forked from OSchip/llvm-project
2857 lines
115 KiB
C++
2857 lines
115 KiB
C++
//===-- WinEHPrepare - Prepare exception handling for code generation ---===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass lowers LLVM IR exception handling into something closer to what the
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// backend wants for functions using a personality function from a runtime
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// provided by MSVC. Functions with other personality functions are left alone
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// and may be prepared by other passes. In particular, all supported MSVC
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// personality functions require cleanup code to be outlined, and the C++
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// personality requires catch handler code to be outlined.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/ADT/MapVector.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/SetVector.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/ADT/TinyPtrVector.h"
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#include "llvm/Analysis/LibCallSemantics.h"
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#include "llvm/CodeGen/WinEHFuncInfo.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/Module.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Cloning.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/PromoteMemToReg.h"
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#include <memory>
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using namespace llvm;
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using namespace llvm::PatternMatch;
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#define DEBUG_TYPE "winehprepare"
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namespace {
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// This map is used to model frame variable usage during outlining, to
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// construct a structure type to hold the frame variables in a frame
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// allocation block, and to remap the frame variable allocas (including
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// spill locations as needed) to GEPs that get the variable from the
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// frame allocation structure.
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typedef MapVector<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap;
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// TinyPtrVector cannot hold nullptr, so we need our own sentinel that isn't
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// quite null.
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AllocaInst *getCatchObjectSentinel() {
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return static_cast<AllocaInst *>(nullptr) + 1;
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}
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typedef SmallSet<BasicBlock *, 4> VisitedBlockSet;
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class LandingPadActions;
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class LandingPadMap;
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typedef DenseMap<const BasicBlock *, CatchHandler *> CatchHandlerMapTy;
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typedef DenseMap<const BasicBlock *, CleanupHandler *> CleanupHandlerMapTy;
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class WinEHPrepare : public FunctionPass {
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public:
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static char ID; // Pass identification, replacement for typeid.
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WinEHPrepare(const TargetMachine *TM = nullptr)
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: FunctionPass(ID) {
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if (TM)
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TheTriple = Triple(TM->getTargetTriple());
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}
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bool runOnFunction(Function &Fn) override;
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bool doFinalization(Module &M) override;
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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const char *getPassName() const override {
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return "Windows exception handling preparation";
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}
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private:
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bool prepareExceptionHandlers(Function &F,
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SmallVectorImpl<LandingPadInst *> &LPads);
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void identifyEHBlocks(Function &F, SmallVectorImpl<LandingPadInst *> &LPads);
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void promoteLandingPadValues(LandingPadInst *LPad);
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void demoteValuesLiveAcrossHandlers(Function &F,
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SmallVectorImpl<LandingPadInst *> &LPads);
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void findSEHEHReturnPoints(Function &F,
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SetVector<BasicBlock *> &EHReturnBlocks);
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void findCXXEHReturnPoints(Function &F,
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SetVector<BasicBlock *> &EHReturnBlocks);
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void getPossibleReturnTargets(Function *ParentF, Function *HandlerF,
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SetVector<BasicBlock*> &Targets);
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void completeNestedLandingPad(Function *ParentFn,
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LandingPadInst *OutlinedLPad,
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const LandingPadInst *OriginalLPad,
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FrameVarInfoMap &VarInfo);
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Function *createHandlerFunc(Type *RetTy, const Twine &Name, Module *M,
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Value *&ParentFP);
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bool outlineHandler(ActionHandler *Action, Function *SrcFn,
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LandingPadInst *LPad, BasicBlock *StartBB,
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FrameVarInfoMap &VarInfo);
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void addStubInvokeToHandlerIfNeeded(Function *Handler, Value *PersonalityFn);
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void mapLandingPadBlocks(LandingPadInst *LPad, LandingPadActions &Actions);
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CatchHandler *findCatchHandler(BasicBlock *BB, BasicBlock *&NextBB,
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VisitedBlockSet &VisitedBlocks);
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void findCleanupHandlers(LandingPadActions &Actions, BasicBlock *StartBB,
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BasicBlock *EndBB);
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void processSEHCatchHandler(CatchHandler *Handler, BasicBlock *StartBB);
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Triple TheTriple;
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// All fields are reset by runOnFunction.
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DominatorTree *DT = nullptr;
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EHPersonality Personality = EHPersonality::Unknown;
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CatchHandlerMapTy CatchHandlerMap;
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CleanupHandlerMapTy CleanupHandlerMap;
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DenseMap<const LandingPadInst *, LandingPadMap> LPadMaps;
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SmallPtrSet<BasicBlock *, 4> NormalBlocks;
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SmallPtrSet<BasicBlock *, 4> EHBlocks;
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SetVector<BasicBlock *> EHReturnBlocks;
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// This maps landing pad instructions found in outlined handlers to
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// the landing pad instruction in the parent function from which they
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// were cloned. The cloned/nested landing pad is used as the key
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// because the landing pad may be cloned into multiple handlers.
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// This map will be used to add the llvm.eh.actions call to the nested
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// landing pads after all handlers have been outlined.
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DenseMap<LandingPadInst *, const LandingPadInst *> NestedLPtoOriginalLP;
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// This maps blocks in the parent function which are destinations of
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// catch handlers to cloned blocks in (other) outlined handlers. This
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// handles the case where a nested landing pads has a catch handler that
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// returns to a handler function rather than the parent function.
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// The original block is used as the key here because there should only
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// ever be one handler function from which the cloned block is not pruned.
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// The original block will be pruned from the parent function after all
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// handlers have been outlined. This map will be used to adjust the
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// return instructions of handlers which return to the block that was
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// outlined into a handler. This is done after all handlers have been
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// outlined but before the outlined code is pruned from the parent function.
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DenseMap<const BasicBlock *, BasicBlock *> LPadTargetBlocks;
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// Map from outlined handler to call to llvm.frameaddress(1). Only used for
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// 32-bit EH.
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DenseMap<Function *, Value *> HandlerToParentFP;
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AllocaInst *SEHExceptionCodeSlot = nullptr;
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};
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class WinEHFrameVariableMaterializer : public ValueMaterializer {
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public:
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WinEHFrameVariableMaterializer(Function *OutlinedFn, Value *ParentFP,
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FrameVarInfoMap &FrameVarInfo);
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~WinEHFrameVariableMaterializer() override {}
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Value *materializeValueFor(Value *V) override;
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void escapeCatchObject(Value *V);
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private:
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FrameVarInfoMap &FrameVarInfo;
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IRBuilder<> Builder;
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};
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class LandingPadMap {
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public:
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LandingPadMap() : OriginLPad(nullptr) {}
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void mapLandingPad(const LandingPadInst *LPad);
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bool isInitialized() { return OriginLPad != nullptr; }
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bool isOriginLandingPadBlock(const BasicBlock *BB) const;
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bool isLandingPadSpecificInst(const Instruction *Inst) const;
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void remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
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Value *SelectorValue) const;
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private:
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const LandingPadInst *OriginLPad;
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// We will normally only see one of each of these instructions, but
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// if more than one occurs for some reason we can handle that.
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TinyPtrVector<const ExtractValueInst *> ExtractedEHPtrs;
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TinyPtrVector<const ExtractValueInst *> ExtractedSelectors;
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};
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class WinEHCloningDirectorBase : public CloningDirector {
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public:
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WinEHCloningDirectorBase(Function *HandlerFn, Value *ParentFP,
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FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
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: Materializer(HandlerFn, ParentFP, VarInfo),
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SelectorIDType(Type::getInt32Ty(HandlerFn->getContext())),
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Int8PtrType(Type::getInt8PtrTy(HandlerFn->getContext())),
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LPadMap(LPadMap), ParentFP(ParentFP) {}
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CloningAction handleInstruction(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) override;
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virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
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const IndirectBrInst *IBr,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleInvoke(ValueToValueMapTy &VMap,
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const InvokeInst *Invoke,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleResume(ValueToValueMapTy &VMap,
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const ResumeInst *Resume,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleCompare(ValueToValueMapTy &VMap,
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const CmpInst *Compare,
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BasicBlock *NewBB) = 0;
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virtual CloningAction handleLandingPad(ValueToValueMapTy &VMap,
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const LandingPadInst *LPad,
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BasicBlock *NewBB) = 0;
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ValueMaterializer *getValueMaterializer() override { return &Materializer; }
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protected:
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WinEHFrameVariableMaterializer Materializer;
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Type *SelectorIDType;
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Type *Int8PtrType;
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LandingPadMap &LPadMap;
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/// The value representing the parent frame pointer.
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Value *ParentFP;
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};
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class WinEHCatchDirector : public WinEHCloningDirectorBase {
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public:
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WinEHCatchDirector(
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Function *CatchFn, Value *ParentFP, Value *Selector,
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FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap,
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DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads,
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DominatorTree *DT, SmallPtrSetImpl<BasicBlock *> &EHBlocks)
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: WinEHCloningDirectorBase(CatchFn, ParentFP, VarInfo, LPadMap),
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CurrentSelector(Selector->stripPointerCasts()),
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ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads),
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DT(DT), EHBlocks(EHBlocks) {}
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CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
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const IndirectBrInst *IBr,
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BasicBlock *NewBB) override;
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CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
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BasicBlock *NewBB) override;
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CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
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BasicBlock *NewBB) override;
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CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare,
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BasicBlock *NewBB) override;
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CloningAction handleLandingPad(ValueToValueMapTy &VMap,
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const LandingPadInst *LPad,
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BasicBlock *NewBB) override;
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Value *getExceptionVar() { return ExceptionObjectVar; }
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TinyPtrVector<BasicBlock *> &getReturnTargets() { return ReturnTargets; }
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private:
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Value *CurrentSelector;
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Value *ExceptionObjectVar;
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TinyPtrVector<BasicBlock *> ReturnTargets;
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// This will be a reference to the field of the same name in the WinEHPrepare
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// object which instantiates this WinEHCatchDirector object.
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DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPtoOriginalLP;
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DominatorTree *DT;
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SmallPtrSetImpl<BasicBlock *> &EHBlocks;
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};
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class WinEHCleanupDirector : public WinEHCloningDirectorBase {
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public:
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WinEHCleanupDirector(Function *CleanupFn, Value *ParentFP,
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FrameVarInfoMap &VarInfo, LandingPadMap &LPadMap)
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: WinEHCloningDirectorBase(CleanupFn, ParentFP, VarInfo,
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LPadMap) {}
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CloningAction handleBeginCatch(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleTypeIdFor(ValueToValueMapTy &VMap,
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const Instruction *Inst,
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BasicBlock *NewBB) override;
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CloningAction handleIndirectBr(ValueToValueMapTy &VMap,
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const IndirectBrInst *IBr,
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BasicBlock *NewBB) override;
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CloningAction handleInvoke(ValueToValueMapTy &VMap, const InvokeInst *Invoke,
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BasicBlock *NewBB) override;
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CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume,
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BasicBlock *NewBB) override;
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CloningAction handleCompare(ValueToValueMapTy &VMap, const CmpInst *Compare,
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BasicBlock *NewBB) override;
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CloningAction handleLandingPad(ValueToValueMapTy &VMap,
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const LandingPadInst *LPad,
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BasicBlock *NewBB) override;
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};
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class LandingPadActions {
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public:
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LandingPadActions() : HasCleanupHandlers(false) {}
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void insertCatchHandler(CatchHandler *Action) { Actions.push_back(Action); }
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void insertCleanupHandler(CleanupHandler *Action) {
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Actions.push_back(Action);
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HasCleanupHandlers = true;
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}
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bool includesCleanup() const { return HasCleanupHandlers; }
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SmallVectorImpl<ActionHandler *> &actions() { return Actions; }
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SmallVectorImpl<ActionHandler *>::iterator begin() { return Actions.begin(); }
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SmallVectorImpl<ActionHandler *>::iterator end() { return Actions.end(); }
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private:
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// Note that this class does not own the ActionHandler objects in this vector.
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// The ActionHandlers are owned by the CatchHandlerMap and CleanupHandlerMap
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// in the WinEHPrepare class.
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SmallVector<ActionHandler *, 4> Actions;
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bool HasCleanupHandlers;
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};
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} // end anonymous namespace
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char WinEHPrepare::ID = 0;
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INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions",
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false, false)
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FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) {
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return new WinEHPrepare(TM);
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}
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bool WinEHPrepare::runOnFunction(Function &Fn) {
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// No need to prepare outlined handlers.
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if (Fn.hasFnAttribute("wineh-parent"))
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return false;
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SmallVector<LandingPadInst *, 4> LPads;
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SmallVector<ResumeInst *, 4> Resumes;
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for (BasicBlock &BB : Fn) {
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if (auto *LP = BB.getLandingPadInst())
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LPads.push_back(LP);
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if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator()))
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Resumes.push_back(Resume);
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}
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// No need to prepare functions that lack landing pads.
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if (LPads.empty())
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return false;
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// Classify the personality to see what kind of preparation we need.
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Personality = classifyEHPersonality(LPads.back()->getPersonalityFn());
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// Do nothing if this is not an MSVC personality.
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if (!isMSVCEHPersonality(Personality))
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return false;
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DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
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// If there were any landing pads, prepareExceptionHandlers will make changes.
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prepareExceptionHandlers(Fn, LPads);
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return true;
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}
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bool WinEHPrepare::doFinalization(Module &M) { return false; }
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void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const {
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AU.addRequired<DominatorTreeWrapperPass>();
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}
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static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
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Constant *&Selector, BasicBlock *&NextBB);
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// Finds blocks reachable from the starting set Worklist. Does not follow unwind
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// edges or blocks listed in StopPoints.
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static void findReachableBlocks(SmallPtrSetImpl<BasicBlock *> &ReachableBBs,
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SetVector<BasicBlock *> &Worklist,
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const SetVector<BasicBlock *> *StopPoints) {
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while (!Worklist.empty()) {
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BasicBlock *BB = Worklist.pop_back_val();
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// Don't cross blocks that we should stop at.
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if (StopPoints && StopPoints->count(BB))
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continue;
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if (!ReachableBBs.insert(BB).second)
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continue; // Already visited.
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// Don't follow unwind edges of invokes.
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if (auto *II = dyn_cast<InvokeInst>(BB->getTerminator())) {
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Worklist.insert(II->getNormalDest());
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continue;
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}
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// Otherwise, follow all successors.
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Worklist.insert(succ_begin(BB), succ_end(BB));
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}
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}
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// Attempt to find an instruction where a block can be split before
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// a call to llvm.eh.begincatch and its operands. If the block
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// begins with the begincatch call or one of its adjacent operands
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// the block will not be split.
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static Instruction *findBeginCatchSplitPoint(BasicBlock *BB,
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IntrinsicInst *II) {
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// If the begincatch call is already the first instruction in the block,
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// don't split.
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Instruction *FirstNonPHI = BB->getFirstNonPHI();
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if (II == FirstNonPHI)
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return nullptr;
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// If either operand is in the same basic block as the instruction and
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// isn't used by another instruction before the begincatch call, include it
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// in the split block.
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auto *Op0 = dyn_cast<Instruction>(II->getOperand(0));
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auto *Op1 = dyn_cast<Instruction>(II->getOperand(1));
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Instruction *I = II->getPrevNode();
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Instruction *LastI = II;
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while (I == Op0 || I == Op1) {
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// If the block begins with one of the operands and there are no other
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// instructions between the operand and the begincatch call, don't split.
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if (I == FirstNonPHI)
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return nullptr;
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LastI = I;
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I = I->getPrevNode();
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}
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// If there is at least one instruction in the block before the begincatch
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// call and its operands, split the block at either the begincatch or
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// its operand.
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return LastI;
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}
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/// Find all points where exceptional control rejoins normal control flow via
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/// llvm.eh.endcatch. Add them to the normal bb reachability worklist.
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void WinEHPrepare::findCXXEHReturnPoints(
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Function &F, SetVector<BasicBlock *> &EHReturnBlocks) {
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for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
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BasicBlock *BB = BBI;
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for (Instruction &I : *BB) {
|
|
if (match(&I, m_Intrinsic<Intrinsic::eh_begincatch>())) {
|
|
Instruction *SplitPt =
|
|
findBeginCatchSplitPoint(BB, cast<IntrinsicInst>(&I));
|
|
if (SplitPt) {
|
|
// Split the block before the llvm.eh.begincatch call to allow
|
|
// cleanup and catch code to be distinguished later.
|
|
// Do not update BBI because we still need to process the
|
|
// portion of the block that we are splitting off.
|
|
SplitBlock(BB, SplitPt, DT);
|
|
break;
|
|
}
|
|
}
|
|
if (match(&I, m_Intrinsic<Intrinsic::eh_endcatch>())) {
|
|
// Split the block after the call to llvm.eh.endcatch if there is
|
|
// anything other than an unconditional branch, or if the successor
|
|
// starts with a phi.
|
|
auto *Br = dyn_cast<BranchInst>(I.getNextNode());
|
|
if (!Br || !Br->isUnconditional() ||
|
|
isa<PHINode>(Br->getSuccessor(0)->begin())) {
|
|
DEBUG(dbgs() << "splitting block " << BB->getName()
|
|
<< " with llvm.eh.endcatch\n");
|
|
BBI = SplitBlock(BB, I.getNextNode(), DT);
|
|
}
|
|
// The next BB is normal control flow.
|
|
EHReturnBlocks.insert(BB->getTerminator()->getSuccessor(0));
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static bool isCatchAllLandingPad(const BasicBlock *BB) {
|
|
const LandingPadInst *LP = BB->getLandingPadInst();
|
|
if (!LP)
|
|
return false;
|
|
unsigned N = LP->getNumClauses();
|
|
return (N > 0 && LP->isCatch(N - 1) &&
|
|
isa<ConstantPointerNull>(LP->getClause(N - 1)));
|
|
}
|
|
|
|
/// Find all points where exceptions control rejoins normal control flow via
|
|
/// selector dispatch.
|
|
void WinEHPrepare::findSEHEHReturnPoints(
|
|
Function &F, SetVector<BasicBlock *> &EHReturnBlocks) {
|
|
for (auto BBI = F.begin(), BBE = F.end(); BBI != BBE; ++BBI) {
|
|
BasicBlock *BB = BBI;
|
|
// If the landingpad is a catch-all, treat the whole lpad as if it is
|
|
// reachable from normal control flow.
|
|
// FIXME: This is imprecise. We need a better way of identifying where a
|
|
// catch-all starts and cleanups stop. As far as LLVM is concerned, there
|
|
// is no difference.
|
|
if (isCatchAllLandingPad(BB)) {
|
|
EHReturnBlocks.insert(BB);
|
|
continue;
|
|
}
|
|
|
|
BasicBlock *CatchHandler;
|
|
BasicBlock *NextBB;
|
|
Constant *Selector;
|
|
if (isSelectorDispatch(BB, CatchHandler, Selector, NextBB)) {
|
|
// Split the edge if there is a phi node. Returning from EH to a phi node
|
|
// is just as impossible as having a phi after an indirectbr.
|
|
if (isa<PHINode>(CatchHandler->begin())) {
|
|
DEBUG(dbgs() << "splitting EH return edge from " << BB->getName()
|
|
<< " to " << CatchHandler->getName() << '\n');
|
|
BBI = CatchHandler = SplitCriticalEdge(
|
|
BB, std::find(succ_begin(BB), succ_end(BB), CatchHandler));
|
|
}
|
|
EHReturnBlocks.insert(CatchHandler);
|
|
}
|
|
}
|
|
}
|
|
|
|
void WinEHPrepare::identifyEHBlocks(Function &F,
|
|
SmallVectorImpl<LandingPadInst *> &LPads) {
|
|
DEBUG(dbgs() << "Demoting values live across exception handlers in function "
|
|
<< F.getName() << '\n');
|
|
|
|
// Build a set of all non-exceptional blocks and exceptional blocks.
|
|
// - Non-exceptional blocks are blocks reachable from the entry block while
|
|
// not following invoke unwind edges.
|
|
// - Exceptional blocks are blocks reachable from landingpads. Analysis does
|
|
// not follow llvm.eh.endcatch blocks, which mark a transition from
|
|
// exceptional to normal control.
|
|
|
|
if (Personality == EHPersonality::MSVC_CXX)
|
|
findCXXEHReturnPoints(F, EHReturnBlocks);
|
|
else
|
|
findSEHEHReturnPoints(F, EHReturnBlocks);
|
|
|
|
DEBUG({
|
|
dbgs() << "identified the following blocks as EH return points:\n";
|
|
for (BasicBlock *BB : EHReturnBlocks)
|
|
dbgs() << " " << BB->getName() << '\n';
|
|
});
|
|
|
|
// Join points should not have phis at this point, unless they are a
|
|
// landingpad, in which case we will demote their phis later.
|
|
#ifndef NDEBUG
|
|
for (BasicBlock *BB : EHReturnBlocks)
|
|
assert((BB->isLandingPad() || !isa<PHINode>(BB->begin())) &&
|
|
"non-lpad EH return block has phi");
|
|
#endif
|
|
|
|
// Normal blocks are the blocks reachable from the entry block and all EH
|
|
// return points.
|
|
SetVector<BasicBlock *> Worklist;
|
|
Worklist = EHReturnBlocks;
|
|
Worklist.insert(&F.getEntryBlock());
|
|
findReachableBlocks(NormalBlocks, Worklist, nullptr);
|
|
DEBUG({
|
|
dbgs() << "marked the following blocks as normal:\n";
|
|
for (BasicBlock *BB : NormalBlocks)
|
|
dbgs() << " " << BB->getName() << '\n';
|
|
});
|
|
|
|
// Exceptional blocks are the blocks reachable from landingpads that don't
|
|
// cross EH return points.
|
|
Worklist.clear();
|
|
for (auto *LPI : LPads)
|
|
Worklist.insert(LPI->getParent());
|
|
findReachableBlocks(EHBlocks, Worklist, &EHReturnBlocks);
|
|
DEBUG({
|
|
dbgs() << "marked the following blocks as exceptional:\n";
|
|
for (BasicBlock *BB : EHBlocks)
|
|
dbgs() << " " << BB->getName() << '\n';
|
|
});
|
|
|
|
}
|
|
|
|
/// Ensure that all values live into and out of exception handlers are stored
|
|
/// in memory.
|
|
/// FIXME: This falls down when values are defined in one handler and live into
|
|
/// another handler. For example, a cleanup defines a value used only by a
|
|
/// catch handler.
|
|
void WinEHPrepare::demoteValuesLiveAcrossHandlers(
|
|
Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
|
|
DEBUG(dbgs() << "Demoting values live across exception handlers in function "
|
|
<< F.getName() << '\n');
|
|
|
|
// identifyEHBlocks() should have been called before this function.
|
|
assert(!NormalBlocks.empty());
|
|
|
|
SetVector<Argument *> ArgsToDemote;
|
|
SetVector<Instruction *> InstrsToDemote;
|
|
for (BasicBlock &BB : F) {
|
|
bool IsNormalBB = NormalBlocks.count(&BB);
|
|
bool IsEHBB = EHBlocks.count(&BB);
|
|
if (!IsNormalBB && !IsEHBB)
|
|
continue; // Blocks that are neither normal nor EH are unreachable.
|
|
for (Instruction &I : BB) {
|
|
for (Value *Op : I.operands()) {
|
|
// Don't demote static allocas, constants, and labels.
|
|
if (isa<Constant>(Op) || isa<BasicBlock>(Op) || isa<InlineAsm>(Op))
|
|
continue;
|
|
auto *AI = dyn_cast<AllocaInst>(Op);
|
|
if (AI && AI->isStaticAlloca())
|
|
continue;
|
|
|
|
if (auto *Arg = dyn_cast<Argument>(Op)) {
|
|
if (IsEHBB) {
|
|
DEBUG(dbgs() << "Demoting argument " << *Arg
|
|
<< " used by EH instr: " << I << "\n");
|
|
ArgsToDemote.insert(Arg);
|
|
}
|
|
continue;
|
|
}
|
|
|
|
auto *OpI = cast<Instruction>(Op);
|
|
BasicBlock *OpBB = OpI->getParent();
|
|
// If a value is produced and consumed in the same BB, we don't need to
|
|
// demote it.
|
|
if (OpBB == &BB)
|
|
continue;
|
|
bool IsOpNormalBB = NormalBlocks.count(OpBB);
|
|
bool IsOpEHBB = EHBlocks.count(OpBB);
|
|
if (IsNormalBB != IsOpNormalBB || IsEHBB != IsOpEHBB) {
|
|
DEBUG({
|
|
dbgs() << "Demoting instruction live in-out from EH:\n";
|
|
dbgs() << "Instr: " << *OpI << '\n';
|
|
dbgs() << "User: " << I << '\n';
|
|
});
|
|
InstrsToDemote.insert(OpI);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
// Demote values live into and out of handlers.
|
|
// FIXME: This demotion is inefficient. We should insert spills at the point
|
|
// of definition, insert one reload in each handler that uses the value, and
|
|
// insert reloads in the BB used to rejoin normal control flow.
|
|
Instruction *AllocaInsertPt = F.getEntryBlock().getFirstInsertionPt();
|
|
for (Instruction *I : InstrsToDemote)
|
|
DemoteRegToStack(*I, false, AllocaInsertPt);
|
|
|
|
// Demote arguments separately, and only for uses in EH blocks.
|
|
for (Argument *Arg : ArgsToDemote) {
|
|
auto *Slot = new AllocaInst(Arg->getType(), nullptr,
|
|
Arg->getName() + ".reg2mem", AllocaInsertPt);
|
|
SmallVector<User *, 4> Users(Arg->user_begin(), Arg->user_end());
|
|
for (User *U : Users) {
|
|
auto *I = dyn_cast<Instruction>(U);
|
|
if (I && EHBlocks.count(I->getParent())) {
|
|
auto *Reload = new LoadInst(Slot, Arg->getName() + ".reload", false, I);
|
|
U->replaceUsesOfWith(Arg, Reload);
|
|
}
|
|
}
|
|
new StoreInst(Arg, Slot, AllocaInsertPt);
|
|
}
|
|
|
|
// Demote landingpad phis, as the landingpad will be removed from the machine
|
|
// CFG.
|
|
for (LandingPadInst *LPI : LPads) {
|
|
BasicBlock *BB = LPI->getParent();
|
|
while (auto *Phi = dyn_cast<PHINode>(BB->begin()))
|
|
DemotePHIToStack(Phi, AllocaInsertPt);
|
|
}
|
|
|
|
DEBUG(dbgs() << "Demoted " << InstrsToDemote.size() << " instructions and "
|
|
<< ArgsToDemote.size() << " arguments for WinEHPrepare\n\n");
|
|
}
|
|
|
|
bool WinEHPrepare::prepareExceptionHandlers(
|
|
Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
|
|
// Don't run on functions that are already prepared.
|
|
for (LandingPadInst *LPad : LPads) {
|
|
BasicBlock *LPadBB = LPad->getParent();
|
|
for (Instruction &Inst : *LPadBB)
|
|
if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>()))
|
|
return false;
|
|
}
|
|
|
|
identifyEHBlocks(F, LPads);
|
|
demoteValuesLiveAcrossHandlers(F, LPads);
|
|
|
|
// These containers are used to re-map frame variables that are used in
|
|
// outlined catch and cleanup handlers. They will be populated as the
|
|
// handlers are outlined.
|
|
FrameVarInfoMap FrameVarInfo;
|
|
|
|
bool HandlersOutlined = false;
|
|
|
|
Module *M = F.getParent();
|
|
LLVMContext &Context = M->getContext();
|
|
|
|
// Create a new function to receive the handler contents.
|
|
PointerType *Int8PtrType = Type::getInt8PtrTy(Context);
|
|
Type *Int32Type = Type::getInt32Ty(Context);
|
|
Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions);
|
|
|
|
if (isAsynchronousEHPersonality(Personality)) {
|
|
// FIXME: Switch the ehptr type to i32 and then switch this.
|
|
SEHExceptionCodeSlot =
|
|
new AllocaInst(Int8PtrType, nullptr, "seh_exception_code",
|
|
F.getEntryBlock().getFirstInsertionPt());
|
|
}
|
|
|
|
// In order to handle the case where one outlined catch handler returns
|
|
// to a block within another outlined catch handler that would otherwise
|
|
// be unreachable, we need to outline the nested landing pad before we
|
|
// outline the landing pad which encloses it.
|
|
if (!isAsynchronousEHPersonality(Personality))
|
|
std::sort(LPads.begin(), LPads.end(),
|
|
[this](LandingPadInst *const &L, LandingPadInst *const &R) {
|
|
return DT->properlyDominates(R->getParent(), L->getParent());
|
|
});
|
|
|
|
// This container stores the llvm.eh.recover and IndirectBr instructions
|
|
// that make up the body of each landing pad after it has been outlined.
|
|
// We need to defer the population of the target list for the indirectbr
|
|
// until all landing pads have been outlined so that we can handle the
|
|
// case of blocks in the target that are reached only from nested
|
|
// landing pads.
|
|
SmallVector<std::pair<CallInst*, IndirectBrInst *>, 4> LPadImpls;
|
|
|
|
for (LandingPadInst *LPad : LPads) {
|
|
// Look for evidence that this landingpad has already been processed.
|
|
bool LPadHasActionList = false;
|
|
BasicBlock *LPadBB = LPad->getParent();
|
|
for (Instruction &Inst : *LPadBB) {
|
|
if (match(&Inst, m_Intrinsic<Intrinsic::eh_actions>())) {
|
|
LPadHasActionList = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If we've already outlined the handlers for this landingpad,
|
|
// there's nothing more to do here.
|
|
if (LPadHasActionList)
|
|
continue;
|
|
|
|
// If either of the values in the aggregate returned by the landing pad is
|
|
// extracted and stored to memory, promote the stored value to a register.
|
|
promoteLandingPadValues(LPad);
|
|
|
|
LandingPadActions Actions;
|
|
mapLandingPadBlocks(LPad, Actions);
|
|
|
|
HandlersOutlined |= !Actions.actions().empty();
|
|
for (ActionHandler *Action : Actions) {
|
|
if (Action->hasBeenProcessed())
|
|
continue;
|
|
BasicBlock *StartBB = Action->getStartBlock();
|
|
|
|
// SEH doesn't do any outlining for catches. Instead, pass the handler
|
|
// basic block addr to llvm.eh.actions and list the block as a return
|
|
// target.
|
|
if (isAsynchronousEHPersonality(Personality)) {
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
processSEHCatchHandler(CatchAction, StartBB);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo);
|
|
}
|
|
|
|
// Split the block after the landingpad instruction so that it is just a
|
|
// call to llvm.eh.actions followed by indirectbr.
|
|
assert(!isa<PHINode>(LPadBB->begin()) && "lpad phi not removed");
|
|
SplitBlock(LPadBB, LPad->getNextNode(), DT);
|
|
// Erase the branch inserted by the split so we can insert indirectbr.
|
|
LPadBB->getTerminator()->eraseFromParent();
|
|
|
|
// Replace all extracted values with undef and ultimately replace the
|
|
// landingpad with undef.
|
|
SmallVector<Instruction *, 4> SEHCodeUses;
|
|
SmallVector<Instruction *, 4> EHUndefs;
|
|
for (User *U : LPad->users()) {
|
|
auto *E = dyn_cast<ExtractValueInst>(U);
|
|
if (!E)
|
|
continue;
|
|
assert(E->getNumIndices() == 1 &&
|
|
"Unexpected operation: extracting both landing pad values");
|
|
unsigned Idx = *E->idx_begin();
|
|
assert((Idx == 0 || Idx == 1) && "unexpected index");
|
|
if (Idx == 0 && isAsynchronousEHPersonality(Personality))
|
|
SEHCodeUses.push_back(E);
|
|
else
|
|
EHUndefs.push_back(E);
|
|
}
|
|
for (Instruction *E : EHUndefs) {
|
|
E->replaceAllUsesWith(UndefValue::get(E->getType()));
|
|
E->eraseFromParent();
|
|
}
|
|
LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
|
|
|
|
// Rewrite uses of the exception pointer to loads of an alloca.
|
|
for (Instruction *E : SEHCodeUses) {
|
|
SmallVector<Use *, 4> Uses;
|
|
for (Use &U : E->uses())
|
|
Uses.push_back(&U);
|
|
for (Use *U : Uses) {
|
|
auto *I = cast<Instruction>(U->getUser());
|
|
if (isa<ResumeInst>(I))
|
|
continue;
|
|
LoadInst *LI;
|
|
if (auto *Phi = dyn_cast<PHINode>(I))
|
|
LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false,
|
|
Phi->getIncomingBlock(*U));
|
|
else
|
|
LI = new LoadInst(SEHExceptionCodeSlot, "sehcode", false, I);
|
|
U->set(LI);
|
|
}
|
|
E->replaceAllUsesWith(UndefValue::get(E->getType()));
|
|
E->eraseFromParent();
|
|
}
|
|
|
|
// Add a call to describe the actions for this landing pad.
|
|
std::vector<Value *> ActionArgs;
|
|
for (ActionHandler *Action : Actions) {
|
|
// Action codes from docs are: 0 cleanup, 1 catch.
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
ActionArgs.push_back(ConstantInt::get(Int32Type, 1));
|
|
ActionArgs.push_back(CatchAction->getSelector());
|
|
// Find the frame escape index of the exception object alloca in the
|
|
// parent.
|
|
int FrameEscapeIdx = -1;
|
|
Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar());
|
|
if (EHObj && !isa<ConstantPointerNull>(EHObj)) {
|
|
auto I = FrameVarInfo.find(EHObj);
|
|
assert(I != FrameVarInfo.end() &&
|
|
"failed to map llvm.eh.begincatch var");
|
|
FrameEscapeIdx = std::distance(FrameVarInfo.begin(), I);
|
|
}
|
|
ActionArgs.push_back(ConstantInt::get(Int32Type, FrameEscapeIdx));
|
|
} else {
|
|
ActionArgs.push_back(ConstantInt::get(Int32Type, 0));
|
|
}
|
|
ActionArgs.push_back(Action->getHandlerBlockOrFunc());
|
|
}
|
|
CallInst *Recover =
|
|
CallInst::Create(ActionIntrin, ActionArgs, "recover", LPadBB);
|
|
|
|
SetVector<BasicBlock *> ReturnTargets;
|
|
for (ActionHandler *Action : Actions) {
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
const auto &CatchTargets = CatchAction->getReturnTargets();
|
|
ReturnTargets.insert(CatchTargets.begin(), CatchTargets.end());
|
|
}
|
|
}
|
|
IndirectBrInst *Branch =
|
|
IndirectBrInst::Create(Recover, ReturnTargets.size(), LPadBB);
|
|
for (BasicBlock *Target : ReturnTargets)
|
|
Branch->addDestination(Target);
|
|
|
|
if (!isAsynchronousEHPersonality(Personality)) {
|
|
// C++ EH must repopulate the targets later to handle the case of
|
|
// targets that are reached indirectly through nested landing pads.
|
|
LPadImpls.push_back(std::make_pair(Recover, Branch));
|
|
}
|
|
|
|
} // End for each landingpad
|
|
|
|
// 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();
|
|
|
|
// Update the indirectbr instructions' target lists if necessary.
|
|
SetVector<BasicBlock*> CheckedTargets;
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
|
|
for (auto &LPadImplPair : LPadImpls) {
|
|
IntrinsicInst *Recover = cast<IntrinsicInst>(LPadImplPair.first);
|
|
IndirectBrInst *Branch = LPadImplPair.second;
|
|
|
|
// Get a list of handlers called by
|
|
parseEHActions(Recover, ActionList);
|
|
|
|
// Add an indirect branch listing possible successors of the catch handlers.
|
|
SetVector<BasicBlock *> ReturnTargets;
|
|
for (const auto &Action : ActionList) {
|
|
if (auto *CA = dyn_cast<CatchHandler>(Action.get())) {
|
|
Function *Handler = cast<Function>(CA->getHandlerBlockOrFunc());
|
|
getPossibleReturnTargets(&F, Handler, ReturnTargets);
|
|
}
|
|
}
|
|
ActionList.clear();
|
|
// Clear any targets we already knew about.
|
|
for (unsigned int I = 0, E = Branch->getNumDestinations(); I < E; ++I) {
|
|
BasicBlock *KnownTarget = Branch->getDestination(I);
|
|
if (ReturnTargets.count(KnownTarget))
|
|
ReturnTargets.remove(KnownTarget);
|
|
}
|
|
for (BasicBlock *Target : ReturnTargets) {
|
|
Branch->addDestination(Target);
|
|
// The target may be a block that we excepted to get pruned.
|
|
// If it is, it may contain a call to llvm.eh.endcatch.
|
|
if (CheckedTargets.insert(Target)) {
|
|
// Earlier preparations guarantee that all calls to llvm.eh.endcatch
|
|
// will be followed by an unconditional branch.
|
|
auto *Br = dyn_cast<BranchInst>(Target->getTerminator());
|
|
if (Br && Br->isUnconditional() &&
|
|
Br != Target->getFirstNonPHIOrDbgOrLifetime()) {
|
|
Instruction *Prev = Br->getPrevNode();
|
|
if (match(cast<Value>(Prev), m_Intrinsic<Intrinsic::eh_endcatch>()))
|
|
Prev->eraseFromParent();
|
|
}
|
|
}
|
|
}
|
|
}
|
|
LPadImpls.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);
|
|
SmallVector<Value *, 8> AllocasToEscape;
|
|
|
|
// Scan the entry block for an existing call to llvm.frameescape. We need to
|
|
// keep escaping those objects.
|
|
for (Instruction &I : F.front()) {
|
|
auto *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (II && II->getIntrinsicID() == Intrinsic::frameescape) {
|
|
auto Args = II->arg_operands();
|
|
AllocasToEscape.append(Args.begin(), Args.end());
|
|
II->eraseFromParent();
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Finally, replace all of the temporary allocas for frame variables used in
|
|
// the outlined handlers with calls to llvm.framerecover.
|
|
for (auto &VarInfoEntry : FrameVarInfo) {
|
|
Value *ParentVal = VarInfoEntry.first;
|
|
TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
|
|
AllocaInst *ParentAlloca = cast<AllocaInst>(ParentVal);
|
|
|
|
// FIXME: We should try to sink unescaped allocas from the parent frame into
|
|
// the child frame. If the alloca is escaped, we have to use the lifetime
|
|
// markers to ensure that the alloca is only live within the child frame.
|
|
|
|
// Add this alloca to the list of things to escape.
|
|
AllocasToEscape.push_back(ParentAlloca);
|
|
|
|
// Next replace all outlined allocas that are mapped to it.
|
|
for (AllocaInst *TempAlloca : Allocas) {
|
|
if (TempAlloca == getCatchObjectSentinel())
|
|
continue; // Skip catch parameter sentinels.
|
|
Function *HandlerFn = TempAlloca->getParent()->getParent();
|
|
llvm::Value *FP = HandlerToParentFP[HandlerFn];
|
|
assert(FP);
|
|
|
|
// FIXME: Sink this framerecover into the blocks where it is used.
|
|
Builder.SetInsertPoint(TempAlloca);
|
|
Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
|
|
Value *RecoverArgs[] = {
|
|
Builder.CreateBitCast(&F, Int8PtrType, ""), FP,
|
|
llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
|
|
Instruction *RecoveredAlloca =
|
|
Builder.CreateCall(RecoverFrameFn, RecoverArgs);
|
|
|
|
// Add a pointer bitcast if the alloca wasn't an i8.
|
|
if (RecoveredAlloca->getType() != TempAlloca->getType()) {
|
|
RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8");
|
|
RecoveredAlloca = cast<Instruction>(
|
|
Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType()));
|
|
}
|
|
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);
|
|
|
|
if (SEHExceptionCodeSlot) {
|
|
if (SEHExceptionCodeSlot->hasNUses(0))
|
|
SEHExceptionCodeSlot->eraseFromParent();
|
|
else if (isAllocaPromotable(SEHExceptionCodeSlot))
|
|
PromoteMemToReg(SEHExceptionCodeSlot, *DT);
|
|
}
|
|
|
|
// Clean up the handler action maps we created for this function
|
|
DeleteContainerSeconds(CatchHandlerMap);
|
|
CatchHandlerMap.clear();
|
|
DeleteContainerSeconds(CleanupHandlerMap);
|
|
CleanupHandlerMap.clear();
|
|
HandlerToParentFP.clear();
|
|
DT = nullptr;
|
|
SEHExceptionCodeSlot = nullptr;
|
|
EHBlocks.clear();
|
|
NormalBlocks.clear();
|
|
EHReturnBlocks.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::getPossibleReturnTargets(Function *ParentF,
|
|
Function *HandlerF,
|
|
SetVector<BasicBlock*> &Targets) {
|
|
for (BasicBlock &BB : *HandlerF) {
|
|
// If the handler contains landing pads, check for any
|
|
// handlers that may return directly to a block in the
|
|
// parent function.
|
|
if (auto *LPI = BB.getLandingPadInst()) {
|
|
IntrinsicInst *Recover = cast<IntrinsicInst>(LPI->getNextNode());
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
|
|
parseEHActions(Recover, ActionList);
|
|
for (const auto &Action : ActionList) {
|
|
if (auto *CH = dyn_cast<CatchHandler>(Action.get())) {
|
|
Function *NestedF = cast<Function>(CH->getHandlerBlockOrFunc());
|
|
getPossibleReturnTargets(ParentF, NestedF, Targets);
|
|
}
|
|
}
|
|
}
|
|
|
|
auto *Ret = dyn_cast<ReturnInst>(BB.getTerminator());
|
|
if (!Ret)
|
|
continue;
|
|
|
|
// Handler functions must always return a block address.
|
|
BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
|
|
|
|
// If this is the handler for a nested landing pad, the
|
|
// return address may have been remapped to a block in the
|
|
// parent handler. We're not interested in those.
|
|
if (BA->getFunction() != ParentF)
|
|
continue;
|
|
|
|
Targets.insert(BA->getBasicBlock());
|
|
}
|
|
}
|
|
|
|
void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
|
|
LandingPadInst *OutlinedLPad,
|
|
const LandingPadInst *OriginalLPad,
|
|
FrameVarInfoMap &FrameVarInfo) {
|
|
// Get the nested block and erase the unreachable instruction that was
|
|
// temporarily inserted as its terminator.
|
|
LLVMContext &Context = ParentFn->getContext();
|
|
BasicBlock *OutlinedBB = OutlinedLPad->getParent();
|
|
// If the nested landing pad was outlined before the landing pad that enclosed
|
|
// it, it will already be in outlined form. In that case, we just need to see
|
|
// if the returns and the enclosing branch instruction need to be updated.
|
|
IndirectBrInst *Branch =
|
|
dyn_cast<IndirectBrInst>(OutlinedBB->getTerminator());
|
|
if (!Branch) {
|
|
// If the landing pad wasn't in outlined form, it should be a stub with
|
|
// an unreachable terminator.
|
|
assert(isa<UnreachableInst>(OutlinedBB->getTerminator()));
|
|
OutlinedBB->getTerminator()->eraseFromParent();
|
|
// That should leave OutlinedLPad as the last instruction in its block.
|
|
assert(&OutlinedBB->back() == OutlinedLPad);
|
|
}
|
|
|
|
// 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>()));
|
|
const IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover);
|
|
|
|
// Remap the return target in the nested handler.
|
|
SmallVector<BlockAddress *, 4> ActionTargets;
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
|
|
parseEHActions(EHActions, ActionList);
|
|
for (const auto &Action : ActionList) {
|
|
auto *Catch = dyn_cast<CatchHandler>(Action.get());
|
|
if (!Catch)
|
|
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 an outlined handler function.
|
|
if (!LPadTargetBlocks.count(BA->getBasicBlock()))
|
|
continue;
|
|
|
|
// If the return value is the address ofF a block that we
|
|
// previously outlined into the parent handler function, replace
|
|
// the return instruction and add the mapped target to the list
|
|
// of possible return addresses.
|
|
BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()];
|
|
assert(MappedBB->getParent() == OutlinedHandlerFn);
|
|
BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB);
|
|
Ret->eraseFromParent();
|
|
ReturnInst::Create(Context, NewBA, &NestedHandlerBB);
|
|
ActionTargets.push_back(NewBA);
|
|
}
|
|
}
|
|
ActionList.clear();
|
|
|
|
if (Branch) {
|
|
// If the landing pad was already in outlined form, just update its targets.
|
|
for (unsigned int I = Branch->getNumDestinations(); I > 0; --I)
|
|
Branch->removeDestination(I);
|
|
// Add the previously collected action targets.
|
|
for (auto *Target : ActionTargets)
|
|
Branch->addDestination(Target->getBasicBlock());
|
|
} else {
|
|
// If the landing pad was previously stubbed out, fill in its outlined form.
|
|
IntrinsicInst *NewEHActions = cast<IntrinsicInst>(EHActions->clone());
|
|
OutlinedBB->getInstList().push_back(NewEHActions);
|
|
|
|
// Insert an indirect branch into the outlined landing pad BB.
|
|
IndirectBrInst *IBr = IndirectBrInst::Create(NewEHActions, 0, OutlinedBB);
|
|
// Add the previously collected action targets.
|
|
for (auto *Target : ActionTargets)
|
|
IBr->addDestination(Target->getBasicBlock());
|
|
}
|
|
}
|
|
|
|
// This function examines a block to determine whether the block ends with a
|
|
// conditional branch to a catch handler based on a selector comparison.
|
|
// This function is used both by the WinEHPrepare::findSelectorComparison() and
|
|
// WinEHCleanupDirector::handleTypeIdFor().
|
|
static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
|
|
Constant *&Selector, BasicBlock *&NextBB) {
|
|
ICmpInst::Predicate Pred;
|
|
BasicBlock *TBB, *FBB;
|
|
Value *LHS, *RHS;
|
|
|
|
if (!match(BB->getTerminator(),
|
|
m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)), TBB, FBB)))
|
|
return false;
|
|
|
|
if (!match(LHS,
|
|
m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))) &&
|
|
!match(RHS, m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))))
|
|
return false;
|
|
|
|
if (Pred == CmpInst::ICMP_EQ) {
|
|
CatchHandler = TBB;
|
|
NextBB = FBB;
|
|
return true;
|
|
}
|
|
|
|
if (Pred == CmpInst::ICMP_NE) {
|
|
CatchHandler = FBB;
|
|
NextBB = TBB;
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static bool isCatchBlock(BasicBlock *BB) {
|
|
for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
|
|
II != IE; ++II) {
|
|
if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_begincatch>()))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static BasicBlock *createStubLandingPad(Function *Handler,
|
|
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);
|
|
// Insert a call to llvm.eh.actions so that we don't try to outline this lpad.
|
|
Function *ActionIntrin =
|
|
Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::eh_actions);
|
|
Builder.CreateCall(ActionIntrin, {}, "recover");
|
|
LPad->setCleanup(true);
|
|
Builder.CreateUnreachable();
|
|
return StubBB;
|
|
}
|
|
|
|
// Cycles through the blocks in an outlined handler function looking for an
|
|
// invoke instruction and inserts an invoke of llvm.donothing with an empty
|
|
// landing pad if none is found. The code that generates the .xdata tables for
|
|
// the handler needs at least one landing pad to identify the parent function's
|
|
// personality.
|
|
void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler,
|
|
Value *PersonalityFn) {
|
|
ReturnInst *Ret = nullptr;
|
|
UnreachableInst *Unreached = nullptr;
|
|
for (BasicBlock &BB : *Handler) {
|
|
TerminatorInst *Terminator = BB.getTerminator();
|
|
// If we find an invoke, there is nothing to be done.
|
|
auto *II = dyn_cast<InvokeInst>(Terminator);
|
|
if (II)
|
|
return;
|
|
// If we've already recorded a return instruction, keep looking for invokes.
|
|
if (!Ret)
|
|
Ret = dyn_cast<ReturnInst>(Terminator);
|
|
// If we haven't recorded an unreachable instruction, try this terminator.
|
|
if (!Unreached)
|
|
Unreached = dyn_cast<UnreachableInst>(Terminator);
|
|
}
|
|
|
|
// If we got this far, the handler contains no invokes. We should have seen
|
|
// at least one return or unreachable instruction. We'll insert an invoke of
|
|
// llvm.donothing ahead of that instruction.
|
|
assert(Ret || Unreached);
|
|
TerminatorInst *Term;
|
|
if (Ret)
|
|
Term = Ret;
|
|
else
|
|
Term = Unreached;
|
|
BasicBlock *OldRetBB = Term->getParent();
|
|
BasicBlock *NewRetBB = SplitBlock(OldRetBB, Term, DT);
|
|
// SplitBlock adds an unconditional branch instruction at the end of the
|
|
// parent block. We want to replace that with an invoke call, so we can
|
|
// erase it now.
|
|
OldRetBB->getTerminator()->eraseFromParent();
|
|
BasicBlock *StubLandingPad = createStubLandingPad(Handler, PersonalityFn);
|
|
Function *F =
|
|
Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing);
|
|
InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB);
|
|
}
|
|
|
|
// FIXME: Consider sinking this into lib/Target/X86 somehow. TargetLowering
|
|
// usually doesn't build LLVM IR, so that's probably the wrong place.
|
|
Function *WinEHPrepare::createHandlerFunc(Type *RetTy, const Twine &Name,
|
|
Module *M, Value *&ParentFP) {
|
|
// x64 uses a two-argument prototype where the parent FP is the second
|
|
// argument. x86 uses no arguments, just the incoming EBP value.
|
|
LLVMContext &Context = M->getContext();
|
|
FunctionType *FnType;
|
|
if (TheTriple.getArch() == Triple::x86_64) {
|
|
Type *Int8PtrType = Type::getInt8PtrTy(Context);
|
|
Type *ArgTys[2] = {Int8PtrType, Int8PtrType};
|
|
FnType = FunctionType::get(RetTy, ArgTys, false);
|
|
} else {
|
|
FnType = FunctionType::get(RetTy, None, false);
|
|
}
|
|
|
|
Function *Handler =
|
|
Function::Create(FnType, GlobalVariable::InternalLinkage, Name, M);
|
|
BasicBlock *Entry = BasicBlock::Create(Context, "entry");
|
|
Handler->getBasicBlockList().push_front(Entry);
|
|
if (TheTriple.getArch() == Triple::x86_64) {
|
|
ParentFP = &(Handler->getArgumentList().back());
|
|
} else {
|
|
assert(M);
|
|
Function *FrameAddressFn =
|
|
Intrinsic::getDeclaration(M, Intrinsic::frameaddress);
|
|
Value *Args[1] = {ConstantInt::get(Type::getInt32Ty(Context), 1)};
|
|
ParentFP = CallInst::Create(FrameAddressFn, Args, "parent_fp",
|
|
&Handler->getEntryBlock());
|
|
}
|
|
return Handler;
|
|
}
|
|
|
|
bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
|
|
LandingPadInst *LPad, BasicBlock *StartBB,
|
|
FrameVarInfoMap &VarInfo) {
|
|
Module *M = SrcFn->getParent();
|
|
LLVMContext &Context = M->getContext();
|
|
Type *Int8PtrType = Type::getInt8PtrTy(Context);
|
|
|
|
// Create a new function to receive the handler contents.
|
|
Value *ParentFP;
|
|
Function *Handler;
|
|
if (Action->getType() == Catch) {
|
|
Handler = createHandlerFunc(Int8PtrType, SrcFn->getName() + ".catch", M,
|
|
ParentFP);
|
|
} else {
|
|
Handler = createHandlerFunc(Type::getVoidTy(Context),
|
|
SrcFn->getName() + ".cleanup", M, ParentFP);
|
|
}
|
|
HandlerToParentFP[Handler] = ParentFP;
|
|
Handler->addFnAttr("wineh-parent", SrcFn->getName());
|
|
BasicBlock *Entry = &Handler->getEntryBlock();
|
|
|
|
// Generate a standard prolog to setup the frame recovery structure.
|
|
IRBuilder<> Builder(Context);
|
|
Builder.SetInsertPoint(Entry);
|
|
Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
|
|
|
|
std::unique_ptr<WinEHCloningDirectorBase> Director;
|
|
|
|
ValueToValueMapTy VMap;
|
|
|
|
LandingPadMap &LPadMap = LPadMaps[LPad];
|
|
if (!LPadMap.isInitialized())
|
|
LPadMap.mapLandingPad(LPad);
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
Constant *Sel = CatchAction->getSelector();
|
|
Director.reset(new WinEHCatchDirector(Handler, ParentFP, Sel, VarInfo,
|
|
LPadMap, NestedLPtoOriginalLP, DT,
|
|
EHBlocks));
|
|
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
|
|
ConstantInt::get(Type::getInt32Ty(Context), 1));
|
|
} else {
|
|
Director.reset(
|
|
new WinEHCleanupDirector(Handler, ParentFP, VarInfo, LPadMap));
|
|
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
|
|
UndefValue::get(Type::getInt32Ty(Context)));
|
|
}
|
|
|
|
SmallVector<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;
|
|
}
|
|
|
|
// The landing pad value may be used by PHI nodes. It will ultimately be
|
|
// eliminated, but we need it in the map for intermediate handling.
|
|
VMap[LPad] = UndefValue::get(LPad->getType());
|
|
|
|
// Skip over PHIs and, if applicable, landingpad instructions.
|
|
II = StartBB->getFirstInsertionPt();
|
|
|
|
CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap,
|
|
/*ModuleLevelChanges=*/false, Returns, "",
|
|
&OutlinedFunctionInfo, Director.get());
|
|
|
|
// Move all the instructions in the cloned "entry" block into our entry block.
|
|
// Depending on how the parent function was laid out, the block that will
|
|
// correspond to the outlined entry block may not be the first block in the
|
|
// list. We can recognize it, however, as the cloned block which has no
|
|
// predecessors. Any other block wouldn't have been cloned if it didn't
|
|
// have a predecessor which was also cloned.
|
|
Function::iterator ClonedIt = std::next(Function::iterator(Entry));
|
|
while (!pred_empty(ClonedIt))
|
|
++ClonedIt;
|
|
BasicBlock *ClonedEntryBB = ClonedIt;
|
|
assert(ClonedEntryBB);
|
|
Entry->getInstList().splice(Entry->end(), ClonedEntryBB->getInstList());
|
|
ClonedEntryBB->eraseFromParent();
|
|
|
|
// Make sure we can identify the handler's personality later.
|
|
addStubInvokeToHandlerIfNeeded(Handler, 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 = SplitBlock(StartBB, StartBB->getFirstInsertionPt(), DT);
|
|
}
|
|
IRBuilder<> Builder(HandlerBB->getFirstInsertionPt());
|
|
Function *EHCodeFn = Intrinsic::getDeclaration(
|
|
StartBB->getParent()->getParent(), Intrinsic::eh_exceptioncode);
|
|
Value *Code = Builder.CreateCall(EHCodeFn, {}, "sehcode");
|
|
Code = Builder.CreateIntToPtr(Code, SEHExceptionCodeSlot->getAllocatedType());
|
|
Builder.CreateStore(Code, SEHExceptionCodeSlot);
|
|
CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB));
|
|
TinyPtrVector<BasicBlock *> Targets(HandlerBB);
|
|
CatchAction->setReturnTargets(Targets);
|
|
}
|
|
|
|
void LandingPadMap::mapLandingPad(const LandingPadInst *LPad) {
|
|
// Each instance of this class should only ever be used to map a single
|
|
// landing pad.
|
|
assert(OriginLPad == nullptr || OriginLPad == LPad);
|
|
|
|
// If the landing pad has already been mapped, there's nothing more to do.
|
|
if (OriginLPad == LPad)
|
|
return;
|
|
|
|
OriginLPad = LPad;
|
|
|
|
// The landingpad instruction returns an aggregate value. Typically, its
|
|
// value will be passed to a pair of extract value instructions and the
|
|
// results of those extracts will have been promoted to reg values before
|
|
// this routine is called.
|
|
for (auto *U : LPad->users()) {
|
|
const ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
|
|
if (!Extract)
|
|
continue;
|
|
assert(Extract->getNumIndices() == 1 &&
|
|
"Unexpected operation: extracting both landing pad values");
|
|
unsigned int Idx = *(Extract->idx_begin());
|
|
assert((Idx == 0 || Idx == 1) &&
|
|
"Unexpected operation: extracting an unknown landing pad element");
|
|
if (Idx == 0) {
|
|
ExtractedEHPtrs.push_back(Extract);
|
|
} else if (Idx == 1) {
|
|
ExtractedSelectors.push_back(Extract);
|
|
}
|
|
}
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static bool isFrameAddressCall(const Value *V) {
|
|
return match(const_cast<Value *>(V),
|
|
m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// If this is one of the boilerplate landing pad instructions, skip it.
|
|
// The instruction will have already been remapped in VMap.
|
|
if (LPadMap.isLandingPadSpecificInst(Inst))
|
|
return CloningDirector::SkipInstruction;
|
|
|
|
// Nested landing pads that have not already been outlined will be cloned as
|
|
// stubs, with just the landingpad instruction and an unreachable instruction.
|
|
// When all landingpads have been outlined, we'll replace this with the
|
|
// llvm.eh.actions call and indirect branch created when the landing pad was
|
|
// outlined.
|
|
if (auto *LPad = dyn_cast<LandingPadInst>(Inst)) {
|
|
return handleLandingPad(VMap, LPad, NewBB);
|
|
}
|
|
|
|
// Nested landing pads that have already been outlined will be cloned in their
|
|
// outlined form, but we need to intercept the ibr instruction to filter out
|
|
// targets that do not return to the handler we are outlining.
|
|
if (auto *IBr = dyn_cast<IndirectBrInst>(Inst)) {
|
|
return handleIndirectBr(VMap, IBr, NewBB);
|
|
}
|
|
|
|
if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
|
|
return handleInvoke(VMap, Invoke, NewBB);
|
|
|
|
if (auto *Resume = dyn_cast<ResumeInst>(Inst))
|
|
return handleResume(VMap, Resume, NewBB);
|
|
|
|
if (auto *Cmp = dyn_cast<CmpInst>(Inst))
|
|
return handleCompare(VMap, Cmp, NewBB);
|
|
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
|
|
return handleBeginCatch(VMap, Inst, NewBB);
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
|
|
return handleEndCatch(VMap, Inst, NewBB);
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
|
|
return handleTypeIdFor(VMap, Inst, NewBB);
|
|
|
|
// When outlining llvm.frameaddress(i32 0), remap that to the second argument,
|
|
// which is the FP of the parent.
|
|
if (isFrameAddressCall(Inst)) {
|
|
VMap[Inst] = ParentFP;
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
// Continue with the default cloning behavior.
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad(
|
|
ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
|
|
// If the instruction after the landing pad is a call to llvm.eh.actions
|
|
// the landing pad has already been outlined. In this case, we should
|
|
// clone it because it may return to a block in the handler we are
|
|
// outlining now that would otherwise be unreachable. The landing pads
|
|
// are sorted before outlining begins to enable this case to work
|
|
// properly.
|
|
const Instruction *NextI = LPad->getNextNode();
|
|
if (match(NextI, m_Intrinsic<Intrinsic::eh_actions>()))
|
|
return CloningDirector::CloneInstruction;
|
|
|
|
// If the landing pad hasn't been outlined yet, the landing pad we are
|
|
// outlining now does not dominate it and so it cannot return to a block
|
|
// in this handler. In that case, we can just insert a stub landing
|
|
// pad now and patch it up later.
|
|
Instruction *NewInst = LPad->clone();
|
|
if (LPad->hasName())
|
|
NewInst->setName(LPad->getName());
|
|
// Save this correlation for later processing.
|
|
NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad;
|
|
VMap[LPad] = NewInst;
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(NewInst);
|
|
InstList.push_back(new UnreachableInst(NewBB->getContext()));
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// The argument to the call is some form of the first element of the
|
|
// landingpad aggregate value, but that doesn't matter. It isn't used
|
|
// here.
|
|
// The second argument is an outparameter where the exception object will be
|
|
// stored. Typically the exception object is a scalar, but it can be an
|
|
// aggregate when catching by value.
|
|
// FIXME: Leave something behind to indicate where the exception object lives
|
|
// for this handler. Should it be part of llvm.eh.actions?
|
|
assert(ExceptionObjectVar == nullptr && "Multiple calls to "
|
|
"llvm.eh.begincatch found while "
|
|
"outlining catch handler.");
|
|
ExceptionObjectVar = Inst->getOperand(1)->stripPointerCasts();
|
|
if (isa<ConstantPointerNull>(ExceptionObjectVar))
|
|
return CloningDirector::SkipInstruction;
|
|
assert(cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() &&
|
|
"catch parameter is not static alloca");
|
|
Materializer.escapeCatchObject(ExceptionObjectVar);
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap,
|
|
const Instruction *Inst, BasicBlock *NewBB) {
|
|
auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
|
|
// It might be interesting to track whether or not we are inside a catch
|
|
// function, but that might make the algorithm more brittle than it needs
|
|
// to be.
|
|
|
|
// The end catch call can occur in one of two places: either in a
|
|
// landingpad block that is part of the catch handlers exception mechanism,
|
|
// or at the end of the catch block. However, a catch-all handler may call
|
|
// end catch from the original landing pad. If the call occurs in a nested
|
|
// landing pad block, we must skip it and continue so that the landing pad
|
|
// gets cloned.
|
|
auto *ParentBB = IntrinCall->getParent();
|
|
if (ParentBB->isLandingPad() && !LPadMap.isOriginLandingPadBlock(ParentBB))
|
|
return CloningDirector::SkipInstruction;
|
|
|
|
// If an end catch occurs anywhere else we want to terminate the handler
|
|
// with a return to the code that follows the endcatch call. If the
|
|
// next instruction is not an unconditional branch, we need to split the
|
|
// block to provide a clear target for the return instruction.
|
|
BasicBlock *ContinueBB;
|
|
auto Next = std::next(BasicBlock::const_iterator(IntrinCall));
|
|
const BranchInst *Branch = dyn_cast<BranchInst>(Next);
|
|
if (!Branch || !Branch->isUnconditional()) {
|
|
// We're interrupting the cloning process at this location, so the
|
|
// const_cast we're doing here will not cause a problem.
|
|
ContinueBB = SplitBlock(const_cast<BasicBlock *>(ParentBB),
|
|
const_cast<Instruction *>(cast<Instruction>(Next)));
|
|
} else {
|
|
ContinueBB = Branch->getSuccessor(0);
|
|
}
|
|
|
|
ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueBB), NewBB);
|
|
ReturnTargets.push_back(ContinueBB);
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block so that
|
|
// the branch instruction will be skipped.
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
|
|
Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
|
|
// This causes a replacement that will collapse the landing pad CFG based
|
|
// on the filter function we intend to match.
|
|
if (Selector == CurrentSelector)
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
|
|
else
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
|
|
// Tell the caller not to clone this instruction.
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleIndirectBr(
|
|
ValueToValueMapTy &VMap,
|
|
const IndirectBrInst *IBr,
|
|
BasicBlock *NewBB) {
|
|
// If this indirect branch is not part of a landing pad block, just clone it.
|
|
const BasicBlock *ParentBB = IBr->getParent();
|
|
if (!ParentBB->isLandingPad())
|
|
return CloningDirector::CloneInstruction;
|
|
|
|
// If it is part of a landing pad, we want to filter out target blocks
|
|
// that are not part of the handler we are outlining.
|
|
const LandingPadInst *LPad = ParentBB->getLandingPadInst();
|
|
|
|
// Save this correlation for later processing.
|
|
NestedLPtoOriginalLP[cast<LandingPadInst>(VMap[LPad])] = LPad;
|
|
|
|
// We should only get here for landing pads that have already been outlined.
|
|
assert(match(LPad->getNextNode(), m_Intrinsic<Intrinsic::eh_actions>()));
|
|
|
|
// Copy the indirectbr, but only include targets that were previously
|
|
// identified as EH blocks and are dominated by the nested landing pad.
|
|
SetVector<const BasicBlock *> ReturnTargets;
|
|
for (int I = 0, E = IBr->getNumDestinations(); I < E; ++I) {
|
|
auto *TargetBB = IBr->getDestination(I);
|
|
if (EHBlocks.count(const_cast<BasicBlock*>(TargetBB)) &&
|
|
DT->dominates(ParentBB, TargetBB)) {
|
|
DEBUG(dbgs() << " Adding destination " << TargetBB->getName() << "\n");
|
|
ReturnTargets.insert(TargetBB);
|
|
}
|
|
}
|
|
IndirectBrInst *NewBranch =
|
|
IndirectBrInst::Create(const_cast<Value *>(IBr->getAddress()),
|
|
ReturnTargets.size(), NewBB);
|
|
for (auto *Target : ReturnTargets)
|
|
NewBranch->addDestination(const_cast<BasicBlock*>(Target));
|
|
|
|
// The operands and targets of the branch instruction are remapped later
|
|
// because it is a terminator. Tell the cloning code to clone the
|
|
// blocks we just added to the target list.
|
|
return CloningDirector::CloneSuccessors;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap,
|
|
const InvokeInst *Invoke, BasicBlock *NewBB) {
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
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
|
|
WinEHCatchDirector::handleCompare(ValueToValueMapTy &VMap,
|
|
const CmpInst *Compare, BasicBlock *NewBB) {
|
|
const IntrinsicInst *IntrinCall = nullptr;
|
|
if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
|
|
IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(0));
|
|
} else if (match(Compare->getOperand(1),
|
|
m_Intrinsic<Intrinsic::eh_typeid_for>())) {
|
|
IntrinCall = dyn_cast<IntrinsicInst>(Compare->getOperand(1));
|
|
}
|
|
if (IntrinCall) {
|
|
Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
|
|
// This causes a replacement that will collapse the landing pad CFG based
|
|
// on the filter function we intend to match.
|
|
if (Selector == CurrentSelector->stripPointerCasts()) {
|
|
VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
|
|
} else {
|
|
VMap[Compare] = ConstantInt::get(SelectorIDType, 0);
|
|
}
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad(
|
|
ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
|
|
// The MS runtime will terminate the process if an exception occurs in a
|
|
// cleanup handler, so we shouldn't encounter landing pads in the actual
|
|
// cleanup code, but they may appear in catch blocks. Depending on where
|
|
// we started cloning we may see one, but it will get dropped during dead
|
|
// block pruning.
|
|
Instruction *NewInst = new UnreachableInst(NewBB->getContext());
|
|
VMap[LPad] = NewInst;
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(NewInst);
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// Cleanup code may flow into catch blocks or the catch block may be part
|
|
// of a branch that will be optimized away. We'll insert a return
|
|
// instruction now, but it may be pruned before the cloning process is
|
|
// complete.
|
|
ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// Cleanup handlers nested within catch handlers may begin with a call to
|
|
// eh.endcatch. We can just ignore that instruction.
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// If we encounter a selector comparison while cloning a cleanup handler,
|
|
// we want to stop cloning immediately. Anything after the dispatch
|
|
// will be outlined into a different handler.
|
|
BasicBlock *CatchHandler;
|
|
Constant *Selector;
|
|
BasicBlock *NextBB;
|
|
if (isSelectorDispatch(const_cast<BasicBlock *>(Inst->getParent()),
|
|
CatchHandler, Selector, NextBB)) {
|
|
ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
// If eg.typeid.for is called for any other reason, it can be ignored.
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleIndirectBr(
|
|
ValueToValueMapTy &VMap,
|
|
const IndirectBrInst *IBr,
|
|
BasicBlock *NewBB) {
|
|
// No special handling is required for cleanup cloning.
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleInvoke(
|
|
ValueToValueMapTy &VMap, const InvokeInst *Invoke, BasicBlock *NewBB) {
|
|
// All invokes in cleanup handlers can be replaced with calls.
|
|
SmallVector<Value *, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
|
|
// Insert a normal call instruction...
|
|
CallInst *NewCall =
|
|
CallInst::Create(const_cast<Value *>(Invoke->getCalledValue()), CallArgs,
|
|
Invoke->getName(), NewBB);
|
|
NewCall->setCallingConv(Invoke->getCallingConv());
|
|
NewCall->setAttributes(Invoke->getAttributes());
|
|
NewCall->setDebugLoc(Invoke->getDebugLoc());
|
|
VMap[Invoke] = NewCall;
|
|
|
|
// Remap the operands.
|
|
llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer);
|
|
|
|
// Insert an unconditional branch to the normal destination.
|
|
BranchInst::Create(Invoke->getNormalDest(), NewBB);
|
|
|
|
// The unwind destination won't be cloned into the new function, so
|
|
// we don't need to clean up its phi nodes.
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block.
|
|
return CloningDirector::CloneSuccessors;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
|
|
ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) {
|
|
ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block so that
|
|
// the branch instruction will be skipped.
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCleanupDirector::handleCompare(ValueToValueMapTy &VMap,
|
|
const CmpInst *Compare, BasicBlock *NewBB) {
|
|
if (match(Compare->getOperand(0), m_Intrinsic<Intrinsic::eh_typeid_for>()) ||
|
|
match(Compare->getOperand(1), m_Intrinsic<Intrinsic::eh_typeid_for>())) {
|
|
VMap[Compare] = ConstantInt::get(SelectorIDType, 1);
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
|
|
Function *OutlinedFn, Value *ParentFP, FrameVarInfoMap &FrameVarInfo)
|
|
: FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
|
|
BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
|
|
|
|
// New allocas should be inserted in the entry block, but after the parent FP
|
|
// is established if it is an instruction.
|
|
Instruction *InsertPoint = EntryBB->getFirstInsertionPt();
|
|
if (auto *FPInst = dyn_cast<Instruction>(ParentFP))
|
|
InsertPoint = FPInst->getNextNode();
|
|
Builder.SetInsertPoint(EntryBB, InsertPoint);
|
|
}
|
|
|
|
Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
|
|
// If we're asked to materialize a static alloca, we temporarily create an
|
|
// alloca in the outlined function and add this to the FrameVarInfo map. When
|
|
// all the outlining is complete, we'll replace these temporary allocas with
|
|
// calls to llvm.framerecover.
|
|
if (auto *AV = dyn_cast<AllocaInst>(V)) {
|
|
assert(AV->isStaticAlloca() &&
|
|
"cannot materialize un-demoted dynamic alloca");
|
|
AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone());
|
|
Builder.Insert(NewAlloca, AV->getName());
|
|
FrameVarInfo[AV].push_back(NewAlloca);
|
|
return NewAlloca;
|
|
}
|
|
|
|
if (isa<Instruction>(V) || isa<Argument>(V)) {
|
|
Function *Parent = isa<Instruction>(V)
|
|
? cast<Instruction>(V)->getParent()->getParent()
|
|
: cast<Argument>(V)->getParent();
|
|
errs()
|
|
<< "Failed to demote instruction used in exception handler of function "
|
|
<< GlobalValue::getRealLinkageName(Parent->getName()) << ":\n";
|
|
errs() << " " << *V << '\n';
|
|
report_fatal_error("WinEHPrepare failed to demote instruction");
|
|
}
|
|
|
|
// Don't materialize other values.
|
|
return nullptr;
|
|
}
|
|
|
|
void 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;
|
|
|
|
// Skip over filter clauses.
|
|
if (LPad->isFilter(HandlersFound)) {
|
|
++HandlersFound;
|
|
continue;
|
|
}
|
|
|
|
// See if the clause we're looking for is a catch-all.
|
|
// If so, the catch begins immediately.
|
|
Constant *ExpectedSelector =
|
|
LPad->getClause(HandlersFound)->stripPointerCasts();
|
|
if (isa<ConstantPointerNull>(ExpectedSelector)) {
|
|
// The catch all must occur last.
|
|
assert(HandlersFound == NumClauses - 1);
|
|
|
|
// There can be additional selector dispatches in the call chain that we
|
|
// need to ignore.
|
|
BasicBlock *CatchBlock = nullptr;
|
|
Constant *Selector;
|
|
while (BB && isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
|
|
DEBUG(dbgs() << " Found extra catch dispatch in block "
|
|
<< CatchBlock->getName() << "\n");
|
|
BB = NextBB;
|
|
}
|
|
|
|
// Add the catch handler to the action list.
|
|
CatchHandler *Action = nullptr;
|
|
if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
|
|
// If the CatchHandlerMap already has an entry for this BB, re-use it.
|
|
Action = CatchHandlerMap[BB];
|
|
assert(Action->getSelector() == ExpectedSelector);
|
|
} else {
|
|
// We don't expect a selector dispatch, but there may be a call to
|
|
// llvm.eh.begincatch, which separates catch handling code from
|
|
// cleanup code in the same control flow. This call looks for the
|
|
// begincatch intrinsic.
|
|
Action = findCatchHandler(BB, NextBB, VisitedBlocks);
|
|
if (Action) {
|
|
// For C++ EH, check if there is any interesting cleanup code before
|
|
// we begin the catch. This is important because cleanups cannot
|
|
// rethrow exceptions but code called from catches can. For SEH, it
|
|
// isn't important if some finally code before a catch-all is executed
|
|
// out of line or after recovering from the exception.
|
|
if (Personality == EHPersonality::MSVC_CXX)
|
|
findCleanupHandlers(Actions, BB, BB);
|
|
} else {
|
|
// If an action was not found, it means that the control flows
|
|
// directly into the catch-all handler and there is no cleanup code.
|
|
// That's an expected situation and we must create a catch action.
|
|
// Since this is a catch-all handler, the selector won't actually
|
|
// appear in the code anywhere. ExpectedSelector here is the constant
|
|
// null ptr that we got from the landing pad instruction.
|
|
Action = new CatchHandler(BB, ExpectedSelector, nullptr);
|
|
CatchHandlerMap[BB] = Action;
|
|
}
|
|
}
|
|
Actions.insertCatchHandler(Action);
|
|
DEBUG(dbgs() << " Catch all handler at block " << BB->getName() << "\n");
|
|
++HandlersFound;
|
|
|
|
// Once we reach a catch-all, don't expect to hit a resume instruction.
|
|
BB = nullptr;
|
|
break;
|
|
}
|
|
|
|
CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
|
|
assert(CatchAction);
|
|
|
|
// See if there is any interesting code executed before the dispatch.
|
|
findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
|
|
|
|
// When the source program contains multiple nested try blocks the catch
|
|
// handlers can get strung together in such a way that we can encounter
|
|
// a dispatch for a selector that we've already had a handler for.
|
|
if (CatchAction->getSelector()->stripPointerCasts() == ExpectedSelector) {
|
|
++HandlersFound;
|
|
|
|
// Add the catch handler to the action list.
|
|
DEBUG(dbgs() << " Found catch dispatch in block "
|
|
<< CatchAction->getStartBlock()->getName() << "\n");
|
|
Actions.insertCatchHandler(CatchAction);
|
|
} else {
|
|
// Under some circumstances optimized IR will flow unconditionally into a
|
|
// handler block without checking the selector. This can only happen if
|
|
// the landing pad has a catch-all handler and the handler for the
|
|
// preceeding catch clause is identical to the catch-call handler
|
|
// (typically an empty catch). In this case, the handler must be shared
|
|
// by all remaining clauses.
|
|
if (isa<ConstantPointerNull>(
|
|
CatchAction->getSelector()->stripPointerCasts())) {
|
|
DEBUG(dbgs() << " Applying early catch-all handler in block "
|
|
<< CatchAction->getStartBlock()->getName()
|
|
<< " to all remaining clauses.\n");
|
|
Actions.insertCatchHandler(CatchAction);
|
|
return;
|
|
}
|
|
|
|
DEBUG(dbgs() << " Found extra catch dispatch in block "
|
|
<< CatchAction->getStartBlock()->getName() << "\n");
|
|
}
|
|
|
|
// Move on to the block after the catch handler.
|
|
BB = NextBB;
|
|
}
|
|
|
|
// If we didn't wind up in a catch-all, see if there is any interesting code
|
|
// executed before the resume.
|
|
findCleanupHandlers(Actions, BB, BB);
|
|
|
|
// It's possible that some optimization moved code into a landingpad that
|
|
// wasn't
|
|
// previously being used for cleanup. If that happens, we need to execute
|
|
// that
|
|
// extra code from a cleanup handler.
|
|
if (Actions.includesCleanup() && !LPad->isCleanup())
|
|
LPad->setCleanup(true);
|
|
}
|
|
|
|
// This function searches starting with the input block for the next
|
|
// block that terminates with a branch whose condition is based on a selector
|
|
// comparison. This may be the input block. See the mapLandingPadBlocks
|
|
// comments for a discussion of control flow assumptions.
|
|
//
|
|
CatchHandler *WinEHPrepare::findCatchHandler(BasicBlock *BB,
|
|
BasicBlock *&NextBB,
|
|
VisitedBlockSet &VisitedBlocks) {
|
|
// See if we've already found a catch handler use it.
|
|
// Call count() first to avoid creating a null entry for blocks
|
|
// we haven't seen before.
|
|
if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
|
|
CatchHandler *Action = cast<CatchHandler>(CatchHandlerMap[BB]);
|
|
NextBB = Action->getNextBB();
|
|
return Action;
|
|
}
|
|
|
|
// VisitedBlocks applies only to the current search. We still
|
|
// need to consider blocks that we've visited while mapping other
|
|
// landing pads.
|
|
VisitedBlocks.insert(BB);
|
|
|
|
BasicBlock *CatchBlock = nullptr;
|
|
Constant *Selector = nullptr;
|
|
|
|
// If this is the first time we've visited this block from any landing pad
|
|
// look to see if it is a selector dispatch block.
|
|
if (!CatchHandlerMap.count(BB)) {
|
|
if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
|
|
CatchHandler *Action = new CatchHandler(BB, Selector, NextBB);
|
|
CatchHandlerMap[BB] = Action;
|
|
return Action;
|
|
}
|
|
// If we encounter a block containing an llvm.eh.begincatch before we
|
|
// find a selector dispatch block, the handler is assumed to be
|
|
// reached unconditionally. This happens for catch-all blocks, but
|
|
// it can also happen for other catch handlers that have been combined
|
|
// with the catch-all handler during optimization.
|
|
if (isCatchBlock(BB)) {
|
|
PointerType *Int8PtrTy = Type::getInt8PtrTy(BB->getContext());
|
|
Constant *NullSelector = ConstantPointerNull::get(Int8PtrTy);
|
|
CatchHandler *Action = new CatchHandler(BB, NullSelector, nullptr);
|
|
CatchHandlerMap[BB] = Action;
|
|
return Action;
|
|
}
|
|
}
|
|
|
|
// 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 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 =
|
|
SplitBlock(BB, FinallyCall.getInstruction()->getNextNode(), DT);
|
|
} else {
|
|
if (FinallyCall.isInvoke()) {
|
|
SuccBB =
|
|
cast<InvokeInst>(FinallyCall.getInstruction())->getNormalDest();
|
|
} else {
|
|
SuccBB = BB->getUniqueSuccessor();
|
|
assert(SuccBB &&
|
|
"splitOutlinedFinallyCalls didn't insert a branch");
|
|
}
|
|
}
|
|
BB = SuccBB;
|
|
if (BB == EndBB)
|
|
return;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// 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<std::unique_ptr<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 = make_unique<CatchHandler>(/*BB=*/nullptr, Selector,
|
|
/*NextBB=*/nullptr);
|
|
CH->setHandlerBlockOrFunc(Handler);
|
|
CH->setExceptionVarIndex(EHObjIndexVal);
|
|
Actions.push_back(std::move(CH));
|
|
} else if (ActionKind == 0) {
|
|
Constant *Handler = cast<Constant>(II->getArgOperand(I + 1));
|
|
I += 2;
|
|
auto CH = make_unique<CleanupHandler>(/*BB=*/nullptr);
|
|
CH->setHandlerBlockOrFunc(Handler);
|
|
Actions.push_back(std::move(CH));
|
|
} else {
|
|
llvm_unreachable("Expected either a catch or cleanup handler!");
|
|
}
|
|
}
|
|
std::reverse(Actions.begin(), Actions.end());
|
|
}
|
|
|
|
namespace {
|
|
struct WinEHNumbering {
|
|
WinEHNumbering(WinEHFuncInfo &FuncInfo) : FuncInfo(FuncInfo),
|
|
CurrentBaseState(-1), NextState(0) {}
|
|
|
|
WinEHFuncInfo &FuncInfo;
|
|
int CurrentBaseState;
|
|
int NextState;
|
|
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> HandlerStack;
|
|
SmallPtrSet<const Function *, 4> VisitedHandlers;
|
|
|
|
int currentEHNumber() const {
|
|
return HandlerStack.empty() ? CurrentBaseState : HandlerStack.back()->getEHState();
|
|
}
|
|
|
|
void createUnwindMapEntry(int ToState, ActionHandler *AH);
|
|
void createTryBlockMapEntry(int TryLow, int TryHigh,
|
|
ArrayRef<CatchHandler *> Handlers);
|
|
void processCallSite(MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
|
|
ImmutableCallSite CS);
|
|
void popUnmatchedActions(int FirstMismatch);
|
|
void calculateStateNumbers(const Function &F);
|
|
void findActionRootLPads(const Function &F);
|
|
};
|
|
}
|
|
|
|
void WinEHNumbering::createUnwindMapEntry(int ToState, ActionHandler *AH) {
|
|
WinEHUnwindMapEntry UME;
|
|
UME.ToState = ToState;
|
|
if (auto *CH = dyn_cast_or_null<CleanupHandler>(AH))
|
|
UME.Cleanup = cast<Function>(CH->getHandlerBlockOrFunc());
|
|
else
|
|
UME.Cleanup = nullptr;
|
|
FuncInfo.UnwindMap.push_back(UME);
|
|
}
|
|
|
|
void WinEHNumbering::createTryBlockMapEntry(int TryLow, int TryHigh,
|
|
ArrayRef<CatchHandler *> Handlers) {
|
|
// See if we already have an entry for this set of handlers.
|
|
// This is using iterators rather than a range-based for loop because
|
|
// if we find the entry we're looking for we'll need the iterator to erase it.
|
|
int NumHandlers = Handlers.size();
|
|
auto I = FuncInfo.TryBlockMap.begin();
|
|
auto E = FuncInfo.TryBlockMap.end();
|
|
for ( ; I != E; ++I) {
|
|
auto &Entry = *I;
|
|
if (Entry.HandlerArray.size() != (size_t)NumHandlers)
|
|
continue;
|
|
int N;
|
|
for (N = 0; N < NumHandlers; ++N) {
|
|
if (Entry.HandlerArray[N].Handler != Handlers[N]->getHandlerBlockOrFunc())
|
|
break; // breaks out of inner loop
|
|
}
|
|
// If all the handlers match, this is what we were looking for.
|
|
if (N == NumHandlers) {
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If we found an existing entry for this set of handlers, extend the range
|
|
// but move the entry to the end of the map vector. The order of entries
|
|
// in the map is critical to the way that the runtime finds handlers.
|
|
// FIXME: Depending on what has happened with block ordering, this may
|
|
// incorrectly combine entries that should remain separate.
|
|
if (I != E) {
|
|
// Copy the existing entry.
|
|
WinEHTryBlockMapEntry Entry = *I;
|
|
Entry.TryLow = std::min(TryLow, Entry.TryLow);
|
|
Entry.TryHigh = std::max(TryHigh, Entry.TryHigh);
|
|
assert(Entry.TryLow <= Entry.TryHigh);
|
|
// Erase the old entry and add this one to the back.
|
|
FuncInfo.TryBlockMap.erase(I);
|
|
FuncInfo.TryBlockMap.push_back(Entry);
|
|
return;
|
|
}
|
|
|
|
// If we didn't find an entry, create a new one.
|
|
WinEHTryBlockMapEntry TBME;
|
|
TBME.TryLow = TryLow;
|
|
TBME.TryHigh = TryHigh;
|
|
assert(TBME.TryLow <= TBME.TryHigh);
|
|
for (CatchHandler *CH : Handlers) {
|
|
WinEHHandlerType HT;
|
|
if (CH->getSelector()->isNullValue()) {
|
|
HT.Adjectives = 0x40;
|
|
HT.TypeDescriptor = nullptr;
|
|
} else {
|
|
auto *GV = cast<GlobalVariable>(CH->getSelector()->stripPointerCasts());
|
|
// Selectors are always pointers to GlobalVariables with 'struct' type.
|
|
// The struct has two fields, adjectives and a type descriptor.
|
|
auto *CS = cast<ConstantStruct>(GV->getInitializer());
|
|
HT.Adjectives =
|
|
cast<ConstantInt>(CS->getAggregateElement(0U))->getZExtValue();
|
|
HT.TypeDescriptor =
|
|
cast<GlobalVariable>(CS->getAggregateElement(1)->stripPointerCasts());
|
|
}
|
|
HT.Handler = cast<Function>(CH->getHandlerBlockOrFunc());
|
|
HT.CatchObjRecoverIdx = CH->getExceptionVarIndex();
|
|
TBME.HandlerArray.push_back(HT);
|
|
}
|
|
FuncInfo.TryBlockMap.push_back(TBME);
|
|
}
|
|
|
|
static void print_name(const Value *V) {
|
|
#ifndef NDEBUG
|
|
if (!V) {
|
|
DEBUG(dbgs() << "null");
|
|
return;
|
|
}
|
|
|
|
if (const auto *F = dyn_cast<Function>(V))
|
|
DEBUG(dbgs() << F->getName());
|
|
else
|
|
DEBUG(V->dump());
|
|
#endif
|
|
}
|
|
|
|
void WinEHNumbering::processCallSite(
|
|
MutableArrayRef<std::unique_ptr<ActionHandler>> Actions,
|
|
ImmutableCallSite CS) {
|
|
DEBUG(dbgs() << "processCallSite (EH state = " << currentEHNumber()
|
|
<< ") for: ");
|
|
print_name(CS ? CS.getCalledValue() : nullptr);
|
|
DEBUG(dbgs() << '\n');
|
|
|
|
DEBUG(dbgs() << "HandlerStack: \n");
|
|
for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
|
|
DEBUG(dbgs() << " ");
|
|
print_name(HandlerStack[I]->getHandlerBlockOrFunc());
|
|
DEBUG(dbgs() << '\n');
|
|
}
|
|
DEBUG(dbgs() << "Actions: \n");
|
|
for (int I = 0, E = Actions.size(); I < E; ++I) {
|
|
DEBUG(dbgs() << " ");
|
|
print_name(Actions[I]->getHandlerBlockOrFunc());
|
|
DEBUG(dbgs() << '\n');
|
|
}
|
|
int FirstMismatch = 0;
|
|
for (int E = std::min(HandlerStack.size(), Actions.size()); FirstMismatch < E;
|
|
++FirstMismatch) {
|
|
if (HandlerStack[FirstMismatch]->getHandlerBlockOrFunc() !=
|
|
Actions[FirstMismatch]->getHandlerBlockOrFunc())
|
|
break;
|
|
}
|
|
|
|
// Remove unmatched actions from the stack and process their EH states.
|
|
popUnmatchedActions(FirstMismatch);
|
|
|
|
DEBUG(dbgs() << "Pushing actions for CallSite: ");
|
|
print_name(CS ? CS.getCalledValue() : nullptr);
|
|
DEBUG(dbgs() << '\n');
|
|
|
|
bool LastActionWasCatch = false;
|
|
const LandingPadInst *LastRootLPad = nullptr;
|
|
for (size_t I = FirstMismatch; I != Actions.size(); ++I) {
|
|
// We can reuse eh states when pushing two catches for the same invoke.
|
|
bool CurrActionIsCatch = isa<CatchHandler>(Actions[I].get());
|
|
auto *Handler = cast<Function>(Actions[I]->getHandlerBlockOrFunc());
|
|
// Various conditions can lead to a handler being popped from the
|
|
// stack and re-pushed later. That shouldn't create a new state.
|
|
// FIXME: Can code optimization lead to re-used handlers?
|
|
if (FuncInfo.HandlerEnclosedState.count(Handler)) {
|
|
// If we already assigned the state enclosed by this handler re-use it.
|
|
Actions[I]->setEHState(FuncInfo.HandlerEnclosedState[Handler]);
|
|
continue;
|
|
}
|
|
const LandingPadInst* RootLPad = FuncInfo.RootLPad[Handler];
|
|
if (CurrActionIsCatch && LastActionWasCatch && RootLPad == LastRootLPad) {
|
|
DEBUG(dbgs() << "setEHState for handler to " << currentEHNumber() << "\n");
|
|
Actions[I]->setEHState(currentEHNumber());
|
|
} else {
|
|
DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber() << ", ");
|
|
print_name(Actions[I]->getHandlerBlockOrFunc());
|
|
DEBUG(dbgs() << ") with EH state " << NextState << "\n");
|
|
createUnwindMapEntry(currentEHNumber(), Actions[I].get());
|
|
DEBUG(dbgs() << "setEHState for handler to " << NextState << "\n");
|
|
Actions[I]->setEHState(NextState);
|
|
NextState++;
|
|
}
|
|
HandlerStack.push_back(std::move(Actions[I]));
|
|
LastActionWasCatch = CurrActionIsCatch;
|
|
LastRootLPad = RootLPad;
|
|
}
|
|
|
|
// This is used to defer numbering states for a handler until after the
|
|
// last time it appears in an invoke action list.
|
|
if (CS.isInvoke()) {
|
|
for (int I = 0, E = HandlerStack.size(); I < E; ++I) {
|
|
auto *Handler = cast<Function>(HandlerStack[I]->getHandlerBlockOrFunc());
|
|
if (FuncInfo.LastInvoke[Handler] != cast<InvokeInst>(CS.getInstruction()))
|
|
continue;
|
|
FuncInfo.LastInvokeVisited[Handler] = true;
|
|
DEBUG(dbgs() << "Last invoke of ");
|
|
print_name(Handler);
|
|
DEBUG(dbgs() << " has been visited.\n");
|
|
}
|
|
}
|
|
|
|
DEBUG(dbgs() << "In EHState " << currentEHNumber() << " for CallSite: ");
|
|
print_name(CS ? CS.getCalledValue() : nullptr);
|
|
DEBUG(dbgs() << '\n');
|
|
}
|
|
|
|
void WinEHNumbering::popUnmatchedActions(int FirstMismatch) {
|
|
// Don't recurse while we are looping over the handler stack. Instead, defer
|
|
// the numbering of the catch handlers until we are done popping.
|
|
SmallVector<CatchHandler *, 4> PoppedCatches;
|
|
for (int I = HandlerStack.size() - 1; I >= FirstMismatch; --I) {
|
|
std::unique_ptr<ActionHandler> Handler = HandlerStack.pop_back_val();
|
|
if (isa<CatchHandler>(Handler.get()))
|
|
PoppedCatches.push_back(cast<CatchHandler>(Handler.release()));
|
|
}
|
|
|
|
int TryHigh = NextState - 1;
|
|
int LastTryLowIdx = 0;
|
|
for (int I = 0, E = PoppedCatches.size(); I != E; ++I) {
|
|
CatchHandler *CH = PoppedCatches[I];
|
|
DEBUG(dbgs() << "Popped handler with state " << CH->getEHState() << "\n");
|
|
if (I + 1 == E || CH->getEHState() != PoppedCatches[I + 1]->getEHState()) {
|
|
int TryLow = CH->getEHState();
|
|
auto Handlers =
|
|
makeArrayRef(&PoppedCatches[LastTryLowIdx], I - LastTryLowIdx + 1);
|
|
DEBUG(dbgs() << "createTryBlockMapEntry(" << TryLow << ", " << TryHigh);
|
|
for (size_t J = 0; J < Handlers.size(); ++J) {
|
|
DEBUG(dbgs() << ", ");
|
|
print_name(Handlers[J]->getHandlerBlockOrFunc());
|
|
}
|
|
DEBUG(dbgs() << ")\n");
|
|
createTryBlockMapEntry(TryLow, TryHigh, Handlers);
|
|
LastTryLowIdx = I + 1;
|
|
}
|
|
}
|
|
|
|
for (CatchHandler *CH : PoppedCatches) {
|
|
if (auto *F = dyn_cast<Function>(CH->getHandlerBlockOrFunc())) {
|
|
if (FuncInfo.LastInvokeVisited[F]) {
|
|
DEBUG(dbgs() << "Assigning base state " << NextState << " to ");
|
|
print_name(F);
|
|
DEBUG(dbgs() << '\n');
|
|
FuncInfo.HandlerBaseState[F] = NextState;
|
|
DEBUG(dbgs() << "createUnwindMapEntry(" << currentEHNumber()
|
|
<< ", null)\n");
|
|
createUnwindMapEntry(currentEHNumber(), nullptr);
|
|
++NextState;
|
|
calculateStateNumbers(*F);
|
|
}
|
|
else {
|
|
DEBUG(dbgs() << "Deferring handling of ");
|
|
print_name(F);
|
|
DEBUG(dbgs() << " until last invoke visited.\n");
|
|
}
|
|
}
|
|
delete CH;
|
|
}
|
|
}
|
|
|
|
void WinEHNumbering::calculateStateNumbers(const Function &F) {
|
|
auto I = VisitedHandlers.insert(&F);
|
|
if (!I.second)
|
|
return; // We've already visited this handler, don't renumber it.
|
|
|
|
int OldBaseState = CurrentBaseState;
|
|
if (FuncInfo.HandlerBaseState.count(&F)) {
|
|
CurrentBaseState = FuncInfo.HandlerBaseState[&F];
|
|
}
|
|
|
|
size_t SavedHandlerStackSize = HandlerStack.size();
|
|
|
|
DEBUG(dbgs() << "Calculating state numbers for: " << F.getName() << '\n');
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
|
|
for (const BasicBlock &BB : F) {
|
|
for (const Instruction &I : BB) {
|
|
const auto *CI = dyn_cast<CallInst>(&I);
|
|
if (!CI || CI->doesNotThrow())
|
|
continue;
|
|
processCallSite(None, CI);
|
|
}
|
|
const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
|
|
if (!II)
|
|
continue;
|
|
const LandingPadInst *LPI = II->getLandingPadInst();
|
|
auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
|
|
if (!ActionsCall)
|
|
continue;
|
|
assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
|
|
parseEHActions(ActionsCall, ActionList);
|
|
if (ActionList.empty())
|
|
continue;
|
|
processCallSite(ActionList, II);
|
|
ActionList.clear();
|
|
FuncInfo.LandingPadStateMap[LPI] = currentEHNumber();
|
|
DEBUG(dbgs() << "Assigning state " << currentEHNumber()
|
|
<< " to landing pad at " << LPI->getParent()->getName()
|
|
<< '\n');
|
|
}
|
|
|
|
// Pop any actions that were pushed on the stack for this function.
|
|
popUnmatchedActions(SavedHandlerStackSize);
|
|
|
|
DEBUG(dbgs() << "Assigning max state " << NextState - 1
|
|
<< " to " << F.getName() << '\n');
|
|
FuncInfo.CatchHandlerMaxState[&F] = NextState - 1;
|
|
|
|
CurrentBaseState = OldBaseState;
|
|
}
|
|
|
|
// This function follows the same basic traversal as calculateStateNumbers
|
|
// but it is necessary to identify the root landing pad associated
|
|
// with each action before we start assigning state numbers.
|
|
void WinEHNumbering::findActionRootLPads(const Function &F) {
|
|
auto I = VisitedHandlers.insert(&F);
|
|
if (!I.second)
|
|
return; // We've already visited this handler, don't revisit it.
|
|
|
|
SmallVector<std::unique_ptr<ActionHandler>, 4> ActionList;
|
|
for (const BasicBlock &BB : F) {
|
|
const auto *II = dyn_cast<InvokeInst>(BB.getTerminator());
|
|
if (!II)
|
|
continue;
|
|
const LandingPadInst *LPI = II->getLandingPadInst();
|
|
auto *ActionsCall = dyn_cast<IntrinsicInst>(LPI->getNextNode());
|
|
if (!ActionsCall)
|
|
continue;
|
|
|
|
assert(ActionsCall->getIntrinsicID() == Intrinsic::eh_actions);
|
|
parseEHActions(ActionsCall, ActionList);
|
|
if (ActionList.empty())
|
|
continue;
|
|
for (int I = 0, E = ActionList.size(); I < E; ++I) {
|
|
if (auto *Handler
|
|
= dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc())) {
|
|
FuncInfo.LastInvoke[Handler] = II;
|
|
// Don't replace the root landing pad if we previously saw this
|
|
// handler in a different function.
|
|
if (FuncInfo.RootLPad.count(Handler) &&
|
|
FuncInfo.RootLPad[Handler]->getParent()->getParent() != &F)
|
|
continue;
|
|
DEBUG(dbgs() << "Setting root lpad for ");
|
|
print_name(Handler);
|
|
DEBUG(dbgs() << " to " << LPI->getParent()->getName() << '\n');
|
|
FuncInfo.RootLPad[Handler] = LPI;
|
|
}
|
|
}
|
|
// Walk the actions again and look for nested handlers. This has to
|
|
// happen after all of the actions have been processed in the current
|
|
// function.
|
|
for (int I = 0, E = ActionList.size(); I < E; ++I)
|
|
if (auto *Handler
|
|
= dyn_cast<Function>(ActionList[I]->getHandlerBlockOrFunc()))
|
|
findActionRootLPads(*Handler);
|
|
ActionList.clear();
|
|
}
|
|
}
|
|
|
|
void llvm::calculateWinCXXEHStateNumbers(const Function *ParentFn,
|
|
WinEHFuncInfo &FuncInfo) {
|
|
// Return if it's already been done.
|
|
if (!FuncInfo.LandingPadStateMap.empty())
|
|
return;
|
|
|
|
WinEHNumbering Num(FuncInfo);
|
|
Num.findActionRootLPads(*ParentFn);
|
|
// The VisitedHandlers list is used by both findActionRootLPads and
|
|
// calculateStateNumbers, but both functions need to visit all handlers.
|
|
Num.VisitedHandlers.clear();
|
|
Num.calculateStateNumbers(*ParentFn);
|
|
// Pop everything on the handler stack.
|
|
// It may be necessary to call this more than once because a handler can
|
|
// be pushed on the stack as a result of clearing the stack.
|
|
while (!Num.HandlerStack.empty())
|
|
Num.processCallSite(None, ImmutableCallSite());
|
|
}
|