使用CMake编译并添加二进制文件中的目标文件

Question

我正在用C++编写Excel文件构建器.

我有我需要的一切工作,但我仍然依赖一个外部空的.xlsx文件,我解压缩,迭代,并根据需要添加数据来创建最终文件.

我想通过将.xlsx文件转换为可执行文件的.rodata部分中的二进制blob来删除此依赖项,方法是将其首先转换为对象文件,如下所示:

$ ld -r -b binary -o template.o template.xlsx
$ objcopy --rename-section .data=.rodata,alloc,load,readonly,data,contents template.o template.o

我从博客文章http://www.burtonini.com/blog/computers/ld-blobs-2007-07-13-15-50获得了这些信息.

第二步是将它链接到二进制文件,我可以使用它ld.

如何使用CMake自动执行这两个步骤？

我目前不知道如何ld在第一步中运行如上所述的特定命令,并且我已尝试在第二步中添加files/template.o到我的target_link_libraries,但ld只是说:

/usr/bin/ld: cannot find -lfiles/template.o

我将以下自定义命令添加到我的CMakeLists.txt:

add_custom_command(OUTPUT files/template.o
      COMMAND ld -r -b binary -o files/template.o files/template.xlsx
      COMMAND objcopy --rename-section .data=.rodata,alloc,load,readonly,data,contents files/template.o files/template.o)

并将文件/ template.o添加到add_executable调用.

不幸的是,CMake说:

ld:无法打开输出文件files/template.o:没有这样的文件或目录

据我所知,OUTPUT命令add_custom_command允许我们告诉CMake COMMAND命令正在创建什么文件.所以我现在有点困惑.

我更新了CMakeLists.txt文件并添加了一个目标,以确保模板文件已构建:

add_custom_target(run ALL
    DEPENDS template.o)

并且依赖于确保它在excelbuilder目标之前构建:

add_dependencies(excelbuilder run)

我还更新了自定义命令,如下所示:

add_custom_command(OUTPUT template.o
      COMMAND ld -r -b binary -o template.o ${CMAKE_CURRENT_SOURCE_DIR}/files/template.xlsx
      COMMAND objcopy --rename-section .data=.rodata,alloc,load,readonly,data,contents template.o template.o)

当我运行它时,输出如下(使VERBOSE = 1)

$ make VERBOSE=1
/usr/bin/cmake -H/home/ravloony/projects/excelparser -B/home/ravloony/projects/excelparser/build --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/cmake -E cmake_progress_start /home/ravloony/projects/excelparser/build/CMakeFiles /home/ravloony/projects/excelparser/build/CMakeFiles/progress.marks
make -f CMakeFiles/Makefile2 all
make[1]: Entering directory `/home/ravloony/projects/excelparser/build'
make -f src/lib/minizip/CMakeFiles/minizip_1-1.dir/build.make src/lib/minizip/CMakeFiles/minizip_1-1.dir/depend
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
cd /home/ravloony/projects/excelparser/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/ravloony/projects/excelparser /home/ravloony/projects/excelparser/src/lib/minizip /home/ravloony/projects/excelparser/build /home/ravloony/projects/excelparser/build/src/lib/minizip /home/ravloony/projects/excelparser/build/src/lib/minizip/CMakeFiles/minizip_1-1.dir/DependInfo.cmake --color=
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
make -f src/lib/minizip/CMakeFiles/minizip_1-1.dir/build.make src/lib/minizip/CMakeFiles/minizip_1-1.dir/build
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
make[2]: Nothing to be done for `src/lib/minizip/CMakeFiles/minizip_1-1.dir/build'.
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
/usr/bin/cmake -E cmake_progress_report /home/ravloony/projects/excelparser/build/CMakeFiles  17 18 19 20 21
[ 22%] Built target minizip_1-1
make -f CMakeFiles/run.dir/build.make CMakeFiles/run.dir/depend
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
cd /home/ravloony/projects/excelparser/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/ravloony/projects/excelparser /home/ravloony/projects/excelparser /home/ravloony/projects/excelparser/build /home/ravloony/projects/excelparser/build /home/ravloony/projects/excelparser/build/CMakeFiles/run.dir/DependInfo.cmake --color=
Dependee "/home/ravloony/projects/excelparser/build/CMakeFiles/run.dir/DependInfo.cmake" is newer than depender "/home/ravloony/projects/excelparser/build/CMakeFiles/run.dir/depend.internal".
Dependee "/home/ravloony/projects/excelparser/build/CMakeFiles/CMakeDirectoryInformation.cmake" is newer than depender "/home/ravloony/projects/excelparser/build/CMakeFiles/run.dir/depend.internal".
Scanning dependencies of target run
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
make -f CMakeFiles/run.dir/build.make CMakeFiles/run.dir/build
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
/usr/bin/cmake -E cmake_progress_report /home/ravloony/projects/excelparser/build/CMakeFiles 22
[ 27%] Generating template.o
ld -r -b binary -o template.o /home/ravloony/projects/excelparser/files/template.xlsx
objcopy --rename-section .data=.rodata,alloc,load,readonly,data,contents template.o template.o
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
/usr/bin/cmake -E cmake_progress_report /home/ravloony/projects/excelparser/build/CMakeFiles  22
[ 27%] Built target run
make -f CMakeFiles/excelbuilder.dir/build.make CMakeFiles/excelbuilder.dir/depend
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
cd /home/ravloony/projects/excelparser/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/ravloony/projects/excelparser /home/ravloony/projects/excelparser /home/ravloony/projects/excelparser/build /home/ravloony/projects/excelparser/build /home/ravloony/projects/excelparser/build/CMakeFiles/excelbuilder.dir/DependInfo.cmake --color=
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
make -f CMakeFiles/excelbuilder.dir/build.make CMakeFiles/excelbuilder.dir/build
make[2]: Entering directory `/home/ravloony/projects/excelparser/build'
Linking CXX executable excelbuilder
/usr/bin/cmake -E cmake_link_script CMakeFiles/excelbuilder.dir/link.txt --verbose=1
/usr/bin/c++   -std=c++0x  -g -ftest-coverage -fprofile-arcs -fpermissive    CMakeFiles/excelbuilder.dir/src/common/exception.cpp.o CMakeFiles/excelbuilder.dir/src/excelbuilder/retriever.cpp.o CMakeFiles/excelbuilder.dir/src/excelbuilder/xlsx.cpp.o CMakeFiles/excelbuilder.dir/src/common/config.cpp.o CMakeFiles/excelbuilder.dir/src/excelbuilder/main.cpp.o  -o excelbuilder -rdynamic src/lib/minizip/libminizip_1-1.so -ltinyxml2 -lmysqlcppconn -lboost_regex-mt -ltemplate.o -lz -Wl,-rpath,/home/ravloony/projects/excelparser/build/src/lib/minizip
/usr/bin/ld: cannot find -ltemplate.o
collect2: error: ld returned 1 exit status
make[2]: *** [excelbuilder] Error 1
make[2]: Leaving directory `/home/ravloony/projects/excelparser/build'
make[1]: *** [CMakeFiles/excelbuilder.dir/all] Error 2
make[1]: Leaving directory `/home/ravloony/projects/excelparser/build'
make: *** [all] Error 2

但文件template.o已正确生成并位于文件夹中.似乎ld期待一个系统库.

Answer 1

最后,这就是我做到的.

add_custom_command(OUTPUT template.o
      COMMAND cd ${CMAKE_CURRENT_SOURCE_DIR}/files && ld -r -b binary -o ${CMAKE_CURRENT_BINARY_DIR}/template.o template.xlsx
      COMMAND objcopy --rename-section .data=.rodata,alloc,load,readonly,data,contents ${CMAKE_CURRENT_BINARY_DIR}/template.o ${CMAKE_CURRENT_BINARY_DIR}/template.o)

这些cd命令是因为ld根据传递给输入文件的完整路径将自动声明的变量的名称设置为某些内容.因此,如果输入文件是/home/user/project/files/template.xlsx,变量将是类似的_binary_home_user_project_files_template_xlsx_start.便携式编译并不酷.

add_library(template
        STATIC
        template.o)

告诉链接器将目标文件编译成二进制文件.这也增加了一个名为的目标template.

然后

SET_SOURCE_FILES_PROPERTIES(
  template.o
  PROPERTIES
  EXTERNAL_OBJECT true
  GENERATED true
  )

告诉CMake不要编译在构建时生成的文件.

SET_TARGET_PROPERTIES(
  template
  PROPERTIES
  LINKER_LANGUAGE C 
  )

否则我们会得到一条错误消息,因为CMake无法从".o"-suffix中发现它是我们需要的C链接器.

然后在我的target_link_libraries步骤中,我只是添加template为目标.

target_link_libraries (excelbuilder
            ${MINIZIP_LIB_NAME}
            ${TINYXML_LIBRARIES}
            ${MYSQLCONNECTORCPP_LIBRARY}
            ${Boost_LIBRARIES}
            template
            )