checkpatch: reduce runtime/cpu time used
There are some cases where checkpatch can take a long time to complete.
Reduce the likelihood of this long run-time by adding a new test for lines
with and without comments and eliminating checks on lines with only
comments.
This reduces the number of "ctx_statement_block" calls, and also the
number of tests of $stat, which is now undefined for these blank lines.
One test in particular, the "check for switch/default statements without a
break", could take an extremely long time to parse as it tries to skip
interleaving comments within the ctx_statement_block/$stat and that could
be done multiple times unnecessarily.
A small test case taken from cfg80211.h before this patch would take
1000's of seconds to run, now it's just a couple seconds.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e53df2b..55277a8 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1678,6 +1678,8 @@
$linenr = 0;
foreach my $line (@lines) {
$linenr++;
+ my $sline = $line; #copy of $line
+ $sline =~ s/$;/ /g; #with comments as spaces
my $rawline = $rawlines[$linenr - 1];
@@ -2194,7 +2196,7 @@
$realline_next);
#print "LINE<$line>\n";
if ($linenr >= $suppress_statement &&
- $realcnt && $line =~ /.\s*\S/) {
+ $realcnt && $sline =~ /.\s*\S/) {
($stat, $cond, $line_nr_next, $remain_next, $off_next) =
ctx_statement_block($linenr, $realcnt, 0);
$stat =~ s/\n./\n /g;