[PATCH v2 2/2] checkpatch: 3 use-cases for --debug rx=1 option

From: Jim Cromie
Date: Sun Oct 26 2025 - 16:29:46 EST


Use the drx_print() helper in 3 cases inside code which counts macro
arg expansions.

$ scripts/checkpatch.pl --strict patch-1 --debug rx='##'
drx_print: 'arg ##' catenations
>> Matched (`$&`): <_id##>
drx_print: 'arg ##' catenations
>> Matched (`$&`): <_id##>
drx_print: '#|## arg' catenations
>> Matched (`$&`): <##_model>
drx_print: '#|## arg' catenations
>> Matched (`$&`): <##_model>

$ scripts/checkpatch.pl --strict patch-1 --debug rx='insp'
drx_print: -arg-inspections-
>> Matched (`$&`): <__builtin_constant_p(cls>
>> Capture 1 (`$1`): <__builtin_constant_p>

NB: see also the extended --debug key=1 facility:

$ scripts/checkpatch.pl --strict ../linux.git/pt-1 --debug foo=1
Unknown debug key 'foo', expecting: 'values possible type attr rx'

NB: I moved the 2 #|## strippers above the more complex macro, because
the latter caught one ## case that it needn't have.

Signed-off-by: Jim Cromie <jim.cromie@xxxxxxxxx>
---
scripts/checkpatch.pl | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c174e3bef2b2..240ddab17d89 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6078,9 +6078,17 @@ sub process {
next if ($arg =~ /\.\.\./);
next if ($arg =~ /^type$/i);
my $tmp_stmt = $define_stmt;
- $tmp_stmt =~ s/\b(__must_be_array|offsetof|sizeof|sizeof_field|__stringify|typeof|__typeof__|__builtin\w+|typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b//g;
- $tmp_stmt =~ s/\#+\s*$arg\b//g;
- $tmp_stmt =~ s/\b$arg\s*\#\#//g;
+
+ $tmp_stmt =~ s/\#+\s*$arg\b/drx_print("'#|## arg' catenations")/ge;
+ $tmp_stmt =~ s/\b$arg\s*\#\#/drx_print("'arg ##' catenations");/ge;
+ $tmp_stmt =~ s{
+ \b(__must_be_array|offsetof|sizeof|sizeof_field|
+ __stringify|typeof|__typeof__|__builtin\w+|
+ typecheck\s*\(\s*$Type\s*,|\#+)\s*\(*\s*$arg\s*\)*\b }
+ {
+ drx_print("-arg-inspections-");
+ }xge;
+
my $use_cnt = () = $tmp_stmt =~ /\b$arg\b/g;
if ($use_cnt > 1) {
CHK("MACRO_ARG_REUSE",
--
2.51.0