[clang-tidy] Add -extra-arg and -extra-arg-before to run-clang-tidy.py

[• ehsan]

Summary

These flags allow specifying extra arguments to the tool's command
line which don't appear in the compilation database.

[bkramer]

This looks useful to me.

[alexfh]

clang-tidy/tool/run-clang-tidy.py

80

Why arg[0] and not just arg?

[• ehsan]

clang-tidy/tool/run-clang-tidy.py

80

With nargs=1, extra_arg would be something like [['foo'], ['bar']] if -extra-arg foo -extra-arg bar is passed. But I realized that there is no good reason why I need nargs=1 since action='append' will make the arg parser consume one argument, so I'll remove that and simplify this to just arg.

clang-tidy/tool/run-clang-tidy.py

while not os.path.isfile(os.path.join(result, path)):
     if os.path.realpath(result) == '/':
       print 'Error: could not find compilation database.'
       sys.exit(1)
     result += '../'
   return os.path.realpath(result)
 
 
 def get_tidy_invocation(f, clang_tidy_binary, checks, tmpdir, build_path,
-                        header_filter):
+                        header_filter, extra_arg, extra_arg_before):
   """Gets a command line for clang-tidy."""
   start = [clang_tidy_binary]
   if header_filter is not None:
     start.append('-header-filter=' + header_filter)
   else:
     # Show warnings in all in-project headers by default.
     start.append('-header-filter=^' + build_path + '/.*')
   if checks:
     start.append('-checks=' + checks)
   if tmpdir is not None:
     start.append('-export-fixes')
     # Get a temporary file. We immediately close the handle so clang-tidy can
     # overwrite it.
     (handle, name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
     os.close(handle)
     start.append(name)
+  for arg in extra_arg:
+      start.append('-extra-arg=%s' % arg[0])
+  for arg in extra_arg_before:
+      start.append('-extra-arg-before=%s' % arg[0])
   start.append('-p=' + build_path)
   start.append(f)
   return start
 
 
 def apply_fixes(args, tmpdir):
   """Calls clang-apply-fixes on a given directory. Deletes the dir when done."""
   invocation = [args.clang_apply_replacements_binary]
   if args.format:
     invocation.append('-format')
   invocation.append(tmpdir)
   subprocess.call(invocation)
   shutil.rmtree(tmpdir)
 
 
 def run_tidy(args, tmpdir, build_path, queue):
   """Takes filenames out of queue and runs clang-tidy on them."""
   while True:
     name = queue.get()
     invocation = get_tidy_invocation(name, args.clang_tidy_binary, args.checks,
-                                     tmpdir, build_path, args.header_filter)
+                                     tmpdir, build_path, args.header_filter,
+                                     args.extra_arg, args.extra_arg_before)
     sys.stdout.write(' '.join(invocation) + '\n')
     subprocess.call(invocation)
     queue.task_done()
 
 
 def main():
   parser = argparse.ArgumentParser(description='Runs clang-tidy over all files '
                                    'in a compilation database. Requires '
parser.add_argument('-j', type=int, default=0,
                       help='number of tidy instances to be run in parallel.')
   parser.add_argument('files', nargs='*', default=['.*'],
                       help='files to be processed (regex on path)')
   parser.add_argument('-fix', action='store_true', help='apply fix-its')
   parser.add_argument('-format', action='store_true', help='Reformat code '
                       'after applying fixes')
   parser.add_argument('-p', dest='build_path',
                       help='Path used to read a compile command database.')
+  parser.add_argument('-extra-arg', dest='extra_arg',
+                      nargs=1, action='append', default=[],
+                      help='Additional argument to append to the compiler '
+                      'command line.')
+  parser.add_argument('-extra-arg-before', dest='extra_arg_before',
+                      nargs=1, action='append', default=[],
+                      help='Additional argument to prepend to the compiler '
+                      'command line.')
   args = parser.parse_args()
 
   db_path = 'compile_commands.json'
 
   if args.build_path is not None:
     build_path = args.build_path
   else:
     # Find our database