/*
 * Copyright (c) 2014, 2014, 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 com.oracle.graal.truffle.nodes.typesystem;

import com.oracle.graal.api.meta.*;
import com.oracle.graal.compiler.common.calc.*;
import com.oracle.graal.compiler.common.type.*;
import com.oracle.graal.graph.*;
import com.oracle.graal.graph.spi.*;
import com.oracle.graal.nodeinfo.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.nodes.calc.*;
import com.oracle.graal.nodes.extended.*;
import com.oracle.graal.nodes.spi.*;
import com.oracle.graal.truffle.nodes.*;

/**
 * Load of a final value from a location specified as an offset relative to an object.
 *
 * Substitution for method CompilerDirectives#unsafeGet*.
 */
@NodeInfo
public final class CustomizedUnsafeLoadFinalNode extends FixedWithNextNode implements Canonicalizable, Virtualizable, Lowerable {
    @Input ValueNode object;
    @Input ValueNode offset;
    @Input ValueNode condition;
    @Input ValueNode location;
    protected final Kind accessKind;

    public CustomizedUnsafeLoadFinalNode(ValueNode object, ValueNode offset, ValueNode condition, ValueNode location, Kind accessKind) {
        super(StampFactory.forKind(accessKind.getStackKind()));
        this.object = object;
        this.offset = offset;
        this.condition = condition;
        this.location = location;
        this.accessKind = accessKind;
    }

    @Override
    public Node canonical(CanonicalizerTool tool) {
        if (object.isConstant() && !object.isNullConstant() && offset.isConstant() && condition.isConstant() && condition.asJavaConstant().asInt() == 1) {
            JavaConstant constant = tool.getConstantReflection().getMemoryAccessProvider().readUnsafeConstant(accessKind, object.asJavaConstant(), offset.asJavaConstant().asLong());
            return ConstantNode.forConstant(constant, tool.getMetaAccess());
        }
        return this;
    }

    /**
     * @see UnsafeLoadNode#virtualize(VirtualizerTool)
     */
    @Override
    public void virtualize(VirtualizerTool tool) {
        State state = tool.getObjectState(object);
        if (state != null && state.getState() == EscapeState.Virtual) {
            ValueNode offsetValue = tool.getReplacedValue(offset);
            if (offsetValue.isConstant()) {
                long constantOffset = offsetValue.asJavaConstant().asLong();
                int entryIndex = state.getVirtualObject().entryIndexForOffset(constantOffset, accessKind);
                if (entryIndex != -1) {
                    ValueNode entry = state.getEntry(entryIndex);
                    if (entry.getKind() == getKind() || state.getVirtualObject().entryKind(entryIndex) == accessKind) {
                        tool.replaceWith(entry);
                    }
                }
            }
        }
    }

    @Override
    public void lower(LoweringTool tool) {
        CompareNode compare = CompareNode.createCompareNode(graph(), Condition.EQ, condition, ConstantNode.forBoolean(true, graph()));
        LocationIdentity locationIdentity;
        if (!location.isConstant() || location.isNullConstant()) {
            locationIdentity = LocationIdentity.ANY_LOCATION;
        } else {
            locationIdentity = ObjectLocationIdentity.create(location.asJavaConstant());
        }
        UnsafeLoadNode result = graph().add(new UnsafeLoadNode(object, offset, accessKind, locationIdentity, compare));
        graph().replaceFixedWithFixed(this, result);
        result.lower(tool);
    }

    @SuppressWarnings("unused")
    @NodeIntrinsic
    public static <T> T load(Object object, long offset, boolean condition, Object locationIdentity, @ConstantNodeParameter Kind kind) {
        return UnsafeLoadNode.load(object, offset, kind, null);
    }
}