Re: [PATCH v3 07/10] gen_compile_commands: support *.o, *.a, modules.order in positional argument

Nick Desaulniers
2020-08-23T00:40:47Z

On Sat, Aug 22, 2020 at 7:56 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
> This script currently searches the specified directory for .cmd files.
> One drawback is it may contain stale .cmd files after you rebuild the
> kernel several times without 'make clean'.
>
> This commit supports *.o, *.a, and modules.order as positional
> parameters. If such files are given, they are parsed to collect
> associated .cmd files. I added a generator helper for each of them.
>
> This feature is useful to get the list of active .cmd files from the
> last build, and will be used by the next commit to wire up the
> compile_commands.json rule to the Makefile.
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> ---
>
> Changes in v3:
> - Use 'llvm-ar' instead of 'ar' for the default of -a option
> - Fix the corrupted comment block
>
> Changes in v2:
> - Separate the file parser into generator functions
> - Use 'obj' instead of 'object' because 'object' is a built-in function
> - I think using 'file' is OK because it is not a built-in function in Python3
> (https://docs.python.org/3/library/functions.html)
> Anyway, the variable 'file' is no longer used in this version
> - Keep the previous work-flow to allow to search the given directory
>
> scripts/gen_compile_commands.py | 100 ++++++++++++++++++++++++++++++--
> 1 file changed, 96 insertions(+), 4 deletions(-)
>
> diff --git a/scripts/gen_compile_commands.py b/scripts/gen_compile_commands.py
> index e45f17be8817..f370375b2f70 100755
> --- a/scripts/gen_compile_commands.py
> +++ b/scripts/gen_compile_commands.py
> @@ -12,6 +12,7 @@ import json
> import logging
> import os
> import re
> +import subprocess
>
> _DEFAULT_OUTPUT = 'compile_commands.json'
> _DEFAULT_LOG_LEVEL = 'WARNING'
> @@ -32,8 +33,9 @@ def parse_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 directories to handle to find .cmd files.
> + 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)
> @@ -53,12 +55,21 @@ def parse_arguments():
> 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.directory])
> + args.ar,
> + args.paths if len(args.paths) > 0 else [args.directory])
>
>
> def cmdfiles_in_dir(directory):
> @@ -81,6 +92,73 @@ def cmdfiles_in_dir(directory):
> 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.
>
> @@ -117,7 +195,7 @@ def process_line(root_directory, command_prefix, file_path):
>
> def main():
> """Walks through the directory and finds and parses .cmd files."""
> - log_level, directory, output, paths = parse_arguments()
> + log_level, directory, output, ar, paths = parse_arguments()
>
> level = getattr(logging, log_level)
> logging.basicConfig(format='%(levelname)s: %(message)s', level=level)
> @@ -127,7 +205,21 @@ def main():
> compile_commands = []
>
> for path in paths:
> - cmdfiles = cmdfiles_in_dir(path)
> + # 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:
> --
> 2.25.1
>

--
Thanks,
~Nick Desaulniers