cmake:gperftools性能分析工具find libprofiler 脚本暨profiler的静态连接问题

蔚落 2022-04-18 02:08 373阅读 0赞

[gperftools][]是一个很好用的性能分析工具，但没有提供官方的用于查找profiler库的cmake脚本，所以在基于cmake管理的项目中如果要在系统查找libprofiler库就就要自己写FindPROFILER.cmake脚本。  
将脚本所在的文件夹加入`CMAKE_MODULE_PATH`,调用`find_package(PROFILER)`，就会找到系统中安装的gperftools的libprofiler库，  
脚本不仅按传统方式输出`LIBPROFILER_xxx`系列变量，还会创建`gperftools::profiler` INTERFACE target.方便在项目中引用。

FindPROFILER.cmake

# - Find libprofiler
    # - This module determines the libprofiler library of the system
    # the vairable can be set
    #   LIBPROFILER_STATIC_LINK set true for static link library 为TRUE是要求静态连接
    # The following variables are set if the library found:
    # LIBPROFILER_FOUND - If false do nnt try to use libprofiler.
    # LIBPROFILER_INCLUDE_DIRS - where to find the headfile of library.include文件夹位置
    # LIBPROFILER_LIBRARY_DIRS - where to find the libprofiler library.profiler库所在位置
    # LIBPROFILER_LIBRARIES, the library file name needed to use libprofiler.profiler库及所有依赖库列表
    # LIBPROFILER_LIBRARY - the library needed to use libprofiler. profiler库全路径
    # imported target
    #   gperftools::profiler
    
    if(LIBPROFILER_FOUND)
        return()
    endif()
    include (depcommon)
    # linux系统下调用pkg-config查找profiler
    if (NOT WIN32)
        include(FindPkgConfig)
        unset(_verexp)
        if(LIBPROFILER_FIND_VERSION)
            if(LIBPROFILER_FIND_VERSION_EXACT)        
                  set(_verexp "=${LIBPROFILER_FIND_VERSION}")
            else()
                  set(_verexp ">=${LIBPROFILER_FIND_VERSION}")
            endif()
        endif()
        pkg_check_modules (LIBPROFILER libprofiler${_verexp})
    endif()
    
    if (NOT LIBPROFILER_FOUND)
    	# windows系统下通过查找头文件 gperftools/profiler.h和find_library 查找profiler来实现
        # find the headfile of library
        set (PROFILER_HEADS gperftools/profiler.h)
        find_path (LIBPROFILER_INCLUDE_DIRS ${PROFILER_HEADS})
    
        set (PROFILER_NAMES ${PROFILER_NAMES} profiler)
        find_library (LIBPROFILER_LIBRARY NAMES ${PROFILER_NAMES})
    
        # just find one of dependency, guess other one.
        if (NOT LIBPROFILER_LIBRARY AND LIBPROFILER_INCLUDE_DIRS)
            message ("We just find the headfile, try to guess the library location.")
            set (LIBPROFILER_LIBRARY_DIRS "${LIBPROFILER_INCLUDE_DIRS}/../lib")
            find_library (LIBPROFILER_LIBRARY NAMES ${PROFILER_NAMES} PATHS ${LIBPROFILER_LIBRARY_DIRS})
        elseif (NOT LIBPROFILER_INCLUDE_DIRS AND LIBPROFILER_LIBRARY)
            message ("We just find the lib file, try to guess the include location.")
                    get_filename_component(LIBPROFILER_LIBRARY_DIRS ${LIBPROFILER_LIBRARY} DIRECTORY)
            find_path (LIBPROFILER_INCLUDE_DIRS ${PROFILER_HEADS} "${LIBPROFILER_LIBRARY_DIRS}../included")
        endif()
    
        # find the library.
        if (LIBPROFILER_INCLUDE_DIRS AND LIBPROFILER_LIBRARY)
            if (NOT LIBPROFILER_LIBRARY_DIRS)                        
                get_filename_component(LIBPROFILER_LIBRARY_DIRS ${LIBPROFILER_LIBRARY} DIRECTORY)
            endif ()
            list(APPEND profiler pthread)
        endif()
    else ()
            list(GET MGNCS_LIBRARIES 0 _name)
        find_library (LIBPROFILER_LIBRARY NAMES ${LIBPROFILER_LIBRARIES} PATHS ${LIBPROFILER_LIBRARY_DIRS})
    endif()
    # handle the QUIETLY and REQUIRED arguments and set LIBPROFILER_FOUND to TRUE if
    # all listed variables are TRUE
    include(FindPackageHandleStandardArgs)
    FIND_PACKAGE_HANDLE_STANDARD_ARGS(LIBPROFILER DEFAULT_MSG    LIBPROFILER_LIBRARIES LIBPROFILER_INCLUDE_DIRS)
    
    if(LIBPROFILER_FOUND)
        set(_static_libname libtcmalloc_and_profiler.a)
        find_library (LIBPROFILER_STATIC_LIBRARY NAMES ${_static_libname} PATHS ${LIBPROFILER_LIBRARY_DIRS})
        if(NOT LIBPROFILER_FIND_QUIETLY)
            message(STATUS "  -I: ${LIBPROFILER_INCLUDE_DIRS}")
            message(STATUS "  -L: ${LIBPROFILER_LIBRARY_DIRS}")
            message(STATUS "  -l: ${LIBPROFILER_LIBRARIES}")
        endif()
        find_library (LIBPROFILER_LIBRARY NAMES ${LIBPROFILER_LIBRARIES} PATHS ${LIBPROFILER_LIBRARY_DIRS})
    
        # create imported target
        if (NOT TARGET gperftools::profiler)
            add_library(gperftools::profiler INTERFACE IMPORTED)
            if(LIBPROFILER_STATIC_LINK)
                # for linking static profiler,must use libtcmalloc_and_profiler.a,see also README gperftools
                set(_link_libs ${LIBPROFILER_STATIC_LDFLAGS})
                if(NOT LIBPROFILER_STATIC_LIBRARY)
                    message(FATAL_ERROR "NOT FOUND static library for profiler:${_static_libname} ")
                endif()
          # 替换 profiler 为 :libtcmalloc_and_profiler.a
                string(REPLACE profiler :${_static_libname} _link_libs "${_link_libs}")
            else()
                set(_link_libs ${LIBPROFILER_LDFLAGS})
            endif()
            set_target_properties(gperftools::profiler PROPERTIES
                INTERFACE_COMPILE_OPTIONS "${LIBPROFILER_CFLAGS_OTHER}"
                INTERFACE_INCLUDE_DIRECTORIES "${LIBPROFILER_INCLUDE_DIRS}"
                INTERFACE_LINK_LIBRARIES   "${_link_libs}"
                )
            if(NOT LIBPROFILER_FIND_QUIETLY)
                message(STATUS "IMPORTED TARGET: gperftools::profiler,link libraies ${_link_libs}")
            endif()
        endif ()
        
    endif(LIBPROFILER_FOUND)

# 静态连接profiler #

关于静态连接profiler，之前看过不少博客文章，都指出gperftools不支持静态连接profiler库。但我查看了gperftools(2.7)的官方说明，提供了静态连接profiler库的方法：

下面的英文说明来自gperftools的官方说明([https://github.com/gperftools/gperftools/blob/master/README][https_github.com_gperftools_gperftools_blob_master_README])

EVERYTHING IN ONE
    -----------------
    If you want the CPU profiler, heap profiler, and heap leak-checker to
    all be available for your application, you can do:
       gcc -o myapp ... -lprofiler -ltcmalloc
    
    However, if you have a reason to use the static versions of the
    library, this two-library linking won't work:
       gcc -o myapp ... /usr/lib/libprofiler.a /usr/lib/libtcmalloc.a  # errors!
    
    Instead, use the special libtcmalloc_and_profiler library, which we
    make for just this purpose:
       gcc -o myapp ... /usr/lib/libtcmalloc_and_profiler.a

确实直接静态连接libprofiler.a是不行的，但这里也明确给出了静态连接profiler的方式：用`libtcmalloc_and_profiler.a`替代`libprofiler.a`。

所以在上面的cmake脚本中当`LIBPROFILER_STATIC_LINK` 为TRUE时，会替换 `profiler` 为 `:libtcmalloc_and_profiler.a`

[gperftools]: https://github.com/gperftools/gperftools
[https_github.com_gperftools_gperftools_blob_master_README]: https://github.com/gperftools/gperftools/blob/master/README