1#!/usr/bin/env python3 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. 6 7If the GN arg `use_clang_coverage=true`, this script will be invoked by default. 8GN will add coverage instrumentation flags to almost all source files. 9 10This script is used to remove instrumentation flags from a subset of the source 11files. 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 13except the ones listed in --files-to-instrument. 14 15This script also contains hard-coded exclusion lists of files to never 16instrument, indexed by target operating system. Files in these lists have their 17flags removed in both modes. The OS can be selected with --target-os. 18 19This script also contains hard-coded force lists of files to always instrument, 20indexed by target operating system. Files in these lists never have their flags 21removed in either mode. The OS can be selected with --target-os. 22 23The order of precedence is: force list, exclusion list, --files-to-instrument. 24 25The path to the coverage instrumentation input file should be relative to the 26root build directory, and the file consists of multiple lines where each line 27represents a path to a source file, and the specified paths must be relative to 28the root build directory. e.g. ../../base/task/post_task.cc for build 29directory 'out/Release'. The paths should be written using OS-native path 30separators for the current platform. 31 32One caveat with this compiler wrapper is that it may introduce unexpected 33behaviors in incremental builds when the file path to the coverage 34instrumentation input file changes between consecutive runs, so callers of this 35script are strongly advised to always use the same path such as 36"${root_build_dir}/coverage_instrumentation_input.txt". 37 38It's worth noting on try job builders, if the contents of the instrumentation 39file changes so that a file doesn't need to be instrumented any longer, it will 40be recompiled automatically because if try job B runs after try job A, the files 41that were instrumented in A will be updated (i.e., reverted to the checked in 42version) in B, and so they'll be considered out of date by ninja and recompiled. 43 44Example usage: 45 clang_code_coverage_wrapper.py \\ 46 --files-to-instrument=coverage_instrumentation_input.txt 47 48Siso implements the same logic in 49build/config/siso/clang_code_coverage_wrapper.star, which avoids the wrapper 50invocations for remote execution and performance improvement. 51Please update the Siso starlark file when updating this file. 52""" 53# LINT.IfChange 54 55import argparse 56import os 57import subprocess 58import sys 59 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 63_COVERAGE_FLAGS = [ 64 '-fprofile-instr-generate', 65 '-fcoverage-mapping', 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. 70 '-mllvm', 71 '-limited-coverage-experimental=true', 72] 73 74# Files that should not be built with coverage flags by default. 75_DEFAULT_COVERAGE_EXCLUSION_LIST = [] 76 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 = { 81 'android': [ 82 # This file caused webview native library failed on arm64. 83 '../../device/gamepad/dualshock4_controller.cc', 84 ], 85 'fuchsia': [ 86 # TODO(crbug.com/1174725): These files caused clang to crash while 87 # compiling them. 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', 92 ], 93 'linux': [ 94 # These files caused a static initializer to be generated, which 95 # shouldn't. 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', 102 ], 103 'chromeos': [ 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', 110 ], 111} 112 113# 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'], 129} 130 131 132def _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) 140 start_idx = 0 141 try: 142 while True: 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 147 # removed. 148 start_idx = idx 149 else: 150 start_idx = idx + 1 151 except ValueError: 152 pass 153 154 155def main(): 156 arg_parser = argparse.ArgumentParser() 157 arg_parser.usage = __doc__ 158 arg_parser.add_argument( 159 '--files-to-instrument', 160 type=str, 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() 166 167 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) 171 172 compile_command = parsed_args.args 173 if not any('clang' in s for s in compile_command): 174 return subprocess.call(compile_command) 175 176 target_os = parsed_args.target_os 177 178 try: 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) 187 except ValueError: 188 print('%s argument is not found in the compile command.' % source_flag) 189 raise 190 191 if source_flag_index + 1 >= len(compile_command): 192 raise Exception('Source file to be compiled is missing from the command.') 193 194 # 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 '/' 197 # otherwise). 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, []) 205 206 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 214 215 if should_remove_flags: 216 _remove_flags_from_command(compile_command) 217 218 return subprocess.call(compile_command) 219 220 221if __name__ == '__main__': 222 sys.exit(main()) 223 224# LINT.ThenChange(/build/config/siso/clang_code_coverage_wrapper.star) 225