std::vector<unsigned> MinVisitNumStack;
// A single "visit" within the non-recursive DFS traversal.
- void DFSVisitOne(NodeType* N) {
+ void DFSVisitOne(NodeType *N) {
++visitNum; // Global counter for the visit order
nodeVisitNumbers[N] = visitNum;
SCCNodeStack.push_back(N);
MinVisitNumStack.push_back(visitNum);
VisitStack.push_back(std::make_pair(N, GT::child_begin(N)));
- //errs() << "TarjanSCC: Node " << N <<
+ //dbgs() << "TarjanSCC: Node " << N <<
// " : visitNum = " << visitNum << "\n";
}
// TOS has at least one more child so continue DFS
NodeType *childN = *VisitStack.back().second++;
if (!nodeVisitNumbers.count(childN)) {
- // this node has never been seen
+ // this node has never been seen.
DFSVisitOne(childN);
- } else {
- unsigned childNum = nodeVisitNumbers[childN];
- if (MinVisitNumStack.back() > childNum)
- MinVisitNumStack.back() = childNum;
+ continue;
}
+
+ unsigned childNum = nodeVisitNumbers[childN];
+ if (MinVisitNumStack.back() > childNum)
+ MinVisitNumStack.back() = childNum;
}
}
while (!VisitStack.empty()) {
DFSVisitChildren();
assert(VisitStack.back().second ==GT::child_end(VisitStack.back().first));
- NodeType* visitingN = VisitStack.back().first;
+ NodeType *visitingN = VisitStack.back().first;
unsigned minVisitNum = MinVisitNumStack.back();
VisitStack.pop_back();
MinVisitNumStack.pop_back();
if (!MinVisitNumStack.empty() && MinVisitNumStack.back() > minVisitNum)
MinVisitNumStack.back() = minVisitNum;
- //errs() << "TarjanSCC: Popped node " << visitingN <<
+ //dbgs() << "TarjanSCC: Popped node " << visitingN <<
// " : minVisitNum = " << minVisitNum << "; Node visit num = " <<
// nodeVisitNumbers[visitingN] << "\n";
- if (minVisitNum == nodeVisitNumbers[visitingN]) {
- // A full SCC is on the SCCNodeStack! It includes all nodes below
- // visitingN on the stack. Copy those nodes to CurrentSCC,
- // reset their minVisit values, and return (this suspends
- // the DFS traversal till the next ++).
- do {
- CurrentSCC.push_back(SCCNodeStack.back());
- SCCNodeStack.pop_back();
- nodeVisitNumbers[CurrentSCC.back()] = ~0U;
- } while (CurrentSCC.back() != visitingN);
- return;
- }
+ if (minVisitNum != nodeVisitNumbers[visitingN])
+ continue;
+
+ // A full SCC is on the SCCNodeStack! It includes all nodes below
+ // visitingN on the stack. Copy those nodes to CurrentSCC,
+ // reset their minVisit values, and return (this suspends
+ // the DFS traversal till the next ++).
+ do {
+ CurrentSCC.push_back(SCCNodeStack.back());
+ SCCNodeStack.pop_back();
+ nodeVisitNumbers[CurrentSCC.back()] = ~0U;
+ } while (CurrentSCC.back() != visitingN);
+ return;
}
}
typedef scc_iterator<GraphT, GT> _Self;
// Provide static "constructors"...
- static inline _Self begin(GraphT& G) { return _Self(GT::getEntryNode(G)); }
- static inline _Self end (GraphT& G) { return _Self(); }
+ static inline _Self begin(const GraphT &G){return _Self(GT::getEntryNode(G));}
+ static inline _Self end (const GraphT &G) { return _Self(); }
- // Direct loop termination test (I.fini() is more efficient than I == end())
- inline bool fini() const {
+ // Direct loop termination test: I.isAtEnd() is more efficient than I == end()
+ inline bool isAtEnd() const {
assert(!CurrentSCC.empty() || VisitStack.empty());
return CurrentSCC.empty();
}
return true;
return false;
}
+
+ /// ReplaceNode - This informs the scc_iterator that the specified Old node
+ /// has been deleted, and New is to be used in its place.
+ void ReplaceNode(NodeType *Old, NodeType *New) {
+ assert(nodeVisitNumbers.count(Old) && "Old not in scc_iterator?");
+ nodeVisitNumbers[New] = nodeVisitNumbers[Old];
+ nodeVisitNumbers.erase(Old);
+ }
};
// Global constructor for the SCC iterator.
template <class T>
-scc_iterator<T> scc_begin(T G) {
+scc_iterator<T> scc_begin(const T &G) {
return scc_iterator<T>::begin(G);
}
template <class T>
-scc_iterator<T> scc_end(T G) {
+scc_iterator<T> scc_end(const T &G) {
return scc_iterator<T>::end(G);
}
+template <class T>
+scc_iterator<Inverse<T> > scc_begin(const Inverse<T> &G) {
+ return scc_iterator<Inverse<T> >::begin(G);
+}
+
+template <class T>
+scc_iterator<Inverse<T> > scc_end(const Inverse<T> &G) {
+ return scc_iterator<Inverse<T> >::end(G);
+}
+
} // End llvm namespace
#endif