Package edu.umd.cs.findbugs.ba

Class BasicAbstractDataflowAnalysis<Fact>

java.lang.Object

edu.umd.cs.findbugs.ba.BasicAbstractDataflowAnalysis<Fact>

All Implemented Interfaces:

DataflowAnalysis<Fact>

Direct Known Subclasses:

AbstractDataflowAnalysis, AbstractDominatorsAnalysis, BlockTypeAnalysis, ReturnPathTypeAnalysis

public abstract class BasicAbstractDataflowAnalysis<Fact>
extends java.lang.Object
implements DataflowAnalysis<Fact>

A useful starting point for defining a dataflow analysis. Handles access and caching of start and result facts for basic blocks.

Subclasses that model instructions within basic blocks should extend AbstractDataflowAnalysis.

Author:

David Hovemeyer

Constructor Summary

Constructors

Constructor	Description
BasicAbstractDataflowAnalysis()	Constructor.

Method Summary

Modifier and Type	Method	Description
void	edgeTransfer(Edge edge, Fact fact)	Edge transfer function.
java.lang.String	factToString(Fact fact)	Return a String representation of given Fact.
void	finishIteration()	Called after finishing an iteration of analysis.
Fact	getFactAfterLocation(Location location)	Get the dataflow fact representing the point just after given Location.
Fact	getFactAtLocation(Location location)	Get dataflow fact at (just before) given Location.
Fact	getFactOnEdge(Edge edge)	Get the fact that is true on the given control edge, after applying the edge transfer function (if any).
int	getLastUpdateTimestamp(Fact fact)
Fact	getResultFact(BasicBlock block)	Get the result fact for given basic block.
Fact	getStartFact(BasicBlock block)	Get the start fact for given basic block.
java.util.Iterator<Fact>	resultFactIterator()	Get an iterator over the result facts.
void	setLastUpdateTimestamp(Fact fact, int lastUpdateTimestamp)
void	startIteration()	Called before beginning an iteration of analysis.

Methods inherited from interface edu.umd.cs.findbugs.ba.DataflowAnalysis

copy, createFact, getBlockOrder, initEntryFact, isForwards, isTop, makeFactTop, meetInto, same, transfer

Methods inherited from class java.lang.Object

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

Constructor Detail

BasicAbstractDataflowAnalysis

public BasicAbstractDataflowAnalysis()

Constructor.

Method Detail

resultFactIterator

public java.util.Iterator<Fact> resultFactIterator()

Get an iterator over the result facts.

factToString

public java.lang.String factToString(Fact fact)

Description copied from interface: DataflowAnalysis

Return a String representation of given Fact. For debugging purposes.

Specified by:

factToString in interface DataflowAnalysis<Fact>

Parameters:

fact - a dataflow fact

Returns:

String representation of the fact

getStartFact

public Fact getStartFact(BasicBlock block)

Description copied from interface: DataflowAnalysis

Get the start fact for given basic block.

Specified by:

getStartFact in interface DataflowAnalysis<Fact>

Parameters:

block - the basic block

getResultFact

public Fact getResultFact(BasicBlock block)

Description copied from interface: DataflowAnalysis

Get the result fact for given basic block.

Specified by:

getResultFact in interface DataflowAnalysis<Fact>

Parameters:

block - the basic block

getFactAtLocation

public Fact getFactAtLocation(Location location)
                       throws DataflowAnalysisException

Get dataflow fact at (just before) given Location. Note "before" is meant in the logical sense, so for backward analyses, before means after the location in the control flow sense.

The default implementation ignores instructions within basic blocks. Subclasses that model individual instructions must override this method.

Specified by:

getFactAtLocation in interface DataflowAnalysis<Fact>

Parameters:

location - the Location

Returns:

the dataflow value at given Location

Throws:

DataflowAnalysisException

getFactAfterLocation

public Fact getFactAfterLocation(Location location)
                          throws DataflowAnalysisException

Get the dataflow fact representing the point just after given Location. Note "after" is meant in the logical sense, so for backward analyses, after means before the location in the control flow sense.

The default implementation ignores instructions within basic blocks. Subclasses that model individual instructions must override this method.

Specified by:

getFactAfterLocation in interface DataflowAnalysis<Fact>

Parameters:

location - the Location

Returns:

the dataflow value after given Location

Throws:

DataflowAnalysisException

getFactOnEdge

public Fact getFactOnEdge(Edge edge)
                   throws DataflowAnalysisException

Get the fact that is true on the given control edge, after applying the edge transfer function (if any).

Specified by:

getFactOnEdge in interface DataflowAnalysis<Fact>

Parameters:

edge - the edge

Returns:

the fact that is true after applying the edge transfer function

Throws:

DataflowAnalysisException

startIteration

public void startIteration()

Description copied from interface: DataflowAnalysis

Called before beginning an iteration of analysis. Each iteration visits every basic block in the CFG.

Specified by:

startIteration in interface DataflowAnalysis<Fact>

finishIteration

public void finishIteration()

Description copied from interface: DataflowAnalysis

Called after finishing an iteration of analysis.

Specified by:

finishIteration in interface DataflowAnalysis<Fact>

edgeTransfer

public void edgeTransfer(Edge edge,
                         Fact fact)
                  throws DataflowAnalysisException

Description copied from interface: DataflowAnalysis

Edge transfer function. Modify the given fact that is true on the (logical) edge source to modify it so that it is true at the (logical) edge target.

A do-nothing implementation is legal, and appropriate for analyses where branches are not significant.

Specified by:

edgeTransfer in interface DataflowAnalysis<Fact>

Parameters:

edge - the Edge

fact - a dataflow fact

Throws:

DataflowAnalysisException

getLastUpdateTimestamp

public int getLastUpdateTimestamp(Fact fact)

Specified by:

getLastUpdateTimestamp in interface DataflowAnalysis<Fact>

setLastUpdateTimestamp

public void setLastUpdateTimestamp(Fact fact,
                                   int lastUpdateTimestamp)

Specified by:

setLastUpdateTimestamp in interface DataflowAnalysis<Fact>