1 | /* String pool for GCC. |
2 | Copyright (C) 2000-2023 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 *; |
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 | stringpool_ggc_alloc (size_t x) |
42 | { |
43 | return ggc_alloc_atomic (s: x); |
44 | } |
45 | |
46 | /* Initialize the string pool. */ |
47 | void |
48 | 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 | if (ident_hash) |
53 | ht_destroy (ident_hash); |
54 | if (ident_hash_extra) |
55 | ht_destroy (ident_hash_extra); |
56 | |
57 | /* Create with 16K (2^14) entries. */ |
58 | ident_hash = ht_create (order: 14); |
59 | ident_hash->alloc_node = alloc_node; |
60 | ident_hash->alloc_subobject = stringpool_ggc_alloc; |
61 | |
62 | /* Create with 64 (2^6) entries. */ |
63 | ident_hash_extra = ht_create (order: 6); |
64 | ident_hash_extra->alloc_node = [] (cpp_hash_table *) |
65 | { |
66 | return HT_NODE (ggc_cleared_alloc<cpp_hashnode_extra> ()); |
67 | }; |
68 | ident_hash_extra->alloc_subobject = stringpool_ggc_alloc; |
69 | } |
70 | |
71 | /* Allocate a hash node. */ |
72 | static hashnode |
73 | alloc_node (cpp_hash_table *table ATTRIBUTE_UNUSED) |
74 | { |
75 | 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 | ggc_alloc_string (const char *contents, int length MEM_STAT_DECL) |
84 | { |
85 | if (length == -1) |
86 | length = strlen (s: contents); |
87 | |
88 | if (!length) |
89 | return "" ; |
90 | |
91 | char *result = (char *) ggc_alloc_atomic (s: length + 1); |
92 | memcpy (dest: result, src: contents, n: length); |
93 | result[length] = '\0'; |
94 | |
95 | 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 | get_identifier (const char *text) |
106 | { |
107 | hashnode ht_node = ht_lookup (ident_hash, |
108 | (const unsigned char *) text, |
109 | strlen (s: text), HT_ALLOC); |
110 | |
111 | /* ht_node can't be NULL here. */ |
112 | 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 | get_identifier_with_length (const char *text, size_t length) |
120 | { |
121 | 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 | 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 | maybe_get_identifier (const char *text) |
135 | { |
136 | hashnode ht_node; |
137 | |
138 | ht_node = ht_lookup (ident_hash, (const unsigned char *) text, |
139 | strlen (s: text), HT_NO_INSERT); |
140 | if (ht_node) |
141 | 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 | stringpool_statistics (void) |
150 | { |
151 | ht_dump_statistics (ident_hash); |
152 | } |
153 | |
154 | /* Mark an identifier for GC. */ |
155 | |
156 | static int |
157 | mark_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h, |
158 | const void *v ATTRIBUTE_UNUSED) |
159 | { |
160 | gt_ggc_m_9tree_node (HT_IDENT_TO_GCC_IDENT (h)); |
161 | return 1; |
162 | } |
163 | |
164 | /* Return true if an identifier should be removed from the table. */ |
165 | |
166 | static int |
167 | maybe_delete_ident (struct cpp_reader *pfile ATTRIBUTE_UNUSED, hashnode h, |
168 | const void *v ATTRIBUTE_UNUSED) |
169 | { |
170 | 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 | ggc_mark_stringpool (void) |
179 | { |
180 | ht_forall (ident_hash, mark_ident, NULL); |
181 | 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 | } |
188 | |
189 | /* Purge the identifier hash of identifiers which are no longer |
190 | referenced. */ |
191 | |
192 | void |
193 | ggc_purge_stringpool (void) |
194 | { |
195 | ht_purge (ident_hash, maybe_delete_ident, NULL); |
196 | ht_purge (ident_hash_extra, |
197 | [] (cpp_reader *, hashnode h, const void *) -> int |
198 | { |
199 | return !ggc_marked_p (h); |
200 | }, nullptr); |
201 | } |
202 | |
203 | /* Pointer-walking routine for strings (not very interesting, since |
204 | strings don't contain pointers). */ |
205 | |
206 | void |
207 | 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 | gcc_unreachable (); |
212 | } |
213 | |
214 | /* PCH pointer-walking routine for strings. */ |
215 | |
216 | void |
217 | gt_pch_n_S (const void *x) |
218 | { |
219 | gt_pch_note_object (CONST_CAST (void *, x), CONST_CAST (void *, x), |
220 | >_pch_p_S); |
221 | } |
222 | |
223 | void |
224 | gt_pch_n_S2 (const void *x, size_t string_len) |
225 | { |
226 | gt_pch_note_object (CONST_CAST (void *, x), CONST_CAST (void *, x), |
227 | >_pch_p_S, length_override: string_len); |
228 | } |
229 | |
230 | |
231 | /* User-callable entry point for marking string X. */ |
232 | |
233 | void |
234 | gt_pch_nx (const char *& x) |
235 | { |
236 | gt_pch_n_S (x); |
237 | } |
238 | |
239 | void |
240 | gt_pch_nx (char *& x) |
241 | { |
242 | gt_pch_n_S (x); |
243 | } |
244 | |
245 | void |
246 | gt_pch_nx (unsigned char *& x) |
247 | { |
248 | gt_pch_n_S (x); |
249 | } |
250 | |
251 | void |
252 | gt_pch_nx (unsigned char& x ATTRIBUTE_UNUSED) |
253 | { |
254 | } |
255 | |
256 | void |
257 | gt_pch_nx (unsigned char *x, gt_pointer_operator op, void *cookie) |
258 | { |
259 | op (x, NULL, cookie); |
260 | } |
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 (()) |
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 | ; |
284 | unsigned int ; |
285 | unsigned int ; |
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 | gt_pch_save_stringpool (void) |
295 | { |
296 | spd = ggc_alloc<string_pool_data> (); |
297 | spd->nslots = ident_hash->nslots; |
298 | spd->nelements = ident_hash->nelements; |
299 | spd->entries = ggc_vec_alloc<ht_identifier_ptr> (c: spd->nslots); |
300 | memcpy (dest: spd->entries, src: ident_hash->entries, |
301 | n: spd->nslots * sizeof (spd->entries[0])); |
302 | |
303 | spd2 = ggc_alloc<string_pool_data_extra> (); |
304 | spd2->nslots = ident_hash_extra->nslots; |
305 | spd2->nelements = ident_hash_extra->nelements; |
306 | spd2->entries = ggc_vec_alloc<ht_identifier_ptr> (c: spd2->nslots); |
307 | memcpy (dest: spd2->entries, src: ident_hash_extra->entries, |
308 | n: spd2->nslots * sizeof (spd2->entries[0])); |
309 | } |
310 | |
311 | /* Return the stringpool to its state before gt_pch_save_stringpool |
312 | was called. */ |
313 | |
314 | void |
315 | gt_pch_fixup_stringpool (void) |
316 | { |
317 | } |
318 | |
319 | /* A PCH file has been restored, which loaded SPD; fill the real hash table |
320 | from SPD. */ |
321 | |
322 | void |
323 | gt_pch_restore_stringpool (void) |
324 | { |
325 | ht_load (ht: ident_hash, entries: spd->entries, nslots: spd->nslots, nelements: spd->nelements, own: false); |
326 | ht_load (ht: ident_hash_extra, entries: spd2->entries, nslots: spd2->nslots, nelements: spd2->nelements, |
327 | own: false); |
328 | spd = NULL; |
329 | spd2 = NULL; |
330 | } |
331 | |
332 | #include "gt-stringpool.h" |
333 | |