1/*
2 * Copyright (C) 2018 Yusuke Suzuki <utatane.tea@gmail.com>.
3 * Copyright (C) 2018 Apple Inc. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#pragma once
28
29#include "CallLinkStatus.h"
30#include "CodeOrigin.h"
31#include "ConcurrentJSLock.h"
32#include "ICStatusMap.h"
33#include "InByIdVariant.h"
34#include "StubInfoSummary.h"
35
36namespace JSC {
37
38class AccessCase;
39class CodeBlock;
40class StructureStubInfo;
41
42class InByIdStatus {
43public:
44 enum State {
45 // It's uncached so we have no information.
46 NoInformation,
47 // It's cached for a simple access to a known object property with
48 // a possible structure chain and a possible specific value.
49 Simple,
50 // It's known to often take slow path.
51 TakesSlowPath,
52 };
53
54 InByIdStatus() = default;
55
56 InByIdStatus(State state, const InByIdVariant& variant = InByIdVariant())
57 : m_state(state)
58 {
59 ASSERT((state == Simple) == variant.isSet());
60 if (variant.isSet())
61 m_variants.append(variant);
62 }
63
64 explicit InByIdStatus(StubInfoSummary summary)
65 {
66 switch (summary) {
67 case StubInfoSummary::NoInformation:
68 m_state = NoInformation;
69 return;
70 case StubInfoSummary::Simple:
71 case StubInfoSummary::MakesCalls:
72 RELEASE_ASSERT_NOT_REACHED();
73 return;
74 case StubInfoSummary::TakesSlowPath:
75 case StubInfoSummary::TakesSlowPathAndMakesCalls:
76 m_state = TakesSlowPath;
77 return;
78 }
79 RELEASE_ASSERT_NOT_REACHED();
80 }
81
82 static InByIdStatus computeFor(CodeBlock*, ICStatusMap&, unsigned bytecodeIndex, UniquedStringImpl* uid);
83 static InByIdStatus computeFor(CodeBlock*, ICStatusMap&, unsigned bytecodeIndex, UniquedStringImpl* uid, ExitFlag);
84 static InByIdStatus computeFor(CodeBlock* baselineBlock, ICStatusMap& baselineMap, ICStatusContextStack& contextStack, CodeOrigin, UniquedStringImpl* uid);
85
86#if ENABLE(DFG_JIT)
87 static InByIdStatus computeForStubInfo(const ConcurrentJSLocker&, CodeBlock* baselineBlock, StructureStubInfo*, CodeOrigin, UniquedStringImpl* uid);
88#endif
89
90 State state() const { return m_state; }
91
92 bool isSet() const { return m_state != NoInformation; }
93 explicit operator bool() const { return isSet(); }
94 bool isSimple() const { return m_state == Simple; }
95
96 size_t numVariants() const { return m_variants.size(); }
97 const Vector<InByIdVariant, 1>& variants() const { return m_variants; }
98 const InByIdVariant& at(size_t index) const { return m_variants[index]; }
99 const InByIdVariant& operator[](size_t index) const { return at(index); }
100
101 bool takesSlowPath() const { return m_state == TakesSlowPath; }
102
103 void merge(const InByIdStatus&);
104
105 // Attempts to reduce the set of variants to fit the given structure set. This may be approximate.
106 void filter(const StructureSet&);
107
108 void markIfCheap(SlotVisitor&);
109 bool finalize(VM&);
110
111 void dump(PrintStream&) const;
112
113private:
114#if ENABLE(DFG_JIT)
115 static InByIdStatus computeForStubInfoWithoutExitSiteFeedback(const ConcurrentJSLocker&, StructureStubInfo*, UniquedStringImpl* uid);
116#endif
117 bool appendVariant(const InByIdVariant&);
118
119 State m_state { NoInformation };
120 Vector<InByIdVariant, 1> m_variants;
121};
122
123} // namespace JSC
124