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JSMarkingConstraintPrivate.cpp
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89 lines (72 loc) · 3.36 KB
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/*
* Copyright (C) 2017-2022 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 "JSMarkingConstraintPrivate.h"
#include "APICast.h"
#include "JSCellInlines.h"
#include "SimpleMarkingConstraint.h"
using namespace JSC;
namespace {
Atomic<unsigned> constraintCounter;
struct Marker : JSMarker {
AbstractSlotVisitor* visitor;
};
bool isMarked(JSMarkerRef markerRef, JSObjectRef objectRef)
{
if (!objectRef)
return true; // Null is an immortal object.
return static_cast<Marker*>(markerRef)->visitor->isMarked(toJS(objectRef));
}
void mark(JSMarkerRef markerRef, JSObjectRef objectRef)
{
if (!objectRef)
return;
static_cast<Marker*>(markerRef)->visitor->appendHiddenUnbarriered(toJS(objectRef));
}
} // anonymous namespace
void JSContextGroupAddMarkingConstraint(JSContextGroupRef group, JSMarkingConstraint constraintCallback, void *userData)
{
VM& vm = *toJS(group);
JSLockHolder locker(vm);
unsigned constraintIndex = constraintCounter.exchangeAdd(1);
// This is a guess. The algorithm should be correct no matter what we pick. This means
// that we expect this constraint to mark things even during a stop-the-world full GC, but
// we don't expect it to be able to mark anything at the very start of a GC before anything
// else gets marked.
ConstraintVolatility volatility = ConstraintVolatility::GreyedByMarking;
auto constraint = makeUnique<SimpleMarkingConstraint>(
toCString("Amc", constraintIndex, "(", RawPointer(constraintCallback), ")"),
toCString("API Marking Constraint #", constraintIndex, " (", RawPointer(constraintCallback), ", ", RawPointer(userData), ")"),
MAKE_MARKING_CONSTRAINT_EXECUTOR_PAIR(([constraintCallback, userData] (AbstractSlotVisitor& visitor) {
Marker marker;
marker.IsMarked = isMarked;
marker.Mark = mark;
marker.visitor = &visitor;
constraintCallback(&marker, userData);
})),
volatility,
ConstraintConcurrency::Sequential);
vm.heap.addMarkingConstraint(WTF::move(constraint));
}