Do not define GXX_RTTI macro for C

[ygao]

Summary

Hi,
I was looking at the list of pre-defined macros by the new LLVM release and noticed that the __GXX_RTTI macro is being defined for both C and C++, and I wonder maybe it makes sense to only enable RTTI for C++. What do you think?
Thanks in advance,

• Gao

[ygao]

A gentle ping.

[rsmith]

LGTM, assuming this is the same behaviour as GCC.

cfe/trunk/lib/Frontend/CompilerInvocation.cpp

#include "clang/Frontend/LangStandards.def"
   if (Args.hasArg(OPT_fno_threadsafe_statics))
     Opts.ThreadsafeStatics = 0;
   Opts.Exceptions = Args.hasArg(OPT_fexceptions);
   Opts.ObjCExceptions = Args.hasArg(OPT_fobjc_exceptions);
   Opts.CXXExceptions = Args.hasArg(OPT_fcxx_exceptions);
   Opts.SjLjExceptions = Args.hasArg(OPT_fsjlj_exceptions);
   Opts.TraditionalCPP = Args.hasArg(OPT_traditional_cpp);
 
-  Opts.RTTI = !Args.hasArg(OPT_fno_rtti);
+  Opts.RTTI = Opts.CPlusPlus && !Args.hasArg(OPT_fno_rtti);
   Opts.RTTIData = Opts.RTTI && !Args.hasArg(OPT_fno_rtti_data);
   Opts.Blocks = Args.hasArg(OPT_fblocks);
   Opts.BlocksRuntimeOptional = Args.hasArg(OPT_fblocks_runtime_optional);
   Opts.Coroutines = Args.hasArg(OPT_fcoroutines);
   Opts.Modules = Args.hasArg(OPT_fmodules);
   Opts.ModulesStrictDeclUse = Args.hasArg(OPT_fmodules_strict_decluse);
   Opts.ModulesDeclUse =
       Args.hasArg(OPT_fmodules_decluse) || Opts.ModulesStrictDeclUse;

cfe/trunk/test/Preprocessor/init.c

 //
 // DEPRECATED:#define __DEPRECATED 1
 //
 // 
 // RUN: %clang_cc1 -std=c99 -E -dM < /dev/null | FileCheck -check-prefix C99 %s
 //
 // C99:#define __STDC_VERSION__ 199901L
 // C99:#define __STRICT_ANSI__ 1
+// C99-NOT: __GXX_EXPERIMENTAL_CXX0X__
+// C99-NOT: __GXX_RTTI
+// C99-NOT: __GXX_WEAK__
+// C99-NOT: __cplusplus
 //
 // 
 // RUN: %clang_cc1 -std=c11 -E -dM < /dev/null | FileCheck -check-prefix C11 %s
 //
 // C11:#define __STDC_UTF_16__ 1
 // C11:#define __STDC_UTF_32__ 1
 // C11:#define __STDC_VERSION__ 201112L
 // C11:#define __STRICT_ANSI__ 1
+// C11-NOT: __GXX_EXPERIMENTAL_CXX0X__
+// C11-NOT: __GXX_RTTI
+// C11-NOT: __GXX_WEAK__
+// C11-NOT: __cplusplus
 //
 // 
 // RUN: %clang_cc1 -E -dM < /dev/null | FileCheck -check-prefix COMMON %s
 //
 // COMMON:#define __CONSTANT_CFSTRINGS__ 1
 // COMMON:#define __FINITE_MATH_ONLY__ 0
 // COMMON:#define __GNUC_MINOR__
 // COMMON:#define __GNUC_PATCHLEVEL__

 // MIPSN32BE: #define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // MIPSN32BE: #define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // MIPSN32BE: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
 // MIPSN32BE: #define __GNUC_MINOR__ 2
 // MIPSN32BE: #define __GNUC_PATCHLEVEL__ 1
 // MIPSN32BE: #define __GNUC_STDC_INLINE__ 1
 // MIPSN32BE: #define __GNUC__ 4
 // MIPSN32BE: #define __GXX_ABI_VERSION 1002
-// MIPSN32BE: #define __GXX_RTTI 1
 // MIPSN32BE: #define __ILP32__ 1
 // MIPSN32BE: #define __INT16_C_SUFFIX__
 // MIPSN32BE: #define __INT16_FMTd__ "hd"
 // MIPSN32BE: #define __INT16_FMTi__ "hi"
 // MIPSN32BE: #define __INT16_MAX__ 32767
 // MIPSN32BE: #define __INT16_TYPE__ short
 // MIPSN32BE: #define __INT32_C_SUFFIX__
 // MIPSN32BE: #define __INT32_FMTd__ "d"

 // MIPSN32EL: #define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // MIPSN32EL: #define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // MIPSN32EL: #define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
 // MIPSN32EL: #define __GNUC_MINOR__ 2
 // MIPSN32EL: #define __GNUC_PATCHLEVEL__ 1
 // MIPSN32EL: #define __GNUC_STDC_INLINE__ 1
 // MIPSN32EL: #define __GNUC__ 4
 // MIPSN32EL: #define __GXX_ABI_VERSION 1002
-// MIPSN32EL: #define __GXX_RTTI 1
 // MIPSN32EL: #define __ILP32__ 1
 // MIPSN32EL: #define __INT16_C_SUFFIX__
 // MIPSN32EL: #define __INT16_FMTd__ "hd"
 // MIPSN32EL: #define __INT16_FMTi__ "hi"
 // MIPSN32EL: #define __INT16_MAX__ 32767
 // MIPSN32EL: #define __INT16_TYPE__ short
 // MIPSN32EL: #define __INT32_C_SUFFIX__
 // MIPSN32EL: #define __INT32_FMTd__ "d"

 // X86_64-CLOUDABI:#define __GCC_ATOMIC_SHORT_LOCK_FREE 2
 // X86_64-CLOUDABI:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1
 // X86_64-CLOUDABI:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2
 // X86_64-CLOUDABI:#define __GNUC_MINOR__ 2
 // X86_64-CLOUDABI:#define __GNUC_PATCHLEVEL__ 1
 // X86_64-CLOUDABI:#define __GNUC_STDC_INLINE__ 1
 // X86_64-CLOUDABI:#define __GNUC__ 4
 // X86_64-CLOUDABI:#define __GXX_ABI_VERSION 1002
-// X86_64-CLOUDABI:#define __GXX_RTTI 1
 // X86_64-CLOUDABI:#define __INT16_C_SUFFIX__ 
 // X86_64-CLOUDABI:#define __INT16_FMTd__ "hd"
 // X86_64-CLOUDABI:#define __INT16_FMTi__ "hi"
 // X86_64-CLOUDABI:#define __INT16_MAX__ 32767
 // X86_64-CLOUDABI:#define __INT16_TYPE__ short
 // X86_64-CLOUDABI:#define __INT32_C_SUFFIX__ 
 // X86_64-CLOUDABI:#define __INT32_FMTd__ "d"
 // X86_64-CLOUDABI:#define __INT32_FMTi__ "i"

 // WEBASSEMBLY32-NEXT:#define __GCC_ATOMIC_SHORT_LOCK_FREE 2{{$}}
 // WEBASSEMBLY32-NEXT:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1{{$}}
 // WEBASSEMBLY32-NEXT:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2{{$}}
 // WEBASSEMBLY32-NEXT:#define __GNUC_MINOR__ {{.}}
 // WEBASSEMBLY32-NEXT:#define __GNUC_PATCHLEVEL__ {{.}}
 // WEBASSEMBLY32-NEXT:#define __GNUC_STDC_INLINE__ 1{{$}}
 // WEBASSEMBLY32-NEXT:#define __GNUC__ {{.}}
 // WEBASSEMBLY32-NEXT:#define __GXX_ABI_VERSION 1002{{$}}
-// WEBASSEMBLY32-NEXT:#define __GXX_RTTI 1{{$}}
 // WEBASSEMBLY32-NEXT:#define __ILP32__ 1{{$}}
 // WEBASSEMBLY32-NEXT:#define __INT16_C_SUFFIX__ {{$}}
 // WEBASSEMBLY32-NEXT:#define __INT16_FMTd__ "hd"{{$}}
 // WEBASSEMBLY32-NEXT:#define __INT16_FMTi__ "hi"{{$}}
 // WEBASSEMBLY32-NEXT:#define __INT16_MAX__ 32767{{$}}
 // WEBASSEMBLY32-NEXT:#define __INT16_TYPE__ short{{$}}
 // WEBASSEMBLY32-NEXT:#define __INT32_C_SUFFIX__ {{$}}
 // WEBASSEMBLY32-NEXT:#define __INT32_FMTd__ "d"{{$}}

 // WEBASSEMBLY64-NEXT:#define __GCC_ATOMIC_SHORT_LOCK_FREE 2{{$}}
 // WEBASSEMBLY64-NEXT:#define __GCC_ATOMIC_TEST_AND_SET_TRUEVAL 1{{$}}
 // WEBASSEMBLY64-NEXT:#define __GCC_ATOMIC_WCHAR_T_LOCK_FREE 2{{$}}
 // WEBASSEMBLY64-NEXT:#define __GNUC_MINOR__ {{.}}
 // WEBASSEMBLY64-NEXT:#define __GNUC_PATCHLEVEL__ {{.}}
 // WEBASSEMBLY64-NEXT:#define __GNUC_STDC_INLINE__ 1{{$}}
 // WEBASSEMBLY64-NEXT:#define __GNUC__ {{.}}
 // WEBASSEMBLY64-NEXT:#define __GXX_ABI_VERSION 1002{{$}}
-// WEBASSEMBLY64-NEXT:#define __GXX_RTTI 1{{$}}
 // WEBASSEMBLY64-NOT:#define __ILP32__
 // WEBASSEMBLY64-NEXT:#define __INT16_C_SUFFIX__ {{$}}
 // WEBASSEMBLY64-NEXT:#define __INT16_FMTd__ "hd"{{$}}
 // WEBASSEMBLY64-NEXT:#define __INT16_FMTi__ "hi"{{$}}
 // WEBASSEMBLY64-NEXT:#define __INT16_MAX__ 32767{{$}}
 // WEBASSEMBLY64-NEXT:#define __INT16_TYPE__ short{{$}}
 // WEBASSEMBLY64-NEXT:#define __INT32_C_SUFFIX__ {{$}}
 // WEBASSEMBLY64-NEXT:#define __INT32_FMTd__ "d"{{$}}