lkml.org 
[lkml]   [2020]   [Aug]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/3] gen_compile_commands: wire up build rule to Makefile
Date
Currently, you need to explicitly run scripts/gen_compile_commands.py
to create compile_commands.json. It traverses the object tree
(you need to pass the -d option to deal with a separate output tree),
and parses all the .*.cmd file found.

If you rebuild the kernel over again without 'make clean', stale
.*.cmd files from older builds will create invalid entries in
compile_commands.json.

This commit wires up the compile_commands.json rule to the top
Makefile, and makes it parse .*.cmd files only from the current build
to avoid stale entries.

It is possible to extract only relevant .*.cmd files by checking
$(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order.
The objects or archives linked to vmlinux are listed in
$(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are
listed in modules.order.

You can create compile_commands.json from Make:

$ make -j$(nproc) CC=clang compile_commands.json

Of course, you can build vmlinux, modules, and compile_commands.json
all together in a single command:

$ make -j$(nproc) CC=clang all compile_commands.json

It works also for M= builds. In this case, compile_commands.json
is created in the top directory of the external module.

I hope this will be overall improvements, but it has a drawback;
the coverage of the compile_commands.json is reduced because only
the objects linked to vmlinux or modules are handled. For example,
the following C files are not included in compile_commands.json:

- Decompressor source files (arch/*/boot/compressed/)
- VDSO source files
- C files used to generate intermediates (e.g. kernel/bounds.c)
- standalone host programs

Here is a note for out-of-tree builds. 'make compile_commands.json'
works with O= option, but please notice compile_commands.json is
created in the object tree instead of the source tree.

Some people may want to have compile_commands.json in the source tree
because Clang Tools searches for it through all parent paths of the
first input source file.

However, you cannot do it for O= builds. Kbuild should never generate
any build artifact in the source tree when O= is given because the
source tree might be read-only. Any write attempt to the source tree
is monitored and the violation may be reported. See the commit log of
8ef14c2c41d9.

So, the only possible way it to create compile_commands.json in the
object tree, then specify '-p <build-path>' when you use clang-check,
clang-tidy, etc.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

Makefile | 29 ++++++-
scripts/gen_compile_commands.py | 146 +++++++++++++-------------------
2 files changed, 82 insertions(+), 93 deletions(-)

diff --git a/Makefile b/Makefile
index 6844b848bfec..4d65affb6917 100644
--- a/Makefile
+++ b/Makefile
@@ -634,7 +634,7 @@ endif
# in addition to whatever we do anyway.
# Just "make" or "make all" shall build modules as well

-ifneq ($(filter all modules nsdeps,$(MAKECMDGOALS)),)
+ifneq ($(filter all modules nsdeps %compile_commands.json,$(MAKECMDGOALS)),)
KBUILD_MODULES := 1
endif

@@ -1459,7 +1459,8 @@ endif # CONFIG_MODULES

# Directories & files removed with 'make clean'
CLEAN_FILES += include/ksym vmlinux.symvers \
- modules.builtin modules.builtin.modinfo modules.nsdeps
+ modules.builtin modules.builtin.modinfo modules.nsdeps \
+ compile_commands.json

# Directories & files removed with 'make mrproper'
MRPROPER_FILES += include/config include/generated \
@@ -1693,9 +1694,12 @@ KBUILD_MODULES := 1

build-dirs := $(KBUILD_EXTMOD)
PHONY += modules
-modules: descend
+modules: $(MODORDER)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost

+$(MODORDER): descend
+ @:
+
PHONY += modules_install
modules_install: _emodinst_ _emodinst_post

@@ -1709,8 +1713,12 @@ PHONY += _emodinst_post
_emodinst_post: _emodinst_
$(call cmd,depmod)

+compile_commands.json: $(extmod-prefix)compile_commands.json
+PHONY += compile_commands.json
+
clean-dirs := $(KBUILD_EXTMOD)
-clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps
+clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
+ $(KBUILD_EXTMOD)/compile_commands.json

PHONY += help
help:
@@ -1823,6 +1831,19 @@ nsdeps: export KBUILD_NSDEPS=1
nsdeps: modules
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/nsdeps

+# Clang Tooling
+# ---------------------------------------------------------------------------
+
+quiet_cmd_gen_compile_commands = GEN $@
+ cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
+
+$(extmod-prefix)compile_commands.json: scripts/gen_compile_commands.py \
+ $(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
+ $(if $(CONFIG_MODULES), $(MODORDER)) FORCE
+ $(call if_changed,gen_compile_commands)
+
+targets += $(extmod-prefix)compile_commands.json
+
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------

diff --git a/scripts/gen_compile_commands.py b/scripts/gen_compile_commands.py
index 19c7338740e7..d2ff0d982521 100755
--- a/scripts/gen_compile_commands.py
+++ b/scripts/gen_compile_commands.py
@@ -9,80 +9,49 @@

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 300 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 = 300
+import subprocess


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.
+ ar: Command used for parsing .a archives
output: Where to write the compile-commands JSON file.
+ files: Files to parse
"""
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)
+ ar_help = 'command used for parsing .a archives'
+ parser.add_argument('-a', '--ar', type=str, default='ar', help=ar_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)
+ output_help = 'output file for the compilation database'
+ parser.add_argument('-o', '--output', type=str,
+ default='compile_commands.json', 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)
+ files_help='files to parse (should be *.o, *.a, or modules.order)'
+ parser.add_argument('files', type=str, nargs='*', help=files_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
+ return args.ar, args.output, args.files


-def process_line(root_directory, file_directory, command_prefix, relative_path):
+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.
- 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.
+ file_path: The .c file from the end of the extracted command.
+ It can be either relative or absolute.

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 '$(pound)' (depending on the
@@ -90,60 +59,59 @@ def process_line(root_directory, file_directory, command_prefix, relative_path):
# by Make, so this code replaces the escaped version with '#'.
prefix = command_prefix.replace('\#', '#').replace('$(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,
+ 'directory': root_directory,
+ 'file': file_path,
+ 'command': prefix + file_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)
+ """Find and parse .cmd files for vmlinux and modules"""
+ ar, output, files = parse_arguments()
+
+ line_matcher = re.compile(r'^cmd_[^ ]*\.o := (.* )([^ ]*\.c)$')
+
+ # Collect objects compiled for vmlinux or modules
+ objects = []
+ for file in files:
+ if file.endswith('.o'):
+ # Some objects (head-y) are linked to vmlinux directly
+ objects.append(file)
+ elif file.endswith('.a'):
+ # Most of built-in objects are linked via built-in.a or lib.a.
+ # Use 'ar -t' to get the list of the contained objects.
+ objects += subprocess.check_output([ar, '-t', file]).decode().split()
+ elif file.endswith('modules.order'):
+ # modules.order lists all the modules.
+ with open(file) as f:
+ for line in f:
+ ko = line.rstrip()
+ base, ext = os.path.splitext(ko)
+ if ext != '.ko':
+ sys.exit('{}: mobule 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 mod_f:
+ objects += mod_f.readline().split()
+ else:
+ sys.exit('{}: unknown file type'.format(file))

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:
- line = f.readline()
- result = line_matcher.match(line)
- if result:
- 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)
+ cwd = os.getcwd()
+ for object in objects:
+ dir, notdir = os.path.split(object)
+ cmd_file = os.path.join(dir, '.' + notdir + '.cmd')
+ with open(cmd_file, 'rt') as f:
+ line = f.readline()
+ result = line_matcher.match(line)
+ if result:
+ entry = process_line(cwd, result.group(1), result.group(2))
+ compile_commands.append(entry)

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()
--
2.25.1
\
 
 \ /
  Last update: 2020-08-12 19:43    [W:0.122 / U:1.976 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site