org.jikesrvm.compilers.opt.dfsolver

Class DF_Equation

java.lang.Object

org.jikesrvm.compilers.opt.dfsolver.DF_Equation

All Implemented Interfaces:

GraphNode

public class DF_Equation
extends Object
implements GraphNode

Represents a single Data Flow equation.

Field Summary

Fields

Modifier and Type	Field and Description
private int	index Field used for GraphNode interface.
protected DF_LatticeCell[]	operands The operands.
protected DF_Operator	operator The operator in the equation
(package private) int	topologicalNumber The number of this equation when the system is sorted in topological order.

Constructor Summary

Constructors

Constructor and Description
DF_Equation(DF_LatticeCell lhs, DF_Operator operator, DF_LatticeCell op1) Constructor for case of one operand on the right-hand side.
DF_Equation(DF_LatticeCell lhs, DF_Operator operator, DF_LatticeCell[] rhs) Constructor for case of more than three operands on the right-hand side.
DF_Equation(DF_LatticeCell lhs, DF_Operator operator, DF_LatticeCell op1, DF_LatticeCell op2) Constructor for case of two operands on the right-hand side.
DF_Equation(DF_LatticeCell lhs, DF_Operator operator, DF_LatticeCell op1, DF_LatticeCell op2, DF_LatticeCell op3) Constructor for case of three operands on the right-hand side.

Method Summary

Modifier and Type	Method and Description
(package private) boolean	evaluate() Evaluate this equation, setting a new value for the left-hand side.
int	getIndex() The index of this node in its graph.
(package private) DF_LatticeCell	getLHS() Return the left-hand side of this equation.
DF_LatticeCell[]	getOperands() Return the operands in this equation.
(package private) DF_Operator	getOperator() Return the operator for this equation
(package private) int	getTopologicalNumber() Get the topological number for this equation
boolean	hasCell(DF_LatticeCell cell) Does this equation contain an appearance of a given cell?
Enumeration<GraphNode>	inNodes() Return an enumeration of the equations upon whose results this equation depends.
Enumeration<GraphNode>	outNodes() Return an enumeration of the equations which use the result of this equation.
void	setIndex(int i) Implementation of GraphNode interface.
(package private) void	setTopologicalNumber(int n) Get the topological number for this equation
String	toString() Return a string representation of this object

Methods inherited from class java.lang.Object

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

Field Detail

operator

protected final DF_Operator operator

The operator in the equation

operands

protected final DF_LatticeCell[] operands

The operands. Operand[0] is the left hand side.

topologicalNumber

int topologicalNumber

The number of this equation when the system is sorted in topological order.

index

private int index

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

Constructor Detail

DF_Equation

DF_Equation(DF_LatticeCell lhs,
            DF_Operator operator,
            DF_LatticeCell op1)

Constructor for case of one operand on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

op1 - the first operand on the rhs

DF_Equation

DF_Equation(DF_LatticeCell lhs,
            DF_Operator operator,
            DF_LatticeCell op1,
            DF_LatticeCell op2)

Constructor for case of two operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

op1 - the first operand on the rhs

op2 - the second operand on the rhs

DF_Equation

DF_Equation(DF_LatticeCell lhs,
            DF_Operator operator,
            DF_LatticeCell op1,
            DF_LatticeCell op2,
            DF_LatticeCell op3)

Constructor for case of three operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

op1 - the first operand on the rhs

op2 - the second operand on the rhs

op3 - the third operand on the rhs

DF_Equation

DF_Equation(DF_LatticeCell lhs,
            DF_Operator operator,
            DF_LatticeCell[] rhs)

Constructor for case of more than three operands on the right-hand side.

Parameters:

lhs - the lattice cell set by this equation

operator - the equation operator

rhs - the operands of the right-hand side in order

Method Detail

evaluate

boolean evaluate()

Evaluate this equation, setting a new value for the left-hand side.

Returns:

true if the lhs value changed. false otherwise

getLHS

DF_LatticeCell getLHS()

Return the left-hand side of this equation.

Returns:

the lattice cell this equation computes

getOperands

public DF_LatticeCell[] getOperands()

Return the operands in this equation.

Returns:

the operands in this equation.

getOperator

DF_Operator getOperator()

Return the operator for this equation

Returns:

the operator for this equation

hasCell

public boolean hasCell(DF_LatticeCell cell)

Does this equation contain an appearance of a given cell?

Parameters:

cell - the cell in question

Returns:

true or false

toString

public String toString()

Return a string representation of this object

Overrides:

toString in class Object

Returns:

a string representation of this object

getTopologicalNumber

int getTopologicalNumber()

Get the topological number for this equation

Returns:

the topological number

setTopologicalNumber

void setTopologicalNumber(int n)

Get the topological number for this equation

Parameters:

n - the topological order

setIndex

public void setIndex(int i)

Implementation of GraphNode interface.

Specified by:

setIndex in interface GraphNode

getIndex

public int getIndex()

Description copied from interface: GraphNode

The index of this node in its graph. In general, this can e anarbitrary number, but after a call to Graph.compactNodeNumbering the nodes of a graph should be numbered 0 thru (# of nodes in graph - 1).

Specified by:

getIndex in interface GraphNode

Returns:

the index of this node in its graph.

outNodes

public Enumeration<GraphNode> outNodes()

Return an enumeration of the equations which use the result of this equation.

Specified by:

outNodes in interface GraphNode

Returns:

an enumeration of the equations which use the result of this equation.

inNodes

public Enumeration<GraphNode> inNodes()

Return an enumeration of the equations upon whose results this equation depends.

Specified by:

inNodes in interface GraphNode

Returns:

an enumeration of the equations upon whose results this equation depends