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 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 /* These structures are defined in various headers throughout the
  28    compiler.  However, rather than force everyone who includes this
  29    header to include all the headers in which they are declared, we
  30    just forward-declare them here.  */
  31 struct eh_status;
  32 struct emit_status;
  33 struct expr_status;
  34 struct hash_table;
  35 struct label_node;
  36 struct rtx_def;
  37 struct rtvec_def;
  38 struct stmt_status;
  39 union  tree_node;
  40 struct varasm_status;
  41
  42 /* Constants for general use.  */
  43 extern const char empty_string[];       /* empty string */
  44 extern const char digit_vector[];       /* "0" .. "9" */
  45 #define digit_string(d) (digit_vector + ((d) * 2))
  46
  47 /* Trees that have been marked, but whose children still need marking.  */
  48 extern varray_type ggc_pending_trees;
  49
  50 /* Manipulate global roots that are needed between calls to gc.  */
  51 void ggc_add_root PARAMS ((void *base, int nelt, int size, void (*)(void *)));
  52 void ggc_add_rtx_root PARAMS ((struct rtx_def **, int nelt));
  53 void ggc_add_tree_root PARAMS ((union tree_node **, int nelt));
  54 void ggc_add_rtx_varray_root PARAMS ((struct varray_head_tag **, int nelt));
  55 void ggc_add_tree_varray_root PARAMS ((struct varray_head_tag **, int nelt));
  56 void ggc_add_tree_hash_table_root PARAMS ((struct hash_table **, int nelt));
  57 void ggc_del_root PARAMS ((void *base));
  58
  59 /* Mark nodes from the gc_add_root callback.  These functions follow
  60    pointers to mark other objects too.  */
  61 extern void ggc_mark_rtx_varray PARAMS ((struct varray_head_tag *));
  62 extern void ggc_mark_tree_varray PARAMS ((struct varray_head_tag *));
  63 extern void ggc_mark_tree_hash_table PARAMS ((struct hash_table *));
  64 extern void ggc_mark_roots PARAMS ((void));
  65
  66 extern void ggc_mark_rtx_children PARAMS ((struct rtx_def *));
  67 extern void ggc_mark_rtvec_children PARAMS ((struct rtvec_def *));
  68
  69 /* If EXPR is not NULL and previously unmarked, mark it and evaluate
  70    to true.  Otherwise evaluate to false.  */
  71 #define ggc_test_and_set_mark(EXPR) \
  72   ((EXPR) != NULL && ! ggc_set_mark (EXPR))
  73
  74 #define ggc_mark_rtx(EXPR)                      \
  75   do {                                          \
  76     rtx r__ = (EXPR);                           \
  77     if (ggc_test_and_set_mark (r__))            \
  78       ggc_mark_rtx_children (r__);              \
  79   } while (0)
  80
  81 #define ggc_mark_tree(EXPR)                             \
  82   do {                                                  \
  83     tree t__ = (EXPR);                                  \
  84     if (ggc_test_and_set_mark (t__))                    \
  85       VARRAY_PUSH_TREE (ggc_pending_trees, t__);        \
  86   } while (0)
  87
  88 #define ggc_mark_rtvec(EXPR)                    \
  89   do {                                          \
  90     rtvec v__ = (EXPR);                         \
  91     if (ggc_test_and_set_mark (v__))            \
  92       ggc_mark_rtvec_children (v__);            \
  93   } while (0)
  94
  95 #define ggc_mark(EXPR)                          \
  96   do {                                          \
  97     const void *a__ = (EXPR);                   \
  98     if (a__ != NULL)                            \
  99       ggc_set_mark (a__);                       \
 100   } while (0)
 101
 102 /* A GC implementation must provide these functions.  */
 103
 104 /* Initialize the garbage collector.   */
 105 extern void init_ggc PARAMS ((void));
 106 extern void init_stringpool PARAMS ((void));
 107
 108 /* Start a new GGC context.  Memory allocated in previous contexts
 109    will not be collected while the new context is active.  */
 110 extern void ggc_push_context PARAMS ((void));
 111
 112 /* Finish a GC context.  Any uncollected memory in the new context
 113    will be merged with the old context.  */
 114 extern void ggc_pop_context PARAMS ((void));
 115
 116 /* Allocation.  */
 117
 118 /* The internal primitive.  */
 119 void *ggc_alloc PARAMS ((size_t));
 120 /* Like ggc_alloc, but allocates cleared memory.  */
 121 void *ggc_alloc_cleared PARAMS ((size_t));
 122
 123 #define ggc_alloc_rtx(NSLOTS)                                             \
 124   ((struct rtx_def *) ggc_alloc (sizeof (struct rtx_def)                  \
 125                                  + ((NSLOTS) - 1) * sizeof (rtunion)))
 126
 127 #define ggc_alloc_rtvec(NELT)                                             \
 128   ((struct rtvec_def *) ggc_alloc (sizeof (struct rtvec_def)              \
 129                                    + ((NELT) - 1) * sizeof (rtx)))
 130
 131 #define ggc_alloc_tree(LENGTH) ((union tree_node *) ggc_alloc (LENGTH))
 132
 133 /* Allocate a gc-able string, and fill it with LENGTH bytes from CONTENTS.
 134    If LENGTH is -1, then CONTENTS is assumed to be a
 135    null-terminated string and the memory sized accordingly.  */
 136 const char *ggc_alloc_string PARAMS ((const char *contents, int length));
 137
 138 /* Make a copy of S, in GC-able memory.  */
 139 #define ggc_strdup(S) ggc_alloc_string((S), -1)
 140
 141 /* Invoke the collector.  Garbage collection occurs only when this
 142    function is called, not during allocations.  */
 143 void ggc_collect PARAMS ((void));
 144
 145 /* Actually set the mark on a particular region of memory, but don't
 146    follow pointers.  This function is called by ggc_mark_*.  It
 147    returns zero if the object was not previously marked; non-zero if
 148    the object was already marked, or if, for any other reason,
 149    pointers in this data structure should not be traversed.  */
 150 int ggc_set_mark PARAMS ((const void *));
 151
 152 /* Callbacks to the languages.  */
 153
 154 /* This is the language's opportunity to mark nodes held through
 155    the lang_specific hooks in the tree.  */
 156 void lang_mark_tree PARAMS ((union tree_node *));
 157
 158 /* The FALSE_LABEL_STACK, declared in except.h, has language-dependent
 159    semantics.  If a front-end needs to mark the false label stack, it
 160    should set this pointer to a non-NULL value.  Otherwise, no marking
 161    will be done.  */
 162 extern void (*lang_mark_false_label_stack) PARAMS ((struct label_node *));
 163
 164 /* Mark functions for various structs scattered about.  */
 165
 166 void mark_eh_status PARAMS ((struct eh_status *));
 167 void mark_emit_status PARAMS ((struct emit_status *));
 168 void mark_expr_status PARAMS ((struct expr_status *));
 169 void mark_stmt_status PARAMS ((struct stmt_status *));
 170 void mark_varasm_status PARAMS ((struct varasm_status *));
 171 void mark_optab PARAMS ((void *));
 172
 173 /* Statistics.  */
 174
 175 /* This structure contains the statistics common to all collectors.
 176    Particular collectors can extend this structure.  */
 177 typedef struct ggc_statistics
 178 {
 179   /* The Ith element is the number of nodes allocated with code I.  */
 180   unsigned num_trees[256];
 181   /* The Ith element is the number of bytes allocated by nodes with
 182      code I.  */
 183   size_t size_trees[256];
 184   /* The Ith element is the number of nodes allocated with code I.  */
 185   unsigned num_rtxs[256];
 186   /* The Ith element is the number of bytes allocated by nodes with
 187      code I.  */
 188   size_t size_rtxs[256];
 189   /* The total size of the tree nodes allocated.  */
 190   size_t total_size_trees;
 191   /* The total size of the RTL nodes allocated.  */
 192   size_t total_size_rtxs;
 193   /* The total number of tree nodes allocated.  */
 194   unsigned total_num_trees;
 195   /* The total number of RTL nodes allocated.  */
 196   unsigned total_num_rtxs;
 197 } ggc_statistics;
 198
 199 /* Return the number of bytes allocated at the indicated address.  */
 200 size_t ggc_get_size PARAMS ((const void *));
 201
 202 /* Used by the various collectors to gather and print statistics that
 203    do not depend on the collector in use.  */
 204 void ggc_print_common_statistics PARAMS ((FILE *, ggc_statistics *));
 205
 206 /* Print allocation statistics.  */
 207 extern void ggc_print_statistics PARAMS ((void));
 208 void stringpool_statistics PARAMS ((void));