Written by Fred Fish <fnf@cygnus.com>
Rewritten by Jim Blandy <jimb@cygnus.com>
- Copyright (C) 1999, 2000, 2002, 2003, 2007, 2008
- Free Software Foundation, Inc.
+ Copyright (C) 1999-2018 Free Software Foundation, Inc.
This file is part of GDB.
#include "defs.h"
#include "gdb_obstack.h"
#include "bcache.h"
-#include "gdb_string.h" /* For memcpy declaration */
-#include "gdb_assert.h"
-
-#include <stddef.h>
-#include <stdlib.h>
/* The type used to hold a single bcache string. The user data is
stored in d.data. Since it can be any type, it needs to have the
16 bits of hash values) hit, but the corresponding combined
length/data compare missed. */
unsigned long half_hash_miss_count;
+
+ /* Hash function to be used for this bcache object. */
+ unsigned long (*hash_function)(const void *addr, int length);
+
+ /* Compare function to be used for this bcache object. */
+ int (*compare_function)(const void *, const void *, int length);
};
-/* The old hash function was stolen from SDBM. This is what DB 3.0 uses now,
- * and is better than the old one.
- */
+/* The old hash function was stolen from SDBM. This is what DB 3.0
+ uses now, and is better than the old one. */
\f
unsigned long
hash(const void *addr, int length)
{
- const unsigned char *k, *e;
- unsigned long h;
-
- k = (const unsigned char *)addr;
- e = k+length;
- for (h=0; k< e;++k)
- {
- h *=16777619;
- h ^= *k;
- }
- return (h);
+ return hash_continue (addr, length, 0);
+}
+
+/* Continue the calculation of the hash H at the given address. */
+
+unsigned long
+hash_continue (const void *addr, int length, unsigned long h)
+{
+ const unsigned char *k, *e;
+
+ k = (const unsigned char *)addr;
+ e = k+length;
+ for (; k< e;++k)
+ {
+ h *=16777619;
+ h ^= *k;
+ }
+ return (h);
}
\f
/* Growing the bcache's hash table. */
/* Allocate the new table. */
{
size_t new_size = new_num_buckets * sizeof (new_buckets[0]);
+
new_buckets = (struct bstring **) xmalloc (new_size);
memset (new_buckets, 0, new_size);
struct bstring **new_bucket;
next = s->next;
- new_bucket = &new_buckets[(hash (&s->d.data, s->length)
+ new_bucket = &new_buckets[(bcache->hash_function (&s->d.data,
+ s->length)
% new_num_buckets)];
s->next = *new_bucket;
*new_bucket = s;
never seen those bytes before, add a copy of them to BCACHE. In
either case, return a pointer to BCACHE's copy of that string. */
const void *
-bcache (const void *addr, int length, struct bcache *bcache)
+bcache (const void *addr, int length, struct bcache *cache)
{
- return bcache_full (addr, length, bcache, NULL);
+ return bcache_full (addr, length, cache, NULL);
}
/* Find a copy of the LENGTH bytes at ADDR in BCACHE. If BCACHE has
if (added)
*added = 0;
+ /* Lazily initialize the obstack. This can save quite a bit of
+ memory in some cases. */
+ if (bcache->total_count == 0)
+ {
+ /* We could use obstack_specify_allocation here instead, but
+ gdb_obstack.h specifies the allocation/deallocation
+ functions. */
+ obstack_init (&bcache->cache);
+ }
+
/* If our average chain length is too high, expand the hash table. */
if (bcache->unique_count >= bcache->num_buckets * CHAIN_LENGTH_THRESHOLD)
expand_hash_table (bcache);
bcache->total_count++;
bcache->total_size += length;
- full_hash = hash (addr, length);
+ full_hash = bcache->hash_function (addr, length);
+
half_hash = (full_hash >> 16);
hash_index = full_hash % bcache->num_buckets;
if (s->half_hash == half_hash)
{
if (s->length == length
- && ! memcmp (&s->d.data, addr, length))
+ && bcache->compare_function (&s->d.data, addr, length))
return &s->d.data;
else
bcache->half_hash_miss_count++;
/* The user's string isn't in the list. Insert it after *ps. */
{
- struct bstring *new
- = obstack_alloc (&bcache->cache, BSTRING_SIZE (length));
- memcpy (&new->d.data, addr, length);
- new->length = length;
- new->next = bcache->bucket[hash_index];
- new->half_hash = half_hash;
- bcache->bucket[hash_index] = new;
+ struct bstring *newobj
+ = (struct bstring *) obstack_alloc (&bcache->cache,
+ BSTRING_SIZE (length));
+
+ memcpy (&newobj->d.data, addr, length);
+ newobj->length = length;
+ newobj->next = bcache->bucket[hash_index];
+ newobj->half_hash = half_hash;
+ bcache->bucket[hash_index] = newobj;
bcache->unique_count++;
bcache->unique_size += length;
if (added)
*added = 1;
- return &new->d.data;
+ return &newobj->d.data;
}
}
\f
+
+/* Compare the byte string at ADDR1 of lenght LENGHT to the
+ string at ADDR2. Return 1 if they are equal. */
+
+static int
+bcache_compare (const void *addr1, const void *addr2, int length)
+{
+ return memcmp (addr1, addr2, length) == 0;
+}
+
/* Allocating and freeing bcaches. */
+/* Allocated a bcache. HASH_FUNCTION and COMPARE_FUNCTION can be used
+ to pass in custom hash, and compare functions to be used by this
+ bcache. If HASH_FUNCTION is NULL hash() is used and if
+ COMPARE_FUNCTION is NULL memcmp() is used. */
+
struct bcache *
-bcache_xmalloc (void)
+bcache_xmalloc (unsigned long (*hash_function)(const void *, int length),
+ int (*compare_function)(const void *,
+ const void *,
+ int length))
{
/* Allocate the bcache pre-zeroed. */
- struct bcache *b = XCALLOC (1, struct bcache);
- /* We could use obstack_specify_allocation here instead, but
- gdb_obstack.h specifies the allocation/deallocation
- functions. */
- obstack_init (&b->cache);
+ struct bcache *b = XCNEW (struct bcache);
+
+ if (hash_function)
+ b->hash_function = hash_function;
+ else
+ b->hash_function = hash;
+
+ if (compare_function)
+ b->compare_function = compare_function;
+ else
+ b->compare_function = bcache_compare;
return b;
}
{
if (bcache == NULL)
return;
- obstack_free (&bcache->cache, 0);
+ /* Only free the obstack if we actually initialized it. */
+ if (bcache->total_count > 0)
+ obstack_free (&bcache->cache, 0);
xfree (bcache->bucket);
xfree (bcache);
}
\f
/* Printing statistics. */
-static int
-compare_ints (const void *ap, const void *bp)
-{
- /* Because we know we're comparing two ints which are positive,
- there's no danger of overflow here. */
- return * (int *) ap - * (int *) bp;
-}
-
-
static void
print_percentage (int portion, int total)
{
if (total == 0)
- /* i18n: Like "Percentage of duplicates, by count: (not applicable)" */
+ /* i18n: Like "Percentage of duplicates, by count: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
else
printf_filtered ("%3d%%\n", (int) (portion * 100.0 / total));
BCACHE holds. Statistics are printed using `printf_filtered' and
its ilk. */
void
-print_bcache_statistics (struct bcache *c, char *type)
+print_bcache_statistics (struct bcache *c, const char *type)
{
int occupied_buckets;
int max_chain_length;
lengths, and measure chain lengths. */
{
unsigned int b;
- int *chain_length = XCALLOC (c->num_buckets + 1, int);
- int *entry_size = XCALLOC (c->unique_count + 1, int);
+ int *chain_length = XCNEWVEC (int, c->num_buckets + 1);
+ int *entry_size = XCNEWVEC (int, c->unique_count + 1);
int stringi = 0;
occupied_buckets = 0;
}
}
- /* To compute the median, we need the set of chain lengths sorted. */
+ /* To compute the median, we need the set of chain lengths
+ sorted. */
qsort (chain_length, c->num_buckets, sizeof (chain_length[0]),
- compare_ints);
+ compare_positive_ints);
qsort (entry_size, c->unique_count, sizeof (entry_size[0]),
- compare_ints);
+ compare_positive_ints);
if (c->num_buckets > 0)
{
if (c->unique_count > 0)
printf_filtered ("%ld\n", c->unique_size / c->unique_count);
else
- /* i18n: "Average entry size: (not applicable)" */
+ /* i18n: "Average entry size: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
printf_filtered (_(" Median entry size: %d\n"), median_entry_size);
printf_filtered ("\n");
- printf_filtered (_(" Total memory used by bcache, including overhead: %ld\n"),
+ printf_filtered (_(" \
+Total memory used by bcache, including overhead: %ld\n"),
c->structure_size);
printf_filtered (_(" Percentage memory overhead: "));
print_percentage (c->structure_size - c->unique_size, c->unique_size);
print_percentage (c->total_size - c->structure_size, c->total_size);
printf_filtered ("\n");
- printf_filtered (_(" Hash table size: %3d\n"), c->num_buckets);
+ printf_filtered (_(" Hash table size: %3d\n"),
+ c->num_buckets);
printf_filtered (_(" Hash table expands: %lu\n"),
c->expand_count);
printf_filtered (_(" Hash table hashes: %lu\n"),
if (c->num_buckets > 0)
printf_filtered ("%3lu\n", c->unique_count / c->num_buckets);
else
- /* i18n: "Average hash chain length: (not applicable)" */
+ /* i18n: "Average hash chain length: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
- printf_filtered (_(" Maximum hash chain length: %3d\n"), max_chain_length);
+ printf_filtered (_(" Maximum hash chain length: %3d\n"),
+ max_chain_length);
printf_filtered ("\n");
}
int
bcache_memory_used (struct bcache *bcache)
{
+ if (bcache->total_count == 0)
+ return 0;
return obstack_memory_used (&bcache->cache);
}
projects / deliverable / binutils-gdb.git / blobdiff