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
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
|
// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "v8.h"
#include "objects.h"
#include "transitions-inl.h"
#include "utils.h"
namespace v8 {
namespace internal {
Handle<TransitionArray> TransitionArray::Allocate(Isolate* isolate,
int number_of_transitions) {
Handle<FixedArray> array =
isolate->factory()->NewFixedArray(ToKeyIndex(number_of_transitions));
array->set(kPrototypeTransitionsIndex, Smi::FromInt(0));
return Handle<TransitionArray>::cast(array);
}
Handle<TransitionArray> TransitionArray::AllocateSimple(Isolate* isolate,
Handle<Map> target) {
Handle<FixedArray> array =
isolate->factory()->NewFixedArray(kSimpleTransitionSize);
array->set(kSimpleTransitionTarget, *target);
return Handle<TransitionArray>::cast(array);
}
void TransitionArray::NoIncrementalWriteBarrierCopyFrom(TransitionArray* origin,
int origin_transition,
int target_transition) {
NoIncrementalWriteBarrierSet(target_transition,
origin->GetKey(origin_transition),
origin->GetTarget(origin_transition));
}
static bool InsertionPointFound(Name* key1, Name* key2) {
return key1->Hash() > key2->Hash();
}
Handle<TransitionArray> TransitionArray::NewWith(Handle<Map> map,
Handle<Name> name,
Handle<Map> target,
SimpleTransitionFlag flag) {
Handle<TransitionArray> result;
Isolate* isolate = name->GetIsolate();
if (flag == SIMPLE_TRANSITION) {
result = AllocateSimple(isolate, target);
} else {
result = Allocate(isolate, 1);
result->NoIncrementalWriteBarrierSet(0, *name, *target);
}
result->set_back_pointer_storage(map->GetBackPointer());
return result;
}
Handle<TransitionArray> TransitionArray::ExtendToFullTransitionArray(
Handle<Map> containing_map) {
ASSERT(!containing_map->transitions()->IsFullTransitionArray());
int nof = containing_map->transitions()->number_of_transitions();
// A transition array may shrink during GC.
Handle<TransitionArray> result = Allocate(containing_map->GetIsolate(), nof);
DisallowHeapAllocation no_gc;
int new_nof = containing_map->transitions()->number_of_transitions();
if (new_nof != nof) {
ASSERT(new_nof == 0);
result->Shrink(ToKeyIndex(0));
} else if (nof == 1) {
result->NoIncrementalWriteBarrierCopyFrom(
containing_map->transitions(), kSimpleTransitionIndex, 0);
}
result->set_back_pointer_storage(
containing_map->transitions()->back_pointer_storage());
return result;
}
Handle<TransitionArray> TransitionArray::CopyInsert(Handle<Map> map,
Handle<Name> name,
Handle<Map> target,
SimpleTransitionFlag flag) {
if (!map->HasTransitionArray()) {
return TransitionArray::NewWith(map, name, target, flag);
}
int number_of_transitions = map->transitions()->number_of_transitions();
int new_size = number_of_transitions;
int insertion_index = map->transitions()->Search(*name);
if (insertion_index == kNotFound) ++new_size;
Handle<TransitionArray> result = Allocate(map->GetIsolate(), new_size);
// The map's transition array may grown smaller during the allocation above as
// it was weakly traversed, though it is guaranteed not to disappear. Trim the
// result copy if needed, and recompute variables.
ASSERT(map->HasTransitionArray());
DisallowHeapAllocation no_gc;
TransitionArray* array = map->transitions();
if (array->number_of_transitions() != number_of_transitions) {
ASSERT(array->number_of_transitions() < number_of_transitions);
number_of_transitions = array->number_of_transitions();
new_size = number_of_transitions;
insertion_index = array->Search(*name);
if (insertion_index == kNotFound) ++new_size;
result->Shrink(ToKeyIndex(new_size));
}
if (array->HasPrototypeTransitions()) {
result->SetPrototypeTransitions(array->GetPrototypeTransitions());
}
if (insertion_index != kNotFound) {
for (int i = 0; i < number_of_transitions; ++i) {
if (i != insertion_index) {
result->NoIncrementalWriteBarrierCopyFrom(array, i, i);
}
}
result->NoIncrementalWriteBarrierSet(insertion_index, *name, *target);
result->set_back_pointer_storage(array->back_pointer_storage());
return result;
}
insertion_index = 0;
for (; insertion_index < number_of_transitions; ++insertion_index) {
if (InsertionPointFound(array->GetKey(insertion_index), *name)) break;
result->NoIncrementalWriteBarrierCopyFrom(
array, insertion_index, insertion_index);
}
result->NoIncrementalWriteBarrierSet(insertion_index, *name, *target);
for (; insertion_index < number_of_transitions; ++insertion_index) {
result->NoIncrementalWriteBarrierCopyFrom(
array, insertion_index, insertion_index + 1);
}
result->set_back_pointer_storage(array->back_pointer_storage());
return result;
}
} } // namespace v8::internal
|
