| //===-- WinEHPrepare - Prepare exception handling for code generation ---===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This pass lowers LLVM IR exception handling into something closer to what the |
| // backend wants. It snifs the personality function to see which kind of |
| // preparation is necessary. If the personality function uses the Itanium LSDA, |
| // this pass delegates to the DWARF EH preparation pass. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/CodeGen/Passes.h" |
| #include "llvm/ADT/MapVector.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallSet.h" |
| #include "llvm/ADT/TinyPtrVector.h" |
| #include "llvm/Analysis/LibCallSemantics.h" |
| #include "llvm/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/Pass.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/Debug.h" |
| #include "llvm/Support/raw_ostream.h" |
| #include "llvm/Transforms/Utils/BasicBlockUtils.h" |
| #include "llvm/Transforms/Utils/Cloning.h" |
| #include "llvm/Transforms/Utils/Local.h" |
| #include "llvm/Transforms/Utils/PromoteMemToReg.h" |
| #include <memory> |
| |
| 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; |
| |
| class LandingPadActions; |
| class LandingPadMap; |
| |
| typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy; |
| typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy; |
| |
| class WinEHPrepare : public FunctionPass { |
| public: |
| static char ID; // Pass identification, replacement for typeid. |
| WinEHPrepare(const TargetMachine *TM = nullptr) |
| : FunctionPass(ID), DT(nullptr) {} |
| |
| bool runOnFunction(Function &Fn) override; |
| |
| bool doFinalization(Module &M) override; |
| |
| void getAnalysisUsage(AnalysisUsage &AU) const override; |
| |
| const char *getPassName() const override { |
| return "Windows exception handling preparation"; |
| } |
| |
| private: |
| bool prepareExceptionHandlers(Function &F, |
| SmallVectorImpl<LandingPadInst *> &LPads); |
| void promoteLandingPadValues(LandingPadInst *LPad); |
| void completeNestedLandingPad(Function *ParentFn, |
| LandingPadInst *OutlinedLPad, |
| const LandingPadInst *OriginalLPad, |
| FrameVarInfoMap &VarInfo); |
| bool outlineHandler(ActionHandler *Action, Function *SrcFn, |
| LandingPadInst *LPad, BasicBlock *StartBB, |
| FrameVarInfoMap &VarInfo); |
| void addStubInvokeToHandlerIfNeeded(Function *Handler, Value *PersonalityFn); |
| |
| 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); |
| |
| // All fields are reset by runOnFunction. |
| DominatorTree *DT; |
| EHPersonality Personality; |
| CatchHandlerMapTy CatchHandlerMap; |
| CleanupHandlerMapTy CleanupHandlerMap; |
| DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps; |
| |
| // 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; |
| }; |
| |
| class WinEHFrameVariableMaterializer : public ValueMaterializer { |
| public: |
| WinEHFrameVariableMaterializer(Function *OutlinedFn, |
| 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, FrameVarInfoMap &VarInfo, |
| LandingPadMap &LPadMap) |
| : Materializer(HandlerFn, VarInfo), |
| SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())), |
| Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())), |
| LPadMap(LPadMap) {} |
| |
| CloningAction handleInstruction(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| |
| virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) = 0; |
| virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) = 0; |
| virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) = 0; |
| virtual CloningAction handleInvoke(ValueToValueMapTy &VMap, |
| const InvokeInst *Invoke, |
| BasicBlock *NewBB) = 0; |
| virtual CloningAction handleResume(ValueToValueMapTy &VMap, |
| const ResumeInst *Resume, |
| BasicBlock *NewBB) = 0; |
| 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; |
| }; |
| |
| class WinEHCatchDirector : public WinEHCloningDirectorBase { |
| public: |
| WinEHCatchDirector( |
| Function *CatchFn, Value *Selector, FrameVarInfoMap &VarInfo, |
| LandingPadMap &LPadMap, |
| DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads) |
| : WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap), |
| CurrentSelector(Selector->stripPointerCasts()), |
| ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads) {} |
| |
| CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke, |
| BasicBlock *NewBB) override; |
| CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| BasicBlock *NewBB) override; |
| 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; |
| }; |
| |
| class WinEHCleanupDirector : public WinEHCloningDirectorBase { |
| public: |
| WinEHCleanupDirector(Function *CleanupFn, FrameVarInfoMap &VarInfo, |
| LandingPadMap &LPadMap) |
| : WinEHCloningDirectorBase(CleanupFn, VarInfo, LPadMap) {} |
| |
| CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| const Instruction *Inst, |
| BasicBlock *NewBB) override; |
| CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke, |
| BasicBlock *NewBB) override; |
| CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| BasicBlock *NewBB) override; |
| 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; |
| }; |
| |
| } // end anonymous namespace |
| |
| char WinEHPrepare::ID = 0; |
| INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions", |
| false, false) |
| |
| FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) { |
| return new WinEHPrepare(TM); |
| } |
| |
| // FIXME: Remove this once the backend can handle the prepared IR. |
| static cl::opt<bool> |
| SEHPrepare("sehprepare", cl::Hidden, |
| cl::desc("Prepare functions with SEH personalities")); |
| |
| bool WinEHPrepare::runOnFunction(Function &Fn) { |
| SmallVector<LandingPadInst *, 4> LPads; |
| 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()) |
| return false; |
| |
| // Classify the personality to see what kind of preparation we need. |
| Personality = classifyEHPersonality(LPads.back()->getPersonalityFn()); |
| |
| // Do nothing if this is not an MSVC personality. |
| if (!isMSVCEHPersonality(Personality)) |
| return false; |
| |
| DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree(); |
| |
| if (isAsynchronousEHPersonality(Personality) && !SEHPrepare) { |
| // Replace all resume instructions with unreachable. |
| // FIXME: Remove this once the backend can handle the prepared IR. |
| for (ResumeInst *Resume : Resumes) { |
| IRBuilder<>(Resume).CreateUnreachable(); |
| Resume->eraseFromParent(); |
| } |
| return true; |
| } |
| |
| // If there were any landing pads, prepareExceptionHandlers will make changes. |
| prepareExceptionHandlers(Fn, LPads); |
| return true; |
| } |
| |
| bool WinEHPrepare::doFinalization(Module &M) { return false; } |
| |
| void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const { |
| AU.addRequired<DominatorTreeWrapperPass>(); |
| } |
| |
| bool WinEHPrepare::prepareExceptionHandlers( |
| Function &F, SmallVectorImpl<LandingPadInst *> &LPads) { |
| // These containers are used to re-map frame variables that are used in |
| // outlined catch and cleanup handlers. They will be populated as the |
| // handlers are outlined. |
| FrameVarInfoMap FrameVarInfo; |
| |
| bool HandlersOutlined = false; |
| |
| Module *M = F.getParent(); |
| LLVMContext &Context = M->getContext(); |
| |
| // Create a new function to receive the handler contents. |
| PointerType *Int8PtrType = Type::getInt8PtrTy(Context); |
| Type *Int32Type = Type::getInt32Ty(Context); |
| Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions); |
| |
| for (LandingPadInst *LPad : LPads) { |
| // Look for evidence that this landingpad has already been processed. |
| bool LPadHasActionList = false; |
| BasicBlock *LPadBB = LPad->getParent(); |
| for (Instruction &Inst : *LPadBB) { |
| if (auto *IntrinCall = dyn_cast<IntrinsicInst>(&Inst)) { |
| if (IntrinCall->getIntrinsicID() == Intrinsic::eh_actions) { |
| LPadHasActionList = true; |
| break; |
| } |
| } |
| // FIXME: This is here to help with the development of nested landing pad |
| // outlining. It should be removed when that is finished. |
| if (isa<UnreachableInst>(Inst)) { |
| LPadHasActionList = true; |
| break; |
| } |
| } |
| |
| // If we've already outlined the handlers for this landingpad, |
| // 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); |
| } |
| |
| // Replace the landing pad with a new llvm.eh.action based landing pad. |
| BasicBlock *NewLPadBB = BasicBlock::Create(Context, "lpad", &F, LPadBB); |
| assert(!isa<PHINode>(LPadBB->begin())); |
| auto *NewLPad = cast<LandingPadInst>(LPad->clone()); |
| NewLPadBB->getInstList().push_back(NewLPad); |
| while (!pred_empty(LPadBB)) { |
| auto *pred = *pred_begin(LPadBB); |
| InvokeInst *Invoke = cast<InvokeInst>(pred->getTerminator()); |
| Invoke->setUnwindDest(NewLPadBB); |
| } |
| |
| // If anyone is still using the old landingpad value, just give them undef |
| // instead. The eh pointer and selector values are not real. |
| LPad->replaceAllUsesWith(UndefValue::get(LPad->getType())); |
| |
| // Replace the mapping of any nested landing pad that previously mapped |
| // to this landing pad with a referenced to the cloned version. |
| for (auto &LPadPair : NestedLPtoOriginalLP) { |
| const LandingPadInst *OriginalLPad = LPadPair.second; |
| if (OriginalLPad == LPad) { |
| LPadPair.second = NewLPad; |
| } |
| } |
| |
| // Replace uses of the old lpad in phis with this block and delete the old |
| // block. |
| LPadBB->replaceSuccessorsPhiUsesWith(NewLPadBB); |
| LPadBB->getTerminator()->eraseFromParent(); |
| new UnreachableInst(LPadBB->getContext(), LPadBB); |
| |
| // Add a call to describe the actions for this landing pad. |
| std::vector<Value *> ActionArgs; |
| for (ActionHandler *Action : Actions) { |
| // Action codes from docs are: 0 cleanup, 1 catch. |
| if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) { |
| ActionArgs.push_back(ConstantInt::get(Int32Type, 1)); |
| ActionArgs.push_back(CatchAction->getSelector()); |
| // 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", NewLPadBB); |
| |
| // Add an indirect branch listing possible successors of the catch handlers. |
| IndirectBrInst *Branch = IndirectBrInst::Create(Recover, 0, NewLPadBB); |
| for (ActionHandler *Action : Actions) { |
| if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) { |
| for (auto *Target : CatchAction->getReturnTargets()) { |
| Branch->addDestination(Target); |
| } |
| } |
| } |
| } // End for each landingpad |
| |
| // If nothing got outlined, there is no more processing to be done. |
| if (!HandlersOutlined) |
| return false; |
| |
| // 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(); |
| |
| F.addFnAttr("wineh-parent", F.getName()); |
| |
| // Delete any blocks that were only used by handlers that were outlined above. |
| removeUnreachableBlocks(F); |
| |
| BasicBlock *Entry = &F.getEntryBlock(); |
| IRBuilder<> Builder(F.getParent()->getContext()); |
| Builder.SetInsertPoint(Entry->getFirstInsertionPt()); |
| |
| Function *FrameEscapeFn = |
| Intrinsic::getDeclaration(M, Intrinsic::frameescape); |
| Function *RecoverFrameFn = |
| Intrinsic::getDeclaration(M, Intrinsic::framerecover); |
| |
| // Finally, replace all of the temporary allocas for frame variables used in |
| // the outlined handlers with calls to llvm.framerecover. |
| BasicBlock::iterator II = Entry->getFirstInsertionPt(); |
| Instruction *AllocaInsertPt = II; |
| SmallVector<Value *, 8> AllocasToEscape; |
| for (auto &VarInfoEntry : FrameVarInfo) { |
| Value *ParentVal = VarInfoEntry.first; |
| TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second; |
| |
| // If the mapped value isn't already an alloca, we need to spill it if it |
| // is a computed value or copy it if it is an argument. |
| AllocaInst *ParentAlloca = dyn_cast<AllocaInst>(ParentVal); |
| if (!ParentAlloca) { |
| if (auto *Arg = dyn_cast<Argument>(ParentVal)) { |
| // Lower this argument to a copy and then demote that to the stack. |
| // We can't just use the argument location because the handler needs |
| // it to be in the frame allocation block. |
| // Use 'select i8 true, %arg, undef' to simulate a 'no-op' instruction. |
| Value *TrueValue = ConstantInt::getTrue(Context); |
| Value *UndefValue = UndefValue::get(Arg->getType()); |
| Instruction *SI = |
| SelectInst::Create(TrueValue, Arg, UndefValue, |
| Arg->getName() + ".tmp", AllocaInsertPt); |
| Arg->replaceAllUsesWith(SI); |
| // Reset the select operand, because it was clobbered by the RAUW above. |
| SI->setOperand(1, Arg); |
| ParentAlloca = DemoteRegToStack(*SI, true, SI); |
| } else if (auto *PN = dyn_cast<PHINode>(ParentVal)) { |
| ParentAlloca = DemotePHIToStack(PN, AllocaInsertPt); |
| } else { |
| Instruction *ParentInst = cast<Instruction>(ParentVal); |
| // FIXME: This is a work-around to temporarily handle the case where an |
| // instruction that is only used in handlers is not sunk. |
| // Without uses, DemoteRegToStack would just eliminate the value. |
| // This will fail if ParentInst is an invoke. |
| if (ParentInst->getNumUses() == 0) { |
| BasicBlock::iterator InsertPt = ParentInst; |
| ++InsertPt; |
| ParentAlloca = |
| new AllocaInst(ParentInst->getType(), nullptr, |
| ParentInst->getName() + ".reg2mem", |
| AllocaInsertPt); |
| new StoreInst(ParentInst, ParentAlloca, InsertPt); |
| } else { |
| ParentAlloca = DemoteRegToStack(*ParentInst, true, AllocaInsertPt); |
| } |
| } |
| } |
| |
| // 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(); |
| // FIXME: Sink this GEP into the blocks where it is used. |
| Builder.SetInsertPoint(TempAlloca); |
| Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc()); |
| Value *RecoverArgs[] = { |
| Builder.CreateBitCast(&F, Int8PtrType, ""), |
| &(HandlerFn->getArgumentList().back()), |
| llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)}; |
| Value *RecoveredAlloca = Builder.CreateCall(RecoverFrameFn, RecoverArgs); |
| // Add a pointer bitcast if the alloca wasn't an i8. |
| if (RecoveredAlloca->getType() != TempAlloca->getType()) { |
| RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8"); |
| RecoveredAlloca = |
| Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType()); |
| } |
| TempAlloca->replaceAllUsesWith(RecoveredAlloca); |
| TempAlloca->removeFromParent(); |
| RecoveredAlloca->takeName(TempAlloca); |
| delete TempAlloca; |
| } |
| } // End for each FrameVarInfo entry. |
| |
| // Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry |
| // block. |
| Builder.SetInsertPoint(&F.getEntryBlock().back()); |
| Builder.CreateCall(FrameEscapeFn, AllocasToEscape); |
| |
| // Clean up the handler action maps we created for this function |
| DeleteContainerSeconds(CatchHandlerMap); |
| CatchHandlerMap.clear(); |
| DeleteContainerSeconds(CleanupHandlerMap); |
| CleanupHandlerMap.clear(); |
| |
| return HandlersOutlined; |
| } |
| |
| 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; |
| |
| for (auto *EU : Extract->users()) { |
| if (auto *Store = dyn_cast<StoreInst>(EU)) { |
| auto *AV = cast<AllocaInst>(Store->getPointerOperand()); |
| EHAllocas.push_back(AV); |
| } |
| } |
| } |
| |
| // We can't do this without a dominator tree. |
| assert(DT); |
| |
| if (!EHAllocas.empty()) { |
| PromoteMemToReg(EHAllocas, *DT); |
| EHAllocas.clear(); |
| } |
| |
| // 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); |
| } |
| |
| 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(); |
| assert(isa<UnreachableInst>(OutlinedBB->getTerminator())); |
| OutlinedBB->getTerminator()->eraseFromParent(); |
| // That should leave OutlinedLPad as the last instruction in its block. |
| assert(&OutlinedBB->back() == OutlinedLPad); |
| |
| // 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; |
| assert(match(Recover, m_Intrinsic<Intrinsic::eh_actions>())); |
| IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover->clone()); |
| |
| // Remap the exception variables into the outlined function. |
| WinEHFrameVariableMaterializer Materializer(OutlinedHandlerFn, FrameVarInfo); |
| SmallVector<BlockAddress *, 4> ActionTargets; |
| SmallVector<ActionHandler *, 4> ActionList; |
| parseEHActions(EHActions, ActionList); |
| for (auto *Action : ActionList) { |
| auto *Catch = dyn_cast<CatchHandler>(Action); |
| if (!Catch) |
| 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) |
| 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 OutlinedHandlerFn. |
| 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); |
| } |
| } |
| DeleteContainerPointers(ActionList); |
| ActionList.clear(); |
| OutlinedBB->getInstList().push_back(EHActions); |
| |
| // Insert an indirect branch into the outlined landing pad BB. |
| IndirectBrInst *IBr = IndirectBrInst::Create(EHActions, 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; |
| } |
| |
| return false; |
| } |
| |
| static BasicBlock *createStubLandingPad(Function *Handler, |
| Value *PersonalityFn) { |
| // 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), |
| PersonalityFn, 0); |
| 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, |
| Value *PersonalityFn) { |
| ReturnInst *Ret = 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) |
| continue; |
| // If we haven't recorded a return instruction yet, try this terminator. |
| Ret = dyn_cast<ReturnInst>(Terminator); |
| } |
| |
| // If we got this far, the handler contains no invokes. We should have seen |
| // at least one return. We'll insert an invoke of llvm.donothing ahead of |
| // that return. |
| assert(Ret); |
| BasicBlock *OldRetBB = Ret->getParent(); |
| BasicBlock *NewRetBB = SplitBlock(OldRetBB, Ret); |
| // 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, PersonalityFn); |
| Function *F = |
| Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing); |
| InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB); |
| } |
| |
| bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn, |
| LandingPadInst *LPad, BasicBlock *StartBB, |
| FrameVarInfoMap &VarInfo) { |
| Module *M = SrcFn->getParent(); |
| LLVMContext &Context = M->getContext(); |
| |
| // Create a new function to receive the handler contents. |
| Type *Int8PtrType = Type::getInt8PtrTy(Context); |
| std::vector<Type *> ArgTys; |
| ArgTys.push_back(Int8PtrType); |
| ArgTys.push_back(Int8PtrType); |
| Function *Handler; |
| if (Action->getType() == Catch) { |
| FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false); |
| Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| SrcFn->getName() + ".catch", M); |
| } else { |
| FunctionType *FnType = |
| FunctionType::get(Type::getVoidTy(Context), ArgTys, false); |
| Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| SrcFn->getName() + ".cleanup", M); |
| } |
| |
| Handler->addFnAttr("wineh-parent", SrcFn->getName()); |
| |
| // Generate a standard prolog to setup the frame recovery structure. |
| IRBuilder<> Builder(Context); |
| BasicBlock *Entry = BasicBlock::Create(Context, "entry"); |
| Handler->getBasicBlockList().push_front(Entry); |
| 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, Sel, VarInfo, LPadMap, |
| NestedLPtoOriginalLP)); |
| LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType), |
| ConstantInt::get(Type::getInt32Ty(Context), 1)); |
| } else { |
| Director.reset(new WinEHCleanupDirector(Handler, VarInfo, LPadMap)); |
| LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType), |
| UndefValue::get(Type::getInt32Ty(Context))); |
| } |
| |
| 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; |
| } |
| |
| // 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 first cloned block into our entry block. |
| BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry)); |
| Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList()); |
| FirstClonedBB->eraseFromParent(); |
| |
| // Make sure we can identify the handler's personality later. |
| addStubInvokeToHandlerIfNeeded(Handler, LPad->getPersonalityFn()); |
| |
| 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) |
| 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); |
| } |
| } |
| } |
| } // 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 = |
| StartBB->splitBasicBlock(StartBB->getFirstInsertionPt(), "catch.all"); |
| } |
| 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); |
| } |
| } |
| } |
| |
| bool LandingPadMap::isOriginLandingPadBlock(const BasicBlock *BB) const { |
| return BB->getLandingPadInst() == OriginLPad; |
| } |
| |
| 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; |
| } |
| |
| 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 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); |
| } |
| |
| if (auto *Invoke = dyn_cast<InvokeInst>(Inst)) |
| return handleInvoke(VMap, Invoke, NewBB); |
| |
| if (auto *Resume = dyn_cast<ResumeInst>(Inst)) |
| return handleResume(VMap, Resume, NewBB); |
| |
| if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) |
| return handleBeginCatch(VMap, Inst, NewBB); |
| if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) |
| return handleEndCatch(VMap, Inst, NewBB); |
| if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) |
| return handleTypeIdFor(VMap, Inst, NewBB); |
| |
| // Continue with the default cloning behavior. |
| return CloningDirector::CloneInstruction; |
| } |
| |
| CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad( |
| ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) { |
| 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); |
| } |
| |
| 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::handleInvoke(ValueToValueMapTy &VMap, |
| const InvokeInst *Invoke, BasicBlock *NewBB) { |
| return CloningDirector::CloneInstruction; |
| } |
| |
| CloningDirector::CloningAction |
| WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap, |
| const ResumeInst *Resume, BasicBlock *NewBB) { |
| // Resume instructions shouldn't be reachable from catch handlers. |
| // We still need to handle it, but it will be pruned. |
| BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| return CloningDirector::StopCloningBB; |
| } |
| |
| CloningDirector::CloningAction WinEHCleanupDirector::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) { |
| // Catch blocks within cleanup handlers will always be unreachable. |
| // We'll insert an unreachable instruction now, but it will be pruned |
| // before the cloning process is complete. |
| BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| return CloningDirector::StopCloningBB; |
| } |
| |
| CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch( |
| ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| // 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::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; |
| } |
| |
| WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer( |
| Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo) |
| : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) { |
| BasicBlock *EntryBB = &OutlinedFn->getEntryBlock(); |
| Builder.SetInsertPoint(EntryBB, EntryBB->getFirstInsertionPt()); |
| } |
| |
| Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) { |
| // If we're asked to materialize a value that is an instruction, we |
| // temporarily create an alloca in the outlined function and add this |
| // to the FrameVarInfo map. When all the outlining is complete, we'll |
| // collect these into a structure, spilling non-alloca values in the |
| // parent frame as necessary, and replace these temporary allocas with |
| // GEPs referencing the frame allocation block. |
| |
| // If the value is an alloca, the mapping is direct. |
| if (auto *AV = dyn_cast<AllocaInst>(V)) { |
| AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone()); |
| Builder.Insert(NewAlloca, AV->getName()); |
| FrameVarInfo[AV].push_back(NewAlloca); |
| return NewAlloca; |
| } |
| |
| // For other types of instructions or arguments, we need an alloca based on |
| // the value's type and a load of the alloca. The alloca will be replaced |
| // by a GEP, but the load will stay. In the parent function, the value will |
| // be spilled to a location in the frame allocation block. |
| if (isa<Instruction>(V) || isa<Argument>(V)) { |
| AllocaInst *NewAlloca = |
| Builder.CreateAlloca(V->getType(), nullptr, "eh.temp.alloca"); |
| FrameVarInfo[V].push_back(NewAlloca); |
| LoadInst *NewLoad = Builder.CreateLoad(NewAlloca, V->getName() + ".reload"); |
| return NewLoad; |
| } |
| |
| // Don't materialize other values. |
| return nullptr; |
| } |
| |
| 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.frameescape. |
| FrameVarInfo[V].push_back(getCatchObjectSentinel()); |
| } |
| |
| // 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; |
| } |
| |
| VisitedBlockSet VisitedBlocks; |
| |
| while (HandlersFound != NumClauses) { |
| BasicBlock *NextBB = nullptr; |
| |
| // See if the clause we're looking for is a catch-all. |
| // If so, the catch begins immediately. |
| if (isa<ConstantPointerNull>(LPad->getClause(HandlersFound))) { |
| // The catch all must occur last. |
| assert(HandlersFound == NumClauses - 1); |
| |
| // For C++ EH, check if there is any interesting cleanup code before we |
| // begin the catch. This is important because cleanups cannot rethrow |
| // exceptions but code called from catches can. For SEH, it isn't |
| // important if some finally code before a catch-all is executed out of |
| // line or after recovering from the exception. |
| if (Personality == EHPersonality::MSVC_CXX) |
| findCleanupHandlers(Actions, BB, BB); |
| |
| // Add the catch handler to the action list. |
| CatchHandler *Action = |
| new CatchHandler(BB, LPad->getClause(HandlersFound), nullptr); |
| CatchHandlerMap[BB] = Action; |
| Actions.insertCatchHandler(Action); |
| DEBUG(dbgs() << " Catch all handler at block " << BB->getName() << "\n"); |
| ++HandlersFound; |
| |
| // Once we reach a catch-all, don't expect to hit a resume instruction. |
| BB = nullptr; |
| break; |
| } |
| |
| CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks); |
| // See if there is any interesting code executed before the dispatch. |
| findCleanupHandlers(Actions, BB, CatchAction->getStartBlock()); |
| |
| assert(CatchAction); |
| ++HandlersFound; |
| |
| // Add the catch handler to the action list. |
| Actions.insertCatchHandler(CatchAction); |
| DEBUG(dbgs() << " Found catch dispatch in block " |
| << CatchAction->getStartBlock()->getName() << "\n"); |
| |
| // Move on to the block after the catch handler. |
| BB = NextBB; |
| } |
| |
| // If we didn't wind up in a catch-all, see if there is any interesting code |
| // executed before the resume. |
| 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; |
| } |
| |
| // VisitedBlocks applies only to the current search. We still |
| // need to consider blocks that we've visited while mapping other |
| // landing pads. |
| VisitedBlocks.insert(BB); |
| |
| BasicBlock *CatchBlock = nullptr; |
| Constant *Selector = nullptr; |
| |
| // If this is the first time we've visited this block from any landing pad |
| // look to see if it is a selector dispatch block. |
| if (!CatchHandlerMap.count(BB)) { |
| if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) { |
| CatchHandler *Action = new CatchHandler(BB, Selector, NextBB); |
| CatchHandlerMap[BB] = Action; |
| return Action; |
| } |
| } |
| |
| // Visit each successor, looking for the dispatch. |
| // FIXME: We expect to find the dispatch quickly, so this will probably |
| // work better as a breadth first search. |
| for (BasicBlock *Succ : successors(BB)) { |
| if (VisitedBlocks.count(Succ)) |
| continue; |
| |
| CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks); |
| if (Action) |
| return Action; |
| } |
| return nullptr; |
| } |
| |
| // These are helper functions to combine repeated code from 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 bool isFrameAddressCall(Value *V) { |
| return match(V, m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0))); |
| } |
| |
| static CallSite matchOutlinedFinallyCall(BasicBlock *BB, |
| Instruction *MaybeCall) { |
| // Look for finally blocks that Clang has already outlined for us. |
| // %fp = call i8* @llvm.frameaddress(i32 0) |
| // call void @"fin$parent"(iN 1, i8* %fp) |
| if (isFrameAddressCall(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 (!isFrameAddressCall(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 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; |
| continue; |
| } |
| } |
| |
| // Create an entry in the cleanup handler map for this block. Initially |
| // we create an entry that says this isn't a cleanup block. If we find |
| // cleanup code, the caller will replace this entry. |
| CleanupHandlerMap[BB] = nullptr; |
| |
| TerminatorInst *Terminator = BB->getTerminator(); |
| |
| // Landing pad blocks have extra instructions we need to accept. |
| LandingPadMap *LPadMap = nullptr; |
| if (BB->isLandingPad()) { |
| LandingPadInst *LPad = BB->getLandingPadInst(); |
| LPadMap = &LPadMaps[LPad]; |
| if (!LPadMap->isInitialized()) |
| LPadMap->mapLandingPad(LPad); |
| } |
| |
| // Look for the bare resume pattern: |
| // %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) |
| 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) |
| continue; |
| if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) |
| 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(); |
| } |
| |
| // Look for outlined finally calls. |
| 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 = BB->splitBasicBlock(FinallyCall.getInstruction()->getNextNode()); |
| } 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; |
| } |
| } |
| |
| // 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); |
| } |
| } |
| |
| // 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<ActionHandler *> &Actions) { |
| 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 = new CatchHandler(/*BB=*/nullptr, Selector, /*NextBB=*/nullptr); |
| CH->setHandlerBlockOrFunc(Handler); |
| CH->setExceptionVarIndex(EHObjIndexVal); |
| Actions.push_back(CH); |
| } else if (ActionKind == 0) { |
| Constant *Handler = cast<Constant>(II->getArgOperand(I + 1)); |
| I += 2; |
| auto *CH = new CleanupHandler(/*BB=*/nullptr); |
| CH->setHandlerBlockOrFunc(Handler); |
| Actions.push_back(CH); |
| } else { |
| llvm_unreachable("Expected either a catch or cleanup handler!"); |
| } |
| } |
| std::reverse(Actions.begin(), Actions.end()); |
| } |