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 * 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

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package org.graalvm.compiler.virtual.phases.ea;

import java.util.Iterator;

import java.util.List;

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

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

import org.graalvm.compiler.debug.DebugContext;

import org.graalvm.compiler.nodes.FieldLocationIdentity;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.ValueNode;

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

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

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

import org.graalvm.compiler.options.OptionValues;

import org.graalvm.word.LocationIdentity;

import jdk.vm.ci.meta.JavaKind;

public final class PEReadEliminationBlockState extends PartialEscapeBlockState<PEReadEliminationBlockState> {

    final EconomicMap<ReadCacheEntry, ValueNode> readCache;

    static final class ReadCacheEntry {

        public final LocationIdentity identity;

        public final ValueNode object;

        public final int index;

        public final JavaKind kind;

        /* This flag does not affect hashCode or equals implementations. */

        public final boolean overflowAccess;

        ReadCacheEntry(LocationIdentity identity, ValueNode object, int index, JavaKind kind, boolean overflowAccess) {

            this.identity = identity;

            this.object = object;

            this.index = index;

            this.kind = kind;

            this.overflowAccess = overflowAccess;

        }

        @Override

        public int hashCode() {

            int result = 31 + ((identity == null) ? 0 : identity.hashCode());

            result = 31 * result + ((object == null) ? 0 : System.identityHashCode(object));

            result = 31 * result + kind.ordinal();

            return result * 31 + index;

        }

        @Override

        public boolean equals(Object obj) {

            if (!(obj instanceof ReadCacheEntry)) {

                return false;

            }

            ReadCacheEntry other = (ReadCacheEntry) obj;

            return identity.equals(other.identity) && object == other.object && index == other.index && kind == other.kind;

        }

        @Override

        public String toString() {

            return index == -1 ? (object + ":" + kind + "<" + identity + ">") : (object + "[" + index + "]:" + kind + "<" + identity + ">");

        }

    }

    public PEReadEliminationBlockState(OptionValues options, DebugContext debug) {

        super(options, debug);

        readCache = EconomicMap.create(Equivalence.DEFAULT);

    }

    public PEReadEliminationBlockState(PEReadEliminationBlockState other) {

        super(other);

        readCache = EconomicMap.create(Equivalence.DEFAULT, other.readCache);

    }

    @Override

    public String toString() {

        return super.toString() + " " + readCache;

    }

    private static JavaKind stampToJavaKind(Stamp stamp) {

        if (stamp instanceof IntegerStamp) {

            switch (((IntegerStamp) stamp).getBits()) {

                case 1:

                    return JavaKind.Boolean;

                case 8:

                    return JavaKind.Byte;

                case 16:

                    return ((IntegerStamp) stamp).isPositive() ? JavaKind.Char : JavaKind.Short;

                case 32:

                    return JavaKind.Int;

                case 64:

                    return JavaKind.Long;

                default:

                    throw new IllegalArgumentException("unexpected IntegerStamp " + stamp);

            }

        } else {

            return stamp.getStackKind();

        }

    }

    @Override

    protected void objectMaterialized(VirtualObjectNode virtual, AllocatedObjectNode representation, List<ValueNode> values) {

        if (virtual instanceof VirtualInstanceNode) {

            VirtualInstanceNode instance = (VirtualInstanceNode) virtual;

            for (int i = 0; i < instance.entryCount(); i++) {

                JavaKind declaredKind = instance.field(i).getJavaKind();

                if (declaredKind == stampToJavaKind(values.get(i).stamp(NodeView.DEFAULT))) {

                    // We won't cache unaligned field writes upon instantiation unless we add

                    // support for non-array objects in PEReadEliminationClosure.processUnsafeLoad.

                    readCache.put(new ReadCacheEntry(new FieldLocationIdentity(instance.field(i)), representation, -1, declaredKind, false), values.get(i));

                }

            }

        }

    }

    @Override

    public boolean equivalentTo(PEReadEliminationBlockState other) {

        if (!isSubMapOf(readCache, other.readCache)) {

            return false;

        }

        return super.equivalentTo(other);

    }

    public void addReadCache(ValueNode object, LocationIdentity identity, int index, JavaKind kind, boolean overflowAccess, ValueNode value, PartialEscapeClosure<?> closure) {

        ValueNode cacheObject;

        ObjectState obj = closure.getObjectState(this, object);

        if (obj != null) {

            assert !obj.isVirtual();

            cacheObject = obj.getMaterializedValue();

        } else {

            cacheObject = object;

        }

        readCache.put(new ReadCacheEntry(identity, cacheObject, index, kind, overflowAccess), value);

    }

    public ValueNode getReadCache(ValueNode object, LocationIdentity identity, int index, JavaKind kind, PartialEscapeClosure<?> closure) {

        ValueNode cacheObject;

        ObjectState obj = closure.getObjectState(this, object);

        if (obj != null) {

            assert !obj.isVirtual() : object;

            cacheObject = obj.getMaterializedValue();

        } else {

            cacheObject = object;

        }

        ValueNode cacheValue = readCache.get(new ReadCacheEntry(identity, cacheObject, index, kind, false));

        obj = closure.getObjectState(this, cacheValue);

        if (obj != null) {

            assert !obj.isVirtual();

            cacheValue = obj.getMaterializedValue();

        } else {

            // assert !scalarAliases.containsKey(cacheValue);

            cacheValue = closure.getScalarAlias(cacheValue);

        }

        return cacheValue;

    }

    public void killReadCache() {

        readCache.clear();

    }

    public void killReadCache(LocationIdentity identity, int index) {

        Iterator<ReadCacheEntry> iter = readCache.getKeys().iterator();

        while (iter.hasNext()) {

            ReadCacheEntry entry = iter.next();

            if (entry.identity.equals(identity) && (index == -1 || entry.index == -1 || index == entry.index || entry.overflowAccess)) {

                iter.remove();

            }

        }

    }

    public EconomicMap<ReadCacheEntry, ValueNode> getReadCache() {

        return readCache;

    }

}