gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004
   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 #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
  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 /* Start a new GGC context.  Memory allocated in previous contexts
 158    will not be collected while the new context is active.  */
 159 extern void ggc_push_context (void);
 160
 161 /* Finish a GC context.  Any uncollected memory in the new context
 162    will be merged with the old context.  */
 163 extern void ggc_pop_context (void);
 164
 165 struct ggc_pch_data;
 166
 167 /* Return a new ggc_pch_data structure.  */
 168 extern struct ggc_pch_data *init_ggc_pch (void);
 169
 170 /* The second parameter and third parameters give the address and size
 171    of an object.  Update the ggc_pch_data structure with as much of
 172    that information as is necessary. The last argument should be true
 173    if the object is a string.  */
 174 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t, bool);
 175
 176 /* Return the total size of the data to be written to hold all
 177    the objects previously passed to ggc_pch_count_object.  */
 178 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 179
 180 /* The objects, when read, will most likely be at the address
 181    in the second parameter.  */
 182 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 183
 184 /* Assuming that the objects really do end up at the address
 185    passed to ggc_pch_this_base, return the address of this object.
 186    The last argument should be true if the object is a string.  */
 187 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t, bool);
 188
 189 /* Write out any initial information required.  */
 190 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 191 /* Write out this object, including any padding.  The last argument should be
 192    true if the object is a string.  */
 193 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 194                                   void *, size_t, bool);
 195 /* All objects have been written, write out any final information
 196    required.  */
 197 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 198
 199 /* A PCH file has just been read in at the address specified second
 200    parameter.  Set up the GC implementation for the new objects.  */
 201 extern void ggc_pch_read (FILE *, void *);
 202
 203 \f
 204 /* Allocation.  */
 205
 206 /* For single pass garbage.  */
 207 extern struct alloc_zone *garbage_zone;
 208 /* For regular rtl allocations.  */
 209 extern struct alloc_zone *rtl_zone;
 210 /* For regular tree allocations.  */
 211 extern struct alloc_zone *tree_zone;
 212 /* When set, ggc_collect will do collection.  */
 213 extern bool ggc_force_collect;
 214
 215 /* The internal primitive.  */
 216 extern void *ggc_alloc_stat (size_t MEM_STAT_DECL);
 217 #define ggc_alloc(s) ggc_alloc_stat (s MEM_STAT_INFO)
 218 /* Allocate an object into the specified allocation zone.  */
 219 extern void *ggc_alloc_zone_stat (size_t, struct alloc_zone * MEM_STAT_DECL);
 220 #define ggc_alloc_zone(s,z) ggc_alloc_zone_stat (s,z MEM_STAT_INFO)
 221 /* Allocate an object of the specified type and size.  */
 222 extern void *ggc_alloc_typed_stat (enum gt_types_enum, size_t MEM_STAT_DECL);
 223 #define ggc_alloc_typed(s,z) ggc_alloc_typed_stat (s,z MEM_STAT_INFO)
 224 /* Like ggc_alloc, but allocates cleared memory.  */
 225 extern void *ggc_alloc_cleared_stat (size_t MEM_STAT_DECL);
 226 #define ggc_alloc_cleared(s) ggc_alloc_cleared_stat (s MEM_STAT_INFO)
 227 /* Like ggc_alloc_zone, but allocates cleared memory.  */
 228 extern void *ggc_alloc_cleared_zone (size_t, struct alloc_zone * MEM_STAT_DECL);
 229 #define ggc_alloc_cleared_zone(s,z) ggc_alloc_cleared_stat (s,z MEM_STAT_INFO)
 230 /* Resize a block.  */
 231 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 232 #define ggc_realloc(s,z) ggc_realloc_stat (s,z MEM_STAT_INFO)
 233 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 234 extern void *ggc_calloc (size_t, size_t);
 235 /* Free a block.  To be used when known for certain it's not reachable.  */
 236 extern void ggc_free (void *);
 237
 238 extern void ggc_record_overhead (size_t, size_t, void * MEM_STAT_DECL);
 239 extern void ggc_free_overhead (void *);
 240 extern void ggc_prune_overhead_list (void);
 241
 242 extern void dump_ggc_loc_statistics (void);
 243
 244 /* Type-safe, C++-friendly versions of ggc_alloc() and gcc_calloc().  */
 245 #define GGC_NEW(T)              ((T *) ggc_alloc (sizeof (T)))
 246 #define GGC_CNEW(T)             ((T *) ggc_alloc_cleared (sizeof (T)))
 247 #define GGC_NEWVEC(T, N)        ((T *) ggc_alloc ((N) * sizeof(T)))
 248 #define GGC_CNEWVEC(T, N)       ((T *) ggc_alloc_cleared ((N) * sizeof(T)))
 249 #define GGC_NEWVAR(T, S)        ((T *) ggc_alloc ((S)))
 250 #define GGC_CNEWVAR(T, S)       ((T *) ggc_alloc_cleared ((S)))
 251
 252 #define ggc_alloc_rtvec(NELT)                                             \
 253   ((rtvec) ggc_alloc_typed (gt_ggc_e_9rtvec_def, sizeof (struct rtvec_def) \
 254                       + ((NELT) - 1) * sizeof (rtx)))
 255
 256 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc_zone (LENGTH, tree_zone))
 257
 258 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 259   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 260
 261 #define splay_tree_new_ggc(COMPARE)                                      \
 262   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 263                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 264                                  NULL)
 265 extern void *ggc_splay_alloc (int, void *);
 266 extern void ggc_splay_dont_free (void *, void *);
 267
 268 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 269    If LENGTH is -1, then CONTENTS is assumed to be a
 270    null-terminated string and the memory sized accordingly.  */
 271 extern const char *ggc_alloc_string (const char *contents, int length);
 272
 273 /* Make a copy of S, in GC-able memory.  */
 274 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 275
 276 /* Invoke the collector.  Garbage collection occurs only when this
 277    function is called, not during allocations.  */
 278 extern void ggc_collect (void);
 279
 280 /* Return the number of bytes allocated at the indicated address.  */
 281 extern size_t ggc_get_size (const void *);
 282
 283 /* Write out all GCed objects to F.  */
 284 extern void gt_pch_save (FILE *f);
 285
 286 /* Read objects previously saved with gt_pch_save from F.  */
 287 extern void gt_pch_restore (FILE *f);
 288 \f
 289 /* Statistics.  */
 290
 291 /* This structure contains the statistics common to all collectors.
 292    Particular collectors can extend this structure.  */
 293 typedef struct ggc_statistics
 294 {
 295   /* At present, we don't really gather any interesting statistics.  */
 296   int unused;
 297 } ggc_statistics;
 298
 299 /* Used by the various collectors to gather and print statistics that
 300    do not depend on the collector in use.  */
 301 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 302
 303 /* Print allocation statistics.  */
 304 extern void ggc_print_statistics (void);
 305 extern void stringpool_statistics (void);
 306
 307 /* Heuristics.  */
 308 extern int ggc_min_expand_heuristic (void);
 309 extern int ggc_min_heapsize_heuristic (void);
 310 extern void init_ggc_heuristics (void);
 311
 312 #endif