On Sun, 2020-11-29 at 01:30 +0530, Dwaipayan Ray wrote:
> Modifiers %h and %hh should never be used.
Seems OK, thanks.
Acked-by: Joe Perches <j...@perches.com>
> Commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use
> of unnecessary %h[xudi] and %hh[xudi]") specifies that:
>
> "Standard integer promotion is already done and %hx and %hhx is useless
> so do not encourage the use of %hh[xudi] or %h[xudi]."
>
> "The "h" and "hh" things should never be used. The only reason for them
> being used if you have an "int", but you want to print it out as a
> "char" (and honestly, that is a really bad reason, you'd be better off
> just using a proper cast to make the code more obvious)."
>
> Add a new check to emit a warning on finding an unneeded use of %h or
> %hh modifier.
>
> Also add a fix option to the check.
>
> Link:
> https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.ca...@perches.com/
>
> Suggested-by: Joe Perches <j...@perches.com>
> Suggested-by: Lukas Bulwahn <lukas.bulw...@gmail.com>
> Signed-off-by: Dwaipayan Ray <dwaipayanr...@gmail.com>
> ---
> Changes in v4:
> - Change warning type and message
> - Use $stat_real and calculate line offset during matches
> - fix option now works for any patch line
> - # was added to format block to match %#06hh
>
> Changes in v3:
> - Change warning message
> - Fix regex match to include capture group
> - Warn on every unnecesary use of %h on a line
> - Add fix option when the format line matches current line
>
> Changes in v2:
> - Use $logFunctions instead of the manual list.
> - Relocate the check to after logging continuations check.
> - Remove perl_version_ok check
>
>
> scripts/checkpatch.pl | 22 ++++++++++++++++++++++
> 1 file changed, 22 insertions(+)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 7dc094445d83..3c86ea737e9c 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -6027,6 +6027,28 @@ sub process {
> "Avoid logging continuation uses where feasible\n"
> . $herecurr);
> }
>
> +# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions
> + if (defined $stat &&
> + $line =~ /\b$logFunctions\s*\(/ &&
> + index($stat, '"') >= 0) {
> + my $lc = $stat =~ tr@\n@@;
> + $lc = $lc + $linenr;
> + my $stat_real = get_stat_real($linenr, $lc);
> + pos($stat_real) = index($stat_real, '"');
> + while ($stat_real =~
> /[^\"%]*(%[\#\d\.\*\-]*(h+)[idux])/g) {
> + my $pspec = $1;
> + my $h = $2;
> + my $lineoff = substr($stat_real, 0, $-[1]) =~
> tr@\n@@;
> + if (WARN("UNNECESSARY_MODIFIER",
> + "Integer promotion: Using '$h' in
> '$pspec' is unnecessary\n" . "$here\n$stat_real\n") &&
> + $fix && $fixed[$fixlinenr + $lineoff] =~
> /^\+/) {
> + my $nspec = $pspec;
> + $nspec =~ s/h//g;
> + $fixed[$fixlinenr + $lineoff] =~
> s/\Q$pspec\E/$nspec/;
> + }
> + }
> + }
> +
> # check for mask then right shift without a parentheses
> if ($perl_version_ok &&
> $line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ &&
