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

[• ehsan]

Summary

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

[• ehsan]

This is equivalent to https://reviews.llvm.org/D28334 for clang-tidy-diff.py.

[klimek]

lg

clang-tools-extra/trunk/clang-tidy/tool/clang-tidy-diff.py

parser.add_argument('-iregex', metavar='PATTERN', default=
                       '(case insensitive, overridden by -regex)')
 
   parser.add_argument('-fix', action='store_true', default=False,
                       help='apply suggested fixes')
   parser.add_argument('-checks',
                       help='checks filter, when not specified, use clang-tidy '
                       'default',
                       default='')
+  parser.add_argument('-extra-arg', dest='extra_arg',
+                      action='append', default=[],
+                      help='Additional argument to append to the compiler '
+                      'command line.')
+  parser.add_argument('-extra-arg-before', dest='extra_arg_before',
+                      action='append', default=[],
+                      help='Additional argument to prepend to the compiler '
+                      'command line.')
   clang_tidy_args = []
   argv = sys.argv[1:]
   if '--' in argv:
     clang_tidy_args.extend(argv[argv.index('--'):])
     argv = argv[:argv.index('--')]
 
   args = parser.parse_args(argv)
 
def main():
   # Run clang-tidy on files containing changes.
   command = [args.clang_tidy_binary]
   command.append('-line-filter=' + quote + line_filter_json + quote)
   if args.fix:
     command.append('-fix')
   if args.checks != '':
     command.append('-checks=' + quote + args.checks + quote)
   command.extend(lines_by_file.keys())
+  for arg in args.extra_arg:
+      command.append('-extra-arg=%s' % arg)
+  for arg in args.extra_arg_before:
+      command.append('-extra-arg-before=%s' % arg)
   command.extend(clang_tidy_args)
 
   sys.exit(subprocess.call(' '.join(command), shell=True))
 
 if __name__ == '__main__':
   main()