+static Instruction *getSuccPad(TerminatorInst *Terminator) {
+ BasicBlock *UnwindDest;
+ if (auto *II = dyn_cast<InvokeInst>(Terminator))
+ UnwindDest = II->getUnwindDest();
+ else if (auto *CSI = dyn_cast<CatchSwitchInst>(Terminator))
+ UnwindDest = CSI->getUnwindDest();
+ else
+ UnwindDest = cast<CleanupReturnInst>(Terminator)->getUnwindDest();
+ return UnwindDest->getFirstNonPHI();
+}
+
+void Verifier::verifySiblingFuncletUnwinds() {
+ SmallPtrSet<Instruction *, 8> Visited;
+ SmallPtrSet<Instruction *, 8> Active;
+ for (const auto &Pair : SiblingFuncletInfo) {
+ Instruction *PredPad = Pair.first;
+ if (Visited.count(PredPad))
+ continue;
+ Active.insert(PredPad);
+ TerminatorInst *Terminator = Pair.second;
+ do {
+ Instruction *SuccPad = getSuccPad(Terminator);
+ if (Active.count(SuccPad)) {
+ // Found a cycle; report error
+ Instruction *CyclePad = SuccPad;
+ SmallVector<Instruction *, 8> CycleNodes;
+ do {
+ CycleNodes.push_back(CyclePad);
+ TerminatorInst *CycleTerminator = SiblingFuncletInfo[CyclePad];
+ if (CycleTerminator != CyclePad)
+ CycleNodes.push_back(CycleTerminator);
+ CyclePad = getSuccPad(CycleTerminator);
+ } while (CyclePad != SuccPad);
+ Assert(false, "EH pads can't handle each other's exceptions",
+ ArrayRef<Instruction *>(CycleNodes));
+ }
+ // Don't re-walk a node we've already checked
+ if (!Visited.insert(SuccPad).second)
+ break;
+ // Walk to this successor if it has a map entry.
+ PredPad = SuccPad;
+ auto TermI = SiblingFuncletInfo.find(PredPad);
+ if (TermI == SiblingFuncletInfo.end())
+ break;
+ Terminator = TermI->second;
+ Active.insert(PredPad);
+ } while (true);
+ // Each node only has one successor, so we've walked all the active
+ // nodes' successors.
+ Active.clear();
+ }
+}
+