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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
|
/*
* Copyright (C) 2011-2015 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.
*/
#ifndef DFGVariableAccessData_h
#define DFGVariableAccessData_h
#if ENABLE(DFG_JIT)
#include "DFGCommon.h"
#include "DFGDoubleFormatState.h"
#include "DFGFlushFormat.h"
#include "DFGFlushedAt.h"
#include "DFGNodeFlags.h"
#include "Operands.h"
#include "SpeculatedType.h"
#include "VirtualRegister.h"
#include <wtf/UnionFind.h>
#include <wtf/Vector.h>
namespace JSC { namespace DFG {
struct Node;
enum DoubleBallot { VoteValue, VoteDouble };
class VariableAccessData : public UnionFind<VariableAccessData> {
public:
VariableAccessData();
VariableAccessData(VirtualRegister local);
VirtualRegister local()
{
ASSERT(m_local == find()->m_local);
return m_local;
}
VirtualRegister& machineLocal()
{
ASSERT(find() == this);
return m_machineLocal;
}
bool mergeIsProfitableToUnbox(bool isProfitableToUnbox)
{
return checkAndSet(m_isProfitableToUnbox, m_isProfitableToUnbox || isProfitableToUnbox);
}
bool isProfitableToUnbox()
{
return m_isProfitableToUnbox;
}
bool mergeShouldNeverUnbox(bool shouldNeverUnbox);
// Returns true if it would be unsound to store the value in an unboxed fashion.
// If this returns false, it simply means that it is sound to unbox; it doesn't
// mean that we have actually done so.
bool shouldNeverUnbox()
{
return m_shouldNeverUnbox;
}
// Returns true if we should be unboxing the value provided that the predictions
// and double format vote say so. This may return false even if shouldNeverUnbox()
// returns false, since this incorporates heuristics of profitability.
bool shouldUnboxIfPossible()
{
return !shouldNeverUnbox() && isProfitableToUnbox();
}
bool mergeStructureCheckHoistingFailed(bool failed)
{
return checkAndSet(m_structureCheckHoistingFailed, m_structureCheckHoistingFailed || failed);
}
bool mergeCheckArrayHoistingFailed(bool failed)
{
return checkAndSet(m_checkArrayHoistingFailed, m_checkArrayHoistingFailed || failed);
}
bool structureCheckHoistingFailed()
{
return m_structureCheckHoistingFailed;
}
bool checkArrayHoistingFailed()
{
return m_checkArrayHoistingFailed;
}
bool mergeIsLoadedFrom(bool isLoadedFrom)
{
return checkAndSet(m_isLoadedFrom, m_isLoadedFrom || isLoadedFrom);
}
void setIsLoadedFrom(bool isLoadedFrom)
{
m_isLoadedFrom = isLoadedFrom;
}
bool isLoadedFrom()
{
return m_isLoadedFrom;
}
bool predict(SpeculatedType prediction);
SpeculatedType nonUnifiedPrediction()
{
return m_prediction;
}
SpeculatedType prediction()
{
return find()->m_prediction;
}
SpeculatedType argumentAwarePrediction()
{
return find()->m_argumentAwarePrediction;
}
bool mergeArgumentAwarePrediction(SpeculatedType prediction);
void clearVotes()
{
ASSERT(find() == this);
m_votes[0] = 0;
m_votes[1] = 0;
}
void vote(unsigned ballot, float weight = 1)
{
ASSERT(ballot < 2);
m_votes[ballot] += weight;
}
double voteRatio()
{
ASSERT(find() == this);
return static_cast<double>(m_votes[1]) / m_votes[0];
}
bool shouldUseDoubleFormatAccordingToVote();
DoubleFormatState doubleFormatState()
{
return find()->m_doubleFormatState;
}
bool shouldUseDoubleFormat()
{
ASSERT(isRoot());
bool doubleState = m_doubleFormatState == UsingDoubleFormat;
ASSERT(!(doubleState && shouldNeverUnbox()));
return doubleState && isProfitableToUnbox();
}
bool tallyVotesForShouldUseDoubleFormat();
bool mergeDoubleFormatState(DoubleFormatState);
bool makePredictionForDoubleFormat();
NodeFlags flags() const { return m_flags; }
bool mergeFlags(NodeFlags newFlags)
{
return checkAndSet(m_flags, m_flags | newFlags);
}
FlushFormat flushFormat();
bool couldRepresentInt52();
FlushedAt flushedAt()
{
return FlushedAt(flushFormat(), machineLocal());
}
private:
bool couldRepresentInt52Impl();
// This is slightly space-inefficient, since anything we're unified with
// will have the same operand and should have the same prediction. But
// putting them here simplifies the code, and we don't expect DFG space
// usage for variable access nodes do be significant.
VirtualRegister m_local;
VirtualRegister m_machineLocal;
SpeculatedType m_prediction;
SpeculatedType m_argumentAwarePrediction;
NodeFlags m_flags;
bool m_shouldNeverUnbox;
bool m_structureCheckHoistingFailed;
bool m_checkArrayHoistingFailed;
bool m_isProfitableToUnbox;
bool m_isLoadedFrom;
float m_votes[2]; // Used primarily for double voting but may be reused for other purposes.
DoubleFormatState m_doubleFormatState;
};
} } // namespace JSC::DFG
#endif // ENABLE(DFG_JIT)
#endif // DFGVariableAccessData_h
|
