mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-15 20:29:48 +00:00
f96076ed80
The way we split SEH catch-all blocks can leave some dead EH values behind at -O0. Try to remove them, and if we fail, replace them all with undef. Fixes a crash when removing the old unreachable landingpad which is still used by extractvalue instructions in the catch-all block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235061 91177308-0d34-0410-b5e6-96231b3b80d8
1737 lines
71 KiB
C++
1737 lines
71 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. It snifs the personality function to see which kind of
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// preparation is necessary. If the personality function uses the Itanium LSDA,
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// this pass delegates to the DWARF EH preparation pass.
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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/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/CommandLine.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), DT(nullptr) {}
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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 promoteLandingPadValues(LandingPadInst *LPad);
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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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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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// All fields are reset by runOnFunction.
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DominatorTree *DT;
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EHPersonality Personality;
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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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// 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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};
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class WinEHFrameVariableMaterializer : public ValueMaterializer {
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public:
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WinEHFrameVariableMaterializer(Function *OutlinedFn,
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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, FrameVarInfoMap &VarInfo,
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LandingPadMap &LPadMap)
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: Materializer(HandlerFn, 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) {}
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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 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 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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};
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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 *Selector, FrameVarInfoMap &VarInfo,
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LandingPadMap &LPadMap,
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DenseMap<LandingPadInst *, const LandingPadInst *> &NestedLPads)
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: WinEHCloningDirectorBase(CatchFn, VarInfo, LPadMap),
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CurrentSelector(Selector->stripPointerCasts()),
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ExceptionObjectVar(nullptr), NestedLPtoOriginalLP(NestedLPads) {}
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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 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 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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};
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class WinEHCleanupDirector : public WinEHCloningDirectorBase {
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public:
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WinEHCleanupDirector(Function *CleanupFn, FrameVarInfoMap &VarInfo,
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LandingPadMap &LPadMap)
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: WinEHCloningDirectorBase(CleanupFn, VarInfo, 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 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 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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// FIXME: Remove this once the backend can handle the prepared IR.
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static cl::opt<bool>
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SEHPrepare("sehprepare", cl::Hidden,
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cl::desc("Prepare functions with SEH personalities"));
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bool WinEHPrepare::runOnFunction(Function &Fn) {
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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 (isAsynchronousEHPersonality(Personality) && !SEHPrepare) {
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// Replace all resume instructions with unreachable.
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// FIXME: Remove this once the backend can handle the prepared IR.
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for (ResumeInst *Resume : Resumes) {
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IRBuilder<>(Resume).CreateUnreachable();
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Resume->eraseFromParent();
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}
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return true;
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}
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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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bool WinEHPrepare::prepareExceptionHandlers(
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Function &F, SmallVectorImpl<LandingPadInst *> &LPads) {
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// These containers are used to re-map frame variables that are used in
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// outlined catch and cleanup handlers. They will be populated as the
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// handlers are outlined.
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FrameVarInfoMap FrameVarInfo;
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bool HandlersOutlined = false;
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Module *M = F.getParent();
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LLVMContext &Context = M->getContext();
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// Create a new function to receive the handler contents.
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PointerType *Int8PtrType = Type::getInt8PtrTy(Context);
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Type *Int32Type = Type::getInt32Ty(Context);
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Function *ActionIntrin = Intrinsic::getDeclaration(M, Intrinsic::eh_actions);
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for (LandingPadInst *LPad : LPads) {
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// Look for evidence that this landingpad has already been processed.
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bool LPadHasActionList = false;
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BasicBlock *LPadBB = LPad->getParent();
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for (Instruction &Inst : *LPadBB) {
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if (auto *IntrinCall = dyn_cast<IntrinsicInst>(&Inst)) {
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if (IntrinCall->getIntrinsicID() == Intrinsic::eh_actions) {
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LPadHasActionList = true;
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break;
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}
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}
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// FIXME: This is here to help with the development of nested landing pad
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// outlining. It should be removed when that is finished.
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if (isa<UnreachableInst>(Inst)) {
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LPadHasActionList = true;
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break;
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}
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}
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// If we've already outlined the handlers for this landingpad,
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// there's nothing more to do here.
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if (LPadHasActionList)
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continue;
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// If either of the values in the aggregate returned by the landing pad is
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// extracted and stored to memory, promote the stored value to a register.
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promoteLandingPadValues(LPad);
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LandingPadActions Actions;
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mapLandingPadBlocks(LPad, Actions);
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HandlersOutlined |= !Actions.actions().empty();
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for (ActionHandler *Action : Actions) {
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if (Action->hasBeenProcessed())
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continue;
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BasicBlock *StartBB = Action->getStartBlock();
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// SEH doesn't do any outlining for catches. Instead, pass the handler
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// basic block addr to llvm.eh.actions and list the block as a return
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// target.
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if (isAsynchronousEHPersonality(Personality)) {
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if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
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processSEHCatchHandler(CatchAction, StartBB);
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continue;
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}
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}
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outlineHandler(Action, &F, LPad, StartBB, FrameVarInfo);
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}
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// Replace the landing pad with a new llvm.eh.action based landing pad.
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BasicBlock *NewLPadBB = BasicBlock::Create(Context, "lpad", &F, LPadBB);
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assert(!isa<PHINode>(LPadBB->begin()));
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auto *NewLPad = cast<LandingPadInst>(LPad->clone());
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NewLPadBB->getInstList().push_back(NewLPad);
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while (!pred_empty(LPadBB)) {
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auto *pred = *pred_begin(LPadBB);
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InvokeInst *Invoke = cast<InvokeInst>(pred->getTerminator());
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Invoke->setUnwindDest(NewLPadBB);
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}
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// If anyone is still using the old landingpad value, just give them undef
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// instead. The eh pointer and selector values are not real.
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LPad->replaceAllUsesWith(UndefValue::get(LPad->getType()));
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// Replace the mapping of any nested landing pad that previously mapped
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// to this landing pad with a referenced to the cloned version.
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for (auto &LPadPair : NestedLPtoOriginalLP) {
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const LandingPadInst *OriginalLPad = LPadPair.second;
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if (OriginalLPad == LPad) {
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LPadPair.second = NewLPad;
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}
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}
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// Replace uses of the old lpad in phis with this block and delete the old
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// block.
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LPadBB->replaceSuccessorsPhiUsesWith(NewLPadBB);
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LPadBB->getTerminator()->eraseFromParent();
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new UnreachableInst(LPadBB->getContext(), LPadBB);
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// Add a call to describe the actions for this landing pad.
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std::vector<Value *> ActionArgs;
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for (ActionHandler *Action : Actions) {
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// Action codes from docs are: 0 cleanup, 1 catch.
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if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
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ActionArgs.push_back(ConstantInt::get(Int32Type, 1));
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ActionArgs.push_back(CatchAction->getSelector());
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// Find the frame escape index of the exception object alloca in the
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// parent.
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int FrameEscapeIdx = -1;
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Value *EHObj = const_cast<Value *>(CatchAction->getExceptionVar());
|
|
if (EHObj && !isa<ConstantPointerNull>(EHObj)) {
|
|
auto I = FrameVarInfo.find(EHObj);
|
|
assert(I != FrameVarInfo.end() &&
|
|
"failed to map llvm.eh.begincatch var");
|
|
FrameEscapeIdx = std::distance(FrameVarInfo.begin(), I);
|
|
}
|
|
ActionArgs.push_back(ConstantInt::get(Int32Type, FrameEscapeIdx));
|
|
} else {
|
|
ActionArgs.push_back(ConstantInt::get(Int32Type, 0));
|
|
}
|
|
ActionArgs.push_back(Action->getHandlerBlockOrFunc());
|
|
}
|
|
CallInst *Recover =
|
|
CallInst::Create(ActionIntrin, ActionArgs, "recover", NewLPadBB);
|
|
|
|
// Add an indirect branch listing possible successors of the catch handlers.
|
|
IndirectBrInst *Branch = IndirectBrInst::Create(Recover, 0, NewLPadBB);
|
|
for (ActionHandler *Action : Actions) {
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
for (auto *Target : CatchAction->getReturnTargets()) {
|
|
Branch->addDestination(Target);
|
|
}
|
|
}
|
|
}
|
|
} // End for each landingpad
|
|
|
|
// If nothing got outlined, there is no more processing to be done.
|
|
if (!HandlersOutlined)
|
|
return false;
|
|
|
|
// Replace any nested landing pad stubs with the correct action handler.
|
|
// This must be done before we remove unreachable blocks because it
|
|
// cleans up references to outlined blocks that will be deleted.
|
|
for (auto &LPadPair : NestedLPtoOriginalLP)
|
|
completeNestedLandingPad(&F, LPadPair.first, LPadPair.second, FrameVarInfo);
|
|
NestedLPtoOriginalLP.clear();
|
|
|
|
F.addFnAttr("wineh-parent", F.getName());
|
|
|
|
// Delete any blocks that were only used by handlers that were outlined above.
|
|
removeUnreachableBlocks(F);
|
|
|
|
BasicBlock *Entry = &F.getEntryBlock();
|
|
IRBuilder<> Builder(F.getParent()->getContext());
|
|
Builder.SetInsertPoint(Entry->getFirstInsertionPt());
|
|
|
|
Function *FrameEscapeFn =
|
|
Intrinsic::getDeclaration(M, Intrinsic::frameescape);
|
|
Function *RecoverFrameFn =
|
|
Intrinsic::getDeclaration(M, Intrinsic::framerecover);
|
|
|
|
// Finally, replace all of the temporary allocas for frame variables used in
|
|
// the outlined handlers with calls to llvm.framerecover.
|
|
BasicBlock::iterator II = Entry->getFirstInsertionPt();
|
|
Instruction *AllocaInsertPt = II;
|
|
SmallVector<Value *, 8> AllocasToEscape;
|
|
for (auto &VarInfoEntry : FrameVarInfo) {
|
|
Value *ParentVal = VarInfoEntry.first;
|
|
TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second;
|
|
|
|
// If the mapped value isn't already an alloca, we need to spill it if it
|
|
// is a computed value or copy it if it is an argument.
|
|
AllocaInst *ParentAlloca = dyn_cast<AllocaInst>(ParentVal);
|
|
if (!ParentAlloca) {
|
|
if (auto *Arg = dyn_cast<Argument>(ParentVal)) {
|
|
// Lower this argument to a copy and then demote that to the stack.
|
|
// We can't just use the argument location because the handler needs
|
|
// it to be in the frame allocation block.
|
|
// Use 'select i8 true, %arg, undef' to simulate a 'no-op' instruction.
|
|
Value *TrueValue = ConstantInt::getTrue(Context);
|
|
Value *UndefValue = UndefValue::get(Arg->getType());
|
|
Instruction *SI =
|
|
SelectInst::Create(TrueValue, Arg, UndefValue,
|
|
Arg->getName() + ".tmp", AllocaInsertPt);
|
|
Arg->replaceAllUsesWith(SI);
|
|
// Reset the select operand, because it was clobbered by the RAUW above.
|
|
SI->setOperand(1, Arg);
|
|
ParentAlloca = DemoteRegToStack(*SI, true, SI);
|
|
} else if (auto *PN = dyn_cast<PHINode>(ParentVal)) {
|
|
ParentAlloca = DemotePHIToStack(PN, AllocaInsertPt);
|
|
} else {
|
|
Instruction *ParentInst = cast<Instruction>(ParentVal);
|
|
// FIXME: This is a work-around to temporarily handle the case where an
|
|
// instruction that is only used in handlers is not sunk.
|
|
// Without uses, DemoteRegToStack would just eliminate the value.
|
|
// This will fail if ParentInst is an invoke.
|
|
if (ParentInst->getNumUses() == 0) {
|
|
BasicBlock::iterator InsertPt = ParentInst;
|
|
++InsertPt;
|
|
ParentAlloca =
|
|
new AllocaInst(ParentInst->getType(), nullptr,
|
|
ParentInst->getName() + ".reg2mem",
|
|
AllocaInsertPt);
|
|
new StoreInst(ParentInst, ParentAlloca, InsertPt);
|
|
} else {
|
|
ParentAlloca = DemoteRegToStack(*ParentInst, true, AllocaInsertPt);
|
|
}
|
|
}
|
|
}
|
|
|
|
// FIXME: We should try to sink unescaped allocas from the parent frame into
|
|
// the child frame. If the alloca is escaped, we have to use the lifetime
|
|
// markers to ensure that the alloca is only live within the child frame.
|
|
|
|
// Add this alloca to the list of things to escape.
|
|
AllocasToEscape.push_back(ParentAlloca);
|
|
|
|
// Next replace all outlined allocas that are mapped to it.
|
|
for (AllocaInst *TempAlloca : Allocas) {
|
|
if (TempAlloca == getCatchObjectSentinel())
|
|
continue; // Skip catch parameter sentinels.
|
|
Function *HandlerFn = TempAlloca->getParent()->getParent();
|
|
// FIXME: Sink this GEP into the blocks where it is used.
|
|
Builder.SetInsertPoint(TempAlloca);
|
|
Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc());
|
|
Value *RecoverArgs[] = {
|
|
Builder.CreateBitCast(&F, Int8PtrType, ""),
|
|
&(HandlerFn->getArgumentList().back()),
|
|
llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)};
|
|
Value *RecoveredAlloca = Builder.CreateCall(RecoverFrameFn, RecoverArgs);
|
|
// Add a pointer bitcast if the alloca wasn't an i8.
|
|
if (RecoveredAlloca->getType() != TempAlloca->getType()) {
|
|
RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8");
|
|
RecoveredAlloca =
|
|
Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType());
|
|
}
|
|
TempAlloca->replaceAllUsesWith(RecoveredAlloca);
|
|
TempAlloca->removeFromParent();
|
|
RecoveredAlloca->takeName(TempAlloca);
|
|
delete TempAlloca;
|
|
}
|
|
} // End for each FrameVarInfo entry.
|
|
|
|
// Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry
|
|
// block.
|
|
Builder.SetInsertPoint(&F.getEntryBlock().back());
|
|
Builder.CreateCall(FrameEscapeFn, AllocasToEscape);
|
|
|
|
// Clean up the handler action maps we created for this function
|
|
DeleteContainerSeconds(CatchHandlerMap);
|
|
CatchHandlerMap.clear();
|
|
DeleteContainerSeconds(CleanupHandlerMap);
|
|
CleanupHandlerMap.clear();
|
|
|
|
return HandlersOutlined;
|
|
}
|
|
|
|
void WinEHPrepare::promoteLandingPadValues(LandingPadInst *LPad) {
|
|
// If the return values of the landing pad instruction are extracted and
|
|
// stored to memory, we want to promote the store locations to reg values.
|
|
SmallVector<AllocaInst *, 2> EHAllocas;
|
|
|
|
// The landingpad instruction returns an aggregate value. Typically, its
|
|
// value will be passed to a pair of extract value instructions and the
|
|
// results of those extracts are often passed to store instructions.
|
|
// In unoptimized code the stored value will often be loaded and then stored
|
|
// again.
|
|
for (auto *U : LPad->users()) {
|
|
ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
|
|
if (!Extract)
|
|
continue;
|
|
|
|
for (auto *EU : Extract->users()) {
|
|
if (auto *Store = dyn_cast<StoreInst>(EU)) {
|
|
auto *AV = cast<AllocaInst>(Store->getPointerOperand());
|
|
EHAllocas.push_back(AV);
|
|
}
|
|
}
|
|
}
|
|
|
|
// We can't do this without a dominator tree.
|
|
assert(DT);
|
|
|
|
if (!EHAllocas.empty()) {
|
|
PromoteMemToReg(EHAllocas, *DT);
|
|
EHAllocas.clear();
|
|
}
|
|
|
|
// After promotion, some extracts may be trivially dead. Remove them.
|
|
SmallVector<Value *, 4> Users(LPad->user_begin(), LPad->user_end());
|
|
for (auto *U : Users)
|
|
RecursivelyDeleteTriviallyDeadInstructions(U);
|
|
}
|
|
|
|
void WinEHPrepare::completeNestedLandingPad(Function *ParentFn,
|
|
LandingPadInst *OutlinedLPad,
|
|
const LandingPadInst *OriginalLPad,
|
|
FrameVarInfoMap &FrameVarInfo) {
|
|
// Get the nested block and erase the unreachable instruction that was
|
|
// temporarily inserted as its terminator.
|
|
LLVMContext &Context = ParentFn->getContext();
|
|
BasicBlock *OutlinedBB = OutlinedLPad->getParent();
|
|
assert(isa<UnreachableInst>(OutlinedBB->getTerminator()));
|
|
OutlinedBB->getTerminator()->eraseFromParent();
|
|
// That should leave OutlinedLPad as the last instruction in its block.
|
|
assert(&OutlinedBB->back() == OutlinedLPad);
|
|
|
|
// The original landing pad will have already had its action intrinsic
|
|
// built by the outlining loop. We need to clone that into the outlined
|
|
// location. It may also be necessary to add references to the exception
|
|
// variables to the outlined handler in which this landing pad is nested
|
|
// and remap return instructions in the nested handlers that should return
|
|
// to an address in the outlined handler.
|
|
Function *OutlinedHandlerFn = OutlinedBB->getParent();
|
|
BasicBlock::const_iterator II = OriginalLPad;
|
|
++II;
|
|
// The instruction after the landing pad should now be a call to eh.actions.
|
|
const Instruction *Recover = II;
|
|
assert(match(Recover, m_Intrinsic<Intrinsic::eh_actions>()));
|
|
IntrinsicInst *EHActions = cast<IntrinsicInst>(Recover->clone());
|
|
|
|
// Remap the exception variables into the outlined function.
|
|
WinEHFrameVariableMaterializer Materializer(OutlinedHandlerFn, FrameVarInfo);
|
|
SmallVector<BlockAddress *, 4> ActionTargets;
|
|
SmallVector<ActionHandler *, 4> ActionList;
|
|
parseEHActions(EHActions, ActionList);
|
|
for (auto *Action : ActionList) {
|
|
auto *Catch = dyn_cast<CatchHandler>(Action);
|
|
if (!Catch)
|
|
continue;
|
|
// The dyn_cast to function here selects C++ catch handlers and skips
|
|
// SEH catch handlers.
|
|
auto *Handler = dyn_cast<Function>(Catch->getHandlerBlockOrFunc());
|
|
if (!Handler)
|
|
continue;
|
|
// Visit all the return instructions, looking for places that return
|
|
// to a location within OutlinedHandlerFn.
|
|
for (BasicBlock &NestedHandlerBB : *Handler) {
|
|
auto *Ret = dyn_cast<ReturnInst>(NestedHandlerBB.getTerminator());
|
|
if (!Ret)
|
|
continue;
|
|
|
|
// Handler functions must always return a block address.
|
|
BlockAddress *BA = cast<BlockAddress>(Ret->getReturnValue());
|
|
// The original target will have been in the main parent function,
|
|
// but if it is the address of a block that has been outlined, it
|
|
// should be a block that was outlined into OutlinedHandlerFn.
|
|
assert(BA->getFunction() == ParentFn);
|
|
|
|
// Ignore targets that aren't part of OutlinedHandlerFn.
|
|
if (!LPadTargetBlocks.count(BA->getBasicBlock()))
|
|
continue;
|
|
|
|
// If the return value is the address ofF a block that we
|
|
// previously outlined into the parent handler function, replace
|
|
// the return instruction and add the mapped target to the list
|
|
// of possible return addresses.
|
|
BasicBlock *MappedBB = LPadTargetBlocks[BA->getBasicBlock()];
|
|
assert(MappedBB->getParent() == OutlinedHandlerFn);
|
|
BlockAddress *NewBA = BlockAddress::get(OutlinedHandlerFn, MappedBB);
|
|
Ret->eraseFromParent();
|
|
ReturnInst::Create(Context, NewBA, &NestedHandlerBB);
|
|
ActionTargets.push_back(NewBA);
|
|
}
|
|
}
|
|
DeleteContainerPointers(ActionList);
|
|
ActionList.clear();
|
|
OutlinedBB->getInstList().push_back(EHActions);
|
|
|
|
// Insert an indirect branch into the outlined landing pad BB.
|
|
IndirectBrInst *IBr = IndirectBrInst::Create(EHActions, 0, OutlinedBB);
|
|
// Add the previously collected action targets.
|
|
for (auto *Target : ActionTargets)
|
|
IBr->addDestination(Target->getBasicBlock());
|
|
}
|
|
|
|
// This function examines a block to determine whether the block ends with a
|
|
// conditional branch to a catch handler based on a selector comparison.
|
|
// This function is used both by the WinEHPrepare::findSelectorComparison() and
|
|
// WinEHCleanupDirector::handleTypeIdFor().
|
|
static bool isSelectorDispatch(BasicBlock *BB, BasicBlock *&CatchHandler,
|
|
Constant *&Selector, BasicBlock *&NextBB) {
|
|
ICmpInst::Predicate Pred;
|
|
BasicBlock *TBB, *FBB;
|
|
Value *LHS, *RHS;
|
|
|
|
if (!match(BB->getTerminator(),
|
|
m_Br(m_ICmp(Pred, m_Value(LHS), m_Value(RHS)), TBB, FBB)))
|
|
return false;
|
|
|
|
if (!match(LHS,
|
|
m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))) &&
|
|
!match(RHS, m_Intrinsic<Intrinsic::eh_typeid_for>(m_Constant(Selector))))
|
|
return false;
|
|
|
|
if (Pred == CmpInst::ICMP_EQ) {
|
|
CatchHandler = TBB;
|
|
NextBB = FBB;
|
|
return true;
|
|
}
|
|
|
|
if (Pred == CmpInst::ICMP_NE) {
|
|
CatchHandler = FBB;
|
|
NextBB = TBB;
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static BasicBlock *createStubLandingPad(Function *Handler,
|
|
Value *PersonalityFn) {
|
|
// FIXME: Finish this!
|
|
LLVMContext &Context = Handler->getContext();
|
|
BasicBlock *StubBB = BasicBlock::Create(Context, "stub");
|
|
Handler->getBasicBlockList().push_back(StubBB);
|
|
IRBuilder<> Builder(StubBB);
|
|
LandingPadInst *LPad = Builder.CreateLandingPad(
|
|
llvm::StructType::get(Type::getInt8PtrTy(Context),
|
|
Type::getInt32Ty(Context), nullptr),
|
|
PersonalityFn, 0);
|
|
LPad->setCleanup(true);
|
|
Builder.CreateUnreachable();
|
|
return StubBB;
|
|
}
|
|
|
|
// Cycles through the blocks in an outlined handler function looking for an
|
|
// invoke instruction and inserts an invoke of llvm.donothing with an empty
|
|
// landing pad if none is found. The code that generates the .xdata tables for
|
|
// the handler needs at least one landing pad to identify the parent function's
|
|
// personality.
|
|
void WinEHPrepare::addStubInvokeToHandlerIfNeeded(Function *Handler,
|
|
Value *PersonalityFn) {
|
|
ReturnInst *Ret = nullptr;
|
|
for (BasicBlock &BB : *Handler) {
|
|
TerminatorInst *Terminator = BB.getTerminator();
|
|
// If we find an invoke, there is nothing to be done.
|
|
auto *II = dyn_cast<InvokeInst>(Terminator);
|
|
if (II)
|
|
return;
|
|
// If we've already recorded a return instruction, keep looking for invokes.
|
|
if (Ret)
|
|
continue;
|
|
// If we haven't recorded a return instruction yet, try this terminator.
|
|
Ret = dyn_cast<ReturnInst>(Terminator);
|
|
}
|
|
|
|
// If we got this far, the handler contains no invokes. We should have seen
|
|
// at least one return. We'll insert an invoke of llvm.donothing ahead of
|
|
// that return.
|
|
assert(Ret);
|
|
BasicBlock *OldRetBB = Ret->getParent();
|
|
BasicBlock *NewRetBB = SplitBlock(OldRetBB, Ret);
|
|
// SplitBlock adds an unconditional branch instruction at the end of the
|
|
// parent block. We want to replace that with an invoke call, so we can
|
|
// erase it now.
|
|
OldRetBB->getTerminator()->eraseFromParent();
|
|
BasicBlock *StubLandingPad = createStubLandingPad(Handler, PersonalityFn);
|
|
Function *F =
|
|
Intrinsic::getDeclaration(Handler->getParent(), Intrinsic::donothing);
|
|
InvokeInst::Create(F, NewRetBB, StubLandingPad, None, "", OldRetBB);
|
|
}
|
|
|
|
bool WinEHPrepare::outlineHandler(ActionHandler *Action, Function *SrcFn,
|
|
LandingPadInst *LPad, BasicBlock *StartBB,
|
|
FrameVarInfoMap &VarInfo) {
|
|
Module *M = SrcFn->getParent();
|
|
LLVMContext &Context = M->getContext();
|
|
|
|
// Create a new function to receive the handler contents.
|
|
Type *Int8PtrType = Type::getInt8PtrTy(Context);
|
|
std::vector<Type *> ArgTys;
|
|
ArgTys.push_back(Int8PtrType);
|
|
ArgTys.push_back(Int8PtrType);
|
|
Function *Handler;
|
|
if (Action->getType() == Catch) {
|
|
FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false);
|
|
Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
|
|
SrcFn->getName() + ".catch", M);
|
|
} else {
|
|
FunctionType *FnType =
|
|
FunctionType::get(Type::getVoidTy(Context), ArgTys, false);
|
|
Handler = Function::Create(FnType, GlobalVariable::InternalLinkage,
|
|
SrcFn->getName() + ".cleanup", M);
|
|
}
|
|
|
|
Handler->addFnAttr("wineh-parent", SrcFn->getName());
|
|
|
|
// Generate a standard prolog to setup the frame recovery structure.
|
|
IRBuilder<> Builder(Context);
|
|
BasicBlock *Entry = BasicBlock::Create(Context, "entry");
|
|
Handler->getBasicBlockList().push_front(Entry);
|
|
Builder.SetInsertPoint(Entry);
|
|
Builder.SetCurrentDebugLocation(LPad->getDebugLoc());
|
|
|
|
std::unique_ptr<WinEHCloningDirectorBase> Director;
|
|
|
|
ValueToValueMapTy VMap;
|
|
|
|
LandingPadMap &LPadMap = LPadMaps[LPad];
|
|
if (!LPadMap.isInitialized())
|
|
LPadMap.mapLandingPad(LPad);
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
Constant *Sel = CatchAction->getSelector();
|
|
Director.reset(new WinEHCatchDirector(Handler, Sel, VarInfo, LPadMap,
|
|
NestedLPtoOriginalLP));
|
|
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
|
|
ConstantInt::get(Type::getInt32Ty(Context), 1));
|
|
} else {
|
|
Director.reset(new WinEHCleanupDirector(Handler, VarInfo, LPadMap));
|
|
LPadMap.remapEHValues(VMap, UndefValue::get(Int8PtrType),
|
|
UndefValue::get(Type::getInt32Ty(Context)));
|
|
}
|
|
|
|
SmallVector<ReturnInst *, 8> Returns;
|
|
ClonedCodeInfo OutlinedFunctionInfo;
|
|
|
|
// If the start block contains PHI nodes, we need to map them.
|
|
BasicBlock::iterator II = StartBB->begin();
|
|
while (auto *PN = dyn_cast<PHINode>(II)) {
|
|
bool Mapped = false;
|
|
// Look for PHI values that we have already mapped (such as the selector).
|
|
for (Value *Val : PN->incoming_values()) {
|
|
if (VMap.count(Val)) {
|
|
VMap[PN] = VMap[Val];
|
|
Mapped = true;
|
|
}
|
|
}
|
|
// If we didn't find a match for this value, map it as an undef.
|
|
if (!Mapped) {
|
|
VMap[PN] = UndefValue::get(PN->getType());
|
|
}
|
|
++II;
|
|
}
|
|
|
|
// Skip over PHIs and, if applicable, landingpad instructions.
|
|
II = StartBB->getFirstInsertionPt();
|
|
|
|
CloneAndPruneIntoFromInst(Handler, SrcFn, II, VMap,
|
|
/*ModuleLevelChanges=*/false, Returns, "",
|
|
&OutlinedFunctionInfo, Director.get());
|
|
|
|
// Move all the instructions in the first cloned block into our entry block.
|
|
BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry));
|
|
Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList());
|
|
FirstClonedBB->eraseFromParent();
|
|
|
|
// Make sure we can identify the handler's personality later.
|
|
addStubInvokeToHandlerIfNeeded(Handler, LPad->getPersonalityFn());
|
|
|
|
if (auto *CatchAction = dyn_cast<CatchHandler>(Action)) {
|
|
WinEHCatchDirector *CatchDirector =
|
|
reinterpret_cast<WinEHCatchDirector *>(Director.get());
|
|
CatchAction->setExceptionVar(CatchDirector->getExceptionVar());
|
|
CatchAction->setReturnTargets(CatchDirector->getReturnTargets());
|
|
|
|
// Look for blocks that are not part of the landing pad that we just
|
|
// outlined but terminate with a call to llvm.eh.endcatch and a
|
|
// branch to a block that is in the handler we just outlined.
|
|
// These blocks will be part of a nested landing pad that intends to
|
|
// return to an address in this handler. This case is best handled
|
|
// after both landing pads have been outlined, so for now we'll just
|
|
// save the association of the blocks in LPadTargetBlocks. The
|
|
// return instructions which are created from these branches will be
|
|
// replaced after all landing pads have been outlined.
|
|
for (const auto MapEntry : VMap) {
|
|
// VMap maps all values and blocks that were just cloned, but dead
|
|
// blocks which were pruned will map to nullptr.
|
|
if (!isa<BasicBlock>(MapEntry.first) || MapEntry.second == nullptr)
|
|
continue;
|
|
const BasicBlock *MappedBB = cast<BasicBlock>(MapEntry.first);
|
|
for (auto *Pred : predecessors(const_cast<BasicBlock *>(MappedBB))) {
|
|
auto *Branch = dyn_cast<BranchInst>(Pred->getTerminator());
|
|
if (!Branch || !Branch->isUnconditional() || Pred->size() <= 1)
|
|
continue;
|
|
BasicBlock::iterator II = const_cast<BranchInst *>(Branch);
|
|
--II;
|
|
if (match(cast<Value>(II), m_Intrinsic<Intrinsic::eh_endcatch>())) {
|
|
// This would indicate that a nested landing pad wants to return
|
|
// to a block that is outlined into two different handlers.
|
|
assert(!LPadTargetBlocks.count(MappedBB));
|
|
LPadTargetBlocks[MappedBB] = cast<BasicBlock>(MapEntry.second);
|
|
}
|
|
}
|
|
}
|
|
} // End if (CatchAction)
|
|
|
|
Action->setHandlerBlockOrFunc(Handler);
|
|
|
|
return true;
|
|
}
|
|
|
|
/// This BB must end in a selector dispatch. All we need to do is pass the
|
|
/// handler block to llvm.eh.actions and list it as a possible indirectbr
|
|
/// target.
|
|
void WinEHPrepare::processSEHCatchHandler(CatchHandler *CatchAction,
|
|
BasicBlock *StartBB) {
|
|
BasicBlock *HandlerBB;
|
|
BasicBlock *NextBB;
|
|
Constant *Selector;
|
|
bool Res = isSelectorDispatch(StartBB, HandlerBB, Selector, NextBB);
|
|
if (Res) {
|
|
// If this was EH dispatch, this must be a conditional branch to the handler
|
|
// block.
|
|
// FIXME: Handle instructions in the dispatch block. Currently we drop them,
|
|
// leading to crashes if some optimization hoists stuff here.
|
|
assert(CatchAction->getSelector() && HandlerBB &&
|
|
"expected catch EH dispatch");
|
|
} else {
|
|
// This must be a catch-all. Split the block after the landingpad.
|
|
assert(CatchAction->getSelector()->isNullValue() && "expected catch-all");
|
|
HandlerBB =
|
|
StartBB->splitBasicBlock(StartBB->getFirstInsertionPt(), "catch.all");
|
|
}
|
|
CatchAction->setHandlerBlockOrFunc(BlockAddress::get(HandlerBB));
|
|
TinyPtrVector<BasicBlock *> Targets(HandlerBB);
|
|
CatchAction->setReturnTargets(Targets);
|
|
}
|
|
|
|
void LandingPadMap::mapLandingPad(const LandingPadInst *LPad) {
|
|
// Each instance of this class should only ever be used to map a single
|
|
// landing pad.
|
|
assert(OriginLPad == nullptr || OriginLPad == LPad);
|
|
|
|
// If the landing pad has already been mapped, there's nothing more to do.
|
|
if (OriginLPad == LPad)
|
|
return;
|
|
|
|
OriginLPad = LPad;
|
|
|
|
// The landingpad instruction returns an aggregate value. Typically, its
|
|
// value will be passed to a pair of extract value instructions and the
|
|
// results of those extracts will have been promoted to reg values before
|
|
// this routine is called.
|
|
for (auto *U : LPad->users()) {
|
|
const ExtractValueInst *Extract = dyn_cast<ExtractValueInst>(U);
|
|
if (!Extract)
|
|
continue;
|
|
assert(Extract->getNumIndices() == 1 &&
|
|
"Unexpected operation: extracting both landing pad values");
|
|
unsigned int Idx = *(Extract->idx_begin());
|
|
assert((Idx == 0 || Idx == 1) &&
|
|
"Unexpected operation: extracting an unknown landing pad element");
|
|
if (Idx == 0) {
|
|
ExtractedEHPtrs.push_back(Extract);
|
|
} else if (Idx == 1) {
|
|
ExtractedSelectors.push_back(Extract);
|
|
}
|
|
}
|
|
}
|
|
|
|
bool LandingPadMap::isOriginLandingPadBlock(const BasicBlock *BB) const {
|
|
return BB->getLandingPadInst() == OriginLPad;
|
|
}
|
|
|
|
bool LandingPadMap::isLandingPadSpecificInst(const Instruction *Inst) const {
|
|
if (Inst == OriginLPad)
|
|
return true;
|
|
for (auto *Extract : ExtractedEHPtrs) {
|
|
if (Inst == Extract)
|
|
return true;
|
|
}
|
|
for (auto *Extract : ExtractedSelectors) {
|
|
if (Inst == Extract)
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
void LandingPadMap::remapEHValues(ValueToValueMapTy &VMap, Value *EHPtrValue,
|
|
Value *SelectorValue) const {
|
|
// Remap all landing pad extract instructions to the specified values.
|
|
for (auto *Extract : ExtractedEHPtrs)
|
|
VMap[Extract] = EHPtrValue;
|
|
for (auto *Extract : ExtractedSelectors)
|
|
VMap[Extract] = SelectorValue;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// If this is one of the boilerplate landing pad instructions, skip it.
|
|
// The instruction will have already been remapped in VMap.
|
|
if (LPadMap.isLandingPadSpecificInst(Inst))
|
|
return CloningDirector::SkipInstruction;
|
|
|
|
// Nested landing pads will be cloned as stubs, with just the
|
|
// landingpad instruction and an unreachable instruction. When
|
|
// all landingpads have been outlined, we'll replace this with the
|
|
// llvm.eh.actions call and indirect branch created when the
|
|
// landing pad was outlined.
|
|
if (auto *LPad = dyn_cast<LandingPadInst>(Inst)) {
|
|
return handleLandingPad(VMap, LPad, NewBB);
|
|
}
|
|
|
|
if (auto *Invoke = dyn_cast<InvokeInst>(Inst))
|
|
return handleInvoke(VMap, Invoke, NewBB);
|
|
|
|
if (auto *Resume = dyn_cast<ResumeInst>(Inst))
|
|
return handleResume(VMap, Resume, NewBB);
|
|
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
|
|
return handleBeginCatch(VMap, Inst, NewBB);
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
|
|
return handleEndCatch(VMap, Inst, NewBB);
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
|
|
return handleTypeIdFor(VMap, Inst, NewBB);
|
|
|
|
// Continue with the default cloning behavior.
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleLandingPad(
|
|
ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
|
|
Instruction *NewInst = LPad->clone();
|
|
if (LPad->hasName())
|
|
NewInst->setName(LPad->getName());
|
|
// Save this correlation for later processing.
|
|
NestedLPtoOriginalLP[cast<LandingPadInst>(NewInst)] = LPad;
|
|
VMap[LPad] = NewInst;
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(NewInst);
|
|
InstList.push_back(new UnreachableInst(NewBB->getContext()));
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// The argument to the call is some form of the first element of the
|
|
// landingpad aggregate value, but that doesn't matter. It isn't used
|
|
// here.
|
|
// The second argument is an outparameter where the exception object will be
|
|
// stored. Typically the exception object is a scalar, but it can be an
|
|
// aggregate when catching by value.
|
|
// FIXME: Leave something behind to indicate where the exception object lives
|
|
// for this handler. Should it be part of llvm.eh.actions?
|
|
assert(ExceptionObjectVar == nullptr && "Multiple calls to "
|
|
"llvm.eh.begincatch found while "
|
|
"outlining catch handler.");
|
|
ExceptionObjectVar = Inst->getOperand(1)->stripPointerCasts();
|
|
if (isa<ConstantPointerNull>(ExceptionObjectVar))
|
|
return CloningDirector::SkipInstruction;
|
|
assert(cast<AllocaInst>(ExceptionObjectVar)->isStaticAlloca() &&
|
|
"catch parameter is not static alloca");
|
|
Materializer.escapeCatchObject(ExceptionObjectVar);
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap,
|
|
const Instruction *Inst, BasicBlock *NewBB) {
|
|
auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
|
|
// It might be interesting to track whether or not we are inside a catch
|
|
// function, but that might make the algorithm more brittle than it needs
|
|
// to be.
|
|
|
|
// The end catch call can occur in one of two places: either in a
|
|
// landingpad block that is part of the catch handlers exception mechanism,
|
|
// or at the end of the catch block. However, a catch-all handler may call
|
|
// end catch from the original landing pad. If the call occurs in a nested
|
|
// landing pad block, we must skip it and continue so that the landing pad
|
|
// gets cloned.
|
|
auto *ParentBB = IntrinCall->getParent();
|
|
if (ParentBB->isLandingPad() && !LPadMap.isOriginLandingPadBlock(ParentBB))
|
|
return CloningDirector::SkipInstruction;
|
|
|
|
// If an end catch occurs anywhere else we want to terminate the handler
|
|
// with a return to the code that follows the endcatch call. If the
|
|
// next instruction is not an unconditional branch, we need to split the
|
|
// block to provide a clear target for the return instruction.
|
|
BasicBlock *ContinueBB;
|
|
auto Next = std::next(BasicBlock::const_iterator(IntrinCall));
|
|
const BranchInst *Branch = dyn_cast<BranchInst>(Next);
|
|
if (!Branch || !Branch->isUnconditional()) {
|
|
// We're interrupting the cloning process at this location, so the
|
|
// const_cast we're doing here will not cause a problem.
|
|
ContinueBB = SplitBlock(const_cast<BasicBlock *>(ParentBB),
|
|
const_cast<Instruction *>(cast<Instruction>(Next)));
|
|
} else {
|
|
ContinueBB = Branch->getSuccessor(0);
|
|
}
|
|
|
|
ReturnInst::Create(NewBB->getContext(), BlockAddress::get(ContinueBB), NewBB);
|
|
ReturnTargets.push_back(ContinueBB);
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block so that
|
|
// the branch instruction will be skipped.
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst);
|
|
Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts();
|
|
// This causes a replacement that will collapse the landing pad CFG based
|
|
// on the filter function we intend to match.
|
|
if (Selector == CurrentSelector)
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 1);
|
|
else
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
|
|
// Tell the caller not to clone this instruction.
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCatchDirector::handleInvoke(ValueToValueMapTy &VMap,
|
|
const InvokeInst *Invoke, BasicBlock *NewBB) {
|
|
return CloningDirector::CloneInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction
|
|
WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap,
|
|
const ResumeInst *Resume, BasicBlock *NewBB) {
|
|
// Resume instructions shouldn't be reachable from catch handlers.
|
|
// We still need to handle it, but it will be pruned.
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(new UnreachableInst(NewBB->getContext()));
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleLandingPad(
|
|
ValueToValueMapTy &VMap, const LandingPadInst *LPad, BasicBlock *NewBB) {
|
|
// The MS runtime will terminate the process if an exception occurs in a
|
|
// cleanup handler, so we shouldn't encounter landing pads in the actual
|
|
// cleanup code, but they may appear in catch blocks. Depending on where
|
|
// we started cloning we may see one, but it will get dropped during dead
|
|
// block pruning.
|
|
Instruction *NewInst = new UnreachableInst(NewBB->getContext());
|
|
VMap[LPad] = NewInst;
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(NewInst);
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// Catch blocks within cleanup handlers will always be unreachable.
|
|
// We'll insert an unreachable instruction now, but it will be pruned
|
|
// before the cloning process is complete.
|
|
BasicBlock::InstListType &InstList = NewBB->getInstList();
|
|
InstList.push_back(new UnreachableInst(NewBB->getContext()));
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// Cleanup handlers nested within catch handlers may begin with a call to
|
|
// eh.endcatch. We can just ignore that instruction.
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor(
|
|
ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) {
|
|
// If we encounter a selector comparison while cloning a cleanup handler,
|
|
// we want to stop cloning immediately. Anything after the dispatch
|
|
// will be outlined into a different handler.
|
|
BasicBlock *CatchHandler;
|
|
Constant *Selector;
|
|
BasicBlock *NextBB;
|
|
if (isSelectorDispatch(const_cast<BasicBlock *>(Inst->getParent()),
|
|
CatchHandler, Selector, NextBB)) {
|
|
ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
// If eg.typeid.for is called for any other reason, it can be ignored.
|
|
VMap[Inst] = ConstantInt::get(SelectorIDType, 0);
|
|
return CloningDirector::SkipInstruction;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleInvoke(
|
|
ValueToValueMapTy &VMap, const InvokeInst *Invoke, BasicBlock *NewBB) {
|
|
// All invokes in cleanup handlers can be replaced with calls.
|
|
SmallVector<Value *, 16> CallArgs(Invoke->op_begin(), Invoke->op_end() - 3);
|
|
// Insert a normal call instruction...
|
|
CallInst *NewCall =
|
|
CallInst::Create(const_cast<Value *>(Invoke->getCalledValue()), CallArgs,
|
|
Invoke->getName(), NewBB);
|
|
NewCall->setCallingConv(Invoke->getCallingConv());
|
|
NewCall->setAttributes(Invoke->getAttributes());
|
|
NewCall->setDebugLoc(Invoke->getDebugLoc());
|
|
VMap[Invoke] = NewCall;
|
|
|
|
// Remap the operands.
|
|
llvm::RemapInstruction(NewCall, VMap, RF_None, nullptr, &Materializer);
|
|
|
|
// Insert an unconditional branch to the normal destination.
|
|
BranchInst::Create(Invoke->getNormalDest(), NewBB);
|
|
|
|
// The unwind destination won't be cloned into the new function, so
|
|
// we don't need to clean up its phi nodes.
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block.
|
|
return CloningDirector::CloneSuccessors;
|
|
}
|
|
|
|
CloningDirector::CloningAction WinEHCleanupDirector::handleResume(
|
|
ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) {
|
|
ReturnInst::Create(NewBB->getContext(), nullptr, NewBB);
|
|
|
|
// We just added a terminator to the cloned block.
|
|
// Tell the caller to stop processing the current basic block so that
|
|
// the branch instruction will be skipped.
|
|
return CloningDirector::StopCloningBB;
|
|
}
|
|
|
|
WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer(
|
|
Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo)
|
|
: FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) {
|
|
BasicBlock *EntryBB = &OutlinedFn->getEntryBlock();
|
|
Builder.SetInsertPoint(EntryBB, EntryBB->getFirstInsertionPt());
|
|
}
|
|
|
|
Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) {
|
|
// If we're asked to materialize a value that is an instruction, we
|
|
// temporarily create an alloca in the outlined function and add this
|
|
// to the FrameVarInfo map. When all the outlining is complete, we'll
|
|
// collect these into a structure, spilling non-alloca values in the
|
|
// parent frame as necessary, and replace these temporary allocas with
|
|
// GEPs referencing the frame allocation block.
|
|
|
|
// If the value is an alloca, the mapping is direct.
|
|
if (auto *AV = dyn_cast<AllocaInst>(V)) {
|
|
AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone());
|
|
Builder.Insert(NewAlloca, AV->getName());
|
|
FrameVarInfo[AV].push_back(NewAlloca);
|
|
return NewAlloca;
|
|
}
|
|
|
|
// For other types of instructions or arguments, we need an alloca based on
|
|
// the value's type and a load of the alloca. The alloca will be replaced
|
|
// by a GEP, but the load will stay. In the parent function, the value will
|
|
// be spilled to a location in the frame allocation block.
|
|
if (isa<Instruction>(V) || isa<Argument>(V)) {
|
|
AllocaInst *NewAlloca =
|
|
Builder.CreateAlloca(V->getType(), nullptr, "eh.temp.alloca");
|
|
FrameVarInfo[V].push_back(NewAlloca);
|
|
LoadInst *NewLoad = Builder.CreateLoad(NewAlloca, V->getName() + ".reload");
|
|
return NewLoad;
|
|
}
|
|
|
|
// Don't materialize other values.
|
|
return nullptr;
|
|
}
|
|
|
|
void WinEHFrameVariableMaterializer::escapeCatchObject(Value *V) {
|
|
// Catch parameter objects have to live in the parent frame. When we see a use
|
|
// of a catch parameter, add a sentinel to the multimap to indicate that it's
|
|
// used from another handler. This will prevent us from trying to sink the
|
|
// alloca into the handler and ensure that the catch parameter is present in
|
|
// the call to llvm.frameescape.
|
|
FrameVarInfo[V].push_back(getCatchObjectSentinel());
|
|
}
|
|
|
|
// This function maps the catch and cleanup handlers that are reachable from the
|
|
// specified landing pad. The landing pad sequence will have this basic shape:
|
|
//
|
|
// <cleanup handler>
|
|
// <selector comparison>
|
|
// <catch handler>
|
|
// <cleanup handler>
|
|
// <selector comparison>
|
|
// <catch handler>
|
|
// <cleanup handler>
|
|
// ...
|
|
//
|
|
// Any of the cleanup slots may be absent. The cleanup slots may be occupied by
|
|
// any arbitrary control flow, but all paths through the cleanup code must
|
|
// eventually reach the next selector comparison and no path can skip to a
|
|
// different selector comparisons, though some paths may terminate abnormally.
|
|
// Therefore, we will use a depth first search from the start of any given
|
|
// cleanup block and stop searching when we find the next selector comparison.
|
|
//
|
|
// If the landingpad instruction does not have a catch clause, we will assume
|
|
// that any instructions other than selector comparisons and catch handlers can
|
|
// be ignored. In practice, these will only be the boilerplate instructions.
|
|
//
|
|
// The catch handlers may also have any control structure, but we are only
|
|
// interested in the start of the catch handlers, so we don't need to actually
|
|
// follow the flow of the catch handlers. The start of the catch handlers can
|
|
// be located from the compare instructions, but they can be skipped in the
|
|
// flow by following the contrary branch.
|
|
void WinEHPrepare::mapLandingPadBlocks(LandingPadInst *LPad,
|
|
LandingPadActions &Actions) {
|
|
unsigned int NumClauses = LPad->getNumClauses();
|
|
unsigned int HandlersFound = 0;
|
|
BasicBlock *BB = LPad->getParent();
|
|
|
|
DEBUG(dbgs() << "Mapping landing pad: " << BB->getName() << "\n");
|
|
|
|
if (NumClauses == 0) {
|
|
findCleanupHandlers(Actions, BB, nullptr);
|
|
return;
|
|
}
|
|
|
|
VisitedBlockSet VisitedBlocks;
|
|
|
|
while (HandlersFound != NumClauses) {
|
|
BasicBlock *NextBB = nullptr;
|
|
|
|
// See if the clause we're looking for is a catch-all.
|
|
// If so, the catch begins immediately.
|
|
if (isa<ConstantPointerNull>(LPad->getClause(HandlersFound))) {
|
|
// The catch all must occur last.
|
|
assert(HandlersFound == NumClauses - 1);
|
|
|
|
// For C++ EH, check if there is any interesting cleanup code before we
|
|
// begin the catch. This is important because cleanups cannot rethrow
|
|
// exceptions but code called from catches can. For SEH, it isn't
|
|
// important if some finally code before a catch-all is executed out of
|
|
// line or after recovering from the exception.
|
|
if (Personality == EHPersonality::MSVC_CXX)
|
|
findCleanupHandlers(Actions, BB, BB);
|
|
|
|
// Add the catch handler to the action list.
|
|
CatchHandler *Action =
|
|
new CatchHandler(BB, LPad->getClause(HandlersFound), nullptr);
|
|
CatchHandlerMap[BB] = Action;
|
|
Actions.insertCatchHandler(Action);
|
|
DEBUG(dbgs() << " Catch all handler at block " << BB->getName() << "\n");
|
|
++HandlersFound;
|
|
|
|
// Once we reach a catch-all, don't expect to hit a resume instruction.
|
|
BB = nullptr;
|
|
break;
|
|
}
|
|
|
|
CatchHandler *CatchAction = findCatchHandler(BB, NextBB, VisitedBlocks);
|
|
// See if there is any interesting code executed before the dispatch.
|
|
findCleanupHandlers(Actions, BB, CatchAction->getStartBlock());
|
|
|
|
assert(CatchAction);
|
|
++HandlersFound;
|
|
|
|
// Add the catch handler to the action list.
|
|
Actions.insertCatchHandler(CatchAction);
|
|
DEBUG(dbgs() << " Found catch dispatch in block "
|
|
<< CatchAction->getStartBlock()->getName() << "\n");
|
|
|
|
// Move on to the block after the catch handler.
|
|
BB = NextBB;
|
|
}
|
|
|
|
// If we didn't wind up in a catch-all, see if there is any interesting code
|
|
// executed before the resume.
|
|
findCleanupHandlers(Actions, BB, BB);
|
|
|
|
// It's possible that some optimization moved code into a landingpad that
|
|
// wasn't
|
|
// previously being used for cleanup. If that happens, we need to execute
|
|
// that
|
|
// extra code from a cleanup handler.
|
|
if (Actions.includesCleanup() && !LPad->isCleanup())
|
|
LPad->setCleanup(true);
|
|
}
|
|
|
|
// This function searches starting with the input block for the next
|
|
// block that terminates with a branch whose condition is based on a selector
|
|
// comparison. This may be the input block. See the mapLandingPadBlocks
|
|
// comments for a discussion of control flow assumptions.
|
|
//
|
|
CatchHandler *WinEHPrepare::findCatchHandler(BasicBlock *BB,
|
|
BasicBlock *&NextBB,
|
|
VisitedBlockSet &VisitedBlocks) {
|
|
// See if we've already found a catch handler use it.
|
|
// Call count() first to avoid creating a null entry for blocks
|
|
// we haven't seen before.
|
|
if (CatchHandlerMap.count(BB) && CatchHandlerMap[BB] != nullptr) {
|
|
CatchHandler *Action = cast<CatchHandler>(CatchHandlerMap[BB]);
|
|
NextBB = Action->getNextBB();
|
|
return Action;
|
|
}
|
|
|
|
// VisitedBlocks applies only to the current search. We still
|
|
// need to consider blocks that we've visited while mapping other
|
|
// landing pads.
|
|
VisitedBlocks.insert(BB);
|
|
|
|
BasicBlock *CatchBlock = nullptr;
|
|
Constant *Selector = nullptr;
|
|
|
|
// If this is the first time we've visited this block from any landing pad
|
|
// look to see if it is a selector dispatch block.
|
|
if (!CatchHandlerMap.count(BB)) {
|
|
if (isSelectorDispatch(BB, CatchBlock, Selector, NextBB)) {
|
|
CatchHandler *Action = new CatchHandler(BB, Selector, NextBB);
|
|
CatchHandlerMap[BB] = Action;
|
|
return Action;
|
|
}
|
|
}
|
|
|
|
// Visit each successor, looking for the dispatch.
|
|
// FIXME: We expect to find the dispatch quickly, so this will probably
|
|
// work better as a breadth first search.
|
|
for (BasicBlock *Succ : successors(BB)) {
|
|
if (VisitedBlocks.count(Succ))
|
|
continue;
|
|
|
|
CatchHandler *Action = findCatchHandler(Succ, NextBB, VisitedBlocks);
|
|
if (Action)
|
|
return Action;
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
// These are helper functions to combine repeated code from findCleanupHandlers.
|
|
static void createCleanupHandler(LandingPadActions &Actions,
|
|
CleanupHandlerMapTy &CleanupHandlerMap,
|
|
BasicBlock *BB) {
|
|
CleanupHandler *Action = new CleanupHandler(BB);
|
|
CleanupHandlerMap[BB] = Action;
|
|
Actions.insertCleanupHandler(Action);
|
|
DEBUG(dbgs() << " Found cleanup code in block "
|
|
<< Action->getStartBlock()->getName() << "\n");
|
|
}
|
|
|
|
static bool isFrameAddressCall(Value *V) {
|
|
return match(V, m_Intrinsic<Intrinsic::frameaddress>(m_SpecificInt(0)));
|
|
}
|
|
|
|
static CallSite matchOutlinedFinallyCall(BasicBlock *BB,
|
|
Instruction *MaybeCall) {
|
|
// Look for finally blocks that Clang has already outlined for us.
|
|
// %fp = call i8* @llvm.frameaddress(i32 0)
|
|
// call void @"fin$parent"(iN 1, i8* %fp)
|
|
if (isFrameAddressCall(MaybeCall) && MaybeCall != BB->getTerminator())
|
|
MaybeCall = MaybeCall->getNextNode();
|
|
CallSite FinallyCall(MaybeCall);
|
|
if (!FinallyCall || FinallyCall.arg_size() != 2)
|
|
return CallSite();
|
|
if (!match(FinallyCall.getArgument(0), m_SpecificInt(1)))
|
|
return CallSite();
|
|
if (!isFrameAddressCall(FinallyCall.getArgument(1)))
|
|
return CallSite();
|
|
return FinallyCall;
|
|
}
|
|
|
|
static BasicBlock *followSingleUnconditionalBranches(BasicBlock *BB) {
|
|
// Skip single ubr blocks.
|
|
while (BB->getFirstNonPHIOrDbg() == BB->getTerminator()) {
|
|
auto *Br = dyn_cast<BranchInst>(BB->getTerminator());
|
|
if (Br && Br->isUnconditional())
|
|
BB = Br->getSuccessor(0);
|
|
else
|
|
return BB;
|
|
}
|
|
return BB;
|
|
}
|
|
|
|
// This function searches starting with the input block for the next block that
|
|
// contains code that is not part of a catch handler and would not be eliminated
|
|
// during handler outlining.
|
|
//
|
|
void WinEHPrepare::findCleanupHandlers(LandingPadActions &Actions,
|
|
BasicBlock *StartBB, BasicBlock *EndBB) {
|
|
// Here we will skip over the following:
|
|
//
|
|
// landing pad prolog:
|
|
//
|
|
// Unconditional branches
|
|
//
|
|
// Selector dispatch
|
|
//
|
|
// Resume pattern
|
|
//
|
|
// Anything else marks the start of an interesting block
|
|
|
|
BasicBlock *BB = StartBB;
|
|
// Anything other than an unconditional branch will kick us out of this loop
|
|
// one way or another.
|
|
while (BB) {
|
|
BB = followSingleUnconditionalBranches(BB);
|
|
// If we've already scanned this block, don't scan it again. If it is
|
|
// a cleanup block, there will be an action in the CleanupHandlerMap.
|
|
// If we've scanned it and it is not a cleanup block, there will be a
|
|
// nullptr in the CleanupHandlerMap. If we have not scanned it, there will
|
|
// be no entry in the CleanupHandlerMap. We must call count() first to
|
|
// avoid creating a null entry for blocks we haven't scanned.
|
|
if (CleanupHandlerMap.count(BB)) {
|
|
if (auto *Action = CleanupHandlerMap[BB]) {
|
|
Actions.insertCleanupHandler(Action);
|
|
DEBUG(dbgs() << " Found cleanup code in block "
|
|
<< Action->getStartBlock()->getName() << "\n");
|
|
// FIXME: This cleanup might chain into another, and we need to discover
|
|
// that.
|
|
return;
|
|
} else {
|
|
// Here we handle the case where the cleanup handler map contains a
|
|
// value for this block but the value is a nullptr. This means that
|
|
// we have previously analyzed the block and determined that it did
|
|
// not contain any cleanup code. Based on the earlier analysis, we
|
|
// know the the block must end in either an unconditional branch, a
|
|
// resume or a conditional branch that is predicated on a comparison
|
|
// with a selector. Either the resume or the selector dispatch
|
|
// would terminate the search for cleanup code, so the unconditional
|
|
// branch is the only case for which we might need to continue
|
|
// searching.
|
|
BasicBlock *SuccBB = followSingleUnconditionalBranches(BB);
|
|
if (SuccBB == BB || SuccBB == EndBB)
|
|
return;
|
|
BB = SuccBB;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Create an entry in the cleanup handler map for this block. Initially
|
|
// we create an entry that says this isn't a cleanup block. If we find
|
|
// cleanup code, the caller will replace this entry.
|
|
CleanupHandlerMap[BB] = nullptr;
|
|
|
|
TerminatorInst *Terminator = BB->getTerminator();
|
|
|
|
// Landing pad blocks have extra instructions we need to accept.
|
|
LandingPadMap *LPadMap = nullptr;
|
|
if (BB->isLandingPad()) {
|
|
LandingPadInst *LPad = BB->getLandingPadInst();
|
|
LPadMap = &LPadMaps[LPad];
|
|
if (!LPadMap->isInitialized())
|
|
LPadMap->mapLandingPad(LPad);
|
|
}
|
|
|
|
// Look for the bare resume pattern:
|
|
// %lpad.val1 = insertvalue { i8*, i32 } undef, i8* %exn, 0
|
|
// %lpad.val2 = insertvalue { i8*, i32 } %lpad.val1, i32 %sel, 1
|
|
// resume { i8*, i32 } %lpad.val2
|
|
if (auto *Resume = dyn_cast<ResumeInst>(Terminator)) {
|
|
InsertValueInst *Insert1 = nullptr;
|
|
InsertValueInst *Insert2 = nullptr;
|
|
Value *ResumeVal = Resume->getOperand(0);
|
|
// If there is only one landingpad, we may use the lpad directly with no
|
|
// insertions.
|
|
if (isa<LandingPadInst>(ResumeVal))
|
|
return;
|
|
if (!isa<PHINode>(ResumeVal)) {
|
|
Insert2 = dyn_cast<InsertValueInst>(ResumeVal);
|
|
if (!Insert2)
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
Insert1 = dyn_cast<InsertValueInst>(Insert2->getAggregateOperand());
|
|
if (!Insert1)
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
}
|
|
for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
|
|
II != IE; ++II) {
|
|
Instruction *Inst = II;
|
|
if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
|
|
continue;
|
|
if (Inst == Insert1 || Inst == Insert2 || Inst == Resume)
|
|
continue;
|
|
if (!Inst->hasOneUse() ||
|
|
(Inst->user_back() != Insert1 && Inst->user_back() != Insert2)) {
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
|
|
BranchInst *Branch = dyn_cast<BranchInst>(Terminator);
|
|
if (Branch && Branch->isConditional()) {
|
|
// Look for the selector dispatch.
|
|
// %2 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIf to i8*))
|
|
// %matches = icmp eq i32 %sel, %2
|
|
// br i1 %matches, label %catch14, label %eh.resume
|
|
CmpInst *Compare = dyn_cast<CmpInst>(Branch->getCondition());
|
|
if (!Compare || !Compare->isEquality())
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
|
|
II != IE; ++II) {
|
|
Instruction *Inst = II;
|
|
if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
|
|
continue;
|
|
if (Inst == Compare || Inst == Branch)
|
|
continue;
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>()))
|
|
continue;
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
}
|
|
// The selector dispatch block should always terminate our search.
|
|
assert(BB == EndBB);
|
|
return;
|
|
}
|
|
|
|
if (isAsynchronousEHPersonality(Personality)) {
|
|
// If this is a landingpad block, split the block at the first non-landing
|
|
// pad instruction.
|
|
Instruction *MaybeCall = BB->getFirstNonPHIOrDbg();
|
|
if (LPadMap) {
|
|
while (MaybeCall != BB->getTerminator() &&
|
|
LPadMap->isLandingPadSpecificInst(MaybeCall))
|
|
MaybeCall = MaybeCall->getNextNode();
|
|
}
|
|
|
|
// Look for outlined finally calls.
|
|
if (CallSite FinallyCall = matchOutlinedFinallyCall(BB, MaybeCall)) {
|
|
Function *Fin = FinallyCall.getCalledFunction();
|
|
assert(Fin && "outlined finally call should be direct");
|
|
auto *Action = new CleanupHandler(BB);
|
|
Action->setHandlerBlockOrFunc(Fin);
|
|
Actions.insertCleanupHandler(Action);
|
|
CleanupHandlerMap[BB] = Action;
|
|
DEBUG(dbgs() << " Found frontend-outlined finally call to "
|
|
<< Fin->getName() << " in block "
|
|
<< Action->getStartBlock()->getName() << "\n");
|
|
|
|
// Split the block if there were more interesting instructions and look
|
|
// for finally calls in the normal successor block.
|
|
BasicBlock *SuccBB = BB;
|
|
if (FinallyCall.getInstruction() != BB->getTerminator() &&
|
|
FinallyCall.getInstruction()->getNextNode() != BB->getTerminator()) {
|
|
SuccBB = BB->splitBasicBlock(FinallyCall.getInstruction()->getNextNode());
|
|
} else {
|
|
if (FinallyCall.isInvoke()) {
|
|
SuccBB = cast<InvokeInst>(FinallyCall.getInstruction())->getNormalDest();
|
|
} else {
|
|
SuccBB = BB->getUniqueSuccessor();
|
|
assert(SuccBB && "splitOutlinedFinallyCalls didn't insert a branch");
|
|
}
|
|
}
|
|
BB = SuccBB;
|
|
if (BB == EndBB)
|
|
return;
|
|
continue;
|
|
}
|
|
}
|
|
|
|
// Anything else is either a catch block or interesting cleanup code.
|
|
for (BasicBlock::iterator II = BB->getFirstNonPHIOrDbg(), IE = BB->end();
|
|
II != IE; ++II) {
|
|
Instruction *Inst = II;
|
|
if (LPadMap && LPadMap->isLandingPadSpecificInst(Inst))
|
|
continue;
|
|
// Unconditional branches fall through to this loop.
|
|
if (Inst == Branch)
|
|
continue;
|
|
// If this is a catch block, there is no cleanup code to be found.
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>()))
|
|
return;
|
|
// If this a nested landing pad, it may contain an endcatch call.
|
|
if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>()))
|
|
return;
|
|
// Anything else makes this interesting cleanup code.
|
|
return createCleanupHandler(Actions, CleanupHandlerMap, BB);
|
|
}
|
|
|
|
// Only unconditional branches in empty blocks should get this far.
|
|
assert(Branch && Branch->isUnconditional());
|
|
if (BB == EndBB)
|
|
return;
|
|
BB = Branch->getSuccessor(0);
|
|
}
|
|
return;
|
|
}
|
|
|
|
// This is a public function, declared in WinEHFuncInfo.h and is also
|
|
// referenced by WinEHNumbering in FunctionLoweringInfo.cpp.
|
|
void llvm::parseEHActions(const IntrinsicInst *II,
|
|
SmallVectorImpl<ActionHandler *> &Actions) {
|
|
for (unsigned I = 0, E = II->getNumArgOperands(); I != E;) {
|
|
uint64_t ActionKind =
|
|
cast<ConstantInt>(II->getArgOperand(I))->getZExtValue();
|
|
if (ActionKind == /*catch=*/1) {
|
|
auto *Selector = cast<Constant>(II->getArgOperand(I + 1));
|
|
ConstantInt *EHObjIndex = cast<ConstantInt>(II->getArgOperand(I + 2));
|
|
int64_t EHObjIndexVal = EHObjIndex->getSExtValue();
|
|
Constant *Handler = cast<Constant>(II->getArgOperand(I + 3));
|
|
I += 4;
|
|
auto *CH = new CatchHandler(/*BB=*/nullptr, Selector, /*NextBB=*/nullptr);
|
|
CH->setHandlerBlockOrFunc(Handler);
|
|
CH->setExceptionVarIndex(EHObjIndexVal);
|
|
Actions.push_back(CH);
|
|
} else if (ActionKind == 0) {
|
|
Constant *Handler = cast<Constant>(II->getArgOperand(I + 1));
|
|
I += 2;
|
|
auto *CH = new CleanupHandler(/*BB=*/nullptr);
|
|
CH->setHandlerBlockOrFunc(Handler);
|
|
Actions.push_back(CH);
|
|
} else {
|
|
llvm_unreachable("Expected either a catch or cleanup handler!");
|
|
}
|
|
}
|
|
std::reverse(Actions.begin(), Actions.end());
|
|
}
|