1 /*
   2  * Copyright (c) 2012, 2015, 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 org.graalvm.compiler.graph.Node;
  26 import org.graalvm.compiler.graph.NodeClass;
  27 import org.graalvm.compiler.nodeinfo.InputType;
  28 import org.graalvm.compiler.nodeinfo.NodeInfo;
  29 
  30 /**
  31  * Base class for nodes that contain "virtual" state, like FrameState and VirtualObjectState.
  32  * Subclasses of this class will be treated in a special way by the scheduler.
  33  */
  34 @NodeInfo(allowedUsageTypes = {InputType.State})
  35 public abstract class VirtualState extends Node {
  36 
  37     protected VirtualState(NodeClass<? extends VirtualState> c) {
  38         super(c);
  39     }
  40 
  41     public static final NodeClass<VirtualState> TYPE = NodeClass.create(VirtualState.class);
  42 
  43     public abstract static class NodeClosure<T extends Node> {
  44 
  45         public abstract void apply(Node usage, T node);
  46     }
  47 
  48     public interface VirtualClosure {
  49 
  50         void apply(VirtualState node);
  51     }
  52 
  53     public abstract VirtualState duplicateWithVirtualState();
  54 
  55     public abstract void applyToNonVirtual(NodeClosure<? super ValueNode> closure);
  56 
  57     /**
  58      * Performs a <b>pre-order</b> iteration over all elements reachable from this state that are a
  59      * subclass of {@link VirtualState}.
  60      */
  61     public abstract void applyToVirtual(VirtualClosure closure);
  62 
  63     public abstract boolean isPartOfThisState(VirtualState state);
  64 
  65     @Override
  66     public final StructuredGraph graph() {
  67         return (StructuredGraph) super.graph();
  68     }
  69 
  70 }