diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/WinEHPrepare.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/WinEHPrepare.cpp | 3506 |
1 files changed, 847 insertions, 2659 deletions
diff --git a/contrib/llvm/lib/CodeGen/WinEHPrepare.cpp b/contrib/llvm/lib/CodeGen/WinEHPrepare.cpp index 0d26ed3..52fb922 100644 --- a/contrib/llvm/lib/CodeGen/WinEHPrepare.cpp +++ b/contrib/llvm/lib/CodeGen/WinEHPrepare.cpp @@ -18,66 +18,40 @@ #include "llvm/CodeGen/Passes.h" #include "llvm/ADT/MapVector.h" -#include "llvm/ADT/STLExtras.h" -#include "llvm/ADT/SmallSet.h" -#include "llvm/ADT/SetVector.h" -#include "llvm/ADT/Triple.h" -#include "llvm/ADT/TinyPtrVector.h" -#include "llvm/Analysis/LibCallSemantics.h" -#include "llvm/Analysis/TargetLibraryInfo.h" +#include "llvm/Analysis/CFG.h" +#include "llvm/Analysis/EHPersonalities.h" +#include "llvm/CodeGen/MachineBasicBlock.h" #include "llvm/CodeGen/WinEHFuncInfo.h" -#include "llvm/IR/Dominators.h" -#include "llvm/IR/Function.h" -#include "llvm/IR/IRBuilder.h" -#include "llvm/IR/Instructions.h" -#include "llvm/IR/IntrinsicInst.h" -#include "llvm/IR/Module.h" -#include "llvm/IR/PatternMatch.h" +#include "llvm/MC/MCSymbol.h" #include "llvm/Pass.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 "llvm/Transforms/Utils/PromoteMemToReg.h" -#include <memory> +#include "llvm/Transforms/Utils/SSAUpdater.h" using namespace llvm; -using namespace llvm::PatternMatch; #define DEBUG_TYPE "winehprepare" -namespace { - -// 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<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap; - -// TinyPtrVector cannot hold nullptr, so we need our own sentinel that isn't -// quite null. -AllocaInst *getCatchObjectSentinel() { - return static_cast<AllocaInst *>(nullptr) + 1; -} - -typedef SmallSet<BasicBlock *, 4> VisitedBlockSet; +static cl::opt<bool> DisableDemotion( + "disable-demotion", cl::Hidden, + cl::desc( + "Clone multicolor basic blocks but do not demote cross funclet values"), + cl::init(false)); -class LandingPadActions; -class LandingPadMap; - -typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy; -typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy; +static cl::opt<bool> DisableCleanups( + "disable-cleanups", cl::Hidden, + cl::desc("Do not remove implausible terminators or other similar cleanups"), + cl::init(false)); +namespace { + class WinEHPrepare : public FunctionPass { public: static char ID; // Pass identification, replacement for typeid. - WinEHPrepare(const TargetMachine *TM = nullptr) - : FunctionPass(ID) { - if (TM) - TheTriple = TM->getTargetTriple(); - } + WinEHPrepare(const TargetMachine *TM = nullptr) : FunctionPass(ID) {} bool runOnFunction(Function &Fn) override; @@ -90,264 +64,27 @@ public: } private: - bool prepareExceptionHandlers(Function &F, - SmallVectorImpl<LandingPadInst *> &LPads); - void identifyEHBlocks(Function &F, SmallVectorImpl<LandingPadInst *> &LPads); - void promoteLandingPadValues(LandingPadInst *LPad); - void demoteValuesLiveAcrossHandlers(Function &F, - SmallVectorImpl<LandingPadInst *> &LPads); - void findSEHEHReturnPoints(Function &F, - SetVector<BasicBlock *> &EHReturnBlocks); - void findCXXEHReturnPoints(Function &F, - SetVector<BasicBlock *> &EHReturnBlocks); - void getPossibleReturnTargets(Function *ParentF, Function *HandlerF, - SetVector<BasicBlock*> &Targets); - void completeNestedLandingPad(Function *ParentFn, - LandingPadInst *OutlinedLPad, - const LandingPadInst *OriginalLPad, - FrameVarInfoMap &VarInfo); - Function *createHandlerFunc(Function *ParentFn, Type *RetTy, - const Twine &Name, Module *M, Value *&ParentFP); - bool outlineHandler(ActionHandler *Action, Function *SrcFn, - LandingPadInst *LPad, BasicBlock *StartBB, - FrameVarInfoMap &VarInfo); - void addStubInvokeToHandlerIfNeeded(Function *Handler); - - void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions); - CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB, - VisitedBlockSet &VisitedBlocks); - void findCleanupHandlers(LandingPadActions &Actions, BasicBlock *StartBB, - BasicBlock *EndBB); - - void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB); - - Triple TheTriple; + void insertPHIStores(PHINode *OriginalPHI, AllocaInst *SpillSlot); + void + insertPHIStore(BasicBlock *PredBlock, Value *PredVal, AllocaInst *SpillSlot, + SmallVectorImpl<std::pair<BasicBlock *, Value *>> &Worklist); + AllocaInst *insertPHILoads(PHINode *PN, Function &F); + void replaceUseWithLoad(Value *V, Use &U, AllocaInst *&SpillSlot, + DenseMap<BasicBlock *, Value *> &Loads, Function &F); + bool prepareExplicitEH(Function &F); + void colorFunclets(Function &F); + + void demotePHIsOnFunclets(Function &F); + void cloneCommonBlocks(Function &F); + void removeImplausibleInstructions(Function &F); + void cleanupPreparedFunclets(Function &F); + void verifyPreparedFunclets(Function &F); // All fields are reset by runOnFunction. - DominatorTree *DT = nullptr; - const TargetLibraryInfo *LibInfo = nullptr; EHPersonality Personality = EHPersonality::Unknown; - CatchHandlerMapTy CatchHandlerMap; - CleanupHandlerMapTy CleanupHandlerMap; - DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps; - SmallPtrSet<BasicBlock *, 4> NormalBlocks; - SmallPtrSet<BasicBlock *, 4> EHBlocks; - SetVector<BasicBlock *> EHReturnBlocks; - - // This maps landing pad instructions found in outlined handlers to - // the landing pad instruction in the parent function from which they - // were cloned. The cloned/nested landing pad is used as the key - // because the landing pad may be cloned into multiple handlers. - // This map will be used to add the llvm.eh.actions call to the nested - // landing pads after all handlers have been outlined. - DenseMap<LandingPadInst *, const LandingPadInst *> NestedLPtoOriginalLP; - - // This maps blocks in the parent function which are destinations of - // catch handlers to cloned blocks in (other) outlined handlers. This - // handles the case where a nested landing pads has a catch handler that - // returns to a handler function rather than the parent function. - // The original block is used as the key here because there should only - // ever be one handler function from which the cloned block is not pruned. - // The original block will be pruned from the parent function after all - // handlers have been outlined. This map will be used to adjust the - // return instructions of handlers which return to the block that was - // outlined into a handler. This is done after all handlers have been - // outlined but before the outlined code is pruned from the parent function. - DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks; - - // Map from outlined handler to call to parent local address. Only used for - // 32-bit EH. - DenseMap<Function *, Value *> HandlerToParentFP; - - AllocaInst *SEHExceptionCodeSlot = nullptr; -}; - -class WinEHFrameVariableMaterializer : public ValueMaterializer { -public: - WinEHFrameVariableMaterializer(Function *OutlinedFn, Value *ParentFP, - FrameVarInfoMap &FrameVarInfo); - ~WinEHFrameVariableMaterializer() override {} - - Value *materializeValueFor(Value *V) override; - - void escapeCatchObject(Value *V); - -private: - FrameVarInfoMap &FrameVarInfo; - IRBuilder<> Builder; -}; - -class LandingPadMap { -public: - LandingPadMap() : OriginLPad(nullptr) {} - void mapLandingPad(const LandingPadInst *LPad); - - bool isInitialized() { return OriginLPad != nullptr; } - - bool isOriginLandingPadBlock(const BasicBlock *BB) const; - bool isLandingPadSpecificInst(const Instruction *Inst) const; - - void remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue, - Value *SelectorValue) const; - -private: - 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; -}; - -class WinEHCloningDirectorBase : public CloningDirector { -public: - WinEHCloningDirectorBase(Function *HandlerFn, Value *ParentFP, - FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap) - : Materializer(HandlerFn, ParentFP, VarInfo), - SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())), - Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())), - LPadMap(LPadMap), ParentFP(ParentFP) {} - - 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 handleIndirectBr(ValueToValueMapTy &VMap, - const IndirectBrInst *IBr, - 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; - virtual CloningAction handleCompare(ValueToValueMapTy &VMap, - const CmpInst *Compare, - BasicBlock *NewBB) = 0; - virtual CloningAction handleLandingPad(ValueToValueMapTy &VMap, - const LandingPadInst *LPad, - BasicBlock *NewBB) = 0; - - ValueMaterializer *getValueMaterializer() override { return &Materializer; } - -protected: - WinEHFrameVariableMaterializer Materializer; - Type *SelectorIDType; - Type *Int8PtrType; - LandingPadMap &LPadMap; - - /// The value representing the parent frame pointer. - Value *ParentFP; -}; - -class WinEHCatchDirector : public WinEHCloningDirectorBase { -public: - WinEHCatchDirector( - Function *CatchFn, Value *ParentFP, Value *Selector, - FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap, - DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads, - DominatorTree *DT, SmallPtrSetImpl<BasicBlock *> &EHBlocks) - : WinEHCloningDirectorBase(CatchFn, ParentFP, VarInfo, LPadMap), - CurrentSelector(Selector->stripPointerCasts()), - ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads), - DT(DT), EHBlocks(EHBlocks) {} - - 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 handleIndirectBr(ValueToValueMapTy &VMap, - const IndirectBrInst *IBr, - BasicBlock *NewBB) override; - CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke, - BasicBlock *NewBB) override; - CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, - BasicBlock *NewBB) override; - CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare, - BasicBlock *NewBB) override; - CloningAction handleLandingPad(ValueToValueMapTy &VMap, - const LandingPadInst *LPad, - BasicBlock *NewBB) override; - - Value *getExceptionVar() { return ExceptionObjectVar; } - TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; } - -private: - Value *CurrentSelector; - - Value *ExceptionObjectVar; - TinyPtrVector<BasicBlock *> ReturnTargets; - // This will be a reference to the field of the same name in the WinEHPrepare - // object which instantiates this WinEHCatchDirector object. - DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPtoOriginalLP; - DominatorTree *DT; - SmallPtrSetImpl<BasicBlock *> &EHBlocks; -}; - -class WinEHCleanupDirector : public WinEHCloningDirectorBase { -public: - WinEHCleanupDirector(Function *CleanupFn, Value *ParentFP, - FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap) - : WinEHCloningDirectorBase(CleanupFn, ParentFP, 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 handleIndirectBr(ValueToValueMapTy &VMap, - const IndirectBrInst *IBr, - BasicBlock *NewBB) override; - CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke, - BasicBlock *NewBB) override; - CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, - BasicBlock *NewBB) override; - CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare, - BasicBlock *NewBB) override; - CloningAction handleLandingPad(ValueToValueMapTy &VMap, - const LandingPadInst *LPad, - BasicBlock *NewBB) override; -}; - -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 *> &actions() { return Actions; } - 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; + DenseMap<BasicBlock *, ColorVector> BlockColors; + MapVector<BasicBlock *, std::vector<BasicBlock *>> FuncletBlocks; }; } // end anonymous namespace @@ -361,2536 +98,987 @@ FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) { } bool WinEHPrepare::runOnFunction(Function &Fn) { - // No need to prepare outlined handlers. - if (Fn.hasFnAttribute("wineh-parent")) - return false; - - SmallVector<LandingPadInst *, 4> LPads; - SmallVector<ResumeInst *, 4> Resumes; - for (BasicBlock &BB : Fn) { - if (auto *LP = BB.getLandingPadInst()) - LPads.push_back(LP); - if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator())) - Resumes.push_back(Resume); - } - - // No need to prepare functions that lack landing pads. - if (LPads.empty()) + if (!Fn.hasPersonalityFn()) return false; // Classify the personality to see what kind of preparation we need. Personality = classifyEHPersonality(Fn.getPersonalityFn()); - // Do nothing if this is not an MSVC personality. - if (!isMSVCEHPersonality(Personality)) + // Do nothing if this is not a funclet-based personality. + if (!isFuncletEHPersonality(Personality)) return false; - DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree(); - LibInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(); - - // If there were any landing pads, prepareExceptionHandlers will make changes. - prepareExceptionHandlers(Fn, LPads); - return true; + return prepareExplicitEH(Fn); } bool WinEHPrepare::doFinalization(Module &M) { return false; } -void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequired<DominatorTreeWrapperPass>(); - AU.addRequired<TargetLibraryInfoWrapperPass>(); -} - -static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler, - Constant *&Selector, BasicBlock *&NextBB); - -// Finds blocks reachable from the starting set Worklist. Does not follow unwind -// edges or blocks listed in StopPoints. -static void findReachableBlocks(SmallPtrSetImpl<BasicBlock *> &ReachableBBs, - SetVector<BasicBlock *> &Worklist, - const SetVector<BasicBlock *> *StopPoints) { - while (!Worklist.empty()) { - BasicBlock *BB = Worklist.pop_back_val(); +void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {} - // Don't cross blocks that we should stop at. - if (StopPoints && StopPoints->count(BB)) - continue; - - if (!ReachableBBs.insert(BB).second) - continue; // Already visited. - - // Don't follow unwind edges of invokes. - if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) { - Worklist.insert(II->getNormalDest()); - continue; - } - - // Otherwise, follow all successors. - Worklist.insert(succ_begin(BB), succ_end(BB)); - } -} - -// Attempt to find an instruction where a block can be split before -// a call to llvm.eh.begincatch and its operands. If the block -// begins with the begincatch call or one of its adjacent operands -// the block will not be split. -static Instruction *findBeginCatchSplitPoint(BasicBlock *BB, - IntrinsicInst *II) { - // If the begincatch call is already the first instruction in the block, - // don't split. - Instruction *FirstNonPHI = BB->getFirstNonPHI(); - if (II == FirstNonPHI) - return nullptr; - - // If either operand is in the same basic block as the instruction and - // isn't used by another instruction before the begincatch call, include it - // in the split block. - auto *Op0 = dyn_cast<Instruction>(II->getOperand(0)); - auto *Op1 = dyn_cast<Instruction>(II->getOperand(1)); - - Instruction *I = II->getPrevNode(); - Instruction *LastI = II; - - while (I == Op0 || I == Op1) { - // If the block begins with one of the operands and there are no other - // instructions between the operand and the begincatch call, don't split. - if (I == FirstNonPHI) - return nullptr; - - LastI = I; - I = I->getPrevNode(); - } - - // If there is at least one instruction in the block before the begincatch - // call and its operands, split the block at either the begincatch or - // its operand. - return LastI; +static int addUnwindMapEntry(WinEHFuncInfo &FuncInfo, int ToState, + const BasicBlock *BB) { + CxxUnwindMapEntry UME; + UME.ToState = ToState; + UME.Cleanup = BB; + FuncInfo.CxxUnwindMap.push_back(UME); + return FuncInfo.getLastStateNumber(); } -/// Find all points where exceptional control rejoins normal control flow via -/// llvm.eh.endcatch. Add them to the normal bb reachability worklist. -void WinEHPrepare::findCXXEHReturnPoints( - Function &F, SetVector<BasicBlock *> &EHReturnBlocks) { - for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) { - BasicBlock *BB = BBI; - for (Instruction &I : *BB) { - if (match(&I, m_Intrinsic<Intrinsic::eh_begincatch>())) { - Instruction *SplitPt = - findBeginCatchSplitPoint(BB, cast<IntrinsicInst>(&I)); - if (SplitPt) { - // Split the block before the llvm.eh.begincatch call to allow - // cleanup and catch code to be distinguished later. - // Do not update BBI because we still need to process the - // portion of the block that we are splitting off. - SplitBlock(BB, SplitPt, DT); - break; - } - } - if (match(&I, m_Intrinsic<Intrinsic::eh_endcatch>())) { - // Split the block after the call to llvm.eh.endcatch if there is - // anything other than an unconditional branch, or if the successor - // starts with a phi. - auto *Br = dyn_cast<BranchInst>(I.getNextNode()); - if (!Br || !Br->isUnconditional() || - isa<PHINode>(Br->getSuccessor(0)->begin())) { - DEBUG(dbgs() << "splitting block " << BB->getName() - << " with llvm.eh.endcatch\n"); - BBI = SplitBlock(BB, I.getNextNode(), DT); - } - // The next BB is normal control flow. - EHReturnBlocks.insert(BB->getTerminator()->getSuccessor(0)); - break; - } - } +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.TypeDescriptor = nullptr; + else + HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts()); + HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue(); + HT.Handler = CPI->getParent(); + if (isa<ConstantPointerNull>(CPI->getArgOperand(2))) + HT.CatchObj.Alloca = nullptr; + else + HT.CatchObj.Alloca = cast<AllocaInst>(CPI->getArgOperand(2)); + TBME.HandlerArray.push_back(HT); } + FuncInfo.TryBlockMap.push_back(TBME); } -static bool isCatchAllLandingPad(const BasicBlock *BB) { - const LandingPadInst *LP = BB->getLandingPadInst(); - if (!LP) - return false; - unsigned N = LP->getNumClauses(); - return (N > 0 && LP->isCatch(N - 1) && - isa<ConstantPointerNull>(LP->getClause(N - 1))); +static BasicBlock *getCleanupRetUnwindDest(const CleanupPadInst *CleanupPad) { + for (const User *U : CleanupPad->users()) + if (const auto *CRI = dyn_cast<CleanupReturnInst>(U)) + return CRI->getUnwindDest(); + return nullptr; } -/// Find all points where exceptions control rejoins normal control flow via -/// selector dispatch. -void WinEHPrepare::findSEHEHReturnPoints( - Function &F, SetVector<BasicBlock *> &EHReturnBlocks) { - for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) { - BasicBlock *BB = BBI; - // If the landingpad is a catch-all, treat the whole lpad as if it is - // reachable from normal control flow. - // FIXME: This is imprecise. We need a better way of identifying where a - // catch-all starts and cleanups stop. As far as LLVM is concerned, there - // is no difference. - if (isCatchAllLandingPad(BB)) { - EHReturnBlocks.insert(BB); +static void calculateStateNumbersForInvokes(const Function *Fn, + WinEHFuncInfo &FuncInfo) { + auto *F = const_cast<Function *>(Fn); + DenseMap<BasicBlock *, ColorVector> BlockColors = colorEHFunclets(*F); + for (BasicBlock &BB : *F) { + auto *II = dyn_cast<InvokeInst>(BB.getTerminator()); + if (!II) continue; - } - - BasicBlock *CatchHandler; - BasicBlock *NextBB; - Constant *Selector; - if (isSelectorDispatch(BB, CatchHandler, Selector, NextBB)) { - // Split the edge if there are multiple predecessors. This creates a place - // where we can insert EH recovery code. - if (!CatchHandler->getSinglePredecessor()) { - DEBUG(dbgs() << "splitting EH return edge from " << BB->getName() - << " to " << CatchHandler->getName() << '\n'); - BBI = CatchHandler = SplitCriticalEdge( - BB, std::find(succ_begin(BB), succ_end(BB), CatchHandler)); - } - EHReturnBlocks.insert(CatchHandler); - } - } -} -void WinEHPrepare::identifyEHBlocks(Function &F, - SmallVectorImpl<LandingPadInst *> &LPads) { - DEBUG(dbgs() << "Demoting values live across exception handlers in function " - << F.getName() << '\n'); - - // Build a set of all non-exceptional blocks and exceptional blocks. - // - Non-exceptional blocks are blocks reachable from the entry block while - // not following invoke unwind edges. - // - Exceptional blocks are blocks reachable from landingpads. Analysis does - // not follow llvm.eh.endcatch blocks, which mark a transition from - // exceptional to normal control. - - if (Personality == EHPersonality::MSVC_CXX) - findCXXEHReturnPoints(F, EHReturnBlocks); - else - findSEHEHReturnPoints(F, EHReturnBlocks); - - DEBUG({ - dbgs() << "identified the following blocks as EH return points:\n"; - for (BasicBlock *BB : EHReturnBlocks) - dbgs() << " " << BB->getName() << '\n'; - }); - -// Join points should not have phis at this point, unless they are a -// landingpad, in which case we will demote their phis later. -#ifndef NDEBUG - for (BasicBlock *BB : EHReturnBlocks) - assert((BB->isLandingPad() || !isa<PHINode>(BB->begin())) && - "non-lpad EH return block has phi"); -#endif - - // Normal blocks are the blocks reachable from the entry block and all EH - // return points. - SetVector<BasicBlock *> Worklist; - Worklist = EHReturnBlocks; - Worklist.insert(&F.getEntryBlock()); - findReachableBlocks(NormalBlocks, Worklist, nullptr); - DEBUG({ - dbgs() << "marked the following blocks as normal:\n"; - for (BasicBlock *BB : NormalBlocks) - dbgs() << " " << BB->getName() << '\n'; - }); - - // Exceptional blocks are the blocks reachable from landingpads that don't - // cross EH return points. - Worklist.clear(); - for (auto *LPI : LPads) - Worklist.insert(LPI->getParent()); - findReachableBlocks(EHBlocks, Worklist, &EHReturnBlocks); - DEBUG({ - dbgs() << "marked the following blocks as exceptional:\n"; - for (BasicBlock *BB : EHBlocks) - dbgs() << " " << BB->getName() << '\n'; - }); - -} - -/// Ensure that all values live into and out of exception handlers are stored -/// in memory. -/// FIXME: This falls down when values are defined in one handler and live into -/// another handler. For example, a cleanup defines a value used only by a -/// catch handler. -void WinEHPrepare::demoteValuesLiveAcrossHandlers( - Function &F, SmallVectorImpl<LandingPadInst *> &LPads) { - DEBUG(dbgs() << "Demoting values live across exception handlers in function " - << F.getName() << '\n'); - - // identifyEHBlocks() should have been called before this function. - assert(!NormalBlocks.empty()); - - // Try to avoid demoting EH pointer and selector values. They get in the way - // of our pattern matching. - SmallPtrSet<Instruction *, 10> EHVals; - for (BasicBlock &BB : F) { - LandingPadInst *LP = BB.getLandingPadInst(); - if (!LP) - continue; - EHVals.insert(LP); - for (User *U : LP->users()) { - auto *EI = dyn_cast<ExtractValueInst>(U); - if (!EI) - continue; - EHVals.insert(EI); - for (User *U2 : EI->users()) { - if (auto *PN = dyn_cast<PHINode>(U2)) - EHVals.insert(PN); - } + auto &BBColors = BlockColors[&BB]; + assert(BBColors.size() == 1 && "multi-color BB not removed by preparation"); + BasicBlock *FuncletEntryBB = BBColors.front(); + + BasicBlock *FuncletUnwindDest; + auto *FuncletPad = + dyn_cast<FuncletPadInst>(FuncletEntryBB->getFirstNonPHI()); + assert(FuncletPad || FuncletEntryBB == &Fn->getEntryBlock()); + if (!FuncletPad) + FuncletUnwindDest = nullptr; + else if (auto *CatchPad = dyn_cast<CatchPadInst>(FuncletPad)) + FuncletUnwindDest = CatchPad->getCatchSwitch()->getUnwindDest(); + else if (auto *CleanupPad = dyn_cast<CleanupPadInst>(FuncletPad)) + FuncletUnwindDest = getCleanupRetUnwindDest(CleanupPad); + else + llvm_unreachable("unexpected funclet pad!"); + + BasicBlock *InvokeUnwindDest = II->getUnwindDest(); + int BaseState = -1; + if (FuncletUnwindDest == InvokeUnwindDest) { + auto BaseStateI = FuncInfo.FuncletBaseStateMap.find(FuncletPad); + if (BaseStateI != FuncInfo.FuncletBaseStateMap.end()) + BaseState = BaseStateI->second; } - } - SetVector<Argument *> ArgsToDemote; - SetVector<Instruction *> InstrsToDemote; - for (BasicBlock &BB : F) { - bool IsNormalBB = NormalBlocks.count(&BB); - bool IsEHBB = EHBlocks.count(&BB); - if (!IsNormalBB && !IsEHBB) - continue; // Blocks that are neither normal nor EH are unreachable. - for (Instruction &I : BB) { - for (Value *Op : I.operands()) { - // Don't demote static allocas, constants, and labels. - if (isa<Constant>(Op) || isa<BasicBlock>(Op) || isa<InlineAsm>(Op)) - continue; - auto *AI = dyn_cast<AllocaInst>(Op); - if (AI && AI->isStaticAlloca()) - continue; - - if (auto *Arg = dyn_cast<Argument>(Op)) { - if (IsEHBB) { - DEBUG(dbgs() << "Demoting argument " << *Arg - << " used by EH instr: " << I << "\n"); - ArgsToDemote.insert(Arg); - } - continue; - } - - // Don't demote EH values. - auto *OpI = cast<Instruction>(Op); - if (EHVals.count(OpI)) - continue; - - BasicBlock *OpBB = OpI->getParent(); - // If a value is produced and consumed in the same BB, we don't need to - // demote it. - if (OpBB == &BB) - continue; - bool IsOpNormalBB = NormalBlocks.count(OpBB); - bool IsOpEHBB = EHBlocks.count(OpBB); - if (IsNormalBB != IsOpNormalBB || IsEHBB != IsOpEHBB) { - DEBUG({ - dbgs() << "Demoting instruction live in-out from EH:\n"; - dbgs() << "Instr: " << *OpI << '\n'; - dbgs() << "User: " << I << '\n'; - }); - InstrsToDemote.insert(OpI); - } - } - } - } - - // Demote values live into and out of handlers. - // FIXME: This demotion is inefficient. We should insert spills at the point - // of definition, insert one reload in each handler that uses the value, and - // insert reloads in the BB used to rejoin normal control flow. - Instruction *AllocaInsertPt = F.getEntryBlock().getFirstInsertionPt(); - for (Instruction *I : InstrsToDemote) - DemoteRegToStack(*I, false, AllocaInsertPt); - - // Demote arguments separately, and only for uses in EH blocks. - for (Argument *Arg : ArgsToDemote) { - auto *Slot = new AllocaInst(Arg->getType(), nullptr, - Arg->getName() + ".reg2mem", AllocaInsertPt); - SmallVector<User *, 4> Users(Arg->user_begin(), Arg->user_end()); - for (User *U : Users) { - auto *I = dyn_cast<Instruction>(U); - if (I && EHBlocks.count(I->getParent())) { - auto *Reload = new LoadInst(Slot, Arg->getName() + ".reload", false, I); - U->replaceUsesOfWith(Arg, Reload); - } + if (BaseState != -1) { + FuncInfo.InvokeStateMap[II] = BaseState; + } else { + Instruction *PadInst = InvokeUnwindDest->getFirstNonPHI(); + assert(FuncInfo.EHPadStateMap.count(PadInst) && "EH Pad has no state!"); + FuncInfo.InvokeStateMap[II] = FuncInfo.EHPadStateMap[PadInst]; } - new StoreInst(Arg, Slot, AllocaInsertPt); - } - - // Demote landingpad phis, as the landingpad will be removed from the machine - // CFG. - for (LandingPadInst *LPI : LPads) { - BasicBlock *BB = LPI->getParent(); - while (auto *Phi = dyn_cast<PHINode>(BB->begin())) - DemotePHIToStack(Phi, AllocaInsertPt); } - - DEBUG(dbgs() << "Demoted " << InstrsToDemote.size() << " instructions and " - << ArgsToDemote.size() << " arguments for WinEHPrepare\n\n"); } -bool WinEHPrepare::prepareExceptionHandlers( - Function &F, SmallVectorImpl<LandingPadInst *> &LPads) { - // Don't run on functions that are already prepared. - for (LandingPadInst *LPad : LPads) { - BasicBlock *LPadBB = LPad->getParent(); - for (Instruction &Inst : *LPadBB) - if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>())) - return false; - } - - identifyEHBlocks(F, LPads); - demoteValuesLiveAcrossHandlers(F, 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; - - 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); - - if (isAsynchronousEHPersonality(Personality)) { - // FIXME: Switch the ehptr type to i32 and then switch this. - SEHExceptionCodeSlot = - new AllocaInst(Int8PtrType, nullptr, "seh_exception_code", - F.getEntryBlock().getFirstInsertionPt()); +// 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, + Value *ParentPad) { + const TerminatorInst *TI = BB->getTerminator(); + if (isa<InvokeInst>(TI)) + return nullptr; + if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(TI)) { + if (CatchSwitch->getParentPad() != ParentPad) + return nullptr; + return BB; } + assert(!TI->isEHPad() && "unexpected EHPad!"); + auto *CleanupPad = cast<CleanupReturnInst>(TI)->getCleanupPad(); + if (CleanupPad->getParentPad() != ParentPad) + return nullptr; + return CleanupPad->getParent(); +} - // In order to handle the case where one outlined catch handler returns - // to a block within another outlined catch handler that would otherwise - // be unreachable, we need to outline the nested landing pad before we - // outline the landing pad which encloses it. - if (!isAsynchronousEHPersonality(Personality)) - std::sort(LPads.begin(), LPads.end(), - [this](LandingPadInst *const &L, LandingPadInst *const &R) { - return DT->properlyDominates(R->getParent(), L->getParent()); - }); - - // This container stores the llvm.eh.recover and IndirectBr instructions - // that make up the body of each landing pad after it has been outlined. - // We need to defer the population of the target list for the indirectbr - // until all landing pads have been outlined so that we can handle the - // case of blocks in the target that are reached only from nested - // landing pads. - SmallVector<std::pair<CallInst*, IndirectBrInst *>, 4> LPadImpls; - - 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) { - if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>())) { - LPadHasActionList = true; - break; - } - } - - // If we've already outlined the handlers for this landingpad, - // there's nothing more to do here. - if (LPadHasActionList) - continue; - - // If either of the values in the aggregate returned by the landing pad is - // extracted and stored to memory, promote the stored value to a register. - promoteLandingPadValues(LPad); - - LandingPadActions Actions; - mapLandingPadBlocks(LPad, Actions); - - HandlersOutlined |= !Actions.actions().empty(); - 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); - continue; - } - } - - outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo); - } - - // Split the block after the landingpad instruction so that it is just a - // call to llvm.eh.actions followed by indirectbr. - assert(!isa<PHINode>(LPadBB->begin()) && "lpad phi not removed"); - SplitBlock(LPadBB, LPad->getNextNode(), DT); - // Erase the branch inserted by the split so we can insert indirectbr. - LPadBB->getTerminator()->eraseFromParent(); - - // Replace all extracted values with undef and ultimately replace the - // landingpad with undef. - SmallVector<Instruction *, 4> SEHCodeUses; - SmallVector<Instruction *, 4> EHUndefs; - for (User *U : LPad->users()) { - auto *E = dyn_cast<ExtractValueInst>(U); - if (!E) - continue; - assert(E->getNumIndices() == 1 && - "Unexpected operation: extracting both landing pad values"); - unsigned Idx = *E->idx_begin(); - assert((Idx == 0 || Idx == 1) && "unexpected index"); - if (Idx == 0 && isAsynchronousEHPersonality(Personality)) - SEHCodeUses.push_back(E); - else - EHUndefs.push_back(E); - } - for (Instruction *E : EHUndefs) { - E->replaceAllUsesWith(UndefValue::get(E->getType())); - E->eraseFromParent(); - } - LPad->replaceAllUsesWith(UndefValue::get(LPad->getType())); - - // Rewrite uses of the exception pointer to loads of an alloca. - while (!SEHCodeUses.empty()) { - Instruction *E = SEHCodeUses.pop_back_val(); - SmallVector<Use *, 4> Uses; - for (Use &U : E->uses()) - Uses.push_back(&U); - for (Use *U : Uses) { - auto *I = cast<Instruction>(U->getUser()); - if (isa<ResumeInst>(I)) - continue; - if (auto *Phi = dyn_cast<PHINode>(I)) - SEHCodeUses.push_back(Phi); - else - U->set(new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I)); - } - E->replaceAllUsesWith(UndefValue::get(E->getType())); - E->eraseFromParent(); - } - - // 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()); - // Find the frame escape index of the exception object alloca in the - // parent. - int FrameEscapeIdx = -1; - Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar()); - if (EHObj && !isa<ConstantPointerNull>(EHObj)) { - auto I = FrameVarInfo.find(EHObj); - assert(I != FrameVarInfo.end() && - "failed to map llvm.eh.begincatch var"); - FrameEscapeIdx = std::distance(FrameVarInfo.begin(), I); - } - ActionArgs.push_back(ConstantInt::get(Int32Type, FrameEscapeIdx)); - } else { - ActionArgs.push_back(ConstantInt::get(Int32Type, 0)); - } - ActionArgs.push_back(Action->getHandlerBlockOrFunc()); - } - CallInst *Recover = - CallInst::Create(ActionIntrin, ActionArgs, "recover", LPadBB); - - SetVector<BasicBlock *> ReturnTargets; - for (ActionHandler *Action : Actions) { - if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) { - const auto &CatchTargets = CatchAction->getReturnTargets(); - ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end()); - } - } - IndirectBrInst *Branch = - IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB); - for (BasicBlock *Target : ReturnTargets) - Branch->addDestination(Target); - - if (!isAsynchronousEHPersonality(Personality)) { - // C++ EH must repopulate the targets later to handle the case of - // targets that are reached indirectly through nested landing pads. - LPadImpls.push_back(std::make_pair(Recover, Branch)); - } - - } // End for each landingpad +static void calculateCXXStateNumbers(WinEHFuncInfo &FuncInfo, + const Instruction *FirstNonPHI, + int ParentState) { + const BasicBlock *BB = FirstNonPHI->getParent(); + assert(BB->isEHPad() && "not a funclet!"); - // If nothing got outlined, there is no more processing to be done. - if (!HandlersOutlined) - return false; + if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(FirstNonPHI)) { + assert(FuncInfo.EHPadStateMap.count(CatchSwitch) == 0 && + "shouldn't revist catch funclets!"); - // Replace any nested landing pad stubs with the correct action handler. - // This must be done before we remove unreachable blocks because it - // cleans up references to outlined blocks that will be deleted. - for (auto &LPadPair : NestedLPtoOriginalLP) - completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo); - NestedLPtoOriginalLP.clear(); - - // Update the indirectbr instructions' target lists if necessary. - SetVector<BasicBlock*> CheckedTargets; - SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList; - for (auto &LPadImplPair : LPadImpls) { - IntrinsicInst *Recover = cast<IntrinsicInst>(LPadImplPair.first); - IndirectBrInst *Branch = LPadImplPair.second; - - // Get a list of handlers called by - parseEHActions(Recover, ActionList); - - // Add an indirect branch listing possible successors of the catch handlers. - SetVector<BasicBlock *> ReturnTargets; - for (const auto &Action : ActionList) { - if (auto *CA = dyn_cast<CatchHandler>(Action.get())) { - Function *Handler = cast<Function>(CA->getHandlerBlockOrFunc()); - getPossibleReturnTargets(&F, Handler, ReturnTargets); - } - } - ActionList.clear(); - // Clear any targets we already knew about. - for (unsigned int I = 0, E = Branch->getNumDestinations(); I < E; ++I) { - BasicBlock *KnownTarget = Branch->getDestination(I); - if (ReturnTargets.count(KnownTarget)) - ReturnTargets.remove(KnownTarget); + SmallVector<const CatchPadInst *, 2> Handlers; + for (const BasicBlock *CatchPadBB : CatchSwitch->handlers()) { + auto *CatchPad = cast<CatchPadInst>(CatchPadBB->getFirstNonPHI()); + Handlers.push_back(CatchPad); } - for (BasicBlock *Target : ReturnTargets) { - Branch->addDestination(Target); - // The target may be a block that we excepted to get pruned. - // If it is, it may contain a call to llvm.eh.endcatch. - if (CheckedTargets.insert(Target)) { - // Earlier preparations guarantee that all calls to llvm.eh.endcatch - // will be followed by an unconditional branch. - auto *Br = dyn_cast<BranchInst>(Target->getTerminator()); - if (Br && Br->isUnconditional() && - Br != Target->getFirstNonPHIOrDbgOrLifetime()) { - Instruction *Prev = Br->getPrevNode(); - if (match(cast<Value>(Prev), m_Intrinsic<Intrinsic::eh_endcatch>())) - Prev->eraseFromParent(); - } + int TryLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr); + FuncInfo.EHPadStateMap[CatchSwitch] = TryLow; + for (const BasicBlock *PredBlock : predecessors(BB)) + if ((PredBlock = getEHPadFromPredecessor(PredBlock, + CatchSwitch->getParentPad()))) + calculateCXXStateNumbers(FuncInfo, PredBlock->getFirstNonPHI(), + TryLow); + int CatchLow = addUnwindMapEntry(FuncInfo, ParentState, nullptr); + + // catchpads are separate funclets in C++ EH due to the way rethrow works. + int TryHigh = CatchLow - 1; + for (const auto *CatchPad : Handlers) { + FuncInfo.FuncletBaseStateMap[CatchPad] = CatchLow; + for (const User *U : CatchPad->users()) { + const auto *UserI = cast<Instruction>(U); + if (auto *InnerCatchSwitch = dyn_cast<CatchSwitchInst>(UserI)) + if (InnerCatchSwitch->getUnwindDest() == CatchSwitch->getUnwindDest()) + calculateCXXStateNumbers(FuncInfo, UserI, CatchLow); + if (auto *InnerCleanupPad = dyn_cast<CleanupPadInst>(UserI)) + if (getCleanupRetUnwindDest(InnerCleanupPad) == + CatchSwitch->getUnwindDest()) + calculateCXXStateNumbers(FuncInfo, UserI, CatchLow); } } - } - LPadImpls.clear(); - - F.addFnAttr("wineh-parent", F.getName()); - - // Delete any blocks that were only used by handlers that were outlined above. - removeUnreachableBlocks(F); + int CatchHigh = FuncInfo.getLastStateNumber(); + addTryBlockMapEntry(FuncInfo, TryLow, TryHigh, CatchHigh, Handlers); + DEBUG(dbgs() << "TryLow[" << BB->getName() << "]: " << TryLow << '\n'); + DEBUG(dbgs() << "TryHigh[" << BB->getName() << "]: " << TryHigh << '\n'); + DEBUG(dbgs() << "CatchHigh[" << BB->getName() << "]: " << CatchHigh + << '\n'); + } else { + auto *CleanupPad = cast<CleanupPadInst>(FirstNonPHI); - BasicBlock *Entry = &F.getEntryBlock(); - IRBuilder<> Builder(F.getParent()->getContext()); - Builder.SetInsertPoint(Entry->getFirstInsertionPt()); - - Function *FrameEscapeFn = - Intrinsic::getDeclaration(M, Intrinsic::localescape); - Function *RecoverFrameFn = - Intrinsic::getDeclaration(M, Intrinsic::localrecover); - SmallVector<Value *, 8> AllocasToEscape; - - // Scan the entry block for an existing call to llvm.localescape. We need to - // keep escaping those objects. - for (Instruction &I : F.front()) { - auto *II = dyn_cast<IntrinsicInst>(&I); - if (II && II->getIntrinsicID() == Intrinsic::localescape) { - auto Args = II->arg_operands(); - AllocasToEscape.append(Args.begin(), Args.end()); - II->eraseFromParent(); - break; - } - } + // It's possible for a cleanup to be visited twice: it might have multiple + // cleanupret instructions. + if (FuncInfo.EHPadStateMap.count(CleanupPad)) + return; - // Finally, replace all of the temporary allocas for frame variables used in - // the outlined handlers with calls to llvm.localrecover. - for (auto &VarInfoEntry : FrameVarInfo) { - Value *ParentVal = VarInfoEntry.first; - TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second; - AllocaInst *ParentAlloca = cast<AllocaInst>(ParentVal); - - // FIXME: We should try to sink unescaped allocas from the parent frame into - // the child frame. If the alloca is escaped, we have to use the lifetime - // markers to ensure that the alloca is only live within the child frame. - - // 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) { - if (TempAlloca == getCatchObjectSentinel()) - continue; // Skip catch parameter sentinels. - Function *HandlerFn = TempAlloca->getParent()->getParent(); - llvm::Value *FP = HandlerToParentFP[HandlerFn]; - assert(FP); - - // FIXME: Sink this localrecover into the blocks where it is used. - Builder.SetInsertPoint(TempAlloca); - Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc()); - Value *RecoverArgs[] = { - Builder.CreateBitCast(&F, Int8PtrType, ""), FP, - llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)}; - Instruction *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 = cast<Instruction>( - Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType())); + int CleanupState = addUnwindMapEntry(FuncInfo, ParentState, BB); + FuncInfo.EHPadStateMap[CleanupPad] = CleanupState; + DEBUG(dbgs() << "Assigning state #" << CleanupState << " to BB " + << BB->getName() << '\n'); + for (const BasicBlock *PredBlock : predecessors(BB)) { + if ((PredBlock = getEHPadFromPredecessor(PredBlock, + CleanupPad->getParentPad()))) { + calculateCXXStateNumbers(FuncInfo, PredBlock->getFirstNonPHI(), + CleanupState); } - TempAlloca->replaceAllUsesWith(RecoveredAlloca); - TempAlloca->removeFromParent(); - RecoveredAlloca->takeName(TempAlloca); - delete TempAlloca; } - } // End for each FrameVarInfo entry. - - // Insert 'call void (...)* @llvm.localescape(...)' at the end of the entry - // block. - Builder.SetInsertPoint(&F.getEntryBlock().back()); - Builder.CreateCall(FrameEscapeFn, AllocasToEscape); - - if (SEHExceptionCodeSlot) { - if (isAllocaPromotable(SEHExceptionCodeSlot)) { - SmallPtrSet<BasicBlock *, 4> UserBlocks; - for (User *U : SEHExceptionCodeSlot->users()) { - if (auto *Inst = dyn_cast<Instruction>(U)) - UserBlocks.insert(Inst->getParent()); - } - PromoteMemToReg(SEHExceptionCodeSlot, *DT); - // After the promotion, kill off dead instructions. - for (BasicBlock *BB : UserBlocks) - SimplifyInstructionsInBlock(BB, LibInfo); + for (const User *U : CleanupPad->users()) { + const auto *UserI = cast<Instruction>(U); + if (UserI->isEHPad()) + report_fatal_error("Cleanup funclets for the MSVC++ personality cannot " + "contain exceptional actions"); } } +} - // Clean up the handler action maps we created for this function - DeleteContainerSeconds(CatchHandlerMap); - CatchHandlerMap.clear(); - DeleteContainerSeconds(CleanupHandlerMap); - CleanupHandlerMap.clear(); - HandlerToParentFP.clear(); - DT = nullptr; - LibInfo = nullptr; - SEHExceptionCodeSlot = nullptr; - EHBlocks.clear(); - NormalBlocks.clear(); - EHReturnBlocks.clear(); - - return HandlersOutlined; +static int addSEHExcept(WinEHFuncInfo &FuncInfo, int ParentState, + const Function *Filter, const BasicBlock *Handler) { + SEHUnwindMapEntry Entry; + Entry.ToState = ParentState; + Entry.IsFinally = false; + Entry.Filter = Filter; + Entry.Handler = Handler; + FuncInfo.SEHUnwindMap.push_back(Entry); + return FuncInfo.SEHUnwindMap.size() - 1; } -void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) { - // If the return values of the landing pad instruction are extracted and - // stored to memory, we want to promote the store locations to reg values. - SmallVector<AllocaInst *, 2> EHAllocas; - - // 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()) { - ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U); - if (!Extract) - continue; +static int addSEHFinally(WinEHFuncInfo &FuncInfo, int ParentState, + const BasicBlock *Handler) { + SEHUnwindMapEntry Entry; + Entry.ToState = ParentState; + Entry.IsFinally = true; + Entry.Filter = nullptr; + Entry.Handler = Handler; + FuncInfo.SEHUnwindMap.push_back(Entry); + return FuncInfo.SEHUnwindMap.size() - 1; +} - for (auto *EU : Extract->users()) { - if (auto *Store = dyn_cast<StoreInst>(EU)) { - auto *AV = cast<AllocaInst>(Store->getPointerOperand()); - EHAllocas.push_back(AV); - } +static void calculateSEHStateNumbers(WinEHFuncInfo &FuncInfo, + const Instruction *FirstNonPHI, + int ParentState) { + const BasicBlock *BB = FirstNonPHI->getParent(); + assert(BB->isEHPad() && "no a funclet!"); + + if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(FirstNonPHI)) { + assert(FuncInfo.EHPadStateMap.count(CatchSwitch) == 0 && + "shouldn't revist catch funclets!"); + + // Extract the filter function and the __except basic block and create a + // state for them. + assert(CatchSwitch->getNumHandlers() == 1 && + "SEH doesn't have multiple handlers per __try"); + const auto *CatchPad = + cast<CatchPadInst>((*CatchSwitch->handler_begin())->getFirstNonPHI()); + const BasicBlock *CatchPadBB = CatchPad->getParent(); + const Constant *FilterOrNull = + cast<Constant>(CatchPad->getArgOperand(0)->stripPointerCasts()); + const Function *Filter = dyn_cast<Function>(FilterOrNull); + assert((Filter || FilterOrNull->isNullValue()) && + "unexpected filter value"); + int TryState = addSEHExcept(FuncInfo, ParentState, Filter, CatchPadBB); + + // Everything in the __try block uses TryState as its parent state. + FuncInfo.EHPadStateMap[CatchSwitch] = TryState; + DEBUG(dbgs() << "Assigning state #" << TryState << " to BB " + << CatchPadBB->getName() << '\n'); + for (const BasicBlock *PredBlock : predecessors(BB)) + if ((PredBlock = getEHPadFromPredecessor(PredBlock, + CatchSwitch->getParentPad()))) + calculateSEHStateNumbers(FuncInfo, PredBlock->getFirstNonPHI(), + TryState); + + // Everything in the __except block unwinds to ParentState, just like code + // outside the __try. + for (const User *U : CatchPad->users()) { + const auto *UserI = cast<Instruction>(U); + if (auto *InnerCatchSwitch = dyn_cast<CatchSwitchInst>(UserI)) + if (InnerCatchSwitch->getUnwindDest() == CatchSwitch->getUnwindDest()) + calculateSEHStateNumbers(FuncInfo, UserI, ParentState); + if (auto *InnerCleanupPad = dyn_cast<CleanupPadInst>(UserI)) + if (getCleanupRetUnwindDest(InnerCleanupPad) == + CatchSwitch->getUnwindDest()) + calculateSEHStateNumbers(FuncInfo, UserI, ParentState); } - } + } else { + auto *CleanupPad = cast<CleanupPadInst>(FirstNonPHI); - // We can't do this without a dominator tree. - assert(DT); + // It's possible for a cleanup to be visited twice: it might have multiple + // cleanupret instructions. + if (FuncInfo.EHPadStateMap.count(CleanupPad)) + return; - if (!EHAllocas.empty()) { - PromoteMemToReg(EHAllocas, *DT); - EHAllocas.clear(); + int CleanupState = addSEHFinally(FuncInfo, ParentState, BB); + FuncInfo.EHPadStateMap[CleanupPad] = CleanupState; + DEBUG(dbgs() << "Assigning state #" << CleanupState << " to BB " + << BB->getName() << '\n'); + for (const BasicBlock *PredBlock : predecessors(BB)) + if ((PredBlock = + getEHPadFromPredecessor(PredBlock, CleanupPad->getParentPad()))) + calculateSEHStateNumbers(FuncInfo, PredBlock->getFirstNonPHI(), + CleanupState); + for (const User *U : CleanupPad->users()) { + const auto *UserI = cast<Instruction>(U); + if (UserI->isEHPad()) + report_fatal_error("Cleanup funclets for the SEH personality cannot " + "contain exceptional actions"); + } } +} - // After promotion, some extracts may be trivially dead. Remove them. - SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end()); - for (auto *U : Users) - RecursivelyDeleteTriviallyDeadInstructions(U); +static bool isTopLevelPadForMSVC(const Instruction *EHPad) { + if (auto *CatchSwitch = dyn_cast<CatchSwitchInst>(EHPad)) + return isa<ConstantTokenNone>(CatchSwitch->getParentPad()) && + CatchSwitch->unwindsToCaller(); + if (auto *CleanupPad = dyn_cast<CleanupPadInst>(EHPad)) + return isa<ConstantTokenNone>(CleanupPad->getParentPad()) && + getCleanupRetUnwindDest(CleanupPad) == nullptr; + if (isa<CatchPadInst>(EHPad)) + return false; + llvm_unreachable("unexpected EHPad!"); } -void WinEHPrepare::getPossibleReturnTargets(Function *ParentF, - Function *HandlerF, - SetVector<BasicBlock*> &Targets) { - for (BasicBlock &BB : *HandlerF) { - // If the handler contains landing pads, check for any - // handlers that may return directly to a block in the - // parent function. - if (auto *LPI = BB.getLandingPadInst()) { - IntrinsicInst *Recover = cast<IntrinsicInst>(LPI->getNextNode()); - SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList; - parseEHActions(Recover, ActionList); - for (const auto &Action : ActionList) { - if (auto *CH = dyn_cast<CatchHandler>(Action.get())) { - Function *NestedF = cast<Function>(CH->getHandlerBlockOrFunc()); - getPossibleReturnTargets(ParentF, NestedF, Targets); - } - } - } +void llvm::calculateSEHStateNumbers(const Function *Fn, + WinEHFuncInfo &FuncInfo) { + // Don't compute state numbers twice. + if (!FuncInfo.SEHUnwindMap.empty()) + return; - auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator()); - if (!Ret) + for (const BasicBlock &BB : *Fn) { + if (!BB.isEHPad()) continue; - - // Handler functions must always return a block address. - BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue()); - - // If this is the handler for a nested landing pad, the - // return address may have been remapped to a block in the - // parent handler. We're not interested in those. - if (BA->getFunction() != ParentF) + const Instruction *FirstNonPHI = BB.getFirstNonPHI(); + if (!isTopLevelPadForMSVC(FirstNonPHI)) continue; - - Targets.insert(BA->getBasicBlock()); + ::calculateSEHStateNumbers(FuncInfo, FirstNonPHI, -1); } + + calculateStateNumbersForInvokes(Fn, FuncInfo); } -void WinEHPrepare::completeNestedLandingPad(Function *ParentFn, - LandingPadInst *OutlinedLPad, - const LandingPadInst *OriginalLPad, - FrameVarInfoMap &FrameVarInfo) { - // Get the nested block and erase the unreachable instruction that was - // temporarily inserted as its terminator. - LLVMContext &Context = ParentFn->getContext(); - BasicBlock *OutlinedBB = OutlinedLPad->getParent(); - // If the nested landing pad was outlined before the landing pad that enclosed - // it, it will already be in outlined form. In that case, we just need to see - // if the returns and the enclosing branch instruction need to be updated. - IndirectBrInst *Branch = - dyn_cast<IndirectBrInst>(OutlinedBB->getTerminator()); - if (!Branch) { - // If the landing pad wasn't in outlined form, it should be a stub with - // an unreachable terminator. - assert(isa<UnreachableInst>(OutlinedBB->getTerminator())); - OutlinedBB->getTerminator()->eraseFromParent(); - // That should leave OutlinedLPad as the last instruction in its block. - assert(&OutlinedBB->back() == OutlinedLPad); - } +void llvm::calculateWinCXXEHStateNumbers(const Function *Fn, + WinEHFuncInfo &FuncInfo) { + // Return if it's already been done. + if (!FuncInfo.EHPadStateMap.empty()) + return; - // The original landing pad will have already had its action intrinsic - // built by the outlining loop. We need to clone that into the outlined - // location. It may also be necessary to add references to the exception - // variables to the outlined handler in which this landing pad is nested - // and remap return instructions in the nested handlers that should return - // to an address in the outlined handler. - Function *OutlinedHandlerFn = OutlinedBB->getParent(); - BasicBlock::const_iterator II = OriginalLPad; - ++II; - // The instruction after the landing pad should now be a call to eh.actions. - const Instruction *Recover = II; - const IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover); - - // Remap the return target in the nested handler. - SmallVector<BlockAddress *, 4> ActionTargets; - SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList; - parseEHActions(EHActions, ActionList); - for (const auto &Action : ActionList) { - auto *Catch = dyn_cast<CatchHandler>(Action.get()); - if (!Catch) + for (const BasicBlock &BB : *Fn) { + if (!BB.isEHPad()) continue; - // The dyn_cast to function here selects C++ catch handlers and skips - // SEH catch handlers. - auto *Handler = dyn_cast<Function>(Catch->getHandlerBlockOrFunc()); - if (!Handler) + const Instruction *FirstNonPHI = BB.getFirstNonPHI(); + if (!isTopLevelPadForMSVC(FirstNonPHI)) continue; - // Visit all the return instructions, looking for places that return - // to a location within OutlinedHandlerFn. - for (BasicBlock &NestedHandlerBB : *Handler) { - auto *Ret = dyn_cast<ReturnInst>(NestedHandlerBB.getTerminator()); - if (!Ret) - continue; - - // Handler functions must always return a block address. - BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue()); - // The original target will have been in the main parent function, - // but if it is the address of a block that has been outlined, it - // should be a block that was outlined into OutlinedHandlerFn. - assert(BA->getFunction() == ParentFn); - - // Ignore targets that aren't part of an outlined handler function. - if (!LPadTargetBlocks.count(BA->getBasicBlock())) - continue; - - // If the return value is the address ofF a block that we - // previously outlined into the parent handler function, replace - // the return instruction and add the mapped target to the list - // of possible return addresses. - BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()]; - assert(MappedBB->getParent() == OutlinedHandlerFn); - BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB); - Ret->eraseFromParent(); - ReturnInst::Create(Context, NewBA, &NestedHandlerBB); - ActionTargets.push_back(NewBA); - } - } - ActionList.clear(); - - if (Branch) { - // If the landing pad was already in outlined form, just update its targets. - for (unsigned int I = Branch->getNumDestinations(); I > 0; --I) - Branch->removeDestination(I); - // Add the previously collected action targets. - for (auto *Target : ActionTargets) - Branch->addDestination(Target->getBasicBlock()); - } else { - // If the landing pad was previously stubbed out, fill in its outlined form. - IntrinsicInst *NewEHActions = cast<IntrinsicInst>(EHActions->clone()); - OutlinedBB->getInstList().push_back(NewEHActions); - - // Insert an indirect branch into the outlined landing pad BB. - IndirectBrInst *IBr = IndirectBrInst::Create(NewEHActions, 0, OutlinedBB); - // Add the previously collected action targets. - for (auto *Target : ActionTargets) - IBr->addDestination(Target->getBasicBlock()); - } -} - -// 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; + calculateCXXStateNumbers(FuncInfo, FirstNonPHI, -1); } - return false; + calculateStateNumbersForInvokes(Fn, FuncInfo); } -static bool isCatchBlock(BasicBlock *BB) { - for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end(); - II != IE; ++II) { - if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_begincatch>())) - return true; - } - return false; -} - -static BasicBlock *createStubLandingPad(Function *Handler) { - // FIXME: Finish this! - LLVMContext &Context = Handler->getContext(); - BasicBlock *StubBB = BasicBlock::Create(Context, "stub"); - Handler->getBasicBlockList().push_back(StubBB); - IRBuilder<> Builder(StubBB); - LandingPadInst *LPad = Builder.CreateLandingPad( - llvm::StructType::get(Type::getInt8PtrTy(Context), - Type::getInt32Ty(Context), nullptr), - 0); - // Insert a call to llvm.eh.actions so that we don't try to outline this lpad. - Function *ActionIntrin = - Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::eh_actions); - Builder.CreateCall(ActionIntrin, {}, "recover"); - LPad->setCleanup(true); - Builder.CreateUnreachable(); - return StubBB; -} - -// Cycles through the blocks in an outlined handler function looking for an -// invoke instruction and inserts an invoke of llvm.donothing with an empty -// landing pad if none is found. The code that generates the .xdata tables for -// the handler needs at least one landing pad to identify the parent function's -// personality. -void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler) { - ReturnInst *Ret = nullptr; - UnreachableInst *Unreached = nullptr; - for (BasicBlock &BB : *Handler) { - TerminatorInst *Terminator = BB.getTerminator(); - // If we find an invoke, there is nothing to be done. - auto *II = dyn_cast<InvokeInst>(Terminator); - if (II) - return; - // If we've already recorded a return instruction, keep looking for invokes. - if (!Ret) - Ret = dyn_cast<ReturnInst>(Terminator); - // If we haven't recorded an unreachable instruction, try this terminator. - if (!Unreached) - Unreached = dyn_cast<UnreachableInst>(Terminator); - } - - // If we got this far, the handler contains no invokes. We should have seen - // at least one return or unreachable instruction. We'll insert an invoke of - // llvm.donothing ahead of that instruction. - assert(Ret || Unreached); - TerminatorInst *Term; - if (Ret) - Term = Ret; - else - Term = Unreached; - BasicBlock *OldRetBB = Term->getParent(); - BasicBlock *NewRetBB = SplitBlock(OldRetBB, Term, DT); - // SplitBlock adds an unconditional branch instruction at the end of the - // parent block. We want to replace that with an invoke call, so we can - // erase it now. - OldRetBB->getTerminator()->eraseFromParent(); - BasicBlock *StubLandingPad = createStubLandingPad(Handler); - Function *F = - Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing); - InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB); +static int addClrEHHandler(WinEHFuncInfo &FuncInfo, int ParentState, + ClrHandlerType HandlerType, uint32_t TypeToken, + const BasicBlock *Handler) { + ClrEHUnwindMapEntry Entry; + Entry.Parent = ParentState; + Entry.Handler = Handler; + Entry.HandlerType = HandlerType; + Entry.TypeToken = TypeToken; + FuncInfo.ClrEHUnwindMap.push_back(Entry); + return FuncInfo.ClrEHUnwindMap.size() - 1; } -// FIXME: Consider sinking this into lib/Target/X86 somehow. TargetLowering -// usually doesn't build LLVM IR, so that's probably the wrong place. -Function *WinEHPrepare::createHandlerFunc(Function *ParentFn, Type *RetTy, - const Twine &Name, Module *M, - Value *&ParentFP) { - // x64 uses a two-argument prototype where the parent FP is the second - // argument. x86 uses no arguments, just the incoming EBP value. - LLVMContext &Context = M->getContext(); - Type *Int8PtrType = Type::getInt8PtrTy(Context); - FunctionType *FnType; - if (TheTriple.getArch() == Triple::x86_64) { - Type *ArgTys[2] = {Int8PtrType, Int8PtrType}; - FnType = FunctionType::get(RetTy, ArgTys, false); - } else { - FnType = FunctionType::get(RetTy, None, false); - } - - Function *Handler = - Function::Create(FnType, GlobalVariable::InternalLinkage, Name, M); - BasicBlock *Entry = BasicBlock::Create(Context, "entry"); - Handler->getBasicBlockList().push_front(Entry); - if (TheTriple.getArch() == Triple::x86_64) { - ParentFP = &(Handler->getArgumentList().back()); - } else { - assert(M); - Function *FrameAddressFn = - Intrinsic::getDeclaration(M, Intrinsic::frameaddress); - Function *RecoverFPFn = - Intrinsic::getDeclaration(M, Intrinsic::x86_seh_recoverfp); - IRBuilder<> Builder(&Handler->getEntryBlock()); - Value *EBP = - Builder.CreateCall(FrameAddressFn, {Builder.getInt32(1)}, "ebp"); - Value *ParentI8Fn = Builder.CreateBitCast(ParentFn, Int8PtrType); - ParentFP = Builder.CreateCall(RecoverFPFn, {ParentI8Fn, EBP}); - } - return Handler; -} +void llvm::calculateClrEHStateNumbers(const Function *Fn, + WinEHFuncInfo &FuncInfo) { + // Return if it's already been done. + if (!FuncInfo.EHPadStateMap.empty()) + return; -bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn, - LandingPadInst *LPad, BasicBlock *StartBB, - FrameVarInfoMap &VarInfo) { - Module *M = SrcFn->getParent(); - LLVMContext &Context = M->getContext(); - Type *Int8PtrType = Type::getInt8PtrTy(Context); - - // Create a new function to receive the handler contents. - Value *ParentFP; - Function *Handler; - if (Action->getType() == Catch) { - Handler = createHandlerFunc(SrcFn, Int8PtrType, SrcFn->getName() + ".catch", M, - ParentFP); - } else { - Handler = createHandlerFunc(SrcFn, Type::getVoidTy(Context), - SrcFn->getName() + ".cleanup", M, ParentFP); - } - Handler->setPersonalityFn(SrcFn->getPersonalityFn()); - HandlerToParentFP[Handler] = ParentFP; - Handler->addFnAttr("wineh-parent", SrcFn->getName()); - BasicBlock *Entry = &Handler->getEntryBlock(); - - // Generate a standard prolog to setup the frame recovery structure. - IRBuilder<> Builder(Context); - Builder.SetInsertPoint(Entry); - Builder.SetCurrentDebugLocation(LPad->getDebugLoc()); - - std::unique_ptr<WinEHCloningDirectorBase> Director; - - ValueToValueMapTy VMap; - - 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, ParentFP, Sel, VarInfo, - LPadMap, NestedLPtoOriginalLP, DT, - EHBlocks)); - LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType), - ConstantInt::get(Type::getInt32Ty(Context), 1)); - } else { - Director.reset( - new WinEHCleanupDirector(Handler, ParentFP, VarInfo, LPadMap)); - LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType), - UndefValue::get(Type::getInt32Ty(Context))); - } + SmallVector<std::pair<const Instruction *, int>, 8> Worklist; - SmallVector<ReturnInst *, 8> Returns; - 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; + // Each pad needs to be able to refer to its parent, so scan the function + // looking for top-level handlers and seed the worklist with them. + for (const BasicBlock &BB : *Fn) { + if (!BB.isEHPad()) + continue; + if (BB.isLandingPad()) + report_fatal_error("CoreCLR EH cannot use landingpads"); + const Instruction *FirstNonPHI = BB.getFirstNonPHI(); + if (!isTopLevelPadForMSVC(FirstNonPHI)) + continue; + // queue this with sentinel parent state -1 to mean unwind to caller. + Worklist.emplace_back(FirstNonPHI, -1); } - // The landing pad value may be used by PHI nodes. It will ultimately be - // eliminated, but we need it in the map for intermediate handling. - VMap[LPad] = UndefValue::get(LPad->getType()); - - // Skip over PHIs and, if applicable, landingpad instructions. - II = StartBB->getFirstInsertionPt(); - - CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap, - /*ModuleLevelChanges=*/false, Returns, "", - &OutlinedFunctionInfo, Director.get()); - - // Move all the instructions in the cloned "entry" block into our entry block. - // Depending on how the parent function was laid out, the block that will - // correspond to the outlined entry block may not be the first block in the - // list. We can recognize it, however, as the cloned block which has no - // predecessors. Any other block wouldn't have been cloned if it didn't - // have a predecessor which was also cloned. - Function::iterator ClonedIt = std::next(Function::iterator(Entry)); - while (!pred_empty(ClonedIt)) - ++ClonedIt; - BasicBlock *ClonedEntryBB = ClonedIt; - assert(ClonedEntryBB); - Entry->getInstList().splice(Entry->end(), ClonedEntryBB->getInstList()); - ClonedEntryBB->eraseFromParent(); - - // Make sure we can identify the handler's personality later. - addStubInvokeToHandlerIfNeeded(Handler); - - if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) { - WinEHCatchDirector *CatchDirector = - reinterpret_cast<WinEHCatchDirector *>(Director.get()); - CatchAction->setExceptionVar(CatchDirector->getExceptionVar()); - CatchAction->setReturnTargets(CatchDirector->getReturnTargets()); - - // Look for blocks that are not part of the landing pad that we just - // outlined but terminate with a call to llvm.eh.endcatch and a - // branch to a block that is in the handler we just outlined. - // These blocks will be part of a nested landing pad that intends to - // return to an address in this handler. This case is best handled - // after both landing pads have been outlined, so for now we'll just - // save the association of the blocks in LPadTargetBlocks. The - // return instructions which are created from these branches will be - // replaced after all landing pads have been outlined. - for (const auto MapEntry : VMap) { - // VMap maps all values and blocks that were just cloned, but dead - // blocks which were pruned will map to nullptr. - if (!isa<BasicBlock>(MapEntry.first) || MapEntry.second == nullptr) + while (!Worklist.empty()) { + const Instruction *Pad; + int ParentState; + std::tie(Pad, ParentState) = Worklist.pop_back_val(); + + Value *ParentPad; + int PredState; + if (const CleanupPadInst *Cleanup = dyn_cast<CleanupPadInst>(Pad)) { + // A cleanup can have multiple exits; don't re-process after the first. + if (FuncInfo.EHPadStateMap.count(Cleanup)) continue; - const BasicBlock *MappedBB = cast<BasicBlock>(MapEntry.first); - for (auto *Pred : predecessors(const_cast<BasicBlock *>(MappedBB))) { - auto *Branch = dyn_cast<BranchInst>(Pred->getTerminator()); - if (!Branch || !Branch->isUnconditional() || Pred->size() <= 1) - continue; - BasicBlock::iterator II = const_cast<BranchInst *>(Branch); - --II; - if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_endcatch>())) { - // This would indicate that a nested landing pad wants to return - // to a block that is outlined into two different handlers. - assert(!LPadTargetBlocks.count(MappedBB)); - LPadTargetBlocks[MappedBB] = cast<BasicBlock>(MapEntry.second); + // CoreCLR personality uses arity to distinguish faults from finallies. + const BasicBlock *PadBlock = Cleanup->getParent(); + ClrHandlerType HandlerType = + (Cleanup->getNumOperands() ? ClrHandlerType::Fault + : ClrHandlerType::Finally); + int NewState = + addClrEHHandler(FuncInfo, ParentState, HandlerType, 0, PadBlock); + FuncInfo.EHPadStateMap[Cleanup] = NewState; + // Propagate the new state to all preds of the cleanup + ParentPad = Cleanup->getParentPad(); + PredState = NewState; + } else if (const auto *CatchSwitch = dyn_cast<CatchSwitchInst>(Pad)) { + SmallVector<const CatchPadInst *, 1> Handlers; + for (const BasicBlock *CatchPadBB : CatchSwitch->handlers()) { + const auto *Catch = cast<CatchPadInst>(CatchPadBB->getFirstNonPHI()); + Handlers.push_back(Catch); + } + FuncInfo.EHPadStateMap[CatchSwitch] = ParentState; + int NewState = ParentState; + for (auto HandlerI = Handlers.rbegin(), HandlerE = Handlers.rend(); + HandlerI != HandlerE; ++HandlerI) { + const CatchPadInst *Catch = *HandlerI; + const BasicBlock *PadBlock = Catch->getParent(); + uint32_t TypeToken = static_cast<uint32_t>( + cast<ConstantInt>(Catch->getArgOperand(0))->getZExtValue()); + NewState = addClrEHHandler(FuncInfo, NewState, ClrHandlerType::Catch, + TypeToken, PadBlock); + FuncInfo.EHPadStateMap[Catch] = NewState; + } + for (const auto *CatchPad : Handlers) { + for (const User *U : CatchPad->users()) { + const auto *UserI = cast<Instruction>(U); + if (UserI->isEHPad()) + Worklist.emplace_back(UserI, ParentState); } } + PredState = NewState; + ParentPad = CatchSwitch->getParentPad(); + } else { + llvm_unreachable("Unexpected EH pad"); } - } // End if (CatchAction) - - Action->setHandlerBlockOrFunc(Handler); - - return true; -} - -/// 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 = SplitBlock(StartBB, StartBB->getFirstInsertionPt(), DT); - } - IRBuilder<> Builder(HandlerBB->getFirstInsertionPt()); - Function *EHCodeFn = Intrinsic::getDeclaration( - StartBB->getParent()->getParent(), Intrinsic::eh_exceptioncode); - Value *Code = Builder.CreateCall(EHCodeFn, {}, "sehcode"); - Code = Builder.CreateIntToPtr(Code, SEHExceptionCodeSlot->getAllocatedType()); - Builder.CreateStore(Code, SEHExceptionCodeSlot); - CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB)); - TinyPtrVector<BasicBlock *> Targets(HandlerBB); - CatchAction->setReturnTargets(Targets); -} -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 will have been promoted to reg values before - // this routine is called. - 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) { - ExtractedEHPtrs.push_back(Extract); - } else if (Idx == 1) { - ExtractedSelectors.push_back(Extract); + // Queue all predecessors with the given state + for (const BasicBlock *Pred : predecessors(Pad->getParent())) { + if ((Pred = getEHPadFromPredecessor(Pred, ParentPad))) + Worklist.emplace_back(Pred->getFirstNonPHI(), PredState); } } -} -bool LandingPadMap::isOriginLandingPadBlock(const BasicBlock *BB) const { - return BB->getLandingPadInst() == OriginLPad; + calculateStateNumbersForInvokes(Fn, FuncInfo); } -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; - } - return false; -} - -void LandingPadMap::remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue, - Value *SelectorValue) const { - // Remap all landing pad extract instructions to the specified values. - for (auto *Extract : ExtractedEHPtrs) - VMap[Extract] = EHPtrValue; - for (auto *Extract : ExtractedSelectors) - VMap[Extract] = SelectorValue; -} - -static bool isLocalAddressCall(const Value *V) { - return match(const_cast<Value *>(V), m_Intrinsic<Intrinsic::localaddress>()); -} - -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; - - // Nested landing pads that have not already been outlined 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 *LPad = dyn_cast<LandingPadInst>(Inst)) { - return handleLandingPad(VMap, LPad, NewBB); - } +void WinEHPrepare::colorFunclets(Function &F) { + BlockColors = colorEHFunclets(F); - // Nested landing pads that have already been outlined will be cloned in their - // outlined form, but we need to intercept the ibr instruction to filter out - // targets that do not return to the handler we are outlining. - if (auto *IBr = dyn_cast<IndirectBrInst>(Inst)) { - return handleIndirectBr(VMap, IBr, NewBB); - } - - 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 (auto *Cmp = dyn_cast<CmpInst>(Inst)) - return handleCompare(VMap, Cmp, 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); - - // When outlining llvm.localaddress(), remap that to the second argument, - // which is the FP of the parent. - if (isLocalAddressCall(Inst)) { - VMap[Inst] = ParentFP; - return CloningDirector::SkipInstruction; - } - - // Continue with the default cloning behavior. - return CloningDirector::CloneInstruction; -} - -CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad( - ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) { - // If the instruction after the landing pad is a call to llvm.eh.actions - // the landing pad has already been outlined. In this case, we should - // clone it because it may return to a block in the handler we are - // outlining now that would otherwise be unreachable. The landing pads - // are sorted before outlining begins to enable this case to work - // properly. - const Instruction *NextI = LPad->getNextNode(); - if (match(NextI, m_Intrinsic<Intrinsic::eh_actions>())) - return CloningDirector::CloneInstruction; - - // If the landing pad hasn't been outlined yet, the landing pad we are - // outlining now does not dominate it and so it cannot return to a block - // in this handler. In that case, we can just insert a stub landing - // pad now and patch it up later. - Instruction *NewInst = LPad->clone(); - if (LPad->hasName()) - NewInst->setName(LPad->getName()); - // Save this correlation for later processing. - NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad; - VMap[LPad] = NewInst; - BasicBlock::InstListType &InstList = NewBB->getInstList(); - InstList.push_back(NewInst); - InstList.push_back(new UnreachableInst(NewBB->getContext())); - return CloningDirector::StopCloningBB; -} - -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(); - if (isa<ConstantPointerNull>(ExceptionObjectVar)) - return CloningDirector::SkipInstruction; - assert(cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() && - "catch parameter is not static alloca"); - Materializer.escapeCatchObject(ExceptionObjectVar); - 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. However, a catch-all handler may call - // end catch from the original landing pad. If the call occurs in a nested - // landing pad block, we must skip it and continue so that the landing pad - // gets cloned. - auto *ParentBB = IntrinCall->getParent(); - if (ParentBB->isLandingPad() && !LPadMap.isOriginLandingPadBlock(ParentBB)) - return CloningDirector::SkipInstruction; - - // If an end catch occurs anywhere else we want to terminate the handler - // with a return to the code that follows the endcatch call. If the - // next instruction is not an unconditional branch, we need to split the - // block to provide a clear target for the return instruction. - BasicBlock *ContinueBB; - auto Next = std::next(BasicBlock::const_iterator(IntrinCall)); - const BranchInst *Branch = dyn_cast<BranchInst>(Next); - if (!Branch || !Branch->isUnconditional()) { - // We're interrupting the cloning process at this location, so the - // const_cast we're doing here will not cause a problem. - ContinueBB = SplitBlock(const_cast<BasicBlock *>(ParentBB), - const_cast<Instruction *>(cast<Instruction>(Next))); - } else { - ContinueBB = Branch->getSuccessor(0); + // Invert the map from BB to colors to color to BBs. + for (BasicBlock &BB : F) { + ColorVector &Colors = BlockColors[&BB]; + for (BasicBlock *Color : Colors) + FuncletBlocks[Color].push_back(&BB); } - - ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueBB), NewBB); - ReturnTargets.push_back(ContinueBB); - - // 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::handleIndirectBr( - ValueToValueMapTy &VMap, - const IndirectBrInst *IBr, - BasicBlock *NewBB) { - // If this indirect branch is not part of a landing pad block, just clone it. - const BasicBlock *ParentBB = IBr->getParent(); - if (!ParentBB->isLandingPad()) - return CloningDirector::CloneInstruction; - - // If it is part of a landing pad, we want to filter out target blocks - // that are not part of the handler we are outlining. - const LandingPadInst *LPad = ParentBB->getLandingPadInst(); - - // Save this correlation for later processing. - NestedLPtoOriginalLP[cast<LandingPadInst>(VMap[LPad])] = LPad; - - // We should only get here for landing pads that have already been outlined. - assert(match(LPad->getNextNode(), m_Intrinsic<Intrinsic::eh_actions>())); - - // Copy the indirectbr, but only include targets that were previously - // identified as EH blocks and are dominated by the nested landing pad. - SetVector<const BasicBlock *> ReturnTargets; - for (int I = 0, E = IBr->getNumDestinations(); I < E; ++I) { - auto *TargetBB = IBr->getDestination(I); - if (EHBlocks.count(const_cast<BasicBlock*>(TargetBB)) && - DT->dominates(ParentBB, TargetBB)) { - DEBUG(dbgs() << " Adding destination " << TargetBB->getName() << "\n"); - ReturnTargets.insert(TargetBB); - } +void llvm::calculateCatchReturnSuccessorColors(const Function *Fn, + WinEHFuncInfo &FuncInfo) { + for (const BasicBlock &BB : *Fn) { + const auto *CatchRet = dyn_cast<CatchReturnInst>(BB.getTerminator()); + if (!CatchRet) + continue; + // A 'catchret' returns to the outer scope's color. + Value *ParentPad = CatchRet->getParentPad(); + const BasicBlock *Color; + if (isa<ConstantTokenNone>(ParentPad)) + Color = &Fn->getEntryBlock(); + else + Color = cast<Instruction>(ParentPad)->getParent(); + // Record the catchret successor's funclet membership. + FuncInfo.CatchRetSuccessorColorMap[CatchRet] = Color; } - IndirectBrInst *NewBranch = - IndirectBrInst::Create(const_cast<Value *>(IBr->getAddress()), - ReturnTargets.size(), NewBB); - for (auto *Target : ReturnTargets) - NewBranch->addDestination(const_cast<BasicBlock*>(Target)); - - // The operands and targets of the branch instruction are remapped later - // because it is a terminator. Tell the cloning code to clone the - // blocks we just added to the target list. - return CloningDirector::CloneSuccessors; } -CloningDirector::CloningAction -WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap, - const InvokeInst *Invoke, BasicBlock *NewBB) { - return CloningDirector::CloneInstruction; -} +void WinEHPrepare::demotePHIsOnFunclets(Function &F) { + // Strip PHI nodes off of EH pads. + SmallVector<PHINode *, 16> PHINodes; + for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) { + BasicBlock *BB = &*FI++; + if (!BB->isEHPad()) + continue; + for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) { + Instruction *I = &*BI++; + auto *PN = dyn_cast<PHINode>(I); + // Stop at the first non-PHI. + if (!PN) + break; -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; -} + AllocaInst *SpillSlot = insertPHILoads(PN, F); + if (SpillSlot) + insertPHIStores(PN, SpillSlot); -CloningDirector::CloningAction -WinEHCatchDirector::handleCompare(ValueToValueMapTy &VMap, - const CmpInst *Compare, BasicBlock *NewBB) { - const IntrinsicInst *IntrinCall = nullptr; - if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>())) { - IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(0)); - } else if (match(Compare->getOperand(1), - m_Intrinsic<Intrinsic::eh_typeid_for>())) { - IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(1)); - } - if (IntrinCall) { - 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->stripPointerCasts()) { - VMap[Compare] = ConstantInt::get(SelectorIDType, 1); - } else { - VMap[Compare] = ConstantInt::get(SelectorIDType, 0); + PHINodes.push_back(PN); } - return CloningDirector::SkipInstruction; } - return CloningDirector::CloneInstruction; -} -CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad( - ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) { - // The MS runtime will terminate the process if an exception occurs in a - // cleanup handler, so we shouldn't encounter landing pads in the actual - // cleanup code, but they may appear in catch blocks. Depending on where - // we started cloning we may see one, but it will get dropped during dead - // block pruning. - Instruction *NewInst = new UnreachableInst(NewBB->getContext()); - VMap[LPad] = NewInst; - BasicBlock::InstListType &InstList = NewBB->getInstList(); - InstList.push_back(NewInst); - return CloningDirector::StopCloningBB; -} - -CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch( - ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { - // Cleanup code may flow into catch blocks or the catch block may be part - // of a branch that will be optimized away. We'll insert a return - // instruction now, but it may be pruned before the cloning process is - // complete. - ReturnInst::Create(NewBB->getContext(), nullptr, NewBB); - return CloningDirector::StopCloningBB; -} - -CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch( - ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { - // Cleanup handlers nested within catch handlers may begin with a call to - // eh.endcatch. We can just ignore that instruction. - return CloningDirector::SkipInstruction; -} - -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::handleIndirectBr( - ValueToValueMapTy &VMap, - const IndirectBrInst *IBr, - BasicBlock *NewBB) { - // No special handling is required for cleanup cloning. - return CloningDirector::CloneInstruction; -} - -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; - - // Remap the operands. - llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer); - - // 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::CloneSuccessors; -} - -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; -} - -CloningDirector::CloningAction -WinEHCleanupDirector::handleCompare(ValueToValueMapTy &VMap, - const CmpInst *Compare, BasicBlock *NewBB) { - if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>()) || - match(Compare->getOperand(1), m_Intrinsic<Intrinsic::eh_typeid_for>())) { - VMap[Compare] = ConstantInt::get(SelectorIDType, 1); - return CloningDirector::SkipInstruction; + for (auto *PN : PHINodes) { + // There may be lingering uses on other EH PHIs being removed + PN->replaceAllUsesWith(UndefValue::get(PN->getType())); + PN->eraseFromParent(); } - return CloningDirector::CloneInstruction; -} - -WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer( - Function *OutlinedFn, Value *ParentFP, FrameVarInfoMap &FrameVarInfo) - : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) { - BasicBlock *EntryBB = &OutlinedFn->getEntryBlock(); - - // New allocas should be inserted in the entry block, but after the parent FP - // is established if it is an instruction. - Instruction *InsertPoint = EntryBB->getFirstInsertionPt(); - if (auto *FPInst = dyn_cast<Instruction>(ParentFP)) - InsertPoint = FPInst->getNextNode(); - Builder.SetInsertPoint(EntryBB, InsertPoint); } -Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) { - // If we're asked to materialize a static alloca, we temporarily create an - // alloca in the outlined function and add this to the FrameVarInfo map. When - // all the outlining is complete, we'll replace these temporary allocas with - // calls to llvm.localrecover. - if (auto *AV = dyn_cast<AllocaInst>(V)) { - assert(AV->isStaticAlloca() && - "cannot materialize un-demoted dynamic alloca"); - AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone()); - Builder.Insert(NewAlloca, AV->getName()); - FrameVarInfo[AV].push_back(NewAlloca); - return NewAlloca; - } - - if (isa<Instruction>(V) || isa<Argument>(V)) { - Function *Parent = isa<Instruction>(V) - ? cast<Instruction>(V)->getParent()->getParent() - : cast<Argument>(V)->getParent(); - errs() - << "Failed to demote instruction used in exception handler of function " - << GlobalValue::getRealLinkageName(Parent->getName()) << ":\n"; - errs() << " " << *V << '\n'; - report_fatal_error("WinEHPrepare failed to demote instruction"); - } - - // Don't materialize other values. - return nullptr; -} +void WinEHPrepare::cloneCommonBlocks(Function &F) { + // We need to clone all blocks which belong to multiple funclets. Values are + // remapped throughout the funclet to propogate both the new instructions + // *and* the new basic blocks themselves. + for (auto &Funclets : FuncletBlocks) { + BasicBlock *FuncletPadBB = Funclets.first; + std::vector<BasicBlock *> &BlocksInFunclet = Funclets.second; + + std::vector<std::pair<BasicBlock *, BasicBlock *>> Orig2Clone; + ValueToValueMapTy VMap; + for (BasicBlock *BB : BlocksInFunclet) { + ColorVector &ColorsForBB = BlockColors[BB]; + // We don't need to do anything if the block is monochromatic. + size_t NumColorsForBB = ColorsForBB.size(); + if (NumColorsForBB == 1) + continue; -void WinEHFrameVariableMaterializer::escapeCatchObject(Value *V) { - // Catch parameter objects have to live in the parent frame. When we see a use - // of a catch parameter, add a sentinel to the multimap to indicate that it's - // used from another handler. This will prevent us from trying to sink the - // alloca into the handler and ensure that the catch parameter is present in - // the call to llvm.localescape. - FrameVarInfo[V].push_back(getCatchObjectSentinel()); -} + DEBUG_WITH_TYPE("winehprepare-coloring", + dbgs() << " Cloning block \'" << BB->getName() + << "\' for funclet \'" << FuncletPadBB->getName() + << "\'.\n"); -// 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) { - findCleanupHandlers(Actions, BB, nullptr); - return; - } + // Create a new basic block and copy instructions into it! + BasicBlock *CBB = + CloneBasicBlock(BB, VMap, Twine(".for.", FuncletPadBB->getName())); + // Insert the clone immediately after the original to ensure determinism + // and to keep the same relative ordering of any funclet's blocks. + CBB->insertInto(&F, BB->getNextNode()); - VisitedBlockSet VisitedBlocks; + // Add basic block mapping. + VMap[BB] = CBB; - while (HandlersFound != NumClauses) { - BasicBlock *NextBB = nullptr; + // Record delta operations that we need to perform to our color mappings. + Orig2Clone.emplace_back(BB, CBB); + } - // Skip over filter clauses. - if (LPad->isFilter(HandlersFound)) { - ++HandlersFound; + // If nothing was cloned, we're done cloning in this funclet. + if (Orig2Clone.empty()) continue; + + // Update our color mappings to reflect that one block has lost a color and + // another has gained a color. + for (auto &BBMapping : Orig2Clone) { + BasicBlock *OldBlock = BBMapping.first; + BasicBlock *NewBlock = BBMapping.second; + + BlocksInFunclet.push_back(NewBlock); + ColorVector &NewColors = BlockColors[NewBlock]; + assert(NewColors.empty() && "A new block should only have one color!"); + NewColors.push_back(FuncletPadBB); + + DEBUG_WITH_TYPE("winehprepare-coloring", + dbgs() << " Assigned color \'" << FuncletPadBB->getName() + << "\' to block \'" << NewBlock->getName() + << "\'.\n"); + + BlocksInFunclet.erase( + std::remove(BlocksInFunclet.begin(), BlocksInFunclet.end(), OldBlock), + BlocksInFunclet.end()); + ColorVector &OldColors = BlockColors[OldBlock]; + OldColors.erase( + std::remove(OldColors.begin(), OldColors.end(), FuncletPadBB), + OldColors.end()); + + DEBUG_WITH_TYPE("winehprepare-coloring", + dbgs() << " Removed color \'" << FuncletPadBB->getName() + << "\' from block \'" << OldBlock->getName() + << "\'.\n"); } - // See if the clause we're looking for is a catch-all. - // If so, the catch begins immediately. - Constant *ExpectedSelector = - LPad->getClause(HandlersFound)->stripPointerCasts(); - if (isa<ConstantPointerNull>(ExpectedSelector)) { - // The catch all must occur last. - assert(HandlersFound == NumClauses - 1); - - // There can be additional selector dispatches in the call chain that we - // need to ignore. - BasicBlock *CatchBlock = nullptr; - Constant *Selector; - while (BB && isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) { - DEBUG(dbgs() << " Found extra catch dispatch in block " - << CatchBlock->getName() << "\n"); - BB = NextBB; + // Loop over all of the instructions in this funclet, fixing up operand + // references as we go. This uses VMap to do all the hard work. + for (BasicBlock *BB : BlocksInFunclet) + // Loop over all instructions, fixing each one as we find it... + for (Instruction &I : *BB) + RemapInstruction(&I, VMap, + RF_IgnoreMissingEntries | RF_NoModuleLevelChanges); + + auto UpdatePHIOnClonedBlock = [&](PHINode *PN, bool IsForOldBlock) { + unsigned NumPreds = PN->getNumIncomingValues(); + for (unsigned PredIdx = 0, PredEnd = NumPreds; PredIdx != PredEnd; + ++PredIdx) { + BasicBlock *IncomingBlock = PN->getIncomingBlock(PredIdx); + ColorVector &IncomingColors = BlockColors[IncomingBlock]; + bool BlockInFunclet = IncomingColors.size() == 1 && + IncomingColors.front() == FuncletPadBB; + if (IsForOldBlock != BlockInFunclet) + continue; + PN->removeIncomingValue(IncomingBlock, /*DeletePHIIfEmpty=*/false); + // Revisit the next entry. + --PredIdx; + --PredEnd; } - - // Add the catch handler to the action list. - CatchHandler *Action = nullptr; - if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) { - // If the CatchHandlerMap already has an entry for this BB, re-use it. - Action = CatchHandlerMap[BB]; - assert(Action->getSelector() == ExpectedSelector); - } else { - // We don't expect a selector dispatch, but there may be a call to - // llvm.eh.begincatch, which separates catch handling code from - // cleanup code in the same control flow. This call looks for the - // begincatch intrinsic. - Action = findCatchHandler(BB, NextBB, VisitedBlocks); - if (Action) { - // 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) - findCleanupHandlers(Actions, BB, BB); - } else { - // If an action was not found, it means that the control flows - // directly into the catch-all handler and there is no cleanup code. - // That's an expected situation and we must create a catch action. - // Since this is a catch-all handler, the selector won't actually - // appear in the code anywhere. ExpectedSelector here is the constant - // null ptr that we got from the landing pad instruction. - Action = new CatchHandler(BB, ExpectedSelector, nullptr); - CatchHandlerMap[BB] = Action; - } + }; + + for (auto &BBMapping : Orig2Clone) { + BasicBlock *OldBlock = BBMapping.first; + BasicBlock *NewBlock = BBMapping.second; + for (Instruction &OldI : *OldBlock) { + auto *OldPN = dyn_cast<PHINode>(&OldI); + if (!OldPN) + break; + UpdatePHIOnClonedBlock(OldPN, /*IsForOldBlock=*/true); } - 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); - assert(CatchAction); - - // See if there is any interesting code executed before the dispatch. - findCleanupHandlers(Actions, BB, CatchAction->getStartBlock()); - - // When the source program contains multiple nested try blocks the catch - // handlers can get strung together in such a way that we can encounter - // a dispatch for a selector that we've already had a handler for. - if (CatchAction->getSelector()->stripPointerCasts() == ExpectedSelector) { - ++HandlersFound; - - // Add the catch handler to the action list. - DEBUG(dbgs() << " Found catch dispatch in block " - << CatchAction->getStartBlock()->getName() << "\n"); - Actions.insertCatchHandler(CatchAction); - } else { - // Under some circumstances optimized IR will flow unconditionally into a - // handler block without checking the selector. This can only happen if - // the landing pad has a catch-all handler and the handler for the - // preceeding catch clause is identical to the catch-call handler - // (typically an empty catch). In this case, the handler must be shared - // by all remaining clauses. - if (isa<ConstantPointerNull>( - CatchAction->getSelector()->stripPointerCasts())) { - DEBUG(dbgs() << " Applying early catch-all handler in block " - << CatchAction->getStartBlock()->getName() - << " to all remaining clauses.\n"); - Actions.insertCatchHandler(CatchAction); - return; + for (Instruction &NewI : *NewBlock) { + auto *NewPN = dyn_cast<PHINode>(&NewI); + if (!NewPN) + break; + UpdatePHIOnClonedBlock(NewPN, /*IsForOldBlock=*/false); } - - DEBUG(dbgs() << " Found extra 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. - findCleanupHandlers(Actions, BB, BB); - - // 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; - } + // Check to see if SuccBB has PHI nodes. If so, we need to add entries to + // the PHI nodes for NewBB now. + for (auto &BBMapping : Orig2Clone) { + BasicBlock *OldBlock = BBMapping.first; + BasicBlock *NewBlock = BBMapping.second; + for (BasicBlock *SuccBB : successors(NewBlock)) { + for (Instruction &SuccI : *SuccBB) { + auto *SuccPN = dyn_cast<PHINode>(&SuccI); + if (!SuccPN) + break; + + // Ok, we have a PHI node. Figure out what the incoming value was for + // the OldBlock. + int OldBlockIdx = SuccPN->getBasicBlockIndex(OldBlock); + if (OldBlockIdx == -1) + break; + Value *IV = SuccPN->getIncomingValue(OldBlockIdx); + + // Remap the value if necessary. + if (auto *Inst = dyn_cast<Instruction>(IV)) { + ValueToValueMapTy::iterator I = VMap.find(Inst); + if (I != VMap.end()) + IV = I->second; + } - // 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; - } - // If we encounter a block containing an llvm.eh.begincatch before we - // find a selector dispatch block, the handler is assumed to be - // reached unconditionally. This happens for catch-all blocks, but - // it can also happen for other catch handlers that have been combined - // with the catch-all handler during optimization. - if (isCatchBlock(BB)) { - PointerType *Int8PtrTy = Type::getInt8PtrTy(BB->getContext()); - Constant *NullSelector = ConstantPointerNull::get(Int8PtrTy); - CatchHandler *Action = new CatchHandler(BB, NullSelector, nullptr); - CatchHandlerMap[BB] = Action; - return Action; + SuccPN->addIncoming(IV, NewBlock); + } + } } - } - // 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; + for (ValueToValueMapTy::value_type VT : VMap) { + // If there were values defined in BB that are used outside the funclet, + // then we now have to update all uses of the value to use either the + // original value, the cloned value, or some PHI derived value. This can + // require arbitrary PHI insertion, of which we are prepared to do, clean + // these up now. + SmallVector<Use *, 16> UsesToRename; - CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks); - if (Action) - return Action; - } - return nullptr; -} - -// These are helper functions to combine repeated code from findCleanupHandlers. -static void createCleanupHandler(LandingPadActions &Actions, - CleanupHandlerMapTy &CleanupHandlerMap, - BasicBlock *BB) { - CleanupHandler *Action = new CleanupHandler(BB); - CleanupHandlerMap[BB] = Action; - Actions.insertCleanupHandler(Action); - DEBUG(dbgs() << " Found cleanup code in block " - << Action->getStartBlock()->getName() << "\n"); -} - -static CallSite matchOutlinedFinallyCall(BasicBlock *BB, - Instruction *MaybeCall) { - // Look for finally blocks that Clang has already outlined for us. - // %fp = call i8* @llvm.localaddress() - // call void @"fin$parent"(iN 1, i8* %fp) - if (isLocalAddressCall(MaybeCall) && MaybeCall != BB->getTerminator()) - MaybeCall = MaybeCall->getNextNode(); - CallSite FinallyCall(MaybeCall); - if (!FinallyCall || FinallyCall.arg_size() != 2) - return CallSite(); - if (!match(FinallyCall.getArgument(0), m_SpecificInt(1))) - return CallSite(); - if (!isLocalAddressCall(FinallyCall.getArgument(1))) - return CallSite(); - return FinallyCall; -} - -static BasicBlock *followSingleUnconditionalBranches(BasicBlock *BB) { - // Skip single ubr blocks. - while (BB->getFirstNonPHIOrDbg() == BB->getTerminator()) { - auto *Br = dyn_cast<BranchInst>(BB->getTerminator()); - if (Br && Br->isUnconditional()) - BB = Br->getSuccessor(0); - else - return BB; - } - return BB; -} - -// 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. -// -void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions, - 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) { - BB = followSingleUnconditionalBranches(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]) { - Actions.insertCleanupHandler(Action); - DEBUG(dbgs() << " Found cleanup code in block " - << Action->getStartBlock()->getName() << "\n"); - // FIXME: This cleanup might chain into another, and we need to discover - // that. - return; - } 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 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. - BasicBlock *SuccBB = followSingleUnconditionalBranches(BB); - if (SuccBB == BB || SuccBB == EndBB) - return; - BB = SuccBB; + auto *OldI = dyn_cast<Instruction>(const_cast<Value *>(VT.first)); + if (!OldI) continue; + auto *NewI = cast<Instruction>(VT.second); + // Scan all uses of this instruction to see if it is used outside of its + // funclet, and if so, record them in UsesToRename. + for (Use &U : OldI->uses()) { + Instruction *UserI = cast<Instruction>(U.getUser()); + BasicBlock *UserBB = UserI->getParent(); + ColorVector &ColorsForUserBB = BlockColors[UserBB]; + assert(!ColorsForUserBB.empty()); + if (ColorsForUserBB.size() > 1 || + *ColorsForUserBB.begin() != FuncletPadBB) + UsesToRename.push_back(&U); } - } - // 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; + // If there are no uses outside the block, we're done with this + // instruction. + if (UsesToRename.empty()) + continue; - TerminatorInst *Terminator = BB->getTerminator(); + // We found a use of OldI outside of the funclet. Rename all uses of OldI + // that are outside its funclet to be uses of the appropriate PHI node + // etc. + SSAUpdater SSAUpdate; + SSAUpdate.Initialize(OldI->getType(), OldI->getName()); + SSAUpdate.AddAvailableValue(OldI->getParent(), OldI); + SSAUpdate.AddAvailableValue(NewI->getParent(), NewI); - // 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); + while (!UsesToRename.empty()) + SSAUpdate.RewriteUseAfterInsertions(*UsesToRename.pop_back_val()); } + } +} - // Look for the bare resume pattern: - // %lpad.val1 = insertvalue { i8*, i32 } undef, i8* %exn, 0 - // %lpad.val2 = insertvalue { i8*, i32 } %lpad.val1, i32 %sel, 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 the resume value isn't a phi or landingpad value, it should be a - // series of insertions. Identify them so we can avoid them when scanning - // for cleanups. - if (!isa<PHINode>(ResumeVal) && !isa<LandingPadInst>(ResumeVal)) { - Insert2 = dyn_cast<InsertValueInst>(ResumeVal); - if (!Insert2) - return createCleanupHandler(Actions, CleanupHandlerMap, BB); - Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand()); - if (!Insert1) - return createCleanupHandler(Actions, 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) +void WinEHPrepare::removeImplausibleInstructions(Function &F) { + // Remove implausible terminators and replace them with UnreachableInst. + for (auto &Funclet : FuncletBlocks) { + BasicBlock *FuncletPadBB = Funclet.first; + std::vector<BasicBlock *> &BlocksInFunclet = Funclet.second; + Instruction *FirstNonPHI = FuncletPadBB->getFirstNonPHI(); + auto *FuncletPad = dyn_cast<FuncletPadInst>(FirstNonPHI); + auto *CatchPad = dyn_cast_or_null<CatchPadInst>(FuncletPad); + auto *CleanupPad = dyn_cast_or_null<CleanupPadInst>(FuncletPad); + + for (BasicBlock *BB : BlocksInFunclet) { + for (Instruction &I : *BB) { + CallSite CS(&I); + if (!CS) continue; - if (!Inst->hasOneUse() || - (Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) { - return createCleanupHandler(Actions, CleanupHandlerMap, BB); - } - } - return; - } - BranchInst *Branch = dyn_cast<BranchInst>(Terminator); - if (Branch && Branch->isConditional()) { - // Look for the selector dispatch. - // %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*)) - // %matches = icmp eq i32 %sel, %2 - // br i1 %matches, label %catch14, label %eh.resume - CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition()); - if (!Compare || !Compare->isEquality()) - return createCleanupHandler(Actions, 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) + Value *FuncletBundleOperand = nullptr; + if (auto BU = CS.getOperandBundle(LLVMContext::OB_funclet)) + FuncletBundleOperand = BU->Inputs.front(); + + if (FuncletBundleOperand == FuncletPad) continue; - if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) + + // Skip call sites which are nounwind intrinsics. + auto *CalledFn = + dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); + if (CalledFn && CalledFn->isIntrinsic() && CS.doesNotThrow()) continue; - return createCleanupHandler(Actions, CleanupHandlerMap, BB); - } - // The selector dispatch block should always terminate our search. - assert(BB == EndBB); - return; - } - if (isAsynchronousEHPersonality(Personality)) { - // If this is a landingpad block, split the block at the first non-landing - // pad instruction. - Instruction *MaybeCall = BB->getFirstNonPHIOrDbg(); - if (LPadMap) { - while (MaybeCall != BB->getTerminator() && - LPadMap->isLandingPadSpecificInst(MaybeCall)) - MaybeCall = MaybeCall->getNextNode(); + // This call site was not part of this funclet, remove it. + if (CS.isInvoke()) { + // Remove the unwind edge if it was an invoke. + removeUnwindEdge(BB); + // Get a pointer to the new call. + BasicBlock::iterator CallI = + std::prev(BB->getTerminator()->getIterator()); + auto *CI = cast<CallInst>(&*CallI); + changeToUnreachable(CI, /*UseLLVMTrap=*/false); + } else { + changeToUnreachable(&I, /*UseLLVMTrap=*/false); + } + + // There are no more instructions in the block (except for unreachable), + // we are done. + break; } - // Look for outlined finally calls on x64, since those happen to match the - // prototype provided by the runtime. - if (TheTriple.getArch() == Triple::x86_64) { - if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) { - Function *Fin = FinallyCall.getCalledFunction(); - assert(Fin && "outlined finally call should be direct"); - auto *Action = new CleanupHandler(BB); - Action->setHandlerBlockOrFunc(Fin); - Actions.insertCleanupHandler(Action); - CleanupHandlerMap[BB] = Action; - DEBUG(dbgs() << " Found frontend-outlined finally call to " - << Fin->getName() << " in block " - << Action->getStartBlock()->getName() << "\n"); - - // Split the block if there were more interesting instructions and - // look for finally calls in the normal successor block. - BasicBlock *SuccBB = BB; - if (FinallyCall.getInstruction() != BB->getTerminator() && - FinallyCall.getInstruction()->getNextNode() != - BB->getTerminator()) { - SuccBB = - SplitBlock(BB, FinallyCall.getInstruction()->getNextNode(), DT); - } else { - if (FinallyCall.isInvoke()) { - SuccBB = cast<InvokeInst>(FinallyCall.getInstruction()) - ->getNormalDest(); - } else { - SuccBB = BB->getUniqueSuccessor(); - assert(SuccBB && - "splitOutlinedFinallyCalls didn't insert a branch"); - } - } - BB = SuccBB; - if (BB == EndBB) - return; - continue; + TerminatorInst *TI = BB->getTerminator(); + // CatchPadInst and CleanupPadInst can't transfer control to a ReturnInst. + bool IsUnreachableRet = isa<ReturnInst>(TI) && FuncletPad; + // The token consumed by a CatchReturnInst must match the funclet token. + bool IsUnreachableCatchret = false; + if (auto *CRI = dyn_cast<CatchReturnInst>(TI)) + IsUnreachableCatchret = CRI->getCatchPad() != CatchPad; + // The token consumed by a CleanupReturnInst must match the funclet token. + bool IsUnreachableCleanupret = false; + if (auto *CRI = dyn_cast<CleanupReturnInst>(TI)) + IsUnreachableCleanupret = CRI->getCleanupPad() != CleanupPad; + if (IsUnreachableRet || IsUnreachableCatchret || + IsUnreachableCleanupret) { + changeToUnreachable(TI, /*UseLLVMTrap=*/false); + } else if (isa<InvokeInst>(TI)) { + if (Personality == EHPersonality::MSVC_CXX && CleanupPad) { + // Invokes within a cleanuppad for the MSVC++ personality never + // transfer control to their unwind edge: the personality will + // terminate the program. + removeUnwindEdge(BB); } } } + } +} - // Anything else is either a catch block or interesting cleanup code. - for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end(); - II != IE; ++II) { - Instruction *Inst = II; - if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst)) - continue; - // Unconditional branches fall through to this loop. - if (Inst == Branch) - continue; - // If this is a catch block, there is no cleanup code to be found. - if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) - return; - // If this a nested landing pad, it may contain an endcatch call. - if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) - return; - // Anything else makes this interesting cleanup code. - return createCleanupHandler(Actions, CleanupHandlerMap, BB); - } - - // Only unconditional branches in empty blocks should get this far. - assert(Branch && Branch->isUnconditional()); - if (BB == EndBB) - return; - BB = Branch->getSuccessor(0); +void WinEHPrepare::cleanupPreparedFunclets(Function &F) { + // Clean-up some of the mess we made by removing useles PHI nodes, trivial + // branches, etc. + for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE;) { + BasicBlock *BB = &*FI++; + SimplifyInstructionsInBlock(BB); + ConstantFoldTerminator(BB, /*DeleteDeadConditions=*/true); + MergeBlockIntoPredecessor(BB); } + + // We might have some unreachable blocks after cleaning up some impossible + // control flow. + removeUnreachableBlocks(F); } -// This is a public function, declared in WinEHFuncInfo.h and is also -// referenced by WinEHNumbering in FunctionLoweringInfo.cpp. -void llvm::parseEHActions( - const IntrinsicInst *II, - SmallVectorImpl<std::unique_ptr<ActionHandler>> &Actions) { - assert(II->getIntrinsicID() == Intrinsic::eh_actions && - "attempted to parse non eh.actions intrinsic"); - for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) { - uint64_t ActionKind = - cast<ConstantInt>(II->getArgOperand(I))->getZExtValue(); - if (ActionKind == /*catch=*/1) { - auto *Selector = cast<Constant>(II->getArgOperand(I + 1)); - ConstantInt *EHObjIndex = cast<ConstantInt>(II->getArgOperand(I + 2)); - int64_t EHObjIndexVal = EHObjIndex->getSExtValue(); - Constant *Handler = cast<Constant>(II->getArgOperand(I + 3)); - I += 4; - auto CH = make_unique<CatchHandler>(/*BB=*/nullptr, Selector, - /*NextBB=*/nullptr); - CH->setHandlerBlockOrFunc(Handler); - CH->setExceptionVarIndex(EHObjIndexVal); - Actions.push_back(std::move(CH)); - } else if (ActionKind == 0) { - Constant *Handler = cast<Constant>(II->getArgOperand(I + 1)); - I += 2; - auto CH = make_unique<CleanupHandler>(/*BB=*/nullptr); - CH->setHandlerBlockOrFunc(Handler); - Actions.push_back(std::move(CH)); - } else { - llvm_unreachable("Expected either a catch or cleanup handler!"); +void WinEHPrepare::verifyPreparedFunclets(Function &F) { + // Recolor the CFG to verify that all is well. + for (BasicBlock &BB : F) { + size_t NumColors = BlockColors[&BB].size(); + assert(NumColors == 1 && "Expected monochromatic BB!"); + if (NumColors == 0) + report_fatal_error("Uncolored BB!"); + if (NumColors > 1) + report_fatal_error("Multicolor BB!"); + if (!DisableDemotion) { + 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!"); } } - std::reverse(Actions.begin(), Actions.end()); } -namespace { -struct WinEHNumbering { - WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo), - CurrentBaseState(-1), NextState(0) {} +bool WinEHPrepare::prepareExplicitEH(Function &F) { + // Remove unreachable blocks. It is not valuable to assign them a color and + // their existence can trick us into thinking values are alive when they are + // not. + removeUnreachableBlocks(F); - WinEHFuncInfo &FuncInfo; - int CurrentBaseState; - int NextState; + // Determine which blocks are reachable from which funclet entries. + colorFunclets(F); - SmallVector<std::unique_ptr<ActionHandler>, 4> HandlerStack; - SmallPtrSet<const Function *, 4> VisitedHandlers; + cloneCommonBlocks(F); - int currentEHNumber() const { - return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState(); - } + if (!DisableDemotion) + demotePHIsOnFunclets(F); - void createUnwindMapEntry(int ToState, ActionHandler *AH); - void createTryBlockMapEntry(int TryLow, int TryHigh, - ArrayRef<CatchHandler *> Handlers); - void processCallSite(MutableArrayRef<std::unique_ptr<ActionHandler>> Actions, - ImmutableCallSite CS); - void popUnmatchedActions(int FirstMismatch); - void calculateStateNumbers(const Function &F); - void findActionRootLPads(const Function &F); -}; -} + if (!DisableCleanups) { + removeImplausibleInstructions(F); -void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) { - WinEHUnwindMapEntry UME; - UME.ToState = ToState; - if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH)) - UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc()); - else - UME.Cleanup = nullptr; - FuncInfo.UnwindMap.push_back(UME); -} - -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(); - auto I = FuncInfo.TryBlockMap.begin(); - auto E = FuncInfo.TryBlockMap.end(); - for ( ; I != E; ++I) { - auto &Entry = *I; - if (Entry.HandlerArray.size() != (size_t)NumHandlers) - continue; - int N; - for (N = 0; N < NumHandlers; ++N) { - if (Entry.HandlerArray[N].Handler != Handlers[N]->getHandlerBlockOrFunc()) - break; // breaks out of inner loop - } - // If all the handlers match, this is what we were looking for. - if (N == NumHandlers) { - break; - } - } - - // If we found an existing entry for this set of handlers, extend the range - // but move the entry to the end of the map vector. The order of entries - // in the map is critical to the way that the runtime finds handlers. - // FIXME: Depending on what has happened with block ordering, this may - // incorrectly combine entries that should remain separate. - if (I != E) { - // Copy the existing entry. - WinEHTryBlockMapEntry Entry = *I; - Entry.TryLow = std::min(TryLow, Entry.TryLow); - Entry.TryHigh = std::max(TryHigh, Entry.TryHigh); - assert(Entry.TryLow <= Entry.TryHigh); - // Erase the old entry and add this one to the back. - FuncInfo.TryBlockMap.erase(I); - FuncInfo.TryBlockMap.push_back(Entry); - return; + cleanupPreparedFunclets(F); } - // If we didn't find an entry, create a new one. - WinEHTryBlockMapEntry TBME; - TBME.TryLow = TryLow; - TBME.TryHigh = TryHigh; - assert(TBME.TryLow <= TBME.TryHigh); - for (CatchHandler *CH : Handlers) { - WinEHHandlerType HT; - if (CH->getSelector()->isNullValue()) { - HT.Adjectives = 0x40; - HT.TypeDescriptor = nullptr; - } else { - auto *GV = cast<GlobalVariable>(CH->getSelector()->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 = cast<Function>(CH->getHandlerBlockOrFunc()); - HT.CatchObjRecoverIdx = CH->getExceptionVarIndex(); - TBME.HandlerArray.push_back(HT); - } - FuncInfo.TryBlockMap.push_back(TBME); -} + verifyPreparedFunclets(F); -static void print_name(const Value *V) { -#ifndef NDEBUG - if (!V) { - DEBUG(dbgs() << "null"); - return; - } + BlockColors.clear(); + FuncletBlocks.clear(); - if (const auto *F = dyn_cast<Function>(V)) - DEBUG(dbgs() << F->getName()); - else - DEBUG(V->dump()); -#endif + return true; } -void WinEHNumbering::processCallSite( - MutableArrayRef<std::unique_ptr<ActionHandler>> Actions, - ImmutableCallSite CS) { - DEBUG(dbgs() << "processCallSite (EH state = " << currentEHNumber() - << ") for: "); - print_name(CS ? CS.getCalledValue() : nullptr); - DEBUG(dbgs() << '\n'); - - DEBUG(dbgs() << "HandlerStack: \n"); - for (int I = 0, E = HandlerStack.size(); I < E; ++I) { - DEBUG(dbgs() << " "); - print_name(HandlerStack[I]->getHandlerBlockOrFunc()); - DEBUG(dbgs() << '\n'); - } - DEBUG(dbgs() << "Actions: \n"); - for (int I = 0, E = Actions.size(); I < E; ++I) { - DEBUG(dbgs() << " "); - print_name(Actions[I]->getHandlerBlockOrFunc()); - DEBUG(dbgs() << '\n'); - } - int FirstMismatch = 0; - for (int E = std::min(HandlerStack.size(), Actions.size()); FirstMismatch < E; - ++FirstMismatch) { - if (HandlerStack[FirstMismatch]->getHandlerBlockOrFunc() != - Actions[FirstMismatch]->getHandlerBlockOrFunc()) - break; - } - - // Remove unmatched actions from the stack and process their EH states. - popUnmatchedActions(FirstMismatch); - - DEBUG(dbgs() << "Pushing actions for CallSite: "); - print_name(CS ? CS.getCalledValue() : nullptr); - DEBUG(dbgs() << '\n'); - - bool LastActionWasCatch = false; - const LandingPadInst *LastRootLPad = nullptr; - for (size_t I = FirstMismatch; I != Actions.size(); ++I) { - // We can reuse eh states when pushing two catches for the same invoke. - bool CurrActionIsCatch = isa<CatchHandler>(Actions[I].get()); - auto *Handler = cast<Function>(Actions[I]->getHandlerBlockOrFunc()); - // Various conditions can lead to a handler being popped from the - // stack and re-pushed later. That shouldn't create a new state. - // FIXME: Can code optimization lead to re-used handlers? - if (FuncInfo.HandlerEnclosedState.count(Handler)) { - // If we already assigned the state enclosed by this handler re-use it. - Actions[I]->setEHState(FuncInfo.HandlerEnclosedState[Handler]); +// 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; + Instruction *EHPad = PHIBlock->getFirstNonPHI(); + + if (!isa<TerminatorInst>(EHPad)) { + // If the EHPad isn't a terminator, then we can insert a load in this block + // that will dominate all uses. + SpillSlot = new AllocaInst(PN->getType(), nullptr, + Twine(PN->getName(), ".wineh.spillslot"), + &F.getEntryBlock().front()); + Value *V = new LoadInst(SpillSlot, Twine(PN->getName(), ".wineh.reload"), + &*PHIBlock->getFirstInsertionPt()); + PN->replaceAllUsesWith(V); + return SpillSlot; + } + + // Otherwise, we have a PHI on a terminator EHPad, and we give up and insert + // loads of the slot before every use. + DenseMap<BasicBlock *, Value *> Loads; + for (Value::use_iterator UI = PN->use_begin(), UE = PN->use_end(); + UI != UE;) { + Use &U = *UI++; + auto *UsingInst = cast<Instruction>(U.getUser()); + if (isa<PHINode>(UsingInst) && UsingInst->getParent()->isEHPad()) { + // Use is on an EH pad phi. Leave it alone; we'll insert loads and + // stores for it separately. continue; } - const LandingPadInst* RootLPad = FuncInfo.RootLPad[Handler]; - if (CurrActionIsCatch && LastActionWasCatch && RootLPad == LastRootLPad) { - DEBUG(dbgs() << "setEHState for handler to " << currentEHNumber() << "\n"); - Actions[I]->setEHState(currentEHNumber()); - } else { - DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() << ", "); - print_name(Actions[I]->getHandlerBlockOrFunc()); - DEBUG(dbgs() << ") with EH state " << NextState << "\n"); - createUnwindMapEntry(currentEHNumber(), Actions[I].get()); - DEBUG(dbgs() << "setEHState for handler to " << NextState << "\n"); - Actions[I]->setEHState(NextState); - NextState++; - } - HandlerStack.push_back(std::move(Actions[I])); - LastActionWasCatch = CurrActionIsCatch; - LastRootLPad = RootLPad; + replaceUseWithLoad(PN, U, SpillSlot, Loads, F); } - - // This is used to defer numbering states for a handler until after the - // last time it appears in an invoke action list. - if (CS.isInvoke()) { - for (int I = 0, E = HandlerStack.size(); I < E; ++I) { - auto *Handler = cast<Function>(HandlerStack[I]->getHandlerBlockOrFunc()); - if (FuncInfo.LastInvoke[Handler] != cast<InvokeInst>(CS.getInstruction())) - continue; - FuncInfo.LastInvokeVisited[Handler] = true; - DEBUG(dbgs() << "Last invoke of "); - print_name(Handler); - DEBUG(dbgs() << " has been visited.\n"); - } - } - - DEBUG(dbgs() << "In EHState " << currentEHNumber() << " for CallSite: "); - print_name(CS ? CS.getCalledValue() : nullptr); - DEBUG(dbgs() << '\n'); + return SpillSlot; } -void WinEHNumbering::popUnmatchedActions(int FirstMismatch) { - // Don't recurse while we are looping over the handler stack. Instead, defer - // the numbering of the catch handlers until we are done popping. - SmallVector<CatchHandler *, 4> PoppedCatches; - for (int I = HandlerStack.size() - 1; I >= FirstMismatch; --I) { - std::unique_ptr<ActionHandler> Handler = HandlerStack.pop_back_val(); - if (isa<CatchHandler>(Handler.get())) - PoppedCatches.push_back(cast<CatchHandler>(Handler.release())); - } +// TODO: improve store placement. Inserting at def is probably good, but need +// to be careful not to introduce interfering stores (needs liveness analysis). +// TODO: identify related phi nodes that can share spill slots, and share them +// (also needs liveness). +void WinEHPrepare::insertPHIStores(PHINode *OriginalPHI, + AllocaInst *SpillSlot) { + // Use a worklist of (Block, Value) pairs -- the given Value needs to be + // stored to the spill slot by the end of the given Block. + SmallVector<std::pair<BasicBlock *, Value *>, 4> Worklist; - int TryHigh = NextState - 1; - int LastTryLowIdx = 0; - for (int I = 0, E = PoppedCatches.size(); I != E; ++I) { - CatchHandler *CH = PoppedCatches[I]; - DEBUG(dbgs() << "Popped handler with state " << CH->getEHState() << "\n"); - if (I + 1 == E || CH->getEHState() != PoppedCatches[I + 1]->getEHState()) { - int TryLow = CH->getEHState(); - auto Handlers = - makeArrayRef(&PoppedCatches[LastTryLowIdx], I - LastTryLowIdx + 1); - DEBUG(dbgs() << "createTryBlockMapEntry(" << TryLow << ", " << TryHigh); - for (size_t J = 0; J < Handlers.size(); ++J) { - DEBUG(dbgs() << ", "); - print_name(Handlers[J]->getHandlerBlockOrFunc()); - } - DEBUG(dbgs() << ")\n"); - createTryBlockMapEntry(TryLow, TryHigh, Handlers); - LastTryLowIdx = I + 1; - } - } + Worklist.push_back({OriginalPHI->getParent(), OriginalPHI}); - for (CatchHandler *CH : PoppedCatches) { - if (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc())) { - if (FuncInfo.LastInvokeVisited[F]) { - DEBUG(dbgs() << "Assigning base state " << NextState << " to "); - print_name(F); - DEBUG(dbgs() << '\n'); - FuncInfo.HandlerBaseState[F] = NextState; - DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() - << ", null)\n"); - createUnwindMapEntry(currentEHNumber(), nullptr); - ++NextState; - calculateStateNumbers(*F); + while (!Worklist.empty()) { + BasicBlock *EHBlock; + Value *InVal; + std::tie(EHBlock, InVal) = Worklist.pop_back_val(); + + PHINode *PN = dyn_cast<PHINode>(InVal); + if (PN && PN->getParent() == EHBlock) { + // The value is defined by another PHI we need to remove, with no room to + // insert a store after the PHI, so each predecessor needs to store its + // incoming value. + for (unsigned i = 0, e = PN->getNumIncomingValues(); i < e; ++i) { + Value *PredVal = PN->getIncomingValue(i); + + // Undef can safely be skipped. + if (isa<UndefValue>(PredVal)) + continue; + + insertPHIStore(PN->getIncomingBlock(i), PredVal, SpillSlot, Worklist); } - else { - DEBUG(dbgs() << "Deferring handling of "); - print_name(F); - DEBUG(dbgs() << " until last invoke visited.\n"); + } else { + // We need to store InVal, which dominates EHBlock, but can't put a store + // in EHBlock, so need to put stores in each predecessor. + for (BasicBlock *PredBlock : predecessors(EHBlock)) { + insertPHIStore(PredBlock, InVal, SpillSlot, Worklist); } } - delete CH; } } -void WinEHNumbering::calculateStateNumbers(const Function &F) { - auto I = VisitedHandlers.insert(&F); - if (!I.second) - return; // We've already visited this handler, don't renumber it. +void WinEHPrepare::insertPHIStore( + BasicBlock *PredBlock, Value *PredVal, AllocaInst *SpillSlot, + SmallVectorImpl<std::pair<BasicBlock *, Value *>> &Worklist) { - int OldBaseState = CurrentBaseState; - if (FuncInfo.HandlerBaseState.count(&F)) { - CurrentBaseState = FuncInfo.HandlerBaseState[&F]; - } - - size_t SavedHandlerStackSize = HandlerStack.size(); - - DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n'); - SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList; - for (const BasicBlock &BB : F) { - for (const Instruction &I : BB) { - const auto *CI = dyn_cast<CallInst>(&I); - if (!CI || CI->doesNotThrow()) - continue; - processCallSite(None, CI); - } - const auto *II = dyn_cast<InvokeInst>(BB.getTerminator()); - if (!II) - continue; - const LandingPadInst *LPI = II->getLandingPadInst(); - 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(); - DEBUG(dbgs() << "Assigning state " << currentEHNumber() - << " to landing pad at " << LPI->getParent()->getName() - << '\n'); + if (PredBlock->isEHPad() && + isa<TerminatorInst>(PredBlock->getFirstNonPHI())) { + // Pred is unsplittable, so we need to queue it on the worklist. + Worklist.push_back({PredBlock, PredVal}); + return; } - // Pop any actions that were pushed on the stack for this function. - popUnmatchedActions(SavedHandlerStackSize); - - DEBUG(dbgs() << "Assigning max state " << NextState - 1 - << " to " << F.getName() << '\n'); - FuncInfo.CatchHandlerMaxState[&F] = NextState - 1; - - CurrentBaseState = OldBaseState; + // Otherwise, insert the store at the end of the basic block. + new StoreInst(PredVal, SpillSlot, PredBlock->getTerminator()); } -// This function follows the same basic traversal as calculateStateNumbers -// but it is necessary to identify the root landing pad associated -// with each action before we start assigning state numbers. -void WinEHNumbering::findActionRootLPads(const Function &F) { - auto I = VisitedHandlers.insert(&F); - if (!I.second) - return; // We've already visited this handler, don't revisit it. - - SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList; - for (const BasicBlock &BB : F) { - const auto *II = dyn_cast<InvokeInst>(BB.getTerminator()); - if (!II) - continue; - const LandingPadInst *LPI = II->getLandingPadInst(); - auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode()); - if (!ActionsCall) - continue; - - assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions); - parseEHActions(ActionsCall, ActionList); - if (ActionList.empty()) - continue; - for (int I = 0, E = ActionList.size(); I < E; ++I) { - if (auto *Handler - = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc())) { - FuncInfo.LastInvoke[Handler] = II; - // Don't replace the root landing pad if we previously saw this - // handler in a different function. - if (FuncInfo.RootLPad.count(Handler) && - FuncInfo.RootLPad[Handler]->getParent()->getParent() != &F) - continue; - DEBUG(dbgs() << "Setting root lpad for "); - print_name(Handler); - DEBUG(dbgs() << " to " << LPI->getParent()->getName() << '\n'); - FuncInfo.RootLPad[Handler] = LPI; - } +void WinEHPrepare::replaceUseWithLoad(Value *V, Use &U, AllocaInst *&SpillSlot, + DenseMap<BasicBlock *, Value *> &Loads, + Function &F) { + // Lazilly create the spill slot. + if (!SpillSlot) + SpillSlot = new AllocaInst(V->getType(), nullptr, + Twine(V->getName(), ".wineh.spillslot"), + &F.getEntryBlock().front()); + + auto *UsingInst = cast<Instruction>(U.getUser()); + if (auto *UsingPHI = dyn_cast<PHINode>(UsingInst)) { + // If this is a PHI node, we can't insert a load of the value before + // the use. Instead insert the load in the predecessor block + // corresponding to the incoming value. + // + // Note that if there are multiple edges from a basic block to this + // PHI node that we cannot have multiple loads. The problem is that + // the resulting PHI node will have multiple values (from each load) + // coming in from the same block, which is illegal SSA form. + // For this reason, we keep track of and reuse loads we insert. + BasicBlock *IncomingBlock = UsingPHI->getIncomingBlock(U); + if (auto *CatchRet = + dyn_cast<CatchReturnInst>(IncomingBlock->getTerminator())) { + // Putting a load above a catchret and use on the phi would still leave + // a cross-funclet def/use. We need to split the edge, change the + // catchret to target the new block, and put the load there. + BasicBlock *PHIBlock = UsingInst->getParent(); + BasicBlock *NewBlock = SplitEdge(IncomingBlock, PHIBlock); + // SplitEdge gives us: + // IncomingBlock: + // ... + // br label %NewBlock + // NewBlock: + // catchret label %PHIBlock + // But we need: + // IncomingBlock: + // ... + // catchret label %NewBlock + // NewBlock: + // br label %PHIBlock + // So move the terminators to each others' blocks and swap their + // successors. + BranchInst *Goto = cast<BranchInst>(IncomingBlock->getTerminator()); + Goto->removeFromParent(); + CatchRet->removeFromParent(); + IncomingBlock->getInstList().push_back(CatchRet); + NewBlock->getInstList().push_back(Goto); + Goto->setSuccessor(0, PHIBlock); + CatchRet->setSuccessor(NewBlock); + // Update the color mapping for the newly split edge. + ColorVector &ColorsForPHIBlock = BlockColors[PHIBlock]; + BlockColors[NewBlock] = ColorsForPHIBlock; + for (BasicBlock *FuncletPad : ColorsForPHIBlock) + FuncletBlocks[FuncletPad].push_back(NewBlock); + // Treat the new block as incoming for load insertion. + IncomingBlock = NewBlock; } - // Walk the actions again and look for nested handlers. This has to - // happen after all of the actions have been processed in the current - // function. - for (int I = 0, E = ActionList.size(); I < E; ++I) - if (auto *Handler - = dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc())) - findActionRootLPads(*Handler); - ActionList.clear(); + Value *&Load = Loads[IncomingBlock]; + // Insert the load into the predecessor block + if (!Load) + Load = new LoadInst(SpillSlot, Twine(V->getName(), ".wineh.reload"), + /*Volatile=*/false, IncomingBlock->getTerminator()); + + U.set(Load); + } else { + // Reload right before the old use. + auto *Load = new LoadInst(SpillSlot, Twine(V->getName(), ".wineh.reload"), + /*Volatile=*/false, UsingInst); + U.set(Load); } } -void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn, - WinEHFuncInfo &FuncInfo) { - // Return if it's already been done. - if (!FuncInfo.LandingPadStateMap.empty()) - 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); - // Pop everything on the handler stack. - // It may be necessary to call this more than once because a handler can - // be pushed on the stack as a result of clearing the stack. - while (!Num.HandlerStack.empty()) - Num.processCallSite(None, ImmutableCallSite()); +void WinEHFuncInfo::addIPToStateRange(const InvokeInst *II, + MCSymbol *InvokeBegin, + MCSymbol *InvokeEnd) { + assert(InvokeStateMap.count(II) && + "should get invoke with precomputed state"); + LabelToStateMap[InvokeBegin] = std::make_pair(InvokeStateMap[II], InvokeEnd); } + +WinEHFuncInfo::WinEHFuncInfo() {} |
