private static SDGNode findExitNode(SDGNode node, CFG cfg) {
SDGNode entry = cfg.getEntry(node);
LinkedList<SDGNode> wl = new LinkedList<SDGNode>();
Set<SDGNode> visited = new HashSet<SDGNode>();
wl.add(entry);
while (!wl.isEmpty()) {
SDGNode n = wl.poll();
visited.add(n);
if (n.getKind() == SDGNode.Kind.EXIT) {
return n;
} else {
for (SDGEdge e : cfg.outgoingEdgesOf(n)) {
if (!visited.contains(e.getTarget()) && e.getKind() == SDGEdge.Kind.CONTROL_FLOW) {
wl.add(e.getTarget());
}
}
}
}
throw new IllegalStateException(
"Visited the following nodes, which not include an exit node: " + visited);
}
protected SDGNode reachedNode(SDGEdge edge) {
return edge.getSource();
}
@Override
public Collection<SDGNode> slice(Collection<SDGNode> criteria) {
LinkedList<SDGNode> worklist_0 = new LinkedList<SDGNode>();
LinkedList<SDGNode> worklist_1 = new LinkedList<SDGNode>();
LinkedList<SDGNode> worklist_2 = new LinkedList<SDGNode>();
HashSet<SDGNode> visited_0_1 = new HashSet<SDGNode>();
HashSet<SDGNode> visited_2 = new HashSet<SDGNode>();
worklist_0.addAll(criteria);
visited_0_1.addAll(criteria);
// System.out.println("searching for data channels");
edgeListener.init();
// die basis bildet ein iterierter zwei-phasen slice
while (!worklist_0.isEmpty()) {
// init the next iteration
visited_2.clear();
worklist_1.add(worklist_0.poll());
visited_0_1.add(worklist_1.peek());
// === phase 1 ===
// only ascend to calling procedures
while (!worklist_1.isEmpty()) {
SDGNode next = worklist_1.poll();
for (SDGEdge edge : g.incomingEdgesOf(next)) {
edgeListener.edgeEncountered(edge);
SDGNode adjacent = edge.getSource();
if (edge.getKind() == SDGEdge.Kind.INTERFERENCE
|| edge.getKind() == SDGEdge.Kind.FORK_IN
|| edge.getKind() == SDGEdge.Kind.FORK_OUT
|| edge.getKind() == SDGEdge.Kind.FORK) {
// handle thread edges - concurrency edges have to be
// traversed in the next iteration
// TODO: what about join edges? Why are thread numbers
// not taken into account?
// I suspect that this is not critical for correctness
// but rather for precision...
if (visited_0_1.add(adjacent)) {
worklist_0.add(adjacent);
}
} else if (edge.getKind() == SDGEdge.Kind.PARAMETER_OUT) {
// descend into called procedure in phase two!
if (visited_2.add(adjacent)) {
worklist_2.add(adjacent);
}
} else if (edge.getKind().isSDGEdge()) { // note that return
// edges are no
// sdg edges!
// intra-procedural or ascending edge
if (visited_0_1.add(adjacent)) {
worklist_1.add(adjacent);
}
}
}
}
// === phase 2 ===
// visit all procedures called underway
while (!worklist_2.isEmpty()) {
SDGNode next = worklist_2.poll();
for (SDGEdge edge : g.incomingEdgesOf(next)) {
edgeListener.edgeEncountered(edge);
SDGNode adjacent = edge.getSource();
if (edge.getKind() == SDGEdge.Kind.INTERFERENCE) {
// handle interference edges: create new elements for
// worklist_0
if (visited_0_1.add(adjacent)) {
worklist_0.add(adjacent);
}
} else if (edge.getKind().isSDGEdge()
&& edge.getKind() != SDGEdge.Kind.CALL
&& edge.getKind() != SDGEdge.Kind.PARAMETER_IN
&& edge.getKind() != SDGEdge.Kind.FORK
&& edge.getKind() != SDGEdge.Kind.FORK_IN) {
// intra-procedural or param-out edge
if (visited_2.add(adjacent)) {
worklist_2.add(adjacent);
}
}
}
}
}
return visited_0_1;
}
private static Set<SDGNode> filterStatic(final SDG sdg, final Set<SDGNode> nodes) {
final Set<SDGNode> filtered = new HashSet<SDGNode>();
for (SDGNode n : nodes) {
if (n.getBytecodeIndex() == BytecodeLocation.ROOT_PARAMETER) {
filtered.add(n);
}
}
LinkedList<SDGNode> work = new LinkedList<SDGNode>();
work.addAll(filtered);
while (!work.isEmpty()) {
final SDGNode n = work.removeFirst();
for (SDGEdge edge : sdg.getOutgoingEdgesOfKind(n, SDGEdge.Kind.PARAMETER_STRUCTURE)) {
final SDGNode tgt = edge.getTarget();
if (!filtered.contains(tgt)) {
filtered.add(tgt);
work.add(tgt);
}
}
}
return filtered;
}