gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #include "varray.h"
  22
  23 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  24    an external gc library that might be linked in.  */
  25
  26 /* These structures are defined in various headers throughout the
  27    compiler.  However, rather than force everyone who includes this
  28    header to include all the headers in which they are declared, we
  29    just forward-declare them here.  */
  30 struct eh_status;
  31 struct emit_status;
  32 struct expr_status;
  33 struct hash_table;
  34 struct label_node;
  35 struct rtx_def;
  36 struct rtvec_def;
  37 struct stmt_status;
  38 union  tree_node;
  39 struct varasm_status;
  40
  41 /* Constants for general use.  */
  42 extern const char empty_string[];       /* empty string */
  43 extern const char digit_vector[];       /* "0" .. "9" */
  44 #define digit_string(d) (digit_vector + ((d) * 2))
  45
  46 /* Trees that have been marked, but whose children still need marking.  */
  47 extern varray_type ggc_pending_trees;
  48
  49 /* Manipulate global roots that are needed between calls to gc.  */
  50 extern void ggc_add_root                PARAMS ((void *base, int nelt,
  51                                                  int size, void (*)(void *)));
  52 extern void ggc_add_rtx_root            PARAMS ((struct rtx_def **, int nelt));
  53 extern void ggc_add_tree_root           PARAMS ((union tree_node **,
  54                                                  int nelt));
  55 extern void ggc_add_rtx_varray_root     PARAMS ((struct varray_head_tag **,
  56                                                  int nelt));
  57 extern void ggc_add_tree_varray_root    PARAMS ((struct varray_head_tag **,
  58                                                  int nelt));
  59 extern void ggc_add_tree_hash_table_root PARAMS ((struct hash_table **,
  60                                                   int nelt));
  61 extern void ggc_del_root                PARAMS ((void *base));
  62
  63 /* Types used for mark test and marking functions, if specified, in call
  64    below.  */
  65 typedef int (*ggc_htab_marked_p) PARAMS ((const void *));
  66 typedef void (*ggc_htab_mark) PARAMS ((const void *));
  67
  68 /* Add a hash table to be scanned when all roots have been processed.  We
  69    delete any entry in the table that has not been marked.  The argument is
  70    really htab_t.  */
  71 extern void ggc_add_deletable_htab      PARAMS ((PTR, ggc_htab_marked_p,
  72                                                  ggc_htab_mark));
  73
  74 /* Mark nodes from the gc_add_root callback.  These functions follow
  75    pointers to mark other objects too.  */
  76 extern void ggc_mark_rtx_varray         PARAMS ((struct varray_head_tag *));
  77 extern void ggc_mark_tree_varray        PARAMS ((struct varray_head_tag *));
  78 extern void ggc_mark_tree_hash_table    PARAMS ((struct hash_table *));
  79 extern void ggc_mark_roots              PARAMS ((void));
  80
  81 extern void ggc_mark_rtx_children       PARAMS ((struct rtx_def *));
  82 extern void ggc_mark_rtvec_children     PARAMS ((struct rtvec_def *));
  83
  84 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  85    to true.  Otherwise evaluate to false.  */
  86 #define ggc_test_and_set_mark(EXPR) \
  87   ((EXPR) != NULL && ! ggc_set_mark (EXPR))
  88
  89 #define ggc_mark_rtx(EXPR)                      \
  90   do {                                          \
  91     rtx r__ = (EXPR);                           \
  92     if (ggc_test_and_set_mark (r__))            \
  93       ggc_mark_rtx_children (r__);              \
  94   } while (0)
  95
  96 #define ggc_mark_tree(EXPR)                             \
  97   do {                                                  \
  98     tree t__ = (EXPR);                                  \
  99     if (ggc_test_and_set_mark (t__))                    \
 100       VARRAY_PUSH_TREE (ggc_pending_trees, t__);        \
 101   } while (0)
 102
 103 #define ggc_mark_nonnull_tree(EXPR)                     \
 104   do {                                                  \
 105     tree t__ = (EXPR);                                  \
 106     if (! ggc_set_mark (t__))                           \
 107       VARRAY_PUSH_TREE (ggc_pending_trees, t__);        \
 108   } while (0)
 109
 110 #define ggc_mark_rtvec(EXPR)                    \
 111   do {                                          \
 112     rtvec v__ = (EXPR);                         \
 113     if (ggc_test_and_set_mark (v__))            \
 114       ggc_mark_rtvec_children (v__);            \
 115   } while (0)
 116
 117 #define ggc_mark(EXPR)                          \
 118   do {                                          \
 119     const void *a__ = (EXPR);                   \
 120     if (a__ != NULL)                            \
 121       ggc_set_mark (a__);                       \
 122   } while (0)
 123
 124 /* A GC implementation must provide these functions.  */
 125
 126 /* Initialize the garbage collector.   */
 127 extern void init_ggc            PARAMS ((void));
 128 extern void init_stringpool     PARAMS ((void));
 129
 130 /* Start a new GGC context.  Memory allocated in previous contexts
 131    will not be collected while the new context is active.  */
 132 extern void ggc_push_context    PARAMS ((void));
 133
 134 /* Finish a GC context.  Any uncollected memory in the new context
 135    will be merged with the old context.  */
 136 extern void ggc_pop_context     PARAMS ((void));
 137
 138 /* Allocation.  */
 139
 140 /* The internal primitive.  */
 141 extern void *ggc_alloc          PARAMS ((size_t));
 142 /* Like ggc_alloc, but allocates cleared memory.  */
 143 extern void *ggc_alloc_cleared  PARAMS ((size_t));
 144
 145 #define ggc_alloc_rtx(NSLOTS)                                             \
 146   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 147                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 148
 149 #define ggc_alloc_rtvec(NELT)                                             \
 150   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 151                                    + ((NELT) - 1) * sizeof (rtx)))
 152
 153 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 154
 155 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 156    If LENGTH is -1, then CONTENTS is assumed to be a
 157    null-terminated string and the memory sized accordingly.  */
 158 extern const char *ggc_alloc_string     PARAMS ((const char *contents,
 159                                                  int length));
 160
 161 /* Make a copy of S, in GC-able memory.  */
 162 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 163
 164 /* Invoke the collector.  Garbage collection occurs only when this
 165    function is called, not during allocations.  */
 166 extern void ggc_collect                 PARAMS ((void));
 167
 168 /* Actually set the mark on a particular region of memory, but don't
 169    follow pointers.  This function is called by ggc_mark_*.  It
 170    returns zero if the object was not previously marked; non-zero if
 171    the object was already marked, or if, for any other reason,
 172    pointers in this data structure should not be traversed.  */
 173 extern int ggc_set_mark                 PARAMS ((const void *));
 174
 175 /* Return 1 if P has been marked, zero otherwise.
 176    P must have been allocated by the GC allocator; it mustn't point to
 177    static objects, stack variables, or memory allocated with malloc.  */
 178 extern int ggc_marked_p                 PARAMS ((const void *));
 179
 180 /* Callbacks to the languages.  */
 181
 182 /* This is the language's opportunity to mark nodes held through
 183    the lang_specific hooks in the tree.  */
 184 extern void lang_mark_tree              PARAMS ((union tree_node *));
 185
 186 /* The FALSE_LABEL_STACK, declared in except.h, has language-dependent
 187    semantics.  If a front-end needs to mark the false label stack, it
 188    should set this pointer to a non-NULL value.  Otherwise, no marking
 189    will be done.  */
 190 extern void (*lang_mark_false_label_stack) PARAMS ((struct label_node *));
 191
 192 /* Mark functions for various structs scattered about.  */
 193
 194 void mark_eh_status                     PARAMS ((struct eh_status *));
 195 void mark_emit_status                   PARAMS ((struct emit_status *));
 196 void mark_expr_status                   PARAMS ((struct expr_status *));
 197 void mark_stmt_status                   PARAMS ((struct stmt_status *));
 198 void mark_varasm_status                 PARAMS ((struct varasm_status *));
 199 void mark_optab                         PARAMS ((void *));
 200
 201 /* Statistics.  */
 202
 203 /* This structure contains the statistics common to all collectors.
 204    Particular collectors can extend this structure.  */
 205 typedef struct ggc_statistics
 206 {
 207   /* The Ith element is the number of nodes allocated with code I.  */
 208   unsigned num_trees[256];
 209   /* The Ith element is the number of bytes allocated by nodes with
 210      code I.  */
 211   size_t size_trees[256];
 212   /* The Ith element is the number of nodes allocated with code I.  */
 213   unsigned num_rtxs[256];
 214   /* The Ith element is the number of bytes allocated by nodes with
 215      code I.  */
 216   size_t size_rtxs[256];
 217   /* The total size of the tree nodes allocated.  */
 218   size_t total_size_trees;
 219   /* The total size of the RTL nodes allocated.  */
 220   size_t total_size_rtxs;
 221   /* The total number of tree nodes allocated.  */
 222   unsigned total_num_trees;
 223   /* The total number of RTL nodes allocated.  */
 224   unsigned total_num_rtxs;
 225 } ggc_statistics;
 226
 227 /* Return the number of bytes allocated at the indicated address.  */
 228 extern size_t ggc_get_size              PARAMS ((const void *));
 229
 230 /* Used by the various collectors to gather and print statistics that
 231    do not depend on the collector in use.  */
 232 extern void ggc_print_common_statistics PARAMS ((FILE *, ggc_statistics *));
 233
 234 /* Print allocation statistics.  */
 235 extern void ggc_print_statistics        PARAMS ((void));
 236 extern void stringpool_statistics       PARAMS ((void));