gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
   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
  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
  58 /* Used by the gt_pch_n_* routines.  Register that an object has a reorder
  59    function.  */
  60 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  61
  62 /* Mark the object in the first parameter and anything it points to.  */
  63 typedef void (*gt_pointer_walker) (void *);
  64
  65 /* Structures for the easy way to mark roots.
  66    In an array, terminated by having base == NULL.*/
  67 struct ggc_root_tab {
  68   void *base;
  69   size_t nelt;
  70   size_t stride;
  71   gt_pointer_walker cb;
  72   gt_pointer_walker pchw;
  73 };
  74 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
  75 /* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
  76 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  77 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  78 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  79 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  80
  81 /* Structure for hash table cache marking.  */
  82 struct htab;
  83 struct ggc_cache_tab {
  84   struct htab * *base;
  85   size_t nelt;
  86   size_t stride;
  87   gt_pointer_walker cb;
  88   gt_pointer_walker pchw;
  89   int (*marked_p) (const void *);
  90 };
  91 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  92 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  93 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  94
  95 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  96    to true.  Otherwise evaluate to false.  */
  97 #define ggc_test_and_set_mark(EXPR) \
  98   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
  99
 100 #define ggc_mark(EXPR)                          \
 101   do {                                          \
 102     const void *const a__ = (EXPR);             \
 103     if (a__ != NULL && a__ != (void *) 1)       \
 104       ggc_set_mark (a__);                       \
 105   } while (0)
 106
 107 /* Actually set the mark on a particular region of memory, but don't
 108    follow pointers.  This function is called by ggc_mark_*.  It
 109    returns zero if the object was not previously marked; nonzero if
 110    the object was already marked, or if, for any other reason,
 111    pointers in this data structure should not be traversed.  */
 112 extern int ggc_set_mark (const void *);
 113
 114 /* Return 1 if P has been marked, zero otherwise.
 115    P must have been allocated by the GC allocator; it mustn't point to
 116    static objects, stack variables, or memory allocated with malloc.  */
 117 extern int ggc_marked_p (const void *);
 118
 119 /* Mark the entries in the string pool.  */
 120 extern void ggc_mark_stringpool (void);
 121
 122 /* Call ggc_set_mark on all the roots.  */
 123
 124 extern void ggc_mark_roots (void);
 125
 126 /* Save and restore the string pool entries for PCH.  */
 127
 128 extern void gt_pch_save_stringpool (void);
 129 extern void gt_pch_fixup_stringpool (void);
 130 extern void gt_pch_restore_stringpool (void);
 131
 132 /* PCH and GGC handling for strings, mostly trivial.  */
 133
 134 extern void gt_pch_p_S (void *, void *, gt_pointer_operator, void *);
 135 extern void gt_pch_n_S (const void *);
 136 extern void gt_ggc_m_S (void *);
 137
 138 /* Initialize the string pool.  */
 139 extern void init_stringpool (void);
 140
 141 /* A GC implementation must provide these functions.  They are internal
 142    to the GC system.  */
 143
 144 /* Initialize the garbage collector.  */
 145 extern void init_ggc (void);
 146
 147 /* Start a new GGC context.  Memory allocated in previous contexts
 148    will not be collected while the new context is active.  */
 149 extern void ggc_push_context (void);
 150
 151 /* Finish a GC context.  Any uncollected memory in the new context
 152    will be merged with the old context.  */
 153 extern void ggc_pop_context (void);
 154
 155 struct ggc_pch_data;
 156
 157 /* Return a new ggc_pch_data structure.  */
 158 extern struct ggc_pch_data *init_ggc_pch (void);
 159
 160 /* The second parameter and third parameters give the address and size
 161    of an object.  Update the ggc_pch_data structure with as much of
 162    that information as is necessary.  */
 163 extern void ggc_pch_count_object (struct ggc_pch_data *, void *, size_t);
 164
 165 /* Return the total size of the data to be written to hold all
 166    the objects previously passed to ggc_pch_count_object.  */
 167 extern size_t ggc_pch_total_size (struct ggc_pch_data *);
 168
 169 /* The objects, when read, will most likely be at the address
 170    in the second parameter.  */
 171 extern void ggc_pch_this_base (struct ggc_pch_data *, void *);
 172
 173 /* Assuming that the objects really do end up at the address
 174    passed to ggc_pch_this_base, return the address of this object.  */
 175 extern char *ggc_pch_alloc_object (struct ggc_pch_data *, void *, size_t);
 176
 177 /* Write out any initial information required.  */
 178 extern void ggc_pch_prepare_write (struct ggc_pch_data *, FILE *);
 179 /* Write out this object, including any padding.  */
 180 extern void ggc_pch_write_object (struct ggc_pch_data *, FILE *, void *,
 181                                   void *, size_t);
 182 /* All objects have been written, write out any final information
 183    required.  */
 184 extern void ggc_pch_finish (struct ggc_pch_data *, FILE *);
 185
 186 /* A PCH file has just been read in at the address specified second
 187    parameter.  Set up the GC implementation for the new objects.  */
 188 extern void ggc_pch_read (FILE *, void *);
 189
 190 \f
 191 /* Allocation.  */
 192
 193 /* The internal primitive.  */
 194 extern void *ggc_alloc (size_t);
 195 /* Like ggc_alloc, but allocates cleared memory.  */
 196 extern void *ggc_alloc_cleared (size_t);
 197 /* Resize a block.  */
 198 extern void *ggc_realloc (void *, size_t);
 199 /* Like ggc_alloc_cleared, but performs a multiplication.  */
 200 extern void *ggc_calloc (size_t, size_t);
 201
 202 #define ggc_alloc_rtx(NSLOTS)                                             \
 203   ((rtx) ggc_alloc (sizeof (struct rtx_def)                               \
 204                     + ((NSLOTS) - 1) * sizeof (rtunion)))
 205
 206 #define ggc_alloc_rtvec(NELT)                                             \
 207   ((rtvec) ggc_alloc (sizeof (struct rtvec_def)                           \
 208                       + ((NELT) - 1) * sizeof (rtx)))
 209
 210 #define ggc_alloc_tree(LENGTH) ((tree) ggc_alloc (LENGTH))
 211
 212 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 213   htab_create_alloc (SIZE, HASH, EQ, DEL, ggc_calloc, NULL)
 214
 215 #define splay_tree_new_ggc(COMPARE)                                      \
 216   splay_tree_new_with_allocator (COMPARE, NULL, NULL,                    \
 217                                  &ggc_splay_alloc, &ggc_splay_dont_free, \
 218                                  NULL)
 219 extern void *ggc_splay_alloc (int, void *);
 220 extern void ggc_splay_dont_free (void *, void *);
 221
 222 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 223    If LENGTH is -1, then CONTENTS is assumed to be a
 224    null-terminated string and the memory sized accordingly.  */
 225 extern const char *ggc_alloc_string (const char *contents, int length);
 226
 227 /* Make a copy of S, in GC-able memory.  */
 228 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 229
 230 /* Invoke the collector.  Garbage collection occurs only when this
 231    function is called, not during allocations.  */
 232 extern void ggc_collect (void);
 233
 234 /* Return the number of bytes allocated at the indicated address.  */
 235 extern size_t ggc_get_size (const void *);
 236
 237 /* Write out all GCed objects to F.  */
 238 extern void gt_pch_save (FILE *f);
 239
 240 /* Read objects previously saved with gt_pch_save from F.  */
 241 extern void gt_pch_restore (FILE *f);
 242 \f
 243 /* Statistics.  */
 244
 245 /* This structure contains the statistics common to all collectors.
 246    Particular collectors can extend this structure.  */
 247 typedef struct ggc_statistics
 248 {
 249   /* At present, we don't really gather any interesting statistics.  */
 250   int unused;
 251 } ggc_statistics;
 252
 253 /* Used by the various collectors to gather and print statistics that
 254    do not depend on the collector in use.  */
 255 extern void ggc_print_common_statistics (FILE *, ggc_statistics *);
 256
 257 /* Print allocation statistics.  */
 258 extern void ggc_print_statistics (void);
 259 extern void stringpool_statistics (void);
 260
 261 /* Heuristics.  */
 262 extern int ggc_min_expand_heuristic (void);
 263 extern int ggc_min_heapsize_heuristic (void);
 264 extern void init_ggc_heuristics (void);
 265
 266 #endif