bb571bd6cb
This CL implements the Clang code coverage compiler wrapper, which can be used to instrument a subset of source files, and the main use case is to enable generating code coverage reports at per-cl level during try jobs. This CL only focuses on the wrapper itself, how to hook this wrapper into the build system will be addressed in a separate CL. Bug: 898695 Change-Id: Idb21640b5566ce78089059b3d0116390b488a383 Reviewed-on: https://chromium-review.googlesource.com/c/1301969 Commit-Queue: Yuke Liao <liaoyuke@chromium.org> Reviewed-by: Dirk Pranke <dpranke@chromium.org> Reviewed-by: Takuto Ikuta <tikuta@chromium.org> Cr-Commit-Position: refs/heads/master@{#604381}
84 lines
3.3 KiB
Python
Executable File
84 lines
3.3 KiB
Python
Executable File
#!/usr/bin/env python
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# Copyright 2018 The Chromium Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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"""Adds code coverage flags to the invocations of the Clang C/C++ compiler.
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This script is used to instrument a subset of the source files, and the list of
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files to instrument is specified by an input file that is passed to this script
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as a command-line argument.
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The path to the coverage instrumentation input file should be relative to the
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root build directory, and the file consists of multiple lines where each line
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represents a path to a source file, and the specified paths must be relative to
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the root build directory. e.g. ../../base/task/post_task.cc for build
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directory 'out/Release'.
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One caveat with this compiler wrapper is that it may introduce unexpected
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behaviors in incremental builds when the file path to the coverage
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instrumentation input file changes between consecutive runs, so callers of this
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script are strongly advised to always use the same path such as
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"${root_build_dir}/coverage_instrumentation_input.txt".
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It's worth noting on try job builders, if the contents of the instrumentation
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file changes so that a file doesn't need to be instrumented any longer, it will
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be recompiled automatically because if try job B runs after try job A, the files
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that were instrumented in A will be updated (i.e., reverted to the checked in
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version) in B, and so they'll be considered out of date by ninja and recompiled.
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Example usage:
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clang_code_coverage_wrapper.py \\
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--files-to-instrument=coverage_instrumentation_input.txt
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"""
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import argparse
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import os
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import subprocess
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import sys
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# Flags used to enable coverage instrumentation.
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_COVERAGE_FLAGS = ['-fprofile-instr-generate', '-fcoverage-mapping']
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def main():
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# TODO(crbug.com/898695): Make this wrapper work on Windows platform.
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arg_parser = argparse.ArgumentParser()
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arg_parser.usage = __doc__
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arg_parser.add_argument(
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'--files-to-instrument',
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type=str,
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required=True,
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help='Path to a file that contains a list of file names to instrument.')
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arg_parser.add_argument('args', nargs=argparse.REMAINDER)
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parsed_args = arg_parser.parse_args()
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if not os.path.isfile(parsed_args.files_to_instrument):
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raise Exception('Path to the coverage instrumentation file: "%s" doesn\'t '
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'exist.' % parsed_args.files_to_instrument)
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compile_command = parsed_args.args
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try:
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# The command is assumed to use Clang as the compiler, and the path to the
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# source file is behind the -c argument, and the path to the source path is
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# relative to the root build directory. For example:
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# clang++ -fvisibility=hidden -c ../../base/files/file_path.cc -o \
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# obj/base/base/file_path.o
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index_dash_c = compile_command.index('-c')
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except ValueError:
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print '-c argument is not found in the compile command.'
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raise
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if index_dash_c + 1 >= len(compile_command):
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raise Exception('Source file to be compiled is missing from the command.')
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compile_source_file = compile_command[index_dash_c + 1]
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with open(parsed_args.files_to_instrument) as f:
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if compile_source_file + '\n' in f.read():
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compile_command.extend(_COVERAGE_FLAGS)
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return subprocess.call(compile_command)
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if __name__ == '__main__':
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sys.exit(main())
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