2 # SPDX-License-Identifier: GPL-2.0
4 # Copyright (C) Google LLC, 2018
6 # Author: Tom Roeder <tmroeder@google.com>
8 """A tool for generating compile_commands.json in the Linux kernel."""
16 _DEFAULT_OUTPUT = 'compile_commands.json'
17 _DEFAULT_LOG_LEVEL = 'WARNING'
19 _FILENAME_PATTERN = r'^\..*\.cmd$'
20 _LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$'
21 _VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
23 # A kernel build generally has over 2000 entries in its compile_commands.json
24 # database. If this code finds 300 or fewer, then warn the user that they might
25 # not have all the .cmd files, and they might need to compile the kernel.
26 _LOW_COUNT_THRESHOLD = 300
29 def parse_arguments():
30 """Sets up and parses command-line arguments.
33 log_level: A logging level to filter log output.
34 directory: The work directory where the objects were built.
35 output: Where to write the compile-commands JSON file.
37 usage = 'Creates a compile_commands.json database from kernel .cmd files'
38 parser = argparse.ArgumentParser(description=usage)
40 directory_help = ('specify the output directory used for the kernel build '
41 '(defaults to the working directory)')
42 parser.add_argument('-d', '--directory', type=str, default='.',
45 output_help = ('path to the output command database (defaults to ' +
46 _DEFAULT_OUTPUT + ')')
47 parser.add_argument('-o', '--output', type=str, default=_DEFAULT_OUTPUT,
50 log_level_help = ('the level of log messages to produce (defaults to ' +
51 _DEFAULT_LOG_LEVEL + ')')
52 parser.add_argument('--log_level', choices=_VALID_LOG_LEVELS,
53 default=_DEFAULT_LOG_LEVEL, help=log_level_help)
55 args = parser.parse_args()
57 return (args.log_level,
58 os.path.abspath(args.directory),
62 def process_line(root_directory, command_prefix, file_path):
63 """Extracts information from a .cmd line and creates an entry from it.
66 root_directory: The directory that was searched for .cmd files. Usually
67 used directly in the "directory" entry in compile_commands.json.
68 command_prefix: The extracted command line, up to the last element.
69 file_path: The .c file from the end of the extracted command.
70 Usually relative to root_directory, but sometimes absolute.
73 An entry to append to compile_commands.
76 ValueError: Could not find the extracted file based on file_path and
77 root_directory or file_directory.
79 # The .cmd files are intended to be included directly by Make, so they
80 # escape the pound sign '#', either as '\#' or '$(pound)' (depending on the
81 # kernel version). The compile_commands.json file is not interepreted
82 # by Make, so this code replaces the escaped version with '#'.
83 prefix = command_prefix.replace('\#', '#').replace('$(pound)', '#')
85 # Use os.path.abspath() to normalize the path resolving '.' and '..' .
86 abs_path = os.path.abspath(os.path.join(root_directory, file_path))
87 if not os.path.exists(abs_path):
88 raise ValueError('File %s not found' % abs_path)
90 'directory': root_directory,
92 'command': prefix + file_path,
97 """Walks through the directory and finds and parses .cmd files."""
98 log_level, directory, output = parse_arguments()
100 level = getattr(logging, log_level)
101 logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
103 filename_matcher = re.compile(_FILENAME_PATTERN)
104 line_matcher = re.compile(_LINE_PATTERN)
106 compile_commands = []
107 for dirpath, _, filenames in os.walk(directory):
108 for filename in filenames:
109 if not filename_matcher.match(filename):
111 filepath = os.path.join(dirpath, filename)
113 with open(filepath, 'rt') as f:
114 result = line_matcher.match(f.readline())
117 entry = process_line(directory,
118 result.group(1), result.group(2))
119 compile_commands.append(entry)
120 except ValueError as err:
121 logging.info('Could not add line from %s: %s',
124 with open(output, 'wt') as f:
125 json.dump(compile_commands, f, indent=2, sort_keys=True)
127 count = len(compile_commands)
128 if count < _LOW_COUNT_THRESHOLD:
130 'Found %s entries. Have you compiled the kernel?', count)
133 if __name__ == '__main__':