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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
16import sys
17
18_DEFAULT_OUTPUT = 'compile_commands.json'
19_DEFAULT_LOG_LEVEL = 'WARNING'
20
21_FILENAME_PATTERN = r'^\..*\.cmd$'
22_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$'
23_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
24# The tools/ directory adopts a different build system, and produces .cmd
25# files in a different format. Do not support it.
26_EXCLUDE_DIRS = ['.git', 'Documentation', 'include', 'tools']
27
28def parse_arguments():
29 """Sets up and parses command-line arguments.
30
31 Returns:
32 log_level: A logging level to filter log output.
33 directory: The work directory where the objects were built.
34 ar: Command used for parsing .a archives.
35 output: Where to write the compile-commands JSON file.
36 paths: The list of files/directories to handle to find .cmd files.
37 """
38 usage = 'Creates a compile_commands.json database from kernel .cmd files'
39 parser = argparse.ArgumentParser(description=usage)
40
41 directory_help = ('specify the output directory used for the kernel build '
42 '(defaults to the working directory)')
43 parser.add_argument('-d', '--directory', type=str, default='.',
44 help=directory_help)
45
46 output_help = ('path to the output command database (defaults to ' +
47 _DEFAULT_OUTPUT + ')')
48 parser.add_argument('-o', '--output', type=str, default=_DEFAULT_OUTPUT,
49 help=output_help)
50
51 log_level_help = ('the level of log messages to produce (defaults to ' +
52 _DEFAULT_LOG_LEVEL + ')')
53 parser.add_argument('--log_level', choices=_VALID_LOG_LEVELS,
54 default=_DEFAULT_LOG_LEVEL, help=log_level_help)
55
56 ar_help = 'command used for parsing .a archives'
57 parser.add_argument('-a', '--ar', type=str, default='llvm-ar', help=ar_help)
58
59 paths_help = ('directories to search or files to parse '
60 '(files should be *.o, *.a, or modules.order). '
61 'If nothing is specified, the current directory is searched')
62 parser.add_argument('paths', type=str, nargs='*', help=paths_help)
63
64 args = parser.parse_args()
65
66 return (args.log_level,
67 os.path.abspath(args.directory),
68 args.output,
69 args.ar,
70 args.paths if len(args.paths) > 0 else [args.directory])
71
72
73def cmdfiles_in_dir(directory):
74 """Generate the iterator of .cmd files found under the directory.
75
76 Walk under the given directory, and yield every .cmd file found.
77
78 Args:
79 directory: The directory to search for .cmd files.
80
81 Yields:
82 The path to a .cmd file.
83 """
84
85 filename_matcher = re.compile(_FILENAME_PATTERN)
86 exclude_dirs = [ os.path.join(directory, d) for d in _EXCLUDE_DIRS ]
87
88 for dirpath, dirnames, filenames in os.walk(directory, topdown=True):
89 # Prune unwanted directories.
90 if dirpath in exclude_dirs:
91 dirnames[:] = []
92 continue
93
94 for filename in filenames:
95 if filename_matcher.match(filename):
96 yield os.path.join(dirpath, filename)
97
98
99def to_cmdfile(path):
100 """Return the path of .cmd file used for the given build artifact
101
102 Args:
103 Path: file path
104
105 Returns:
106 The path to .cmd file
107 """
108 dir, base = os.path.split(path)
109 return os.path.join(dir, '.' + base + '.cmd')
110
111
112def cmdfiles_for_o(obj):
113 """Generate the iterator of .cmd files associated with the object
114
115 Yield the .cmd file used to build the given object
116
117 Args:
118 obj: The object path
119
120 Yields:
121 The path to .cmd file
122 """
123 yield to_cmdfile(obj)
124
125
126def cmdfiles_for_a(archive, ar):
127 """Generate the iterator of .cmd files associated with the archive.
128
129 Parse the given archive, and yield every .cmd file used to build it.
130
131 Args:
132 archive: The archive to parse
133
134 Yields:
135 The path to every .cmd file found
136 """
137 for obj in subprocess.check_output([ar, '-t', archive]).decode().split():
138 yield to_cmdfile(obj)
139
140
141def cmdfiles_for_modorder(modorder):
142 """Generate the iterator of .cmd files associated with the modules.order.
143
144 Parse the given modules.order, and yield every .cmd file used to build the
145 contained modules.
146
147 Args:
148 modorder: The modules.order file to parse
149
150 Yields:
151 The path to every .cmd file found
152 """
153 with open(modorder) as f:
154 for line in f:
155 ko = line.rstrip()
156 base, ext = os.path.splitext(ko)
157 if ext != '.ko':
158 sys.exit('{}: module path must end with .ko'.format(ko))
159 mod = base + '.mod'
160 # The first line of *.mod lists the objects that compose the module.
161 with open(mod) as m:
162 for obj in m.readline().split():
163 yield to_cmdfile(obj)
164
165
166def process_line(root_directory, command_prefix, file_path):
167 """Extracts information from a .cmd line and creates an entry from it.
168
169 Args:
170 root_directory: The directory that was searched for .cmd files. Usually
171 used directly in the "directory" entry in compile_commands.json.
172 command_prefix: The extracted command line, up to the last element.
173 file_path: The .c file from the end of the extracted command.
174 Usually relative to root_directory, but sometimes absolute.
175
176 Returns:
177 An entry to append to compile_commands.
178
179 Raises:
180 ValueError: Could not find the extracted file based on file_path and
181 root_directory or file_directory.
182 """
183 # The .cmd files are intended to be included directly by Make, so they
184 # escape the pound sign '#', either as '\#' or '$(pound)' (depending on the
185 # kernel version). The compile_commands.json file is not interepreted
186 # by Make, so this code replaces the escaped version with '#'.
187 prefix = command_prefix.replace('\#', '#').replace('$(pound)', '#')
188
189 # Use os.path.abspath() to normalize the path resolving '.' and '..' .
190 abs_path = os.path.abspath(os.path.join(root_directory, file_path))
191 if not os.path.exists(abs_path):
192 raise ValueError('File %s not found' % abs_path)
193 return {
194 'directory': root_directory,
195 'file': abs_path,
196 'command': prefix + file_path,
197 }
198
199
200def main():
201 """Walks through the directory and finds and parses .cmd files."""
202 log_level, directory, output, ar, paths = parse_arguments()
203
204 level = getattr(logging, log_level)
205 logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
206
207 line_matcher = re.compile(_LINE_PATTERN)
208
209 compile_commands = []
210
211 for path in paths:
212 # If 'path' is a directory, handle all .cmd files under it.
213 # Otherwise, handle .cmd files associated with the file.
214 # Most of built-in objects are linked via archives (built-in.a or lib.a)
215 # but some objects are linked to vmlinux directly.
216 # Modules are listed in modules.order.
217 if os.path.isdir(path):
218 cmdfiles = cmdfiles_in_dir(path)
219 elif path.endswith('.o'):
220 cmdfiles = cmdfiles_for_o(path)
221 elif path.endswith('.a'):
222 cmdfiles = cmdfiles_for_a(path, ar)
223 elif path.endswith('modules.order'):
224 cmdfiles = cmdfiles_for_modorder(path)
225 else:
226 sys.exit('{}: unknown file type'.format(path))
227
228 for cmdfile in cmdfiles:
229 with open(cmdfile, 'rt') as f:
230 result = line_matcher.match(f.readline())
231 if result:
232 try:
233 entry = process_line(directory, result.group(1),
234 result.group(2))
235 compile_commands.append(entry)
236 except ValueError as err:
237 logging.info('Could not add line from %s: %s',
238 cmdfile, err)
239
240 with open(output, 'wt') as f:
241 json.dump(compile_commands, f, indent=2, sort_keys=True)
242
243
244if __name__ == '__main__':
245 main()