Remove dependency on scan-build wrapper script for Clang analysis builds.

build/toolchain/clang_static_analyzer_wrapper.py

 #!/usr/bin/env python
-# Copyright 2016 The Chromium Authors. All rights reserved.
+# Copyright 2017 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.
 
-"""Invokes the Clang static analysis command using arguments provided on the
-command line.
+"""Adds an analysis build step to invocations of the Clang C/C++ compiler.
+
+Usage: clang_static_analyzer_wrapper.py <compiler> [args...]
 """
 
 import argparse
 import fnmatch
+import itertools
 import os
-import shutil
 import sys
-import tempfile
+import wrapper_utils
 
-import wrapper_utils
+# Flags used to enable analysis for Clang invocations.
+analyzer_enable_flags = [
+    '--analyze',
+    '-fdiagnostics-show-option',
+]
+
+# Flags used to configure the analyzer's behavior.
+analyzer_option_flags = [
+    '-analyzer-checker=cplusplus',
+    '-analyzer-opt-analyze-nested-blocks',
+    '-analyzer-eagerly-assume',
+    '-analyzer-output=text',
+    '-analyzer-config',
+    'suppress-c++-stdlib=true',
+
+# List of checkers to execute.
+# The full list of checkers can be found at
+# https://clang-analyzer.llvm.org/available_checks.html.
+    '-analyzer-checker=core',
+    '-analyzer-checker=unix',
+    '-analyzer-checker=deadcode',
+]
 
 
 def main():
-  parser = argparse.ArgumentParser(description=__doc__)
-  parser.add_argument('--clang-cc-path',
-                      help='Path to the clang compiler.',
-                      metavar='PATH')
-  parser.add_argument('--clang-cxx-path',
-                      help='Path to the clang++ compiler',
-                      metavar='PATH')
-  parser.add_argument('--analyzer',
-                      help='Path to the language-specific Clang analysis tool.',
-                      required=True,
-                      metavar='PATH')
-  args, compile_args = parser.parse_known_args()
+  args = sys.argv[1:]
+  assert(args)

[Nico, 2017/03/10 01:55:02]

nit:
  assert args

(no parens needed)

[Kevin M, 2017/03/10 17:44:02]

Done.

 
-  # Check that only one of --clang-cc-path or --clang-cxx-path are set.
-  assert ((args.clang_cc_path != None) != (args.clang_cxx_path != None))
+  # Interleave 'analyzer_option_flags' flags w/'-Xanalyzer' so that Clang
+  # passes them to the analysis tool.
+  # e.g. ['-analyzer-foo', '-analyzer-bar'] => ['-Xanalyzer', '-analyzer-foo',
+  #                                             '-Xanalyzer', '-analyzer-bar']
+  interleaved_analyzer_flags = reduce(
+      lambda x, y: x + ['-Xanalyzer', y], analyzer_option_flags, [])

[Nico, 2017/03/10 01:55:02]

sum(zip([1, 2, 3], [4, 5, 6]), ())

=> maybe simpler to spell this

sum(zip(['-Xanalyzer'] * len(analyzer_option_flags), analyzer_option_flags), ())

?

[Kevin M, 2017/03/10 17:44:02]

Done.

 
-  is_cxx = args.clang_cxx_path != None
-  env = os.environ
-  env['CCC_ANALYZER_FORCE_ANALYZE_DEBUG_CODE'] = '0'
-  env['CCC_ANALYZER_OUTPUT_FORMAT'] = 'text'
-  clang_path = args.clang_cxx_path or args.clang_cc_path
-  if is_cxx:
-    env['CCC_CXX'] = clang_path
-    env['CLANG_CXX'] = clang_path
-  else:
-    env['CCC_CC'] = clang_path
-    env['CLANG'] = clang_path
+  returncode, stderr = wrapper_utils.CaptureCommandStderr(
+      wrapper_utils.CommandToRun(args + analyzer_enable_flags +
+                                 interleaved_analyzer_flags))
 
-  # TODO(kmarshall): Place the summarized output in a useful directory.
-  temp_dir = tempfile.mkdtemp()
-  try:
-    env['CCC_ANALYZER_HTML'] = temp_dir
-    returncode, stderr = wrapper_utils.CaptureCommandStderr(
-        wrapper_utils.CommandToRun([args.analyzer] + compile_args), env)
-    sys.stderr.write(stderr)
-    return returncode
-  finally:
-    shutil.rmtree(temp_dir)
+  # TODO(kmarshall): Post-process the analysis output and remove any eror text
+  # originating from excluded files. (crbug.com/688616)
+  sys.stderr.write(stderr)
 
-if __name__ == "__main__":
+  if returncode != 0:
+    # The analyzer is a little buggy and can crash midway through an AST parse
+    # on otherwise buildable code.
+    # If it fails, we should recover gracefully and continue with the build.
+    sys.stderr.write(
+        'WARNING: Clang analyzer exited with return code %d.\n' % (returncode))

[Nico, 2017/03/10 01:55:02]

I still think we shouldn't have this in here. Please add a "TODO: fix once all
crashes are fixed, crbug.com/XXX" and mention all known crashes there (and file
llvm bugs for them and mention them in the crbug)

[Kevin M, 2017/03/10 17:44:02]

There is the potential for new bugs and regressions to occur in the future. It
makes sense to wave our arms and call attention to the crbug in the logging
output so that Chromium developers know to take the appropriate action with the
crbug. Not many people will be reading this script for comments. :)

+
+  # Build the object file.
+  returncode, stderr = wrapper_utils.CaptureCommandStderr(
+    wrapper_utils.CommandToRun(args))
+
+  sys.stderr.write(stderr)
+  return returncode
+
+if __name__ == '__main__':
   sys.exit(main())