[WinEH] Calculate state numbers for the new EH representation

[majnemer]

Summary

State numbers are calculated by performing a walk from the innermost
funclet to the outermost funclet. Rudimentary support for the new EH
constructs has been added to the assembly printer, just enough to test
the new machinery.

[JosephTremoulet]

LGTM, though I'm less familiar with this part of the code. A few nits/questions inline, but all just minor take-it-or-leave-it suggestions.

lib/CodeGen/AsmPrinter/WinException.cpp

185–188 ↗

(On Diff #32388)

Nit: I don't understand this change; the function will fail if you pass it a non-null non-GlobalValue Value, so to me it seems less error prone to type the parameter as GlobalValue and force callers to recognize the need to downcast.

lib/CodeGen/WinEHPrepare.cpp

2581 ↗

(On Diff #32388)

Nit: const_cast is unfortunate. Would it be horrible to push constness down or non-constness up? (I'm not familiar with the callers/callees imposing the restrictions here)

2949–2958 ↗

(On Diff #32388)

Nit: this was a confusing read because it's not getting the unwind pred of BB, it's getting the unwind pred of a successor of BB. I think it would be easier to read if the parameter name were PredBB and/or a comment explained.

3344 ↗

(On Diff #32388)

I don't understand this change, is there some style guideline against periods ending comments? The other comments in the file tend to have them, and this one is even a full sentence.

[rnk]

Much excitement. :)

lib/CodeGen/AsmPrinter/WinException.cpp

185–188 ↗

(On Diff #32388)

Right, the intent is for the assertion to fail at this point once we start passing such values through. Previously, we outlined funclets in IR, and the IR function was the GlobalValue that we passed through. With the new representation, we are passing a BasicBlock, which inherits from Value. We can't actually reach this code today because SDAGBuilder can't select our new pad instructions yet. Eventually we will get here, the assertion will fail, and we'll fix it up and give it the correct BasicBlock type.

lib/CodeGen/WinEHPrepare.cpp

2581 ↗

(On Diff #32388)

Pushing it down is the right thing in this case. The unwind map lives through codegen, and there shouldn't be non-const IR pointers hanging around during codegen.

2949–2958 ↗

(On Diff #32388)

I guess it really does the following:

Given BB which ends in an unwind edge, return the EHPad that this BB belongs to. If the unwind edge came from an invoke, return null.

Call it getEHPadFromPredecessor?

3284 ↗

(On Diff #32388)

Also left over from hurried pair programming. :)

lib/Target/X86/X86WinEHState.cpp

400–405 ↗

(On Diff #32388)

Probably worth commenting that we only ever create our own WinEHFuncInfo for testing purposes. MMI is non-null iff we are running as part of a CodeGen pass manager.

Given that it's for testing only... we should heap allocate it with something like this:

// If MMI is null, create our own WinEHFuncInfo. This only happens in opt tests.
std::unique_ptr<WinEHFuncInfo> FuncInfoPtr;
if (!MMI)
  FuncInfoPtr.reset(new WinEHFuncInfo());
WinEHFuncInfo &FuncInfo = *(MMI ? &MMI->getWinEHFuncInfo(&F) : FuncInfoPtr.get());

496–501 ↗

(On Diff #32388)

Both of these functions only consume WinEHFuncInfo. We should hoist this logic up to runOnFunction and only pass down WinEHFuncInfo.

[majnemer]

Address review comments.

[JosephTremoulet]

LGTM, thanks.

[rnk]

lgtm

include/llvm/CodeGen/WinEHFuncInfo.h

125 ↗

(On Diff #32430)

This guy should be const. I'm reasonably confident that the const cascading will stop there, since all we use it for is to get an MCSymbol.

lib/CodeGen/WinEHPrepare.cpp

2611 ↗

(On Diff #32430)

We should kill this const_cast too.

[ivladak]

Could you please explain why you

initializeWinEHStatePassPass(PR);

in LLVMInitializeX86Target() regardless of whether the target is win32 or not?

Sorry if the question is silly. I actually have NFC about what's going on in this commit.

I am getting some nasty memory corruption problems which might or might not be caused by this unconditional initialization.

[rnk]

We have no idea at initialization time if the user wants to target win32 or
the host, so we couldn't conditionalize it if we wanted to.

We initialize the pass so that we can run it from opt and test it in
isolation. It's consistent what NVPTX does in
llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp. We just copied the technique.

llvm/trunk/include/llvm/CodeGen/WinEHFuncInfo.h

 void parseEHActions(const IntrinsicInst *II,
                     SmallVectorImpl<std::unique_ptr<ActionHandler>> &Actions);
 
 // The following structs respresent the .xdata for functions using C++
 // exceptions on Windows.
 
 struct WinEHUnwindMapEntry {
   int ToState;
-  Function *Cleanup;
+  const Value *Cleanup;
 };
 
 struct WinEHHandlerType {
   int Adjectives;
   GlobalVariable *TypeDescriptor;
   int CatchObjRecoverIdx;
-  Function *Handler;
+  const Value *Handler;
 };
 
 struct WinEHTryBlockMapEntry {
   int TryLow;
   int TryHigh;
+  int CatchHigh = -1;
   SmallVector<WinEHHandlerType, 1> HandlerArray;
 };
 
 struct WinEHFuncInfo {
   DenseMap<const Function *, const LandingPadInst *> RootLPad;
   DenseMap<const Function *, const InvokeInst *> LastInvoke;
   DenseMap<const Function *, int> HandlerEnclosedState;
   DenseMap<const Function *, bool> LastInvokeVisited;
-  DenseMap<const LandingPadInst *, int> LandingPadStateMap;
+  DenseMap<const Instruction *, int> EHPadStateMap;
   DenseMap<const Function *, int> CatchHandlerParentFrameObjIdx;
   DenseMap<const Function *, int> CatchHandlerParentFrameObjOffset;
   DenseMap<const Function *, int> CatchHandlerMaxState;
   DenseMap<const Function *, int> HandlerBaseState;
   SmallVector<WinEHUnwindMapEntry, 4> UnwindMap;
   SmallVector<WinEHTryBlockMapEntry, 4> TryBlockMap;
   SmallVector<std::pair<MCSymbol *, int>, 4> IPToStateList;
   int UnwindHelpFrameIdx = INT_MAX;
   int UnwindHelpFrameOffset = -1;
   unsigned NumIPToStateFuncsVisited = 0;
 
+  int getLastStateNumber() const { return UnwindMap.size() - 1; }
+
   /// localescape index of the 32-bit EH registration node. Set by
   /// WinEHStatePass and used indirectly by SEH filter functions of the parent.
   int EHRegNodeEscapeIndex = INT_MAX;
 
   WinEHFuncInfo() {}
 };
 
 /// Analyze the IR in ParentFn and it's handlers to build WinEHFuncInfo, which
 /// describes the state numbers and tables used by __CxxFrameHandler3. This
 /// analysis assumes that WinEHPrepare has already been run.
 void calculateWinCXXEHStateNumbers(const Function *ParentFn,
                                    WinEHFuncInfo &FuncInfo);
 
 }
 #endif // LLVM_CODEGEN_WINEHFUNCINFO_H

llvm/trunk/lib/CodeGen/AsmPrinter/WinException.h

 
 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
 #define LLVM_LIB_CODEGEN_ASMPRINTER_WIN64EXCEPTION_H
 
 #include "EHStreamer.h"
 
 namespace llvm {
 class Function;
-class GlobalValue;
 class MachineFunction;
 class MCExpr;
+class Value;
 struct WinEHFuncInfo;
 
 class LLVM_LIBRARY_VISIBILITY WinException : public EHStreamer {
   /// Per-function flag to indicate if personality info should be emitted.
   bool shouldEmitPersonality = false;
 
   /// Per-function flag to indicate if the LSDA should be emitted.
   bool shouldEmitLSDA = false;
void extendIP2StateTable(const MachineFunction *MF, const Function *ParentF,
                            WinEHFuncInfo &FuncInfo);
 
   /// Emits the label used with llvm.x86.seh.recoverfp, which is used by
   /// outlined funclets.
   void emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
                                      StringRef FLinkageName);
 
   const MCExpr *create32bitRef(const MCSymbol *Value);
-  const MCExpr *create32bitRef(const GlobalValue *GV);
+  const MCExpr *create32bitRef(const Value *V);
 
 public:
   //===--------------------------------------------------------------------===//
   // Main entry points.
   //
   WinException(AsmPrinter *A);
   ~WinException() override;
 

llvm/trunk/lib/CodeGen/AsmPrinter/WinException.cpp

const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
   if (!Value)
     return MCConstantExpr::create(0, Asm->OutContext);
   return MCSymbolRefExpr::create(Value, useImageRel32
                                             ? MCSymbolRefExpr::VK_COFF_IMGREL32
                                             : MCSymbolRefExpr::VK_None,
                                  Asm->OutContext);
 }
 
-const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
-  if (!GV)
+const MCExpr *WinException::create32bitRef(const Value *V) {
+  if (!V)
     return MCConstantExpr::create(0, Asm->OutContext);
-  return create32bitRef(Asm->getSymbol(GV));
+  return create32bitRef(Asm->getSymbol(cast<GlobalValue>(V)));
 }
 
 /// Emit the language-specific data that __C_specific_handler expects.  This
 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
 /// up after faults with __try, __except, and __finally.  The typeinfo values
 /// are not really RTTI data, but pointers to filter functions that return an
 /// integer (1, 0, or -1) indicating how to handle the exception. For __finally
 /// blocks and other cleanups, the landing pad label is zero, and the filter
for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
                                                   .concat("$")
                                                   .concat(ParentLinkageName));
 
       HandlerMaps.push_back(HandlerMapXData);
 
       int CatchHigh = -1;
       for (WinEHHandlerType &HT : TBME.HandlerArray)
         CatchHigh =
-            std::max(CatchHigh, FuncInfo.CatchHandlerMaxState[HT.Handler]);
+            std::max(CatchHigh,
+                     FuncInfo.CatchHandlerMaxState[cast<Function>(HT.Handler)]);
 
       assert(TBME.TryLow <= TBME.TryHigh);
       OS.EmitIntValue(TBME.TryLow, 4);                    // TryLow
       OS.EmitIntValue(TBME.TryHigh, 4);                   // TryHigh
       OS.EmitIntValue(CatchHigh, 4);                      // CatchHigh
       OS.EmitIntValue(TBME.HandlerArray.size(), 4);       // NumCatches
       OS.EmitValue(create32bitRef(HandlerMapXData), 4);   // HandlerArray
     }

llvm/trunk/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp

void FunctionLoweringInfo::set(const Function &fn, MachineFunction &mf,
 
   // Copy the state numbers to LandingPadInfo for the current function, which
   // could be a handler or the parent. This should happen for 32-bit SEH and
   // C++ EH.
   if (Personality == EHPersonality::MSVC_CXX ||
       Personality == EHPersonality::MSVC_X86SEH) {
     for (const LandingPadInst *LP : LPads) {
       MachineBasicBlock *LPadMBB = MBBMap[LP->getParent()];
-      MMI.addWinEHState(LPadMBB, EHInfo.LandingPadStateMap[LP]);
+      MMI.addWinEHState(LPadMBB, EHInfo.EHPadStateMap[LP]);
     }
   }
 }
 
 void FunctionLoweringInfo::addSEHHandlersForLPads(
     ArrayRef<const LandingPadInst *> LPads) {
   MachineModuleInfo &MMI = MF->getMMI();
 

llvm/trunk/lib/CodeGen/WinEHPrepare.cpp

struct WinEHNumbering {
   void processCallSite(MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
                        ImmutableCallSite CS);
   void popUnmatchedActions(int FirstMismatch);
   void calculateStateNumbers(const Function &F);
   void findActionRootLPads(const Function &F);
 };
 }
 
-void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
+static int addUnwindMapEntry(WinEHFuncInfo &FuncInfo, int ToState,
+                             const Value *V) {
   WinEHUnwindMapEntry UME;
   UME.ToState = ToState;
-  if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
-    UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc());
-  else
-    UME.Cleanup = nullptr;
+  UME.Cleanup = V;
   FuncInfo.UnwindMap.push_back(UME);
+  return FuncInfo.getLastStateNumber();
+}
+
+static void addTryBlockMapEntry(WinEHFuncInfo &FuncInfo, int TryLow,
+                                int TryHigh, int CatchHigh,
+                                ArrayRef<const CatchPadInst *> Handlers) {
+  WinEHTryBlockMapEntry TBME;
+  TBME.TryLow = TryLow;
+  TBME.TryHigh = TryHigh;
+  TBME.CatchHigh = CatchHigh;
+  assert(TBME.TryLow <= TBME.TryHigh);
+  for (const CatchPadInst *CPI : Handlers) {
+    WinEHHandlerType HT;
+    Constant *TypeInfo = cast<Constant>(CPI->getArgOperand(0));
+    if (TypeInfo->isNullValue()) {
+      HT.Adjectives = 0x40;
+      HT.TypeDescriptor = nullptr;
+    } else {
+      auto *GV = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
+      // Selectors are always pointers to GlobalVariables with 'struct' type.
+      // The struct has two fields, adjectives and a type descriptor.
+      auto *CS = cast<ConstantStruct>(GV->getInitializer());
+      HT.Adjectives =
+          cast<ConstantInt>(CS->getAggregateElement(0U))->getZExtValue();
+      HT.TypeDescriptor =
+          cast<GlobalVariable>(CS->getAggregateElement(1)->stripPointerCasts());
+    }
+    HT.Handler = CPI->getParent();
+    // FIXME: Pass CPI->getArgOperand(1).
+    HT.CatchObjRecoverIdx = -1;
+    TBME.HandlerArray.push_back(HT);
+  }
+  FuncInfo.TryBlockMap.push_back(TBME);
+}
+
+void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
+  Value *V = nullptr;
+  if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
+    V = cast<Function>(CH->getHandlerBlockOrFunc());
+  addUnwindMapEntry(FuncInfo, ToState, V);
 }
 
 void WinEHNumbering::createTryBlockMapEntry(int TryLow, int TryHigh,
                                             ArrayRef<CatchHandler *> Handlers) {
   // See if we already have an entry for this set of handlers.
   // This is using iterators rather than a range-based for loop because
   // if we find the entry we're looking for we'll need the iterator to erase it.
   int NumHandlers = Handlers.size();
for (const BasicBlock &BB : F) {
     auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
     if (!ActionsCall)
       continue;
     parseEHActions(ActionsCall, ActionList);
     if (ActionList.empty())
       continue;
     processCallSite(ActionList, II);
     ActionList.clear();
-    FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
+    FuncInfo.EHPadStateMap[LPI] = currentEHNumber();
     DEBUG(dbgs() << "Assigning state " << currentEHNumber()
                   << " to landing pad at " << LPI->getParent()->getName()
                   << '\n');
   }
 
   // Pop any actions that were pushed on the stack for this function.
   popUnmatchedActions(SavedHandlerStackSize);
 
for (const BasicBlock &BB : F) {
     for (int I = 0, E = ActionList.size(); I < E; ++I)
       if (auto *Handler
               = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc()))
         findActionRootLPads(*Handler);
     ActionList.clear();
   }
 }
 
+static const BasicBlock *getSingleCatchPadPredecessor(const BasicBlock &BB) {
+  for (const BasicBlock *PredBlock : predecessors(&BB))
+    if (isa<CatchPadInst>(PredBlock->getFirstNonPHI()))
+      return PredBlock;
+  return nullptr;
+}
+
+// Given BB which ends in an unwind edge, return the EHPad that this BB belongs
+// to. If the unwind edge came from an invoke, return null.
+static const BasicBlock *getEHPadFromPredecessor(const BasicBlock *BB) {
+  const TerminatorInst *TI = BB->getTerminator();
+  if (isa<InvokeInst>(TI))
+    return nullptr;
+  if (isa<CatchPadInst>(TI) || isa<CatchEndPadInst>(TI) ||
+      isa<TerminatePadInst>(TI))
+    return BB;
+  return cast<CleanupPadInst>(cast<CleanupReturnInst>(TI)->getReturnValue())
+      ->getParent();
+}
+
+static void calculateExplicitStateNumbers(WinEHFuncInfo &FuncInfo,
+                                          const BasicBlock &BB,
+                                          int ParentState) {
+  assert(BB.isEHPad());
+  const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+  // All catchpad instructions will be handled when we process their
+  // respective catchendpad instruction.
+  if (isa<CatchPadInst>(FirstNonPHI))
+    return;
+
+  if (isa<CatchEndPadInst>(FirstNonPHI)) {
+    const BasicBlock *TryPad = &BB;
+    const BasicBlock *LastTryPad = nullptr;
+    SmallVector<const CatchPadInst *, 2> Handlers;
+    do {
+      LastTryPad = TryPad;
+      TryPad = getSingleCatchPadPredecessor(*TryPad);
+      if (TryPad)
+        Handlers.push_back(cast<CatchPadInst>(TryPad->getFirstNonPHI()));
+    } while (TryPad);
+    // We've pushed these back into reverse source order.  Reverse them to get
+    // the list back into source order.
+    std::reverse(Handlers.begin(), Handlers.end());
+    int TryLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr);
+    FuncInfo.EHPadStateMap[Handlers.front()] = TryLow;
+    for (const BasicBlock *PredBlock : predecessors(LastTryPad))
+      if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+        calculateExplicitStateNumbers(FuncInfo, *PredBlock, TryLow);
+    int CatchLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr);
+    FuncInfo.EHPadStateMap[FirstNonPHI] = CatchLow;
+    int TryHigh = CatchLow - 1;
+    for (const BasicBlock *PredBlock : predecessors(&BB))
+      if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+        calculateExplicitStateNumbers(FuncInfo, *PredBlock, CatchLow);
+    int CatchHigh = FuncInfo.getLastStateNumber();
+    addTryBlockMapEntry(FuncInfo, TryLow, TryHigh, CatchHigh, Handlers);
+    DEBUG(dbgs() << "TryLow[" << LastTryPad->getName() << "]: " << TryLow
+                 << '\n');
+    DEBUG(dbgs() << "TryHigh[" << LastTryPad->getName() << "]: " << TryHigh
+                 << '\n');
+    DEBUG(dbgs() << "CatchHigh[" << LastTryPad->getName() << "]: " << CatchHigh
+                 << '\n');
+  } else if (isa<CleanupPadInst>(FirstNonPHI)) {
+    int CleanupState = addUnwindMapEntry(FuncInfo, ParentState, &BB);
+    FuncInfo.EHPadStateMap[FirstNonPHI] = CleanupState;
+    DEBUG(dbgs() << "Assigning state #" << CleanupState << " to BB "
+                 << BB.getName() << '\n');
+    for (const BasicBlock *PredBlock : predecessors(&BB))
+      if ((PredBlock = getEHPadFromPredecessor(PredBlock)))
+        calculateExplicitStateNumbers(FuncInfo, *PredBlock, CleanupState);
+  } else if (isa<TerminatePadInst>(FirstNonPHI)) {
+    report_fatal_error("Not yet implemented!");
+  } else {
+    llvm_unreachable("unexpected EH Pad!");
+  }
+}
+
 void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn,
                                          WinEHFuncInfo &FuncInfo) {
   // Return if it's already been done.
-  if (!FuncInfo.LandingPadStateMap.empty())
+  if (!FuncInfo.EHPadStateMap.empty())
+    return;
+
+  bool IsExplicit = false;
+  for (const BasicBlock &BB : *ParentFn) {
+    if (!BB.isEHPad())
+      continue;
+    // Check if the EH Pad has no exceptional successors (i.e. it unwinds to
+    // caller).  Cleanups are a little bit of a special case because their
+    // control flow cannot be determined by looking at the pad but instead by
+    // the pad's users.
+    bool HasNoSuccessors = false;
+    const Instruction *FirstNonPHI = BB.getFirstNonPHI();
+    if (FirstNonPHI->mayThrow()) {
+      HasNoSuccessors = true;
+    } else if (auto *CPI = dyn_cast<CleanupPadInst>(FirstNonPHI)) {
+      HasNoSuccessors =
+          CPI->use_empty() ||
+          cast<CleanupReturnInst>(CPI->user_back())->unwindsToCaller();
+    }
+
+    if (!HasNoSuccessors)
+      continue;
+    calculateExplicitStateNumbers(FuncInfo, BB, -1);
+    IsExplicit = true;
+  }
+
+  if (IsExplicit)
     return;
 
   WinEHNumbering Num(FuncInfo);
   Num.findActionRootLPads(*ParentFn);
   // The VisitedHandlers list is used by both findActionRootLPads and
   // calculateStateNumbers, but both functions need to visit all handlers.
   Num.VisitedHandlers.clear();
   Num.calculateStateNumbers(*ParentFn);
for (BasicBlock &BB : F) {
     bool EHPadHasPHI = BB.isEHPad() && isa<PHINode>(BB.begin());
     assert(!EHPadHasPHI && "EH Pad still has a PHI!");
     if (EHPadHasPHI)
       report_fatal_error("EH Pad still has a PHI!");
   }
 
   BlockColors.clear();
   FuncletBlocks.clear();
+
   return true;
 }
 
 // TODO: Share loads when one use dominates another, or when a catchpad exit
 // dominates uses (needs dominators).
 AllocaInst *WinEHPrepare::insertPHILoads(PHINode *PN, Function &F) {
   BasicBlock *PHIBlock = PN->getParent();
   AllocaInst *SpillSlot = nullptr;

llvm/trunk/lib/Target/X86/X86TargetMachine.cpp

 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 
 static cl::opt<bool> EnableMachineCombinerPass("x86-machine-combiner",
                                cl::desc("Enable the machine combiner pass"),
                                cl::init(true), cl::Hidden);
 
+namespace llvm {
+void initializeWinEHStatePassPass(PassRegistry &);
+}
+
 extern "C" void LLVMInitializeX86Target() {
   // Register the target.
   RegisterTargetMachine<X86TargetMachine> X(TheX86_32Target);
   RegisterTargetMachine<X86TargetMachine> Y(TheX86_64Target);
+
+  PassRegistry &PR = *PassRegistry::getPassRegistry();
+  initializeWinEHStatePassPass(PR);
 }
 
 static std::unique_ptr<TargetLoweringObjectFile> createTLOF(const Triple &TT) {
   if (TT.isOSBinFormatMachO()) {
     if (TT.getArch() == Triple::x86_64)
       return make_unique<X86_64MachoTargetObjectFile>();
     return make_unique<TargetLoweringObjectFileMachO>();
   }

llvm/trunk/lib/Target/X86/X86WinEHState.cpp

 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/Local.h"
 
 using namespace llvm;
 using namespace llvm::PatternMatch;
 
 #define DEBUG_TYPE "winehstate"
 
+namespace llvm { void initializeWinEHStatePassPass(PassRegistry &); }
+
 namespace {
 class WinEHStatePass : public FunctionPass {
 public:
   static char ID; // Pass identification, replacement for typeid.
 
-  WinEHStatePass() : FunctionPass(ID) {}
+  WinEHStatePass() : FunctionPass(ID) {
+    initializeWinEHStatePassPass(*PassRegistry::getPassRegistry());
+  }
 
   bool runOnFunction(Function &Fn) override;
 
   bool doInitialization(Module &M) override;
 
   bool doFinalization(Module &M) override;
 
   void getAnalysisUsage(AnalysisUsage &AU) const override;
 
   const char *getPassName() const override {
     return "Windows 32-bit x86 EH state insertion";
   }
 
 private:
   void emitExceptionRegistrationRecord(Function *F);
 
   void linkExceptionRegistration(IRBuilder<> &Builder, Function *Handler);
   void unlinkExceptionRegistration(IRBuilder<> &Builder);
-  void addCXXStateStores(Function &F, MachineModuleInfo &MMI);
-  void addSEHStateStores(Function &F, MachineModuleInfo &MMI);
+  void addCXXStateStores(Function &F, WinEHFuncInfo &FuncInfo);
+  void addSEHStateStores(Function &F, WinEHFuncInfo &FuncInfo);
   void addCXXStateStoresToFunclet(Value *ParentRegNode, WinEHFuncInfo &FuncInfo,
                                   Function &F, int BaseState);
   void insertStateNumberStore(Value *ParentRegNode, Instruction *IP, int State);
 
   Value *emitEHLSDA(IRBuilder<> &Builder, Function *F);
 
   Function *generateLSDAInEAXThunk(Function *ParentFunc);
 
private:
   Value *Link = nullptr;
 };
 }
 
 FunctionPass *llvm::createX86WinEHStatePass() { return new WinEHStatePass(); }
 
 char WinEHStatePass::ID = 0;
 
+INITIALIZE_PASS(WinEHStatePass, "x86-winehstate",
+                "Insert stores for EH state numbers", false, false)
+
 bool WinEHStatePass::doInitialization(Module &M) {
   TheModule = &M;
   FrameEscape = Intrinsic::getDeclaration(TheModule, Intrinsic::localescape);
   FrameRecover = Intrinsic::getDeclaration(TheModule, Intrinsic::localrecover);
   FrameAddress = Intrinsic::getDeclaration(TheModule, Intrinsic::frameaddress);
   return false;
 }
 
bool WinEHStatePass::runOnFunction(Function &F) {
 
   // Disable frame pointer elimination in this function.
   // FIXME: Do the nested handlers need to keep the parent ebp in ebp, or can we
   // use an arbitrary register?
   F.addFnAttr("no-frame-pointer-elim", "true");
 
   emitExceptionRegistrationRecord(&F);
 
-  auto *MMIPtr = getAnalysisIfAvailable<MachineModuleInfo>();
-  assert(MMIPtr && "MachineModuleInfo should always be available");
-  MachineModuleInfo &MMI = *MMIPtr;
+  auto *MMI = getAnalysisIfAvailable<MachineModuleInfo>();
+  // If MMI is null, create our own WinEHFuncInfo.  This only happens in opt
+  // tests.
+  std::unique_ptr<WinEHFuncInfo> FuncInfoPtr;
+  if (!MMI)
+    FuncInfoPtr.reset(new WinEHFuncInfo());
+  WinEHFuncInfo &FuncInfo =
+      *(MMI ? &MMI->getWinEHFuncInfo(&F) : FuncInfoPtr.get());
+
   switch (Personality) {
   default: llvm_unreachable("unexpected personality function");
-  case EHPersonality::MSVC_CXX:    addCXXStateStores(F, MMI); break;
-  case EHPersonality::MSVC_X86SEH: addSEHStateStores(F, MMI); break;
+  case EHPersonality::MSVC_CXX:
+    addCXXStateStores(F, FuncInfo);
+    break;
+  case EHPersonality::MSVC_X86SEH:
+    addSEHStateStores(F, FuncInfo);
+    break;
   }
 
   // Reset per-function state.
   PersonalityFn = nullptr;
   Personality = EHPersonality::Unknown;
   return true;
 }
 
void WinEHStatePass::unlinkExceptionRegistration(IRBuilder<> &Builder) {
   // [fs:00] = Link->Next
   Value *Next =
       Builder.CreateLoad(Builder.CreateStructGEP(LinkTy, Link, 0));
   Constant *FSZero =
       Constant::getNullValue(LinkTy->getPointerTo()->getPointerTo(257));
   Builder.CreateStore(Next, FSZero);
 }
 
-void WinEHStatePass::addCXXStateStores(Function &F, MachineModuleInfo &MMI) {
-  WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(&F);
+void WinEHStatePass::addCXXStateStores(Function &F, WinEHFuncInfo &FuncInfo) {
   calculateWinCXXEHStateNumbers(&F, FuncInfo);
 
   // The base state for the parent is -1.
   addCXXStateStoresToFunclet(RegNode, FuncInfo, F, -1);
 
   // Set up RegNodeEscapeIndex
   int RegNodeEscapeIndex = escapeRegNode(F);
   FuncInfo.EHRegNodeEscapeIndex = RegNodeEscapeIndex;
for (Instruction &I : BB) {
       if (auto *CI = dyn_cast<CallInst>(&I)) {
         // Possibly throwing call instructions have no actions to take after
         // an unwind. Ensure they are in the -1 state.
         if (CI->doesNotThrow())
           continue;
         insertStateNumberStore(ParentRegNode, CI, BaseState);
       } else if (auto *II = dyn_cast<InvokeInst>(&I)) {
         // Look up the state number of the landingpad this unwinds to.
-        LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst();
+        Instruction *PadInst = II->getUnwindDest()->getFirstNonPHI();
         // FIXME: Why does this assertion fail?
-        //assert(FuncInfo.LandingPadStateMap.count(LPI) && "LP has no state!");
-        int State = FuncInfo.LandingPadStateMap[LPI];
+        //assert(FuncInfo.EHPadStateMap.count(PadInst) && "EH Pad has no state!");
+        int State = FuncInfo.EHPadStateMap[PadInst];
         insertStateNumberStore(ParentRegNode, II, State);
       }
     }
   }
 }
 
 /// Assign every distinct landingpad a unique state number for SEH. Unlike C++
 /// EH, we can use this very simple algorithm while C++ EH cannot because catch
 /// handlers aren't outlined and the runtime doesn't have to figure out which
 /// catch handler frame to unwind to.
 /// FIXME: __finally blocks are outlined, so this approach may break down there.
-void WinEHStatePass::addSEHStateStores(Function &F, MachineModuleInfo &MMI) {
-  WinEHFuncInfo &FuncInfo = MMI.getWinEHFuncInfo(&F);
-
+void WinEHStatePass::addSEHStateStores(Function &F, WinEHFuncInfo &FuncInfo) {
   // Remember and return the index that we used. We save it in WinEHFuncInfo so
   // that we can lower llvm.x86.seh.recoverfp later in filter functions without
   // too much trouble.
   int RegNodeEscapeIndex = escapeRegNode(F);
   FuncInfo.EHRegNodeEscapeIndex = RegNodeEscapeIndex;
 
   // Iterate all the instructions and emit state number stores.
   int CurState = 0;
   SmallPtrSet<BasicBlock *, 4> ExceptBlocks;
   for (BasicBlock &BB : F) {
     for (auto I = BB.begin(), E = BB.end(); I != E; ++I) {
       if (auto *CI = dyn_cast<CallInst>(I)) {
         auto *Intrin = dyn_cast<IntrinsicInst>(CI);
         if (Intrin) {
           // Calls that "don't throw" are considered to be able to throw asynch
           // exceptions, but intrinsics cannot.
           continue;
         }
         insertStateNumberStore(RegNode, CI, -1);
       } else if (auto *II = dyn_cast<InvokeInst>(I)) {
         // Look up the state number of the landingpad this unwinds to.
         LandingPadInst *LPI = II->getUnwindDest()->getLandingPadInst();
         auto InsertionPair =
-            FuncInfo.LandingPadStateMap.insert(std::make_pair(LPI, CurState));
+            FuncInfo.EHPadStateMap.insert(std::make_pair(LPI, CurState));
         auto Iter = InsertionPair.first;
         int &State = Iter->second;
         bool Inserted = InsertionPair.second;
         if (Inserted) {
           // Each action consumes a state number.
           auto *EHActions = cast<IntrinsicInst>(LPI->getNextNode());
           SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
           parseEHActions(EHActions, ActionList);

llvm/trunk/test/CodeGen/WinEH/wineh-statenumbering.ll

+; RUN: opt -mtriple=i686-pc-windows-msvc -S -x86-winehstate  < %s | FileCheck %s
+
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-pc-windows-msvc"
+
+%rtti.TypeDescriptor2 = type { i8**, i8*, [3 x i8] }
+%eh.CatchableType = type { i32, i8*, i32, i32, i32, i32, i8* }
+%eh.CatchableTypeArray.1 = type { i32, [1 x %eh.CatchableType*] }
+%eh.ThrowInfo = type { i32, i8*, i8*, i8* }
+
+$"\01??_R0H@8" = comdat any
+
+$"_CT??_R0H@84" = comdat any
+
+$_CTA1H = comdat any
+
+$_TI1H = comdat any
+
+@"\01??_7type_info@@6B@" = external constant i8*
+@"\01??_R0H@8" = linkonce_odr global %rtti.TypeDescriptor2 { i8** @"\01??_7type_info@@6B@", i8* null, [3 x i8] c".H\00" }, comdat
+@"_CT??_R0H@84" = linkonce_odr unnamed_addr constant %eh.CatchableType { i32 1, i8* bitcast (%rtti.TypeDescriptor2* @"\01??_R0H@8" to i8*), i32 0, i32 -1, i32 0, i32 4, i8* null }, section ".xdata", comdat
+@_CTA1H = linkonce_odr unnamed_addr constant %eh.CatchableTypeArray.1 { i32 1, [1 x %eh.CatchableType*] [%eh.CatchableType* @"_CT??_R0H@84"] }, section ".xdata", comdat
+@_TI1H = linkonce_odr unnamed_addr constant %eh.ThrowInfo { i32 0, i8* null, i8* null, i8* bitcast (%eh.CatchableTypeArray.1* @_CTA1H to i8*) }, section ".xdata", comdat
+
+define i32 @main() #0 personality i32 (...)* @__CxxFrameHandler3 {
+entry:
+  %tmp = alloca i32, align 4
+  ; CHECK: entry:
+  ; CHECK:   store i32 -1
+  ; CHECK:   call void @g(i32 3)
+  call void @g(i32 3)
+  store i32 0, i32* %tmp, align 4
+  %0 = bitcast i32* %tmp to i8*
+  ; CHECK:   store i32 0
+  ; CHECK:   invoke void @_CxxThrowException(
+  invoke void @_CxxThrowException(i8* %0, %eh.ThrowInfo* nonnull @_TI1H) #1
+          to label %unreachable.for.entry unwind label %catch.dispatch
+
+catch.dispatch:                                   ; preds = %entry
+  %1 = catchpad token [i8* null, i8* null] to label %catch unwind label %catchendblock
+
+catch:                                            ; preds = %catch.dispatch
+  ; CHECK: catch:
+  ; CHECK:   store i32 2
+  ; CHECK:   invoke void @_CxxThrowException(
+  invoke void @_CxxThrowException(i8* null, %eh.ThrowInfo* null) #1
+          to label %unreachable unwind label %catch.dispatch.1
+
+catch.dispatch.1:                                 ; preds = %catch
+  %2 = catchpad token [i8* null, i8* null] to label %catch.3 unwind label %catchendblock.2
+
+catch.3:                                          ; preds = %catch.dispatch.1
+  ; CHECK: catch.3:
+  ; CHECK:   store i32 3
+  ; CHECK:   invoke void @g(i32 1)
+  invoke void @g(i32 1)
+          to label %invoke.cont unwind label %catchendblock.2
+
+invoke.cont:                                      ; preds = %catch.3
+  catchret token %2 to label %try.cont
+
+try.cont:                                         ; preds = %invoke.cont
+  ; CHECK: try.cont:
+  ; CHECK:   store i32 1
+  ; CHECK:   invoke void @g(i32 2)
+  invoke void @g(i32 2)
+          to label %invoke.cont.4 unwind label %catchendblock
+
+invoke.cont.4:                                    ; preds = %try.cont
+  unreachable
+
+catchendblock.2:                                  ; preds = %catch.3, %catch.dispatch.1
+  catchendpad unwind label %catchendblock
+
+catchendblock:                                    ; preds = %catchendblock.2, %try.cont, %catch.dispatch
+  catchendpad unwind to caller
+
+unreachable:                                      ; preds = %catch
+  unreachable
+
+unreachable.for.entry:                            ; preds = %entry
+  unreachable
+}
+
+declare void @g(i32) #0
+
+declare x86_stdcallcc void @_CxxThrowException(i8*, %eh.ThrowInfo*)
+
+declare i32 @__CxxFrameHandler3(...)
+
+attributes #0 = { "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-realign-stack" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { noreturn }
+
+!llvm.ident = !{!0}
+
+!0 = !{!"clang version 3.8.0 (trunk 245153) (llvm/trunk 245238)"}