Macros with flow control statements (goto and return) are
not very nice to read as any flow movement is unexpected.
Try to highlight them and emit a warning on their definition.
Avoid warning on macros that use argument concatenation as
those macros commonly create another function where the
concatenation is used in the function name definition like:
#define FOO_FUNC(name, rtn_type) \
rtn_type func##name(arg1, ...) \
{ \
rtn_type rtn; \
[code...] \
return rtn; \
}
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
> 460 #define OBD_CHECK_DT_OP(obd, op, err) \
> 461 do { \
> 462 if (!OBT(obd) || !OBP((obd), op)) { \
> 463 if (err) \
> 464 CERROR("obd_" #op ": dev %d no operation\n", \
> 465 obd->obd_minor); \
> 466 return err; \
> 467 } \
> 468 } while (0)
>
> Wow! What a terrible macro! None of the '\' are in a line. There is
> a hidden return statement in it which is a terrible thing and flow
> control statements are not allowed inside macros.
scripts/checkpatch.pl | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index da7b2d4..dc5434a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4071,12 +4071,17 @@ sub process {
my $cnt = $realcnt;
my ($off, $dstat, $dcond, $rest);
my $ctx = '';
+ my $has_flow_statement = 0;
+ my $has_arg_concat = 0;
($dstat, $dcond, $ln, $cnt, $off) =
ctx_statement_block($linenr, $realcnt, 0);
$ctx = $dstat;
#print "dstat<$dstat> dcond<$dcond> cnt<$cnt> off<$off>\n";
#print "LINE<$lines[$ln-1]> len<" . length($lines[$ln-1]) . "\n";
+ $has_flow_statement = 1 if ($ctx =~ /\b(goto|return)\b/);
+ $has_arg_concat = 1 if ($ctx =~ /\#\#/);
+
$dstat =~ s/^.\s*\#\s*define\s+$Ident(?:\([^\)]*\))?\s*//;
$dstat =~ s/$;//g;
$dstat =~ s/\\\n.//g;
@@ -4141,6 +4146,19 @@ sub process {
}
}
+# check for macros with flow control, but without ## concatenation
+# ## concatenation is commonly a macro that defines a function so ignore those
+ if ($has_flow_statement && !$has_arg_concat) {
+ my $herectx = $here . "\n";
+ my $cnt = statement_rawlines($ctx);
+
+ for (my $n = 0; $n < $cnt; $n++) {
+ $herectx .= raw_line($linenr, $n) . "\n";
+ }
+ WARN("MACRO_WITH_FLOW_CONTROL",
+ "Macros with flow control statements should be avoided\n" . "$herectx");
+ }
+
# check for line continuations outside of #defines, preprocessor #, and asm
} else {
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