/*

 * Copyright (c) 2011, 2019, 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.

 *

 * 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.extended;

import static org.graalvm.compiler.core.common.GraalOptions.GeneratePIC;

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

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

import org.graalvm.compiler.core.common.type.AbstractPointerStamp;

import org.graalvm.compiler.core.common.type.ObjectStamp;

import org.graalvm.compiler.core.common.type.Stamp;

import org.graalvm.compiler.core.common.type.TypeReference;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.graph.spi.Canonicalizable;

import org.graalvm.compiler.graph.spi.CanonicalizerTool;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.calc.FloatingNode;

import org.graalvm.compiler.nodes.spi.Lowerable;

import org.graalvm.compiler.nodes.spi.LoweringTool;

import org.graalvm.compiler.nodes.spi.StampProvider;

import org.graalvm.compiler.nodes.spi.Virtualizable;

import org.graalvm.compiler.nodes.spi.VirtualizerTool;

import org.graalvm.compiler.nodes.type.StampTool;

import jdk.vm.ci.meta.ConstantReflectionProvider;

import jdk.vm.ci.meta.MetaAccessProvider;

/**

 * Loads an object's hub, or null if the object is null.

 */

@NodeInfo(cycles = CYCLES_2, size = SIZE_1)

public final class LoadHubOrNullNode extends FloatingNode implements Lowerable, Canonicalizable, Virtualizable {

    public static final NodeClass<LoadHubOrNullNode> TYPE = NodeClass.create(LoadHubOrNullNode.class);

    @Input ValueNode value;

    public ValueNode getValue() {

        return value;

    }

    private static AbstractPointerStamp hubStamp(StampProvider stampProvider, ValueNode value) {

        assert value.stamp(NodeView.DEFAULT) instanceof ObjectStamp;

        return stampProvider.createHubStamp(((ObjectStamp) value.stamp(NodeView.DEFAULT))).asMaybeNull();

    }

    public static ValueNode create(ValueNode value, StampProvider stampProvider, MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection) {

        AbstractPointerStamp stamp = hubStamp(stampProvider, value);

        return create(value, stamp, metaAccess, constantReflection);

    }

    public static ValueNode create(ValueNode value, AbstractPointerStamp stamp, MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection) {

        ValueNode synonym = findSynonym(value, stamp, metaAccess, constantReflection);

        if (synonym != null) {

            return synonym;

        }

        return new LoadHubOrNullNode(stamp, value);

    }

    public LoadHubOrNullNode(@InjectedNodeParameter StampProvider stampProvider, ValueNode value) {

        this(hubStamp(stampProvider, value), value);

    }

    public LoadHubOrNullNode(Stamp stamp, ValueNode value) {

        super(TYPE, stamp);

        this.value = value;

    }

    @Override

    public void lower(LoweringTool tool) {

        tool.getLowerer().lower(this, tool);

    }

    @Override

    public ValueNode canonical(CanonicalizerTool tool) {

        if (!GeneratePIC.getValue(tool.getOptions())) {

            NodeView view = NodeView.from(tool);

            MetaAccessProvider metaAccess = tool.getMetaAccess();

            ValueNode curValue = getValue();

            ValueNode newNode = findSynonym(curValue, (AbstractPointerStamp) stamp(view), metaAccess, tool.getConstantReflection());

            if (newNode != null) {

                return newNode;

            }

        }

        return this;

    }

    public static ValueNode findSynonym(ValueNode curValue, AbstractPointerStamp stamp, MetaAccessProvider metaAccess, ConstantReflectionProvider constantReflection) {

        if (StampTool.isPointerNonNull(stamp)) {

            return LoadHubNode.create(curValue, stamp.asNonNull(), metaAccess, constantReflection);

        }

        return null;

    }

    @Override

    public void virtualize(VirtualizerTool tool) {

        if (!GeneratePIC.getValue(tool.getOptions())) {

            ValueNode alias = tool.getAlias(getValue());

            TypeReference type = StampTool.typeReferenceOrNull(alias);

            if (type != null && type.isExact()) {

                tool.replaceWithValue(ConstantNode.forConstant(stamp(NodeView.DEFAULT), tool.getConstantReflection().asObjectHub(type.getType()), tool.getMetaAccess(), graph()));

            }

        }

    }

}