diff mbox series

[v2,1/9] gen_compile_commands: parse only the first line of .*.cmd files

Message ID 20200821190159.1033740-2-masahiroy@kernel.org (mailing list archive)
State New, archived
Headers show
Series kbuild: clang-tidy | expand

Commit Message

Masahiro Yamada Aug. 21, 2020, 7:01 p.m. UTC 
After the allmodconfig build, this script takes about 5 sec on my
machine. Most of the run-time is consumed for needless regex matching.

We know the format of .*.cmd file; the first line is the build command.
There is no need to parse the rest.

With this optimization, now it runs 4 times faster.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
---

Changes in v2:
  - Remove the unneeded variable 'line'

 scripts/gen_compile_commands.py | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/scripts/gen_compile_commands.py b/scripts/gen_compile_commands.py
index c458696ef3a7..1bcf33a93cb9 100755
--- a/scripts/gen_compile_commands.py
+++ b/scripts/gen_compile_commands.py
@@ -125,11 +125,8 @@  def main():
             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
-
+                result = line_matcher.match(f.readline())
+                if result:
                     try:
                         entry = process_line(directory, dirpath,
                                              result.group(1), result.group(2))