Line data Source code
1 : /* String pool for GCC.
2 : Copyright (C) 2000-2026 Free Software Foundation, Inc.
3 :
4 : This file is part of GCC.
5 :
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.
10 :
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.
15 :
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/>. */
19 :
20 : /* String text, identifier text and identifier node allocator.
21 : Identifiers are uniquely stored in a hash table.
22 :
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. */
27 :
28 : #include "config.h"
29 : #include "system.h"
30 : #include "coretypes.h"
31 : #include "tree.h"
32 : #include "cpplib.h"
33 :
34 : struct ht *ident_hash;
35 : struct ht *ident_hash_extra;
36 :
37 : static hashnode alloc_node (cpp_hash_table *);
38 : static int mark_ident (struct cpp_reader *, hashnode, const void *);
39 :
40 : static void *
41 1920536570 : stringpool_ggc_alloc (size_t x)
42 : {
43 1920536570 : return ggc_alloc_atomic (x);
44 : }
45 :
46 : /* Initialize the string pool. */
47 : void
48 285722 : init_stringpool (void)
49 : {
50 : /* Clean up if we're called more than once.
51 : (We can't make this idempotent since identifiers contain state) */
52 285722 : if (ident_hash)
53 1200 : ht_destroy (ident_hash);
54 285722 : if (ident_hash_extra)
55 1200 : ht_destroy (ident_hash_extra);
56 :
57 : /* Create with 16K (2^14) entries. */
58 285722 : ident_hash = ht_create (14);
59 285722 : ident_hash->alloc_node = alloc_node;
60 285722 : ident_hash->alloc_subobject = stringpool_ggc_alloc;
61 :
62 : /* Create with 64 (2^6) entries. */
63 285722 : ident_hash_extra = ht_create (6);
64 285722 : ident_hash_extra->alloc_node = [] (cpp_hash_table *)
65 : {
66 : return HT_NODE (ggc_cleared_alloc<cpp_hashnode_extra> ());
67 : };
68 285722 : ident_hash_extra->alloc_subobject = stringpool_ggc_alloc;
69 285722 : }
70 :
71 : /* Allocate a hash node. */
72 : static hashnode
73 1693858740 : alloc_node (cpp_hash_table *table ATTRIBUTE_UNUSED)
74 : {
75 1693858740 : return GCC_IDENT_TO_HT_IDENT (make_node (IDENTIFIER_NODE));
76 : }
77 :
78 : /* Allocate and return a string constant of length LENGTH, containing
79 : CONTENTS. If LENGTH is -1, CONTENTS is assumed to be a
80 : nul-terminated string, and the length is calculated using strlen. */
81 :
82 : const char *
83 513711821 : ggc_alloc_string (const char *contents, int length MEM_STAT_DECL)
84 : {
85 513711821 : if (length == -1)
86 513569604 : length = strlen (contents);
87 :
88 513711821 : if (!length)
89 : return "";
90 :
91 513511464 : char *result = (char *) ggc_alloc_atomic (length + 1);
92 513511464 : memcpy (result, contents, length);
93 513511464 : result[length] = '\0';
94 :
95 513511464 : return (const char *) result;
96 : }
97 :
98 : /* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
99 : If an identifier with that name has previously been referred to,
100 : the same node is returned this time. */
101 :
102 : #undef get_identifier
103 :
104 : tree
105 1662888430 : get_identifier (const char *text)
106 : {
107 1662888430 : hashnode ht_node = ht_lookup (ident_hash,
108 : (const unsigned char *) text,
109 : strlen (text), HT_ALLOC);
110 :
111 : /* ht_node can't be NULL here. */
112 1662888430 : return HT_IDENT_TO_GCC_IDENT (ht_node);
113 : }
114 :
115 : /* Identical to get_identifier, except that the length is assumed
116 : known. */
117 :
118 : tree
119 335004144 : get_identifier_with_length (const char *text, size_t length)
120 : {
121 335004144 : hashnode ht_node = ht_lookup (ident_hash,
122 : (const unsigned char *) text,
123 : length, HT_ALLOC);
124 :
125 : /* ht_node can't be NULL here. */
126 335004144 : return HT_IDENT_TO_GCC_IDENT (ht_node);
127 : }
128 :
129 : /* If an identifier with the name TEXT (a null-terminated string) has
130 : previously been referred to, return that node; otherwise return
131 : NULL_TREE. */
132 :
133 : tree
134 394152109 : maybe_get_identifier (const char *text)
135 : {
136 394152109 : hashnode ht_node;
137 :
138 394152109 : ht_node = ht_lookup (ident_hash, (const unsigned char *) text,
139 : strlen (text), HT_NO_INSERT);
140 394152109 : if (ht_node)
141 34782327 : return HT_IDENT_TO_GCC_IDENT (ht_node);
142 :
143 : return NULL_TREE;
144 : }
145 :
146 : /* Report some basic statistics about the string pool. */
147 :
148 : void
149 0 : stringpool_statistics (void)
150 : {
151 0 : ht_dump_statistics (ident_hash);
152 0 : }
153 :
154 : /* Mark an identifier for GC. */
155 :
156 : static int
157 2392688822 : mark_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h,
158 : const void *v ATTRIBUTE_UNUSED)
159 : {
160 2392688822 : gt_ggc_m_9tree_node (HT_IDENT_TO_GCC_IDENT (h));
161 2392688822 : return 1;
162 : }
163 :
164 : /* Return true if an identifier should be removed from the table. */
165 :
166 : static int
167 2430635047 : maybe_delete_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h,
168 : const void *v ATTRIBUTE_UNUSED)
169 : {
170 2430635047 : return !ggc_marked_p (HT_IDENT_TO_GCC_IDENT (h));
171 : }
172 :
173 : /* Mark the trees hanging off the identifier node for GGC. These are
174 : handled specially (not using gengtype) because identifiers are only
175 : roots during one part of compilation. */
176 :
177 : void
178 154392 : ggc_mark_stringpool (void)
179 : {
180 154392 : ht_forall (ident_hash, mark_ident, NULL);
181 154392 : ht_forall (ident_hash_extra,
182 : [] (cpp_reader *, hashnode h, const void *)
183 : {
184 : gt_ggc_m_18cpp_hashnode_extra (h);
185 : return 1;
186 : }, nullptr);
187 154392 : }
188 :
189 : /* Purge the identifier hash of identifiers which are no longer
190 : referenced. */
191 :
192 : void
193 564748 : ggc_purge_stringpool (void)
194 : {
195 564748 : ht_purge (ident_hash, maybe_delete_ident, NULL);
196 564748 : ht_purge (ident_hash_extra,
197 : [] (cpp_reader *, hashnode h, const void *) -> int
198 : {
199 : return !ggc_marked_p (h);
200 : }, nullptr);
201 564748 : }
202 :
203 : /* Pointer-walking routine for strings (not very interesting, since
204 : strings don't contain pointers). */
205 :
206 : void
207 0 : gt_pch_p_S (void *obj ATTRIBUTE_UNUSED, void *x ATTRIBUTE_UNUSED,
208 : gt_pointer_operator op ATTRIBUTE_UNUSED,
209 : void *cookie ATTRIBUTE_UNUSED)
210 : {
211 0 : gcc_unreachable ();
212 : }
213 :
214 : /* PCH pointer-walking routine for strings. */
215 :
216 : void
217 740237 : gt_pch_n_S (const void *x)
218 : {
219 740237 : gt_pch_note_object (const_cast<void *> (x), const_cast<void *> (x),
220 : >_pch_p_S);
221 740237 : }
222 :
223 : void
224 2058330 : gt_pch_n_S2 (const void *x, size_t string_len)
225 : {
226 2058330 : gt_pch_note_object (const_cast<void *> (x), const_cast<void *> (x),
227 : >_pch_p_S, string_len);
228 2058330 : }
229 :
230 :
231 : /* User-callable entry point for marking string X. */
232 :
233 : void
234 0 : gt_pch_nx (const char *& x)
235 : {
236 0 : gt_pch_n_S (x);
237 0 : }
238 :
239 : void
240 0 : gt_pch_nx (char *& x)
241 : {
242 0 : gt_pch_n_S (x);
243 0 : }
244 :
245 : void
246 0 : gt_pch_nx (unsigned char *& x)
247 : {
248 0 : gt_pch_n_S (x);
249 0 : }
250 :
251 : void
252 0 : gt_pch_nx (unsigned char& x ATTRIBUTE_UNUSED)
253 : {
254 0 : }
255 :
256 : void
257 0 : gt_pch_nx (unsigned char *x, gt_pointer_operator op, void *cookie)
258 : {
259 0 : op (x, NULL, cookie);
260 0 : }
261 :
262 : /* Handle saving and restoring the string pool for PCH. */
263 :
264 : /* SPD is saved in the PCH file and holds the information needed
265 : to restore the string pool. */
266 :
267 : struct GTY(()) string_pool_data {
268 : ht_identifier_ptr *
269 : GTY((length ("%h.nslots"),
270 : nested_ptr (union tree_node, "%h ? GCC_IDENT_TO_HT_IDENT (%h) : NULL",
271 : "%h ? HT_IDENT_TO_GCC_IDENT (%h) : NULL")))
272 : entries;
273 : unsigned int nslots;
274 : unsigned int nelements;
275 : };
276 :
277 : struct GTY (()) string_pool_data_extra
278 : {
279 : ht_identifier_ptr *
280 : GTY((length ("%h.nslots"),
281 : nested_ptr (cpp_hashnode_extra, "%h ? HT_NODE (%h) : nullptr",
282 : "(cpp_hashnode_extra *)%h")))
283 : entries;
284 : unsigned int nslots;
285 : unsigned int nelements;
286 : };
287 :
288 : static GTY(()) struct string_pool_data * spd;
289 : static GTY(()) struct string_pool_data_extra *spd2;
290 :
291 : /* Save the stringpool data in SPD. */
292 :
293 : void
294 428 : gt_pch_save_stringpool (void)
295 : {
296 428 : spd = ggc_alloc<string_pool_data> ();
297 428 : spd->nslots = ident_hash->nslots;
298 428 : spd->nelements = ident_hash->nelements;
299 428 : spd->entries = ggc_vec_alloc<ht_identifier_ptr> (spd->nslots);
300 428 : memcpy (spd->entries, ident_hash->entries,
301 428 : spd->nslots * sizeof (spd->entries[0]));
302 :
303 428 : spd2 = ggc_alloc<string_pool_data_extra> ();
304 428 : spd2->nslots = ident_hash_extra->nslots;
305 428 : spd2->nelements = ident_hash_extra->nelements;
306 428 : spd2->entries = ggc_vec_alloc<ht_identifier_ptr> (spd2->nslots);
307 428 : memcpy (spd2->entries, ident_hash_extra->entries,
308 428 : spd2->nslots * sizeof (spd2->entries[0]));
309 428 : }
310 :
311 : /* Return the stringpool to its state before gt_pch_save_stringpool
312 : was called. */
313 :
314 : void
315 428 : gt_pch_fixup_stringpool (void)
316 : {
317 428 : }
318 :
319 : /* A PCH file has been restored, which loaded SPD; fill the real hash table
320 : from SPD. */
321 :
322 : void
323 350 : gt_pch_restore_stringpool (void)
324 : {
325 350 : ht_load (ident_hash, spd->entries, spd->nslots, spd->nelements, false);
326 350 : ht_load (ident_hash_extra, spd2->entries, spd2->nslots, spd2->nelements,
327 : false);
328 350 : spd = NULL;
329 350 : spd2 = NULL;
330 350 : }
331 :
332 : #include "gt-stringpool.h"
|
