gcc/ggc.h

   1 /* Garbage collection for the GNU compiler.
   2    Copyright (C) 1998, 1999, 2000 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 2, or (at your option) any
   9 later version.
  10
  11 GNU CC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY 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 GNU CC; 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 "gansidecl.h"
  22 #include "varray.h"
  23
  24 /* Symbols are marked with `ggc' for `gcc gc' so as not to interfere with
  25    an external gc library that might be linked in.  */
  26
  27 /* Language-specific code defines this variable to be either one (if
  28    it wants garbage collection), or zero (if it does not).  */
  29 extern int ggc_p;
  30
  31 /* These structures are defined in various headers throughout the
  32    compiler.  However, rather than force everyone who includes this
  33    header to include all the headers in which they are declared, we
  34    just forward-declare them here.  */
  35 struct eh_status;
  36 struct emit_status;
  37 struct expr_status;
  38 struct hash_table;
  39 struct label_node;
  40 struct rtx_def;
  41 struct rtvec_def;
  42 struct stmt_status;
  43 union  tree_node;
  44 struct varasm_status;
  45
  46 /* Constants for general use.  */
  47 extern char *empty_string;
  48
  49 /* Trees that have been marked, but whose children still need marking.  */
  50 extern varray_type ggc_pending_trees;
  51
  52 /* Manipulate global roots that are needed between calls to gc.  */
  53 void ggc_add_root PARAMS ((void *base, int nelt, int size, void (*)(void *)));
  54 void ggc_add_rtx_root PARAMS ((struct rtx_def **, int nelt));
  55 void ggc_add_tree_root PARAMS ((union tree_node **, int nelt));
  56 void ggc_add_string_root PARAMS ((char **, int nelt));
  57 void ggc_add_rtx_varray_root PARAMS ((struct varray_head_tag **, int nelt));
  58 void ggc_add_tree_varray_root PARAMS ((struct varray_head_tag **, int nelt));
  59 void ggc_add_tree_hash_table_root PARAMS ((struct hash_table **, int nelt));
  60 void ggc_del_root PARAMS ((void *base));
  61
  62 /* Mark nodes from the gc_add_root callback.  These functions follow
  63    pointers to mark other objects too.  */
  64 extern void ggc_mark_rtx_varray PARAMS ((struct varray_head_tag *));
  65 extern void ggc_mark_tree_varray PARAMS ((struct varray_head_tag *));
  66 extern void ggc_mark_tree_hash_table PARAMS ((struct hash_table *));
  67 extern void ggc_mark_roots PARAMS ((void));
  68
  69 extern void ggc_mark_rtx_children PARAMS ((struct rtx_def *));
  70 extern void ggc_mark_rtvec_children PARAMS ((struct rtvec_def *));
  71
  72 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  73    to true.  Otherwise evaluate to false.  */
  74 #define ggc_test_and_set_mark(EXPR) \
  75   ((EXPR) != NULL && ! ggc_set_mark (EXPR))
  76
  77 #define ggc_mark_rtx(EXPR)                      \
  78   do {                                          \
  79     rtx r__ = (EXPR);                           \
  80     if (ggc_test_and_set_mark (r__))            \
  81       ggc_mark_rtx_children (r__);              \
  82   } while (0)
  83
  84 #define ggc_mark_tree(EXPR)                             \
  85   do {                                                  \
  86     tree t__ = (EXPR);                                  \
  87     if (ggc_test_and_set_mark (t__))                    \
  88       VARRAY_PUSH_TREE (ggc_pending_trees, t__);        \
  89   } while (0)
  90
  91 #define ggc_mark_rtvec(EXPR)                    \
  92   do {                                          \
  93     rtvec v__ = (EXPR);                         \
  94     if (ggc_test_and_set_mark (v__))            \
  95       ggc_mark_rtvec_children (v__);            \
  96   } while (0)
  97
  98 #define ggc_mark_string(EXPR)                   \
  99   do {                                          \
 100     const char *s__ = (EXPR);                   \
 101     if (s__ != NULL)                            \
 102       ggc_set_mark (s__);                       \
 103   } while (0)
 104
 105 #define ggc_mark(EXPR)                          \
 106   do {                                          \
 107     const void *a__ = (EXPR);                   \
 108     if (a__ != NULL)                            \
 109       ggc_set_mark (a__);                       \
 110   } while (0)
 111
 112 /* Mark, but only if it was allocated in collectable memory.  */
 113 extern void ggc_mark_if_gcable PARAMS ((const void *));
 114
 115 /* A GC implementation must provide these functions.  */
 116
 117 /* Initialize the garbage collector.   */
 118 extern void init_ggc PARAMS ((void));
 119
 120 /* Start a new GGC context.  Memory allocated in previous contexts
 121    will not be collected while the new context is active.  */
 122 extern void ggc_push_context PARAMS ((void));
 123
 124 /* Finish a GC context.  Any uncollected memory in the new context
 125    will be merged with the old context.  */
 126 extern void ggc_pop_context PARAMS ((void));
 127
 128 /* Allocation.  */
 129
 130 /* The internal primitive.  */
 131 void *ggc_alloc PARAMS ((size_t));
 132 /* Like ggc_alloc, but allocates cleared memory.  */
 133 void *ggc_alloc_cleared PARAMS ((size_t));
 134
 135 #define ggc_alloc_rtx(NSLOTS)                                             \
 136   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 137                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 138
 139 #define ggc_alloc_rtvec(NELT)                                             \
 140   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 141                                    + ((NELT) - 1) * sizeof (rtx)))
 142
 143 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 144
 145 char *ggc_alloc_string PARAMS ((const char *contents, int length));
 146
 147 /* Invoke the collector.  This is really just a hint, but in the case of
 148    the simple collector, the only time it will happen.  */
 149 void ggc_collect PARAMS ((void));
 150
 151 /* Actually set the mark on a particular region of memory, but don't
 152    follow pointers.  This function is called by ggc_mark_*.  It
 153    returns zero if the object was not previously marked; non-zero if
 154    the object was already marked, or if, for any other reason,
 155    pointers in this data structure should not be traversed.  */
 156 int ggc_set_mark PARAMS ((const void *));
 157
 158 /* Callbacks to the languages.  */
 159
 160 /* This is the language's opportunity to mark nodes held through
 161    the lang_specific hooks in the tree.  */
 162 void lang_mark_tree PARAMS ((union tree_node *));
 163
 164 /* The FALSE_LABEL_STACK, declared in except.h, has
 165    language-dependent semantics.  Each front-end should define this
 166    function appropriately.  */
 167 void lang_mark_false_label_stack PARAMS ((struct label_node *));
 168
 169 /* Mark functions for various structs scattered about.  */
 170
 171 void mark_eh_status PARAMS ((struct eh_status *));
 172 void mark_emit_status PARAMS ((struct emit_status *));
 173 void mark_expr_status PARAMS ((struct expr_status *));
 174 void mark_stmt_status PARAMS ((struct stmt_status *));
 175 void mark_varasm_status PARAMS ((struct varasm_status *));
 176 void mark_optab PARAMS ((void *));
 177
 178 /* Statistics.  */
 179
 180 /* This structure contains the statistics common to all collectors.
 181    Particular collectors can extend this structure.  */
 182 typedef struct ggc_statistics
 183 {
 184   /* The Ith element is the number of nodes allocated with code I.  */
 185   unsigned num_trees[256];
 186   /* The Ith element is the number of bytes allocated by nodes with
 187      code I.  */
 188   size_t size_trees[256];
 189   /* The Ith element is the number of nodes allocated with code I.  */
 190   unsigned num_rtxs[256];
 191   /* The Ith element is the number of bytes allocated by nodes with
 192      code I.  */
 193   size_t size_rtxs[256];
 194   /* The total size of the tree nodes allocated.  */
 195   size_t total_size_trees;
 196   /* The total size of the RTL nodes allocated.  */
 197   size_t total_size_rtxs;
 198   /* The total number of tree nodes allocated.  */
 199   unsigned total_num_trees;
 200   /* The total number of RTL nodes allocated.  */
 201   unsigned total_num_rtxs;
 202 } ggc_statistics;
 203
 204 /* Return the number of bytes allocated at the indicated address.  */
 205 size_t ggc_get_size PARAMS ((const void *));
 206
 207 /* Used by the various collectors to gather and print statistics that
 208    do not depend on the collector in use.  */
 209 void ggc_print_statistics PARAMS ((FILE *, ggc_statistics *));
 210
 211 /* Print allocation statistics.  */
 212 extern void ggc_page_print_statistics PARAMS ((void));