xref: /llvm-project/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py (revision f8b7269f983aad40730ad845dae5c3d2f43093b0) 
1#!/usr/bin/env python
2#
3#===- clang-tidy-diff.py - ClangTidy Diff Checker ------------*- python -*--===#
4#
5# Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
6# See https://llvm.org/LICENSE.txt for license information.
7# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
8#
9#===------------------------------------------------------------------------===#
10
11r"""
12ClangTidy Diff Checker
13======================
14
15This script reads input from a unified diff, runs clang-tidy on all changed
16files and outputs clang-tidy warnings in changed lines only. This is useful to
17detect clang-tidy regressions in the lines touched by a specific patch.
18Example usage for git/svn users:
19
20  git diff -U0 HEAD^ | clang-tidy-diff.py -p1
21  svn diff --diff-cmd=diff -x-U0 | \
22      clang-tidy-diff.py -fix -checks=-*,modernize-use-override
23
24"""
25
26import argparse
27import glob
28import json
29import multiprocessing
30import os
31import re
32import shutil
33import subprocess
34import sys
35import tempfile
36import threading
37import traceback
38
39try:
40  import yaml
41except ImportError:
42  yaml = None
43
44is_py2 = sys.version[0] == '2'
45
46if is_py2:
47    import Queue as queue
48else:
49    import queue as queue
50
51
52def run_tidy(task_queue, lock, timeout):
53  watchdog = None
54  while True:
55    command = task_queue.get()
56    try:
57      proc = subprocess.Popen(command,
58                              stdout=subprocess.PIPE,
59                              stderr=subprocess.PIPE)
60
61      if timeout is not None:
62        watchdog = threading.Timer(timeout, proc.kill)
63        watchdog.start()
64
65      stdout, stderr = proc.communicate()
66
67      with lock:
68        sys.stdout.write(stdout.decode('utf-8') + '\n')
69        sys.stdout.flush()
70        if stderr:
71          sys.stderr.write(stderr.decode('utf-8') + '\n')
72          sys.stderr.flush()
73    except Exception as e:
74      with lock:
75        sys.stderr.write('Failed: ' + str(e) + ': '.join(command) + '\n')
76    finally:
77      with lock:
78        if (not timeout is None) and (not watchdog is None):
79          if not watchdog.is_alive():
80              sys.stderr.write('Terminated by timeout: ' +
81                               ' '.join(command) + '\n')
82          watchdog.cancel()
83      task_queue.task_done()
84
85
86def start_workers(max_tasks, tidy_caller, task_queue, lock, timeout):
87  for _ in range(max_tasks):
88    t = threading.Thread(target=tidy_caller, args=(task_queue, lock, timeout))
89    t.daemon = True
90    t.start()
91
92def merge_replacement_files(tmpdir, mergefile):
93  """Merge all replacement files in a directory into a single file"""
94  # The fixes suggested by clang-tidy >= 4.0.0 are given under
95  # the top level key 'Diagnostics' in the output yaml files
96  mergekey = "Diagnostics"
97  merged = []
98  for replacefile in glob.iglob(os.path.join(tmpdir, '*.yaml')):
99    content = yaml.safe_load(open(replacefile, 'r'))
100    if not content:
101      continue # Skip empty files.
102    merged.extend(content.get(mergekey, []))
103
104  if merged:
105    # MainSourceFile: The key is required by the definition inside
106    # include/clang/Tooling/ReplacementsYaml.h, but the value
107    # is actually never used inside clang-apply-replacements,
108    # so we set it to '' here.
109    output = { 'MainSourceFile': '', mergekey: merged }
110    with open(mergefile, 'w') as out:
111      yaml.safe_dump(output, out)
112  else:
113    # Empty the file:
114    open(mergefile, 'w').close()
115
116
117def main():
118  parser = argparse.ArgumentParser(description=
119                                   'Run clang-tidy against changed files, and '
120                                   'output diagnostics only for modified '
121                                   'lines.')
122  parser.add_argument('-clang-tidy-binary', metavar='PATH',
123                      default='clang-tidy',
124                      help='path to clang-tidy binary')
125  parser.add_argument('-p', metavar='NUM', default=0,
126                      help='strip the smallest prefix containing P slashes')
127  parser.add_argument('-regex', metavar='PATTERN', default=None,
128                      help='custom pattern selecting file paths to check '
129                      '(case sensitive, overrides -iregex)')
130  parser.add_argument('-iregex', metavar='PATTERN', default=
131                      r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hpp|m|mm|inc)',
132                      help='custom pattern selecting file paths to check '
133                      '(case insensitive, overridden by -regex)')
134  parser.add_argument('-j', type=int, default=1,
135                      help='number of tidy instances to be run in parallel.')
136  parser.add_argument('-timeout', type=int, default=None,
137                      help='timeout per each file in seconds.')
138  parser.add_argument('-fix', action='store_true', default=False,
139                      help='apply suggested fixes')
140  parser.add_argument('-checks',
141                      help='checks filter, when not specified, use clang-tidy '
142                      'default',
143                      default='')
144  parser.add_argument('-path', dest='build_path',
145                      help='Path used to read a compile command database.')
146  if yaml:
147    parser.add_argument('-export-fixes', metavar='FILE', dest='export_fixes',
148                        help='Create a yaml file to store suggested fixes in, '
149                        'which can be applied with clang-apply-replacements.')
150  parser.add_argument('-extra-arg', dest='extra_arg',
151                      action='append', default=[],
152                      help='Additional argument to append to the compiler '
153                      'command line.')
154  parser.add_argument('-extra-arg-before', dest='extra_arg_before',
155                      action='append', default=[],
156                      help='Additional argument to prepend to the compiler '
157                      'command line.')
158  parser.add_argument('-quiet', action='store_true', default=False,
159                      help='Run clang-tidy in quiet mode')
160  clang_tidy_args = []
161  argv = sys.argv[1:]
162  if '--' in argv:
163    clang_tidy_args.extend(argv[argv.index('--'):])
164    argv = argv[:argv.index('--')]
165
166  args = parser.parse_args(argv)
167
168  # Extract changed lines for each file.
169  filename = None
170  lines_by_file = {}
171  for line in sys.stdin:
172    match = re.search('^\+\+\+\ \"?(.*?/){%s}([^ \t\n\"]*)' % args.p, line)
173    if match:
174      filename = match.group(2)
175    if filename is None:
176      continue
177
178    if args.regex is not None:
179      if not re.match('^%s$' % args.regex, filename):
180        continue
181    else:
182      if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
183        continue
184
185    match = re.search('^@@.*\+(\d+)(,(\d+))?', line)
186    if match:
187      start_line = int(match.group(1))
188      line_count = 1
189      if match.group(3):
190        line_count = int(match.group(3))
191      if line_count == 0:
192        continue
193      end_line = start_line + line_count - 1
194      lines_by_file.setdefault(filename, []).append([start_line, end_line])
195
196  if not any(lines_by_file):
197    print("No relevant changes found.")
198    sys.exit(0)
199
200  max_task_count = args.j
201  if max_task_count == 0:
202      max_task_count = multiprocessing.cpu_count()
203  max_task_count = min(len(lines_by_file), max_task_count)
204
205  tmpdir = None
206  if yaml and args.export_fixes:
207    tmpdir = tempfile.mkdtemp()
208
209  # Tasks for clang-tidy.
210  task_queue = queue.Queue(max_task_count)
211  # A lock for console output.
212  lock = threading.Lock()
213
214  # Run a pool of clang-tidy workers.
215  start_workers(max_task_count, run_tidy, task_queue, lock, args.timeout)
216
217  # Form the common args list.
218  common_clang_tidy_args = []
219  if args.fix:
220    common_clang_tidy_args.append('-fix')
221  if args.checks != '':
222    common_clang_tidy_args.append('-checks=' + args.checks)
223  if args.quiet:
224    common_clang_tidy_args.append('-quiet')
225  if args.build_path is not None:
226    common_clang_tidy_args.append('-p=%s' % args.build_path)
227  for arg in args.extra_arg:
228    common_clang_tidy_args.append('-extra-arg=%s' % arg)
229  for arg in args.extra_arg_before:
230    common_clang_tidy_args.append('-extra-arg-before=%s' % arg)
231
232  for name in lines_by_file:
233    line_filter_json = json.dumps(
234      [{"name": name, "lines": lines_by_file[name]}],
235      separators=(',', ':'))
236
237    # Run clang-tidy on files containing changes.
238    command = [args.clang_tidy_binary]
239    command.append('-line-filter=' + line_filter_json)
240    if yaml and args.export_fixes:
241      # Get a temporary file. We immediately close the handle so clang-tidy can
242      # overwrite it.
243      (handle, tmp_name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
244      os.close(handle)
245      command.append('-export-fixes=' + tmp_name)
246    command.extend(common_clang_tidy_args)
247    command.append(name)
248    command.extend(clang_tidy_args)
249
250    task_queue.put(command)
251
252  # Wait for all threads to be done.
253  task_queue.join()
254
255  if yaml and args.export_fixes:
256    print('Writing fixes to ' + args.export_fixes + ' ...')
257    try:
258      merge_replacement_files(tmpdir, args.export_fixes)
259    except:
260      sys.stderr.write('Error exporting fixes.\n')
261      traceback.print_exc()
262
263  if tmpdir:
264    shutil.rmtree(tmpdir)
265
266
267if __name__ == '__main__':
268  main()
269