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
|
/*
* Copyright (C) 2012, 2013 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 "IndexingType.h"
#include "JSArray.h"
namespace JSC {
class ArrayAllocationProfile {
public:
ArrayAllocationProfile()
{
initializeIndexingMode(ArrayWithUndecided);
}
ArrayAllocationProfile(IndexingType recommendedIndexingMode)
{
initializeIndexingMode(recommendedIndexingMode);
}
IndexingType selectIndexingTypeConcurrently()
{
return current().indexingType();
}
IndexingType selectIndexingType()
{
ASSERT(!isCompilationThread());
JSArray* lastArray = m_storage.pointer();
if (lastArray && UNLIKELY(lastArray->indexingType() != current().indexingType()))
updateProfile();
return current().indexingType();
}
// vector length hint becomes [0, BASE_CONTIGUOUS_VECTOR_LEN_MAX].
unsigned vectorLengthHintConcurrently()
{
return current().vectorLength();
}
unsigned vectorLengthHint()
{
ASSERT(!isCompilationThread());
JSArray* lastArray = m_storage.pointer();
unsigned largestSeenVectorLength = current().vectorLength();
if (lastArray && (largestSeenVectorLength != BASE_CONTIGUOUS_VECTOR_LEN_MAX) && UNLIKELY(lastArray->getVectorLength() > largestSeenVectorLength))
updateProfile();
return current().vectorLength();
}
JSArray* updateLastAllocation(JSArray* lastArray)
{
ASSERT(!isCompilationThread());
m_storage.setPointer(lastArray);
return lastArray;
}
JS_EXPORT_PRIVATE void updateProfile();
static IndexingType selectIndexingTypeFor(ArrayAllocationProfile* profile)
{
if (!profile)
return ArrayWithUndecided;
return profile->selectIndexingType();
}
static JSArray* updateLastAllocationFor(ArrayAllocationProfile* profile, JSArray* lastArray)
{
ASSERT(!isCompilationThread());
if (profile)
profile->updateLastAllocation(lastArray);
return lastArray;
}
void initializeIndexingMode(IndexingType recommendedIndexingMode)
{
m_storage.setType(current().withIndexingType(recommendedIndexingMode));
}
private:
struct IndexingTypeAndVectorLength {
static_assert(sizeof(IndexingType) <= sizeof(uint8_t));
static_assert(BASE_CONTIGUOUS_VECTOR_LEN_MAX <= UINT8_MAX);
// The format is: (IndexingType << 8) | VectorLength
static constexpr uint16_t vectorLengthMask = static_cast<uint8_t>(-1);
static constexpr uint16_t indexingTypeShift = 8;
public:
IndexingTypeAndVectorLength()
: m_bits(0)
{
}
IndexingTypeAndVectorLength(uint16_t bits)
: m_bits(bits)
{
}
IndexingTypeAndVectorLength(IndexingType indexingType, unsigned vectorLength)
: m_bits((indexingType << indexingTypeShift) | vectorLength)
{
ASSERT(vectorLength <= BASE_CONTIGUOUS_VECTOR_LEN_MAX);
}
operator uint16_t() const { return m_bits; }
IndexingType indexingType() const { return m_bits >> indexingTypeShift; }
unsigned vectorLength() const { return m_bits & vectorLengthMask; }
IndexingTypeAndVectorLength withIndexingType(IndexingType indexingType) WARN_UNUSED_RETURN
{
return IndexingTypeAndVectorLength(indexingType, vectorLength());
}
private:
uint16_t m_bits;
};
IndexingTypeAndVectorLength current() const { return m_storage.type(); }
using Storage = CompactPointerTuple<JSArray*, uint16_t>;
Storage m_storage;
};
} // namespace JSC
|
