Repository navigation
Expand file tree
/
Copy pathArrayStorage.h
More file actions
141 lines (113 loc) · 6.28 KB
/
Copy pathArrayStorage.h
File metadata and controls
141 lines (113 loc) · 6.28 KB
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
/*
* Copyright (C) 2012-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <JavaScriptCore/Butterfly.h>
#include <JavaScriptCore/IndexingHeader.h>
#include <JavaScriptCore/MarkedSpace.h>
#include <JavaScriptCore/SparseArrayValueMap.h>
#include <JavaScriptCore/Structure.h>
#include <JavaScriptCore/WriteBarrier.h>
#include <wtf/Noncopyable.h>
namespace JSC {
// This struct holds the actual data values of an array. A JSArray object points to its contained ArrayStorage
// struct by pointing to m_vector. To access the contained ArrayStorage struct, use the getStorage() and
// setStorage() methods. It is important to note that there may be space before the ArrayStorage that
// is used to quick unshift / shift operation. The actual allocated pointer is available by using:
// getStorage() - m_indexBias * sizeof(JSValue)
// All slots in ArrayStorage (slots from 0 to vectorLength) are expected to be initialized to a JSValue or,
// for hole slots, JSValue().
struct ArrayStorage {
WTF_MAKE_NONCOPYABLE(ArrayStorage);
private:
ArrayStorage() { } // Not directly instantiable. Can only be created as part of a Butterfly.
public:
static ArrayStorage* from(Butterfly* butterfly) { return reinterpret_cast_ptr<ArrayStorage*>(butterfly); }
static ArrayStorage* from(IndexingHeader* indexingHeader) { return indexingHeader->arrayStorage(); }
Butterfly* butterfly() { return reinterpret_cast<Butterfly*>(this); }
IndexingHeader* indexingHeader() { return IndexingHeader::from(this); }
const IndexingHeader* indexingHeader() const { return IndexingHeader::from(this); }
// We steal two fields from the indexing header: vectorLength and length.
unsigned length() const { return indexingHeader()->publicLength(); }
void setLength(unsigned length) { indexingHeader()->setPublicLength(length); }
unsigned vectorLength() const { return indexingHeader()->vectorLength(); }
void setVectorLength(unsigned length) { indexingHeader()->setVectorLength(length); }
ALWAYS_INLINE void copyHeaderFromDuringGC(const ArrayStorage& other)
{
m_sparseMap.copyFrom(other.m_sparseMap);
m_indexBias = other.m_indexBias;
m_numValuesInVector = other.m_numValuesInVector;
}
bool hasHoles() const
{
return m_numValuesInVector != length();
}
bool inSparseMode()
{
return m_sparseMap && m_sparseMap->sparseMode();
}
ContiguousJSValues vector() { return ContiguousJSValues(m_vector, vectorLength()); }
static constexpr ptrdiff_t lengthOffset() { return Butterfly::offsetOfPublicLength(); }
static constexpr ptrdiff_t vectorLengthOffset() { return Butterfly::offsetOfVectorLength(); }
static constexpr ptrdiff_t numValuesInVectorOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_numValuesInVector); }
static constexpr ptrdiff_t vectorOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_vector); }
static constexpr ptrdiff_t indexBiasOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_indexBias); }
static constexpr ptrdiff_t sparseMapOffset() { return OBJECT_OFFSETOF(ArrayStorage, m_sparseMap); }
static size_t sizeFor(unsigned vectorLength)
{
return ArrayStorage::vectorOffset() + vectorLength * sizeof(WriteBarrier<Unknown>);
}
static size_t totalSizeFor(unsigned indexBias, size_t propertyCapacity, unsigned vectorLength)
{
return Butterfly::totalSize(indexBias, propertyCapacity, true, sizeFor(vectorLength));
}
size_t totalSize(size_t propertyCapacity) const
{
return totalSizeFor(m_indexBias, propertyCapacity, vectorLength());
}
inline size_t totalSize(Structure*) const;
static unsigned availableVectorLength(unsigned indexBias, size_t propertyCapacity, unsigned vectorLength)
{
size_t cellSize = MarkedSpace::optimalSizeFor(totalSizeFor(indexBias, propertyCapacity, vectorLength));
vectorLength = (cellSize - totalSizeFor(indexBias, propertyCapacity, 0)) / sizeof(WriteBarrier<Unknown>);
return vectorLength;
}
inline static unsigned availableVectorLength(unsigned indexBias, Structure*, unsigned vectorLength);
inline unsigned availableVectorLength(size_t propertyCapacity, unsigned vectorLength);
inline unsigned availableVectorLength(Structure*, unsigned vectorLength);
inline static unsigned optimalVectorLength(unsigned indexBias, size_t propertyCapacity, unsigned vectorLength);
inline static unsigned optimalVectorLength(unsigned indexBias, Structure*, unsigned vectorLength);
inline unsigned optimalVectorLength(size_t propertyCapacity, unsigned vectorLength);
inline unsigned optimalVectorLength(Structure*, unsigned vectorLength);
WriteBarrier<SparseArrayValueMap> m_sparseMap;
unsigned m_indexBias;
unsigned m_numValuesInVector;
#if !CPU(ADDRESS64)
// Keep the JSValue vector 8-byte aligned relative to the butterfly base so the
// m_indexBias unshift math (getStorage() - m_indexBias * sizeof(JSValue)) stays aligned.
uintptr_t m_padding;
#endif
WriteBarrier<Unknown> m_vector[1];
};
} // namespace JSC