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
|
// Copyright 2015 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_IDENTITY_MAP_H_
#define V8_IDENTITY_MAP_H_
#include "src/base/functional.h"
#include "src/handles.h"
namespace v8 {
namespace internal {
// Forward declarations.
class Heap;
class Zone;
// Base class of identity maps contains shared code for all template
// instantions.
class IdentityMapBase {
protected:
// Allow Tester to access internals, including changing the address of objects
// within the {keys_} array in order to simulate a moving GC.
friend class IdentityMapTester;
typedef void** RawEntry;
IdentityMapBase(Heap* heap, Zone* zone)
: heap_(heap),
zone_(zone),
gc_counter_(-1),
size_(0),
mask_(0),
keys_(nullptr),
values_(nullptr) {}
~IdentityMapBase();
RawEntry GetEntry(Object* key);
RawEntry FindEntry(Object* key);
void Clear();
private:
// Internal implementation should not be called directly by subclasses.
int LookupIndex(Object* address);
int InsertIndex(Object* address);
void Rehash();
void Resize();
RawEntry Lookup(Object* key);
RawEntry Insert(Object* key);
int Hash(Object* address);
base::hash<uintptr_t> hasher_;
Heap* heap_;
Zone* zone_;
int gc_counter_;
int size_;
int mask_;
Object** keys_;
void** values_;
};
// Implements an identity map from object addresses to a given value type {V}.
// The map is robust w.r.t. garbage collection by synchronization with the
// supplied {heap}.
// * Keys are treated as strong roots.
// * SMIs are valid keys, except SMI #0.
// * The value type {V} must be reinterpret_cast'able to {void*}
// * The value type {V} must not be a heap type.
template <typename V>
class IdentityMap : public IdentityMapBase {
public:
IdentityMap(Heap* heap, Zone* zone) : IdentityMapBase(heap, zone) {}
// Searches this map for the given key using the object's address
// as the identity, returning:
// found => a pointer to the storage location for the value
// not found => a pointer to a new storage location for the value
V* Get(Handle<Object> key) { return Get(*key); }
V* Get(Object* key) { return reinterpret_cast<V*>(GetEntry(key)); }
// Searches this map for the given key using the object's address
// as the identity, returning:
// found => a pointer to the storage location for the value
// not found => {nullptr}
V* Find(Handle<Object> key) { return Find(*key); }
V* Find(Object* key) { return reinterpret_cast<V*>(FindEntry(key)); }
// Set the value for the given key.
void Set(Handle<Object> key, V v) { Set(*key, v); }
void Set(Object* key, V v) { *(reinterpret_cast<V*>(GetEntry(key))) = v; }
// Removes all elements from the map.
void Clear() { IdentityMapBase::Clear(); }
};
} // namespace internal
} // namespace v8
#endif // V8_IDENTITY_MAP_H_
|
