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Commit 938224b5 authored by Joe Perches's avatar Joe Perches Committed by Linus Torvalds
Browse files

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: default avatarJoe Perches <joe@perches.com>
Suggested-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f5948701

scripts/checkpatch.pl

+42 −0
Original line number Diff line number Diff line
@@ -433,6 +433,28 @@ our @typeList = ( 
	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 @@ sub process { 
			}

		}



# 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",