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_fixup_stringpool     PARAMS ((void));
 128 extern void gt_pch_restore_stringpool   PARAMS ((void));
 129
 130 /* PCH and GGC handling for strings, mostly trivial.  */
 131
 132 extern void gt_pch_p_S                  PARAMS ((void *, void *,
 133                                                  gt_pointer_operator, void *));
 134 extern void gt_pch_n_S                  PARAMS ((const void *));
 135 extern void gt_ggc_m_S                  PARAMS ((void *));
 136
 137 /* Initialise the string pool.  */
 138 extern void init_stringpool     PARAMS ((void));
 139
 140 /* A GC implementation must provide these functions.  They are internal
 141    to the GC system.  */
 142
 143 /* Initialize the garbage collector.  */
 144 extern void init_ggc            PARAMS ((void));
 145
 146 /* Start a new GGC context.  Memory allocated in previous contexts
 147    will not be collected while the new context is active.  */
 148 extern void ggc_push_context    PARAMS ((void));
 149
 150 /* Finish a GC context.  Any uncollected memory in the new context
 151    will be merged with the old context.  */
 152 extern void ggc_pop_context     PARAMS ((void));
 153
 154 struct ggc_pch_data;
 155
 156 /* Return a new ggc_pch_data structure.  */
 157 extern struct ggc_pch_data *init_ggc_pch PARAMS ((void));
 158
 159 /* The second parameter and third parameters give the address and size
 160    of an object.  Update the ggc_pch_data structure with as much of
 161    that information as is necessary.  */
 162 extern void ggc_pch_count_object        PARAMS ((struct ggc_pch_data *,
 163                                                  void *, size_t));
 164
 165 /* Return the total size of the data to be written to hold all
 166    the objects previously passed to ggc_pch_count_object.  */
 167 extern size_t ggc_pch_total_size        PARAMS ((struct ggc_pch_data *));
 168
 169 /* The objects, when read, will most likely be at the address
 170    in the second parameter.  */
 171 extern void ggc_pch_this_base           PARAMS ((struct ggc_pch_data *,
 172                                                  void *));
 173
 174 /* Assuming that the objects really do end up at the address
 175    passed to ggc_pch_this_base, return the address of this object.  */
 176 extern char *ggc_pch_alloc_object       PARAMS ((struct ggc_pch_data *,
 177                                                  void *, size_t));
 178
 179 /* Write out any initial information required.  */
 180 extern void ggc_pch_prepare_write       PARAMS ((struct ggc_pch_data *,
 181                                                  FILE *));
 182 /* Write out this object, including any padding.  */
 183 extern void ggc_pch_write_object        PARAMS ((struct ggc_pch_data *,
 184                                                  FILE *, void *, void *,
 185                                                  size_t));
 186 /* All objects have been written, write out any final information
 187    required.  */
 188 extern void ggc_pch_finish              PARAMS ((struct ggc_pch_data *,
 189                                                  FILE *));
 190
 191 /* A PCH file has just been read in at the address specified second
 192    parameter.  Set up the GC implementation for the new objects.  */
 193 extern void ggc_pch_read PARAMS ((FILE *, void *));
 194
 195 \f
 196 /* Allocation.  */
 197
 198 /* The internal primitive.  */
 199 extern void *ggc_alloc          PARAMS ((size_t));
 200 /* Like ggc_alloc, but allocates cleared memory.  */
 201 extern void *ggc_alloc_cleared  PARAMS ((size_t));
 202 /* Resize a block.  */
 203 extern void *ggc_realloc        PARAMS ((void *, size_t));
 204 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 205 extern void *ggc_calloc         PARAMS ((size_t, size_t));
 206
 207 #define ggc_alloc_rtx(NSLOTS)                                             \
 208   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 209                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 210
 211 #define ggc_alloc_rtvec(NELT)                                             \
 212   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 213                                    + ((NELT) - 1) * sizeof (rtx)))
 214
 215 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 216
 217 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 218   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 219
 220 #define splay_tree_new_ggc(COMPARE)                                      \
 221   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 222                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 223                                  NULL)
 224 extern PTR ggc_splay_alloc PARAMS ((int, void *));
 225 extern void ggc_splay_dont_free PARAMS ((void *, void *));
 226
 227 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 228    If LENGTH is -1, then CONTENTS is assumed to be a
 229    null-terminated string and the memory sized accordingly.  */
 230 extern const char *ggc_alloc_string     PARAMS ((const char *contents,
 231                                                  int length));
 232
 233 /* Make a copy of S, in GC-able memory.  */
 234 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 235
 236 /* Invoke the collector.  Garbage collection occurs only when this
 237    function is called, not during allocations.  */
 238 extern void ggc_collect                 PARAMS ((void));
 239
 240 /* Return the number of bytes allocated at the indicated address.  */
 241 extern size_t ggc_get_size              PARAMS ((const void *));
 242
 243 /* Write out all GCed objects to F.  */
 244 extern void gt_pch_save                 PARAMS ((FILE *f));
 245
 246 /* Read objects previously saved with gt_pch_save from F.  */
 247 extern void gt_pch_restore              PARAMS ((FILE *f));
 248 \f
 249 /* Statistics.  */
 250
 251 /* This structure contains the statistics common to all collectors.
 252    Particular collectors can extend this structure.  */
 253 typedef struct ggc_statistics
 254 {
 255   /* At present, we don't really gather any interesting statistics.  */
 256   int unused;
 257 } ggc_statistics;
 258
 259 /* Used by the various collectors to gather and print statistics that
 260    do not depend on the collector in use.  */
 261 extern void ggc_print_common_statistics PARAMS ((FILE *, ggc_statistics *));
 262
 263 /* Print allocation statistics.  */
 264 extern void ggc_print_statistics        PARAMS ((void));
 265 extern void stringpool_statistics       PARAMS ((void));
 266
 267 /* Heuristics.  */
 268 extern int ggc_min_expand_heuristic PARAMS ((void));
 269 extern int ggc_min_heapsize_heuristic PARAMS ((void));
 270 extern void init_ggc_heuristics PARAMS ((void));