| //===--- CGException.cpp - Emit LLVM Code for C++ exceptions --------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This contains code dealing with C++ exception related code generation. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/AST/StmtCXX.h" |
| |
| #include "llvm/Intrinsics.h" |
| |
| #include "CodeGenFunction.h" |
| using namespace clang; |
| using namespace CodeGen; |
| |
| static llvm::Constant *getAllocateExceptionFn(CodeGenFunction &CGF) { |
| // void *__cxa_allocate_exception(size_t thrown_size); |
| const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType()); |
| std::vector<const llvm::Type*> Args(1, SizeTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getInt8PtrTy(CGF.getLLVMContext()), |
| Args, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception"); |
| } |
| |
| static llvm::Constant *getFreeExceptionFn(CodeGenFunction &CGF) { |
| // void __cxa_free_exception(void *thrown_exception); |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); |
| std::vector<const llvm::Type*> Args(1, Int8PtrTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), |
| Args, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception"); |
| } |
| |
| static llvm::Constant *getThrowFn(CodeGenFunction &CGF) { |
| // void __cxa_throw(void *thrown_exception, std::type_info *tinfo, |
| // void (*dest) (void *)); |
| |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); |
| std::vector<const llvm::Type*> Args(3, Int8PtrTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), |
| Args, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_throw"); |
| } |
| |
| static llvm::Constant *getReThrowFn(CodeGenFunction &CGF) { |
| // void __cxa_rethrow(); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_rethrow"); |
| } |
| |
| static llvm::Constant *getBeginCatchFn(CodeGenFunction &CGF) { |
| // void* __cxa_begin_catch(); |
| |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); |
| std::vector<const llvm::Type*> Args(1, Int8PtrTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(Int8PtrTy, Args, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_begin_catch"); |
| } |
| |
| static llvm::Constant *getEndCatchFn(CodeGenFunction &CGF) { |
| // void __cxa_end_catch(); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_end_catch"); |
| } |
| |
| static llvm::Constant *getUnexpectedFn(CodeGenFunction &CGF) { |
| // void __cxa_call_unexepcted(void *thrown_exception); |
| |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); |
| std::vector<const llvm::Type*> Args(1, Int8PtrTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), |
| Args, false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected"); |
| } |
| |
| static llvm::Constant *getUnwindResumeOrRethrowFn(CodeGenFunction &CGF) { |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext()); |
| std::vector<const llvm::Type*> Args(1, Int8PtrTy); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), Args, |
| false); |
| |
| if (CGF.CGM.getLangOptions().SjLjExceptions) |
| return CGF.CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume"); |
| return CGF.CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume_or_Rethrow"); |
| } |
| |
| static llvm::Constant *getTerminateFn(CodeGenFunction &CGF) { |
| // void __terminate(); |
| |
| const llvm::FunctionType *FTy = |
| llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false); |
| |
| return CGF.CGM.CreateRuntimeFunction(FTy, "_ZSt9terminatev"); |
| } |
| |
| // Emits an exception expression into the given location. This |
| // differs from EmitAnyExprToMem only in that, if a final copy-ctor |
| // call is required, an exception within that copy ctor causes |
| // std::terminate to be invoked. |
| static void EmitAnyExprToExn(CodeGenFunction &CGF, const Expr *E, |
| llvm::Value *ExnLoc) { |
| // We want to release the allocated exception object if this |
| // expression throws. We do this by pushing an EH-only cleanup |
| // block which, furthermore, deactivates itself after the expression |
| // is complete. |
| llvm::AllocaInst *ShouldFreeVar = |
| CGF.CreateTempAlloca(llvm::Type::getInt1Ty(CGF.getLLVMContext()), |
| "should-free-exnobj.var"); |
| CGF.InitTempAlloca(ShouldFreeVar, |
| llvm::ConstantInt::getFalse(CGF.getLLVMContext())); |
| |
| // A variable holding the exception pointer. This is necessary |
| // because the throw expression does not necessarily dominate the |
| // cleanup, for example if it appears in a conditional expression. |
| llvm::AllocaInst *ExnLocVar = |
| CGF.CreateTempAlloca(ExnLoc->getType(), "exnobj.var"); |
| |
| llvm::BasicBlock *SavedInvokeDest = CGF.getInvokeDest(); |
| { |
| CodeGenFunction::EHCleanupBlock Cleanup(CGF); |
| llvm::BasicBlock *FreeBB = CGF.createBasicBlock("free-exnobj"); |
| llvm::BasicBlock *DoneBB = CGF.createBasicBlock("free-exnobj.done"); |
| |
| llvm::Value *ShouldFree = CGF.Builder.CreateLoad(ShouldFreeVar, |
| "should-free-exnobj"); |
| CGF.Builder.CreateCondBr(ShouldFree, FreeBB, DoneBB); |
| CGF.EmitBlock(FreeBB); |
| llvm::Value *ExnLocLocal = CGF.Builder.CreateLoad(ExnLocVar, "exnobj"); |
| CGF.Builder.CreateCall(getFreeExceptionFn(CGF), ExnLocLocal); |
| CGF.EmitBlock(DoneBB); |
| } |
| llvm::BasicBlock *Cleanup = CGF.getInvokeDest(); |
| |
| CGF.Builder.CreateStore(ExnLoc, ExnLocVar); |
| CGF.Builder.CreateStore(llvm::ConstantInt::getTrue(CGF.getLLVMContext()), |
| ShouldFreeVar); |
| |
| // __cxa_allocate_exception returns a void*; we need to cast this |
| // to the appropriate type for the object. |
| const llvm::Type *Ty = CGF.ConvertType(E->getType())->getPointerTo(); |
| llvm::Value *TypedExnLoc = CGF.Builder.CreateBitCast(ExnLoc, Ty); |
| |
| // FIXME: this isn't quite right! If there's a final unelided call |
| // to a copy constructor, then according to [except.terminate]p1 we |
| // must call std::terminate() if that constructor throws, because |
| // technically that copy occurs after the exception expression is |
| // evaluated but before the exception is caught. But the best way |
| // to handle that is to teach EmitAggExpr to do the final copy |
| // differently if it can't be elided. |
| CGF.EmitAnyExprToMem(E, TypedExnLoc, /*Volatile*/ false); |
| |
| CGF.Builder.CreateStore(llvm::ConstantInt::getFalse(CGF.getLLVMContext()), |
| ShouldFreeVar); |
| |
| // Pop the cleanup block if it's still the top of the cleanup stack. |
| // Otherwise, temporaries have been created and our cleanup will get |
| // properly removed in time. |
| // TODO: this is not very resilient. |
| if (CGF.getInvokeDest() == Cleanup) |
| CGF.setInvokeDest(SavedInvokeDest); |
| } |
| |
| // CopyObject - Utility to copy an object. Calls copy constructor as necessary. |
| // N is casted to the right type. |
| static void CopyObject(CodeGenFunction &CGF, QualType ObjectType, |
| bool WasPointer, bool WasPointerReference, |
| llvm::Value *E, llvm::Value *N) { |
| // Store the throw exception in the exception object. |
| if (WasPointer || !CGF.hasAggregateLLVMType(ObjectType)) { |
| llvm::Value *Value = E; |
| if (!WasPointer) |
| Value = CGF.Builder.CreateLoad(Value); |
| const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0); |
| if (WasPointerReference) { |
| llvm::Value *Tmp = CGF.CreateTempAlloca(Value->getType(), "catch.param"); |
| CGF.Builder.CreateStore(Value, Tmp); |
| Value = Tmp; |
| ValuePtrTy = Value->getType()->getPointerTo(0); |
| } |
| N = CGF.Builder.CreateBitCast(N, ValuePtrTy); |
| CGF.Builder.CreateStore(Value, N); |
| } else { |
| const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo(0); |
| const CXXRecordDecl *RD; |
| RD = cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl()); |
| llvm::Value *This = CGF.Builder.CreateBitCast(N, Ty); |
| if (RD->hasTrivialCopyConstructor()) { |
| CGF.EmitAggregateCopy(This, E, ObjectType); |
| } else if (CXXConstructorDecl *CopyCtor |
| = RD->getCopyConstructor(CGF.getContext(), 0)) { |
| llvm::Value *Src = E; |
| |
| // Stolen from EmitClassAggrMemberwiseCopy |
| llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor, |
| Ctor_Complete); |
| CallArgList CallArgs; |
| CallArgs.push_back(std::make_pair(RValue::get(This), |
| CopyCtor->getThisType(CGF.getContext()))); |
| |
| // Push the Src ptr. |
| CallArgs.push_back(std::make_pair(RValue::get(Src), |
| CopyCtor->getParamDecl(0)->getType())); |
| |
| const FunctionProtoType *FPT |
| = CopyCtor->getType()->getAs<FunctionProtoType>(); |
| CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(CallArgs, FPT), |
| Callee, ReturnValueSlot(), CallArgs, CopyCtor); |
| } else |
| llvm_unreachable("uncopyable object"); |
| } |
| } |
| |
| void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) { |
| if (!E->getSubExpr()) { |
| if (getInvokeDest()) { |
| llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); |
| Builder.CreateInvoke(getReThrowFn(*this), Cont, getInvokeDest()) |
| ->setDoesNotReturn(); |
| EmitBlock(Cont); |
| } else |
| Builder.CreateCall(getReThrowFn(*this))->setDoesNotReturn(); |
| Builder.CreateUnreachable(); |
| |
| // Clear the insertion point to indicate we are in unreachable code. |
| Builder.ClearInsertionPoint(); |
| return; |
| } |
| |
| QualType ThrowType = E->getSubExpr()->getType(); |
| |
| // Now allocate the exception object. |
| const llvm::Type *SizeTy = ConvertType(getContext().getSizeType()); |
| uint64_t TypeSize = getContext().getTypeSizeInChars(ThrowType).getQuantity(); |
| |
| llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(*this); |
| llvm::Value *ExceptionPtr = |
| Builder.CreateCall(AllocExceptionFn, |
| llvm::ConstantInt::get(SizeTy, TypeSize), |
| "exception"); |
| |
| EmitAnyExprToExn(*this, E->getSubExpr(), ExceptionPtr); |
| |
| // Now throw the exception. |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext()); |
| llvm::Constant *TypeInfo = CGM.GetAddrOfRTTIDescriptor(ThrowType); |
| |
| // The address of the destructor. If the exception type has a |
| // trivial destructor (or isn't a record), we just pass null. |
| llvm::Constant *Dtor = 0; |
| if (const RecordType *RecordTy = ThrowType->getAs<RecordType>()) { |
| CXXRecordDecl *Record = cast<CXXRecordDecl>(RecordTy->getDecl()); |
| if (!Record->hasTrivialDestructor()) { |
| CXXDestructorDecl *DtorD = Record->getDestructor(getContext()); |
| Dtor = CGM.GetAddrOfCXXDestructor(DtorD, Dtor_Complete); |
| Dtor = llvm::ConstantExpr::getBitCast(Dtor, Int8PtrTy); |
| } |
| } |
| if (!Dtor) Dtor = llvm::Constant::getNullValue(Int8PtrTy); |
| |
| if (getInvokeDest()) { |
| llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); |
| llvm::InvokeInst *ThrowCall = |
| Builder.CreateInvoke3(getThrowFn(*this), Cont, getInvokeDest(), |
| ExceptionPtr, TypeInfo, Dtor); |
| ThrowCall->setDoesNotReturn(); |
| EmitBlock(Cont); |
| } else { |
| llvm::CallInst *ThrowCall = |
| Builder.CreateCall3(getThrowFn(*this), ExceptionPtr, TypeInfo, Dtor); |
| ThrowCall->setDoesNotReturn(); |
| } |
| Builder.CreateUnreachable(); |
| |
| // Clear the insertion point to indicate we are in unreachable code. |
| Builder.ClearInsertionPoint(); |
| |
| // FIXME: For now, emit a dummy basic block because expr emitters in generally |
| // are not ready to handle emitting expressions at unreachable points. |
| EnsureInsertPoint(); |
| } |
| |
| void CodeGenFunction::EmitStartEHSpec(const Decl *D) { |
| if (!Exceptions) |
| return; |
| |
| const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D); |
| if (FD == 0) |
| return; |
| const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>(); |
| if (Proto == 0) |
| return; |
| |
| assert(!Proto->hasAnyExceptionSpec() && "function with parameter pack"); |
| |
| if (!Proto->hasExceptionSpec()) |
| return; |
| |
| llvm::Constant *Personality = |
| CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty |
| (VMContext), |
| true), |
| "__gxx_personality_v0"); |
| Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty); |
| llvm::Value *llvm_eh_exception = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_exception); |
| llvm::Value *llvm_eh_selector = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_selector); |
| const llvm::IntegerType *Int8Ty; |
| const llvm::PointerType *PtrToInt8Ty; |
| Int8Ty = llvm::Type::getInt8Ty(VMContext); |
| // C string type. Used in lots of places. |
| PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty); |
| llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty); |
| llvm::SmallVector<llvm::Value*, 8> SelectorArgs; |
| |
| llvm::BasicBlock *PrevLandingPad = getInvokeDest(); |
| llvm::BasicBlock *EHSpecHandler = createBasicBlock("ehspec.handler"); |
| llvm::BasicBlock *Match = createBasicBlock("match"); |
| llvm::BasicBlock *Unwind = 0; |
| |
| assert(PrevLandingPad == 0 && "EHSpec has invoke context"); |
| (void)PrevLandingPad; |
| |
| llvm::BasicBlock *Cont = createBasicBlock("cont"); |
| |
| EmitBranchThroughCleanup(Cont); |
| |
| // Emit the statements in the try {} block |
| setInvokeDest(EHSpecHandler); |
| |
| EmitBlock(EHSpecHandler); |
| // Exception object |
| llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc"); |
| llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow"); |
| |
| SelectorArgs.push_back(Exc); |
| SelectorArgs.push_back(Personality); |
| SelectorArgs.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), |
| Proto->getNumExceptions()+1)); |
| |
| for (unsigned i = 0; i < Proto->getNumExceptions(); ++i) { |
| QualType Ty = Proto->getExceptionType(i); |
| QualType ExceptType |
| = Ty.getNonReferenceType().getUnqualifiedType(); |
| llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType); |
| SelectorArgs.push_back(EHType); |
| } |
| if (Proto->getNumExceptions()) |
| SelectorArgs.push_back(Null); |
| |
| // Find which handler was matched. |
| llvm::Value *Selector |
| = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(), |
| SelectorArgs.end(), "selector"); |
| if (Proto->getNumExceptions()) { |
| Unwind = createBasicBlock("Unwind"); |
| |
| Builder.CreateStore(Exc, RethrowPtr); |
| Builder.CreateCondBr(Builder.CreateICmpSLT(Selector, |
| llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), |
| 0)), |
| Match, Unwind); |
| |
| EmitBlock(Match); |
| } |
| Builder.CreateCall(getUnexpectedFn(*this), Exc)->setDoesNotReturn(); |
| Builder.CreateUnreachable(); |
| |
| if (Proto->getNumExceptions()) { |
| EmitBlock(Unwind); |
| Builder.CreateCall(getUnwindResumeOrRethrowFn(*this), |
| Builder.CreateLoad(RethrowPtr)); |
| Builder.CreateUnreachable(); |
| } |
| |
| EmitBlock(Cont); |
| } |
| |
| void CodeGenFunction::EmitEndEHSpec(const Decl *D) { |
| if (!Exceptions) |
| return; |
| |
| const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D); |
| if (FD == 0) |
| return; |
| const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>(); |
| if (Proto == 0) |
| return; |
| |
| if (!Proto->hasExceptionSpec()) |
| return; |
| |
| setInvokeDest(0); |
| } |
| |
| void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) { |
| CXXTryStmtInfo Info = EnterCXXTryStmt(S); |
| EmitStmt(S.getTryBlock()); |
| ExitCXXTryStmt(S, Info); |
| } |
| |
| CodeGenFunction::CXXTryStmtInfo |
| CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S) { |
| CXXTryStmtInfo Info; |
| Info.SavedLandingPad = getInvokeDest(); |
| Info.HandlerBlock = createBasicBlock("try.handler"); |
| Info.FinallyBlock = createBasicBlock("finally"); |
| |
| PushCleanupBlock(Info.FinallyBlock); |
| setInvokeDest(Info.HandlerBlock); |
| |
| return Info; |
| } |
| |
| void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, |
| CXXTryStmtInfo TryInfo) { |
| // Pointer to the personality function |
| llvm::Constant *Personality = |
| CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty |
| (VMContext), |
| true), |
| "__gxx_personality_v0"); |
| Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty); |
| llvm::Value *llvm_eh_exception = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_exception); |
| llvm::Value *llvm_eh_selector = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_selector); |
| |
| llvm::BasicBlock *PrevLandingPad = TryInfo.SavedLandingPad; |
| llvm::BasicBlock *TryHandler = TryInfo.HandlerBlock; |
| llvm::BasicBlock *FinallyBlock = TryInfo.FinallyBlock; |
| llvm::BasicBlock *FinallyRethrow = createBasicBlock("finally.throw"); |
| llvm::BasicBlock *FinallyEnd = createBasicBlock("finally.end"); |
| |
| // Jump to end if there is no exception |
| EmitBranchThroughCleanup(FinallyEnd); |
| |
| llvm::BasicBlock *TerminateHandler = getTerminateHandler(); |
| |
| // Emit the handlers |
| EmitBlock(TryHandler); |
| |
| const llvm::IntegerType *Int8Ty; |
| const llvm::PointerType *PtrToInt8Ty; |
| Int8Ty = llvm::Type::getInt8Ty(VMContext); |
| // C string type. Used in lots of places. |
| PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty); |
| llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty); |
| llvm::SmallVector<llvm::Value*, 8> SelectorArgs; |
| llvm::Value *llvm_eh_typeid_for = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for); |
| // Exception object |
| llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc"); |
| llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow"); |
| |
| SelectorArgs.push_back(Exc); |
| SelectorArgs.push_back(Personality); |
| |
| bool HasCatchAll = false; |
| for (unsigned i = 0; i<S.getNumHandlers(); ++i) { |
| const CXXCatchStmt *C = S.getHandler(i); |
| VarDecl *CatchParam = C->getExceptionDecl(); |
| if (CatchParam) { |
| // C++ [except.handle]p3 indicates that top-level cv-qualifiers |
| // are ignored. |
| QualType CaughtType = C->getCaughtType().getNonReferenceType(); |
| llvm::Value *EHTypeInfo |
| = CGM.GetAddrOfRTTIDescriptor(CaughtType.getUnqualifiedType()); |
| SelectorArgs.push_back(EHTypeInfo); |
| } else { |
| // null indicates catch all |
| SelectorArgs.push_back(Null); |
| HasCatchAll = true; |
| } |
| } |
| |
| // We use a cleanup unless there was already a catch all. |
| if (!HasCatchAll) { |
| SelectorArgs.push_back(Null); |
| } |
| |
| // Find which handler was matched. |
| llvm::Value *Selector |
| = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(), |
| SelectorArgs.end(), "selector"); |
| for (unsigned i = 0; i<S.getNumHandlers(); ++i) { |
| const CXXCatchStmt *C = S.getHandler(i); |
| VarDecl *CatchParam = C->getExceptionDecl(); |
| Stmt *CatchBody = C->getHandlerBlock(); |
| |
| llvm::BasicBlock *Next = 0; |
| |
| if (SelectorArgs[i+2] != Null) { |
| llvm::BasicBlock *Match = createBasicBlock("match"); |
| Next = createBasicBlock("catch.next"); |
| const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext()); |
| llvm::Value *Id |
| = Builder.CreateCall(llvm_eh_typeid_for, |
| Builder.CreateBitCast(SelectorArgs[i+2], |
| Int8PtrTy)); |
| Builder.CreateCondBr(Builder.CreateICmpEQ(Selector, Id), |
| Match, Next); |
| EmitBlock(Match); |
| } |
| |
| llvm::BasicBlock *MatchEnd = createBasicBlock("match.end"); |
| llvm::BasicBlock *MatchHandler = createBasicBlock("match.handler"); |
| |
| PushCleanupBlock(MatchEnd); |
| setInvokeDest(MatchHandler); |
| |
| llvm::Value *ExcObject = Builder.CreateCall(getBeginCatchFn(*this), Exc); |
| |
| { |
| CleanupScope CatchScope(*this); |
| // Bind the catch parameter if it exists. |
| if (CatchParam) { |
| QualType CatchType = CatchParam->getType().getNonReferenceType(); |
| setInvokeDest(TerminateHandler); |
| bool WasPointer = true; |
| bool WasPointerReference = false; |
| CatchType = CGM.getContext().getCanonicalType(CatchType); |
| if (CatchType.getTypePtr()->isPointerType()) { |
| if (isa<ReferenceType>(CatchParam->getType())) |
| WasPointerReference = true; |
| } else { |
| if (!isa<ReferenceType>(CatchParam->getType())) |
| WasPointer = false; |
| CatchType = getContext().getPointerType(CatchType); |
| } |
| ExcObject = Builder.CreateBitCast(ExcObject, ConvertType(CatchType)); |
| EmitLocalBlockVarDecl(*CatchParam); |
| // FIXME: we need to do this sooner so that the EH region for the |
| // cleanup doesn't start until after the ctor completes, use a decl |
| // init? |
| CopyObject(*this, CatchParam->getType().getNonReferenceType(), |
| WasPointer, WasPointerReference, ExcObject, |
| GetAddrOfLocalVar(CatchParam)); |
| setInvokeDest(MatchHandler); |
| } |
| |
| EmitStmt(CatchBody); |
| } |
| |
| EmitBranchThroughCleanup(FinallyEnd); |
| |
| EmitBlock(MatchHandler); |
| |
| llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc"); |
| // We are required to emit this call to satisfy LLVM, even |
| // though we don't use the result. |
| llvm::Value *Args[] = { |
| Exc, Personality, |
| llvm::ConstantInt::getNullValue(llvm::Type::getInt32Ty(VMContext)) |
| }; |
| Builder.CreateCall(llvm_eh_selector, &Args[0], llvm::array_endof(Args)); |
| Builder.CreateStore(Exc, RethrowPtr); |
| EmitBranchThroughCleanup(FinallyRethrow); |
| |
| CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock(); |
| |
| EmitBlock(MatchEnd); |
| |
| llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); |
| Builder.CreateInvoke(getEndCatchFn(*this), |
| Cont, TerminateHandler, |
| &Args[0], &Args[0]); |
| EmitBlock(Cont); |
| if (Info.SwitchBlock) |
| EmitBlock(Info.SwitchBlock); |
| if (Info.EndBlock) |
| EmitBlock(Info.EndBlock); |
| |
| Exc = Builder.CreateCall(llvm_eh_exception, "exc"); |
| Builder.CreateStore(Exc, RethrowPtr); |
| EmitBranchThroughCleanup(FinallyRethrow); |
| |
| if (Next) |
| EmitBlock(Next); |
| } |
| if (!HasCatchAll) { |
| Builder.CreateStore(Exc, RethrowPtr); |
| EmitBranchThroughCleanup(FinallyRethrow); |
| } |
| |
| CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock(); |
| |
| setInvokeDest(PrevLandingPad); |
| |
| EmitBlock(FinallyBlock); |
| |
| if (Info.SwitchBlock) |
| EmitBlock(Info.SwitchBlock); |
| if (Info.EndBlock) |
| EmitBlock(Info.EndBlock); |
| |
| // Branch around the rethrow code. |
| EmitBranch(FinallyEnd); |
| |
| EmitBlock(FinallyRethrow); |
| // FIXME: Eventually we can chain the handlers together and just do a call |
| // here. |
| if (getInvokeDest()) { |
| llvm::BasicBlock *Cont = createBasicBlock("invoke.cont"); |
| Builder.CreateInvoke(getUnwindResumeOrRethrowFn(*this), Cont, |
| getInvokeDest(), |
| Builder.CreateLoad(RethrowPtr)); |
| EmitBlock(Cont); |
| } else |
| Builder.CreateCall(getUnwindResumeOrRethrowFn(*this), |
| Builder.CreateLoad(RethrowPtr)); |
| |
| Builder.CreateUnreachable(); |
| |
| EmitBlock(FinallyEnd); |
| } |
| |
| CodeGenFunction::EHCleanupBlock::~EHCleanupBlock() { |
| CGF.setInvokeDest(PreviousInvokeDest); |
| |
| llvm::BasicBlock *EndOfCleanup = CGF.Builder.GetInsertBlock(); |
| |
| // Jump to the beginning of the cleanup. |
| CGF.Builder.SetInsertPoint(CleanupHandler, CleanupHandler->begin()); |
| |
| // The libstdc++ personality function. |
| // TODO: generalize to work with other libraries. |
| llvm::Constant *Personality = |
| CGF.CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty |
| (CGF.VMContext), |
| true), |
| "__gxx_personality_v0"); |
| Personality = llvm::ConstantExpr::getBitCast(Personality, CGF.PtrToInt8Ty); |
| |
| // %exception = call i8* @llvm.eh.exception() |
| // Magic intrinsic which tells gives us a handle to the caught |
| // exception. |
| llvm::Value *llvm_eh_exception = |
| CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_exception); |
| llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc"); |
| |
| llvm::Constant *Null = llvm::ConstantPointerNull::get(CGF.PtrToInt8Ty); |
| |
| // %ignored = call i32 @llvm.eh.selector(i8* %exception, |
| // i8* @__gxx_personality_v0, |
| // i8* null) |
| // Magic intrinsic which tells LLVM that this invoke landing pad is |
| // just a cleanup block. |
| llvm::Value *Args[] = { Exc, Personality, Null }; |
| llvm::Value *llvm_eh_selector = |
| CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_selector); |
| CGF.Builder.CreateCall(llvm_eh_selector, &Args[0], llvm::array_endof(Args)); |
| |
| // And then we fall through into the code that the user put there. |
| // Jump back to the end of the cleanup. |
| CGF.Builder.SetInsertPoint(EndOfCleanup); |
| |
| // Rethrow the exception. |
| if (CGF.getInvokeDest()) { |
| llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont"); |
| CGF.Builder.CreateInvoke(getUnwindResumeOrRethrowFn(CGF), Cont, |
| CGF.getInvokeDest(), Exc); |
| CGF.EmitBlock(Cont); |
| } else |
| CGF.Builder.CreateCall(getUnwindResumeOrRethrowFn(CGF), Exc); |
| CGF.Builder.CreateUnreachable(); |
| |
| // Resume inserting where we started, but put the new cleanup |
| // handler in place. |
| CGF.Builder.SetInsertPoint(PreviousInsertionBlock); |
| if (CGF.Exceptions) |
| CGF.setInvokeDest(CleanupHandler); |
| } |
| |
| llvm::BasicBlock *CodeGenFunction::getTerminateHandler() { |
| if (TerminateHandler) |
| return TerminateHandler; |
| |
| // We don't want to change anything at the current location, so |
| // save it aside and clear the insert point. |
| llvm::BasicBlock *SavedInsertBlock = Builder.GetInsertBlock(); |
| llvm::BasicBlock::iterator SavedInsertPoint = Builder.GetInsertPoint(); |
| Builder.ClearInsertionPoint(); |
| |
| llvm::Constant *Personality = |
| CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty |
| (VMContext), |
| true), |
| "__gxx_personality_v0"); |
| Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty); |
| llvm::Value *llvm_eh_exception = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_exception); |
| llvm::Value *llvm_eh_selector = |
| CGM.getIntrinsic(llvm::Intrinsic::eh_selector); |
| |
| // Set up terminate handler |
| TerminateHandler = createBasicBlock("terminate.handler"); |
| EmitBlock(TerminateHandler); |
| llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc"); |
| // We are required to emit this call to satisfy LLVM, even |
| // though we don't use the result. |
| llvm::Value *Args[] = { |
| Exc, Personality, |
| llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext), 1) |
| }; |
| Builder.CreateCall(llvm_eh_selector, &Args[0], llvm::array_endof(Args)); |
| llvm::CallInst *TerminateCall = |
| Builder.CreateCall(getTerminateFn(*this)); |
| TerminateCall->setDoesNotReturn(); |
| TerminateCall->setDoesNotThrow(); |
| Builder.CreateUnreachable(); |
| |
| // Restore the saved insertion state. |
| Builder.SetInsertPoint(SavedInsertBlock, SavedInsertPoint); |
| |
| return TerminateHandler; |
| } |