gcc/ggc.h

   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 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.  */
  96 extern 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.  */
 101 extern bool 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 \f
 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 \f
 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 extern void ggc_common_finalize ();
 372
 373 #endif