Daily bump.
[official-gcc.git] / gcc / stringpool.c
blobf4d0daebdd9ce42b0254fa87b368a213ec057ef5
1 /* String pool for GCC.
2 Copyright (C) 2000-2013 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 3, or (at your option) any later
9 version.
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
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* String text, identifier text and identifier node allocator.
21 Identifiers are uniquely stored in a hash table.
23 We use cpplib's hash table implementation. libiberty's
24 hashtab.c is not used because it requires 100% average space
25 overhead per string, which is unacceptable. Also, this algorithm
26 is faster. */
28 #include "config.h"
29 #include "system.h"
30 #include "coretypes.h"
31 #include "ggc.h"
32 #include "ggc-internal.h"
33 #include "tree.h"
34 #include "symtab.h"
35 #include "cpplib.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 static 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 #define digit_string(d) (digit_vector + ((d) * 2))
49 struct ht *ident_hash;
51 static hashnode alloc_node (cpp_hash_table *);
52 static int mark_ident (struct cpp_reader *, hashnode, const void *);
54 static void *
55 stringpool_ggc_alloc (size_t x)
57 return ggc_alloc_atomic (x);
60 /* Initialize the string pool. */
61 void
62 init_stringpool (void)
64 /* Create with 16K (2^14) entries. */
65 ident_hash = ht_create (14);
66 ident_hash->alloc_node = alloc_node;
67 ident_hash->alloc_subobject = stringpool_ggc_alloc;
70 /* Allocate a hash node. */
71 static hashnode
72 alloc_node (cpp_hash_table *table ATTRIBUTE_UNUSED)
74 return GCC_IDENT_TO_HT_IDENT (make_node (IDENTIFIER_NODE));
77 /* Allocate and return a string constant of length LENGTH, containing
78 CONTENTS. If LENGTH is -1, CONTENTS is assumed to be a
79 nul-terminated string, and the length is calculated using strlen. */
81 const char *
82 ggc_alloc_string_stat (const char *contents, int length MEM_STAT_DECL)
84 char *result;
86 if (length == -1)
87 length = strlen (contents);
89 if (length == 0)
90 return empty_string;
91 if (length == 1 && ISDIGIT (contents[0]))
92 return digit_string (contents[0] - '0');
94 result = (char *) ggc_alloc_atomic_stat (length + 1 PASS_MEM_STAT);
95 memcpy (result, contents, length);
96 result[length] = '\0';
97 return (const char *) result;
100 /* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
101 If an identifier with that name has previously been referred to,
102 the same node is returned this time. */
104 #undef get_identifier
106 tree
107 get_identifier (const char *text)
109 hashnode ht_node = ht_lookup (ident_hash,
110 (const unsigned char *) text,
111 strlen (text), HT_ALLOC);
113 /* ht_node can't be NULL here. */
114 return HT_IDENT_TO_GCC_IDENT (ht_node);
117 /* Identical to get_identifier, except that the length is assumed
118 known. */
120 tree
121 get_identifier_with_length (const char *text, size_t length)
123 hashnode ht_node = ht_lookup (ident_hash,
124 (const unsigned char *) text,
125 length, HT_ALLOC);
127 /* ht_node can't be NULL here. */
128 return HT_IDENT_TO_GCC_IDENT (ht_node);
131 /* If an identifier with the name TEXT (a null-terminated string) has
132 previously been referred to, return that node; otherwise return
133 NULL_TREE. */
135 tree
136 maybe_get_identifier (const char *text)
138 hashnode ht_node;
140 ht_node = ht_lookup (ident_hash, (const unsigned char *) text,
141 strlen (text), HT_NO_INSERT);
142 if (ht_node)
143 return HT_IDENT_TO_GCC_IDENT (ht_node);
145 return NULL_TREE;
148 /* Report some basic statistics about the string pool. */
150 void
151 stringpool_statistics (void)
153 ht_dump_statistics (ident_hash);
156 /* Mark an identifier for GC. */
158 static int
159 mark_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h,
160 const void *v ATTRIBUTE_UNUSED)
162 gt_ggc_m_9tree_node (HT_IDENT_TO_GCC_IDENT (h));
163 return 1;
166 /* Return true if an identifier should be removed from the table. */
168 static int
169 maybe_delete_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h,
170 const void *v ATTRIBUTE_UNUSED)
172 return !ggc_marked_p (HT_IDENT_TO_GCC_IDENT (h));
175 /* Mark the trees hanging off the identifier node for GGC. These are
176 handled specially (not using gengtype) because identifiers are only
177 roots during one part of compilation. */
179 void
180 ggc_mark_stringpool (void)
182 ht_forall (ident_hash, mark_ident, NULL);
185 /* Purge the identifier hash of identifiers which are no longer
186 referenced. */
188 void
189 ggc_purge_stringpool (void)
191 ht_purge (ident_hash, maybe_delete_ident, NULL);
194 /* Pointer-walking routine for strings (not very interesting, since
195 strings don't contain pointers). */
197 void
198 gt_pch_p_S (void *obj ATTRIBUTE_UNUSED, void *x ATTRIBUTE_UNUSED,
199 gt_pointer_operator op ATTRIBUTE_UNUSED,
200 void *cookie ATTRIBUTE_UNUSED)
204 /* PCH pointer-walking routine for strings. */
206 void
207 gt_pch_n_S (const void *x)
209 gt_pch_note_object (CONST_CAST (void *, x), CONST_CAST (void *, x),
210 &gt_pch_p_S);
214 /* User-callable entry point for marking string X. */
216 void
217 gt_pch_nx (const char *& x)
219 gt_pch_n_S (x);
222 void
223 gt_pch_nx (unsigned char *& x)
225 gt_pch_n_S (x);
228 void
229 gt_pch_nx (unsigned char& x ATTRIBUTE_UNUSED)
233 void
234 gt_pch_nx (unsigned char *x, gt_pointer_operator op, void *cookie)
236 op (x, cookie);
239 /* Handle saving and restoring the string pool for PCH. */
241 /* SPD is saved in the PCH file and holds the information needed
242 to restore the string pool. */
244 struct GTY(()) string_pool_data {
245 ht_identifier_ptr *
246 GTY((length ("%h.nslots"),
247 nested_ptr (union tree_node, "%h ? GCC_IDENT_TO_HT_IDENT (%h) : NULL",
248 "%h ? HT_IDENT_TO_GCC_IDENT (%h) : NULL")))
249 entries;
250 unsigned int nslots;
251 unsigned int nelements;
254 static GTY(()) struct string_pool_data * spd;
256 /* Save the stringpool data in SPD. */
258 void
259 gt_pch_save_stringpool (void)
261 spd = ggc_alloc_string_pool_data ();
262 spd->nslots = ident_hash->nslots;
263 spd->nelements = ident_hash->nelements;
264 spd->entries = ggc_alloc_vec_ht_identifier_ptr (spd->nslots);
265 memcpy (spd->entries, ident_hash->entries,
266 spd->nslots * sizeof (spd->entries[0]));
269 /* Return the stringpool to its state before gt_pch_save_stringpool
270 was called. */
272 void
273 gt_pch_fixup_stringpool (void)
277 /* A PCH file has been restored, which loaded SPD; fill the real hash table
278 from SPD. */
280 void
281 gt_pch_restore_stringpool (void)
283 ht_load (ident_hash, spd->entries, spd->nslots, spd->nelements, false);
284 spd = NULL;
287 #include "gt-stringpool.h"