-
Notifications
You must be signed in to change notification settings - Fork 401
/
obj_map.c
88 lines (77 loc) · 2.75 KB
/
obj_map.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991, 1992 by Xerox Corporation. All rights reserved.
* Copyright (c) 1999-2001 by Hewlett-Packard Company. All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose, provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/
#include "private/gc_priv.h"
/* Routines for maintaining maps describing heap block
* layouts for various object sizes. Allows fast pointer validity checks
* and fast location of object start locations on machines (such as SPARC)
* with slow division.
*/
/* Consider pointers that are offset bytes displaced from the beginning */
/* of an object to be valid. */
GC_API void GC_CALL GC_register_displacement(size_t offset)
{
LOCK();
GC_register_displacement_inner(offset);
UNLOCK();
}
GC_INNER void GC_register_displacement_inner(size_t offset)
{
GC_ASSERT(I_HOLD_LOCK());
if (offset >= VALID_OFFSET_SZ) {
ABORT("Bad argument to GC_register_displacement");
}
if (!GC_valid_offsets[offset]) {
GC_valid_offsets[offset] = TRUE;
GC_modws_valid_offsets[offset % sizeof(ptr_t)] = TRUE;
}
}
#ifndef MARK_BIT_PER_OBJ
GC_INNER GC_bool GC_add_map_entry(size_t lg)
{
size_t displ;
unsigned short * new_map;
GC_ASSERT(I_HOLD_LOCK());
if (lg > BYTES_TO_GRANULES(MAXOBJBYTES)) lg = 0;
if (GC_obj_map[lg] != 0) return TRUE;
new_map = (unsigned short *)GC_scratch_alloc(OBJ_MAP_LEN * sizeof(short));
if (EXPECT(NULL == new_map, FALSE)) return FALSE;
GC_COND_LOG_PRINTF(
"Adding block map for size of %u granules (%u bytes)\n",
(unsigned)lg, (unsigned)GRANULES_TO_BYTES(lg));
if (0 == lg) {
for (displ = 0; displ < OBJ_MAP_LEN; displ++) {
new_map[displ] = 1; /* Nonzero to get us out of marker fast path. */
}
} else {
for (displ = 0; displ < OBJ_MAP_LEN; displ++) {
new_map[displ] = (unsigned short)(displ % lg);
}
}
GC_obj_map[lg] = new_map;
return TRUE;
}
#endif /* !MARK_BIT_PER_OBJ */
GC_INNER void GC_initialize_offsets(void)
{
size_t i;
if (GC_all_interior_pointers) {
for (i = 0; i < VALID_OFFSET_SZ; ++i)
GC_valid_offsets[i] = TRUE;
} else {
BZERO(GC_valid_offsets, sizeof(GC_valid_offsets));
for (i = 0; i < sizeof(ptr_t); ++i)
GC_modws_valid_offsets[i] = FALSE;
}
}