1/*
2 * Copyright (C) 2012-2018 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "CallLinkStatus.h"
29#include "CodeOrigin.h"
30#include "ConcurrentJSLock.h"
31#include "ExitFlag.h"
32#include "GetByIdVariant.h"
33#include "ICStatusMap.h"
34#include "ScopeOffset.h"
35#include "StubInfoSummary.h"
36
37namespace JSC {
38
39class AccessCase;
40class CodeBlock;
41class JSModuleEnvironment;
42class JSModuleNamespaceObject;
43class ModuleNamespaceAccessCase;
44class StructureStubInfo;
45
46class GetByStatus {
47 WTF_MAKE_FAST_ALLOCATED;
48public:
49 enum State : uint8_t {
50 // It's uncached so we have no information.
51 NoInformation,
52 // It's cached for a simple access to a known object property with
53 // a possible structure chain and a possible specific value.
54 Simple,
55 // It's cached for a custom accessor with a possible structure chain.
56 Custom,
57 // It's cached for an access to a module namespace object's binding.
58 ModuleNamespace,
59 // It will likely take the slow path.
60 LikelyTakesSlowPath,
61 // It's known to take slow path. We also observed that the slow path was taken on StructureStubInfo.
62 ObservedTakesSlowPath,
63 // It will likely take the slow path and will make calls.
64 MakesCalls,
65 // It known to take paths that make calls. We also observed that the slow path was taken on StructureStubInfo.
66 ObservedSlowPathAndMakesCalls ,
67 };
68
69 enum class TrackIdentifiers : uint8_t {
70 No, // Used for get_by_id
71 Yes, // Used for get_by_val
72 };
73
74 GetByStatus()
75 : m_state(NoInformation)
76 {
77 }
78
79 explicit GetByStatus(State state)
80 : m_state(state)
81 {
82 ASSERT(state == NoInformation || state == LikelyTakesSlowPath || state == ObservedTakesSlowPath || state == MakesCalls || state == ObservedSlowPathAndMakesCalls);
83 }
84
85 explicit GetByStatus(StubInfoSummary, StructureStubInfo&);
86
87 GetByStatus(
88 State state, bool wasSeenInJIT)
89 : m_state(state)
90 , m_wasSeenInJIT(wasSeenInJIT)
91 {
92 }
93
94 static GetByStatus computeFor(CodeBlock* baselineBlock, ICStatusMap& baselineMap, ICStatusContextStack& dfgContextStack, CodeOrigin, TrackIdentifiers);
95 static GetByStatus computeFor(const StructureSet&, UniquedStringImpl*);
96
97 State state() const { return m_state; }
98
99 bool isSet() const { return m_state != NoInformation; }
100 explicit operator bool() const { return isSet(); }
101 bool isSimple() const { return m_state == Simple; }
102 bool isCustom() const { return m_state == Custom; }
103 bool isModuleNamespace() const { return m_state == ModuleNamespace; }
104
105 size_t numVariants() const { return m_variants.size(); }
106 const Vector<GetByIdVariant, 1>& variants() const { return m_variants; }
107 const GetByIdVariant& at(size_t index) const { return m_variants[index]; }
108 const GetByIdVariant& operator[](size_t index) const { return at(index); }
109
110 bool takesSlowPath() const { return m_state == LikelyTakesSlowPath || m_state == ObservedTakesSlowPath || m_state == MakesCalls || m_state == ObservedSlowPathAndMakesCalls || m_state == Custom || m_state == ModuleNamespace; }
111 bool observedStructureStubInfoSlowPath() const { return m_state == ObservedTakesSlowPath || m_state == ObservedSlowPathAndMakesCalls; }
112 bool makesCalls() const;
113
114 GetByStatus slowVersion() const;
115
116 bool wasSeenInJIT() const { return m_wasSeenInJIT; }
117
118 // Attempts to reduce the set of variants to fit the given structure set. This may be approximate.
119 void filter(const StructureSet&);
120
121 JSModuleNamespaceObject* moduleNamespaceObject() const { return m_moduleNamespaceData->m_moduleNamespaceObject; }
122 JSModuleEnvironment* moduleEnvironment() const { return m_moduleNamespaceData->m_moduleEnvironment; }
123 ScopeOffset scopeOffset() const { return m_moduleNamespaceData->m_scopeOffset; }
124
125 void markIfCheap(SlotVisitor&);
126 bool finalize(VM&); // Return true if this gets to live.
127
128 bool appendVariant(const GetByIdVariant&);
129
130 void dump(PrintStream&) const;
131
132 Box<Identifier> singleIdentifier() const;
133
134private:
135 void merge(const GetByStatus&);
136
137#if ENABLE(JIT)
138 GetByStatus(const ModuleNamespaceAccessCase&);
139 static GetByStatus computeForStubInfoWithoutExitSiteFeedback(
140 const ConcurrentJSLocker&, CodeBlock* profiledBlock, StructureStubInfo*, CallLinkStatus::ExitSiteData, TrackIdentifiers);
141#endif
142 static GetByStatus computeFromLLInt(CodeBlock*, BytecodeIndex, TrackIdentifiers);
143 static GetByStatus computeFor(CodeBlock*, ICStatusMap&, BytecodeIndex, ExitFlag, CallLinkStatus::ExitSiteData, TrackIdentifiers);
144
145 struct ModuleNamespaceData {
146 JSModuleNamespaceObject* m_moduleNamespaceObject { nullptr };
147 JSModuleEnvironment* m_moduleEnvironment { nullptr };
148 ScopeOffset m_scopeOffset { };
149 Box<Identifier> m_identifier;
150 };
151
152 Vector<GetByIdVariant, 1> m_variants;
153 Box<ModuleNamespaceData> m_moduleNamespaceData;
154 State m_state;
155 bool m_wasSeenInJIT { false };
156};
157
158} // namespace JSC
159