protected Node checkReachability(Term n) throws SemanticException {
FlowGraph g = currentFlowGraph();
if (g != null) {
Collection peers = g.peers(n);
if (peers != null && !peers.isEmpty()) {
boolean isInitializer = (n instanceof Initializer);
for (Iterator iter = peers.iterator(); iter.hasNext(); ) {
FlowGraph.Peer p = (FlowGraph.Peer) iter.next();
// the peer is reachable if at least one of its out items
// is reachable. This would cover all cases, except that some
// peers may have no successors (e.g. peers that throw an
// an exception that is not caught by the method). So we need
// to also check the inItem.
if (p.inItem() != null) {
DataFlowItem dfi = (DataFlowItem) p.inItem();
// there will only be one peer for an initializer,
// as it cannot occur in a finally block.
if (isInitializer && !dfi.normalReachable) {
throw new SemanticException(
"Initializers must be able to complete normally.", n.position());
}
if (dfi.reachable) {
return n.reachable(true);
}
}
if (p.outItems != null) {
for (Iterator k = p.outItems.values().iterator(); k.hasNext(); ) {
DataFlowItem item = (DataFlowItem) k.next();
if (item != null && item.reachable) {
// n is reachable.
return n.reachable(true);
}
}
}
}
// if we fall through to here, then no peer for n was reachable.
n = n.reachable(false);
// Compound statements are allowed to be unreachable
// (e.g., "{ // return; }" or "while (true) S"). If a compound
// statement is truly unreachable, one of its sub-statements will
// be also and we will report an error there.
if ((n instanceof Block && ((Block) n).statements().isEmpty())
|| (n instanceof Stmt && !(n instanceof CompoundStmt))) {
throw new SemanticException("Unreachable statement.", n.position());
}
}
}
return n;
}
protected Node checkReachability(Term n) {
FlowGraph g = currentFlowGraph();
if (g != null) {
Collection<FlowGraph.Peer> peers = g.peers(n, Term.EXIT);
if (peers != null && !peers.isEmpty()) {
boolean isInitializer = (n instanceof Initializer);
for (FlowGraph.Peer p : peers) {
// the peer is reachable if at least one of its out items
// is reachable. This would cover all cases, except that some
// peers may have no successors (e.g. peers that throw an
// an exception that is not caught by the method). So we need
// to also check the inItem.
if (p.inItem() != null) {
DataFlowItem dfi = (DataFlowItem) p.inItem();
// there will only be one peer for an initializer,
// as it cannot occur in a finally block.
if (isInitializer && !dfi.normalReachable) {
reportError(new Errors.InitializersMustCompleteNormally(n.position()));
}
if (dfi.reachable) {
return n.reachable(true);
}
}
if (p.outItems != null) {
for (Item v : p.outItems.values()) {
DataFlowItem item = (DataFlowItem) v;
if (item != null && item.reachable) {
// n is reachable.
return n.reachable(true);
}
}
}
}
// if we fall through to here, then no peer for n was reachable.
n = n.reachable(false);
}
}
return n;
}