1/*
2 * Copyright (C) 2013, 2014, 2016 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#if ENABLE(DFG_JIT)
29
30#include "DFGCommon.h"
31#include "DFGFrozenValue.h"
32#include "GPRInfo.h"
33#include <wtf/text/StringImpl.h>
34
35namespace JSC {
36
37class CCallHelpers;
38
39namespace DFG {
40
41class Graph;
42
43// Represents either a JSValue, or for JSValues that require allocation in the heap,
44// it tells you everything you'd need to know in order to allocate it.
45
46class LazyJSValue {
47public:
48 enum LazinessKind {
49 KnownValue,
50 SingleCharacterString,
51 KnownStringImpl,
52 NewStringImpl
53 };
54
55 LazyJSValue(FrozenValue* value = FrozenValue::emptySingleton())
56 : m_kind(KnownValue)
57 {
58 u.value = value;
59 }
60
61 static LazyJSValue singleCharacterString(UChar character)
62 {
63 LazyJSValue result;
64 result.m_kind = SingleCharacterString;
65 result.u.character = character;
66 return result;
67 }
68
69 static LazyJSValue knownStringImpl(StringImpl* string)
70 {
71 LazyJSValue result;
72 result.m_kind = KnownStringImpl;
73 result.u.stringImpl = string;
74 return result;
75 }
76
77 static LazyJSValue newString(Graph&, const String&);
78
79 LazinessKind kind() const { return m_kind; }
80
81 FrozenValue* tryGetValue(Graph&) const
82 {
83 if (m_kind == KnownValue)
84 return value();
85 return nullptr;
86 }
87
88 JSValue getValue(VM&) const;
89
90 FrozenValue* value() const
91 {
92 ASSERT(m_kind == KnownValue);
93 return u.value;
94 }
95
96 UChar character() const
97 {
98 ASSERT(m_kind == SingleCharacterString);
99 return u.character;
100 }
101
102 const StringImpl* tryGetStringImpl(VM&) const;
103
104 String tryGetString(Graph&) const;
105
106 StringImpl* stringImpl() const
107 {
108 ASSERT(m_kind == KnownStringImpl || m_kind == NewStringImpl);
109 return u.stringImpl;
110 }
111
112 TriState strictEqual(const LazyJSValue& other) const;
113
114 uintptr_t switchLookupValue(SwitchKind) const;
115
116 void emit(CCallHelpers&, JSValueRegs) const;
117
118 void dump(PrintStream&) const;
119 void dumpInContext(PrintStream&, DumpContext*) const;
120
121private:
122 union {
123 FrozenValue* value;
124 UChar character;
125 StringImpl* stringImpl;
126 } u;
127 LazinessKind m_kind;
128};
129
130} } // namespace JSC::DFG
131
132#endif // ENABLE(DFG_JIT)
133