gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2
   3    Copyright (C) 1998-2013 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
  31 /* Internal functions and data structures used by the GTY
  32    machinery, including the generated gt*.[hc] files.  */
  33
  34 #include "gtype-desc.h"
  35
  36 /* One of these applies its third parameter (with cookie in the fourth
  37    parameter) to each pointer in the object pointed to by the first
  38    parameter, using the second parameter.  */
  39 typedef void (*gt_note_pointers) (void *, void *, gt_pointer_operator,
  40                                   void *);
  41
  42 /* One of these is called before objects are re-ordered in memory.
  43    The first parameter is the original object, the second is the
  44    subobject that has had its pointers reordered, the third parameter
  45    can compute the new values of a pointer when given the cookie in
  46    the fourth parameter.  */
  47 typedef void (*gt_handle_reorder) (void *, void *, gt_pointer_operator,
  48                                    void *);
  49
  50 /* Used by the gt_pch_n_* routines.  Register an object in the hash table.  */
  51 extern int gt_pch_note_object (void *, void *, gt_note_pointers);
  52
  53 /* Used by the gt_pch_n_* routines.  Register that an object has a reorder
  54    function.  */
  55 extern void gt_pch_note_reorder (void *, void *, gt_handle_reorder);
  56
  57 /* Mark the object in the first parameter and anything it points to.  */
  58 typedef void (*gt_pointer_walker) (void *);
  59
  60 /* Structures for the easy way to mark roots.
  61    In an array, terminated by having base == NULL.  */
  62 struct ggc_root_tab {
  63   void *base;
  64   size_t nelt;
  65   size_t stride;
  66   gt_pointer_walker cb;
  67   gt_pointer_walker pchw;
  68 };
  69 #define LAST_GGC_ROOT_TAB { NULL, 0, 0, NULL, NULL }
  70 /* Pointers to arrays of ggc_root_tab, terminated by NULL.  */
  71 extern const struct ggc_root_tab * const gt_ggc_rtab[];
  72 extern const struct ggc_root_tab * const gt_ggc_deletable_rtab[];
  73 extern const struct ggc_root_tab * const gt_pch_cache_rtab[];
  74 extern const struct ggc_root_tab * const gt_pch_scalar_rtab[];
  75
  76 /* Structure for hash table cache marking.  */
  77 struct htab;
  78 struct ggc_cache_tab {
  79   struct htab * *base;
  80   size_t nelt;
  81   size_t stride;
  82   gt_pointer_walker cb;
  83   gt_pointer_walker pchw;
  84   int (*marked_p) (const void *);
  85 };
  86 #define LAST_GGC_CACHE_TAB { NULL, 0, 0, NULL, NULL, NULL }
  87 /* Pointers to arrays of ggc_cache_tab, terminated by NULL.  */
  88 extern const struct ggc_cache_tab * const gt_ggc_cache_rtab[];
  89
  90 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  91    to true.  Otherwise evaluate to false.  */
  92 #define ggc_test_and_set_mark(EXPR) \
  93   ((EXPR) != NULL && ((void *) (EXPR)) != (void *) 1 && ! ggc_set_mark (EXPR))
  94
  95 #define ggc_mark(EXPR)                          \
  96   do {                                          \
  97     const void *const a__ = (EXPR);             \
  98     if (a__ != NULL && a__ != (void *) 1)       \
  99       ggc_set_mark (a__);                       \
 100   } while (0)
 101
 102 /* Actually set the mark on a particular region of memory, but don't
 103    follow pointers.  This function is called by ggc_mark_*.  It
 104    returns zero if the object was not previously marked; nonzero if
 105    the object was already marked, or if, for any other reason,
 106    pointers in this data structure should not be traversed.  */
 107 extern int ggc_set_mark (const void *);
 108
 109 /* Return 1 if P has been marked, zero otherwise.
 110    P must have been allocated by the GC allocator; it mustn't point to
 111    static objects, stack variables, or memory allocated with malloc.  */
 112 extern int ggc_marked_p (const void *);
 113
 114 /* PCH and GGC handling for strings, mostly trivial.  */
 115 extern void gt_pch_n_S (const void *);
 116 extern void gt_ggc_m_S (const void *);
 117
 118 /* End of GTY machinery API.  */
 119
 120 /* Initialize the string pool.  */
 121 extern void init_stringpool (void);
 122
 123 /* Initialize the garbage collector.  */
 124 extern void init_ggc (void);
 125
 126 /* When true, identifier nodes are considered as GC roots.  When
 127    false, identifier nodes are treated like any other GC-allocated
 128    object, and the identifier hash table is treated as a weak
 129    hash.  */
 130 extern bool ggc_protect_identifiers;
 131
 132 /* Write out all GCed objects to F.  */
 133 extern void gt_pch_save (FILE *f);
 134
 135 \f
 136 /* Allocation.  */
 137
 138 /* The internal primitive.  */
 139 extern void *ggc_internal_alloc_stat (size_t MEM_STAT_DECL)
 140   ATTRIBUTE_MALLOC;
 141
 142 extern size_t ggc_round_alloc_size (size_t requested_size);
 143
 144 #define ggc_internal_alloc(s) ggc_internal_alloc_stat (s MEM_STAT_INFO)
 145
 146 /* Allocates cleared memory.  */
 147 extern void *ggc_internal_cleared_alloc_stat (size_t MEM_STAT_DECL)
 148   ATTRIBUTE_MALLOC;
 149
 150 /* Resize a block.  */
 151 extern void *ggc_realloc_stat (void *, size_t MEM_STAT_DECL);
 152
 153 /* Free a block.  To be used when known for certain it's not reachable.  */
 154 extern void ggc_free (void *);
 155
 156 extern void dump_ggc_loc_statistics (bool);
 157
 158 /* Reallocators.  */
 159 #define GGC_RESIZEVEC(T, P, N) \
 160     ((T *) ggc_realloc_stat ((P), (N) * sizeof (T) MEM_STAT_INFO))
 161
 162 #define GGC_RESIZEVAR(T, P, N)                          \
 163     ((T *) ggc_realloc_stat ((P), (N) MEM_STAT_INFO))
 164
 165 static inline void *
 166 ggc_internal_vec_alloc_stat (size_t s, size_t c MEM_STAT_DECL)
 167 {
 168     return ggc_internal_alloc_stat (c * s PASS_MEM_STAT);
 169 }
 170
 171 static inline void *
 172 ggc_internal_cleared_vec_alloc_stat (size_t s, size_t c MEM_STAT_DECL)
 173 {
 174     return ggc_internal_cleared_alloc_stat (c * s PASS_MEM_STAT);
 175 }
 176
 177 #define ggc_internal_cleared_vec_alloc(s, c) \
 178     (ggc_internal_cleared_vec_alloc_stat ((s), (c) MEM_STAT_INFO))
 179
 180 static inline void *
 181 ggc_alloc_atomic_stat (size_t s MEM_STAT_DECL)
 182 {
 183     return ggc_internal_alloc_stat (s PASS_MEM_STAT);
 184 }
 185
 186 #define ggc_alloc_atomic(S)  (ggc_alloc_atomic_stat ((S) MEM_STAT_INFO))
 187
 188 #define ggc_alloc_cleared_atomic(S)             \
 189     (ggc_internal_cleared_alloc_stat ((S) MEM_STAT_INFO))
 190
 191 extern void *ggc_cleared_alloc_htab_ignore_args (size_t, size_t)
 192   ATTRIBUTE_MALLOC;
 193
 194 extern void *ggc_cleared_alloc_ptr_array_two_args (size_t, size_t)
 195   ATTRIBUTE_MALLOC;
 196
 197 #define htab_create_ggc(SIZE, HASH, EQ, DEL) \
 198   htab_create_typed_alloc (SIZE, HASH, EQ, DEL, \
 199                            ggc_cleared_alloc_htab_ignore_args,          \
 200                            ggc_cleared_alloc_ptr_array_two_args,        \
 201                            ggc_free)
 202
 203 #define splay_tree_new_ggc(COMPARE, ALLOC_TREE, ALLOC_NODE)                  \
 204   splay_tree_new_typed_alloc (COMPARE, NULL, NULL, &ALLOC_TREE, &ALLOC_NODE, \
 205                               &ggc_splay_dont_free, NULL)
 206
 207 extern void *ggc_splay_alloc (int, void *)
 208   ATTRIBUTE_MALLOC;
 209
 210 extern void ggc_splay_dont_free (void *, void *);
 211
 212 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 213    If LENGTH is -1, then CONTENTS is assumed to be a
 214    null-terminated string and the memory sized accordingly.  */
 215 extern const char *ggc_alloc_string_stat (const char *contents, int length
 216                                           MEM_STAT_DECL);
 217
 218 #define ggc_alloc_string(c, l) ggc_alloc_string_stat (c, l MEM_STAT_INFO)
 219
 220 /* Make a copy of S, in GC-able memory.  */
 221 #define ggc_strdup(S) ggc_alloc_string_stat ((S), -1 MEM_STAT_INFO)
 222
 223 /* Invoke the collector.  Garbage collection occurs only when this
 224    function is called, not during allocations.  */
 225 extern void ggc_collect (void);
 226
 227 /* Register an additional root table.  This can be useful for some
 228    plugins.  Does nothing if the passed pointer is NULL. */
 229 extern void ggc_register_root_tab (const struct ggc_root_tab *);
 230
 231 /* Register an additional cache table.  This can be useful for some
 232    plugins.  Does nothing if the passed pointer is NULL. */
 233 extern void ggc_register_cache_tab (const struct ggc_cache_tab *);
 234
 235 /* Read objects previously saved with gt_pch_save from F.  */
 236 extern void gt_pch_restore (FILE *f);
 237 \f
 238 /* Statistics.  */
 239
 240 /* Print allocation statistics.  */
 241 extern void ggc_print_statistics (void);
 242
 243 extern void stringpool_statistics (void);
 244
 245 /* Heuristics.  */
 246 extern void init_ggc_heuristics (void);
 247
 248 #define ggc_alloc_rtvec_sized(NELT)                             \
 249   ggc_alloc_rtvec_def (sizeof (struct rtvec_def)                \
 250                        + ((NELT) - 1) * sizeof (rtx))           \
 251
 252 /* Memory statistics passing versions of some allocators.  Too few of them to
 253    make gengtype produce them, so just define the needed ones here.  */
 254 static inline struct rtx_def *
 255 ggc_alloc_rtx_def_stat (size_t s MEM_STAT_DECL)
 256 {
 257   return (struct rtx_def *) ggc_internal_alloc_stat (s PASS_MEM_STAT);
 258 }
 259
 260 static inline union tree_node *
 261 ggc_alloc_tree_node_stat (size_t s MEM_STAT_DECL)
 262 {
 263   return (union tree_node *) ggc_internal_alloc_stat (s PASS_MEM_STAT);
 264 }
 265
 266 static inline union tree_node *
 267 ggc_alloc_cleared_tree_node_stat (size_t s MEM_STAT_DECL)
 268 {
 269   return (union tree_node *) ggc_internal_cleared_alloc_stat (s PASS_MEM_STAT);
 270 }
 271
 272 static inline union gimple_statement_d *
 273 ggc_alloc_cleared_gimple_statement_d_stat (size_t s MEM_STAT_DECL)
 274 {
 275   return (union gimple_statement_d *)
 276     ggc_internal_cleared_alloc_stat (s PASS_MEM_STAT);
 277 }
 278
 279 #endif