Exemplo n.º 1
0
llvm::Constant *
CodeGenVTables::CreateVTableInitializer(const CXXRecordDecl *RD,
                                        const VTableComponent *Components, 
                                        unsigned NumComponents,
                                const VTableLayout::VTableThunkTy *VTableThunks,
                                        unsigned NumVTableThunks) {
  SmallVector<llvm::Constant *, 64> Inits;

  llvm::Type *Int8PtrTy = CGM.Int8PtrTy;
  
  llvm::Type *PtrDiffTy = 
    CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());

  QualType ClassType = CGM.getContext().getTagDeclType(RD);
  llvm::Constant *RTTI = CGM.GetAddrOfRTTIDescriptor(ClassType);
  
  unsigned NextVTableThunkIndex = 0;
  
  llvm::Constant *PureVirtualFn = 0, *DeletedVirtualFn = 0;

  for (unsigned I = 0; I != NumComponents; ++I) {
    VTableComponent Component = Components[I];

    llvm::Constant *Init = 0;

    switch (Component.getKind()) {
    case VTableComponent::CK_VCallOffset:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getVCallOffset().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_VBaseOffset:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getVBaseOffset().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_OffsetToTop:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getOffsetToTop().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_RTTI:
      Init = llvm::ConstantExpr::getBitCast(RTTI, Int8PtrTy);
      break;
    case VTableComponent::CK_FunctionPointer:
    case VTableComponent::CK_CompleteDtorPointer:
    case VTableComponent::CK_DeletingDtorPointer: {
      GlobalDecl GD;
      
      // Get the right global decl.
      switch (Component.getKind()) {
      default:
        llvm_unreachable("Unexpected vtable component kind");
      case VTableComponent::CK_FunctionPointer:
        GD = Component.getFunctionDecl();
        break;
      case VTableComponent::CK_CompleteDtorPointer:
        GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Complete);
        break;
      case VTableComponent::CK_DeletingDtorPointer:
        GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Deleting);
        break;
      }

      if (cast<CXXMethodDecl>(GD.getDecl())->isPure()) {
        // We have a pure virtual member function.
        if (!PureVirtualFn) {
          llvm::FunctionType *Ty = 
            llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
          StringRef PureCallName = CGM.getCXXABI().GetPureVirtualCallName();
          PureVirtualFn = CGM.CreateRuntimeFunction(Ty, PureCallName);
          PureVirtualFn = llvm::ConstantExpr::getBitCast(PureVirtualFn,
                                                         CGM.Int8PtrTy);
        }
        Init = PureVirtualFn;
      } else if (cast<CXXMethodDecl>(GD.getDecl())->isDeleted()) {
        if (!DeletedVirtualFn) {
          llvm::FunctionType *Ty =
            llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
          StringRef DeletedCallName =
            CGM.getCXXABI().GetDeletedVirtualCallName();
          DeletedVirtualFn = CGM.CreateRuntimeFunction(Ty, DeletedCallName);
          DeletedVirtualFn = llvm::ConstantExpr::getBitCast(DeletedVirtualFn,
                                                         CGM.Int8PtrTy);
        }
        Init = DeletedVirtualFn;
      } else {
        // Check if we should use a thunk.
        if (NextVTableThunkIndex < NumVTableThunks &&
            VTableThunks[NextVTableThunkIndex].first == I) {
          const ThunkInfo &Thunk = VTableThunks[NextVTableThunkIndex].second;
        
          maybeEmitThunkForVTable(GD, Thunk);
          Init = CGM.GetAddrOfThunk(GD, Thunk);

          NextVTableThunkIndex++;
        } else {
          llvm::Type *Ty = CGM.getTypes().GetFunctionTypeForVTable(GD);
        
          Init = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
        }

        Init = llvm::ConstantExpr::getBitCast(Init, Int8PtrTy);
      }
      break;
    }

    case VTableComponent::CK_UnusedFunctionPointer:
      Init = llvm::ConstantExpr::getNullValue(Int8PtrTy);
      break;
    };
    
    Inits.push_back(Init);
  }
  
  llvm::ArrayType *ArrayType = llvm::ArrayType::get(Int8PtrTy, NumComponents);
  return llvm::ConstantArray::get(ArrayType, Inits);
}
Exemplo n.º 2
0
llvm::Constant *CodeGenVTables::CreateVTableInitializer(
    const CXXRecordDecl *RD, const VTableComponent *Components,
    unsigned NumComponents, const VTableLayout::VTableThunkTy *VTableThunks,
    unsigned NumVTableThunks, llvm::Constant *RTTI) {
  SmallVector<llvm::Constant *, 64> Inits;

  llvm::Type *Int8PtrTy = CGM.Int8PtrTy;
  
  llvm::Type *PtrDiffTy = 
    CGM.getTypes().ConvertType(CGM.getContext().getPointerDiffType());

  unsigned NextVTableThunkIndex = 0;

  llvm::Constant *PureVirtualFn = nullptr, *DeletedVirtualFn = nullptr;

  for (unsigned I = 0; I != NumComponents; ++I) {
    VTableComponent Component = Components[I];

    llvm::Constant *Init = nullptr;

    switch (Component.getKind()) {
    case VTableComponent::CK_VCallOffset:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getVCallOffset().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_VBaseOffset:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getVBaseOffset().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_OffsetToTop:
      Init = llvm::ConstantInt::get(PtrDiffTy, 
                                    Component.getOffsetToTop().getQuantity());
      Init = llvm::ConstantExpr::getIntToPtr(Init, Int8PtrTy);
      break;
    case VTableComponent::CK_RTTI:
      Init = llvm::ConstantExpr::getBitCast(RTTI, Int8PtrTy);
      break;
    case VTableComponent::CK_FunctionPointer:
    case VTableComponent::CK_CompleteDtorPointer:
    case VTableComponent::CK_DeletingDtorPointer: {
      GlobalDecl GD;
      
      // Get the right global decl.
      switch (Component.getKind()) {
      default:
        llvm_unreachable("Unexpected vtable component kind");
      case VTableComponent::CK_FunctionPointer:
        GD = Component.getFunctionDecl();
        break;
      case VTableComponent::CK_CompleteDtorPointer:
        GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Complete);
        break;
      case VTableComponent::CK_DeletingDtorPointer:
        GD = GlobalDecl(Component.getDestructorDecl(), Dtor_Deleting);
        break;
      }

      if (CGM.getLangOpts().CUDA) {
        // Emit NULL for methods we can't codegen on this
        // side. Otherwise we'd end up with vtable with unresolved
        // references.
        const CXXMethodDecl *MD = cast<CXXMethodDecl>(GD.getDecl());
        // OK on device side: functions w/ __device__ attribute
        // OK on host side: anything except __device__-only functions.
        bool CanEmitMethod = CGM.getLangOpts().CUDAIsDevice
                                 ? MD->hasAttr<CUDADeviceAttr>()
                                 : (MD->hasAttr<CUDAHostAttr>() ||
                                    !MD->hasAttr<CUDADeviceAttr>());
        if (!CanEmitMethod) {
          Init = llvm::ConstantExpr::getNullValue(Int8PtrTy);
          break;
        }
        // Method is acceptable, continue processing as usual.
      }

      if (cast<CXXMethodDecl>(GD.getDecl())->isPure()) {
        // We have a pure virtual member function.
        if (!PureVirtualFn) {
          llvm::FunctionType *Ty = 
            llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
          StringRef PureCallName = CGM.getCXXABI().GetPureVirtualCallName();
          PureVirtualFn = CGM.CreateRuntimeFunction(Ty, PureCallName);
          if (auto *F = dyn_cast<llvm::Function>(PureVirtualFn))
            F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
          PureVirtualFn = llvm::ConstantExpr::getBitCast(PureVirtualFn,
                                                         CGM.Int8PtrTy);
        }
        Init = PureVirtualFn;
      } else if (cast<CXXMethodDecl>(GD.getDecl())->isDeleted()) {
        if (!DeletedVirtualFn) {
          llvm::FunctionType *Ty =
            llvm::FunctionType::get(CGM.VoidTy, /*isVarArg=*/false);
          StringRef DeletedCallName =
            CGM.getCXXABI().GetDeletedVirtualCallName();
          DeletedVirtualFn = CGM.CreateRuntimeFunction(Ty, DeletedCallName);
          if (auto *F = dyn_cast<llvm::Function>(DeletedVirtualFn))
            F->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
          DeletedVirtualFn = llvm::ConstantExpr::getBitCast(DeletedVirtualFn,
                                                         CGM.Int8PtrTy);
        }
        Init = DeletedVirtualFn;
      } else {
        // Check if we should use a thunk.
        if (NextVTableThunkIndex < NumVTableThunks &&
            VTableThunks[NextVTableThunkIndex].first == I) {
          const ThunkInfo &Thunk = VTableThunks[NextVTableThunkIndex].second;
        
          maybeEmitThunkForVTable(GD, Thunk);
          Init = CGM.GetAddrOfThunk(GD, Thunk);

          NextVTableThunkIndex++;
        } else {
          llvm::Type *Ty = CGM.getTypes().GetFunctionTypeForVTable(GD);
        
          Init = CGM.GetAddrOfFunction(GD, Ty, /*ForVTable=*/true);
        }

        Init = llvm::ConstantExpr::getBitCast(Init, Int8PtrTy);
      }
      break;
    }

    case VTableComponent::CK_UnusedFunctionPointer:
      Init = llvm::ConstantExpr::getNullValue(Int8PtrTy);
      break;
    };
    
    Inits.push_back(Init);
  }
  
  llvm::ArrayType *ArrayType = llvm::ArrayType::get(Int8PtrTy, NumComponents);
  return llvm::ConstantArray::get(ArrayType, Inits);
}