OpenBLAS:改进OpenBLASConfig.cmake生成方式,解除cmake脚本的路径依赖

男娘i 2022-06-13 14:14 418阅读 0赞

# 问题描述 #

当我们用OpenBLAS提供的Makefile进行编译，并用`make install PREFIX=/you/install/path`,安装到指定的路径时，你会发现，`/you/install/path/lib/cmake/openblas/OpenBLASConfig.cmake`文件中OpenBLAS\_INCLUDE\_DIRS和OpenBLAS\_LIBRARIES的值都是绝对路径,如下：

/you/install/path/lib/cmake/openblas/OpenBLASConfig.cmake  
**(linux下生成动态库)**

SET(OpenBLAS_VERSION "0.2.18")
    SET(OpenBLAS_INCLUDE_DIRS /home/hadoop/Desktop/caffe-static/release/OpenBLAS_linux_x86_64/include)
    SET(OpenBLAS_LIBRARIES /home/hadoop/Desktop/caffe-static/release/OpenBLAS_linux_x86_64/bin/libopenblas.so)

**(linux下生成静态库)**

**(windows下生成动态库)**

SET(OpenBLAS_VERSION "0.2.18")
    SET(OpenBLAS_INCLUDE_DIRS D:/caffe-static/release/OpenBLAS_windows_vc140_x86_mt/include)
    SET(OpenBLAS_LIBRARIES D:/caffe-static/release/OpenBLAS_windows_vc140_x86_mt/bin/libopenblas.dll)

> 关于windows下如何用MinGW编译OpenBLAS，参见我的另一篇博客[《Windows下MSYS2中编译OpenBLAS过程记录》][Windows_MSYS2_OpenBLAS]

如果你编译OpenBLAS只是在本机使用，那没啥问题，如果想把这个编译好的OpenBLAS 移到别的位置或提供给别人使用，并且也是用cmake编译项目。那么问题就来了，因为OpenBLASConfig.cmake中的路径依赖问题，导致cmake脚本中调用`find_package( OpenBLAS NO_MODULE )`返回的OpenBLAS\_LIBRARIES和OpenBLAS\_LIBRARIES的值都是错的!

而且你发现没有？上面Windows下生成的OpenBLASConfig.cmake中OpenBLAS\_LIBRARIES的值居然是.dll的路径。而不是动态库导入库(import library)(.dll.a)的路径,也就是说OpenBLAS在生成OpenBLASConfig.cmake没有考虑到linux和windows的区别，只是按linux的方式将OpenBLAS\_LIBRARIES置为静态库/动态库(.a,.so,dll)的路径。

如果你是用手工在Visual Studio中创建工程并设置工程参数，那么这都不是问题，对你没有任何影响，但如果你像我一样，用cmake进行工程编译，这是个很要命的问题，因为cmake根据这些错误的信息无法生成正确的Makefile,当然也不能正常编译。

# 原因分析 #

怎么办呢?指望OpenBLAS官方修改这个问题怕是来不及了,只能自己想办法解决。  
于是我仔细研究了OpenBLAS的Makefile的体系。算是基本搞清楚了OpenBLAS源码下那一大堆Makefile.\*的作用。最终找到了问题的关键点：  
Makefile.install 这个文件是OpenBLAS的安装脚本，当执行 `make install`时其实就是执行这个脚本来执行安装工作的。

而在这其中生成OpenBLASConfig.cmake的代码就是如下几行(line 97-116 OpenBLAS 0.2.18)  
(中文注释为本文作者所加)

#Generating OpenBLASConfig.cmake
        @echo Generating $(OPENBLAS_CMAKE_CONFIG) in $(DESTDIR)$(OPENBLAS_CMAKE_DIR)
        # 对应OpenBLASConfig.cmake中line 1
        @echo "SET(OpenBLAS_VERSION \"${VERSION}\")" > $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)    
        # 对应OpenBLASConfig.cmake中line 2
        @echo "SET(OpenBLAS_INCLUDE_DIRS ${OPENBLAS_INCLUDE_DIR})" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    
    ifndef NO_SHARED
    #ifeq logical or
    # 判断操作系统将OpenBLAS_LIBRARIES置为动态库文件路径
    ifeq ($(OSNAME), $(filter $(OSNAME),Linux FreeBSD NetBSD))
        # 对应OpenBLASConfig.cmake中line 3
        @echo "SET(OpenBLAS_LIBRARIES ${OPENBLAS_LIBRARY_DIR}/$(LIBPREFIX).so)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    ifeq ($(OSNAME), $(filter $(OSNAME),WINNT CYGWIN_NT))
        # 对应OpenBLASConfig.cmake中line 3
        # 这里 LIBDLLNAME   = $(LIBPREFIX).dll 参见 Makefile.system
        @echo "SET(OpenBLAS_LIBRARIES ${OPENBLAS_BINARY_DIR}/$(LIBDLLNAME))" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    ifeq ($(OSNAME), Darwin)
        # 对应OpenBLASConfig.cmake中line 3
        @echo "SET(OpenBLAS_LIBRARIES ${OPENBLAS_LIBRARY_DIR}/$(LIBPREFIX).dylib)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    else
    # 将OpenBLAS_LIBRARIES置为静态库文件路径
    #only static
        # 对应OpenBLASConfig.cmake中line 3
        @echo "SET(OpenBLAS_LIBRARIES ${OPENBLAS_LIBRARY_DIR}/$(LIBPREFIX).$(LIBSUFFIX))" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif

`OPENBLAS_INCLUDE_DIR,OPENBLAS_LIBRARY_DIR,OPENBLAS_BINARY_DIR`在Makefile.install文件开头定义 (line 8-10 OpenBLAS 0.2.18)

上面的三行`@echo`的代码清晰的对应着OpenBLASConfig.cmake中的三行代码，由此我们理解为什么OpenBLASConfig.cmake中的路径都是绝对路径，而且windows下OpenBLAS\_LIBRARIES的值是.dll文件的路径了。

# 解决方法 #

原因搞清楚就好办了，要解决问题，只要修改上面这段代码，改进生成OpenBLASConfig.cmake的逻辑就可以了。

以下是上面代码(Makefile.install)修改后的版本：

#Generating OpenBLASConfig.cmake
    # modified by guyadong for windows build
        @echo Generating $(OPENBLAS_CMAKE_CONFIG) in $(DESTDIR)$(OPENBLAS_CMAKE_DIR)  
        @echo "SET(OpenBLAS_VERSION \"${VERSION}\")" > $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)  
        @echo "# modified by guyadong,use relative path instead of absolute path" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)   
        @echo "# Compute the installation prefix relative to this file." >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)    
        @echo "get_filename_component(_IMPORT_PREFIX \"\$${CMAKE_CURRENT_LIST_FILE}\" PATH)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "get_filename_component(_IMPORT_PREFIX \"\$${_IMPORT_PREFIX}\" PATH)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)  
        @echo "get_filename_component(_IMPORT_PREFIX \"\$${_IMPORT_PREFIX}\" PATH)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)  
        @echo "get_filename_component(_IMPORT_PREFIX \"\$${_IMPORT_PREFIX}\" PATH)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)  
        @echo "if(_IMPORT_PREFIX STREQUAL \"/\")" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " set(_IMPORT_PREFIX \"\")" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "endif()" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "SET(OpenBLAS_INCLUDE_DIRS \$${_IMPORT_PREFIX}/include)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    
    ifndef NO_SHARED
    #ifeq logical or
    ifeq ($(OSNAME), $(filter $(OSNAME),Linux FreeBSD NetBSD))
        @echo "SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/lib/$(LIBPREFIX).so)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    ifeq ($(OSNAME), $(filter $(OSNAME),WINNT CYGWIN_NT))
    # windows下编译时生成条件判断语句
        @echo "# use dynamic import library if MSVC" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)    
        @echo "if(MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/lib/$(LIBDLLNAME).a)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "else(MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/bin/$(LIBDLLNAME))" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "endif(MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "SET(OPENBLAS_IS_DYNAMIC true)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    ifeq ($(OSNAME), Darwin)
        @echo "SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/lib/$(LIBPREFIX).dylib)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
    else
    #only static
        @echo "SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/lib/$(LIBPREFIX).$(LIBSUFFIX))" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    # windows下编译时生成条件判断语句
    ifeq ($(OSNAME), $(filter $(OSNAME),WINNT CYGWIN_NT))    
        @echo "if(MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " message(STATUS \"OpenBLAS_LIBRARIES(static library):\$${OpenBLAS_LIBRARIES}\" )" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " message(FATAL_ERROR \"With Visual Studio, only dynamic linking is supported,please reinstall OpenBLAS without NO_STATIC=1\" )" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "endif(MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "SET(OPENBLAS_IS_DYNAMIC false)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif   
    endif
    ifeq ($(OSNAME), $(filter $(OSNAME),WINNT CYGWIN_NT))    
        @echo "# if OpenBlas_USE_STATIC is true,force to use static library with MinGW" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "if(OPENBLAS_IS_DYNAMIC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " if(EXISTS \"\$${_IMPORT_PREFIX}/lib/$(LIBPREFIX).$(LIBSUFFIX)\" AND OpenBlas_USE_STATIC AND NOT MSVC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "     MESSAGE(STATUS \"use OpenBlas static library\")" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "     SET(OpenBLAS_LIBRARIES \$${_IMPORT_PREFIX}/lib/$(LIBPREFIX).$(LIBSUFFIX))" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo " endif()" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "endif(OPENBLAS_IS_DYNAMIC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
        @echo "unset(OPENBLAS_IS_DYNAMIC)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)
    endif
        @echo "unset(_IMPORT_PREFIX)" >> $(DESTDIR)$(OPENBLAS_CMAKE_DIR)/$(OPENBLAS_CMAKE_CONFIG)

经过上面的修改，再重新执行`make install PREFIX=/you/install/path`,生成的OpenBLASConfig.cmake(中文注释为本文作者所加)  
**(linux下生成静态态库)**

**(windows下生成动态库)**

# modified by guyadong,use relative path instead of absolute path
    # Compute the installation prefix relative to this file.
    # 三次调用 get_filename_component 计算 OpenBLAS安装路径
    # _IMPORT_PREFIX为OpenBLAS安装路径
    get_filename_component(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_DIR}" PATH)
    get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
    get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
    if(_IMPORT_PREFIX STREQUAL "/")
        set(_IMPORT_PREFIX "")
    endif()
    SET(OpenBLAS_INCLUDE_DIRS ${_IMPORT_PREFIX}/include)
    # 判断编译器类型，MSVC下置为import library(.dll.a) ,否则(MinGW)置为.dll
    if(MSVC)
        SET(OpenBLAS_LIBRARIES ${_IMPORT_PREFIX}/lib/libopenblas.dll.a)
    else(MSVC)
        SET(OpenBLAS_LIBRARIES ${_IMPORT_PREFIX}/bin/libopenblas.dll)
    endif(MSVC)
    SET(openblas_is_dynamic true)
    # if OpenBlas_USE_STATIC is true,force to use static library with MinGW
    if(openblas_is_dynamic)
        # 使用MinGW编译时,如果定义了OpenBlas_USE_STATIC,则置为静态库
        if(EXISTS "${_IMPORT_PREFIX}/lib/libopenblas.a" AND OpenBlas_USE_STATIC AND NOT MSVC)
            SET(OpenBLAS_LIBRARIES ${_IMPORT_PREFIX}/lib/libopenblas.a)
        endif()
    endif(openblas_is_dynamic)
    unset(openblas_is_dynamic)
    unset(_IMPORT_PREFIX)

# 完整代码 #

修改后的OpenBLAS Makefile.install完整代码参见 ：

> [https://gitee.com/l0km/caffe-static/tree/master/patch/OpenBLAS-0.2.18/Makefile.install][https_gitee.com_l0km_caffe-static_tree_master_patch_OpenBLAS-0.2.18_Makefile.install]

# 后记 #

本文对 Makefile.install的修改已经申请 Pull Request ,如果被接受，后续OpenBLAS的版本就不需要这样手工修改了。  
[https://github.com/xianyi/OpenBLAS/pull/1231][https_github.com_xianyi_OpenBLAS_pull_1231]

[Windows_MSYS2_OpenBLAS]: http://blog.csdn.net/10km/article/details/74784322
[https_gitee.com_l0km_caffe-static_tree_master_patch_OpenBLAS-0.2.18_Makefile.install]: https://gitee.com/l0km/caffe-static/tree/master/patch/OpenBLAS-0.2.18/Makefile.install
[https_github.com_xianyi_OpenBLAS_pull_1231]: https://github.com/xianyi/OpenBLAS/pull/1231