A simple compilation database (compile_commands.json) generator for Bazel.

• Implemented with aspects.
• Works with generated sources.
• The generated compile_commands.json contains info for headers.
• Supports C++ (not C) builds with rules_cc rules. Might work with custom C++ rules providing CcInfo, but see Limitations.

Synopsys

.bazelrc

common --registry=https://raw.githubusercontent.com/snailbaron/registry/main
common --registry=https://bcr.bazel.build

MODULE.bazel

bazel_dep(name = "snailbaron-compilation-database", version = "0.0.2")

BUILD.bazel

load("@snailbaron-compilation-database//:compdb.bzl", "compilation_database")

compilation_database(
    name = "compdb",
    srcs = [
        "//:target_a",
        "//:target_b",
        # ...
    ],
)

In the terminal:

bazel build //:compdb
ln -s bazel-bin/compile_commands.json .
ln -s $(bazel info output_base)/external .

Limitations

• C is not supported. -xc++ is currently forcefully inserted for every file.
• The aspect requires the CcInfo provider, propagates along the deps attribute, and looks into srcs and hdrs attributes to get the source files. This should work for the built-in/rules_cc rules, and for custom C++ rules if they are similar enough (also provide CcInfo and have deps/srcs/hdrs attributes with similar semantics).
• You must explicitly list all the targets you wish to generate the compilation database for. There is no way to generate it for //....
• You cannot customize the name or location of the genrated file: it's always named compile_commands.json and located in the directory corresponding to where compilation_database is defined. Also, if you work with multiple configurations, you might want to symlink bazel-out/<your-configuration> instead of bazel-bin.
• Only tested on Linux right now, and not very rigorously.