gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
   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 /* Call ggc_set_mark on all the roots.  */
 124
 125 extern void ggc_mark_roots (void);
 126
 127 /* Save and restore the string pool entries for PCH.  */
 128
 129 extern void gt_pch_save_stringpool (void);
 130 extern void gt_pch_fixup_stringpool (void);
 131 extern void gt_pch_restore_stringpool (void);
 132
 133 /* PCH and GGC handling for strings, mostly trivial.  */
 134
 135 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 136 extern void gt_pch_n_S (const void *);
 137 extern void gt_ggc_m_S (void *);
 138
 139 /* Initialize the string pool.  */
 140 extern void init_stringpool (void);
 141
 142 /* A GC implementation must provide these functions.  They are internal
 143    to the GC system.  */
 144
 145 /* Forward declare the zone structure.  Only ggc_zone implements this.  */
 146 struct alloc_zone;
 147
 148 /* Initialize the garbage collector.  */
 149 extern void init_ggc (void);
 150
 151 /* Start a new GGC zone.  */
 152 extern struct alloc_zone *new_ggc_zone (const char *);
 153
 154 /* Free a complete GGC zone, destroying everything in it.  */
 155 extern void destroy_ggc_zone (struct alloc_zone *);
 156
 157 struct ggc_pch_data;
 158
 159 /* Return a new ggc_pch_data structure.  */
 160 extern struct ggc_pch_data *init_ggc_pch (void);
 161
 162 /* The second parameter and third parameters give the address and size
 163    of an object.  Update the ggc_pch_data structure with as much of
 164    that information as is necessary. The bool argument should be true
 165    if the object is a string.  */
 166 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool,
 167                                   enum gt_types_enum);
 168
 169 /* Return the total size of the data to be written to hold all
 170    the objects previously passed to ggc_pch_count_object.  */
 171 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 172
 173 /* The objects, when read, will most likely be at the address
 174    in the second parameter.  */
 175 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 176
 177 /* Assuming that the objects really do end up at the address
 178    passed to ggc_pch_this_base, return the address of this object.
 179    The bool argument should be true if the object is a string.  */
 180 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool,
 181                                    enum gt_types_enum);
 182
 183 /* Write out any initial information required.  */
 184 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 185 /* Write out this object, including any padding.  The last argument should be
 186    true if the object is a string.  */
 187 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 188                                   void *, size_t, bool);
 189 /* All objects have been written, write out any final information
 190    required.  */
 191 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 192
 193 /* A PCH file has just been read in at the address specified second
 194    parameter.  Set up the GC implementation for the new objects.  */
 195 extern void ggc_pch_read (FILE *, void *);
 196
 197 \f
 198 /* Allocation.  */
 199
 200 /* When set, ggc_collect will do collection.  */
 201 extern bool ggc_force_collect;
 202
 203 /* The internal primitive.  */
 204 extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
 205 #define ggc_alloc(s) ggc_alloc_stat (s MEM_STAT_INFO)
 206 /* Allocate an object of the specified type and size.  */
 207 extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);
 208 #define ggc_alloc_typed(s,z) ggc_alloc_typed_stat (s,z MEM_STAT_INFO)
 209 /* Like ggc_alloc, but allocates cleared memory.  */
 210 extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
 211 #define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
 212 /* Resize a block.  */
 213 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 214 #define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
 215 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 216 extern void *ggc_calloc (size_t, size_t);
 217 /* Free a block.  To be used when known for certain it's not reachable.  */
 218 extern void ggc_free (void *);
 219
 220 extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
 221 extern void ggc_free_overhead (void *);
 222 extern void ggc_prune_overhead_list (void);
 223
 224 extern void dump_ggc_loc_statistics (bool);
 225
 226 /* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
 227 #define GGC_NEW(T)              ((T *) ggc_alloc (sizeof (T)))
 228 #define GGC_CNEW(T)             ((T *) ggc_alloc_cleared (sizeof (T)))
 229 #define GGC_NEWVEC(T, N)        ((T *) ggc_alloc ((N) * sizeof(T)))
 230 #define GGC_CNEWVEC(T, N)       ((T *) ggc_alloc_cleared ((N) * sizeof(T)))
 231 #define GGC_NEWVAR(T, S)        ((T *) ggc_alloc ((S)))
 232 #define GGC_CNEWVAR(T, S)       ((T *) ggc_alloc_cleared ((S)))
 233 #define GGC_RESIZEVEC(T, P, N)  ((T *) ggc_realloc ((P), (N) * sizeof (T)))
 234
 235 #define ggc_alloc_rtvec(NELT)                                            \
 236   ((rtvec) ggc_alloc_zone (sizeof (struct rtvec_def) + ((NELT) - 1)      \
 237                            * sizeof (rtx), &rtl_zone))
 238
 239 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, &tree_zone))
 240
 241 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 242   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 243
 244 #define splay_tree_new_ggc(COMPARE)                                      \
 245   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 246                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 247                                  NULL)
 248 extern void *ggc_splay_alloc (int, void *);
 249 extern void ggc_splay_dont_free (void *, void *);
 250
 251 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 252    If LENGTH is -1, then CONTENTS is assumed to be a
 253    null-terminated string and the memory sized accordingly.  */
 254 extern const char *ggc_alloc_string (const char *contents, int length);
 255
 256 /* Make a copy of S, in GC-able memory.  */
 257 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 258
 259 /* Invoke the collector.  Garbage collection occurs only when this
 260    function is called, not during allocations.  */
 261 extern void ggc_collect (void);
 262
 263 /* Return the number of bytes allocated at the indicated address.  */
 264 extern size_t ggc_get_size (const void *);
 265
 266 /* Write out all GCed objects to F.  */
 267 extern void gt_pch_save (FILE *f);
 268
 269 /* Read objects previously saved with gt_pch_save from F.  */
 270 extern void gt_pch_restore (FILE *f);
 271 \f
 272 /* Statistics.  */
 273
 274 /* This structure contains the statistics common to all collectors.
 275    Particular collectors can extend this structure.  */
 276 typedef struct ggc_statistics
 277 {
 278   /* At present, we don't really gather any interesting statistics.  */
 279   int unused;
 280 } ggc_statistics;
 281
 282 /* Used by the various collectors to gather and print statistics that
 283    do not depend on the collector in use.  */
 284 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 285
 286 /* Print allocation statistics.  */
 287 extern void ggc_print_statistics (void);
 288 extern void stringpool_statistics (void);
 289
 290 /* Heuristics.  */
 291 extern int ggc_min_expand_heuristic (void);
 292 extern int ggc_min_heapsize_heuristic (void);
 293 extern void init_ggc_heuristics (void);
 294
 295 /* Zone collection.  */
 296 #if defined (GGC_ZONE) && !defined (GENERATOR_FILE)
 297
 298 /* For regular rtl allocations.  */
 299 extern struct alloc_zone rtl_zone;
 300 /* For regular tree allocations.  */
 301 extern struct alloc_zone tree_zone;
 302 /* For IDENTIFIER_NODE allocations.  */
 303 extern struct alloc_zone tree_id_zone;
 304
 305 /* Allocate an object into the specified allocation zone.  */
 306 extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
 307 # define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
 308 # define ggc_alloc_zone_pass_stat(s,z) ggc_alloc_zone_stat (s,z PASS_MEM_STAT)
 309 #else
 310
 311 # define ggc_alloc_zone(s, z) ggc_alloc (s)
 312 # define ggc_alloc_zone_pass_stat(s, z) ggc_alloc_stat (s PASS_MEM_STAT)
 313
 314 #endif
 315
 316 #endif