diff options
Diffstat (limited to 'Modules/Compiler/GNU.cmake')
| -rw-r--r-- | Modules/Compiler/GNU.cmake | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/Modules/Compiler/GNU.cmake b/Modules/Compiler/GNU.cmake index b67002c..4b1c598 100644 --- a/Modules/Compiler/GNU.cmake +++ b/Modules/Compiler/GNU.cmake @@ -45,4 +45,43 @@ macro(__compiler_gnu lang) if(NOT APPLE OR NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4) # work around #4462 set(CMAKE_INCLUDE_SYSTEM_FLAG_${lang} "-isystem ") endif() + + set(_CMAKE_IPO_SUPPORTED_BY_CMAKE YES) + set(_CMAKE_IPO_MAY_BE_SUPPORTED_BY_COMPILER NO) + + # '-flto' introduced since GCC 4.5: + # * https://gcc.gnu.org/onlinedocs/gcc-4.4.7/gcc/Option-Summary.html (no) + # * https://gcc.gnu.org/onlinedocs/gcc-4.5.4/gcc/Option-Summary.html (yes) + if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4.5) + set(_CMAKE_IPO_MAY_BE_SUPPORTED_BY_COMPILER YES) + set(__lto_flags -flto) + + if(NOT CMAKE_${lang}_COMPILER_VERSION VERSION_LESS 4.7) + # '-ffat-lto-objects' introduced since GCC 4.7: + # * https://gcc.gnu.org/onlinedocs/gcc-4.6.4/gcc/Option-Summary.html (no) + # * https://gcc.gnu.org/onlinedocs/gcc-4.7.4/gcc/Option-Summary.html (yes) + list(APPEND __lto_flags -fno-fat-lto-objects) + endif() + + set(CMAKE_${lang}_COMPILE_OPTIONS_IPO ${__lto_flags}) + + # Need to use version of 'ar'/'ranlib' with plugin support. + # Quote from [documentation][1]: + # + # To create static libraries suitable for LTO, + # use gcc-ar and gcc-ranlib instead of ar and ranlib + # + # [1]: https://gcc.gnu.org/onlinedocs/gcc-4.9.4/gcc/Optimize-Options.html + set(CMAKE_${lang}_ARCHIVE_CREATE_IPO + "${CMAKE_GCC_AR} cr <TARGET> <LINK_FLAGS> <OBJECTS>" + ) + + set(CMAKE_${lang}_ARCHIVE_APPEND_IPO + "${CMAKE_GCC_AR} r <TARGET> <LINK_FLAGS> <OBJECTS>" + ) + + set(CMAKE_${lang}_ARCHIVE_FINISH_IPO + "${CMAKE_GCC_RANLIB} <TARGET>" + ) + endif() endmacro() |