soot.jimple.toolkits.scalar.pre.NotIsolatedAnalysis Maven / Gradle / Ivy
package soot.jimple.toolkits.scalar.pre;
/*-
* #%L
* Soot - a J*va Optimization Framework
* %%
* Copyright (C) 2002 Florian Loitsch
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 2.1 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.util.Map;
import soot.EquivalentValue;
import soot.Unit;
import soot.toolkits.graph.DirectedGraph;
import soot.toolkits.scalar.ArrayPackedSet;
import soot.toolkits.scalar.BackwardFlowAnalysis;
import soot.toolkits.scalar.BoundedFlowSet;
import soot.toolkits.scalar.CollectionFlowUniverse;
import soot.toolkits.scalar.FlowSet;
/**
* Performs a Not-Isolated-analysis on the given graph, which is basically the same as an Isolated-analysis (we just return
* the complement, as it's easier to calculate it). A computation is isolated, if it can only be used at the current
* computation-point. In other words: if the result of the computation will not be used later on the computation is
* isolated.
* The Latest-analysis helps us in finding isolated computations, as they show us points, where a precedent computation can't
* be used anymore. In completely other words: we search the interval "latest"-"computation". a computation in this interval
* would not be isolated.
*/
public class NotIsolatedAnalysis extends BackwardFlowAnalysis> {
private LatestComputation unitToLatest;
private Map unitToGen;
private FlowSet set;
/**
* Automatically performs the Isolation-analysis on the graph dg
using the Latest-computation
* latest
.
* the equivRhsMap
is only here to avoid doing these things again...
*
* @param dg
* a ExceptionalUnitGraph
* @param latest
* the latest-computation of the same graph.
* @param equivRhsMap
* the rhs of each unit (if assignment-stmt).
*/
public NotIsolatedAnalysis(DirectedGraph dg, LatestComputation latest, Map equivRhsMap) {
this(dg, latest, equivRhsMap,
new ArrayPackedSet(new CollectionFlowUniverse(equivRhsMap.values())));
}
/**
* Automatically performs the Isolation-analysis on the graph dg
using the Latest-computation
* latest
.
* the equivRhsMap
is only here to avoid doing these things again...
* the shared set allows more efficient set-operations, when this analysis is joined with other analyses/computations.
*
* @param dg
* a ExceptionalUnitGraph
* @param latest
* the latest-computation of the same graph.
* @param equivRhsMap
* the rhs of each unit (if assignment-stmt).
* @param set
* the shared set.
*/
public NotIsolatedAnalysis(DirectedGraph dg, LatestComputation latest, Map equivRhsMap,
BoundedFlowSet set) {
super(dg);
this.set = set;
unitToGen = equivRhsMap;
unitToLatest = latest;
doAnalysis();
}
@Override
protected FlowSet newInitialFlow() {
return set.emptySet();
}
@Override
protected FlowSet entryInitialFlow() {
return newInitialFlow();
}
@Override
protected void flowThrough(FlowSet in, Unit unit, FlowSet out) {
in.copy(out);
// Perform generation
EquivalentValue rhs = (EquivalentValue) unitToGen.get(unit);
if (rhs != null) {
out.add(rhs);
}
// perform kill
FlowSet latest = unitToLatest.getFlowBefore(unit);
out.difference(latest);
}
@Override
protected void merge(FlowSet inSet1, FlowSet inSet2, FlowSet outSet) {
inSet1.union(inSet2, outSet);
}
@Override
protected void copy(FlowSet sourceSet, FlowSet destSet) {
sourceSet.copy(destSet);
}
}