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
|
/*
* Copyright (C) 2014-2016 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.
*/
#include "config.h"
#include "DFGMayExit.h"
#if ENABLE(DFG_JIT)
#include "DFGAtTailAbstractState.h"
#include "DFGGraph.h"
#include "DFGNode.h"
#include "DFGNullAbstractState.h"
#include "Operations.h"
namespace JSC { namespace DFG {
namespace {
template<typename StateType>
ExitMode mayExitImpl(Graph& graph, Node* node, StateType& state)
{
ExitMode result = DoesNotExit;
switch (node->op()) {
// This is a carefully curated list of nodes that definitely do not exit. We try to be very
// conservative when maintaining this list, because adding new node types to it doesn't
// generally make things a lot better but it might introduce subtle bugs.
case SetArgument:
case JSConstant:
case DoubleConstant:
case LazyJSConstant:
case Int52Constant:
case MovHint:
case SetLocal:
case Flush:
case Phantom:
case Check:
case Identity:
case GetLocal:
case LoopHint:
case Phi:
case Upsilon:
case ZombieHint:
case ExitOK:
case BottomValue:
case PutHint:
case PhantomNewObject:
case PutStack:
case KillStack:
case GetStack:
case GetCallee:
case GetArgumentCountIncludingThis:
case GetRestLength:
case GetScope:
case PhantomLocal:
case CountExecution:
case Jump:
case Branch:
case Unreachable:
case DoubleRep:
case Int52Rep:
case ValueRep:
case ExtractOSREntryLocal:
case LogicalNot:
case NotifyWrite:
case PutStructure:
case StoreBarrier:
case FencedStoreBarrier:
case PutByOffset:
case PutClosureVar:
case RecordRegExpCachedResult:
case NukeStructureAndSetButterfly:
break;
case StrCat:
case Call:
case Construct:
case CallVarargs:
case CallEval:
case ConstructVarargs:
case CallForwardVarargs:
case ConstructForwardVarargs:
case CreateActivation:
case MaterializeCreateActivation:
case MaterializeNewObject:
case NewFunction:
case NewGeneratorFunction:
case NewAsyncFunction:
case NewStringObject:
case ToNumber:
result = ExitsForExceptions;
break;
default:
// If in doubt, return true.
return Exits;
}
graph.doToChildren(
node,
[&] (Edge& edge) {
if (state) {
// Ignore the Check flag on the edge. This is important because that flag answers
// the question: "would this edge have had a check if it executed wherever it
// currently resides in control flow?" But when a state is passed, we want to ask a
// different question: "would this edge have a check if it executed wherever this
// state is?" Using the Check flag for this purpose wouldn't even be conservatively
// correct. It would be wrong in both directions.
if (mayHaveTypeCheck(edge.useKind())
&& (state.forNode(edge).m_type & ~typeFilterFor(edge.useKind()))) {
result = Exits;
return;
}
} else {
// FIXME: Maybe this should call mayHaveTypeCheck(edge.useKind()) instead.
// https://bugs.webkit.org/show_bug.cgi?id=148545
if (edge.willHaveCheck()) {
result = Exits;
return;
}
}
switch (edge.useKind()) {
// These are shady because nodes that have these use kinds will typically exit for
// unrelated reasons. For example CompareEq doesn't usually exit, but if it uses
// ObjectUse then it will.
case ObjectUse:
case ObjectOrOtherUse:
result = Exits;
break;
// These are shady because they check the structure even if the type of the child node
// passes the StringObject type filter.
case StringObjectUse:
case StringOrStringObjectUse:
result = Exits;
break;
default:
break;
}
});
return result;
}
} // anonymous namespace
ExitMode mayExit(Graph& graph, Node* node)
{
NullAbstractState state;
return mayExitImpl(graph, node, state);
}
ExitMode mayExit(Graph& graph, Node* node, AtTailAbstractState& state)
{
return mayExitImpl(graph, node, state);
}
} } // namespace JSC::DFG
namespace WTF {
using namespace JSC::DFG;
void printInternal(PrintStream& out, ExitMode mode)
{
switch (mode) {
case DoesNotExit:
out.print("DoesNotExit");
return;
case ExitsForExceptions:
out.print("ExitsForExceptions");
return;
case Exits:
out.print("Exits");
return;
}
RELEASE_ASSERT_NOT_REACHED();
}
} // namespace WTF
#endif // ENABLE(DFG_JIT)
|
