From dda331284db4cb6a43481aa7735dee26e504ff36 Mon Sep 17 00:00:00 2001 From: Tom Stellard Date: Thu, 13 Dec 2018 18:21:23 +0000 Subject: [PATCH] Don't add unnecessary compiler flags to llvm-config output Summary: llvm-config --cxxflags --cflags, should only output the minimal flags required to link against the llvm libraries. They currently contain all flags used to compile llvm including flags like -g, -pedantic, -Wall, etc, which users may not always want. This changes the llvm-config output to only include flags that have been explictly added to the COMPILE_FLAGS property of the llvm-config target by the llvm build system. llvm.org/PR8220 Output from llvm-config when running cmake with: cmake -G Ninja .. -DCMAKE_CXX_FLAGS=-funroll-loops Before: --cppflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include -D_GNU_SOURCE -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS --cflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include -fPIC -Werror=date-time -Wall -Wextra -Wno-unused-parameter -Wwrite-strings \ -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough \ -Wno-comment -fdiagnostics-color -g -D_GNU_SOURCE -D_DEBUG -D__STDC_CONSTANT_MACROS \ -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS --cxxflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include\ -funroll-loops -fPIC -fvisibility-inlines-hidden -Werror=date-time -std=c++11 -Wall \ -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers \ -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized \ -Wno-class-memaccess -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment \ -fdiagnostics-color -g -fno-exceptions -fno-rtti -D_GNU_SOURCE -D_DEBUG \ -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS" After: --cppflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include \ -D_GNU_SOURCE -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS --cflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include \ -D_GNU_SOURCE -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS --cxxflags: -I$HEADERS_DIR/llvm/include -I$HEADERS_DIR/llvm/build/include \ -std=c++11 -fno-exceptions -fno-rtti \ -D_GNU_SOURCE -D_DEBUG -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS Reviewers: sylvestre.ledru, infinity0, mgorny Reviewed By: sylvestre.ledru, mgorny Subscribers: mgorny, dmgreen, llvm-commits Differential Revision: https://reviews.llvm.org/D55391 llvm-svn: 349068 --- llvm/tools/llvm-config/CMakeLists.txt | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/tools/llvm-config/CMakeLists.txt b/tools/llvm-config/CMakeLists.txt index a0bd36c3731..a7db17386fb 100644 --- a/tools/llvm-config/CMakeLists.txt +++ b/tools/llvm-config/CMakeLists.txt @@ -29,12 +29,20 @@ string(REPLACE ";" " " SYSTEM_LIBS "${SYSTEM_LIBS}") # Fetch target specific compile options, e.g. RTTI option get_property(COMPILE_FLAGS TARGET llvm-config PROPERTY COMPILE_FLAGS) +# The language standard potentially affects the ABI/API of LLVM, so we want +# to make sure it is reported by llvm-config. +# NOTE: We don't want to start extracting any random C/CXX flags that the +# user may add that could affect the ABI. We only want to extract flags +# that have been added by the LLVM build system. +string(REGEX MATCH "-std=[^ ]\+" LLVM_CXX_STD_FLAG ${CMAKE_CXX_FLAGS}) +string(REGEX MATCH "-std=[^ ]\+" LLVM_C_STD_FLAG ${CMAKE_C_FLAGS}) + # Use configure_file to create BuildVariables.inc. set(LLVM_SRC_ROOT ${LLVM_MAIN_SRC_DIR}) set(LLVM_OBJ_ROOT ${LLVM_BINARY_DIR}) -set(LLVM_CPPFLAGS "${CMAKE_CPP_FLAGS} ${CMAKE_CPP_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}") -set(LLVM_CFLAGS "${CMAKE_C_FLAGS} ${CMAKE_C_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${LLVM_DEFINITIONS}") -set(LLVM_CXXFLAGS "${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_${uppercase_CMAKE_BUILD_TYPE}} ${COMPILE_FLAGS} ${LLVM_DEFINITIONS}") +set(LLVM_CPPFLAGS "${LLVM_DEFINITIONS}") +set(LLVM_CFLAGS "${LLVM_C_STD_FLAG} ${LLVM_DEFINITIONS}") +set(LLVM_CXXFLAGS "${LLVM_CXX_STD_FLAG} ${COMPILE_FLAGS} ${LLVM_DEFINITIONS}") set(LLVM_BUILD_SYSTEM cmake) set(LLVM_HAS_RTTI ${LLVM_CONFIG_HAS_RTTI}) set(LLVM_DYLIB_VERSION "${LLVM_VERSION_MAJOR}${LLVM_VERSION_SUFFIX}")