X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gas%2Fsb.c;h=76d555e34024d2fe40ba2db28535479ff135fa4a;hb=134c0c8bf4a258ba10e72b724eadf40f731bb7ec;hp=f345fe13a9a95a8f9fe870ecbe37697a4ef53eba;hpb=39a45edc073226e748566b497c216830cec119c4;p=deliverable%2Fbinutils-gdb.git

diff --git a/gas/sb.c b/gas/sb.c
index f345fe13a9..76d555e340 100644
--- a/gas/sb.c
+++ b/gas/sb.c
@@ -1,6 +1,5 @@
 /* sb.c - string buffer manipulation routines
-   Copyright 1994, 1995, 2000, 2003, 2005, 2006, 2007, 2009, 2012
-   Free Software Foundation, Inc.
+   Copyright (C) 1994-2016 Free Software Foundation, Inc.
 
    Written by Steve and Judy Chamberlain of Cygnus Support,
       sac@cygnus.com
@@ -25,6 +24,13 @@
 #include "as.h"
 #include "sb.h"
 
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+
 /* These routines are about manipulating strings.
 
    They are managed in things called `sb's which is an abbreviation
@@ -39,15 +45,21 @@
    use foo->ptr[*];
    sb_kill (&foo);  */
 
-static size_t dsize = 32;
+/* Buffers start at INIT_ALLOC size, and roughly double each time we
+   go over the current allocation.  MALLOC_OVERHEAD is a guess at the
+   system malloc overhead.  We aim to not waste any memory in the
+   underlying page/chunk allocated by the system malloc.  */
+#define MALLOC_OVERHEAD (2 * sizeof (size_t))
+#define INIT_ALLOC (64 - MALLOC_OVERHEAD - 1)
+
 static void sb_check (sb *, size_t);
 
 /* Initializes an sb.  */
 
-static void
+void
 sb_build (sb *ptr, size_t size)
 {
-  ptr->ptr = xmalloc (size + 1);
+  ptr->ptr = XNEWVEC (char, size + 1);
   ptr->max = size;
   ptr->len = 0;
 }
@@ -55,7 +67,7 @@ sb_build (sb *ptr, size_t size)
 void
 sb_new (sb *ptr)
 {
-  sb_build (ptr, dsize);
+  sb_build (ptr, INIT_ALLOC);
 }
 
 /* Deallocate the sb at ptr.  */
@@ -100,7 +112,7 @@ sb_scrub_and_add_sb (sb *ptr, sb *s)
 {
   sb_to_scrub = s;
   scrub_position = s->ptr;
-  
+
   sb_check (ptr, s->len);
   ptr->len += do_scrub_chars (scrub_from_sb, ptr->ptr + ptr->len, s->len);
 
@@ -114,18 +126,28 @@ sb_scrub_and_add_sb (sb *ptr, sb *s)
 static void
 sb_check (sb *ptr, size_t len)
 {
-  size_t max = ptr->max;
+  size_t want = ptr->len + len;
 
-  while (ptr->len + len >= max)
+  if (want > ptr->max)
     {
-      max <<= 1;
-      if (max == 0)
+      size_t max;
+
+      want += MALLOC_OVERHEAD + 1;
+      if ((ssize_t) want < 0)
 	as_fatal ("string buffer overflow");
-    }
-  if (max != ptr->max)
-    {
+#if GCC_VERSION >= 3004
+      max = (size_t) 1 << (CHAR_BIT * sizeof (want)
+			   - (sizeof (want) <= sizeof (long)
+			      ? __builtin_clzl ((long) want)
+			      : __builtin_clzll ((long long) want)));
+#else
+      max = 128;
+      while (want > max)
+	max <<= 1;
+#endif
+      max -= MALLOC_OVERHEAD + 1;
       ptr->max = max;
-      ptr->ptr = xrealloc (ptr->ptr, max + 1);
+      ptr->ptr = XRESIZEVEC (char, ptr->ptr, max + 1);
     }
 }
 
@@ -167,13 +189,12 @@ sb_add_buffer (sb *ptr, const char *s, size_t len)
   ptr->len += len;
 }
 
-/* Like sb_name, but don't include the null byte in the string.  */
+/* Write terminating NUL and return string.  */
 
 char *
 sb_terminate (sb *in)
 {
-  sb_add_char (in, 0);
-  --in->len;
+  in->ptr[in->len] = 0;
   return in->ptr;
 }