1/* Garbage collection for the GNU compiler.
2
3   Copyright (C) 1998-2020 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
49/* Used by the gt_pch_n_* routines.  Register that an object has a reorder
50   function.  */
51extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
52
53/* generated function to clear caches in gc memory.  */
54extern void gt_clear_caches ();
55
56/* Mark the object in the first parameter and anything it points to.  */
57typedef void (*gt_pointer_walker) (void *);
58
59/* Structures for the easy way to mark roots.
60   In an array, terminated by having base == NULL.  */
61struct ggc_root_tab {
62  void *base;
63  size_t nelt;
64  size_t stride;
65  gt_pointer_walker cb;
66  gt_pointer_walker pchw;
67};
68#define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
69/* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
70extern const struct ggc_root_tab * const gt_ggc_rtab[];
71extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
72extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
73
74/* If EXPR is not NULL and previously unmarked, mark it and evaluate
75   to true.  Otherwise evaluate to false.  */
76#define ggc_test_and_set_mark(EXPR) \
77  ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
78
79#define ggc_mark(EXPR)				\
80  do {						\
81    const void *const a__ = (EXPR);		\
82    if (a__ != NULL && a__ != (void *) 1)	\
83      ggc_set_mark (a__);			\
84  } while (0)
85
86/* Actually set the mark on a particular region of memory, but don't
87   follow pointers.  This function is called by ggc_mark_*.  It
88   returns zero if the object was not previously marked; nonzero if
89   the object was already marked, or if, for any other reason,
90   pointers in this data structure should not be traversed.  */
91extern int ggc_set_mark	(const void *);
92
93/* Return 1 if P has been marked, zero otherwise.
94   P must have been allocated by the GC allocator; it mustn't point to
95   static objects, stack variables, or memory allocated with malloc.  */
96extern int ggc_marked_p	(const void *);
97
98/* PCH and GGC handling for strings, mostly trivial.  */
99extern void gt_pch_n_S (const void *);
100extern void gt_ggc_m_S (const void *);
101
102/* End of GTY machinery API.  */
103
104/* Initialize the string pool.  */
105extern void init_stringpool (void);
106
107/* Initialize the garbage collector.  */
108extern void init_ggc (void);
109
110/* When true, identifier nodes are considered as GC roots.  When
111   false, identifier nodes are treated like any other GC-allocated
112   object, and the identifier hash table is treated as a weak
113   hash.  */
114extern bool ggc_protect_identifiers;
115
116/* Write out all GCed objects to F.  */
117extern void gt_pch_save (FILE *f);
118
119
120/* Allocation.  */
121
122/* The internal primitive.  */
123extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
124				 size_t CXX_MEM_STAT_INFO)
125     ATTRIBUTE_MALLOC;
126
127inline void *
128ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
129{
130  return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
131}
132
133extern size_t ggc_round_alloc_size (size_t requested_size);
134
135/* Allocates cleared memory.  */
136extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
137					 size_t, size_t
138					 CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
139
140inline void *
141ggc_internal_cleared_alloc (size_t s CXX_MEM_STAT_INFO)
142{
143  return ggc_internal_cleared_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
144}
145
146/* Resize a block.  */
147extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
148
149/* Free a block.  To be used when known for certain it's not reachable.  */
150extern void ggc_free (void *);
151
152extern void dump_ggc_loc_statistics ();
153
154/* Reallocator.  */
155#define GGC_RESIZEVEC(T, P, N) \
156    ((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
157
158template<typename T>
159void
160finalize (void *p)
161{
162  static_cast<T *> (p)->~T ();
163}
164
165template<typename T>
166inline bool
167need_finalization_p ()
168{
169#if GCC_VERSION >= 4003
170  return !__has_trivial_destructor (T);
171#else
172  return true;
173#endif
174}
175
176template<typename T>
177inline T *
178ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
179{
180  if (need_finalization_p<T> ())
181    return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
182						 PASS_MEM_STAT));
183  else
184    return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
185						 PASS_MEM_STAT));
186}
187
188/* GGC allocation function that does not call finalizer for type
189   that have need_finalization_p equal to true.  User is responsible
190   for calling of the destructor.  */
191
192template<typename T>
193inline T *
194ggc_alloc_no_dtor (ALONE_CXX_MEM_STAT_INFO)
195{
196  return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
197					       PASS_MEM_STAT));
198}
199
200template<typename T>
201inline T *
202ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
203{
204  if (need_finalization_p<T> ())
205    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
206							 finalize<T>, 0, 1
207							 PASS_MEM_STAT));
208  else
209    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
210							 PASS_MEM_STAT));
211}
212
213template<typename T>
214inline T *
215ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
216{
217  if (need_finalization_p<T> ())
218    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
219						 sizeof (T), c PASS_MEM_STAT));
220  else
221    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), NULL, 0, 0
222						 PASS_MEM_STAT));
223}
224
225template<typename T>
226inline T *
227ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
228{
229  if (need_finalization_p<T> ())
230    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
231							 finalize<T>,
232							 sizeof (T), c
233							 PASS_MEM_STAT));
234  else
235    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
236							 0, 0 PASS_MEM_STAT));
237}
238
239inline void *
240ggc_alloc_atomic (size_t s CXX_MEM_STAT_INFO)
241{
242    return ggc_internal_alloc (s PASS_MEM_STAT);
243}
244
245/* Call destructor and free the garbage collected memory.  */
246
247template <typename T>
248inline void
249ggc_delete (T *ptr)
250{
251  ptr->~T ();
252  ggc_free (ptr);
253}
254
255/* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
256   If LENGTH is -1, then CONTENTS is assumed to be a
257   null-terminated string and the memory sized accordingly.  */
258extern const char *ggc_alloc_string (const char *contents, int length
259                                     CXX_MEM_STAT_INFO);
260
261/* Make a copy of S, in GC-able memory.  */
262#define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
263
264/* Invoke the collector.  Garbage collection occurs only when this
265   function is called, not during allocations.  */
266extern void ggc_collect	(void);
267
268/* Return unused memory pages to the system.  */
269extern void ggc_trim (void);
270
271/* Assume that all GGC memory is reachable and grow the limits for next collection. */
272extern void ggc_grow (void);
273
274/* Register an additional root table.  This can be useful for some
275   plugins.  Does nothing if the passed pointer is NULL. */
276extern void ggc_register_root_tab (const struct ggc_root_tab *);
277
278/* Read objects previously saved with gt_pch_save from F.  */
279extern void gt_pch_restore (FILE *f);
280
281/* Statistics.  */
282
283/* Print allocation statistics.  */
284extern void ggc_print_statistics (void);
285
286extern void stringpool_statistics (void);
287
288/* Heuristics.  */
289extern void init_ggc_heuristics (void);
290
291/* Report current heap memory use to stderr.  */
292extern void report_heap_memory_use (void);
293
294#define ggc_alloc_rtvec_sized(NELT)				\
295  (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def)		\
296		       + ((NELT) - 1) * sizeof (rtx))		\
297
298/* Memory statistics passing versions of some allocators.  Too few of them to
299   make gengtype produce them, so just define the needed ones here.  */
300inline struct rtx_def *
301ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
302{
303  return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
304}
305
306inline union tree_node *
307ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
308{
309  return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
310}
311
312inline union tree_node *
313ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
314{
315  return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
316}
317
318inline gimple *
319ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
320{
321  return (gimple *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
322}
323
324inline void
325gt_ggc_mx (const char *s)
326{
327  ggc_test_and_set_mark (const_cast<char *> (s));
328}
329
330inline void
331gt_pch_nx (const char *)
332{
333}
334
335inline void
336gt_ggc_mx (int)
337{
338}
339
340inline void
341gt_pch_nx (int)
342{
343}
344
345inline void
346gt_pch_nx (unsigned int)
347{
348}
349
350#endif
351