gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
   3    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 2, 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 COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  23    an external gc library that might be linked in.  */
  24
  25 /* Constants for general use.  */
  26 extern const char empty_string[];       /* empty string */
  27 extern const char digit_vector[];       /* "0" .. "9" */
  28 #define digit_string(d) (digit_vector + ((d) * 2))
  29
  30 /* Internal functions and data structures used by the GTY
  31    machinery.  */
  32
  33 /* The first parameter is a pointer to a pointer, the second a cookie.  */
  34 typedef void (*gt_pointer_operator) (void *, void *);
  35
  36 #include "gtype-desc.h"
  37
  38 /* One of these applies its third parameter (with cookie in the fourth
  39    parameter) to each pointer in the object pointed to by the first
  40    parameter, using the second parameter.  */
  41 typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
  42                                   void *);
  43
  44 /* One of these is called before objects are re-ordered in memory.
  45    The first parameter is the original object, the second is the
  46    subobject that has had its pointers reordered, the third parameter
  47    can compute the new values of a pointer when given the cookie in
  48    the fourth parameter.  */
  49 typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
  50                                    void *);
  51
  52 /* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
  53 extern int gt_pch_note_object (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 (void *, void *, gt_handle_reorder);
  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_cache_rtab[];
  76 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  77
  78 /* Structure for hash table cache marking.  */
  79 struct htab;
  80 struct ggc_cache_tab {
  81   struct htab * *base;
  82   size_t nelt;
  83   size_t stride;
  84   gt_pointer_walker cb;
  85   gt_pointer_walker pchw;
  86   int (*marked_p) (const void *);
  87 };
  88 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  89 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  90 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  91
  92 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  93    to true.  Otherwise evaluate to false.  */
  94 #define ggc_test_and_set_mark(EXPR) \
  95   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
  96
  97 #define ggc_mark(EXPR)                          \
  98   do {                                          \
  99     const void *const a__ = (EXPR);             \
 100     if (a__ != NULL && a__ != (void *) 1)       \
 101       ggc_set_mark (a__);                       \
 102   } while (0)
 103
 104 /* Actually set the mark on a particular region of memory, but don't
 105    follow pointers.  This function is called by ggc_mark_*.  It
 106    returns zero if the object was not previously marked; nonzero if
 107    the object was already marked, or if, for any other reason,
 108    pointers in this data structure should not be traversed.  */
 109 extern int ggc_set_mark (const void *);
 110
 111 /* Return 1 if P has been marked, zero otherwise.
 112    P must have been allocated by the GC allocator; it mustn't point to
 113    static objects, stack variables, or memory allocated with malloc.  */
 114 extern int ggc_marked_p (const void *);
 115
 116 /* Mark the entries in the string pool.  */
 117 extern void ggc_mark_stringpool (void);
 118
 119 /* Call ggc_set_mark on all the roots.  */
 120
 121 extern void ggc_mark_roots (void);
 122
 123 /* Save and restore the string pool entries for PCH.  */
 124
 125 extern void gt_pch_save_stringpool (void);
 126 extern void gt_pch_fixup_stringpool (void);
 127 extern void gt_pch_restore_stringpool (void);
 128
 129 /* PCH and GGC handling for strings, mostly trivial.  */
 130
 131 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 132 extern void gt_pch_n_S (const void *);
 133 extern void gt_ggc_m_S (void *);
 134
 135 /* Initialise the string pool.  */
 136 extern void init_stringpool (void);
 137
 138 /* A GC implementation must provide these functions.  They are internal
 139    to the GC system.  */
 140
 141 /* Initialize the garbage collector.  */
 142 extern void init_ggc (void);
 143
 144 /* Start a new GGC context.  Memory allocated in previous contexts
 145    will not be collected while the new context is active.  */
 146 extern void ggc_push_context (void);
 147
 148 /* Finish a GC context.  Any uncollected memory in the new context
 149    will be merged with the old context.  */
 150 extern void ggc_pop_context (void);
 151
 152 struct ggc_pch_data;
 153
 154 /* Return a new ggc_pch_data structure.  */
 155 extern struct ggc_pch_data *init_ggc_pch (void);
 156
 157 /* The second parameter and third parameters give the address and size
 158    of an object.  Update the ggc_pch_data structure with as much of
 159    that information as is necessary.  */
 160 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t);
 161
 162 /* Return the total size of the data to be written to hold all
 163    the objects previously passed to ggc_pch_count_object.  */
 164 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 165
 166 /* The objects, when read, will most likely be at the address
 167    in the second parameter.  */
 168 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 169
 170 /* Assuming that the objects really do end up at the address
 171    passed to ggc_pch_this_base, return the address of this object.  */
 172 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t);
 173
 174 /* Write out any initial information required.  */
 175 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 176 /* Write out this object, including any padding.  */
 177 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 178                                   void *, size_t);
 179 /* All objects have been written, write out any final information
 180    required.  */
 181 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 182
 183 /* A PCH file has just been read in at the address specified second
 184    parameter.  Set up the GC implementation for the new objects.  */
 185 extern void ggc_pch_read (FILE *, void *);
 186
 187 \f
 188 /* Allocation.  */
 189
 190 /* The internal primitive.  */
 191 extern void *ggc_alloc (size_t);
 192 /* Like ggc_alloc, but allocates cleared memory.  */
 193 extern void *ggc_alloc_cleared (size_t);
 194 /* Resize a block.  */
 195 extern void *ggc_realloc (void *, size_t);
 196 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 197 extern void *ggc_calloc (size_t, size_t);
 198
 199 #define ggc_alloc_rtx(NSLOTS)                                             \
 200   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 201                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 202
 203 #define ggc_alloc_rtvec(NELT)                                             \
 204   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 205                                    + ((NELT) - 1) * sizeof (rtx)))
 206
 207 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 208
 209 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 210   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 211
 212 #define splay_tree_new_ggc(COMPARE)                                      \
 213   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 214                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 215                                  NULL)
 216 extern void *ggc_splay_alloc (int, void *);
 217 extern void ggc_splay_dont_free (void *, void *);
 218
 219 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 220    If LENGTH is -1, then CONTENTS is assumed to be a
 221    null-terminated string and the memory sized accordingly.  */
 222 extern const char *ggc_alloc_string     PARAMS ((const char *contents,
 223                                                  int length));
 224
 225 /* Make a copy of S, in GC-able memory.  */
 226 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 227
 228 /* Invoke the collector.  Garbage collection occurs only when this
 229    function is called, not during allocations.  */
 230 extern void ggc_collect (void);
 231
 232 /* Return the number of bytes allocated at the indicated address.  */
 233 extern size_t ggc_get_size (const void *);
 234
 235 /* Write out all GCed objects to F.  */
 236 extern void gt_pch_save (FILE *f);
 237
 238 /* Read objects previously saved with gt_pch_save from F.  */
 239 extern void gt_pch_restore (FILE *f);
 240 \f
 241 /* Statistics.  */
 242
 243 /* This structure contains the statistics common to all collectors.
 244    Particular collectors can extend this structure.  */
 245 typedef struct ggc_statistics
 246 {
 247   /* At present, we don't really gather any interesting statistics.  */
 248   int unused;
 249 } ggc_statistics;
 250
 251 /* Used by the various collectors to gather and print statistics that
 252    do not depend on the collector in use.  */
 253 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 254
 255 /* Print allocation statistics.  */
 256 extern void ggc_print_statistics (void);
 257 extern void stringpool_statistics (void);
 258
 259 /* Heuristics.  */
 260 extern int ggc_min_expand_heuristic (void);
 261 extern int ggc_min_heapsize_heuristic (void);
 262 extern void init_ggc_heuristics (void);