polyglot.visit
Class DeadCodeEliminator.DefUseFinder

java.lang.Object
  extended by polyglot.visit.NodeVisitor
      extended by polyglot.visit.HaltingVisitor
          extended by polyglot.visit.DeadCodeEliminator.DefUseFinder
All Implemented Interfaces:
java.lang.Cloneable, Copy
Enclosing class:
DeadCodeEliminator

protected static class DeadCodeEliminator.DefUseFinder
extends HaltingVisitor


Field Summary
protected  java.util.Set def
           
protected  java.util.Set use
           
 
Constructor Summary
DeadCodeEliminator.DefUseFinder(java.util.Set def, java.util.Set use)
           
 
Method Summary
 NodeVisitor enter(Node n)
          Begin normal traversal of a subtree rooted at n.
 Node leave(Node old, Node n, NodeVisitor v)
          This method is called after all of the children of n have been visited.
 
Methods inherited from class polyglot.visit.HaltingVisitor
bypass, bypass, bypassChildren, copy, override, visitChildren
 
Methods inherited from class polyglot.visit.NodeVisitor
begin, enter, finish, finish, leave, override, toString, visitEdge
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

def

protected java.util.Set def

use

protected java.util.Set use
Constructor Detail

DeadCodeEliminator.DefUseFinder

public DeadCodeEliminator.DefUseFinder(java.util.Set def,
                                       java.util.Set use)
Method Detail

enter

public NodeVisitor enter(Node n)
Description copied from class: NodeVisitor
Begin normal traversal of a subtree rooted at n. This gives the visitor the option of changing internal state or returning a new visitor which will be used to visit the children of n.

This method is typically called by the method enter(parent, n). If a subclass overrides the method enter(parent, n) then this method may not be called.

Overrides:
enter in class NodeVisitor
Parameters:
n - The root of the subtree to be traversed.
Returns:
The NodeVisitor which should be used to visit the children of n.

leave

public Node leave(Node old,
                  Node n,
                  NodeVisitor v)
Description copied from class: NodeVisitor
This method is called after all of the children of n have been visited. In this case, these children were visited by the visitor v. This is the last chance for the visitor to modify the tree rooted at n. This method will be called exactly the same number of times as entry is called. That is, for each node that is not overriden, enter and leave are each called exactly once.

Note that if old == n then the vistior should make a copy of n before modifying it. It should then return the modified copy.

This method is typically called by the method leave(parent, old, n v). If a subclass overrides the method leave(parent, old, n v) then this method may not be called.

Overrides:
leave in class NodeVisitor
Parameters:
old - The original state of root of the current subtree.
n - The current state of the root of the current subtree.
v - The NodeVisitor object used to visit the children.
Returns:
The final result of the traversal of the tree rooted at n.