int>(y1) == i + 1223);
         assert(static_cast<int>(y2) == i + 1223);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
index 2c52cde0a43..1b278f2b903 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/time.cal.year.nonmembers/streaming.pass.cpp
@@ -46,9 +46,11 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
    using year = std::chrono::year;
 
    std::cout << year{2018};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
index 10bea23a035..2acb0f104d3 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.year/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year = std::chrono::year;
 
     static_assert(std::is_trivially_copyable_v<year>, "");
     static_assert(std::is_standard_layout_v<year>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
index 090a1ac212c..1c05cf7a6b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ctor.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
     static_assert( ym2.year()  == year{2018}, "");
     static_assert( ym2.month() == month{},    "");
     static_assert(!ym2.ok(),                  "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
index 97334b20503..7e0cd17f467 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         year_month ym(year{1234}, month{i});
         assert( static_cast<unsigned>(ym.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
index 54e67dff9a3..463289ee43f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -46,4 +46,6 @@ int main()
         year_month ym{year{i}, January};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
index 76f3b3355d2..a403462ff79 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using months     = std::chrono::months;
@@ -60,4 +60,6 @@ int main()
         assert(static_cast<unsigned>((ym             ).month()) == i + 1);
         assert(ym.year() == y);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
index 05cd60844d9..adf08fc24b8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using month      = std::chrono::month;
     using year       = std::chrono::year;
@@ -61,4 +61,6 @@ int main()
         assert(static_cast<int>((ym            ).year()) == i + 1);
         assert(ym.month() == m);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
index e8476b04280..024f3140425 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -35,4 +35,6 @@ int main()
         year_month ym(year{i}, month{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
index e1ab033c7c7..d102b0a5620 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using month      = std::chrono::month;
@@ -65,4 +65,6 @@ int main()
             year_month{year{i}, std::chrono::January},
             year_month{year{j}, std::chrono::January},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
index 2999560f16f..d7756d10d25 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/minus.pass.cpp
@@ -29,7 +29,7 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using years      = std::chrono::years;
@@ -86,4 +86,6 @@ int main()
 //  TODO: different year
 
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
index dc721adeedb..5698e724470 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year       = std::chrono::year;
     using years      = std::chrono::years;
@@ -102,4 +102,6 @@ int main()
         assert(ym1 == ym2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
index e75fc21bf88..43af6c2f719 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/time.cal.ym.nonmembers/streaming.pass.cpp
@@ -46,11 +46,13 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month = std::chrono::year_month;
     using year       = std::chrono::year;
     using month      = std::chrono::month;
 
     std::cout << year_month{year{2018}, month{3}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
index a3b9999f8fd..2e88c6bb6b6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ym/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month = std::chrono::year_month;
 
     static_assert(std::is_trivially_copyable_v<year_month>, "");
     static_assert(std::is_standard_layout_v<year_month>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
index 9cebaa6836a..274cb6a266f 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using day            = std::chrono::day;
@@ -81,4 +81,6 @@ int main()
     assert( ymd.month() == std::chrono::November);
     assert( ymd.day()   == day{29});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
index a5818849add..fdef9517e4a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -52,4 +52,6 @@ int main()
     static_assert( ym1.day()   == day{12},    "");
     static_assert( ym1.ok(),                  "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
index 7344c10c1ad..433468477d5 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.sys_days.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using day            = std::chrono::day;
@@ -80,4 +80,6 @@ int main()
     assert( ymd.month() == std::chrono::November);
     assert( ymd.day()   == day{29});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
index 913b403952b..d4e8fc83d5b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ctor.year_month_day_last.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
     assert( ymd.day()   == day{28});
     assert( ymd.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
index 12e1515b171..9a068737ddc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ymd(year{1234}, month{2}, day{i});
         assert( static_cast<unsigned>(ymd.day()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
index 8c091d05165..f1dd2e6893a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ymd(year{1234}, month{i}, day{12});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
index edb55f58b4c..cab639b820a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -92,4 +92,6 @@ int main()
         year_month_day ym{year{i}, January, day{12}};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
index 02212dc9094..038d21c4670 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.local_days.pass.cpp
@@ -44,7 +44,7 @@ void RunTheExample()
     static_assert(year_month_day{local_days{year{2017}/January/32}} == year{2017}/February/1);  
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -90,4 +90,5 @@ int main()
     assert( year_month_day{sd} == ymd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
index 5925cb0cb5c..a9568455085 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/op.sys_days.pass.cpp
@@ -44,7 +44,7 @@ void RunTheExample()
     static_assert(year_month_day{sys_days{year{2017}/January/32}} == year{2017}/February/1);  
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -90,4 +90,5 @@ int main()
     assert( year_month_day{sd} == ymd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
index 173b8b6a2fb..8530248d1d6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
         assert(ym.year() == y);
         assert(ym.day()  == d);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
index 1d995129152..ae134d1a240 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -66,4 +66,6 @@ int main()
         assert(ym.month() == m);
         assert(ym.day()   == d);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
index 465fa9d93db..fc5a4072493 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_day ym(year{i}, month{}, day{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
index 8d5bf89553c..0d15589252a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/comparisons.pass.cpp
@@ -29,7 +29,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using day        = std::chrono::day;
     using year       = std::chrono::year;
@@ -114,4 +114,6 @@ int main()
             year_month_day{year{i}, January, day{12}},
             year_month_day{year{j}, January, day{12}},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
index 4d5625ba739..3c921def3b8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/minus.pass.cpp
@@ -33,7 +33,7 @@ constexpr bool test_constexpr ()
         ;
 }
 
-int main()
+int main(int, char**)
 {
     using year           = std::chrono::year;
     using month          = std::chrono::month;
@@ -56,4 +56,6 @@ int main()
         assert(ym1.month() == January);
         assert(ym1.day() == day{10});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
index 2913eb23743..8d5e02543aa 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_day ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using day        = std::chrono::day;
     using year       = std::chrono::year;
@@ -108,4 +108,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
index cce42bc616d..47b6f02490d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/time.cal.ymd.nonmembers/streaming.pass.cpp
@@ -46,7 +46,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day = std::chrono::year_month_day;
     using year           = std::chrono::year;
@@ -54,4 +54,6 @@ int main()
     using day            = std::chrono::day;
 
     std::cout << year_month_day{year{2018}, month{3}, day{12}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
index c61d1c9960f..58acd143df9 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day = std::chrono::year_month_day;
 
     static_assert(std::is_trivially_copyable_v<year_month_day>, "");
     static_assert(std::is_standard_layout_v<year_month_day>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
index d27c3c67e5e..bd4729f6a0e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ctor.pass.cpp
@@ -27,7 +27,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -49,4 +49,6 @@ int main()
     static_assert( ymdl1.month()          == January,                 "");
     static_assert( ymdl1.month_day_last() == month_day_last{January}, "");
     static_assert( ymdl1.ok(),                                        "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
index 24682b6957f..2f0e2ba17a7 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/day.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -47,4 +47,6 @@ int main()
     assert((year_month_day_last{year{2019}, month_day_last{month{ 2}}}.day() == day{28}));
     assert((year_month_day_last{year{2020}, month_day_last{month{ 2}}}.day() == day{29}));
     assert((year_month_day_last{year{2021}, month_day_last{month{ 2}}}.day() == day{28}));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
index cf1024a8ce3..5b68aa1d95c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ymd(year{1234}, month_day_last{month{i}});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
index 5c99d947124..cca9026b650 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/month_day_last.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ymdl(year{1234}, month_day_last{month{i}});
         assert( static_cast<unsigned>(ymdl.month_day_last().month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
index bb4c410d449..d40de103c2a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
         year_month_day_last ym{year{i}, month_day_last{January}};
         assert( ym.ok() == year{i}.ok());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
index 83f8b70dc79..a96dff338be 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_local_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
index 9a32112c901..250ca0f1123 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/op_sys_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
index 2c4d1ff1f17..7091f64ea33 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -62,4 +62,6 @@ int main()
         assert(static_cast<unsigned>((ym             ).month()) == i + 1);
         assert(ym.year() == y);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
index 00335e15d54..3c1ad352737 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -61,4 +61,6 @@ int main()
         assert(static_cast<int>((ymdl            ).year()) == i + 1);
         assert(ymdl.month_day_last() == mdl);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
index 49387091d76..c0db150f96d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -34,4 +34,6 @@ int main()
         year_month_day_last ym(year{i}, month_day_last{month{}});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
index 9db4b6aa6d9..c56491f96cb 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/comparisons.pass.cpp
@@ -26,7 +26,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -83,4 +83,6 @@ int main()
             year_month_day_last{year{i}, month_day_last{January}},
             year_month_day_last{year{j}, month_day_last{January}},
             i == j, i < j )));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
index 7f5a796dfab..8ea3025d607 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/minus.pass.cpp
@@ -47,7 +47,7 @@ constexpr bool testConstexprMonths (std::chrono::year_month_day_last ymdl)
         ;
 }
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -87,4 +87,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
index c494620df6e..75cabbdcd28 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/plus.pass.cpp
@@ -63,7 +63,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_day_last ymdl)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month               = std::chrono::month;
@@ -118,4 +118,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
index 268eb88fe17..eca8d3d6851 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymdlast/time.cal.ymdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_day_last = std::chrono::year_month_day_last;
     using year                = std::chrono::year;
@@ -33,4 +33,6 @@ int main()
     using month_day_last      = std::chrono::month_day_last;
 
     std::cout << year_month_day_last{year{2018}, month_day_last{month{3}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
index 0eae24e459c..bb4e7d04405 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.local_days.pass.cpp
@@ -29,7 +29,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using days               = std::chrono::days;
@@ -91,4 +91,6 @@ int main()
     assert((ymwd.weekday_indexed() == weekday_indexed{std::chrono::Wednesday, 5}));
     assert( ymwd                   == year_month_weekday{local_days{ymwd}}); // round trip
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
index dab8b21577b..81030ff559d 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.pass.cpp
@@ -30,7 +30,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -60,4 +60,6 @@ int main()
     static_assert( ym1.weekday_indexed() == weekday_indexed{Tuesday, 1}, "");
     static_assert( ym1.ok(),                                             "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
index 96261c54e3c..5ae9900a983 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ctor.sys_days.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using days               = std::chrono::days;
@@ -90,4 +90,6 @@ int main()
     assert((ymwd.weekday_indexed() == weekday_indexed{std::chrono::Wednesday, 5}));
     assert( ymwd                   == year_month_weekday{sys_days{ymwd}}); // round trip
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
index 4c0bc13c186..ecbd8aec830 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/index.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{2}, i});
         assert(ymwd0.index() == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
index 0e2d41a771f..c300fd5d36a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_weekday ymd(year{1234}, month{i}, weekday_indexed{});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
index f66d6a083c4..7e8599e0509 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -71,4 +71,6 @@ int main()
         year_month_weekday ym{year{i}, January, weekday_indexed{Tuesday, 1}};
         assert((ym.ok() == year{i}.ok()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
index 788af653555..e86e5b0fa6e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.local_days.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -70,4 +70,5 @@ int main()
     assert( year_month_weekday{sd} == ymwd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
index 111cf5f38db..afb1d70148a 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/op.sys_days.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -70,4 +70,5 @@ int main()
     assert( year_month_weekday{sd} == ymwd); // and back
     }
 
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
index 7e20a8eb05a..fd53279ddde 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
         assert(ymwd.weekday()  == Tuesday);
         assert(ymwd.index()    == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
index 4deee9bc35d..cf229febe08 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -76,4 +76,6 @@ int main()
         assert(ymwd.weekday()  == Tuesday);
         assert(ymwd.index()    == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
index 1b9c8ad1041..dac1f7cc049 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday ymwd0(year{1234}, month{2}, weekday_indexed{weekday{i}, 1});
         assert(static_cast<unsigned>(ymwd0.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
index 4a9832323f1..f089a8cb93e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/weekday_indexed.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -41,4 +41,6 @@ int main()
         assert( static_cast<unsigned>(ymwd1.weekday_indexed().weekday()) == 2);
         assert( static_cast<unsigned>(ymwd1.weekday_indexed().index()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
index 8103c28aa60..1ead67570cf 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -36,4 +36,6 @@ int main()
         year_month_weekday ym(year{i}, month{1}, weekday_indexed{});
         assert( static_cast<int>(ym.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
index 847699b2516..5631127222b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -109,4 +109,6 @@ int main()
             year_month_weekday{year{i}, January, weekday_indexed{Tuesday, 1}},
             year_month_weekday{year{j}, January, weekday_indexed{Tuesday, 1}},
             i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
index ff472fdc6ce..47cfbea6a67 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/minus.pass.cpp
@@ -50,7 +50,7 @@ constexpr bool testConstexprMonths ()
 }
 
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -96,4 +96,6 @@ int main()
         assert(ym1.index()   == 2);
     }
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
index bc72d958ca0..29df4776e2b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/plus.pass.cpp
@@ -51,7 +51,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year               = std::chrono::year;
     using month              = std::chrono::month;
@@ -116,4 +116,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
index eb92cf05e47..411e4335fd0 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/time.cal.ymwd.nonmembers/streaming.pass.cpp
@@ -45,7 +45,7 @@
 #include <iostream>
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday = std::chrono::year_month_weekday;
     using year                = std::chrono::year;
@@ -53,4 +53,6 @@ int main()
     using weekday             = std::chrono::weekday;
 
     std::cout << year_month_weekday{year{2018}, month{3}, weekday{4}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
index 449098c4f18..76e2e0f237e 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwd/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday = std::chrono::year_month_weekday;
 
     static_assert(std::is_trivially_copyable_v<year_month_weekday>, "");
     static_assert(std::is_standard_layout_v<year_month_weekday>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
index 1db6850dbce..31d2e9ca706 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ctor.pass.cpp
@@ -28,7 +28,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -48,4 +48,6 @@ int main()
     static_assert( ym1.weekday_last() == weekday_last{Tuesday}, "");
     static_assert( ym1.ok(),                                    "");
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
index 7b95084b214..df62d010ab6 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/month.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymd(year{1234}, month{i}, weekday_last{weekday{}});
         assert( static_cast<unsigned>(ymd.month()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
index 1cffb4565b7..c18b926704c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/ok.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -69,4 +69,6 @@ int main()
         year_month_weekday_last ym{year{i}, January, weekday_last{Tuesday}};
         assert((ym.ok() == year{i}.ok()));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
index 83f8b70dc79..c663406ee43 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_local_days.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                = std::chrono::year;
     using month_day_last      = std::chrono::month_day_last;
@@ -57,4 +57,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+33)});
     }
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
index cc3da2992e8..cb75842c64c 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/op_sys_days.pass.cpp
@@ -22,7 +22,7 @@
 
 #include <iostream>
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -65,4 +65,6 @@ int main()
 
     assert(sd.time_since_epoch() == days{-(10957+35)});
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
index ad513c5d0cf..b2bb1361b6b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_month.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -71,4 +71,6 @@ int main()
         assert(ymwd.year()     == y);
         assert(ymwd.weekday()  == Tuesday);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
index 7d9255fe494..8ced182d6c8 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/plus_minus_equal_year.pass.cpp
@@ -32,7 +32,7 @@ constexpr bool testConstexpr(D d1)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -72,4 +72,6 @@ int main()
         assert(ymwd.month()    == January);
         assert(ymwd.weekday()  == Tuesday);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
index cc0521354f9..1de0b832309 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/weekday.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymwdl(year{1}, month{1}, weekday_last{weekday{i}});
         assert(static_cast<unsigned>(ymwdl.weekday()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
index 4011f0673ff..4e940791145 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.members/year.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -37,4 +37,6 @@ int main()
         year_month_weekday_last ymwdl(year{i}, month{1}, weekday_last{weekday{}});
         assert(static_cast<int>(ymwdl.year()) == i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
index a13b11f8c10..24074f33cbc 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/comparisons.pass.cpp
@@ -22,7 +22,7 @@
 #include "test_macros.h"
 #include "test_comparisons.h"
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -110,4 +110,6 @@ int main()
             year_month_weekday_last{year{i}, January, weekday_last{Tuesday}},
             year_month_weekday_last{year{j}, January, weekday_last{Tuesday}},
             i == j)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
index 20a58152f33..d58c461be8b 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/minus.pass.cpp
@@ -40,7 +40,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
     return true;
 }
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -89,4 +89,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
index 45dd7562dc0..fe246cf42ba 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/plus.pass.cpp
@@ -47,7 +47,7 @@ constexpr bool testConstexprMonths(std::chrono::year_month_weekday_last ym)
 }
 
 
-int main()
+int main(int, char**)
 {
     using year                    = std::chrono::year;
     using month                   = std::chrono::month;
@@ -112,4 +112,6 @@ int main()
     }
     }
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
index 6e4409c7138..cdfe55f1650 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/time.cal.ymwdlast.nonmembers/streaming.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday_last = std::chrono::year_month_weekday_last;
     using year                    = std::chrono::year;
@@ -34,4 +34,6 @@ int main()
     using weekday_last            = std::chrono::weekday_last;
 
     std::cout << year_month_weekday_last{year{2018}, month{3}, weekday_last{weekday{4}}};
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
index e0580fac76f..70dea7bf922 100644
--- a/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.cal/time.cal.ymwdlast/types.pass.cpp
@@ -16,10 +16,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using year_month_weekday_last = std::chrono::year_month_weekday_last;
 
     static_assert(std::is_trivially_copyable_v<year_month_weekday_last>, "");
     static_assert(std::is_standard_layout_v<year_month_weekday_last>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock.req/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
index 332d8163cb6..165bec2e117 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/consistency.pass.cpp
@@ -22,7 +22,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::file_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<C::time_point::clock, C>::value), "");
     static_assert(!C::is_steady, "");
     test(std::chrono::file_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
index 75652f3ecd0..61d92381fc8 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/file_time.pass.cpp
@@ -21,8 +21,10 @@ void test() {
   ASSERT_SAME_TYPE(std::chrono::file_time<Dur>, std::chrono::time_point<std::chrono::file_clock, Dur>);
 }
 
-int main() {
+int main(int, char**) {
   test<std::chrono::nanoseconds>();
   test<std::chrono::minutes>();
   test<std::chrono::hours>();
+
+  return 0;
 }
\ No newline at end of file
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
index 3b51b91b501..79cdf06120c 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/now.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::file_clock C;
     ASSERT_NOEXCEPT(C::now());
@@ -31,4 +31,6 @@ int main()
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
index c36649a5d41..821072e6df6 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.file/rep_signed.pass.cpp
@@ -20,9 +20,11 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::is_signed<std::chrono::file_clock::rep>::value, "");
     assert(std::chrono::file_clock::duration::min() <
            std::chrono::file_clock::duration::zero());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
index 6f06e718e25..1650d3b6b5f 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/consistency.pass.cpp
@@ -27,7 +27,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -35,4 +35,6 @@ int main()
     static_assert((std::is_same<C::duration, C::time_point::duration>::value), "");
     static_assert(C::is_steady || !C::is_steady, "");
     test(std::chrono::high_resolution_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
index c1d879c6f3b..ddf3ced87da 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.hires/now.pass.cpp
@@ -15,11 +15,13 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::high_resolution_clock C;
     C::time_point t1 = C::now();
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
index 1577bc18008..0797f2cb5bc 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/consistency.pass.cpp
@@ -29,7 +29,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -37,4 +37,6 @@ int main()
     static_assert((std::is_same<C::duration, C::time_point::duration>::value), "");
     static_assert(C::is_steady, "");
     test(std::chrono::steady_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
index 248f1523f87..7d268fd67de 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.steady/now.pass.cpp
@@ -17,10 +17,12 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::steady_clock C;
     C::time_point t1 = C::now();
     C::time_point t2 = C::now();
     assert(t2 >= t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
index b15a8e2124d..b92652134ad 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/consistency.pass.cpp
@@ -27,7 +27,7 @@
 template <class T>
 void test(const T &) {}
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     static_assert((std::is_same<C::rep, C::duration::rep>::value), "");
@@ -36,4 +36,6 @@ int main()
     static_assert((std::is_same<C::time_point::clock, C>::value), "");
     static_assert((C::is_steady || !C::is_steady), "");
     test(std::chrono::system_clock::is_steady);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
index e6acef241c6..54252718d4a 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/from_time_t.pass.cpp
@@ -15,9 +15,11 @@
 #include <chrono>
 #include <ctime>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     C::time_point t1 = C::from_time_t(C::to_time_t(C::now()));
     ((void)t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
index 398cdb9d760..5802166c876 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/local_time.types.pass.cpp
@@ -26,7 +26,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using local_t = std::chrono::local_t;
     using year    = std::chrono::year;
@@ -61,4 +61,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(s0.time_since_epoch()), seconds);
     assert( s0.time_since_epoch().count() == 0);
     assert( s1.time_since_epoch().count() == 946684800L);
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
index 00a163685f6..9d74541f989 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/now.pass.cpp
@@ -15,11 +15,13 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     C::time_point t1 = C::now();
     assert(t1.time_since_epoch().count() != 0);
     assert(C::time_point::min() < t1);
     assert(C::time_point::max() > t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
index cae8375d873..967af52e11d 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/rep_signed.pass.cpp
@@ -15,8 +15,10 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::system_clock::duration::min() <
            std::chrono::system_clock::duration::zero());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
index 516f54914fd..174fbe94144 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/sys.time.types.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using system_clock = std::chrono::system_clock;
     using year         = std::chrono::year;
@@ -60,4 +60,6 @@ int main()
     ASSERT_SAME_TYPE(decltype(s0.time_since_epoch()), seconds);
     assert( s0.time_since_epoch().count() == 0);
     assert( s1.time_since_epoch().count() == 946684800L);
+
+    return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
index 0819a7b547f..86b37bb6bd1 100644
--- a/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.clock/time.clock.system/to_time_t.pass.cpp
@@ -15,9 +15,11 @@
 #include <chrono>
 #include <ctime>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock C;
     std::time_t t1 = C::to_time_t(C::now());
     ((void)t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp b/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
index 92c015eef32..08870488c16 100644
--- a/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/default_ratio.pass.cpp
@@ -18,8 +18,10 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::chrono::duration<int, std::ratio<1> >,
                    std::chrono::duration<int> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp b/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
index 94e239c1f7c..02029c02bbe 100644
--- a/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/duration.fail.cpp
@@ -15,8 +15,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<std::chrono::milliseconds> D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp b/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
index 6e78f776561..737576205cf 100644
--- a/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/positive_num.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<int, std::ratio<5, -1> > D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp b/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
index 21873788a36..20298b772cb 100644
--- a/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/ratio.fail.cpp
@@ -22,8 +22,10 @@ public:
     static const int den = D;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<int, Ratio<1> > D;
     D d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
index 6331dc95a9a..8d807c7a9b3 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.fail.cpp
@@ -20,7 +20,9 @@
 
 typedef std::chrono::duration<unsigned> unsigned_secs;
 
-int main()
+int main(int, char**)
 {
     std::chrono::abs(unsigned_secs(0));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
index 5cb52ba7623..06f9a7c7f03 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.alg/abs.pass.cpp
@@ -30,7 +30,7 @@ test(const Duration& f, const Duration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::milliseconds( 7290000));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::abs(std::chrono::hours(3));
     static_assert(h2.count() == 3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
index 9d6566a082c..d0e47b7fa8d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
index 78beffe2617..084819af3ce 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_++int.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h1(3);
@@ -38,4 +38,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
index 0b8f49fc38f..a9d136f792a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::chrono::minutes m(3);
@@ -42,4 +42,6 @@ int main()
     static_assert( (std::is_same< decltype(zero+one), D1>::value), "");
     static_assert( (std::is_same< decltype(+one),     D1>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
index 0e907b573b2..4247f2d5689 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_+=.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s(3);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
index c9f1278a376..cfdb7075b37 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--.pass.cpp
@@ -25,7 +25,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
index 5abecee1648..4afb86e0caf 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_--int.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::hours h1(3);
@@ -39,4 +39,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
index f7ab6d2e299..fe065ff5f99 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     const std::chrono::minutes m(3);
@@ -43,4 +43,6 @@ int main()
     static_assert( (std::is_same< decltype(-one),     D1>::value), "");
     static_assert( (std::is_same< decltype(+one),     D1>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
index 1752d5257b8..b457619e154 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_-=.pass.cpp
@@ -28,7 +28,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s(3);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
index 4f79398f73b..753ea5a8bc1 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_divide=.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
index 89b550d015c..649f4aa1a4c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=duration.pass.cpp
@@ -27,7 +27,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::microseconds us1(11);
@@ -41,4 +41,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
index 8ef16c7ff7c..0eb73ee674f 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_mod=rep.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::microseconds us(11);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
index b4b76fb6f50..51c20c50764 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.arithmetic/op_times=.pass.cpp
@@ -26,7 +26,7 @@ constexpr bool test_constexpr()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(3);
@@ -37,4 +37,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(test_constexpr(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
index e557bc21fb5..a9711f448c8 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::ceil<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
index b509182c41e..a6e1982d044 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/ceil.pass.cpp
@@ -32,7 +32,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 3));
@@ -47,4 +47,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::ceil<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
index 5187d3d0e7c..4151756764a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/duration_cast.pass.cpp
@@ -32,7 +32,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
     test(std::chrono::milliseconds(7265000), std::chrono::hours(2));
     test(std::chrono::milliseconds(7265000), std::chrono::minutes(121));
@@ -50,4 +50,6 @@ int main()
     static_assert(h.count() == 2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
index 62dd5a51d60..c119a800cfa 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::floor<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
index 29142bdcf3e..6783b1f67ed 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/floor.pass.cpp
@@ -31,7 +31,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::floor<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -3, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
index aadfbfdc47e..93366b83618 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::round<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
index b0789b7917d..ebd2e3194a4 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/round.pass.cpp
@@ -31,7 +31,7 @@ test(const FromDuration& f, const ToDuration& d)
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -46,4 +46,6 @@ int main()
     constexpr std::chrono::hours h2 = std::chrono::round<std::chrono::hours>(std::chrono::milliseconds(-9000000));
     static_assert(h2.count() == -2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
index a46aa526bda..0f52c36d86c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cast/toduration.fail.cpp
@@ -18,7 +18,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration_cast<int>(std::chrono::milliseconds(3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
index 912d22fdf0e..c27b528017e 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_equal.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -113,4 +113,6 @@ int main()
     static_assert(!(s1 != s2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
index 9eea6ceb3bd..de476357650 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.comparisons/op_less.pass.cpp
@@ -35,7 +35,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -151,4 +151,6 @@ int main()
     static_assert( (s1 >= s2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
index 0f6fb8d3590..4c0af92b23d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_exact.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::milliseconds ms(1);
@@ -34,4 +34,6 @@ int main()
     static_assert(us.count() == 1000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
index b35c01c40ec..4311c1bde38 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_float_to_int.fail.cpp
@@ -17,8 +17,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<double> d;
     std::chrono::duration<int> i = d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
index b66b2f3c601..fb0b488f7d8 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.fail.cpp
@@ -17,8 +17,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::microseconds us(1);
     std::chrono::milliseconds ms = us;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
index 5624327badc..f72c69c7ef1 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_inexact.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<double, std::micro> us(1);
@@ -34,4 +34,6 @@ int main()
     static_assert(ms.count() == 1./1000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
index a63471bc37d..fb127226a6c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_int_to_float.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<int> i(3);
@@ -34,4 +34,6 @@ int main()
     static_assert(d.count() == 3000, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
index 68484d1fb51..5b963f2b1f4 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/convert_overflow.pass.cpp
@@ -26,11 +26,13 @@ void f(std::chrono::seconds)
     called = true;
 }
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::duration<int, std::exa> r(1);
     f(r);
     assert(called);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
index 9edcd46f902..c598afa3651 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/default.pass.cpp
@@ -32,7 +32,9 @@ test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
index f89263bf9b0..d1a808ba154 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep.pass.cpp
@@ -31,10 +31,12 @@ test(R r)
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >(5);
     test<std::chrono::duration<int, std::ratio<3, 2> > >(5);
     test<std::chrono::duration<Rep, std::ratio<3, 2> > >(Rep(3));
     test<std::chrono::duration<double, std::ratio<2, 3> > >(5.5);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
index fc6f5700a6a..f1e60f5e54d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep01.fail.cpp
@@ -19,7 +19,9 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<int> d = 1;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
index bdbe7211b81..4a09325065c 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.fail.cpp
@@ -19,7 +19,9 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
index 3ecb76135e1..1719b1302ba 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep02.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<double> d(5);
     assert(d.count() == 5);
@@ -28,4 +28,6 @@ int main()
     constexpr std::chrono::duration<double> d2(5);
     static_assert(d2.count() == 5, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
index 831370994ee..6b4d0020379 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.cons/rep03.fail.cpp
@@ -17,7 +17,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<int> d(1.);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
index 13ad165b7bf..0d924f8f70b 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals.pass.cpp
@@ -15,7 +15,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals::chrono_literals;
 
@@ -57,4 +57,6 @@ int main()
     auto ns2 = 645.ns;
     assert ( ns == ns2 );
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
index 025100c5928..97e29e87682 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.fail.cpp
@@ -11,8 +11,10 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::chrono::hours h  = 4h;  // should fail w/conversion operator not found
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
index 9ca29086777..2e5b7bbb87b 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals1.pass.cpp
@@ -11,7 +11,7 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::chrono;
 
@@ -67,4 +67,6 @@ int main()
     assert(November  == month(11));
     assert(December  == month(12));
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
index 5c38db52713..dbc91559031 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.fail.cpp
@@ -11,9 +11,11 @@
 #include <chrono>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using std::chrono::hours;
 
     hours foo  =  4h;  // should fail w/conversion operator not found
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
index 40709103254..d0b8b33e493 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.literals/literals2.pass.cpp
@@ -13,7 +13,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     using namespace std::literals;
 
@@ -46,4 +46,6 @@ int main()
     assert ( ns == std::chrono::nanoseconds(645));
     auto ns2 = 645.ns;
     assert ( ns == ns2 );
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
index 30aa62cd9d1..ad381f00565 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_+.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -71,4 +71,6 @@ int main()
     static_assert(r.count() == 75, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
index cb0a53fdf54..86ced3fbcbd 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_-.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::seconds s1(3);
@@ -72,4 +72,6 @@ int main()
     static_assert(r.count() == -15, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
index 40f521bae01..e4190fe3385 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_duration.pass.cpp
@@ -21,7 +21,7 @@
 #include "test_macros.h"
 #include "truncate_fp.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns1(15);
@@ -65,4 +65,6 @@ int main()
     static_assert(s1 / s2 == 20./3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
index 41c55fccaeb..327ff563567 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(Rep(15));
     d = d / 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
index 8718ad75730..94da11302bf 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_divide_rep.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -34,4 +34,6 @@ int main()
     static_assert(ns2.count() == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
index 7a2063ca54e..e7007c1fe35 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_duration.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns1(15);
@@ -60,4 +60,6 @@ int main()
     static_assert(r.count() == 24, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
index 3ee0578f805..f2a5885aba6 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.fail.cpp
@@ -18,8 +18,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d(Rep(15));
     d = d % 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
index 6d7e285d9b8..754b9800a7d 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_mod_rep.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(15);
@@ -34,4 +34,6 @@ int main()
     static_assert(ns2.count() == 3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
index 19e33366f71..c3e49963808 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     std::chrono::nanoseconds ns(3);
@@ -43,4 +43,6 @@ int main()
     static_assert(ns3.count() == 18, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
index 6ad3c7928a9..44a77cea18a 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep1.fail.cpp
@@ -22,8 +22,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d;
     d = d * 5;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
index 5cc717c5c04..9ce82582cf3 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.nonmember/op_times_rep2.fail.cpp
@@ -22,8 +22,10 @@
 
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     std::chrono::duration<Rep> d;
     d = 5 * d;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.observer/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
index c6f3f1e6547..58de66a0158 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/max.pass.cpp
@@ -40,8 +40,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
index b16e608dcc7..9b0113b2980 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/min.pass.cpp
@@ -40,8 +40,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
index f3065c30542..34a05b5f071 100644
--- a/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/time.duration.special/zero.pass.cpp
@@ -39,8 +39,10 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int> >();
     test<std::chrono::duration<Rep> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.duration/types.pass.cpp b/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
index 9e5abbc20a7..250e532859e 100644
--- a/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.duration/types.pass.cpp
@@ -18,9 +18,11 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::duration<long, std::ratio<3, 2> > D;
     static_assert((std::is_same<D::rep, long>::value), "");
     static_assert((std::is_same<D::period, std::ratio<3, 2> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
index e645e2970c6..8a58413a0aa 100644
--- a/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/default_duration.pass.cpp
@@ -18,8 +18,10 @@
 #include <chrono>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     static_assert((std::is_same<std::chrono::system_clock::duration,
                    std::chrono::time_point<std::chrono::system_clock>::duration>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/duration.fail.cpp b/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
index a4881acc931..6461eb3d96f 100644
--- a/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/duration.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::time_point<std::chrono::system_clock, int> T;
     T t;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
index 999071b72c6..002fffc3882 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_+=.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool constexpr_test()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::chrono::system_clock Clock;
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(constexpr_test(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
index 3d62cdedaac..2365d539ca7 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.arithmetic/op_-=.pass.cpp
@@ -29,7 +29,7 @@ constexpr bool constexpr_test()
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::chrono::system_clock Clock;
@@ -42,4 +42,6 @@ int main()
 #if TEST_STD_VER > 14
     static_assert(constexpr_test(), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
index 4a90ec870cf..fb82fdffe4d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::ceil<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
index efd2a3e592b..8dfd1bdaa38 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/ceil.pass.cpp
@@ -49,7 +49,7 @@ void test_constexpr ()
 }
 
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 3));
@@ -65,4 +65,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
index c5dfba6c4f1..12b1dec9fd5 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::floor<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
index db2391d2518..d50fff4a1c8 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/floor.pass.cpp
@@ -48,7 +48,7 @@ void test_constexpr ()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -64,4 +64,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
index 6c6f9c5bf5c..a5436c68404 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.fail.cpp
@@ -19,7 +19,9 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     std::chrono::round<int>(std::chrono::system_clock::now());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
index e68e233969d..d8bb1b505b1 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/round.pass.cpp
@@ -48,7 +48,7 @@ void test_constexpr ()
     }
 }
 
-int main()
+int main(int, char**)
 {
 //  7290000ms is 2 hours, 1 minute, and 30 seconds
     test(std::chrono::milliseconds( 7290000), std::chrono::hours( 2));
@@ -64,4 +64,6 @@ int main()
 
     test_constexpr<std::chrono::milliseconds, 9000000, std::chrono::seconds, 9000> ();
     test_constexpr<std::chrono::milliseconds,-9000000, std::chrono::seconds,-9000> ();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
index 5779ef9208a..90e6ccef666 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/time_point_cast.pass.cpp
@@ -54,7 +54,7 @@ void test_constexpr ()
 
 #endif
 
-int main()
+int main(int, char**)
 {
     test(std::chrono::milliseconds(7265000), std::chrono::hours(2));
     test(std::chrono::milliseconds(7265000), std::chrono::minutes(121));
@@ -78,4 +78,6 @@ int main()
     test_constexpr<std::chrono::duration<int, std::ratio<2, 3>>, 9, T1, 10> ();
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
index 9e1f903b93f..c16492f730a 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cast/toduration.fail.cpp
@@ -18,10 +18,12 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::time_point<Clock, std::chrono::milliseconds> FromTimePoint;
     typedef std::chrono::time_point<Clock, std::chrono::minutes> ToTimePoint;
     std::chrono::time_point_cast<ToTimePoint>(FromTimePoint(std::chrono::milliseconds(3)));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
index e2b3508e000..2b5795026b3 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.fail.cpp
@@ -24,7 +24,7 @@
 
 #include "../../clock.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock1;
     typedef Clock                     Clock2;
@@ -36,4 +36,6 @@ int main()
     T1 t1(Duration1(3));
     T2 t2(Duration2(3000));
     t1 == t2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
index cc2ef333763..f110ec5d406 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_equal.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -82,4 +82,6 @@ int main()
     static_assert( (t1 != t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
index 04f7639d605..3d158ea890f 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.fail.cpp
@@ -32,7 +32,7 @@
 
 #include "../../clock.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock1;
     typedef Clock                     Clock2;
@@ -44,4 +44,6 @@ int main()
     T1 t1(Duration1(3));
     T2 t2(Duration2(3000));
     t1 < t2;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
index 57d24d08d02..3b4aa6abecf 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.comparisons/op_less.pass.cpp
@@ -31,7 +31,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -106,4 +106,6 @@ int main()
     static_assert(!(t1 >= t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
index a68d4b0f304..2e601179a7d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.fail.cpp
@@ -17,7 +17,7 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -26,4 +26,6 @@ int main()
     std::chrono::time_point<Clock, Duration2> t2(Duration2(3));
     std::chrono::time_point<Clock, Duration1> t1 = t2;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
index 91bcebb1a91..f9b35c95738 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/convert.pass.cpp
@@ -18,7 +18,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::microseconds Duration1;
@@ -35,4 +35,6 @@ int main()
     static_assert(t1.time_since_epoch() == Duration1(3000), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
index 2deb8ae298c..b40113999a5 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/default.pass.cpp
@@ -18,7 +18,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::duration<Rep, std::milli> Duration;
@@ -32,4 +32,6 @@ int main()
     static_assert(t.time_since_epoch() == Duration::zero(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
index 4a42eef3057..b28116236d0 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.fail.cpp
@@ -16,9 +16,11 @@
 
 #include <chrono>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
     std::chrono::time_point<Clock, Duration> t = Duration(3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
index 0830eea9119..078c6641e76 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.cons/duration.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -39,4 +39,6 @@ int main()
     static_assert(t.time_since_epoch() == Duration(3000), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
index df6c691572e..7d78f7f4329 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_+.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -44,4 +44,6 @@ int main()
     static_assert(t3.time_since_epoch() == Duration2(3006), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
index 876d42d560d..6fe8769695b 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-duration.pass.cpp
@@ -30,7 +30,7 @@ void test2739()  // LWG2739
     assert(t1 < t0);
 }
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -49,4 +49,6 @@ int main()
 #endif
     test2739<int32_t>();
     test2739<uint32_t>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
index 851869d4d0d..22e4520f360 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.nonmember/op_-time_point.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration1;
@@ -36,4 +36,6 @@ int main()
     static_assert((t1 - t2) == Duration2(2995), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.observer/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
index c8f2d41be97..e7826b1a610 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.special/max.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -27,4 +27,6 @@ int main()
     ASSERT_NOEXCEPT(       TP::max());
 #endif
     assert(TP::max() == TP(Duration::max()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp b/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
index 1cac230624f..fae3339b03d 100644
--- a/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.point/time.point.special/min.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::system_clock Clock;
     typedef std::chrono::milliseconds Duration;
@@ -27,4 +27,6 @@ int main()
     ASSERT_NOEXCEPT(       TP::max());
 #endif
     assert(TP::min() == TP(Duration::min()));
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
index f44a7964f02..8d244c77346 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/max.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::max() ==
            std::numeric_limits<int>::max());
@@ -42,4 +42,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<double>::max());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::max());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
index c64746d9fc7..4ff03c62286 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/min.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::min() ==
            std::numeric_limits<int>::lowest());
@@ -42,4 +42,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<double>::min());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::min());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
index 6eec47ce3b0..d9de07b414e 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.duration_values/zero.pass.cpp
@@ -16,7 +16,7 @@
 #include "test_macros.h"
 #include "../../rep.h"
 
-int main()
+int main(int, char**)
 {
     assert(std::chrono::duration_values<int>::zero() == 0);
     assert(std::chrono::duration_values<Rep>::zero() == 0);
@@ -31,4 +31,6 @@ int main()
     ASSERT_NOEXCEPT(std::chrono::duration_values<int>::zero());
     ASSERT_NOEXCEPT(std::chrono::duration_values<Rep>::zero());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
index cf588f5c0af..9db3d96d26d 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.is_fp/treat_as_floating_point.pass.cpp
@@ -29,7 +29,7 @@ test()
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     test<int>();
     test<unsigned>();
@@ -39,4 +39,6 @@ int main()
     test<double>();
     test<long double>();
     test<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
index 39afe6a5f53..3dde5404727 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/duration.pass.cpp
@@ -24,7 +24,7 @@ test()
     static_assert((std::is_same<Dc, De>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int, std::ratio<1, 100> >,
          std::chrono::duration<long, std::ratio<1, 1000> >,
@@ -38,4 +38,6 @@ int main()
     test<std::chrono::duration<double, std::ratio<21, 1> >,
          std::chrono::duration<short, std::ratio<15, 1> >,
          std::chrono::duration<double, std::ratio<3, 1> > >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
index bf880fcd2b7..d73bb8ae6fd 100644
--- a/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
+++ b/libcxx/test/std/utilities/time/time.traits/time.traits.specializations/time_point.pass.cpp
@@ -28,7 +28,7 @@ test()
     static_assert((std::is_same<Tc, Te>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::chrono::duration<int, std::ratio<1, 100> >,
          std::chrono::duration<long, std::ratio<1, 1000> >,
@@ -42,4 +42,6 @@ int main()
     test<std::chrono::duration<double, std::ratio<21, 1> >,
          std::chrono::duration<short, std::ratio<15, 1> >,
          std::chrono::duration<double, std::ratio<3, 1> > >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/weeks.pass.cpp b/libcxx/test/std/utilities/time/weeks.pass.cpp
index 2231c69550c..5a0cf3417f5 100644
--- a/libcxx/test/std/utilities/time/weeks.pass.cpp
+++ b/libcxx/test/std/utilities/time/weeks.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::weeks D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 22, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<7>, std::chrono::days::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/time/years.pass.cpp b/libcxx/test/std/utilities/time/years.pass.cpp
index c2229caee63..5016369268a 100644
--- a/libcxx/test/std/utilities/time/years.pass.cpp
+++ b/libcxx/test/std/utilities/time/years.pass.cpp
@@ -15,7 +15,7 @@
 #include <type_traits>
 #include <limits>
 
-int main()
+int main(int, char**)
 {
     typedef std::chrono::years D;
     typedef D::rep Rep;
@@ -24,4 +24,6 @@ int main()
     static_assert(std::is_integral<Rep>::value, "");
     static_assert(std::numeric_limits<Rep>::digits >= 17, "");
     static_assert(std::is_same_v<Period, std::ratio_multiply<std::ratio<146097, 400>, std::chrono::days::period>>, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
index d216c19fc54..5d0409a7ca3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp
@@ -39,7 +39,7 @@ constexpr bool test_ignore_constexpr()
     return true;
 }
 
-int main() {
+int main(int, char**) {
     {
         constexpr auto& ignore_v = std::ignore;
         ((void)ignore_v);
@@ -50,4 +50,6 @@ int main() {
     {
         LIBCPP_STATIC_ASSERT(std::is_trivial<decltype(std::ignore)>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
index 326d7bb589e..d57e7ad1825 100644
--- a/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.general/tuple.smartptr.pass.cpp
@@ -15,7 +15,7 @@
 #include <tuple>
 #include <memory>
 
-int main () {
+int main(int, char**) {
     {
     std::tuple<std::unique_ptr<char>> up;
     std::tuple<std::shared_ptr<char>> sp;
@@ -29,4 +29,6 @@ int main () {
     // Smart pointers of type 'T[N]' are not tested here since they are not
     // supported by the standard nor by libc++'s implementation.
     // See https://reviews.llvm.org/D21320 for more information.
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
index b9e6e111ca1..27f3d59349b 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/TupleFunction.pass.cpp
@@ -25,11 +25,13 @@ struct X
     void operator()() {}
 };
 
-int main()
+int main(int, char**)
 {
     X x;
     std::function<void()> f(x);
+
+  return 0;
 }
 #else
-int main () {}
+int main(int, char**) { return 0; }
 #endif
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
index 2daef09fb08..52e94cc0b61 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply.pass.cpp
@@ -265,9 +265,11 @@ void test_return_type()
     test<13, int const volatile *>();
 }
 
-int main() {
+int main(int, char**) {
     test_constexpr_evaluation();
     test_call_quals_and_arg_types();
     test_return_type();
     test_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
index 978c923ef0c..851a535eb49 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_extended_types.pass.cpp
@@ -360,7 +360,7 @@ void test_ext_int_2()
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         test_ext_int_0<
@@ -422,4 +422,6 @@ int main()
           , std::tuple<A_base_2, int, int>, std::tuple<A_base_2 const, int, int>
           >();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
index 138f074b243..004a5d46435 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/apply_large_arity.pass.cpp
@@ -129,7 +129,7 @@ void test_one()
     }
 }
 
-int main()
+int main(int, char**)
 {
     // Instantiate with 1-5 arguments.
     test_all<1>();
@@ -140,4 +140,6 @@ int main()
 
     // Stress test with 256
     test_one<256>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
index 6afd8882512..53574ee1d80 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.apply/make_from_tuple.pass.cpp
@@ -205,9 +205,11 @@ void test_noexcept() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     test_constexpr_construction();
     test_perfect_forwarding();
     test_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
index bf4a8cc0dbb..9353add370f 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/const_pair.pass.cpp
@@ -19,7 +19,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, char> T0;
@@ -30,4 +30,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1) == short('a'));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
index e21118a2f55..8b9447c9900 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_copy.pass.cpp
@@ -32,7 +32,7 @@ struct D
     explicit D(int i = 0) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -85,4 +85,6 @@ int main()
         assert(std::get<0>(t) == 43);
         assert(&std::get<0>(t) == &x);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
index 95b1e2769de..71855a309c5 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/convert_move.pass.cpp
@@ -43,7 +43,7 @@ struct E {
   }
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -106,4 +106,6 @@ int main()
         assert(std::get<0>(t) == 43);
         assert(&std::get<0>(t) == &x);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
index 167d442b726..c3fa6495ff7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.fail.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<MoveOnly> T;
@@ -27,4 +27,6 @@ int main()
         T t;
         t = t0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
index 5162c40533d..f6ff1041e5c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/copy.pass.cpp
@@ -35,7 +35,7 @@ struct MoveAssignable {
   MoveAssignable& operator=(MoveAssignable&&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -100,4 +100,6 @@ int main()
         using T = std::tuple<int, MoveAssignable>;
         static_assert(!std::is_copy_assignable<T>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
index 4545cf4df2b..575c3b1dfad 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move.pass.cpp
@@ -48,7 +48,7 @@ int CountAssign::copied = 0;
 int CountAssign::moved = 0;
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -122,4 +122,6 @@ int main()
         assert(CountAssign::copied == 1);
         assert(CountAssign::moved == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
index 2dec9fffae5..9681a238a9d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/move_pair.pass.cpp
@@ -35,7 +35,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, std::unique_ptr<D>> T0;
@@ -46,4 +46,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
index 5e31090c9d5..5796e8dbe08 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.assign/tuple_array_template_depth.pass.cpp
@@ -25,9 +25,11 @@
 typedef std::array<char, 1256> array_t;
 typedef std::tuple<array_t> tuple_t;
 
-int main()
+int main(int, char**)
 {
     array_t arr;
     tuple_t tup;
     tup = arr;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
index b6e444c659f..973aa93df3c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR20855_tuple_ref_binding_diagnostics.pass.cpp
@@ -131,7 +131,9 @@ void allocator_tests() {
 }
 
 
-int main() {
+int main(int, char**) {
   compile_tests();
   allocator_tests();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
index 79064fb09c4..1e1b0846cc2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR22806_constrain_tuple_like_ctor.pass.cpp
@@ -78,7 +78,7 @@ struct ConvertibleFromInt {
   ConvertibleFromInt(int) : state(FromInt) {}
 };
 
-int main()
+int main(int, char**)
 {
     // Test for the creation of dangling references when a tuple is used to
     // store a reference to another tuple as its only element.
@@ -174,4 +174,6 @@ int main()
         std::tuple<VT> t2 = {t1};
         assert(std::get<0>(t2).state == VT::FromInt);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
index 8992f7b8205..919d88e46a3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR23256_constrain_UTypes_ctor.pass.cpp
@@ -57,7 +57,7 @@ struct ExplicitUnconstrainedCtor {
 
 };
 
-int main() {
+int main(int, char**) {
     typedef UnconstrainedCtor A;
     typedef ExplicitUnconstrainedCtor ExplicitA;
     {
@@ -94,4 +94,6 @@ int main() {
         std::tuple<ExplicitA&&> t2(std::forward_as_tuple(ExplicitA{}));
         ((void)t2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
index 9f8658aa642..1493f4f8160 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR27684_contains_ref_to_incomplete_type.pass.cpp
@@ -29,7 +29,7 @@ extern IncompleteType inc2;
 IncompleteType const& cinc1 = inc1;
 IncompleteType const& cinc2 = inc2;
 
-int main() {
+int main(int, char**) {
     using IT = IncompleteType;
     { // try calling tuple(Tp const&...)
         using Tup = std::tuple<const IT&, const IT&>;
@@ -43,6 +43,8 @@ int main() {
         assert(&std::get<0>(t) == &inc1);
         assert(&std::get<1>(t) == &inc2);
     }
+
+  return 0;
 }
 
 struct IncompleteType {};
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
index b0dd392f171..6c44f7027ee 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/PR31384.pass.cpp
@@ -44,7 +44,7 @@ struct ExplicitDerived : std::tuple<T> {
   explicit operator std::tuple<U>() && { ++count; return {}; }
 };
 
-int main() {
+int main(int, char**) {
   {
     std::tuple<Explicit> foo = Derived<int>{42}; ((void)foo);
     assert(count == 1);
@@ -84,4 +84,6 @@ int main() {
   }
   count = 0;
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
index 3a0e0f888e9..3b9d0beead9 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.fail.cpp
@@ -42,9 +42,11 @@ public:
     bool operator< (const MoveOnly& x) const {return data_ <  x.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<MoveOnly> t = 1;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
index f43e6d8bced..916255c967a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/UTypes.pass.cpp
@@ -102,7 +102,7 @@ void test_default_constructible_extension_sfinae()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<MoveOnly> t(MoveOnly(0));
@@ -156,4 +156,6 @@ int main()
     // Check that SFINAE is properly applied with the default reduced arity
     // constructor extensions.
     test_default_constructible_extension_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
index e4ed4769002..c5f52a92846 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc.pass.cpp
@@ -39,7 +39,7 @@ struct NonDefaultConstructible {
 
 struct DerivedFromAllocArgT : std::allocator_arg_t {};
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t(std::allocator_arg, A1<int>());
@@ -105,4 +105,6 @@ int main()
         std::tuple<T, T> t2(42, 42);
         (void)t2;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
index 99155823b3a..57e2f1b4188 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_UTypes.pass.cpp
@@ -77,7 +77,7 @@ struct Explicit {
   explicit Explicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<Explicit> t{std::allocator_arg, std::allocator<void>{}, 42};
@@ -148,4 +148,6 @@ int main()
     // ensure that the "reduced-arity-initialization" extension is not offered
     // for these constructors.
     test_uses_allocator_sfinae_evaluation();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
index 1759ba4f3c4..76f99e1978d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.fail.cpp
@@ -35,8 +35,10 @@ std::tuple<ExplicitCopy> non_const_explicity_copy_test() {
     return {std::allocator_arg, std::allocator<void>{}, e};
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
-int main()
+int main(int, char**)
 {
     const_explicit_copy_test();
     non_const_explicity_copy_test();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
index 10647a49d14..3b5b27f7b15 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_Types.pass.cpp
@@ -40,7 +40,7 @@ std::tuple<ImplicitCopy> testImplicitCopy2() {
     return {std::allocator_arg, std::allocator<void>{}, i};
 }
 
-int main()
+int main(int, char**)
 {
     {
         // check that the literal '0' can implicitly initialize a stored pointer.
@@ -94,4 +94,6 @@ int main()
         assert(!alloc_last::allocator_constructed);
         assert(std::get<2>(t) == alloc_last(3));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
index baafee879f9..a7cffa72db6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_const_pair.pass.cpp
@@ -23,7 +23,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, int> T0;
@@ -55,4 +55,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1) == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
index 8d0482859a0..ca9518d6b2b 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.fail.cpp
@@ -36,7 +36,9 @@ std::tuple<ExplicitCopy> non_const_explicit_copy_test() {
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
 
-int main()
+int main(int, char**)
 {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
index bcece609830..083e15797f6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_copy.pass.cpp
@@ -33,7 +33,7 @@ struct Implicit {
   Implicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -86,4 +86,6 @@ int main()
         std::tuple<Implicit> t2 = {std::allocator_arg, std::allocator<void>{}, t1};
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
index ed485c90107..7a2a5ffff5d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.fail.cpp
@@ -29,7 +29,9 @@ std::tuple<ExplicitCopy> explicit_move_test() {
     // expected-error@-1 {{chosen constructor is explicit in copy-initialization}}
 }
 
-int main()
+int main(int, char**)
 {
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
index e86ec8aea92..1f33ef2fc6e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_convert_move.pass.cpp
@@ -49,7 +49,7 @@ struct Implicit {
   Implicit(int x) : value(x) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T0;
@@ -100,4 +100,6 @@ int main()
         std::tuple<Implicit> t2 = {std::allocator_arg, std::allocator<void>{}, std::move(t1)};
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
index 19829a967bb..1db842b8d91 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_copy.pass.cpp
@@ -22,7 +22,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -77,4 +77,6 @@ int main()
         assert(std::get<2>(t) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
index c77484de54b..fc25a4fc6a4 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move.pass.cpp
@@ -23,7 +23,7 @@
 #include "../alloc_first.h"
 #include "../alloc_last.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -76,4 +76,6 @@ int main()
         assert(std::get<2>(t) == 3);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
index 3da2d8a466d..e45702d88b7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/alloc_move_pair.pass.cpp
@@ -39,7 +39,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, std::unique_ptr<D>> T0;
@@ -51,4 +51,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
index 2a405c1a4af..bb7c5573505 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.fail.cpp
@@ -42,6 +42,8 @@ std::tuple<ExplicitCopy> const_explicit_copy_no_brace() {
     // expected-error@-1 {{no viable conversion}}
 }
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
index 955a83a6e88..d4c29c93c37 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types.pass.cpp
@@ -76,7 +76,7 @@ std::tuple<ImplicitCopy> testImplicitCopy3() {
     return i;
 }
 
-int main()
+int main(int, char**)
 {
     {
         // check that the literal '0' can implicitly initialize a stored pointer.
@@ -159,4 +159,6 @@ int main()
         assert(std::get<3>(t) == 0.0);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
index 35e82277f8d..8804c27b8a2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_Types2.fail.cpp
@@ -18,9 +18,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<int, char*, std::string, double&> t(2, nullptr, "text");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
index 0fd29b22fd7..bbe51e39254 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/const_pair.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, char> T0;
@@ -42,4 +42,6 @@ int main()
         static_assert(std::get<1>(t1) == short('a'), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
index 98d002b8042..41f73328ab7 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_copy.pass.cpp
@@ -64,7 +64,7 @@ struct C
 
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -136,4 +136,6 @@ int main()
         std::tuple<Implicit> t2 = t1;
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
index 79332841eb8..071f13cf913 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/convert_move.pass.cpp
@@ -44,7 +44,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<long> T0;
@@ -100,4 +100,6 @@ int main()
         std::tuple<Implicit> t2 = std::move(t1);
         assert(std::get<0>(t2).value == 42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
index f82dc6b1ff2..7eeb65a8fdd 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.fail.cpp
@@ -19,11 +19,13 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<MoveOnly> T;
         T t0(MoveOnly(2));
         T t = t0;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
index 7c581cb7714..01278130400 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/copy.pass.cpp
@@ -22,7 +22,7 @@
 
 struct Empty {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -66,4 +66,6 @@ int main()
         ((void)e); // Prevent unused warning
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
index 15bcde7e973..ae296f73945 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/default.pass.cpp
@@ -44,7 +44,7 @@ struct IllFormedDefault {
     int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t;
@@ -106,4 +106,6 @@ int main()
         IllFormedDefault v(0);
         std::tuple<IllFormedDefault> t(v);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
index 1d4779aae36..80b09b87180 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/dtor.pass.cpp
@@ -23,7 +23,7 @@
 #include <cassert>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
   static_assert(std::is_trivially_destructible<
       std::tuple<> >::value, "");
@@ -35,4 +35,6 @@ int main()
       std::tuple<std::string> >::value, "");
   static_assert(!std::is_trivially_destructible<
       std::tuple<int, std::string> >::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
index ea393abafe4..3ff089a0b31 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/implicit_deduction_guides.pass.cpp
@@ -149,7 +149,9 @@ void test_empty_specialization()
   }
 }
 
-int main() {
+int main(int, char**) {
   test_primary_template();
   test_empty_specialization();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
index 98a12a972f8..977dc4c3264 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move.pass.cpp
@@ -80,7 +80,7 @@ void test_sfinae() {
     }
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -121,4 +121,6 @@ int main()
         test_sfinae<move_only_ebo>();
         test_sfinae<move_only_large>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
index 3953ee150a2..635be614b9a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/move_pair.pass.cpp
@@ -34,7 +34,7 @@ struct D
     explicit D(int i) : B(i) {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<long, std::unique_ptr<D>> T0;
@@ -44,4 +44,6 @@ int main()
         assert(std::get<0>(t1) == 2);
         assert(std::get<1>(t1)->id_ == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
index 24868515643..bdbe4fc4b44 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/test_lazy_sfinae.pass.cpp
@@ -95,7 +95,9 @@ void test_const_Types_lazy_sfinae()
     assert(std::get<0>(t).value == 42);
 }
 
-int main() {
+int main(int, char**) {
     test_tuple_like_lazy_sfinae();
     test_const_Types_lazy_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
index b84dba37899..2f9447f2a7d 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.cnstr/tuple_array_template_depth.pass.cpp
@@ -28,8 +28,10 @@
 typedef std::array<char, 1256> array_t;
 typedef std::tuple<array_t> tuple_t;
 
-int main()
+int main(int, char**)
 {
     array_t arr;
     tuple_t tup(arr);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
index 5a7940da656..8dc1e48f867 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/forward_as_tuple.pass.cpp
@@ -64,7 +64,7 @@ test3(const Tuple&)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         test0(std::forward_as_tuple());
@@ -84,4 +84,6 @@ int main()
         static_assert ( test3 (std::forward_as_tuple(i, c)) == 2, "" );
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
index 3f0dae093f0..444e978b01e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/make_tuple.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -50,4 +50,6 @@ int main()
         static_assert (d1 == 3.14, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
index f703ef2c849..53ccc23b97c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tie.pass.cpp
@@ -39,7 +39,7 @@ constexpr bool test_tie_constexpr() {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         int i = 0;
@@ -60,4 +60,6 @@ int main()
         static_assert(test_tie_constexpr(), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
index 927fc2ab891..40efbd1b801 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.creation/tuple_cat.pass.cpp
@@ -23,7 +23,7 @@
 #include "test_macros.h"
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::tuple<> t = std::tuple_cat();
@@ -238,4 +238,6 @@ int main()
         );
         assert(t2 == std::make_tuple(std::make_tuple(1), std::make_tuple(2)));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
index 4c0b5a6b460..650303ff7b2 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.fail.cpp
@@ -20,7 +20,7 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<double&, std::string, int> T;
@@ -37,4 +37,6 @@ int main()
 
         std::get<1>(t) = "four";
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
index 5ca0bd8e963..a280c500ba5 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const.pass.cpp
@@ -24,7 +24,7 @@
 
 struct Empty {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T;
@@ -64,4 +64,6 @@ int main()
         assert(std::get<2>(t) == 5);
         assert(d == 2.5);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
index 373d84bad99..cf0e88246d3 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.fail.cpp
@@ -23,11 +23,13 @@ template <class T> void cref(T const&&) = delete;
 
 std::tuple<int> const tup4() { return std::make_tuple(4); }
 
-int main()
+int main(int, char**)
 {
     // LWG2485: tuple should not open a hole in the type system, get() should
     // imitate [expr.ref]'s rules for accessing data members
     {
         cref(std::get<0>(tup4()));  // expected-error {{call to deleted function 'cref'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
index 4c2654cd735..5801d5a5e65 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_const_rv.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::tuple<int> T;
@@ -76,4 +76,6 @@ int main()
     static_assert(std::get<1>(std::move(t)) == 5, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
index 3708e5cb0ca..3cbf01b25f8 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_non_const.pass.cpp
@@ -36,7 +36,7 @@ struct S {
 constexpr std::tuple<int, int> getP () { return { 3, 4 }; }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<int> T;
@@ -81,4 +81,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
index 114672b7c7a..ae968403b01 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/get_rv.pass.cpp
@@ -21,7 +21,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<std::unique_ptr<int> > T;
@@ -29,4 +29,6 @@ int main()
         std::unique_ptr<int> p = std::get<0>(std::move(t));
         assert(*p == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
index f85c8098f7d..51bf1d550cd 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.fail.cpp
@@ -31,8 +31,10 @@ void test_bad_return_type() {
     upint p = std::get<upint>(t); // expected-error{{deleted copy constructor}}
 }
 
-int main()
+int main(int, char**)
 {
     test_bad_index();
     test_bad_return_type();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
index 9df8ce381a7..7dd4e8f10ad 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.elem/tuple.by.type.pass.cpp
@@ -17,7 +17,7 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     {
@@ -90,4 +90,6 @@ int main()
     static_assert(std::get<int>(std::move(t)) == 1, "");
     static_assert(std::get<const int>(std::move(t)) == 2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
index e56f86a1cca..a97e60ca779 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.array.pass.cpp
@@ -40,7 +40,7 @@ void test()
     static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::array<int, 5>, 5, int, 0>();
     test<std::array<int, 5>, 5, int, 1>();
@@ -48,4 +48,6 @@ int main()
     test<std::array<volatile int, 4>, 4, volatile int, 3>();
     test<std::array<char *, 3>, 3, char *, 1>();
     test<std::array<char *, 3>, 3, char *, 2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
index eb1704c943b..fdfb8b8b0a8 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple.include.utility.pass.cpp
@@ -38,7 +38,7 @@ void test()
     static_assert((std::is_same<typename std::tuple_element<idx, const volatile T>::type, const volatile U>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::pair<int, int>, 2, int, 0>();
     test<std::pair<int, int>, 2, int, 1>();
@@ -46,4 +46,6 @@ int main()
     test<std::pair<int, volatile int>, 2, volatile int, 1>();
     test<std::pair<char *, int>, 2, char *, 0>();
     test<std::pair<char *, int>, 2, int,    1>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
index a1c42921ba2..24b735b7e68 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.fail.cpp
@@ -22,7 +22,7 @@
 #include <tuple>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     using T =  std::tuple<int, long, void*>;
     using E1 = typename std::tuple_element<1, T &>::type; // expected-error{{undefined template}}
@@ -30,4 +30,6 @@ int main()
     using E3 = typename std::tuple_element<4, T const>::type;
         // expected-error@__tuple:* 2 {{static_assert failed}}
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
index ecb6ea087ef..5ad2b08220e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
@@ -39,7 +39,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<int>, 0, int>();
     test<std::tuple<char, int>, 0, char>();
@@ -47,4 +47,6 @@ int main()
     test<std::tuple<int*, char, int>, 0, int*>();
     test<std::tuple<int*, char, int>, 1, char>();
     test<std::tuple<int*, char, int>, 2, int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
index aa20818393b..9b065b3b9f6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.fail.cpp
@@ -18,9 +18,11 @@
 
 #include <tuple>
 
-int main()
+int main(int, char**)
 {
     (void)std::tuple_size<std::tuple<> &>::value; // expected-error {{implicit instantiation of undefined template}}
     (void)std::tuple_size<int>::value; // expected-error {{implicit instantiation of undefined template}}
     (void)std::tuple_size<std::tuple<>*>::value; // expected-error {{implicit instantiation of undefined template}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
index 2a602b1ca26..f27c7eb470a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size.pass.cpp
@@ -32,10 +32,12 @@ void test()
                                    std::tuple_size<const volatile T> >::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<>, 0>();
     test<std::tuple<int>, 1>();
     test<std::tuple<char, int>, 2>();
     test<std::tuple<char, char*, int>, 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
index 3d092506828..83b773abf22 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.fail.cpp
@@ -39,7 +39,7 @@ public:
 template <>
 struct std::tuple_size<Dummy3> {};
 
-int main()
+int main(int, char**)
 {
   // Test that tuple_size<const T> is not incomplete when tuple_size<T>::value
   // is well-formed but not a constant expression.
@@ -59,4 +59,6 @@ int main()
     // expected-error@__tuple:* 1 {{no member named 'value'}}
     (void)std::tuple_size<const Dummy3>::value; // expected-note {{here}}
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
index 44e100c6d36..32bad3317bc 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_incomplete.pass.cpp
@@ -50,7 +50,7 @@ void test_incomplete() {
 }
 
 
-int main()
+int main(int, char**)
 {
   test_complete<std::tuple<> >();
   test_complete<std::tuple<int&> >();
@@ -63,4 +63,6 @@ int main()
   test_incomplete<int>();
   test_incomplete<std::tuple<int>&>();
   test_incomplete<Dummy2>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
index f191f9f64d7..00f7ff26972 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_structured_bindings.pass.cpp
@@ -139,11 +139,13 @@ void test_after_tuple_size_specialization() {
   assert(p == -1);
 }
 
-int main() {
+int main(int, char**) {
   test_decomp_user_type();
   test_decomp_tuple();
   test_decomp_pair();
   test_decomp_array();
   test_before_tuple_size_specialization();
   test_after_tuple_size_specialization();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
index 820cb0443f8..8bd3fbd579e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.fail.cpp
@@ -16,10 +16,12 @@
 
 #include <tuple>
 
-int main()
+int main(int, char**)
 {
     (void)std::tuple_size_v<std::tuple<> &>; // expected-note {{requested here}}
     (void)std::tuple_size_v<int>; // expected-note {{requested here}}
     (void)std::tuple_size_v<std::tuple<>*>; // expected-note {{requested here}}
     // expected-error@tuple:* 3 {{implicit instantiation of undefined template}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
index b2b3e72b9be..bd01f49497c 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_v.pass.cpp
@@ -26,7 +26,7 @@ void test()
     static_assert(std::tuple_size_v<Tuple const volatile> == std::tuple_size<Tuple>::value, "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::tuple<>, 0>();
 
@@ -39,4 +39,6 @@ int main()
 
     test<std::tuple<int, int, int>, 3>();
     test<std::array<int, 3>, 3>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
index 9c00418768f..2efbfa50e15 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.helper/tuple_size_value_sfinae.pass.cpp
@@ -27,7 +27,7 @@ template <class T> constexpr bool has_value() { return has_value<T>(0); }
 
 struct Dummy {};
 
-int main() {
+int main(int, char**) {
   // Test that the ::value member does not exist
   static_assert(has_value<std::tuple<int> const>(), "");
   static_assert(has_value<std::pair<int, long> volatile>(), "");
@@ -35,4 +35,6 @@ int main() {
   static_assert(!has_value<const int>(), "");
   static_assert(!has_value<volatile void>(), "");
   static_assert(!has_value<const volatile std::tuple<int>&>(), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
index 709f747c744..0302c839e74 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/eq.pass.cpp
@@ -22,7 +22,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T1;
@@ -154,4 +154,6 @@ int main()
         static_assert(t1 != t2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
index 9f29c6c4a1b..64ed9b4a90e 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.rel/lt.pass.cpp
@@ -34,7 +34,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T1;
@@ -208,4 +208,6 @@ int main()
         static_assert(!(t1 >= t2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
index 079977016b8..eee8f18196a 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.special/non_member_swap.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -58,4 +58,6 @@ int main()
         assert(std::get<1>(t1) == 1);
         assert(std::get<2>(t1) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
index 097f69b42ea..951a8872609 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.swap/member_swap.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "MoveOnly.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -57,4 +57,6 @@ int main()
         assert(std::get<1>(t1) == 1);
         assert(std::get<2>(t1) == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
index 5e4722874af..b04c491ede6 100644
--- a/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
+++ b/libcxx/test/std/utilities/tuple/tuple.tuple/tuple.traits/uses_allocator.pass.cpp
@@ -20,7 +20,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::tuple<> T;
@@ -42,4 +42,6 @@ int main()
         static_assert((std::is_base_of<std::true_type,
                                        std::uses_allocator<T, A>>::value), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
index daa287e3e01..710b33878d9 100644
--- a/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
index 139847fdae5..8192a9020f7 100644
--- a/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.hash/hash.pass.cpp
@@ -21,7 +21,7 @@
 #include <type_traits>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::hash<std::type_index> H;
     static_assert((std::is_same<typename H::argument_type, std::type_index>::value), "" );
@@ -29,4 +29,6 @@ int main()
 
     std::type_index t1 = typeid(int);
     assert(std::hash<std::type_index>()(t1) == t1.hash_code());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
index cafeebb0930..c133130f10e 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/ctor.pass.cpp
@@ -16,9 +16,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_info const & info = typeid(int);
     std::type_index t1(info);
     assert(t1.name() == info.name());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
index 210d0ab028c..97f6448b73e 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/eq.pass.cpp
@@ -16,11 +16,13 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1 = typeid(int);
     std::type_index t2 = typeid(int);
     std::type_index t3 = typeid(long);
     assert(t1 == t2);
     assert(t1 != t3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
index f5b6cc35c7d..0619ff75443 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/hash_code.pass.cpp
@@ -15,9 +15,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::type_info& ti = typeid(int);
     std::type_index t1 = typeid(int);
     assert(t1.hash_code() == ti.hash_code());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
index 1f631b7b997..e24b3975e66 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/lt.pass.cpp
@@ -18,7 +18,7 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1 = typeid(int);
     std::type_index t2 = typeid(int);
@@ -41,4 +41,6 @@ int main()
         assert( (t1 >  t3));
         assert( (t1 >= t3));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
index 1b01f52f9f7..ee91629b35c 100644
--- a/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.members/name.pass.cpp
@@ -16,9 +16,11 @@
 #include <string>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     const std::type_info& ti = typeid(int);
     std::type_index t1 = typeid(int);
     assert(std::string(t1.name()) == ti.name());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
index b7fbb6f91cf..72cae39d045 100644
--- a/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.overview/copy_assign.pass.cpp
@@ -15,11 +15,13 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1(typeid(int));
     std::type_index t2(typeid(double));
     assert(t2 != t1);
     t2 = t1;
     assert(t2 == t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
index 9520cd8f67e..df0df2e8c92 100644
--- a/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.overview/copy_ctor.pass.cpp
@@ -15,9 +15,11 @@
 #include <typeindex>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::type_index t1(typeid(int));
     std::type_index t2 = t1;
     assert(t2 == t1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp b/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
index 333e04b1811..e8ce292cca0 100644
--- a/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
+++ b/libcxx/test/std/utilities/type.index/type.index.synopsis/hash_type_index.pass.cpp
@@ -22,7 +22,7 @@
 #include "poisoned_hash_helper.hpp"
 #endif
 
-int main()
+int main(int, char**)
 {
   {
     typedef std::hash<std::type_index> H;
@@ -34,4 +34,6 @@ int main()
     test_hash_enabled_for_type<std::type_index>(std::type_index(typeid(int)));
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utilities.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/allocator.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/hash.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/nullablepointer.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/swappable.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility.requirements/utility.arg.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp b/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
index 5f3b78b7245..1bb2e64c371 100644
--- a/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
+++ b/libcxx/test/std/utilities/utility/as_const/as_const.fail.cpp
@@ -15,7 +15,9 @@
 
 struct S {int i;};
 
-int main()
+int main(int, char**)
 {
     std::as_const(S{});
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp b/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
index 284e5b7b3d6..32d240a0b41 100644
--- a/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/as_const/as_const.pass.cpp
@@ -34,7 +34,7 @@ void test(T& t)
     assert(std::as_const<const volatile T>(t) == t);
 }
 
-int main()
+int main(int, char**)
 {
     int i = 3;
     double d = 4.0;
@@ -42,4 +42,6 @@ int main()
     test(i);
     test(d);
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/declval/declval.pass.cpp b/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
index b298d58a018..6509fd4377c 100644
--- a/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
+++ b/libcxx/test/std/utilities/utility/declval/declval.pass.cpp
@@ -21,11 +21,13 @@ class A
     A& operator=(const A&);
 };
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     static_assert((std::is_same<decltype(std::declval<A>()), A&&>::value), "");
 #else
     static_assert((std::is_same<decltype(std::declval<A>()), A&>::value), "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp b/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
index 1defcbfb339..41e8abb43e5 100644
--- a/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
+++ b/libcxx/test/std/utilities/utility/exchange/exchange.pass.cpp
@@ -39,7 +39,7 @@ TEST_CONSTEXPR bool test_constexpr() {
 
 
 
-int main()
+int main(int, char**)
 {
     {
     int v = 12;
@@ -80,4 +80,6 @@ int main()
 #if TEST_STD_VER > 17
     static_assert(test_constexpr());
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward.fail.cpp b/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
index a689b1d0dfe..4efc1b6aad1 100644
--- a/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward.fail.cpp
@@ -19,7 +19,7 @@ struct A
 A source() {return A();}
 const A csource() {return A();}
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -49,4 +49,6 @@ int main()
         A a;
         std::forward(a); // expected-error {{no matching function for call to 'forward'}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward.pass.cpp b/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
index 394c016e2c3..b2f7c960392 100644
--- a/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward.pass.cpp
@@ -41,7 +41,7 @@ constexpr bool test_constexpr_forward() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     A a;
     const A ca = A();
@@ -87,4 +87,6 @@ int main()
     static_assert(std::forward<const int&>(i2) == 42, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp b/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
index c5a2507a750..522382dc7ed 100644
--- a/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/forward_03.pass.cpp
@@ -28,7 +28,7 @@ struct eight {one _[8];};
 one test(A&);
 two test(const A&);
 
-int main()
+int main(int, char**)
 {
     A a;
     const A ca = A();
@@ -54,4 +54,6 @@ int main()
     static_assert(sizeof(test(std::forward<const A>(ca))) == 2, "");
     static_assert(sizeof(test(std::forward<const A>(csource()))) == 2, "");
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move.fail.cpp b/libcxx/test/std/utilities/utility/forward/move.fail.cpp
index bd8fd46a97e..86f3cc3e5d0 100644
--- a/libcxx/test/std/utilities/utility/forward/move.fail.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move.fail.cpp
@@ -24,10 +24,12 @@ const move_only csource() {return move_only();}
 
 void test(move_only) {}
 
-int main()
+int main(int, char**)
 {
     move_only a;
     const move_only ca = move_only();
 
     test(std::move(ca)); // c
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move.pass.cpp b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
index c98efa1c345..3db61cda27d 100644
--- a/libcxx/test/std/utilities/utility/forward/move.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move.pass.cpp
@@ -62,7 +62,7 @@ constexpr bool test_constexpr_move() {
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     { // Test return type and noexcept.
         static_assert(std::is_same<decltype(std::move(x)), int&&>::value, "");
@@ -117,4 +117,6 @@ int main()
         static_assert(std::move(y) == 42, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp b/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
index 52a276c2412..11ea3c58f09 100644
--- a/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
+++ b/libcxx/test/std/utilities/utility/forward/move_if_noexcept.pass.cpp
@@ -39,7 +39,7 @@ struct legacy
     legacy(const legacy&);
 };
 
-int main()
+int main(int, char**)
 {
     int i = 0;
     const int ci = 0;
@@ -71,4 +71,6 @@ int main()
     static_assert(i2 == 23, "" );
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp b/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
index 9c8dbedcc65..42e80866562 100644
--- a/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
+++ b/libcxx/test/std/utilities/utility/operators/rel_ops.pass.cpp
@@ -32,7 +32,7 @@ operator < (const A& x, const A& y)
     return x.data_ < y.data_;
 }
 
-int main()
+int main(int, char**)
 {
     using namespace std::rel_ops;
     A a1(1);
@@ -45,4 +45,6 @@ int main()
     assert(a1 <= a2);
     assert(a2 >= a2);
     assert(a2 >= a1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
index e14a1c46a7b..e186514f0ea 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.fail.cpp
@@ -17,7 +17,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -26,4 +26,6 @@ int main()
         assert(std::get<1>(p) == 4);
         std::get<0>(p) = 5;
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
index 2b164deb457..d9747b337e8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const.pass.cpp
@@ -19,7 +19,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -36,4 +36,6 @@ int main()
         static_assert(std::get<1>(p1) == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
index 05c81a23b58..a477c5150ab 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_const_rv.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::pair<std::unique_ptr<int>, short> P;
@@ -62,4 +62,6 @@ int main()
     static_assert(std::get<1>(std::move(p1)) == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
index 45fb7aa7942..6119cd5c8ce 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_non_const.pass.cpp
@@ -29,7 +29,7 @@ struct S {
 constexpr std::pair<int, int> getP () { return { 3, 4 }; }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -49,4 +49,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
index 9ca7b4df6df..e0ce55bba90 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/get_rv.pass.cpp
@@ -20,7 +20,7 @@
 #include <memory>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, short> P;
@@ -28,4 +28,6 @@ int main()
         std::unique_ptr<int> ptr = std::get<0>(std::move(p));
         assert(*ptr == 3);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
index 99fb2cd2259..f2d3359e7a5 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type.pass.cpp
@@ -16,7 +16,7 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     {
@@ -81,4 +81,6 @@ int main()
     static_assert(std::get<int>(std::move(p)) == 1, "");
     static_assert(std::get<const int>(std::move(p)) == 2, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
index bba71cb8de2..dce209921b8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type1.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     auto t1 = std::make_pair<int, double> ( 42, 3.4 );
     assert (( std::get<cf>(t1) == cf {1,2} ));  // no such type
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
index c79e0788ce0..4c2ea88e6b8 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type2.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::complex<float> cf;
     auto t1 = std::make_pair<int, int> ( 42, 43 );
     assert ( std::get<int>(t1) == 42 ); // two ints
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
index 4787d0e2edd..e30b787e1fd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/pairs.by.type3.fail.cpp
@@ -12,9 +12,11 @@
 
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     typedef std::unique_ptr<int> upint;
     std::pair<upint, int> t(upint(new int(4)), 23);
     upint p = std::get<upint>(t);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
index ba571fda1eb..e53ca898d26 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.fail.cpp
@@ -14,8 +14,10 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<int, short> T;
     std::tuple_element<2, T>::type foo; // expected-error@utility:* {{Index out of bounds in std::tuple_element<std::pair<T1, T2>>}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
index 4ba58143442..1e41e3fda5d 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_element.pass.cpp
@@ -47,8 +47,10 @@ void test()
     }
 }
 
-int main()
+int main(int, char**)
 {
     test<int, short>();
     test<int*, char>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
index a88b8459692..3b95b4749dd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.astuple/tuple_size.pass.cpp
@@ -14,7 +14,7 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -32,4 +32,6 @@ int main()
         typedef std::pair<int, short> const volatile P1;
         static_assert((std::tuple_size<P1>::value == 2), "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
index 72eb312081e..98f864caf1f 100644
--- a/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pair.piecewise/piecewise_construct.pass.cpp
@@ -41,7 +41,7 @@ public:
     unsigned get_u2() const {return u2_;}
 };
 
-int main()
+int main(int, char**)
 {
     std::pair<A, B> p(std::piecewise_construct,
                       std::make_tuple(4, 'a'),
@@ -51,4 +51,6 @@ int main()
     assert(p.second.get_d() == 3.5);
     assert(p.second.get_u1() == 6u);
     assert(p.second.get_u2() == 2u);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
index 11403c91de0..0f22808de48 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/U_V.pass.cpp
@@ -46,7 +46,7 @@ struct ImplicitT {
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, short*> P;
@@ -96,4 +96,6 @@ int main()
         static_assert(p.second.value == 43, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
index 5af432b991a..834d73dd7f5 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_const_pair_U_V.pass.cpp
@@ -20,7 +20,7 @@
 #include "archetypes.hpp"
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -48,4 +48,6 @@ int main()
        assert(p.second.value == -42);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
index db671a1501a..f4dfe5e1b94 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair.pass.cpp
@@ -49,7 +49,7 @@ int CountAssign::moved = 0;
 struct Incomplete;
 extern Incomplete inc_obj;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<CopyAssignable, short> P;
@@ -94,6 +94,8 @@ int main()
         P p(42, inc_obj);
         assert(&p.second == &inc_obj);
     }
+
+  return 0;
 }
 
 struct Incomplete {};
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
index 53cc49183f7..47f85eaa6b4 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_pair_cxx03.pass.cpp
@@ -27,7 +27,7 @@ private:
 struct Incomplete;
 extern Incomplete inc_obj;
 
-int main()
+int main(int, char**)
 {
     {
     // Test that we don't constrain the assignment operator in C++03 mode.
@@ -42,6 +42,8 @@ int main()
     P p(42, inc_obj);
     assert(&p.second == &inc_obj);
     }
+
+  return 0;
 }
 
 struct Incomplete {};
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
index 91427ca7f2c..b4f0c01094d 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair.pass.cpp
@@ -45,7 +45,7 @@ struct CountAssign {
 int CountAssign::copied = 0;
 int CountAssign::moved = 0;
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<int>, int> P;
@@ -92,4 +92,6 @@ int main()
         assert(CountAssign::moved == 1);
         assert(CountAssign::copied == 0);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
index 7248c2ffa02..0be0a4e9526 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp
@@ -29,7 +29,7 @@ struct Derived
 {
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<Derived>, short> P1;
@@ -55,4 +55,6 @@ int main()
        assert(p.first == 42);
        assert(p.second.value == -42);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
index fcaa44849cb..e147d755856 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second.pass.cpp
@@ -46,7 +46,7 @@ void test_sfinae() {
     static_assert(test_convertible<P2,   T2,   T1Arg>() == CanConvert, "");
 }
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -94,4 +94,6 @@ int main()
         static_assert(p.second == 10, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
index 4759303d663..880179723fb 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_first_const_second_cxx03.pass.cpp
@@ -24,7 +24,7 @@ public:
     bool operator==(const A& a) const {return data_ == a.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -38,4 +38,6 @@ int main()
         assert(p.first == A(1));
         assert(p.second == 2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
index c9c733d8cbe..ce1e86c1a8b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V.pass.cpp
@@ -53,7 +53,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, int> P1;
@@ -177,4 +177,6 @@ int main()
         static_assert(p2.second.value == 101, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
index 8a3fca758eb..9f6498806f3 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/const_pair_U_V_cxx03.pass.cpp
@@ -15,7 +15,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -25,4 +25,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
index bee96000e52..81a32901abe 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/copy_ctor.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -35,4 +35,6 @@ int main()
         static_assert(p2.second == 4, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
index b3a248c8862..70557aa923c 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default-sfinae.pass.cpp
@@ -139,7 +139,7 @@ void test_illformed_default()
 }
 
 
-int main()
+int main(int, char**)
 {
     {
         // Check that pair<T, U> can still be used even if
@@ -160,4 +160,6 @@ int main()
         test_is_default_constructible<int>();
         test_is_default_constructible<DefaultSFINAES<int>>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
index 9a07814b123..dc1f37b666b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/default.pass.cpp
@@ -28,7 +28,7 @@
 #include "test_macros.h"
 #include "archetypes.hpp"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<float, short*> P;
@@ -51,4 +51,6 @@ int main()
         static_assert(!std::is_default_constructible<P2>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
index df9cbc75756..268ec4294c7 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/dtor.pass.cpp
@@ -26,10 +26,12 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
   static_assert((std::is_trivially_destructible<
       std::pair<int, float> >::value), "");
   static_assert((!std::is_trivially_destructible<
       std::pair<int, std::string> >::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
index 4b7529388cd..ca5a728844e 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/implicit_deduction_guides.pass.cpp
@@ -39,7 +39,7 @@
 // (6)  explicit pair(pair<U1, U2> const&) -> pair<U1, U2>
 // (7)  pair(pair<U1, U2> &&) -> pair<U1, U2>
 // (8)  explicit pair(pair<U1, U2> &&) -> pair<U1, U2>
-int main()
+int main(int, char**)
 {
   using E = ExplicitTestTypes::TestType;
   static_assert(!std::is_convertible<E const&, E>::value, "");
@@ -76,4 +76,6 @@ int main()
     std::pair p1(std::move(p));
     ASSERT_SAME_TYPE(decltype(p1), std::pair<std::string, E>);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
index 92a0aa42b14..53d81ac7aac 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/move_ctor.pass.cpp
@@ -25,7 +25,7 @@ struct Dummy {
   Dummy(Dummy &&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -40,4 +40,6 @@ int main()
         static_assert(!std::is_copy_constructible<P>::value, "");
         static_assert(std::is_move_constructible<P>::value, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
index 325499eafaf..88d0f964939 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/not_constexpr_cxx11.fail.cpp
@@ -27,7 +27,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         using P = std::pair<int, int>;
@@ -53,4 +53,6 @@ int main()
         constexpr P U_V = {42, 101}; // expected-error {{must be initialized by a constant expression}}
         constexpr P pair_U_V = other; // expected-error {{must be initialized by a constant expression}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
index 3c93eeb3dca..26b02f383ad 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/piecewise.pass.cpp
@@ -21,7 +21,7 @@
 #include <utility>
 
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, int*> P1;
@@ -32,4 +32,6 @@ int main()
         assert(p3.first == P1(3, nullptr));
         assert(p3.second == P2(nullptr, 4));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
index b38ca2a3b72..0e3d9a1cb70 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/rv_pair_U_V.pass.cpp
@@ -63,7 +63,7 @@ struct ImplicitT {
   int value;
 };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<std::unique_ptr<Derived>, int> P1;
@@ -173,4 +173,6 @@ int main()
         static_assert(p2.second.value == 43, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
index 48ea5fac6e9..db174e829bd 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/special_member_generation_test.pass.cpp
@@ -120,7 +120,9 @@ void test_assignment_operator_exists() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_constructors_exist();
   test_assignment_operator_exists();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
index 58a5c29326a..faaae1bc255 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/swap.pass.cpp
@@ -24,7 +24,7 @@ struct S {
     bool operator==(int x) const { return i == x; }
     };
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -46,4 +46,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
index e4b444a349f..6841f286553 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/trivial_copy_move.pass.cpp
@@ -26,7 +26,7 @@ struct Dummy {
   Dummy(Dummy &&) = default;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<int, short> P;
     {
@@ -52,4 +52,6 @@ int main()
 #endif
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
index abda1d8c3b9..25108de5bbe 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.pair/types.pass.cpp
@@ -17,9 +17,11 @@
 #include <utility>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     typedef std::pair<float, short*> P;
     static_assert((std::is_same<P::first_type, float>::value), "");
     static_assert((std::is_same<P::second_type, short*>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
index 3b994dfd4df..12d6ab01917 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/comparison.pass.cpp
@@ -23,7 +23,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P;
@@ -94,4 +94,6 @@ int main()
         static_assert( (p1 >= p2), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
index 3586243f8ba..dff26e57f0b 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/make_pair.pass.cpp
@@ -17,7 +17,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -49,4 +49,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp b/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
index 62fa9424794..87432767217 100644
--- a/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/pairs/pairs.spec/non_member_swap.pass.cpp
@@ -16,7 +16,7 @@
 #include <utility>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::pair<int, short> P1;
@@ -28,4 +28,6 @@ int main()
         assert(p2.first == 3);
         assert(p2.second == 4);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/synopsis.pass.cpp b/libcxx/test/std/utilities/utility/synopsis.pass.cpp
index 90c5e32186d..5a703e1b2e5 100644
--- a/libcxx/test/std/utilities/utility/synopsis.pass.cpp
+++ b/libcxx/test/std/utilities/utility/synopsis.pass.cpp
@@ -13,9 +13,11 @@
 
 #include <utility>
 
-int main()
+int main(int, char**)
 {
     std::initializer_list<int> x;
     (void)x;
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp b/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
index 53fa3cf6655..155b2c0eb21 100644
--- a/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.inplace/inplace.pass.cpp
@@ -42,7 +42,7 @@ constexpr bool check_tag(Up) {
         && std::is_same<Tp, Up>::value;
 }
 
-int main() {
+int main(int, char**) {
     // test in_place_t
     {
         using T = std::in_place_t;
@@ -70,4 +70,6 @@ int main() {
         static_assert(check_tag<T2>(std::in_place_index<1>));
         static_assert(check_tag<T3>(std::in_place_index<static_cast<size_t>(-1)>));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp b/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
index 9dda5a42c1f..f52af4cb896 100644
--- a/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp
@@ -62,7 +62,7 @@ constexpr bool can_swap() {
 }
 #endif
 
-int main()
+int main(int, char**)
 {
 
     {
@@ -99,4 +99,6 @@ int main()
         static_assert(noexcept(std::swap(nm, nm)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp b/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
index 202e8d33f23..015e85a0135 100644
--- a/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
+++ b/libcxx/test/std/utilities/utility/utility.swap/swap_array.pass.cpp
@@ -54,7 +54,7 @@ constexpr bool can_swap() {
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
         int i[3] = {1, 2, 3};
@@ -97,4 +97,6 @@ int main()
         static_assert(noexcept(std::swap(ma, ma)), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp b/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
index 1585e1745ba..cb66771fc43 100644
--- a/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.bad_variant_access/bad_variant_access.pass.cpp
@@ -35,11 +35,13 @@ public:
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   static_assert(std::is_base_of<std::exception, std::bad_variant_access>::value,
                 "");
   static_assert(noexcept(std::bad_variant_access{}), "must be noexcept");
   static_assert(noexcept(std::bad_variant_access{}.what()), "must be noexcept");
   std::bad_variant_access ex;
   assert(ex.what());
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
index 0c118a0f5f5..8002e55766c 100644
--- a/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.general/nothing_to_do.pass.cpp
@@ -7,4 +7,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
index 505a8cb8e65..5210c5f9d84 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_if_index.pass.cpp
@@ -125,7 +125,9 @@ void test_get_if() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_get_if();
   test_get_if();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
index 3cb0fc7054e..e7c9671f95c 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_if_type.pass.cpp
@@ -123,7 +123,9 @@ void test_get_if() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_get_if();
   test_get_if();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
index a5a629adb96..5519c4263b7 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_index.pass.cpp
@@ -285,10 +285,12 @@ void test_throws_for_all_value_categories() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_lvalue_get();
   test_lvalue_get();
   test_rvalue_get();
   test_const_rvalue_get();
   test_throws_for_all_value_categories();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
index b4cae102705..76bbbb026e4 100644
--- a/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/get_type.pass.cpp
@@ -285,10 +285,12 @@ void test_throws_for_all_value_categories() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_const_lvalue_get();
   test_lvalue_get();
   test_rvalue_get();
   test_const_rvalue_get();
   test_throws_for_all_value_categories();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp b/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
index 3e9cfbe9c47..b37462069df 100644
--- a/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.get/holds_alternative.pass.cpp
@@ -17,7 +17,7 @@
 #include "test_macros.h"
 #include <variant>
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int>;
     constexpr V v;
@@ -34,4 +34,6 @@ int main() {
     const V v;
     ASSERT_NOEXCEPT(std::holds_alternative<int>(v));
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp b/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
index 404f3e7e5b4..7e9ffbfa06e 100644
--- a/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.hash/enabled_hash.pass.cpp
@@ -17,6 +17,8 @@
 
 #include "poisoned_hash_helper.hpp"
 
-int main() {
+int main(int, char**) {
   test_library_hash_specializations_available();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
index 5acf168ad8c..edda8d21a24 100644
--- a/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.hash/hash.pass.cpp
@@ -150,9 +150,11 @@ void test_hash_variant_enabled() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_hash_variant();
   test_hash_variant_duplicate_elements();
   test_hash_monostate();
   test_hash_variant_enabled();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
index f7db0d86bee..48d5e14e260 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.fail.cpp
@@ -25,7 +25,9 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
     using V = std::variant<int, void *, const void *, long double>;
     std::variant_alternative<4, V>::type foo;  // expected-error@variant:* {{Index out of bounds in std::variant_alternative<>}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
index 841f65cb127..7db07b6b0d4 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.pass.cpp
@@ -55,7 +55,7 @@ template <class V, size_t I, class E> void test() {
                 "");
 }
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, void *, const void *, long double>;
     test<V, 0, int>();
@@ -73,4 +73,6 @@ int main() {
     test<V, 4, long double>();
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp b/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
index f7e200b241a..fb027fb6380 100644
--- a/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.helpers/variant_size.pass.cpp
@@ -36,8 +36,10 @@ template <class V, size_t E> void test() {
                 "");
 };
 
-int main() {
+int main(int, char**) {
   test<std::variant<>, 0>();
   test<std::variant<void *>, 1>();
   test<std::variant<long, long, void *, double>, 4>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp b/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
index 2df4b2bacf5..255f6d0342e 100644
--- a/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.monostate.relops/relops.pass.cpp
@@ -23,7 +23,7 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   using M = std::monostate;
   constexpr M m1{};
   constexpr M m2{};
@@ -51,4 +51,6 @@ int main() {
     static_assert((m1 != m2) == false, "");
     ASSERT_NOEXCEPT(m1 != m2);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp b/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
index 1d7bcaca4db..1ba75a77907 100644
--- a/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.monostate/monostate.pass.cpp
@@ -16,7 +16,7 @@
 #include <type_traits>
 #include <variant>
 
-int main() {
+int main(int, char**) {
   using M = std::monostate;
   static_assert(std::is_trivially_default_constructible<M>::value, "");
   static_assert(std::is_trivially_copy_constructible<M>::value, "");
@@ -24,4 +24,6 @@ int main() {
   static_assert(std::is_trivially_destructible<M>::value, "");
   constexpr M m{};
   ((void)m);
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
index 1950b5a383d..ed32215ffdc 100644
--- a/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops.pass.cpp
@@ -269,7 +269,9 @@ void test_relational() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_equality();
   test_relational();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
index d03a6b5d5b1..e46893465bc 100644
--- a/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.relops/relops_bool_conv.fail.cpp
@@ -72,7 +72,7 @@ inline constexpr MyBoolExplicit operator>=(const ComparesToMyBoolExplicit& LHS,
 }
 
 
-int main() {
+int main(int, char**) {
   using V = std::variant<int, ComparesToMyBoolExplicit>;
   V v1(42);
   V v2(101);
@@ -84,4 +84,6 @@ int main() {
   (void)(v1 <= v2); // expected-note {{here}}
   (void)(v1 > v2); // expected-note {{here}}
   (void)(v1 >= v2); // expected-note {{here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp b/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
index aadda7eacbb..310b6980c1a 100644
--- a/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.synopsis/variant_npos.pass.cpp
@@ -15,6 +15,8 @@
 
 #include <variant>
 
-int main() {
+int main(int, char**) {
   static_assert(std::variant_npos == static_cast<std::size_t>(-1), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
index 67deb3f2c62..6a4bb048627 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/T.pass.cpp
@@ -254,10 +254,12 @@ void test_T_assignment_performs_assignment() {
 #endif // TEST_HAS_NO_EXCEPTIONS
 }
 
-int main() {
+int main(int, char**) {
   test_T_assignment_basic();
   test_T_assignment_performs_construction();
   test_T_assignment_performs_assignment();
   test_T_assignment_noexcept();
   test_T_assignment_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
index 6a59989ddad..c36375cf299 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/copy.pass.cpp
@@ -590,7 +590,7 @@ void test_constexpr_copy_assignment() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_copy_assignment_empty_empty();
   test_copy_assignment_non_empty_empty();
   test_copy_assignment_empty_non_empty();
@@ -599,4 +599,6 @@ int main() {
   test_copy_assignment_sfinae();
   test_copy_assignment_not_noexcept();
   test_constexpr_copy_assignment();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
index 833883d294f..c213af4b2e7 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.assign/move.pass.cpp
@@ -506,7 +506,7 @@ void test_constexpr_move_assignment() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_move_assignment_empty_empty();
   test_move_assignment_non_empty_empty();
   test_move_assignment_empty_non_empty();
@@ -515,4 +515,6 @@ int main() {
   test_move_assignment_sfinae();
   test_move_assignment_noexcept();
   test_constexpr_move_assignment();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
index 7357b9b56c0..4ebfe052de1 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/T.pass.cpp
@@ -126,8 +126,10 @@ void test_T_ctor_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_T_ctor_basic();
   test_T_ctor_noexcept();
   test_T_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
index b6471052f64..00c94ee33c3 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/copy.pass.cpp
@@ -260,7 +260,7 @@ void test_constexpr_copy_ctor() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_copy_ctor_basic();
   test_copy_ctor_valueless_by_exception();
   test_copy_ctor_sfinae();
@@ -274,4 +274,6 @@ int main() {
   (void) v2;
 }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
index ec6eb289ba6..1766ee1dbc0 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/default.pass.cpp
@@ -122,9 +122,11 @@ void test_default_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_default_ctor_basic();
   test_default_ctor_sfinae();
   test_default_ctor_noexcept();
   test_default_ctor_throws();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
index a268adcea50..cb7d68a659f 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_args.pass.cpp
@@ -104,7 +104,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
index 9c7e3faf862..4b78bf5690a 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_index_init_list_args.pass.cpp
@@ -110,7 +110,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
index 05b2a29ce8f..ab8fe068831 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_args.pass.cpp
@@ -114,7 +114,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
index c3f3e58d346..4061cfb2528 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/in_place_type_init_list_args.pass.cpp
@@ -111,7 +111,9 @@ void test_ctor_basic() {
   }
 }
 
-int main() {
+int main(int, char**) {
   test_ctor_basic();
   test_ctor_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
index ecb4a720755..f146e16d3c0 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.ctor/move.pass.cpp
@@ -331,10 +331,12 @@ void test_constexpr_move_ctor() {
 #endif // > C++17
 }
 
-int main() {
+int main(int, char**) {
   test_move_ctor_basic();
   test_move_ctor_valueless_by_exception();
   test_move_noexcept();
   test_move_ctor_sfinae();
   test_constexpr_move_ctor();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
index 8ced5321b69..b26ab0c29bf 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.dtor/dtor.pass.cpp
@@ -44,7 +44,7 @@ struct TDtor {
 static_assert(!std::is_trivially_copy_constructible<TDtor>::value, "");
 static_assert(std::is_trivially_destructible<TDtor>::value, "");
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long, TDtor>;
     static_assert(std::is_trivially_destructible<V>::value, "");
@@ -71,4 +71,6 @@ int main() {
     assert(NonTDtor::count == 0);
     assert(NonTDtor1::count == 1);
   }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
index ea84ac94072..b688c8e7a54 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_args.pass.cpp
@@ -159,7 +159,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
index 13e3c927c28..9d96a1dc272 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_index_init_list_args.pass.cpp
@@ -92,7 +92,9 @@ void test_basic() {
   assert(&ref3 == &std::get<1>(v));
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
index 7c9034f10a7..0719f5e7bdc 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_args.pass.cpp
@@ -159,7 +159,9 @@ void test_basic() {
 #endif
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
index 85cd25d04de..49839eda4f3 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.mod/emplace_type_init_list_args.pass.cpp
@@ -92,7 +92,9 @@ void test_basic() {
   assert(&ref3 == &std::get<InitList>(v));
 }
 
-int main() {
+int main(int, char**) {
   test_basic();
   test_emplace_sfinae();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
index 0afa10138e3..6d463ad2788 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/index.pass.cpp
@@ -25,7 +25,7 @@
 #include "variant_test_helpers.hpp"
 
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long>;
     constexpr V v;
@@ -57,4 +57,6 @@ int main() {
     assert(v.index() == std::variant_npos);
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
index 147f380a19f..2cb730cb0ff 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.status/valueless_by_exception.pass.cpp
@@ -25,7 +25,7 @@
 #include "variant_test_helpers.hpp"
 
 
-int main() {
+int main(int, char**) {
   {
     using V = std::variant<int, long>;
     constexpr V v;
@@ -50,4 +50,6 @@ int main() {
     assert(v.valueless_by_exception());
   }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
index e05cd13e69f..4e273f52e5e 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant.swap/swap.pass.cpp
@@ -589,10 +589,12 @@ void test_swap_noexcept() {
 template class std::variant<int, NotSwappable>;
 #endif
 
-int main() {
+int main(int, char**) {
   test_swap_valueless_by_exception();
   test_swap_same_alternative();
   test_swap_different_alternatives();
   test_swap_sfinae();
   test_swap_noexcept();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
index a9caeb8b2db..ce79e9c4254 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_array.fail.cpp
@@ -23,10 +23,12 @@
 #include "variant_test_helpers.hpp"
 #include "test_convertible.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, int[]> v; // expected-note {{requested here}}
     std::variant<int, int[42]> v2; // expected-note {{requested here}}
     std::variant<int, int[][42]> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
index 85a10eff9af..3b93cb0ab70 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_empty.fail.cpp
@@ -18,8 +18,10 @@
 #include "test_macros.h"
 #include "variant_test_helpers.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 1 {{static_assert failed}}
     std::variant<> v; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
index e659f47600a..7c2c4669083 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_reference.fail.cpp
@@ -18,10 +18,12 @@
 #include "test_macros.h"
 #include "variant_test_helpers.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, int&> v; // expected-note {{requested here}}
     std::variant<int, const int &> v2; // expected-note {{requested here}}
     std::variant<int, int&&> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp b/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
index ce0675d73c6..27e9c399f8d 100644
--- a/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
+++ b/libcxx/test/std/utilities/variant/variant.variant/variant_void.fail.cpp
@@ -23,10 +23,12 @@
 #include "variant_test_helpers.hpp"
 #include "test_convertible.hpp"
 
-int main()
+int main(int, char**)
 {
     // expected-error@variant:* 3 {{static_assert failed}}
     std::variant<int, void> v; // expected-note {{requested here}}
     std::variant<int, const void> v2; // expected-note {{requested here}}
     std::variant<const volatile void, int> v3; // expected-note {{requested here}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp b/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
index 198f310e9af..15a1de9842c 100644
--- a/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
+++ b/libcxx/test/std/utilities/variant/variant.visit/visit.pass.cpp
@@ -310,10 +310,12 @@ void test_caller_accepts_nonconst() {
   std::visit(Visitor{}, v);
 }
 
-int main() {
+int main(int, char**) {
   test_call_operator_forwarding();
   test_argument_forwarding();
   test_constexpr();
   test_exceptions();
   test_caller_accepts_nonconst();
+
+  return 0;
 }