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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 7  * published by the Free Software Foundation.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
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12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
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25 package jdk.incubator.code.bytecode.impl;
26 
27 import java.util.List;
28 import java.util.Map;
29 import jdk.incubator.code.Block;
30 import jdk.incubator.code.CodeContext;
31 import jdk.incubator.code.CodeTransformer;
32 import jdk.incubator.code.Op;
33 import jdk.incubator.code.TypeElement;
34 import jdk.incubator.code.Value;
35 import jdk.incubator.code.dialect.java.JavaType;
36 
37 /**
38  * The terminating conditional multi-branch operation modeling {@code tableswitch} and {@code lookupswitch} instructions.
39  * <p>
40  * This operation accepts an int operand, variable number of distinct constant labels
41  * and the same number of successors.
42  * When the operand is matching one of the labels, the relevant successor is selected.
43  * If none of the labels is matching, the default successor is selected.
44  * Default is a successor with corresponds null label value.
45  * The selected successor refers to the next block to branch to.
46  */
47 public final class ConstantLabelSwitchOp extends Op implements Op.BlockTerminating {
48 
49     final List<Integer> labels;
50     final List<Block.Reference> targets;
51 
52     public ConstantLabelSwitchOp(Value intSelector, List<Integer> labels, List<Block.Reference> targets) {
53         super(List.of(intSelector));
54         assert targets.size() == labels.size();
55         this.labels = labels;
56         this.targets = targets;
57     }
58 
59     ConstantLabelSwitchOp(ConstantLabelSwitchOp that, CodeContext cc) {
60         super(that, cc);
61         this.labels = that.labels;
62         this.targets = that.targets.stream().map(cc::getSuccessorOrCreate).toList();
63     }
64 
65     @Override
66     public ConstantLabelSwitchOp transform(CodeContext cc, CodeTransformer ot) {
67         return new ConstantLabelSwitchOp(this, cc);
68     }
69 
70     @Override
71     public TypeElement resultType() {
72         return JavaType.VOID;
73     }
74 
75     public List<Integer> labels() {
76         return labels;
77     }
78 
79     @Override
80     public List<Block.Reference> successors() {
81         return targets;
82     }
83 
84     @Override
85     public Map<String, Object> externalize() {
86         return Map.of("", labels);
87     }
88 
89 }