org.jikesrvm.compilers.opt.dfsolver
Class DF_AbstractCell

java.lang.Object
  org.jikesrvm.compilers.opt.dfsolver.DF_AbstractCell

All Implemented Interfaces:

DF_LatticeCell, GraphElement, GraphNode

Direct Known Subclasses:

DominatorCell, IndexPropagation.ArrayCell, IndexPropagation.ObjectCell

public abstract class DF_AbstractCell
extends Object
implements DF_LatticeCell

DF_LatticeCell.java Represents a single lattice cell in a dataflow system.

uses

private final HashSet<DF_Equation> uses

Set of DF_Equations which use this lattice cell.

defs

private final HashSet<DF_Equation> defs

Set of DF_Equations which define this lattice cell.

index

private int index

Field used for GraphNode interface. TODO: is this needed?

scratch

private int scratch

DF_AbstractCell

public DF_AbstractCell()

Default Constructor

DF_AbstractCell

public DF_AbstractCell(int capacity)

This constructor bounds the initial capacity to save space.

Parameters:

capacity - the initial capacity of the "uses" set

getUses

public Iterator<DF_Equation> getUses()

Returns an enumeration of the equations in which this lattice cell is used.

Specified by:

getUses in interface DF_LatticeCell

Returns:

an enumeration of the equations in which this lattice cell is used

getDefs

public Iterator<DF_Equation> getDefs()

Return an enumeration of the equations in which this lattice cell is defined.

Specified by:

getDefs in interface DF_LatticeCell

Returns:

an enumeration of the equations in which this lattice cell is defined

toString

public abstract String toString()

Return a string representation of the cell

Specified by:

toString in interface DF_LatticeCell

Overrides:

toString in class Object

Returns:

a string representation of the cell

addUse

public void addUse(DF_Equation eq)

Note that this variable appears on the RHS of an equation.

Specified by:

addUse in interface DF_LatticeCell

Parameters:

eq - the equation

addDef

public void addDef(DF_Equation eq)

Note that this variable appears on the LHS of an equation.

Specified by:

addDef in interface DF_LatticeCell

Parameters:

eq - the equation

inNodes

public GraphNodeEnumeration inNodes()

Description copied from interface: GraphNode

Get an enumeration of all the edges at which edges that point to this node are sourced.

Specified by:

inNodes in interface GraphNode

Returns:

an enumeration of all the edges at which edges that point to this node are sourced.

outNodes

public GraphNodeEnumeration outNodes()

Description copied from interface: GraphNode

Get an enumeration of all the edges to which edges sourced at this node point.

Specified by:

outNodes in interface GraphNode

Returns:

an enumeration of all the edges to which edges sourced at this node point.

setIndex

public void setIndex(int i)

Implementation of GraphNode interface.

Specified by:

setIndex in interface GraphNode

getIndex

public int getIndex()

Implementation of GraphNode interface.

Specified by:

getIndex in interface GraphNode

Returns:

the index of this node in its graph.

getScratch

public int getScratch()

Description copied from interface: GraphElement

read the scratch field of int type

Specified by:

getScratch in interface GraphElement

Returns:

the contents of the int scratch field

setScratch

public int setScratch(int o)

Description copied from interface: GraphElement

set the scratch field of int type

Specified by:

setScratch in interface GraphElement

Parameters:

o - the new contents of the int scratch field