From patchwork Thu Dec 6 22:23:18 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Roeder X-Patchwork-Id: 10717125 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 4415914E2 for ; Thu, 6 Dec 2018 22:23:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 32D202A2AB for ; Thu, 6 Dec 2018 22:23:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2535B2A645; Thu, 6 Dec 2018 22:23:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.5 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, USER_IN_DEF_DKIM_WL autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 68DC82A2AB for ; Thu, 6 Dec 2018 22:23:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726043AbeLFWXx (ORCPT ); Thu, 6 Dec 2018 17:23:53 -0500 Received: from mail-qt1-f202.google.com ([209.85.160.202]:47659 "EHLO mail-qt1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725945AbeLFWXw (ORCPT ); Thu, 6 Dec 2018 17:23:52 -0500 Received: by mail-qt1-f202.google.com with SMTP id b26so1883906qtq.14 for ; Thu, 06 Dec 2018 14:23:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=50o4MvtjLTdhL3u0ZwwFnXOeAd7cA9fIDGEIiqzQvao=; b=AZei+II2V6jWx0me6vDCCyk0FIhbhE8opLZeexdh9DmxcCLX4hvVdEAcN6E2zWa10q LY1sTCif6FTGn5I2rusoGg9XR4JvaFvA4MchJgB0PDvnFjd7ebXnfNwA4rNSxWTwqxs1 yZ+jwLi3PHmtQQ9uoXI+cNNH8wF8Di5e/3DbqSmKKAJXsRyLfXG2PfEpU7cZogBuA56Z dNJs7a60Jx4PXNJBdFuJstSu4PSm64KzgIHhjGvXESKL9IGUyDv7o03Z7ms/oWIwTa8O N7M/wVy158EGCqDp8Gk27Acn3ggJjwXaVut8zeh4z+Uk+GztEPFvMqLTKG4e+4z+1n2V 8+qw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=50o4MvtjLTdhL3u0ZwwFnXOeAd7cA9fIDGEIiqzQvao=; b=FCTlRtGSboXjTOJTBNaP4AUOuqeY6Ix0eJ9hz1UQ7Ll548E6wlvrH8Hxy2GIMEQ9UO QFdMy0ZgIMOVSy0D0QS9rITS4l8ILSq83rTXgt4illV76NrMAawoWTnda6fMwLAh4AV9 rIs3LGl71+oX13fybZOi31v2ZzSoFPYd/QhNEYlPQaCATRFsy2p9/FSDGxiJOra9Frha OF4vw7Rd6ay6st00Io2Nd2IU4/Wyx8oJUiXEI27qOjoh6L0QfzvqEOMCQt9nWyXOf7GU p7u/Ocq8lGH0N/JlTRx5Ybh8BQ0/+Qh3Qa3efD9cTHTOc+T/SG4NFV3PQdw7h1AOtCga XgyA== X-Gm-Message-State: AA+aEWZOyY/icLDOh2CKn56nH6IexvHXZLPIiQrP17Kn68neRWutfjtj a5H90aU0W5S/oxrzFc0eMSvinjtmF5RFfg== X-Google-Smtp-Source: AFSGD/UXXY8g2CPTbqMvLEz+PJH0Ny3gcdb4PNzFYEuKY1tJVUhKl/ujqNQzpAG4utta+JOJE4qA8XBUiOqAiA== X-Received: by 2002:a0c:879a:: with SMTP id 26mr22484767qvj.62.1544135031575; Thu, 06 Dec 2018 14:23:51 -0800 (PST) Date: Thu, 6 Dec 2018 14:23:18 -0800 Message-Id: <20181206222318.218157-1-tmroeder@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.20.0.rc2.403.gdbc3b29805-goog Subject: [PATCH] scripts: add a tool to produce a compile_commands.json file From: Tom Roeder To: Masahiro Yamada , Michal Marek Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Tom Roeder Sender: linux-kbuild-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kbuild@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The LLVM/Clang project provides many tools for analyzing C source code. Many of these tools are based on LibTooling (https://clang.llvm.org/docs/LibTooling.html), which depends on a database of compiler flags. The standard container for this database is compile_commands.json, which consists of a list of JSON objects, each with "directory", "file", and "command" fields. Some build systems, like cmake or bazel, produce this compilation information directly. Naturally, Makefiles don't. However, the kernel makefiles already create ..o.cmd files that contain all the information needed to build a compile_commands.json file. So, this commit adds scripts/gen_compile_commands.py, which recursively searches through a directory for ..o.cmd files and extracts appropriate compile commands from them. It writes a compile_commands.json file that LibTooling-based tools can use. By default, gen_compile_commands.py starts its search in its working directory and (over)writes compile_commands.json in the working directory. However, it also supports --output and --directory flags for out-of-tree use. Note that while gen_compile_commands.py enables the use of clang-based tools, it does not require the kernel to be compiled with clang. E.g., the following sequence of commands produces a compile_commands.json file that works correctly with LibTooling. make defconfig make scripts/gen_compile_commands.py Also note that this script is written to work correctly in both Python 2 and Python 3, so it does not specify the Python version in its first line. For an example of the utility of this script: after running gen_compile_commands.json on the latest kernel version, I was able to use Vim + the YouCompleteMe pluging + clangd to automatically jump to definitions and declarations. Obviously, cscope and ctags provide some of this functionality; the advantage of supporting LibTooling is that it opens the door to many other clang-based tools that understand the code directly and do not rely on regular expressions and heuristics. Tested: Built several recent kernel versions and ran the script against them, testing tools like clangd (for editor/LSP support) and clang-check (for static analysis). Also extracted some test .cmd files from a kernel build and wrote a test script to check that the script behaved correctly with all permutations of the --output and --directory flags. Signed-off-by: Tom Roeder --- scripts/gen_compile_commands.py | 146 ++++++++++++++++++++++++++++++++ 1 file changed, 146 insertions(+) create mode 100755 scripts/gen_compile_commands.py diff --git a/scripts/gen_compile_commands.py b/scripts/gen_compile_commands.py new file mode 100755 index 000000000000..d6c4d7281976 --- /dev/null +++ b/scripts/gen_compile_commands.py @@ -0,0 +1,146 @@ +#!/usr/bin/env python +# SPDX-License-Identifier: GPL-2.0 +# +# Copyright (C) Google LLC, 2018 +# +# Author: Tom Roeder +# +"""A tool for generating compile_commands.json in the Linux kernel.""" + +import argparse +import json +import logging +import os +import re + +_DEFAULT_OUTPUT = 'compile_commands.json' +_DEFAULT_LOG_LEVEL = 'WARNING' + +_FILENAME_PATTERN = r'^\..*\.cmd$' +_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$' +_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL'] + +# A kernel build generally has over 2000 entries in its compile_commands.json +# database. If this code finds 500 or fewer, then warn the user that they might +# not have all the .cmd files, and they might need to compile the kernel. +_LOW_COUNT_THRESHOLD = 500 + + +def parse_arguments(): + """Sets up and parses command-line arguments. + + Returns: + log_level: A logging level to filter log output. + directory: The directory to search for .cmd files. + output: Where to write the compile-commands JSON file. + """ + usage = 'Creates a compile_commands.json database from kernel .cmd files' + parser = argparse.ArgumentParser(description=usage) + + directory_help = ('Path to the kernel source directory to search ' + '(defaults to the working directory)') + parser.add_argument('-d', '--directory', type=str, help=directory_help) + + output_help = ('The location to write compile_commands.json (defaults to ' + 'compile_commands.json in the search directory)') + parser.add_argument('-o', '--output', type=str, help=output_help) + + log_level_help = ('The level of log messages to produce (one of ' + + ', '.join(_VALID_LOG_LEVELS) + '; defaults to ' + + _DEFAULT_LOG_LEVEL + ')') + parser.add_argument( + '--log_level', type=str, default=_DEFAULT_LOG_LEVEL, + help=log_level_help) + + args = parser.parse_args() + + log_level = args.log_level + if log_level not in _VALID_LOG_LEVELS: + raise ValueError('%s is not a valid log level' % log_level) + + directory = args.directory or os.getcwd() + output = args.output or os.path.join(directory, _DEFAULT_OUTPUT) + directory = os.path.abspath(directory) + + return log_level, directory, output + + +def process_line(root_directory, file_directory, command_prefix, relative_path): + """Extracts information from a .cmd line and creates an entry from it. + + Args: + root_directory: The directory that was searched for .cmd files. Usually + used directly in the "directory" entry in compile_commands.json. + file_directory: The path to the directory the .cmd file was found in. + command_prefix: The extracted command line, up to the last element. + relative_path: The .c file from the end of the extracted command. + Usually relative to root_directory, but sometimes relative to + file_directory and sometimes neither. + + Returns: + An entry to append to compile_commands. + + Raises: + ValueError: Could not find the extracted file based on relative_path and + root_directory or file_directory. + """ + + cur_dir = root_directory + expected_path = os.path.join(cur_dir, relative_path) + if not os.path.exists(expected_path): + # Try using file_directory instead. Some of the tools have a different + # style of .cmd file than the kernel. + cur_dir = file_directory + expected_path = os.path.join(cur_dir, relative_path) + if not os.path.exists(expected_path): + raise ValueError('File %s not in %s or %s' % + (relative_path, root_directory, file_directory)) + return { + 'directory': cur_dir, + 'file': relative_path, + 'command': command_prefix + relative_path, + } + + +def main(): + """Walks through the directory and finds and parses .cmd files.""" + log_level, directory, output = parse_arguments() + + level = getattr(logging, log_level) + logging.basicConfig(format='%(levelname)s: %(message)s', level=level) + + filename_matcher = re.compile(_FILENAME_PATTERN) + line_matcher = re.compile(_LINE_PATTERN) + + compile_commands = [] + for dirpath, _, filenames in os.walk(directory): + for filename in filenames: + if not filename_matcher.match(filename): + continue + filepath = os.path.join(dirpath, filename) + + with open(filepath, 'rt') as f: + for line in f: + result = line_matcher.match(line) + if not result: + continue + + try: + entry = process_line(directory, dirpath, + result.group(1), result.group(2)) + compile_commands.append(entry) + except ValueError as err: + logging.info('Could not add line from %s: %s', + filepath, err) + + with open(output, 'wt') as f: + json.dump(compile_commands, f, indent=2, sort_keys=True) + + count = len(compile_commands) + if count < _LOW_COUNT_THRESHOLD: + logging.warning( + 'Found %s entries. Have you compiled the kernel?', count) + + +if __name__ == '__main__': + main()