1 /*
   2  * Copyright (c) 2014, 2018, 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 
  24 
  25 package org.graalvm.compiler.nodes.extended;
  26 
  27 import static org.graalvm.compiler.nodeinfo.InputType.Guard;
  28 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
  29 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
  30 
  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.graph.NodeInputList;
  35 import org.graalvm.compiler.graph.spi.Simplifiable;
  36 import org.graalvm.compiler.graph.spi.SimplifierTool;
  37 import org.graalvm.compiler.nodeinfo.NodeInfo;
  38 import org.graalvm.compiler.nodes.StructuredGraph;
  39 import org.graalvm.compiler.nodes.ValueNode;
  40 import org.graalvm.compiler.nodes.calc.FloatingNode;
  41 import org.graalvm.compiler.nodes.spi.LIRLowerable;
  42 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
  43 import org.graalvm.compiler.nodes.util.GraphUtil;
  44 
  45 @NodeInfo(allowedUsageTypes = Guard, cycles = CYCLES_0, size = SIZE_0)
  46 public final class MultiGuardNode extends FloatingNode implements GuardingNode, LIRLowerable, Simplifiable, Node.ValueNumberable {
  47     public static final NodeClass<MultiGuardNode> TYPE = NodeClass.create(MultiGuardNode.class);
  48 
  49     @OptionalInput(Guard) NodeInputList<ValueNode> guards;
  50 
  51     public MultiGuardNode(ValueNode... guards) {
  52         super(TYPE, StampFactory.forVoid());
  53         this.guards = new NodeInputList<>(this, guards);
  54     }
  55 
  56     @Override
  57     public void generate(NodeLIRBuilderTool generator) {
  58     }
  59 
  60     @Override
  61     public void simplify(SimplifierTool tool) {
  62         if (usages().filter(node -> node instanceof ValueAnchorNode).isNotEmpty()) {
  63             /*
  64              * For ValueAnchorNode usages, we can optimize MultiGuardNodes away if they depend on
  65              * zero or one floating nodes (as opposed to fixed nodes).
  66              */
  67             Node singleFloatingGuard = null;
  68             for (ValueNode guard : guards) {
  69                 if (GraphUtil.isFloatingNode(guard)) {
  70                     if (singleFloatingGuard == null) {
  71                         singleFloatingGuard = guard;
  72                     } else if (singleFloatingGuard != guard) {
  73                         return;
  74                     }
  75                 }
  76             }
  77             for (Node usage : usages().snapshot()) {
  78                 if (usage instanceof ValueAnchorNode) {
  79                     usage.replaceFirstInput(this, singleFloatingGuard);
  80                     tool.addToWorkList(usage);
  81                 }
  82             }
  83             if (usages().isEmpty()) {
  84                 GraphUtil.killWithUnusedFloatingInputs(this);
  85             }
  86         }
  87     }
  88 
  89     public void addGuard(GuardingNode g) {
  90         this.guards.add(g.asNode());
  91     }
  92 
  93     public static GuardingNode combine(GuardingNode first, GuardingNode second) {
  94         if (first == null) {
  95             return second;
  96         } else if (second == null) {
  97             return first;
  98         } else {
  99             StructuredGraph graph = first.asNode().graph();
 100             return graph.unique(new MultiGuardNode(first.asNode(), second.asNode()));
 101         }
 102     }
 103 
 104     public static GuardingNode addGuard(GuardingNode first, GuardingNode second) {
 105         if (first instanceof MultiGuardNode && second != null) {
 106             MultiGuardNode multi = (MultiGuardNode) first;
 107             multi.addGuard(second);
 108             return multi;
 109         } else {
 110             return combine(first, second);
 111         }
 112     }
 113 }