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 * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2017, Red Hat Inc. 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

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 * 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

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package org.graalvm.compiler.core.aarch64;

import jdk.vm.ci.aarch64.AArch64Kind;

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

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

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.lir.aarch64.AArch64AddressValue;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.FrameState;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.ValueNode;

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

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

import org.graalvm.compiler.nodes.extended.GuardingNode;

import org.graalvm.compiler.nodes.memory.ReadNode;

import org.graalvm.compiler.nodes.memory.address.AddressNode;

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

import jdk.internal.vm.compiler.word.LocationIdentity;

/**

 * AArch64-specific subclass of ReadNode that knows how to merge ZeroExtend and SignExtend into the

 * read.

 */

@NodeInfo

public class AArch64ReadNode extends ReadNode {

    public static final NodeClass<AArch64ReadNode> TYPE = NodeClass.create(AArch64ReadNode.class);

    private final IntegerStamp accessStamp;

    private final boolean isSigned;

    public AArch64ReadNode(AddressNode address, LocationIdentity location, Stamp stamp, GuardingNode guard, BarrierType barrierType, boolean nullCheck,

                    FrameState stateBefore, IntegerStamp accessStamp, boolean isSigned) {

        super(TYPE, address, location, stamp, guard, barrierType, nullCheck, stateBefore);

        this.accessStamp = accessStamp;

        this.isSigned = isSigned;

    }

    @Override

    public void generate(NodeLIRBuilderTool gen) {

        AArch64LIRGenerator lirgen = (AArch64LIRGenerator) gen.getLIRGeneratorTool();

        AArch64ArithmeticLIRGenerator arithgen = (AArch64ArithmeticLIRGenerator) lirgen.getArithmetic();

        AArch64Kind readKind = (AArch64Kind) lirgen.getLIRKind(accessStamp).getPlatformKind();

        int resultBits = ((IntegerStamp) stamp(NodeView.DEFAULT)).getBits();

        gen.setResult(this, arithgen.emitExtendMemory(isSigned, readKind, resultBits, (AArch64AddressValue) gen.operand(getAddress()), gen.state(this)));

    }

    @Override

    public Stamp getAccessStamp() {

        return accessStamp;

    }

    /**

     * replace a ReadNode with an AArch64-specific variant which knows how to merge a downstream

     * zero or sign extend into the read operation.

     *

     * @param readNode

     */

    public static void replace(ReadNode readNode) {

        assert readNode.getUsageCount() == 1;

        assert readNode.usages().first() instanceof ZeroExtendNode || readNode.usages().first() instanceof SignExtendNode;

        ValueNode usage = (ValueNode) readNode.usages().first();

        boolean isSigned = usage instanceof SignExtendNode;

        IntegerStamp accessStamp = ((IntegerStamp) readNode.getAccessStamp());

        AddressNode address = readNode.getAddress();

        LocationIdentity location = readNode.getLocationIdentity();

        Stamp stamp = usage.stamp(NodeView.DEFAULT);

        GuardingNode guard = readNode.getGuard();

        BarrierType barrierType = readNode.getBarrierType();

        boolean nullCheck = readNode.getNullCheck();

        FrameState stateBefore = readNode.stateBefore();

        AArch64ReadNode clone = new AArch64ReadNode(address, location, stamp, guard, barrierType, nullCheck, stateBefore, accessStamp, isSigned);

        StructuredGraph graph = readNode.graph();

        graph.add(clone);

        // splice out the extend node

        usage.replaceAtUsagesAndDelete(readNode);

        // swap the clone for the read

        graph.replaceFixedWithFixed(readNode, clone);

    }

}