Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 1 | //===-- WinEHPrepare - Prepare exception handling for code generation ---===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This pass lowers LLVM IR exception handling into something closer to what the |
| 11 | // backend wants. It snifs the personality function to see which kind of |
| 12 | // preparation is necessary. If the personality function uses the Itanium LSDA, |
| 13 | // this pass delegates to the DWARF EH preparation pass. |
| 14 | // |
| 15 | //===----------------------------------------------------------------------===// |
| 16 | |
| 17 | #include "llvm/CodeGen/Passes.h" |
| 18 | #include "llvm/ADT/MapVector.h" |
| 19 | #include "llvm/ADT/TinyPtrVector.h" |
| 20 | #include "llvm/Analysis/LibCallSemantics.h" |
| 21 | #include "llvm/IR/Function.h" |
| 22 | #include "llvm/IR/IRBuilder.h" |
| 23 | #include "llvm/IR/Instructions.h" |
| 24 | #include "llvm/IR/IntrinsicInst.h" |
| 25 | #include "llvm/IR/Module.h" |
| 26 | #include "llvm/IR/PatternMatch.h" |
| 27 | #include "llvm/Pass.h" |
| 28 | #include "llvm/Transforms/Utils/Cloning.h" |
| 29 | #include "llvm/Transforms/Utils/Local.h" |
| 30 | #include <memory> |
| 31 | |
| 32 | using namespace llvm; |
| 33 | using namespace llvm::PatternMatch; |
| 34 | |
| 35 | #define DEBUG_TYPE "winehprepare" |
| 36 | |
| 37 | namespace { |
| 38 | |
| 39 | struct HandlerAllocas { |
| 40 | TinyPtrVector<AllocaInst *> Allocas; |
| 41 | int ParentFrameAllocationIndex; |
| 42 | }; |
| 43 | |
| 44 | // This map is used to model frame variable usage during outlining, to |
| 45 | // construct a structure type to hold the frame variables in a frame |
| 46 | // allocation block, and to remap the frame variable allocas (including |
| 47 | // spill locations as needed) to GEPs that get the variable from the |
| 48 | // frame allocation structure. |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 49 | typedef MapVector<Value *, HandlerAllocas> FrameVarInfoMap; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 50 | |
| 51 | class WinEHPrepare : public FunctionPass { |
| 52 | std::unique_ptr<FunctionPass> DwarfPrepare; |
| 53 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 54 | enum HandlerType { Catch, Cleanup }; |
| 55 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 56 | public: |
| 57 | static char ID; // Pass identification, replacement for typeid. |
| 58 | WinEHPrepare(const TargetMachine *TM = nullptr) |
| 59 | : FunctionPass(ID), DwarfPrepare(createDwarfEHPass(TM)) {} |
| 60 | |
| 61 | bool runOnFunction(Function &Fn) override; |
| 62 | |
| 63 | bool doFinalization(Module &M) override; |
| 64 | |
| 65 | void getAnalysisUsage(AnalysisUsage &AU) const override; |
| 66 | |
| 67 | const char *getPassName() const override { |
| 68 | return "Windows exception handling preparation"; |
| 69 | } |
| 70 | |
| 71 | private: |
| 72 | bool prepareCPPEHHandlers(Function &F, |
| 73 | SmallVectorImpl<LandingPadInst *> &LPads); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 74 | bool outlineHandler(HandlerType CatchOrCleanup, Function *SrcFn, |
| 75 | Constant *SelectorType, LandingPadInst *LPad, |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 76 | CallInst *&EHAlloc, FrameVarInfoMap &VarInfo); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 77 | }; |
| 78 | |
| 79 | class WinEHFrameVariableMaterializer : public ValueMaterializer { |
| 80 | public: |
| 81 | WinEHFrameVariableMaterializer(Function *OutlinedFn, |
| 82 | FrameVarInfoMap &FrameVarInfo); |
| 83 | ~WinEHFrameVariableMaterializer() {} |
| 84 | |
| 85 | virtual Value *materializeValueFor(Value *V) override; |
| 86 | |
| 87 | private: |
| 88 | FrameVarInfoMap &FrameVarInfo; |
| 89 | IRBuilder<> Builder; |
| 90 | }; |
| 91 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 92 | class WinEHCloningDirectorBase : public CloningDirector { |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 93 | public: |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 94 | WinEHCloningDirectorBase(LandingPadInst *LPI, Function *HandlerFn, |
| 95 | FrameVarInfoMap &VarInfo) |
| 96 | : LPI(LPI), Materializer(HandlerFn, VarInfo), |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 97 | SelectorIDType(Type::getInt32Ty(LPI->getContext())), |
| 98 | Int8PtrType(Type::getInt8PtrTy(LPI->getContext())) {} |
| 99 | |
| 100 | CloningAction handleInstruction(ValueToValueMapTy &VMap, |
| 101 | const Instruction *Inst, |
| 102 | BasicBlock *NewBB) override; |
| 103 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 104 | virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 105 | const Instruction *Inst, |
| 106 | BasicBlock *NewBB) = 0; |
| 107 | virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap, |
| 108 | const Instruction *Inst, |
| 109 | BasicBlock *NewBB) = 0; |
| 110 | virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 111 | const Instruction *Inst, |
| 112 | BasicBlock *NewBB) = 0; |
| 113 | virtual CloningAction handleResume(ValueToValueMapTy &VMap, |
| 114 | const ResumeInst *Resume, |
| 115 | BasicBlock *NewBB) = 0; |
| 116 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 117 | ValueMaterializer *getValueMaterializer() override { return &Materializer; } |
| 118 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 119 | protected: |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 120 | LandingPadInst *LPI; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 121 | WinEHFrameVariableMaterializer Materializer; |
| 122 | Type *SelectorIDType; |
| 123 | Type *Int8PtrType; |
| 124 | |
| 125 | const Value *ExtractedEHPtr; |
| 126 | const Value *ExtractedSelector; |
| 127 | const Value *EHPtrStoreAddr; |
| 128 | const Value *SelectorStoreAddr; |
| 129 | }; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 130 | |
| 131 | class WinEHCatchDirector : public WinEHCloningDirectorBase { |
| 132 | public: |
| 133 | WinEHCatchDirector(LandingPadInst *LPI, Function *CatchFn, Value *Selector, |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 134 | FrameVarInfoMap &VarInfo) |
Andrew Kaylor | e07b2a0 | 2015-03-03 20:22:09 +0000 | [diff] [blame] | 135 | : WinEHCloningDirectorBase(LPI, CatchFn, VarInfo), |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 136 | CurrentSelector(Selector->stripPointerCasts()) {} |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 137 | |
| 138 | CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 139 | const Instruction *Inst, |
| 140 | BasicBlock *NewBB) override; |
| 141 | CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| 142 | BasicBlock *NewBB) override; |
| 143 | CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 144 | const Instruction *Inst, |
| 145 | BasicBlock *NewBB) override; |
| 146 | CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| 147 | BasicBlock *NewBB) override; |
| 148 | |
| 149 | private: |
| 150 | Value *CurrentSelector; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 151 | }; |
| 152 | |
| 153 | class WinEHCleanupDirector : public WinEHCloningDirectorBase { |
| 154 | public: |
| 155 | WinEHCleanupDirector(LandingPadInst *LPI, Function *CleanupFn, |
| 156 | FrameVarInfoMap &VarInfo) |
| 157 | : WinEHCloningDirectorBase(LPI, CleanupFn, VarInfo) {} |
| 158 | |
| 159 | CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 160 | const Instruction *Inst, |
| 161 | BasicBlock *NewBB) override; |
| 162 | CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| 163 | BasicBlock *NewBB) override; |
| 164 | CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 165 | const Instruction *Inst, |
| 166 | BasicBlock *NewBB) override; |
| 167 | CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| 168 | BasicBlock *NewBB) override; |
| 169 | }; |
| 170 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 171 | } // end anonymous namespace |
| 172 | |
| 173 | char WinEHPrepare::ID = 0; |
| 174 | INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions", |
| 175 | false, false) |
| 176 | |
| 177 | FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) { |
| 178 | return new WinEHPrepare(TM); |
| 179 | } |
| 180 | |
| 181 | static bool isMSVCPersonality(EHPersonality Pers) { |
| 182 | return Pers == EHPersonality::MSVC_Win64SEH || |
| 183 | Pers == EHPersonality::MSVC_CXX; |
| 184 | } |
| 185 | |
| 186 | bool WinEHPrepare::runOnFunction(Function &Fn) { |
| 187 | SmallVector<LandingPadInst *, 4> LPads; |
| 188 | SmallVector<ResumeInst *, 4> Resumes; |
| 189 | for (BasicBlock &BB : Fn) { |
| 190 | if (auto *LP = BB.getLandingPadInst()) |
| 191 | LPads.push_back(LP); |
| 192 | if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator())) |
| 193 | Resumes.push_back(Resume); |
| 194 | } |
| 195 | |
| 196 | // No need to prepare functions that lack landing pads. |
| 197 | if (LPads.empty()) |
| 198 | return false; |
| 199 | |
| 200 | // Classify the personality to see what kind of preparation we need. |
| 201 | EHPersonality Pers = classifyEHPersonality(LPads.back()->getPersonalityFn()); |
| 202 | |
| 203 | // Delegate through to the DWARF pass if this is unrecognized. |
| 204 | if (!isMSVCPersonality(Pers)) |
| 205 | return DwarfPrepare->runOnFunction(Fn); |
| 206 | |
| 207 | // FIXME: This only returns true if the C++ EH handlers were outlined. |
| 208 | // When that code is complete, it should always return whatever |
| 209 | // prepareCPPEHHandlers returns. |
| 210 | if (Pers == EHPersonality::MSVC_CXX && prepareCPPEHHandlers(Fn, LPads)) |
| 211 | return true; |
| 212 | |
| 213 | // FIXME: SEH Cleanups are unimplemented. Replace them with unreachable. |
| 214 | if (Resumes.empty()) |
| 215 | return false; |
| 216 | |
| 217 | for (ResumeInst *Resume : Resumes) { |
| 218 | IRBuilder<>(Resume).CreateUnreachable(); |
| 219 | Resume->eraseFromParent(); |
| 220 | } |
| 221 | |
| 222 | return true; |
| 223 | } |
| 224 | |
| 225 | bool WinEHPrepare::doFinalization(Module &M) { |
| 226 | return DwarfPrepare->doFinalization(M); |
| 227 | } |
| 228 | |
| 229 | void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const { |
| 230 | DwarfPrepare->getAnalysisUsage(AU); |
| 231 | } |
| 232 | |
| 233 | bool WinEHPrepare::prepareCPPEHHandlers( |
| 234 | Function &F, SmallVectorImpl<LandingPadInst *> &LPads) { |
| 235 | // These containers are used to re-map frame variables that are used in |
| 236 | // outlined catch and cleanup handlers. They will be populated as the |
| 237 | // handlers are outlined. |
| 238 | FrameVarInfoMap FrameVarInfo; |
| 239 | SmallVector<CallInst *, 4> HandlerAllocs; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 240 | |
| 241 | bool HandlersOutlined = false; |
| 242 | |
| 243 | for (LandingPadInst *LPad : LPads) { |
| 244 | // Look for evidence that this landingpad has already been processed. |
| 245 | bool LPadHasActionList = false; |
| 246 | BasicBlock *LPadBB = LPad->getParent(); |
| 247 | for (Instruction &Inst : LPadBB->getInstList()) { |
| 248 | // FIXME: Make this an intrinsic. |
| 249 | if (auto *Call = dyn_cast<CallInst>(&Inst)) |
| 250 | if (Call->getCalledFunction()->getName() == "llvm.eh.actions") { |
| 251 | LPadHasActionList = true; |
| 252 | break; |
| 253 | } |
| 254 | } |
| 255 | |
| 256 | // If we've already outlined the handlers for this landingpad, |
| 257 | // there's nothing more to do here. |
| 258 | if (LPadHasActionList) |
| 259 | continue; |
| 260 | |
| 261 | for (unsigned Idx = 0, NumClauses = LPad->getNumClauses(); Idx < NumClauses; |
| 262 | ++Idx) { |
| 263 | if (LPad->isCatch(Idx)) { |
| 264 | // Create a new instance of the handler data structure in the |
| 265 | // HandlerData vector. |
| 266 | CallInst *EHAlloc = nullptr; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 267 | bool Outlined = outlineHandler(Catch, &F, LPad->getClause(Idx), LPad, |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 268 | EHAlloc, FrameVarInfo); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 269 | if (Outlined) { |
| 270 | HandlersOutlined = true; |
| 271 | // These values must be resolved after all handlers have been |
| 272 | // outlined. |
| 273 | if (EHAlloc) |
| 274 | HandlerAllocs.push_back(EHAlloc); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 275 | } |
| 276 | } // End if (isCatch) |
| 277 | } // End for each clause |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 278 | |
| 279 | // FIXME: This only handles the simple case where there is a 1:1 |
| 280 | // correspondence between landing pad and cleanup blocks. |
| 281 | // It does not handle cases where there are catch blocks between |
| 282 | // cleanup blocks or the case where a cleanup block is shared by |
| 283 | // multiple landing pads. Those cases will be supported later |
| 284 | // when landing pad block analysis is added. |
| 285 | if (LPad->isCleanup()) { |
| 286 | CallInst *EHAlloc = nullptr; |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 287 | bool Outlined = |
| 288 | outlineHandler(Cleanup, &F, nullptr, LPad, EHAlloc, FrameVarInfo); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 289 | if (Outlined) { |
| 290 | HandlersOutlined = true; |
| 291 | // This value must be resolved after all handlers have been outlined. |
| 292 | if (EHAlloc) |
| 293 | HandlerAllocs.push_back(EHAlloc); |
| 294 | } |
| 295 | } |
| 296 | } // End for each landingpad |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 297 | |
| 298 | // If nothing got outlined, there is no more processing to be done. |
| 299 | if (!HandlersOutlined) |
| 300 | return false; |
| 301 | |
| 302 | // FIXME: We will replace the landingpad bodies with llvm.eh.actions |
| 303 | // calls and indirect branches here and then delete blocks |
| 304 | // which are no longer reachable. That will get rid of the |
| 305 | // handlers that we have outlined. There is code below |
| 306 | // that looks for allocas with no uses in the parent function. |
| 307 | // That will only happen after the pruning is implemented. |
| 308 | |
| 309 | // Remap the frame variables. |
| 310 | SmallVector<Type *, 2> StructTys; |
| 311 | StructTys.push_back(Type::getInt32Ty(F.getContext())); // EH state |
| 312 | StructTys.push_back(Type::getInt8PtrTy(F.getContext())); // EH object |
| 313 | |
| 314 | // Start the index at two since we always have the above fields at 0 and 1. |
| 315 | int Idx = 2; |
| 316 | |
| 317 | // FIXME: Sort the FrameVarInfo vector by the ParentAlloca size and alignment |
| 318 | // and add padding as necessary to provide the proper alignment. |
| 319 | |
| 320 | // Map the alloca instructions to the corresponding index in the |
| 321 | // frame allocation structure. If any alloca is used only in a single |
| 322 | // handler and is not used in the parent frame after outlining, it will |
| 323 | // be assigned an index of -1, meaning the handler can keep its |
| 324 | // "temporary" alloca and the original alloca can be erased from the |
| 325 | // parent function. If we later encounter this alloca in a second |
| 326 | // handler, we will assign it a place in the frame allocation structure |
| 327 | // at that time. Since the instruction replacement doesn't happen until |
| 328 | // all the entries in the HandlerData have been processed this isn't a |
| 329 | // problem. |
| 330 | for (auto &VarInfoEntry : FrameVarInfo) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 331 | Value *ParentVal = VarInfoEntry.first; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 332 | HandlerAllocas &AllocaInfo = VarInfoEntry.second; |
| 333 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 334 | if (auto *ParentAlloca = dyn_cast<AllocaInst>(ParentVal)) { |
| 335 | // If the instruction still has uses in the parent function or if it is |
| 336 | // referenced by more than one handler, add it to the frame allocation |
| 337 | // structure. |
| 338 | if (ParentAlloca->getNumUses() != 0 || AllocaInfo.Allocas.size() > 1) { |
| 339 | Type *VarTy = ParentAlloca->getAllocatedType(); |
| 340 | StructTys.push_back(VarTy); |
| 341 | AllocaInfo.ParentFrameAllocationIndex = Idx++; |
| 342 | } else { |
| 343 | // If the variable is not used in the parent frame and it is only used |
| 344 | // in one handler, the alloca can be removed from the parent frame |
| 345 | // and the handler will keep its "temporary" alloca to define the value. |
| 346 | // An element index of -1 is used to indicate this condition. |
| 347 | AllocaInfo.ParentFrameAllocationIndex = -1; |
| 348 | } |
| 349 | } else { |
| 350 | // FIXME: Sink non-alloca values into the handler if they have no other |
| 351 | // uses in the parent function after outlining and are only used in |
| 352 | // one handler. |
| 353 | Type *VarTy = ParentVal->getType(); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 354 | StructTys.push_back(VarTy); |
| 355 | AllocaInfo.ParentFrameAllocationIndex = Idx++; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 356 | } |
| 357 | } |
| 358 | |
| 359 | // Having filled the StructTys vector and assigned an index to each element, |
| 360 | // we can now create the structure. |
| 361 | StructType *EHDataStructTy = StructType::create( |
| 362 | F.getContext(), StructTys, "struct." + F.getName().str() + ".ehdata"); |
| 363 | IRBuilder<> Builder(F.getParent()->getContext()); |
| 364 | |
| 365 | // Create a frame allocation. |
| 366 | Module *M = F.getParent(); |
| 367 | LLVMContext &Context = M->getContext(); |
| 368 | BasicBlock *Entry = &F.getEntryBlock(); |
| 369 | Builder.SetInsertPoint(Entry->getFirstInsertionPt()); |
| 370 | Function *FrameAllocFn = |
| 371 | Intrinsic::getDeclaration(M, Intrinsic::frameallocate); |
| 372 | uint64_t EHAllocSize = M->getDataLayout()->getTypeAllocSize(EHDataStructTy); |
| 373 | Value *FrameAllocArgs[] = { |
| 374 | ConstantInt::get(Type::getInt32Ty(Context), EHAllocSize)}; |
| 375 | CallInst *FrameAlloc = |
| 376 | Builder.CreateCall(FrameAllocFn, FrameAllocArgs, "frame.alloc"); |
| 377 | |
| 378 | Value *FrameEHData = Builder.CreateBitCast( |
| 379 | FrameAlloc, EHDataStructTy->getPointerTo(), "eh.data"); |
| 380 | |
| 381 | // Now visit each handler that is using the structure and bitcast its EHAlloc |
| 382 | // value to be a pointer to the frame alloc structure. |
| 383 | DenseMap<Function *, Value *> EHDataMap; |
| 384 | for (CallInst *EHAlloc : HandlerAllocs) { |
| 385 | // The EHAlloc has no uses at this time, so we need to just insert the |
| 386 | // cast before the next instruction. There is always a next instruction. |
| 387 | BasicBlock::iterator II = EHAlloc; |
| 388 | ++II; |
| 389 | Builder.SetInsertPoint(cast<Instruction>(II)); |
| 390 | Value *EHData = Builder.CreateBitCast( |
| 391 | EHAlloc, EHDataStructTy->getPointerTo(), "eh.data"); |
| 392 | EHDataMap[EHAlloc->getParent()->getParent()] = EHData; |
| 393 | } |
| 394 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 395 | // Finally, replace all of the temporary allocas for frame variables used in |
| 396 | // the outlined handlers and the original frame allocas with GEP instructions |
| 397 | // that get the equivalent pointer from the frame allocation struct. |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 398 | Instruction *FrameEHDataInst = cast<Instruction>(FrameEHData); |
| 399 | BasicBlock::iterator II = FrameEHDataInst; |
| 400 | ++II; |
| 401 | Instruction *AllocaInsertPt = II; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 402 | for (auto &VarInfoEntry : FrameVarInfo) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 403 | Value *ParentVal = VarInfoEntry.first; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 404 | HandlerAllocas &AllocaInfo = VarInfoEntry.second; |
| 405 | int Idx = AllocaInfo.ParentFrameAllocationIndex; |
| 406 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 407 | // If the mapped value isn't already an alloca, we need to spill it if it |
| 408 | // is a computed value or copy it if it is an argument. |
| 409 | AllocaInst *ParentAlloca = dyn_cast<AllocaInst>(ParentVal); |
| 410 | if (!ParentAlloca) { |
| 411 | if (auto *Arg = dyn_cast<Argument>(ParentVal)) { |
| 412 | // Lower this argument to a copy and then demote that to the stack. |
| 413 | // We can't just use the argument location because the handler needs |
| 414 | // it to be in the frame allocation block. |
| 415 | // Use 'select i8 true, %arg, undef' to simulate a 'no-op' instruction. |
| 416 | Value *TrueValue = ConstantInt::getTrue(Context); |
| 417 | Value *UndefValue = UndefValue::get(Arg->getType()); |
| 418 | Instruction *SI = |
| 419 | SelectInst::Create(TrueValue, Arg, UndefValue, |
| 420 | Arg->getName() + ".tmp", AllocaInsertPt); |
| 421 | Arg->replaceAllUsesWith(SI); |
| 422 | // Reset the select operand, because it was clobbered by the RAUW above. |
| 423 | SI->setOperand(1, Arg); |
| 424 | ParentAlloca = DemoteRegToStack(*SI, true, SI); |
| 425 | } else if (auto *PN = dyn_cast<PHINode>(ParentVal)) { |
| 426 | ParentAlloca = DemotePHIToStack(PN, AllocaInsertPt); |
| 427 | } else { |
| 428 | Instruction *ParentInst = cast<Instruction>(ParentVal); |
| 429 | ParentAlloca = DemoteRegToStack(*ParentInst, true, ParentInst); |
| 430 | } |
| 431 | } |
| 432 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 433 | // If we have an index of -1 for this instruction, it means it isn't used |
| 434 | // outside of this handler. In that case, we just keep the "temporary" |
| 435 | // alloca in the handler and erase the original alloca from the parent. |
| 436 | if (Idx == -1) { |
| 437 | ParentAlloca->eraseFromParent(); |
| 438 | } else { |
| 439 | // Otherwise, we replace the parent alloca and all outlined allocas |
| 440 | // which map to it with GEP instructions. |
| 441 | |
| 442 | // First replace the original alloca. |
| 443 | Builder.SetInsertPoint(ParentAlloca); |
| 444 | Builder.SetCurrentDebugLocation(ParentAlloca->getDebugLoc()); |
| 445 | Value *ElementPtr = |
| 446 | Builder.CreateConstInBoundsGEP2_32(FrameEHData, 0, Idx); |
| 447 | ParentAlloca->replaceAllUsesWith(ElementPtr); |
| 448 | ParentAlloca->removeFromParent(); |
| 449 | ElementPtr->takeName(ParentAlloca); |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 450 | if (ParentAlloca == AllocaInsertPt) |
| 451 | AllocaInsertPt = dyn_cast<Instruction>(ElementPtr); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 452 | delete ParentAlloca; |
| 453 | |
| 454 | // Next replace all outlined allocas that are mapped to it. |
| 455 | for (AllocaInst *TempAlloca : AllocaInfo.Allocas) { |
| 456 | Value *EHData = EHDataMap[TempAlloca->getParent()->getParent()]; |
| 457 | // FIXME: Sink this GEP into the blocks where it is used. |
| 458 | Builder.SetInsertPoint(TempAlloca); |
| 459 | Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc()); |
| 460 | ElementPtr = Builder.CreateConstInBoundsGEP2_32(EHData, 0, Idx); |
| 461 | TempAlloca->replaceAllUsesWith(ElementPtr); |
| 462 | TempAlloca->removeFromParent(); |
| 463 | ElementPtr->takeName(TempAlloca); |
| 464 | delete TempAlloca; |
| 465 | } |
| 466 | } // end else of if (Idx == -1) |
| 467 | } // End for each FrameVarInfo entry. |
| 468 | |
| 469 | return HandlersOutlined; |
| 470 | } |
| 471 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 472 | bool WinEHPrepare::outlineHandler(HandlerType CatchOrCleanup, Function *SrcFn, |
| 473 | Constant *SelectorType, LandingPadInst *LPad, |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 474 | CallInst *&EHAlloc, |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 475 | FrameVarInfoMap &VarInfo) { |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 476 | Module *M = SrcFn->getParent(); |
| 477 | LLVMContext &Context = M->getContext(); |
| 478 | |
| 479 | // Create a new function to receive the handler contents. |
| 480 | Type *Int8PtrType = Type::getInt8PtrTy(Context); |
| 481 | std::vector<Type *> ArgTys; |
| 482 | ArgTys.push_back(Int8PtrType); |
| 483 | ArgTys.push_back(Int8PtrType); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 484 | Function *Handler; |
| 485 | if (CatchOrCleanup == Catch) { |
| 486 | FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false); |
| 487 | Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| 488 | SrcFn->getName() + ".catch", M); |
| 489 | } else { |
| 490 | FunctionType *FnType = |
| 491 | FunctionType::get(Type::getVoidTy(Context), ArgTys, false); |
| 492 | Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| 493 | SrcFn->getName() + ".cleanup", M); |
| 494 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 495 | |
| 496 | // Generate a standard prolog to setup the frame recovery structure. |
| 497 | IRBuilder<> Builder(Context); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 498 | BasicBlock *Entry = BasicBlock::Create(Context, "entry"); |
| 499 | Handler->getBasicBlockList().push_front(Entry); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 500 | Builder.SetInsertPoint(Entry); |
| 501 | Builder.SetCurrentDebugLocation(LPad->getDebugLoc()); |
| 502 | |
| 503 | // The outlined handler will be called with the parent's frame pointer as |
| 504 | // its second argument. To enable the handler to access variables from |
| 505 | // the parent frame, we use that pointer to get locate a special block |
| 506 | // of memory that was allocated using llvm.eh.allocateframe for this |
| 507 | // purpose. During the outlining process we will determine which frame |
| 508 | // variables are used in handlers and create a structure that maps these |
| 509 | // variables into the frame allocation block. |
| 510 | // |
| 511 | // The frame allocation block also contains an exception state variable |
| 512 | // used by the runtime and a pointer to the exception object pointer |
| 513 | // which will be filled in by the runtime for use in the handler. |
| 514 | Function *RecoverFrameFn = |
| 515 | Intrinsic::getDeclaration(M, Intrinsic::framerecover); |
| 516 | Value *RecoverArgs[] = {Builder.CreateBitCast(SrcFn, Int8PtrType, ""), |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 517 | &(Handler->getArgumentList().back())}; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 518 | EHAlloc = Builder.CreateCall(RecoverFrameFn, RecoverArgs, "eh.alloc"); |
| 519 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 520 | std::unique_ptr<WinEHCloningDirectorBase> Director; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 521 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 522 | if (CatchOrCleanup == Catch) { |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 523 | Director.reset( |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 524 | new WinEHCatchDirector(LPad, Handler, SelectorType, VarInfo)); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 525 | } else { |
| 526 | Director.reset(new WinEHCleanupDirector(LPad, Handler, VarInfo)); |
| 527 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 528 | |
| 529 | ValueToValueMapTy VMap; |
| 530 | |
| 531 | // FIXME: Map other values referenced in the filter handler. |
| 532 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 533 | SmallVector<ReturnInst *, 8> Returns; |
| 534 | ClonedCodeInfo InlinedFunctionInfo; |
| 535 | |
| 536 | BasicBlock::iterator II = LPad; |
| 537 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 538 | CloneAndPruneIntoFromInst( |
| 539 | Handler, SrcFn, ++II, VMap, |
| 540 | /*ModuleLevelChanges=*/false, Returns, "", &InlinedFunctionInfo, |
| 541 | SrcFn->getParent()->getDataLayout(), Director.get()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 542 | |
| 543 | // Move all the instructions in the first cloned block into our entry block. |
| 544 | BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry)); |
| 545 | Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList()); |
| 546 | FirstClonedBB->eraseFromParent(); |
| 547 | |
| 548 | return true; |
| 549 | } |
| 550 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 551 | CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction( |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 552 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 553 | // Intercept instructions which extract values from the landing pad aggregate. |
| 554 | if (auto *Extract = dyn_cast<ExtractValueInst>(Inst)) { |
| 555 | if (Extract->getAggregateOperand() == LPI) { |
| 556 | assert(Extract->getNumIndices() == 1 && |
| 557 | "Unexpected operation: extracting both landing pad values"); |
| 558 | assert((*(Extract->idx_begin()) == 0 || *(Extract->idx_begin()) == 1) && |
| 559 | "Unexpected operation: extracting an unknown landing pad element"); |
| 560 | |
| 561 | if (*(Extract->idx_begin()) == 0) { |
| 562 | // Element 0 doesn't directly corresponds to anything in the WinEH |
| 563 | // scheme. |
| 564 | // It will be stored to a memory location, then later loaded and finally |
| 565 | // the loaded value will be used as the argument to an |
| 566 | // llvm.eh.begincatch |
| 567 | // call. We're tracking it here so that we can skip the store and load. |
| 568 | ExtractedEHPtr = Inst; |
| 569 | } else { |
| 570 | // Element 1 corresponds to the filter selector. We'll map it to 1 for |
| 571 | // matching purposes, but it will also probably be stored to memory and |
| 572 | // reloaded, so we need to track the instuction so that we can map the |
| 573 | // loaded value too. |
| 574 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 575 | ExtractedSelector = Inst; |
| 576 | } |
| 577 | |
| 578 | // Tell the caller not to clone this instruction. |
| 579 | return CloningDirector::SkipInstruction; |
| 580 | } |
| 581 | // Other extract value instructions just get cloned. |
| 582 | return CloningDirector::CloneInstruction; |
| 583 | } |
| 584 | |
| 585 | if (auto *Store = dyn_cast<StoreInst>(Inst)) { |
| 586 | // Look for and suppress stores of the extracted landingpad values. |
| 587 | const Value *StoredValue = Store->getValueOperand(); |
| 588 | if (StoredValue == ExtractedEHPtr) { |
| 589 | EHPtrStoreAddr = Store->getPointerOperand(); |
| 590 | return CloningDirector::SkipInstruction; |
| 591 | } |
| 592 | if (StoredValue == ExtractedSelector) { |
| 593 | SelectorStoreAddr = Store->getPointerOperand(); |
| 594 | return CloningDirector::SkipInstruction; |
| 595 | } |
| 596 | |
| 597 | // Any other store just gets cloned. |
| 598 | return CloningDirector::CloneInstruction; |
| 599 | } |
| 600 | |
| 601 | if (auto *Load = dyn_cast<LoadInst>(Inst)) { |
| 602 | // Look for loads of (previously suppressed) landingpad values. |
| 603 | // The EHPtr load can be ignored (it should only be used as |
| 604 | // an argument to llvm.eh.begincatch), but the selector value |
| 605 | // needs to be mapped to a constant value of 1 to be used to |
| 606 | // simplify the branching to always flow to the current handler. |
| 607 | const Value *LoadAddr = Load->getPointerOperand(); |
| 608 | if (LoadAddr == EHPtrStoreAddr) { |
| 609 | VMap[Inst] = UndefValue::get(Int8PtrType); |
| 610 | return CloningDirector::SkipInstruction; |
| 611 | } |
| 612 | if (LoadAddr == SelectorStoreAddr) { |
| 613 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 614 | return CloningDirector::SkipInstruction; |
| 615 | } |
| 616 | |
| 617 | // Any other loads just get cloned. |
| 618 | return CloningDirector::CloneInstruction; |
| 619 | } |
| 620 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 621 | if (auto *Resume = dyn_cast<ResumeInst>(Inst)) |
| 622 | return handleResume(VMap, Resume, NewBB); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 623 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 624 | if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) |
| 625 | return handleBeginCatch(VMap, Inst, NewBB); |
| 626 | if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) |
| 627 | return handleEndCatch(VMap, Inst, NewBB); |
| 628 | if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) |
| 629 | return handleTypeIdFor(VMap, Inst, NewBB); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 630 | |
| 631 | // Continue with the default cloning behavior. |
| 632 | return CloningDirector::CloneInstruction; |
| 633 | } |
| 634 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 635 | CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch( |
| 636 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 637 | // The argument to the call is some form of the first element of the |
| 638 | // landingpad aggregate value, but that doesn't matter. It isn't used |
| 639 | // here. |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame^] | 640 | // The second argument is an outparameter where the exception object will be |
| 641 | // stored. Typically the exception object is a scalar, but it can be an |
| 642 | // aggregate when catching by value. |
| 643 | // FIXME: Leave something behind to indicate where the exception object lives |
| 644 | // for this handler. Should it be part of llvm.eh.actions? |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 645 | return CloningDirector::SkipInstruction; |
| 646 | } |
| 647 | |
| 648 | CloningDirector::CloningAction |
| 649 | WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap, |
| 650 | const Instruction *Inst, BasicBlock *NewBB) { |
| 651 | auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst); |
| 652 | // It might be interesting to track whether or not we are inside a catch |
| 653 | // function, but that might make the algorithm more brittle than it needs |
| 654 | // to be. |
| 655 | |
| 656 | // The end catch call can occur in one of two places: either in a |
| 657 | // landingpad |
| 658 | // block that is part of the catch handlers exception mechanism, or at the |
| 659 | // end of the catch block. If it occurs in a landing pad, we must skip it |
| 660 | // and continue so that the landing pad gets cloned. |
| 661 | // FIXME: This case isn't fully supported yet and shouldn't turn up in any |
| 662 | // of the test cases until it is. |
| 663 | if (IntrinCall->getParent()->isLandingPad()) |
| 664 | return CloningDirector::SkipInstruction; |
| 665 | |
| 666 | // If an end catch occurs anywhere else the next instruction should be an |
| 667 | // unconditional branch instruction that we want to replace with a return |
| 668 | // to the the address of the branch target. |
| 669 | const BasicBlock *EndCatchBB = IntrinCall->getParent(); |
| 670 | const TerminatorInst *Terminator = EndCatchBB->getTerminator(); |
| 671 | const BranchInst *Branch = dyn_cast<BranchInst>(Terminator); |
| 672 | assert(Branch && Branch->isUnconditional()); |
| 673 | assert(std::next(BasicBlock::const_iterator(IntrinCall)) == |
| 674 | BasicBlock::const_iterator(Branch)); |
| 675 | |
| 676 | ReturnInst::Create(NewBB->getContext(), |
| 677 | BlockAddress::get(Branch->getSuccessor(0)), NewBB); |
| 678 | |
| 679 | // We just added a terminator to the cloned block. |
| 680 | // Tell the caller to stop processing the current basic block so that |
| 681 | // the branch instruction will be skipped. |
| 682 | return CloningDirector::StopCloningBB; |
| 683 | } |
| 684 | |
| 685 | CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor( |
| 686 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 687 | auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst); |
| 688 | Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts(); |
| 689 | // This causes a replacement that will collapse the landing pad CFG based |
| 690 | // on the filter function we intend to match. |
| 691 | if (Selector == CurrentSelector) |
| 692 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 693 | else |
| 694 | VMap[Inst] = ConstantInt::get(SelectorIDType, 0); |
| 695 | // Tell the caller not to clone this instruction. |
| 696 | return CloningDirector::SkipInstruction; |
| 697 | } |
| 698 | |
| 699 | CloningDirector::CloningAction |
| 700 | WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap, |
| 701 | const ResumeInst *Resume, BasicBlock *NewBB) { |
| 702 | // Resume instructions shouldn't be reachable from catch handlers. |
| 703 | // We still need to handle it, but it will be pruned. |
| 704 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 705 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 706 | return CloningDirector::StopCloningBB; |
| 707 | } |
| 708 | |
| 709 | CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch( |
| 710 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 711 | // Catch blocks within cleanup handlers will always be unreachable. |
| 712 | // We'll insert an unreachable instruction now, but it will be pruned |
| 713 | // before the cloning process is complete. |
| 714 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 715 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 716 | return CloningDirector::StopCloningBB; |
| 717 | } |
| 718 | |
| 719 | CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch( |
| 720 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 721 | // Catch blocks within cleanup handlers will always be unreachable. |
| 722 | // We'll insert an unreachable instruction now, but it will be pruned |
| 723 | // before the cloning process is complete. |
| 724 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 725 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 726 | return CloningDirector::StopCloningBB; |
| 727 | } |
| 728 | |
| 729 | CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor( |
| 730 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 731 | // This causes a replacement that will collapse the landing pad CFG |
| 732 | // to just the cleanup code. |
| 733 | VMap[Inst] = ConstantInt::get(SelectorIDType, 0); |
| 734 | // Tell the caller not to clone this instruction. |
| 735 | return CloningDirector::SkipInstruction; |
| 736 | } |
| 737 | |
| 738 | CloningDirector::CloningAction WinEHCleanupDirector::handleResume( |
| 739 | ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) { |
| 740 | ReturnInst::Create(NewBB->getContext(), nullptr, NewBB); |
| 741 | |
| 742 | // We just added a terminator to the cloned block. |
| 743 | // Tell the caller to stop processing the current basic block so that |
| 744 | // the branch instruction will be skipped. |
| 745 | return CloningDirector::StopCloningBB; |
| 746 | } |
| 747 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 748 | WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer( |
| 749 | Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo) |
| 750 | : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) { |
| 751 | Builder.SetInsertPoint(&OutlinedFn->getEntryBlock()); |
| 752 | // FIXME: Do something with the FrameVarMapped so that it is shared across the |
| 753 | // function. |
| 754 | } |
| 755 | |
| 756 | Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 757 | // If we're asked to materialize a value that is an instruction, we |
| 758 | // temporarily create an alloca in the outlined function and add this |
| 759 | // to the FrameVarInfo map. When all the outlining is complete, we'll |
| 760 | // collect these into a structure, spilling non-alloca values in the |
| 761 | // parent frame as necessary, and replace these temporary allocas with |
| 762 | // GEPs referencing the frame allocation block. |
| 763 | |
| 764 | // If the value is an alloca, the mapping is direct. |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 765 | if (auto *AV = dyn_cast<AllocaInst>(V)) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 766 | AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone()); |
| 767 | Builder.Insert(NewAlloca, AV->getName()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 768 | FrameVarInfo[AV].Allocas.push_back(NewAlloca); |
| 769 | return NewAlloca; |
| 770 | } |
| 771 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 772 | // For other types of instructions or arguments, we need an alloca based on |
| 773 | // the value's type and a load of the alloca. The alloca will be replaced |
| 774 | // by a GEP, but the load will stay. In the parent function, the value will |
| 775 | // be spilled to a location in the frame allocation block. |
| 776 | if (isa<Instruction>(V) || isa<Argument>(V)) { |
| 777 | AllocaInst *NewAlloca = |
| 778 | Builder.CreateAlloca(V->getType(), nullptr, "eh.temp.alloca"); |
| 779 | FrameVarInfo[V].Allocas.push_back(NewAlloca); |
| 780 | LoadInst *NewLoad = Builder.CreateLoad(NewAlloca, V->getName() + ".reload"); |
| 781 | return NewLoad; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 782 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 783 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 784 | // Don't materialize other values. |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 785 | return nullptr; |
| 786 | } |