This code is dead, what with the new EH model and the auto-upgraders in place.

Delete!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144043 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 639 deletions

diff --git a/lib/CodeGen/DwarfEHPrepare.cpp b/lib/CodeGen/DwarfEHPrepare.cpp
index ed9e409d3e..aa442233e5 100644
--- a/lib/CodeGen/DwarfEHPrepare.cpp
+++ b/lib/CodeGen/DwarfEHPrepare.cpp
@@ -28,98 +28,33 @@
 #include "llvm/Transforms/Utils/SSAUpdater.h"
 using namespace llvm;
 
-STATISTIC(NumLandingPadsSplit,     "Number of landing pads split");
-STATISTIC(NumUnwindsLowered,       "Number of unwind instructions lowered");
-STATISTIC(NumResumesLowered,       "Number of eh.resume calls lowered");
-STATISTIC(NumExceptionValuesMoved, "Number of eh.exception calls moved");
+STATISTIC(NumResumesLowered, "Number of resume calls lowered");
 
 namespace {
   class DwarfEHPrepare : public FunctionPass {
     const TargetMachine *TM;
     const TargetLowering *TLI;
 
-    // The eh.exception intrinsic.
-    Function *ExceptionValueIntrinsic;
-
-    // The eh.selector intrinsic.
-    Function *SelectorIntrinsic;
-
-    // _Unwind_Resume_or_Rethrow or _Unwind_SjLj_Resume call.
-    Constant *URoR;
-
-    // The EH language-specific catch-all type.
-    GlobalVariable *EHCatchAllValue;
-
-    // _Unwind_Resume or the target equivalent.
+    // RewindFunction - _Unwind_Resume or the target equivalent.
     Constant *RewindFunction;
 
-    // We both use and preserve dominator info.
-    DominatorTree *DT;
-
-    // The function we are running on.
-    Function *F;
-
-    // The landing pads for this function.
-    typedef SmallPtrSet<BasicBlock*, 8> BBSet;
-    BBSet LandingPads;
-
-    bool InsertUnwindResumeCalls();
-
-    bool NormalizeLandingPads();
-    bool LowerUnwindsAndResumes();
-    bool MoveExceptionValueCalls();
-
-    Instruction *CreateExceptionValueCall(BasicBlock *BB);
-
-    /// CleanupSelectors - Any remaining eh.selector intrinsic calls which still
-    /// use the "llvm.eh.catch.all.value" call need to convert to using its
-    /// initializer instead.
-    bool CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels);
-
-    bool HasCatchAllInSelector(IntrinsicInst *);
+    bool InsertUnwindResumeCalls(Function &Fn);
 
-    /// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
-    void FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
-                                 SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels);
-
-    /// FindAllURoRInvokes - Find all URoR invokes in the function.
-    void FindAllURoRInvokes(SmallPtrSet<InvokeInst*, 32> &URoRInvokes);
-
-    /// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" or
-    /// "_Unwind_SjLj_Resume" calls. The "unwind" part of these invokes jump to
-    /// a landing pad within the current function. This is a candidate to merge
-    /// the selector associated with the URoR invoke with the one from the
-    /// URoR's landing pad.
-    bool HandleURoRInvokes();
-
-    /// FindSelectorAndURoR - Find the eh.selector call and URoR call associated
-    /// with the eh.exception call. This recursively looks past instructions
-    /// which don't change the EH pointer value, like casts or PHI nodes.
-    bool FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
-                             SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
-                             SmallPtrSet<PHINode*, 32> &SeenPHIs);
-      
   public:
     static char ID; // Pass identification, replacement for typeid.
     DwarfEHPrepare(const TargetMachine *tm) :
       FunctionPass(ID), TM(tm), TLI(TM->getTargetLowering()),
-      ExceptionValueIntrinsic(0), SelectorIntrinsic(0),
-      URoR(0), EHCatchAllValue(0), RewindFunction(0) {
+      RewindFunction(0) {
         initializeDominatorTreePass(*PassRegistry::getPassRegistry());
       }
 
     virtual bool runOnFunction(Function &Fn);
 
-    // getAnalysisUsage - We need the dominator tree for handling URoR.
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addRequired<DominatorTree>();
-      AU.addPreserved<DominatorTree>();
-    }
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const { }
 
     const char *getPassName() const {
       return "Exception handling preparation";
     }
-
   };
 } // end anonymous namespace
 
@@ -129,543 +64,12 @@ FunctionPass *llvm::createDwarfEHPass(const TargetMachine *tm) {
   return new DwarfEHPrepare(tm);
 }
 
-/// HasCatchAllInSelector - Return true if the intrinsic instruction has a
-/// catch-all.
-bool DwarfEHPrepare::HasCatchAllInSelector(IntrinsicInst *II) {
-  if (!EHCatchAllValue) return false;
-
-  unsigned ArgIdx = II->getNumArgOperands() - 1;
-  GlobalVariable *GV = dyn_cast<GlobalVariable>(II->getArgOperand(ArgIdx));
-  return GV == EHCatchAllValue;
-}
-
-/// FindAllCleanupSelectors - Find all eh.selector calls that are clean-ups.
-void DwarfEHPrepare::
-FindAllCleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels,
-                        SmallPtrSet<IntrinsicInst*, 32> &CatchAllSels) {
-  for (Value::use_iterator
-         I = SelectorIntrinsic->use_begin(),
-         E = SelectorIntrinsic->use_end(); I != E; ++I) {
-    IntrinsicInst *II = cast<IntrinsicInst>(*I);
-
-    if (II->getParent()->getParent() != F)
-      continue;
-
-    if (!HasCatchAllInSelector(II))
-      Sels.insert(II);
-    else
-      CatchAllSels.insert(II);
-  }
-}
-
-/// FindAllURoRInvokes - Find all URoR invokes in the function.
-void DwarfEHPrepare::
-FindAllURoRInvokes(SmallPtrSet<InvokeInst*, 32> &URoRInvokes) {
-  for (Value::use_iterator
-         I = URoR->use_begin(),
-         E = URoR->use_end(); I != E; ++I) {
-    if (InvokeInst *II = dyn_cast<InvokeInst>(*I))
-      URoRInvokes.insert(II);
-  }
-}
-
-/// CleanupSelectors - Any remaining eh.selector intrinsic calls which still use
-/// the "llvm.eh.catch.all.value" call need to convert to using its
-/// initializer instead.
-bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
-  if (!EHCatchAllValue) return false;
-
-  if (!SelectorIntrinsic) {
-    SelectorIntrinsic =
-      Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
-    if (!SelectorIntrinsic) return false;
-  }
-
-  bool Changed = false;
-  for (SmallPtrSet<IntrinsicInst*, 32>::iterator
-         I = Sels.begin(), E = Sels.end(); I != E; ++I) {
-    IntrinsicInst *Sel = *I;
-
-    // Index of the "llvm.eh.catch.all.value" variable.
-    unsigned OpIdx = Sel->getNumArgOperands() - 1;
-    GlobalVariable *GV = dyn_cast<GlobalVariable>(Sel->getArgOperand(OpIdx));
-    if (GV != EHCatchAllValue) continue;
-    Sel->setArgOperand(OpIdx, EHCatchAllValue->getInitializer());
-    Changed = true;
-  }
-
-  return Changed;
-}
-
-/// FindSelectorAndURoR - Find the eh.selector call associated with the
-/// eh.exception call. And indicate if there is a URoR "invoke" associated with
-/// the eh.exception call. This recursively looks past instructions which don't
-/// change the EH pointer value, like casts or PHI nodes.
-bool
-DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
-                                    SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
-                                    SmallPtrSet<PHINode*, 32> &SeenPHIs) {
-  bool Changed = false;
-
-  for (Value::use_iterator
-         I = Inst->use_begin(), E = Inst->use_end(); I != E; ++I) {
-    Instruction *II = dyn_cast<Instruction>(*I);
-    if (!II || II->getParent()->getParent() != F) continue;
-    
-    if (IntrinsicInst *Sel = dyn_cast<IntrinsicInst>(II)) {
-      if (Sel->getIntrinsicID() == Intrinsic::eh_selector)
-        SelCalls.insert(Sel);
-    } else if (InvokeInst *Invoke = dyn_cast<InvokeInst>(II)) {
-      if (Invoke->getCalledFunction() == URoR)
-        URoRInvoke = true;
-    } else if (CastInst *CI = dyn_cast<CastInst>(II)) {
-      Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls, SeenPHIs);
-    } else if (PHINode *PN = dyn_cast<PHINode>(II)) {
-      if (SeenPHIs.insert(PN))
-        // Don't process a PHI node more than once.
-        Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls, SeenPHIs);
-    }
-  }
-
-  return Changed;
-}
-
-/// HandleURoRInvokes - Handle invokes of "_Unwind_Resume_or_Rethrow" or
-/// "_Unwind_SjLj_Resume" calls. The "unwind" part of these invokes jump to a
-/// landing pad within the current function. This is a candidate to merge the
-/// selector associated with the URoR invoke with the one from the URoR's
-/// landing pad.
-bool DwarfEHPrepare::HandleURoRInvokes() {
-  if (!EHCatchAllValue) {
-    EHCatchAllValue =
-      F->getParent()->getNamedGlobal("llvm.eh.catch.all.value");
-    if (!EHCatchAllValue) return false;
-  }
-
-  if (!SelectorIntrinsic) {
-    SelectorIntrinsic =
-      Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_selector);
-    if (!SelectorIntrinsic) return false;
-  }
-
-  SmallPtrSet<IntrinsicInst*, 32> Sels;
-  SmallPtrSet<IntrinsicInst*, 32> CatchAllSels;
-  FindAllCleanupSelectors(Sels, CatchAllSels);
-
-  if (!URoR) {
-    URoR = F->getParent()->getFunction("_Unwind_Resume_or_Rethrow");
-    if (!URoR) return CleanupSelectors(CatchAllSels);
-  }
-
-  SmallPtrSet<InvokeInst*, 32> URoRInvokes;
-  FindAllURoRInvokes(URoRInvokes);
-
-  SmallPtrSet<IntrinsicInst*, 32> SelsToConvert;
-
-  for (SmallPtrSet<IntrinsicInst*, 32>::iterator
-         SI = Sels.begin(), SE = Sels.end(); SI != SE; ++SI) {
-    const BasicBlock *SelBB = (*SI)->getParent();
-    for (SmallPtrSet<InvokeInst*, 32>::iterator
-           UI = URoRInvokes.begin(), UE = URoRInvokes.end(); UI != UE; ++UI) {
-      const BasicBlock *URoRBB = (*UI)->getParent();
-      if (DT->dominates(SelBB, URoRBB)) {
-        SelsToConvert.insert(*SI);
-        break;
-      }
-    }
-  }
-
-  bool Changed = false;
-
-  if (Sels.size() != SelsToConvert.size()) {
-    // If we haven't been able to convert all of the clean-up selectors, then
-    // loop through the slow way to see if they still need to be converted.
-    if (!ExceptionValueIntrinsic) {
-      ExceptionValueIntrinsic =
-        Intrinsic::getDeclaration(F->getParent(), Intrinsic::eh_exception);
-      if (!ExceptionValueIntrinsic)
-        return CleanupSelectors(CatchAllSels);
-    }
-
-    for (Value::use_iterator
-           I = ExceptionValueIntrinsic->use_begin(),
-           E = ExceptionValueIntrinsic->use_end(); I != E; ++I) {
-      IntrinsicInst *EHPtr = dyn_cast<IntrinsicInst>(*I);
-      if (!EHPtr || EHPtr->getParent()->getParent() != F) continue;
-
-      bool URoRInvoke = false;
-      SmallPtrSet<IntrinsicInst*, 8> SelCalls;
-      SmallPtrSet<PHINode*, 32> SeenPHIs;
-      Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls, SeenPHIs);
-
-      if (URoRInvoke) {
-        // This EH pointer is being used by an invoke of an URoR instruction and
-        // an eh.selector intrinsic call. If the eh.selector is a 'clean-up', we
-        // need to convert it to a 'catch-all'.
-        for (SmallPtrSet<IntrinsicInst*, 8>::iterator
-               SI = SelCalls.begin(), SE = SelCalls.end(); SI != SE; ++SI)
-          if (!HasCatchAllInSelector(*SI))
-              SelsToConvert.insert(*SI);
-      }
-    }
-  }
-
-  if (!SelsToConvert.empty()) {
-    // Convert all clean-up eh.selectors, which are associated with "invokes" of
-    // URoR calls, into catch-all eh.selectors.
-    Changed = true;
-
-    for (SmallPtrSet<IntrinsicInst*, 8>::iterator
-           SI = SelsToConvert.begin(), SE = SelsToConvert.end();
-         SI != SE; ++SI) {
-      IntrinsicInst *II = *SI;
-
-      // Use the exception object pointer and the personality function
-      // from the original selector.
-      CallSite CS(II);
-      IntrinsicInst::op_iterator I = CS.arg_begin();
-      IntrinsicInst::op_iterator E = CS.arg_end();
-      IntrinsicInst::op_iterator B = prior(E);
-
-      // Exclude last argument if it is an integer.
-      if (isa<ConstantInt>(B)) E = B;
-
-      // Add exception object pointer (front).
-      // Add personality function (next).
-      // Add in any filter IDs (rest).
-      SmallVector<Value*, 8> Args(I, E);
-
-      Args.push_back(EHCatchAllValue->getInitializer()); // Catch-all indicator.
-
-      CallInst *NewSelector =
-        CallInst::Create(SelectorIntrinsic, Args, "eh.sel.catch.all", II);
-
-      NewSelector->setTailCall(II->isTailCall());
-      NewSelector->setAttributes(II->getAttributes());
-      NewSelector->setCallingConv(II->getCallingConv());
-
-      II->replaceAllUsesWith(NewSelector);
-      II->eraseFromParent();
-    }
-  }
-
-  Changed |= CleanupSelectors(CatchAllSels);
-  return Changed;
-}
-
-/// NormalizeLandingPads - Normalize and discover landing pads, noting them
-/// in the LandingPads set.  A landing pad is normal if the only CFG edges
-/// that end at it are unwind edges from invoke instructions. If we inlined
-/// through an invoke we could have a normal branch from the previous
-/// unwind block through to the landing pad for the original invoke.
-/// Abnormal landing pads are fixed up by redirecting all unwind edges to
-/// a new basic block which falls through to the original.
-bool DwarfEHPrepare::NormalizeLandingPads() {
-  bool Changed = false;
-
-  const MCAsmInfo *MAI = TM->getMCAsmInfo();
-  bool usingSjLjEH = MAI->getExceptionHandlingType() == ExceptionHandling::SjLj;
-
-  for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
-    TerminatorInst *TI = I->getTerminator();
-    if (!isa<InvokeInst>(TI))
-      continue;
-    BasicBlock *LPad = TI->getSuccessor(1);
-    // Skip landing pads that have already been normalized.
-    if (LandingPads.count(LPad))
-      continue;
-
-    // Check that only invoke unwind edges end at the landing pad.
-    bool OnlyUnwoundTo = true;
-    bool SwitchOK = usingSjLjEH;
-    for (pred_iterator PI = pred_begin(LPad), PE = pred_end(LPad);
-         PI != PE; ++PI) {
-      TerminatorInst *PT = (*PI)->getTerminator();
-      // The SjLj dispatch block uses a switch instruction. This is effectively
-      // an unwind edge, so we can disregard it here. There will only ever
-      // be one dispatch, however, so if there are multiple switches, one
-      // of them truly is a normal edge, not an unwind edge.
-      if (SwitchOK && isa<SwitchInst>(PT)) {
-        SwitchOK = false;
-        continue;
-      }
-      if (!isa<InvokeInst>(PT) || LPad == PT->getSuccessor(0)) {
-        OnlyUnwoundTo = false;
-        break;
-      }
-    }
-
-    if (OnlyUnwoundTo) {
-      // Only unwind edges lead to the landing pad.  Remember the landing pad.
-      LandingPads.insert(LPad);
-      continue;
-    }
-
-    // At least one normal edge ends at the landing pad.  Redirect the unwind
-    // edges to a new basic block which falls through into this one.
-
-    // Create the new basic block.
-    BasicBlock *NewBB = BasicBlock::Create(F->getContext(),
-                                           LPad->getName() + "_unwind_edge");
-
-    // Insert it into the function right before the original landing pad.
-    LPad->getParent()->getBasicBlockList().insert(LPad, NewBB);
-
-    // Redirect unwind edges from the original landing pad to NewBB.
-    for (pred_iterator PI = pred_begin(LPad), PE = pred_end(LPad); PI != PE; ) {
-      TerminatorInst *PT = (*PI++)->getTerminator();
-      if (isa<InvokeInst>(PT) && PT->getSuccessor(1) == LPad)
-        // Unwind to the new block.
-        PT->setSuccessor(1, NewBB);
-    }
-
-    // If there are any PHI nodes in LPad, we need to update them so that they
-    // merge incoming values from NewBB instead.
-    for (BasicBlock::iterator II = LPad->begin(); isa<PHINode>(II); ++II) {
-      PHINode *PN = cast<PHINode>(II);
-      pred_iterator PB = pred_begin(NewBB), PE = pred_end(NewBB);
-
-      // Check to see if all of the values coming in via unwind edges are the
-      // same.  If so, we don't need to create a new PHI node.
-      Value *InVal = PN->getIncomingValueForBlock(*PB);
-      for (pred_iterator PI = PB; PI != PE; ++PI) {
-        if (PI != PB && InVal != PN->getIncomingValueForBlock(*PI)) {
-          InVal = 0;
-          break;
-        }
-      }
-
-      if (InVal == 0) {
-        // Different unwind edges have different values.  Create a new PHI node
-        // in NewBB.
-        PHINode *NewPN = PHINode::Create(PN->getType(),
-                                         PN->getNumIncomingValues(),
-                                         PN->getName()+".unwind", NewBB);
-        // Add an entry for each unwind edge, using the value from the old PHI.
-        for (pred_iterator PI = PB; PI != PE; ++PI)
-          NewPN->addIncoming(PN->getIncomingValueForBlock(*PI), *PI);
-
-        // Now use this new PHI as the common incoming value for NewBB in PN.
-        InVal = NewPN;
-      }
-
-      // Revector exactly one entry in the PHI node to come from NewBB
-      // and delete all other entries that come from unwind edges.  If
-      // there are both normal and unwind edges from the same predecessor,
-      // this leaves an entry for the normal edge.
-      for (pred_iterator PI = PB; PI != PE; ++PI)
-        PN->removeIncomingValue(*PI);
-      PN->addIncoming(InVal, NewBB);
-    }
-
-    // Add a fallthrough from NewBB to the original landing pad.
-    BranchInst::Create(LPad, NewBB);
-
-    // Now update DominatorTree analysis information.
-    DT->splitBlock(NewBB);
-
-    // Remember the newly constructed landing pad.  The original landing pad
-    // LPad is no longer a landing pad now that all unwind edges have been
-    // revectored to NewBB.
-    LandingPads.insert(NewBB);
-    ++NumLandingPadsSplit;
-    Changed = true;
-  }
-
-  return Changed;
-}
-
-/// LowerUnwinds - Turn unwind instructions into calls to _Unwind_Resume,
-/// rethrowing any previously caught exception.  This will crash horribly
-/// at runtime if there is no such exception: using unwind to throw a new
-/// exception is currently not supported.
-bool DwarfEHPrepare::LowerUnwindsAndResumes() {
-  SmallVector<Instruction*, 16> ResumeInsts;
-
-  for (Function::iterator fi = F->begin(), fe = F->end(); fi != fe; ++fi) {
-    for (BasicBlock::iterator bi = fi->begin(), be = fi->end(); bi != be; ++bi){
-      if (isa<UnwindInst>(bi))
-        ResumeInsts.push_back(bi);
-      else if (CallInst *call = dyn_cast<CallInst>(bi))
-        if (Function *fn = dyn_cast<Function>(call->getCalledValue()))
-          if (fn->getName() == "llvm.eh.resume")
-            ResumeInsts.push_back(bi);
-    }
-  }
-
-  if (ResumeInsts.empty()) return false;
-
-  // Find the rewind function if we didn't already.
-  if (!RewindFunction) {
-    LLVMContext &Ctx = ResumeInsts[0]->getContext();
-    FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
-                                          Type::getInt8PtrTy(Ctx), false);
-    const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
-    RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
-  }
-
-  bool Changed = false;
-
-  for (SmallVectorImpl<Instruction*>::iterator
-         I = ResumeInsts.begin(), E = ResumeInsts.end(); I != E; ++I) {
-    Instruction *RI = *I;
-
-    // Replace the resuming instruction with a call to _Unwind_Resume (or the
-    // appropriate target equivalent).
-
-    llvm::Value *ExnValue;
-    if (isa<UnwindInst>(RI))
-      ExnValue = CreateExceptionValueCall(RI->getParent());
-    else
-      ExnValue = cast<CallInst>(RI)->getArgOperand(0);
-
-    // Create the call...
-    CallInst *CI = CallInst::Create(RewindFunction, ExnValue, "", RI);
-    CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
-
-    // ...followed by an UnreachableInst, if it was an unwind.
-    // Calls to llvm.eh.resume are typically already followed by this.
-    if (isa<UnwindInst>(RI))
-      new UnreachableInst(RI->getContext(), RI);
-
-    if (isa<UnwindInst>(RI))
-      ++NumUnwindsLowered;
-    else
-      ++NumResumesLowered;
-
-    // Nuke the resume instruction.
-    RI->eraseFromParent();
-
-    Changed = true;
-  }
-
-  return Changed;
-}
-
-/// MoveExceptionValueCalls - Ensure that eh.exception is only ever called from
-/// landing pads by replacing calls outside of landing pads with direct use of
-/// a register holding the appropriate value; this requires adding calls inside
-/// all landing pads to initialize the register.  Also, move eh.exception calls
-/// inside landing pads to the start of the landing pad (optional, but may make
-/// things simpler for later passes).
-bool DwarfEHPrepare::MoveExceptionValueCalls() {
-  // If the eh.exception intrinsic is not declared in the module then there is
-  // nothing to do.  Speed up compilation by checking for this common case.
-  if (!ExceptionValueIntrinsic &&
-      !F->getParent()->getFunction(Intrinsic::getName(Intrinsic::eh_exception)))
-    return false;
-
-  bool Changed = false;
-
-  // Move calls to eh.exception that are inside a landing pad to the start of
-  // the landing pad.
-  for (BBSet::const_iterator LI = LandingPads.begin(), LE = LandingPads.end();
-       LI != LE; ++LI) {
-    BasicBlock *LP = *LI;
-    for (BasicBlock::iterator II = LP->getFirstNonPHIOrDbg(), IE = LP->end();
-         II != IE;)
-      if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
-        // Found a call to eh.exception.
-        if (!EI->use_empty()) {
-          // If there is already a call to eh.exception at the start of the
-          // landing pad, then get hold of it; otherwise create such a call.
-          Value *CallAtStart = CreateExceptionValueCall(LP);
-
-          // If the call was at the start of a landing pad then leave it alone.
-          if (EI == CallAtStart)
-            continue;
-          EI->replaceAllUsesWith(CallAtStart);
-        }
-        EI->eraseFromParent();
-        ++NumExceptionValuesMoved;
-        Changed = true;
-      }
-  }
-
-  // Look for calls to eh.exception that are not in a landing pad.  If one is
-  // found, then a register that holds the exception value will be created in
-  // each landing pad, and the SSAUpdater will be used to compute the values
-  // returned by eh.exception calls outside of landing pads.
-  SSAUpdater SSA;
-
-  // Remember where we found the eh.exception call, to avoid rescanning earlier
-  // basic blocks which we already know contain no eh.exception calls.
-  bool FoundCallOutsideLandingPad = false;
-  Function::iterator BB = F->begin();
-  for (Function::iterator BE = F->end(); BB != BE; ++BB) {
-    // Skip over landing pads.
-    if (LandingPads.count(BB))
-      continue;
-
-    for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
-         II != IE; ++II)
-      if (isa<EHExceptionInst>(II)) {
-        SSA.Initialize(II->getType(), II->getName());
-        FoundCallOutsideLandingPad = true;
-        break;
-      }
-
-    if (FoundCallOutsideLandingPad)
-      break;
-  }
-
-  // If all calls to eh.exception are in landing pads then we are done.
-  if (!FoundCallOutsideLandingPad)
-    return Changed;
-
-  // Add a call to eh.exception at the start of each landing pad, and tell the
-  // SSAUpdater that this is the value produced by the landing pad.
-  for (BBSet::iterator LI = LandingPads.begin(), LE = LandingPads.end();
-       LI != LE; ++LI)
-    SSA.AddAvailableValue(*LI, CreateExceptionValueCall(*LI));
-
-  // Now turn all calls to eh.exception that are not in a landing pad into a use
-  // of the appropriate register.
-  for (Function::iterator BE = F->end(); BB != BE; ++BB) {
-    // Skip over landing pads.
-    if (LandingPads.count(BB))
-      continue;
-
-    for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
-         II != IE;)
-      if (EHExceptionInst *EI = dyn_cast<EHExceptionInst>(II++)) {
-        // Found a call to eh.exception, replace it with the value from any
-        // upstream landing pad(s).
-        EI->replaceAllUsesWith(SSA.GetValueAtEndOfBlock(BB));
-        EI->eraseFromParent();
-        ++NumExceptionValuesMoved;
-      }
-  }
-
-  return true;
-}
-
-/// CreateExceptionValueCall - Insert a call to the eh.exception intrinsic at
-/// the start of the basic block (unless there already is one, in which case
-/// the existing call is returned).
-Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
-  Instruction *Start = BB->getFirstNonPHIOrDbg();
-  // Is this a call to eh.exception?
-  if (IntrinsicInst *CI = dyn_cast<IntrinsicInst>(Start))
-    if (CI->getIntrinsicID() == Intrinsic::eh_exception)
-      // Reuse the existing call.
-      return Start;
-
-  // Find the eh.exception intrinsic if we didn't already.
-  if (!ExceptionValueIntrinsic)
-    ExceptionValueIntrinsic = Intrinsic::getDeclaration(F->getParent(),
-                                                       Intrinsic::eh_exception);
-
-  // Create the call.
-  return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
-}
-
 /// InsertUnwindResumeCalls - Convert the ResumeInsts that are still present
 /// into calls to the appropriate _Unwind_Resume function.
-bool DwarfEHPrepare::InsertUnwindResumeCalls() {
+bool DwarfEHPrepare::InsertUnwindResumeCalls(Function &Fn) {
   bool UsesNewEH = false;
   SmallVector<ResumeInst*, 16> Resumes;
-  for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I) {
+  for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I) {
     TerminatorInst *TI = I->getTerminator();
     if (ResumeInst *RI = dyn_cast<ResumeInst>(TI))
       Resumes.push_back(RI);
@@ -682,18 +86,17 @@ bool DwarfEHPrepare::InsertUnwindResumeCalls() {
     FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
                                           Type::getInt8PtrTy(Ctx), false);
     const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
-    RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
+    RewindFunction = Fn.getParent()->getOrInsertFunction(RewindName, FTy);
   }
 
   // Create the basic block where the _Unwind_Resume call will live.
-  LLVMContext &Ctx = F->getContext();
-  BasicBlock *UnwindBB = BasicBlock::Create(Ctx, "unwind_resume", F);
+  LLVMContext &Ctx = Fn.getContext();
+  BasicBlock *UnwindBB = BasicBlock::Create(Ctx, "unwind_resume", &Fn);
   PHINode *PN = PHINode::Create(Type::getInt8PtrTy(Ctx), Resumes.size(),
                                 "exn.obj", UnwindBB);
 
   // Extract the exception object from the ResumeInst and add it to the PHI node
   // that feeds the _Unwind_Resume call.
-  BasicBlock *UnwindBBDom = Resumes[0]->getParent();
   for (SmallVectorImpl<ResumeInst*>::iterator
          I = Resumes.begin(), E = Resumes.end(); I != E; ++I) {
     ResumeInst *RI = *I;
@@ -701,8 +104,8 @@ bool DwarfEHPrepare::InsertUnwindResumeCalls() {
     ExtractValueInst *ExnObj = ExtractValueInst::Create(RI->getOperand(0),
                                                         0, "exn.obj", RI);
     PN->addIncoming(ExnObj, RI->getParent());
-    UnwindBBDom = DT->findNearestCommonDominator(RI->getParent(), UnwindBBDom);
     RI->eraseFromParent();
+    ++NumResumesLowered;
   }
 
   // Call the function.
@@ -711,40 +114,10 @@ bool DwarfEHPrepare::InsertUnwindResumeCalls() {
 
   // We never expect _Unwind_Resume to return.
   new UnreachableInst(Ctx, UnwindBB);
-
-  // Now update DominatorTree analysis information.
-  DT->addNewBlock(UnwindBB, UnwindBBDom);
   return true;
 }
 
 bool DwarfEHPrepare::runOnFunction(Function &Fn) {
-  bool Changed = false;
-
-  // Initialize internal state.
-  DT = &getAnalysis<DominatorTree>(); // FIXME: We won't need this with the new EH.
-  F = &Fn;
-
-  if (InsertUnwindResumeCalls()) {
-    // FIXME: The reset of this function can go once the new EH is done.
-    LandingPads.clear();
-    return true;
-  }
-
-  // Ensure that only unwind edges end at landing pads (a landing pad is a
-  // basic block where an invoke unwind edge ends).
-  Changed |= NormalizeLandingPads();
-
-  // Turn unwind instructions and eh.resume calls into libcalls.
-  Changed |= LowerUnwindsAndResumes();
-
-  // TODO: Move eh.selector calls to landing pads and combine them.
-
-  // Move eh.exception calls to landing pads.
-  Changed |= MoveExceptionValueCalls();
-
-  Changed |= HandleURoRInvokes();
-
-  LandingPads.clear();
-
+  bool Changed = InsertUnwindResumeCalls(Fn);
   return Changed;
 }