public void meetInto(
UnconditionalValueDerefSet fact,
Edge edge,
UnconditionalValueDerefSet result,
boolean onlyEdge) {
if (isExceptionEdge(edge) && !onlyEdge) {
if (DEBUG) {
System.out.println("Skipping exception edge");
}
return;
}
ValueNumber knownNonnullOnBranch = null;
// Edge transfer function
if (isFactValid(fact)) {
fact = propagateDerefSetsToMergeInputValues(fact, edge);
if (invDataflow != null) {
knownNonnullOnBranch = findValueKnownNonnullOnBranch(fact, edge);
if (knownNonnullOnBranch != null) {
fact = duplicateFact(fact);
fact.clearDerefSet(knownNonnullOnBranch);
}
}
}
boolean isBackEdge = edge.isBackwardInBytecode();
Set<Integer> loopExitBranches = ClassContext.getLoopExitBranches(method, methodGen);
assert loopExitBranches != null;
boolean sourceIsTopOfLoop = edge.sourceIsTopOfLoop(loopExitBranches);
if (sourceIsTopOfLoop && edge.getType() == EdgeTypes.FALL_THROUGH_EDGE) {
isBackEdge = true;
}
/*
if (false && (edge.getType() == EdgeTypes.IFCMP_EDGE || sourceIsTopOfLoop)) {
System.out.println("Meet into " + edge);
System.out.println(" foo2: " + sourceIsTopOfLoop);
System.out.println(" getType: " + edge.getType());
System.out.println(" Backedge according to bytecode: " + isBackEdge);
System.out.println(" Fact hashCode: " + System.identityHashCode(result));
System.out.println(" Initial fact: " + result);
System.out.println(" Edge fact: " + fact);
}
*/
if (result.isTop() || fact.isBottom()) {
// Make result identical to other fact
copy(fact, result);
if (ASSUME_NONZERO_TRIP_LOOPS && isBackEdge && !fact.isTop()) {
result.resultsFromBackEdge = true;
}
} else if (ASSUME_NONZERO_TRIP_LOOPS && isBackEdge && !fact.isTop()) {
result.unionWith(fact, vnaDataflow.getAnalysis().getFactory());
result.resultsFromBackEdge = true;
if (DEBUG) {
System.out.println(
"\n Forcing union of " + System.identityHashCode(result) + " due to backedge info");
System.out.println(" result: " + result);
}
} else if (result.isBottom() || fact.isTop()) {
// No change in result fact
} else {
// Dataflow merge
// (intersection of unconditional deref values)
if (ASSUME_NONZERO_TRIP_LOOPS && result.resultsFromBackEdge) {
result.backEdgeUpdateCount++;
if (result.backEdgeUpdateCount < 10) {
if (DEBUG) {
System.out.println(
"\n Union update of " + System.identityHashCode(result) + " due to backedge info");
}
result.unionWith(fact, vnaDataflow.getAnalysis().getFactory());
return;
}
}
result.mergeWith(fact, knownNonnullOnBranch, vnaDataflow.getAnalysis().getFactory());
if (DEBUG) {
System.out.println(" updated: " + System.identityHashCode(result));
System.out.println(" result: " + result);
}
}
if (DEBUG && isBackEdge && edge.getType() == EdgeTypes.IFCMP_EDGE) {
System.out.println(" result: " + result);
}
}
