-//===-- WinEHPrepare - Prepare exception handling for code generation ---===//\r
-//\r
-// The LLVM Compiler Infrastructure\r
-//\r
-// This file is distributed under the University of Illinois Open Source\r
-// License. See LICENSE.TXT for details.\r
-//\r
-//===----------------------------------------------------------------------===//\r
-//\r
-// This pass lowers LLVM IR exception handling into something closer to what the\r
-// backend wants. It snifs the personality function to see which kind of\r
-// preparation is necessary. If the personality function uses the Itanium LSDA,\r
-// this pass delegates to the DWARF EH preparation pass.\r
-//\r
-//===----------------------------------------------------------------------===//\r
-\r
-#include "llvm/CodeGen/Passes.h"\r
-#include "llvm/ADT/MapVector.h"\r
-#include "llvm/ADT/TinyPtrVector.h"\r
-#include "llvm/Analysis/LibCallSemantics.h"\r
-#include "llvm/IR/Function.h"\r
-#include "llvm/IR/IRBuilder.h"\r
-#include "llvm/IR/Instructions.h"\r
-#include "llvm/IR/IntrinsicInst.h"\r
-#include "llvm/IR/Module.h"\r
-#include "llvm/IR/PatternMatch.h"\r
-#include "llvm/Pass.h"\r
-#include "llvm/Transforms/Utils/Cloning.h"\r
-#include "llvm/Transforms/Utils/Local.h"\r
-#include <memory>\r
-\r
-using namespace llvm;\r
-using namespace llvm::PatternMatch;\r
-\r
-#define DEBUG_TYPE "winehprepare"\r
-\r
-namespace {\r
-\r
-struct HandlerAllocas {\r
- TinyPtrVector<AllocaInst *> Allocas;\r
- int ParentFrameAllocationIndex;\r
-};\r
-\r
-// This map is used to model frame variable usage during outlining, to\r
-// construct a structure type to hold the frame variables in a frame\r
-// allocation block, and to remap the frame variable allocas (including\r
-// spill locations as needed) to GEPs that get the variable from the\r
-// frame allocation structure.\r
-typedef MapVector<AllocaInst *, HandlerAllocas> FrameVarInfoMap;\r
-\r
-class WinEHPrepare : public FunctionPass {\r
- std::unique_ptr<FunctionPass> DwarfPrepare;\r
-\r
-public:\r
- static char ID; // Pass identification, replacement for typeid.\r
- WinEHPrepare(const TargetMachine *TM = nullptr)\r
- : FunctionPass(ID), DwarfPrepare(createDwarfEHPass(TM)) {}\r
-\r
- bool runOnFunction(Function &Fn) override;\r
-\r
- bool doFinalization(Module &M) override;\r
-\r
- void getAnalysisUsage(AnalysisUsage &AU) const override;\r
-\r
- const char *getPassName() const override {\r
- return "Windows exception handling preparation";\r
- }\r
-\r
-private:\r
- bool prepareCPPEHHandlers(Function &F,\r
- SmallVectorImpl<LandingPadInst *> &LPads);\r
- bool outlineCatchHandler(Function *SrcFn, Constant *SelectorType,\r
- LandingPadInst *LPad, CallInst *&EHAlloc,\r
- AllocaInst *&EHObjPtr, FrameVarInfoMap &VarInfo);\r
-};\r
-\r
-class WinEHFrameVariableMaterializer : public ValueMaterializer {\r
-public:\r
- WinEHFrameVariableMaterializer(Function *OutlinedFn,\r
- FrameVarInfoMap &FrameVarInfo);\r
- ~WinEHFrameVariableMaterializer() {}\r
-\r
- virtual Value *materializeValueFor(Value *V) override;\r
-\r
-private:\r
- FrameVarInfoMap &FrameVarInfo;\r
- IRBuilder<> Builder;\r
-};\r
-\r
-class WinEHCatchDirector : public CloningDirector {\r
-public:\r
- WinEHCatchDirector(LandingPadInst *LPI, Function *CatchFn, Value *Selector,\r
- Value *EHObj, FrameVarInfoMap &VarInfo)\r
- : LPI(LPI), CurrentSelector(Selector->stripPointerCasts()), EHObj(EHObj),\r
- Materializer(CatchFn, VarInfo),\r
- SelectorIDType(Type::getInt32Ty(LPI->getContext())),\r
- Int8PtrType(Type::getInt8PtrTy(LPI->getContext())) {}\r
-\r
- CloningAction handleInstruction(ValueToValueMapTy &VMap,\r
- const Instruction *Inst,\r
- BasicBlock *NewBB) override;\r
-\r
- ValueMaterializer *getValueMaterializer() override { return &Materializer; }\r
-\r
-private:\r
- LandingPadInst *LPI;\r
- Value *CurrentSelector;\r
- Value *EHObj;\r
- WinEHFrameVariableMaterializer Materializer;\r
- Type *SelectorIDType;\r
- Type *Int8PtrType;\r
-\r
- const Value *ExtractedEHPtr;\r
- const Value *ExtractedSelector;\r
- const Value *EHPtrStoreAddr;\r
- const Value *SelectorStoreAddr;\r
-};\r
-} // end anonymous namespace\r
-\r
-char WinEHPrepare::ID = 0;\r
-INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions",\r
- false, false)\r
-\r
-FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) {\r
- return new WinEHPrepare(TM);\r
-}\r
-\r
-static bool isMSVCPersonality(EHPersonality Pers) {\r
- return Pers == EHPersonality::MSVC_Win64SEH ||\r
- Pers == EHPersonality::MSVC_CXX;\r
-}\r
-\r
-bool WinEHPrepare::runOnFunction(Function &Fn) {\r
- SmallVector<LandingPadInst *, 4> LPads;\r
- SmallVector<ResumeInst *, 4> Resumes;\r
- for (BasicBlock &BB : Fn) {\r
- if (auto *LP = BB.getLandingPadInst())\r
- LPads.push_back(LP);\r
- if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator()))\r
- Resumes.push_back(Resume);\r
- }\r
-\r
- // No need to prepare functions that lack landing pads.\r
- if (LPads.empty())\r
- return false;\r
-\r
- // Classify the personality to see what kind of preparation we need.\r
- EHPersonality Pers = classifyEHPersonality(LPads.back()->getPersonalityFn());\r
-\r
- // Delegate through to the DWARF pass if this is unrecognized.\r
- if (!isMSVCPersonality(Pers))\r
- return DwarfPrepare->runOnFunction(Fn);\r
-\r
- // FIXME: This only returns true if the C++ EH handlers were outlined.\r
- // When that code is complete, it should always return whatever\r
- // prepareCPPEHHandlers returns.\r
- if (Pers == EHPersonality::MSVC_CXX && prepareCPPEHHandlers(Fn, LPads))\r
- return true;\r
-\r
- // FIXME: SEH Cleanups are unimplemented. Replace them with unreachable.\r
- if (Resumes.empty())\r
- return false;\r
-\r
- for (ResumeInst *Resume : Resumes) {\r
- IRBuilder<>(Resume).CreateUnreachable();\r
- Resume->eraseFromParent();\r
- }\r
-\r
- return true;\r
-}\r
-\r
-bool WinEHPrepare::doFinalization(Module &M) {\r
- return DwarfPrepare->doFinalization(M);\r
-}\r
-\r
-void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {\r
- DwarfPrepare->getAnalysisUsage(AU);\r
-}\r
-\r
-bool WinEHPrepare::prepareCPPEHHandlers(\r
- Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {\r
- // These containers are used to re-map frame variables that are used in\r
- // outlined catch and cleanup handlers. They will be populated as the\r
- // handlers are outlined.\r
- FrameVarInfoMap FrameVarInfo;\r
- SmallVector<CallInst *, 4> HandlerAllocs;\r
- SmallVector<AllocaInst *, 4> HandlerEHObjPtrs;\r
-\r
- bool HandlersOutlined = false;\r
-\r
- for (LandingPadInst *LPad : LPads) {\r
- // Look for evidence that this landingpad has already been processed.\r
- bool LPadHasActionList = false;\r
- BasicBlock *LPadBB = LPad->getParent();\r
- for (Instruction &Inst : LPadBB->getInstList()) {\r
- // FIXME: Make this an intrinsic.\r
- if (auto *Call = dyn_cast<CallInst>(&Inst))\r
- if (Call->getCalledFunction()->getName() == "llvm.eh.actions") {\r
- LPadHasActionList = true;\r
- break;\r
- }\r
- }\r
-\r
- // If we've already outlined the handlers for this landingpad,\r
- // there's nothing more to do here.\r
- if (LPadHasActionList)\r
- continue;\r
-\r
- for (unsigned Idx = 0, NumClauses = LPad->getNumClauses(); Idx < NumClauses;\r
- ++Idx) {\r
- if (LPad->isCatch(Idx)) {\r
- // Create a new instance of the handler data structure in the\r
- // HandlerData vector.\r
- CallInst *EHAlloc = nullptr;\r
- AllocaInst *EHObjPtr = nullptr;\r
- bool Outlined = outlineCatchHandler(&F, LPad->getClause(Idx), LPad,\r
- EHAlloc, EHObjPtr, FrameVarInfo);\r
- if (Outlined) {\r
- HandlersOutlined = true;\r
- // These values must be resolved after all handlers have been\r
- // outlined.\r
- if (EHAlloc)\r
- HandlerAllocs.push_back(EHAlloc);\r
- if (EHObjPtr)\r
- HandlerEHObjPtrs.push_back(EHObjPtr);\r
- }\r
- } // End if (isCatch)\r
- } // End for each clause\r
- } // End for each landingpad\r
-\r
- // If nothing got outlined, there is no more processing to be done.\r
- if (!HandlersOutlined)\r
- return false;\r
-\r
- // FIXME: We will replace the landingpad bodies with llvm.eh.actions\r
- // calls and indirect branches here and then delete blocks\r
- // which are no longer reachable. That will get rid of the\r
- // handlers that we have outlined. There is code below\r
- // that looks for allocas with no uses in the parent function.\r
- // That will only happen after the pruning is implemented.\r
-\r
- // Remap the frame variables.\r
- SmallVector<Type *, 2> StructTys;\r
- StructTys.push_back(Type::getInt32Ty(F.getContext())); // EH state\r
- StructTys.push_back(Type::getInt8PtrTy(F.getContext())); // EH object\r
-\r
- // Start the index at two since we always have the above fields at 0 and 1.\r
- int Idx = 2;\r
-\r
- // FIXME: Sort the FrameVarInfo vector by the ParentAlloca size and alignment\r
- // and add padding as necessary to provide the proper alignment.\r
-\r
- // Map the alloca instructions to the corresponding index in the\r
- // frame allocation structure. If any alloca is used only in a single\r
- // handler and is not used in the parent frame after outlining, it will\r
- // be assigned an index of -1, meaning the handler can keep its\r
- // "temporary" alloca and the original alloca can be erased from the\r
- // parent function. If we later encounter this alloca in a second\r
- // handler, we will assign it a place in the frame allocation structure\r
- // at that time. Since the instruction replacement doesn't happen until\r
- // all the entries in the HandlerData have been processed this isn't a\r
- // problem.\r
- for (auto &VarInfoEntry : FrameVarInfo) {\r
- AllocaInst *ParentAlloca = VarInfoEntry.first;\r
- HandlerAllocas &AllocaInfo = VarInfoEntry.second;\r
-\r
- // If the instruction still has uses in the parent function or if it is\r
- // referenced by more than one handler, add it to the frame allocation\r
- // structure.\r
- if (ParentAlloca->getNumUses() != 0 || AllocaInfo.Allocas.size() > 1) {\r
- Type *VarTy = ParentAlloca->getAllocatedType();\r
- StructTys.push_back(VarTy);\r
- AllocaInfo.ParentFrameAllocationIndex = Idx++;\r
- } else {\r
- // If the variable is not used in the parent frame and it is only used\r
- // in one handler, the alloca can be removed from the parent frame\r
- // and the handler will keep its "temporary" alloca to define the value.\r
- // An element index of -1 is used to indicate this condition.\r
- AllocaInfo.ParentFrameAllocationIndex = -1;\r
- }\r
- }\r
-\r
- // Having filled the StructTys vector and assigned an index to each element,\r
- // we can now create the structure.\r
- StructType *EHDataStructTy = StructType::create(\r
- F.getContext(), StructTys, "struct." + F.getName().str() + ".ehdata");\r
- IRBuilder<> Builder(F.getParent()->getContext());\r
-\r
- // Create a frame allocation.\r
- Module *M = F.getParent();\r
- LLVMContext &Context = M->getContext();\r
- BasicBlock *Entry = &F.getEntryBlock();\r
- Builder.SetInsertPoint(Entry->getFirstInsertionPt());\r
- Function *FrameAllocFn =\r
- Intrinsic::getDeclaration(M, Intrinsic::frameallocate);\r
- uint64_t EHAllocSize = M->getDataLayout()->getTypeAllocSize(EHDataStructTy);\r
- Value *FrameAllocArgs[] = {\r
- ConstantInt::get(Type::getInt32Ty(Context), EHAllocSize)};\r
- CallInst *FrameAlloc =\r
- Builder.CreateCall(FrameAllocFn, FrameAllocArgs, "frame.alloc");\r
-\r
- Value *FrameEHData = Builder.CreateBitCast(\r
- FrameAlloc, EHDataStructTy->getPointerTo(), "eh.data");\r
-\r
- // Now visit each handler that is using the structure and bitcast its EHAlloc\r
- // value to be a pointer to the frame alloc structure.\r
- DenseMap<Function *, Value *> EHDataMap;\r
- for (CallInst *EHAlloc : HandlerAllocs) {\r
- // The EHAlloc has no uses at this time, so we need to just insert the\r
- // cast before the next instruction. There is always a next instruction.\r
- BasicBlock::iterator II = EHAlloc;\r
- ++II;\r
- Builder.SetInsertPoint(cast<Instruction>(II));\r
- Value *EHData = Builder.CreateBitCast(\r
- EHAlloc, EHDataStructTy->getPointerTo(), "eh.data");\r
- EHDataMap[EHAlloc->getParent()->getParent()] = EHData;\r
- }\r
-\r
- // Next, replace the place-holder EHObjPtr allocas with GEP instructions\r
- // that pull the EHObjPtr from the frame alloc structure\r
- for (AllocaInst *EHObjPtr : HandlerEHObjPtrs) {\r
- Value *EHData = EHDataMap[EHObjPtr->getParent()->getParent()];\r
- Value *ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, 1);\r
- EHObjPtr->replaceAllUsesWith(ElementPtr);\r
- EHObjPtr->removeFromParent();\r
- ElementPtr->takeName(EHObjPtr);\r
- delete EHObjPtr;\r
- }\r
-\r
- // Finally, replace all of the temporary allocas for frame variables used in\r
- // the outlined handlers and the original frame allocas with GEP instructions\r
- // that get the equivalent pointer from the frame allocation struct.\r
- for (auto &VarInfoEntry : FrameVarInfo) {\r
- AllocaInst *ParentAlloca = VarInfoEntry.first;\r
- HandlerAllocas &AllocaInfo = VarInfoEntry.second;\r
- int Idx = AllocaInfo.ParentFrameAllocationIndex;\r
-\r
- // If we have an index of -1 for this instruction, it means it isn't used\r
- // outside of this handler. In that case, we just keep the "temporary"\r
- // alloca in the handler and erase the original alloca from the parent.\r
- if (Idx == -1) {\r
- ParentAlloca->eraseFromParent();\r
- } else {\r
- // Otherwise, we replace the parent alloca and all outlined allocas\r
- // which map to it with GEP instructions.\r
-\r
- // First replace the original alloca.\r
- Builder.SetInsertPoint(ParentAlloca);\r
- Builder.SetCurrentDebugLocation(ParentAlloca->getDebugLoc());\r
- Value *ElementPtr =\r
- Builder.CreateConstInBoundsGEP2_32(FrameEHData, 0, Idx);\r
- ParentAlloca->replaceAllUsesWith(ElementPtr);\r
- ParentAlloca->removeFromParent();\r
- ElementPtr->takeName(ParentAlloca);\r
- delete ParentAlloca;\r
-\r
- // Next replace all outlined allocas that are mapped to it.\r
- for (AllocaInst *TempAlloca : AllocaInfo.Allocas) {\r
- Value *EHData = EHDataMap[TempAlloca->getParent()->getParent()];\r
- // FIXME: Sink this GEP into the blocks where it is used.\r
- Builder.SetInsertPoint(TempAlloca);\r
- Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());\r
- ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, Idx);\r
- TempAlloca->replaceAllUsesWith(ElementPtr);\r
- TempAlloca->removeFromParent();\r
- ElementPtr->takeName(TempAlloca);\r
- delete TempAlloca;\r
- }\r
- } // end else of if (Idx == -1)\r
- } // End for each FrameVarInfo entry.\r
-\r
- return HandlersOutlined;\r
-}\r
-\r
-bool WinEHPrepare::outlineCatchHandler(Function *SrcFn, Constant *SelectorType,\r
- LandingPadInst *LPad, CallInst *&EHAlloc,\r
- AllocaInst *&EHObjPtr,\r
- FrameVarInfoMap &VarInfo) {\r
- Module *M = SrcFn->getParent();\r
- LLVMContext &Context = M->getContext();\r
-\r
- // Create a new function to receive the handler contents.\r
- Type *Int8PtrType = Type::getInt8PtrTy(Context);\r
- std::vector<Type *> ArgTys;\r
- ArgTys.push_back(Int8PtrType);\r
- ArgTys.push_back(Int8PtrType);\r
- FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);\r
- Function *CatchHandler = Function::Create(\r
- FnType, GlobalVariable::ExternalLinkage, SrcFn->getName() + ".catch", M);\r
-\r
- // Generate a standard prolog to setup the frame recovery structure.\r
- IRBuilder<> Builder(Context);\r
- BasicBlock *Entry = BasicBlock::Create(Context, "catch.entry");\r
- CatchHandler->getBasicBlockList().push_front(Entry);\r
- Builder.SetInsertPoint(Entry);\r
- Builder.SetCurrentDebugLocation(LPad->getDebugLoc());\r
-\r
- // The outlined handler will be called with the parent's frame pointer as\r
- // its second argument. To enable the handler to access variables from\r
- // the parent frame, we use that pointer to get locate a special block\r
- // of memory that was allocated using llvm.eh.allocateframe for this\r
- // purpose. During the outlining process we will determine which frame\r
- // variables are used in handlers and create a structure that maps these\r
- // variables into the frame allocation block.\r
- //\r
- // The frame allocation block also contains an exception state variable\r
- // used by the runtime and a pointer to the exception object pointer\r
- // which will be filled in by the runtime for use in the handler.\r
- Function *RecoverFrameFn =\r
- Intrinsic::getDeclaration(M, Intrinsic::framerecover);\r
- Value *RecoverArgs[] = {Builder.CreateBitCast(SrcFn, Int8PtrType, ""),\r
- &(CatchHandler->getArgumentList().back())};\r
- EHAlloc = Builder.CreateCall(RecoverFrameFn, RecoverArgs, "eh.alloc");\r
-\r
- // This alloca is only temporary. We'll be replacing it once we know all the\r
- // frame variables that need to go in the frame allocation structure.\r
- EHObjPtr = Builder.CreateAlloca(Int8PtrType, 0, "eh.obj.ptr");\r
-\r
- // This will give us a raw pointer to the exception object, which\r
- // corresponds to the formal parameter of the catch statement. If the\r
- // handler uses this object, we will generate code during the outlining\r
- // process to cast the pointer to the appropriate type and deference it\r
- // as necessary. The un-outlined landing pad code represents the\r
- // exception object as the result of the llvm.eh.begincatch call.\r
- Value *EHObj = Builder.CreateLoad(EHObjPtr, false, "eh.obj");\r
-\r
- ValueToValueMapTy VMap;\r
-\r
- // FIXME: Map other values referenced in the filter handler.\r
-\r
- WinEHCatchDirector Director(LPad, CatchHandler, SelectorType, EHObj, VarInfo);\r
-\r
- SmallVector<ReturnInst *, 8> Returns;\r
- ClonedCodeInfo InlinedFunctionInfo;\r
-\r
- BasicBlock::iterator II = LPad;\r
-\r
- CloneAndPruneIntoFromInst(CatchHandler, SrcFn, ++II, VMap,\r
- /*ModuleLevelChanges=*/false, Returns, "",\r
- &InlinedFunctionInfo,\r
- SrcFn->getParent()->getDataLayout(), &Director);\r
-\r
- // Move all the instructions in the first cloned block into our entry block.\r
- BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry));\r
- Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList());\r
- FirstClonedBB->eraseFromParent();\r
-\r
- return true;\r
-}\r
-\r
-CloningDirector::CloningAction WinEHCatchDirector::handleInstruction(\r
- ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {\r
- // Intercept instructions which extract values from the landing pad aggregate.\r
- if (auto *Extract = dyn_cast<ExtractValueInst>(Inst)) {\r
- if (Extract->getAggregateOperand() == LPI) {\r
- assert(Extract->getNumIndices() == 1 &&\r
- "Unexpected operation: extracting both landing pad values");\r
- assert((*(Extract->idx_begin()) == 0 || *(Extract->idx_begin()) == 1) &&\r
- "Unexpected operation: extracting an unknown landing pad element");\r
-\r
- if (*(Extract->idx_begin()) == 0) {\r
- // Element 0 doesn't directly corresponds to anything in the WinEH\r
- // scheme.\r
- // It will be stored to a memory location, then later loaded and finally\r
- // the loaded value will be used as the argument to an\r
- // llvm.eh.begincatch\r
- // call. We're tracking it here so that we can skip the store and load.\r
- ExtractedEHPtr = Inst;\r
- } else {\r
- // Element 1 corresponds to the filter selector. We'll map it to 1 for\r
- // matching purposes, but it will also probably be stored to memory and\r
- // reloaded, so we need to track the instuction so that we can map the\r
- // loaded value too.\r
- VMap[Inst] = ConstantInt::get(SelectorIDType, 1);\r
- ExtractedSelector = Inst;\r
- }\r
-\r
- // Tell the caller not to clone this instruction.\r
- return CloningDirector::SkipInstruction;\r
- }\r
- // Other extract value instructions just get cloned.\r
- return CloningDirector::CloneInstruction;\r
- }\r
-\r
- if (auto *Store = dyn_cast<StoreInst>(Inst)) {\r
- // Look for and suppress stores of the extracted landingpad values.\r
- const Value *StoredValue = Store->getValueOperand();\r
- if (StoredValue == ExtractedEHPtr) {\r
- EHPtrStoreAddr = Store->getPointerOperand();\r
- return CloningDirector::SkipInstruction;\r
- }\r
- if (StoredValue == ExtractedSelector) {\r
- SelectorStoreAddr = Store->getPointerOperand();\r
- return CloningDirector::SkipInstruction;\r
- }\r
-\r
- // Any other store just gets cloned.\r
- return CloningDirector::CloneInstruction;\r
- }\r
-\r
- if (auto *Load = dyn_cast<LoadInst>(Inst)) {\r
- // Look for loads of (previously suppressed) landingpad values.\r
- // The EHPtr load can be ignored (it should only be used as\r
- // an argument to llvm.eh.begincatch), but the selector value\r
- // needs to be mapped to a constant value of 1 to be used to\r
- // simplify the branching to always flow to the current handler.\r
- const Value *LoadAddr = Load->getPointerOperand();\r
- if (LoadAddr == EHPtrStoreAddr) {\r
- VMap[Inst] = UndefValue::get(Int8PtrType);\r
- return CloningDirector::SkipInstruction;\r
- }\r
- if (LoadAddr == SelectorStoreAddr) {\r
- VMap[Inst] = ConstantInt::get(SelectorIDType, 1);\r
- return CloningDirector::SkipInstruction;\r
- }\r
-\r
- // Any other loads just get cloned.\r
- return CloningDirector::CloneInstruction;\r
- }\r
-\r
- if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) {\r
- // The argument to the call is some form of the first element of the\r
- // landingpad aggregate value, but that doesn't matter. It isn't used\r
- // here.\r
- // The return value of this instruction, however, is used to access the\r
- // EH object pointer. We have generated an instruction to get that value\r
- // from the EH alloc block, so we can just map to that here.\r
- VMap[Inst] = EHObj;\r
- return CloningDirector::SkipInstruction;\r
- }\r
- if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) {\r
- auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);\r
- // It might be interesting to track whether or not we are inside a catch\r
- // function, but that might make the algorithm more brittle than it needs\r
- // to be.\r
-\r
- // The end catch call can occur in one of two places: either in a\r
- // landingpad\r
- // block that is part of the catch handlers exception mechanism, or at the\r
- // end of the catch block. If it occurs in a landing pad, we must skip it\r
- // and continue so that the landing pad gets cloned.\r
- // FIXME: This case isn't fully supported yet and shouldn't turn up in any\r
- // of the test cases until it is.\r
- if (IntrinCall->getParent()->isLandingPad())\r
- return CloningDirector::SkipInstruction;\r
-\r
- // If an end catch occurs anywhere else the next instruction should be an\r
- // unconditional branch instruction that we want to replace with a return\r
- // to the the address of the branch target.\r
- const BasicBlock *EndCatchBB = IntrinCall->getParent();\r
- const TerminatorInst *Terminator = EndCatchBB->getTerminator();\r
- const BranchInst *Branch = dyn_cast<BranchInst>(Terminator);\r
- assert(Branch && Branch->isUnconditional());\r
- assert(std::next(BasicBlock::const_iterator(IntrinCall)) ==\r
- BasicBlock::const_iterator(Branch));\r
-\r
- ReturnInst::Create(NewBB->getContext(),\r
- BlockAddress::get(Branch->getSuccessor(0)), NewBB);\r
-\r
- // We just added a terminator to the cloned block.\r
- // Tell the caller to stop processing the current basic block so that\r
- // the branch instruction will be skipped.\r
- return CloningDirector::StopCloningBB;\r
- }\r
- if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) {\r
- auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);\r
- Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();\r
- // This causes a replacement that will collapse the landing pad CFG based\r
- // on the filter function we intend to match.\r
- if (Selector == CurrentSelector)\r
- VMap[Inst] = ConstantInt::get(SelectorIDType, 1);\r
- else\r
- VMap[Inst] = ConstantInt::get(SelectorIDType, 0);\r
- // Tell the caller not to clone this instruction.\r
- return CloningDirector::SkipInstruction;\r
- }\r
-\r
- // Continue with the default cloning behavior.\r
- return CloningDirector::CloneInstruction;\r
-}\r
-\r
-WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(\r
- Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)\r
- : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {\r
- Builder.SetInsertPoint(&OutlinedFn->getEntryBlock());\r
- // FIXME: Do something with the FrameVarMapped so that it is shared across the\r
- // function.\r
-}\r
-\r
-Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {\r
- // If we're asked to materialize an alloca variable, we temporarily\r
- // create a matching alloca in the outlined function. When all the\r
- // outlining is complete, we'll collect these into a structure and\r
- // replace these temporary allocas with GEPs referencing the frame\r
- // allocation block.\r
- if (auto *AV = dyn_cast<AllocaInst>(V)) {\r
- AllocaInst *NewAlloca = Builder.CreateAlloca(\r
- AV->getAllocatedType(), AV->getArraySize(), AV->getName());\r
- FrameVarInfo[AV].Allocas.push_back(NewAlloca);\r
- return NewAlloca;\r
- }\r
-\r
-// FIXME: Do PHI nodes need special handling?\r
-\r
-// FIXME: Are there other cases we can handle better? GEP, ExtractValue, etc.\r
-\r
-// FIXME: This doesn't work during cloning because it finds an instruction\r
-// in the use list that isn't yet part of a basic block.\r
-#if 0\r
- // If we're asked to remap some other instruction, we'll need to\r
- // spill it to an alloca variable in the parent function and add a\r
- // temporary alloca in the outlined function to be processed as\r
- // described above.\r
- Instruction *Inst = dyn_cast<Instruction>(V);\r
- if (Inst) {\r
- AllocaInst *Spill = DemoteRegToStack(*Inst, true);\r
- AllocaInst *NewAlloca = Builder.CreateAlloca(Spill->getAllocatedType(),\r
- Spill->getArraySize());\r
- FrameVarMap[AV] = NewAlloca;\r
- return NewAlloca;\r
- }\r
-#endif\r
-\r
- return nullptr;\r
-}\r
+//===-- 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/TinyPtrVector.h"
+#include "llvm/Analysis/LibCallSemantics.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/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include <memory>
+
+using namespace llvm;
+using namespace llvm::PatternMatch;
+
+#define DEBUG_TYPE "winehprepare"
+
+namespace {
+
+struct HandlerAllocas {
+ TinyPtrVector<AllocaInst *> Allocas;
+ int ParentFrameAllocationIndex;
+};
+
+// This map is used to model frame variable usage during outlining, to
+// construct a structure type to hold the frame variables in a frame
+// allocation block, and to remap the frame variable allocas (including
+// spill locations as needed) to GEPs that get the variable from the
+// frame allocation structure.
+typedef MapVector<AllocaInst *, HandlerAllocas> FrameVarInfoMap;
+
+class WinEHPrepare : public FunctionPass {
+ std::unique_ptr<FunctionPass> DwarfPrepare;
+
+public:
+ static char ID; // Pass identification, replacement for typeid.
+ WinEHPrepare(const TargetMachine *TM = nullptr)
+ : FunctionPass(ID), DwarfPrepare(createDwarfEHPass(TM)) {}
+
+ 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 prepareCPPEHHandlers(Function &F,
+ SmallVectorImpl<LandingPadInst *> &LPads);
+ bool outlineCatchHandler(Function *SrcFn, Constant *SelectorType,
+ LandingPadInst *LPad, CallInst *&EHAlloc,
+ AllocaInst *&EHObjPtr, FrameVarInfoMap &VarInfo);
+};
+
+class WinEHFrameVariableMaterializer : public ValueMaterializer {
+public:
+ WinEHFrameVariableMaterializer(Function *OutlinedFn,
+ FrameVarInfoMap &FrameVarInfo);
+ ~WinEHFrameVariableMaterializer() {}
+
+ virtual Value *materializeValueFor(Value *V) override;
+
+private:
+ FrameVarInfoMap &FrameVarInfo;
+ IRBuilder<> Builder;
+};
+
+class WinEHCatchDirector : public CloningDirector {
+public:
+ WinEHCatchDirector(LandingPadInst *LPI, Function *CatchFn, Value *Selector,
+ Value *EHObj, FrameVarInfoMap &VarInfo)
+ : LPI(LPI), CurrentSelector(Selector->stripPointerCasts()), EHObj(EHObj),
+ Materializer(CatchFn, VarInfo),
+ SelectorIDType(Type::getInt32Ty(LPI->getContext())),
+ Int8PtrType(Type::getInt8PtrTy(LPI->getContext())) {}
+
+ CloningAction handleInstruction(ValueToValueMapTy &VMap,
+ const Instruction *Inst,
+ BasicBlock *NewBB) override;
+
+ ValueMaterializer *getValueMaterializer() override { return &Materializer; }
+
+private:
+ LandingPadInst *LPI;
+ Value *CurrentSelector;
+ Value *EHObj;
+ WinEHFrameVariableMaterializer Materializer;
+ Type *SelectorIDType;
+ Type *Int8PtrType;
+
+ const Value *ExtractedEHPtr;
+ const Value *ExtractedSelector;
+ const Value *EHPtrStoreAddr;
+ const Value *SelectorStoreAddr;
+};
+} // 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);
+}
+
+static bool isMSVCPersonality(EHPersonality Pers) {
+ return Pers == EHPersonality::MSVC_Win64SEH ||
+ Pers == EHPersonality::MSVC_CXX;
+}
+
+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.
+ EHPersonality Pers = classifyEHPersonality(LPads.back()->getPersonalityFn());
+
+ // Delegate through to the DWARF pass if this is unrecognized.
+ if (!isMSVCPersonality(Pers))
+ return DwarfPrepare->runOnFunction(Fn);
+
+ // FIXME: This only returns true if the C++ EH handlers were outlined.
+ // When that code is complete, it should always return whatever
+ // prepareCPPEHHandlers returns.
+ if (Pers == EHPersonality::MSVC_CXX && prepareCPPEHHandlers(Fn, LPads))
+ return true;
+
+ // FIXME: SEH Cleanups are unimplemented. Replace them with unreachable.
+ if (Resumes.empty())
+ return false;
+
+ for (ResumeInst *Resume : Resumes) {
+ IRBuilder<>(Resume).CreateUnreachable();
+ Resume->eraseFromParent();
+ }
+
+ return true;
+}
+
+bool WinEHPrepare::doFinalization(Module &M) {
+ return DwarfPrepare->doFinalization(M);
+}
+
+void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
+ DwarfPrepare->getAnalysisUsage(AU);
+}
+
+bool WinEHPrepare::prepareCPPEHHandlers(
+ Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
+ // These containers are used to re-map frame variables that are used in
+ // outlined catch and cleanup handlers. They will be populated as the
+ // handlers are outlined.
+ FrameVarInfoMap FrameVarInfo;
+ SmallVector<CallInst *, 4> HandlerAllocs;
+ SmallVector<AllocaInst *, 4> HandlerEHObjPtrs;
+
+ bool HandlersOutlined = false;
+
+ for (LandingPadInst *LPad : LPads) {
+ // Look for evidence that this landingpad has already been processed.
+ bool LPadHasActionList = false;
+ BasicBlock *LPadBB = LPad->getParent();
+ for (Instruction &Inst : LPadBB->getInstList()) {
+ // FIXME: Make this an intrinsic.
+ if (auto *Call = dyn_cast<CallInst>(&Inst))
+ if (Call->getCalledFunction()->getName() == "llvm.eh.actions") {
+ LPadHasActionList = true;
+ break;
+ }
+ }
+
+ // If we've already outlined the handlers for this landingpad,
+ // there's nothing more to do here.
+ if (LPadHasActionList)
+ continue;
+
+ for (unsigned Idx = 0, NumClauses = LPad->getNumClauses(); Idx < NumClauses;
+ ++Idx) {
+ if (LPad->isCatch(Idx)) {
+ // Create a new instance of the handler data structure in the
+ // HandlerData vector.
+ CallInst *EHAlloc = nullptr;
+ AllocaInst *EHObjPtr = nullptr;
+ bool Outlined = outlineCatchHandler(&F, LPad->getClause(Idx), LPad,
+ EHAlloc, EHObjPtr, FrameVarInfo);
+ if (Outlined) {
+ HandlersOutlined = true;
+ // These values must be resolved after all handlers have been
+ // outlined.
+ if (EHAlloc)
+ HandlerAllocs.push_back(EHAlloc);
+ if (EHObjPtr)
+ HandlerEHObjPtrs.push_back(EHObjPtr);
+ }
+ } // End if (isCatch)
+ } // End for each clause
+ } // End for each landingpad
+
+ // If nothing got outlined, there is no more processing to be done.
+ if (!HandlersOutlined)
+ return false;
+
+ // FIXME: We will replace the landingpad bodies with llvm.eh.actions
+ // calls and indirect branches here and then delete blocks
+ // which are no longer reachable. That will get rid of the
+ // handlers that we have outlined. There is code below
+ // that looks for allocas with no uses in the parent function.
+ // That will only happen after the pruning is implemented.
+
+ // Remap the frame variables.
+ SmallVector<Type *, 2> StructTys;
+ StructTys.push_back(Type::getInt32Ty(F.getContext())); // EH state
+ StructTys.push_back(Type::getInt8PtrTy(F.getContext())); // EH object
+
+ // Start the index at two since we always have the above fields at 0 and 1.
+ int Idx = 2;
+
+ // FIXME: Sort the FrameVarInfo vector by the ParentAlloca size and alignment
+ // and add padding as necessary to provide the proper alignment.
+
+ // Map the alloca instructions to the corresponding index in the
+ // frame allocation structure. If any alloca is used only in a single
+ // handler and is not used in the parent frame after outlining, it will
+ // be assigned an index of -1, meaning the handler can keep its
+ // "temporary" alloca and the original alloca can be erased from the
+ // parent function. If we later encounter this alloca in a second
+ // handler, we will assign it a place in the frame allocation structure
+ // at that time. Since the instruction replacement doesn't happen until
+ // all the entries in the HandlerData have been processed this isn't a
+ // problem.
+ for (auto &VarInfoEntry : FrameVarInfo) {
+ AllocaInst *ParentAlloca = VarInfoEntry.first;
+ HandlerAllocas &AllocaInfo = VarInfoEntry.second;
+
+ // If the instruction still has uses in the parent function or if it is
+ // referenced by more than one handler, add it to the frame allocation
+ // structure.
+ if (ParentAlloca->getNumUses() != 0 || AllocaInfo.Allocas.size() > 1) {
+ Type *VarTy = ParentAlloca->getAllocatedType();
+ StructTys.push_back(VarTy);
+ AllocaInfo.ParentFrameAllocationIndex = Idx++;
+ } else {
+ // If the variable is not used in the parent frame and it is only used
+ // in one handler, the alloca can be removed from the parent frame
+ // and the handler will keep its "temporary" alloca to define the value.
+ // An element index of -1 is used to indicate this condition.
+ AllocaInfo.ParentFrameAllocationIndex = -1;
+ }
+ }
+
+ // Having filled the StructTys vector and assigned an index to each element,
+ // we can now create the structure.
+ StructType *EHDataStructTy = StructType::create(
+ F.getContext(), StructTys, "struct." + F.getName().str() + ".ehdata");
+ IRBuilder<> Builder(F.getParent()->getContext());
+
+ // Create a frame allocation.
+ Module *M = F.getParent();
+ LLVMContext &Context = M->getContext();
+ BasicBlock *Entry = &F.getEntryBlock();
+ Builder.SetInsertPoint(Entry->getFirstInsertionPt());
+ Function *FrameAllocFn =
+ Intrinsic::getDeclaration(M, Intrinsic::frameallocate);
+ uint64_t EHAllocSize = M->getDataLayout()->getTypeAllocSize(EHDataStructTy);
+ Value *FrameAllocArgs[] = {
+ ConstantInt::get(Type::getInt32Ty(Context), EHAllocSize)};
+ CallInst *FrameAlloc =
+ Builder.CreateCall(FrameAllocFn, FrameAllocArgs, "frame.alloc");
+
+ Value *FrameEHData = Builder.CreateBitCast(
+ FrameAlloc, EHDataStructTy->getPointerTo(), "eh.data");
+
+ // Now visit each handler that is using the structure and bitcast its EHAlloc
+ // value to be a pointer to the frame alloc structure.
+ DenseMap<Function *, Value *> EHDataMap;
+ for (CallInst *EHAlloc : HandlerAllocs) {
+ // The EHAlloc has no uses at this time, so we need to just insert the
+ // cast before the next instruction. There is always a next instruction.
+ BasicBlock::iterator II = EHAlloc;
+ ++II;
+ Builder.SetInsertPoint(cast<Instruction>(II));
+ Value *EHData = Builder.CreateBitCast(
+ EHAlloc, EHDataStructTy->getPointerTo(), "eh.data");
+ EHDataMap[EHAlloc->getParent()->getParent()] = EHData;
+ }
+
+ // Next, replace the place-holder EHObjPtr allocas with GEP instructions
+ // that pull the EHObjPtr from the frame alloc structure
+ for (AllocaInst *EHObjPtr : HandlerEHObjPtrs) {
+ Value *EHData = EHDataMap[EHObjPtr->getParent()->getParent()];
+ Value *ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, 1);
+ EHObjPtr->replaceAllUsesWith(ElementPtr);
+ EHObjPtr->removeFromParent();
+ ElementPtr->takeName(EHObjPtr);
+ delete EHObjPtr;
+ }
+
+ // Finally, replace all of the temporary allocas for frame variables used in
+ // the outlined handlers and the original frame allocas with GEP instructions
+ // that get the equivalent pointer from the frame allocation struct.
+ for (auto &VarInfoEntry : FrameVarInfo) {
+ AllocaInst *ParentAlloca = VarInfoEntry.first;
+ HandlerAllocas &AllocaInfo = VarInfoEntry.second;
+ int Idx = AllocaInfo.ParentFrameAllocationIndex;
+
+ // If we have an index of -1 for this instruction, it means it isn't used
+ // outside of this handler. In that case, we just keep the "temporary"
+ // alloca in the handler and erase the original alloca from the parent.
+ if (Idx == -1) {
+ ParentAlloca->eraseFromParent();
+ } else {
+ // Otherwise, we replace the parent alloca and all outlined allocas
+ // which map to it with GEP instructions.
+
+ // First replace the original alloca.
+ Builder.SetInsertPoint(ParentAlloca);
+ Builder.SetCurrentDebugLocation(ParentAlloca->getDebugLoc());
+ Value *ElementPtr =
+ Builder.CreateConstInBoundsGEP2_32(FrameEHData, 0, Idx);
+ ParentAlloca->replaceAllUsesWith(ElementPtr);
+ ParentAlloca->removeFromParent();
+ ElementPtr->takeName(ParentAlloca);
+ delete ParentAlloca;
+
+ // Next replace all outlined allocas that are mapped to it.
+ for (AllocaInst *TempAlloca : AllocaInfo.Allocas) {
+ Value *EHData = EHDataMap[TempAlloca->getParent()->getParent()];
+ // FIXME: Sink this GEP into the blocks where it is used.
+ Builder.SetInsertPoint(TempAlloca);
+ Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
+ ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, Idx);
+ TempAlloca->replaceAllUsesWith(ElementPtr);
+ TempAlloca->removeFromParent();
+ ElementPtr->takeName(TempAlloca);
+ delete TempAlloca;
+ }
+ } // end else of if (Idx == -1)
+ } // End for each FrameVarInfo entry.
+
+ return HandlersOutlined;
+}
+
+bool WinEHPrepare::outlineCatchHandler(Function *SrcFn, Constant *SelectorType,
+ LandingPadInst *LPad, CallInst *&EHAlloc,
+ AllocaInst *&EHObjPtr,
+ 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);
+ FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
+ Function *CatchHandler = Function::Create(
+ FnType, GlobalVariable::ExternalLinkage, SrcFn->getName() + ".catch", M);
+
+ // Generate a standard prolog to setup the frame recovery structure.
+ IRBuilder<> Builder(Context);
+ BasicBlock *Entry = BasicBlock::Create(Context, "catch.entry");
+ CatchHandler->getBasicBlockList().push_front(Entry);
+ Builder.SetInsertPoint(Entry);
+ Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
+
+ // The outlined handler will be called with the parent's frame pointer as
+ // its second argument. To enable the handler to access variables from
+ // the parent frame, we use that pointer to get locate a special block
+ // of memory that was allocated using llvm.eh.allocateframe for this
+ // purpose. During the outlining process we will determine which frame
+ // variables are used in handlers and create a structure that maps these
+ // variables into the frame allocation block.
+ //
+ // The frame allocation block also contains an exception state variable
+ // used by the runtime and a pointer to the exception object pointer
+ // which will be filled in by the runtime for use in the handler.
+ Function *RecoverFrameFn =
+ Intrinsic::getDeclaration(M, Intrinsic::framerecover);
+ Value *RecoverArgs[] = {Builder.CreateBitCast(SrcFn, Int8PtrType, ""),
+ &(CatchHandler->getArgumentList().back())};
+ EHAlloc = Builder.CreateCall(RecoverFrameFn, RecoverArgs, "eh.alloc");
+
+ // This alloca is only temporary. We'll be replacing it once we know all the
+ // frame variables that need to go in the frame allocation structure.
+ EHObjPtr = Builder.CreateAlloca(Int8PtrType, 0, "eh.obj.ptr");
+
+ // This will give us a raw pointer to the exception object, which
+ // corresponds to the formal parameter of the catch statement. If the
+ // handler uses this object, we will generate code during the outlining
+ // process to cast the pointer to the appropriate type and deference it
+ // as necessary. The un-outlined landing pad code represents the
+ // exception object as the result of the llvm.eh.begincatch call.
+ Value *EHObj = Builder.CreateLoad(EHObjPtr, false, "eh.obj");
+
+ ValueToValueMapTy VMap;
+
+ // FIXME: Map other values referenced in the filter handler.
+
+ WinEHCatchDirector Director(LPad, CatchHandler, SelectorType, EHObj, VarInfo);
+
+ SmallVector<ReturnInst *, 8> Returns;
+ ClonedCodeInfo InlinedFunctionInfo;
+
+ BasicBlock::iterator II = LPad;
+
+ CloneAndPruneIntoFromInst(CatchHandler, SrcFn, ++II, VMap,
+ /*ModuleLevelChanges=*/false, Returns, "",
+ &InlinedFunctionInfo,
+ SrcFn->getParent()->getDataLayout(), &Director);
+
+ // 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();
+
+ return true;
+}
+
+CloningDirector::CloningAction WinEHCatchDirector::handleInstruction(
+ ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
+ // Intercept instructions which extract values from the landing pad aggregate.
+ if (auto *Extract = dyn_cast<ExtractValueInst>(Inst)) {
+ if (Extract->getAggregateOperand() == LPI) {
+ assert(Extract->getNumIndices() == 1 &&
+ "Unexpected operation: extracting both landing pad values");
+ assert((*(Extract->idx_begin()) == 0 || *(Extract->idx_begin()) == 1) &&
+ "Unexpected operation: extracting an unknown landing pad element");
+
+ if (*(Extract->idx_begin()) == 0) {
+ // Element 0 doesn't directly corresponds to anything in the WinEH
+ // scheme.
+ // It will be stored to a memory location, then later loaded and finally
+ // the loaded value will be used as the argument to an
+ // llvm.eh.begincatch
+ // call. We're tracking it here so that we can skip the store and load.
+ ExtractedEHPtr = Inst;
+ } else {
+ // Element 1 corresponds to the filter selector. We'll map it to 1 for
+ // matching purposes, but it will also probably be stored to memory and
+ // reloaded, so we need to track the instuction so that we can map the
+ // loaded value too.
+ VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
+ ExtractedSelector = Inst;
+ }
+
+ // Tell the caller not to clone this instruction.
+ return CloningDirector::SkipInstruction;
+ }
+ // Other extract value instructions just get cloned.
+ return CloningDirector::CloneInstruction;
+ }
+
+ if (auto *Store = dyn_cast<StoreInst>(Inst)) {
+ // Look for and suppress stores of the extracted landingpad values.
+ const Value *StoredValue = Store->getValueOperand();
+ if (StoredValue == ExtractedEHPtr) {
+ EHPtrStoreAddr = Store->getPointerOperand();
+ return CloningDirector::SkipInstruction;
+ }
+ if (StoredValue == ExtractedSelector) {
+ SelectorStoreAddr = Store->getPointerOperand();
+ return CloningDirector::SkipInstruction;
+ }
+
+ // Any other store just gets cloned.
+ return CloningDirector::CloneInstruction;
+ }
+
+ if (auto *Load = dyn_cast<LoadInst>(Inst)) {
+ // Look for loads of (previously suppressed) landingpad values.
+ // The EHPtr load can be ignored (it should only be used as
+ // an argument to llvm.eh.begincatch), but the selector value
+ // needs to be mapped to a constant value of 1 to be used to
+ // simplify the branching to always flow to the current handler.
+ const Value *LoadAddr = Load->getPointerOperand();
+ if (LoadAddr == EHPtrStoreAddr) {
+ VMap[Inst] = UndefValue::get(Int8PtrType);
+ return CloningDirector::SkipInstruction;
+ }
+ if (LoadAddr == SelectorStoreAddr) {
+ VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
+ return CloningDirector::SkipInstruction;
+ }
+
+ // Any other loads just get cloned.
+ return CloningDirector::CloneInstruction;
+ }
+
+ if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) {
+ // The argument to the call is some form of the first element of the
+ // landingpad aggregate value, but that doesn't matter. It isn't used
+ // here.
+ // The return value of this instruction, however, is used to access the
+ // EH object pointer. We have generated an instruction to get that value
+ // from the EH alloc block, so we can just map to that here.
+ VMap[Inst] = EHObj;
+ return CloningDirector::SkipInstruction;
+ }
+ if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) {
+ auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
+ // It might be interesting to track whether or not we are inside a catch
+ // function, but that might make the algorithm more brittle than it needs
+ // to be.
+
+ // The end catch call can occur in one of two places: either in a
+ // landingpad
+ // block that is part of the catch handlers exception mechanism, or at the
+ // end of the catch block. If it occurs in a landing pad, we must skip it
+ // and continue so that the landing pad gets cloned.
+ // FIXME: This case isn't fully supported yet and shouldn't turn up in any
+ // of the test cases until it is.
+ if (IntrinCall->getParent()->isLandingPad())
+ return CloningDirector::SkipInstruction;
+
+ // If an end catch occurs anywhere else the next instruction should be an
+ // unconditional branch instruction that we want to replace with a return
+ // to the the address of the branch target.
+ const BasicBlock *EndCatchBB = IntrinCall->getParent();
+ const TerminatorInst *Terminator = EndCatchBB->getTerminator();
+ const BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
+ assert(Branch && Branch->isUnconditional());
+ assert(std::next(BasicBlock::const_iterator(IntrinCall)) ==
+ BasicBlock::const_iterator(Branch));
+
+ ReturnInst::Create(NewBB->getContext(),
+ BlockAddress::get(Branch->getSuccessor(0)), NewBB);
+
+ // We just added a terminator to the cloned block.
+ // Tell the caller to stop processing the current basic block so that
+ // the branch instruction will be skipped.
+ return CloningDirector::StopCloningBB;
+ }
+ if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) {
+ auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
+ Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
+ // This causes a replacement that will collapse the landing pad CFG based
+ // on the filter function we intend to match.
+ if (Selector == CurrentSelector)
+ VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
+ else
+ VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
+ // Tell the caller not to clone this instruction.
+ return CloningDirector::SkipInstruction;
+ }
+
+ // Continue with the default cloning behavior.
+ return CloningDirector::CloneInstruction;
+}
+
+WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
+ Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
+ : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
+ Builder.SetInsertPoint(&OutlinedFn->getEntryBlock());
+ // FIXME: Do something with the FrameVarMapped so that it is shared across the
+ // function.
+}
+
+Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
+ // If we're asked to materialize an alloca variable, we temporarily
+ // create a matching alloca in the outlined function. When all the
+ // outlining is complete, we'll collect these into a structure and
+ // replace these temporary allocas with GEPs referencing the frame
+ // allocation block.
+ if (auto *AV = dyn_cast<AllocaInst>(V)) {
+ AllocaInst *NewAlloca = Builder.CreateAlloca(
+ AV->getAllocatedType(), AV->getArraySize(), AV->getName());
+ FrameVarInfo[AV].Allocas.push_back(NewAlloca);
+ return NewAlloca;
+ }
+
+// FIXME: Do PHI nodes need special handling?
+
+// FIXME: Are there other cases we can handle better? GEP, ExtractValue, etc.
+
+// FIXME: This doesn't work during cloning because it finds an instruction
+// in the use list that isn't yet part of a basic block.
+#if 0
+ // If we're asked to remap some other instruction, we'll need to
+ // spill it to an alloca variable in the parent function and add a
+ // temporary alloca in the outlined function to be processed as
+ // described above.
+ Instruction *Inst = dyn_cast<Instruction>(V);
+ if (Inst) {
+ AllocaInst *Spill = DemoteRegToStack(*Inst, true);
+ AllocaInst *NewAlloca = Builder.CreateAlloca(Spill->getAllocatedType(),
+ Spill->getArraySize());
+ FrameVarMap[AV] = NewAlloca;
+ return NewAlloca;
+ }
+#endif
+
+ return nullptr;
+}
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