/*

 * Copyright (c) 2013, 2016, 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.replacements.nodes;

import static org.graalvm.compiler.nodeinfo.InputType.Memory;

import static org.graalvm.compiler.nodeinfo.InputType.State;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_256;

import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_64;

import static org.graalvm.word.LocationIdentity.any;

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

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.graph.NodeClass;

import org.graalvm.compiler.graph.NodeInputList;

import org.graalvm.compiler.nodeinfo.NodeInfo;

import org.graalvm.compiler.nodes.ConstantNode;

import org.graalvm.compiler.nodes.DeoptimizingNode;

import org.graalvm.compiler.nodes.FrameState;

import org.graalvm.compiler.nodes.NamedLocationIdentity;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.java.LoadIndexedNode;

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

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

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

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

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.type.StampTool;

import org.graalvm.compiler.nodes.virtual.VirtualArrayNode;

import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;

import org.graalvm.word.LocationIdentity;

import jdk.vm.ci.code.BytecodeFrame;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.ResolvedJavaType;

@NodeInfo(cycles = CYCLES_256, size = SIZE_64)

public class BasicArrayCopyNode extends AbstractMemoryCheckpoint implements Virtualizable, MemoryCheckpoint.Single, MemoryAccess, Lowerable, DeoptimizingNode.DeoptDuring {

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

    static final int SRC_ARG = 0;

    static final int SRC_POS_ARG = 1;

    static final int DEST_ARG = 2;

    static final int DEST_POS_ARG = 3;

    static final int LENGTH_ARG = 4;

    @Input NodeInputList<ValueNode> args;

    @OptionalInput(State) FrameState stateDuring;

    @OptionalInput(Memory) protected MemoryNode lastLocationAccess;

    protected JavaKind elementKind;

    protected int bci;

    public BasicArrayCopyNode(NodeClass<? extends AbstractMemoryCheckpoint> type, ValueNode src, ValueNode srcPos, ValueNode dest, ValueNode destPos, ValueNode length, JavaKind elementKind, int bci) {

        super(type, StampFactory.forKind(JavaKind.Void));

        this.bci = bci;

        args = new NodeInputList<>(this, new ValueNode[]{src, srcPos, dest, destPos, length});

        this.elementKind = elementKind != JavaKind.Illegal ? elementKind : null;

    }

    public BasicArrayCopyNode(NodeClass<? extends AbstractMemoryCheckpoint> type, ValueNode src, ValueNode srcPos, ValueNode dest, ValueNode destPos, ValueNode length, JavaKind elementKind) {

        super(type, StampFactory.forKind(JavaKind.Void));

        this.bci = BytecodeFrame.INVALID_FRAMESTATE_BCI;

        args = new NodeInputList<>(this, new ValueNode[]{src, srcPos, dest, destPos, length});

        this.elementKind = elementKind != JavaKind.Illegal ? elementKind : null;

    }

    public ValueNode getSource() {

        return args.get(SRC_ARG);

    }

    public ValueNode getSourcePosition() {

        return args.get(SRC_POS_ARG);

    }

    public ValueNode getDestination() {

        return args.get(DEST_ARG);

    }

    public ValueNode getDestinationPosition() {

        return args.get(DEST_POS_ARG);

    }

    public ValueNode getLength() {

        return args.get(LENGTH_ARG);

    }

    public int getBci() {

        return bci;

    }

    public JavaKind getElementKind() {

        return elementKind;

    }

    @Override

    public LocationIdentity getLocationIdentity() {

        if (elementKind != null) {

            return NamedLocationIdentity.getArrayLocation(elementKind);

        }

        return any();

    }

    @Override

    public MemoryNode getLastLocationAccess() {

        return lastLocationAccess;

    }

    @Override

    public void setLastLocationAccess(MemoryNode lla) {

        updateUsagesInterface(lastLocationAccess, lla);

        lastLocationAccess = lla;

    }

    @Override

    public void lower(LoweringTool tool) {

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

    }

    private static boolean checkBounds(int position, int length, VirtualObjectNode virtualObject) {

        return position >= 0 && position + length <= virtualObject.entryCount();

    }

    private static boolean checkEntryTypes(int srcPos, int length, VirtualObjectNode src, ResolvedJavaType destComponentType, VirtualizerTool tool) {

        if (destComponentType.getJavaKind() == JavaKind.Object && !destComponentType.isJavaLangObject()) {

            for (int i = 0; i < length; i++) {

                ValueNode entry = tool.getEntry(src, srcPos + i);

                ResolvedJavaType type = StampTool.typeOrNull(entry);

                if (type == null || !destComponentType.isAssignableFrom(type)) {

                    return false;

                }

            }

        }

        return true;

    }

    /*

     * Returns true if this copy doesn't require store checks. Trivially true for primitive arrays.

     */

    public boolean isExact() {

        ResolvedJavaType srcType = StampTool.typeOrNull(getSource().stamp());

        ResolvedJavaType destType = StampTool.typeOrNull(getDestination().stamp());

        if (srcType == null || !srcType.isArray() || destType == null || !destType.isArray()) {

            return false;

        }

        if ((srcType.getComponentType().getJavaKind().isPrimitive() && destType.getComponentType().equals(srcType.getComponentType())) || getSource() == getDestination()) {

            return true;

        }

        if (StampTool.isExactType(getDestination().stamp())) {

            if (destType != null && destType.isAssignableFrom(srcType)) {

                return true;

            }

        }

        return false;

    }

    @Override

    public void virtualize(VirtualizerTool tool) {

        ValueNode sourcePosition = tool.getAlias(getSourcePosition());

        ValueNode destinationPosition = tool.getAlias(getDestinationPosition());

        ValueNode replacedLength = tool.getAlias(getLength());

        if (sourcePosition.isConstant() && destinationPosition.isConstant() && replacedLength.isConstant()) {

            int srcPosInt = sourcePosition.asJavaConstant().asInt();

            int destPosInt = destinationPosition.asJavaConstant().asInt();

            int len = replacedLength.asJavaConstant().asInt();

            ValueNode destAlias = tool.getAlias(getDestination());

            if (destAlias instanceof VirtualArrayNode) {

                VirtualArrayNode destVirtual = (VirtualArrayNode) destAlias;

                if (len < 0 || !checkBounds(destPosInt, len, destVirtual)) {

                    return;

                }

                ValueNode srcAlias = tool.getAlias(getSource());

                if (srcAlias instanceof VirtualObjectNode) {

                    if (!(srcAlias instanceof VirtualArrayNode)) {

                        return;

                    }

                    VirtualArrayNode srcVirtual = (VirtualArrayNode) srcAlias;

                    if (destVirtual.componentType().getJavaKind() != srcVirtual.componentType().getJavaKind()) {

                        return;

                    }

                    if (!checkBounds(srcPosInt, len, srcVirtual)) {

                        return;

                    }

                    if (!checkEntryTypes(srcPosInt, len, srcVirtual, destVirtual.type().getComponentType(), tool)) {

                        return;

                    }

                    for (int i = 0; i < len; i++) {

                        tool.setVirtualEntry(destVirtual, destPosInt + i, tool.getEntry(srcVirtual, srcPosInt + i), false);

                    }

                    tool.delete();

                    DebugContext debug = getDebug();

                    if (debug.isLogEnabled()) {

                        debug.log("virtualized arraycopy(%s, %d, %s, %d, %d)", getSource(), srcPosInt, getDestination(), destPosInt, len);

                    }

                } else {

                    ResolvedJavaType sourceType = StampTool.typeOrNull(srcAlias);

                    if (sourceType == null || !sourceType.isArray()) {

                        return;

                    }

                    ResolvedJavaType sourceComponentType = sourceType.getComponentType();

                    ResolvedJavaType destComponentType = destVirtual.type().getComponentType();

                    if (!sourceComponentType.equals(destComponentType)) {

                        return;

                    }

                    for (int i = 0; i < len; i++) {

                        LoadIndexedNode load = new LoadIndexedNode(graph().getAssumptions(), srcAlias, ConstantNode.forInt(i + srcPosInt, graph()), destComponentType.getJavaKind());

                        tool.addNode(load);

                        tool.setVirtualEntry(destVirtual, destPosInt + i, load, false);

                    }

                    tool.delete();

                }

            }

        }

    }

    @Override

    public boolean canDeoptimize() {

        return true;

    }

    @Override

    public FrameState stateDuring() {

        return stateDuring;

    }

    @Override

    public void setStateDuring(FrameState stateDuring) {

        updateUsages(this.stateDuring, stateDuring);

        this.stateDuring = stateDuring;

    }

    @Override

    public void computeStateDuring(FrameState currentStateAfter) {

        FrameState newStateDuring = currentStateAfter.duplicateModifiedDuringCall(getBci(), asNode().getStackKind());

        setStateDuring(newStateDuring);

    }

}