From 54e3b32027f1b28cc9871b5ff35c358eaf8cd05f Mon Sep 17 00:00:00 2001 From: Guy Harris Date: Tue, 26 Jan 2016 19:13:44 -0800 Subject: [PATCH] Don't treat Visual Studio specially for linker flags. Have CHECK_C_LINKER_FLAG pass /WX to the linker if we're using MSVC, to force the link to fail if the linker doesn't recognize the flag. Add flags to WIRESHARK_LD_FLAGS even with MSVC; let CHECK_C_LINKER_FLAG figure out whether the flag should be used. While we're at it, fix CHECK_C_LINKER_FLAG to save and restore CMAKE_REQUIRED_LIBRARIES. Change-Id: I7f73b4cc3a28eb14e46c2e1e9ad69f5303754f01 Reviewed-on: https://code.wireshark.org/review/13558 Petri-Dish: Guy Harris Tested-by: Petri Dish Buildbot Reviewed-by: Guy Harris --- CMakeLists.txt | 40 ++++++++++------------------ cmake/modules/CheckCLinkerFlag.cmake | 16 ++++++++--- 2 files changed, 27 insertions(+), 29 deletions(-) diff --git a/CMakeLists.txt b/CMakeLists.txt index 137d52a670..c9a6400a42 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt @@ -595,34 +595,22 @@ else() set (C_UNUSED "" ) endif() +set(WIRESHARK_LD_FLAGS + -Wl,--as-needed + # -flto + # -fwhopr + # -fwhole-program +) +# CMAKE_POSITION_INDEPENDENT_CODE is only supported starting with CMake +# 2.8.9. Do not add -pie automatically for older versions. # -# XXX - at least with the Visual Studio 12 generator, this would test -# whether the flag works with the compiler, but, at least when building -# for Win64, the flag "works", in that the link succeeds, but with a -# warning of an unused linker argument. -# -# So we leave it out for now; maybe there's a way to force the linker to -# fail with unknown arguments, or maybe we have to look for error -# messages in the linker output, the way CHECK_C_COMPILER_FLAG does. +# XXX - are there other compilers that don't support -pie? It's +# not as if the only platforms we support are Windows and Linux.... # -if(NOT CMAKE_C_COMPILER_ID MATCHES "MSVC") - set(WIRESHARK_LD_FLAGS - -Wl,--as-needed - # -flto - # -fwhopr - # -fwhole-program - ) - # CMAKE_POSITION_INDEPENDENT_CODE is only supported starting with CMake - # 2.8.9. Do not add -pie automatically for older versions. - # - # XXX - are there other compilers that don't support -pie? It's - # not as if the only platforms we support are Windows and Linux.... - # - if(NOT CMAKE_VERSION VERSION_LESS "2.8.9") - set(WIRESHARK_LD_FLAGS ${WIRESHARK_LD_FLAGS} - -pie - ) - endif() +if(NOT CMAKE_VERSION VERSION_LESS "2.8.9") + set(WIRESHARK_LD_FLAGS ${WIRESHARK_LD_FLAGS} + -pie + ) endif() include(CheckCLinkerFlag) diff --git a/cmake/modules/CheckCLinkerFlag.cmake b/cmake/modules/CheckCLinkerFlag.cmake index 4a07a8612e..f657a9b884 100644 --- a/cmake/modules/CheckCLinkerFlag.cmake +++ b/cmake/modules/CheckCLinkerFlag.cmake @@ -32,9 +32,19 @@ MACRO (CHECK_C_LINKER_FLAG _FLAG _RESULT) # With 3.2 and later, we could also set policy CMP0056 to NEW and # set CMAKE_EXE_LINKER_FLAGS. # - set(CMAKE_REQUIRED_LIBRARIES "${_FLAG}") - message(status "check linker flag - test linker flags: ${CMAKE_REQUIRED_LIBRARIES}") + set(save_CMAKE_REQUIRED_LIBRARIES "${CMAKE_REQUIRED_LIBRARIES}") + if(CMAKE_C_COMPILER_ID MATCHES "MSVC") + # + # This means the linker is presumably the Microsoft linker; + # we need to pass /WX in order to have the linker fail, + # rather than just complaining and driving on, if it's + # passed a flag it doesn't handle. + # + set(CMAKE_REQUIRED_LIBRARIES "/WX") + endif() + set(CMAKE_REQUIRED_LIBRARIES "${CMAKE_REQUIRED_LIBRARIES} ${_FLAG}") + message(status "check linker flag - test linker flags: ${_FLAG}") check_c_source_compiles("int main() { return 0;}" ${_RESULT}) - set(CMAKE_REQUIRED_LIBRARIES "") + set(CMAKE_REQUIRED_LIBRARIES "${save_CMAKE_REQUIRED_LIBRARIES}") ENDMACRO (CHECK_C_LINKER_FLAG) -- 2.34.1