am 31195f0b: Merge "Update aosp/master llvm for rebase to r233350"

* commit '31195f0bdca6ee2a5e72d07edf13e1d81206d949':
  Update aosp/master llvm for rebase to r233350

1 files changed, 1244 insertions, 385 deletions

diff --git a/lib/CodeGen/WinEHPrepare.cpp b/lib/CodeGen/WinEHPrepare.cpp
index 6f712a9..ab0f96e 100644
--- a/lib/CodeGen/WinEHPrepare.cpp
+++ b/lib/CodeGen/WinEHPrepare.cpp
@@ -16,6 +16,8 @@
 
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/TinyPtrVector.h"
 #include "llvm/Analysis/LibCallSemantics.h"
 #include "llvm/IR/Function.h"
@@ -25,6 +27,10 @@
 #include "llvm/IR/Module.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Pass.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include <memory>
@@ -36,25 +42,31 @@ using namespace llvm::PatternMatch;
 
 namespace {
 
-struct HandlerAllocas {
-  TinyPtrVector<AllocaInst *> Allocas;
-  int ParentFrameAllocationIndex;
-};
-
 // This map is used to model frame variable usage during outlining, to
 // construct a structure type to hold the frame variables in a frame
 // allocation block, and to remap the frame variable allocas (including
 // spill locations as needed) to GEPs that get the variable from the
 // frame allocation structure.
-typedef MapVector<AllocaInst *, HandlerAllocas> FrameVarInfoMap;
+typedef MapVector<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap;
 
-class WinEHPrepare : public FunctionPass {
-  std::unique_ptr<FunctionPass> DwarfPrepare;
+typedef SmallSet<BasicBlock *, 4> VisitedBlockSet;
+
+enum ActionType { Catch, Cleanup };
+
+class LandingPadActions;
+class ActionHandler;
+class CatchHandler;
+class CleanupHandler;
+class LandingPadMap;
 
+typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy;
+typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy;
+
+class WinEHPrepare : public FunctionPass {
 public:
   static char ID; // Pass identification, replacement for typeid.
   WinEHPrepare(const TargetMachine *TM = nullptr)
-      : FunctionPass(ID), DwarfPrepare(createDwarfEHPass(TM)) {}
+      : FunctionPass(ID) {}
 
   bool runOnFunction(Function &Fn) override;
 
@@ -67,11 +79,24 @@ public:
   }
 
 private:
-  bool prepareCPPEHHandlers(Function &F,
-                            SmallVectorImpl<LandingPadInst *> &LPads);
-  bool outlineCatchHandler(Function *SrcFn, Constant *SelectorType,
-                           LandingPadInst *LPad, CallInst *&EHAlloc,
-                           AllocaInst *&EHObjPtr, FrameVarInfoMap &VarInfo);
+  bool prepareExceptionHandlers(Function &F,
+                                SmallVectorImpl<LandingPadInst *> &LPads);
+  bool outlineHandler(ActionHandler *Action, Function *SrcFn,
+                      LandingPadInst *LPad, BasicBlock *StartBB,
+                      FrameVarInfoMap &VarInfo);
+
+  void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions);
+  CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB,
+                                 VisitedBlockSet &VisitedBlocks);
+  CleanupHandler *findCleanupHandler(BasicBlock *StartBB, BasicBlock *EndBB);
+
+  void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
+
+  // All fields are reset by runOnFunction.
+  EHPersonality Personality;
+  CatchHandlerMapTy CatchHandlerMap;
+  CleanupHandlerMapTy CleanupHandlerMap;
+  DenseMap<const LandingPadInst *, LandingPadMap>  LPadMaps;
 };
 
 class WinEHFrameVariableMaterializer : public ValueMaterializer {
@@ -87,34 +112,218 @@ private:
   IRBuilder<> Builder;
 };
 
-class WinEHCatchDirector : public CloningDirector {
+class LandingPadMap {
+public:
+  LandingPadMap() : OriginLPad(nullptr) {}
+  void mapLandingPad(const LandingPadInst *LPad);
+
+  bool isInitialized() { return OriginLPad != nullptr; }
+
+  bool mapIfEHPtrLoad(const LoadInst *Load) {
+    return mapIfEHLoad(Load, EHPtrStores, EHPtrStoreAddrs);
+  }
+  bool mapIfSelectorLoad(const LoadInst *Load) {
+    return mapIfEHLoad(Load, SelectorStores, SelectorStoreAddrs);
+  }
+
+  bool isLandingPadSpecificInst(const Instruction *Inst) const;
+
+  void remapSelector(ValueToValueMapTy &VMap, Value *MappedValue) const;
+
+private:
+  bool mapIfEHLoad(const LoadInst *Load,
+                   SmallVectorImpl<const StoreInst *> &Stores,
+                   SmallVectorImpl<const Value *> &StoreAddrs);
+
+  const LandingPadInst *OriginLPad;
+  // We will normally only see one of each of these instructions, but
+  // if more than one occurs for some reason we can handle that.
+  TinyPtrVector<const ExtractValueInst *> ExtractedEHPtrs;
+  TinyPtrVector<const ExtractValueInst *> ExtractedSelectors;
+
+  // In optimized code, there will typically be at most one instance of
+  // each of the following, but in unoptimized IR it is not uncommon
+  // for the values to be stored, loaded and then stored again.  In that
+  // case we will create a second entry for each store and store address.
+  SmallVector<const StoreInst *, 2> EHPtrStores;
+  SmallVector<const StoreInst *, 2> SelectorStores;
+  SmallVector<const Value *, 2> EHPtrStoreAddrs;
+  SmallVector<const Value *, 2> SelectorStoreAddrs;
+};
+
+class WinEHCloningDirectorBase : public CloningDirector {
 public:
-  WinEHCatchDirector(LandingPadInst *LPI, Function *CatchFn, Value *Selector,
-                     Value *EHObj, FrameVarInfoMap &VarInfo)
-      : LPI(LPI), CurrentSelector(Selector->stripPointerCasts()), EHObj(EHObj),
-        Materializer(CatchFn, VarInfo),
-        SelectorIDType(Type::getInt32Ty(LPI->getContext())),
-        Int8PtrType(Type::getInt8PtrTy(LPI->getContext())) {}
+  WinEHCloningDirectorBase(Function *HandlerFn,
+                           FrameVarInfoMap &VarInfo,
+                           LandingPadMap &LPadMap)
+      : Materializer(HandlerFn, VarInfo),
+        SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
+        Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())),
+        LPadMap(LPadMap) {}
 
   CloningAction handleInstruction(ValueToValueMapTy &VMap,
                                   const Instruction *Inst,
                                   BasicBlock *NewBB) override;
 
+  virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
+                                         const Instruction *Inst,
+                                         BasicBlock *NewBB) = 0;
+  virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap,
+                                       const Instruction *Inst,
+                                       BasicBlock *NewBB) = 0;
+  virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
+                                        const Instruction *Inst,
+                                        BasicBlock *NewBB) = 0;
+  virtual CloningAction handleInvoke(ValueToValueMapTy &VMap,
+                                     const InvokeInst *Invoke,
+                                     BasicBlock *NewBB) = 0;
+  virtual CloningAction handleResume(ValueToValueMapTy &VMap,
+                                     const ResumeInst *Resume,
+                                     BasicBlock *NewBB) = 0;
+
   ValueMaterializer *getValueMaterializer() override { return &Materializer; }
 
-private:
-  LandingPadInst *LPI;
-  Value *CurrentSelector;
-  Value *EHObj;
+protected:
   WinEHFrameVariableMaterializer Materializer;
   Type *SelectorIDType;
   Type *Int8PtrType;
+  LandingPadMap &LPadMap;
+};
+
+class WinEHCatchDirector : public WinEHCloningDirectorBase {
+public:
+  WinEHCatchDirector(Function *CatchFn, Value *Selector,
+                     FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
+      : WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap),
+        CurrentSelector(Selector->stripPointerCasts()),
+        ExceptionObjectVar(nullptr) {}
+
+  CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
+                                 const Instruction *Inst,
+                                 BasicBlock *NewBB) override;
+  CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
+                               BasicBlock *NewBB) override;
+  CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
+                                const Instruction *Inst,
+                                BasicBlock *NewBB) override;
+  CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
+                             BasicBlock *NewBB) override;
+  CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
+                             BasicBlock *NewBB) override;
+
+  const Value *getExceptionVar() { return ExceptionObjectVar; }
+  TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
+
+private:
+  Value *CurrentSelector;
 
-  const Value *ExtractedEHPtr;
-  const Value *ExtractedSelector;
-  const Value *EHPtrStoreAddr;
-  const Value *SelectorStoreAddr;
+  const Value *ExceptionObjectVar;
+  TinyPtrVector<BasicBlock *> ReturnTargets;
 };
+
+class WinEHCleanupDirector : public WinEHCloningDirectorBase {
+public:
+  WinEHCleanupDirector(Function *CleanupFn,
+                       FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
+      : WinEHCloningDirectorBase(CleanupFn, VarInfo, LPadMap) {}
+
+  CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
+                                 const Instruction *Inst,
+                                 BasicBlock *NewBB) override;
+  CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
+                               BasicBlock *NewBB) override;
+  CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
+                                const Instruction *Inst,
+                                BasicBlock *NewBB) override;
+  CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
+                             BasicBlock *NewBB) override;
+  CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
+                             BasicBlock *NewBB) override;
+};
+
+class ActionHandler {
+public:
+  ActionHandler(BasicBlock *BB, ActionType Type)
+      : StartBB(BB), Type(Type), HandlerBlockOrFunc(nullptr) {}
+
+  ActionType getType() const { return Type; }
+  BasicBlock *getStartBlock() const { return StartBB; }
+
+  bool hasBeenProcessed() { return HandlerBlockOrFunc != nullptr; }
+
+  void setHandlerBlockOrFunc(Constant *F) { HandlerBlockOrFunc = F; }
+  Constant *getHandlerBlockOrFunc() { return HandlerBlockOrFunc; }
+
+private:
+  BasicBlock *StartBB;
+  ActionType Type;
+
+  // Can be either a BlockAddress or a Function depending on the EH personality.
+  Constant *HandlerBlockOrFunc;
+};
+
+class CatchHandler : public ActionHandler {
+public:
+  CatchHandler(BasicBlock *BB, Constant *Selector, BasicBlock *NextBB)
+      : ActionHandler(BB, ActionType::Catch), Selector(Selector),
+        NextBB(NextBB), ExceptionObjectVar(nullptr) {}
+
+  // Method for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const ActionHandler *H) {
+    return H->getType() == ActionType::Catch;
+  }
+
+  Constant *getSelector() const { return Selector; }
+  BasicBlock *getNextBB() const { return NextBB; }
+
+  const Value *getExceptionVar() { return ExceptionObjectVar; }
+  TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
+
+  void setExceptionVar(const Value *Val) { ExceptionObjectVar = Val; }
+  void setReturnTargets(TinyPtrVector<BasicBlock *> &Targets) {
+    ReturnTargets = Targets;
+  }
+
+private:
+  Constant *Selector;
+  BasicBlock *NextBB;
+  const Value *ExceptionObjectVar;
+  TinyPtrVector<BasicBlock *> ReturnTargets;
+};
+
+class CleanupHandler : public ActionHandler {
+public:
+  CleanupHandler(BasicBlock *BB) : ActionHandler(BB, ActionType::Cleanup) {}
+
+  // Method for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const ActionHandler *H) {
+    return H->getType() == ActionType::Cleanup;
+  }
+};
+
+class LandingPadActions {
+public:
+  LandingPadActions() : HasCleanupHandlers(false) {}
+
+  void insertCatchHandler(CatchHandler *Action) { Actions.push_back(Action); }
+  void insertCleanupHandler(CleanupHandler *Action) {
+    Actions.push_back(Action);
+    HasCleanupHandlers = true;
+  }
+
+  bool includesCleanup() const { return HasCleanupHandlers; }
+
+  SmallVectorImpl<ActionHandler *>::iterator begin() { return Actions.begin(); }
+  SmallVectorImpl<ActionHandler *>::iterator end() { return Actions.end(); }
+
+private:
+  // Note that this class does not own the ActionHandler objects in this vector.
+  // The ActionHandlers are owned by the CatchHandlerMap and CleanupHandlerMap
+  // in the WinEHPrepare class.
+  SmallVector<ActionHandler *, 4> Actions;
+  bool HasCleanupHandlers;
+};
+
 } // end anonymous namespace
 
 char WinEHPrepare::ID = 0;
@@ -125,10 +334,10 @@ FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) {
   return new WinEHPrepare(TM);
 }
 
-static bool isMSVCPersonality(EHPersonality Pers) {
-  return Pers == EHPersonality::MSVC_Win64SEH ||
-         Pers == EHPersonality::MSVC_CXX;
-}
+// FIXME: Remove this once the backend can handle the prepared IR.
+static cl::opt<bool>
+SEHPrepare("sehprepare", cl::Hidden,
+           cl::desc("Prepare functions with SEH personalities"));
 
 bool WinEHPrepare::runOnFunction(Function &Fn) {
   SmallVector<LandingPadInst *, 4> LPads;
@@ -145,60 +354,67 @@ bool WinEHPrepare::runOnFunction(Function &Fn) {
     return false;
 
   // Classify the personality to see what kind of preparation we need.
-  EHPersonality Pers = classifyEHPersonality(LPads.back()->getPersonalityFn());
-
-  // Delegate through to the DWARF pass if this is unrecognized.
-  if (!isMSVCPersonality(Pers))
-    return DwarfPrepare->runOnFunction(Fn);
+  Personality = classifyEHPersonality(LPads.back()->getPersonalityFn());
 
-  // FIXME: This only returns true if the C++ EH handlers were outlined.
-  //        When that code is complete, it should always return whatever
-  //        prepareCPPEHHandlers returns.
-  if (Pers == EHPersonality::MSVC_CXX && prepareCPPEHHandlers(Fn, LPads))
-    return true;
-
-  // FIXME: SEH Cleanups are unimplemented. Replace them with unreachable.
-  if (Resumes.empty())
+  // Do nothing if this is not an MSVC personality.
+  if (!isMSVCEHPersonality(Personality))
     return false;
 
-  for (ResumeInst *Resume : Resumes) {
-    IRBuilder<>(Resume).CreateUnreachable();
-    Resume->eraseFromParent();
+  if (isAsynchronousEHPersonality(Personality) && !SEHPrepare) {
+    // Replace all resume instructions with unreachable.
+    // FIXME: Remove this once the backend can handle the prepared IR.
+    for (ResumeInst *Resume : Resumes) {
+      IRBuilder<>(Resume).CreateUnreachable();
+      Resume->eraseFromParent();
+    }
+    return true;
   }
 
+  // If there were any landing pads, prepareExceptionHandlers will make changes.
+  prepareExceptionHandlers(Fn, LPads);
   return true;
 }
 
 bool WinEHPrepare::doFinalization(Module &M) {
-  return DwarfPrepare->doFinalization(M);
+  return false;
 }
 
-void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
-  DwarfPrepare->getAnalysisUsage(AU);
-}
+void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {}
 
-bool WinEHPrepare::prepareCPPEHHandlers(
+bool WinEHPrepare::prepareExceptionHandlers(
     Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
   // These containers are used to re-map frame variables that are used in
   // outlined catch and cleanup handlers.  They will be populated as the
   // handlers are outlined.
   FrameVarInfoMap FrameVarInfo;
-  SmallVector<CallInst *, 4> HandlerAllocs;
-  SmallVector<AllocaInst *, 4> HandlerEHObjPtrs;
 
   bool HandlersOutlined = false;
 
+  Module *M = F.getParent();
+  LLVMContext &Context = M->getContext();
+
+  // Create a new function to receive the handler contents.
+  PointerType *Int8PtrType = Type::getInt8PtrTy(Context);
+  Type *Int32Type = Type::getInt32Ty(Context);
+  Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions);
+
   for (LandingPadInst *LPad : LPads) {
     // Look for evidence that this landingpad has already been processed.
     bool LPadHasActionList = false;
     BasicBlock *LPadBB = LPad->getParent();
-    for (Instruction &Inst : LPadBB->getInstList()) {
-      // FIXME: Make this an intrinsic.
-      if (auto *Call = dyn_cast<CallInst>(&Inst))
-        if (Call->getCalledFunction()->getName() == "llvm.eh.actions") {
+    for (Instruction &Inst : *LPadBB) {
+      if (auto *IntrinCall = dyn_cast<IntrinsicInst>(&Inst)) {
+        if (IntrinCall->getIntrinsicID() == Intrinsic::eh_actions) {
           LPadHasActionList = true;
           break;
         }
+      }
+      // FIXME: This is here to help with the development of nested landing pad
+      //        outlining.  It should be removed when that is finished.
+      if (isa<UnreachableInst>(Inst)) {
+        LPadHasActionList = true;
+        break;
+      }
     }
 
     // If we've already outlined the handlers for this landingpad,
@@ -206,177 +422,244 @@ bool WinEHPrepare::prepareCPPEHHandlers(
     if (LPadHasActionList)
       continue;
 
-    for (unsigned Idx = 0, NumClauses = LPad->getNumClauses(); Idx < NumClauses;
-         ++Idx) {
-      if (LPad->isCatch(Idx)) {
-        // Create a new instance of the handler data structure in the
-        // HandlerData vector.
-        CallInst *EHAlloc = nullptr;
-        AllocaInst *EHObjPtr = nullptr;
-        bool Outlined = outlineCatchHandler(&F, LPad->getClause(Idx), LPad,
-                                            EHAlloc, EHObjPtr, FrameVarInfo);
-        if (Outlined) {
+    LandingPadActions Actions;
+    mapLandingPadBlocks(LPad, Actions);
+
+    for (ActionHandler *Action : Actions) {
+      if (Action->hasBeenProcessed())
+        continue;
+      BasicBlock *StartBB = Action->getStartBlock();
+
+      // SEH doesn't do any outlining for catches. Instead, pass the handler
+      // basic block addr to llvm.eh.actions and list the block as a return
+      // target.
+      if (isAsynchronousEHPersonality(Personality)) {
+        if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
+          processSEHCatchHandler(CatchAction, StartBB);
           HandlersOutlined = true;
-          // These values must be resolved after all handlers have been
-          // outlined.
-          if (EHAlloc)
-            HandlerAllocs.push_back(EHAlloc);
-          if (EHObjPtr)
-            HandlerEHObjPtrs.push_back(EHObjPtr);
+          continue;
         }
-      } // End if (isCatch)
-    }   // End for each clause
-  }     // End for each landingpad
+      }
+
+      if (outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo)) {
+        HandlersOutlined = true;
+      }
+    } // End for each Action
+
+    // FIXME: We need a guard against partially outlined functions.
+    if (!HandlersOutlined)
+      continue;
+
+    // Replace the landing pad with a new llvm.eh.action based landing pad.
+    BasicBlock *NewLPadBB = BasicBlock::Create(Context, "lpad", &F, LPadBB);
+    assert(!isa<PHINode>(LPadBB->begin()));
+    Instruction *NewLPad = LPad->clone();
+    NewLPadBB->getInstList().push_back(NewLPad);
+    while (!pred_empty(LPadBB)) {
+      auto *pred = *pred_begin(LPadBB);
+      InvokeInst *Invoke = cast<InvokeInst>(pred->getTerminator());
+      Invoke->setUnwindDest(NewLPadBB);
+    }
+
+    // Replace uses of the old lpad in phis with this block and delete the old
+    // block.
+    LPadBB->replaceSuccessorsPhiUsesWith(NewLPadBB);
+    LPadBB->getTerminator()->eraseFromParent();
+    new UnreachableInst(LPadBB->getContext(), LPadBB);
+
+    // Add a call to describe the actions for this landing pad.
+    std::vector<Value *> ActionArgs;
+    for (ActionHandler *Action : Actions) {
+      // Action codes from docs are: 0 cleanup, 1 catch.
+      if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
+        ActionArgs.push_back(ConstantInt::get(Int32Type, 1));
+        ActionArgs.push_back(CatchAction->getSelector());
+        Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar());
+        if (EHObj)
+          ActionArgs.push_back(EHObj);
+        else
+          ActionArgs.push_back(ConstantPointerNull::get(Int8PtrType));
+      } else {
+        ActionArgs.push_back(ConstantInt::get(Int32Type, 0));
+      }
+      ActionArgs.push_back(Action->getHandlerBlockOrFunc());
+    }
+    CallInst *Recover =
+        CallInst::Create(ActionIntrin, ActionArgs, "recover", NewLPadBB);
+
+    // Add an indirect branch listing possible successors of the catch handlers.
+    IndirectBrInst *Branch = IndirectBrInst::Create(Recover, 0, NewLPadBB);
+    for (ActionHandler *Action : Actions) {
+      if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
+        for (auto *Target : CatchAction->getReturnTargets()) {
+          Branch->addDestination(Target);
+        }
+      }
+    }
+  } // End for each landingpad
 
   // If nothing got outlined, there is no more processing to be done.
   if (!HandlersOutlined)
     return false;
 
-  // FIXME: We will replace the landingpad bodies with llvm.eh.actions
-  //        calls and indirect branches here and then delete blocks
-  //        which are no longer reachable.  That will get rid of the
-  //        handlers that we have outlined.  There is code below
-  //        that looks for allocas with no uses in the parent function.
-  //        That will only happen after the pruning is implemented.
-
-  // Remap the frame variables.
-  SmallVector<Type *, 2> StructTys;
-  StructTys.push_back(Type::getInt32Ty(F.getContext()));   // EH state
-  StructTys.push_back(Type::getInt8PtrTy(F.getContext())); // EH object
-
-  // Start the index at two since we always have the above fields at 0 and 1.
-  int Idx = 2;
-
-  // FIXME: Sort the FrameVarInfo vector by the ParentAlloca size and alignment
-  //        and add padding as necessary to provide the proper alignment.
-
-  // Map the alloca instructions to the corresponding index in the
-  // frame allocation structure.  If any alloca is used only in a single
-  // handler and is not used in the parent frame after outlining, it will
-  // be assigned an index of -1, meaning the handler can keep its
-  // "temporary" alloca and the original alloca can be erased from the
-  // parent function.  If we later encounter this alloca in a second
-  // handler, we will assign it a place in the frame allocation structure
-  // at that time.  Since the instruction replacement doesn't happen until
-  // all the entries in the HandlerData have been processed this isn't a
-  // problem.
-  for (auto &VarInfoEntry : FrameVarInfo) {
-    AllocaInst *ParentAlloca = VarInfoEntry.first;
-    HandlerAllocas &AllocaInfo = VarInfoEntry.second;
-
-    // If the instruction still has uses in the parent function or if it is
-    // referenced by more than one handler, add it to the frame allocation
-    // structure.
-    if (ParentAlloca->getNumUses() != 0 || AllocaInfo.Allocas.size() > 1) {
-      Type *VarTy = ParentAlloca->getAllocatedType();
-      StructTys.push_back(VarTy);
-      AllocaInfo.ParentFrameAllocationIndex = Idx++;
-    } else {
-      // If the variable is not used in the parent frame and it is only used
-      // in one handler, the alloca can be removed from the parent frame
-      // and the handler will keep its "temporary" alloca to define the value.
-      // An element index of -1 is used to indicate this condition.
-      AllocaInfo.ParentFrameAllocationIndex = -1;
-    }
-  }
+  // Delete any blocks that were only used by handlers that were outlined above.
+  removeUnreachableBlocks(F);
 
-  // Having filled the StructTys vector and assigned an index to each element,
-  // we can now create the structure.
-  StructType *EHDataStructTy = StructType::create(
-      F.getContext(), StructTys, "struct." + F.getName().str() + ".ehdata");
-  IRBuilder<> Builder(F.getParent()->getContext());
-
-  // Create a frame allocation.
-  Module *M = F.getParent();
-  LLVMContext &Context = M->getContext();
   BasicBlock *Entry = &F.getEntryBlock();
+  IRBuilder<> Builder(F.getParent()->getContext());
   Builder.SetInsertPoint(Entry->getFirstInsertionPt());
-  Function *FrameAllocFn =
-      Intrinsic::getDeclaration(M, Intrinsic::frameallocate);
-  uint64_t EHAllocSize = M->getDataLayout()->getTypeAllocSize(EHDataStructTy);
-  Value *FrameAllocArgs[] = {
-      ConstantInt::get(Type::getInt32Ty(Context), EHAllocSize)};
-  CallInst *FrameAlloc =
-      Builder.CreateCall(FrameAllocFn, FrameAllocArgs, "frame.alloc");
-
-  Value *FrameEHData = Builder.CreateBitCast(
-      FrameAlloc, EHDataStructTy->getPointerTo(), "eh.data");
-
-  // Now visit each handler that is using the structure and bitcast its EHAlloc
-  // value to be a pointer to the frame alloc structure.
-  DenseMap<Function *, Value *> EHDataMap;
-  for (CallInst *EHAlloc : HandlerAllocs) {
-    // The EHAlloc has no uses at this time, so we need to just insert the
-    // cast before the next instruction. There is always a next instruction.
-    BasicBlock::iterator II = EHAlloc;
-    ++II;
-    Builder.SetInsertPoint(cast<Instruction>(II));
-    Value *EHData = Builder.CreateBitCast(
-        EHAlloc, EHDataStructTy->getPointerTo(), "eh.data");
-    EHDataMap[EHAlloc->getParent()->getParent()] = EHData;
-  }
 
-  // Next, replace the place-holder EHObjPtr allocas with GEP instructions
-  // that pull the EHObjPtr from the frame alloc structure
-  for (AllocaInst *EHObjPtr : HandlerEHObjPtrs) {
-    Value *EHData = EHDataMap[EHObjPtr->getParent()->getParent()];
-    Builder.SetInsertPoint(EHObjPtr);
-    Value *ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, 1);
-    EHObjPtr->replaceAllUsesWith(ElementPtr);
-    EHObjPtr->removeFromParent();
-    ElementPtr->takeName(EHObjPtr);
-    delete EHObjPtr;
-  }
+  Function *FrameEscapeFn =
+      Intrinsic::getDeclaration(M, Intrinsic::frameescape);
+  Function *RecoverFrameFn =
+      Intrinsic::getDeclaration(M, Intrinsic::framerecover);
 
   // Finally, replace all of the temporary allocas for frame variables used in
-  // the outlined handlers and the original frame allocas with GEP instructions
-  // that get the equivalent pointer from the frame allocation struct.
+  // the outlined handlers with calls to llvm.framerecover.
+  BasicBlock::iterator II = Entry->getFirstInsertionPt();
+  Instruction *AllocaInsertPt = II;
+  SmallVector<Value *, 8> AllocasToEscape;
   for (auto &VarInfoEntry : FrameVarInfo) {
-    AllocaInst *ParentAlloca = VarInfoEntry.first;
-    HandlerAllocas &AllocaInfo = VarInfoEntry.second;
-    int Idx = AllocaInfo.ParentFrameAllocationIndex;
-
-    // If we have an index of -1 for this instruction, it means it isn't used
-    // outside of this handler.  In that case, we just keep the "temporary"
-    // alloca in the handler and erase the original alloca from the parent.
-    if (Idx == -1) {
+    Value *ParentVal = VarInfoEntry.first;
+    TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
+
+    // If the mapped value isn't already an alloca, we need to spill it if it
+    // is a computed value or copy it if it is an argument.
+    AllocaInst *ParentAlloca = dyn_cast<AllocaInst>(ParentVal);
+    if (!ParentAlloca) {
+      if (auto *Arg = dyn_cast<Argument>(ParentVal)) {
+        // Lower this argument to a copy and then demote that to the stack.
+        // We can't just use the argument location because the handler needs
+        // it to be in the frame allocation block.
+        // Use 'select i8 true, %arg, undef' to simulate a 'no-op' instruction.
+        Value *TrueValue = ConstantInt::getTrue(Context);
+        Value *UndefValue = UndefValue::get(Arg->getType());
+        Instruction *SI =
+            SelectInst::Create(TrueValue, Arg, UndefValue,
+                               Arg->getName() + ".tmp", AllocaInsertPt);
+        Arg->replaceAllUsesWith(SI);
+        // Reset the select operand, because it was clobbered by the RAUW above.
+        SI->setOperand(1, Arg);
+        ParentAlloca = DemoteRegToStack(*SI, true, SI);
+      } else if (auto *PN = dyn_cast<PHINode>(ParentVal)) {
+        ParentAlloca = DemotePHIToStack(PN, AllocaInsertPt);
+      } else {
+        Instruction *ParentInst = cast<Instruction>(ParentVal);
+        // FIXME: This is a work-around to temporarily handle the case where an
+        //        instruction that is only used in handlers is not sunk.
+        //        Without uses, DemoteRegToStack would just eliminate the value.
+        //        This will fail if ParentInst is an invoke.
+        if (ParentInst->getNumUses() == 0) {
+          BasicBlock::iterator InsertPt = ParentInst;
+          ++InsertPt;
+          ParentAlloca =
+              new AllocaInst(ParentInst->getType(), nullptr,
+                             ParentInst->getName() + ".reg2mem", InsertPt);
+          new StoreInst(ParentInst, ParentAlloca, InsertPt);
+        } else {
+          ParentAlloca = DemoteRegToStack(*ParentInst, true, ParentInst);
+        }
+      }
+    }
+
+    // If the parent alloca is no longer used and only one of the handlers used
+    // it, erase the parent and leave the copy in the outlined handler.
+    if (ParentAlloca->getNumUses() == 0 && Allocas.size() == 1) {
       ParentAlloca->eraseFromParent();
-    } else {
-      // Otherwise, we replace the parent alloca and all outlined allocas
-      // which map to it with GEP instructions.
-
-      // First replace the original alloca.
-      Builder.SetInsertPoint(ParentAlloca);
-      Builder.SetCurrentDebugLocation(ParentAlloca->getDebugLoc());
-      Value *ElementPtr =
-          Builder.CreateConstInBoundsGEP2_32(FrameEHData, 0, Idx);
-      ParentAlloca->replaceAllUsesWith(ElementPtr);
-      ParentAlloca->removeFromParent();
-      ElementPtr->takeName(ParentAlloca);
-      delete ParentAlloca;
-
-      // Next replace all outlined allocas that are mapped to it.
-      for (AllocaInst *TempAlloca : AllocaInfo.Allocas) {
-        Value *EHData = EHDataMap[TempAlloca->getParent()->getParent()];
-        // FIXME: Sink this GEP into the blocks where it is used.
-        Builder.SetInsertPoint(TempAlloca);
-        Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
-        ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, Idx);
-        TempAlloca->replaceAllUsesWith(ElementPtr);
-        TempAlloca->removeFromParent();
-        ElementPtr->takeName(TempAlloca);
-        delete TempAlloca;
+      continue;
+    }
+
+    // Add this alloca to the list of things to escape.
+    AllocasToEscape.push_back(ParentAlloca);
+
+    // Next replace all outlined allocas that are mapped to it.
+    for (AllocaInst *TempAlloca : Allocas) {
+      Function *HandlerFn = TempAlloca->getParent()->getParent();
+      // FIXME: Sink this GEP into the blocks where it is used.
+      Builder.SetInsertPoint(TempAlloca);
+      Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
+      Value *RecoverArgs[] = {
+          Builder.CreateBitCast(&F, Int8PtrType, ""),
+          &(HandlerFn->getArgumentList().back()),
+          llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
+      Value *RecoveredAlloca = Builder.CreateCall(RecoverFrameFn, RecoverArgs);
+      // Add a pointer bitcast if the alloca wasn't an i8.
+      if (RecoveredAlloca->getType() != TempAlloca->getType()) {
+        RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8");
+        RecoveredAlloca =
+            Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType());
       }
-    } // end else of if (Idx == -1)
-  }   // End for each FrameVarInfo entry.
+      TempAlloca->replaceAllUsesWith(RecoveredAlloca);
+      TempAlloca->removeFromParent();
+      RecoveredAlloca->takeName(TempAlloca);
+      delete TempAlloca;
+    }
+  } // End for each FrameVarInfo entry.
+
+  // Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry
+  // block.
+  Builder.SetInsertPoint(&F.getEntryBlock().back());
+  Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
+
+  // Insert an alloca for the EH state in the entry block. On x86, we will also
+  // insert stores to update the EH state, but on other ISAs, the runtime does
+  // it for us.
+  // FIXME: This record is different on x86.
+  Type *UnwindHelpTy = Type::getInt64Ty(Context);
+  AllocaInst *UnwindHelp =
+      new AllocaInst(UnwindHelpTy, "unwindhelp", &F.getEntryBlock().front());
+  Builder.CreateStore(llvm::ConstantInt::get(UnwindHelpTy, -2), UnwindHelp);
+  Function *UnwindHelpFn =
+      Intrinsic::getDeclaration(M, Intrinsic::eh_unwindhelp);
+  Builder.CreateCall(UnwindHelpFn,
+                     Builder.CreateBitCast(UnwindHelp, Int8PtrType));
+
+  // Clean up the handler action maps we created for this function
+  DeleteContainerSeconds(CatchHandlerMap);
+  CatchHandlerMap.clear();
+  DeleteContainerSeconds(CleanupHandlerMap);
+  CleanupHandlerMap.clear();
 
   return HandlersOutlined;
 }
 
-bool WinEHPrepare::outlineCatchHandler(Function *SrcFn, Constant *SelectorType,
-                                       LandingPadInst *LPad, CallInst *&EHAlloc,
-                                       AllocaInst *&EHObjPtr,
-                                       FrameVarInfoMap &VarInfo) {
+// This function examines a block to determine whether the block ends with a
+// conditional branch to a catch handler based on a selector comparison.
+// This function is used both by the WinEHPrepare::findSelectorComparison() and
+// WinEHCleanupDirector::handleTypeIdFor().
+static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
+                               Constant *&Selector, BasicBlock *&NextBB) {
+  ICmpInst::Predicate Pred;
+  BasicBlock *TBB, *FBB;
+  Value *LHS, *RHS;
+
+  if (!match(BB->getTerminator(),
+             m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)), TBB, FBB)))
+    return false;
+
+  if (!match(LHS,
+             m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))) &&
+      !match(RHS, m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))))
+    return false;
+
+  if (Pred == CmpInst::ICMP_EQ) {
+    CatchHandler = TBB;
+    NextBB = FBB;
+    return true;
+  }
+
+  if (Pred == CmpInst::ICMP_NE) {
+    CatchHandler = FBB;
+    NextBB = TBB;
+    return true;
+  }
+
+  return false;
+}
+
+bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
+                                  LandingPadInst *LPad, BasicBlock *StartBB,
+                                  FrameVarInfoMap &VarInfo) {
   Module *M = SrcFn->getParent();
   LLVMContext &Context = M->getContext();
 
@@ -385,133 +668,241 @@ bool WinEHPrepare::outlineCatchHandler(Function *SrcFn, Constant *SelectorType,
   std::vector<Type *> ArgTys;
   ArgTys.push_back(Int8PtrType);
   ArgTys.push_back(Int8PtrType);
-  FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
-  Function *CatchHandler = Function::Create(
-      FnType, GlobalVariable::ExternalLinkage, SrcFn->getName() + ".catch", M);
+  Function *Handler;
+  if (Action->getType() == Catch) {
+    FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
+    Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
+                               SrcFn->getName() + ".catch", M);
+  } else {
+    FunctionType *FnType =
+        FunctionType::get(Type::getVoidTy(Context), ArgTys, false);
+    Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
+                               SrcFn->getName() + ".cleanup", M);
+  }
 
   // Generate a standard prolog to setup the frame recovery structure.
   IRBuilder<> Builder(Context);
-  BasicBlock *Entry = BasicBlock::Create(Context, "catch.entry");
-  CatchHandler->getBasicBlockList().push_front(Entry);
+  BasicBlock *Entry = BasicBlock::Create(Context, "entry");
+  Handler->getBasicBlockList().push_front(Entry);
   Builder.SetInsertPoint(Entry);
   Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
 
-  // The outlined handler will be called with the parent's frame pointer as
-  // its second argument. To enable the handler to access variables from
-  // the parent frame, we use that pointer to get locate a special block
-  // of memory that was allocated using llvm.eh.allocateframe for this
-  // purpose.  During the outlining process we will determine which frame
-  // variables are used in handlers and create a structure that maps these
-  // variables into the frame allocation block.
-  //
-  // The frame allocation block also contains an exception state variable
-  // used by the runtime and a pointer to the exception object pointer
-  // which will be filled in by the runtime for use in the handler.
-  Function *RecoverFrameFn =
-      Intrinsic::getDeclaration(M, Intrinsic::framerecover);
-  Value *RecoverArgs[] = {Builder.CreateBitCast(SrcFn, Int8PtrType, ""),
-                          &(CatchHandler->getArgumentList().back())};
-  EHAlloc = Builder.CreateCall(RecoverFrameFn, RecoverArgs, "eh.alloc");
-
-  // This alloca is only temporary.  We'll be replacing it once we know all the
-  // frame variables that need to go in the frame allocation structure.
-  EHObjPtr = Builder.CreateAlloca(Int8PtrType, 0, "eh.obj.ptr");
-
-  // This will give us a raw pointer to the exception object, which
-  // corresponds to the formal parameter of the catch statement.  If the
-  // handler uses this object, we will generate code during the outlining
-  // process to cast the pointer to the appropriate type and deference it
-  // as necessary.  The un-outlined landing pad code represents the
-  // exception object as the result of the llvm.eh.begincatch call.
-  Value *EHObj = Builder.CreateLoad(EHObjPtr, false, "eh.obj");
+  std::unique_ptr<WinEHCloningDirectorBase> Director;
 
   ValueToValueMapTy VMap;
 
-  // FIXME: Map other values referenced in the filter handler.
-
-  WinEHCatchDirector Director(LPad, CatchHandler, SelectorType, EHObj, VarInfo);
+  LandingPadMap &LPadMap = LPadMaps[LPad];
+  if (!LPadMap.isInitialized())
+    LPadMap.mapLandingPad(LPad);
+  if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
+    Constant *Sel = CatchAction->getSelector();
+    Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap));
+    LPadMap.remapSelector(VMap, ConstantInt::get(Type::getInt32Ty(Context), 1));
+  } else {
+    Director.reset(new WinEHCleanupDirector(Handler, VarInfo, LPadMap));
+  }
 
   SmallVector<ReturnInst *, 8> Returns;
-  ClonedCodeInfo InlinedFunctionInfo;
+  ClonedCodeInfo OutlinedFunctionInfo;
+
+  // If the start block contains PHI nodes, we need to map them.
+  BasicBlock::iterator II = StartBB->begin();
+  while (auto *PN = dyn_cast<PHINode>(II)) {
+    bool Mapped = false;
+    // Look for PHI values that we have already mapped (such as the selector).
+    for (Value *Val : PN->incoming_values()) {
+      if (VMap.count(Val)) {
+        VMap[PN] = VMap[Val];
+        Mapped = true;
+      }
+    }
+    // If we didn't find a match for this value, map it as an undef.
+    if (!Mapped) {
+      VMap[PN] = UndefValue::get(PN->getType());
+    }
+    ++II;
+  }
 
-  BasicBlock::iterator II = LPad;
+  // Skip over PHIs and, if applicable, landingpad instructions.
+  II = StartBB->getFirstInsertionPt();
 
-  CloneAndPruneIntoFromInst(CatchHandler, SrcFn, ++II, VMap,
+  CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap,
                             /*ModuleLevelChanges=*/false, Returns, "",
-                            &InlinedFunctionInfo,
-                            SrcFn->getParent()->getDataLayout(), &Director);
+                            &OutlinedFunctionInfo, Director.get());
 
   // Move all the instructions in the first cloned block into our entry block.
   BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry));
   Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList());
   FirstClonedBB->eraseFromParent();
 
+  if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
+    WinEHCatchDirector *CatchDirector =
+        reinterpret_cast<WinEHCatchDirector *>(Director.get());
+    CatchAction->setExceptionVar(CatchDirector->getExceptionVar());
+    CatchAction->setReturnTargets(CatchDirector->getReturnTargets());
+  }
+
+  Action->setHandlerBlockOrFunc(Handler);
+
   return true;
 }
 
-CloningDirector::CloningAction WinEHCatchDirector::handleInstruction(
-    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
-  // Intercept instructions which extract values from the landing pad aggregate.
-  if (auto *Extract = dyn_cast<ExtractValueInst>(Inst)) {
-    if (Extract->getAggregateOperand() == LPI) {
-      assert(Extract->getNumIndices() == 1 &&
-             "Unexpected operation: extracting both landing pad values");
-      assert((*(Extract->idx_begin()) == 0 || *(Extract->idx_begin()) == 1) &&
-             "Unexpected operation: extracting an unknown landing pad element");
-
-      if (*(Extract->idx_begin()) == 0) {
-        // Element 0 doesn't directly corresponds to anything in the WinEH
-        // scheme.
-        // It will be stored to a memory location, then later loaded and finally
-        // the loaded value will be used as the argument to an
-        // llvm.eh.begincatch
-        // call.  We're tracking it here so that we can skip the store and load.
-        ExtractedEHPtr = Inst;
-      } else {
-        // Element 1 corresponds to the filter selector.  We'll map it to 1 for
-        // matching purposes, but it will also probably be stored to memory and
-        // reloaded, so we need to track the instuction so that we can map the
-        // loaded value too.
-        VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
-        ExtractedSelector = Inst;
-      }
-
-      // Tell the caller not to clone this instruction.
-      return CloningDirector::SkipInstruction;
-    }
-    // Other extract value instructions just get cloned.
-    return CloningDirector::CloneInstruction;
+/// This BB must end in a selector dispatch. All we need to do is pass the
+/// handler block to llvm.eh.actions and list it as a possible indirectbr
+/// target.
+void WinEHPrepare::processSEHCatchHandler(CatchHandler *CatchAction,
+                                          BasicBlock *StartBB) {
+  BasicBlock *HandlerBB;
+  BasicBlock *NextBB;
+  Constant *Selector;
+  bool Res = isSelectorDispatch(StartBB, HandlerBB, Selector, NextBB);
+  if (Res) {
+    // If this was EH dispatch, this must be a conditional branch to the handler
+    // block.
+    // FIXME: Handle instructions in the dispatch block. Currently we drop them,
+    // leading to crashes if some optimization hoists stuff here.
+    assert(CatchAction->getSelector() && HandlerBB &&
+           "expected catch EH dispatch");
+  } else {
+    // This must be a catch-all. Split the block after the landingpad.
+    assert(CatchAction->getSelector()->isNullValue() && "expected catch-all");
+    HandlerBB =
+        StartBB->splitBasicBlock(StartBB->getFirstInsertionPt(), "catch.all");
   }
+  CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB));
+  TinyPtrVector<BasicBlock *> Targets(HandlerBB);
+  CatchAction->setReturnTargets(Targets);
+}
 
-  if (auto *Store = dyn_cast<StoreInst>(Inst)) {
-    // Look for and suppress stores of the extracted landingpad values.
-    const Value *StoredValue = Store->getValueOperand();
-    if (StoredValue == ExtractedEHPtr) {
-      EHPtrStoreAddr = Store->getPointerOperand();
-      return CloningDirector::SkipInstruction;
+void LandingPadMap::mapLandingPad(const LandingPadInst *LPad) {
+  // Each instance of this class should only ever be used to map a single
+  // landing pad.
+  assert(OriginLPad == nullptr || OriginLPad == LPad);
+
+  // If the landing pad has already been mapped, there's nothing more to do.
+  if (OriginLPad == LPad)
+    return;
+
+  OriginLPad = LPad;
+
+  // The landingpad instruction returns an aggregate value.  Typically, its
+  // value will be passed to a pair of extract value instructions and the
+  // results of those extracts are often passed to store instructions.
+  // In unoptimized code the stored value will often be loaded and then stored
+  // again.
+  for (auto *U : LPad->users()) {
+    const ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
+    if (!Extract)
+      continue;
+    assert(Extract->getNumIndices() == 1 &&
+           "Unexpected operation: extracting both landing pad values");
+    unsigned int Idx = *(Extract->idx_begin());
+    assert((Idx == 0 || Idx == 1) &&
+           "Unexpected operation: extracting an unknown landing pad element");
+    if (Idx == 0) {
+      // Element 0 doesn't directly corresponds to anything in the WinEH
+      // scheme.
+      // It will be stored to a memory location, then later loaded and finally
+      // the loaded value will be used as the argument to an
+      // llvm.eh.begincatch
+      // call.  We're tracking it here so that we can skip the store and load.
+      ExtractedEHPtrs.push_back(Extract);
+    } else if (Idx == 1) {
+      // Element 1 corresponds to the filter selector.  We'll map it to 1 for
+      // matching purposes, but it will also probably be stored to memory and
+      // reloaded, so we need to track the instuction so that we can map the
+      // loaded value too.
+      ExtractedSelectors.push_back(Extract);
     }
-    if (StoredValue == ExtractedSelector) {
-      SelectorStoreAddr = Store->getPointerOperand();
-      return CloningDirector::SkipInstruction;
+
+    // Look for stores of the extracted values.
+    for (auto *EU : Extract->users()) {
+      if (auto *Store = dyn_cast<StoreInst>(EU)) {
+        if (Idx == 1) {
+          SelectorStores.push_back(Store);
+          SelectorStoreAddrs.push_back(Store->getPointerOperand());
+        } else {
+          EHPtrStores.push_back(Store);
+          EHPtrStoreAddrs.push_back(Store->getPointerOperand());
+        }
+      }
     }
+  }
+}
 
-    // Any other store just gets cloned.
-    return CloningDirector::CloneInstruction;
+bool LandingPadMap::isLandingPadSpecificInst(const Instruction *Inst) const {
+  if (Inst == OriginLPad)
+    return true;
+  for (auto *Extract : ExtractedEHPtrs) {
+    if (Inst == Extract)
+      return true;
+  }
+  for (auto *Extract : ExtractedSelectors) {
+    if (Inst == Extract)
+      return true;
+  }
+  for (auto *Store : EHPtrStores) {
+    if (Inst == Store)
+      return true;
+  }
+  for (auto *Store : SelectorStores) {
+    if (Inst == Store)
+      return true;
+  }
+
+  return false;
+}
+
+void LandingPadMap::remapSelector(ValueToValueMapTy &VMap,
+                                     Value *MappedValue) const {
+  // Remap all selector extract instructions to the specified value.
+  for (auto *Extract : ExtractedSelectors)
+    VMap[Extract] = MappedValue;
+}
+
+bool LandingPadMap::mapIfEHLoad(const LoadInst *Load,
+                                   SmallVectorImpl<const StoreInst *> &Stores,
+                                   SmallVectorImpl<const Value *> &StoreAddrs) {
+  // This makes the assumption that a store we've previously seen dominates
+  // this load instruction.  That might seem like a rather huge assumption,
+  // but given the way that landingpads are constructed its fairly safe.
+  // FIXME: Add debug/assert code that verifies this.
+  const Value *LoadAddr = Load->getPointerOperand();
+  for (auto *StoreAddr : StoreAddrs) {
+    if (LoadAddr == StoreAddr) {
+      // Handle the common debug scenario where this loaded value is stored
+      // to a different location.
+      for (auto *U : Load->users()) {
+        if (auto *Store = dyn_cast<StoreInst>(U)) {
+          Stores.push_back(Store);
+          StoreAddrs.push_back(Store->getPointerOperand());
+        }
+      }
+      return true;
+    }
   }
+  return false;
+}
+
+CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  // If this is one of the boilerplate landing pad instructions, skip it.
+  // The instruction will have already been remapped in VMap.
+  if (LPadMap.isLandingPadSpecificInst(Inst))
+    return CloningDirector::SkipInstruction;
 
   if (auto *Load = dyn_cast<LoadInst>(Inst)) {
     // Look for loads of (previously suppressed) landingpad values.
-    // The EHPtr load can be ignored (it should only be used as
-    // an argument to llvm.eh.begincatch), but the selector value
-    // needs to be mapped to a constant value of 1 to be used to
-    // simplify the branching to always flow to the current handler.
-    const Value *LoadAddr = Load->getPointerOperand();
-    if (LoadAddr == EHPtrStoreAddr) {
-      VMap[Inst] = UndefValue::get(Int8PtrType);
+    // The EHPtr load can be mapped to an undef value as it should only be used
+    // as an argument to llvm.eh.begincatch, but the selector value needs to be
+    // mapped to a constant value of 1.  This value will be used to simplify the
+    // branching to always flow to the current handler.
+    if (LPadMap.mapIfSelectorLoad(Load)) {
+      VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
       return CloningDirector::SkipInstruction;
     }
-    if (LoadAddr == SelectorStoreAddr) {
-      VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
+    if (LPadMap.mapIfEHPtrLoad(Load)) {
+      VMap[Inst] = UndefValue::get(Int8PtrType);
       return CloningDirector::SkipInstruction;
     }
 
@@ -519,108 +910,576 @@ CloningDirector::CloningAction WinEHCatchDirector::handleInstruction(
     return CloningDirector::CloneInstruction;
   }
 
-  if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) {
-    // The argument to the call is some form of the first element of the
-    // landingpad aggregate value, but that doesn't matter.  It isn't used
-    // here.
-    // The return value of this instruction, however, is used to access the
-    // EH object pointer.  We have generated an instruction to get that value
-    // from the EH alloc block, so we can just map to that here.
-    VMap[Inst] = EHObj;
-    return CloningDirector::SkipInstruction;
-  }
-  if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) {
-    auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
-    // It might be interesting to track whether or not we are inside a catch
-    // function, but that might make the algorithm more brittle than it needs
-    // to be.
-
-    // The end catch call can occur in one of two places: either in a
-    // landingpad
-    // block that is part of the catch handlers exception mechanism, or at the
-    // end of the catch block.  If it occurs in a landing pad, we must skip it
-    // and continue so that the landing pad gets cloned.
-    // FIXME: This case isn't fully supported yet and shouldn't turn up in any
-    //        of the test cases until it is.
-    if (IntrinCall->getParent()->isLandingPad())
-      return CloningDirector::SkipInstruction;
-
-    // If an end catch occurs anywhere else the next instruction should be an
-    // unconditional branch instruction that we want to replace with a return
-    // to the the address of the branch target.
-    const BasicBlock *EndCatchBB = IntrinCall->getParent();
-    const TerminatorInst *Terminator = EndCatchBB->getTerminator();
-    const BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
-    assert(Branch && Branch->isUnconditional());
-    assert(std::next(BasicBlock::const_iterator(IntrinCall)) ==
-           BasicBlock::const_iterator(Branch));
-
-    ReturnInst::Create(NewBB->getContext(),
-                       BlockAddress::get(Branch->getSuccessor(0)), NewBB);
-
-    // We just added a terminator to the cloned block.
-    // Tell the caller to stop processing the current basic block so that
-    // the branch instruction will be skipped.
+  // Nested landing pads will be cloned as stubs, with just the
+  // landingpad instruction and an unreachable instruction. When
+  // all landingpads have been outlined, we'll replace this with the
+  // llvm.eh.actions call and indirect branch created when the
+  // landing pad was outlined.
+  if (auto *NestedLPad = dyn_cast<LandingPadInst>(Inst)) {
+    Instruction *NewInst = NestedLPad->clone();
+    if (NestedLPad->hasName())
+      NewInst->setName(NestedLPad->getName());
+    // FIXME: Store this mapping somewhere else also.
+    VMap[NestedLPad] = NewInst;
+    BasicBlock::InstListType &InstList = NewBB->getInstList();
+    InstList.push_back(NewInst);
+    InstList.push_back(new UnreachableInst(NewBB->getContext()));
     return CloningDirector::StopCloningBB;
   }
-  if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) {
-    auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
-    Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
-    // This causes a replacement that will collapse the landing pad CFG based
-    // on the filter function we intend to match.
-    if (Selector == CurrentSelector)
-      VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
-    else
-      VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
-    // Tell the caller not to clone this instruction.
-    return CloningDirector::SkipInstruction;
-  }
+
+  if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
+    return handleInvoke(VMap, Invoke, NewBB);
+
+  if (auto *Resume = dyn_cast<ResumeInst>(Inst))
+    return handleResume(VMap, Resume, NewBB);
+
+  if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
+    return handleBeginCatch(VMap, Inst, NewBB);
+  if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
+    return handleEndCatch(VMap, Inst, NewBB);
+  if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
+    return handleTypeIdFor(VMap, Inst, NewBB);
 
   // Continue with the default cloning behavior.
   return CloningDirector::CloneInstruction;
 }
 
+CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  // The argument to the call is some form of the first element of the
+  // landingpad aggregate value, but that doesn't matter.  It isn't used
+  // here.
+  // The second argument is an outparameter where the exception object will be
+  // stored. Typically the exception object is a scalar, but it can be an
+  // aggregate when catching by value.
+  // FIXME: Leave something behind to indicate where the exception object lives
+  // for this handler. Should it be part of llvm.eh.actions?
+  assert(ExceptionObjectVar == nullptr && "Multiple calls to "
+                                          "llvm.eh.begincatch found while "
+                                          "outlining catch handler.");
+  ExceptionObjectVar = Inst->getOperand(1)->stripPointerCasts();
+  return CloningDirector::SkipInstruction;
+}
+
+CloningDirector::CloningAction
+WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap,
+                                   const Instruction *Inst, BasicBlock *NewBB) {
+  auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
+  // It might be interesting to track whether or not we are inside a catch
+  // function, but that might make the algorithm more brittle than it needs
+  // to be.
+
+  // The end catch call can occur in one of two places: either in a
+  // landingpad block that is part of the catch handlers exception mechanism,
+  // or at the end of the catch block.  If it occurs in a landing pad, we must
+  // skip it and continue so that the landing pad gets cloned.
+  // FIXME: This case isn't fully supported yet and shouldn't turn up in any
+  //        of the test cases until it is.
+  if (IntrinCall->getParent()->isLandingPad())
+    return CloningDirector::SkipInstruction;
+
+  // If an end catch occurs anywhere else the next instruction should be an
+  // unconditional branch instruction that we want to replace with a return
+  // to the the address of the branch target.
+  const BasicBlock *EndCatchBB = IntrinCall->getParent();
+  const TerminatorInst *Terminator = EndCatchBB->getTerminator();
+  const BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
+  assert(Branch && Branch->isUnconditional());
+  assert(std::next(BasicBlock::const_iterator(IntrinCall)) ==
+         BasicBlock::const_iterator(Branch));
+
+  BasicBlock *ContinueLabel = Branch->getSuccessor(0);
+  ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueLabel),
+                     NewBB);
+  ReturnTargets.push_back(ContinueLabel);
+
+  // We just added a terminator to the cloned block.
+  // Tell the caller to stop processing the current basic block so that
+  // the branch instruction will be skipped.
+  return CloningDirector::StopCloningBB;
+}
+
+CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
+  Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
+  // This causes a replacement that will collapse the landing pad CFG based
+  // on the filter function we intend to match.
+  if (Selector == CurrentSelector)
+    VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
+  else
+    VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
+  // Tell the caller not to clone this instruction.
+  return CloningDirector::SkipInstruction;
+}
+
+CloningDirector::CloningAction
+WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap,
+                                 const InvokeInst *Invoke, BasicBlock *NewBB) {
+  return CloningDirector::CloneInstruction;
+}
+
+CloningDirector::CloningAction
+WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap,
+                                 const ResumeInst *Resume, BasicBlock *NewBB) {
+  // Resume instructions shouldn't be reachable from catch handlers.
+  // We still need to handle it, but it will be pruned.
+  BasicBlock::InstListType &InstList = NewBB->getInstList();
+  InstList.push_back(new UnreachableInst(NewBB->getContext()));
+  return CloningDirector::StopCloningBB;
+}
+
+CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  // Catch blocks within cleanup handlers will always be unreachable.
+  // We'll insert an unreachable instruction now, but it will be pruned
+  // before the cloning process is complete.
+  BasicBlock::InstListType &InstList = NewBB->getInstList();
+  InstList.push_back(new UnreachableInst(NewBB->getContext()));
+  return CloningDirector::StopCloningBB;
+}
+
+CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  // Catch blocks within cleanup handlers will always be unreachable.
+  // We'll insert an unreachable instruction now, but it will be pruned
+  // before the cloning process is complete.
+  BasicBlock::InstListType &InstList = NewBB->getInstList();
+  InstList.push_back(new UnreachableInst(NewBB->getContext()));
+  return CloningDirector::StopCloningBB;
+}
+
+CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
+    ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+  // If we encounter a selector comparison while cloning a cleanup handler,
+  // we want to stop cloning immediately.  Anything after the dispatch
+  // will be outlined into a different handler.
+  BasicBlock *CatchHandler;
+  Constant *Selector;
+  BasicBlock *NextBB;
+  if (isSelectorDispatch(const_cast<BasicBlock *>(Inst->getParent()),
+                         CatchHandler, Selector, NextBB)) {
+    ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
+    return CloningDirector::StopCloningBB;
+  }
+  // If eg.typeid.for is called for any other reason, it can be ignored.
+  VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
+  return CloningDirector::SkipInstruction;
+}
+
+CloningDirector::CloningAction WinEHCleanupDirector::handleInvoke(
+    ValueToValueMapTy &VMap, const InvokeInst *Invoke, BasicBlock *NewBB) {
+  // All invokes in cleanup handlers can be replaced with calls.
+  SmallVector<Value *, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
+  // Insert a normal call instruction...
+  CallInst *NewCall =
+      CallInst::Create(const_cast<Value *>(Invoke->getCalledValue()), CallArgs,
+                       Invoke->getName(), NewBB);
+  NewCall->setCallingConv(Invoke->getCallingConv());
+  NewCall->setAttributes(Invoke->getAttributes());
+  NewCall->setDebugLoc(Invoke->getDebugLoc());
+  VMap[Invoke] = NewCall;
+
+  // Insert an unconditional branch to the normal destination.
+  BranchInst::Create(Invoke->getNormalDest(), NewBB);
+
+  // The unwind destination won't be cloned into the new function, so
+  // we don't need to clean up its phi nodes.
+
+  // We just added a terminator to the cloned block.
+  // Tell the caller to stop processing the current basic block.
+  return CloningDirector::StopCloningBB;
+}
+
+CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
+    ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) {
+  ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
+
+  // We just added a terminator to the cloned block.
+  // Tell the caller to stop processing the current basic block so that
+  // the branch instruction will be skipped.
+  return CloningDirector::StopCloningBB;
+}
+
 WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
     Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
     : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
   Builder.SetInsertPoint(&OutlinedFn->getEntryBlock());
-  // FIXME: Do something with the FrameVarMapped so that it is shared across the
-  // function.
 }
 
 Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
-  // If we're asked to materialize an alloca variable, we temporarily
-  // create a matching alloca in the outlined function.  When all the
-  // outlining is complete, we'll collect these into a structure and
-  // replace these temporary allocas with GEPs referencing the frame
-  // allocation block.
+  // If we're asked to materialize a value that is an instruction, we
+  // temporarily create an alloca in the outlined function and add this
+  // to the FrameVarInfo map.  When all the outlining is complete, we'll
+  // collect these into a structure, spilling non-alloca values in the
+  // parent frame as necessary, and replace these temporary allocas with
+  // GEPs referencing the frame allocation block.
+
+  // If the value is an alloca, the mapping is direct.
   if (auto *AV = dyn_cast<AllocaInst>(V)) {
-    AllocaInst *NewAlloca = Builder.CreateAlloca(
-        AV->getAllocatedType(), AV->getArraySize(), AV->getName());
-    FrameVarInfo[AV].Allocas.push_back(NewAlloca);
+    AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone());
+    Builder.Insert(NewAlloca, AV->getName());
+    FrameVarInfo[AV].push_back(NewAlloca);
     return NewAlloca;
   }
 
-// FIXME: Do PHI nodes need special handling?
+  // For other types of instructions or arguments, we need an alloca based on
+  // the value's type and a load of the alloca.  The alloca will be replaced
+  // by a GEP, but the load will stay.  In the parent function, the value will
+  // be spilled to a location in the frame allocation block.
+  if (isa<Instruction>(V) || isa<Argument>(V)) {
+    AllocaInst *NewAlloca =
+        Builder.CreateAlloca(V->getType(), nullptr, "eh.temp.alloca");
+    FrameVarInfo[V].push_back(NewAlloca);
+    LoadInst *NewLoad = Builder.CreateLoad(NewAlloca, V->getName() + ".reload");
+    return NewLoad;
+  }
 
-// FIXME: Are there other cases we can handle better?  GEP, ExtractValue, etc.
+  // Don't materialize other values.
+  return nullptr;
+}
 
-// FIXME: This doesn't work during cloning because it finds an instruction
-//        in the use list that isn't yet part of a basic block.
-#if 0
-  // If we're asked to remap some other instruction, we'll need to
-  // spill it to an alloca variable in the parent function and add a
-  // temporary alloca in the outlined function to be processed as
-  // described above.
-  Instruction *Inst = dyn_cast<Instruction>(V);
-  if (Inst) {
-    AllocaInst *Spill = DemoteRegToStack(*Inst, true);
-    AllocaInst *NewAlloca = Builder.CreateAlloca(Spill->getAllocatedType(),
-                                                 Spill->getArraySize());
-    FrameVarMap[AV] = NewAlloca;
-    return NewAlloca;
+// This function maps the catch and cleanup handlers that are reachable from the
+// specified landing pad. The landing pad sequence will have this basic shape:
+//
+//  <cleanup handler>
+//  <selector comparison>
+//  <catch handler>
+//  <cleanup handler>
+//  <selector comparison>
+//  <catch handler>
+//  <cleanup handler>
+//  ...
+//
+// Any of the cleanup slots may be absent.  The cleanup slots may be occupied by
+// any arbitrary control flow, but all paths through the cleanup code must
+// eventually reach the next selector comparison and no path can skip to a
+// different selector comparisons, though some paths may terminate abnormally.
+// Therefore, we will use a depth first search from the start of any given
+// cleanup block and stop searching when we find the next selector comparison.
+//
+// If the landingpad instruction does not have a catch clause, we will assume
+// that any instructions other than selector comparisons and catch handlers can
+// be ignored.  In practice, these will only be the boilerplate instructions.
+//
+// The catch handlers may also have any control structure, but we are only
+// interested in the start of the catch handlers, so we don't need to actually
+// follow the flow of the catch handlers.  The start of the catch handlers can
+// be located from the compare instructions, but they can be skipped in the
+// flow by following the contrary branch.
+void WinEHPrepare::mapLandingPadBlocks(LandingPadInst *LPad,
+                                       LandingPadActions &Actions) {
+  unsigned int NumClauses = LPad->getNumClauses();
+  unsigned int HandlersFound = 0;
+  BasicBlock *BB = LPad->getParent();
+
+  DEBUG(dbgs() << "Mapping landing pad: " << BB->getName() << "\n");
+
+  if (NumClauses == 0) {
+    // This landing pad contains only cleanup code.
+    CleanupHandler *Action = new CleanupHandler(BB);
+    CleanupHandlerMap[BB] = Action;
+    Actions.insertCleanupHandler(Action);
+    DEBUG(dbgs() << "  Assuming cleanup code in block " << BB->getName()
+                 << "\n");
+    assert(LPad->isCleanup());
+    return;
+  }
+
+  VisitedBlockSet VisitedBlocks;
+
+  while (HandlersFound != NumClauses) {
+    BasicBlock *NextBB = nullptr;
+
+    // See if the clause we're looking for is a catch-all.
+    // If so, the catch begins immediately.
+    if (isa<ConstantPointerNull>(LPad->getClause(HandlersFound))) {
+      // The catch all must occur last.
+      assert(HandlersFound == NumClauses - 1);
+
+      // For C++ EH, check if there is any interesting cleanup code before we
+      // begin the catch. This is important because cleanups cannot rethrow
+      // exceptions but code called from catches can. For SEH, it isn't
+      // important if some finally code before a catch-all is executed out of
+      // line or after recovering from the exception.
+      if (Personality == EHPersonality::MSVC_CXX) {
+        if (auto *CleanupAction = findCleanupHandler(BB, BB)) {
+          //   Add a cleanup entry to the list
+          Actions.insertCleanupHandler(CleanupAction);
+          DEBUG(dbgs() << "  Found cleanup code in block "
+                       << CleanupAction->getStartBlock()->getName() << "\n");
+        }
+      }
+
+      // Add the catch handler to the action list.
+      CatchHandler *Action =
+          new CatchHandler(BB, LPad->getClause(HandlersFound), nullptr);
+      CatchHandlerMap[BB] = Action;
+      Actions.insertCatchHandler(Action);
+      DEBUG(dbgs() << "  Catch all handler at block " << BB->getName() << "\n");
+      ++HandlersFound;
+
+      // Once we reach a catch-all, don't expect to hit a resume instruction.
+      BB = nullptr;
+      break;
+    }
+
+    CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
+    // See if there is any interesting code executed before the dispatch.
+    if (auto *CleanupAction =
+            findCleanupHandler(BB, CatchAction->getStartBlock())) {
+      //   Add a cleanup entry to the list
+      Actions.insertCleanupHandler(CleanupAction);
+      DEBUG(dbgs() << "  Found cleanup code in block "
+                   << CleanupAction->getStartBlock()->getName() << "\n");
+    }
+
+    assert(CatchAction);
+    ++HandlersFound;
+
+    // Add the catch handler to the action list.
+    Actions.insertCatchHandler(CatchAction);
+    DEBUG(dbgs() << "  Found catch dispatch in block "
+                 << CatchAction->getStartBlock()->getName() << "\n");
+
+    // Move on to the block after the catch handler.
+    BB = NextBB;
+  }
+
+  // If we didn't wind up in a catch-all, see if there is any interesting code
+  // executed before the resume.
+  if (auto *CleanupAction = findCleanupHandler(BB, BB)) {
+    //   Add a cleanup entry to the list
+    Actions.insertCleanupHandler(CleanupAction);
+    DEBUG(dbgs() << "  Found cleanup code in block "
+                 << CleanupAction->getStartBlock()->getName() << "\n");
+  }
+
+  // It's possible that some optimization moved code into a landingpad that
+  // wasn't
+  // previously being used for cleanup.  If that happens, we need to execute
+  // that
+  // extra code from a cleanup handler.
+  if (Actions.includesCleanup() && !LPad->isCleanup())
+    LPad->setCleanup(true);
+}
+
+// This function searches starting with the input block for the next
+// block that terminates with a branch whose condition is based on a selector
+// comparison.  This may be the input block.  See the mapLandingPadBlocks
+// comments for a discussion of control flow assumptions.
+//
+CatchHandler *WinEHPrepare::findCatchHandler(BasicBlock *BB,
+                                             BasicBlock *&NextBB,
+                                             VisitedBlockSet &VisitedBlocks) {
+  // See if we've already found a catch handler use it.
+  // Call count() first to avoid creating a null entry for blocks
+  // we haven't seen before.
+  if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
+    CatchHandler *Action = cast<CatchHandler>(CatchHandlerMap[BB]);
+    NextBB = Action->getNextBB();
+    return Action;
   }
-#endif
 
+  // VisitedBlocks applies only to the current search.  We still
+  // need to consider blocks that we've visited while mapping other
+  // landing pads.
+  VisitedBlocks.insert(BB);
+
+  BasicBlock *CatchBlock = nullptr;
+  Constant *Selector = nullptr;
+
+  // If this is the first time we've visited this block from any landing pad
+  // look to see if it is a selector dispatch block.
+  if (!CatchHandlerMap.count(BB)) {
+    if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
+      CatchHandler *Action = new CatchHandler(BB, Selector, NextBB);
+      CatchHandlerMap[BB] = Action;
+      return Action;
+    }
+  }
+
+  // Visit each successor, looking for the dispatch.
+  // FIXME: We expect to find the dispatch quickly, so this will probably
+  //        work better as a breadth first search.
+  for (BasicBlock *Succ : successors(BB)) {
+    if (VisitedBlocks.count(Succ))
+      continue;
+
+    CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks);
+    if (Action)
+      return Action;
+  }
+  return nullptr;
+}
+
+// These are helper functions to combine repeated code from findCleanupHandler.
+static CleanupHandler *createCleanupHandler(CleanupHandlerMapTy &CleanupHandlerMap,
+                                            BasicBlock *BB) {
+  CleanupHandler *Action = new CleanupHandler(BB);
+  CleanupHandlerMap[BB] = Action;
+  return Action;
+}
+
+// This function searches starting with the input block for the next block that
+// contains code that is not part of a catch handler and would not be eliminated
+// during handler outlining.
+//
+CleanupHandler *WinEHPrepare::findCleanupHandler(BasicBlock *StartBB,
+                                                 BasicBlock *EndBB) {
+  // Here we will skip over the following:
+  //
+  // landing pad prolog:
+  //
+  // Unconditional branches
+  //
+  // Selector dispatch
+  //
+  // Resume pattern
+  //
+  // Anything else marks the start of an interesting block
+
+  BasicBlock *BB = StartBB;
+  // Anything other than an unconditional branch will kick us out of this loop
+  // one way or another.
+  while (BB) {
+    // If we've already scanned this block, don't scan it again.  If it is
+    // a cleanup block, there will be an action in the CleanupHandlerMap.
+    // If we've scanned it and it is not a cleanup block, there will be a
+    // nullptr in the CleanupHandlerMap.  If we have not scanned it, there will
+    // be no entry in the CleanupHandlerMap.  We must call count() first to
+    // avoid creating a null entry for blocks we haven't scanned.
+    if (CleanupHandlerMap.count(BB)) {
+      if (auto *Action = CleanupHandlerMap[BB]) {
+        return cast<CleanupHandler>(Action);
+      } else {
+        // Here we handle the case where the cleanup handler map contains a
+        // value for this block but the value is a nullptr.  This means that
+        // we have previously analyzed the block and determined that it did
+        // not contain any cleanup code.  Based on the earlier analysis, we
+        // know the the block must end in either an unconditional branch, a
+        // resume or a conditional branch that is predicated on a comparison
+        // with a selector.  Either the resume or the selector dispatch
+        // would terminate the search for cleanup code, so the unconditional
+        // branch is the only case for which we might need to continue
+        // searching.
+        if (BB == EndBB)
+          return nullptr;
+        BasicBlock *SuccBB;
+        if (!match(BB->getTerminator(), m_UnconditionalBr(SuccBB)))
+          return nullptr;
+        BB = SuccBB;
+        continue;
+      }
+    }
+
+    // Create an entry in the cleanup handler map for this block.  Initially
+    // we create an entry that says this isn't a cleanup block.  If we find
+    // cleanup code, the caller will replace this entry.
+    CleanupHandlerMap[BB] = nullptr;
+
+    TerminatorInst *Terminator = BB->getTerminator();
+
+    // Landing pad blocks have extra instructions we need to accept.
+    LandingPadMap *LPadMap = nullptr;
+    if (BB->isLandingPad()) {
+      LandingPadInst *LPad = BB->getLandingPadInst();
+      LPadMap = &LPadMaps[LPad];
+      if (!LPadMap->isInitialized())
+        LPadMap->mapLandingPad(LPad);
+    }
+
+    // Look for the bare resume pattern:
+    //   %exn2 = load i8** %exn.slot
+    //   %sel2 = load i32* %ehselector.slot
+    //   %lpad.val1 = insertvalue { i8*, i32 } undef, i8* %exn2, 0
+    //   %lpad.val2 = insertvalue { i8*, i32 } %lpad.val1, i32 %sel2, 1
+    //   resume { i8*, i32 } %lpad.val2
+    if (auto *Resume = dyn_cast<ResumeInst>(Terminator)) {
+      InsertValueInst *Insert1 = nullptr;
+      InsertValueInst *Insert2 = nullptr;
+      Value *ResumeVal = Resume->getOperand(0);
+      // If there is only one landingpad, we may use the lpad directly with no
+      // insertions.
+      if (isa<LandingPadInst>(ResumeVal))
+        return nullptr;
+      if (!isa<PHINode>(ResumeVal)) {
+        Insert2 = dyn_cast<InsertValueInst>(ResumeVal);
+        if (!Insert2)
+          return createCleanupHandler(CleanupHandlerMap, BB);
+        Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand());
+        if (!Insert1)
+          return createCleanupHandler(CleanupHandlerMap, BB);
+      }
+      for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
+           II != IE; ++II) {
+        Instruction *Inst = II;
+        if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
+          continue;
+        if (Inst == Insert1 || Inst == Insert2 || Inst == Resume)
+          continue;
+        if (!Inst->hasOneUse() ||
+            (Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) {
+          return createCleanupHandler(CleanupHandlerMap, BB);
+        }
+      }
+      return nullptr;
+    }
+
+    BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
+    if (Branch) {
+      if (Branch->isConditional()) {
+        // Look for the selector dispatch.
+        //   %sel = load i32* %ehselector.slot
+        //   %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
+        //   %matches = icmp eq i32 %sel12, %2
+        //   br i1 %matches, label %catch14, label %eh.resume
+        CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition());
+        if (!Compare || !Compare->isEquality())
+          return createCleanupHandler(CleanupHandlerMap, BB);
+        for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(),
+                                  IE = BB->end();
+             II != IE; ++II) {
+          Instruction *Inst = II;
+          if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
+            continue;
+          if (Inst == Compare || Inst == Branch)
+            continue;
+          if (!Inst->hasOneUse() || (Inst->user_back() != Compare))
+            return createCleanupHandler(CleanupHandlerMap, BB);
+          if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
+            continue;
+          if (!isa<LoadInst>(Inst))
+            return createCleanupHandler(CleanupHandlerMap, BB);
+        }
+        // The selector dispatch block should always terminate our search.
+        assert(BB == EndBB);
+        return nullptr;
+      } else {
+        // Look for empty blocks with unconditional branches.
+        for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(),
+                                  IE = BB->end();
+             II != IE; ++II) {
+          Instruction *Inst = II;
+          if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
+            continue;
+          if (Inst == Branch)
+            continue;
+          if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
+            continue;
+          // Anything else makes this interesting cleanup code.
+          return createCleanupHandler(CleanupHandlerMap, BB);
+        }
+        if (BB == EndBB)
+          return nullptr;
+        // The branch was unconditional.
+        BB = Branch->getSuccessor(0);
+        continue;
+      } // End else of if branch was conditional
+    }   // End if Branch
+
+    // Anything else makes this interesting cleanup code.
+    return createCleanupHandler(CleanupHandlerMap, BB);
+  }
   return nullptr;
 }