8013914: Removed explicit LineNumberNodes that were too brittle when code moves around, and also introduced unnecessary footprint. Introduced the Statement node and fixed dead code elimination issues that were discovered by the absense of labels for LineNumberNodes.
Reviewed-by: jlaskey, attila
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package jdk.nashorn.internal.ir;
import java.util.Arrays;
import java.util.List;
import jdk.nashorn.internal.codegen.Label;
import jdk.nashorn.internal.ir.annotations.Immutable;
/**
* This class represents a node from which control flow can execute
* a {@code break} statement
*/
@Immutable
public abstract class BreakableNode extends LexicalContextNode {
/** break label. */
protected final Label breakLabel;
/**
* Constructor
*
* @param lineNumber line number
* @param token token
* @param finish finish
* @param breakLabel break label
*/
protected BreakableNode(final int lineNumber, final long token, final int finish, final Label breakLabel) {
super(lineNumber, token, finish);
this.breakLabel = breakLabel;
}
/**
* Copy constructor
*
* @param breakableNode source node
*/
protected BreakableNode(final BreakableNode breakableNode) {
super(breakableNode);
this.breakLabel = new Label(breakableNode.getBreakLabel());
}
@Override
public abstract Node ensureUniqueLabels(final LexicalContext lc);
/**
* Check whether this can be broken out from without using a label,
* e.g. everything but Blocks, basically
* @return true if breakable without label
*/
protected boolean isBreakableWithoutLabel() {
return true;
}
/**
* Return the break label, i.e. the location to go to on break.
* @return the break label
*/
public Label getBreakLabel() {
return breakLabel;
}
/**
* Return the labels associated with this node. Breakable nodes that
* aren't LoopNodes only have a break label -> the location immediately
* afterwards the node in code
* @return list of labels representing locations around this node
*/
public List<Label> getLabels() {
return Arrays.asList(breakLabel);
}
}