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
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
/* Copyright (C) 2012 Matthew Fluet.
* Copyright (C) 1999-2006 Henry Cejtin, Matthew Fluet, Suresh
* Jagannathan, and Stephen Weeks.
* Copyright (C) 1997-2000 NEC Research Institute.
*
* MLton is released under a BSD-style license.
* See the file MLton-LICENSE for details.
*/
const char* objectTypeTagToString (GC_objectTypeTag tag) {
switch (tag) {
case ARRAY_TAG:
return "ARRAY";
case NORMAL_TAG:
return "NORMAL";
case STACK_TAG:
return "STACK";
case WEAK_TAG:
return "WEAK";
default:
die ("bad GC_objectTypeTag %u", tag);
}
}
/* getHeaderp (p)
*
* Returns a pointer to the header for the object pointed to by p.
*/
GC_header* getHeaderp (pointer p) {
return (GC_header*)(p
- GC_HEADER_SIZE);
}
/* getHeader (p)
*
* Returns the header for the object pointed to by p.
*/
GC_header getHeader (pointer p) {
return *(getHeaderp(p));
}
/*
* Build the header for an object, given the index to its type info.
*/
GC_header buildHeaderFromTypeIndex (uint32_t t) {
assert (t < TWOPOWER (TYPE_INDEX_BITS));
return 1 | (t << 1);
}
void splitHeader(GC_state s, GC_header header,
GC_objectTypeTag *tagRet, bool *hasIdentityRet,
uint16_t *bytesNonObjptrsRet, uint16_t *numObjptrsRet) {
unsigned int objectTypeIndex;
GC_objectType objectType;
GC_objectTypeTag tag;
bool hasIdentity;
uint16_t bytesNonObjptrs, numObjptrs;
assert (1 == (header & GC_VALID_HEADER_MASK));
objectTypeIndex = (header & TYPE_INDEX_MASK) >> TYPE_INDEX_SHIFT;
assert (objectTypeIndex < s->objectTypesLength);
objectType = &(s->objectTypes[objectTypeIndex]);
tag = objectType->tag;
hasIdentity = objectType->hasIdentity;
bytesNonObjptrs = objectType->bytesNonObjptrs;
numObjptrs = objectType->numObjptrs;
if (DEBUG_DETAILED)
fprintf (stderr,
"splitHeader ("FMTHDR")"
" objectTypeIndex = %u"
" tag = %s"
" hasIdentity = %s"
" bytesNonObjptrs = %"PRIu16
" numObjptrs = %"PRIu16"\n",
header,
objectTypeIndex,
objectTypeTagToString(tag),
boolToString(hasIdentity),
bytesNonObjptrs, numObjptrs);
if (tagRet != NULL)
*tagRet = tag;
if (hasIdentityRet != NULL)
*hasIdentityRet = hasIdentity;
if (bytesNonObjptrsRet != NULL)
*bytesNonObjptrsRet = bytesNonObjptrs;
if (numObjptrsRet != NULL)
*numObjptrsRet = numObjptrs;
}
/* advanceToObjectData (s, p)
*
* If p points at the beginning of an object, then advanceToObjectData
* returns a pointer to the start of the object data.
*/
pointer advanceToObjectData (ARG_USED_FOR_ASSERT GC_state s, pointer p) {
GC_header header;
pointer res;
assert (isFrontierAligned (s, p));
header = *(GC_header*)p;
if (0 == header)
/* Looking at the counter word in an array. */
res = p + GC_ARRAY_HEADER_SIZE;
else
/* Looking at a header word. */
res = p + GC_NORMAL_HEADER_SIZE;
assert (isAligned ((uintptr_t)res, s->alignment));
if (DEBUG_DETAILED)
fprintf (stderr, FMTPTR" = advanceToObjectData ("FMTPTR")\n",
(uintptr_t)res, (uintptr_t)p);
return res;
}
|
