org.jikesrvm.compilers.opt.ssa

Class GVCongruenceClass

java.lang.Object

org.jikesrvm.compilers.opt.ssa.GVCongruenceClass

All Implemented Interfaces:

Iterable<ValueGraphVertex>

final class GVCongruenceClass
extends Object
implements Iterable<ValueGraphVertex>

This class represents a congruence class for global value numbering.

Field Summary

Fields

Modifier and Type	Field and Description
private Object	label A label representing a property of this congruence class.
private int	nParameter How many vertices in this congruence class represent parameters?
private ValueGraphVertex	representativeV A representative of the congruence class - saves having to find one
private int	valueNumber A value number representing this congruence class.
private HashSet<ValueGraphVertex>	vertices The set of vertices in this congruence class

Constructor Summary

Constructors

Constructor and Description
GVCongruenceClass(int valueNumber, Object label) Create a congruence class with a given representative value number and label.

Method Summary

Modifier and Type	Method and Description
void	addVertex(ValueGraphVertex v) Add a vertex to this congruence class.
boolean	containsParameter() Do any of the vertices in this set represent a parameter?
Object	getLabel()
ValueGraphVertex	getRepresentative() Return a representative vertex for this congruence class.
int	getValueNumber()
Iterator<ValueGraphVertex>	iterator() Return an iterator over the vertices in this congruence class
void	removeVertex(ValueGraphVertex v) Remove a vertex from this congruence class.
int	size() Return the number of vertices in this class

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Field Detail

label

private final Object label

A label representing a property of this congruence class.

valueNumber

private final int valueNumber

A value number representing this congruence class.

nParameter

private int nParameter

How many vertices in this congruence class represent parameters?

vertices

private final HashSet<ValueGraphVertex> vertices

The set of vertices in this congruence class

representativeV

private ValueGraphVertex representativeV

A representative of the congruence class - saves having to find one

Constructor Detail

GVCongruenceClass

GVCongruenceClass(int valueNumber,
                  Object label)

Create a congruence class with a given representative value number and label.

Parameters:

valueNumber - the value number of the class

label - the label of the class

Method Detail

getLabel

public Object getLabel()

getValueNumber

public int getValueNumber()

containsParameter

public boolean containsParameter()

Do any of the vertices in this set represent a parameter?

TODO: for efficiency, keep this information incrementally

Returns:

true or false

addVertex

public void addVertex(ValueGraphVertex v)

Add a vertex to this congruence class.

Parameters:

v - the vertex to add

removeVertex

public void removeVertex(ValueGraphVertex v)

Remove a vertex from this congruence class.

Parameters:

v - the vertex to remove

getRepresentative

public ValueGraphVertex getRepresentative()

Return a representative vertex for this congruence class.

Returns:

a representative vertex for this congruence class.

iterator

public Iterator<ValueGraphVertex> iterator()

Return an iterator over the vertices in this congruence class

Specified by:

iterator in interface Iterable<ValueGraphVertex>

Returns:

an iterator over the vertices in this congruence class

size

public int size()

Return the number of vertices in this class

Returns:

the number of vertices in this class