soot.jimple.toolkits.pointer
Class StrongLocalMustAliasAnalysis

java.lang.Object
  soot.toolkits.scalar.AbstractFlowAnalysis<N,A>
      soot.toolkits.scalar.FlowAnalysis<N,A>
          soot.toolkits.scalar.ForwardFlowAnalysis<Unit,HashMap<Value,Object>>
              soot.jimple.toolkits.pointer.LocalMustAliasAnalysis
                  soot.jimple.toolkits.pointer.StrongLocalMustAliasAnalysis

public class StrongLocalMustAliasAnalysis
extends LocalMustAliasAnalysis

A special version of the local must-alias analysis that takes redefinitions within loops into account. For variable that is redefined in a loop, the must-alias information is invalidated and set to LocalMustAliasAnalysis.UNKNOWN. E.g. assume the following example: while(..) { c = foo(); //(1) c.doSomething(); //(2) } While it is certainly true that c at (2) must-alias c at (1) (they have the same value number), it is also true that in a second iteration, c at (2) may not alias the previous c at (2).

Author:

Eric Bodden

Field Summary

protected Set<Integer>

invalidInstanceKeys

Fields inherited from class soot.jimple.toolkits.pointer.LocalMustAliasAnalysis

container, localsAndFieldRefs, mergePointToValueToNumber, nextNumber, NOTHING, rhsToNumber, UNKNOWN, UNKNOWN_LABEL

Fields inherited from class soot.toolkits.scalar.FlowAnalysis

filterUnitToAfterFlow, unitToAfterFlow

Fields inherited from class soot.toolkits.scalar.AbstractFlowAnalysis

filterUnitToBeforeFlow, graph, unitToBeforeFlow

Constructor Summary

StrongLocalMustAliasAnalysis(UnitGraph g)

Method Summary

String	instanceKeyString(Local l, Stmt s) Returns a string (natural number) representation of the instance key associated with l at statement s or null if there is no such key associated or UNKNOWN if the value of l at s is LocalMustAliasAnalysis.UNKNOWN.
boolean	mustAlias(Local l1, Stmt s1, Local l2, Stmt s2)

Methods inherited from class soot.jimple.toolkits.pointer.LocalMustAliasAnalysis

copy, entryInitialFlow, flowThrough, hasInfoOn, merge, merge, newInitialFlow, parameterRefNumber, thisRefNumber

Methods inherited from class soot.toolkits.scalar.ForwardFlowAnalysis

constructWorklist, doAnalysis, isForward

Methods inherited from class soot.toolkits.scalar.FlowAnalysis

constructOrderer, getFlowAfter

Methods inherited from class soot.toolkits.scalar.AbstractFlowAnalysis

getFlowBefore, mergeInto, treatTrapHandlersAsEntries

Methods inherited from class java.lang.Object

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

Field Detail

invalidInstanceKeys

protected Set<Integer> invalidInstanceKeys

Constructor Detail

StrongLocalMustAliasAnalysis

public StrongLocalMustAliasAnalysis(UnitGraph g)

Method Detail

mustAlias

public boolean mustAlias(Local l1,
                         Stmt s1,
                         Local l2,
                         Stmt s2)

Overrides:

mustAlias in class LocalMustAliasAnalysis

Returns:

true if values of l1 (at s1) and l2 (at s2) have the exact same object IDs, i.e. at statement s1 the variable l1 must point to the same object as l2 at s2.

instanceKeyString

public String instanceKeyString(Local l,
                                Stmt s)

Returns a string (natural number) representation of the instance key associated with l at statement s or null if there is no such key associated or UNKNOWN if the value of l at s is LocalMustAliasAnalysis.UNKNOWN.

Overrides:

instanceKeyString in class LocalMustAliasAnalysis

Parameters:

l - any local of the associated method

s - the statement at which to check