darling-JavaScriptCore/heap/DeferGC.h

109 lines
3.0 KiB
C++

/*
* Copyright (C) 2013-2020 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "DisallowScope.h"
#include "Heap.h"
#include <wtf/NeverDestroyed.h>
#include <wtf/ThreadSpecific.h>
namespace JSC {
class DeferGC {
WTF_MAKE_NONCOPYABLE(DeferGC);
WTF_FORBID_HEAP_ALLOCATION;
public:
DeferGC(Heap& heap)
: m_heap(heap)
{
m_heap.incrementDeferralDepth();
}
~DeferGC()
{
if constexpr (validateDFGDoesGC)
m_heap.verifyCanGC();
m_heap.decrementDeferralDepthAndGCIfNeeded();
}
private:
Heap& m_heap;
};
class DeferGCForAWhile {
WTF_MAKE_NONCOPYABLE(DeferGCForAWhile);
WTF_FORBID_HEAP_ALLOCATION;
public:
DeferGCForAWhile(Heap& heap)
: m_heap(heap)
{
m_heap.incrementDeferralDepth();
}
~DeferGCForAWhile()
{
m_heap.decrementDeferralDepth();
}
private:
Heap& m_heap;
};
class DisallowGC : public DisallowScope<DisallowGC> {
WTF_MAKE_NONCOPYABLE(DisallowGC);
WTF_FORBID_HEAP_ALLOCATION;
typedef DisallowScope<DisallowGC> Base;
public:
#if ASSERT_ENABLED
DisallowGC() = default;
static void initialize()
{
s_scopeReentryCount.construct();
}
private:
static unsigned scopeReentryCount()
{
return *s_scopeReentryCount.get();
}
static void setScopeReentryCount(unsigned value)
{
*s_scopeReentryCount.get() = value;
}
JS_EXPORT_PRIVATE static LazyNeverDestroyed<ThreadSpecific<unsigned, WTF::CanBeGCThread::True>> s_scopeReentryCount;
#else
ALWAYS_INLINE DisallowGC() { } // We need this to placate Clang due to unused warnings.
ALWAYS_INLINE static void initialize() { }
#endif // ASSERT_ENABLED
friend class DisallowScope<DisallowGC>;
};
} // namespace JSC