+ // Don't emit any special code for the cleanuppad instruction. It just marks
+ // the start of a funclet.
+ FuncInfo.MBB->setIsEHFuncletEntry();
+ FuncInfo.MBB->setIsCleanupFuncletEntry();
+}
+
+/// When an invoke or a cleanupret unwinds to the next EH pad, there are
+/// many places it could ultimately go. In the IR, we have a single unwind
+/// destination, but in the machine CFG, we enumerate all the possible blocks.
+/// This function skips over imaginary basic blocks that hold catchpad,
+/// terminatepad, or catchendpad instructions, and finds all the "real" machine
+/// basic block destinations. As those destinations may not be successors of
+/// EHPadBB, here we also calculate the edge weight to those destinations. The
+/// passed-in Weight is the edge weight to EHPadBB.
+static void findUnwindDestinations(
+ FunctionLoweringInfo &FuncInfo, const BasicBlock *EHPadBB, uint32_t Weight,
+ SmallVectorImpl<std::pair<MachineBasicBlock *, uint32_t>> &UnwindDests) {
+ EHPersonality Personality =
+ classifyEHPersonality(FuncInfo.Fn->getPersonalityFn());
+ bool IsMSVCCXX = Personality == EHPersonality::MSVC_CXX;
+ bool IsCoreCLR = Personality == EHPersonality::CoreCLR;
+
+ while (EHPadBB) {
+ const Instruction *Pad = EHPadBB->getFirstNonPHI();
+ BasicBlock *NewEHPadBB = nullptr;
+ if (isa<LandingPadInst>(Pad)) {
+ // Stop on landingpads. They are not funclets.
+ UnwindDests.emplace_back(FuncInfo.MBBMap[EHPadBB], Weight);
+ break;
+ } else if (isa<CleanupPadInst>(Pad)) {
+ // Stop on cleanup pads. Cleanups are always funclet entries for all known
+ // personalities.
+ UnwindDests.emplace_back(FuncInfo.MBBMap[EHPadBB], Weight);
+ UnwindDests.back().first->setIsEHFuncletEntry();
+ break;
+ } else if (const auto *CPI = dyn_cast<CatchPadInst>(Pad)) {
+ // Add the catchpad handler to the possible destinations.
+ UnwindDests.emplace_back(FuncInfo.MBBMap[EHPadBB], Weight);
+ // In MSVC C++, catchblocks are funclets and need prologues.
+ if (IsMSVCCXX || IsCoreCLR)
+ UnwindDests.back().first->setIsEHFuncletEntry();
+ NewEHPadBB = CPI->getUnwindDest();
+ } else if (const auto *CEPI = dyn_cast<CatchEndPadInst>(Pad))
+ NewEHPadBB = CEPI->getUnwindDest();
+ else if (const auto *CEPI = dyn_cast<CleanupEndPadInst>(Pad))
+ NewEHPadBB = CEPI->getUnwindDest();
+ else
+ continue;
+
+ BranchProbabilityInfo *BPI = FuncInfo.BPI;
+ if (BPI && NewEHPadBB) {
+ // When BPI is available, the calculated weight cannot be zero as zero
+ // will be turned to a default weight in MachineBlockFrequencyInfo.
+ Weight = std::max<uint32_t>(
+ BPI->getEdgeProbability(EHPadBB, NewEHPadBB).scale(Weight), 1);
+ }
+ EHPadBB = NewEHPadBB;
+ }