[PATCH] checkpatch: Prefer static const declarations

From: Joe Perches
Date: Mon Oct 19 2020 - 15:19:08 EST


There are about 100,000 uses of 'static const <type>' but about
400 uses
of 'static <type> const' in the kernel where type is
not a pointer.

The kernel almost always uses "static const" over "const static"
as there is a compiler warning for that declaration style.

But there is no compiler warning for "static <type> const".

So add a checkpatch warning for the atypical declaration uses of.

const static <type> <foo>
and
static <type> const <foo>

For example:

$ ./scripts/checkpatch.pl -f --emacs --quiet --nosummary -types=static_const arch/arm/crypto/aes-ce-glue.c
arch/arm/crypto/aes-ce-glue.c:75: WARNING: Move const after static - use 'static const u8'
#75: FILE: arch/arm/crypto/aes-ce-glue.c:75:
+ static u8 const rcon[] = {

Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
---
scripts/checkpatch.pl | 12 ++++++++++++
1 file changed, 12 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index fab38b493cef..f82ec64f4fc7 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4207,6 +4207,18 @@ sub process {
}
}

+# check for const static or static <non ptr type> const declarations
+# prefer 'static const <foo>' over 'const static <foo>' and 'static <foo> const'
+ if ($sline =~ /^\+\s*const\s+static\s+($Type)\b/ ||
+ $sline =~ /^\+\s*static\s+($BasicType)\s+const\b/) {
+ if (WARN("STATIC_CONST",
+ "Move const after static - use 'static const $1'\n" . $herecurr) &&
+ $fix) {
+ $fixed[$fixlinenr] =~ s/\bconst\s+static\b/static const/;
+ $fixed[$fixlinenr] =~ s/\bstatic\s+($BasicType)\s+const\b/static const $1/;
+ }
+ }
+
# check for non-global char *foo[] = {"bar", ...} declarations.
if ($line =~ /^.\s+(?:static\s+|const\s+)?char\s+\*\s*\w+\s*\[\s*\]\s*=\s*\{/) {
WARN("STATIC_CONST_CHAR_ARRAY",