ggc.h revision 1.6 
1/* Garbage collection for the GNU compiler.
2
3   Copyright (C) 1998-2016 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/* Constants for general use.  */
28extern const char empty_string[];	/* empty string */
29
30/* Internal functions and data structures used by the GTY
31   machinery, including the generated gt*.[hc] files.  */
32
33#include "gtype-desc.h"
34
35/* One of these applies its third parameter (with cookie in the fourth
36   parameter) to each pointer in the object pointed to by the first
37   parameter, using the second parameter.  */
38typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
39				  void *);
40
41/* One of these is called before objects are re-ordered in memory.
42   The first parameter is the original object, the second is the
43   subobject that has had its pointers reordered, the third parameter
44   can compute the new values of a pointer when given the cookie in
45   the fourth parameter.  */
46typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
47				   void *);
48
49/* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
50extern int gt_pch_note_object (void *, void *, gt_note_pointers);
51
52/* Used by the gt_pch_n_* routines.  Register that an object has a reorder
53   function.  */
54extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
55
56/* generated function to clear caches in gc memory.  */
57extern void gt_clear_caches ();
58
59/* Mark the object in the first parameter and anything it points to.  */
60typedef void (*gt_pointer_walker) (void *);
61
62/* Structures for the easy way to mark roots.
63   In an array, terminated by having base == NULL.  */
64struct ggc_root_tab {
65  void *base;
66  size_t nelt;
67  size_t stride;
68  gt_pointer_walker cb;
69  gt_pointer_walker pchw;
70};
71#define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
72/* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
73extern const struct ggc_root_tab * const gt_ggc_rtab[];
74extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
75extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
76
77/* If EXPR is not NULL and previously unmarked, mark it and evaluate
78   to true.  Otherwise evaluate to false.  */
79#define ggc_test_and_set_mark(EXPR) \
80  ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
81
82#define ggc_mark(EXPR)				\
83  do {						\
84    const void *const a__ = (EXPR);		\
85    if (a__ != NULL && a__ != (void *) 1)	\
86      ggc_set_mark (a__);			\
87  } while (0)
88
89/* Actually set the mark on a particular region of memory, but don't
90   follow pointers.  This function is called by ggc_mark_*.  It
91   returns zero if the object was not previously marked; nonzero if
92   the object was already marked, or if, for any other reason,
93   pointers in this data structure should not be traversed.  */
94extern int ggc_set_mark	(const void *);
95
96/* Return 1 if P has been marked, zero otherwise.
97   P must have been allocated by the GC allocator; it mustn't point to
98   static objects, stack variables, or memory allocated with malloc.  */
99extern int ggc_marked_p	(const void *);
100
101/* PCH and GGC handling for strings, mostly trivial.  */
102extern void gt_pch_n_S (const void *);
103extern void gt_ggc_m_S (const void *);
104
105/* End of GTY machinery API.  */
106
107/* Initialize the string pool.  */
108extern void init_stringpool (void);
109
110/* Initialize the garbage collector.  */
111extern void init_ggc (void);
112
113/* When true, identifier nodes are considered as GC roots.  When
114   false, identifier nodes are treated like any other GC-allocated
115   object, and the identifier hash table is treated as a weak
116   hash.  */
117extern bool ggc_protect_identifiers;
118
119/* Write out all GCed objects to F.  */
120extern void gt_pch_save (FILE *f);
121
122
123/* Allocation.  */
124
125/* The internal primitive.  */
126extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
127				 size_t CXX_MEM_STAT_INFO)
128     ATTRIBUTE_MALLOC;
129
130     static inline
131     void *
132     ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
133{
134  return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
135}
136
137extern size_t ggc_round_alloc_size (size_t requested_size);
138
139/* Allocates cleared memory.  */
140extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
141					 size_t, size_t
142					 CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
143
144static inline
145void *
146ggc_internal_cleared_alloc (size_t s CXX_MEM_STAT_INFO)
147{
148  return ggc_internal_cleared_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
149}
150
151/* Resize a block.  */
152extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
153
154/* Free a block.  To be used when known for certain it's not reachable.  */
155extern void ggc_free (void *);
156
157extern void dump_ggc_loc_statistics (bool);
158
159/* Reallocator.  */
160#define GGC_RESIZEVEC(T, P, N) \
161    ((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
162
163template<typename T>
164void
165finalize (void *p)
166{
167  static_cast<T *> (p)->~T ();
168}
169
170template<typename T>
171static inline bool
172need_finalization_p ()
173{
174#if GCC_VERSION >= 4003
175  return !__has_trivial_destructor (T);
176#else
177  return true;
178#endif
179}
180
181template<typename T>
182static inline T *
183ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
184{
185  if (need_finalization_p<T> ())
186    return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
187						 PASS_MEM_STAT));
188  else
189    return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
190						 PASS_MEM_STAT));
191}
192
193template<typename T>
194static inline T *
195ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
196{
197  if (need_finalization_p<T> ())
198    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
199							 finalize<T>, 0, 1
200							 PASS_MEM_STAT));
201  else
202    return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
203							 PASS_MEM_STAT));
204}
205
206template<typename T>
207static inline T *
208ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
209{
210  if (need_finalization_p<T> ())
211    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
212						 sizeof (T), c PASS_MEM_STAT));
213  else
214    return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), NULL, 0, 0
215						 PASS_MEM_STAT));
216}
217
218template<typename T>
219static inline T *
220ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
221{
222  if (need_finalization_p<T> ())
223    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
224							 finalize<T>,
225							 sizeof (T), c
226							 PASS_MEM_STAT));
227  else
228    return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
229							 0, 0 PASS_MEM_STAT));
230}
231
232static inline void *
233ggc_alloc_atomic (size_t s CXX_MEM_STAT_INFO)
234{
235    return ggc_internal_alloc (s PASS_MEM_STAT);
236}
237
238/* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
239   If LENGTH is -1, then CONTENTS is assumed to be a
240   null-terminated string and the memory sized accordingly.  */
241extern const char *ggc_alloc_string (const char *contents, int length
242                                     CXX_MEM_STAT_INFO);
243
244/* Make a copy of S, in GC-able memory.  */
245#define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
246
247/* Invoke the collector.  Garbage collection occurs only when this
248   function is called, not during allocations.  */
249extern void ggc_collect	(void);
250
251/* Assume that all GGC memory is reachable and grow the limits for next collection. */
252extern void ggc_grow (void);
253
254/* Register an additional root table.  This can be useful for some
255   plugins.  Does nothing if the passed pointer is NULL. */
256extern void ggc_register_root_tab (const struct ggc_root_tab *);
257
258/* Read objects previously saved with gt_pch_save from F.  */
259extern void gt_pch_restore (FILE *f);
260
261/* Statistics.  */
262
263/* Print allocation statistics.  */
264extern void ggc_print_statistics (void);
265
266extern void stringpool_statistics (void);
267
268/* Heuristics.  */
269extern void init_ggc_heuristics (void);
270
271#define ggc_alloc_rtvec_sized(NELT)				\
272  (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def)		\
273		       + ((NELT) - 1) * sizeof (rtx))		\
274
275/* Memory statistics passing versions of some allocators.  Too few of them to
276   make gengtype produce them, so just define the needed ones here.  */
277static inline struct rtx_def *
278ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
279{
280  return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
281}
282
283static inline union tree_node *
284ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
285{
286  return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
287}
288
289static inline union tree_node *
290ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
291{
292  return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
293}
294
295static inline gimple *
296ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
297{
298  return (gimple *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
299}
300
301static inline void
302gt_ggc_mx (const char *s)
303{
304  ggc_test_and_set_mark (const_cast<char *> (s));
305}
306
307static inline void
308gt_pch_nx (const char *)
309{
310}
311
312static inline void
313gt_ggc_mx (int)
314{
315}
316
317static inline void
318gt_pch_nx (int)
319{
320}
321
322static inline void
323gt_pch_nx (unsigned int)
324{
325}
326
327#endif
328