gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   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, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22 #ifndef GCC_GGC_H
  23 #define GCC_GGC_H
  24 #include "statistics.h"
  25
  26 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  27    an external gc library that might be linked in.  */
  28
  29 /* Constants for general use.  */
  30 extern const char empty_string[];       /* empty string */
  31 extern const char digit_vector[];       /* "0" .. "9" */
  32 #define digit_string(d) (digit_vector + ((d) * 2))
  33
  34 /* Internal functions and data structures used by the GTY
  35    machinery.  */
  36
  37 /* The first parameter is a pointer to a pointer, the second a cookie.  */
  38 typedef void (*gt_pointer_operator) (void *, void *);
  39
  40 #include "gtype-desc.h"
  41
  42 /* One of these applies its third parameter (with cookie in the fourth
  43    parameter) to each pointer in the object pointed to by the first
  44    parameter, using the second parameter.  */
  45 typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
  46                                   void *);
  47
  48 /* One of these is called before objects are re-ordered in memory.
  49    The first parameter is the original object, the second is the
  50    subobject that has had its pointers reordered, the third parameter
  51    can compute the new values of a pointer when given the cookie in
  52    the fourth parameter.  */
  53 typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
  54                                    void *);
  55
  56 /* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
  57 extern int gt_pch_note_object (void *, void *, gt_note_pointers,
  58                                enum gt_types_enum);
  59
  60 /* Used by the gt_pch_n_* routines.  Register that an object has a reorder
  61    function.  */
  62 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  63
  64 /* Mark the object in the first parameter and anything it points to.  */
  65 typedef void (*gt_pointer_walker) (void *);
  66
  67 /* Structures for the easy way to mark roots.
  68    In an array, terminated by having base == NULL.  */
  69 struct ggc_root_tab {
  70   void *base;
  71   size_t nelt;
  72   size_t stride;
  73   gt_pointer_walker cb;
  74   gt_pointer_walker pchw;
  75 };
  76 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
  77 /* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
  78 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  79 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  80 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  81 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  82
  83 /* Structure for hash table cache marking.  */
  84 struct htab;
  85 struct ggc_cache_tab {
  86   struct htab * *base;
  87   size_t nelt;
  88   size_t stride;
  89   gt_pointer_walker cb;
  90   gt_pointer_walker pchw;
  91   int (*marked_p) (const void *);
  92 };
  93 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  94 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  95 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  96
  97 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  98    to true.  Otherwise evaluate to false.  */
  99 #define ggc_test_and_set_mark(EXPR) \
 100   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
 101
 102 #define ggc_mark(EXPR)                          \
 103   do {                                          \
 104     const void *const a__ = (EXPR);             \
 105     if (a__ != NULL && a__ != (void *) 1)       \
 106       ggc_set_mark (a__);                       \
 107   } while (0)
 108
 109 /* Actually set the mark on a particular region of memory, but don't
 110    follow pointers.  This function is called by ggc_mark_*.  It
 111    returns zero if the object was not previously marked; nonzero if
 112    the object was already marked, or if, for any other reason,
 113    pointers in this data structure should not be traversed.  */
 114 extern int ggc_set_mark (const void *);
 115
 116 /* Return 1 if P has been marked, zero otherwise.
 117    P must have been allocated by the GC allocator; it mustn't point to
 118    static objects, stack variables, or memory allocated with malloc.  */
 119 extern int ggc_marked_p (const void *);
 120
 121 /* Mark the entries in the string pool.  */
 122 extern void ggc_mark_stringpool (void);
 123
 124 /* Call ggc_set_mark on all the roots.  */
 125
 126 extern void ggc_mark_roots (void);
 127
 128 /* Save and restore the string pool entries for PCH.  */
 129
 130 extern void gt_pch_save_stringpool (void);
 131 extern void gt_pch_fixup_stringpool (void);
 132 extern void gt_pch_restore_stringpool (void);
 133
 134 /* PCH and GGC handling for strings, mostly trivial.  */
 135
 136 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 137 extern void gt_pch_n_S (const void *);
 138 extern void gt_ggc_m_S (void *);
 139
 140 /* Initialize the string pool.  */
 141 extern void init_stringpool (void);
 142
 143 /* A GC implementation must provide these functions.  They are internal
 144    to the GC system.  */
 145
 146 /* Forward declare the zone structure.  Only ggc_zone implements this.  */
 147 struct alloc_zone;
 148
 149 /* Initialize the garbage collector.  */
 150 extern void init_ggc (void);
 151
 152 /* Start a new GGC zone.  */
 153 extern struct alloc_zone *new_ggc_zone (const char *);
 154
 155 /* Free a complete GGC zone, destroying everything in it.  */
 156 extern void destroy_ggc_zone (struct alloc_zone *);
 157
 158 struct ggc_pch_data;
 159
 160 /* Return a new ggc_pch_data structure.  */
 161 extern struct ggc_pch_data *init_ggc_pch (void);
 162
 163 /* The second parameter and third parameters give the address and size
 164    of an object.  Update the ggc_pch_data structure with as much of
 165    that information as is necessary. The bool argument should be true
 166    if the object is a string.  */
 167 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool,
 168                                   enum gt_types_enum);
 169
 170 /* Return the total size of the data to be written to hold all
 171    the objects previously passed to ggc_pch_count_object.  */
 172 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 173
 174 /* The objects, when read, will most likely be at the address
 175    in the second parameter.  */
 176 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 177
 178 /* Assuming that the objects really do end up at the address
 179    passed to ggc_pch_this_base, return the address of this object.
 180    The bool argument should be true if the object is a string.  */
 181 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool,
 182                                    enum gt_types_enum);
 183
 184 /* Write out any initial information required.  */
 185 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 186 /* Write out this object, including any padding.  The last argument should be
 187    true if the object is a string.  */
 188 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 189                                   void *, size_t, bool);
 190 /* All objects have been written, write out any final information
 191    required.  */
 192 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 193
 194 /* A PCH file has just been read in at the address specified second
 195    parameter.  Set up the GC implementation for the new objects.  */
 196 extern void ggc_pch_read (FILE *, void *);
 197
 198 \f
 199 /* Allocation.  */
 200
 201 /* When set, ggc_collect will do collection.  */
 202 extern bool ggc_force_collect;
 203
 204 /* The internal primitive.  */
 205 extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
 206 #define ggc_alloc(s) ggc_alloc_stat (s MEM_STAT_INFO)
 207 /* Allocate an object of the specified type and size.  */
 208 extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);
 209 #define ggc_alloc_typed(s,z) ggc_alloc_typed_stat (s,z MEM_STAT_INFO)
 210 /* Like ggc_alloc, but allocates cleared memory.  */
 211 extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
 212 #define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
 213 /* Resize a block.  */
 214 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 215 #define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
 216 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 217 extern void *ggc_calloc (size_t, size_t);
 218 /* Free a block.  To be used when known for certain it's not reachable.  */
 219 extern void ggc_free (void *);
 220
 221 extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
 222 extern void ggc_free_overhead (void *);
 223 extern void ggc_prune_overhead_list (void);
 224
 225 extern void dump_ggc_loc_statistics (void);
 226
 227 /* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
 228 #define GGC_NEW(T)              ((T *) ggc_alloc (sizeof (T)))
 229 #define GGC_CNEW(T)             ((T *) ggc_alloc_cleared (sizeof (T)))
 230 #define GGC_NEWVEC(T, N)        ((T *) ggc_alloc ((N) * sizeof(T)))
 231 #define GGC_CNEWVEC(T, N)       ((T *) ggc_alloc_cleared ((N) * sizeof(T)))
 232 #define GGC_NEWVAR(T, S)        ((T *) ggc_alloc ((S)))
 233 #define GGC_CNEWVAR(T, S)       ((T *) ggc_alloc_cleared ((S)))
 234 #define GGC_RESIZEVEC(T, P, N)  ((T *) ggc_realloc ((P), (N) * sizeof (T)))
 235
 236 #define ggc_alloc_rtvec(NELT)                                            \
 237   ((rtvec) ggc_alloc_zone (sizeof (struct rtvec_def) + ((NELT) - 1)      \
 238                            * sizeof (rtx), &rtl_zone))
 239
 240 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, &tree_zone))
 241
 242 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 243   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 244
 245 #define splay_tree_new_ggc(COMPARE)                                      \
 246   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 247                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 248                                  NULL)
 249 extern void *ggc_splay_alloc (int, void *);
 250 extern void ggc_splay_dont_free (void *, void *);
 251
 252 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 253    If LENGTH is -1, then CONTENTS is assumed to be a
 254    null-terminated string and the memory sized accordingly.  */
 255 extern const char *ggc_alloc_string (const char *contents, int length);
 256
 257 /* Make a copy of S, in GC-able memory.  */
 258 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 259
 260 /* Invoke the collector.  Garbage collection occurs only when this
 261    function is called, not during allocations.  */
 262 extern void ggc_collect (void);
 263
 264 /* Return the number of bytes allocated at the indicated address.  */
 265 extern size_t ggc_get_size (const void *);
 266
 267 /* Write out all GCed objects to F.  */
 268 extern void gt_pch_save (FILE *f);
 269
 270 /* Read objects previously saved with gt_pch_save from F.  */
 271 extern void gt_pch_restore (FILE *f);
 272 \f
 273 /* Statistics.  */
 274
 275 /* This structure contains the statistics common to all collectors.
 276    Particular collectors can extend this structure.  */
 277 typedef struct ggc_statistics
 278 {
 279   /* At present, we don't really gather any interesting statistics.  */
 280   int unused;
 281 } ggc_statistics;
 282
 283 /* Used by the various collectors to gather and print statistics that
 284    do not depend on the collector in use.  */
 285 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 286
 287 /* Print allocation statistics.  */
 288 extern void ggc_print_statistics (void);
 289 extern void stringpool_statistics (void);
 290
 291 /* Heuristics.  */
 292 extern int ggc_min_expand_heuristic (void);
 293 extern int ggc_min_heapsize_heuristic (void);
 294 extern void init_ggc_heuristics (void);
 295
 296 /* Zone collection.  */
 297 #if defined (GGC_ZONE) && !defined (GENERATOR_FILE)
 298
 299 /* For regular rtl allocations.  */
 300 extern struct alloc_zone rtl_zone;
 301 /* For regular tree allocations.  */
 302 extern struct alloc_zone tree_zone;
 303 /* For IDENTIFIER_NODE allocations.  */
 304 extern struct alloc_zone tree_id_zone;
 305
 306 /* Allocate an object into the specified allocation zone.  */
 307 extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
 308 # define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
 309 # define ggc_alloc_zone_pass_stat(s,z) ggc_alloc_zone_stat (s,z PASS_MEM_STAT)
 310 #else
 311
 312 # define ggc_alloc_zone(s, z) ggc_alloc (s)
 313 # define ggc_alloc_zone_pass_stat(s, z) ggc_alloc_stat (s PASS_MEM_STAT)
 314
 315 #endif
 316
 317 #endif