1 /*
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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
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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
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17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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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.util.GraphUtil;
39 
40 @NodeInfo(allowedUsageTypes = {Association}, cycles = CYCLES_0, size = SIZE_0)
41 public final class LoopExitNode extends BeginStateSplitNode implements IterableNodeType, Simplifiable {
42 
43     public static final NodeClass<LoopExitNode> TYPE = NodeClass.create(LoopExitNode.class);
44 
45     /*
46      * The declared type of the field cannot be LoopBeginNode, because loop explosion during partial
47      * evaluation can temporarily assign a non-loop begin. This node will then be deleted shortly
48      * after - but we still must not have type system violations for that short amount of time.
49      */
50     @Input(Association) AbstractBeginNode loopBegin;
51 
LoopExitNode(LoopBeginNode loop)52     public LoopExitNode(LoopBeginNode loop) {
53         super(TYPE);
54         assert loop != null;
55         loopBegin = loop;
56     }
57 
loopBegin()58     public LoopBeginNode loopBegin() {
59         return (LoopBeginNode) loopBegin;
60     }
61 
62     @Override
anchored()63     public NodeIterable<Node> anchored() {
64         return super.anchored().filter(n -> {
65             if (n instanceof ProxyNode) {
66                 ProxyNode proxyNode = (ProxyNode) n;
67                 return proxyNode.proxyPoint() != this;
68             }
69             return true;
70         });
71     }
72 
73     @Override
74     public void prepareDelete(FixedNode evacuateFrom) {
75         removeProxies();
76         super.prepareDelete(evacuateFrom);
77     }
78 
79     public void removeProxies() {
80         if (this.hasUsages()) {
81             outer: while (true) {
82                 for (ProxyNode vpn : proxies().snapshot()) {
83                     ValueNode value = vpn.value();
84                     vpn.replaceAtUsagesAndDelete(value);
85                     if (value == this) {
86                         // Guard proxy could have this input as value.
87                         continue outer;
88                     }
89                 }
90                 break;
91             }
92         }
93     }
94 
95     @SuppressWarnings({"unchecked", "rawtypes"})
96     public NodeIterable<ProxyNode> proxies() {
97         return (NodeIterable) usages().filter(n -> {
98             if (n instanceof ProxyNode) {
99                 ProxyNode proxyNode = (ProxyNode) n;
100                 return proxyNode.proxyPoint() == this;
101             }
102             return false;
103         });
104     }
105 
106     public void removeExit() {
107         this.removeProxies();
108         FrameState loopStateAfter = this.stateAfter();
109         graph().replaceFixedWithFixed(this, graph().add(new BeginNode()));
110         if (loopStateAfter != null) {
111             GraphUtil.tryKillUnused(loopStateAfter);
112         }
113     }
114 
115     @Override
116     public void simplify(SimplifierTool tool) {
117         Node prev = this.predecessor();
118         while (tool.allUsagesAvailable() && prev instanceof BeginNode && prev.hasNoUsages()) {
119             AbstractBeginNode begin = (AbstractBeginNode) prev;
120             this.setNodeSourcePosition(begin.getNodeSourcePosition());
121             prev = prev.predecessor();
122             graph().removeFixed(begin);
123         }
124     }
125 }
126