/**
* given a DelayabilityAnalysis and the computations of each unit, calculates the latest
* computation-point for each expression.<br>
* the <code>equivRhsMap</code> could be calculated on the fly, but it is <b>very</b> likely that
* it already exists (as similar maps are used for calculating Earliestness, Delayed,...<br>
* the shared set allows more efficient set-operations, when they the computation is merged with
* other analyses/computations.
*
* @param dg a ExceptionalUnitGraph
* @param delayed the delayability-analysis of the same graph.
* @param equivRhsMap all computations of the graph
* @param set the shared flowSet
*/
public LatestComputation(
UnitGraph unitGraph, DelayabilityAnalysis delayed, Map equivRhsMap, BoundedFlowSet set) {
unitToLatest = new HashMap<Unit, FlowSet>(unitGraph.size() + 1, 0.7f);
Iterator unitIt = unitGraph.iterator();
while (unitIt.hasNext()) {
/* create a new Earliest-list for each unit */
Unit currentUnit = (Unit) unitIt.next();
/* basically the latest-set is:
* (delayed) INTERSECT (comp UNION (UNION_successors ~Delayed)) =
* (delayed) MINUS ((INTERSECTION_successors Delayed) MINUS comp).
*/
FlowSet delaySet = (FlowSet) delayed.getFlowBefore(currentUnit);
/* Calculate (INTERSECTION_successors Delayed) */
FlowSet succCompSet = (FlowSet) set.topSet();
List succList = unitGraph.getSuccsOf(currentUnit);
Iterator succIt = succList.iterator();
while (succIt.hasNext()) {
Unit successor = (Unit) succIt.next();
succCompSet.intersection((FlowSet) delayed.getFlowBefore(successor), succCompSet);
}
/* remove the computation of this set: succCompSet is then:
* ((INTERSECTION_successors Delayed) MINUS comp) */
if (equivRhsMap.get(currentUnit) != null) succCompSet.remove(equivRhsMap.get(currentUnit));
/* make the difference: */
FlowSet latest = (FlowSet) delaySet.emptySet();
delaySet.difference(succCompSet, latest);
unitToLatest.put(currentUnit, latest);
}
}
public void calculateOutSet(Unit u, BoundedFlowSet inSet, BoundedFlowSet outSet) {
// If the def set is a subset of the in set, then out = in \ impure use, else
// out = (in union def) \ use
BoundedFlowSet defSet = defSetMap.get(u);
BoundedFlowSet inComplement = (BoundedFlowSet) inSet.clone();
inComplement.complement();
inComplement.intersection(defSet);
if (inComplement.size() == 0) {
inSet.copy(outSet);
outSet.difference(useSetMap.get(u));
} else {
inSet.union(defSet, outSet);
outSet.difference(useSetMap.get(u));
}
}
public FaintVariableAnalysis(Body body) {
Chain<Local> locals = body.getLocals();
allVariables = new CollectionFlowUniverse<Local>(locals);
universalSet = new ArrayPackedSet(allVariables);
for (Local l : locals) universalSet.add(l);
useSetMap = new HashMap<Unit, BoundedFlowSet>();
defSetMap = new HashMap<Unit, BoundedFlowSet>();
UnitGraph graph = new BriefUnitGraph(body);
for (Unit u : graph) {
BoundedFlowSet defSet = new ArrayPackedSet(allVariables);
BoundedFlowSet useSet = new ArrayPackedSet(allVariables);
for (ValueBox v : u.getDefBoxes()) {
// Only do this for locals. We're not going to even try to handle anything
// other than locals.
if (v.getValue() instanceof Local) {
defSet.add(v.getValue());
}
}
for (ValueBox v : u.getUseBoxes()) {
// Only do this for locals. We're not going to even try to handle anything
// other than locals.
if (v.getValue() instanceof Local) {
useSet.add(v.getValue());
}
}
defSetMap.put(u, defSet);
useSetMap.put(u, useSet);
}
}
public void mergeOutSets(List<BoundedFlowSet> outSets, BoundedFlowSet inSet) {
// Take the intersection of the out sets as the in set.
for (BoundedFlowSet set : outSets) inSet.intersection(set);
}
public BoundedFlowSet createOutSet(Unit u) {
// Initial value for the out set is the universal set
return (BoundedFlowSet) universalSet.clone();
}