1 /*
   2  * Copyright (c) 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.InputType.Association;
  26 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
  27 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
  28 
  29 import org.graalvm.compiler.core.common.type.Stamp;
  30 import org.graalvm.compiler.graph.IterableNodeType;
  31 import org.graalvm.compiler.graph.Node.ValueNumberable;
  32 import org.graalvm.compiler.graph.NodeClass;
  33 import org.graalvm.compiler.nodeinfo.NodeInfo;
  34 import org.graalvm.compiler.nodes.calc.FloatingNode;
  35 import org.graalvm.compiler.nodes.extended.GuardingNode;
  36 
  37 /**
  38  * A proxy is inserted at loop exits for any value that is created inside the loop (i.e. was not
  39  * live on entry to the loop) and is (potentially) used after the loop.
  40  */
  41 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
  42 public abstract class ProxyNode extends FloatingNode implements IterableNodeType, ValueNumberable {
  43 
  44     public static final NodeClass<ProxyNode> TYPE = NodeClass.create(ProxyNode.class);
  45     @Input(Association) LoopExitNode loopExit;
  46 
  47     protected ProxyNode(NodeClass<? extends ProxyNode> c, Stamp stamp, LoopExitNode proxyPoint) {
  48         super(c, stamp);
  49         assert proxyPoint != null;
  50         this.loopExit = proxyPoint;
  51     }
  52 
  53     public abstract ValueNode value();
  54 
  55     public LoopExitNode proxyPoint() {
  56         return loopExit;
  57     }
  58 
  59     @Override
  60     public boolean verify() {
  61         assert !(value() instanceof ProxyNode) || ((ProxyNode) value()).loopExit != loopExit;
  62         return super.verify();
  63     }
  64 
  65     public static ValueProxyNode forValue(ValueNode value, LoopExitNode exit, StructuredGraph graph) {
  66         return graph.unique(new ValueProxyNode(value, exit));
  67     }
  68 
  69     public static GuardProxyNode forGuard(GuardingNode value, LoopExitNode exit, StructuredGraph graph) {
  70         return graph.unique(new GuardProxyNode(value, exit));
  71     }
  72 }