/*

 * Copyright (c) 2011, 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.nodes.extended;

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.PrimitiveStamp;

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

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

import org.graalvm.compiler.graph.Node;

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.ReinterpretNode;

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

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.VirtualObjectNode;

import org.graalvm.word.LocationIdentity;

import jdk.vm.ci.meta.Assumptions;

import jdk.vm.ci.meta.Constant;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.JavaKind;

import jdk.vm.ci.meta.ResolvedJavaField;

import jdk.vm.ci.meta.ResolvedJavaType;

/**

 * Load of a value from a location specified as an offset relative to an object. No null check is

 * performed before the load.

 */

@NodeInfo(cycles = CYCLES_2, size = SIZE_1)

public class RawLoadNode extends UnsafeAccessNode implements Lowerable, Virtualizable, Canonicalizable {

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

    /**

     * This constructor exists for node intrinsics that need a stamp based on {@code accessKind}.

     */

    public RawLoadNode(ValueNode object, ValueNode offset, JavaKind accessKind, LocationIdentity locationIdentity) {

        this(object, offset, accessKind, locationIdentity, false);

    }

    public RawLoadNode(ValueNode object, ValueNode offset, JavaKind accessKind, LocationIdentity locationIdentity, boolean forceAnyLocation) {

        super(TYPE, StampFactory.forKind(accessKind.getStackKind()), object, offset, accessKind, locationIdentity, forceAnyLocation);

    }

    /**

     * This constructor exists for node intrinsics that need a stamp based on the return type of the

     * {@link org.graalvm.compiler.graph.Node.NodeIntrinsic} annotated method.

     */

    public RawLoadNode(@InjectedNodeParameter Stamp stamp, ValueNode object, ValueNode offset, LocationIdentity locationIdentity, JavaKind accessKind) {

        super(TYPE, stamp, object, offset, accessKind, locationIdentity, false);

    }

    protected RawLoadNode(NodeClass<? extends RawLoadNode> c, ValueNode object, ValueNode offset, JavaKind accessKind, LocationIdentity locationIdentity) {

        super(c, StampFactory.forKind(accessKind.getStackKind()), object, offset, accessKind, locationIdentity, false);

    }

    @Override

    public void lower(LoweringTool tool) {

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

    }

    @Override

    public void virtualize(VirtualizerTool tool) {

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

        if (alias instanceof VirtualObjectNode) {

            VirtualObjectNode virtual = (VirtualObjectNode) alias;

            ValueNode offsetValue = tool.getAlias(offset());

            if (offsetValue.isConstant()) {

                long off = offsetValue.asJavaConstant().asLong();

                if (entryIndex != -1) {

                    ValueNode entry = tool.getEntry(virtual, entryIndex);

                    JavaKind entryKind = virtual.entryKind(entryIndex);

                    if (entry.getStackKind() == getStackKind() || entryKind == accessKind()) {

                        if (!(entry.stamp(NodeView.DEFAULT).isCompatible(stamp(NodeView.DEFAULT)))) {

                            if (entry.stamp(NodeView.DEFAULT) instanceof PrimitiveStamp && stamp instanceof PrimitiveStamp) {

                                PrimitiveStamp p1 = (PrimitiveStamp) stamp;

                                PrimitiveStamp p2 = (PrimitiveStamp) entry.stamp(NodeView.DEFAULT);

                                int width1 = p1.getBits();

                                int width2 = p2.getBits();

                                if (width1 == width2) {

                                    Node replacement = ReinterpretNode.create(p2, entry, NodeView.DEFAULT);

                                    tool.replaceWith((ValueNode) replacement);

                                    return;

                                } else {

                                    // different bit width

                                    return;

                                }

                            } else {

                                // cannot reinterpret for arbitrary objects

                                return;

                            }

                        }

                        tool.replaceWith(entry);

                    }

                }

            }

        }

    }

    @Override

    public Node canonical(CanonicalizerTool tool) {

        if (!isAnyLocationForced() && getLocationIdentity().isAny()) {

            ValueNode targetObject = object();

            if (offset().isConstant() && targetObject.isConstant() && !targetObject.isNullConstant()) {

                ConstantNode objectConstant = (ConstantNode) targetObject;

                ResolvedJavaType type = StampTool.typeOrNull(objectConstant);

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

                    JavaConstant arrayConstant = objectConstant.asJavaConstant();

                    if (arrayConstant != null) {

                        int stableDimension = objectConstant.getStableDimension();

                        if (stableDimension > 0) {

                            NodeView view = NodeView.from(tool);

                            long constantOffset = offset().asJavaConstant().asLong();

                            Constant constant = stamp(view).readConstant(tool.getConstantReflection().getMemoryAccessProvider(), arrayConstant, constantOffset);

                            boolean isDefaultStable = objectConstant.isDefaultStable();

                            if (constant != null && (isDefaultStable || !constant.isDefaultForKind())) {

                                return ConstantNode.forConstant(stamp(view), constant, stableDimension - 1, isDefaultStable, tool.getMetaAccess());

                            }

                        }

                    }

                }

            }

        }

        return super.canonical(tool);

    }

    @Override

    protected ValueNode cloneAsFieldAccess(Assumptions assumptions, ResolvedJavaField field) {

        return LoadFieldNode.create(assumptions, object(), field);

    }

    @Override

    protected ValueNode cloneAsArrayAccess(ValueNode location, LocationIdentity identity) {

        return new RawLoadNode(object(), location, accessKind(), identity);

    }

    @NodeIntrinsic

    public static native Object load(Object object, long offset, @ConstantNodeParameter JavaKind kind, @ConstantNodeParameter LocationIdentity locationIdentity);

}