utils/benchmark/cmake/AddCXXCompilerFlag.cmake

   1 # - Adds a compiler flag if it is supported by the compiler
   2 #
   3 # This function checks that the supplied compiler flag is supported and then
   4 # adds it to the corresponding compiler flags
   5 #
   6 #  add_cxx_compiler_flag(<FLAG> [<VARIANT>])
   7 #
   8 # - Example
   9 #
  10 # include(AddCXXCompilerFlag)
  11 # add_cxx_compiler_flag(-Wall)
  12 # add_cxx_compiler_flag(-no-strict-aliasing RELEASE)
  13 # Requires CMake 2.6+
  14
  15 if(__add_cxx_compiler_flag)
  16   return()
  17 endif()
  18 set(__add_cxx_compiler_flag INCLUDED)
  19
  20 include(CheckCXXCompilerFlag)
  21
  22 function(mangle_compiler_flag FLAG OUTPUT)
  23   string(TOUPPER "HAVE_CXX_FLAG_${FLAG}" SANITIZED_FLAG)
  24   string(REPLACE "+" "X" SANITIZED_FLAG ${SANITIZED_FLAG})
  25   string(REGEX REPLACE "[^A-Za-z_0-9]" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
  26   string(REGEX REPLACE "_+" "_" SANITIZED_FLAG ${SANITIZED_FLAG})
  27   set(${OUTPUT} "${SANITIZED_FLAG}" PARENT_SCOPE)
  28 endfunction(mangle_compiler_flag)
  29
  30 function(add_cxx_compiler_flag FLAG)
  31   mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
  32   set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
  33   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
  34   check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
  35   set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
  36   if(${MANGLED_FLAG})
  37     set(VARIANT ${ARGV1})
  38     if(ARGV1)
  39       string(TOUPPER "_${VARIANT}" VARIANT)
  40     endif()
  41     set(CMAKE_CXX_FLAGS${VARIANT} "${CMAKE_CXX_FLAGS${VARIANT}} ${BENCHMARK_CXX_FLAGS${VARIANT}} ${FLAG}" PARENT_SCOPE)
  42   endif()
  43 endfunction()
  44
  45 function(add_required_cxx_compiler_flag FLAG)
  46   mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
  47   set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
  48   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}")
  49   check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
  50   set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
  51   if(${MANGLED_FLAG})
  52     set(VARIANT ${ARGV1})
  53     if(ARGV1)
  54       string(TOUPPER "_${VARIANT}" VARIANT)
  55     endif()
  56     set(CMAKE_CXX_FLAGS${VARIANT} "${CMAKE_CXX_FLAGS${VARIANT}} ${FLAG}" PARENT_SCOPE)
  57     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
  58     set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
  59     set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${FLAG}" PARENT_SCOPE)
  60     set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} ${FLAG}" PARENT_SCOPE)
  61   else()
  62     message(FATAL_ERROR "Required flag '${FLAG}' is not supported by the compiler")
  63   endif()
  64 endfunction()
  65
  66 function(check_cxx_warning_flag FLAG)
  67   mangle_compiler_flag("${FLAG}" MANGLED_FLAG)
  68   set(OLD_CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS}")
  69   # Add -Werror to ensure the compiler generates an error if the warning flag
  70   # doesn't exist.
  71   set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -Werror ${FLAG}")
  72   check_cxx_compiler_flag("${FLAG}" ${MANGLED_FLAG})
  73   set(CMAKE_REQUIRED_FLAGS "${OLD_CMAKE_REQUIRED_FLAGS}")
  74 endfunction()