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 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.
#ifndef V8_HEAP_INCREMENTAL_MARKING_INL_H_
#define V8_HEAP_INCREMENTAL_MARKING_INL_H_
#include "src/heap/incremental-marking.h"
#include "src/execution/isolate.h"
#include "src/heap/mark-compact-inl.h"
#include "src/objects/maybe-object.h"
#include "src/objects/objects-inl.h"
namespace v8 {
namespace internal {
void IncrementalMarking::TransferColor(HeapObject from, HeapObject to) {
if (atomic_marking_state()->IsBlack(to)) {
DCHECK(black_allocation());
return;
}
DCHECK(atomic_marking_state()->IsWhite(to));
if (atomic_marking_state()->IsGrey(from)) {
bool success = atomic_marking_state()->WhiteToGrey(to);
DCHECK(success);
USE(success);
} else if (atomic_marking_state()->IsBlack(from)) {
bool success = atomic_marking_state()->WhiteToBlack(to);
DCHECK(success);
USE(success);
}
}
bool IncrementalMarking::BaseRecordWrite(HeapObject obj, HeapObject value) {
DCHECK(!marking_state()->IsImpossible(value));
DCHECK(!marking_state()->IsImpossible(obj));
// The write barrier stub generated with V8_CONCURRENT_MARKING does not
// check the color of the source object.
const bool need_recording =
V8_CONCURRENT_MARKING_BOOL || marking_state()->IsBlack(obj);
if (need_recording && WhiteToGreyAndPush(value)) {
RestartIfNotMarking();
}
return is_compacting_ && need_recording;
}
template <typename TSlot>
void IncrementalMarking::RecordWrite(HeapObject obj, TSlot slot,
typename TSlot::TObject value) {
static_assert(std::is_same<TSlot, ObjectSlot>::value ||
std::is_same<TSlot, MaybeObjectSlot>::value,
"Only ObjectSlot and MaybeObjectSlot are expected here");
DCHECK_NE(slot.address(), kNullAddress);
DCHECK_IMPLIES(!TSlot::kCanBeWeak, !HAS_WEAK_HEAP_OBJECT_TAG((*slot).ptr()));
DCHECK_IMPLIES(!TSlot::kCanBeWeak, !HAS_WEAK_HEAP_OBJECT_TAG(value.ptr()));
// When writing a weak reference, treat it as strong for the purposes of the
// marking barrier.
HeapObject value_heap_object;
if (IsMarking() && value.GetHeapObject(&value_heap_object)) {
RecordWriteSlow(obj, HeapObjectSlot(slot), value_heap_object);
}
}
bool IncrementalMarking::WhiteToGreyAndPush(HeapObject obj) {
if (marking_state()->WhiteToGrey(obj)) {
marking_worklist()->Push(obj);
return true;
}
return false;
}
void IncrementalMarking::RestartIfNotMarking() {
if (state_ == COMPLETE) {
state_ = MARKING;
if (FLAG_trace_incremental_marking) {
heap()->isolate()->PrintWithTimestamp(
"[IncrementalMarking] Restarting (new grey objects)\n");
}
}
}
} // namespace internal
} // namespace v8
#endif // V8_HEAP_INCREMENTAL_MARKING_INL_H_
|
