StrongLocalMustAliasAnalysis (Soot - a J*va Optimization Framework 4.6.0 API)

java.lang.Object
- soot.toolkits.scalar.AbstractFlowAnalysis<N,A>
- - soot.toolkits.scalar.FlowAnalysis<N,A>
  - - soot.toolkits.scalar.ForwardFlowAnalysis<Unit,HashMap<Value,Integer>>
    - - 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

Nested Class Summary
- Nested classes/interfaces inherited from class soot.toolkits.scalar.FlowAnalysis
  FlowAnalysis.Flow

Field Summary

Fields
Modifier and Type Field Description

protected Set<Integer> invalidInstanceKeys
- Fields inherited from class soot.jimple.toolkits.pointer.LocalMustAliasAnalysis
  container, localsAndFieldRefs, mergePointToValueToNumber, nextNumber, rhsToNumber
- Fields inherited from class soot.toolkits.scalar.FlowAnalysis
  filterUnitToAfterFlow, unitToAfterFlow
- Fields inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
  filterUnitToBeforeFlow, graph, unitToBeforeFlow

Constructor Summary

Constructors
Constructor Description

StrongLocalMustAliasAnalysis(UnitGraph g)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`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.
`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
doAnalysis, isForward

Methods inherited from class soot.toolkits.scalar.FlowAnalysis
copyFreshToExisting, getFlow, getFlowAfter, getFlowBefore, omissible

Methods inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
mergeInto, treatTrapHandlersAsEntries

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - invalidInstanceKeys
```
protected final 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.
    
    Overrides:
    
    instanceKeyString in class LocalMustAliasAnalysis
    
    Parameters:
    
    l - any local of the associated method
    
    s - the statement at which to check