linux-kernel - [PATCH] checkpatch: Warn on const char foo[] = "bar"; declarations

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Date:   Sun, 04 Nov 2018 13:52:04 -0800
From:   Joe Perches <joe@...ches.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Whitcroft <apw@...onical.com>
Cc:     Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] checkpatch: Warn on const char foo[]  = "bar"; declarations

These declarations should generally be static const to avoid
poor compilation and runtime performance where compilers
tend to initialize the const declaration for every call
instead of using .rodata for the string.

Miscellanea:

o Convert spaces to tabs for indentation in 2 adjacent checks

Signed-off-by: Joe Perches <joe@...ches.com>
---
 scripts/checkpatch.pl | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index c883ec55654f..7789e13dac9d 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3869,14 +3869,23 @@ sub process {
 			WARN("STATIC_CONST_CHAR_ARRAY",
 			     "static const char * array should probably be static const char * const\n" .
 				$herecurr);
-               }
+		}
+
+# check for initialized const char arrays that should be static const
+		if ($line =~ /^\+\s*const\s+(char|unsigned\s+char|_*u8|(?:[us]_)?int8_t)\s+\w+\s*\[\s*(?:\w+\s*)?\]\s*=\s*"/) {
+			if (WARN("STATIC_CONST_CHAR_ARRAY",
+				 "const array should probably be static const\n" . $herecurr) &&
+			    $fix) {
+				$fixed[$fixlinenr] =~ s/(^.\s*)const\b/${1}static const/;
+			}
+		}
 
 # check for static char foo[] = "bar" declarations.
 		if ($line =~ /\bstatic\s+char\s+(\w+)\s*\[\s*\]\s*=\s*"/) {
 			WARN("STATIC_CONST_CHAR_ARRAY",
 			     "static char array declaration should probably be static const char\n" .
 				$herecurr);
-               }
+		}
 
 # check for const <foo> const where <foo> is not a pointer or array type
 		if ($sline =~ /\bconst\s+($BasicType)\s+const\b/) {