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 2017 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_OBJECTS_VISITORS_H_
#define V8_OBJECTS_VISITORS_H_
#include "src/common/globals.h"
#include "src/objects/code.h"
#include "src/objects/compressed-slots.h"
#include "src/objects/foreign.h"
#include "src/objects/slots.h"
namespace v8 {
namespace internal {
class CodeDataContainer;
#define ROOT_ID_LIST(V) \
V(kStringTable, "(Internalized strings)") \
V(kExternalStringsTable, "(External strings)") \
V(kReadOnlyRootList, "(Read-only roots)") \
V(kStrongRootList, "(Strong roots)") \
V(kSmiRootList, "(Smi roots)") \
V(kBootstrapper, "(Bootstrapper)") \
V(kTop, "(Isolate)") \
V(kRelocatable, "(Relocatable)") \
V(kDebug, "(Debugger)") \
V(kCompilationCache, "(Compilation cache)") \
V(kHandleScope, "(Handle scope)") \
V(kBuiltins, "(Builtins)") \
V(kGlobalHandles, "(Global handles)") \
V(kEternalHandles, "(Eternal handles)") \
V(kThreadManager, "(Thread manager)") \
V(kStrongRoots, "(Strong roots)") \
V(kExtensions, "(Extensions)") \
V(kCodeFlusher, "(Code flusher)") \
V(kPartialSnapshotCache, "(Partial snapshot cache)") \
V(kReadOnlyObjectCache, "(Read-only object cache)") \
V(kWeakCollections, "(Weak collections)") \
V(kWrapperTracing, "(Wrapper tracing)") \
V(kUnknown, "(Unknown)")
class VisitorSynchronization : public AllStatic {
public:
#define DECLARE_ENUM(enum_item, ignore) enum_item,
enum SyncTag { ROOT_ID_LIST(DECLARE_ENUM) kNumberOfSyncTags };
#undef DECLARE_ENUM
};
enum class Root {
#define DECLARE_ENUM(enum_item, ignore) enum_item,
ROOT_ID_LIST(DECLARE_ENUM)
#undef DECLARE_ENUM
kNumberOfRoots
};
// Abstract base class for visiting, and optionally modifying, the
// pointers contained in roots. Used in GC and serialization/deserialization.
class RootVisitor {
public:
virtual ~RootVisitor() = default;
// Visits a contiguous arrays of pointers in the half-open range
// [start, end). Any or all of the values may be modified on return.
virtual void VisitRootPointers(Root root, const char* description,
FullObjectSlot start, FullObjectSlot end) = 0;
// Handy shorthand for visiting a single pointer.
virtual void VisitRootPointer(Root root, const char* description,
FullObjectSlot p) {
VisitRootPointers(root, description, p, p + 1);
}
// Intended for serialization/deserialization checking: insert, or
// check for the presence of, a tag at this position in the stream.
// Also used for marking up GC roots in heap snapshots.
// TODO(ulan): Remove this.
virtual void Synchronize(VisitorSynchronization::SyncTag tag) {}
static const char* RootName(Root root);
};
class RelocIterator;
// Abstract base class for visiting, and optionally modifying, the
// pointers contained in Objects. Used in GC and serialization/deserialization.
class ObjectVisitor {
public:
virtual ~ObjectVisitor() = default;
// Visits a contiguous arrays of pointers in the half-open range
// [start, end). Any or all of the values may be modified on return.
virtual void VisitPointers(HeapObject host, ObjectSlot start,
ObjectSlot end) = 0;
virtual void VisitPointers(HeapObject host, MaybeObjectSlot start,
MaybeObjectSlot end) = 0;
// Custom weak pointers must be ignored by the GC but not other
// visitors. They're used for e.g., lists that are recreated after GC. The
// default implementation treats them as strong pointers. Visitors who want to
// ignore them must override this function with empty.
virtual void VisitCustomWeakPointers(HeapObject host, ObjectSlot start,
ObjectSlot end) {
VisitPointers(host, start, end);
}
// Handy shorthand for visiting a single pointer.
virtual void VisitPointer(HeapObject host, ObjectSlot p) {
VisitPointers(host, p, p + 1);
}
virtual void VisitPointer(HeapObject host, MaybeObjectSlot p) {
VisitPointers(host, p, p + 1);
}
virtual void VisitCustomWeakPointer(HeapObject host, ObjectSlot p) {
VisitCustomWeakPointers(host, p, p + 1);
}
virtual void VisitEphemeron(HeapObject host, int index, ObjectSlot key,
ObjectSlot value) {
VisitPointer(host, key);
VisitPointer(host, value);
}
// To allow lazy clearing of inline caches the visitor has
// a rich interface for iterating over Code objects ...
// Visits a code target in the instruction stream.
virtual void VisitCodeTarget(Code host, RelocInfo* rinfo) = 0;
// Visit pointer embedded into a code object.
virtual void VisitEmbeddedPointer(Code host, RelocInfo* rinfo) = 0;
// Visits a runtime entry in the instruction stream.
virtual void VisitRuntimeEntry(Code host, RelocInfo* rinfo) {}
// Visits an external reference embedded into a code object.
virtual void VisitExternalReference(Code host, RelocInfo* rinfo) {}
// Visits an external reference.
virtual void VisitExternalReference(Foreign host, Address* p) {}
// Visits an (encoded) internal reference.
virtual void VisitInternalReference(Code host, RelocInfo* rinfo) {}
// Visits an off-heap target in the instruction stream.
virtual void VisitOffHeapTarget(Code host, RelocInfo* rinfo) {}
// Visits the relocation info using the given iterator.
virtual void VisitRelocInfo(RelocIterator* it);
};
} // namespace internal
} // namespace v8
#endif // V8_OBJECTS_VISITORS_H_
|