问用Bazel构建LLVM
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提问于 2018-07-29 16:36:22

回答 1查看 1.8K关注 0票数 2

我有一个正在使用CMake的项目，我想把它切换到Bazel。主要依赖项是LLVM，我使用它生成LLVM IR。环顾四周，似乎没有很多关于这方面的指导，因为只有TensorFlow似乎使用Bazel的LLVM (据我所知，自动生成它的配置)。我还发现了一个关于bazel的文章-讨论，它讨论了一个类似的问题，尽管我复制它的尝试失败了。

目前，我最好的运行方式必须是这个(fetcher.bzl)：

def _impl(ctx):
    # Download LLVM master
    ctx.download_and_extract(url = "https://github.com/llvm-mirror/llvm/archive/master.zip")

    # Run `cmake llvm-master` to generate configuration.
    ctx.execute(["cmake", "llvm-master"])

    # The bazel-discuss thread says to delete llvm-master, but I've
    # found that only generated files are pulled out of master, so all
    # the non-generated ones get dropped if I delete this.
    # ctx.execute(["rm", "-r", "llvm-master"])

    # Generate a BUILD file for the LLVM dependency.
    ctx.file('BUILD', """
# Build a library with all the LLVM code in it.
cc_library(
    name = "lib",
    srcs = glob(["**/*.cpp"]),
    hdrs = glob(["**/*.h"]),

    # Include the x86 target and all include files.
    # Add those under llvm-master/... as well because only built files
    # seem to appear under include/...
    copts = [
        "-Ilib/Target/X86",
        "-Iinclude",
        "-Illvm-master/lib/Target/X86",
        "-Illvm-master/include",
    ],

    # Include here as well, not sure whether this or copts is
    # actually doing the work.
    includes = [
        "include",
        "llvm-master/include",
    ],
    visibility = ["//visibility:public"],
    # Currently picking up some gtest targets, I have that dependency
    # already, so just link it here until I filter those out.
    deps = [
        "@gtest//:gtest_main",
    ],
)
""")

    # Generate an empty workspace file
    ctx.file('WORKSPACE', '')

get_llvm = repository_rule(implementation = _impl)

然后，我的WORKSPACE文件如下所示：

load(":fetcher.bzl", "get_llvm")

git_repository(
    name = "gflags",
    commit = "46f73f88b18aee341538c0dfc22b1710a6abedef", # 2.2.1
    remote = "https://github.com/gflags/gflags.git",
)

new_http_archive(
    name = "gtest",
    url = "https://github.com/google/googletest/archive/release-1.8.0.zip",
    sha256 = "f3ed3b58511efd272eb074a3a6d6fb79d7c2e6a0e374323d1e6bcbcc1ef141bf",
    build_file = "gtest.BUILD",
    strip_prefix = "googletest-release-1.8.0",
)

get_llvm(name = "llvm")

然后，我将使用bazel build @llvm//:lib --verbose_failures运行这个程序。

我会不断地从丢失的头文件中得到错误。最后，我发现运行cmake llvm-master会将许多头文件生成到当前目录中，但似乎将非生成的头文件保留在llvm-master/中。我在llvm-master/下添加了相同的包含目录，这似乎捕获了很多文件。但是，目前看来tblgen没有运行，而且我仍然缺少编译所需的关键头。我目前的错误是：

In file included from external/llvm/llvm-master/include/llvm/CodeGen/MachineOperand.h:18:0,
                 from external/llvm/llvm-master/include/llvm/CodeGen/MachineInstr.h:24,
                 from external/llvm/llvm-master/include/llvm/CodeGen/MachineBasicBlock.h:22,
                 from external/llvm/llvm-master/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h:20,
                 from external/llvm/llvm-master/include/llvm/CodeGen/GlobalISel/ConstantFoldingMIRBuilder.h:13,
                 from external/llvm/llvm-master/unittests/CodeGen/GlobalISel/PatternMatchTest.cpp:10:
external/llvm/llvm-master/include/llvm/IR/Intrinsics.h:42:38: fatal error: llvm/IR/IntrinsicEnums.inc: No such file or directory