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 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 39 | // This map is used to model frame variable usage during outlining, to |
| 40 | // construct a structure type to hold the frame variables in a frame |
| 41 | // allocation block, and to remap the frame variable allocas (including |
| 42 | // spill locations as needed) to GEPs that get the variable from the |
| 43 | // frame allocation structure. |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 44 | typedef MapVector<Value *, TinyPtrVector<AllocaInst *>> FrameVarInfoMap; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 45 | |
| 46 | class WinEHPrepare : public FunctionPass { |
| 47 | std::unique_ptr<FunctionPass> DwarfPrepare; |
| 48 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 49 | enum HandlerType { Catch, Cleanup }; |
| 50 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 51 | public: |
| 52 | static char ID; // Pass identification, replacement for typeid. |
| 53 | WinEHPrepare(const TargetMachine *TM = nullptr) |
| 54 | : FunctionPass(ID), DwarfPrepare(createDwarfEHPass(TM)) {} |
| 55 | |
| 56 | bool runOnFunction(Function &Fn) override; |
| 57 | |
| 58 | bool doFinalization(Module &M) override; |
| 59 | |
| 60 | void getAnalysisUsage(AnalysisUsage &AU) const override; |
| 61 | |
| 62 | const char *getPassName() const override { |
| 63 | return "Windows exception handling preparation"; |
| 64 | } |
| 65 | |
| 66 | private: |
| 67 | bool prepareCPPEHHandlers(Function &F, |
| 68 | SmallVectorImpl<LandingPadInst *> &LPads); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 69 | bool outlineHandler(HandlerType CatchOrCleanup, Function *SrcFn, |
| 70 | Constant *SelectorType, LandingPadInst *LPad, |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 71 | FrameVarInfoMap &VarInfo); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 72 | }; |
| 73 | |
| 74 | class WinEHFrameVariableMaterializer : public ValueMaterializer { |
| 75 | public: |
| 76 | WinEHFrameVariableMaterializer(Function *OutlinedFn, |
| 77 | FrameVarInfoMap &FrameVarInfo); |
| 78 | ~WinEHFrameVariableMaterializer() {} |
| 79 | |
| 80 | virtual Value *materializeValueFor(Value *V) override; |
| 81 | |
| 82 | private: |
| 83 | FrameVarInfoMap &FrameVarInfo; |
| 84 | IRBuilder<> Builder; |
| 85 | }; |
| 86 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 87 | class WinEHCloningDirectorBase : public CloningDirector { |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 88 | public: |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 89 | WinEHCloningDirectorBase(LandingPadInst *LPI, Function *HandlerFn, |
| 90 | FrameVarInfoMap &VarInfo) |
| 91 | : LPI(LPI), Materializer(HandlerFn, VarInfo), |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 92 | SelectorIDType(Type::getInt32Ty(LPI->getContext())), |
Andrew Kaylor | 05ee8bd | 2015-03-05 21:06:42 +0000 | [diff] [blame] | 93 | Int8PtrType(Type::getInt8PtrTy(LPI->getContext())), |
| 94 | ExtractedEHPtr(nullptr), ExtractedSelector(nullptr), |
| 95 | EHPtrStoreAddr(nullptr), SelectorStoreAddr(nullptr) {} |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 96 | |
| 97 | CloningAction handleInstruction(ValueToValueMapTy &VMap, |
| 98 | const Instruction *Inst, |
| 99 | BasicBlock *NewBB) override; |
| 100 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 101 | virtual CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 102 | const Instruction *Inst, |
| 103 | BasicBlock *NewBB) = 0; |
| 104 | virtual CloningAction handleEndCatch(ValueToValueMapTy &VMap, |
| 105 | const Instruction *Inst, |
| 106 | BasicBlock *NewBB) = 0; |
| 107 | virtual CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 108 | const Instruction *Inst, |
| 109 | BasicBlock *NewBB) = 0; |
| 110 | virtual CloningAction handleResume(ValueToValueMapTy &VMap, |
| 111 | const ResumeInst *Resume, |
| 112 | BasicBlock *NewBB) = 0; |
| 113 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 114 | ValueMaterializer *getValueMaterializer() override { return &Materializer; } |
| 115 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 116 | protected: |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 117 | LandingPadInst *LPI; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 118 | WinEHFrameVariableMaterializer Materializer; |
| 119 | Type *SelectorIDType; |
| 120 | Type *Int8PtrType; |
| 121 | |
| 122 | const Value *ExtractedEHPtr; |
| 123 | const Value *ExtractedSelector; |
| 124 | const Value *EHPtrStoreAddr; |
| 125 | const Value *SelectorStoreAddr; |
| 126 | }; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 127 | |
| 128 | class WinEHCatchDirector : public WinEHCloningDirectorBase { |
| 129 | public: |
| 130 | WinEHCatchDirector(LandingPadInst *LPI, Function *CatchFn, Value *Selector, |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame] | 131 | FrameVarInfoMap &VarInfo) |
Andrew Kaylor | e07b2a0 | 2015-03-03 20:22:09 +0000 | [diff] [blame] | 132 | : WinEHCloningDirectorBase(LPI, CatchFn, VarInfo), |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame] | 133 | CurrentSelector(Selector->stripPointerCasts()) {} |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 134 | |
| 135 | CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 136 | const Instruction *Inst, |
| 137 | BasicBlock *NewBB) override; |
| 138 | CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| 139 | BasicBlock *NewBB) override; |
| 140 | CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 141 | const Instruction *Inst, |
| 142 | BasicBlock *NewBB) override; |
| 143 | CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| 144 | BasicBlock *NewBB) override; |
| 145 | |
| 146 | private: |
| 147 | Value *CurrentSelector; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 148 | }; |
| 149 | |
| 150 | class WinEHCleanupDirector : public WinEHCloningDirectorBase { |
| 151 | public: |
| 152 | WinEHCleanupDirector(LandingPadInst *LPI, Function *CleanupFn, |
| 153 | FrameVarInfoMap &VarInfo) |
| 154 | : WinEHCloningDirectorBase(LPI, CleanupFn, VarInfo) {} |
| 155 | |
| 156 | CloningAction handleBeginCatch(ValueToValueMapTy &VMap, |
| 157 | const Instruction *Inst, |
| 158 | BasicBlock *NewBB) override; |
| 159 | CloningAction handleEndCatch(ValueToValueMapTy &VMap, const Instruction *Inst, |
| 160 | BasicBlock *NewBB) override; |
| 161 | CloningAction handleTypeIdFor(ValueToValueMapTy &VMap, |
| 162 | const Instruction *Inst, |
| 163 | BasicBlock *NewBB) override; |
| 164 | CloningAction handleResume(ValueToValueMapTy &VMap, const ResumeInst *Resume, |
| 165 | BasicBlock *NewBB) override; |
| 166 | }; |
| 167 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 168 | } // end anonymous namespace |
| 169 | |
| 170 | char WinEHPrepare::ID = 0; |
| 171 | INITIALIZE_TM_PASS(WinEHPrepare, "winehprepare", "Prepare Windows exceptions", |
| 172 | false, false) |
| 173 | |
| 174 | FunctionPass *llvm::createWinEHPass(const TargetMachine *TM) { |
| 175 | return new WinEHPrepare(TM); |
| 176 | } |
| 177 | |
| 178 | static bool isMSVCPersonality(EHPersonality Pers) { |
| 179 | return Pers == EHPersonality::MSVC_Win64SEH || |
| 180 | Pers == EHPersonality::MSVC_CXX; |
| 181 | } |
| 182 | |
| 183 | bool WinEHPrepare::runOnFunction(Function &Fn) { |
| 184 | SmallVector<LandingPadInst *, 4> LPads; |
| 185 | SmallVector<ResumeInst *, 4> Resumes; |
| 186 | for (BasicBlock &BB : Fn) { |
| 187 | if (auto *LP = BB.getLandingPadInst()) |
| 188 | LPads.push_back(LP); |
| 189 | if (auto *Resume = dyn_cast<ResumeInst>(BB.getTerminator())) |
| 190 | Resumes.push_back(Resume); |
| 191 | } |
| 192 | |
| 193 | // No need to prepare functions that lack landing pads. |
| 194 | if (LPads.empty()) |
| 195 | return false; |
| 196 | |
| 197 | // Classify the personality to see what kind of preparation we need. |
| 198 | EHPersonality Pers = classifyEHPersonality(LPads.back()->getPersonalityFn()); |
| 199 | |
| 200 | // Delegate through to the DWARF pass if this is unrecognized. |
| 201 | if (!isMSVCPersonality(Pers)) |
| 202 | return DwarfPrepare->runOnFunction(Fn); |
| 203 | |
| 204 | // FIXME: This only returns true if the C++ EH handlers were outlined. |
| 205 | // When that code is complete, it should always return whatever |
| 206 | // prepareCPPEHHandlers returns. |
| 207 | if (Pers == EHPersonality::MSVC_CXX && prepareCPPEHHandlers(Fn, LPads)) |
| 208 | return true; |
| 209 | |
| 210 | // FIXME: SEH Cleanups are unimplemented. Replace them with unreachable. |
| 211 | if (Resumes.empty()) |
| 212 | return false; |
| 213 | |
| 214 | for (ResumeInst *Resume : Resumes) { |
| 215 | IRBuilder<>(Resume).CreateUnreachable(); |
| 216 | Resume->eraseFromParent(); |
| 217 | } |
| 218 | |
| 219 | return true; |
| 220 | } |
| 221 | |
| 222 | bool WinEHPrepare::doFinalization(Module &M) { |
| 223 | return DwarfPrepare->doFinalization(M); |
| 224 | } |
| 225 | |
| 226 | void WinEHPrepare::getAnalysisUsage(AnalysisUsage &AU) const { |
| 227 | DwarfPrepare->getAnalysisUsage(AU); |
| 228 | } |
| 229 | |
| 230 | bool WinEHPrepare::prepareCPPEHHandlers( |
| 231 | Function &F, SmallVectorImpl<LandingPadInst *> &LPads) { |
| 232 | // These containers are used to re-map frame variables that are used in |
| 233 | // outlined catch and cleanup handlers. They will be populated as the |
| 234 | // handlers are outlined. |
| 235 | FrameVarInfoMap FrameVarInfo; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 236 | |
| 237 | bool HandlersOutlined = false; |
| 238 | |
| 239 | for (LandingPadInst *LPad : LPads) { |
| 240 | // Look for evidence that this landingpad has already been processed. |
| 241 | bool LPadHasActionList = false; |
| 242 | BasicBlock *LPadBB = LPad->getParent(); |
| 243 | for (Instruction &Inst : LPadBB->getInstList()) { |
| 244 | // FIXME: Make this an intrinsic. |
| 245 | if (auto *Call = dyn_cast<CallInst>(&Inst)) |
| 246 | if (Call->getCalledFunction()->getName() == "llvm.eh.actions") { |
| 247 | LPadHasActionList = true; |
| 248 | break; |
| 249 | } |
| 250 | } |
| 251 | |
| 252 | // If we've already outlined the handlers for this landingpad, |
| 253 | // there's nothing more to do here. |
| 254 | if (LPadHasActionList) |
| 255 | continue; |
| 256 | |
| 257 | for (unsigned Idx = 0, NumClauses = LPad->getNumClauses(); Idx < NumClauses; |
| 258 | ++Idx) { |
| 259 | if (LPad->isCatch(Idx)) { |
| 260 | // Create a new instance of the handler data structure in the |
| 261 | // HandlerData vector. |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 262 | bool Outlined = outlineHandler(Catch, &F, LPad->getClause(Idx), LPad, |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 263 | FrameVarInfo); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 264 | if (Outlined) { |
| 265 | HandlersOutlined = true; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 266 | } |
| 267 | } // End if (isCatch) |
| 268 | } // End for each clause |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 269 | |
| 270 | // FIXME: This only handles the simple case where there is a 1:1 |
| 271 | // correspondence between landing pad and cleanup blocks. |
| 272 | // It does not handle cases where there are catch blocks between |
| 273 | // cleanup blocks or the case where a cleanup block is shared by |
| 274 | // multiple landing pads. Those cases will be supported later |
| 275 | // when landing pad block analysis is added. |
| 276 | if (LPad->isCleanup()) { |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame] | 277 | bool Outlined = |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 278 | outlineHandler(Cleanup, &F, nullptr, LPad, FrameVarInfo); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 279 | if (Outlined) { |
| 280 | HandlersOutlined = true; |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 281 | } |
| 282 | } |
| 283 | } // End for each landingpad |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 284 | |
| 285 | // If nothing got outlined, there is no more processing to be done. |
| 286 | if (!HandlersOutlined) |
| 287 | return false; |
| 288 | |
| 289 | // FIXME: We will replace the landingpad bodies with llvm.eh.actions |
| 290 | // calls and indirect branches here and then delete blocks |
| 291 | // which are no longer reachable. That will get rid of the |
| 292 | // handlers that we have outlined. There is code below |
| 293 | // that looks for allocas with no uses in the parent function. |
| 294 | // That will only happen after the pruning is implemented. |
| 295 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 296 | Module *M = F.getParent(); |
| 297 | LLVMContext &Context = M->getContext(); |
| 298 | BasicBlock *Entry = &F.getEntryBlock(); |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 299 | IRBuilder<> Builder(F.getParent()->getContext()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 300 | Builder.SetInsertPoint(Entry->getFirstInsertionPt()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 301 | |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 302 | Function *FrameEscapeFn = |
| 303 | Intrinsic::getDeclaration(M, Intrinsic::frameescape); |
| 304 | Function *RecoverFrameFn = |
| 305 | Intrinsic::getDeclaration(M, Intrinsic::framerecover); |
| 306 | Type *Int8PtrType = Type::getInt8PtrTy(Context); |
| 307 | Type *Int32Type = Type::getInt32Ty(Context); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 308 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 309 | // Finally, replace all of the temporary allocas for frame variables used in |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 310 | // the outlined handlers with calls to llvm.framerecover. |
| 311 | BasicBlock::iterator II = Entry->getFirstInsertionPt(); |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 312 | Instruction *AllocaInsertPt = II; |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 313 | SmallVector<Value *, 8> AllocasToEscape; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 314 | for (auto &VarInfoEntry : FrameVarInfo) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 315 | Value *ParentVal = VarInfoEntry.first; |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 316 | TinyPtrVector<AllocaInst *> &Allocas = VarInfoEntry.second; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 317 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 318 | // If the mapped value isn't already an alloca, we need to spill it if it |
| 319 | // is a computed value or copy it if it is an argument. |
| 320 | AllocaInst *ParentAlloca = dyn_cast<AllocaInst>(ParentVal); |
| 321 | if (!ParentAlloca) { |
| 322 | if (auto *Arg = dyn_cast<Argument>(ParentVal)) { |
| 323 | // Lower this argument to a copy and then demote that to the stack. |
| 324 | // We can't just use the argument location because the handler needs |
| 325 | // it to be in the frame allocation block. |
| 326 | // Use 'select i8 true, %arg, undef' to simulate a 'no-op' instruction. |
| 327 | Value *TrueValue = ConstantInt::getTrue(Context); |
| 328 | Value *UndefValue = UndefValue::get(Arg->getType()); |
| 329 | Instruction *SI = |
| 330 | SelectInst::Create(TrueValue, Arg, UndefValue, |
| 331 | Arg->getName() + ".tmp", AllocaInsertPt); |
| 332 | Arg->replaceAllUsesWith(SI); |
| 333 | // Reset the select operand, because it was clobbered by the RAUW above. |
| 334 | SI->setOperand(1, Arg); |
| 335 | ParentAlloca = DemoteRegToStack(*SI, true, SI); |
| 336 | } else if (auto *PN = dyn_cast<PHINode>(ParentVal)) { |
| 337 | ParentAlloca = DemotePHIToStack(PN, AllocaInsertPt); |
| 338 | } else { |
| 339 | Instruction *ParentInst = cast<Instruction>(ParentVal); |
| 340 | ParentAlloca = DemoteRegToStack(*ParentInst, true, ParentInst); |
| 341 | } |
| 342 | } |
| 343 | |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 344 | // If the parent alloca is no longer used and only one of the handlers used |
| 345 | // it, erase the parent and leave the copy in the outlined handler. |
| 346 | if (ParentAlloca->getNumUses() == 0 && Allocas.size() == 1) { |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 347 | ParentAlloca->eraseFromParent(); |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 348 | continue; |
| 349 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 350 | |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 351 | // Add this alloca to the list of things to escape. |
| 352 | AllocasToEscape.push_back(ParentAlloca); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 353 | |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 354 | // Next replace all outlined allocas that are mapped to it. |
| 355 | for (AllocaInst *TempAlloca : Allocas) { |
| 356 | Function *HandlerFn = TempAlloca->getParent()->getParent(); |
| 357 | // FIXME: Sink this GEP into the blocks where it is used. |
| 358 | Builder.SetInsertPoint(TempAlloca); |
| 359 | Builder.SetCurrentDebugLocation(TempAlloca->getDebugLoc()); |
| 360 | Value *RecoverArgs[] = { |
| 361 | Builder.CreateBitCast(&F, Int8PtrType, ""), |
| 362 | &(HandlerFn->getArgumentList().back()), |
| 363 | llvm::ConstantInt::get(Int32Type, AllocasToEscape.size() - 1)}; |
| 364 | Value *RecoveredAlloca = |
| 365 | Builder.CreateCall(RecoverFrameFn, RecoverArgs); |
| 366 | // Add a pointer bitcast if the alloca wasn't an i8. |
| 367 | if (RecoveredAlloca->getType() != TempAlloca->getType()) { |
| 368 | RecoveredAlloca->setName(Twine(TempAlloca->getName()) + ".i8"); |
| 369 | RecoveredAlloca = |
| 370 | Builder.CreateBitCast(RecoveredAlloca, TempAlloca->getType()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 371 | } |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 372 | TempAlloca->replaceAllUsesWith(RecoveredAlloca); |
| 373 | TempAlloca->removeFromParent(); |
| 374 | RecoveredAlloca->takeName(TempAlloca); |
| 375 | delete TempAlloca; |
| 376 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 377 | } // End for each FrameVarInfo entry. |
| 378 | |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 379 | // Insert 'call void (...)* @llvm.frameescape(...)' at the end of the entry |
| 380 | // block. |
| 381 | Builder.SetInsertPoint(&F.getEntryBlock().back()); |
| 382 | Builder.CreateCall(FrameEscapeFn, AllocasToEscape); |
| 383 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 384 | return HandlersOutlined; |
| 385 | } |
| 386 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 387 | bool WinEHPrepare::outlineHandler(HandlerType CatchOrCleanup, Function *SrcFn, |
| 388 | Constant *SelectorType, LandingPadInst *LPad, |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 389 | FrameVarInfoMap &VarInfo) { |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 390 | Module *M = SrcFn->getParent(); |
| 391 | LLVMContext &Context = M->getContext(); |
| 392 | |
| 393 | // Create a new function to receive the handler contents. |
| 394 | Type *Int8PtrType = Type::getInt8PtrTy(Context); |
| 395 | std::vector<Type *> ArgTys; |
| 396 | ArgTys.push_back(Int8PtrType); |
| 397 | ArgTys.push_back(Int8PtrType); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 398 | Function *Handler; |
| 399 | if (CatchOrCleanup == Catch) { |
| 400 | FunctionType *FnType = FunctionType::get(Int8PtrType, ArgTys, false); |
| 401 | Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| 402 | SrcFn->getName() + ".catch", M); |
| 403 | } else { |
| 404 | FunctionType *FnType = |
| 405 | FunctionType::get(Type::getVoidTy(Context), ArgTys, false); |
| 406 | Handler = Function::Create(FnType, GlobalVariable::InternalLinkage, |
| 407 | SrcFn->getName() + ".cleanup", M); |
| 408 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 409 | |
| 410 | // Generate a standard prolog to setup the frame recovery structure. |
| 411 | IRBuilder<> Builder(Context); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 412 | BasicBlock *Entry = BasicBlock::Create(Context, "entry"); |
| 413 | Handler->getBasicBlockList().push_front(Entry); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 414 | Builder.SetInsertPoint(Entry); |
| 415 | Builder.SetCurrentDebugLocation(LPad->getDebugLoc()); |
| 416 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 417 | std::unique_ptr<WinEHCloningDirectorBase> Director; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 418 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 419 | if (CatchOrCleanup == Catch) { |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 420 | Director.reset( |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame] | 421 | new WinEHCatchDirector(LPad, Handler, SelectorType, VarInfo)); |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 422 | } else { |
| 423 | Director.reset(new WinEHCleanupDirector(LPad, Handler, VarInfo)); |
| 424 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 425 | |
| 426 | ValueToValueMapTy VMap; |
| 427 | |
| 428 | // FIXME: Map other values referenced in the filter handler. |
| 429 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 430 | SmallVector<ReturnInst *, 8> Returns; |
| 431 | ClonedCodeInfo InlinedFunctionInfo; |
| 432 | |
| 433 | BasicBlock::iterator II = LPad; |
| 434 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 435 | CloneAndPruneIntoFromInst( |
| 436 | Handler, SrcFn, ++II, VMap, |
| 437 | /*ModuleLevelChanges=*/false, Returns, "", &InlinedFunctionInfo, |
Mehdi Amini | 46a4355 | 2015-03-04 18:43:29 +0000 | [diff] [blame] | 438 | &SrcFn->getParent()->getDataLayout(), Director.get()); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 439 | |
| 440 | // Move all the instructions in the first cloned block into our entry block. |
| 441 | BasicBlock *FirstClonedBB = std::next(Function::iterator(Entry)); |
| 442 | Entry->getInstList().splice(Entry->end(), FirstClonedBB->getInstList()); |
| 443 | FirstClonedBB->eraseFromParent(); |
| 444 | |
| 445 | return true; |
| 446 | } |
| 447 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 448 | CloningDirector::CloningAction WinEHCloningDirectorBase::handleInstruction( |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 449 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 450 | // Intercept instructions which extract values from the landing pad aggregate. |
| 451 | if (auto *Extract = dyn_cast<ExtractValueInst>(Inst)) { |
| 452 | if (Extract->getAggregateOperand() == LPI) { |
| 453 | assert(Extract->getNumIndices() == 1 && |
| 454 | "Unexpected operation: extracting both landing pad values"); |
| 455 | assert((*(Extract->idx_begin()) == 0 || *(Extract->idx_begin()) == 1) && |
| 456 | "Unexpected operation: extracting an unknown landing pad element"); |
| 457 | |
| 458 | if (*(Extract->idx_begin()) == 0) { |
| 459 | // Element 0 doesn't directly corresponds to anything in the WinEH |
| 460 | // scheme. |
| 461 | // It will be stored to a memory location, then later loaded and finally |
| 462 | // the loaded value will be used as the argument to an |
| 463 | // llvm.eh.begincatch |
| 464 | // call. We're tracking it here so that we can skip the store and load. |
| 465 | ExtractedEHPtr = Inst; |
| 466 | } else { |
| 467 | // Element 1 corresponds to the filter selector. We'll map it to 1 for |
| 468 | // matching purposes, but it will also probably be stored to memory and |
| 469 | // reloaded, so we need to track the instuction so that we can map the |
| 470 | // loaded value too. |
| 471 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 472 | ExtractedSelector = Inst; |
| 473 | } |
| 474 | |
| 475 | // Tell the caller not to clone this instruction. |
| 476 | return CloningDirector::SkipInstruction; |
| 477 | } |
| 478 | // Other extract value instructions just get cloned. |
| 479 | return CloningDirector::CloneInstruction; |
| 480 | } |
| 481 | |
| 482 | if (auto *Store = dyn_cast<StoreInst>(Inst)) { |
| 483 | // Look for and suppress stores of the extracted landingpad values. |
| 484 | const Value *StoredValue = Store->getValueOperand(); |
| 485 | if (StoredValue == ExtractedEHPtr) { |
| 486 | EHPtrStoreAddr = Store->getPointerOperand(); |
| 487 | return CloningDirector::SkipInstruction; |
| 488 | } |
| 489 | if (StoredValue == ExtractedSelector) { |
| 490 | SelectorStoreAddr = Store->getPointerOperand(); |
| 491 | return CloningDirector::SkipInstruction; |
| 492 | } |
| 493 | |
| 494 | // Any other store just gets cloned. |
| 495 | return CloningDirector::CloneInstruction; |
| 496 | } |
| 497 | |
| 498 | if (auto *Load = dyn_cast<LoadInst>(Inst)) { |
| 499 | // Look for loads of (previously suppressed) landingpad values. |
| 500 | // The EHPtr load can be ignored (it should only be used as |
| 501 | // an argument to llvm.eh.begincatch), but the selector value |
| 502 | // needs to be mapped to a constant value of 1 to be used to |
| 503 | // simplify the branching to always flow to the current handler. |
| 504 | const Value *LoadAddr = Load->getPointerOperand(); |
| 505 | if (LoadAddr == EHPtrStoreAddr) { |
| 506 | VMap[Inst] = UndefValue::get(Int8PtrType); |
| 507 | return CloningDirector::SkipInstruction; |
| 508 | } |
| 509 | if (LoadAddr == SelectorStoreAddr) { |
| 510 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 511 | return CloningDirector::SkipInstruction; |
| 512 | } |
| 513 | |
| 514 | // Any other loads just get cloned. |
| 515 | return CloningDirector::CloneInstruction; |
| 516 | } |
| 517 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 518 | if (auto *Resume = dyn_cast<ResumeInst>(Inst)) |
| 519 | return handleResume(VMap, Resume, NewBB); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 520 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 521 | if (match(Inst, m_Intrinsic<Intrinsic::eh_begincatch>())) |
| 522 | return handleBeginCatch(VMap, Inst, NewBB); |
| 523 | if (match(Inst, m_Intrinsic<Intrinsic::eh_endcatch>())) |
| 524 | return handleEndCatch(VMap, Inst, NewBB); |
| 525 | if (match(Inst, m_Intrinsic<Intrinsic::eh_typeid_for>())) |
| 526 | return handleTypeIdFor(VMap, Inst, NewBB); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 527 | |
| 528 | // Continue with the default cloning behavior. |
| 529 | return CloningDirector::CloneInstruction; |
| 530 | } |
| 531 | |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 532 | CloningDirector::CloningAction WinEHCatchDirector::handleBeginCatch( |
| 533 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 534 | // The argument to the call is some form of the first element of the |
| 535 | // landingpad aggregate value, but that doesn't matter. It isn't used |
| 536 | // here. |
Reid Kleckner | 4236653 | 2015-03-03 23:20:30 +0000 | [diff] [blame] | 537 | // The second argument is an outparameter where the exception object will be |
| 538 | // stored. Typically the exception object is a scalar, but it can be an |
| 539 | // aggregate when catching by value. |
| 540 | // FIXME: Leave something behind to indicate where the exception object lives |
| 541 | // for this handler. Should it be part of llvm.eh.actions? |
Andrew Kaylor | f0f5e46 | 2015-03-03 20:00:16 +0000 | [diff] [blame] | 542 | return CloningDirector::SkipInstruction; |
| 543 | } |
| 544 | |
| 545 | CloningDirector::CloningAction |
| 546 | WinEHCatchDirector::handleEndCatch(ValueToValueMapTy &VMap, |
| 547 | const Instruction *Inst, BasicBlock *NewBB) { |
| 548 | auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst); |
| 549 | // It might be interesting to track whether or not we are inside a catch |
| 550 | // function, but that might make the algorithm more brittle than it needs |
| 551 | // to be. |
| 552 | |
| 553 | // The end catch call can occur in one of two places: either in a |
| 554 | // landingpad |
| 555 | // block that is part of the catch handlers exception mechanism, or at the |
| 556 | // end of the catch block. If it occurs in a landing pad, we must skip it |
| 557 | // and continue so that the landing pad gets cloned. |
| 558 | // FIXME: This case isn't fully supported yet and shouldn't turn up in any |
| 559 | // of the test cases until it is. |
| 560 | if (IntrinCall->getParent()->isLandingPad()) |
| 561 | return CloningDirector::SkipInstruction; |
| 562 | |
| 563 | // If an end catch occurs anywhere else the next instruction should be an |
| 564 | // unconditional branch instruction that we want to replace with a return |
| 565 | // to the the address of the branch target. |
| 566 | const BasicBlock *EndCatchBB = IntrinCall->getParent(); |
| 567 | const TerminatorInst *Terminator = EndCatchBB->getTerminator(); |
| 568 | const BranchInst *Branch = dyn_cast<BranchInst>(Terminator); |
| 569 | assert(Branch && Branch->isUnconditional()); |
| 570 | assert(std::next(BasicBlock::const_iterator(IntrinCall)) == |
| 571 | BasicBlock::const_iterator(Branch)); |
| 572 | |
| 573 | ReturnInst::Create(NewBB->getContext(), |
| 574 | BlockAddress::get(Branch->getSuccessor(0)), NewBB); |
| 575 | |
| 576 | // We just added a terminator to the cloned block. |
| 577 | // Tell the caller to stop processing the current basic block so that |
| 578 | // the branch instruction will be skipped. |
| 579 | return CloningDirector::StopCloningBB; |
| 580 | } |
| 581 | |
| 582 | CloningDirector::CloningAction WinEHCatchDirector::handleTypeIdFor( |
| 583 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 584 | auto *IntrinCall = dyn_cast<IntrinsicInst>(Inst); |
| 585 | Value *Selector = IntrinCall->getArgOperand(0)->stripPointerCasts(); |
| 586 | // This causes a replacement that will collapse the landing pad CFG based |
| 587 | // on the filter function we intend to match. |
| 588 | if (Selector == CurrentSelector) |
| 589 | VMap[Inst] = ConstantInt::get(SelectorIDType, 1); |
| 590 | else |
| 591 | VMap[Inst] = ConstantInt::get(SelectorIDType, 0); |
| 592 | // Tell the caller not to clone this instruction. |
| 593 | return CloningDirector::SkipInstruction; |
| 594 | } |
| 595 | |
| 596 | CloningDirector::CloningAction |
| 597 | WinEHCatchDirector::handleResume(ValueToValueMapTy &VMap, |
| 598 | const ResumeInst *Resume, BasicBlock *NewBB) { |
| 599 | // Resume instructions shouldn't be reachable from catch handlers. |
| 600 | // We still need to handle it, but it will be pruned. |
| 601 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 602 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 603 | return CloningDirector::StopCloningBB; |
| 604 | } |
| 605 | |
| 606 | CloningDirector::CloningAction WinEHCleanupDirector::handleBeginCatch( |
| 607 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 608 | // Catch blocks within cleanup handlers will always be unreachable. |
| 609 | // We'll insert an unreachable instruction now, but it will be pruned |
| 610 | // before the cloning process is complete. |
| 611 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 612 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 613 | return CloningDirector::StopCloningBB; |
| 614 | } |
| 615 | |
| 616 | CloningDirector::CloningAction WinEHCleanupDirector::handleEndCatch( |
| 617 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 618 | // Catch blocks within cleanup handlers will always be unreachable. |
| 619 | // We'll insert an unreachable instruction now, but it will be pruned |
| 620 | // before the cloning process is complete. |
| 621 | BasicBlock::InstListType &InstList = NewBB->getInstList(); |
| 622 | InstList.push_back(new UnreachableInst(NewBB->getContext())); |
| 623 | return CloningDirector::StopCloningBB; |
| 624 | } |
| 625 | |
| 626 | CloningDirector::CloningAction WinEHCleanupDirector::handleTypeIdFor( |
| 627 | ValueToValueMapTy &VMap, const Instruction *Inst, BasicBlock *NewBB) { |
| 628 | // This causes a replacement that will collapse the landing pad CFG |
| 629 | // to just the cleanup code. |
| 630 | VMap[Inst] = ConstantInt::get(SelectorIDType, 0); |
| 631 | // Tell the caller not to clone this instruction. |
| 632 | return CloningDirector::SkipInstruction; |
| 633 | } |
| 634 | |
| 635 | CloningDirector::CloningAction WinEHCleanupDirector::handleResume( |
| 636 | ValueToValueMapTy &VMap, const ResumeInst *Resume, BasicBlock *NewBB) { |
| 637 | ReturnInst::Create(NewBB->getContext(), nullptr, NewBB); |
| 638 | |
| 639 | // We just added a terminator to the cloned block. |
| 640 | // Tell the caller to stop processing the current basic block so that |
| 641 | // the branch instruction will be skipped. |
| 642 | return CloningDirector::StopCloningBB; |
| 643 | } |
| 644 | |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 645 | WinEHFrameVariableMaterializer::WinEHFrameVariableMaterializer( |
| 646 | Function *OutlinedFn, FrameVarInfoMap &FrameVarInfo) |
| 647 | : FrameVarInfo(FrameVarInfo), Builder(OutlinedFn->getContext()) { |
| 648 | Builder.SetInsertPoint(&OutlinedFn->getEntryBlock()); |
| 649 | // FIXME: Do something with the FrameVarMapped so that it is shared across the |
| 650 | // function. |
| 651 | } |
| 652 | |
| 653 | Value *WinEHFrameVariableMaterializer::materializeValueFor(Value *V) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 654 | // If we're asked to materialize a value that is an instruction, we |
| 655 | // temporarily create an alloca in the outlined function and add this |
| 656 | // to the FrameVarInfo map. When all the outlining is complete, we'll |
| 657 | // collect these into a structure, spilling non-alloca values in the |
| 658 | // parent frame as necessary, and replace these temporary allocas with |
| 659 | // GEPs referencing the frame allocation block. |
| 660 | |
| 661 | // If the value is an alloca, the mapping is direct. |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 662 | if (auto *AV = dyn_cast<AllocaInst>(V)) { |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 663 | AllocaInst *NewAlloca = dyn_cast<AllocaInst>(AV->clone()); |
| 664 | Builder.Insert(NewAlloca, AV->getName()); |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 665 | FrameVarInfo[AV].push_back(NewAlloca); |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 666 | return NewAlloca; |
| 667 | } |
| 668 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 669 | // For other types of instructions or arguments, we need an alloca based on |
| 670 | // the value's type and a load of the alloca. The alloca will be replaced |
| 671 | // by a GEP, but the load will stay. In the parent function, the value will |
| 672 | // be spilled to a location in the frame allocation block. |
| 673 | if (isa<Instruction>(V) || isa<Argument>(V)) { |
| 674 | AllocaInst *NewAlloca = |
| 675 | Builder.CreateAlloca(V->getType(), nullptr, "eh.temp.alloca"); |
Reid Kleckner | cfb9ce5 | 2015-03-05 18:26:34 +0000 | [diff] [blame] | 676 | FrameVarInfo[V].push_back(NewAlloca); |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 677 | LoadInst *NewLoad = Builder.CreateLoad(NewAlloca, V->getName() + ".reload"); |
| 678 | return NewLoad; |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 679 | } |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 680 | |
Andrew Kaylor | 72029c6 | 2015-03-03 00:41:03 +0000 | [diff] [blame] | 681 | // Don't materialize other values. |
Andrew Kaylor | 1476e6d | 2015-02-24 20:49:35 +0000 | [diff] [blame] | 682 | return nullptr; |
| 683 | } |