[libc++abi] Fix forced_unwind tests failures on ARM/EHABI targets.

[vvereschaka]

Summary

Added __cxxabi_config.h includes to resolve _LIBCXXABI_ARM_EHABI and proper building the forces_unwindX.cpp tests for the ARM/EHABI targets.

[vvereschaka]

ref https://reviews.llvm.org/D95200

Here is one of the failed builds for armv7 target
http://lab.llvm.org:8011/#/builders/60/builds/1950

[MaskRay]

Why is #include <cxxabi.h> needed?

[vvereschaka]

You are right, we don't need it. I did a copy/paste from another test.
Updated diff without cxxabi.h.

[MaskRay]

The int main() {} change is unnecessary but I don't know the libc++ specific code style well.

You still need an owner's approval.

[ldionne]

In D96378#2554606, @MaskRay wrote:

The int main() {} change is unnecessary but I don't know the libc++ specific code style well.

You still need an owner's approval.

LGTM except the nitpick about how main() is declared. When testing under freestanding mode, main isn't considered special. It needs to be declared as int main(int, char**) so it mangles the right way and we can call it explicitly from the test harness. It's kind of nitpicky.

libcxxabi/test/forced_unwind1.pass.cpp

21

Can you use int main(int, char**)?

[vvereschaka]

libcxxabi/test/forced_unwind1.pass.cpp

21

yes, I'll update it accordingly. Should we do the same for main() of the original test? I can update it there either.

[vvereschaka]

Updated main() -> main(int, char**) for the tests.

[vvereschaka]

@ldionne would you take a look at the updated diff?

[ldionne]

Still LGTM, my comment was a nitpick. Thanks :-)

libcxxabi/test/forced_unwind1.pass.cpp

 // rethrown. If not rethrown, exception_cleanup will be called.
 
 // UNSUPPORTED: no-exceptions, c++03
 
 #include <stdlib.h>
 #include <string.h>
 #include <unwind.h>
 #include <tuple>
+#include <__cxxabi_config.h>
 
 #if defined(_LIBCXXABI_ARM_EHABI)
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #else
 static int bits = 0;
 
 struct C {
   int bit;
   C(int b) : bit(b) {}
   ~C() { bits |= bit; }
 };
try {
       throw;
     }
   } catch (int) {
   } catch (...) {
     // __cxa_end_catch calls cleanup.
   }
 }
 
-int main() {
+int main(int, char**) {
   test();
   return bits != 15;
 }
 #endif

libcxxabi/test/forced_unwind2.pass.cpp

 // UNSUPPORTED: no-exceptions, c++03
 
 #include <exception>
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #include <unwind.h>
 #include <tuple>
+#include <__cxxabi_config.h>
 
 #if defined(_LIBCXXABI_ARM_EHABI)
-int main() {}
+int main(int, char**) {
+  return 0;
+}
 #else
 template <typename T>
 struct Stop;
 
 template <typename R, typename... Args>
 struct Stop<R (*)(Args...)> {
   // The third argument of _Unwind_Stop_Fn is uint64_t in Itanium C++ ABI/LLVM
   // libunwind while _Unwind_Exception_Class in libgcc.
static void forced_unwind() {
   _Unwind_ForcedUnwind(exc, Stop<_Unwind_Stop_Fn>::stop, 0);
   abort();
 }
 
 static void test() noexcept { forced_unwind(); }
 
 static void terminate() { exit(0); }
 
-int main() {
+int main(int, char**) {
   std::set_terminate(terminate);
   try {
     test();
   } catch (...) {
   }
   abort();
 }
 #endif