tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1#!/usr/bin/env python3
2# SPDX-License-Identifier: GPL-2.0
3#
4# Copyright (C) Google LLC, 2018
5#
6# Author: Tom Roeder <tmroeder@google.com>
7#
8"""A tool for generating compile_commands.json in the Linux kernel."""
9
10import argparse
11import json
12import logging
13import os
14import re
15import subprocess
16
17_DEFAULT_OUTPUT = 'compile_commands.json'
18_DEFAULT_LOG_LEVEL = 'WARNING'
19
20_FILENAME_PATTERN = r'^\..*\.cmd$'
21_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$'
22_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
23# The tools/ directory adopts a different build system, and produces .cmd
24# files in a different format. Do not support it.
25_EXCLUDE_DIRS = ['.git', 'Documentation', 'include', 'tools']
26
27def parse_arguments():
28 """Sets up and parses command-line arguments.
29
30 Returns:
31 log_level: A logging level to filter log output.
32 directory: The work directory where the objects were built.
33 ar: Command used for parsing .a archives.
34 output: Where to write the compile-commands JSON file.
35 paths: The list of files/directories to handle to find .cmd files.
36 """
37 usage = 'Creates a compile_commands.json database from kernel .cmd files'
38 parser = argparse.ArgumentParser(description=usage)
39
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='.',
43 help=directory_help)
44
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,
48 help=output_help)
49
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)
54
55 ar_help = 'command used for parsing .a archives'
56 parser.add_argument('-a', '--ar', type=str, default='llvm-ar', help=ar_help)
57
58 paths_help = ('directories to search or files to parse '
59 '(files should be *.o, *.a, or modules.order). '
60 'If nothing is specified, the current directory is searched')
61 parser.add_argument('paths', type=str, nargs='*', help=paths_help)
62
63 args = parser.parse_args()
64
65 return (args.log_level,
66 os.path.abspath(args.directory),
67 args.output,
68 args.ar,
69 args.paths if len(args.paths) > 0 else [args.directory])
70
71
72def cmdfiles_in_dir(directory):
73 """Generate the iterator of .cmd files found under the directory.
74
75 Walk under the given directory, and yield every .cmd file found.
76
77 Args:
78 directory: The directory to search for .cmd files.
79
80 Yields:
81 The path to a .cmd file.
82 """
83
84 filename_matcher = re.compile(_FILENAME_PATTERN)
85 exclude_dirs = [ os.path.join(directory, d) for d in _EXCLUDE_DIRS ]
86
87 for dirpath, dirnames, filenames in os.walk(directory, topdown=True):
88 # Prune unwanted directories.
89 if dirpath in exclude_dirs:
90 dirnames[:] = []
91 continue
92
93 for filename in filenames:
94 if filename_matcher.match(filename):
95 yield os.path.join(dirpath, filename)
96
97
98def to_cmdfile(path):
99 """Return the path of .cmd file used for the given build artifact
100
101 Args:
102 Path: file path
103
104 Returns:
105 The path to .cmd file
106 """
107 dir, base = os.path.split(path)
108 return os.path.join(dir, '.' + base + '.cmd')
109
110
111def cmdfiles_for_o(obj):
112 """Generate the iterator of .cmd files associated with the object
113
114 Yield the .cmd file used to build the given object
115
116 Args:
117 obj: The object path
118
119 Yields:
120 The path to .cmd file
121 """
122 yield to_cmdfile(obj)
123
124
125def cmdfiles_for_a(archive, ar):
126 """Generate the iterator of .cmd files associated with the archive.
127
128 Parse the given archive, and yield every .cmd file used to build it.
129
130 Args:
131 archive: The archive to parse
132
133 Yields:
134 The path to every .cmd file found
135 """
136 for obj in subprocess.check_output([ar, '-t', archive]).decode().split():
137 yield to_cmdfile(obj)
138
139
140def cmdfiles_for_modorder(modorder):
141 """Generate the iterator of .cmd files associated with the modules.order.
142
143 Parse the given modules.order, and yield every .cmd file used to build the
144 contained modules.
145
146 Args:
147 modorder: The modules.order file to parse
148
149 Yields:
150 The path to every .cmd file found
151 """
152 with open(modorder) as f:
153 for line in f:
154 ko = line.rstrip()
155 base, ext = os.path.splitext(ko)
156 if ext != '.ko':
157 sys.exit('{}: module path must end with .ko'.format(ko))
158 mod = base + '.mod'
159 # The first line of *.mod lists the objects that compose the module.
160 with open(mod) as m:
161 for obj in m.readline().split():
162 yield to_cmdfile(obj)
163
164
165def process_line(root_directory, command_prefix, file_path):
166 """Extracts information from a .cmd line and creates an entry from it.
167
168 Args:
169 root_directory: The directory that was searched for .cmd files. Usually
170 used directly in the "directory" entry in compile_commands.json.
171 command_prefix: The extracted command line, up to the last element.
172 file_path: The .c file from the end of the extracted command.
173 Usually relative to root_directory, but sometimes absolute.
174
175 Returns:
176 An entry to append to compile_commands.
177
178 Raises:
179 ValueError: Could not find the extracted file based on file_path and
180 root_directory or file_directory.
181 """
182 # The .cmd files are intended to be included directly by Make, so they
183 # escape the pound sign '#', either as '\#' or '$(pound)' (depending on the
184 # kernel version). The compile_commands.json file is not interepreted
185 # by Make, so this code replaces the escaped version with '#'.
186 prefix = command_prefix.replace('\#', '#').replace('$(pound)', '#')
187
188 # Use os.path.abspath() to normalize the path resolving '.' and '..' .
189 abs_path = os.path.abspath(os.path.join(root_directory, file_path))
190 if not os.path.exists(abs_path):
191 raise ValueError('File %s not found' % abs_path)
192 return {
193 'directory': root_directory,
194 'file': abs_path,
195 'command': prefix + file_path,
196 }
197
198
199def main():
200 """Walks through the directory and finds and parses .cmd files."""
201 log_level, directory, output, ar, paths = parse_arguments()
202
203 level = getattr(logging, log_level)
204 logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
205
206 line_matcher = re.compile(_LINE_PATTERN)
207
208 compile_commands = []
209
210 for path in paths:
211 # If 'path' is a directory, handle all .cmd files under it.
212 # Otherwise, handle .cmd files associated with the file.
213 # Most of built-in objects are linked via archives (built-in.a or lib.a)
214 # but some objects are linked to vmlinux directly.
215 # Modules are listed in modules.order.
216 if os.path.isdir(path):
217 cmdfiles = cmdfiles_in_dir(path)
218 elif path.endswith('.o'):
219 cmdfiles = cmdfiles_for_o(path)
220 elif path.endswith('.a'):
221 cmdfiles = cmdfiles_for_a(path, ar)
222 elif path.endswith('modules.order'):
223 cmdfiles = cmdfiles_for_modorder(path)
224 else:
225 sys.exit('{}: unknown file type'.format(path))
226
227 for cmdfile in cmdfiles:
228 with open(cmdfile, 'rt') as f:
229 result = line_matcher.match(f.readline())
230 if result:
231 try:
232 entry = process_line(directory, result.group(1),
233 result.group(2))
234 compile_commands.append(entry)
235 except ValueError as err:
236 logging.info('Could not add line from %s: %s',
237 cmdfile, err)
238
239 with open(output, 'wt') as f:
240 json.dump(compile_commands, f, indent=2, sort_keys=True)
241
242
243if __name__ == '__main__':
244 main()