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.replacements.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 java.util.ArrayList;
  29 
  30 import org.graalvm.compiler.api.replacements.Snippet.VarargsParameter;
  31 import org.graalvm.compiler.core.common.type.StampFactory;
  32 import org.graalvm.compiler.graph.Node;
  33 import org.graalvm.compiler.graph.NodeClass;
  34 import org.graalvm.compiler.nodeinfo.NodeInfo;
  35 import org.graalvm.compiler.nodes.FixedWithNextNode;
  36 import org.graalvm.compiler.nodes.LoopBeginNode;
  37 
  38 /**
  39  * Placeholder node to denote to snippet preparation that the following loop must be completely
  40  * unrolled.
  41  *
  42  * @see VarargsParameter
  43  */
  44 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
  45 public final class ExplodeLoopNode extends FixedWithNextNode {
  46     public static final NodeClass<ExplodeLoopNode> TYPE = NodeClass.create(ExplodeLoopNode.class);
  47 
  48     public ExplodeLoopNode() {
  49         super(TYPE, StampFactory.forVoid());
  50     }
  51 
  52     public LoopBeginNode findLoopBegin() {
  53         Node currentNext = next();
  54         ArrayList<Node> succs = new ArrayList<>();
  55         while (!(currentNext instanceof LoopBeginNode)) {
  56             assert currentNext != null : "cannot find loop after " + this;
  57             for (Node n : currentNext.cfgSuccessors()) {
  58                 succs.add(n);
  59             }
  60             if (succs.size() == 1) {
  61                 currentNext = succs.get(0);
  62             } else {
  63                 return null;
  64             }
  65         }
  66         return (LoopBeginNode) currentNext;
  67     }
  68 
  69     /**
  70      * A call to this method must be placed immediately prior to the loop that is to be exploded.
  71      */
  72     @NodeIntrinsic
  73     public static native void explodeLoop();
  74 }