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/*
* Copyright (C) 2014-2021 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.
*/
#include "config.h"
#include "JITSafepoint.h"
#if ENABLE(JIT)
#include "JITPlan.h"
#include "JITScannable.h"
#include "JITWorklistThread.h"
#include "SlotVisitor.h"
namespace JSC {
Safepoint::Result::~Result()
{
RELEASE_ASSERT(m_wasChecked);
}
bool Safepoint::Result::didGetCancelled()
{
m_wasChecked = true;
return m_didGetCancelled;
}
Safepoint::Safepoint(JITPlan& plan, Result& result)
: m_vm(plan.vm())
, m_plan(plan)
, m_didCallBegin(false)
, m_result(result)
{
RELEASE_ASSERT(result.m_wasChecked);
result.m_wasChecked = false;
result.m_didGetCancelled = false;
}
Safepoint::~Safepoint()
{
RELEASE_ASSERT(m_didCallBegin);
if (JITWorklistThread* thread = m_plan.thread()) {
RELEASE_ASSERT(thread->m_safepoint == this);
thread->m_rightToRun.lock();
thread->m_safepoint = nullptr;
}
}
void Safepoint::add(Scannable* scannable)
{
RELEASE_ASSERT(!m_didCallBegin);
m_scannables.append(scannable);
}
void Safepoint::begin(bool keepDependenciesLive) WTF_IGNORES_THREAD_SAFETY_ANALYSIS
{
RELEASE_ASSERT(!m_didCallBegin);
m_didCallBegin = true;
m_keepDependenciesLive = keepDependenciesLive;
if (JITWorklistThread* data = m_plan.thread()) {
RELEASE_ASSERT(!data->m_safepoint);
data->m_safepoint = this;
data->m_rightToRun.unlockFairly();
}
}
template<typename Visitor>
void Safepoint::checkLivenessAndVisitChildren(Visitor& visitor)
{
RELEASE_ASSERT(m_didCallBegin);
if (m_result.m_didGetCancelled)
return; // We were cancelled during a previous GC!
if (!isKnownToBeLiveDuringGC(visitor))
return;
for (unsigned i = m_scannables.size(); i--;)
m_scannables[i]->visitChildren(visitor);
}
template void Safepoint::checkLivenessAndVisitChildren(AbstractSlotVisitor&);
template void Safepoint::checkLivenessAndVisitChildren(SlotVisitor&);
template<typename Visitor>
bool Safepoint::isKnownToBeLiveDuringGC(Visitor& visitor)
{
RELEASE_ASSERT(m_didCallBegin);
if (m_result.m_didGetCancelled)
return true; // We were cancelled during a previous GC, so let's not mess with it this time around - pretend it's live and move on.
return m_plan.isKnownToBeLiveDuringGC(visitor);
}
template bool Safepoint::isKnownToBeLiveDuringGC(AbstractSlotVisitor&);
template bool Safepoint::isKnownToBeLiveDuringGC(SlotVisitor&);
bool Safepoint::isKnownToBeLiveAfterGC()
{
RELEASE_ASSERT(m_didCallBegin);
if (m_result.m_didGetCancelled)
return true; // We were cancelled during a previous GC, so let's not mess with it this time around - pretend it's live and move on.
return m_plan.isKnownToBeLiveAfterGC();
}
void Safepoint::cancel()
{
RELEASE_ASSERT(m_didCallBegin);
RELEASE_ASSERT(!m_result.m_didGetCancelled); // We cannot get cancelled twice because subsequent GCs will think that we're alive and they will not do anything to us.
RELEASE_ASSERT(m_plan.stage() == JITPlanStage::Canceled);
m_result.m_didGetCancelled = true;
m_vm = nullptr;
}
bool Safepoint::keepDependenciesLive() const
{
return m_keepDependenciesLive;
}
VM* Safepoint::vm() const
{
return m_vm;
}
} // namespace JSC
#endif // ENABLE(JIT)
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