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/NeverDestroyed.h>
31#include <wtf/ThreadSpecific.h>
32
33namespace JSC {
34
35class DeferGC {
36 WTF_MAKE_NONCOPYABLE(DeferGC);
37 WTF_FORBID_HEAP_ALLOCATION;
38public:
39 DeferGC(Heap& heap)
40 : m_heap(heap)
41 {
42 m_heap.incrementDeferralDepth();
43 }
44
45 ~DeferGC()
46 {
47 if (validateDFGDoesGC)
48 RELEASE_ASSERT(m_heap.expectDoesGC());
49 m_heap.decrementDeferralDepthAndGCIfNeeded();
50 }
51
52private:
53 Heap& m_heap;
54};
55
56class DeferGCForAWhile {
57 WTF_MAKE_NONCOPYABLE(DeferGCForAWhile);
58 WTF_FORBID_HEAP_ALLOCATION;
59public:
60 DeferGCForAWhile(Heap& heap)
61 : m_heap(heap)
62 {
63 m_heap.incrementDeferralDepth();
64 }
65
66 ~DeferGCForAWhile()
67 {
68 m_heap.decrementDeferralDepth();
69 }
70
71private:
72 Heap& m_heap;
73};
74
75class DisallowGC : public DisallowScope<DisallowGC> {
76 WTF_MAKE_NONCOPYABLE(DisallowGC);
77 WTF_FORBID_HEAP_ALLOCATION;
78 typedef DisallowScope<DisallowGC> Base;
79public:
80#ifdef NDEBUG
81
82 ALWAYS_INLINE DisallowGC(bool = false) { }
83 ALWAYS_INLINE static void initialize() { }
84
85#else // not NDEBUG
86
87 DisallowGC(bool enabled = true)
88 : Base(enabled)
89 { }
90
91 static void initialize()
92 {
93 s_scopeReentryCount.construct();
94 }
95
96private:
97 static unsigned scopeReentryCount()
98 {
99 return *s_scopeReentryCount.get();
100 }
101 static void setScopeReentryCount(unsigned value)
102 {
103 *s_scopeReentryCount.get() = value;
104 }
105
106 JS_EXPORT_PRIVATE static LazyNeverDestroyed<ThreadSpecific<unsigned, WTF::CanBeGCThread::True>> s_scopeReentryCount;
107
108#endif // NDEBUG
109
110 friend class DisallowScope<DisallowGC>;
111};
112
113} // namespace JSC
114