PATCH: speed up ar(1)
Ben Elliston
bje@au1.ibm.com
Mon Mar 7 23:47:00 GMT 2005
The following patch alters the ar cache representation from a singly linked list to a
hash table using the hashtab implementation from libiberty. When archiving files
with thousands of archive members (eg. libjava), this patch results in a 15-25%
performance improvement.
Tested with an --enable-targets=all build, make check-binutils and a byte-wise
comparison of the libjava libraries built with and without a patched ar.
Okay to commit?
Index: archive.c
===================================================================
RCS file: /home/bje/src-cvs/src/bfd/archive.c,v
retrieving revision 1.34
diff -u -r1.34 archive.c
--- archive.c 3 Mar 2005 11:40:56 -0000 1.34
+++ archive.c 7 Mar 2005 22:48:34 -0000
@@ -133,6 +133,7 @@
#include "aout/ar.h"
#include "aout/ranlib.h"
#include "safe-ctype.h"
+#include "hashtab.h"
#ifndef errno
extern int errno;
@@ -146,8 +147,7 @@
to the front of the contents! */
struct ar_cache {
file_ptr ptr;
- bfd *arelt;
- struct ar_cache *next;
+ bfd *arbfd;
};
#define ar_padchar(abfd) ((abfd)->xvec->ar_pad_char)
@@ -247,14 +247,36 @@
bfd *
_bfd_look_for_bfd_in_cache (bfd *arch_bfd, file_ptr filepos)
{
- struct ar_cache *current;
+ struct ar_cache m;
+ m.ptr = filepos;
- for (current = bfd_ardata (arch_bfd)->cache; current != NULL;
- current = current->next)
- if (current->ptr == filepos)
- return current->arelt;
+ htab_t hash_table = bfd_ardata (arch_bfd)->cache;
+ if (hash_table)
+ {
+ struct ar_cache *entry = (struct ar_cache *) htab_find (hash_table, &m);
+ if (!entry)
+ return NULL;
+ else
+ return entry->arbfd;
+ }
+ else
+ return NULL;
+}
+
+static hashval_t
+hash_file_ptr (const PTR p)
+{
+ return (hashval_t) (((struct ar_cache *) p)->ptr);
+}
- return NULL;
+/* Returns non-zero if P1 and P2 are equal. */
+
+static int
+eq_file_ptr (const PTR p1, const PTR p2)
+{
+ struct ar_cache *arc1 = (struct ar_cache *) p1;
+ struct ar_cache *arc2 = (struct ar_cache *) p2;
+ return arc1->ptr == arc2->ptr;
}
/* Kind of stupid to call cons for each one, but we don't do too many. */
@@ -262,25 +284,24 @@
bfd_boolean
_bfd_add_bfd_to_archive_cache (bfd *arch_bfd, file_ptr filepos, bfd *new_elt)
{
- bfd_size_type amt = sizeof (struct ar_cache);
-
- struct ar_cache *new_cache = bfd_zalloc (arch_bfd, amt);
- if (new_cache == NULL)
- return FALSE;
+ struct ar_cache *cache;
+ htab_t hash_table = bfd_ardata (arch_bfd)->cache;
- new_cache->ptr = filepos;
- new_cache->arelt = new_elt;
- new_cache->next = NULL;
- if (bfd_ardata (arch_bfd)->cache == NULL)
- bfd_ardata (arch_bfd)->cache = new_cache;
- else
+ /* If the hash table hasn't been created, create it. */
+ if (hash_table == NULL)
{
- struct ar_cache *current = bfd_ardata (arch_bfd)->cache;
-
- while (current->next != NULL)
- current = current->next;
- current->next = new_cache;
+ hash_table = htab_create_alloc (16, hash_file_ptr, eq_file_ptr,
+ NULL, calloc, free);
+ if (hash_table == NULL)
+ return FALSE;
+ bfd_ardata (arch_bfd)->cache = hash_table;
}
+
+ /* Insert new_elt into the hash table by filepos. */
+ cache = bfd_zalloc (arch_bfd, sizeof (struct ar_cache));
+ cache->ptr = filepos;
+ cache->arbfd = new_elt;
+ *htab_find_slot (hash_table, (const void *) cache, INSERT) = cache;
return TRUE;
}
Index: libbfd-in.h
===================================================================
RCS file: /home/bje/src-cvs/src/bfd/libbfd-in.h,v
retrieving revision 1.46
diff -u -r1.46 libbfd-in.h
--- libbfd-in.h 20 Feb 2005 14:59:07 -0000 1.46
+++ libbfd-in.h 7 Mar 2005 22:48:34 -0000
@@ -23,6 +23,8 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+#include "hashtab.h"
+
/* Align an address upward to a boundary, expressed as a number of bytes.
E.g. align to an 8-byte boundary with argument of 8. Take care never
to wrap around if the address is within boundary-1 of the end of the
@@ -57,7 +59,7 @@
struct artdata {
file_ptr first_file_filepos;
/* Speed up searching the armap */
- struct ar_cache *cache;
+ htab_t cache;
bfd *archive_head; /* Only interesting in output routines */
carsym *symdefs; /* the symdef entries */
symindex symdef_count; /* how many there are */
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