gen_compile_commands: parse only the first line of .*.cmd files

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.

Masahiro Yamada committed 6 years ago

Commit 8a685db1 parent 23cd88c1 file · +2 −5Browse files

Showing the changes to scripts (1 of 1 file). Show all

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scripts/gen_compile_commands.py+2−5

             filepath = os.path.join(dirpath, filename)
             with open(filepath, 'rt') as f:
-                for line in f:
+                result = line_matcher.match(f.readline())
-                    result = line_matcher.match(line)
+                if result:
-                    if not result:
-                        continue
                     try:
                         entry = process_line(directory, dirpath,
                                              result.group(1), result.group(2))