2 # Copyright 2018 The Chromium Authors
3 # Use of this source code is governed by a BSD-style license that can be
4 # found in the LICENSE file.
5 """Removes code coverage flags from invocations of the Clang C/C++ compiler.
7 If the GN arg `use_clang_coverage=true`, this script will be invoked by default.
8 GN will add coverage instrumentation flags to almost all source files.
10 This script is used to remove instrumentation flags from a subset of the source
11 files. By default, it will not remove flags from any files. If the option
12 --files-to-instrument is passed, this script will remove flags from all files
13 except the ones listed in --files-to-instrument.
15 This script also contains hard-coded exclusion lists of files to never
16 instrument, indexed by target operating system. Files in these lists have their
17 flags removed in both modes. The OS can be selected with --target-os.
19 This script also contains hard-coded force lists of files to always instrument,
20 indexed by target operating system. Files in these lists never have their flags
21 removed in either mode. The OS can be selected with --target-os.
23 The order of precedence is: force list, exclusion list, --files-to-instrument.
25 The path to the coverage instrumentation input file should be relative to the
26 root build directory, and the file consists of multiple lines where each line
27 represents a path to a source file, and the specified paths must be relative to
28 the root build directory. e.g. ../../base/task/post_task.cc for build
29 directory 'out/Release'. The paths should be written using OS-native path
30 separators for the current platform.
32 One caveat with this compiler wrapper is that it may introduce unexpected
33 behaviors in incremental builds when the file path to the coverage
34 instrumentation input file changes between consecutive runs, so callers of this
35 script are strongly advised to always use the same path such as
36 "${root_build_dir}/coverage_instrumentation_input.txt".
38 It's worth noting on try job builders, if the contents of the instrumentation
39 file changes so that a file doesn't need to be instrumented any longer, it will
40 be recompiled automatically because if try job B runs after try job A, the files
41 that were instrumented in A will be updated (i.e., reverted to the checked in
42 version) in B, and so they'll be considered out of date by ninja and recompiled.
45 clang_code_coverage_wrapper.py \\
46 --files-to-instrument=coverage_instrumentation_input.txt
48 Siso implements the same logic in
49 build/config/siso/clang_code_coverage_wrapper.star, which avoids the wrapper
50 invocations for remote execution and performance improvement.
51 Please update the Siso starlark file when updating this file.
60 # Flags used to enable coverage instrumentation.
61 # Flags should be listed in the same order that they are added in
62 # build/config/coverage/BUILD.gn
64 '-fprofile-instr-generate',
66 # Following experimental flags remove unused header functions from the
67 # coverage mapping data embedded in the test binaries, and the reduction
68 # of binary size enables building Chrome's large unit test targets on
69 # MacOS. Please refer to crbug.com/796290 for more details.
71 '-limited-coverage-experimental=true',
74 # Files that should not be built with coverage flags by default.
75 _DEFAULT_COVERAGE_EXCLUSION_LIST = []
77 # Map of exclusion lists indexed by target OS.
78 # If no target OS is defined, or one is defined that doesn't have a specific
79 # entry, use _DEFAULT_COVERAGE_EXCLUSION_LIST.
80 _COVERAGE_EXCLUSION_LIST_MAP = {
82 # This file caused webview native library failed on arm64.
83 '../../device/gamepad/dualshock4_controller.cc',
86 # TODO(crbug.com/1174725): These files caused clang to crash while
88 '../../base/allocator/partition_allocator/src/partition_alloc/pcscan.cc',
89 '../../third_party/skia/src/core/SkOpts.cpp',
90 '../../third_party/skia/src/opts/SkOpts_hsw.cpp',
91 '../../third_party/skia/third_party/skcms/skcms.cc',
94 # These files caused a static initializer to be generated, which
96 # TODO(crbug.com/990948): Remove when the bug is fixed.
97 '../../chrome/browser/media/router/providers/cast/cast_internal_message_util.cc', #pylint: disable=line-too-long
98 '../../components/media_router/common/providers/cast/channel/cast_channel_enum.cc', #pylint: disable=line-too-long
99 '../../components/media_router/common/providers/cast/channel/cast_message_util.cc', #pylint: disable=line-too-long
100 '../../components/media_router/common/providers/cast/cast_media_source.cc', #pylint: disable=line-too-long
101 '../../ui/events/keycodes/dom/keycode_converter.cc',
104 # These files caused clang to crash while compiling them. They are
105 # excluded pending an investigation into the underlying compiler bug.
106 '../../third_party/webrtc/p2p/base/p2p_transport_channel.cc',
107 '../../third_party/icu/source/common/uts46.cpp',
108 '../../third_party/icu/source/common/ucnvmbcs.cpp',
109 '../../base/android/android_image_reader_compat.cc',
113 # Map of force lists indexed by target OS.
114 _COVERAGE_FORCE_LIST_MAP = {
115 # clang_profiling.cc refers to the symbol `__llvm_profile_dump` from the
116 # profiling runtime. In a partial coverage build, it is possible for a
117 # binary to include clang_profiling.cc but have no instrumented files, thus
118 # causing an unresolved symbol error because the profiling runtime will not
119 # be linked in. Therefore we force coverage for this file to ensure that
120 # any target that includes it will also get the profiling runtime.
121 'win': [r'..\..\base\test\clang_profiling.cc'],
122 # TODO(crbug.com/1141727) We're seeing runtime LLVM errors in mac-rel when
123 # no files are changed, so we suspect that this is similar to the other
124 # problem with clang_profiling.cc on Windows. The TODO here is to force
125 # coverage for this specific file on ALL platforms, if it turns out to fix
126 # this issue on Mac as well. It's the only file that directly calls
127 # `__llvm_profile_dump` so it warrants some special treatment.
128 'mac': ['../../base/test/clang_profiling.cc'],
132 def _remove_flags_from_command(command):
133 # We need to remove the coverage flags for this file, but we only want to
134 # remove them if we see the exact sequence defined in _COVERAGE_FLAGS.
135 # That ensures that we only remove the flags added by GN when
136 # "use_clang_coverage" is true. Otherwise, we would remove flags set by
137 # other parts of the build system.
138 start_flag = _COVERAGE_FLAGS[0]
139 num_flags = len(_COVERAGE_FLAGS)
143 idx = command.index(start_flag, start_idx)
144 if command[idx:idx + num_flags] == _COVERAGE_FLAGS:
145 del command[idx:idx + num_flags]
146 # There can be multiple sets of _COVERAGE_FLAGS. All of these need to be
156 arg_parser = argparse.ArgumentParser()
157 arg_parser.usage = __doc__
158 arg_parser.add_argument(
159 '--files-to-instrument',
161 help='Path to a file that contains a list of file names to instrument.')
162 arg_parser.add_argument(
163 '--target-os', required=False, help='The OS to compile for.')
164 arg_parser.add_argument('args', nargs=argparse.REMAINDER)
165 parsed_args = arg_parser.parse_args()
167 if (parsed_args.files_to_instrument and
168 not os.path.isfile(parsed_args.files_to_instrument)):
169 raise Exception('Path to the coverage instrumentation file: "%s" doesn\'t '
170 'exist.' % parsed_args.files_to_instrument)
172 compile_command = parsed_args.args
173 if not any('clang' in s for s in compile_command):
174 return subprocess.call(compile_command)
176 target_os = parsed_args.target_os
179 # The command is assumed to use Clang as the compiler, and the path to the
180 # source file is behind the -c argument, and the path to the source path is
181 # relative to the root build directory. For example:
182 # clang++ -fvisibility=hidden -c ../../base/files/file_path.cc -o \
183 # obj/base/base/file_path.o
184 # On Windows, clang-cl.exe uses /c instead of -c.
185 source_flag = '/c' if target_os == 'win' else '-c'
186 source_flag_index = compile_command.index(source_flag)
188 print('%s argument is not found in the compile command.' % source_flag)
191 if source_flag_index + 1 >= len(compile_command):
192 raise Exception('Source file to be compiled is missing from the command.')
194 # On Windows, filesystem paths should use '\', but GN creates build commands
195 # that use '/'. We invoke os.path.normpath to ensure that the path uses the
196 # correct separator for the current platform (i.e. '\' on Windows and '/'
198 compile_source_file = os.path.normpath(compile_command[source_flag_index + 1])
199 extension = os.path.splitext(compile_source_file)[1]
200 if not extension in ['.c', '.cc', '.cpp', '.cxx', '.m', '.mm', '.S']:
201 raise Exception('Invalid source file %s found' % compile_source_file)
202 exclusion_list = _COVERAGE_EXCLUSION_LIST_MAP.get(
203 target_os, _DEFAULT_COVERAGE_EXCLUSION_LIST)
204 force_list = _COVERAGE_FORCE_LIST_MAP.get(target_os, [])
206 should_remove_flags = False
207 if compile_source_file not in force_list:
208 if compile_source_file in exclusion_list:
209 should_remove_flags = True
210 elif parsed_args.files_to_instrument:
211 with open(parsed_args.files_to_instrument) as f:
212 if compile_source_file not in f.read():
213 should_remove_flags = True
215 if should_remove_flags:
216 _remove_flags_from_command(compile_command)
218 return subprocess.call(compile_command)
221 if __name__ == '__main__':
224 # LINT.ThenChange(/build/config/siso/clang_code_coverage_wrapper.star)