gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2
   3    Copyright (C) 1998-2015 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_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.  */
  95 extern 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.  */
 100 extern int ggc_marked_p (const void *);
 101
 102 /* PCH and GGC handling for strings, mostly trivial.  */
 103 extern void gt_pch_n_S (const void *);
 104 extern void gt_ggc_m_S (const void *);
 105
 106 /* End of GTY machinery API.  */
 107
 108 /* Initialize the string pool.  */
 109 extern void init_stringpool (void);
 110
 111 /* Initialize the garbage collector.  */
 112 extern 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.  */
 118 extern bool ggc_protect_identifiers;
 119
 120 /* Write out all GCed objects to F.  */
 121 extern void gt_pch_save (FILE *f);
 122
 123 \f
 124 /* Allocation.  */
 125
 126 /* The internal primitive.  */
 127 extern 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
 138 extern size_t ggc_round_alloc_size (size_t requested_size);
 139
 140 /* Allocates cleared memory.  */
 141 extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
 142                                          size_t, size_t
 143                                          CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
 144
 145 static inline
 146 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 (bool);
 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 static 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 static 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 template<typename T>
 195 static inline T *
 196 ggc_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
 207 template<typename T>
 208 static inline T *
 209 ggc_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
 219 template<typename T>
 220 static inline T *
 221 ggc_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
 233 static inline void *
 234 ggc_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.  */
 242 extern 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.  */
 250 extern void ggc_collect (void);
 251
 252 /* Assume that all GGC memory is reachable and grow the limits for next collection. */
 253 extern 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. */
 257 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 258
 259 /* Read objects previously saved with gt_pch_save from F.  */
 260 extern void gt_pch_restore (FILE *f);
 261 \f
 262 /* Statistics.  */
 263
 264 /* Print allocation statistics.  */
 265 extern void ggc_print_statistics (void);
 266
 267 extern void stringpool_statistics (void);
 268
 269 /* Heuristics.  */
 270 extern 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.  */
 278 static inline struct rtx_def *
 279 ggc_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
 284 static inline union tree_node *
 285 ggc_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
 290 static inline union tree_node *
 291 ggc_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
 296 static inline struct gimple_statement_base *
 297 ggc_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
 303 static inline void
 304 gt_ggc_mx (const char *s)
 305 {
 306   ggc_test_and_set_mark (const_cast<char *> (s));
 307 }
 308
 309 static inline void
 310 gt_pch_nx (const char *)
 311 {
 312 }
 313
 314 static inline void
 315 gt_ggc_mx (int)
 316 {
 317 }
 318
 319 static inline void
 320 gt_pch_nx (int)
 321 {
 322 }
 323
 324 static inline void
 325 gt_pch_nx (unsigned int)
 326 {
 327 }
 328
 329 #endif