/*
 * Copyright (c) 2016, 2022, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.graalvm.compiler.nodes.java;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_2;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_2;

import org.graalvm.compiler.core.common.type.StampFactory;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.FixedWithNextNode;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.extended.MembarNode;
import org.graalvm.compiler.nodes.memory.SingleMemoryKill;
import org.graalvm.compiler.nodes.spi.Lowerable;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.nodes.spi.Virtualizable;
import org.graalvm.compiler.nodes.spi.VirtualizerTool;
import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;
import org.graalvm.word.LocationIdentity;

@NodeInfo(cycles = CYCLES_2, size = SIZE_2)
public class FinalFieldBarrierNode extends FixedWithNextNode implements Virtualizable, Lowerable, SingleMemoryKill {
    public static final NodeClass<FinalFieldBarrierNode> TYPE = NodeClass.create(FinalFieldBarrierNode.class);

    @OptionalInput private ValueNode value;

    public FinalFieldBarrierNode(ValueNode value) {
        super(TYPE, StampFactory.forVoid());
        this.value = value;
    }

    public ValueNode getValue() {
        return value;
    }

    @Override
    public void virtualize(VirtualizerTool tool) {
        if (value != null && tool.getAlias(value) instanceof VirtualObjectNode) {
            tool.delete();
        }
    }

    @Override
    public LocationIdentity getKilledLocationIdentity() {
        return LocationIdentity.ANY_LOCATION;
    }

    @Override
    public void lower(LoweringTool tool) {
        /*
         * Must ensure all stores are complete before a field value can "escape" (i.e., be read) by
         * another thread.
         */
        graph().replaceFixedWithFixed(this, graph().add(new MembarNode(MembarNode.FenceKind.CONSTRUCTOR_FREEZE)));
    }
}
