1/*
2 * Copyright (C) 2008 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 "JSCast.h"
29#include "JSObject.h"
30#include "Structure.h"
31#include <wtf/StdLibExtras.h>
32#include <wtf/UniqueArray.h>
33
34namespace JSC {
35
36class LLIntOffsetsExtractor;
37class Structure;
38
39class StructureChain final : public JSCell {
40 friend class JIT;
41
42public:
43 typedef JSCell Base;
44 static const unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal;
45
46 static StructureChain* create(VM& vm, JSObject* head)
47 {
48 StructureChain* chain = new (NotNull, allocateCell<StructureChain>(vm.heap)) StructureChain(vm, vm.structureChainStructure.get());
49 chain->finishCreation(vm, head);
50 return chain;
51 }
52 WriteBarrier<Structure>* head() { return m_vector.get(); }
53 static void visitChildren(JSCell*, SlotVisitor&);
54
55 static Structure* createStructure(VM& vm, JSGlobalObject* globalObject, JSValue prototype)
56 {
57 return Structure::create(vm, globalObject, prototype, TypeInfo(CellType, StructureFlags), info());
58 }
59
60 DECLARE_INFO;
61
62 static const bool needsDestruction = true;
63 static void destroy(JSCell*);
64
65protected:
66 void finishCreation(VM& vm, JSObject* head)
67 {
68 Base::finishCreation(vm);
69
70 size_t size = 0;
71 for (JSObject* current = head; current; current = current->structure(vm)->storedPrototypeObject(current))
72 ++size;
73
74 auto vector = makeUniqueArray<WriteBarrier<Structure>>(size + 1);
75
76 size_t i = 0;
77 for (JSObject* current = head; current; current = current->structure(vm)->storedPrototypeObject(current))
78 vector[i++].set(vm, this, current->structure(vm));
79
80 vm.heap.mutatorFence();
81 m_vector = WTFMove(vector);
82 vm.heap.writeBarrier(this);
83 }
84
85private:
86 friend class LLIntOffsetsExtractor;
87
88 StructureChain(VM&, Structure*);
89 UniqueArray<WriteBarrier<Structure>> m_vector;
90};
91
92} // namespace JSC
93