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.
6 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
7 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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.
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)
24 # include "private/gc_priv.h"
26 map_entry_type * GC_invalid_map = 0;
28 /* Invalidate the object map associated with a block. Free blocks */
29 /* are identified by invalid maps. */
30 void GC_invalidate_map(hhdr)
35 if (GC_invalid_map == 0) {
36 GC_invalid_map = (map_entry_type *)GC_scratch_alloc(MAP_SIZE);
37 if (GC_invalid_map == 0) {
39 "Cant initialize GC_invalid_map: insufficient memory\n");
42 for (displ = 0; displ < HBLKSIZE; displ++) {
43 MAP_ENTRY(GC_invalid_map, displ) = OBJ_INVALID;
46 hhdr -> hb_map = GC_invalid_map;
49 /* Consider pointers that are offset bytes displaced from the beginning */
50 /* of an object to be valid. */
52 # if defined(__STDC__) || defined(__cplusplus)
53 void GC_register_displacement(GC_word offset)
55 void GC_register_displacement(offset)
63 GC_register_displacement_inner(offset);
68 void GC_register_displacement_inner(offset)
72 word map_entry = BYTES_TO_WORDS(offset);
74 if (offset >= VALID_OFFSET_SZ) {
75 ABORT("Bad argument to GC_register_displacement");
77 if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
78 if (!GC_valid_offsets[offset]) {
79 GC_valid_offsets[offset] = TRUE;
80 GC_modws_valid_offsets[offset % sizeof(word)] = TRUE;
81 if (!GC_all_interior_pointers) {
82 for (i = 0; i <= MAXOBJSZ; i++) {
83 if (GC_obj_map[i] != 0) {
85 GC_obj_map[i][offset] = (map_entry_type)map_entry;
88 register unsigned lb = WORDS_TO_BYTES(i);
91 for (j = offset; j < HBLKSIZE; j += lb) {
92 GC_obj_map[i][j] = (map_entry_type)map_entry;
103 /* Add a heap block map for objects of size sz to obj_map. */
104 /* Return FALSE on failure. */
105 GC_bool GC_add_map_entry(sz)
108 register unsigned obj_start;
109 register unsigned displ;
110 register map_entry_type * new_map;
113 if (sz > MAXOBJSZ) sz = 0;
114 if (GC_obj_map[sz] != 0) {
117 new_map = (map_entry_type *)GC_scratch_alloc(MAP_SIZE);
118 if (new_map == 0) return(FALSE);
120 GC_printf1("Adding block map for size %lu\n", (unsigned long)sz);
122 for (displ = 0; displ < HBLKSIZE; displ++) {
123 MAP_ENTRY(new_map,displ) = OBJ_INVALID;
126 for(displ = 0; displ <= HBLKSIZE; displ++) {
127 if (OFFSET_VALID(displ)) {
128 map_entry = BYTES_TO_WORDS(displ);
129 if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
130 MAP_ENTRY(new_map,displ) = (map_entry_type)map_entry;
135 obj_start + WORDS_TO_BYTES(sz) <= HBLKSIZE;
136 obj_start += WORDS_TO_BYTES(sz)) {
137 for (displ = 0; displ < WORDS_TO_BYTES(sz); displ++) {
138 if (OFFSET_VALID(displ)) {
139 map_entry = BYTES_TO_WORDS(displ);
140 if (map_entry > MAX_OFFSET) map_entry = OFFSET_TOO_BIG;
141 MAP_ENTRY(new_map, obj_start + displ) =
142 (map_entry_type)map_entry;
147 GC_obj_map[sz] = new_map;