ceph/src/boost/tools/build/src/engine/boehm_gc/obj_map.c

   1 /*
   2  * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
   3  * Copyright (c) 1991, 1992 by Xerox Corporation.  All rights reserved.
   4  * Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved.
   5  *
   6  * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
   7  * OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
   8  *
   9  * Permission is hereby granted to use or copy this program
  10  * for any purpose,  provided the above notices are retained on all copies.
  11  * Permission to modify the code and to distribute modified code is granted,
  12  * provided the above notices are retained, and a notice that the code was
  13  * modified is included with the above copyright notice.
  14  */
  15
  16 /* Routines for maintaining maps describing heap block
  17  * layouts for various object sizes.  Allows fast pointer validity checks
  18  * and fast location of object start locations on machines (such as SPARC)
  19  * with slow division.
  20  */
  21
  22 # include "private/gc_priv.h"
  23
  24 /* Consider pointers that are offset bytes displaced from the beginning */
  25 /* of an object to be valid.                                            */
  26
  27 void GC_register_displacement(size_t offset)
  28 {
  29     DCL_LOCK_STATE;
  30
  31     LOCK();
  32     GC_register_displacement_inner(offset);
  33     UNLOCK();
  34 }
  35
  36 void GC_register_displacement_inner(size_t offset)
  37 {
  38     if (offset >= VALID_OFFSET_SZ) {
  39         ABORT("Bad argument to GC_register_displacement");
  40     }
  41     if (!GC_valid_offsets[offset]) {
  42       GC_valid_offsets[offset] = TRUE;
  43       GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
  44     }
  45 }
  46
  47 #ifdef MARK_BIT_PER_GRANULE
  48 /* Add a heap block map for objects of size granules to obj_map.        */
  49 /* Return FALSE on failure.                                             */
  50 /* A size of 0 granules is used for large objects.                      */
  51 GC_bool GC_add_map_entry(size_t granules)
  52 {
  53     unsigned displ;
  54     short * new_map;
  55
  56     if (granules > BYTES_TO_GRANULES(MAXOBJBYTES)) granules = 0;
  57     if (GC_obj_map[granules] != 0) {
  58         return(TRUE);
  59     }
  60     new_map = (short *)GC_scratch_alloc(MAP_LEN * sizeof(short));
  61     if (new_map == 0) return(FALSE);
  62     if (GC_print_stats)
  63         GC_printf("Adding block map for size of %u granules (%u bytes)\n",
  64                   (unsigned)granules, (unsigned)(GRANULES_TO_BYTES(granules)));
  65     if (granules == 0) {
  66       for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) {
  67         new_map[displ] = 1;  /* Nonzero to get us out of marker fast path. */
  68       }
  69     } else {
  70       for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) {
  71         new_map[displ] = (short)(displ % granules);
  72       }
  73     }
  74     GC_obj_map[granules] = new_map;
  75     return(TRUE);
  76 }
  77 #endif
  78
  79 static GC_bool offsets_initialized = FALSE;
  80
  81 void GC_initialize_offsets(void)
  82 {
  83     if (!offsets_initialized) {
  84       int i;
  85       if (GC_all_interior_pointers) {
  86         for (i = 0; i < VALID_OFFSET_SZ; ++i) GC_valid_offsets[i] = TRUE;
  87       }
  88       offsets_initialized = TRUE;
  89     }
  90 }