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 "DisallowScope.h"
29#include "Heap.h"
30#include <wtf/ThreadSpecific.h>
31
32namespace JSC {
33
34class DeferGC {
35 WTF_MAKE_NONCOPYABLE(DeferGC);
36 WTF_FORBID_HEAP_ALLOCATION;
37public:
38 DeferGC(Heap& heap)
39 : m_heap(heap)
40 {
41 m_heap.incrementDeferralDepth();
42 }
43
44 ~DeferGC()
45 {
46 if (validateDFGDoesGC)
47 RELEASE_ASSERT(m_heap.expectDoesGC());
48 m_heap.decrementDeferralDepthAndGCIfNeeded();
49 }
50
51private:
52 Heap& m_heap;
53};
54
55class DeferGCForAWhile {
56 WTF_MAKE_NONCOPYABLE(DeferGCForAWhile);
57 WTF_FORBID_HEAP_ALLOCATION;
58public:
59 DeferGCForAWhile(Heap& heap)
60 : m_heap(heap)
61 {
62 m_heap.incrementDeferralDepth();
63 }
64
65 ~DeferGCForAWhile()
66 {
67 m_heap.decrementDeferralDepth();
68 }
69
70private:
71 Heap& m_heap;
72};
73
74class DisallowGC : public DisallowScope<DisallowGC> {
75 WTF_MAKE_NONCOPYABLE(DisallowGC);
76 WTF_FORBID_HEAP_ALLOCATION;
77 typedef DisallowScope<DisallowGC> Base;
78public:
79#ifdef NDEBUG
80
81 ALWAYS_INLINE DisallowGC(bool = false) { }
82 ALWAYS_INLINE static void initialize() { }
83
84#else // not NDEBUG
85
86 DisallowGC(bool enabled = true)
87 : Base(enabled)
88 { }
89
90 static void initialize()
91 {
92 WTF::threadSpecificKeyCreate(&s_scopeReentryCount, 0);
93 }
94
95private:
96 static uintptr_t scopeReentryCount()
97 {
98 return reinterpret_cast<uintptr_t>(WTF::threadSpecificGet(s_scopeReentryCount));
99 }
100 static void setScopeReentryCount(uintptr_t value)
101 {
102 WTF::threadSpecificSet(s_scopeReentryCount, reinterpret_cast<void*>(value));
103 }
104
105 JS_EXPORT_PRIVATE static WTF::ThreadSpecificKey s_scopeReentryCount;
106
107#endif // NDEBUG
108
109 friend class DisallowScope<DisallowGC>;
110};
111
112} // namespace JSC
113