text: //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
  //
  //                     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 code generation of C++ expressions
  //
  //===----------------------------------------------------------------------===//
  
  #include "CodeGenFunction.h"
  #include "CGCUDARuntime.h"
  #include "CGHLSLRuntime.h"     // HLSL Change
  #include "CGCXXABI.h"
  #include "CGDebugInfo.h"
  #include "CGObjCRuntime.h"
  #include "clang/CodeGen/CGFunctionInfo.h"
  #include "clang/Frontend/CodeGenOptions.h"
  #include "llvm/IR/CallSite.h"
  #include "llvm/IR/Intrinsics.h"
  
  using namespace clang;
  using namespace CodeGen;
  
  static RequiredArgs commonEmitCXXMemberOrOperatorCall(
      CodeGenFunction &CGF, const CXXMethodDecl *MD, llvm::Value *Callee,
      ReturnValueSlot ReturnValue, llvm::Value *This, llvm::Value *ImplicitParam,
      QualType ImplicitParamTy, const CallExpr *CE, CallArgList &Args, 
      ArrayRef<const Stmt *> argList// HLSL Change  - use updated argList for out parameter.
      ) {
    assert(CE == nullptr || isa<CXXMemberCallExpr>(CE) ||
           isa<CXXOperatorCallExpr>(CE));
    assert(MD->isInstance() &&
           "Trying to emit a member or operator call expr on a static method!");
  
    // C++11 [class.mfct.non-static]p2:
    //   If a non-static member function of a class X is called for an object that
    //   is not of type X, or of a type derived from X, the behavior is undefined.
    SourceLocation CallLoc;
    if (CE)
      CallLoc = CE->getExprLoc();
    CGF.EmitTypeCheck(
        isa<CXXConstructorDecl>(MD) ? CodeGenFunction::TCK_ConstructorCall
                                    : CodeGenFunction::TCK_MemberCall,
        CallLoc, This, CGF.getContext().getRecordType(MD->getParent()));
  
    // Push the this ptr.
    Args.add(RValue::get(This), MD->getThisType(CGF.getContext()));
  
    // If there is an implicit parameter (e.g. VTT), emit it.
    if (ImplicitParam) {
      Args.add(RValue::get(ImplicitParam), ImplicitParamTy);
    }
  
    const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
    RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, Args.size());
  
    // And the rest of the call args.
    if (CE) {
      // Special case: skip first argument of CXXOperatorCall (it is "this").
      unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
      CGF.EmitCallArgs(Args, FPT, 
          argList.begin() + ArgsToSkip, // HLSL Change  - use updated argList for out parameter.
          argList.end(),                // HLSL Change  - use updated argList for out parameter.
                       CE->getDirectCallee());
    } else {
      assert(
          FPT->getNumParams() == 0 &&
          "No CallExpr specified for function with non-zero number of arguments");
    }
    return required;
  }
  
  RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
      const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue,
      llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
      const CallExpr *CE) {
    const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
    CallArgList Args;
  
    // HLSL Change Begins
    llvm::SmallVector<LValue, 8> castArgList;
    // The argList of the CallExpr, may be update for out parameter
    llvm::SmallVector<const Stmt *, 8> argList(CE->arg_begin(), CE->arg_end());
    // out param conversion
    CodeGenFunction::HLSLOutParamScope OutParamScope(*this);
    auto MapTemp = [&](const VarDecl *LocalVD, llvm::Value *TmpArg) {
        OutParamScope.addTemp(LocalVD, TmpArg);
    };
    if (getLangOpts().HLSL) {
      if (const FunctionDecl *FD = CE->getDirectCallee())
        CGM.getHLSLRuntime().EmitHLSLOutParamConversionInit(*this, FD, CE,
                                                            castArgList, argList, MapTemp);
    }
    // HLSL Change Ends
  
    RequiredArgs required = commonEmitCXXMemberOrOperatorCall(
        *this, MD, Callee, ReturnValue, This, ImplicitParam, ImplicitParamTy, CE,
        Args, argList); // HLSL Change - use updated argList.
    RValue CallVal = EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
                    Callee, ReturnValue, Args, MD);
    // HLSL Change Begins
    // out param conversion
    // conversion and copy back after the call
    if (getLangOpts().HLSL)
      CGM.getHLSLRuntime().EmitHLSLOutParamConversionCopyBack(*this, castArgList);
    // HLSL Change Ends
    return CallVal;
  }
  
  RValue CodeGenFunction::EmitCXXStructorCall(
      const CXXMethodDecl *MD, llvm::Value *Callee, ReturnValueSlot ReturnValue,
      llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
      const CallExpr *CE, StructorType Type) {
    CallArgList Args;
    // HLSL Change Begins
    llvm::SmallVector<LValue, 8> castArgList;
    // The argList of the CallExpr, may be update for out parameter
    llvm::SmallVector<const Stmt *, 8> argList(CE->arg_begin(), CE->arg_end());
    // out param conversion
    CodeGenFunction::HLSLOutParamScope OutParamScope(*this);
    auto MapTemp = [&](const VarDecl *LocalVD, llvm::Value *TmpArg) {
        OutParamScope.addTemp(LocalVD, TmpArg);
    };
    if (getLangOpts().HLSL) {
      if (const FunctionDecl *FD = CE->getDirectCallee())
        CGM.getHLSLRuntime().EmitHLSLOutParamConversionInit(*this, FD, CE,
                                                            castArgList, argList, MapTemp);
    }
    // HLSL Change Ends
    commonEmitCXXMemberOrOperatorCall(*this, MD, Callee, ReturnValue, This,
                                      ImplicitParam, ImplicitParamTy, CE, Args,
        argList); // HLSL Change - use updated argList.
    RValue CallVal = EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(MD, Type),
                    Callee, ReturnValue, Args, MD);
    // HLSL Change Begins
    // out param conversion
    // conversion and copy back after the call
    if (getLangOpts().HLSL)
      CGM.getHLSLRuntime().EmitHLSLOutParamConversionCopyBack(*this, castArgList);
    // HLSL Change Ends
    return CallVal;
  }
  
  static CXXRecordDecl *getCXXRecord(const Expr *E) {
    QualType T = E->getType();
    if (const PointerType *PTy = T->getAs<PointerType>())
      T = PTy->getPointeeType();
    const RecordType *Ty = T->castAs<RecordType>();
    return cast<CXXRecordDecl>(Ty->getDecl());
  }
  
  // Note: This function also emit constructor calls to support a MSVC
  // extensions allowing explicit constructor function call.
  RValue CodeGenFunction::EmitCXXMemberCallExpr(const CXXMemberCallExpr *CE,
                                                ReturnValueSlot ReturnValue) {
    const Expr *callee = CE->getCallee()->IgnoreParens();
  
    if (isa<BinaryOperator>(callee))
      return EmitCXXMemberPointerCallExpr(CE, ReturnValue);
  
    const MemberExpr *ME = cast<MemberExpr>(callee);
    const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
  
    if (MD->isStatic()) {
      // The method is static, emit it as we would a regular call.
      llvm::Value *Callee = CGM.GetAddrOfFunction(MD);
      return EmitCall(getContext().getPointerType(MD->getType()), Callee, CE,
                      ReturnValue);
    }
  
    bool HasQualifier = ME->hasQualifier();
    NestedNameSpecifier *Qualifier = HasQualifier ? ME->getQualifier() : nullptr;
    bool IsArrow = ME->isArrow();
    const Expr *Base = ME->getBase();
  
    return EmitCXXMemberOrOperatorMemberCallExpr(
        CE, MD, ReturnValue, HasQualifier, Qualifier, IsArrow, Base);
  }
  
  RValue CodeGenFunction::EmitCXXMemberOrOperatorMemberCallExpr(
      const CallExpr *CE, const CXXMethodDecl *MD, ReturnValueSlot ReturnValue,
      bool HasQualifier, NestedNameSpecifier *Qualifier, bool IsArrow,
      const Expr *Base) {
    assert(isa<CXXMemberCallExpr>(CE) || isa<CXXOperatorCallExpr>(CE));
  
    // HLSL Change Begins
    if (hlsl::IsHLSLMatType(Base->getType())) {
      if (const CXXOperatorCallExpr *opCall = dyn_cast<CXXOperatorCallExpr>(CE)) {
        assert(opCall->getOperator() == OverloadedOperatorKind::OO_Subscript &&
               "must be subscript");
  
        llvm::Value *This = nullptr;
        if (Base->getValueKind() != ExprValueKind::VK_RValue) {
          This = EmitLValue(Base).getAddress();
        } else {
          llvm::Value *Val = EmitScalarExpr(Base);
          This = CreateTempAlloca(Val->getType());
          CGM.getHLSLRuntime().EmitHLSLMatrixStore(*this, Val, This, Base->getType());
        }
  
        llvm::Value *Idx = EmitScalarExpr(CE->getArg(1));
        llvm::Type *RetTy =
            ConvertType(getContext().getLValueReferenceType(CE->getType()));
        llvm::Value *matSub = CGM.getHLSLRuntime().EmitHLSLMatrixSubscript(
            *this, RetTy, This, Idx, Base->getType());
        return RValue::get(matSub);
      }
    }
    if (hlsl::IsHLSLVecType(Base->getType())) {
      if (const CXXOperatorCallExpr *opCall = dyn_cast<CXXOperatorCallExpr>(CE)) {
        assert(opCall->getOperator() == OverloadedOperatorKind::OO_Subscript &&
               "must be subscript");
  
        llvm::Value *This = nullptr;
        if (Base->getValueKind() != ExprValueKind::VK_RValue) {
          LValue LV = EmitLValue(Base);
          if (LV.isSimple()) {
            This = LV.getAddress();
            if (isa<ExtMatrixElementExpr>(Base)) {
              llvm::Value *Val = Builder.CreateLoad(This);
              This = CreateTempAlloca(Val->getType());
              Builder.CreateStore(Val, This);
            }
          } else {
            assert(LV.isExtVectorElt() && "must be ext vector here");
            This = LV.getExtVectorAddr();
            llvm::Constant *Elts = LV.getExtVectorElts();
            llvm::Type *Ty = ConvertType(LV.getType());
  
            llvm::Constant *zero = Builder.getInt32(0);
            llvm::Value *TmpThis = CreateTempAlloca(Ty);
            for (unsigned i = 0; i < Ty->getVectorNumElements(); i++) {
              llvm::Value *EltIdx = Elts->getAggregateElement(i);
              llvm::Value *EltGEP = Builder.CreateGEP(This, {zero, EltIdx});
              llvm::Value *TmpEltGEP =
                  Builder.CreateGEP(TmpThis, {zero, Builder.getInt32(i)});
              llvm::Value *Elt = Builder.CreateLoad(EltGEP);
              Builder.CreateStore(Elt, TmpEltGEP);
            }
            This = TmpThis;
          }
        } else {
          llvm::Value *Val = EmitScalarExpr(Base);
          This = CreateTempAlloca(Val->getType());
          Builder.CreateStore(Val, This);
        }
        bool isBool = false;
        if (llvm::IntegerType *IT =
                dyn_cast<llvm::IntegerType>(This->getType()
                                                ->getPointerElementType()
                                                ->getVectorElementType())) {
          if (IT->getBitWidth() == 1) {
            isBool = true;
          }
        }
  
        llvm::Value *Idx = EmitScalarExpr(CE->getArg(1));
        llvm::Constant *zero = llvm::ConstantInt::get(Idx->getType(), 0);
        llvm::Value *Elt = Builder.CreateGEP(This, {zero, Idx});
  
        if (isBool) {
          // bool pointer is not i1 *.
          llvm::Type *BoolTy = llvm::IntegerType::get(
              getLLVMContext(), getContext().getTypeSize(CE->getType()));
          Elt = Builder.CreateBitCast(
              Elt, llvm::PointerType::get(
                        BoolTy, Elt->getType()->getPointerAddressSpace()));
        }
  
        return RValue::get(Elt);
      }
    }
    if (hlsl::IsHLSLOutputPatchType(Base->getType()) ||
        hlsl::IsHLSLInputPatchType(Base->getType())) {
      if (const CXXOperatorCallExpr *opCall = dyn_cast<CXXOperatorCallExpr>(CE)) {
        assert(opCall->getOperator() == OverloadedOperatorKind::OO_Subscript &&
               "must be subscript");
        llvm::Value *This = EmitLValue(Base).getAddress();
        llvm::Value *Idx = EmitScalarExpr(CE->getArg(1));
        llvm::Constant *zero = llvm::ConstantInt::get(Idx->getType(), 0);
        llvm::Value *Elt = Builder.CreateGEP(This, { zero, Idx });
        return RValue::get(Elt);
      }
    }
    // HLSL Change Ends
  
    // Compute the object pointer.
    bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
  
    const CXXMethodDecl *DevirtualizedMethod = nullptr;
    if (CanUseVirtualCall && CanDevirtualizeMemberFunctionCall(Base, MD)) {
      const CXXRecordDecl *BestDynamicDecl = Base->getBestDynamicClassType();
      DevirtualizedMethod = MD->getCorrespondingMethodInClass(BestDynamicDecl);
      assert(DevirtualizedMethod);
      const CXXRecordDecl *DevirtualizedClass = DevirtualizedMethod->getParent();
      const Expr *Inner = Base->ignoreParenBaseCasts();
      if (DevirtualizedMethod->getReturnType().getCanonicalType() !=
          MD->getReturnType().getCanonicalType())
        // If the return types are not the same, this might be a case where more
        // code needs to run to compensate for it. For example, the derived
        // method might return a type that inherits form from the return
        // type of MD and has a prefix.
        // For now we just avoid devirtualizing these covariant cases.
        DevirtualizedMethod = nullptr;
      else if (getCXXRecord(Inner) == DevirtualizedClass)
        // If the class of the Inner expression is where the dynamic method
        // is defined, build the this pointer from it.
        Base = Inner;
      else if (getCXXRecord(Base) != DevirtualizedClass) {
        // If the method is defined in a class that is not the best dynamic
        // one or the one of the full expression, we would have to build
        // a derived-to-base cast to compute the correct this pointer, but
        // we don't have support for that yet, so do a virtual call.
        DevirtualizedMethod = nullptr;
      }
    }
  
    llvm::Value *This;
    if (IsArrow)
      This = EmitScalarExpr(Base);
    else
      This = EmitLValue(Base).getAddress();
  
  
    if (MD->isTrivial() || (MD->isDefaulted() && MD->getParent()->isUnion())) {
      if (isa<CXXDestructorDecl>(MD)) return RValue::get(nullptr);
      if (isa<CXXConstructorDecl>(MD) && 
          cast<CXXConstructorDecl>(MD)->isDefaultConstructor())
        return RValue::get(nullptr);
  
      if (!MD->getParent()->mayInsertExtraPadding()) {
        if (MD->isCopyAssignmentOperator() || MD->isMoveAssignmentOperator()) {
          // We don't like to generate the trivial copy/move assignment operator
          // when it isn't necessary; just produce the proper effect here.
          // Special case: skip first argument of CXXOperatorCall (it is "this").
          unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
          llvm::Value *RHS =
              EmitLValue(*(CE->arg_begin() + ArgsToSkip)).getAddress();
          EmitAggregateAssign(This, RHS, CE->getType());
          return RValue::get(This);
        }
  
        if (isa<CXXConstructorDecl>(MD) &&
            cast<CXXConstructorDecl>(MD)->isCopyOrMoveConstructor()) {
          // Trivial move and copy ctor are the same.
          assert(CE->getNumArgs() == 1 && "unexpected argcount for trivial ctor");
          llvm::Value *RHS = EmitLValue(*CE->arg_begin()).getAddress();
          EmitAggregateCopy(This, RHS, CE->arg_begin()->getType());
          return RValue::get(This);
        }
        llvm_unreachable("unknown trivial member function");
      }
    }
  
    // Compute the function type we're calling.
    const CXXMethodDecl *CalleeDecl =
        DevirtualizedMethod ? DevirtualizedMethod : MD;
    const CGFunctionInfo *FInfo = nullptr;
    if (const auto *Dtor = dyn_cast<CXXDestructorDecl>(CalleeDecl))
      FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
          Dtor, StructorType::Complete);
    else if (const auto *Ctor = dyn_cast<CXXConstructorDecl>(CalleeDecl))
      FInfo = &CGM.getTypes().arrangeCXXStructorDeclaration(
          Ctor, StructorType::Complete);
    else
      FInfo = &CGM.getTypes().arrangeCXXMethodDeclaration(CalleeDecl);
  
    llvm::FunctionType *Ty = CGM.getTypes().GetFunctionType(*FInfo);
  
    // C++ [class.virtual]p12:
    //   Explicit qualification with the scope operator (5.1) suppresses the
    //   virtual call mechanism.
    //
    // We also don't emit a virtual call if the base expression has a record type
    // because then we know what the type is.
    bool UseVirtualCall = CanUseVirtualCall && !DevirtualizedMethod;
    llvm::Value *Callee;
  
    if (const CXXDestructorDecl *Dtor = dyn_cast<CXXDestructorDecl>(MD)) {
      assert(CE->arg_begin() == CE->arg_end() &&
             "Destructor shouldn't have explicit parameters");
      assert(ReturnValue.isNull() && "Destructor shouldn't have return value");
      if (UseVirtualCall) {
        CGM.getCXXABI().EmitVirtualDestructorCall(
            *this, Dtor, Dtor_Complete, This, cast<CXXMemberCallExpr>(CE));
      } else {
        if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
          Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
        else if (!DevirtualizedMethod)
          Callee =
              CGM.getAddrOfCXXStructor(Dtor, StructorType::Complete, FInfo, Ty);
        else {
          const CXXDestructorDecl *DDtor =
            cast<CXXDestructorDecl>(DevirtualizedMethod);
          Callee = CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty);
        }
        EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This,
                                    /*ImplicitParam=*/nullptr, QualType(), CE);
      }
      return RValue::get(nullptr);
    }
    
    if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
      Callee = CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty);
    } else if (UseVirtualCall) {
      Callee = CGM.getCXXABI().getVirtualFunctionPointer(*this, MD, This, Ty,
                                                         CE->getLocStart());
    } else {
      if (SanOpts.has(SanitizerKind::CFINVCall) &&
          MD->getParent()->isDynamicClass()) {
        llvm::Value *VTable = GetVTablePtr(This, Int8PtrTy);
        EmitVTablePtrCheckForCall(MD, VTable, CFITCK_NVCall, CE->getLocStart());
      }
  
      if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
        Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
      else if (!DevirtualizedMethod)
        Callee = CGM.GetAddrOfFunction(MD, Ty);
      else {
        Callee = CGM.GetAddrOfFunction(DevirtualizedMethod, Ty);
      }
    }
  
    if (MD->isVirtual()) {
      This = CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
          *this, MD, This, UseVirtualCall);
    }
  
    return EmitCXXMemberOrOperatorCall(MD, Callee, ReturnValue, This,
                                       /*ImplicitParam=*/nullptr, QualType(), CE);
  }
  
  RValue
  CodeGenFunction::EmitCXXMemberPointerCallExpr(const CXXMemberCallExpr *E,
                                                ReturnValueSlot ReturnValue) {
    const BinaryOperator *BO =
        cast<BinaryOperator>(E->getCallee()->IgnoreParens());
    const Expr *BaseExpr = BO->getLHS();
    const Expr *MemFnExpr = BO->getRHS();
    
    const MemberPointerType *MPT = 
      MemFnExpr->getType()->castAs<MemberPointerType>();
  
    const FunctionProtoType *FPT = 
      MPT->getPointeeType()->castAs<FunctionProtoType>();
    const CXXRecordDecl *RD = 
      cast<CXXRecordDecl>(MPT->getClass()->getAs<RecordType>()->getDecl());
  
    // Get the member function pointer.
    llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
  
    // Emit the 'this' pointer.
    llvm::Value *This;
    
    if (BO->getOpcode() == BO_PtrMemI)
      This = EmitScalarExpr(BaseExpr);
    else 
      This = EmitLValue(BaseExpr).getAddress();
  
    EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This,
                  QualType(MPT->getClass(), 0));
  
    // Ask the ABI to load the callee.  Note that This is modified.
    llvm::Value *Callee =
      CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This, MemFnPtr, MPT);
    
    CallArgList Args;
  
    QualType ThisType = 
      getContext().getPointerType(getContext().getTagDeclType(RD));
  
    // Push the this ptr.
    Args.add(RValue::get(This), ThisType);
  
    RequiredArgs required = RequiredArgs::forPrototypePlus(FPT, 1);
    
    // And the rest of the call args
    EmitCallArgs(Args, FPT, E->arg_begin(), E->arg_end(), E->getDirectCallee());
    return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required),
                    Callee, ReturnValue, Args);
  }
  
  RValue
  CodeGenFunction::EmitCXXOperatorMemberCallExpr(const CXXOperatorCallExpr *E,
                                                 const CXXMethodDecl *MD,
                                                 ReturnValueSlot ReturnValue) {
    assert(MD->isInstance() &&
           "Trying to emit a member call expr on a static method!");
    return EmitCXXMemberOrOperatorMemberCallExpr(
        E, MD, ReturnValue, /*HasQualifier=*/false, /*Qualifier=*/nullptr,
        /*IsArrow=*/false, E->getArg(0));
  }
  
  RValue CodeGenFunction::EmitCUDAKernelCallExpr(const CUDAKernelCallExpr *E,
                                                 ReturnValueSlot ReturnValue) {
    return CGM.getCUDARuntime().EmitCUDAKernelCallExpr(*this, E, ReturnValue);
  }
  
  // HLSL Change Begins
  RValue CodeGenFunction::EmitHLSLBuiltinCallExpr(const FunctionDecl *FD,
                                                  const CallExpr *E,
                                                  ReturnValueSlot ReturnValue) {
    return CGM.getHLSLRuntime().EmitHLSLBuiltinCallExpr(*this, FD, E,
                                                        ReturnValue);
  }
  // HLSL Change Ends
  
  static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
                                              llvm::Value *DestPtr,
                                              const CXXRecordDecl *Base) {
    if (Base->isEmpty())
      return;
  
    DestPtr = CGF.EmitCastToVoidPtr(DestPtr);
  
    const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
    CharUnits Size = Layout.getNonVirtualSize();
    CharUnits Align = Layout.getNonVirtualAlignment();
  
    llvm::Value *SizeVal = CGF.CGM.getSize(Size);
  
    // If the type contains a pointer to data member we can't memset it to zero.
    // Instead, create a null constant and copy it to the destination.
    // TODO: there are other patterns besides zero that we can usefully memset,
    // like -1, which happens to be the pattern used by member-pointers.
    // TODO: isZeroInitializable can be over-conservative in the case where a
    // virtual base contains a member pointer.
    if (!CGF.CGM.getTypes().isZeroInitializable(Base)) {
      llvm::Constant *NullConstant = CGF.CGM.EmitNullConstantForBase(Base);
  
      llvm::GlobalVariable *NullVariable = 
        new llvm::GlobalVariable(CGF.CGM.getModule(), NullConstant->getType(),
                                 /*isConstant=*/true, 
                                 llvm::GlobalVariable::PrivateLinkage,
                                 NullConstant, Twine());
      NullVariable->setAlignment(Align.getQuantity());
      llvm::Value *SrcPtr = CGF.EmitCastToVoidPtr(NullVariable);
  
      // Get and call the appropriate llvm.memcpy overload.
      CGF.Builder.CreateMemCpy(DestPtr, SrcPtr, SizeVal, Align.getQuantity());
      return;
    } 
    
    // Otherwise, just memset the whole thing to zero.  This is legal
    // because in LLVM, all default initializers (other than the ones we just
    // handled above) are guaranteed to have a bit pattern of all zeros.
    CGF.Builder.CreateMemSet(DestPtr, CGF.Builder.getInt8(0), SizeVal,
                             Align.getQuantity());
  }
  
  void
  CodeGenFunction::EmitCXXConstructExpr(const CXXConstructExpr *E,
                                        AggValueSlot Dest) {
    assert(!Dest.isIgnored() && "Must have a destination!");
    const CXXConstructorDecl *CD = E->getConstructor();
    
    // If we require zero initialization before (or instead of) calling the
    // constructor, as can be the case with a non-user-provided default
    // constructor, emit the zero initialization now, unless destination is
    // already zeroed.
    if (E->requiresZeroInitialization() && !Dest.isZeroed()) {
      switch (E->getConstructionKind()) {
      case CXXConstructExpr::CK_Delegating:
      case CXXConstructExpr::CK_Complete:
        EmitNullInitialization(Dest.getAddr(), E->getType());
        break;
      case CXXConstructExpr::CK_VirtualBase:
      case CXXConstructExpr::CK_NonVirtualBase:
        EmitNullBaseClassInitialization(*this, Dest.getAddr(), CD->getParent());
        break;
      }
    }
    
    // If this is a call to a trivial default constructor, do nothing.
    if (CD->isTrivial() && CD->isDefaultConstructor())
      return;
    
    // Elide the constructor if we're constructing from a temporary.
    // The temporary check is required because Sema sets this on NRVO
    // returns.
    if (getLangOpts().ElideConstructors && E->isElidable()) {
      assert(getContext().hasSameUnqualifiedType(E->getType(),
                                                 E->getArg(0)->getType()));
      if (E->getArg(0)->isTemporaryObject(getContext(), CD->getParent())) {
        EmitAggExpr(E->getArg(0), Dest);
        return;
      }
    }
    
    if (const ConstantArrayType *arrayType 
          = getContext().getAsConstantArrayType(E->getType())) {
      EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddr(), E);
    } else {
      CXXCtorType Type = Ctor_Complete;
      bool ForVirtualBase = false;
      bool Delegating = false;
      
      switch (E->getConstructionKind()) {
       case CXXConstructExpr::CK_Delegating:
        // We should be emitting a constructor; GlobalDecl will assert this
        Type = CurGD.getCtorType();
        Delegating = true;
        break;
  
       case CXXConstructExpr::CK_Complete:
        Type = Ctor_Complete;
        break;
  
       case CXXConstructExpr::CK_VirtualBase:
        ForVirtualBase = true;
        // fall-through
  
       case CXXConstructExpr::CK_NonVirtualBase:
        Type = Ctor_Base;
      }
      
      // Call the constructor.
      EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating, Dest.getAddr(),
                             E);
    }
  }
  
  void
  CodeGenFunction::EmitSynthesizedCXXCopyCtor(llvm::Value *Dest, 
                                              llvm::Value *Src,
                                              const Expr *Exp) {
    if (const ExprWithCleanups *E = dyn_cast<ExprWithCleanups>(Exp))
      Exp = E->getSubExpr();
    assert(isa<CXXConstructExpr>(Exp) && 
           "EmitSynthesizedCXXCopyCtor - unknown copy ctor expr");
    const CXXConstructExpr* E = cast<CXXConstructExpr>(Exp);
    const CXXConstructorDecl *CD = E->getConstructor();
    RunCleanupsScope Scope(*this);
    
    // If we require zero initialization before (or instead of) calling the
    // constructor, as can be the case with a non-user-provided default
    // constructor, emit the zero initialization now.
    // FIXME. Do I still need this for a copy ctor synthesis?
    if (E->requiresZeroInitialization())
      EmitNullInitialization(Dest, E->getType());
    
    assert(!getContext().getAsConstantArrayType(E->getType())
           && "EmitSynthesizedCXXCopyCtor - Copied-in Array");
    EmitSynthesizedCXXCopyCtorCall(CD, Dest, Src, E);
  }
  
  static CharUnits CalculateCookiePadding(CodeGenFunction &CGF,
                                          const CXXNewExpr *E) {
    if (!E->isArray())
      return CharUnits::Zero();
  
    // No cookie is required if the operator new[] being used is the
    // reserved placement operator new[].
    if (E->getOperatorNew()->isReservedGlobalPlacementOperator())
      return CharUnits::Zero();
  
    return CGF.CGM.getCXXABI().GetArrayCookieSize(E);
  }
  
  static llvm::Value *EmitCXXNewAllocSize(CodeGenFunction &CGF,
                                          const CXXNewExpr *e,
                                          unsigned minElements,
                                          llvm::Value *&numElements,
                                          llvm::Value *&sizeWithoutCookie) {
    QualType type = e->getAllocatedType();
  
    if (!e->isArray()) {
      CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
      sizeWithoutCookie
        = llvm::ConstantInt::get(CGF.SizeTy, typeSize.getQuantity());
      return sizeWithoutCookie;
    }
  
    // The width of size_t.
    unsigned sizeWidth = CGF.SizeTy->getBitWidth();
  
    // Figure out the cookie size.
    llvm::APInt cookieSize(sizeWidth,
                           CalculateCookiePadding(CGF, e).getQuantity());
  
    // Emit the array size expression.
    // We multiply the size of all dimensions for NumElements.
    // e.g for 'int[2][3]', ElemType is 'int' and NumElements is 6.
    numElements = CGF.EmitScalarExpr(e->getArraySize());
    assert(isa<llvm::IntegerType>(numElements->getType()));
  
    // The number of elements can be have an arbitrary integer type;
    // essentially, we need to multiply it by a constant factor, add a
    // cookie size, and verify that the result is representable as a
    // size_t.  That's just a gloss, though, and it's wrong in one
    // important way: if the count is negative, it's an error even if
    // the cookie size would bring the total size >= 0.
    bool isSigned 
      = e->getArraySize()->getType()->isSignedIntegerOrEnumerationType();
    llvm::IntegerType *numElementsType
      = cast<llvm::IntegerType>(numElements->getType());
    unsigned numElementsWidth = numElementsType->getBitWidth();
  
    // Compute the constant factor.
    llvm::APInt arraySizeMultiplier(sizeWidth, 1);
    while (const ConstantArrayType *CAT
               = CGF.getContext().getAsConstantArrayType(type)) {
      type = CAT->getElementType();
      arraySizeMultiplier *= CAT->getSize();
    }
  
    CharUnits typeSize = CGF.getContext().getTypeSizeInChars(type);
    llvm::APInt typeSizeMultiplier(sizeWidth, typeSize.getQuantity());
    typeSizeMultiplier *= arraySizeMultiplier;
  
    // This will be a size_t.
    llvm::Value *size;
    
    // If someone is doing 'new int[42]' there is no need to do a dynamic check.
    // Don't bloat the -O0 code.
    if (llvm::ConstantInt *numElementsC =
          dyn_cast<llvm::ConstantInt>(numElements)) {
      const llvm::APInt &count = numElementsC->getValue();
  
      bool hasAnyOverflow = false;
  
      // If 'count' was a negative number, it's an overflow.
      if (isSigned && count.isNegative())
        hasAnyOverflow = true;
  
      // We want to do all this arithmetic in size_t.  If numElements is
      // wider than that, check whether it's already too big, and if so,
      // overflow.
      else if (numElementsWidth > sizeWidth &&
               numElementsWidth - sizeWidth > count.countLeadingZeros())
        hasAnyOverflow = true;
  
      // Okay, compute a count at the right width.
      llvm::APInt adjustedCount = count.zextOrTrunc(sizeWidth);
  
      // If there is a brace-initializer, we cannot allocate fewer elements than
      // there are initializers. If we do, that's treated like an overflow.
      if (adjustedCount.ult(minElements))
        hasAnyOverflow = true;
  
      // Scale numElements by that.  This might overflow, but we don't
      // care because it only overflows if allocationSize does, too, and
      // if that overflows then we shouldn't use this.
      numElements = llvm::ConstantInt::get(CGF.SizeTy,
                                           adjustedCount * arraySizeMultiplier);
  
      // Compute the size before cookie, and track whether it overflowed.
      bool overflow;
      llvm::APInt allocationSize
        = adjustedCount.umul_ov(typeSizeMultiplier, overflow);
      hasAnyOverflow |= overflow;
  
      // Add in the cookie, and check whether it's overflowed.
      if (cookieSize != 0) {
        // Save the current size without a cookie.  This shouldn't be
        // used if there was overflow.
        sizeWithoutCookie = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
  
        allocationSize = allocationSize.uadd_ov(cookieSize, overflow);
        hasAnyOverflow |= overflow;
      }
  
      // On overflow, produce a -1 so operator new will fail.
      if (hasAnyOverflow) {
        size = llvm::Constant::getAllOnesValue(CGF.SizeTy);
      } else {
        size = llvm::ConstantInt::get(CGF.SizeTy, allocationSize);
      }
  
    // Otherwise, we might need to use the overflow intrinsics.
    } else {
      // There are up to five conditions we need to test for:
      // 1) if isSigned, we need to check whether numElements is negative;
      // 2) if numElementsWidth > sizeWidth, we need to check whether
      //   numElements is larger than something representable in size_t;
      // 3) if minElements > 0, we need to check whether numElements is smaller
      //    than that.
      // 4) we need to compute
      //      sizeWithoutCookie := numElements * typeSizeMultiplier
      //    and check whether it overflows; and
      // 5) if we need a cookie, we need to compute
      //      size := sizeWithoutCookie + cookieSize
      //    and check whether it overflows.
  
      llvm::Value *hasOverflow = nullptr;
  
      // If numElementsWidth > sizeWidth, then one way or another, we're
      // going to have to do a comparison for (2), and this happens to
      // take care of (1), too.
      if (numElementsWidth > sizeWidth) {
        llvm::APInt threshold(numElementsWidth, 1);
        threshold <<= sizeWidth;
  
        llvm::Value *thresholdV
          = llvm::ConstantInt::get(numElementsType, threshold);
  
        hasOverflow = CGF.Builder.CreateICmpUGE(numElements, thresholdV);
        numElements = CGF.Builder.CreateTrunc(numElements, CGF.SizeTy);
  
      // Otherwise, if we're signed, we want to sext up to size_t.
      } else if (isSigned) {
        if (numElementsWidth < sizeWidth)
          numElements = CGF.Builder.CreateSExt(numElements, CGF.SizeTy);
        
        // If there's a non-1 type size multiplier, then we can do the
        // signedness check at the same time as we do the multiply
        // because a negative number times anything will cause an
        // unsigned overflow.  Otherwise, we have to do it here. But at least
        // in this case, we can subsume the >= minElements check.
        if (typeSizeMultiplier == 1)
          hasOverflow = CGF.Builder.CreateICmpSLT(numElements,
                                llvm::ConstantInt::get(CGF.SizeTy, minElements));
  
      // Otherwise, zext up to size_t if necessary.
      } else if (numElementsWidth < sizeWidth) {
        numElements = CGF.Builder.CreateZExt(numElements, CGF.SizeTy);
      }
  
      assert(numElements->getType() == CGF.SizeTy);
  
      if (minElements) {
        // Don't allow allocation of fewer elements than we have initializers.
        if (!hasOverflow) {
          hasOverflow = CGF.Builder.CreateICmpULT(numElements,
                                llvm::ConstantInt::get(CGF.SizeTy, minElements));
        } else if (numElementsWidth > sizeWidth) {
          // The other existing overflow subsumes this check.
          // We do an unsigned comparison, since any signed value < -1 is
          // taken care of either above or below.
          hasOverflow = CGF.Builder.CreateOr(hasOverflow,
                            CGF.Builder.CreateICmpULT(numElements,
                                llvm::ConstantInt::get(CGF.SizeTy, minElements)));
        }
      }
  
      size = numElements;
  
      // Multiply by the type size if necessary.  This multiplier
      // includes all the factors for nested arrays.
      //
      // This step also causes numElements to be scaled up by the
      // nested-array factor if necessary.  Overflow on this computation
      // can be ignored because the result shouldn't be used if
      // allocation fails.
      if (typeSizeMultiplier != 1) {
        llvm::Value *umul_with_overflow
          = CGF.CGM.getIntrinsic(llvm::Intrinsic::umul_with_overflow, CGF.SizeTy);
  
        llvm::Value *tsmV =
          llvm::ConstantInt::get(CGF.SizeTy, typeSizeMultiplier);
        llvm::Value *result =
            CGF.Builder.CreateCall(umul_with_overflow, {size, tsmV});
  
        llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
        if (hasOverflow)
          hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
        else
          hasOverflow = overflowed;
  
        size = CGF.Builder.CreateExtractValue(result, 0);
  
        // Also scale up numElements by the array size multiplier.
        if (arraySizeMultiplier != 1) {
          // If the base element type size is 1, then we can re-use the
          // multiply we just did.
          if (typeSize.isOne()) {
            assert(arraySizeMultiplier == typeSizeMultiplier);
            numElements = size;
  
          // Otherwise we need a separate multiply.
          } else {
            llvm::Value *asmV =
              llvm::ConstantInt::get(CGF.SizeTy, arraySizeMultiplier);
            numElements = CGF.Builder.CreateMul(numElements, asmV);
          }
        }
      } else {
        // numElements doesn't need to be scaled.
        assert(arraySizeMultiplier == 1);
      }
      
      // Add in the cookie size if necessary.
      if (cookieSize != 0) {
        sizeWithoutCookie = size;
  
        llvm::Value *uadd_with_overflow
          = CGF.CGM.getIntrinsic(llvm::Intrinsic::uadd_with_overflow, CGF.SizeTy);
  
        llvm::Value *cookieSizeV = llvm::ConstantInt::get(CGF.SizeTy, cookieSize);
        llvm::Value *result =
            CGF.Builder.CreateCall(uadd_with_overflow, {size, cookieSizeV});
  
        llvm::Value *overflowed = CGF.Builder.CreateExtractValue(result, 1);
        if (hasOverflow)
          hasOverflow = CGF.Builder.CreateOr(hasOverflow, overflowed);
        else
          hasOverflow = overflowed;
  
        size = CGF.Builder.CreateExtractValue(result, 0);
      }
  
      // If we had any possibility of dynamic overflow, make a select to
      // overwrite 'size' with an all-ones value, which should cause
      // operator new to throw.
      if (hasOverflow)
        size = CGF.Builder.CreateSelect(hasOverflow,
                                   llvm::Constant::getAllOnesValue(CGF.SizeTy),
                                        size);
    }
  
    if (cookieSize == 0)
      sizeWithoutCookie = size;
    else
      assert(sizeWithoutCookie && "didn't set sizeWithoutCookie?");
  
    return size;
  }
  
  static void StoreAnyExprIntoOneUnit(CodeGenFunction &CGF, const Expr *Init,
                                      QualType AllocType, llvm::Value *NewPtr) {
    // FIXME: Refactor with EmitExprAsInit.
    CharUnits Alignment = CGF.getContext().getTypeAlignInChars(AllocType);
    switch (CGF.getEvaluationKind(AllocType)) {
    case TEK_Scalar:
      CGF.EmitScalarInit(Init, nullptr,
                         CGF.MakeAddrLValue(NewPtr, AllocType, Alignment), false);
      return;
    case TEK_Complex:
      CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType,
                                                             Alignment),
                                    /*isInit*/ true);
      return;
    case TEK_Aggregate: {
      AggValueSlot Slot
        = AggValueSlot::forAddr(NewPtr, Alignment, AllocType.getQualifiers(),
                                AggValueSlot::IsDestructed,
                                AggValueSlot::DoesNotNeedGCBarriers,
                                AggValueSlot::IsNotAliased);
      CGF.EmitAggExpr(Init, Slot);
      return;
    }
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  void CodeGenFunction::EmitNewArrayInitializer(
      const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
      llvm::Value *BeginPtr, llvm::Value *NumElements,
      llvm::Value *AllocSizeWithoutCookie) {
    // If we have a type with trivial initialization and no initializer,
    // there's nothing to do.
    if (!E->hasInitializer())
      return;
  
    llvm::Value *CurPtr = BeginPtr;
  
    unsigned InitListElements = 0;
  
    const Expr *Init = E->getInitializer();
    llvm::AllocaInst *EndOfInit = nullptr;
    QualType::DestructionKind DtorKind = ElementType.isDestructedType();
    EHScopeStack::stable_iterator Cleanup;
    llvm::Instruction *CleanupDominator = nullptr;
  
    // If the initializer is an initializer list, first do the explicit elements.
    if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
      InitListElements = ILE->getNumInits();
  
      // If this is a multi-dimensional array new, we will initialize multiple
      // elements with each init list element.
      QualType AllocType = E->getAllocatedType();
      if (const ConstantArrayType *CAT = dyn_cast_or_null<ConstantArrayType>(
              AllocType->getAsArrayTypeUnsafe())) {
        unsigned AS = CurPtr->getType()->getPointerAddressSpace();
        ElementTy = ConvertTypeForMem(AllocType);
        llvm::Type *AllocPtrTy = ElementTy->getPointerTo(AS);
        CurPtr = Builder.CreateBitCast(CurPtr, AllocPtrTy);
        InitListElements *= getContext().getConstantArrayElementCount(CAT);
      }
  
      // Enter a partial-destruction Cleanup if necessary.
      if (needsEHCleanup(DtorKind)) {
        // In principle we could tell the Cleanup where we are more
        // directly, but the control flow can get so varied here that it
        // would actually be quite complex.  Therefore we go through an
        // alloca.
        EndOfInit = CreateTempAlloca(BeginPtr->getType(), "array.init.end");
        CleanupDominator = Builder.CreateStore(BeginPtr, EndOfInit);
        pushIrregularPartialArrayCleanup(BeginPtr, EndOfInit, ElementType,
                                         getDestroyer(DtorKind));
        Cleanup = EHStack.stable_begin();
      }
  
      for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i) {
        // Tell the cleanup that it needs to destroy up to this
        // element.  TODO: some of these stores can be trivially
        // observed to be unnecessary.
        if (EndOfInit)
          Builder.CreateStore(Builder.CreateBitCast(CurPtr, BeginPtr->getType()),
                              EndOfInit);
        // FIXME: If the last initializer is an incomplete initializer list for
        // an array, and we have an array filler, we can fold together the two
        // initialization loops.
        StoreAnyExprIntoOneUnit(*this, ILE->getInit(i),
                                ILE->getInit(i)->getType(), CurPtr);
        CurPtr = Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr, 1,
                                                    "array.exp.next");
      }
  
      // The remaining elements are filled with the array filler expression.
      Init = ILE->getArrayFiller();
  
      // Extract the initializer for the individual array elements by pulling
      // out the array filler from all the nested initializer lists. This avoids
      // generating a nested loop for the initialization.
      while (Init && Init->getType()->isConstantArrayType()) {
        auto *SubILE = dyn_cast<InitListExpr>(Init);
        if (!SubILE)
          break;
        assert(SubILE->getNumInits() == 0 && "explicit inits in array filler?");
        Init = SubILE->getArrayFiller();
      }
  
      // Switch back to initializing one base element at a time.
      CurPtr = Builder.CreateBitCast(CurPtr, BeginPtr->getType());
    }
  
    // Attempt to perform zero-initialization using memset.
    auto TryMemsetInitialization = [&]() -> bool {
      // FIXME: If the type is a pointer-to-data-member under the Itanium ABI,
      // we can initialize with a memset to -1.
      if (!CGM.getTypes().isZeroInitializable(ElementType))
        return false;
  
      // Optimization: since zero initialization will just set the memory
      // to all zeroes, generate a single memset to do it in one shot.
  
      // Subtract out the size of any elements we've already initialized.
      auto *RemainingSize = AllocSizeWithoutCookie;
      if (InitListElements) {
        // We know this can't overflow; we check this when doing the allocation.
        auto *InitializedSize = llvm::ConstantInt::get(
            RemainingSize->getType(),
            getContext().getTypeSizeInChars(ElementType).getQuantity() *
                InitListElements);
        RemainingSize = Builder.CreateSub(RemainingSize, InitializedSize);
      }
  
      // Create the memset.
      CharUnits Alignment = getContext().getTypeAlignInChars(ElementType);
      Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize,
                           Alignment.getQuantity(), false);
      return true;
    };
  
    // If all elements have already been initialized, skip any further
    // initialization.
    llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
    if (ConstNum && ConstNum->getZExtValue() <= InitListElements) {
      // If there was a Cleanup, deactivate it.
      if (CleanupDominator)
        DeactivateCleanupBlock(Cleanup, CleanupDominator);
      return;
    }
  
    assert(Init && "have trailing elements to initialize but no initializer");
  
    // If this is a constructor call, try to optimize it out, and failing that
    // emit a single loop to initialize all remaining elements.
    if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(Init)) {
      CXXConstructorDecl *Ctor = CCE->getConstructor();
      if (Ctor->isTrivial()) {
        // If new expression did not specify value-initialization, then there
        // is no initialization.
        if (!CCE->requiresZeroInitialization() || Ctor->getParent()->isEmpty())
          return;
  
        if (TryMemsetInitialization())
          return;
      }
  
      // Store the new Cleanup position for irregular Cleanups.
      //
      // FIXME: Share this cleanup with the constructor call emission rather than
      // having it create a cleanup of its own.
      if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit);
  
      // Emit a constructor call loop to initialize the remaining elements.
      if (InitListElements)
        NumElements = Builder.CreateSub(
            NumElements,
            llvm::ConstantInt::get(NumElements->getType(), InitListElements));
      EmitCXXAggrConstructorCall(Ctor, NumElements, CurPtr, CCE,
                                 CCE->requiresZeroInitialization());
      return;
    }
  
    // If this is value-initialization, we can usually use memset.
    ImplicitValueInitExpr IVIE(ElementType);
    if (isa<ImplicitValueInitExpr>(Init)) {
      if (TryMemsetInitialization())
        return;
  
      // Switch to an ImplicitValueInitExpr for the element type. This handles
      // only one case: multidimensional array new of pointers to members. In
      // all other cases, we already have an initializer for the array element.
      Init = &IVIE;
    }
  
    // At this point we should have found an initializer for the individual
    // elements of the array.
    assert(getContext().hasSameUnqualifiedType(ElementType, Init->getType()) &&
           "got wrong type of element to initialize");
  
    // If we have an empty initializer list, we can usually use memset.
    if (auto *ILE = dyn_cast<InitListExpr>(Init))
      if (ILE->getNumInits() == 0 && TryMemsetInitialization())
        return;
  
    // If we have a struct whose every field is value-initialized, we can
    // usually use memset.
    if (auto *ILE = dyn_cast<InitListExpr>(Init)) {
      if (const RecordType *RType = ILE->getType()->getAs<RecordType>()) {
        if (RType->getDecl()->isStruct()) {
          unsigned NumFields = 0;
          for (auto *Field : RType->getDecl()->fields())
            if (!Field->isUnnamedBitfield())
              ++NumFields;
          if (ILE->getNumInits() == NumFields)
            for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
              if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
                --NumFields;
          if (ILE->getNumInits() == NumFields && TryMemsetInitialization())
            return;
        }
      }
    }
  
    // Create the loop blocks.
    llvm::BasicBlock *EntryBB = Builder.GetInsertBlock();
    llvm::BasicBlock *LoopBB = createBasicBlock("new.loop");
    llvm::BasicBlock *ContBB = createBasicBlock("new.loop.end");
  
    // Find the end of the array, hoisted out of the loop.
    llvm::Value *EndPtr =
      Builder.CreateInBoundsGEP(BeginPtr, NumElements, "array.end");
  
    // If the number of elements isn't constant, we have to now check if there is
    // anything left to initialize.
    if (!ConstNum) {
      llvm::Value *IsEmpty = Builder.CreateICmpEQ(CurPtr, EndPtr,
                                                  "array.isempty");
      Builder.CreateCondBr(IsEmpty, ContBB, LoopBB);
    }
  
    // Enter the loop.
    EmitBlock(LoopBB);
  
    // Set up the current-element phi.
    llvm::PHINode *CurPtrPhi =
      Builder.CreatePHI(CurPtr->getType(), 2, "array.cur");
    CurPtrPhi->addIncoming(CurPtr, EntryBB);
    CurPtr = CurPtrPhi;
  
    // Store the new Cleanup position for irregular Cleanups.
    if (EndOfInit) Builder.CreateStore(CurPtr, EndOfInit);
  
    // Enter a partial-destruction Cleanup if necessary.
    if (!CleanupDominator && needsEHCleanup(DtorKind)) {
      pushRegularPartialArrayCleanup(BeginPtr, CurPtr, ElementType,
                                     getDestroyer(DtorKind));
      Cleanup = EHStack.stable_begin();
      CleanupDominator = Builder.CreateUnreachable();
    }
  
    // Emit the initializer into this element.
    StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr);
  
    // Leave the Cleanup if we entered one.
    if (CleanupDominator) {
      DeactivateCleanupBlock(Cleanup, CleanupDominator);
      CleanupDominator->eraseFromParent();
    }
  
    // Advance to the next element by adjusting the pointer type as necessary.
    llvm::Value *NextPtr =
        Builder.CreateConstInBoundsGEP1_32(ElementTy, CurPtr, 1, "array.next");
  
    // Check whether we've gotten to the end of the array and, if so,
    // exit the loop.
    llvm::Value *IsEnd = Builder.CreateICmpEQ(NextPtr, EndPtr, "array.atend");
    Builder.CreateCondBr(IsEnd, ContBB, LoopBB);
    CurPtrPhi->addIncoming(NextPtr, Builder.GetInsertBlock());
  
    EmitBlock(ContBB);
  }
  
  static void EmitNewInitializer(CodeGenFunction &CGF, const CXXNewExpr *E,
                                 QualType ElementType, llvm::Type *ElementTy,
                                 llvm::Value *NewPtr, llvm::Value *NumElements,
                                 llvm::Value *AllocSizeWithoutCookie) {
    ApplyDebugLocation DL(CGF, E);
    if (E->isArray())
      CGF.EmitNewArrayInitializer(E, ElementType, ElementTy, NewPtr, NumElements,
                                  AllocSizeWithoutCookie);
    else if (const Expr *Init = E->getInitializer())
      StoreAnyExprIntoOneUnit(CGF, Init, E->getAllocatedType(), NewPtr);
  }
  
  /// Emit a call to an operator new or operator delete function, as implicitly
  /// created by new-expressions and delete-expressions.
  static RValue EmitNewDeleteCall(CodeGenFunction &CGF,
                                  const FunctionDecl *Callee,
                                  const FunctionProtoType *CalleeType,
                                  const CallArgList &Args) {
    llvm::Instruction *CallOrInvoke;
    llvm::Value *CalleeAddr = CGF.CGM.GetAddrOfFunction(Callee);
    RValue RV =
        CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
                         Args, CalleeType, /*chainCall=*/false),
                     CalleeAddr, ReturnValueSlot(), Args, Callee, &CallOrInvoke);
  
    /// C++1y [expr.new]p10:
    ///   [In a new-expression,] an implementation is allowed to omit a call
    ///   to a replaceable global allocation function.
    ///
    /// We model such elidable calls with the 'builtin' attribute.
    llvm::Function *Fn = dyn_cast<llvm::Function>(CalleeAddr);
    if (Callee->isReplaceableGlobalAllocationFunction() &&
        Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
      // FIXME: Add addAttribute to CallSite.
      if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke))
        CI->addAttribute(llvm::AttributeSet::FunctionIndex,
                         llvm::Attribute::Builtin);
      else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke))
        II->addAttribute(llvm::AttributeSet::FunctionIndex,
                         llvm::Attribute::Builtin);
      else
        llvm_unreachable("unexpected kind of call instruction");
    }
  
    return RV;
  }
  
  RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
                                                   const Expr *Arg,
                                                   bool IsDelete) {
    CallArgList Args;
    const Stmt *ArgS = Arg;
    EmitCallArgs(Args, *Type->param_type_begin(),
                 ConstExprIterator(&ArgS), ConstExprIterator(&ArgS + 1));
    // Find the allocation or deallocation function that we're calling.
    ASTContext &Ctx = getContext();
    DeclarationName Name = Ctx.DeclarationNames
        .getCXXOperatorName(IsDelete ? OO_Delete : OO_New);
    for (auto *Decl : Ctx.getTranslationUnitDecl()->lookup(Name))
      if (auto *FD = dyn_cast<FunctionDecl>(Decl))
        if (Ctx.hasSameType(FD->getType(), QualType(Type, 0)))
          return EmitNewDeleteCall(*this, cast<FunctionDecl>(Decl), Type, Args);
    llvm_unreachable("predeclared global operator new/delete is missing");
  }
  
  namespace {
    /// A cleanup to call the given 'operator delete' function upon
    /// abnormal exit from a new expression.
    class CallDeleteDuringNew : public EHScopeStack::Cleanup {
      size_t NumPlacementArgs;
      const FunctionDecl *OperatorDelete;
      llvm::Value *Ptr;
      llvm::Value *AllocSize;
  
      RValue *getPlacementArgs() { return reinterpret_cast<RValue*>(this+1); }
  
    public:
      static size_t getExtraSize(size_t NumPlacementArgs) {
        return NumPlacementArgs * sizeof(RValue);
      }
  
      CallDeleteDuringNew(size_t NumPlacementArgs,
                          const FunctionDecl *OperatorDelete,
                          llvm::Value *Ptr,
                          llvm::Value *AllocSize) 
        : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
          Ptr(Ptr), AllocSize(AllocSize) {}
  
      void setPlacementArg(unsigned I, RValue Arg) {
        assert(I < NumPlacementArgs && "index out of range");
        getPlacementArgs()[I] = Arg;
      }
  
      void Emit(CodeGenFunction &CGF, Flags flags) override {
        const FunctionProtoType *FPT
          = OperatorDelete->getType()->getAs<FunctionProtoType>();
        assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
               (FPT->getNumParams() == 2 && NumPlacementArgs == 0));
  
        CallArgList DeleteArgs;
  
        // The first argument is always a void*.
        FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
        DeleteArgs.add(RValue::get(Ptr), *AI++);
  
        // A member 'operator delete' can take an extra 'size_t' argument.
        if (FPT->getNumParams() == NumPlacementArgs + 2)
          DeleteArgs.add(RValue::get(AllocSize), *AI++);
  
        // Pass the rest of the arguments, which must match exactly.
        for (unsigned I = 0; I != NumPlacementArgs; ++I)
          DeleteArgs.add(getPlacementArgs()[I], *AI++);
  
        // Call 'operator delete'.
        EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
      }
    };
  
    /// A cleanup to call the given 'operator delete' function upon
    /// abnormal exit from a new expression when the new expression is
    /// conditional.
    class CallDeleteDuringConditionalNew : public EHScopeStack::Cleanup {
      size_t NumPlacementArgs;
      const FunctionDecl *OperatorDelete;
      DominatingValue<RValue>::saved_type Ptr;
      DominatingValue<RValue>::saved_type AllocSize;
  
      DominatingValue<RValue>::saved_type *getPlacementArgs() {
        return reinterpret_cast<DominatingValue<RValue>::saved_type*>(this+1);
      }
  
    public:
      static size_t getExtraSize(size_t NumPlacementArgs) {
        return NumPlacementArgs * sizeof(DominatingValue<RValue>::saved_type);
      }
  
      CallDeleteDuringConditionalNew(size_t NumPlacementArgs,
                                     const FunctionDecl *OperatorDelete,
                                     DominatingValue<RValue>::saved_type Ptr,
                                DominatingValue<RValue>::saved_type AllocSize)
        : NumPlacementArgs(NumPlacementArgs), OperatorDelete(OperatorDelete),
          Ptr(Ptr), AllocSize(AllocSize) {}
  
      void setPlacementArg(unsigned I, DominatingValue<RValue>::saved_type Arg) {
        assert(I < NumPlacementArgs && "index out of range");
        getPlacementArgs()[I] = Arg;
      }
  
      void Emit(CodeGenFunction &CGF, Flags flags) override {
        const FunctionProtoType *FPT
          = OperatorDelete->getType()->getAs<FunctionProtoType>();
        assert(FPT->getNumParams() == NumPlacementArgs + 1 ||
               (FPT->getNumParams() == 2 && NumPlacementArgs == 0));
  
        CallArgList DeleteArgs;
  
        // The first argument is always a void*.
        FunctionProtoType::param_type_iterator AI = FPT->param_type_begin();
        DeleteArgs.add(Ptr.restore(CGF), *AI++);
  
        // A member 'operator delete' can take an extra 'size_t' argument.
        if (FPT->getNumParams() == NumPlacementArgs + 2) {
          RValue RV = AllocSize.restore(CGF);
          DeleteArgs.add(RV, *AI++);
        }
  
        // Pass the rest of the arguments, which must match exactly.
        for (unsigned I = 0; I != NumPlacementArgs; ++I) {
          RValue RV = getPlacementArgs()[I].restore(CGF);
          DeleteArgs.add(RV, *AI++);
        }
  
        // Call 'operator delete'.
        EmitNewDeleteCall(CGF, OperatorDelete, FPT, DeleteArgs);
      }
    };
  }
  
  /// Enter a cleanup to call 'operator delete' if the initializer in a
  /// new-expression throws.
  static void EnterNewDeleteCleanup(CodeGenFunction &CGF,
                                    const CXXNewExpr *E,
                                    llvm::Value *NewPtr,
                                    llvm::Value *AllocSize,
                                    const CallArgList &NewArgs) {
    // If we're not inside a conditional branch, then the cleanup will
    // dominate and we can do the easier (and more efficient) thing.
    if (!CGF.isInConditionalBranch()) {
      CallDeleteDuringNew *Cleanup = CGF.EHStack
        .pushCleanupWithExtra<CallDeleteDuringNew>(EHCleanup,
                                                   E->getNumPlacementArgs(),
                                                   E->getOperatorDelete(),
                                                   NewPtr, AllocSize);
      for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
        Cleanup->setPlacementArg(I, NewArgs[I+1].RV);
  
      return;
    }
  
    // Otherwise, we need to save all this stuff.
    DominatingValue<RValue>::saved_type SavedNewPtr =
      DominatingValue<RValue>::save(CGF, RValue::get(NewPtr));
    DominatingValue<RValue>::saved_type SavedAllocSize =
      DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
  
    CallDeleteDuringConditionalNew *Cleanup = CGF.EHStack
      .pushCleanupWithExtra<CallDeleteDuringConditionalNew>(EHCleanup,
                                                   E->getNumPlacementArgs(),
                                                   E->getOperatorDelete(),
                                                   SavedNewPtr,
                                                   SavedAllocSize);
    for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I)
      Cleanup->setPlacementArg(I,
                       DominatingValue<RValue>::save(CGF, NewArgs[I+1].RV));
  
    CGF.initFullExprCleanup();
  }
  
  llvm::Value *CodeGenFunction::EmitCXXNewExpr(const CXXNewExpr *E) {
    // The element type being allocated.
    QualType allocType = getContext().getBaseElementType(E->getAllocatedType());
  
    // 1. Build a call to the allocation function.
    FunctionDecl *allocator = E->getOperatorNew();
    const FunctionProtoType *allocatorType =
      allocator->getType()->castAs<FunctionProtoType>();
  
    CallArgList allocatorArgs;
  
    // The allocation size is the first argument.
    QualType sizeType = getContext().getSizeType();
  
    // If there is a brace-initializer, cannot allocate fewer elements than inits.
    unsigned minElements = 0;
    if (E->isArray() && E->hasInitializer()) {
      if (const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer()))
        minElements = ILE->getNumInits();
    }
  
    llvm::Value *numElements = nullptr;
    llvm::Value *allocSizeWithoutCookie = nullptr;
    llvm::Value *allocSize =
      EmitCXXNewAllocSize(*this, E, minElements, numElements,
                          allocSizeWithoutCookie);
  
    allocatorArgs.add(RValue::get(allocSize), sizeType);
  
    // We start at 1 here because the first argument (the allocation size)
    // has already been emitted.
    EmitCallArgs(allocatorArgs, allocatorType, E->placement_arg_begin(),
                 E->placement_arg_end(), /* CalleeDecl */ nullptr,
                 /*ParamsToSkip*/ 1);
  
    // Emit the allocation call.  If the allocator is a global placement
    // operator, just "inline" it directly.
    RValue RV;
    if (allocator->isReservedGlobalPlacementOperator()) {
      assert(allocatorArgs.size() == 2);
      RV = allocatorArgs[1].RV;
      // TODO: kill any unnecessary computations done for the size
      // argument.
    } else {
      RV = EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
    }
  
    // Emit a null check on the allocation result if the allocation
    // function is allowed to return null (because it has a non-throwing
    // exception spec or is the reserved placement new) and we have an
    // interesting initializer.
    bool nullCheck = E->shouldNullCheckAllocation(getContext()) &&
      (!allocType.isPODType(getContext()) || E->hasInitializer());
  
    llvm::BasicBlock *nullCheckBB = nullptr;
    llvm::BasicBlock *contBB = nullptr;
  
    llvm::Value *allocation = RV.getScalarVal();
    unsigned AS = allocation->getType()->getPointerAddressSpace();
  
    // The null-check means that the initializer is conditionally
    // evaluated.
    ConditionalEvaluation conditional(*this);
  
    if (nullCheck) {
      conditional.begin(*this);
  
      nullCheckBB = Builder.GetInsertBlock();
      llvm::BasicBlock *notNullBB = createBasicBlock("new.notnull");
      contBB = createBasicBlock("new.cont");
  
      llvm::Value *isNull = Builder.CreateIsNull(allocation, "new.isnull");
      Builder.CreateCondBr(isNull, contBB, notNullBB);
      EmitBlock(notNullBB);
    }
  
    // If there's an operator delete, enter a cleanup to call it if an
    // exception is thrown.
    EHScopeStack::stable_iterator operatorDeleteCleanup;
    llvm::Instruction *cleanupDominator = nullptr;
    if (E->getOperatorDelete() &&
        !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
      EnterNewDeleteCleanup(*this, E, allocation, allocSize, allocatorArgs);
      operatorDeleteCleanup = EHStack.stable_begin();
      cleanupDominator = Builder.CreateUnreachable();
    }
  
    assert((allocSize == allocSizeWithoutCookie) ==
           CalculateCookiePadding(*this, E).isZero());
    if (allocSize != allocSizeWithoutCookie) {
      assert(E->isArray());
      allocation = CGM.getCXXABI().InitializeArrayCookie(*this, allocation,
                                                         numElements,
                                                         E, allocType);
    }
  
    llvm::Type *elementTy = ConvertTypeForMem(allocType);
    llvm::Type *elementPtrTy = elementTy->getPointerTo(AS);
    llvm::Value *result = Builder.CreateBitCast(allocation, elementPtrTy);
  
    EmitNewInitializer(*this, E, allocType, elementTy, result, numElements,
                       allocSizeWithoutCookie);
    if (E->isArray()) {
      // NewPtr is a pointer to the base element type.  If we're
      // allocating an array of arrays, we'll need to cast back to the
      // array pointer type.
      llvm::Type *resultType = ConvertTypeForMem(E->getType());
      if (result->getType() != resultType)
        result = Builder.CreateBitCast(result, resultType);
    }
  
    // Deactivate the 'operator delete' cleanup if we finished
    // initialization.
    if (operatorDeleteCleanup.isValid()) {
      DeactivateCleanupBlock(operatorDeleteCleanup, cleanupDominator);
      cleanupDominator->eraseFromParent();
    }
  
    if (nullCheck) {
      conditional.end(*this);
  
      llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
      EmitBlock(contBB);
  
      llvm::PHINode *PHI = Builder.CreatePHI(result->getType(), 2);
      PHI->addIncoming(result, notNullBB);
      PHI->addIncoming(llvm::Constant::getNullValue(result->getType()),
                       nullCheckBB);
  
      result = PHI;
    }
    
    return result;
  }
  
  void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
                                       llvm::Value *Ptr,
                                       QualType DeleteTy) {
    assert(DeleteFD->getOverloadedOperator() == OO_Delete);
  
    const FunctionProtoType *DeleteFTy =
      DeleteFD->getType()->getAs<FunctionProtoType>();
  
    CallArgList DeleteArgs;
  
    // Check if we need to pass the size to the delete operator.
    llvm::Value *Size = nullptr;
    QualType SizeTy;
    if (DeleteFTy->getNumParams() == 2) {
      SizeTy = DeleteFTy->getParamType(1);
      CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
      Size = llvm::ConstantInt::get(ConvertType(SizeTy), 
                                    DeleteTypeSize.getQuantity());
    }
  
    QualType ArgTy = DeleteFTy->getParamType(0);
    llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
    DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
  
    if (Size)
      DeleteArgs.add(RValue::get(Size), SizeTy);
  
    // Emit the call to delete.
    EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
  }
  
  namespace {
    /// Calls the given 'operator delete' on a single object.
    struct CallObjectDelete : EHScopeStack::Cleanup {
      llvm::Value *Ptr;
      const FunctionDecl *OperatorDelete;
      QualType ElementType;
  
      CallObjectDelete(llvm::Value *Ptr,
                       const FunctionDecl *OperatorDelete,
                       QualType ElementType)
        : Ptr(Ptr), OperatorDelete(OperatorDelete), ElementType(ElementType) {}
  
      void Emit(CodeGenFunction &CGF, Flags flags) override {
        CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType);
      }
    };
  }
  
  void
  CodeGenFunction::pushCallObjectDeleteCleanup(const FunctionDecl *OperatorDelete,
                                               llvm::Value *CompletePtr,
                                               QualType ElementType) {
    EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup, CompletePtr,
                                          OperatorDelete, ElementType);
  }
  
  /// Emit the code for deleting a single object.
  static void EmitObjectDelete(CodeGenFunction &CGF,
                               const CXXDeleteExpr *DE,
                               llvm::Value *Ptr,
                               QualType ElementType) {
    // Find the destructor for the type, if applicable.  If the
    // destructor is virtual, we'll just emit the vcall and return.
    const CXXDestructorDecl *Dtor = nullptr;
    if (const RecordType *RT = ElementType->getAs<RecordType>()) {
      CXXRecordDecl *RD = cast<CXXRecordDecl>(RT->getDecl());
      if (RD->hasDefinition() && !RD->hasTrivialDestructor()) {
        Dtor = RD->getDestructor();
  
        if (Dtor->isVirtual()) {
          CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
                                                      Dtor);
          return;
        }
      }
    }
  
    // Make sure that we call delete even if the dtor throws.
    // This doesn't have to a conditional cleanup because we're going
    // to pop it off in a second.
    const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
    CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
                                              Ptr, OperatorDelete, ElementType);
  
    if (Dtor)
      CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
                                /*ForVirtualBase=*/false,
                                /*Delegating=*/false,
                                Ptr);
    else if (CGF.getLangOpts().ObjCAutoRefCount &&
             ElementType->isObjCLifetimeType()) {
      switch (ElementType.getObjCLifetime()) {
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
      case Qualifiers::OCL_Autoreleasing:
        break;
  
      case Qualifiers::OCL_Strong: {
        // Load the pointer value.
        llvm::Value *PtrValue = CGF.Builder.CreateLoad(Ptr, 
                                               ElementType.isVolatileQualified());
          
        CGF.EmitARCRelease(PtrValue, ARCPreciseLifetime);
        break;
      }
          
      case Qualifiers::OCL_Weak:
        CGF.EmitARCDestroyWeak(Ptr);
        break;
      }
    }
             
    CGF.PopCleanupBlock();
  }
  
  namespace {
    /// Calls the given 'operator delete' on an array of objects.
    struct CallArrayDelete : EHScopeStack::Cleanup {
      llvm::Value *Ptr;
      const FunctionDecl *OperatorDelete;
      llvm::Value *NumElements;
      QualType ElementType;
      CharUnits CookieSize;
  
      CallArrayDelete(llvm::Value *Ptr,
                      const FunctionDecl *OperatorDelete,
                      llvm::Value *NumElements,
                      QualType ElementType,
                      CharUnits CookieSize)
        : Ptr(Ptr), OperatorDelete(OperatorDelete), NumElements(NumElements),
          ElementType(ElementType), CookieSize(CookieSize) {}
  
      void Emit(CodeGenFunction &CGF, Flags flags) override {
        const FunctionProtoType *DeleteFTy =
          OperatorDelete->getType()->getAs<FunctionProtoType>();
        assert(DeleteFTy->getNumParams() == 1 || DeleteFTy->getNumParams() == 2);
  
        CallArgList Args;
        
        // Pass the pointer as the first argument.
        QualType VoidPtrTy = DeleteFTy->getParamType(0);
        llvm::Value *DeletePtr
          = CGF.Builder.CreateBitCast(Ptr, CGF.ConvertType(VoidPtrTy));
        Args.add(RValue::get(DeletePtr), VoidPtrTy);
  
        // Pass the original requested size as the second argument.
        if (DeleteFTy->getNumParams() == 2) {
          QualType size_t = DeleteFTy->getParamType(1);
          llvm::IntegerType *SizeTy
            = cast<llvm::IntegerType>(CGF.ConvertType(size_t));
          
          CharUnits ElementTypeSize =
            CGF.CGM.getContext().getTypeSizeInChars(ElementType);
  
          // The size of an element, multiplied by the number of elements.
          llvm::Value *Size
            = llvm::ConstantInt::get(SizeTy, ElementTypeSize.getQuantity());
          if (NumElements)
            Size = CGF.Builder.CreateMul(Size, NumElements);
  
          // Plus the size of the cookie if applicable.
          if (!CookieSize.isZero()) {
            llvm::Value *CookieSizeV
              = llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity());
            Size = CGF.Builder.CreateAdd(Size, CookieSizeV);
          }
  
          Args.add(RValue::get(Size), size_t);
        }
  
        // Emit the call to delete.
        EmitNewDeleteCall(CGF, OperatorDelete, DeleteFTy, Args);
      }
    };
  }
  
  /// Emit the code for deleting an array of objects.
  static void EmitArrayDelete(CodeGenFunction &CGF,
                              const CXXDeleteExpr *E,
                              llvm::Value *deletedPtr,
                              QualType elementType) {
    llvm::Value *numElements = nullptr;
    llvm::Value *allocatedPtr = nullptr;
    CharUnits cookieSize;
    CGF.CGM.getCXXABI().ReadArrayCookie(CGF, deletedPtr, E, elementType,
                                        numElements, allocatedPtr, cookieSize);
  
    assert(allocatedPtr && "ReadArrayCookie didn't set allocated pointer");
  
    // Make sure that we call delete even if one of the dtors throws.
    const FunctionDecl *operatorDelete = E->getOperatorDelete();
    CGF.EHStack.pushCleanup<CallArrayDelete>(NormalAndEHCleanup,
                                             allocatedPtr, operatorDelete,
                                             numElements, elementType,
                                             cookieSize);
  
    // Destroy the elements.
    if (QualType::DestructionKind dtorKind = elementType.isDestructedType()) {
      assert(numElements && "no element count for a type with a destructor!");
  
      llvm::Value *arrayEnd =
        CGF.Builder.CreateInBoundsGEP(deletedPtr, numElements, "delete.end");
  
      // Note that it is legal to allocate a zero-length array, and we
      // can never fold the check away because the length should always
      // come from a cookie.
      CGF.emitArrayDestroy(deletedPtr, arrayEnd, elementType,
                           CGF.getDestroyer(dtorKind),
                           /*checkZeroLength*/ true,
                           CGF.needsEHCleanup(dtorKind));
    }
  
    // Pop the cleanup block.
    CGF.PopCleanupBlock();
  }
  
  void CodeGenFunction::EmitCXXDeleteExpr(const CXXDeleteExpr *E) {
    const Expr *Arg = E->getArgument();
    llvm::Value *Ptr = EmitScalarExpr(Arg);
  
    // Null check the pointer.
    llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
    llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
  
    llvm::Value *IsNull = Builder.CreateIsNull(Ptr, "isnull");
  
    Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
    EmitBlock(DeleteNotNull);
  
    // We might be deleting a pointer to array.  If so, GEP down to the
    // first non-array element.
    // (this assumes that A(*)[3][7] is converted to [3 x [7 x %A]]*)
    QualType DeleteTy = Arg->getType()->getAs<PointerType>()->getPointeeType();
    if (DeleteTy->isConstantArrayType()) {
      llvm::Value *Zero = Builder.getInt32(0);
      SmallVector<llvm::Value*,8> GEP;
  
      GEP.push_back(Zero); // point at the outermost array
  
      // For each layer of array type we're pointing at:
      while (const ConstantArrayType *Arr
               = getContext().getAsConstantArrayType(DeleteTy)) {
        // 1. Unpeel the array type.
        DeleteTy = Arr->getElementType();
  
        // 2. GEP to the first element of the array.
        GEP.push_back(Zero);
      }
  
      Ptr = Builder.CreateInBoundsGEP(Ptr, GEP, "del.first");
    }
  
    assert(ConvertTypeForMem(DeleteTy) ==
           cast<llvm::PointerType>(Ptr->getType())->getElementType());
  
    if (E->isArrayForm()) {
      EmitArrayDelete(*this, E, Ptr, DeleteTy);
    } else {
      EmitObjectDelete(*this, E, Ptr, DeleteTy);
    }
  
    EmitBlock(DeleteEnd);
  }
  
  static bool isGLValueFromPointerDeref(const Expr *E) {
    E = E->IgnoreParens();
  
    if (const auto *CE = dyn_cast<CastExpr>(E)) {
      if (!CE->getSubExpr()->isGLValue())
        return false;
      return isGLValueFromPointerDeref(CE->getSubExpr());
    }
  
    if (const auto *OVE = dyn_cast<OpaqueValueExpr>(E))
      return isGLValueFromPointerDeref(OVE->getSourceExpr());
  
    if (const auto *BO = dyn_cast<BinaryOperator>(E))
      if (BO->getOpcode() == BO_Comma)
        return isGLValueFromPointerDeref(BO->getRHS());
  
    if (const auto *ACO = dyn_cast<AbstractConditionalOperator>(E))
      return isGLValueFromPointerDeref(ACO->getTrueExpr()) ||
             isGLValueFromPointerDeref(ACO->getFalseExpr());
  
    // C++11 [expr.sub]p1:
    //   The expression E1[E2] is identical (by definition) to *((E1)+(E2))
    if (isa<ArraySubscriptExpr>(E))
      return true;
  
    if (const auto *UO = dyn_cast<UnaryOperator>(E))
      if (UO->getOpcode() == UO_Deref)
        return true;
  
    return false;
  }
  
  static llvm::Value *EmitTypeidFromVTable(CodeGenFunction &CGF, const Expr *E,
                                           llvm::Type *StdTypeInfoPtrTy) {
    // Get the vtable pointer.
    llvm::Value *ThisPtr = CGF.EmitLValue(E).getAddress();
  
    // C++ [expr.typeid]p2:
    //   If the glvalue expression is obtained by applying the unary * operator to
    //   a pointer and the pointer is a null pointer value, the typeid expression
    //   throws the std::bad_typeid exception.
    //
    // However, this paragraph's intent is not clear.  We choose a very generous
    // interpretation which implores us to consider comma operators, conditional
    // operators, parentheses and other such constructs.
    QualType SrcRecordTy = E->getType();
    if (CGF.CGM.getCXXABI().shouldTypeidBeNullChecked(
            isGLValueFromPointerDeref(E), SrcRecordTy)) {
      llvm::BasicBlock *BadTypeidBlock =
          CGF.createBasicBlock("typeid.bad_typeid");
      llvm::BasicBlock *EndBlock = CGF.createBasicBlock("typeid.end");
  
      llvm::Value *IsNull = CGF.Builder.CreateIsNull(ThisPtr);
      CGF.Builder.CreateCondBr(IsNull, BadTypeidBlock, EndBlock);
  
      CGF.EmitBlock(BadTypeidBlock);
      CGF.CGM.getCXXABI().EmitBadTypeidCall(CGF);
      CGF.EmitBlock(EndBlock);
    }
  
    return CGF.CGM.getCXXABI().EmitTypeid(CGF, SrcRecordTy, ThisPtr,
                                          StdTypeInfoPtrTy);
  }
  
  llvm::Value *CodeGenFunction::EmitCXXTypeidExpr(const CXXTypeidExpr *E) {
    llvm::Type *StdTypeInfoPtrTy = 
      ConvertType(E->getType())->getPointerTo();
    
    if (E->isTypeOperand()) {
      llvm::Constant *TypeInfo =
          CGM.GetAddrOfRTTIDescriptor(E->getTypeOperand(getContext()));
      return Builder.CreateBitCast(TypeInfo, StdTypeInfoPtrTy);
    }
  
    // C++ [expr.typeid]p2:
    //   When typeid is applied to a glvalue expression whose type is a
    //   polymorphic class type, the result refers to a std::type_info object
    //   representing the type of the most derived object (that is, the dynamic
    //   type) to which the glvalue refers.
    if (E->isPotentiallyEvaluated())
      return EmitTypeidFromVTable(*this, E->getExprOperand(), 
                                  StdTypeInfoPtrTy);
  
    QualType OperandTy = E->getExprOperand()->getType();
    return Builder.CreateBitCast(CGM.GetAddrOfRTTIDescriptor(OperandTy),
                                 StdTypeInfoPtrTy);
  }
  
  static llvm::Value *EmitDynamicCastToNull(CodeGenFunction &CGF,
                                            QualType DestTy) {
    llvm::Type *DestLTy = CGF.ConvertType(DestTy);
    if (DestTy->isPointerType())
      return llvm::Constant::getNullValue(DestLTy);
  
    /// C++ [expr.dynamic.cast]p9:
    ///   A failed cast to reference type throws std::bad_cast
    if (!CGF.CGM.getCXXABI().EmitBadCastCall(CGF))
      return nullptr;
  
    CGF.EmitBlock(CGF.createBasicBlock("dynamic_cast.end"));
    return llvm::UndefValue::get(DestLTy);
  }
  
  llvm::Value *CodeGenFunction::EmitDynamicCast(llvm::Value *Value,
                                                const CXXDynamicCastExpr *DCE) {
    QualType DestTy = DCE->getTypeAsWritten();
  
    if (DCE->isAlwaysNull())
      if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
        return T;
  
    QualType SrcTy = DCE->getSubExpr()->getType();
  
    // C++ [expr.dynamic.cast]p7:
    //   If T is "pointer to cv void," then the result is a pointer to the most
    //   derived object pointed to by v.
    const PointerType *DestPTy = DestTy->getAs<PointerType>();
  
    bool isDynamicCastToVoid;
    QualType SrcRecordTy;
    QualType DestRecordTy;
    if (DestPTy) {
      isDynamicCastToVoid = DestPTy->getPointeeType()->isVoidType();
      SrcRecordTy = SrcTy->castAs<PointerType>()->getPointeeType();
      DestRecordTy = DestPTy->getPointeeType();
    } else {
      isDynamicCastToVoid = false;
      SrcRecordTy = SrcTy;
      DestRecordTy = DestTy->castAs<ReferenceType>()->getPointeeType();
    }
  
    assert(SrcRecordTy->isRecordType() && "source type must be a record type!");
  
    // C++ [expr.dynamic.cast]p4: 
    //   If the value of v is a null pointer value in the pointer case, the result
    //   is the null pointer value of type T.
    bool ShouldNullCheckSrcValue =
        CGM.getCXXABI().shouldDynamicCastCallBeNullChecked(SrcTy->isPointerType(),
                                                           SrcRecordTy);
  
    llvm::BasicBlock *CastNull = nullptr;
    llvm::BasicBlock *CastNotNull = nullptr;
    llvm::BasicBlock *CastEnd = createBasicBlock("dynamic_cast.end");
    
    if (ShouldNullCheckSrcValue) {
      CastNull = createBasicBlock("dynamic_cast.null");
      CastNotNull = createBasicBlock("dynamic_cast.notnull");
  
      llvm::Value *IsNull = Builder.CreateIsNull(Value);
      Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
      EmitBlock(CastNotNull);
    }
  
    if (isDynamicCastToVoid) {
      Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, Value, SrcRecordTy,
                                                    DestTy);
    } else {
      assert(DestRecordTy->isRecordType() &&
             "destination type must be a record type!");
      Value = CGM.getCXXABI().EmitDynamicCastCall(*this, Value, SrcRecordTy,
                                                  DestTy, DestRecordTy, CastEnd);
    }
  
    if (ShouldNullCheckSrcValue) {
      EmitBranch(CastEnd);
  
      EmitBlock(CastNull);
      EmitBranch(CastEnd);
    }
  
    EmitBlock(CastEnd);
  
    if (ShouldNullCheckSrcValue) {
      llvm::PHINode *PHI = Builder.CreatePHI(Value->getType(), 2);
      PHI->addIncoming(Value, CastNotNull);
      PHI->addIncoming(llvm::Constant::getNullValue(Value->getType()), CastNull);
  
      Value = PHI;
    }
  
    return Value;
  }
  
  void CodeGenFunction::EmitLambdaExpr(const LambdaExpr *E, AggValueSlot Slot) {
    RunCleanupsScope Scope(*this);
    LValue SlotLV =
        MakeAddrLValue(Slot.getAddr(), E->getType(), Slot.getAlignment());
  
    CXXRecordDecl::field_iterator CurField = E->getLambdaClass()->field_begin();
    for (LambdaExpr::capture_init_iterator i = E->capture_init_begin(),
                                           e = E->capture_init_end();
         i != e; ++i, ++CurField) {
      // Emit initialization
      LValue LV = EmitLValueForFieldInitialization(SlotLV, *CurField);
      if (CurField->hasCapturedVLAType()) {
        auto VAT = CurField->getCapturedVLAType();
        EmitStoreThroughLValue(RValue::get(VLASizeMap[VAT->getSizeExpr()]), LV);
      } else {
        ArrayRef<VarDecl *> ArrayIndexes;
        if (CurField->getType()->isArrayType())
          ArrayIndexes = E->getCaptureInitIndexVars(i);
        EmitInitializerForField(*CurField, LV, *i, ArrayIndexes);
      }
    }
  }
  