checkpatch: warn when casting constants to c90 int or longer types
Linus Torvalds wrote:
> I can't but help to react that this:
> #define IOMMU_ERROR_CODE (~(unsigned long) 0)
> Not that this *matters*, but it's a bit odd to have to cast constants
> to perfectly regular C types.
So add a test that looks for constants that are cast to
standard C90 int or longer types and suggest using C90
"6.4.4.1 Integer constants" integer-suffixes instead.
Miscellanea:
o Add a --fix option too
Signed-off-by: Joe Perches <joe@perches.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
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 c7bf1aa..8645706 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -433,6 +433,28 @@
qr{${Ident}_handler_fn},
@typeListMisordered,
);
+
+our $C90_int_types = qr{(?x:
+ long\s+long\s+int\s+(?:un)?signed|
+ long\s+long\s+(?:un)?signed\s+int|
+ long\s+long\s+(?:un)?signed|
+ (?:(?:un)?signed\s+)?long\s+long\s+int|
+ (?:(?:un)?signed\s+)?long\s+long|
+ int\s+long\s+long\s+(?:un)?signed|
+ int\s+(?:(?:un)?signed\s+)?long\s+long|
+
+ long\s+int\s+(?:un)?signed|
+ long\s+(?:un)?signed\s+int|
+ long\s+(?:un)?signed|
+ (?:(?:un)?signed\s+)?long\s+int|
+ (?:(?:un)?signed\s+)?long|
+ int\s+long\s+(?:un)?signed|
+ int\s+(?:(?:un)?signed\s+)?long|
+
+ int\s+(?:un)?signed|
+ (?:(?:un)?signed\s+)?int
+)};
+
our @typeListFile = ();
our @typeListWithAttr = (
@typeList,
@@ -5272,6 +5294,26 @@
}
}
+# check for cast of C90 native int or longer types constants
+ if ($line =~ /(\(\s*$C90_int_types\s*\)\s*)($Constant)\b/) {
+ my $cast = $1;
+ my $const = $2;
+ if (WARN("TYPECAST_INT_CONSTANT",
+ "Unnecessary typecast of c90 int constant\n" . $herecurr) &&
+ $fix) {
+ my $suffix = "";
+ my $newconst = $const;
+ $newconst =~ s/${Int_type}$//;
+ $suffix .= 'U' if ($cast =~ /\bunsigned\b/);
+ if ($cast =~ /\blong\s+long\b/) {
+ $suffix .= 'LL';
+ } elsif ($cast =~ /\blong\b/) {
+ $suffix .= 'L';
+ }
+ $fixed[$fixlinenr] =~ s/\Q$cast\E$const\b/$newconst$suffix/;
+ }
+ }
+
# check for sizeof(&)
if ($line =~ /\bsizeof\s*\(\s*\&/) {
WARN("SIZEOF_ADDRESS",