Add -funwind-tables to CMAKE_C_FLAGS.

[logan]

Summary

Without -funwind-tables, the compiler won't generate the unwinding
table for these C functions. However, the functions in libunwind,
such as _Unwind_Backtrace(), WILL unwind stack to get the backtrace.

[rengolin]

I'm not a CMake expert, but I think this is ok. I suppose you have tested with Clang and GCC.

[danalbert]

cmake/config-ix.cmake

7

Shouldn't this be check_c_compiler_flag?

[logan]

Address the review comments from Dan Albert.

cmake/config-ix.cmake

7

Done.

[jroelofs]

LGTM

[logan]

@rengolin I have tried to compile with arm-linux-gnueabihf-g++-4.7 but it doesn't compile libcxxabi. After applying some hacks, I found that 3 tests failed. However, they seem unrelated to this change (it looks like the code generation issue.)

[rengolin]

If the same error happens without the patch, than LGTM too. Thanks!

[logan]

Thanks. Committed as rL226823.

CMakeLists.txt

 
 # Get required flags.
 macro(append_if list condition var)
   if (${condition})
     list(APPEND ${list} ${var})
   endif()
 endmacro()
 
+set(LIBCXXABI_C_FLAGS "")
 set(LIBCXXABI_CXX_FLAGS "")
 set(LIBCXXABI_COMPILE_FLAGS "")
 set(LIBCXXABI_LINK_FLAGS "")
 
 
 if (LIBCXXABI_HAS_NOSTDINCXX_FLAG)
   list(APPEND LIBCXXABI_COMPILE_FLAGS -nostdinc++)
   # Remove -stdlib flags to prevent them from causing an unused flag warning.

 
 # Get feature flags.
 # Exceptions
 # Catches C++ exceptions only and tells the compiler to assume that extern C
 # functions never throw a C++ exception.
 append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_FSTRICT_ALIASING_FLAG -fstrict-aliasing)
 append_if(LIBCXXABI_CXX_FLAGS LIBCXXABI_HAS_EHSC_FLAG -EHsc)
 
+append_if(LIBCXXABI_C_FLAGS LIBCXXABI_HAS_FUNWIND_TABLES -funwind-tables)
+
 # Assert
 string(TOUPPER "${CMAKE_BUILD_TYPE}" uppercase_CMAKE_BUILD_TYPE)
 if (LIBCXXABI_ENABLE_ASSERTIONS)
   # MSVC doesn't like _DEBUG on release builds. See PR 4379.
   if (NOT MSVC)
     list(APPEND LIBCXXABI_COMPILE_FLAGS -D_DEBUG)
   endif()
   # On Release builds cmake automatically defines NDEBUG, so we

 append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_TARGET_TRIPLE
           "-target ${LIBCXXABI_TARGET_TRIPLE}")
 append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_GCC_TOOLCHAIN
          "-gcc-toolchain ${LIBCXXABI_GCC_TOOLCHAIN}")
 append_if(LIBCXXABI_COMPILE_FLAGS LIBCXXABI_SYSROOT
           "--sysroot ${LIBCXXABI_SYSROOT}")
 string(REPLACE ";" " " LIBCXXABI_CXX_FLAGS "${LIBCXXABI_CXX_FLAGS}")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${LIBCXXABI_CXX_FLAGS}")
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${LIBCXXABI_C_FLAGS}")
 
 #===============================================================================
 # Setup Source Code
 #===============================================================================
 
 include_directories(include)
 
 # Add source code. This also contains all of the logic for deciding linker flags

cmake/config-ix.cmake

 include(CheckLibraryExists)
 include(CheckCXXCompilerFlag)
 
 # Check compiler flags
 check_cxx_compiler_flag(-fPIC                 LIBCXXABI_HAS_FPIC_FLAG)
 check_cxx_compiler_flag(-fstrict-aliasing     LIBCXXABI_HAS_FSTRICT_ALIASING_FLAG)
+check_cxx_compiler_flag(-funwind-tables       LIBCXXABI_HAS_FUNWIND_TABLES)
 check_cxx_compiler_flag(-nodefaultlibs        LIBCXXABI_HAS_NODEFAULTLIBS_FLAG)
 check_cxx_compiler_flag(-nostdinc++           LIBCXXABI_HAS_NOSTDINCXX_FLAG)
 check_cxx_compiler_flag(-Wall                 LIBCXXABI_HAS_WALL_FLAG)
 check_cxx_compiler_flag(-W                    LIBCXXABI_HAS_W_FLAG)
 check_cxx_compiler_flag(-Wno-unused-function  LIBCXXABI_HAS_WNO_UNUSED_FUNCTION_FLAG)
 check_cxx_compiler_flag(-Wunused-variable     LIBCXXABI_HAS_WUNUSED_VARIABLE_FLAG)
 check_cxx_compiler_flag(-Wunused-parameter    LIBCXXABI_HAS_WUNUSED_PARAMETER_FLAG)
 check_cxx_compiler_flag(-Wstrict-aliasing     LIBCXXABI_HAS_WSTRICT_ALIASING_FLAG)