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/* String pool for GCC.
Copyright (C) 2000, 2001 Free Software Foundation, Inc.
This file is part of GCC.
GCC 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) any later
version.
GCC 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 GCC; see the file COPYING. If not, write to the Free
Software Foundation, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
/* String text, identifier text and identifier node allocator. Strings
allocated by ggc_alloc_string are stored in an obstack which is
never shrunk. Identifiers are uniquely stored in a hash table.
We have our own private hash table implementation. libiberty's
hashtab.c is not used because it requires 100% average space
overhead per string, which is unacceptable. Also, this algorithm
is faster. */
#include "config.h"
#include "system.h"
#include "ggc.h"
#include "tree.h"
#include "hashtable.h"
/* The "" allocated string. */
const char empty_string[] = "";
/* Character strings, each containing a single decimal digit.
Written this way to save space. */
const char digit_vector[] = {
'0', 0, '1', 0, '2', 0, '3', 0, '4', 0,
'5', 0, '6', 0, '7', 0, '8', 0, '9', 0
};
struct ht *ident_hash;
static struct obstack string_stack;
static hashnode alloc_node PARAMS ((hash_table *));
static int mark_ident PARAMS ((struct cpp_reader *, hashnode, const PTR));
static void mark_ident_hash PARAMS ((void *));
/* Initialize the string pool. */
void
init_stringpool ()
{
/* Create with 16K (2^14) entries. */
ident_hash = ht_create (14);
ident_hash->alloc_node = alloc_node;
gcc_obstack_init (&string_stack);
ggc_add_root (&ident_hash, 1, sizeof ident_hash, mark_ident_hash);
}
/* Allocate a hash node. */
static hashnode
alloc_node (table)
hash_table *table ATTRIBUTE_UNUSED;
{
return GCC_IDENT_TO_HT_IDENT (make_node (IDENTIFIER_NODE));
}
/* Allocate and return a string constant of length LENGTH, containing
CONTENTS. If LENGTH is -1, CONTENTS is assumed to be a
nul-terminated string, and the length is calculated using strlen.
If the same string constant has been allocated before, that copy is
returned this time too. */
const char *
ggc_alloc_string (contents, length)
const char *contents;
int length;
{
if (length == -1)
length = strlen (contents);
if (length == 0)
return empty_string;
if (length == 1 && ISDIGIT (contents[0]))
return digit_string (contents[0] - '0');
obstack_grow0 (&string_stack, contents, length);
return obstack_finish (&string_stack);
}
/* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
If an identifier with that name has previously been referred to,
the same node is returned this time. */
tree
get_identifier (text)
const char *text;
{
hashnode ht_node = ht_lookup (ident_hash,
(const unsigned char *) text,
strlen (text), HT_ALLOC);
/* ht_node can't be NULL here. */
return HT_IDENT_TO_GCC_IDENT (ht_node);
}
/* Identical to get_identifier, except that the length is assumed
known. */
tree
get_identifier_with_length (text, length)
const char *text;
unsigned int length;
{
hashnode ht_node = ht_lookup (ident_hash,
(const unsigned char *) text,
length, HT_ALLOC);
/* ht_node can't be NULL here. */
return HT_IDENT_TO_GCC_IDENT (ht_node);
}
/* If an identifier with the name TEXT (a null-terminated string) has
previously been referred to, return that node; otherwise return
NULL_TREE. */
tree
maybe_get_identifier (text)
const char *text;
{
hashnode ht_node;
ht_node = ht_lookup (ident_hash, (const unsigned char *) text,
strlen (text), HT_NO_INSERT);
if (ht_node)
return HT_IDENT_TO_GCC_IDENT (ht_node);
return NULL_TREE;
}
/* Report some basic statistics about the string pool. */
void
stringpool_statistics ()
{
ht_dump_statistics (ident_hash);
}
/* Mark an identifier for GC. */
static int
mark_ident (pfile, h, v)
struct cpp_reader *pfile ATTRIBUTE_UNUSED;
hashnode h;
const PTR v ATTRIBUTE_UNUSED;
{
ggc_mark_nonnull_tree (HT_IDENT_TO_GCC_IDENT (h));
return 1;
}
/* Mark all identifiers for GC. */
static void
mark_ident_hash (arg)
PTR arg ATTRIBUTE_UNUSED;
{
ht_forall (ident_hash, mark_ident, NULL);
}
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