CMake复用Bazel构建的glog/gflags依赖时编译报错，如何解决？

我有一个基于Bazel的简单项目，使用glog（依赖gflags），执行bazel build main可以成功构建二进制文件。现在想在CMake项目中复用Bazel构建生成的glog和gflags的头文件与库文件，但直接引入Bazel构建输出的虚拟头文件目录后出现编译错误。

Bazel项目代码 #

WORKSPACE文件 #

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

http_archive(
    name = "com_github_gflags_gflags",
    sha256 = "34af2f15cf7367513b352bdcd2493ab14ce43692d2dcd9dfc499492966c64dcf",
    strip_prefix = "gflags-2.2.2",
    urls = ["https://github.com/gflags/gflags/archive/v2.2.2.tar.gz"],
)

http_archive(
    name = "com_github_google_glog",
    sha256 = "122fb6b712808ef43fbf80f75c52a21c9760683dae470154f02bddfc61135022",
    strip_prefix = "glog-0.6.0",
    urls = ["https://github.com/google/glog/archive/v0.6.0.zip"],
)

BUILD文件 #

cc_binary(
    name = "main",
    srcs = ["main.cpp"],
    deps = [
        "@com_github_google_glog//:glog",
    ]
)

main.cpp文件 #

#include <glog/logging.h>

int main() {
    LOG(INFO) << "Hello, World!";
    return 0;
}

CMake尝试代码 #

cmake_minimum_required(VERSION 3.20)
project(btest)

set(CMAKE_CXX_STANDARD 14)

include_directories(/path/to/bazel-out/darwin-fastbuild/bin/external/com_github_google_glog/_virtual_includes/glog)
include_directories(/path/to/bazel-out/darwin-fastbuild/bin/external/com_github_gflags_gflags/_virtual_includes/gflags)

add_executable(main main.cpp)

编译报错信息 #

In file included from ../main.cpp:1:
/path/to/bazel-out/darwin-fastbuild/bin/external/com_github_google_glog/_virtual_includes/glog/glog/logging.h:122:17: error: incomplete type in call to object of type 'struct GLOG_EXPORT'
  LogMessageTime();

1. 放弃使用Bazel虚拟头文件目录 #

Bazel生成的_virtual_includes目录是为自身构建流程设计的，里面的头文件经过预处理，缺失完整的类型定义，直接给CMake使用必然导致编译错误。必须改用原始依赖源码的头文件和Bazel编译产出的库文件。

2. 提取正确的头文件与库文件 #

• 头文件：从Bazel下载的依赖源码目录获取，默认路径为bazel-<你的项目名>/external/com_github_google_glog/src和bazel-<你的项目名>/external/com_github_gflags_gflags/src。
• 库文件：Bazel编译好的静态/动态库位于bazel-out/darwin-fastbuild/bin/external/com_github_google_glog/libglog.a（或.dylib/.so）、bazel-out/darwin-fastbuild/bin/external/com_github_gflags_gflags/libgflags.a路径下。

3. 修改CMakeLists.txt #

调整后的CMake配置如下：

cmake_minimum_required(VERSION 3.20)
project(btest)

set(CMAKE_CXX_STANDARD 14)

# 添加原始依赖的头文件目录
include_directories(/path/to/bazel-<你的项目名>/external/com_github_google_glog/src)
include_directories(/path/to/bazel-<你的项目名>/external/com_github_gflags_gflags/src)

# 链接Bazel编译好的库文件
add_executable(main main.cpp)
target_link_libraries(main
    /path/to/bazel-out/darwin-fastbuild/bin/external/com_github_google_glog/libglog.a
    /path/to/bazel-out/darwin-fastbuild/bin/external/com_github_gflags_gflags/libgflags.a
)

4. 更便捷的替代方案：用Bazel生成CMake导入配置 #

如果不想手动复制文件，可以借助Bazel规则生成CMake可识别的导入文件：

• 在Bazel的BUILD文件中加载相关规则，添加cmake_export_all_build_files()配置，或使用@rules_foreign_cc//tools:cmake.bzl工具导出依赖。
• 执行bazel build @com_github_google_glog//:glog_cmake_export（具体目标名需根据规则调整）生成CMake配置文件，之后在CMake中用find_package()直接导入依赖。

内容的提问来源于stack exchange，提问作者jeffreyveon