JoinPredecessor.java revision 953:221a84ef44c0 
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25
26package jdk.nashorn.internal.ir;
27
28/**
29 * Interface implemented by AST nodes that either can occur as predecessors of a control flow join, or contain a control
30 * flow join themselves. JoinPredecessor only provides a getter and setter for a {@link LocalVariableConversion}; the
31 * semantics of control flow for a particular node implementing the interface are shared between
32 * {@code LocalVariableTypesCalculator} that creates the conversions, and {@code CodeGenerator} that uses them.
33 */
34public interface JoinPredecessor {
35    /**
36     * Set the local variable conversions needed to unify their types at a control flow join point.
37     * @param lc the current lexical context
38     * @param conversion the conversions.
39     * @return this node or a different node representing the change.
40     */
41    public JoinPredecessor setLocalVariableConversion(LexicalContext lc, LocalVariableConversion conversion);
42
43    /**
44     * Returns the local variable conversions needed to unify their types at a control flow join point.
45     * @return the local variable conversions needed to unify their types at a control flow join point. Can be null.
46     * Can contain {@link LocalVariableConversion#isLive() dead conversions}.
47     */
48    public LocalVariableConversion getLocalVariableConversion();
49}
50