Tool to expand CMake unity builds for clangd support

README.md

deunify

This tool exands the compile_commands.json of unity build files generated by CMake to enable clangd support.

Without this, clangd doesn't know what to do with the compilation units.

Default file is compile_commands.json in the current working directory. Outputs to console by default. Use -i to update in-place.

To use:

deunify -i build/compile_commands.json
deunify -i # update file in the same directory

deunity

#!python3

import json
import argparse


def traverse(entry):
    with open(entry["file"]) as f:
        for line in f:
            if line.startswith('#include "/'):
                file = line.removeprefix('#include "').removesuffix(
                    '\n').removesuffix('"')
                output = file + ".o"
                command = entry["command"].replace(
                    entry["file"], file).replace(entry["output"], output)
                yield {
                    "directory": entry["directory"],
                    "command": command,
                    "file": file,
                    "output": file + ".o"
                }


def deunify(cc):
    return cc + [newentry for entry in cc for newentry in traverse(entry)]


def main():
    p = argparse.ArgumentParser()
    p.add_argument("file", nargs="?", default="compile_commands.json")
    p.add_argument("-i", "--inplace", action="store_true", help="Overwrite input file")
    args = p.parse_args()

    with open(args.file) as f:
        cc = json.load(f)
    res = deunify(cc)

    if args.inplace:
        with open(args.file, "w") as f:
            json.dump(res, f, indent=2)
    else:
        print(json.dumps(res, indent=2))


if __name__ == "__main__":
    main()