1 /* String pool for GCC.
2 Copyright (C) 2000, 2001 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 GNU CC is distributed in the hope that it will be useful, but WITHOUT
12 ANY 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 GNU CC; 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
);