Re: [PATCH] Kbuild: add compile_commands.json target

[Sascha Hauer <sha@pengutronix.de>]

On Sun, Jan 31, 2021 at 08:40:04PM +0100, Ahmad Fatoum wrote:
> The JSON compilation database format specification describes a
> compile_commands.json file that lists how translation units are
> compiled by a build system. This makes integration of external tools,
> like IDEs, LSP servers and static analyzers easier.
> 
> Import the Linux bits. The database can now be manually generated
> with make compile_commands.json.
> 
> Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
> ---
> Cc: Rouven Czerwinski <rcz@pengutronix.de>
> ---

Applied, thanks

Sascha

>  .gitignore                                  |   1 +
>  Makefile                                    |  16 +-
>  scripts/clang-tools/gen_compile_commands.py | 237 ++++++++++++++++++++
>  3 files changed, 252 insertions(+), 2 deletions(-)
>  create mode 100755 scripts/clang-tools/gen_compile_commands.py
> 
> diff --git a/.gitignore b/.gitignore
> index 7fa2948bf4a4..d7a37b3c9b39 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -87,3 +87,4 @@ GTAGS
>  /allno.config
>  /allrandom.config
>  /allyes.config
> +/compile_commands.json
> diff --git a/Makefile b/Makefile
> index ea1d5dae1c5e..f3c85cff9430 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -541,7 +541,7 @@ endif
>  # in addition to whatever we do anyway.
>  # Just "make" or "make all" shall build modules as well
>  
> -ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
> +ifneq ($(filter all _all modules %compile_commands.json,$(MAKECMDGOALS)),)
>    KBUILD_MODULES := 1
>  endif
>  
> @@ -1104,7 +1104,7 @@ endif # CONFIG_MODULES
>  CLEAN_DIRS  += $(MODVERDIR)
>  CLEAN_FILES +=	barebox System.map include/generated/barebox_default_env.h \
>                  .tmp_version .tmp_barebox* barebox.bin barebox.map barebox.S \
> -		.tmp_kallsyms* barebox.ldr \
> +		.tmp_kallsyms* barebox.ldr compile_commands.json \
>  		scripts/bareboxenv-target barebox-flash-image \
>  		barebox.srec barebox.s5p barebox.ubl barebox.zynq \
>  		barebox.uimage barebox.spi barebox.kwb barebox.kwbuart \
> @@ -1162,6 +1162,18 @@ distclean: mrproper
>  		-o -name 'core' \) \
>  		-type f -print | xargs rm -f
>  
> +# Clang Tooling
> +# ---------------------------------------------------------------------------
> +
> +quiet_cmd_gen_compile_commands = GEN     $@
> +      cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
> +
> +compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
> +	$(BAREBOX_OBJS) $(if $(CONFIG_PBL_IMAGE),$(BAREBOX_PBL_OBJS),) FORCE
> +	$(call if_changed,gen_compile_commands)
> +
> +PHONY += compile_commands.json
> +
>  # Brief documentation of the typical targets used
>  # ---------------------------------------------------------------------------
>  
> diff --git a/scripts/clang-tools/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
> new file mode 100755
> index 000000000000..7ed3919f453a
> --- /dev/null
> +++ b/scripts/clang-tools/gen_compile_commands.py
> @@ -0,0 +1,237 @@
> +#!/usr/bin/env python
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Copyright (C) Google LLC, 2018
> +#
> +# Author: Tom Roeder <tmroeder@google.com>
> +#
> +"""A tool for generating compile_commands.json in the Linux kernel."""
> +
> +import argparse
> +import json
> +import logging
> +import os
> +import sys
> +import re
> +import subprocess
> +
> +_DEFAULT_OUTPUT = 'compile_commands.json'
> +_DEFAULT_LOG_LEVEL = 'WARNING'
> +
> +_FILENAME_PATTERN = r'^\..*\.cmd$'
> +_LINE_PATTERN = r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$'
> +_VALID_LOG_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'ERROR', 'CRITICAL']
> +
> +
> +def parse_arguments():
> +    """Sets up and parses command-line arguments.
> +
> +    Returns:
> +        log_level: A logging level to filter log output.
> +        directory: The work directory where the objects were built.
> +        ar: Command used for parsing .a archives.
> +        output: Where to write the compile-commands JSON file.
> +        paths: The list of files/directories to handle to find .cmd files.
> +    """
> +    usage = 'Creates a compile_commands.json database from kernel .cmd files'
> +    parser = argparse.ArgumentParser(description=usage)
> +
> +    directory_help = ('specify the output directory used for the kernel build '
> +                      '(defaults to the working directory)')
> +    parser.add_argument('-d', '--directory', type=str, default='.',
> +                        help=directory_help)
> +
> +    output_help = ('path to the output command database (defaults to ' +
> +                   _DEFAULT_OUTPUT + ')')
> +    parser.add_argument('-o', '--output', type=str, default=_DEFAULT_OUTPUT,
> +                        help=output_help)
> +
> +    log_level_help = ('the level of log messages to produce (defaults to ' +
> +                      _DEFAULT_LOG_LEVEL + ')')
> +    parser.add_argument('--log_level', choices=_VALID_LOG_LEVELS,
> +                        default=_DEFAULT_LOG_LEVEL, help=log_level_help)
> +
> +    ar_help = 'command used for parsing .a archives'
> +    parser.add_argument('-a', '--ar', type=str, default='llvm-ar', help=ar_help)
> +
> +    paths_help = ('directories to search or files to parse '
> +                  '(files should be *.o, *.a, or modules.order). '
> +                  'If nothing is specified, the current directory is searched')
> +    parser.add_argument('paths', type=str, nargs='*', help=paths_help)
> +
> +    args = parser.parse_args()
> +
> +    return (args.log_level,
> +            os.path.abspath(args.directory),
> +            args.output,
> +            args.ar,
> +            args.paths if len(args.paths) > 0 else [args.directory])
> +
> +
> +def cmdfiles_in_dir(directory):
> +    """Generate the iterator of .cmd files found under the directory.
> +
> +    Walk under the given directory, and yield every .cmd file found.
> +
> +    Args:
> +        directory: The directory to search for .cmd files.
> +
> +    Yields:
> +        The path to a .cmd file.
> +    """
> +
> +    filename_matcher = re.compile(_FILENAME_PATTERN)
> +
> +    for dirpath, _, filenames in os.walk(directory):
> +        for filename in filenames:
> +            if filename_matcher.match(filename):
> +                yield os.path.join(dirpath, filename)
> +
> +
> +def to_cmdfile(path):
> +    """Return the path of .cmd file used for the given build artifact
> +
> +    Args:
> +        Path: file path
> +
> +    Returns:
> +        The path to .cmd file
> +    """
> +    dir, base = os.path.split(path)
> +    return os.path.join(dir, '.' + base + '.cmd')
> +
> +
> +def cmdfiles_for_o(obj):
> +    """Generate the iterator of .cmd files associated with the object
> +
> +    Yield the .cmd file used to build the given object
> +
> +    Args:
> +        obj: The object path
> +
> +    Yields:
> +        The path to .cmd file
> +    """
> +    yield to_cmdfile(obj)
> +
> +
> +def cmdfiles_for_a(archive, ar):
> +    """Generate the iterator of .cmd files associated with the archive.
> +
> +    Parse the given archive, and yield every .cmd file used to build it.
> +
> +    Args:
> +        archive: The archive to parse
> +
> +    Yields:
> +        The path to every .cmd file found
> +    """
> +    for obj in subprocess.check_output([ar, '-t', archive]).decode().split():
> +        yield to_cmdfile(obj)
> +
> +
> +def cmdfiles_for_modorder(modorder):
> +    """Generate the iterator of .cmd files associated with the modules.order.
> +
> +    Parse the given modules.order, and yield every .cmd file used to build the
> +    contained modules.
> +
> +    Args:
> +        modorder: The modules.order file to parse
> +
> +    Yields:
> +        The path to every .cmd file found
> +    """
> +    with open(modorder) as f:
> +        for line in f:
> +            ko = line.rstrip()
> +            base, ext = os.path.splitext(ko)
> +            if ext != '.ko':
> +                sys.exit('{}: module path must end with .ko'.format(ko))
> +            mod = base + '.mod'
> +	    # The first line of *.mod lists the objects that compose the module.
> +            with open(mod) as m:
> +                for obj in m.readline().split():
> +                    yield to_cmdfile(obj)
> +
> +
> +def process_line(root_directory, command_prefix, file_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.
> +        command_prefix: The extracted command line, up to the last element.
> +        file_path: The .c file from the end of the extracted command.
> +            Usually relative to root_directory, but sometimes absolute.
> +
> +    Returns:
> +        An entry to append to compile_commands.
> +
> +    Raises:
> +        ValueError: Could not find the extracted file based on file_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)', '#')
> +
> +    # Use os.path.abspath() to normalize the path resolving '.' and '..' .
> +    abs_path = os.path.abspath(os.path.join(root_directory, file_path))
> +    if not os.path.exists(abs_path):
> +        raise ValueError('File %s not found' % abs_path)
> +    return {
> +        'directory': root_directory,
> +        'file': abs_path,
> +        'command': prefix + file_path,
> +    }
> +
> +
> +def main():
> +    """Walks through the directory and finds and parses .cmd files."""
> +    log_level, directory, output, ar, paths = parse_arguments()
> +
> +    level = getattr(logging, log_level)
> +    logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
> +
> +    line_matcher = re.compile(_LINE_PATTERN)
> +
> +    compile_commands = []
> +
> +    for path in paths:
> +        # If 'path' is a directory, handle all .cmd files under it.
> +        # Otherwise, handle .cmd files associated with the file.
> +        # Most of built-in objects are linked via archives (built-in.a or lib.a)
> +        # but some objects are linked to vmlinux directly.
> +        # Modules are listed in modules.order.
> +        if os.path.isdir(path):
> +            cmdfiles = cmdfiles_in_dir(path)
> +        elif path.endswith('.o'):
> +            cmdfiles = cmdfiles_for_o(path)
> +        elif path.endswith('.a'):
> +            cmdfiles = cmdfiles_for_a(path, ar)
> +        elif path.endswith('modules.order'):
> +            cmdfiles = cmdfiles_for_modorder(path)
> +        else:
> +            sys.exit('{}: unknown file type'.format(path))
> +
> +        for cmdfile in cmdfiles:
> +            with open(cmdfile, 'rt') as f:
> +                result = line_matcher.match(f.readline())
> +                if result:
> +                    try:
> +                        entry = process_line(directory, result.group(1),
> +                                             result.group(2))
> +                        compile_commands.append(entry)
> +                    except ValueError as err:
> +                        logging.info('Could not add line from %s: %s',
> +                                     cmdfile, err)
> +
> +    with open(output, 'wt') as f:
> +        json.dump(compile_commands, f, indent=2, sort_keys=True)
> +
> +
> +if __name__ == '__main__':
> +    main()
> -- 
> 2.30.0
> 
> 
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