GCC Middle and Back End API Reference
ggc.h
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1/* Garbage collection for the GNU compiler.
2
3 Copyright (C) 1998-2024 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 3, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along 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. */
35typedef 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. */
43typedef 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. */
47extern 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. */
52extern 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. */
56extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
57
58/* generated function to clear caches in gc memory. */
59extern void gt_clear_caches ();
60
61/* Mark the object in the first parameter and anything it points to. */
62typedef void (*gt_pointer_walker) (void *);
63
64/* Structures for the easy way to mark roots.
65 In an array, terminated by having base == NULL. */
73#define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
74/* Pointers to arrays of ggc_root_tab, terminated by NULL. */
75extern const struct ggc_root_tab * const gt_ggc_rtab[];
76extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
77extern 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 false if the object was not previously marked; true if
94 the object was already marked, or if, for any other reason,
95 pointers in this data structure should not be traversed. */
96extern bool ggc_set_mark (const void *);
97
98/* Return true 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. */
101extern bool ggc_marked_p (const void *);
102
103/* PCH and GGC handling for strings, mostly trivial. */
104extern void gt_pch_n_S (const void *);
105extern void gt_pch_n_S2 (const void *, size_t);
106extern void gt_ggc_m_S (const void *);
107
108/* End of GTY machinery API. */
109
110/* Initialize the string pool. */
111extern void init_stringpool (void);
112
113/* Initialize the garbage collector. */
114extern 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. */
120extern bool ggc_protect_identifiers;
121
122/* Write out all GCed objects to F. */
123extern void gt_pch_save (FILE *f);
124
125
126/* Allocation. */
127
128/* The internal primitive. */
129extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
130 size_t CXX_MEM_STAT_INFO)
132
133inline void *
138
139extern size_t ggc_round_alloc_size (size_t requested_size);
140
141/* Allocates cleared memory. */
142extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
143 size_t, size_t
145
146inline void *
151
152/* Resize a block. */
153extern 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. */
156extern void ggc_free (void *);
157
158extern 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
164template<typename T>
165void
166finalize (void *p)
167{
168 static_cast<T *> (p)->~T ();
169}
170
171template<typename T>
172inline bool
174{
175#if GCC_VERSION >= 4003
176 return !__has_trivial_destructor (T);
177#else
178 return true;
179#endif
180}
181
182template<typename T>
183inline T *
185{
187 return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
189 else
190 return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
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
198template<typename T>
199inline T *
201{
202 return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
204}
205
206template<typename T>
207inline T *
209{
211 return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
212 finalize<T>, 0, 1
214 else
215 return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
217}
218
219template<typename T>
220inline T *
222{
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
229}
230
231template<typename T>
232inline T *
234{
236 return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
238 sizeof (T), c
240 else
241 return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
242 0, 0 PASS_MEM_STAT));
243}
244
245inline void *
250
251/* Call destructor and free the garbage collected memory. */
252
253template <typename T>
254inline void
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. */
264extern const char *ggc_alloc_string (const char *contents, int length
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. */
276extern void ggc_collect (enum ggc_collect mode = GGC_COLLECT_HEURISTIC);
277
278/* Return unused memory pages to the system. */
279extern void ggc_trim (void);
280
281/* Assume that all GGC memory is reachable and grow the limits for next collection. */
282extern 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. */
286extern void ggc_register_root_tab (const struct ggc_root_tab *);
287
288/* Read objects previously saved with gt_pch_save from F. */
289extern void gt_pch_restore (FILE *f);
290
291/* Statistics. */
292
293/* Print allocation statistics. */
294extern void ggc_print_statistics (void);
295
296extern void stringpool_statistics (void);
297
298/* Heuristics. */
299extern void init_ggc_heuristics (void);
300
301/* Report current heap memory use to stderr. */
302extern 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. */
310inline struct rtx_def *
315
316inline union tree_node *
321
322inline union tree_node *
327
328inline gimple *
333
334inline void
335gt_ggc_mx (const char *s)
336{
337 ggc_test_and_set_mark (const_cast<char *> (s));
338}
339
340inline void
341gt_pch_nx (const char *)
342{
343}
344
345inline void gt_pch_nx (bool) { }
346inline void gt_pch_nx (char) { }
347inline void gt_pch_nx (signed char) { }
348inline void gt_pch_nx (unsigned char) { }
349inline void gt_pch_nx (short) { }
350inline void gt_pch_nx (unsigned short) { }
351inline void gt_pch_nx (int) { }
352inline void gt_pch_nx (unsigned int) { }
353inline void gt_pch_nx (long int) { }
354inline void gt_pch_nx (unsigned long int) { }
355inline void gt_pch_nx (long long int) { }
356inline void gt_pch_nx (unsigned long long int) { }
357
358inline void gt_ggc_mx (bool) { }
359inline void gt_ggc_mx (char) { }
360inline void gt_ggc_mx (signed char) { }
361inline void gt_ggc_mx (unsigned char) { }
362inline void gt_ggc_mx (short) { }
363inline void gt_ggc_mx (unsigned short) { }
364inline void gt_ggc_mx (int) { }
365inline void gt_ggc_mx (unsigned int) { }
366inline void gt_ggc_mx (long int) { }
367inline void gt_ggc_mx (unsigned long int) { }
368inline void gt_ggc_mx (long long int) { }
369inline void gt_ggc_mx (unsigned long long int) { }
370
371extern void ggc_common_finalize ();
372
373#endif
void(* gt_pointer_operator)(void *, void *, void *)
Definition coretypes.h:462
void ggc_grow(void)
Definition ggc-none.cc:72
union tree_node * ggc_alloc_tree_node_stat(size_t s CXX_MEM_STAT_INFO)
Definition ggc.h:317
const char * ggc_alloc_string(const char *contents, int length CXX_MEM_STAT_INFO)
Definition stringpool.cc:83
void dump_ggc_loc_statistics()
Definition ggc-common.cc:1247
void init_stringpool(void)
Definition stringpool.cc:48
void(* gt_pointer_walker)(void *)
Definition ggc.h:62
void init_ggc_heuristics(void)
Definition ggc-common.cc:1097
void * ggc_alloc_atomic(size_t s CXX_MEM_STAT_INFO)
Definition ggc.h:246
int gt_pch_note_object(void *, void *, gt_note_pointers, size_t length_override=(size_t) -1)
Definition ggc-common.cc:267
void ggc_free(void *)
Definition genmatch.cc:42
#define ggc_test_and_set_mark(EXPR)
Definition ggc.h:81
void * ggc_internal_alloc(size_t, void(*)(void *), size_t, size_t CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC
Definition ggc-none.cc:44
void gt_ggc_m_S(const void *)
Definition ggc-page.cc:1464
void gt_pch_nx(const char *)
Definition ggc.h:341
T * ggc_alloc(ALONE_CXX_MEM_STAT_INFO)
Definition ggc.h:184
T * ggc_alloc_no_dtor(ALONE_CXX_MEM_STAT_INFO)
Definition ggc.h:200
void gt_pch_note_reorder(void *, void *, gt_handle_reorder)
Definition ggc-common.cc:318
void ggc_print_statistics(void)
Definition ggc-page.cc:2286
void * ggc_realloc(void *, size_t CXX_MEM_STAT_INFO)
bool ggc_set_mark(const void *)
Definition ggc-page.cc:1545
void gt_pch_restore(FILE *f)
Definition ggc-common.cc:744
T * ggc_cleared_vec_alloc(size_t c CXX_MEM_STAT_INFO)
Definition ggc.h:233
bool ggc_protect_identifiers
Definition ggc-common.cc:35
void gt_ggc_mx(const char *s)
Definition ggc.h:335
void(* gt_handle_reorder)(void *, void *, gt_pointer_operator, void *)
Definition ggc.h:43
void gt_clear_caches()
void ggc_delete(T *ptr)
Definition ggc.h:255
T * ggc_vec_alloc(size_t c CXX_MEM_STAT_INFO)
Definition ggc.h:221
bool need_finalization_p()
Definition ggc.h:173
void gt_pch_n_S(const void *)
Definition stringpool.cc:217
void(* gt_note_pointers)(void *, void *, gt_pointer_operator, void *)
Definition ggc.h:35
const struct ggc_root_tab *const gt_ggc_deletable_rtab[]
void ggc_common_finalize()
Definition ggc-common.cc:1312
size_t ggc_round_alloc_size(size_t requested_size)
Definition ggc-none.cc:38
void gt_pch_save(FILE *f)
Definition ggc-common.cc:511
void ggc_register_root_tab(const struct ggc_root_tab *)
Definition ggc-common.cc:60
void ggc_trim(void)
Definition ggc-none.cc:77
void init_ggc(void)
Definition ggc-page.cc:1733
T * ggc_cleared_alloc(ALONE_CXX_MEM_STAT_INFO)
Definition ggc.h:208
void * ggc_internal_cleared_alloc(size_t, void(*)(void *), size_t, size_t CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC
Definition genmatch.cc:37
struct rtx_def * ggc_alloc_rtx_def_stat(size_t s CXX_MEM_STAT_INFO)
Definition ggc.h:311
void gt_pch_note_callback(void *, void *)
Definition ggc-common.cc:300
gimple * ggc_alloc_cleared_gimple_statement_stat(size_t s CXX_MEM_STAT_INFO)
Definition ggc.h:329
ggc_collect
Definition ggc.h:272
@ GGC_COLLECT_FORCE
Definition ggc.h:274
@ GGC_COLLECT_HEURISTIC
Definition ggc.h:273
void stringpool_statistics(void)
Definition stringpool.cc:149
void report_heap_memory_use(void)
Definition ggc-common.cc:1295
const struct ggc_root_tab *const gt_ggc_rtab[]
const struct ggc_root_tab *const gt_pch_scalar_rtab[]
bool ggc_marked_p(const void *)
Definition ggc-page.cc:1581
void gt_pch_n_S2(const void *, size_t)
Definition stringpool.cc:224
union tree_node * ggc_alloc_cleared_tree_node_stat(size_t s CXX_MEM_STAT_INFO)
Definition ggc.h:323
#define ALONE_CXX_MEM_STAT_INFO
Definition statistics.h:57
#define PASS_MEM_STAT
Definition statistics.h:54
#define CXX_MEM_STAT_INFO
Definition statistics.h:58
Definition ggc.h:66
size_t stride
Definition ggc.h:69
void * base
Definition ggc.h:67
gt_pointer_walker pchw
Definition ggc.h:71
gt_pointer_walker cb
Definition ggc.h:70
size_t nelt
Definition ggc.h:68
Definition gimple.h:225
Definition rtl.h:311
#define NULL
Definition system.h:50
static void finalize()
Definition toplev.cc:1994