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

175 files changed, 525 insertions, 175 deletions

diff --git a/libcxx/test/std/iterators/iterator.container/data.pass.cpp b/libcxx/test/std/iterators/iterator.container/data.pass.cpp
index ab80c1cf5ca..952dc687083 100644
--- a/libcxx/test/std/iterators/iterator.container/data.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/data.pass.cpp
@@ -61,7 +61,7 @@ void test_const_array( const T (&array)[Sz] )
     assert ( std::data(array) == &array[0]);
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::array<int, 1> a; a[0] = 3;
@@ -83,4 +83,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
index 1cd16ad9a37..08014776c9d 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.array.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     int c[5];
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
index 4ac2e1335ce..153ea13b643 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.container.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::vector<int> c;
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp b/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
index dcdd89a3135..5dafb5119fe 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.initializer_list.fail.cpp
@@ -20,8 +20,10 @@
 
 #include "test_macros.h"
 
-int main ()
+int main(int, char**)
 {
     std::initializer_list<int> c = { 4 };
     std::empty(c);  // expected-error {{ignoring return value of function declared with 'nodiscard' attribute}}
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/empty.pass.cpp b/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
index b792e006658..5c46cd6fbf0 100644
--- a/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/empty.pass.cpp
@@ -60,7 +60,7 @@ void test_const_array( const T (&array)[Sz] )
     assert (!std::empty(array));
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::list<int>   l; l.push_back(2);
@@ -85,4 +85,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.container/size.pass.cpp b/libcxx/test/std/iterators/iterator.container/size.pass.cpp
index 5b78afa2669..db215b8544f 100644
--- a/libcxx/test/std/iterators/iterator.container/size.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.container/size.pass.cpp
@@ -63,7 +63,7 @@ void test_const_array( const T (&array)[Sz] )
     assert ( std::size(array) == Sz );
 }
 
-int main()
+int main(int, char**)
 {
     std::vector<int> v; v.push_back(1);
     std::list<int>   l; l.push_back(2);
@@ -87,4 +87,6 @@ int main()
 
     static constexpr int arrA [] { 1, 2, 3 };
     test_const_array ( arrA );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
index e922a4bfa46..b5929ca8c10 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.basic/iterator.pass.cpp
@@ -72,10 +72,12 @@ test5()
     static_assert((std::is_same<typename It::iterator_category, std::input_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test2<A>();
     test3<A>();
     test4<A>();
     test5<A>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
index 6382d06c74b..45408056370 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/advance.pass.cpp
@@ -42,7 +42,7 @@ constepxr_test(It i, typename std::iterator_traits<It>::difference_type n, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -68,4 +68,6 @@ int main()
     static_assert( constepxr_test(s+5, -5, s), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
index 86fcfbc5853..bd1b02a484d 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/distance.pass.cpp
@@ -37,7 +37,7 @@ constexpr_test(It first, It last, typename std::iterator_traits<It>::difference_
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -57,4 +57,6 @@ int main()
     static_assert( constexpr_test(s, s+10, 10), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
index ad99aed99b5..87f79fbd32b 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/next.pass.cpp
@@ -51,7 +51,7 @@ constexpr_test(It i, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -83,4 +83,6 @@ int main()
     static_assert( constexpr_test(s, s+1), "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
index b7d99391723..2ee0444ce14 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.operations/prev.pass.cpp
@@ -49,7 +49,7 @@ constexpr_test(It i, It x)
 }
 #endif
 
-int main()
+int main(int, char**)
 {
     {
     const char* s = "1234567890";
@@ -74,4 +74,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
index 246aeb5e8bb..5abf59bf3de 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_pointer.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<const A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<It::pointer, const A*>::value), "");
     static_assert((std::is_same<It::reference, const A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
index 774609e1cc1..358abb619b1 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/const_volatile_pointer.pass.cpp
@@ -16,7 +16,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<const volatile A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -24,4 +24,6 @@ int main()
     static_assert((std::is_same<It::pointer, const volatile A*>::value), "");
     static_assert((std::is_same<It::reference, const volatile A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
index 5c5c07d442d..728909e693c 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.fail.cpp
@@ -63,7 +63,7 @@ struct NotAnIteratorNoCategory
 //     typedef std::forward_iterator_tag iterator_category;
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::iterator_traits<NotAnIteratorEmpty> T;
@@ -118,4 +118,6 @@ int main()
     typedef T::reference         RT; // expected-error-re {{no type named 'reference' in 'std::{{.+}}::iterator_traits<{{.+}}>}}
     typedef T::iterator_category CT; // expected-error-re {{no type named 'iterator_category' in 'std::{{.+}}::iterator_traits<{{.+}}>}}
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
index 81dca5186ec..35fc877f206 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/empty.pass.cpp
@@ -30,8 +30,10 @@ public:
     static const bool value = sizeof(test<T>(0)) == 1;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<not_an_iterator> It;
     static_assert(!(has_value_type<It>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
index 1c8d11eb151..1e4d87c757c 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/iterator.pass.cpp
@@ -32,7 +32,7 @@ struct test_iterator
     typedef std::forward_iterator_tag iterator_category;
 };
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<test_iterator> It;
     static_assert((std::is_same<It::difference_type, int>::value), "");
@@ -40,4 +40,6 @@ int main()
     static_assert((std::is_same<It::pointer, A*>::value), "");
     static_assert((std::is_same<It::reference, A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::forward_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
index 3be21c49a3b..6016f6d4088 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/pointer.pass.cpp
@@ -23,7 +23,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -31,4 +31,6 @@ int main()
     static_assert((std::is_same<It::pointer, A*>::value), "");
     static_assert((std::is_same<It::reference, A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
index ebcc30075af..035360645dc 100644
--- a/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/iterator.traits/volatile_pointer.pass.cpp
@@ -16,7 +16,7 @@
 
 struct A {};
 
-int main()
+int main(int, char**)
 {
     typedef std::iterator_traits<volatile A*> It;
     static_assert((std::is_same<It::difference_type, std::ptrdiff_t>::value), "");
@@ -24,4 +24,6 @@ int main()
     static_assert((std::is_same<It::pointer, volatile A*>::value), "");
     static_assert((std::is_same<It::reference, volatile A&>::value), "");
     static_assert((std::is_same<It::iterator_category, std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
index 6d7f64b9a1e..8380fb6b4e2 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/bidirectional_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::bidirectional_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::bidirectional_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::bidirectional_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
index 753f25c667b..0afdc3eca0a 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/forward_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::forward_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::forward_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::forward_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
index ac517dd6785..26de37448d1 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/input_iterator_tag.pass.cpp
@@ -13,10 +13,12 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::input_iterator_tag tag;
     ((void)tag); // Prevent unused warning
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::input_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
index 1635850cf59..657e6f8ea18 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/output_iterator_tag.pass.cpp
@@ -13,10 +13,12 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::output_iterator_tag tag;
     ((void)tag); // Prevent unused warning
     static_assert((!std::is_base_of<std::input_iterator_tag,
                                     std::output_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
index da2de468176..5448a671573 100644
--- a/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.primitives/std.iterator.tags/random_access_iterator_tag.pass.cpp
@@ -13,7 +13,7 @@
 #include <iterator>
 #include <type_traits>
 
-int main()
+int main(int, char**)
 {
     std::random_access_iterator_tag tag;
     ((void)tag); // Prevent unused warning
@@ -21,4 +21,6 @@ int main()
                                    std::random_access_iterator_tag>::value), "");
     static_assert((!std::is_base_of<std::output_iterator_tag,
                                     std::random_access_iterator_tag>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp b/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
index b87b82f272e..69a27843474 100644
--- a/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
+++ b/libcxx/test/std/iterators/iterator.range/begin-end.fail.cpp
@@ -40,11 +40,13 @@ namespace Foo {
 }
 
 
-int main(){
+int main(int, char**) {
 // Bug #28927 - shouldn't find these via ADL
     TEST_IGNORE_NODISCARD  std::cbegin (Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::cend   (Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::crbegin(Foo::FakeContainer());
     TEST_IGNORE_NODISCARD  std::crend  (Foo::FakeContainer());
+
+  return 0;
 }
 #endif
diff --git a/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp b/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
index a55e0b639d3..7580b463dce 100644
--- a/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.range/begin-end.pass.cpp
@@ -135,7 +135,7 @@ void test_const_array( const T (&array)[Sz] ) {
 #endif
     }
 
-int main(){
+int main(int, char**) {
     std::vector<int> v; v.push_back(1);
     std::list<int> l;   l.push_back(2);
     std::array<int, 1> a; a[0] = 3;
@@ -197,4 +197,6 @@ int main(){
         static_assert ( *std::crbegin(c) == 4, "" );
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/bidirectional.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/forward.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/input.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/iterator.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/iterator.requirements.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/output.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.requirements/random.access.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterator.synopsis/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp b/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
index a6be18d10ec..09b4d76288c 100644
--- a/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
+++ b/libcxx/test/std/iterators/iterators.general/gcc_workaround.pass.cpp
@@ -17,4 +17,6 @@ void f(const std::string &s) { TEST_IGNORE_NODISCARD s.begin(); }
 
 void AppendTo(const std::vector<char> &v) { TEST_IGNORE_NODISCARD v.begin(); }
 
-int main() {}
+int main(int, char**) {
+  return 0;
+}
diff --git a/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/iterators.general/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
index 1bdd5ddef25..9aad14992f5 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.fail.cpp
@@ -17,7 +17,9 @@
 #include <iterator>
 #include <vector>
 
-int main()
+int main(int, char**)
 {
     std::back_insert_iterator<std::vector<int> > i = std::vector<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
index 22f16c2eb09..2aad3fa3f48 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.cons/container.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::back_insert_iterator<C> i(c);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
index ccb22b2bd3d..d36b1ce0630 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
index acb272b4ced..512eb1e56b3 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
index 67772dabc57..2b76a27148e 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/lv_value.pass.cpp
@@ -39,7 +39,9 @@ public:
         {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::vector<Copyable>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
index 93fe8e5fa33..506b7b6f000 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op=/rv_value.pass.cpp
@@ -31,7 +31,9 @@ test(C c)
     assert(c.back() == typename C::value_type());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<std::unique_ptr<int> >());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
index b7f11e0f771..460f723a407 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
index 6c27ce826b2..bd6df64488a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/back.inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
index 47d38438218..470392bc551 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/back.insert.iterator/types.pass.cpp
@@ -52,7 +52,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
index 1ebfd4d3f14..eb3346b2e7a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.fail.cpp
@@ -17,7 +17,9 @@
 #include <iterator>
 #include <list>
 
-int main()
+int main(int, char**)
 {
     std::front_insert_iterator<std::list<int> > i = std::list<int>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
index 80307cb1547..2ef4ba87994 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.cons/container.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::front_insert_iterator<C> i(c);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
index 9b642a7d24e..7c9b09ffd2a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
index 7aa1d6da6a7..ea5c024105b 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
index 555b72d7970..5e1a86d57f0 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/lv_value.pass.cpp
@@ -39,8 +39,10 @@ public:
         {return x.data_ == y.data_;}
 };
 
-int main()
+int main(int, char**)
 {
     test(std::list<Copyable>());
     test(nasty_list<Copyable>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
index ad032a4dde6..450f395d49a 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op=/rv_value.pass.cpp
@@ -29,7 +29,9 @@ test(C c)
     assert(c.front() == typename C::value_type());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<std::unique_ptr<int> >());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
index bf1bf38ad80..3367229b422 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
index f4cc7c984f1..b7436778d11 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/front.inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.front() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::list<int>());
     test(nasty_list<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
index c8609efbe41..c65a8e6f68d 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/front.insert.iterator/types.pass.cpp
@@ -53,7 +53,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
index ae45c90f34e..531dac03c9f 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.cons/test.pass.cpp
@@ -23,8 +23,10 @@ test(C c)
     std::insert_iterator<C> i(c, c.begin());
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
index 22448fddd61..a3148e2e2a4 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/post.pass.cpp
@@ -28,8 +28,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
index c9a8d1ef6e1..99c68609500 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op++/pre.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
index c639a2da169..fe8260b999f 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/lv_value.pass.cpp
@@ -43,7 +43,7 @@ insert3at(C& c, typename C::iterator i,
     c.insert(++i, x3);
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::vector<int> C;
@@ -81,4 +81,6 @@ int main()
     insert3at(c2, c2.begin()+3, 'a', 'b', 'c');
     test(c1, 3, 'a', 'b', 'c', c2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
index 671d6bd496b..7a5addb1ab0 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op=/rv_value.pass.cpp
@@ -52,7 +52,7 @@ struct do_nothing
     void operator()(void*) const {}
 };
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::unique_ptr<int, do_nothing> Ptr;
@@ -91,4 +91,6 @@ int main()
     insert3at(c2, c2.begin()+3, Ptr(x+3), Ptr(x+4), Ptr(x+5));
     test(std::move(c1), 3, Ptr(x+3), Ptr(x+4), Ptr(x+5), c2);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
index d531e5fe3ac..8ef0383eed2 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/insert.iter.op_astrk/test.pass.cpp
@@ -26,8 +26,10 @@ test(C c)
     assert(&r == &i);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
index 05ede8a522f..e1ee829bce7 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/inserter/test.pass.cpp
@@ -27,8 +27,10 @@ test(C c)
     assert(c.back() == 0);
 }
 
-int main()
+int main(int, char**)
 {
     test(std::vector<int>());
     test(nasty_vector<int>());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
index 9d58fc40ccb..1e199b3051b 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/insert.iterator/types.pass.cpp
@@ -58,7 +58,9 @@ test()
     static_assert((std::is_same<typename R::iterator_category, std::output_iterator_tag>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<std::vector<int> >();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/insert.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
index 36dfddd7f02..3a9b467e06f 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/make_move_iterator.pass.cpp
@@ -30,7 +30,7 @@ test(It i)
     assert(std::make_move_iterator(i) == r);
 }
 
-int main()
+int main(int, char**)
 {
     {
     char s[] = "1234567890";
@@ -53,4 +53,6 @@ int main()
     static_assert(iter.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
index 67852259734..e3b881edc9e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/minus.pass.cpp
@@ -33,7 +33,7 @@ test(It l, It r, typename std::iterator_traits<It>::difference_type x)
     assert(r1 - r2 == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s+5), random_access_iterator<char*>(s), 5);
@@ -49,4 +49,6 @@ int main()
     static_assert( it2 - it1 ==  1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
index 63c3e8ed5d4..5e1965e19c2 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.nonmember/plus.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s+5), 5, random_access_iterator<char*>(s+10));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
index 95ab190f11a..1e3244e19b9 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -48,4 +48,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
index 0af1ff83fbf..863e06c0e45 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.+=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
index ce0cb93cff8..3cf76f5daea 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -48,4 +48,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
index f17543335e5..5692f708881 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.-=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -45,4 +45,6 @@ int main()
     static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
index 1e05a50c7f5..ecf8f90ea1e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_eq.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 == r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(input_iterator<char*>(s), input_iterator<char*>(s), true);
@@ -58,4 +58,6 @@ int main()
     static_assert(!(it2 == it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
index e58a57b5088..3da38b37666 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gt.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 > r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), false);
@@ -54,4 +54,6 @@ int main()
     static_assert( (it2 > it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
index e10962f02cf..dceb4115152 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_gte.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 >= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     static_assert( (it2 >= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
index ebe90244e26..675e55f7881 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lt.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 < r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), false);
@@ -54,4 +54,6 @@ int main()
     static_assert(!(it2 < it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
index 72efc481e3f..a2ac0b7a6f7 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_lte.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 <= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(random_access_iterator<char*>(s), random_access_iterator<char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     static_assert(!(it2 <= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
index 69695e56bbb..01a7195d4d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.comp/op_neq.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 != r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "1234567890";
     test(input_iterator<char*>(s), input_iterator<char*>(s), false);
@@ -58,4 +58,6 @@ int main()
     static_assert( (it2 != it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
index 56b99025eeb..b91767b0814 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.fail.cpp
@@ -29,9 +29,11 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
 
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
index dae13100db2..7f31920f76a 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/convert.pass.cpp
@@ -34,7 +34,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -52,4 +52,6 @@ int main()
     static_assert(it2.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
index dfd89df807c..6dfa0d09db9 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/default.pass.cpp
@@ -27,7 +27,7 @@ test()
     (void)r;
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<char*> >();
     test<forward_iterator<char*> >();
@@ -41,4 +41,6 @@ int main()
     (void)it;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
index 0b8ea454089..28648b81534 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.fail.cpp
@@ -23,8 +23,10 @@ test(It i)
     std::move_iterator<It> r = i;
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
index 5832ecbcf80..bed97700e7c 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.const/iter.pass.cpp
@@ -28,7 +28,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s));
@@ -44,4 +44,6 @@ int main()
     static_assert(it.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.conv/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
index 0b6db37e144..38d52329721 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(bidirectional_iterator<char*>(s+1), bidirectional_iterator<char*>(s));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
index c7c00183c7c..e98fb6b0936 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.decr/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(bidirectional_iterator<char*>(s+1), bidirectional_iterator<char*>(s));
@@ -49,4 +49,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
index f37522c13f6..50597a54b0b 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s), input_iterator<char*>(s+1));
@@ -51,4 +51,6 @@ int main()
     static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
index 4bcbdd5792b..101f5cdbc0f 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.incr/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(input_iterator<char*>(s), input_iterator<char*>(s+1));
@@ -51,4 +51,6 @@ int main()
     static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
index d626ff28a38..ecf3b61058b 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.index/difference_type.pass.cpp
@@ -38,7 +38,7 @@ struct do_nothing
     void operator()(void*) const {}
 };
 
-int main()
+int main(int, char**)
 {
     {
         char s[] = "1234567890";
@@ -64,4 +64,6 @@ int main()
     static_assert(it1[5] == '6', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
index 027162b90f0..6024f99fec3 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.ref/op_arrow.pass.cpp
@@ -27,7 +27,7 @@ test(It i)
     assert(r.operator->() == i);
 }
 
-int main()
+int main(int, char**)
 {
     char s[] = "123";
     test(s);
@@ -42,4 +42,6 @@ int main()
     static_assert(it2.operator->() == p + 1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
index 6dfe0a51736..e6e826d8352 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op.star/op_star.pass.cpp
@@ -47,7 +47,7 @@ struct do_nothing
 };
 
 
-int main()
+int main(int, char**)
 {
     {
         A a;
@@ -70,4 +70,6 @@ int main()
     static_assert(*it2 == p[1], "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
index 68fe476ac64..94d012dfb7e 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.fail.cpp
@@ -31,8 +31,10 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
index fbc5320feb5..84fbccb8be6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/move.iter.op=/move_iterator.pass.cpp
@@ -37,7 +37,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -56,4 +56,6 @@ int main()
     static_assert(it2.base() == p, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iter.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
index 9eb4669c3c5..905952f42bd 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/move.iterator/types.pass.cpp
@@ -55,7 +55,7 @@ test()
     static_assert((std::is_same<typename R::iterator_category, typename T::iterator_category>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<input_iterator<char*> >();
     test<forward_iterator<char*> >();
@@ -91,4 +91,6 @@ int main()
         static_assert(std::is_same<It::reference, int&&>::value, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/move.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
index de035fcd3c9..32931eefa91 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/default.pass.cpp
@@ -27,7 +27,7 @@ test()
     (void)r;
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<const char*> >();
     test<random_access_iterator<char*> >();
@@ -40,4 +40,6 @@ int main()
         (void)it;
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
index bbbf1247f47..6130386b0d2 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.fail.cpp
@@ -23,8 +23,10 @@ test(It i)
     std::reverse_iterator<It> r = i;
 }
 
-int main()
+int main(int, char**)
 {
     const char s[] = "123";
     test(s);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
index 47fc29b094a..32cc74f9586 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/iter.pass.cpp
@@ -28,7 +28,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char s[] = "123";
     test(bidirectional_iterator<const char*>(s));
@@ -42,4 +42,6 @@ int main()
         static_assert(it.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
index 02ab54a5986..5a878e4937e 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.fail.cpp
@@ -29,9 +29,11 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
 
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
index db53853dc59..53b82bd4038 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.cons/reverse_iterator.pass.cpp
@@ -34,7 +34,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -50,4 +50,6 @@ int main()
         static_assert(it2.base() == p);
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.conv/tested_elsewhere.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
index 8ad3d79b390..fa7026ddeec 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.make/make_reverse_iterator.pass.cpp
@@ -31,7 +31,7 @@ test(It i)
     assert(r.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     random_access_iterator<const char*>b(s);
@@ -46,5 +46,7 @@ int main()
         static_assert(it1.base() == p, "");
     }
 #endif
+
+  return 0;
 }
 
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
index c67884d9187..f3e74970967 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op!=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 != r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 != it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
index 2232a87f5c5..d7658ccfc99 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
index d2337e2086e..edc74fab504 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op++/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s));
@@ -50,4 +50,6 @@ int main()
         static_assert(*(++std::make_reverse_iterator(p+2)) == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
index eed06f3df9c..9b30f59da93 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -48,4 +48,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
index 5460382133c..229f3ca1188 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op+=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -45,4 +45,6 @@ int main()
         static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
index 35fdf1b1ed8..8b9912c8173 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/post.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(rr.base() == i);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s+2));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
index f0df91777a7..9ccab06e839 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op--/pre.pass.cpp
@@ -30,7 +30,7 @@ test(It i, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "123";
     test(bidirectional_iterator<const char*>(s+1), bidirectional_iterator<const char*>(s+2));
@@ -50,4 +50,6 @@ int main()
         static_assert(*(--std::make_reverse_iterator(p)) == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
index b59095db8a4..0e3a5d36210 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -48,4 +48,6 @@ int main()
         static_assert(it2 == it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
index a484a67a7dd..ab92dc0686f 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op-=/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(&rr == &r);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s+10));
@@ -45,4 +45,6 @@ int main()
         static_assert(it1 == it2, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
index efe3dbf9ccd..820ee006014 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op.star/op_star.pass.cpp
@@ -43,7 +43,7 @@ test(It i, typename std::iterator_traits<It>::value_type x)
     assert(*r == x);
 }
 
-int main()
+int main(int, char**)
 {
     A a;
     test(&a+1, A());
@@ -58,4 +58,6 @@ int main()
         static_assert(*it2 == p[1], "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
index 0580eb09813..071e3ef1050 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.fail.cpp
@@ -31,8 +31,10 @@ test(U u)
 struct base {};
 struct derived {};
 
-int main()
+int main(int, char**)
 {
     derived d;
     test<base*>(&d);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
index e39476a98e9..838bdc917e2 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op=/reverse_iterator.pass.cpp
@@ -37,7 +37,7 @@ test(U u)
 struct Base {};
 struct Derived : Base {};
 
-int main()
+int main(int, char**)
 {
     Derived d;
 
@@ -55,4 +55,6 @@ int main()
         static_assert(it2.base() == p, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
index 066aa769b37..7bd699bb9ea 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.op==/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 == r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(bidirectional_iterator<const char*>(s), bidirectional_iterator<const char*>(s), true);
@@ -54,4 +54,6 @@ int main()
     }
 #endif
 
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
index 2c7574eb454..ce901234809 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opdiff/test.pass.cpp
@@ -33,7 +33,7 @@ test(It1 l, It2 r, std::ptrdiff_t x)
     assert((r1 - r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     char s[3] = {0};
     test(random_access_iterator<const char*>(s), random_access_iterator<char*>(s), 0);
@@ -53,4 +53,6 @@ int main()
         static_assert( it2 - it1 == -1, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
index d32932848cf..86b19e3fc6a 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 > r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 > it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
index b12f7c135d6..de53281202f 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opgt=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 >= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), true);
@@ -53,4 +53,6 @@ int main()
         static_assert( (it1 >= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
index a1b08f65c24..bc20d138137 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opindex/difference_type.pass.cpp
@@ -30,7 +30,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n,
     assert(rr == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 4, '1');
@@ -45,4 +45,6 @@ int main()
     static_assert(it1[4] == '1', "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
index 7e4f27e7a7c..e49821f833c 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 < r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
@@ -53,4 +53,6 @@ int main()
         static_assert(!(it1 < it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
index 8934d68efc5..92752361152 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.oplt=/test.pass.cpp
@@ -32,7 +32,7 @@ test(It l, It r, bool x)
     assert((r1 <= r2) == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), true);
@@ -53,4 +53,6 @@ int main()
         static_assert(!(it1 <= it3), "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
index ce0b470a612..f16fb2757a5 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opref/op_arrow.pass.cpp
@@ -76,7 +76,7 @@ public:
 
 TEST_CONSTEXPR  C gC;
 
-int main()
+int main(int, char**)
 {
     A a;
     test(&a+1, A());
@@ -115,4 +115,6 @@ int main()
     {
         ((void)gC);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
index 25876d07267..ba38448515d 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.ops/reverse.iter.opsum/difference_type.pass.cpp
@@ -31,7 +31,7 @@ test(It i, typename std::iterator_traits<It>::difference_type n, It x)
     assert(rr.base() == x);
 }
 
-int main()
+int main(int, char**)
 {
     const char* s = "1234567890";
     test(random_access_iterator<const char*>(s+5), 5, random_access_iterator<const char*>(s));
@@ -49,4 +49,6 @@ int main()
         static_assert(it2 != it3, "");
     }
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iter.requirements/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
index 7242f6a347c..11ac625258c 100644
--- a/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/predef.iterators/reverse.iterators/reverse.iterator/types.pass.cpp
@@ -52,9 +52,11 @@ test()
     static_assert((std::is_same<typename R::iterator_category, typename T::iterator_category>::value), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<bidirectional_iterator<char*> >();
     test<random_access_iterator<char*> >();
     test<char*>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
index 4ee68b5fc7a..d6a3b086287 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/copy.pass.cpp
@@ -20,7 +20,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         std::istream_iterator<int> io;
@@ -36,4 +36,6 @@ int main()
         j = *i;
         assert(j == 1);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
index 1ffe4dcfe3c..e2bebbaea10 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.fail.cpp
@@ -19,7 +19,7 @@
 
 struct S { S(); }; // not constexpr
 
-int main()
+int main(int, char**)
 {
 #if TEST_STD_VER >= 11
     {
@@ -28,4 +28,6 @@ int main()
 #else
 #error "C++11 only test"
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
index f569d3206d8..fa43566ddde 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp
@@ -42,7 +42,7 @@ void operator ()() const {}
 #endif
 
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::istream_iterator<int> T;
@@ -61,4 +61,6 @@ int main()
     test_trivial<S>()();
     test_trivial<std::string>()();
 #endif
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
index 50b40aba48c..a4c47974dae 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/istream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -26,4 +26,6 @@ int main()
     int j = 0;
     inf >> j;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
index a2862b4031f..5409cc5955b 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/arrow.pass.cpp
@@ -29,10 +29,12 @@ std::istream& operator>>(std::istream& is, A& a)
     return is >> a.d_ >> a.i_;
 }
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf("1.5  23 ");
     std::istream_iterator<A> i(inf);
     assert(i->d_ == 1.5);
     assert(i->i_ == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
index 38ffe4bfd7d..c99e723b041 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/dereference.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -30,4 +30,6 @@ int main()
     assert(j == 23);
     j = *i;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
index 5ba335c5edf..616a3ca3852 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/equal.pass.cpp
@@ -22,7 +22,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf1(" 1 23");
     std::istringstream inf2(" 1 23");
@@ -51,4 +51,6 @@ int main()
 
     assert(std::operator==(i1, i2));
     assert(std::operator!=(i1, i3));
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
index b32f358cf24..83d206e719b 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/post_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -28,4 +28,6 @@ int main()
     j = 0;
     j = *icopy;
     assert(j == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
index 6a361ff7172..ab61f57f9dc 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.ops/pre_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::istringstream inf(" 1 23");
     std::istream_iterator<int> i(inf);
@@ -25,4 +25,6 @@ int main()
     int j = 0;
     j = *i;
     assert(j == 23);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
index 9a7185c1b89..5170b1e5365 100644
--- a/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istream.iterator/types.pass.cpp
@@ -41,7 +41,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::istream_iterator<double> I1; // double is trivially destructible
 #if TEST_STD_VER <= 14
@@ -82,4 +82,6 @@ int main()
     typedef std::istream_iterator<std::string> I3; // string is NOT trivially destructible
     static_assert(!std::is_trivially_copy_constructible<I3>::value, "");
     static_assert(!std::is_trivially_destructible<I3>::value, "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
index d7e1a31e571..9502e0da7b9 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/default.pass.cpp
@@ -21,7 +21,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     {
         typedef std::istreambuf_iterator<char> T;
@@ -41,4 +41,6 @@ int main()
         (void)it2;
 #endif
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
index a7927cbb2f0..b51d19a8e5e 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/istream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf;
@@ -38,4 +38,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf);
         assert(i != std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
index 6b4719cadb0..87afe840d03 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/proxy.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -32,4 +32,6 @@ int main()
         assert(i != std::istreambuf_iterator<wchar_t>());
         assert(*i == L'b');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
index 2b94d8c9756..d92cddde1f1 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator.cons/streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istreambuf_iterator<char> i(nullptr);
@@ -46,4 +46,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf.rdbuf());
         assert(i != std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
index 9b003413161..1fcdf7af146 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_equal/equal.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -96,4 +96,6 @@ int main()
         assert( i5.equal(i4));
         assert( i5.equal(i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
index 7e50c68f7c1..d4184aa6ce6 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op!=/not_equal.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -98,4 +98,6 @@ int main()
         assert(!(i5 != i4));
         assert(!(i5 != i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
index 28cb7a93a4a..d60302ad40d 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op++/dereference.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -36,4 +36,6 @@ int main()
         ++i;
         assert(*i == L'c');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
index ede97380bb8..875989f5df5 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op==/equal.pass.cpp
@@ -18,7 +18,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf1("abc");
@@ -98,4 +98,6 @@ int main()
         assert( (i5 == i4));
         assert( (i5 == i5));
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
index 15c266d7314..e3121494df4 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/post_increment.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -34,4 +34,6 @@ int main()
         assert(*i++ == L'c');
         assert(i == std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
index 148bd725a7f..9d05cbda340 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_op_astrk/pre_increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -35,4 +35,6 @@ int main()
         assert(*++i == L'c');
         assert(++i == std::istreambuf_iterator<wchar_t>());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
index 2535d991397..74e1813d512 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/istreambuf.iterator_proxy/proxy.pass.cpp
@@ -28,7 +28,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::istringstream inf("abc");
@@ -40,4 +40,6 @@ int main()
         std::istreambuf_iterator<wchar_t> i(inf);
         assert(*i++ == L'a');
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
index 829d1f0a6df..a6c6435f10a 100644
--- a/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/istreambuf.iterator/types.pass.cpp
@@ -34,7 +34,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::istreambuf_iterator<char> I1;
     static_assert((std::is_same<I1::iterator_category, std::input_iterator_tag>::value), "");
@@ -65,4 +65,6 @@ int main()
     static_assert((std::is_nothrow_default_constructible<I2>::value), "" );
     static_assert((std::is_trivially_copy_constructible<I2>::value), "" );
     static_assert((std::is_trivially_destructible<I2>::value), "" );
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
index 3521b05fa8f..8d7500cf292 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_array.pass.cpp
@@ -13,11 +13,13 @@
 #include <iterator>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     int* i = std::begin(ia);
     assert(*i == 1);
     *i = 2;
     assert(ia[0] == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
index 255a837e734..06b5e7907e8 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     const std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::const_iterator i = begin(v);
     assert(*i == 1);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
index bc99f7a408c..75e61d3b411 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/begin_non_const.pass.cpp
@@ -13,7 +13,7 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
@@ -21,4 +21,6 @@ int main()
     assert(*i == 1);
     *i = 2;
     assert(*i == 2);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
index 0f21309baab..a6721155afd 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_array.pass.cpp
@@ -13,11 +13,13 @@
 #include <iterator>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     int* i = std::begin(ia);
     int* e = std::end(ia);
     assert(e == ia + 3);
     assert(e - i == 3);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
index 45796233202..78a6affd8a2 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     const std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::const_iterator i = end(v);
     assert(i == v.cend());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
index 8fa2a4e5600..9970ec922c3 100644
--- a/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/iterator.range/end_non_const.pass.cpp
@@ -13,10 +13,12 @@
 #include <vector>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     int ia[] = {1, 2, 3};
     std::vector<int> v(ia, ia + sizeof(ia)/sizeof(ia[0]));
     std::vector<int>::iterator i = end(v);
     assert(i == v.end());
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp b/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
index 24cf15ff1be..491f3bc1cec 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/copy.pass.cpp
@@ -16,11 +16,13 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream outf;
     std::ostream_iterator<int> i(outf);
     std::ostream_iterator<int> j = i;
     assert(outf.good());
     ((void)j);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
index 1de0ea2eabe..78abcfab677 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream.pass.cpp
@@ -23,7 +23,7 @@ typedef std::basic_ostream<char, MyTraits> BasicStream;
 
 void operator&(BasicStream const&) {}
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         std::ostream_iterator<int, char, MyTraits> i(outf);
         assert(outf.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
index 7b4422f94bd..2c48189f91a 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.cons.des/ostream_delim.pass.cpp
@@ -24,7 +24,7 @@ typedef std::basic_ostream<char, MyTraits> BasicStream;
 
 void operator&(BasicStream const&) {}
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -41,4 +41,6 @@ int main()
         std::ostream_iterator<int, char, MyTraits> i(outf, ", ");
         assert(outf.good());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
index dea585c3c04..5a2f2cc99f2 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/assign_t.pass.cpp
@@ -26,7 +26,7 @@
 #pragma warning(disable: 4244) // conversion from 'X' to 'Y', possible loss of data
 #endif
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -52,4 +52,6 @@ int main()
         i = 2.4;
         assert(outf.str() == L"2, ");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
index 4d79f7c1d56..6cb190ab491 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/dereference.pass.cpp
@@ -16,10 +16,12 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::ostream_iterator<int> i(os);
     std::ostream_iterator<int>& iref = *i;
     assert(&iref == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
index d93aad6cce5..eedab8115d8 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/ostream.iterator.ops/increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     std::ostringstream os;
     std::ostream_iterator<int> i(os);
@@ -25,4 +25,6 @@ int main()
     assert(&iref1 == &i);
     std::ostream_iterator<int>& iref2 = i++;
     assert(&iref2 == &i);
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
index 716ba2bfdc3..950c7dfe8c0 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostream.iterator/types.pass.cpp
@@ -24,7 +24,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::ostream_iterator<double> I1;
 #if TEST_STD_VER <= 14
@@ -54,4 +54,6 @@ int main()
     static_assert((std::is_same<I2::char_type, wchar_t>::value), "");
     static_assert((std::is_same<I2::traits_type, std::char_traits<wchar_t> >::value), "");
     static_assert((std::is_same<I2::ostream_type, std::wostream>::value), "");
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
index 0c28a77ac16..aa6031a8ad8 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/ostream.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -28,4 +28,6 @@ int main()
         std::ostreambuf_iterator<wchar_t> i(outf);
         assert(!i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
index 0d2c85bef84..2c64dc29fdb 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.cons/streambuf.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -28,4 +28,6 @@ int main()
         std::ostreambuf_iterator<wchar_t> i(outf.rdbuf());
         assert(!i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
index 45e57fc8007..fe51fba1fd5 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/assign_c.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         i = L'b';
         assert(outf.str() == L"ab");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
index e33a5a5c8f4..4904320b0a0 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/deref.pass.cpp
@@ -16,7 +16,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -30,4 +30,6 @@ int main()
         std::ostreambuf_iterator<wchar_t>& iref = *i;
         assert(&iref == &i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
index b52fce81344..fa67513ad6e 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/failed.pass.cpp
@@ -25,7 +25,7 @@ struct my_streambuf : public std::basic_streambuf<Char,Traits> {
     int_type sputc(char_type) { return Traits::eof(); }
     };
 
-int main()
+int main(int, char**)
 {
     {
         my_streambuf<char> buf;
@@ -39,4 +39,6 @@ int main()
         i = L'a';
         assert(i.failed());
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
index c765a5c2daa..81ae55ae7a6 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/ostreambuf.iter.ops/increment.pass.cpp
@@ -17,7 +17,7 @@
 #include <sstream>
 #include <cassert>
 
-int main()
+int main(int, char**)
 {
     {
         std::ostringstream outf;
@@ -35,4 +35,6 @@ int main()
         std::ostreambuf_iterator<wchar_t>& iref2 = i++;
         assert(&iref2 == &i);
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
index 346d8b8496f..671a09bb7a3 100644
--- a/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
+++ b/libcxx/test/std/iterators/stream.iterators/ostreambuf.iterator/types.pass.cpp
@@ -25,7 +25,7 @@
 
 #include "test_macros.h"
 
-int main()
+int main(int, char**)
 {
     typedef std::ostreambuf_iterator<char> I1;
 #if TEST_STD_VER <= 14
@@ -58,4 +58,6 @@ int main()
     static_assert((std::is_same<I2::traits_type, std::char_traits<wchar_t> >::value), "");
     static_assert((std::is_same<I2::streambuf_type, std::wstreambuf>::value), "");
     static_assert((std::is_same<I2::ostream_type, std::wostream>::value), "");
+
+  return 0;
 }