Export compile commands from Bazel

This repository provides a plugin for Bazel to create a Clang tooling compatible JSON compilation database (compile_commands.json).

YouCompleteMe can use the same file for semantic completion.

Note that in order to use the compile_commands.json generated by this plugin with Clang tooling, you need to set up Bazel to use Clang for compiling C and C++ in the first place (export CC=clang++ seems to work for me).

Disclaimer

I am using this for my own C++ projects and thought it might be useful to others. Use at your own risk. Only tested on Linux with Bazel 0.5.1.

Usage

Import the repository into your WORKSPACE:

http_archive(
    name = "bazel_compilation_database",
    url = "https://github.com/curiousleo/bazel_compilation_database/archive/9ccdbe1252050a7ddbd146dd425f4fb48251f378.zip",
    sha256 = "f1e0d4ed4590af2ff84f258acdcddae7aa1047e5531ec704fc271b0dc2b45898",
    strip_prefix = "bazel_compilation_database-9ccdbe1252050a7ddbd146dd425f4fb48251f378",
)

Enable the extra_action that captures the compilation commands in your project's .bazelrc:

build --experimental_action_listener=@bazel_compilation_database//:capture
# Optional: restrict usage of the listener by regex
# build --experimental_extra_action_filter=^//src(/|:)

This handy script will then collect the compilation commands into compile_commands.json:

#!/usr/bin/env bash

ACTION_DIRECTORY="$(bazel info output_path)/local-fastbuild/extra_actions/external/bazel_compilation_database/capture_action"
EXEC_DIRECTORY="$(bazel info execution_root)"
COMMAND_DB_FILE="$(bazel info workspace)/compile_commands.json"

bazel run @bazel_compilation_database//:collect -- "$ACTION_DIRECTORY" "$EXEC_DIRECTORY" "$COMMAND_DB_FILE"

If you saved this snippet in update_compilation_database.sh and made it executable, then running it after bazel build will update the compile_commands.json file in the root of your project, like so:

bazel build <your target> && ./update_compilation_database.sh

You may need to bazel clean your project before this works.