1/*
2 * Copyright (C) 2013-2019 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 "IndexingType.h"
29#include "JSTypeInfo.h"
30#include "PrototypeKey.h"
31#include "WeakGCMap.h"
32#include <wtf/Lock.h>
33#include <wtf/TriState.h>
34
35namespace JSC {
36
37class FunctionExecutable;
38class JSGlobalObject;
39class JSObject;
40class Structure;
41class VM;
42
43// Tracks the canonical structure an object should be allocated with when inheriting from a given prototype.
44class StructureCache {
45public:
46 explicit StructureCache(VM& vm)
47 : m_structures(vm)
48 {
49 }
50
51 void clear() { m_structures.clear(); }
52
53 JS_EXPORT_PRIVATE Structure* emptyObjectStructureForPrototype(JSGlobalObject*, JSObject*, unsigned inlineCapacity, bool makePolyProtoStructure = false, FunctionExecutable* = nullptr);
54 JS_EXPORT_PRIVATE Structure* emptyStructureForPrototypeFromBaseStructure(JSGlobalObject*, JSObject*, Structure*);
55 JS_EXPORT_PRIVATE Structure* emptyObjectStructureConcurrently(JSGlobalObject*, JSObject* prototype, unsigned inlineCapacity);
56
57private:
58 Structure* createEmptyStructure(JSGlobalObject*, JSObject* prototype, const TypeInfo&, const ClassInfo*, IndexingType, unsigned inlineCapacity, bool makePolyProtoStructure, FunctionExecutable*);
59
60 using StructureMap = WeakGCMap<PrototypeKey, Structure>;
61 StructureMap m_structures;
62 Lock m_lock;
63};
64
65} // namespace JSC
66