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 /* generated function to clear caches in gc memory.  */
  58 extern void gt_clear_caches ();
  59
  60 /* Mark the object in the first parameter and anything it points to.  */
  61 typedef void (*gt_pointer_walker) (void *);
  62
  63 /* Structures for the easy way to mark roots.
  64    In an array, terminated by having base == NULL.  */
  65 struct 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.  */
  74 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  75 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  76 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  77 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  78
  79 /* Structure for hash table cache marking.  */
  80 struct htab;
  81 struct ggc_cache_tab {
  82   struct htab * *base;
  83   size_t nelt;
  84   size_t stride;
  85   gt_pointer_walker cb;
  86   gt_pointer_walker pchw;
  87   int (*marked_p) (const void *);
  88 };
  89 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  90 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  91 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  92
  93 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  94    to true.  Otherwise evaluate to false.  */
  95 #define ggc_test_and_set_mark(EXPR) \
  96   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
  97
  98 #define ggc_mark(EXPR)                          \
  99   do {                                          \
 100     const void *const a__ = (EXPR);             \
 101     if (a__ != NULL && a__ != (void *) 1)       \
 102       ggc_set_mark (a__);                       \
 103   } while (0)
 104
 105 /* Actually set the mark on a particular region of memory, but don't
 106    follow pointers.  This function is called by ggc_mark_*.  It
 107    returns zero if the object was not previously marked; nonzero if
 108    the object was already marked, or if, for any other reason,
 109    pointers in this data structure should not be traversed.  */
 110 extern int ggc_set_mark (const void *);
 111
 112 /* Return 1 if P has been marked, zero otherwise.
 113    P must have been allocated by the GC allocator; it mustn't point to
 114    static objects, stack variables, or memory allocated with malloc.  */
 115 extern int ggc_marked_p (const void *);
 116
 117 /* PCH and GGC handling for strings, mostly trivial.  */
 118 extern void gt_pch_n_S (const void *);
 119 extern void gt_ggc_m_S (const void *);
 120
 121 /* End of GTY machinery API.  */
 122
 123 /* Initialize the string pool.  */
 124 extern void init_stringpool (void);
 125
 126 /* Initialize the garbage collector.  */
 127 extern void init_ggc (void);
 128
 129 /* When true, identifier nodes are considered as GC roots.  When
 130    false, identifier nodes are treated like any other GC-allocated
 131    object, and the identifier hash table is treated as a weak
 132    hash.  */
 133 extern bool ggc_protect_identifiers;
 134
 135 /* Write out all GCed objects to F.  */
 136 extern void gt_pch_save (FILE *f);
 137
 138 \f
 139 /* Allocation.  */
 140
 141 /* The internal primitive.  */
 142 extern void *ggc_internal_alloc (size_t, void (*)(void *), size_t,
 143                                  size_t CXX_MEM_STAT_INFO)
 144      ATTRIBUTE_MALLOC;
 145
 146      static inline
 147      void *
 148      ggc_internal_alloc (size_t s CXX_MEM_STAT_INFO)
 149 {
 150   return ggc_internal_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
 151 }
 152
 153 extern size_t ggc_round_alloc_size (size_t requested_size);
 154
 155 /* Allocates cleared memory.  */
 156 extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
 157                                          size_t, size_t
 158                                          CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
 159
 160 static inline
 161 void *
 162 ggc_internal_cleared_alloc (size_t s CXX_MEM_STAT_INFO)
 163 {
 164   return ggc_internal_cleared_alloc (s, NULL, 0, 1 PASS_MEM_STAT);
 165 }
 166
 167 /* Resize a block.  */
 168 extern void *ggc_realloc (void *, size_t CXX_MEM_STAT_INFO);
 169
 170 /* Free a block.  To be used when known for certain it's not reachable.  */
 171 extern void ggc_free (void *);
 172
 173 extern void dump_ggc_loc_statistics (bool);
 174
 175 /* Reallocator.  */
 176 #define GGC_RESIZEVEC(T, P, N) \
 177     ((T *) ggc_realloc ((P), (N) * sizeof (T) MEM_STAT_INFO))
 178
 179 template<typename T>
 180 void
 181 finalize (void *p)
 182 {
 183   static_cast<T *> (p)->~T ();
 184 }
 185
 186 template<typename T>
 187 static inline bool
 188 need_finalization_p ()
 189 {
 190 #if GCC_VERSION >= 4003
 191   return !__has_trivial_destructor (T);
 192 #else
 193   return true;
 194 #endif
 195 }
 196
 197 template<typename T>
 198 static inline T *
 199 ggc_alloc (ALONE_CXX_MEM_STAT_INFO)
 200 {
 201   if (need_finalization_p<T> ())
 202     return static_cast<T *> (ggc_internal_alloc (sizeof (T), finalize<T>, 0, 1
 203                                                  PASS_MEM_STAT));
 204   else
 205     return static_cast<T *> (ggc_internal_alloc (sizeof (T), NULL, 0, 1
 206                                                  PASS_MEM_STAT));
 207 }
 208
 209 template<typename T>
 210 static inline T *
 211 ggc_cleared_alloc (ALONE_CXX_MEM_STAT_INFO)
 212 {
 213   if (need_finalization_p<T> ())
 214     return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T),
 215                                                          finalize<T>, 0, 1
 216                                                          PASS_MEM_STAT));
 217   else
 218     return static_cast<T *> (ggc_internal_cleared_alloc (sizeof (T), NULL, 0, 1
 219                                                          PASS_MEM_STAT));
 220 }
 221
 222 template<typename T>
 223 static inline T *
 224 ggc_vec_alloc (size_t c CXX_MEM_STAT_INFO)
 225 {
 226   if (need_finalization_p<T> ())
 227     return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), finalize<T>,
 228                                                  sizeof (T), c PASS_MEM_STAT));
 229   else
 230     return static_cast<T *> (ggc_internal_alloc (c * sizeof (T), NULL, 0, 0
 231                                                  PASS_MEM_STAT));
 232 }
 233
 234 template<typename T>
 235 static inline T *
 236 ggc_cleared_vec_alloc (size_t c CXX_MEM_STAT_INFO)
 237 {
 238   if (need_finalization_p<T> ())
 239     return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T),
 240                                                          finalize<T>,
 241                                                          sizeof (T), c
 242                                                          PASS_MEM_STAT));
 243   else
 244     return static_cast<T *> (ggc_internal_cleared_alloc (c * sizeof (T), NULL,
 245                                                          0, 0 PASS_MEM_STAT));
 246 }
 247
 248 static inline void *
 249 ggc_alloc_atomic (size_t s CXX_MEM_STAT_INFO)
 250 {
 251     return ggc_internal_alloc (s PASS_MEM_STAT);
 252 }
 253
 254 extern void *ggc_cleared_alloc_htab_ignore_args (size_t, size_t)
 255   ATTRIBUTE_MALLOC;
 256
 257 extern void *ggc_cleared_alloc_ptr_array_two_args (size_t, size_t)
 258   ATTRIBUTE_MALLOC;
 259
 260 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 261   htab_create_typed_alloc (SIZE, HASH, EQ, DEL, \
 262                            ggc_cleared_alloc_htab_ignore_args,          \
 263                            ggc_cleared_alloc_ptr_array_two_args,        \
 264                            ggc_free)
 265
 266 #define splay_tree_new_ggc(COMPARE, ALLOC_TREE, ALLOC_NODE)                  \
 267   splay_tree_new_typed_alloc (COMPARE, NULL, NULL, &ALLOC_TREE, &ALLOC_NODE, \
 268                               &ggc_splay_dont_free, NULL)
 269
 270 extern void *ggc_splay_alloc (int, void *)
 271   ATTRIBUTE_MALLOC;
 272
 273 extern void ggc_splay_dont_free (void *, void *);
 274
 275 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 276    If LENGTH is -1, then CONTENTS is assumed to be a
 277    null-terminated string and the memory sized accordingly.  */
 278 extern const char *ggc_alloc_string (const char *contents, int length
 279                                      CXX_MEM_STAT_INFO);
 280
 281 /* Make a copy of S, in GC-able memory.  */
 282 #define ggc_strdup(S) ggc_alloc_string ((S), -1 MEM_STAT_INFO)
 283
 284 /* Invoke the collector.  Garbage collection occurs only when this
 285    function is called, not during allocations.  */
 286 extern void ggc_collect (void);
 287
 288 /* Assume that all GGC memory is reachable and grow the limits for next collection. */
 289 extern void ggc_grow (void);
 290
 291 /* Register an additional root table.  This can be useful for some
 292    plugins.  Does nothing if the passed pointer is NULL. */
 293 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 294
 295 /* Register an additional cache table.  This can be useful for some
 296    plugins.  Does nothing if the passed pointer is NULL. */
 297 extern void ggc_register_cache_tab (const struct ggc_cache_tab *);
 298
 299 /* Read objects previously saved with gt_pch_save from F.  */
 300 extern void gt_pch_restore (FILE *f);
 301 \f
 302 /* Statistics.  */
 303
 304 /* Print allocation statistics.  */
 305 extern void ggc_print_statistics (void);
 306
 307 extern void stringpool_statistics (void);
 308
 309 /* Heuristics.  */
 310 extern void init_ggc_heuristics (void);
 311
 312 #define ggc_alloc_rtvec_sized(NELT)                             \
 313   (rtvec_def *) ggc_internal_alloc (sizeof (struct rtvec_def)           \
 314                        + ((NELT) - 1) * sizeof (rtx))           \
 315
 316 /* Memory statistics passing versions of some allocators.  Too few of them to
 317    make gengtype produce them, so just define the needed ones here.  */
 318 static inline struct rtx_def *
 319 ggc_alloc_rtx_def_stat (size_t s CXX_MEM_STAT_INFO)
 320 {
 321   return (struct rtx_def *) ggc_internal_alloc (s PASS_MEM_STAT);
 322 }
 323
 324 static inline union tree_node *
 325 ggc_alloc_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
 326 {
 327   return (union tree_node *) ggc_internal_alloc (s PASS_MEM_STAT);
 328 }
 329
 330 static inline union tree_node *
 331 ggc_alloc_cleared_tree_node_stat (size_t s CXX_MEM_STAT_INFO)
 332 {
 333   return (union tree_node *) ggc_internal_cleared_alloc (s PASS_MEM_STAT);
 334 }
 335
 336 static inline struct gimple_statement_base *
 337 ggc_alloc_cleared_gimple_statement_stat (size_t s CXX_MEM_STAT_INFO)
 338 {
 339   return (struct gimple_statement_base *)
 340     ggc_internal_cleared_alloc (s PASS_MEM_STAT);
 341 }
 342
 343 static inline void
 344 gt_ggc_mx (const char *s)
 345 {
 346   ggc_test_and_set_mark (const_cast<char *> (s));
 347 }
 348
 349 static inline void
 350 gt_pch_nx (const char *)
 351 {
 352 }
 353
 354 static inline void
 355 gt_ggc_mx (int)
 356 {
 357 }
 358
 359 static inline void
 360 gt_pch_nx (int)
 361 {
 362 }
 363
 364 static inline void
 365 gt_pch_nx (unsigned int)
 366 {
 367 }
 368
 369 #endif