gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2
   3    Copyright (C) 1998-2017 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 /* Constants for general use.  */
  28 extern 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.  */
  38 typedef 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.  */
  46 typedef 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.  */
  50 extern 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.  */
  54 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  55
  56 /* generated function to clear caches in gc memory.  */
  57 extern void gt_clear_caches ();
  58
  59 /* Mark the object in the first parameter and anything it points to.  */
  60 typedef void (*gt_pointer_walker) (void *);
  61
  62 /* Structures for the easy way to mark roots.
  63    In an array, terminated by having base == NULL.  */
  64 struct 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.  */
  73 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  74 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  75 extern 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.  */
  94 extern 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.  */
  99 extern int ggc_marked_p (const void *);
 100
 101 /* PCH and GGC handling for strings, mostly trivial.  */
 102 extern void gt_pch_n_S (const void *);
 103 extern void gt_ggc_m_S (const void *);
 104
 105 /* End of GTY machinery API.  */
 106
 107 /* Initialize the string pool.  */
 108 extern void init_stringpool (void);
 109
 110 /* Initialize the garbage collector.  */
 111 extern 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.  */
 117 extern bool ggc_protect_identifiers;
 118
 119 /* Write out all GCed objects to F.  */
 120 extern void gt_pch_save (FILE *f);
 121
 122 \f
 123 /* Allocation.  */
 124
 125 /* The internal primitive.  */
 126 extern 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
 137 extern size_t ggc_round_alloc_size (size_t requested_size);
 138
 139 /* Allocates cleared memory.  */
 140 extern void *ggc_internal_cleared_alloc (size_t, void (*)(void *),
 141                                          size_t, size_t
 142                                          CXX_MEM_STAT_INFO) ATTRIBUTE_MALLOC;
 143
 144 static inline
 145 void *
 146 ggc_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.  */
 152 extern 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.  */
 155 extern void ggc_free (void *);
 156
 157 extern 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
 163 template<typename T>
 164 void
 165 finalize (void *p)
 166 {
 167   static_cast<T *> (p)->~T ();
 168 }
 169
 170 template<typename T>
 171 static inline bool
 172 need_finalization_p ()
 173 {
 174 #if GCC_VERSION >= 4003
 175   return !__has_trivial_destructor (T);
 176 #else
 177   return true;
 178 #endif
 179 }
 180
 181 template<typename T>
 182 static inline T *
 183 ggc_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
 193 template<typename T>
 194 static inline T *
 195 ggc_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
 206 template<typename T>
 207 static inline T *
 208 ggc_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
 218 template<typename T>
 219 static inline T *
 220 ggc_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
 232 static inline void *
 233 ggc_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.  */
 241 extern 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.  */
 249 extern void ggc_collect (void);
 250
 251 /* Assume that all GGC memory is reachable and grow the limits for next collection. */
 252 extern 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. */
 256 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 257
 258 /* Read objects previously saved with gt_pch_save from F.  */
 259 extern void gt_pch_restore (FILE *f);
 260 \f
 261 /* Statistics.  */
 262
 263 /* Print allocation statistics.  */
 264 extern void ggc_print_statistics (void);
 265
 266 extern void stringpool_statistics (void);
 267
 268 /* Heuristics.  */
 269 extern 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.  */
 277 static inline struct rtx_def *
 278 ggc_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
 283 static inline union tree_node *
 284 ggc_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
 289 static inline union tree_node *
 290 ggc_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
 295 static inline gimple *
 296 ggc_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
 301 static inline void
 302 gt_ggc_mx (const char *s)
 303 {
 304   ggc_test_and_set_mark (const_cast<char *> (s));
 305 }
 306
 307 static inline void
 308 gt_pch_nx (const char *)
 309 {
 310 }
 311
 312 static inline void
 313 gt_ggc_mx (int)
 314 {
 315 }
 316
 317 static inline void
 318 gt_pch_nx (int)
 319 {
 320 }
 321
 322 static inline void
 323 gt_pch_nx (unsigned int)
 324 {
 325 }
 326
 327 #endif