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# - Adds a compiler flag if it is supported by the compiler
#
# This function checks that the supplied compiler flag is supported and then
# adds it to the corresponding compiler flags
#
# add_cxx_compiler_flag(<FLAG> [<VARIANT>])
#
# - Example
#
# include(AddCXXCompilerFlag)
# add_cxx_compiler_flag(-Wall)
# add_cxx_compiler_flag(-no-strict-aliasing RELEASE)
# Requires CMake 2.6+
if(__add_cxx_compiler_flag)
return()
endif()
set(__add_cxx_compiler_flag INCLUDED)
include(CheckCXXCompilerFlag)
function(mangle_compiler_flag FLAG OUTPUT)
string(TOUPPER "HAVE_CXX_FLAG_${FLAG}" SANITIZED_FLAG)
string(REPLACE "+" "X" SANITIZED_FLAG ${SANITIZED_FLAG})
string(REGEX REPLACE "[^A-Za-z_0-9]" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
string(REGEX REPLACE "_+" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
set(${OUTPUT} "${SANITIZED_FLAG}" PARENT_SCOPE)
endfunction(mangle_compiler_flag)
function(add_cxx_compiler_flag FLAG)
mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
if(${MANGLED_FLAG})
set(VARIANT ${ARGV1})
if(ARGV1)
string(TOUPPER "_${VARIANT}" VARIANT)
endif()
set(CMAKE_CXX_FLAGS${VARIANT} "${CMAKE_CXX_FLAGS${VARIANT}} ${BENCHMARK_CXX_FLAGS${VARIANT}} ${FLAG}" PARENT_SCOPE)
endif()
endfunction()
function(add_required_cxx_compiler_flag FLAG)
mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
if(${MANGLED_FLAG})
set(VARIANT ${ARGV1})
if(ARGV1)
string(TOUPPER "_${VARIANT}" VARIANT)
endif()
set(CMAKE_CXX_FLAGS${VARIANT} "${CMAKE_CXX_FLAGS${VARIANT}} ${FLAG}" PARENT_SCOPE)
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}" PARENT_SCOPE)
else()
message(FATAL_ERROR "Required flag '${FLAG}' is not supported by the compiler")
endif()
endfunction()
function(check_cxx_warning_flag FLAG)
mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
# Add -Werror to ensure the compiler generates an error if the warning flag
# doesn't exist.
set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror ${FLAG}")
check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
endfunction()