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authorDJ Delorie <dj@redhat.com>2004-04-22 18:39:03 +0000
committerDJ Delorie <dj@redhat.com>2004-04-22 18:39:03 +0000
commitbb6a587dd383a443ab1b78669870f33cfbc117a2 (patch)
tree035e4dc50ffb72fa044558d6791ac2e5bc836e5b /libiberty/hashtab.c
parentfcf29e5f0e126c69ecb6ddd54613cc3c56a4a1b2 (diff)
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merge from gcc
Diffstat (limited to 'libiberty/hashtab.c')
-rw-r--r--libiberty/hashtab.c233
1 files changed, 171 insertions, 62 deletions
diff --git a/libiberty/hashtab.c b/libiberty/hashtab.c
index 2639428..6e7a44b 100644
--- a/libiberty/hashtab.c
+++ b/libiberty/hashtab.c
@@ -1,5 +1,6 @@
/* An expandable hash tables datatype.
- Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004
+ Free Software Foundation, Inc.
Contributed by Vladimir Makarov (vmakarov@cygnus.com).
This file is part of the libiberty library.
@@ -40,20 +41,29 @@ Boston, MA 02111-1307, USA. */
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
-
#ifdef HAVE_STRING_H
#include <string.h>
#endif
-
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
+#ifdef HAVE_LIMITS_H
+#include <limits.h>
+#endif
+#ifdef HAVE_STDINT_H
+#include <stdint.h>
+#endif
#include <stdio.h>
#include "libiberty.h"
+#include "ansidecl.h"
#include "hashtab.h"
+#ifndef CHAR_BIT
+#define CHAR_BIT 8
+#endif
+
/* This macro defines reserved value for empty table entry. */
#define EMPTY_ENTRY ((PTR) 0)
@@ -63,7 +73,10 @@ Boston, MA 02111-1307, USA. */
#define DELETED_ENTRY ((PTR) 1)
-static unsigned long higher_prime_number PARAMS ((unsigned long));
+static unsigned int higher_prime_index PARAMS ((unsigned long));
+static hashval_t htab_mod_1 PARAMS ((hashval_t, hashval_t, hashval_t, int));
+static hashval_t htab_mod PARAMS ((hashval_t, htab_t));
+static hashval_t htab_mod_m2 PARAMS ((hashval_t, htab_t));
static hashval_t hash_pointer PARAMS ((const void *));
static int eq_pointer PARAMS ((const void *, const void *));
static int htab_expand PARAMS ((htab_t));
@@ -75,69 +88,117 @@ static PTR *find_empty_slot_for_expand PARAMS ((htab_t, hashval_t));
htab_hash htab_hash_pointer = hash_pointer;
htab_eq htab_eq_pointer = eq_pointer;
-/* The following function returns a nearest prime number which is
- greater than N, and near a power of two. */
+/* Table of primes and multiplicative inverses.
+
+ Note that these are not minimally reduced inverses. Unlike when generating
+ code to divide by a constant, we want to be able to use the same algorithm
+ all the time. All of these inverses (are implied to) have bit 32 set.
+
+ For the record, here's the function that computed the table; it's a
+ vastly simplified version of the function of the same name from gcc. */
+
+#if 0
+unsigned int
+ceil_log2 (unsigned int x)
+{
+ int i;
+ for (i = 31; i >= 0 ; --i)
+ if (x > (1u << i))
+ return i+1;
+ abort ();
+}
-static unsigned long
-higher_prime_number (n)
+unsigned int
+choose_multiplier (unsigned int d, unsigned int *mlp, unsigned char *shiftp)
+{
+ unsigned long long mhigh;
+ double nx;
+ int lgup, post_shift;
+ int pow, pow2;
+ int n = 32, precision = 32;
+
+ lgup = ceil_log2 (d);
+ pow = n + lgup;
+ pow2 = n + lgup - precision;
+
+ nx = ldexp (1.0, pow) + ldexp (1.0, pow2);
+ mhigh = nx / d;
+
+ *shiftp = lgup - 1;
+ *mlp = mhigh;
+ return mhigh >> 32;
+}
+#endif
+
+struct prime_ent
+{
+ hashval_t prime;
+ hashval_t inv;
+ hashval_t inv_m2; /* inverse of prime-2 */
+ hashval_t shift;
+};
+
+static struct prime_ent const prime_tab[] = {
+ { 7, 0x24924925, 0x9999999b, 2 },
+ { 13, 0x3b13b13c, 0x745d1747, 3 },
+ { 31, 0x08421085, 0x1a7b9612, 4 },
+ { 61, 0x0c9714fc, 0x15b1e5f8, 5 },
+ { 127, 0x02040811, 0x0624dd30, 6 },
+ { 251, 0x05197f7e, 0x073260a5, 7 },
+ { 509, 0x01824366, 0x02864fc8, 8 },
+ { 1021, 0x00c0906d, 0x014191f7, 9 },
+ { 2039, 0x0121456f, 0x0161e69e, 10 },
+ { 4093, 0x00300902, 0x00501908, 11 },
+ { 8191, 0x00080041, 0x00180241, 12 },
+ { 16381, 0x000c0091, 0x00140191, 13 },
+ { 32749, 0x002605a5, 0x002a06e6, 14 },
+ { 65521, 0x000f00e2, 0x00110122, 15 },
+ { 131071, 0x00008001, 0x00018003, 16 },
+ { 262139, 0x00014002, 0x0001c004, 17 },
+ { 524287, 0x00002001, 0x00006001, 18 },
+ { 1048573, 0x00003001, 0x00005001, 19 },
+ { 2097143, 0x00004801, 0x00005801, 20 },
+ { 4194301, 0x00000c01, 0x00001401, 21 },
+ { 8388593, 0x00001e01, 0x00002201, 22 },
+ { 16777213, 0x00000301, 0x00000501, 23 },
+ { 33554393, 0x00001381, 0x00001481, 24 },
+ { 67108859, 0x00000141, 0x000001c1, 25 },
+ { 134217689, 0x000004e1, 0x00000521, 26 },
+ { 268435399, 0x00000391, 0x000003b1, 27 },
+ { 536870909, 0x00000019, 0x00000029, 28 },
+ { 1073741789, 0x0000008d, 0x00000095, 29 },
+ { 2147483647, 0x00000003, 0x00000007, 30 },
+ /* Avoid "decimal constant so large it is unsigned" for 4294967291. */
+ { 0xfffffffb, 0x00000006, 0x00000008, 31 }
+};
+
+/* The following function returns an index into the above table of the
+ nearest prime number which is greater than N, and near a power of two. */
+
+static unsigned int
+higher_prime_index (n)
unsigned long n;
{
- /* These are primes that are near, but slightly smaller than, a
- power of two. */
- static const unsigned long primes[] = {
- (unsigned long) 7,
- (unsigned long) 13,
- (unsigned long) 31,
- (unsigned long) 61,
- (unsigned long) 127,
- (unsigned long) 251,
- (unsigned long) 509,
- (unsigned long) 1021,
- (unsigned long) 2039,
- (unsigned long) 4093,
- (unsigned long) 8191,
- (unsigned long) 16381,
- (unsigned long) 32749,
- (unsigned long) 65521,
- (unsigned long) 131071,
- (unsigned long) 262139,
- (unsigned long) 524287,
- (unsigned long) 1048573,
- (unsigned long) 2097143,
- (unsigned long) 4194301,
- (unsigned long) 8388593,
- (unsigned long) 16777213,
- (unsigned long) 33554393,
- (unsigned long) 67108859,
- (unsigned long) 134217689,
- (unsigned long) 268435399,
- (unsigned long) 536870909,
- (unsigned long) 1073741789,
- (unsigned long) 2147483647,
- /* 4294967291L */
- ((unsigned long) 2147483647) + ((unsigned long) 2147483644),
- };
-
- const unsigned long *low = &primes[0];
- const unsigned long *high = &primes[sizeof(primes) / sizeof(primes[0])];
+ unsigned int low = 0;
+ unsigned int high = sizeof(prime_tab) / sizeof(prime_tab[0]);
while (low != high)
{
- const unsigned long *mid = low + (high - low) / 2;
- if (n > *mid)
+ unsigned int mid = low + (high - low) / 2;
+ if (n > prime_tab[mid].prime)
low = mid + 1;
else
high = mid;
}
/* If we've run out of primes, abort. */
- if (n > *low)
+ if (n > prime_tab[low].prime)
{
fprintf (stderr, "Cannot find prime bigger than %lu\n", n);
abort ();
}
- return *low;
+ return low;
}
/* Returns a hash code for P. */
@@ -177,6 +238,36 @@ htab_elements (htab)
return htab->n_elements - htab->n_deleted;
}
+/* Return X % Y. */
+
+static inline hashval_t
+htab_mod_1 (x, y, inv, shift)
+ hashval_t x, y, inv;
+ int shift;
+{
+ /* The multiplicative inverses computed above are for 32-bit types, and
+ requires that we be able to compute a highpart multiply. */
+#ifdef UNSIGNED_64BIT_TYPE
+ __extension__ typedef UNSIGNED_64BIT_TYPE ull;
+ if (sizeof (hashval_t) * CHAR_BIT <= 32)
+ {
+ hashval_t t1, t2, t3, t4, q, r;
+
+ t1 = ((ull)x * inv) >> 32;
+ t2 = x - t1;
+ t3 = t2 >> 1;
+ t4 = t1 + t3;
+ q = t4 >> shift;
+ r = x - (q * y);
+
+ return r;
+ }
+#endif
+
+ /* Otherwise just use the native division routines. */
+ return x % y;
+}
+
/* Compute the primary hash for HASH given HTAB's current size. */
static inline hashval_t
@@ -184,7 +275,8 @@ htab_mod (hash, htab)
hashval_t hash;
htab_t htab;
{
- return hash % htab_size (htab);
+ const struct prime_ent *p = &prime_tab[htab->size_prime_index];
+ return htab_mod_1 (hash, p->prime, p->inv, p->shift);
}
/* Compute the secondary hash for HASH given HTAB's current size. */
@@ -194,7 +286,8 @@ htab_mod_m2 (hash, htab)
hashval_t hash;
htab_t htab;
{
- return 1 + hash % (htab_size (htab) - 2);
+ const struct prime_ent *p = &prime_tab[htab->size_prime_index];
+ return 1 + htab_mod_1 (hash, p->prime - 2, p->inv_m2, p->shift);
}
/* This function creates table with length slightly longer than given
@@ -212,8 +305,11 @@ htab_create_alloc (size, hash_f, eq_f, del_f, alloc_f, free_f)
htab_free free_f;
{
htab_t result;
+ unsigned int size_prime_index;
+
+ size_prime_index = higher_prime_index (size);
+ size = prime_tab[size_prime_index].prime;
- size = higher_prime_number (size);
result = (htab_t) (*alloc_f) (1, sizeof (struct htab));
if (result == NULL)
return NULL;
@@ -225,6 +321,7 @@ htab_create_alloc (size, hash_f, eq_f, del_f, alloc_f, free_f)
return NULL;
}
result->size = size;
+ result->size_prime_index = size_prime_index;
result->hash_f = hash_f;
result->eq_f = eq_f;
result->del_f = del_f;
@@ -248,8 +345,11 @@ htab_create_alloc_ex (size, hash_f, eq_f, del_f, alloc_arg, alloc_f,
htab_free_with_arg free_f;
{
htab_t result;
+ unsigned int size_prime_index;
+
+ size_prime_index = higher_prime_index (size);
+ size = prime_tab[size_prime_index].prime;
- size = higher_prime_number (size);
result = (htab_t) (*alloc_f) (alloc_arg, 1, sizeof (struct htab));
if (result == NULL)
return NULL;
@@ -261,6 +361,7 @@ htab_create_alloc_ex (size, hash_f, eq_f, del_f, alloc_arg, alloc_f,
return NULL;
}
result->size = size;
+ result->size_prime_index = size_prime_index;
result->hash_f = hash_f;
result->eq_f = eq_f;
result->del_f = del_f;
@@ -412,19 +513,27 @@ htab_expand (htab)
PTR *olimit;
PTR *p;
PTR *nentries;
- size_t nsize;
+ size_t nsize, osize, elts;
+ unsigned int oindex, nindex;
oentries = htab->entries;
- olimit = oentries + htab->size;
+ oindex = htab->size_prime_index;
+ osize = htab->size;
+ olimit = oentries + osize;
+ elts = htab_elements (htab);
/* Resize only when table after removal of unused elements is either
too full or too empty. */
- if ((htab->n_elements - htab->n_deleted) * 2 > htab->size
- || ((htab->n_elements - htab->n_deleted) * 8 < htab->size
- && htab->size > 32))
- nsize = higher_prime_number ((htab->n_elements - htab->n_deleted) * 2);
+ if (elts * 2 > osize || (elts * 8 < osize && osize > 32))
+ {
+ nindex = higher_prime_index (elts * 2);
+ nsize = prime_tab[nindex].prime;
+ }
else
- nsize = htab->size;
+ {
+ nindex = oindex;
+ nsize = osize;
+ }
if (htab->alloc_with_arg_f != NULL)
nentries = (PTR *) (*htab->alloc_with_arg_f) (htab->alloc_arg, nsize,
@@ -435,7 +544,7 @@ htab_expand (htab)
return 0;
htab->entries = nentries;
htab->size = nsize;
-
+ htab->size_prime_index = nindex;
htab->n_elements -= htab->n_deleted;
htab->n_deleted = 0;