[CMake] Check -ffreestanding as C not C++ flag

When -ffreestanding is used, main() isn't considered special and
when compiled as C++ code it'll get mangled which makes the
compilation fail since main() will be undefined so this check will
never succeed.

Differential Revision: https://reviews.llvm.org/D49332

llvm-svn: 345632

diff --git a/compiler-rt/cmake/config-ix.cmake b/compiler-rt/cmake/config-ix.cmake
index 27097b7..8ab9f1f 100644 (file)
--- a/compiler-rt/cmake/config-ix.cmake
+++ b/compiler-rt/cmake/config-ix.cmake
@@ -53,6 +53,7 @@ if (COMPILER_RT_HAS_NODEFAULTLIBS_FLAG)
 endif ()
 
 # CodeGen options.
+check_c_compiler_flag(-ffreestanding         COMPILER_RT_HAS_FFREESTANDING_FLAG)
 check_cxx_compiler_flag(-fPIC                COMPILER_RT_HAS_FPIC_FLAG)
 check_cxx_compiler_flag(-fPIE                COMPILER_RT_HAS_FPIE_FLAG)
 check_cxx_compiler_flag(-fno-builtin         COMPILER_RT_HAS_FNO_BUILTIN_FLAG)
@@ -64,7 +65,6 @@ check_cxx_compiler_flag(-fno-sanitize=safe-stack COMPILER_RT_HAS_FNO_SANITIZE_SA
 check_cxx_compiler_flag(-fvisibility=hidden  COMPILER_RT_HAS_FVISIBILITY_HIDDEN_FLAG)
 check_cxx_compiler_flag(-frtti               COMPILER_RT_HAS_FRTTI_FLAG)
 check_cxx_compiler_flag(-fno-rtti            COMPILER_RT_HAS_FNO_RTTI_FLAG)
-check_cxx_compiler_flag(-ffreestanding       COMPILER_RT_HAS_FFREESTANDING_FLAG)
 check_cxx_compiler_flag("-Werror -fno-function-sections" COMPILER_RT_HAS_FNO_FUNCTION_SECTIONS_FLAG)
 check_cxx_compiler_flag(-std=c++11           COMPILER_RT_HAS_STD_CXX11_FLAG)
 check_cxx_compiler_flag(-ftls-model=initial-exec COMPILER_RT_HAS_FTLS_MODEL_INITIAL_EXEC)