xref: /llvm-project/clang-tools-extra/clang-tidy/tool/clang-tidy-diff.py (revision 968d293063bc008ff93ff8fcf363039ce61574a2) 
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 or 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
92
93def merge_replacement_files(tmpdir, mergefile):
94  """Merge all replacement files in a directory into a single file"""
95  # The fixes suggested by clang-tidy >= 4.0.0 are given under
96  # the top level key 'Diagnostics' in the output yaml files
97  mergekey = "Diagnostics"
98  merged = []
99  for replacefile in glob.iglob(os.path.join(tmpdir, '*.yaml')):
100    content = yaml.safe_load(open(replacefile, 'r'))
101    if not content:
102      continue # Skip empty files.
103    merged.extend(content.get(mergekey, []))
104
105  if merged:
106    # MainSourceFile: The key is required by the definition inside
107    # include/clang/Tooling/ReplacementsYaml.h, but the value
108    # is actually never used inside clang-apply-replacements,
109    # so we set it to '' here.
110    output = {'MainSourceFile': '', mergekey: merged}
111    with open(mergefile, 'w') as out:
112      yaml.safe_dump(output, out)
113  else:
114    # Empty the file:
115    open(mergefile, 'w').close()
116
117
118def main():
119  parser = argparse.ArgumentParser(description=
120                                   'Run clang-tidy against changed files, and '
121                                   'output diagnostics only for modified '
122                                   'lines.')
123  parser.add_argument('-clang-tidy-binary', metavar='PATH',
124                      default='clang-tidy',
125                      help='path to clang-tidy binary')
126  parser.add_argument('-p', metavar='NUM', default=0,
127                      help='strip the smallest prefix containing P slashes')
128  parser.add_argument('-regex', metavar='PATTERN', default=None,
129                      help='custom pattern selecting file paths to check '
130                      '(case sensitive, overrides -iregex)')
131  parser.add_argument('-iregex', metavar='PATTERN', default=
132                      r'.*\.(cpp|cc|c\+\+|cxx|c|cl|h|hpp|m|mm|inc)',
133                      help='custom pattern selecting file paths to check '
134                      '(case insensitive, overridden by -regex)')
135  parser.add_argument('-j', type=int, default=1,
136                      help='number of tidy instances to be run in parallel.')
137  parser.add_argument('-timeout', type=int, default=None,
138                      help='timeout per each file in seconds.')
139  parser.add_argument('-fix', action='store_true', default=False,
140                      help='apply suggested fixes')
141  parser.add_argument('-checks',
142                      help='checks filter, when not specified, use clang-tidy '
143                      'default',
144                      default='')
145  parser.add_argument('-path', dest='build_path',
146                      help='Path used to read a compile command database.')
147  if yaml:
148    parser.add_argument('-export-fixes', metavar='FILE', dest='export_fixes',
149                        help='Create a yaml file to store suggested fixes in, '
150                        'which can be applied with clang-apply-replacements.')
151  parser.add_argument('-extra-arg', dest='extra_arg',
152                      action='append', default=[],
153                      help='Additional argument to append to the compiler '
154                      'command line.')
155  parser.add_argument('-extra-arg-before', dest='extra_arg_before',
156                      action='append', default=[],
157                      help='Additional argument to prepend to the compiler '
158                      'command line.')
159  parser.add_argument('-quiet', action='store_true', default=False,
160                      help='Run clang-tidy in quiet mode')
161  clang_tidy_args = []
162  argv = sys.argv[1:]
163  if '--' in argv:
164    clang_tidy_args.extend(argv[argv.index('--'):])
165    argv = argv[:argv.index('--')]
166
167  args = parser.parse_args(argv)
168
169  # Extract changed lines for each file.
170  filename = None
171  lines_by_file = {}
172  for line in sys.stdin:
173    match = re.search('^\+\+\+\ \"?(.*?/){%s}([^ \t\n\"]*)' % args.p, line)
174    if match:
175      filename = match.group(2)
176    if filename is None:
177      continue
178
179    if args.regex is not None:
180      if not re.match('^%s$' % args.regex, filename):
181        continue
182    else:
183      if not re.match('^%s$' % args.iregex, filename, re.IGNORECASE):
184        continue
185
186    match = re.search('^@@.*\+(\d+)(,(\d+))?', line)
187    if match:
188      start_line = int(match.group(1))
189      line_count = 1
190      if match.group(3):
191        line_count = int(match.group(3))
192      if line_count == 0:
193        continue
194      end_line = start_line + line_count - 1
195      lines_by_file.setdefault(filename, []).append([start_line, end_line])
196
197  if not any(lines_by_file):
198    print("No relevant changes found.")
199    sys.exit(0)
200
201  max_task_count = args.j
202  if max_task_count == 0:
203      max_task_count = multiprocessing.cpu_count()
204  max_task_count = min(len(lines_by_file), max_task_count)
205
206  tmpdir = None
207  if yaml and args.export_fixes:
208    tmpdir = tempfile.mkdtemp()
209
210  # Tasks for clang-tidy.
211  task_queue = queue.Queue(max_task_count)
212  # A lock for console output.
213  lock = threading.Lock()
214
215  # Run a pool of clang-tidy workers.
216  start_workers(max_task_count, run_tidy, task_queue, lock, args.timeout)
217
218  # Form the common args list.
219  common_clang_tidy_args = []
220  if args.fix:
221    common_clang_tidy_args.append('-fix')
222  if args.checks != '':
223    common_clang_tidy_args.append('-checks=' + args.checks)
224  if args.quiet:
225    common_clang_tidy_args.append('-quiet')
226  if args.build_path is not None:
227    common_clang_tidy_args.append('-p=%s' % args.build_path)
228  for arg in args.extra_arg:
229    common_clang_tidy_args.append('-extra-arg=%s' % arg)
230  for arg in args.extra_arg_before:
231    common_clang_tidy_args.append('-extra-arg-before=%s' % arg)
232
233  for name in lines_by_file:
234    line_filter_json = json.dumps(
235      [{"name": name, "lines": lines_by_file[name]}],
236      separators=(',', ':'))
237
238    # Run clang-tidy on files containing changes.
239    command = [args.clang_tidy_binary]
240    command.append('-line-filter=' + line_filter_json)
241    if yaml and args.export_fixes:
242      # Get a temporary file. We immediately close the handle so clang-tidy can
243      # overwrite it.
244      (handle, tmp_name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
245      os.close(handle)
246      command.append('-export-fixes=' + tmp_name)
247    command.extend(common_clang_tidy_args)
248    command.append(name)
249    command.extend(clang_tidy_args)
250
251    task_queue.put(command)
252
253  # Wait for all threads to be done.
254  task_queue.join()
255
256  if yaml and args.export_fixes:
257    print('Writing fixes to ' + args.export_fixes + ' ...')
258    try:
259      merge_replacement_files(tmpdir, args.export_fixes)
260    except:
261      sys.stderr.write('Error exporting fixes.\n')
262      traceback.print_exc()
263
264  if tmpdir:
265    shutil.rmtree(tmpdir)
266
267
268if __name__ == '__main__':
269  main()
270