| 1 | /*
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| 2 | * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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| 3 | * Copyright (c) 1991, 1992 by Xerox Corporation. All rights reserved.
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| 4 | * Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved.
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| 5 | *
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| 6 | * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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| 7 | * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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| 8 | *
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| 9 | * Permission is hereby granted to use or copy this program
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| 10 | * for any purpose, provided the above notices are retained on all copies.
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| 11 | * Permission to modify the code and to distribute modified code is granted,
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| 12 | * provided the above notices are retained, and a notice that the code was
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| 13 | * modified is included with the above copyright notice.
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| 14 | */
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| 15 |
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| 16 | /* Routines for maintaining maps describing heap block
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| 17 | * layouts for various object sizes. Allows fast pointer validity checks
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| 18 | * and fast location of object start locations on machines (such as SPARC)
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| 19 | * with slow division.
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| 20 | */
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| 21 |
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| 22 | # include "private/gc_priv.h"
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| 23 |
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| 24 | map_entry_type * GC_invalid_map = 0;
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| 25 |
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| 26 | /* Invalidate the object map associated with a block. Free blocks */
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| 27 | /* are identified by invalid maps. */
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| 28 | void GC_invalidate_map(hhdr)
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| 29 | hdr *hhdr;
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| 30 | {
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| 31 | register int displ;
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| 32 |
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| 33 | if (GC_invalid_map == 0) {
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| 34 | GC_invalid_map = (map_entry_type *)GC_scratch_alloc(MAP_SIZE);
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| 35 | if (GC_invalid_map == 0) {
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| 36 | GC_err_printf0(
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| 37 | "Cant initialize GC_invalid_map: insufficient memory\n");
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| 38 | EXIT();
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| 39 | }
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| 40 | for (displ = 0; displ < HBLKSIZE; displ++) {
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| 41 | MAP_ENTRY(GC_invalid_map, displ) = OBJ_INVALID;
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| 42 | }
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| 43 | }
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| 44 | hhdr -> hb_map = GC_invalid_map;
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| 45 | }
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| 46 |
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| 47 | /* Consider pointers that are offset bytes displaced from the beginning */
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| 48 | /* of an object to be valid. */
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| 49 |
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| 50 | # if defined(__STDC__) || defined(__cplusplus)
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| 51 | void GC_register_displacement(GC_word offset)
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| 52 | # else
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| 53 | void GC_register_displacement(offset)
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| 54 | GC_word offset;
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| 55 | # endif
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| 56 | {
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| 57 | DCL_LOCK_STATE;
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| 58 |
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| 59 | DISABLE_SIGNALS();
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| 60 | LOCK();
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| 61 | GC_register_displacement_inner(offset);
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| 62 | UNLOCK();
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| 63 | ENABLE_SIGNALS();
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| 64 | }
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| 65 |
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| 66 | void GC_register_displacement_inner(offset)
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| 67 | word offset;
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| 68 | {
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| 69 | register unsigned i;
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| 70 | word map_entry = BYTES_TO_WORDS(offset);
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| 71 |
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| 72 | if (offset >= VALID_OFFSET_SZ) {
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| 73 | ABORT("Bad argument to GC_register_displacement");
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| 74 | }
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| 75 | if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
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| 76 | if (!GC_valid_offsets[offset]) {
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| 77 | GC_valid_offsets[offset] = TRUE;
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| 78 | GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
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| 79 | if (!GC_all_interior_pointers) {
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| 80 | for (i = 0; i <= MAXOBJSZ; i++) {
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| 81 | if (GC_obj_map[i] != 0) {
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| 82 | if (i == 0) {
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| 83 | GC_obj_map[i][offset] = (map_entry_type)map_entry;
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| 84 | } else {
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| 85 | register unsigned j;
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| 86 | register unsigned lb = WORDS_TO_BYTES(i);
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| 87 |
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| 88 | if (offset < lb) {
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| 89 | for (j = offset; j < HBLKSIZE; j += lb) {
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| 90 | GC_obj_map[i][j] = (map_entry_type)map_entry;
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| 91 | }
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| 92 | }
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| 93 | }
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| 94 | }
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| 95 | }
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| 96 | }
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| 97 | }
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| 98 | }
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| 99 |
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| 100 |
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