gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  22    an external gc library that might be linked in.  */
  23
  24 /* Constants for general use.  */
  25 extern const char empty_string[];       /* empty string */
  26 extern const char digit_vector[];       /* "0" .. "9" */
  27 #define digit_string(d) (digit_vector + ((d) * 2))
  28
  29 /* Internal functions and data structures used by the GTY
  30    machinery.  */
  31
  32 /* The first parameter is a pointer to a pointer, the second a cookie.  */
  33 typedef void (*gt_pointer_operator) PARAMS ((void *, void *));
  34
  35 #include "gtype-desc.h"
  36
  37 /* One of these applies its third parameter (with cookie in the fourth
  38    parameter) to each pointer in the object pointed to by the first
  39    parameter, using the second parameter.  */
  40 typedef void (*gt_note_pointers)
  41      PARAMS ((void *, void *, gt_pointer_operator, void *));
  42
  43 /* One of these is called before objects are re-ordered in memory.
  44    The first parameter is the original object, the second is the
  45    subobject that has had its pointers reordered, the third parameter
  46    can compute the new values of a pointer when given the cookie in
  47    the fourth parameter.  */
  48 typedef void (*gt_handle_reorder)
  49      PARAMS ((void *, void *, gt_pointer_operator, void *));
  50
  51 /* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
  52 extern int gt_pch_note_object
  53      PARAMS ((void *, void *, gt_note_pointers));
  54
  55 /* Used by the gt_pch_n_* routines.  Register that an object has a reorder
  56    function.  */
  57 extern void gt_pch_note_reorder
  58      PARAMS ((void *, void *, gt_handle_reorder));
  59
  60 /* Mark the object in the first parameter and anything it points to.  */
  61 typedef void (*gt_pointer_walker) PARAMS ((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) PARAMS ((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; non-zero 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                 PARAMS ((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                 PARAMS ((const void *));
 116
 117 /* Mark the entries in the string pool.  */
 118 extern void ggc_mark_stringpool         PARAMS ((void));
 119
 120 /* Call ggc_set_mark on all the roots.  */
 121
 122 extern void ggc_mark_roots              PARAMS ((void));
 123
 124 /* Save and restore the string pool entries for PCH.  */
 125
 126 extern void gt_pch_save_stringpool      PARAMS ((void));
 127 extern void gt_pch_restore_stringpool   PARAMS ((void));
 128
 129 /* PCH and GGC handling for strings, mostly trivial.  */
 130
 131 extern void gt_pch_p_S                  PARAMS ((void *, void *,
 132                                                  gt_pointer_operator, void *));
 133 extern void gt_pch_n_S                  PARAMS ((const void *));
 134 extern void gt_ggc_m_S                  PARAMS ((void *));
 135
 136 /* Initialise the string pool.  */
 137 extern void init_stringpool     PARAMS ((void));
 138
 139 /* A GC implementation must provide these functions.  They are internal
 140    to the GC system.  */
 141
 142 /* Initialize the garbage collector.  */
 143 extern void init_ggc            PARAMS ((void));
 144
 145 /* Start a new GGC context.  Memory allocated in previous contexts
 146    will not be collected while the new context is active.  */
 147 extern void ggc_push_context    PARAMS ((void));
 148
 149 /* Finish a GC context.  Any uncollected memory in the new context
 150    will be merged with the old context.  */
 151 extern void ggc_pop_context     PARAMS ((void));
 152
 153 struct ggc_pch_data;
 154
 155 /* Return a new ggc_pch_data structure.  */
 156 extern struct ggc_pch_data *init_ggc_pch PARAMS ((void));
 157
 158 /* The second parameter and third parameters give the address and size
 159    of an object.  Update the ggc_pch_data structure with as much of
 160    that information as is necessary.  */
 161 extern void ggc_pch_count_object        PARAMS ((struct ggc_pch_data *,
 162                                                  void *, size_t));
 163
 164 /* Return the total size of the data to be written to hold all
 165    the objects previously passed to ggc_pch_count_object.  */
 166 extern size_t ggc_pch_total_size        PARAMS ((struct ggc_pch_data *));
 167
 168 /* The objects, when read, will most likely be at the address
 169    in the second parameter.  */
 170 extern void ggc_pch_this_base           PARAMS ((struct ggc_pch_data *,
 171                                                  void *));
 172
 173 /* Assuming that the objects really do end up at the address
 174    passed to ggc_pch_this_base, return the address of this object.  */
 175 extern char *ggc_pch_alloc_object       PARAMS ((struct ggc_pch_data *,
 176                                                  void *, size_t));
 177
 178 /* Write out any initial information required.  */
 179 extern void ggc_pch_prepare_write       PARAMS ((struct ggc_pch_data *,
 180                                                  FILE *));
 181 /* Write out this object, including any padding.  */
 182 extern void ggc_pch_write_object        PARAMS ((struct ggc_pch_data *,
 183                                                  FILE *, void *, void *,
 184                                                  size_t));
 185 /* All objects have been written, write out any final information
 186    required.  */
 187 extern void ggc_pch_finish              PARAMS ((struct ggc_pch_data *,
 188                                                  FILE *));
 189
 190 /* A PCH file has just been read in at the address specified second
 191    parameter.  Set up the GC implementation for the new objects.  */
 192 extern void ggc_pch_read PARAMS ((FILE *, void *));
 193
 194 \f
 195 /* Allocation.  */
 196
 197 /* The internal primitive.  */
 198 extern void *ggc_alloc          PARAMS ((size_t));
 199 /* Like ggc_alloc, but allocates cleared memory.  */
 200 extern void *ggc_alloc_cleared  PARAMS ((size_t));
 201 /* Resize a block.  */
 202 extern void *ggc_realloc        PARAMS ((void *, size_t));
 203 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 204 extern void *ggc_calloc         PARAMS ((size_t, size_t));
 205
 206 #define ggc_alloc_rtx(NSLOTS)                                             \
 207   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 208                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 209
 210 #define ggc_alloc_rtvec(NELT)                                             \
 211   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 212                                    + ((NELT) - 1) * sizeof (rtx)))
 213
 214 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 215
 216 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 217   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 218
 219 #define splay_tree_new_ggc(COMPARE)                                      \
 220   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 221                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 222                                  NULL)
 223 extern PTR ggc_splay_alloc PARAMS ((int, void *));
 224 extern void ggc_splay_dont_free PARAMS ((void *, void *));
 225
 226 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 227    If LENGTH is -1, then CONTENTS is assumed to be a
 228    null-terminated string and the memory sized accordingly.  */
 229 extern const char *ggc_alloc_string     PARAMS ((const char *contents,
 230                                                  int length));
 231
 232 /* Make a copy of S, in GC-able memory.  */
 233 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 234
 235 /* Invoke the collector.  Garbage collection occurs only when this
 236    function is called, not during allocations.  */
 237 extern void ggc_collect                 PARAMS ((void));
 238
 239 /* Return the number of bytes allocated at the indicated address.  */
 240 extern size_t ggc_get_size              PARAMS ((const void *));
 241
 242 /* Write out all GCed objects to F.  */
 243 extern void gt_pch_save                 PARAMS ((FILE *f));
 244
 245 /* Read objects previously saved with gt_pch_save from F.  */
 246 extern void gt_pch_restore              PARAMS ((FILE *f));
 247 \f
 248 /* Statistics.  */
 249
 250 /* This structure contains the statistics common to all collectors.
 251    Particular collectors can extend this structure.  */
 252 typedef struct ggc_statistics
 253 {
 254   /* At present, we don't really gather any interesting statistics.  */
 255   int unused;
 256 } ggc_statistics;
 257
 258 /* Used by the various collectors to gather and print statistics that
 259    do not depend on the collector in use.  */
 260 extern void ggc_print_common_statistics PARAMS ((FILE *, ggc_statistics *));
 261
 262 /* Print allocation statistics.  */
 263 extern void ggc_print_statistics        PARAMS ((void));
 264 extern void stringpool_statistics       PARAMS ((void));
 265
 266 /* Heuristics.  */
 267 extern int ggc_min_expand_heuristic PARAMS ((void));
 268 extern int ggc_min_heapsize_heuristic PARAMS ((void));
 269 extern void init_ggc_heuristics PARAMS ((void));