From 938224b5e596c1c30d968ffd927a578ea7c4f45b Mon Sep 17 00:00:00 2001 From: Joe Perches Date: Wed, 20 Jan 2016 14:59:15 -0800 Subject: [PATCH] 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 Suggested-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/checkpatch.pl | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index c7bf1aa2eeb3..86457062db29 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -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",