/* hash.c -- gas hash table code
Copyright 1987, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,
- 2000, 2001, 2002, 2003
+ 2000, 2001, 2002, 2003, 2005, 2007, 2008
Free Software Foundation, Inc.
This file is part of GAS, the GNU Assembler.
GAS is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
+ the Free Software Foundation; either version 3, or (at your option)
any later version.
GAS is distributed in the hope that it will be useful,
You should have received a copy of the GNU General Public License
along with GAS; see the file COPYING. If not, write to the Free
- Software Foundation, 59 Temple Place - Suite 330, Boston, MA
- 02111-1307, USA. */
+ Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
+ 02110-1301, USA. */
/* This version of the hash table code is a wholescale replacement of
the old hash table code, which was fairly bad. This is based on
#include "safe-ctype.h"
#include "obstack.h"
-/* The default number of entries to use when creating a hash table. */
-
-#define DEFAULT_SIZE (4051)
-
/* An entry in a hash table. */
struct hash_entry {
table. */
unsigned long hash;
/* Pointer being stored in the hash table. */
- PTR data;
+ void *data;
};
/* A hash table. */
#endif /* HASH_STATISTICS */
};
+/* The default number of entries to use when creating a hash table.
+ Note this value can be reduced to 4051 by using the command line
+ switch --reduce-memory-overheads, or set to other values by using
+ the --hash-size=<NUMBER> switch. */
+
+static unsigned long gas_hash_table_size = 65537;
+
+void
+set_gas_hash_table_size (unsigned long size)
+{
+ gas_hash_table_size = size;
+}
+
+/* FIXME: This function should be amalgmated with bfd/hash.c:bfd_hash_set_default_size(). */
+static unsigned long
+get_gas_hash_table_size (void)
+{
+ /* Extend this prime list if you want more granularity of hash table size. */
+ static const unsigned long hash_size_primes[] =
+ {
+ 1021, 4051, 8599, 16699, 65537
+ };
+ unsigned int index;
+
+ /* Work out the best prime number near the hash_size.
+ FIXME: This could be a more sophisticated algorithm,
+ but is it really worth implementing it ? */
+ for (index = 0; index < ARRAY_SIZE (hash_size_primes) - 1; ++index)
+ if (gas_hash_table_size <= hash_size_primes[index])
+ break;
+
+ return hash_size_primes[index];
+}
+
/* Create a hash table. This return a control block. */
struct hash_control *
hash_new (void)
{
- unsigned int size;
+ unsigned long size;
+ unsigned long alloc;
struct hash_control *ret;
- unsigned int alloc;
- size = DEFAULT_SIZE;
+ size = get_gas_hash_table_size ();
- ret = (struct hash_control *) xmalloc (sizeof *ret);
+ ret = xmalloc (sizeof *ret);
obstack_begin (&ret->memory, chunksize);
alloc = size * sizeof (struct hash_entry *);
- ret->table = (struct hash_entry **) obstack_alloc (&ret->memory, alloc);
+ ret->table = obstack_alloc (&ret->memory, alloc);
memset (ret->table, 0, alloc);
ret->size = size;
Each time we look up a string, we move it to the start of the list
for its hash code, to take advantage of referential locality. */
-static struct hash_entry *hash_lookup (struct hash_control *,
- const char *,
- struct hash_entry ***,
- unsigned long *);
-
static struct hash_entry *
-hash_lookup (struct hash_control *table, const char *key,
+hash_lookup (struct hash_control *table, const char *key, size_t len,
struct hash_entry ***plist, unsigned long *phash)
{
- register unsigned long hash;
- unsigned int len;
- register const unsigned char *s;
- register unsigned int c;
+ unsigned long hash;
+ size_t n;
+ unsigned int c;
unsigned int index;
struct hash_entry **list;
struct hash_entry *p;
#endif
hash = 0;
- len = 0;
- s = (const unsigned char *) key;
- while ((c = *s++) != '\0')
+ for (n = 0; n < len; n++)
{
+ c = key[n];
hash += c + (c << 17);
hash ^= hash >> 2;
- ++len;
}
hash += len + (len << 17);
hash ^= hash >> 2;
++table->string_compares;
#endif
- if (strcmp (p->string, key) == 0)
+ if (strncmp (p->string, key, len) == 0 && p->string[len] == '\0')
{
if (prev != NULL)
{
hash table. */
const char *
-hash_insert (struct hash_control *table, const char *key, PTR value)
+hash_insert (struct hash_control *table, const char *key, void *value)
{
struct hash_entry *p;
struct hash_entry **list;
unsigned long hash;
- p = hash_lookup (table, key, &list, &hash);
+ p = hash_lookup (table, key, strlen (key), &list, &hash);
if (p != NULL)
return "exists";
++table->insertions;
#endif
- p = (struct hash_entry *) obstack_alloc (&table->memory, sizeof (*p));
+ p = obstack_alloc (&table->memory, sizeof (*p));
p->string = key;
p->hash = hash;
p->data = value;
error. If an entry already exists, its value is replaced. */
const char *
-hash_jam (struct hash_control *table, const char *key, PTR value)
+hash_jam (struct hash_control *table, const char *key, void *value)
{
struct hash_entry *p;
struct hash_entry **list;
unsigned long hash;
- p = hash_lookup (table, key, &list, &hash);
+ p = hash_lookup (table, key, strlen (key), &list, &hash);
if (p != NULL)
{
#ifdef HASH_STATISTICS
++table->insertions;
#endif
- p = (struct hash_entry *) obstack_alloc (&table->memory, sizeof (*p));
+ p = obstack_alloc (&table->memory, sizeof (*p));
p->string = key;
p->hash = hash;
p->data = value;
value stored for the entry. If the entry is not found in the hash
table, this does nothing and returns NULL. */
-PTR
-hash_replace (struct hash_control *table, const char *key, PTR value)
+void *
+hash_replace (struct hash_control *table, const char *key, void *value)
{
struct hash_entry *p;
- PTR ret;
+ void *ret;
- p = hash_lookup (table, key, NULL, NULL);
+ p = hash_lookup (table, key, strlen (key), NULL, NULL);
if (p == NULL)
return NULL;
/* Find an entry in a hash table, returning its value. Returns NULL
if the entry is not found. */
-PTR
+void *
hash_find (struct hash_control *table, const char *key)
{
struct hash_entry *p;
- p = hash_lookup (table, key, NULL, NULL);
+ p = hash_lookup (table, key, strlen (key), NULL, NULL);
+ if (p == NULL)
+ return NULL;
+
+ return p->data;
+}
+
+/* As hash_find, but KEY is of length LEN and is not guaranteed to be
+ NUL-terminated. */
+
+void *
+hash_find_n (struct hash_control *table, const char *key, size_t len)
+{
+ struct hash_entry *p;
+
+ p = hash_lookup (table, key, len, NULL, NULL);
if (p == NULL)
return NULL;
/* Delete an entry from a hash table. This returns the value stored
for that entry, or NULL if there is no such entry. */
-PTR
-hash_delete (struct hash_control *table, const char *key)
+void *
+hash_delete (struct hash_control *table, const char *key, int freeme)
{
struct hash_entry *p;
struct hash_entry **list;
- p = hash_lookup (table, key, &list, NULL);
+ p = hash_lookup (table, key, strlen (key), &list, NULL);
if (p == NULL)
return NULL;
*list = p->next;
- /* Note that we never reclaim the memory for this entry. If gas
- ever starts deleting hash table entries in a big way, this will
- have to change. */
+ if (freeme)
+ obstack_free (&table->memory, p);
return p->data;
}
void
hash_traverse (struct hash_control *table,
- void (*pfn) (const char *key, PTR value))
+ void (*pfn) (const char *key, void *value))
{
unsigned int i;
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