soot.jimple.toolkits.scalar.pre
Class DownSafetyAnalysis

java.lang.Object
  extended by soot.toolkits.scalar.AbstractFlowAnalysis<N,A>
      extended by soot.toolkits.scalar.FlowAnalysis<N,A>
          extended by soot.toolkits.scalar.BackwardFlowAnalysis
              extended by soot.jimple.toolkits.scalar.pre.DownSafetyAnalysis

public class DownSafetyAnalysis
extends BackwardFlowAnalysis

Performs an DownSafe-analysis on the given graph. An expression is downsafe, if the computation will occur on every path from the current point down to the END.


Field Summary
 
Fields inherited from class soot.toolkits.scalar.FlowAnalysis
filterUnitToAfterFlow, unitToAfterFlow
 
Fields inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
filterUnitToBeforeFlow, graph, unitToBeforeFlow
 
Constructor Summary
DownSafetyAnalysis(DirectedGraph dg)
          this constructor should not be used, and will throw a runtime-exception!
DownSafetyAnalysis(DirectedGraph dg, Map unitToGen, SideEffectTester sideEffect)
          this constructor automaticly performs the DownSafety-analysis.
the result of the analysis is as usual in FlowBefore (getFlowBefore()) and FlowAfter (getFlowAfter()).
DownSafetyAnalysis(DirectedGraph dg, Map unitToGen, SideEffectTester sideEffect, BoundedFlowSet set)
          this constructor automaticly performs the DownSafety-analysis.
the result of the analysis is as usual in FlowBefore (getFlowBefore()) and FlowAfter (getFlowAfter()).
as sets-operations are usually more efficient, if the original set comes from the same source, this allows to share sets.
 
Method Summary
protected  void copy(Object source, Object dest)
          Creates a copy of the source flow object in dest.
protected  Object entryInitialFlow()
          Returns the initial flow value for entry/exit graph nodes.
protected  void flowThrough(Object inValue, Object unit, Object outValue)
          Given the merge of the out sets, compute the in set for s (or in to out, depending on direction).
protected  void merge(Object in1, Object in2, Object out)
          Compute the merge of the in1 and in2 sets, putting the result into out.
protected  Object newInitialFlow()
          Returns the flow object corresponding to the initial values for each graph node.
 
Methods inherited from class soot.toolkits.scalar.BackwardFlowAnalysis
constructWorklist, doAnalysis, isForward
 
Methods inherited from class soot.toolkits.scalar.FlowAnalysis
constructOrderer, getFlowAfter
 
Methods inherited from class soot.toolkits.scalar.AbstractFlowAnalysis
getFlowBefore, merge, mergeInto, treatTrapHandlersAsEntries
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DownSafetyAnalysis

public DownSafetyAnalysis(DirectedGraph dg)
this constructor should not be used, and will throw a runtime-exception!


DownSafetyAnalysis

public DownSafetyAnalysis(DirectedGraph dg,
                          Map unitToGen,
                          SideEffectTester sideEffect)
this constructor automaticly performs the DownSafety-analysis.
the result of the analysis is as usual in FlowBefore (getFlowBefore()) and FlowAfter (getFlowAfter()).

Parameters:
dg - a ExceptionalUnitGraph.
unitToGen - the equivalentValue of each unit.
sideEffect - the SideEffectTester that performs kills.

DownSafetyAnalysis

public DownSafetyAnalysis(DirectedGraph dg,
                          Map unitToGen,
                          SideEffectTester sideEffect,
                          BoundedFlowSet set)
this constructor automaticly performs the DownSafety-analysis.
the result of the analysis is as usual in FlowBefore (getFlowBefore()) and FlowAfter (getFlowAfter()).
as sets-operations are usually more efficient, if the original set comes from the same source, this allows to share sets.

Parameters:
dg - a ExceptionalUnitGraph.
unitToGen - the equivalentValue of each unit.
sideEffect - the SideEffectTester that performs kills.
BoundedFlowSet - the shared set.
Method Detail

newInitialFlow

protected Object newInitialFlow()
Description copied from class: AbstractFlowAnalysis
Returns the flow object corresponding to the initial values for each graph node.

Specified by:
newInitialFlow in class AbstractFlowAnalysis

entryInitialFlow

protected Object entryInitialFlow()
Description copied from class: AbstractFlowAnalysis
Returns the initial flow value for entry/exit graph nodes.

Specified by:
entryInitialFlow in class AbstractFlowAnalysis

flowThrough

protected void flowThrough(Object inValue,
                           Object unit,
                           Object outValue)
Description copied from class: FlowAnalysis
Given the merge of the out sets, compute the in set for s (or in to out, depending on direction). This function often causes confusion, because the same interface is used for both forward and backward flow analyses. The first parameter is always the argument to the flow function (i.e. it is the "in" set in a forward analysis and the "out" set in a backward analysis), and the third parameter is always the result of the flow function (i.e. it is the "out" set in a forward analysis and the "in" set in a backward analysis).

Specified by:
flowThrough in class FlowAnalysis

merge

protected void merge(Object in1,
                     Object in2,
                     Object out)
Description copied from class: AbstractFlowAnalysis
Compute the merge of the in1 and in2 sets, putting the result into out. The behavior of this function depends on the implementation ( it may be necessary to check whether in1 and in2 are equal or aliased ). Used by the doAnalysis method.

Specified by:
merge in class AbstractFlowAnalysis

copy

protected void copy(Object source,
                    Object dest)
Description copied from class: AbstractFlowAnalysis
Creates a copy of the source flow object in dest.

Specified by:
copy in class AbstractFlowAnalysis