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 * Copyright (c) 2014, 2015, 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.hotspot.nodes.type;

import java.util.Objects;

import org.graalvm.compiler.core.common.CompressEncoding;

import org.graalvm.compiler.core.common.LIRKind;

import org.graalvm.compiler.core.common.spi.LIRKindTool;

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

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

import jdk.vm.ci.hotspot.HotSpotCompressedNullConstant;

import jdk.vm.ci.hotspot.HotSpotMemoryAccessProvider;

import jdk.vm.ci.hotspot.HotSpotMetaspaceConstant;

import jdk.vm.ci.meta.Constant;

import jdk.vm.ci.meta.JavaConstant;

import jdk.vm.ci.meta.MemoryAccessProvider;

import jdk.vm.ci.meta.MetaAccessProvider;

public final class KlassPointerStamp extends MetaspacePointerStamp {

    private static final KlassPointerStamp KLASS = new KlassPointerStamp(false, false);

    private static final KlassPointerStamp KLASS_NON_NULL = new KlassPointerStamp(true, false);

    private static final KlassPointerStamp KLASS_ALWAYS_NULL = new KlassPointerStamp(false, true);

    private final CompressEncoding encoding;

    public static KlassPointerStamp klass() {

        return KLASS;

    }

    public static KlassPointerStamp klassNonNull() {

        return KLASS_NON_NULL;

    }

    public static KlassPointerStamp klassAlwaysNull() {

        return KLASS_ALWAYS_NULL;

    }

    private KlassPointerStamp(boolean nonNull, boolean alwaysNull) {

        this(nonNull, alwaysNull, null);

    }

    private KlassPointerStamp(boolean nonNull, boolean alwaysNull, CompressEncoding encoding) {

        super(nonNull, alwaysNull);

        this.encoding = encoding;

    }

    @Override

    protected AbstractPointerStamp copyWith(boolean newNonNull, boolean newAlwaysNull) {

        return new KlassPointerStamp(newNonNull, newAlwaysNull, encoding);

    }

    @Override

    public boolean isCompatible(Stamp otherStamp) {

        if (this == otherStamp) {

            return true;

        }

        if (otherStamp instanceof KlassPointerStamp) {

            KlassPointerStamp other = (KlassPointerStamp) otherStamp;

            return Objects.equals(this.encoding, other.encoding);

        }

        return false;

    }

    @Override

    public boolean isCompatible(Constant constant) {

        if (constant instanceof HotSpotMetaspaceConstant) {

            return ((HotSpotMetaspaceConstant) constant).asResolvedJavaType() != null;

        } else {

            return super.isCompatible(constant);

        }

    }

    @Override

    public Stamp constant(Constant c, MetaAccessProvider meta) {

        if (isCompressed()) {

            if (HotSpotCompressedNullConstant.COMPRESSED_NULL.equals(c)) {

                return new KlassPointerStamp(false, true, encoding);

            }

        } else {

            if (JavaConstant.NULL_POINTER.equals(c)) {

                return KLASS_ALWAYS_NULL;

            }

        }

        assert c instanceof HotSpotMetaspaceConstant;

        assert ((HotSpotMetaspaceConstant) c).isCompressed() == isCompressed();

        if (nonNull()) {

            return this;

        }

        if (isCompressed()) {

            return new KlassPointerStamp(true, false, encoding);

        } else {

            return KLASS_NON_NULL;

        }

    }

    @Override

    public Constant asConstant() {

        if (alwaysNull() && isCompressed()) {

            return HotSpotCompressedNullConstant.COMPRESSED_NULL;

        } else {

            return super.asConstant();

        }

    }

    @Override

    public LIRKind getLIRKind(LIRKindTool tool) {

        if (isCompressed()) {

        } else {

            return super.getLIRKind(tool);

        }

    }

    public boolean isCompressed() {

        return encoding != null;

    }

    public CompressEncoding getEncoding() {

        return encoding;

    }

    public KlassPointerStamp compressed(CompressEncoding newEncoding) {

        assert !isCompressed();

        return new KlassPointerStamp(nonNull(), alwaysNull(), newEncoding);

    }

    public KlassPointerStamp uncompressed() {

        assert isCompressed();

        return new KlassPointerStamp(nonNull(), alwaysNull());

    }

    @Override

    public Constant readConstant(MemoryAccessProvider provider, Constant base, long displacement) {

        HotSpotMemoryAccessProvider hsProvider = (HotSpotMemoryAccessProvider) provider;

        if (isCompressed()) {

            return hsProvider.readNarrowKlassPointerConstant(base, displacement);

        } else {

            return hsProvider.readKlassPointerConstant(base, displacement);

        }

    }

    @Override

    public int hashCode() {

        final int prime = 31;

        int result = super.hashCode();

        result = prime * result + ((encoding == null) ? 0 : encoding.hashCode());

        return result;

    }

    @Override

    public boolean equals(Object obj) {

        if (this == obj) {

            return true;

        }

        if (!super.equals(obj)) {

            return false;

        }

        if (!(obj instanceof KlassPointerStamp)) {

            return false;

        }

        KlassPointerStamp other = (KlassPointerStamp) obj;

        return Objects.equals(this.encoding, other.encoding);

    }

    @Override

    public String toString() {

        StringBuilder ret = new StringBuilder("Klass*");

        appendString(ret);

        if (isCompressed()) {

            ret.append("(compressed ").append(encoding).append(")");

        }

        return ret.toString();

    }

}