Package edu.umd.cs.findbugs.ba

Class StackDepthAnalysis

java.lang.Object

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

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

edu.umd.cs.findbugs.ba.ForwardDataflowAnalysis<StackDepth>

edu.umd.cs.findbugs.ba.StackDepthAnalysis

All Implemented Interfaces:

DataflowAnalysis<StackDepth>

public class StackDepthAnalysis
extends ForwardDataflowAnalysis<StackDepth>

A really simple forward dataflow analysis to find the depth of the Java operand stack. This is more of a proof of concept for the dataflow analysis framework than anything useful.

See Also:

• Dataflow
• DataflowAnalysis

Field Summary

Fields

Modifier and Type	Field	Description
static final int	BOTTOM
static final int	TOP

Constructor Summary

Constructors

Constructor	Description
StackDepthAnalysis(org.apache.bcel.generic.ConstantPoolGen cpg, DepthFirstSearch dfs)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	copy(StackDepth source, StackDepth dest)	Copy dataflow facts.
StackDepth	createFact()	Create empty (uninitialized) dataflow facts for one program point.
void	initEntryFact(StackDepth entryFact)	Initialize the "entry" fact for the graph.
boolean	isFactValid(StackDepth fact)	Determine whether the given fact is valid (neither top nor bottom).
boolean	isTop(StackDepth fact)	Is the given fact the top value.
void	makeFactTop(StackDepth fact)	Make given fact the top value.
void	meetInto(StackDepth fact, Edge edge, StackDepth result)	Meet a dataflow fact associated with an incoming edge into another fact.
boolean	same(StackDepth fact1, StackDepth fact2)	Are given dataflow facts the same?
void	transferInstruction(org.apache.bcel.generic.InstructionHandle handle, BasicBlock basicBlock, StackDepth fact)	Transfer function for a single instruction.

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

getBlockOrder, getDepthFirstSearch, isForwards

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

getFactAfterLocation, getFactAtLocation, transfer

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

Field Details

TOP

public static final int TOP

See Also:

• Constant Field Values

BOTTOM

public static final int BOTTOM

See Also:

• Constant Field Values

Constructor Details

StackDepthAnalysis

public StackDepthAnalysis(org.apache.bcel.generic.ConstantPoolGen cpg,
 DepthFirstSearch dfs)

Constructor.

Parameters:

cpg - the ConstantPoolGen of the method whose CFG we're performing the analysis on

dfs - DepthFirstSearch of the method's CFG

Method Details

createFact

public StackDepth createFact()

Description copied from interface: DataflowAnalysis

Create empty (uninitialized) dataflow facts for one program point. A valid value will be copied into it before it is used.

makeFactTop

public void makeFactTop(StackDepth fact)

Description copied from interface: DataflowAnalysis

Make given fact the top value.

isTop

public boolean isTop(StackDepth fact)

Description copied from interface: DataflowAnalysis

Is the given fact the top value.

isFactValid

public boolean isFactValid(StackDepth fact)

Description copied from class: AbstractDataflowAnalysis

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

Specified by:

isFactValid in class AbstractDataflowAnalysis<StackDepth>

copy

public void copy(StackDepth source,
 StackDepth dest)

Description copied from interface: DataflowAnalysis

Copy dataflow facts.

initEntryFact

public void initEntryFact(StackDepth entryFact)

Description copied from interface: DataflowAnalysis

Initialize the "entry" fact for the graph.

same

public boolean same(StackDepth fact1,
 StackDepth fact2)

Description copied from interface: DataflowAnalysis

Are given dataflow facts the same?

transferInstruction

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

Description copied from class: AbstractDataflowAnalysis

Transfer function for a single instruction.

Specified by:

transferInstruction in class AbstractDataflowAnalysis<StackDepth>

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

meetInto

public void meetInto(StackDepth fact,
 Edge edge,
 StackDepth result)

Description copied from interface: DataflowAnalysis

Meet a dataflow fact associated with an incoming edge into another fact. This is used to determine the start fact for a basic block.

Parameters:

fact - the predecessor fact (incoming edge)

edge - the edge from the predecessor

result - the result fact