Package edu.umd.cs.findbugs.ba

Class AbstractDataflowAnalysis<Fact>

java.lang.Object

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

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

All Implemented Interfaces:

DataflowAnalysis<Fact>

Direct Known Subclasses:

BackwardDataflowAnalysis, CallListAnalysis, ForwardDataflowAnalysis, TypeQualifierDataflowAnalysis

public abstract class AbstractDataflowAnalysis<Fact>
extends BasicAbstractDataflowAnalysis<Fact>

Abstract base class providing functionality that will be useful for most dataflow analysis implementations that model instructions within basic blocks.

Author:

David Hovemeyer

See Also:

• Dataflow
• DataflowAnalysis

Constructor Summary

Constructors

Constructor	Description
AbstractDataflowAnalysis()

Method Summary

Modifier and Type	Method	Description
Fact	getFactAfterLocation(Location location)	Get the dataflow fact representing the point just after given Location.
Fact	getFactAtLocation(Location location)	Get the dataflow fact representing the point just before given Location.
abstract boolean	isFactValid(Fact fact)	Determine whether the given fact is valid (neither top nor bottom).
void	transfer(BasicBlock basicBlock, org.apache.bcel.generic.InstructionHandle end, Fact start, Fact result)	Transfer function for the analysis.
abstract void	transferInstruction(org.apache.bcel.generic.InstructionHandle handle, BasicBlock basicBlock, Fact fact)	Transfer function for a single instruction.

Methods inherited from class edu.umd.cs.findbugs.ba.BasicAbstractDataflowAnalysis

edgeTransfer, factToString, finishIteration, getFactOnEdge, getLastUpdateTimestamp, getResultFact, getStartFact, resultFactIterator, setLastUpdateTimestamp, startIteration

Methods inherited from class java.lang.Object

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

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

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

Constructor Details

AbstractDataflowAnalysis

public AbstractDataflowAnalysis()

Method Details

transferInstruction

public abstract void transferInstruction(org.apache.bcel.generic.InstructionHandle handle,
 BasicBlock basicBlock,
 Fact fact)
                                  throws DataflowAnalysisException

Transfer function for a single instruction.

Parameters:

handle - the instruction

basicBlock - the BasicBlock containing the instruction; needed to disambiguate instructions in inlined JSR subroutines

fact - which should be modified based on the instruction

Throws:

DataflowAnalysisException

isFactValid

@CheckReturnValue
public abstract boolean isFactValid(Fact fact)

Determine whether the given fact is valid (neither top nor bottom).

getFactAtLocation

public Fact getFactAtLocation(Location location)
                       throws DataflowAnalysisException

Get the dataflow fact representing the point 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.

Specified by:

getFactAtLocation in interface DataflowAnalysis<Fact>

Overrides:

getFactAtLocation in class BasicAbstractDataflowAnalysis<Fact>

Parameters:

location - the location

Returns:

the fact at the point just before the 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.

Specified by:

getFactAfterLocation in interface DataflowAnalysis<Fact>

Overrides:

getFactAfterLocation in class BasicAbstractDataflowAnalysis<Fact>

Parameters:

location - the location

Returns:

the fact at the point just after the location

Throws:

DataflowAnalysisException

transfer

public void transfer(BasicBlock basicBlock,
 @CheckForNull
 org.apache.bcel.generic.InstructionHandle end,
 Fact start,
 Fact result)
              throws DataflowAnalysisException

Description copied from interface: DataflowAnalysis

Transfer function for the analysis. Taking dataflow facts at start (which might be either the entry or exit of the block, depending on whether the analysis is forwards or backwards), modify result to be the facts at the other end of the block.

Parameters:

basicBlock - the basic block

end - if nonnull, stop before considering this instruction; otherwise, consider all of the instructions in the basic block

start - dataflow facts at beginning of block (if forward analysis) or end of block (if backwards analysis)

result - resulting dataflow facts at other end of block

Throws:

DataflowAnalysisException