From patchwork Tue Dec 18 22:49:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tom Roeder X-Patchwork-Id: 10736457 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 172806C2 for ; Tue, 18 Dec 2018 22:49:27 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F062A2B06F for ; Tue, 18 Dec 2018 22:49:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E3DC92B07B; Tue, 18 Dec 2018 22:49:26 +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 208FF2B06F for ; Tue, 18 Dec 2018 22:49:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727104AbeLRWtZ (ORCPT ); Tue, 18 Dec 2018 17:49:25 -0500 Received: from mail-qk1-f202.google.com ([209.85.222.202]:49319 "EHLO mail-qk1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726744AbeLRWtZ (ORCPT ); Tue, 18 Dec 2018 17:49:25 -0500 Received: by mail-qk1-f202.google.com with SMTP id a193so21051781qkg.16 for ; Tue, 18 Dec 2018 14:49:24 -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=W598n4mnM++cMEbV872C6rFTbynDkEctoaLA1YpB59k=; b=p6lA1K3P2Qb1TVXldBAlgKJdNAZhlRlC7yrYCcyvFVUJ3iVOpSfxFKYWWbcSfkyr8T TE1eKdEmKS0wSUR27tsk2eBdFgHBnHjFgec/SLXvaXJuVLedrTTojo//5castU7+Jsrk QBkxaJtqi1IrfvbQNlrOIxM9so/RTzXXGCLitNUqF5w81pQ1LIRmrVp08iaGvuyAvRmk Etj5ckCevBeBJVx3+K0t/ZYn91LoSaaEVB9xJHoh6l4HCd1Ol965b30OfRP/UBGYDRYd 6ag6nAM7FLnk+10cPr5eeyRu+Mn9BhwjBqA0zOD8B46x0C260V/zn0frgEVVqiEG51/X pMjw== 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=W598n4mnM++cMEbV872C6rFTbynDkEctoaLA1YpB59k=; b=HPSCqWEgrj+9iZCsiZe6XFVQMkFVbGHzytThlmmPvJ5KkLKyFMqOizeKxVy84Z97qr A0W8bmWJuK/IL6td4wBtCKcosfTOhrO8zWLV2xRsBqJ+Ct1+NuwyQacsgulBQXtboJF5 BR8HKOkXsSMqdvLgMh+Relv03Sbn2tZk4gGu952medNLFeb5Ko5ngBAxm/HKqOYRfX++ 4rd0O2+V+nw3+EDv5636n6JnQlWNv5n83B0HmXz0rFALvo5WrU/cG+tje7l8tagsjIyz Y80ag0FFGRLu4PSsQWVxRNFLM2zscuBh1KEpMewR4Qpxu5fu9va+cdNef8gZ0M7Xr81p 4V7Q== X-Gm-Message-State: AA+aEWaTA4ivgf+6TZG9XYSm3cuG9m9mHg+oDZV3Yy2ZTRKFkTEfhJWs xXI2w71eIzU5aPjgyQwyWsc4dhhciFvhHA== X-Google-Smtp-Source: AFSGD/WDoCaw4alzYoyMAaWLPypL4O5bE7t70F4/huxPu4qXN5ZJfaVu44dXF3js/Fj4wEdv0C5q1DxC++mU6A== X-Received: by 2002:a37:a315:: with SMTP id m21mr18535785qke.30.1545173363974; Tue, 18 Dec 2018 14:49:23 -0800 (PST) Date: Tue, 18 Dec 2018 14:49:07 -0800 Message-Id: <20181218224907.1274-1-tmroeder@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.20.0.405.gbc1bbc6f85-goog Subject: [PATCH v2] scripts: add a tool to produce a compile_commands.json file From: Tom Roeder To: Masahiro Yamada Cc: Michal Marek , 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 --- Changelog since v1: - Add simple string replacement to unescape the pound sign. scripts/gen_compile_commands.py | 151 ++++++++++++++++++++++++++++++++ 1 file changed, 151 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..7915823b92a5 --- /dev/null +++ b/scripts/gen_compile_commands.py @@ -0,0 +1,151 @@ +#!/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. + """ + # The .cmd files are intended to be included directly by Make, so they + # escape the pound sign '#', either as '\#' or '$(pound)' (depending on the + # kernel version). The compile_commands.json file is not interepreted + # by Make, so this code replaces the escaped version with '#'. + prefix = command_prefix.replace('\#', '#').replace('$(pound)', '#') + + 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': 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()