Author: phosek Date: Sun Jan 27 20:12:54 2019 New Revision: 352341 URL: http://llvm.org/viewvc/llvm-project?rev=352341&view=rev Log: [CMake] Use __libc_start_main rather than fopen when checking for C library
The check_library_exists CMake uses a custom symbol definition. This is a problem when checking for C library symbols because Clang recognizes many of them as builtins, and returns the -Wbuiltin-requires-header (or -Wincompatible-library-redeclaration) error. When building with -Werror which is the default, this causes the check_library_exists check fail making the build think that C library isn't available. To avoid this issue, we should use a symbol that isn't recognized by Clang and wouldn't cause the same issue. __libc_start_main seems like reasonable choice that fits the bill. Differential Revision: https://reviews.llvm.org/D57142 Modified: libunwind/trunk/cmake/config-ix.cmake Modified: libunwind/trunk/cmake/config-ix.cmake URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/cmake/config-ix.cmake?rev=352341&r1=352340&r2=352341&view=diff ============================================================================== --- libunwind/trunk/cmake/config-ix.cmake (original) +++ libunwind/trunk/cmake/config-ix.cmake Sun Jan 27 20:12:54 2019 @@ -3,7 +3,7 @@ include(CheckCCompilerFlag) include(CheckCXXCompilerFlag) include(CheckLibraryExists) -check_library_exists(c fopen "" LIBUNWIND_HAS_C_LIB) +check_library_exists(c __libc_start_main "" LIBUNWIND_HAS_C_LIB) if (NOT LIBUNWIND_USE_COMPILER_RT) check_library_exists(gcc_s __gcc_personality_v0 "" LIBUNWIND_HAS_GCC_S_LIB) _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
