Script to apply fixits generated by Clang.

Though clang has a mode to automatically apply fixits and recompile with
the -Xclang -fixit-recompile flag, this doesn't work well with parallel
invocations of clang.

BUG=557422
R=thakis@chromium.org

Review URL: https://codereview.chromium.org/1538703002 .

Cr-Commit-Position: refs/heads/master@{#365957}

1 files changed, 88 insertions, 0 deletions

diff --git a/tools/clang/scripts/apply_fixits.py b/tools/clang/scripts/apply_fixits.py
new file mode 100755
index 0000000..6387f2d
--- /dev/null
+++ b/tools/clang/scripts/apply_fixits.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env/python
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Script to apply fixits generated by clang. This is to work around the fact
+# that clang's -Xclang -fixit-recompile flag, which automatically applies fixits
+# and recompiles, doesn't work well with parallel invocations of clang.
+#
+# Usage:
+# 1. Enable parseable fixits and disable warnings as errors. Instructions for
+#    doing this vary based on the build environment, but for GN, warnings as
+#    errors can be disabled by setting treat_warnings_as_errors = false
+#    Enabling parseable fixits requires editing build/config/compiler/BUILD.gn
+#    and adding `-fdiagnostics-parseable-fixits` to cflags.
+# 2. Build everything and capture the output:
+#      ninja -C <build_directory> &> generated-fixits
+# 3. Apply the fixits with this script:
+#      python apply_fixits.py[ <build_directory>] < generated-fixits
+#    <build_directory> is optional and only required if your build directory is
+#    a non-standard location.
+
+import argparse
+import collections
+import fileinput
+import os
+import re
+import sys
+
+# fix-it:"../../base/threading/sequenced_worker_pool.h":{341:3-341:11}:""
+# Note that the file path is relative to the build directory.
+_FIXIT_RE = re.compile(r'^fix-it:"(?P<file>.+?)":'
+                       r'{(?P<start_line>\d+?):(?P<start_col>\d+?)-'
+                       r'(?P<end_line>\d+?):(?P<end_col>\d+?)}:'
+                       r'"(?P<text>.*?)"$')
+
+FixIt = collections.namedtuple(
+    'FixIt', ('start_line', 'start_col', 'end_line', 'end_col', 'text'))
+
+
+def main():
+  parser = argparse.ArgumentParser()
+  parser.add_argument(
+      'build_directory',
+      nargs='?',
+      default='out/Debug',
+      help='path to the build directory to complete relative paths in fixits')
+  args = parser.parse_args()
+
+  fixits = collections.defaultdict(list)
+  for line in fileinput.input():
+    if not line.startswith('fix-it:'):
+      continue
+    m = _FIXIT_RE.match(line)
+    if not m:
+      continue
+    # The negative line numbers are a cheap hack so we can sort things in line
+    # order but reverse column order. Applying the fixits in reverse order makes
+    # things simpler, since offsets won't have to be adjusted as the text is
+    # changed.
+    fixits[m.group('file')].append(FixIt(
+        int(m.group('start_line')), -int(m.group('start_col')), int(m.group(
+            'end_line')), -int(m.group('end_col')), m.group('text')))
+  for k, v in fixits.iteritems():
+    v.sort()
+    with open(os.path.join(args.build_directory, k), 'rb+') as f:
+      lines = f.readlines()
+      last_fixit = None
+      for fixit in v:
+        if fixit.start_line != fixit.end_line:
+          print 'error: multiline fixits not supported! file: %s, fixit: %s' % (
+              k, fixit)
+          sys.exit(1)
+        if fixit == last_fixit:
+          continue
+        last_fixit = fixit
+        # The line/column numbers emitted in fixit hints start at 1, so offset
+        # is appropriately.
+        line = lines[fixit.start_line - 1]
+        lines[fixit.start_line - 1] = (line[:-fixit.start_col - 1] + fixit.text
+                                       + line[-fixit.end_col - 1:])
+      f.seek(0)
+      f.truncate()
+      f.writelines(lines)
+
+
+if __name__ == '__main__':
+  sys.exit(main())