linux-kernel - [PATCH 3/4] lib/vsprintf.c: Eliminate duplicate hex string array

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Date:	Sat, 21 Feb 2015 00:21:18 +0100
From:	Rasmus Villemoes <linux@...musvillemoes.dk>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Rasmus Villemoes <linux@...musvillemoes.dk>,
	"Peter Zijlstra (Intel)" <peterz@...radead.org>,
	Tejun Heo <tj@...nel.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] lib/vsprintf.c: Eliminate duplicate hex string array

gcc doesn't merge or overlap const char[] objects with identical
contents (probably language lawyers would also insist that these
things have different addresses), but there's no reason to have the
string "0123456789ABCDEF" occur in multiple places. hex_asc_upper is
declared in kernel.h and defined in lib/hexdump.c, which is
unconditionally compiled in.

Signed-off-by: Rasmus Villemoes <linux@...musvillemoes.dk>
---
 lib/vsprintf.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 98f1ce907d3d..7a299d43987a 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -383,9 +383,6 @@ static noinline_for_stack
 char *number(char *buf, char *end, unsigned long long num,
 	     struct printf_spec spec)
 {
-	/* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
-	static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
-
 	char tmp[3 * sizeof(num)];
 	char sign;
 	char locase;
@@ -422,7 +419,7 @@ char *number(char *buf, char *end, unsigned long long num,
 	/* generate full string in tmp[], in reverse order */
 	i = 0;
 	if (num < spec.base)
-		tmp[i++] = digits[num] | locase;
+		tmp[i++] = hex_asc_upper[num] | locase;
 	else if (spec.base != 10) { /* 8 or 16 */
 		int mask = spec.base - 1;
 		int shift = 3;
@@ -430,7 +427,7 @@ char *number(char *buf, char *end, unsigned long long num,
 		if (spec.base == 16)
 			shift = 4;
 		do {
-			tmp[i++] = (digits[((unsigned char)num) & mask] | locase);
+			tmp[i++] = (hex_asc_upper[((unsigned char)num) & mask] | locase);
 			num >>= shift;
 		} while (num);
 	} else { /* base 10 */
-- 
2.1.3

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