#!/usr/bin/env python
# SPDX-License-Identifier: GPL-2.0
#
# Copyright (C) Google LLC, 2018
#
# Author: Tom Roeder <tmroeder@google.com>
#
"""A tool for generating compile_commands.json in the Linux kernel."""
import argparse
import json
import logging
import os
import re
_DEFAULT_OUTPUT = 'compile_commands.json'
_DEFAULT_LOG_LEVEL = 'WARNING'
_FILENAME_PATTERN = r'^\..*\.cmd$'
_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$'
_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
# A kernel build generally has over 2000 entries in its compile_commands.json
# database. If this code finds 300 or fewer, then warn the user that they might
# not have all the .cmd files, and they might need to compile the kernel.
_LOW_COUNT_THRESHOLD = 300
def parse_arguments():
"""Sets up and parses command-line arguments.
Returns:
log_level: A logging level to filter log output.
directory: The work directory where the objects were built.
output: Where to write the compile-commands JSON file.
"""
usage = 'Creates a compile_commands.json database from kernel .cmd files'
parser = argparse.ArgumentParser(description=usage)
directory_help = ('specify the output directory used for the kernel build '
'(defaults to the working directory)')
parser.add_argument('-d', '--directory', type=str, default='.',
help=directory_help)
output_help = ('path to the output command database (defaults to ' +
_DEFAULT_OUTPUT + ')')
parser.add_argument('-o', '--output', type=str, default=_DEFAULT_OUTPUT,
help=output_help)
log_level_help = ('the level of log messages to produce (defaults to ' +
_DEFAULT_LOG_LEVEL + ')')
parser.add_argument('--log_level', choices=_VALID_LOG_LEVELS,
default=_DEFAULT_LOG_LEVEL, help=log_level_help)
args = parser.parse_args()
return (args.log_level,
os.path.abspath(args.directory),
args.output)
def process_line(root_directory, command_prefix, file_path):
"""Extracts information from a .cmd line and creates an entry from it.
Args:
root_directory: The directory that was searched for .cmd files. Usually
used directly in the "directory" entry in compile_commands.json.
command_prefix: The extracted command line, up to the last element.
file_path: The .c file from the end of the extracted command.
Usually relative to root_directory, but sometimes absolute.
Returns:
An entry to append to compile_commands.
Raises:
ValueError: Could not find the extracted file based on file_path and
root_directory or file_directory.
"""
# The .cmd files are intended to be included directly by Make, so they
# escape the pound sign '#', either as '\#' or '$(pound)' (depending on the
# kernel version). The compile_commands.json file is not interepreted
# by Make, so this code replaces the escaped version with '#'.
prefix = command_prefix.replace('\#', '#').replace('$(pound)', '#')
# Use os.path.abspath() to normalize the path resolving '.' and '..' .
abs_path = os.path.abspath(os.path.join(root_directory, file_path))
if not os.path.exists(abs_path):
raise ValueError('File %s not found' % abs_path)
return {
'directory': root_directory,
'file': abs_path,
'command': prefix + file_path,
}
def main():
"""Walks through the directory and finds and parses .cmd files."""
log_level, directory, output = parse_arguments()
level = getattr(logging, log_level)
logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
filename_matcher = re.compile(_FILENAME_PATTERN)
line_matcher = re.compile(_LINE_PATTERN)
compile_commands = []
for dirpath, _, filenames in os.walk(directory):
for filename in filenames:
if not filename_matcher.match(filename):
continue
filepath = os.path.join(dirpath, filename)
with open(filepath, 'rt') as f:
result = line_matcher.match(f.readline())
if result:
try:
entry = process_line(directory,
result.group(1), result.group(2))
compile_commands.append(entry)
except ValueError as err:
logging.info('Could not add line from %s: %s',
filepath, err)
with open(output, 'wt') as f:
json.dump(compile_commands, f, indent=2, sort_keys=True)
count = len(compile_commands)
if count < _LOW_COUNT_THRESHOLD:
logging.warning(
'Found %s entries. Have you compiled the kernel?', count)
if __name__ == '__main__':
main()
