From 6499394c780c80b92e73498f13ce9b4a624df437 Mon Sep 17 00:00:00 2001
From: Bill Meier <wmeier@newsguy.com>
Date: Sun, 30 Jun 2013 23:03:20 +0000
Subject: Declare slist[] as static (reduces storage & code executed: *See
 below); Declare dlist[] similarly to slist[] (not really needed since
 generated storage/code was OK as is)

*On Windows the following program generates sub-optimal code
 (when built using VC10 or VC11 with CFLAGS as used when building Wireshark).

void foo(void) {
    const char *const zz[] = {"ABC", "abc"};
}
-------------

Code generated:

<snip>
_DATA	SEGMENT
$SG1013	DB	'ABC', 00H  !!! note string stored twice !!
$SG1014	DB	'ABC', 00H
$SG1015	DB	'abc', 00H
$SG1016	DB	'abc', 00H
_DATA	ENDS

<snip>
; 1    : void foo(void) {

	push	ebp
	mov	ebp, esp
	sub	esp, 8

; 2    :     const char *const zz[] = {"ABC", "abc"};

	mov	DWORD PTR _zz$[ebp], OFFSET $SG1014    !! note: each ptr of array
	mov	DWORD PTR _zz$[ebp+4], OFFSET $SG1016  !!  individually pushed on stack

<snip>

Not shown: Declaring zz as 'static' generates much better code....


svn path=/trunk/; revision=50271
---
 epan/column.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'epan')

diff --git a/epan/column.c b/epan/column.c
index e25252b54c..cef7241778 100644
--- a/epan/column.c
+++ b/epan/column.c
@@ -43,7 +43,7 @@
    string */
 const gchar *
 col_format_to_string(const gint fmt) {
-  const gchar *slist[] = {
+  static const gchar *const slist[NUM_COL_FMTS] = {
     "%q",                                       /* 0) COL_8021Q_VLAN_ID */
     "%Yt",                                      /* 1) COL_ABS_DATE_TIME */
     "%At",                                      /* 2) COL_ABS_TIME */
@@ -115,7 +115,9 @@ col_format_to_string(const gint fmt) {
 
 /* Given a format number (as defined in column_info.h), returns its
   description */
-static const gchar *dlist[NUM_COL_FMTS] = {
+const gchar *
+col_format_desc(const gint fmt) {
+  static const gchar *const dlist[NUM_COL_FMTS] = {
     "802.1Q VLAN id",                           /* 0) COL_8021Q_VLAN_ID */
     "Absolute date and time",                   /* 1) COL_ABS_DATE_TIME */
     "Absolute time",                            /* 2) COL_ABS_TIME */
@@ -177,10 +179,8 @@ static const gchar *dlist[NUM_COL_FMTS] = {
     "UTC date and time",                        /* 58) COL_UTC_DATE_TIME */
     "UTC time",                                 /* 59) COL_UTC_TIME */
     "Time (format as specified)"                /* 60) COL_CLS_TIME */
-};
+  };
 
-const gchar *
-col_format_desc(const gint fmt) {
   g_assert((fmt >= 0) && (fmt < NUM_COL_FMTS));
   return(dlist[fmt]);
 }
-- 
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