gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2
   3    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007,
   4    2008, 2009 Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  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 /* Purge the entries in the string pool.  */
 125 extern void ggc_purge_stringpool (void);
 126
 127 /* Call ggc_set_mark on all the roots.  */
 128
 129 extern void ggc_mark_roots (void);
 130
 131 /* Save and restore the string pool entries for PCH.  */
 132
 133 extern void gt_pch_save_stringpool (void);
 134 extern void gt_pch_fixup_stringpool (void);
 135 extern void gt_pch_restore_stringpool (void);
 136
 137 /* PCH and GGC handling for strings, mostly trivial.  */
 138
 139 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 140 extern void gt_pch_n_S (const void *);
 141 extern void gt_ggc_m_S (const void *);
 142
 143 /* Initialize the string pool.  */
 144 extern void init_stringpool (void);
 145
 146 /* A GC implementation must provide these functions.  They are internal
 147    to the GC system.  */
 148
 149 /* Forward declare the zone structure.  Only ggc_zone implements this.  */
 150 struct alloc_zone;
 151
 152 /* Initialize the garbage collector.  */
 153 extern void init_ggc (void);
 154
 155 /* Start a new GGC zone.  */
 156 extern struct alloc_zone *new_ggc_zone (const char *);
 157
 158 /* Free a complete GGC zone, destroying everything in it.  */
 159 extern void destroy_ggc_zone (struct alloc_zone *);
 160
 161 struct ggc_pch_data;
 162
 163 /* Return a new ggc_pch_data structure.  */
 164 extern struct ggc_pch_data *init_ggc_pch (void);
 165
 166 /* The second parameter and third parameters give the address and size
 167    of an object.  Update the ggc_pch_data structure with as much of
 168    that information as is necessary. The bool argument should be true
 169    if the object is a string.  */
 170 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool,
 171                                   enum gt_types_enum);
 172
 173 /* Return the total size of the data to be written to hold all
 174    the objects previously passed to ggc_pch_count_object.  */
 175 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 176
 177 /* The objects, when read, will most likely be at the address
 178    in the second parameter.  */
 179 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 180
 181 /* Assuming that the objects really do end up at the address
 182    passed to ggc_pch_this_base, return the address of this object.
 183    The bool argument should be true if the object is a string.  */
 184 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool,
 185                                    enum gt_types_enum);
 186
 187 /* Write out any initial information required.  */
 188 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 189 /* Write out this object, including any padding.  The last argument should be
 190    true if the object is a string.  */
 191 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 192                                   void *, size_t, bool);
 193 /* All objects have been written, write out any final information
 194    required.  */
 195 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 196
 197 /* A PCH file has just been read in at the address specified second
 198    parameter.  Set up the GC implementation for the new objects.  */
 199 extern void ggc_pch_read (FILE *, void *);
 200
 201 \f
 202 /* Allocation.  */
 203
 204 /* When set, ggc_collect will do collection.  */
 205 extern bool ggc_force_collect;
 206
 207 /* When true, identifier nodes are considered as GC roots.  When
 208    false, identifier nodes are treated like any other GC-allocated
 209    object, and the identifier hash table is treated as a weak
 210    hash.  */
 211 extern bool ggc_protect_identifiers;
 212
 213 /* The internal primitive.  */
 214 extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
 215 #define ggc_alloc(s) ggc_alloc_stat (s MEM_STAT_INFO)
 216 /* Allocate an object of the specified type and size.  */
 217 extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);
 218 #define ggc_alloc_typed(s,z) ggc_alloc_typed_stat (s,z MEM_STAT_INFO)
 219 /* Like ggc_alloc, but allocates cleared memory.  */
 220 extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
 221 #define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
 222 /* Resize a block.  */
 223 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 224 #define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
 225 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 226 extern void *ggc_calloc (size_t, size_t);
 227 /* Free a block.  To be used when known for certain it's not reachable.  */
 228 extern void ggc_free (void *);
 229
 230 extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
 231 extern void ggc_free_overhead (void *);
 232 extern void ggc_prune_overhead_list (void);
 233
 234 extern void dump_ggc_loc_statistics (bool);
 235
 236 /* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
 237 #define GGC_NEW(T)              ((T *) ggc_alloc (sizeof (T)))
 238 #define GGC_CNEW(T)             ((T *) ggc_alloc_cleared (sizeof (T)))
 239 #define GGC_NEWVEC(T, N)        ((T *) ggc_alloc ((N) * sizeof(T)))
 240 #define GGC_CNEWVEC(T, N)       ((T *) ggc_alloc_cleared ((N) * sizeof(T)))
 241 #define GGC_RESIZEVEC(T, P, N)  ((T *) ggc_realloc ((P), (N) * sizeof (T)))
 242 #define GGC_NEWVAR(T, S)        ((T *) ggc_alloc ((S)))
 243 #define GGC_CNEWVAR(T, S)       ((T *) ggc_alloc_cleared ((S)))
 244 #define GGC_RESIZEVAR(T, P, N)  ((T *) ggc_realloc ((P), (N)))
 245
 246 #define ggc_alloc_rtvec(NELT)                                            \
 247   ((rtvec) ggc_alloc_zone (sizeof (struct rtvec_def) + ((NELT) - 1)      \
 248                            * sizeof (rtx), &rtl_zone))
 249
 250 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, &tree_zone))
 251
 252 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 253   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, ggc_free)
 254
 255 #define splay_tree_new_ggc(COMPARE)                                      \
 256   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 257                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 258                                  NULL)
 259 extern void *ggc_splay_alloc (int, void *);
 260 extern void ggc_splay_dont_free (void *, void *);
 261
 262 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 263    If LENGTH is -1, then CONTENTS is assumed to be a
 264    null-terminated string and the memory sized accordingly.  */
 265 extern const char *ggc_alloc_string (const char *contents, int length);
 266
 267 /* Make a copy of S, in GC-able memory.  */
 268 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 269
 270 /* Invoke the collector.  Garbage collection occurs only when this
 271    function is called, not during allocations.  */
 272 extern void ggc_collect (void);
 273
 274 /* Register an additional root table.  This can be useful for some
 275    plugins.  Does nothing if the passed pointer is NULL. */
 276 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 277
 278 /* Register an additional cache table.  This can be useful for some
 279    plugins.  Does nothing if the passed pointer is NULL. */
 280 extern void ggc_register_cache_tab (const struct ggc_cache_tab *);
 281
 282 /* Return the number of bytes allocated at the indicated address.  */
 283 extern size_t ggc_get_size (const void *);
 284
 285 /* Write out all GCed objects to F.  */
 286 extern void gt_pch_save (FILE *f);
 287
 288 /* Read objects previously saved with gt_pch_save from F.  */
 289 extern void gt_pch_restore (FILE *f);
 290 \f
 291 /* Statistics.  */
 292
 293 /* This structure contains the statistics common to all collectors.
 294    Particular collectors can extend this structure.  */
 295 typedef struct ggc_statistics
 296 {
 297   /* At present, we don't really gather any interesting statistics.  */
 298   int unused;
 299 } ggc_statistics;
 300
 301 /* Used by the various collectors to gather and print statistics that
 302    do not depend on the collector in use.  */
 303 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 304
 305 /* Print allocation statistics.  */
 306 extern void ggc_print_statistics (void);
 307 extern void stringpool_statistics (void);
 308
 309 /* Heuristics.  */
 310 extern int ggc_min_expand_heuristic (void);
 311 extern int ggc_min_heapsize_heuristic (void);
 312 extern void init_ggc_heuristics (void);
 313
 314 /* Zone collection.  */
 315 #if defined (GGC_ZONE) && !defined (GENERATOR_FILE)
 316
 317 /* For regular rtl allocations.  */
 318 extern struct alloc_zone rtl_zone;
 319 /* For regular tree allocations.  */
 320 extern struct alloc_zone tree_zone;
 321 /* For IDENTIFIER_NODE allocations.  */
 322 extern struct alloc_zone tree_id_zone;
 323
 324 /* Allocate an object into the specified allocation zone.  */
 325 extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
 326 # define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
 327 # define ggc_alloc_zone_pass_stat(s,z) ggc_alloc_zone_stat (s,z PASS_MEM_STAT)
 328 #else
 329
 330 # define ggc_alloc_zone(s, z) ggc_alloc (s)
 331 # define ggc_alloc_zone_pass_stat(s, z) ggc_alloc_stat (s PASS_MEM_STAT)
 332
 333 #endif
 334
 335 #endif