gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
   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 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 #include "statistics.h"
  24
  25 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  26    an external gc library that might be linked in.  */
  27
  28 /* Constants for general use.  */
  29 extern const char empty_string[];       /* empty string */
  30 extern const char digit_vector[];       /* "0" .. "9" */
  31 #define digit_string(d) (digit_vector + ((d) * 2))
  32
  33 /* Internal functions and data structures used by the GTY
  34    machinery.  */
  35
  36 /* The first parameter is a pointer to a pointer, the second a cookie.  */
  37 typedef void (*gt_pointer_operator) (void *, void *);
  38
  39 #include "gtype-desc.h"
  40
  41 /* One of these applies its third parameter (with cookie in the fourth
  42    parameter) to each pointer in the object pointed to by the first
  43    parameter, using the second parameter.  */
  44 typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
  45                                   void *);
  46
  47 /* One of these is called before objects are re-ordered in memory.
  48    The first parameter is the original object, the second is the
  49    subobject that has had its pointers reordered, the third parameter
  50    can compute the new values of a pointer when given the cookie in
  51    the fourth parameter.  */
  52 typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
  53                                    void *);
  54
  55 /* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
  56 extern int gt_pch_note_object (void *, void *, gt_note_pointers,
  57                                enum gt_types_enum);
  58
  59 /* Used by the gt_pch_n_* routines.  Register that an object has a reorder
  60    function.  */
  61 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  62
  63 /* Mark the object in the first parameter and anything it points to.  */
  64 typedef void (*gt_pointer_walker) (void *);
  65
  66 /* Structures for the easy way to mark roots.
  67    In an array, terminated by having base == NULL.  */
  68 struct ggc_root_tab {
  69   void *base;
  70   size_t nelt;
  71   size_t stride;
  72   gt_pointer_walker cb;
  73   gt_pointer_walker pchw;
  74 };
  75 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
  76 /* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
  77 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  78 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  79 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  80 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  81
  82 /* Structure for hash table cache marking.  */
  83 struct htab;
  84 struct ggc_cache_tab {
  85   struct htab * *base;
  86   size_t nelt;
  87   size_t stride;
  88   gt_pointer_walker cb;
  89   gt_pointer_walker pchw;
  90   int (*marked_p) (const void *);
  91 };
  92 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  93 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  94 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  95
  96 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  97    to true.  Otherwise evaluate to false.  */
  98 #define ggc_test_and_set_mark(EXPR) \
  99   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
 100
 101 #define ggc_mark(EXPR)                          \
 102   do {                                          \
 103     const void *const a__ = (EXPR);             \
 104     if (a__ != NULL && a__ != (void *) 1)       \
 105       ggc_set_mark (a__);                       \
 106   } while (0)
 107
 108 /* Actually set the mark on a particular region of memory, but don't
 109    follow pointers.  This function is called by ggc_mark_*.  It
 110    returns zero if the object was not previously marked; nonzero if
 111    the object was already marked, or if, for any other reason,
 112    pointers in this data structure should not be traversed.  */
 113 extern int ggc_set_mark (const void *);
 114
 115 /* Return 1 if P has been marked, zero otherwise.
 116    P must have been allocated by the GC allocator; it mustn't point to
 117    static objects, stack variables, or memory allocated with malloc.  */
 118 extern int ggc_marked_p (const void *);
 119
 120 /* Mark the entries in the string pool.  */
 121 extern void ggc_mark_stringpool (void);
 122
 123 /* Purge the entries in the string pool.  */
 124 extern void ggc_purge_stringpool (void);
 125
 126 /* Call ggc_set_mark on all the roots.  */
 127
 128 extern void ggc_mark_roots (void);
 129
 130 /* Save and restore the string pool entries for PCH.  */
 131
 132 extern void gt_pch_save_stringpool (void);
 133 extern void gt_pch_fixup_stringpool (void);
 134 extern void gt_pch_restore_stringpool (void);
 135
 136 /* PCH and GGC handling for strings, mostly trivial.  */
 137
 138 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 139 extern void gt_pch_n_S (const void *);
 140 extern void gt_ggc_m_S (const void *);
 141
 142 /* Initialize the string pool.  */
 143 extern void init_stringpool (void);
 144
 145 /* A GC implementation must provide these functions.  They are internal
 146    to the GC system.  */
 147
 148 /* Forward declare the zone structure.  Only ggc_zone implements this.  */
 149 struct alloc_zone;
 150
 151 /* Initialize the garbage collector.  */
 152 extern void init_ggc (void);
 153
 154 /* Start a new GGC zone.  */
 155 extern struct alloc_zone *new_ggc_zone (const char *);
 156
 157 /* Free a complete GGC zone, destroying everything in it.  */
 158 extern void destroy_ggc_zone (struct alloc_zone *);
 159
 160 struct ggc_pch_data;
 161
 162 /* Return a new ggc_pch_data structure.  */
 163 extern struct ggc_pch_data *init_ggc_pch (void);
 164
 165 /* The second parameter and third parameters give the address and size
 166    of an object.  Update the ggc_pch_data structure with as much of
 167    that information as is necessary. The bool argument should be true
 168    if the object is a string.  */
 169 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool,
 170                                   enum gt_types_enum);
 171
 172 /* Return the total size of the data to be written to hold all
 173    the objects previously passed to ggc_pch_count_object.  */
 174 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 175
 176 /* The objects, when read, will most likely be at the address
 177    in the second parameter.  */
 178 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 179
 180 /* Assuming that the objects really do end up at the address
 181    passed to ggc_pch_this_base, return the address of this object.
 182    The bool argument should be true if the object is a string.  */
 183 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool,
 184                                    enum gt_types_enum);
 185
 186 /* Write out any initial information required.  */
 187 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 188 /* Write out this object, including any padding.  The last argument should be
 189    true if the object is a string.  */
 190 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 191                                   void *, size_t, bool);
 192 /* All objects have been written, write out any final information
 193    required.  */
 194 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 195
 196 /* A PCH file has just been read in at the address specified second
 197    parameter.  Set up the GC implementation for the new objects.  */
 198 extern void ggc_pch_read (FILE *, void *);
 199
 200 \f
 201 /* Allocation.  */
 202
 203 /* When set, ggc_collect will do collection.  */
 204 extern bool ggc_force_collect;
 205
 206 /* When true, identifier nodes are considered as GC roots.  When
 207    false, identifier nodes are treated like any other GC-allocated
 208    object, and the identifier hash table is treated as a weak
 209    hash.  */
 210 extern bool ggc_protect_identifiers;
 211
 212 /* The internal primitive.  */
 213 extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
 214 #define ggc_alloc(s) ggc_alloc_stat (s MEM_STAT_INFO)
 215 /* Allocate an object of the specified type and size.  */
 216 extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);
 217 #define ggc_alloc_typed(s,z) ggc_alloc_typed_stat (s,z MEM_STAT_INFO)
 218 /* Like ggc_alloc, but allocates cleared memory.  */
 219 extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
 220 #define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
 221 /* Resize a block.  */
 222 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 223 #define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
 224 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 225 extern void *ggc_calloc (size_t, size_t);
 226 /* Free a block.  To be used when known for certain it's not reachable.  */
 227 extern void ggc_free (void *);
 228
 229 extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
 230 extern void ggc_free_overhead (void *);
 231 extern void ggc_prune_overhead_list (void);
 232
 233 extern void dump_ggc_loc_statistics (bool);
 234
 235 /* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
 236 #define GGC_NEW(T)              ((T *) ggc_alloc (sizeof (T)))
 237 #define GGC_CNEW(T)             ((T *) ggc_alloc_cleared (sizeof (T)))
 238 #define GGC_NEWVEC(T, N)        ((T *) ggc_alloc ((N) * sizeof(T)))
 239 #define GGC_CNEWVEC(T, N)       ((T *) ggc_alloc_cleared ((N) * sizeof(T)))
 240 #define GGC_NEWVAR(T, S)        ((T *) ggc_alloc ((S)))
 241 #define GGC_CNEWVAR(T, S)       ((T *) ggc_alloc_cleared ((S)))
 242 #define GGC_RESIZEVEC(T, P, N)  ((T *) ggc_realloc ((P), (N) * sizeof (T)))
 243
 244 #define ggc_alloc_rtvec(NELT)                                            \
 245   ((rtvec) ggc_alloc_zone (sizeof (struct rtvec_def) + ((NELT) - 1)      \
 246                            * sizeof (rtx), &rtl_zone))
 247
 248 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, &tree_zone))
 249
 250 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 251   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 252
 253 #define splay_tree_new_ggc(COMPARE)                                      \
 254   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 255                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 256                                  NULL)
 257 extern void *ggc_splay_alloc (int, void *);
 258 extern void ggc_splay_dont_free (void *, void *);
 259
 260 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 261    If LENGTH is -1, then CONTENTS is assumed to be a
 262    null-terminated string and the memory sized accordingly.  */
 263 extern const char *ggc_alloc_string (const char *contents, int length);
 264
 265 /* Make a copy of S, in GC-able memory.  */
 266 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 267
 268 /* Invoke the collector.  Garbage collection occurs only when this
 269    function is called, not during allocations.  */
 270 extern void ggc_collect (void);
 271
 272 /* Return the number of bytes allocated at the indicated address.  */
 273 extern size_t ggc_get_size (const void *);
 274
 275 /* Write out all GCed objects to F.  */
 276 extern void gt_pch_save (FILE *f);
 277
 278 /* Read objects previously saved with gt_pch_save from F.  */
 279 extern void gt_pch_restore (FILE *f);
 280 \f
 281 /* Statistics.  */
 282
 283 /* This structure contains the statistics common to all collectors.
 284    Particular collectors can extend this structure.  */
 285 typedef struct ggc_statistics
 286 {
 287   /* At present, we don't really gather any interesting statistics.  */
 288   int unused;
 289 } ggc_statistics;
 290
 291 /* Used by the various collectors to gather and print statistics that
 292    do not depend on the collector in use.  */
 293 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 294
 295 /* Print allocation statistics.  */
 296 extern void ggc_print_statistics (void);
 297 extern void stringpool_statistics (void);
 298
 299 /* Heuristics.  */
 300 extern int ggc_min_expand_heuristic (void);
 301 extern int ggc_min_heapsize_heuristic (void);
 302 extern void init_ggc_heuristics (void);
 303
 304 /* Zone collection.  */
 305 #if defined (GGC_ZONE) && !defined (GENERATOR_FILE)
 306
 307 /* For regular rtl allocations.  */
 308 extern struct alloc_zone rtl_zone;
 309 /* For regular tree allocations.  */
 310 extern struct alloc_zone tree_zone;
 311 /* For IDENTIFIER_NODE allocations.  */
 312 extern struct alloc_zone tree_id_zone;
 313
 314 /* Allocate an object into the specified allocation zone.  */
 315 extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
 316 # define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
 317 # define ggc_alloc_zone_pass_stat(s,z) ggc_alloc_zone_stat (s,z PASS_MEM_STAT)
 318 #else
 319
 320 # define ggc_alloc_zone(s, z) ggc_alloc (s)
 321 # define ggc_alloc_zone_pass_stat(s, z) ggc_alloc_stat (s PASS_MEM_STAT)
 322
 323 #endif
 324
 325 #endif