[CMake] Rename back SIMPLE_SOURCE to compile as C++

This was changed in rL276151 and causes problems if the C++ compiler does not
support the same arches as the C compiler.
For the builtins, only the C compiler is tested in try_compile_only.

Additionally, -fno-exceptions is passed in (if available) to work around
the case where no libunwind is available.

Differential Revision: https://reviews.llvm.org/D23654

llvm-svn: 282054

compiler-rt/cmake/Modules/CompilerRTUtils.cmake

@@ -132,8 +132,12 @@ macro(test_target_arch arch def)
       try_compile_only(CAN_TARGET_${arch} ${TARGET_${arch}_CFLAGS})
     else()
       set(argstring "${CMAKE_EXE_LINKER_FLAGS} ${argstring}")
+      set(FLAG_NO_EXCEPTIONS "")
+      if(COMPILER_RT_HAS_FNO_EXCEPTIONS_FLAG)
+        set(FLAG_NO_EXCEPTIONS " -fno-exceptions ")
+      endif()
       try_compile(CAN_TARGET_${arch} ${CMAKE_BINARY_DIR} ${SIMPLE_SOURCE}
-                  COMPILE_DEFINITIONS "${TARGET_${arch}_CFLAGS}"
+                  COMPILE_DEFINITIONS "${TARGET_${arch}_CFLAGS} ${FLAG_NO_EXCEPTIONS}"
                   OUTPUT_VARIABLE TARGET_${arch}_OUTPUT
                   CMAKE_FLAGS "-DCMAKE_EXE_LINKER_FLAGS:STRING=${argstring}")
     endif()

compiler-rt/cmake/config-ix.cmake

@@ -92,7 +92,7 @@ set(COMPILER_RT_SUPPORTED_ARCH)
 # platform. We use the results of these tests to build only the various target
 # runtime libraries supported by our current compilers cross-compiling
 # abilities.
-set(SIMPLE_SOURCE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/simple.c)
+set(SIMPLE_SOURCE ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/simple.cc)
 file(WRITE ${SIMPLE_SOURCE} "#include <stdlib.h>\n#include <stdio.h>\nint main() { printf(\"hello, world\"); }\n")
 
 # Add $arch as supported with no additional flags.