1 /* String pool for GCC.
2 Copyright (C) 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 2, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
21 /* String text, identifer text and identifier node allocator. Strings
22 allocated by ggc_alloc_string are stored in an obstack which is
23 never shrunk. Identifiers are uniquely stored in a hash table.
25 We have our own private hash table implementation. libiberty's
26 hashtab.c is not used because it requires 100% average space
27 overhead per string, which is unacceptable. Also, this algorithm
34 #include "hashtable.h"
37 /* The "" allocated string. */
38 const char empty_string[] = "";
40 /* Character strings, each containing a single decimal digit.
41 Written this way to save space. */
42 const char digit_vector[] = {
43 '0', 0, '1', 0, '2', 0, '3', 0, '4', 0,
44 '5', 0, '6', 0, '7', 0, '8', 0, '9', 0
47 struct ht *ident_hash;
48 static struct obstack string_stack;
50 static hashnode alloc_node PARAMS ((hash_table *));
51 static int mark_ident PARAMS ((struct cpp_reader *, hashnode, const PTR));
52 static void mark_ident_hash PARAMS ((void *));
54 /* Initialize the string pool. */
58 /* Create with 16K (2^14) entries. */
59 ident_hash = ht_create (14);
60 ident_hash->alloc_node = alloc_node;
61 gcc_obstack_init (&string_stack);
62 ggc_add_root (&ident_hash, 1, sizeof ident_hash, mark_ident_hash);
65 /* Allocate a hash node. */
68 hash_table *table ATTRIBUTE_UNUSED;
70 return GCC_IDENT_TO_HT_IDENT (make_node (IDENTIFIER_NODE));
73 /* Allocate and return a string constant of length LENGTH, containing
74 CONTENTS. If LENGTH is -1, CONTENTS is assumed to be a
75 nul-terminated string, and the length is calculated using strlen.
76 If the same string constant has been allocated before, that copy is
77 returned this time too. */
80 ggc_alloc_string (contents, length)
85 length = strlen (contents);
89 if (length == 1 && contents[0] >= '0' && contents[0] <= '9')
90 return digit_string (contents[0] - '0');
92 obstack_grow0 (&string_stack, contents, length);
93 return obstack_finish (&string_stack);
96 /* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
97 If an identifier with that name has previously been referred to,
98 the same node is returned this time. */
101 get_identifier (text)
104 hashnode ht_node = ht_lookup (ident_hash,
105 (const unsigned char *) text,
106 strlen (text), HT_ALLOC);
108 /* ht_node can't be NULL here. */
109 return HT_IDENT_TO_GCC_IDENT (ht_node);
112 /* If an identifier with the name TEXT (a null-terminated string) has
113 previously been referred to, return that node; otherwise return
117 maybe_get_identifier (text)
122 ht_node = ht_lookup (ident_hash, (const unsigned char *) text,
123 strlen (text), HT_NO_INSERT);
125 return HT_IDENT_TO_GCC_IDENT (ht_node);
130 /* Record the size of an identifier node for the language in use.
131 SIZE is the total size in bytes.
132 This is called by the language-specific files. This must be
133 called before allocating any identifiers. */
136 set_identifier_size (size)
139 tree_code_length[(int) IDENTIFIER_NODE]
140 = (size - sizeof (struct tree_common)) / sizeof (tree);
143 /* Report some basic statistics about the string pool. */
146 stringpool_statistics ()
148 ht_dump_statistics (ident_hash);
151 /* Mark an identifier for GC. */
154 mark_ident (pfile, h, v)
155 struct cpp_reader *pfile ATTRIBUTE_UNUSED;
157 const PTR v ATTRIBUTE_UNUSED;
159 ggc_mark_nonnull_tree (HT_IDENT_TO_GCC_IDENT (h));
163 /* Mark all identifiers for GC. */
166 mark_ident_hash (arg)
167 PTR arg ATTRIBUTE_UNUSED;
169 ht_forall (ident_hash, mark_ident, NULL);