[PATCH] D12036: We shouldn't need to pass -fno-strict-aliasing when building clang with clang.

[Justin Bogner via cfe-commits]

Chris Bieneman <beanz at apple.com> writes:
> beanz updated this revision to Diff 32349.
> beanz added a comment.
>
> - Adapting to r245255 which exposes a variable in autoconf for which
> compiler you are building with.
> - Updated the CMake to be more CMake-y
>
> Note: This has been tested by running a check on a stage2 clang built
> with asan and ubsan.

LGTM.

>
> http://reviews.llvm.org/D12036
>
> Files:
>   CMakeLists.txt
>   Makefile
>
> Index: Makefile
> ===================================================================
> --- Makefile
> +++ Makefile
> @@ -67,8 +67,11 @@
>  #   http://gcc.gnu.org/PR41874
>  #   http://gcc.gnu.org/PR41838
>  #
> -# We can revisit this when LLVM/Clang support it.
> +# We don't need to do this if the host compiler is clang.
> +ifeq ($(CXX_COMPILER), "clang")
>  CXX.Flags += -fno-strict-aliasing
> +endif
> +
>  
>  # Set up Clang's tblgen.
>  ifndef CLANG_TBLGEN
> Index: CMakeLists.txt
> ===================================================================
> --- CMakeLists.txt
> +++ CMakeLists.txt
> @@ -253,7 +253,10 @@
>  
>  # Add appropriate flags for GCC
>  if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
> -  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual -fno-strict-aliasing")
> +  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual")
> +  if (NOT "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
> +    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-strict-aliasing")
> +  endif ()
>  
>    # Enable -pedantic for Clang even if it's not enabled for LLVM.
>    if (NOT LLVM_ENABLE_PEDANTIC)
>
>
> Index: Makefile
> ===================================================================
> --- Makefile
> +++ Makefile
> @@ -67,8 +67,11 @@
>  #   http://gcc.gnu.org/PR41874
>  #   http://gcc.gnu.org/PR41838
>  #
> -# We can revisit this when LLVM/Clang support it.
> +# We don't need to do this if the host compiler is clang.
> +ifeq ($(CXX_COMPILER), "clang")
>  CXX.Flags += -fno-strict-aliasing
> +endif
> +
>  
>  # Set up Clang's tblgen.
>  ifndef CLANG_TBLGEN
> Index: CMakeLists.txt
> ===================================================================
> --- CMakeLists.txt
> +++ CMakeLists.txt
> @@ -253,7 +253,10 @@
>  
>  # Add appropriate flags for GCC
>  if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
> -  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual -fno-strict-aliasing")
> +  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-common -Woverloaded-virtual")
> +  if (NOT "${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
> +    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-strict-aliasing")
> +  endif ()
>  
>    # Enable -pedantic for Clang even if it's not enabled for LLVM.
>    if (NOT LLVM_ENABLE_PEDANTIC)