dk.brics.xact.analysis.transformations
Class ReachingDefinitionsAnalysis

java.lang.Object
  dk.brics.xact.analysis.transformations.ReachingDefinitionsAnalysis

All Implemented Interfaces:

AnalysisInterface<Map<Variable,Set<Assignment>>>

public class ReachingDefinitionsAnalysis
extends Object
implements AnalysisInterface<Map<Variable,Set<Assignment>>>

Lattice and transfer functions for reaching definitions analysis. Maps each variable to a set of all statements that may assign to that variable.

Constructor Summary

ReachingDefinitionsAnalysis()
Constructs a new analysis object.

Method Summary

boolean	merge(Map<Variable,Set<Assignment>> source, VariableFilter filter, Map<Variable,Set<Assignment>> dest) Computes the least upper bound of two lattice elements.
Map<Variable,Set<Assignment>>	newBottomElement() Constructs a new lattice bottom element.
boolean	transfer(Map<Variable,Set<Assignment>> in, Statement s, Map<Variable,Set<Assignment>> out) Computes the lattice element resulting from flowing through the given statement.

Methods inherited from class java.lang.Object

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

Constructor Detail

ReachingDefinitionsAnalysis

public ReachingDefinitionsAnalysis()

Constructs a new analysis object.

Method Detail

merge

public boolean merge(Map<Variable,Set<Assignment>> source,
                     VariableFilter filter,
                     Map<Variable,Set<Assignment>> dest)

Description copied from interface: AnalysisInterface

Computes the least upper bound of two lattice elements.

Specified by:

merge in interface AnalysisInterface<Map<Variable,Set<Assignment>>>

Parameters:

source - the first element

filter - the filter to merge through

dest - the second element and destination for the result

Returns:

true if the new value of dest is changed

newBottomElement

public Map<Variable,Set<Assignment>> newBottomElement()

Description copied from interface: AnalysisInterface

Constructs a new lattice bottom element.

Specified by:

newBottomElement in interface AnalysisInterface<Map<Variable,Set<Assignment>>>

transfer

public boolean transfer(Map<Variable,Set<Assignment>> in,
                        Statement s,
                        Map<Variable,Set<Assignment>> out)

Description copied from interface: AnalysisInterface

Computes the lattice element resulting from flowing through the given statement.

Specified by:

transfer in interface AnalysisInterface<Map<Variable,Set<Assignment>>>

Parameters:

in - the flow before the statement

out - destination for the result

Returns:

true if the new value of out is changed