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

20 files changed, 60 insertions, 20 deletions

diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
index d7f775eee6e..abf75631f86 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_add<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
index ae43ac9222b..c62f75a0d87 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_add.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_add<R1, R2>::type R;
     static_assert(R::num == 1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
index ea96434b855..387f6290368 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 2> R2;
     typedef std::ratio_divide<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
index 0b93e1a9cea..ce7f69473bc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_divide.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_divide<R1, R2>::type R;
     static_assert(R::num == 630992477165LL && R::den == 127339199162436LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
index b884f4e2cb8..ef59bb39e41 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<2, 1> R2;
     typedef std::ratio_multiply<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
index 876158994e7..e20f2344347 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_multiply.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -54,4 +54,6 @@ int main()
     typedef std::ratio_multiply<R1, R2>::type R;
     static_assert(R::num == 15519594064236LL && R::den == 5177331081415LL, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
index 95e9c823908..8b00462dc48 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.fail.cpp
@@ -10,9 +10,11 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     typedef std::ratio<-0x7FFFFFFFFFFFFFFFLL, 1> R1;
     typedef std::ratio<1, 1> R2;
     typedef std::ratio_subtract<R1, R2>::type R;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
index dbb9480475d..e3871f7a7cf 100644
--- a/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.arithmetic/ratio_subtract.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -72,4 +72,6 @@ int main()
     typedef std::ratio_subtract<R1, R2>::type R;
     static_assert(R::num == -1 && R::den == 1, "");
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
index 9f547cdea56..d0b1d5a17be 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
index ab6deac86d0..dfb0e8fe87e 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
index 79942fa6d0d..811706c58aa 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_greater_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
index a80112ca4b8..45ba7cbf16c 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -93,4 +93,6 @@ int main()
     typedef std::ratio<641981, 1339063> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
index c5dbdedc8f6..ebb8624a85f 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_less_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, false>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
index 68e6aba35d0..5000e73d3fc 100644
--- a/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.comparison/ratio_not_equal.pass.cpp
@@ -21,7 +21,7 @@ void test()
 #endif
 }
 
-int main()
+int main(int, char**)
 {
     {
     typedef std::ratio<1, 1> R1;
@@ -63,4 +63,6 @@ int main()
     typedef std::ratio<1, -0x7FFFFFFFFFFFFFFFLL> R2;
     test<R1, R2, true>();
     }
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
index bb3bb159bde..336d7d8e5b5 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio.pass.cpp
@@ -18,7 +18,7 @@ void test()
     static_assert((std::ratio<N, D>::den == eD), "");
 }
 
-int main()
+int main(int, char**)
 {
     test<1, 1, 1, 1>();
     test<1, 10, 1, 10>();
@@ -40,4 +40,6 @@ int main()
     test<-0x7FFFFFFFFFFFFFFFLL, 127, -72624976668147841LL, 1>();
     test<0x7FFFFFFFFFFFFFFFLL, -127, -72624976668147841LL, 1>();
     test<-0x7FFFFFFFFFFFFFFFLL, -127, 72624976668147841LL, 1>();
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
index 1c143f659cb..0841d858dc9 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio1.fail.cpp
@@ -11,7 +11,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
index bf56271fbbe..f8bebc8624d 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio2.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<0x8000000000000000ULL, 1>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
index 6e44427f841..78310c6a245 100644
--- a/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.ratio/ratio3.fail.cpp
@@ -12,7 +12,9 @@
 #include <ratio>
 #include <cstdint>
 
-int main()
+int main(int, char**)
 {
     const std::intmax_t t1 = std::ratio<1, 0x8000000000000000ULL>::num;
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
index f77636c8475..1f764da05d6 100644
--- a/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/ratio.si/nothing_to_do.pass.cpp
@@ -6,6 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-int main()
+int main(int, char**)
 {
+
+  return 0;
 }
diff --git a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
index 3f54f555a89..8e24ff9749d 100644
--- a/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
+++ b/libcxx/test/std/utilities/ratio/typedefs.pass.cpp
@@ -10,7 +10,7 @@
 
 #include <ratio>
 
-int main()
+int main(int, char**)
 {
     static_assert(std::atto::num == 1 && std::atto::den == 1000000000000000000ULL, "");
     static_assert(std::femto::num == 1 && std::femto::den == 1000000000000000ULL, "");
@@ -28,4 +28,6 @@ int main()
     static_assert(std::tera::num == 1000000000000ULL && std::tera::den == 1, "");
     static_assert(std::peta::num == 1000000000000000ULL && std::peta::den == 1, "");
     static_assert(std::exa::num == 1000000000000000000ULL && std::exa::den == 1, "");
+
+  return 0;
 }