1 /*
   2  * Copyright (c) 2011, 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.NodeClass;
  31 import org.graalvm.compiler.graph.spi.Simplifiable;
  32 import org.graalvm.compiler.graph.spi.SimplifierTool;
  33 import org.graalvm.compiler.nodeinfo.NodeInfo;
  34 
  35 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
  36 public final class BeginNode extends AbstractBeginNode implements Simplifiable {
  37 
  38     public static final NodeClass<BeginNode> TYPE = NodeClass.create(BeginNode.class);
  39 
  40     public BeginNode() {
  41         super(TYPE, StampFactory.forVoid());
  42     }
  43 
  44     public BeginNode(Stamp stamp) {
  45         super(TYPE, stamp);
  46     }
  47 
  48     public void trySimplify() {
  49         FixedNode prev = (FixedNode) this.predecessor();
  50         if (prev instanceof ControlSplitNode) {
  51             // This begin node is necessary.
  52         } else {
  53             // This begin node can be removed and all guards moved up to the preceding begin node.
  54             prepareDelete();
  55             graph().removeFixed(this);
  56         }
  57     }
  58 
  59     @Override
  60     public void simplify(SimplifierTool tool) {
  61         FixedNode prev = (FixedNode) this.predecessor();
  62         if (prev == null) {
  63             // This is the start node.
  64         } else if (prev instanceof ControlSplitNode) {
  65             // This begin node is necessary.
  66         } else {
  67             // This begin node can be removed and all guards moved up to the preceding begin node.
  68             prepareDelete();
  69             tool.addToWorkList(next());
  70             graph().removeFixed(this);
  71         }
  72     }
  73 
  74     public static AbstractBeginNode begin(FixedNode with) {
  75         if (with instanceof AbstractBeginNode) {
  76             return (AbstractBeginNode) with;
  77         }
  78         BeginNode begin = with.graph().add(new BeginNode());
  79         begin.setNext(with);
  80         return begin;
  81     }
  82 }