1/* Garbage collection for the GNU compiler.
2
3   Copyright (C) 1998-2015 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#include "statistics.h"
24
25/* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
26   an external gc library that might be linked in.  */
27
28/* Constants for general use.  */
29extern const char empty_string[];	/* empty string */
30
31/* Internal functions and data structures used by the GTY
32   machinery, including the generated gt*.[hc] files.  */
33
34#include "gtype-desc.h"
35
36/* One of these applies its third parameter (with cookie in the fourth
37   parameter) to each pointer in the object pointed to by the first
38   parameter, using the second parameter.  */
39typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
40				  void *);
41
42/* One of these is called before objects are re-ordered in memory.
43   The first parameter is the original object, the second is the
44   subobject that has had its pointers reordered, the third parameter
45   can compute the new values of a pointer when given the cookie in
46   the fourth parameter.  */
47typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
48				   void *);
49
50/* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
51extern int gt_pch_note_object (void *, void *, gt_note_pointers);
52
53/* Used by the gt_pch_n_* routines.  Register that an object has a reorder
54   function.  */
55extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
56
57/* generated function to clear caches in gc memory.  */
58extern void gt_clear_caches ();
59
60/* Mark the object in the first parameter and anything it points to.  */
61typedef void (*gt_pointer_walker) (void *);
62
63/* Structures for the easy way to mark roots.
64   In an array, terminated by having base == NULL.  */
65struct ggc_root_tab {
66  void *base;
67  size_t nelt;
68  size_t stride;
69  gt_pointer_walker cb;
70  gt_pointer_walker pchw;
71};
72#define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
73/* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
74extern const struct ggc_root_tab * const gt_ggc_rtab[];
75extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
76extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
77
78/* If EXPR is not NULL and previously unmarked, mark it and evaluate
79   to true.  Otherwise evaluate to false.  */
80#define ggc_test_and_set_mark(EXPR) \
81  ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
82
83#define ggc_mark(EXPR)				\
84  do {						\
85    const void *const a__ = (EXPR);		\
86    if (a__ != NULL && a__ != (void *) 1)	\
87      ggc_set_mark (a__);			\
88  } while (0)
89
90/* Actually set the mark on a particular region of memory, but don't
91   follow pointers.  This function is called by ggc_mark_*.  It
92   returns zero if the object was not previously marked; nonzero if
93   the object was already marked, or if, for any other reason,
94   pointers in this data structure should not be traversed.  */
95extern int ggc_set_mark	(const void *);
96
97/* Return 1 if P has been marked, zero otherwise.
98   P must have been allocated by the GC allocator; it mustn't point to
99   static objects, stack variables, or memory allocated with malloc.  */
100extern int ggc_marked_p	(const void *);
101
102/* PCH and GGC handling for strings, mostly trivial.  */
103extern void gt_pch_n_S (const void *);
104extern void gt_ggc_m_S (const void *);
105
106/* End of GTY machinery API.  */
107
108/* Initialize the string pool.  */
109extern void init_stringpool (void);
110
111/* Initialize the garbage collector.  */
112extern void init_ggc (void);
113
114/* When true, identifier nodes are considered as GC roots.  When
115   false, identifier nodes are treated like any other GC-allocated
116   object, and the identifier hash table is treated as a weak
117   hash.  */
118extern bool ggc_protect_identifiers;
119
120/* Write out all GCed objects to F.  */
121extern void gt_pch_save (FILE *f);
122
123
124/* Allocation.  */
125
126/* The internal primitive.  */
127extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
128				 size_t CXX_MEM_STAT_INFO)
129     ATTRIBUTE_MALLOC;
130
131     static inline
132     void *
133     ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
134{
135  return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
136}
137
138extern size_t ggc_round_alloc_size (size_t requested_size);
139
140/* Allocates cleared memory.  */
141extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
142					 size_t, size_t
143					 CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
144
145static inline
146void *
147ggc_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.  */
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 (bool);
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>
172static inline bool
173need_finalization_p ()
174{
175#if GCC_VERSION >= 4003
176  return !__has_trivial_destructor (T);
177#else
178  return true;
179#endif
180}
181
182template<typename T>
183static inline T *
184ggc_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
194template<typename T>
195static inline T *
196ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
197{
198  if (need_finalization_p<T> ())
199    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
200							 finalize<T>, 0, 1
201							 PASS_MEM_STAT));
202  else
203    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
204							 PASS_MEM_STAT));
205}
206
207template<typename T>
208static inline T *
209ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
210{
211  if (need_finalization_p<T> ())
212    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
213						 sizeof (T), c PASS_MEM_STAT));
214  else
215    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), NULL, 0, 0
216						 PASS_MEM_STAT));
217}
218
219template<typename T>
220static inline T *
221ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
222{
223  if (need_finalization_p<T> ())
224    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
225							 finalize<T>,
226							 sizeof (T), c
227							 PASS_MEM_STAT));
228  else
229    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
230							 0, 0 PASS_MEM_STAT));
231}
232
233static inline void *
234ggc_alloc_atomic (size_t s CXX_MEM_STAT_INFO)
235{
236    return ggc_internal_alloc (s PASS_MEM_STAT);
237}
238
239/* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
240   If LENGTH is -1, then CONTENTS is assumed to be a
241   null-terminated string and the memory sized accordingly.  */
242extern const char *ggc_alloc_string (const char *contents, int length
243                                     CXX_MEM_STAT_INFO);
244
245/* Make a copy of S, in GC-able memory.  */
246#define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
247
248/* Invoke the collector.  Garbage collection occurs only when this
249   function is called, not during allocations.  */
250extern void ggc_collect	(void);
251
252/* Assume that all GGC memory is reachable and grow the limits for next collection. */
253extern void ggc_grow (void);
254
255/* Register an additional root table.  This can be useful for some
256   plugins.  Does nothing if the passed pointer is NULL. */
257extern void ggc_register_root_tab (const struct ggc_root_tab *);
258
259/* Read objects previously saved with gt_pch_save from F.  */
260extern void gt_pch_restore (FILE *f);
261
262/* Statistics.  */
263
264/* Print allocation statistics.  */
265extern void ggc_print_statistics (void);
266
267extern void stringpool_statistics (void);
268
269/* Heuristics.  */
270extern void init_ggc_heuristics (void);
271
272#define ggc_alloc_rtvec_sized(NELT)				\
273  (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def)		\
274		       + ((NELT) - 1) * sizeof (rtx))		\
275
276/* Memory statistics passing versions of some allocators.  Too few of them to
277   make gengtype produce them, so just define the needed ones here.  */
278static inline struct rtx_def *
279ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
280{
281  return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
282}
283
284static inline union tree_node *
285ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
286{
287  return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
288}
289
290static inline union tree_node *
291ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
292{
293  return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
294}
295
296static inline struct gimple_statement_base *
297ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
298{
299  return (struct gimple_statement_base *)
300    ggc_internal_cleared_alloc (s PASS_MEM_STAT);
301}
302
303static inline void
304gt_ggc_mx (const char *s)
305{
306  ggc_test_and_set_mark (const_cast<char *> (s));
307}
308
309static inline void
310gt_pch_nx (const char *)
311{
312}
313
314static inline void
315gt_ggc_mx (int)
316{
317}
318
319static inline void
320gt_pch_nx (int)
321{
322}
323
324static inline void
325gt_pch_nx (unsigned int)
326{
327}
328
329#endif
330