/*
 * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package org.graalvm.compiler.hotspot.nodes;

import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;

import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.graph.Node;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.lir.VirtualStackSlot;
import org.graalvm.compiler.nodeinfo.NodeCycles;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.calc.FloatingNode;
import org.graalvm.compiler.nodes.spi.LIRLowerable;
import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
import org.graalvm.compiler.word.Word;
import org.graalvm.compiler.word.WordTypes;

import jdk.vm.ci.meta.Value;

/**
 * Node that is used to maintain a stack based counter of how many locks are currently held.
 */
@NodeInfo(cycles = NodeCycles.CYCLES_2, size = SIZE_1)
public final class MonitorCounterNode extends FloatingNode implements LIRLowerable, Node.ValueNumberable {
    public static final NodeClass<MonitorCounterNode> TYPE = NodeClass.create(MonitorCounterNode.class);

    public MonitorCounterNode(@InjectedNodeParameter WordTypes wordTypes) {
        super(TYPE, StampFactory.forKind(wordTypes.getWordKind()));
    }

    @Override
    public void generate(NodeLIRBuilderTool gen) {
        assert graph().getNodes().filter(MonitorCounterNode.class).count() == 1 : "monitor counters not canonicalized to single instance";
        VirtualStackSlot counter = gen.getLIRGeneratorTool().getResult().getFrameMapBuilder().allocateStackSlots(1);
        Value result = gen.getLIRGeneratorTool().emitAddress(counter);
        gen.setResult(this, result);
    }

    @NodeIntrinsic
    public static native Word counter();
}
