gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2
   3    Copyright (C) 1998-2014 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 #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.  */
  29 extern 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.  */
  39 typedef 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.  */
  47 typedef 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.  */
  51 extern 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.  */
  55 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  56
  57 /* Mark the object in the first parameter and anything it points to.  */
  58 typedef void (*gt_pointer_walker) (void *);
  59
  60 /* Structures for the easy way to mark roots.
  61    In an array, terminated by having base == NULL.  */
  62 struct ggc_root_tab {
  63   void *base;
  64   size_t nelt;
  65   size_t stride;
  66   gt_pointer_walker cb;
  67   gt_pointer_walker pchw;
  68 };
  69 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
  70 /* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
  71 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  72 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  73 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  74 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  75
  76 /* Structure for hash table cache marking.  */
  77 struct htab;
  78 struct ggc_cache_tab {
  79   struct htab * *base;
  80   size_t nelt;
  81   size_t stride;
  82   gt_pointer_walker cb;
  83   gt_pointer_walker pchw;
  84   int (*marked_p) (const void *);
  85 };
  86 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  87 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  88 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  89
  90 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  91    to true.  Otherwise evaluate to false.  */
  92 #define ggc_test_and_set_mark(EXPR) \
  93   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
  94
  95 #define ggc_mark(EXPR)                          \
  96   do {                                          \
  97     const void *const a__ = (EXPR);             \
  98     if (a__ != NULL && a__ != (void *) 1)       \
  99       ggc_set_mark (a__);                       \
 100   } while (0)
 101
 102 /* Actually set the mark on a particular region of memory, but don't
 103    follow pointers.  This function is called by ggc_mark_*.  It
 104    returns zero if the object was not previously marked; nonzero if
 105    the object was already marked, or if, for any other reason,
 106    pointers in this data structure should not be traversed.  */
 107 extern int ggc_set_mark (const void *);
 108
 109 /* Return 1 if P has been marked, zero otherwise.
 110    P must have been allocated by the GC allocator; it mustn't point to
 111    static objects, stack variables, or memory allocated with malloc.  */
 112 extern int ggc_marked_p (const void *);
 113
 114 /* PCH and GGC handling for strings, mostly trivial.  */
 115 extern void gt_pch_n_S (const void *);
 116 extern void gt_ggc_m_S (const void *);
 117
 118 /* End of GTY machinery API.  */
 119
 120 /* Initialize the string pool.  */
 121 extern void init_stringpool (void);
 122
 123 /* Initialize the garbage collector.  */
 124 extern void init_ggc (void);
 125
 126 /* When true, identifier nodes are considered as GC roots.  When
 127    false, identifier nodes are treated like any other GC-allocated
 128    object, and the identifier hash table is treated as a weak
 129    hash.  */
 130 extern bool ggc_protect_identifiers;
 131
 132 /* Write out all GCed objects to F.  */
 133 extern void gt_pch_save (FILE *f);
 134
 135 \f
 136 /* Allocation.  */
 137
 138 /* The internal primitive.  */
 139 extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
 140                                  size_t CXX_MEM_STAT_INFO)
 141      ATTRIBUTE_MALLOC;
 142
 143      static inline
 144      void *
 145      ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
 146 {
 147   return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
 148 }
 149
 150 extern size_t ggc_round_alloc_size (size_t requested_size);
 151
 152 /* Allocates cleared memory.  */
 153 extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
 154                                          size_t, size_t
 155                                          CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
 156
 157 static inline
 158 void *
 159 ggc_internal_cleared_alloc (size_t s CXX_MEM_STAT_INFO)
 160 {
 161   return ggc_internal_cleared_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
 162 }
 163
 164 /* Resize a block.  */
 165 extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
 166
 167 /* Free a block.  To be used when known for certain it's not reachable.  */
 168 extern void ggc_free (void *);
 169
 170 extern void dump_ggc_loc_statistics (bool);
 171
 172 /* Reallocator.  */
 173 #define GGC_RESIZEVEC(T, P, N) \
 174     ((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
 175
 176 template<typename T>
 177 void
 178 finalize (void *p)
 179 {
 180   static_cast<T *> (p)->~T ();
 181 }
 182
 183 template<typename T>
 184 static inline bool
 185 need_finalization_p ()
 186 {
 187 #if GCC_VERSION >= 4003
 188   return !__has_trivial_destructor (T);
 189 #else
 190   return true;
 191 #endif
 192 }
 193
 194 template<typename T>
 195 static inline T *
 196 ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
 197 {
 198   if (need_finalization_p<T> ())
 199     return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
 200                                                  PASS_MEM_STAT));
 201   else
 202     return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
 203                                                  PASS_MEM_STAT));
 204 }
 205
 206 template<typename T>
 207 static 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 static 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 static 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 static 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 extern void *ggc_cleared_alloc_htab_ignore_args (size_t, size_t)
 252   ATTRIBUTE_MALLOC;
 253
 254 extern void *ggc_cleared_alloc_ptr_array_two_args (size_t, size_t)
 255   ATTRIBUTE_MALLOC;
 256
 257 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 258   htab_create_typed_alloc (SIZE, HASH, EQ, DEL, \
 259                            ggc_cleared_alloc_htab_ignore_args,          \
 260                            ggc_cleared_alloc_ptr_array_two_args,        \
 261                            ggc_free)
 262
 263 #define splay_tree_new_ggc(COMPARE, ALLOC_TREE, ALLOC_NODE)                  \
 264   splay_tree_new_typed_alloc (COMPARE, NULL, NULL, &ALLOC_TREE, &ALLOC_NODE, \
 265                               &ggc_splay_dont_free, NULL)
 266
 267 extern void *ggc_splay_alloc (int, void *)
 268   ATTRIBUTE_MALLOC;
 269
 270 extern void ggc_splay_dont_free (void *, void *);
 271
 272 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 273    If LENGTH is -1, then CONTENTS is assumed to be a
 274    null-terminated string and the memory sized accordingly.  */
 275 extern const char *ggc_alloc_string (const char *contents, int length
 276                                      CXX_MEM_STAT_INFO);
 277
 278 /* Make a copy of S, in GC-able memory.  */
 279 #define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
 280
 281 /* Invoke the collector.  Garbage collection occurs only when this
 282    function is called, not during allocations.  */
 283 extern void ggc_collect (void);
 284
 285 /* Assume that all GGC memory is reachable and grow the limits for next collection. */
 286 extern void ggc_grow (void);
 287
 288 /* Register an additional root table.  This can be useful for some
 289    plugins.  Does nothing if the passed pointer is NULL. */
 290 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 291
 292 /* Register an additional cache table.  This can be useful for some
 293    plugins.  Does nothing if the passed pointer is NULL. */
 294 extern void ggc_register_cache_tab (const struct ggc_cache_tab *);
 295
 296 /* Read objects previously saved with gt_pch_save from F.  */
 297 extern void gt_pch_restore (FILE *f);
 298 \f
 299 /* Statistics.  */
 300
 301 /* Print allocation statistics.  */
 302 extern void ggc_print_statistics (void);
 303
 304 extern void stringpool_statistics (void);
 305
 306 /* Heuristics.  */
 307 extern void init_ggc_heuristics (void);
 308
 309 #define ggc_alloc_rtvec_sized(NELT)                             \
 310   (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def)           \
 311                        + ((NELT) - 1) * sizeof (rtx))           \
 312
 313 /* Memory statistics passing versions of some allocators.  Too few of them to
 314    make gengtype produce them, so just define the needed ones here.  */
 315 static inline struct rtx_def *
 316 ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
 317 {
 318   return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
 319 }
 320
 321 static inline union tree_node *
 322 ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
 323 {
 324   return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
 325 }
 326
 327 static inline union tree_node *
 328 ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
 329 {
 330   return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
 331 }
 332
 333 static inline struct gimple_statement_base *
 334 ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
 335 {
 336   return (struct gimple_statement_base *)
 337     ggc_internal_cleared_alloc (s PASS_MEM_STAT);
 338 }
 339
 340 static inline void
 341 gt_ggc_mx (const char *s)
 342 {
 343   ggc_test_and_set_mark (const_cast<char *> (s));
 344 }
 345
 346 static inline void
 347 gt_pch_nx (const char *)
 348 {
 349 }
 350
 351 static inline void
 352 gt_ggc_mx (int)
 353 {
 354 }
 355
 356 static inline void
 357 gt_pch_nx (int)
 358 {
 359 }
 360
 361 static inline void
 362 gt_pch_nx (unsigned int)
 363 {
 364 }
 365
 366 #endif