edu.umd.cs.findbugs.ba

Class Dataflow<Fact,AnalysisType extends DataflowAnalysis<Fact>>

java.lang.Object

edu.umd.cs.findbugs.ba.Dataflow<Fact,AnalysisType>

Direct Known Subclasses:

AbstractDataflow, BlockTypeDataflow, CallListDataflow, ConstantDataflow, LiveLocalStoreDataflow, LockDataflow, ObligationDataflow, ReturnPathDataflow, ReturnPathTypeDataflow, TypeDataflow, TypeQualifierDataflow

public class Dataflow<Fact,AnalysisType extends DataflowAnalysis<Fact>>
extends java.lang.Object

Perform dataflow analysis on a method using a control flow graph. Both forward and backward analyses can be performed.

• The "start" point of each block is the entry (forward analyses) or the exit (backward analyses).
• The "result" point of each block is the exit (forward analyses) or the entry (backward analyses).

The analysis's transfer function is applied to transform the meet of the results of the block's logical predecessors (the block's start facts) into the block's result facts.

Author:

David Hovemeyer

See Also:

CFG, DataflowAnalysis

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	DEBUG

Constructor Summary

Constructors

Constructor and Description
Dataflow(CFG cfg, AnalysisType analysis) Constructor.

Method Summary

Modifier and Type	Method and Description
void	dumpDataflow(AnalysisType analysis)
void	execute() Run the algorithm.
AnalysisType	getAnalysis() Get the analysis object.
CFG	getCFG() Get the CFG object.
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.
int	getNumIterations() Return the number of iterations of the main execution loop.
Fact	getResultFact(BasicBlock block) Get dataflow facts for end of given block.
Fact	getStartFact(BasicBlock block) Get dataflow facts for start of given block.

Methods inherited from class java.lang.Object

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

Field Detail

DEBUG

public static boolean DEBUG

Constructor Detail

Dataflow

public Dataflow(CFG cfg,
                AnalysisType analysis)

Constructor.

Parameters:

cfg - the control flow graph

analysis - the DataflowAnalysis to be run

Method Detail

execute

public void execute()
             throws DataflowAnalysisException

Run the algorithm. Afterwards, caller can use the getStartFact() and getResultFact() methods to to get dataflow facts at start and result points of each block.

Throws:

DataflowAnalysisException

getNumIterations

public int getNumIterations()

Return the number of iterations of the main execution loop.

getStartFact

public Fact getStartFact(BasicBlock block)

Get dataflow facts for start of given block.

getResultFact

public Fact getResultFact(BasicBlock block)

Get dataflow facts for end of given 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.

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.

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.

Parameters:

edge - the edge

Returns:

the fact that is true on the edge

Throws:

DataflowAnalysisException

getAnalysis

public AnalysisType getAnalysis()

Get the analysis object.

getCFG

public CFG getCFG()

Get the CFG object.

dumpDataflow

public void dumpDataflow(AnalysisType analysis)