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) 1999-2020 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>
+#include <algorithm>
+
+namespace gdb {
/* 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
d;
};
-
-/* The structure for a bcache itself. The bcache is initialized, in
- bcache_xmalloc(), by filling it with zeros and then setting the
- corresponding obstack's malloc() and free() methods. */
-
-struct bcache
-{
- /* All the bstrings are allocated here. */
- struct obstack cache;
-
- /* How many hash buckets we're using. */
- unsigned int num_buckets;
-
- /* Hash buckets. This table is allocated using malloc, so when we
- grow the table we can return the old table to the system. */
- struct bstring **bucket;
-
- /* Statistics. */
- unsigned long unique_count; /* number of unique strings */
- long total_count; /* total number of strings cached, including dups */
- long unique_size; /* size of unique strings, in bytes */
- long total_size; /* total number of bytes cached, including dups */
- long structure_size; /* total size of bcache, including infrastructure */
- /* Number of times that the hash table is expanded and hence
- re-built, and the corresponding number of times that a string is
- [re]hashed as part of entering it into the expanded table. The
- total number of hashes can be computed by adding TOTAL_COUNT to
- expand_hash_count. */
- unsigned long expand_count;
- unsigned long expand_hash_count;
- /* Number of times that the half-hash compare hit (compare the upper
- 16 bits of hash values) hit, but the corresponding combined
- length/data compare missed. */
- unsigned long half_hash_miss_count;
-};
-
-/* 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);
-}
\f
/* Growing the bcache's hash table. */
resize our hash table. */
#define CHAIN_LENGTH_THRESHOLD (5)
-static void
-expand_hash_table (struct bcache *bcache)
+void
+bcache::expand_hash_table ()
{
/* 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),
/* Count the stats. Every unique item needs to be re-hashed and
re-entered. */
- bcache->expand_count++;
- bcache->expand_hash_count += bcache->unique_count;
+ m_expand_count++;
+ m_expand_hash_count += m_unique_count;
/* Find the next size. */
- new_num_buckets = bcache->num_buckets * 2;
+ new_num_buckets = m_num_buckets * 2;
for (i = 0; i < (sizeof (sizes) / sizeof (sizes[0])); i++)
- if (sizes[i] > bcache->num_buckets)
+ if (sizes[i] > m_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;
+ m_structure_size -= m_num_buckets * sizeof (m_bucket[0]);
+ m_structure_size += new_size;
}
/* Rehash all existing strings. */
- for (i = 0; i < bcache->num_buckets; i++)
+ for (i = 0; i < m_num_buckets; i++)
{
struct bstring *s, *next;
- for (s = bcache->bucket[i]; s; s = next)
+ for (s = m_bucket[i]; s; s = next)
{
struct bstring **new_bucket;
next = s->next;
- new_bucket = &new_buckets[(hash (&s->d.data, s->length)
+ new_bucket = &new_buckets[(m_hash_function (&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;
+ xfree (m_bucket);
+ m_bucket = new_buckets;
+ m_num_buckets = new_num_buckets;
}
\f
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. */
-static void *
-bcache_data (const void *addr, int length, struct bcache *bcache)
-{
- return deprecated_bcache_added (addr, length, bcache, NULL);
-}
-
-
-void *
-deprecated_bcache (const void *addr, int length, struct bcache *bcache)
-{
- return bcache_data (addr, length, bcache);
-}
-
-const void *
-bcache (const void *addr, int length, struct bcache *bcache)
-{
- return bcache_data (addr, length, bcache);
-}
-
/* 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. If
optional ADDED is not NULL, return 1 in case of new entry or 0 if
returning an old entry. */
-void *
-deprecated_bcache_added (const void *addr, int length, struct bcache *bcache,
- int *added)
+const void *
+bcache::insert (const void *addr, int length, int *added)
{
unsigned long full_hash;
unsigned short half_hash;
if (added)
*added = 0;
+ /* Lazily initialize the obstack. This can save quite a bit of
+ memory in some cases. */
+ if (m_total_count == 0)
+ {
+ /* We could use obstack_specify_allocation here instead, but
+ gdb_obstack.h specifies the allocation/deallocation
+ functions. */
+ obstack_init (&m_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);
+ if (m_unique_count >= m_num_buckets * CHAIN_LENGTH_THRESHOLD)
+ expand_hash_table ();
+
+ m_total_count++;
+ m_total_size += length;
- bcache->total_count++;
- bcache->total_size += length;
+ full_hash = m_hash_function (addr, length);
- full_hash = hash (addr, length);
half_hash = (full_hash >> 16);
- hash_index = full_hash % bcache->num_buckets;
+ hash_index = full_hash % m_num_buckets;
- /* Search the hash bucket for a string identical to the caller's.
+ /* Search the hash m_bucket for a string identical to the caller's.
As a short-circuit first compare the upper part of each hash
values. */
- for (s = bcache->bucket[hash_index]; s; s = s->next)
+ for (s = m_bucket[hash_index]; s; s = s->next)
{
if (s->half_hash == half_hash)
{
if (s->length == length
- && ! memcmp (&s->d.data, addr, length))
+ && m_compare_function (&s->d.data, addr, length))
return &s->d.data;
else
- bcache->half_hash_miss_count++;
+ m_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;
-
- bcache->unique_count++;
- bcache->unique_size += length;
- bcache->structure_size += BSTRING_SIZE (length);
+ struct bstring *newobj
+ = (struct bstring *) obstack_alloc (&m_cache,
+ BSTRING_SIZE (length));
+
+ memcpy (&newobj->d.data, addr, length);
+ newobj->length = length;
+ newobj->next = m_bucket[hash_index];
+ newobj->half_hash = half_hash;
+ m_bucket[hash_index] = newobj;
+
+ m_unique_count++;
+ m_unique_size += length;
+ m_structure_size += BSTRING_SIZE (length);
if (added)
*added = 1;
- return &new->d.data;
+ return &newobj->d.data;
}
}
\f
-/* Allocating and freeing bcaches. */
-struct bcache *
-bcache_xmalloc (void)
+/* Compare the byte string at ADDR1 of lenght LENGHT to the
+ string at ADDR2. Return 1 if they are equal. */
+
+int
+bcache::compare (const void *addr1, const void *addr2, 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);
- return b;
+ return memcmp (addr1, addr2, length) == 0;
}
/* Free all the storage associated with BCACHE. */
-void
-bcache_xfree (struct bcache *bcache)
+bcache::~bcache ()
{
- if (bcache == NULL)
- return;
- obstack_free (&bcache->cache, 0);
- xfree (bcache->bucket);
- xfree (bcache);
+ /* Only free the obstack if we actually initialized it. */
+ if (m_total_count > 0)
+ obstack_free (&m_cache, 0);
+ xfree (m_bucket);
}
\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)
+bcache::print_statistics (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, m_num_buckets + 1);
+ int *entry_size = XCNEWVEC (int, m_unique_count + 1);
int stringi = 0;
occupied_buckets = 0;
- for (b = 0; b < c->num_buckets; b++)
+ for (b = 0; b < m_num_buckets; b++)
{
- struct bstring *s = c->bucket[b];
+ struct bstring *s = m_bucket[b];
chain_length[b] = 0;
while (s)
{
- gdb_assert (b < c->num_buckets);
+ gdb_assert (b < m_num_buckets);
chain_length[b]++;
- gdb_assert (stringi < c->unique_count);
+ gdb_assert (stringi < m_unique_count);
entry_size[stringi++] = s->length;
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);
- qsort (entry_size, c->unique_count, sizeof (entry_size[0]),
- compare_ints);
+ /* To compute the median, we need the set of chain lengths
+ sorted. */
+ std::sort (chain_length, chain_length + m_num_buckets);
+ std::sort (entry_size, entry_size + m_unique_count);
- if (c->num_buckets > 0)
+ if (m_num_buckets > 0)
{
- max_chain_length = chain_length[c->num_buckets - 1];
- median_chain_length = chain_length[c->num_buckets / 2];
+ max_chain_length = chain_length[m_num_buckets - 1];
+ median_chain_length = chain_length[m_num_buckets / 2];
}
else
{
max_chain_length = 0;
median_chain_length = 0;
}
- if (c->unique_count > 0)
+ if (m_unique_count > 0)
{
- max_entry_size = entry_size[c->unique_count - 1];
- median_entry_size = entry_size[c->unique_count / 2];
+ max_entry_size = entry_size[m_unique_count - 1];
+ median_entry_size = entry_size[m_unique_count / 2];
}
else
{
xfree (entry_size);
}
- 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 (_(" M_Cached '%s' statistics:\n"), type);
+ printf_filtered (_(" Total object count: %ld\n"), m_total_count);
+ printf_filtered (_(" Unique object count: %lu\n"), m_unique_count);
printf_filtered (_(" Percentage of duplicates, by count: "));
- print_percentage (c->total_count - c->unique_count, c->total_count);
+ print_percentage (m_total_count - m_unique_count, m_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 (_(" Total object size: %ld\n"), m_total_size);
+ printf_filtered (_(" Unique object size: %ld\n"), m_unique_size);
printf_filtered (_(" Percentage of duplicates, by size: "));
- print_percentage (c->total_size - c->unique_size, c->total_size);
+ print_percentage (m_total_size - m_unique_size, m_total_size);
printf_filtered ("\n");
printf_filtered (_(" Max entry size: %d\n"), max_entry_size);
printf_filtered (_(" Average entry size: "));
- if (c->unique_count > 0)
- printf_filtered ("%ld\n", c->unique_size / c->unique_count);
+ if (m_unique_count > 0)
+ printf_filtered ("%ld\n", m_unique_size / m_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"),
- c->structure_size);
+ printf_filtered (_(" \
+Total memory used by bcache, including overhead: %ld\n"),
+ m_structure_size);
printf_filtered (_(" Percentage memory overhead: "));
- print_percentage (c->structure_size - c->unique_size, c->unique_size);
+ print_percentage (m_structure_size - m_unique_size, m_unique_size);
printf_filtered (_(" Net memory savings: "));
- print_percentage (c->total_size - c->structure_size, c->total_size);
+ print_percentage (m_total_size - m_structure_size, m_total_size);
printf_filtered ("\n");
- printf_filtered (_(" Hash table size: %3d\n"), c->num_buckets);
+ printf_filtered (_(" Hash table size: %3d\n"),
+ m_num_buckets);
printf_filtered (_(" Hash table expands: %lu\n"),
- c->expand_count);
+ m_expand_count);
printf_filtered (_(" Hash table hashes: %lu\n"),
- c->total_count + c->expand_hash_count);
+ m_total_count + m_expand_hash_count);
printf_filtered (_(" Half hash misses: %lu\n"),
- c->half_hash_miss_count);
+ m_half_hash_miss_count);
printf_filtered (_(" Hash table population: "));
- print_percentage (occupied_buckets, c->num_buckets);
+ print_percentage (occupied_buckets, m_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);
+ if (m_num_buckets > 0)
+ printf_filtered ("%3lu\n", m_unique_count / m_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)
+bcache::memory_used ()
{
- return obstack_memory_used (&bcache->cache);
+ if (m_total_count == 0)
+ return 0;
+ return obstack_memory_used (&m_cache);
}
+
+} /* namespace gdb */
projects / deliverable / binutils-gdb.git / blobdiff