/*
 * Copyright (c) 2009, 2011, 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.nodes.extended;

import com.oracle.graal.api.meta.*;
import com.oracle.graal.graph.*;
import com.oracle.graal.graph.spi.*;
import com.oracle.graal.nodes.*;
import com.oracle.graal.nodes.spi.*;
import com.oracle.graal.nodes.type.*;

/**
 * The {@code UnsafeCastNode} produces the same value as its input, but with a different type. It
 * allows unsafe casts "sideways" in the type hierarchy. It does not allow to "drop" type
 * information, i.e., an unsafe cast is removed if the input object has a more precise or equal type
 * than the type this nodes casts to.
 */
public class UnsafeCastNode extends FloatingGuardedNode implements LIRLowerable, Virtualizable, GuardingNode, IterableNodeType, Canonicalizable, ValueProxy {

    @Input private ValueNode object;

    public UnsafeCastNode(ValueNode object, Stamp stamp) {
        super(stamp);
        this.object = object;
    }

    public UnsafeCastNode(ValueNode object, Stamp stamp, ValueNode anchor) {
        super(stamp, (GuardingNode) anchor);
        this.object = object;
    }

    public UnsafeCastNode(ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
        this(object, toType.getKind() == Kind.Object ? StampFactory.object(toType, exactType, nonNull || ObjectStamp.isObjectNonNull(object.stamp())) : StampFactory.forKind(toType.getKind()));
    }

    @Override
    public ValueNode getOriginalNode() {
        return object;
    }

    @Override
    public Node canonical(CanonicalizerTool tool) {
        assert getKind() == Kind.Object && object.getKind() == Kind.Object;

        ObjectStamp my = (ObjectStamp) stamp();
        ObjectStamp other = (ObjectStamp) object.stamp();

        if (my.type() == null || other.type() == null) {
            return this;
        }
        if (my.isExactType() && !other.isExactType()) {
            return this;
        }
        if (my.nonNull() && !other.nonNull()) {
            return this;
        }
        if (!my.type().isAssignableFrom(other.type())) {
            return this;
        }
        /*
         * The unsafe cast does not add any new type information, so it can be removed. Note that
         * this means that the unsafe cast cannot be used to "drop" type information (in which case
         * it must not be canonicalized in any case).
         */
        return object;
    }

    @Override
    public void virtualize(VirtualizerTool tool) {
        State state = tool.getObjectState(object);
        if (state != null && state.getState() == EscapeState.Virtual && ObjectStamp.typeOrNull(this) != null && ObjectStamp.typeOrNull(this).isAssignableFrom(state.getVirtualObject().type())) {
            tool.replaceWithVirtual(state.getVirtualObject());
        }
    }

    @Override
    public void generate(NodeLIRBuilderTool generator) {
        assert getKind() == Kind.Object && object.getKind() == Kind.Object;
        /*
         * The LIR only cares about the kind of an operand, not the actual type of an object. So we
         * do not have to introduce a new operand.
         */
        generator.setResult(this, generator.operand(object));
    }
}

@@ -2537,88 +2537,73 @@
 lic 
-Node canonical(CanonicalizerTool tool) %7B%0A        assert getKind() == Kind.
+boolean inferStamp() %7B%0A        if (stamp() instanceof 
 Object
+Stamp
  && 
@@ -2613,111 +2613,111 @@
 ect.
-getKind() == Kind.Object;%0A%0A        ObjectStamp my = (ObjectStamp) stamp();%0A        O
+stamp() instanceof ObjectStamp) %7B%0A            return updateStamp(((ObjectStamp) o
 bject
-S
+.s
 tamp
- other = 
+()).castTo(
 (Obj
@@ -2730,33 +2730,27 @@
 mp) 
-object.
 stamp()
+))
 ;%0A
-%0A
         
 if (
@@ -2749,56 +2749,9 @@
     
-if (my.type() == null %7C%7C other.type() == null) %7B
+%7D
 %0A   
@@ -2759,259 +2759,246 @@
     
-    
 return 
-this;%0A        %7D%0A        if (my.isExactType() && !other.isExactType()) %7B%0A  
+updateStamp(object.stamp().join(stamp()));%0A
     
+%7D%0A%0A
     
-  return this;%0A        %7D%0A        if (my.nonNull() && !other.nonNull()) %7B%0A            return this;%0A        %7D%0A        if (!my.type().isAssignableFrom(other.type
+@Override%0A    public Node canonical(CanonicalizerTool tool) %7B%0A        assert getKind() == Kind.Object && object.getKind() == Kind.Object;%0A        if (stamp().equals(object.stamp
 ()))
@@ -3019,20 +3019,22 @@
  return 
-this
+object
 ;%0A      
@@ -3040,306 +3040,50 @@
    %7D
-%0A        /*%0A         * The unsafe cast does not add any new type information, so it can be removed. Note that%0A         * this means that the unsafe cast cannot be used to %22drop%22 type information (in which case%0A         * it must not be canonicalized in any case).%0A         */%0A        return object;
+ else %7B%0A            return this;%0A        %7D
 %0A   

enable inference of more precise stamp