Re: [PATCH] checkpatch: Add --strict test for function pointer calling style

From: Peter Hurley
Date: Wed Nov 05 2014 - 14:13:06 EST


On 11/05/2014 01:41 PM, Joe Perches wrote:
> Peter Hurley wrote:
>
> The use of older function ptr calling style, (*fn)(), makes static
> analysis more error-prone; replace with modern fn() style.
>
> So make checkpatch emit a --strict test for that condition.
>
> Update the unnecessary parentheses test for dereferencing
> objects at the same time and create a $fix mechanism too.

Cool.

perl's not my thing; how does it know not to trip up on

initcall_t *call;

(*call)();

[which I verified it properly does not flag in drivers/tty/tty_io.c]

Regards,
Peter Hurley


> Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
> ---
> scripts/checkpatch.pl | 24 +++++++++++++++++++++---
> 1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 24d6702..552e5dd 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3838,9 +3838,27 @@ sub process {
> # ie: &(foo->bar) should be &foo->bar and *(foo->bar) should be *foo->bar
>
> while ($line =~ /(?:[^&]&\s*|\*)\(\s*($Ident\s*(?:$Member\s*)+)\s*\)/g) {
> - CHK("UNNECESSARY_PARENTHESES",
> - "Unnecessary parentheses around $1\n" . $herecurr);
> - }
> + my $var = $1;
> + if (CHK("UNNECESSARY_PARENTHESES",
> + "Unnecessary parentheses around $var\n" . $herecurr) &&
> + $fix) {
> + $fixed[$fixlinenr] =~ s/\(\s*\Q$var\E\s*\)/$var/;
> + }
> + }
> +
> +# check for unnecessary parentheses around function pointer uses
> +# ie: (foo->bar)(); should be foo->bar();
> +# but not "if (foo->bar) (" to avoid some false positives
> + if ($line =~ /(\bif\s*|)(\(\s*$Ident\s*(?:$Member\s*)+\))[ \t]*\(/ && $1 !~ /^if/) {
> + my $var = $2;
> + if (CHK("UNNECESSARY_PARENTHESES",
> + "Unnecessary parentheses around function pointer $var\n" . $herecurr) &&
> + $fix) {
> + my $var2 = deparenthesize($var);
> + $var2 =~ s/\s//g;
> + $fixed[$fixlinenr] =~ s/\Q$var\E/$var2/;
> + }
> + }
>
> #goto labels aren't indented, allow a single space however
> if ($line=~/^.\s+[A-Za-z\d_]+:(?![0-9]+)/ and
>
>

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