clang-tidy helper script, with clang static analyzer included.

This CL makes it easy to invoke the tool for single cc files,
without having to install or configure anything.
It boils down to:
% tools_webrtc/clang_tidy.py path/to/file.cc [clang-tidy-args...]
If any issue is encountered, a colored diagnostic will be printed.
By default, it also includes checks from clang analyzer.

Warning! This is linux-only, and uses an old version of
clang-tidy based on LLVM 5.0. USE WITH CARE.

bug: webrtc:8793
Change-Id: I8964f2b939408326cc349c5f0ac0dfcff2da24c5
Reviewed-on: https://webrtc-review.googlesource.com/c/120221
Commit-Queue: Yves Gerey <yvesg@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26858}

PRESUBMIT.py

@@ -580,7 +580,7 @@ def CheckGnGen(input_api, output_api):
   """
   with _AddToPath(input_api.os_path.join(
       input_api.PresubmitLocalPath(), 'tools_webrtc', 'presubmit_checks_lib')):
-    from gn_check import RunGnCheck
+    from build_helpers import RunGnCheck
   errors = RunGnCheck(FindSrcDirPath(input_api.PresubmitLocalPath()))[:5]
   if errors:
     return [output_api.PresubmitPromptWarning(

tools_webrtc/clang_tidy.py

@@ -0,0 +1,96 @@
+#!/usr/bin/env python
+# Copyright (c) 2019 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+"""Invoke clang-tidy tool.
+
+Usage: clang_tidy.py file.cc [clang-tidy-args...]
+
+Just a proof of concept!
+We use an embedded clang-tidy whose version doesn't match clang++.
+"""
+
+import argparse
+import os
+import shutil
+import subprocess
+import sys
+import tempfile
+#pylint: disable=relative-import
+from presubmit_checks_lib.build_helpers import GetClangTidyPath, \
+  GetCompilationCommand
+
+
+# We enable all checkers by default for investigation purpose.
+# This includes clang-analyzer-* checks.
+# Individual checkers can be disabled via command line options.
+# TODO(bugs.webrtc.com/10258): Select checkers relevant to webrtc guidelines.
+CHECKER_OPTION = '-checks=*'
+
+
+def Process(filepath, args):
+  # Build directory is needed to gather compilation flags.
+  # Create a temporary one (instead of reusing an existing one)
+  # to keep the CLI simple and unencumbered.
+  out_dir = tempfile.mkdtemp('clang_tidy')
+
+  try:
+    gn_args = []  # Use default build.
+    command = GetCompilationCommand(filepath, gn_args, out_dir)
+
+    # Remove warning flags. They aren't needed and they cause trouble
+    # when clang-tidy doesn't match most recent clang.
+    # Same battle for -f (e.g. -fcomplete-member-pointers).
+    command = [arg for arg in command if not (arg.startswith('-W') or
+                                              arg.startswith('-f'))]
+
+    # Path from build dir.
+    rel_path = os.path.relpath(os.path.abspath(filepath), out_dir)
+
+    # Replace clang++ by clang-tidy
+    command[0:1] = [GetClangTidyPath(),
+                    CHECKER_OPTION,
+                    rel_path] + args + ['--']  # Separator for clang flags.
+    print "Running: %s" % ' '.join(command)
+    # Run from build dir so that relative paths are correct.
+    p = subprocess.Popen(command, cwd=out_dir,
+                         stdout=sys.stdout, stderr=sys.stderr)
+    p.communicate()
+    return p.returncode
+  finally:
+    shutil.rmtree(out_dir, ignore_errors=True)
+
+
+def ValidateCC(filepath):
+  """We can only analyze .cc files. Provide explicit message about that."""
+  if filepath.endswith('.cc'):
+    return filepath
+  msg = ('%s not supported.\n'
+         'For now, we can only analyze translation units (.cc files).' %
+         filepath)
+  raise argparse.ArgumentTypeError(msg)
+
+
+def Main():
+  description = (
+    "Run clang-tidy on single cc file.\n"
+    "Use flags, defines and include paths as in default debug build.\n"
+    "WARNING, this is a POC version with rough edges.")
+  parser = argparse.ArgumentParser(description=description)
+  parser.add_argument('filepath',
+                      help='Specifies the path of the .cc file to analyze.',
+                      type=ValidateCC)
+  parser.add_argument('args',
+                      nargs=argparse.REMAINDER,
+                      help='Arguments passed to clang-tidy')
+  parsed_args = parser.parse_args()
+  return Process(parsed_args.filepath, parsed_args.args)
+
+
+if __name__ == '__main__':
+  sys.exit(Main())

tools_webrtc/presubmit_checks_lib/build_helpers.py

@@ -0,0 +1,134 @@
+# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+"""This script helps to invoke gn and ninja
+which lie in depot_tools repository."""
+
+import json
+import os
+import re
+import shutil
+import subprocess
+import sys
+import tempfile
+
+
+def FindSrcDirPath():
+  """Returns the abs path to the src/ dir of the project."""
+  src_dir = os.path.dirname(os.path.abspath(__file__))
+  while os.path.basename(src_dir) != 'src':
+    src_dir = os.path.normpath(os.path.join(src_dir, os.pardir))
+  return src_dir
+
+
+SRC_DIR = FindSrcDirPath()
+sys.path.append(os.path.join(SRC_DIR, 'build'))
+import find_depot_tools
+
+
+def RunGnCommand(args, root_dir=None):
+  """Runs `gn` with provided args and return error if any."""
+  try:
+    command = [
+      sys.executable,
+      os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'gn.py')
+    ] + args
+    subprocess.check_output(command, cwd=root_dir)
+  except subprocess.CalledProcessError as err:
+    return err.output
+  return None
+
+
+# GN_ERROR_RE matches the summary of an error output by `gn check`.
+# Matches "ERROR" and following lines until it sees an empty line or a line
+# containing just underscores.
+GN_ERROR_RE = re.compile(r'^ERROR .+(?:\n.*[^_\n].*$)+', re.MULTILINE)
+
+
+def RunGnCheck(root_dir=None):
+  """Runs `gn gen --check` with default args to detect mismatches between
+  #includes and dependencies in the BUILD.gn files, as well as general build
+  errors.
+
+  Returns a list of error summary strings.
+  """
+  out_dir = tempfile.mkdtemp('gn')
+  try:
+    error = RunGnCommand(['gen', '--check', out_dir], root_dir)
+  finally:
+    shutil.rmtree(out_dir, ignore_errors=True)
+  return GN_ERROR_RE.findall(error) if error else []
+
+
+def RunNinjaCommand(args, root_dir=None):
+  """Runs ninja quietly. Any failure (e.g. clang not found) is
+     silently discarded, since this is unlikely an error in submitted CL."""
+  command = [
+              os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'ninja')
+            ] + args
+  p = subprocess.Popen(command, cwd=root_dir,
+                       stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+  out, _ = p.communicate()
+  return out
+
+
+def GetClangTidyPath():
+  """POC/WIP! Use the one we have, even it doesn't match clang's version."""
+  tidy = ('third_party/android_ndk/toolchains/'
+          'llvm/prebuilt/linux-x86_64/bin/clang-tidy')
+  return os.path.join(SRC_DIR, tidy)
+
+
+def GetCompilationDb(root_dir=None):
+  """Run ninja compdb tool to get proper flags, defines and include paths."""
+  # The compdb tool expect a rule.
+  commands = json.loads(RunNinjaCommand(['-t', 'compdb', 'cxx'], root_dir))
+  # Turns 'file' field into a key.
+  return {v['file']: v for v in commands}
+
+
+def GetCompilationCommand(filepath, gn_args, work_dir):
+  """Get the whole command used to compile one cc file.
+  Typically, clang++ with flags, defines and include paths.
+
+  Args:
+      filepath: path to .cc file.
+      gen_args: build configuration for gn.
+      work_dir: build dir.
+
+  Returns:
+    Command as a list, ready to be consumed by subprocess.Popen.
+  """
+  gn_errors = RunGnCommand(['gen'] + gn_args + [work_dir])
+  if gn_errors:
+    raise(RuntimeError(
+      'FYI, cannot complete check due to gn error:\n%s\n'
+      'Please open a bug.' % gn_errors))
+
+  # Needed for single file compilation.
+  commands = GetCompilationDb(work_dir)
+
+  # Path as referenced by ninja.
+  rel_path = os.path.relpath(os.path.abspath(filepath), work_dir)
+
+  # Gather defines, include path and flags (such as -std=c++11).
+  try:
+    compilation_entry = commands[rel_path]
+  except KeyError:
+    raise ValueError('%s: Not found in compilation database.\n'
+                     'Please check the path.' % filepath)
+  command = compilation_entry['command'].split()
+
+  # Remove troublesome flags. May trigger an error otherwise.
+  if '-MMD' in command:
+    command.remove('-MMD')
+  if '-MF' in command:
+    index = command.index('-MF')
+    del command[index:index+2]  # Remove filename as well.
+
+  return command

tools_webrtc/presubmit_checks_lib/build_helpers_test.py

@@ -11,7 +11,8 @@
 import os
 import unittest
 
-from gn_check import RunGnCheck
+#pylint: disable=relative-import
+import build_helpers
 
 
 TESTDATA_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)),
@@ -23,7 +24,8 @@ class GnCheckTest(unittest.TestCase):
     test_dir = os.path.join(TESTDATA_DIR, 'circular_dependency')
     expected_errors = ['ERROR Dependency cycle:\n'
                        '  //:bar ->\n  //:foo ->\n  //:bar']
-    self.assertListEqual(expected_errors, RunGnCheck(test_dir))
+    self.assertListEqual(expected_errors,
+                         build_helpers.RunGnCheck(test_dir))
 
 
 if __name__ == '__main__':

tools_webrtc/presubmit_checks_lib/check_orphan_headers_test.py

@@ -11,6 +11,7 @@ import os
 import sys
 import unittest
 
+#pylint: disable=relative-import
 import check_orphan_headers
 
 

tools_webrtc/presubmit_checks_lib/check_package_boundaries_test.py

@@ -12,6 +12,7 @@ import ast
 import os
 import unittest
 
+#pylint: disable=relative-import
 from check_package_boundaries import CheckPackageBoundaries
 
 

tools_webrtc/presubmit_checks_lib/gn_check.py

@@ -1,58 +0,0 @@
-# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
-#
-# Use of this source code is governed by a BSD-style license
-# that can be found in the LICENSE file in the root of the source
-# tree. An additional intellectual property rights grant can be found
-# in the file PATENTS.  All contributing project authors may
-# be found in the AUTHORS file in the root of the source tree.
-
-import os
-import re
-import shutil
-import subprocess
-import sys
-import tempfile
-
-
-def FindSrcDirPath():
-  """Returns the abs path to the src/ dir of the project."""
-  src_dir = os.path.dirname(os.path.abspath(__file__))
-  while os.path.basename(src_dir) != 'src':
-    src_dir = os.path.normpath(os.path.join(src_dir, os.pardir))
-  return src_dir
-
-
-SRC_DIR = FindSrcDirPath()
-sys.path.append(os.path.join(SRC_DIR, 'build'))
-import find_depot_tools
-
-
-# GN_ERROR_RE matches the summary of an error output by `gn check`.
-# Matches "ERROR" and following lines until it sees an empty line or a line
-# containing just underscores.
-GN_ERROR_RE = re.compile(r'^ERROR .+(?:\n.*[^_\n].*$)+', re.MULTILINE)
-
-
-def RunGnCheck(root_dir=None):
-  """Runs `gn gen --check` with default args to detect mismatches between
-  #includes and dependencies in the BUILD.gn files, as well as general build
-  errors.
-
-  Returns a list of error summary strings.
-  """
-  out_dir = tempfile.mkdtemp('gn')
-  try:
-    command = [
-      sys.executable,
-      os.path.join(find_depot_tools.DEPOT_TOOLS_PATH, 'gn.py'),
-      'gen',
-      '--check',
-      out_dir,
-    ]
-    subprocess.check_output(command, cwd=root_dir)
-  except subprocess.CalledProcessError as err:
-    return GN_ERROR_RE.findall(err.output)
-  else:
-    return []
-  finally:
-    shutil.rmtree(out_dir, ignore_errors=True)