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Diffstat (limited to 'gdb/bcache.c')
| -rw-r--r-- | gdb/bcache.c | 292 |
1 files changed, 0 insertions, 292 deletions
diff --git a/gdb/bcache.c b/gdb/bcache.c deleted file mode 100644 index 0f9c2a25ccc..00000000000 --- a/gdb/bcache.c +++ /dev/null @@ -1,292 +0,0 @@ -/* Implement a cached obstack. - Written by Fred Fish <fnf@cygnus.com> - Rewritten by Jim Blandy <jimb@cygnus.com> - Copyright 1999, 2000 Free Software Foundation, Inc. - - This file is part of GDB. - - This program 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 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include <stddef.h> -#include <stdlib.h> - -#include "defs.h" -#include "obstack.h" -#include "bcache.h" -#include "gdb_string.h" /* For memcpy declaration */ - -/* The old hash function was stolen from SDBM. This is what DB 3.0 uses now, - * and is better than the old one. - */ - -unsigned long -hash(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); -} - -/* Growing the bcache's hash table. */ - -/* If the average chain length grows beyond this, then we want to - resize our hash table. */ -#define CHAIN_LENGTH_THRESHOLD (5) - -static void -expand_hash_table (struct bcache *bcache) -{ - /* A table of good hash table sizes. Whenever we grow, we pick the - next larger size from this table. sizes[i] is close to 1 << (i+10), - so we roughly double the table size each time. After we fall off - the end of this table, we just double. Don't laugh --- there have - been executables sighted with a gigabyte of debug info. */ - static unsigned long sizes[] = { - 1021, 2053, 4099, 8191, 16381, 32771, - 65537, 131071, 262144, 524287, 1048573, 2097143, - 4194301, 8388617, 16777213, 33554467, 67108859, 134217757, - 268435459, 536870923, 1073741827, 2147483659UL - }; - unsigned int new_num_buckets; - struct bstring **new_buckets; - unsigned int i; - - /* Find the next size. */ - new_num_buckets = bcache->num_buckets * 2; - for (i = 0; i < (sizeof (sizes) / sizeof (sizes[0])); i++) - if (sizes[i] > bcache->num_buckets) - { - new_num_buckets = sizes[i]; - break; - } - - /* 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); - - bcache->structure_size -= (bcache->num_buckets - * sizeof (bcache->bucket[0])); - bcache->structure_size += new_size; - } - - /* Rehash all existing strings. */ - for (i = 0; i < bcache->num_buckets; i++) - { - struct bstring *s, *next; - - for (s = bcache->bucket[i]; s; s = next) - { - struct bstring **new_bucket; - next = s->next; - - new_bucket = &new_buckets[(hash (&s->d.data, s->length) - % new_num_buckets)]; - s->next = *new_bucket; - *new_bucket = s; - } - } - - /* Plug in the new table. */ - if (bcache->bucket) - xfree (bcache->bucket); - bcache->bucket = new_buckets; - bcache->num_buckets = new_num_buckets; -} - - -/* Looking up things in the bcache. */ - -/* The number of bytes needed to allocate a struct bstring whose data - is N bytes long. */ -#define BSTRING_SIZE(n) (offsetof (struct bstring, d.data) + (n)) - -/* Find a copy of the LENGTH bytes at ADDR in BCACHE. If BCACHE has - 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. */ -void * -bcache (void *addr, int length, struct bcache *bcache) -{ - int hash_index; - struct bstring *s; - - /* 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; - - hash_index = hash (addr, length) % bcache->num_buckets; - - /* Search the hash bucket for a string identical to the caller's. */ - for (s = bcache->bucket[hash_index]; s; s = s->next) - if (s->length == length - && ! memcmp (&s->d.data, addr, length)) - return &s->d.data; - - /* 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]; - bcache->bucket[hash_index] = new; - - bcache->unique_count++; - bcache->unique_size += length; - bcache->structure_size += BSTRING_SIZE (length); - - return &new->d.data; - } -} - - -/* Freeing bcaches. */ - -/* Free all the storage associated with BCACHE. */ -void -free_bcache (struct bcache *bcache) -{ - obstack_free (&bcache->cache, 0); - if (bcache->bucket) - xfree (bcache->bucket); - - /* This isn't necessary, but at least the bcache is always in a - consistent state. */ - memset (bcache, 0, sizeof (*bcache)); -} - - - -/* 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) - printf_filtered ("(not applicable)\n"); - else - printf_filtered ("%3d%%\n", portion * 100 / total); -} - - -/* Print statistics on BCACHE's memory usage and efficacity at - eliminating duplication. NAME should describe the kind of data - BCACHE holds. Statistics are printed using `printf_filtered' and - its ilk. */ -void -print_bcache_statistics (struct bcache *c, char *type) -{ - int occupied_buckets; - int max_chain_length; - int median_chain_length; - - /* Count the number of occupied buckets, and measure chain lengths. */ - { - unsigned int b; - int *chain_length - = (int *) alloca (c->num_buckets * sizeof (*chain_length)); - - occupied_buckets = 0; - - for (b = 0; b < c->num_buckets; b++) - { - struct bstring *s = c->bucket[b]; - - chain_length[b] = 0; - - if (s) - { - occupied_buckets++; - - while (s) - { - chain_length[b]++; - s = s->next; - } - } - } - - /* To compute the median, we need the set of chain lengths sorted. */ - qsort (chain_length, c->num_buckets, sizeof (chain_length[0]), - compare_ints); - - if (c->num_buckets > 0) - { - max_chain_length = chain_length[c->num_buckets - 1]; - median_chain_length = chain_length[c->num_buckets / 2]; - } - else - { - max_chain_length = 0; - median_chain_length = 0; - } - } - - printf_filtered (" Cached '%s' statistics:\n", type); - printf_filtered (" Total object count: %ld\n", c->total_count); - printf_filtered (" Unique object count: %lu\n", c->unique_count); - printf_filtered (" Percentage of duplicates, by count: "); - print_percentage (c->total_count - c->unique_count, c->total_count); - printf_filtered ("\n"); - - printf_filtered (" Total object size: %ld\n", c->total_size); - printf_filtered (" Unique object size: %ld\n", c->unique_size); - printf_filtered (" Percentage of duplicates, by size: "); - print_percentage (c->total_size - c->unique_size, c->total_size); - printf_filtered ("\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); - printf_filtered (" Net memory savings: "); - 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 population: "); - print_percentage (occupied_buckets, c->num_buckets); - printf_filtered (" Median hash chain length: %3d\n", - median_chain_length); - printf_filtered (" Average hash chain length: "); - if (c->num_buckets > 0) - printf_filtered ("%3lu\n", c->unique_count / c->num_buckets); - else - printf_filtered ("(not applicable)\n"); - printf_filtered (" Maximum hash chain length: %3d\n", max_chain_length); - printf_filtered ("\n"); -} |