91 lines
3.0 KiB
C
91 lines
3.0 KiB
C
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/*
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* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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* Copyright (c) 1991, 1992 by Xerox Corporation. All rights reserved.
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* Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*/
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#include "private/gc_priv.h"
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/* Routines for maintaining maps describing heap block
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* layouts for various object sizes. Allows fast pointer validity checks
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* and fast location of object start locations on machines (such as SPARC)
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* with slow division.
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*/
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/* Consider pointers that are offset bytes displaced from the beginning */
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/* of an object to be valid. */
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GC_API void GC_CALL GC_register_displacement(size_t offset)
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{
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DCL_LOCK_STATE;
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LOCK();
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GC_register_displacement_inner(offset);
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UNLOCK();
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}
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GC_INNER void GC_register_displacement_inner(size_t offset)
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{
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if (offset >= VALID_OFFSET_SZ) {
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ABORT("Bad argument to GC_register_displacement");
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}
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if (!GC_valid_offsets[offset]) {
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GC_valid_offsets[offset] = TRUE;
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GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
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}
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}
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#ifdef MARK_BIT_PER_GRANULE
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/* Add a heap block map for objects of size granules to obj_map. */
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/* Return FALSE on failure. */
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/* A size of 0 granules is used for large objects. */
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GC_INNER GC_bool GC_add_map_entry(size_t granules)
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{
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unsigned displ;
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unsigned short * new_map;
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if (granules > BYTES_TO_GRANULES(MAXOBJBYTES)) granules = 0;
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if (GC_obj_map[granules] != 0) {
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return(TRUE);
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}
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new_map = (unsigned short *)GC_scratch_alloc(MAP_LEN * sizeof(short));
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if (new_map == 0) return(FALSE);
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GC_COND_LOG_PRINTF(
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"Adding block map for size of %u granules (%u bytes)\n",
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(unsigned)granules, (unsigned)GRANULES_TO_BYTES(granules));
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if (granules == 0) {
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for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) {
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new_map[displ] = 1; /* Nonzero to get us out of marker fast path. */
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}
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} else {
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for (displ = 0; displ < BYTES_TO_GRANULES(HBLKSIZE); displ++) {
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new_map[displ] = (unsigned short)(displ % granules);
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}
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}
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GC_obj_map[granules] = new_map;
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return(TRUE);
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}
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#endif /* MARK_BIT_PER_GRANULE */
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GC_INNER void GC_initialize_offsets(void)
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{
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unsigned i;
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if (GC_all_interior_pointers) {
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for (i = 0; i < VALID_OFFSET_SZ; ++i)
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GC_valid_offsets[i] = TRUE;
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} else {
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BZERO(GC_valid_offsets, sizeof(GC_valid_offsets));
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for (i = 0; i < sizeof(word); ++i)
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GC_modws_valid_offsets[i] = FALSE;
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}
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}
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