1 /* Garbage collection for the GNU compiler.
2
3 Copyright (C) 1998-2023 Free Software Foundation, Inc.
4
5 This file is part of GCC.
6
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
11
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
20
21 #ifndef GCC_GGC_H
22 #define GCC_GGC_H
23
24 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
25 an external gc library that might be linked in. */
26
27 /* Internal functions and data structures used by the GTY
28 machinery, including the generated gt*.[hc] files. */
29
30 #include "gtype-desc.h"
31
32 /* One of these applies its third parameter (with cookie in the fourth
33 parameter) to each pointer in the object pointed to by the first
34 parameter, using the second parameter. */
35 typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
36 void *);
37
38 /* One of these is called before objects are re-ordered in memory.
39 The first parameter is the original object, the second is the
40 subobject that has had its pointers reordered, the third parameter
41 can compute the new values of a pointer when given the cookie in
42 the fourth parameter. */
43 typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
44 void *);
45
46 /* Used by the gt_pch_n_* routines. Register an object in the hash table. */
47 extern int gt_pch_note_object (void *, void *, gt_note_pointers,
48 size_t length_override = (size_t)-1);
49
50 /* Used by the gt_pch_p_* routines. Register address of a callback
51 pointer. */
52 extern void gt_pch_note_callback (void *, void *);
53
54 /* Used by the gt_pch_n_* routines. Register that an object has a reorder
55 function. */
56 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
57
58 /* generated function to clear caches in gc memory. */
59 extern void gt_clear_caches ();
60
61 /* Mark the object in the first parameter and anything it points to. */
62 typedef void (*gt_pointer_walker) (void *);
63
64 /* Structures for the easy way to mark roots.
65 In an array, terminated by having base == NULL. */
66 struct ggc_root_tab {
67 void *base;
68 size_t nelt;
69 size_t stride;
70 gt_pointer_walker cb;
71 gt_pointer_walker pchw;
72 };
73 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
74 /* Pointers to arrays of ggc_root_tab, terminated by NULL. */
75 extern const struct ggc_root_tab * const gt_ggc_rtab[];
76 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
77 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
78
79 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
80 to true. Otherwise evaluate to false. */
81 #define ggc_test_and_set_mark(EXPR) \
82 ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
83
84 #define ggc_mark(EXPR) \
85 do { \
86 const void *const a__ = (EXPR); \
87 if (a__ != NULL && a__ != (void *) 1) \
88 ggc_set_mark (a__); \
89 } while (0)
90
91 /* Actually set the mark on a particular region of memory, but don't
92 follow pointers. This function is called by ggc_mark_*. It
93 returns zero if the object was not previously marked; nonzero if
94 the object was already marked, or if, for any other reason,
95 pointers in this data structure should not be traversed. */
96 extern int ggc_set_mark (const void *);
97
98 /* Return 1 if P has been marked, zero otherwise.
99 P must have been allocated by the GC allocator; it mustn't point to
100 static objects, stack variables, or memory allocated with malloc. */
101 extern int ggc_marked_p (const void *);
102
103 /* PCH and GGC handling for strings, mostly trivial. */
104 extern void gt_pch_n_S (const void *);
105 extern void gt_pch_n_S2 (const void *, size_t);
106 extern void gt_ggc_m_S (const void *);
107
108 /* End of GTY machinery API. */
109
110 /* Initialize the string pool. */
111 extern void init_stringpool (void);
112
113 /* Initialize the garbage collector. */
114 extern void init_ggc (void);
115
116 /* When true, identifier nodes are considered as GC roots. When
117 false, identifier nodes are treated like any other GC-allocated
118 object, and the identifier hash table is treated as a weak
119 hash. */
120 extern bool ggc_protect_identifiers;
121
122 /* Write out all GCed objects to F. */
123 extern void gt_pch_save (FILE *f);
124
125
126 /* Allocation. */
127
128 /* The internal primitive. */
129 extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
130 size_t CXX_MEM_STAT_INFO)
131 ATTRIBUTE_MALLOC;
132
133 inline void *
134 ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
135 {
136 return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
137 }
138
139 extern size_t ggc_round_alloc_size (size_t requested_size);
140
141 /* Allocates cleared memory. */
142 extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
143 size_t, size_t
144 CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
145
146 inline void *
147 ggc_internal_cleared_alloc (size_t s CXX_MEM_STAT_INFO)
148 {
149 return ggc_internal_cleared_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
150 }
151
152 /* Resize a block. */
153 extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
154
155 /* Free a block. To be used when known for certain it's not reachable. */
156 extern void ggc_free (void *);
157
158 extern void dump_ggc_loc_statistics ();
159
160 /* Reallocator. */
161 #define GGC_RESIZEVEC(T, P, N) \
162 ((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
163
164 template<typename T>
165 void
166 finalize (void *p)
167 {
168 static_cast<T *> (p)->~T ();
169 }
170
171 template<typename T>
172 inline bool
173 need_finalization_p ()
174 {
175 #if GCC_VERSION >= 4003
176 return !__has_trivial_destructor (T);
177 #else
178 return true;
179 #endif
180 }
181
182 template<typename T>
183 inline T *
184 ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
185 {
186 if (need_finalization_p<T> ())
187 return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
188 PASS_MEM_STAT));
189 else
190 return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
191 PASS_MEM_STAT));
192 }
193
194 /* GGC allocation function that does not call finalizer for type
195 that have need_finalization_p equal to true. User is responsible
196 for calling of the destructor. */
197
198 template<typename T>
199 inline T *
200 ggc_alloc_no_dtor (ALONE_CXX_MEM_STAT_INFO)
201 {
202 return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
203 PASS_MEM_STAT));
204 }
205
206 template<typename T>
207 inline T *
208 ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
209 {
210 if (need_finalization_p<T> ())
211 return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
212 finalize<T>, 0, 1
213 PASS_MEM_STAT));
214 else
215 return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
216 PASS_MEM_STAT));
217 }
218
219 template<typename T>
220 inline T *
221 ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
222 {
223 if (need_finalization_p<T> ())
224 return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
225 sizeof (T), c PASS_MEM_STAT));
226 else
227 return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), NULL, 0, 0
228 PASS_MEM_STAT));
229 }
230
231 template<typename T>
232 inline T *
233 ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
234 {
235 if (need_finalization_p<T> ())
236 return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
237 finalize<T>,
238 sizeof (T), c
239 PASS_MEM_STAT));
240 else
241 return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
242 0, 0 PASS_MEM_STAT));
243 }
244
245 inline void *
246 ggc_alloc_atomic (size_t s CXX_MEM_STAT_INFO)
247 {
248 return ggc_internal_alloc (s PASS_MEM_STAT);
249 }
250
251 /* Call destructor and free the garbage collected memory. */
252
253 template <typename T>
254 inline void
255 ggc_delete (T *ptr)
256 {
257 ptr->~T ();
258 ggc_free (ptr);
259 }
260
261 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
262 If LENGTH is -1, then CONTENTS is assumed to be a
263 null-terminated string and the memory sized accordingly. */
264 extern const char *ggc_alloc_string (const char *contents, int length
265 CXX_MEM_STAT_INFO);
266
267 /* Make a copy of S, in GC-able memory. */
268 #define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
269
270 /* Invoke the collector. Garbage collection occurs only when this
271 function is called, not during allocations. */
272 enum ggc_collect {
273 GGC_COLLECT_HEURISTIC,
274 GGC_COLLECT_FORCE
275 };
276 extern void ggc_collect (enum ggc_collect mode = GGC_COLLECT_HEURISTIC);
277
278 /* Return unused memory pages to the system. */
279 extern void ggc_trim (void);
280
281 /* Assume that all GGC memory is reachable and grow the limits for next collection. */
282 extern void ggc_grow (void);
283
284 /* Register an additional root table. This can be useful for some
285 plugins. Does nothing if the passed pointer is NULL. */
286 extern void ggc_register_root_tab (const struct ggc_root_tab *);
287
288 /* Read objects previously saved with gt_pch_save from F. */
289 extern void gt_pch_restore (FILE *f);
290
291 /* Statistics. */
292
293 /* Print allocation statistics. */
294 extern void ggc_print_statistics (void);
295
296 extern void stringpool_statistics (void);
297
298 /* Heuristics. */
299 extern void init_ggc_heuristics (void);
300
301 /* Report current heap memory use to stderr. */
302 extern void report_heap_memory_use (void);
303
304 #define ggc_alloc_rtvec_sized(NELT) \
305 (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def) \
306 + ((NELT) - 1) * sizeof (rtx)) \
307
308 /* Memory statistics passing versions of some allocators. Too few of them to
309 make gengtype produce them, so just define the needed ones here. */
310 inline struct rtx_def *
311 ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
312 {
313 return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
314 }
315
316 inline union tree_node *
317 ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
318 {
319 return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
320 }
321
322 inline union tree_node *
323 ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
324 {
325 return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
326 }
327
328 inline gimple *
329 ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
330 {
331 return (gimple *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
332 }
333
334 inline void
335 gt_ggc_mx (const char *s)
336 {
337 ggc_test_and_set_mark (const_cast<char *> (s));
338 }
339
340 inline void
341 gt_pch_nx (const char *)
342 {
343 }
344
345 inline void gt_pch_nx (bool) { }
346 inline void gt_pch_nx (char) { }
347 inline void gt_pch_nx (signed char) { }
348 inline void gt_pch_nx (unsigned char) { }
349 inline void gt_pch_nx (short) { }
350 inline void gt_pch_nx (unsigned short) { }
351 inline void gt_pch_nx (int) { }
352 inline void gt_pch_nx (unsigned int) { }
353 inline void gt_pch_nx (long int) { }
354 inline void gt_pch_nx (unsigned long int) { }
355 inline void gt_pch_nx (long long int) { }
356 inline void gt_pch_nx (unsigned long long int) { }
357
358 inline void gt_ggc_mx (bool) { }
359 inline void gt_ggc_mx (char) { }
360 inline void gt_ggc_mx (signed char) { }
361 inline void gt_ggc_mx (unsigned char) { }
362 inline void gt_ggc_mx (short) { }
363 inline void gt_ggc_mx (unsigned short) { }
364 inline void gt_ggc_mx (int) { }
365 inline void gt_ggc_mx (unsigned int) { }
366 inline void gt_ggc_mx (long int) { }
367 inline void gt_ggc_mx (unsigned long int) { }
368 inline void gt_ggc_mx (long long int) { }
369 inline void gt_ggc_mx (unsigned long long int) { }
370
371 #endif