cmake_modules/compilerchecks.cmake
author Wuzzy <Wuzzy2@mail.ru>
Sat, 06 Jun 2020 15:40:51 +0200
changeset 15597 6e72bd61002e
parent 15451 3102d95a870e
permissions -rw-r--r--
Disable gfMoreWind for land objects on turn end only after a fixed-time delay 15s sounds much, but it's the average amount for gfMineStrike mines to settle naturally. And it would be very confusing to see falling mines suddenly not caring about gfMoreWind for no apparent reason. Note this whole thing is a giant hack anyway, to prevent a turn being blocked by infinitely bouncing mines. The better solution would be to help gfMoreWind-affected land objects settle naturally more reliably even under extreme wind. But this commit is "good enough" for now. If you don't like the delay, you can always tweak the constant.


#TESTING TIME
include(CheckCCompilerFlag)
#when you need to check for a linker flag, just leave the argument of "check_c_compiler_flag" empty

# CMAKE_C{XX}_FLAGS is for compiler flags (c and c++)
# CMAKE_EXE_LINKER_FLAGS is for linker flags (also add them to pascal_flags and haskell_flags)
# CMAKE_SHARED_LIBRARY_<lang>_FLAGS same but for shared libraries

#TODO: should there be two different checks for C and CXX?
#TODO: can the various if(platform) be avoided in some way?


if(NOT (WIN32 OR (CMAKE_SYSTEM_NAME MATCHES BSD.OS) OR (CMAKE_SYSTEM_NAME MATCHES FreeBSD)))
    #stack protection, when found it needs to go in the linker flags too
    #it is disabled on win32 because it adds a dll and messes with linker
    #some bsd installations reported problems too
    #(see 822312 654424 on bugzilla.redhat.com)
    check_c_compiler_flag("-fstack-protector-all -fstack-protector" HAVE_STACKPROTECTOR)
    if(HAVE_STACKPROTECTOR)
        add_flag_append(CMAKE_C_FLAGS "-fstack-protector-all -fstack-protector")
        add_flag_append(CMAKE_CXX_FLAGS "-fstack-protector-all -fstack-protector")
    endif()
endif()



if(UNIX)
    #symbol visibility
    check_c_compiler_flag("-fvisibility=hidden" HAVE_VISIBILITY)
    if(HAVE_VISIBILITY)
        add_flag_append(CMAKE_C_FLAGS "-fvisibility=hidden")
        add_flag_append(CMAKE_CXX_FLAGS "-fvisibility=hidden")
    endif()

    #check for noexecstack on ELF, Gentoo security
    set(CMAKE_REQUIRED_FLAGS "-Wl,-znoexecstack")
    check_c_compiler_flag("" HAVE_NOEXECSTACK)
    if(HAVE_NOEXECSTACK)
        add_linker_flag("-znoexecstack")
    endif()

    #check for origin on ELF, BSD $ORIGIN support
    set(CMAKE_REQUIRED_FLAGS "-Wl,-zorigin")
    check_c_compiler_flag("" HAVE_ORIGIN)
    if(HAVE_ORIGIN)
        add_linker_flag("-zorigin")
    endif()

    #check for full relro on ELF, Debian security
    set(CMAKE_REQUIRED_FLAGS "-Wl,-zrelro,-znow")
    check_c_compiler_flag("" HAVE_RELROFULL)
    if(HAVE_RELROFULL)
        add_linker_flag("-zrelro")
        add_linker_flag("-znow")
    else()
        #if full relro is not available, try partial relro
        set(CMAKE_REQUIRED_FLAGS "-Wl,-zrelro")
        check_c_compiler_flag("" HAVE_RELROPARTIAL)
        if(HAVE_RELROPARTIAL)
            add_linker_flag("-zrelro")
        endif()
    endif()

    if(CMAKE_BUILD_TYPE STREQUAL "Release" OR CMAKE_BUILD_TYPE STREQUAL "RelWithDebInfo")
        set(CMAKE_REQUIRED_FLAGS "-Wl,--as-needed")
        check_c_compiler_flag("" HAVE_ASNEEDED)
        if(HAVE_ASNEEDED)
            add_linker_flag("--as-needed")
        endif()
    endif()
else(UNIX)
    #check for ASLR on Windows Vista or later, requires binutils >= 2.20
    set(CMAKE_REQUIRED_FLAGS "-Wl,--nxcompat")
    check_c_compiler_flag("" HAVE_WINASLR)
    if(HAVE_WINASLR)
        add_linker_flag("--nxcompat")
    endif()

    #check for DEP on Windows XP SP2 or later, requires binutils >= 2.20
    set(CMAKE_REQUIRED_FLAGS "-Wl,--dynamicbase")
    check_c_compiler_flag("" HAVE_WINDEP)
    if(HAVE_WINDEP)
        add_linker_flag("--dynamicbase")
    endif()
endif(UNIX)


#always unset or these flags will be spread everywhere
unset(CMAKE_REQUIRED_FLAGS)