vasco.callgraph
Class PointsToAnalysis

java.lang.Object
  vasco.InterProceduralAnalysis<M,N,A>
      vasco.OldForwardInterProceduralAnalysis<SootMethod,Unit,PointsToGraph>
          vasco.callgraph.PointsToAnalysis

public class PointsToAnalysis
extends OldForwardInterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

An inter-procedural analysis for constructing a context-sensitive call graph on-the-fly.

This analysis uses the value-based context-sensitive inter-procedural framework and was developed as an example instantiation of the framework.

The analysis uses PointsToGraph objects as data flow values, which in turn abstracts heap locations using allocation sites.

Warning! The current implementation of this class uses the old API (see OldForwardInterProceduralAnalysis) without separate call/return flow functions. The developer is currently in the process of migrating this implementation to the new API (see ForwardInterProceduralAnalysis).

Author:

Rohan Padhye

Field Summary

Fields inherited from class vasco.OldForwardInterProceduralAnalysis

analysisStack

Fields inherited from class vasco.InterProceduralAnalysis

contexts, contextTransitions, freeResultsOnTheFly, reverse, verbose, worklist

Constructor Summary

PointsToAnalysis()
Constructs a new points-to analysis as a forward-flow inter-procedural analysis.

Method Summary

PointsToGraph	boundaryValue(SootMethod entryPoint) Returns a points-to graph with the locals of main initialised to null, except the command-line arguments which are initialised to an array of strings.
PointsToGraph	copy(PointsToGraph graph) Returns a copy of the given points-to graph.
protected PointsToGraph	flowFunction(Context<SootMethod,Unit,PointsToGraph> context, Unit unit, PointsToGraph in) Performs operations on points-to graphs depending on the statement inside a CFG node.
protected PointsToGraph	handleInvoke(Context<SootMethod,Unit,PointsToGraph> callerContext, Stmt callStmt, InvokeExpr ie, PointsToGraph in) Handles a call site by resolving the targets of the method invocation.
PointsToGraph	meet(PointsToGraph op1, PointsToGraph op2) Returns the union of two points-to graphs.
ProgramRepresentation<SootMethod,Unit>	programRepresentation() Returns a program representation on top of which the inter-procedural analysis runs.
PointsToGraph	topValue() The default data flow value (lattice top) is the empty points-to graph.

Methods inherited from class vasco.OldForwardInterProceduralAnalysis

doAnalysis, initContext, processCall

Methods inherited from class vasco.InterProceduralAnalysis

getCallers, getContext, getContexts, getContextTransitionTable, getMeetOverValidPathsSolution, getMethods, getTargets

Methods inherited from class java.lang.Object

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

Constructor Detail

PointsToAnalysis

public PointsToAnalysis()

Constructs a new points-to analysis as a forward-flow inter-procedural analysis.

Method Detail

boundaryValue

public PointsToGraph boundaryValue(SootMethod entryPoint)

Returns a points-to graph with the locals of main initialised to null, except the command-line arguments which are initialised to an array of strings.

Specified by:

boundaryValue in class InterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

Parameters:

entryPoint - an entry point specified by the program representation

Returns:

the data flow value at the boundary

See Also:

ProgramRepresentation.getEntryPoints()

copy

public PointsToGraph copy(PointsToGraph graph)

Returns a copy of the given points-to graph.

Specified by:

copy in class InterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

Parameters:

graph - the data flow value to copy

Returns:

a new data flow value which is a copy of the argument

flowFunction

protected PointsToGraph flowFunction(Context<SootMethod,Unit,PointsToGraph> context,
                                     Unit unit,
                                     PointsToGraph in)

Performs operations on points-to graphs depending on the statement inside a CFG node.

Specified by:

flowFunction in class OldForwardInterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

handleInvoke

protected PointsToGraph handleInvoke(Context<SootMethod,Unit,PointsToGraph> callerContext,
                                     Stmt callStmt,
                                     InvokeExpr ie,
                                     PointsToGraph in)

Handles a call site by resolving the targets of the method invocation. The resultant flow is the union of the exit flows of all the analysed callees. If the method returns a reference-like value, this is also taken into account.

meet

public PointsToGraph meet(PointsToGraph op1,
                          PointsToGraph op2)

Returns the union of two points-to graphs.

Specified by:

meet in class InterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

Parameters:

op1 - the first operand

op2 - the second operand

Returns:

a new data flow which is the result of the meet operation of the two operands

topValue

public PointsToGraph topValue()

The default data flow value (lattice top) is the empty points-to graph.

Specified by:

topValue in class InterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

Returns:

the default data flow value (lattice top)

programRepresentation

public ProgramRepresentation<SootMethod,Unit> programRepresentation()

Description copied from class: InterProceduralAnalysis

Returns a program representation on top of which the inter-procedural analysis runs. The program representation is used to build control flow graphs of individual procedures and resolve targets of virtual call sites.

Specified by:

programRepresentation in class InterProceduralAnalysis<SootMethod,Unit,PointsToGraph>

Returns:

The program representation underlying this analysis