Do not predefine __EXCEPTIONS in clang-cl

[• ehsan]

Summary

This makes clang-cl able to build code which uses the gcc-defined __EXCEPTIONS macro for detecting whether -fno-exceptions has been passed to clang. cl.exe does not provide a similar way of disabling C++ exceptions, and never prefedines this variable.

[hans]

This looks good to me. As long as we don't have exceptions support, we shouldn't define this macro.

[rnk]

test/Frontend/exceptions.c

1

I think '-x cl' says this file is OpenCL code. The test line should probably be:

// RUN: %clang_cc1 -verify -fms-compatibility -fcxx-exceptions -fexceptions %s

[hans]

test/Frontend/exceptions.c

1

Sorry, I should have caught that when reviewing.

I did notice it when preparing to land Ehsan's patch though, so fixing it now.

[hans]

Closed by commit rL210582 (authored by @hans).

lib/Frontend/InitPreprocessor.cpp

     Builder.defineMacro("__BLOCKS__");
   }
 
-  if (LangOpts.CXXExceptions)
+  if (!LangOpts.MSVCCompat && LangOpts.CXXExceptions)
     Builder.defineMacro("__EXCEPTIONS");
   if (LangOpts.RTTI)
     Builder.defineMacro("__GXX_RTTI");

test/Frontend/exceptions.c

+// RUN: %clang_cc1 -x cl %s
+// expected-no-diagnostics
+
+#if defined(__EXCEPTIONS)
+#error __EXCEPTIONS should not be defined.
+#endif