1 /* 2 * Copyright (c) 2012, 2020, 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; 26 27 import static org.graalvm.compiler.nodeinfo.InputType.Association; 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.graph.IterableNodeType; 32 import org.graalvm.compiler.graph.Node; 33 import org.graalvm.compiler.graph.NodeClass; 34 import org.graalvm.compiler.graph.iterators.NodeIterable; 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.FrameStateVerificationFeature; 39 import org.graalvm.compiler.nodes.util.GraphUtil; 40 41 @NodeInfo(allowedUsageTypes = {Association}, cycles = CYCLES_0, size = SIZE_0) 42 public final class LoopExitNode extends BeginStateSplitNode implements IterableNodeType, Simplifiable { 43 44 public static final NodeClass<LoopExitNode> TYPE = NodeClass.create(LoopExitNode.class); 45 46 /* 47 * The declared type of the field cannot be LoopBeginNode, because loop explosion during partial 48 * evaluation can temporarily assign a non-loop begin. This node will then be deleted shortly 49 * after - but we still must not have type system violations for that short amount of time. 50 */ 51 @Input(Association) AbstractBeginNode loopBegin; 52 LoopExitNode(LoopBeginNode loop)53 public LoopExitNode(LoopBeginNode loop) { 54 super(TYPE); 55 assert loop != null; 56 loopBegin = loop; 57 } 58 loopBegin()59 public LoopBeginNode loopBegin() { 60 return (LoopBeginNode) loopBegin; 61 } 62 63 @Override anchored()64 public NodeIterable<Node> anchored() { 65 return super.anchored().filter(n -> { 66 if (n instanceof ProxyNode) { 67 ProxyNode proxyNode = (ProxyNode) n; 68 return proxyNode.proxyPoint() != this; 69 } 70 return true; 71 }); 72 } 73 74 @Override 75 public void prepareDelete(FixedNode evacuateFrom) { 76 removeProxies(); 77 super.prepareDelete(evacuateFrom); 78 } 79 80 public void removeProxies() { 81 if (this.hasUsages()) { 82 outer: while (true) { 83 for (ProxyNode vpn : proxies().snapshot()) { 84 ValueNode value = vpn.value(); 85 vpn.replaceAtUsagesAndDelete(value); 86 if (value == this) { 87 // Guard proxy could have this input as value. 88 continue outer; 89 } 90 } 91 break; 92 } 93 } 94 } 95 96 @SuppressWarnings({"unchecked", "rawtypes"}) 97 public NodeIterable<ProxyNode> proxies() { 98 return (NodeIterable) usages().filter(n -> { 99 if (n instanceof ProxyNode) { 100 ProxyNode proxyNode = (ProxyNode) n; 101 return proxyNode.proxyPoint() == this; 102 } 103 return false; 104 }); 105 } 106 107 public void removeExit() { 108 this.removeProxies(); 109 FrameState loopStateAfter = this.stateAfter(); 110 graph().replaceFixedWithFixed(this, graph().add(new BeginNode())); 111 if (loopStateAfter != null) { 112 GraphUtil.tryKillUnused(loopStateAfter); 113 } 114 } 115 116 @Override 117 public void simplify(SimplifierTool tool) { 118 Node prev = this.predecessor(); 119 while (tool.allUsagesAvailable() && prev instanceof BeginNode && prev.hasNoUsages()) { 120 AbstractBeginNode begin = (AbstractBeginNode) prev; 121 this.setNodeSourcePosition(begin.getNodeSourcePosition()); 122 prev = prev.predecessor(); 123 graph().removeFixed(begin); 124 } 125 } 126 127 @Override 128 public boolean verify() { 129 /* 130 * State verification for loop exits is special in that loop exits with exception handling 131 * BCIs must not survive until code generation, thus they are cleared shortly before frame 132 * state assignment, thus we only verify them until their removal 133 */ 134 assert !this.graph().getFrameStateVerification().implies(FrameStateVerificationFeature.LOOP_EXITS) || this.stateAfter != null : "Loop exit must have a state until FSA " + this; 135 return super.verify(); 136 } 137 } 138