1 /*
   2  * Copyright (c) 2012, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 package org.graalvm.compiler.nodes;
  24 
  25 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
  26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
  27 
  28 import org.graalvm.compiler.core.common.type.Stamp;
  29 import org.graalvm.compiler.core.common.type.StampFactory;
  30 import org.graalvm.compiler.graph.Node;
  31 import org.graalvm.compiler.graph.NodeClass;
  32 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
  33 import org.graalvm.compiler.nodeinfo.NodeInfo;
  34 import org.graalvm.compiler.nodes.java.ArrayLengthNode;
  35 import org.graalvm.compiler.nodes.spi.ArrayLengthProvider;
  36 import org.graalvm.compiler.nodes.util.GraphUtil;
  37 
  38 /**
  39  * A {@link PiNode} that also provides an array length in addition to a more refined stamp. A usage
  40  * that reads the array length, such as an {@link ArrayLengthNode}, can be canonicalized based on
  41  * this information.
  42  */
  43 @NodeInfo
  44 public final class PiArrayNode extends PiNode implements ArrayLengthProvider {
  45 
  46     public static final NodeClass<PiArrayNode> TYPE = NodeClass.create(PiArrayNode.class);
  47     @Input ValueNode length;
  48 
  49     @Override
  50     public ValueNode length() {
  51         return length;
  52     }
  53 
  54     public PiArrayNode(ValueNode object, ValueNode length, Stamp stamp) {
  55         super(TYPE, object, stamp, null);
  56         this.length = length;
  57     }
  58 
  59     @Override
  60     public Node canonical(CanonicalizerTool tool) {
  61         if (GraphUtil.arrayLength(object()) != length()) {
  62             return this;
  63         }
  64         return super.canonical(tool);
  65     }
  66 
  67     /**
  68      * Changes the stamp of an object inside a snippet to be the stamp of the node replaced by the
  69      * snippet.
  70      */
  71     @NodeIntrinsic(Placeholder.class)
  72     public static native Object piArrayCast(Object object, int length);
  73 
  74     /**
  75      * A placeholder node in a snippet that will be replaced with an appropriate {@link PiArrayNode}
  76      * when the snippet is instantiated. Using a placeholder means that {@link PiArrayNode} never
  77      * needs to deal with {@link StampFactory#forNodeIntrinsic()} stamps.
  78      */
  79     @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
  80     public static class Placeholder extends PiNode.Placeholder {
  81 
  82         public static final NodeClass<Placeholder> TYPE = NodeClass.create(Placeholder.class);
  83         @Input ValueNode length;
  84 
  85         protected Placeholder(ValueNode object, ValueNode length) {
  86             super(TYPE, object);
  87             this.length = length;
  88         }
  89 
  90         @Override
  91         public PiNode getReplacement(Stamp stampForPi) {
  92             return graph().addOrUnique(new PiArrayNode(object(), length, stampForPi));
  93         }
  94     }
  95 }