Turning on linker flags with CMake

Question

When generating VS2010 targets with CMake, I would like the /LTCG flag turned on (only for release + releasewithdebinfo if possible, but its okay if its on for debug builds)

Answer 1

The use of the "ucm" library seems like a nice approach. I rolled a simple macro that help me uniformly manage linker flags in CMake for all configurations while also allowing compiler-specific use. (Just setting the variable can cause flags to stack up when CMake is configured multiple times.)

macro(ADD_MSVC_LINKER_FLAG flag)
    if(MSVC)
    if(${CMAKE_EXE_LINKER_FLAGS} MATCHES "(${flag}.*)")
        # message("skipping linker flags")
    else()
        set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} ${flag}" CACHE STRING "Linker Flags for Release Builds" FORCE)
    endif()

    if(${CMAKE_SHARED_LINKER_FLAGS} MATCHES "(${flag}.*)")
        # message("skipping linker flags")
    else()
        set(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${flag}" CACHE STRING "Linker Flags for Release Builds" FORCE)
    endif()

    if(${CMAKE_STATIC_LINKER_FLAGS} MATCHES "(${flag}.*)")
        # message("skipping linker flags")
    else()
        set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} ${flag}" CACHE STRING "Linker Flags for Release Builds" FORCE)
    endif()

    if(${CMAKE_MODULE_LINKER_FLAGS} MATCHES "(${flag}.*)")
        # message("skipping linker flags")
    else()
        set(CMAKE_MODULE_LINKER_FLAGS "${CMAKE_MODULE_LINKER_FLAGS} ${flag}" CACHE STRING "Linker Flags for Release Builds" FORCE)
    endif()
    endif()
endmacro()

Other compilers are then supported by creating a compiler-specific macro that checks for the compiler to be in use. That makes it harder to set the right flag on the wrong compiler.

if(CMAKE_COMPILER_IS_GNUCXX)

and

if(${CMAKE_CXX_COMPILER_ID} STREQUAL Clang)