text: //===--- CGExprCXX.cpp - Emit LLVM Code for C++ expressions ---------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This contains code dealing with code generation of C++ expressions
  //
  //===----------------------------------------------------------------------===//
  
  #include "CodeGenFunction.h"
  #include "CGCUDARuntime.h"
  #include "CGCXXABI.h"
  #include "CGDebugInfo.h"
  #include "CGObjCRuntime.h"
  #include "ConstantEmitter.h"
  #include "clang/Basic/CodeGenOptions.h"
  #include "clang/CodeGen/CGFunctionInfo.h"
  #include "llvm/IR/CallSite.h"
  #include "llvm/IR/Intrinsics.h"
  
  using namespace clang;
  using namespace CodeGen;
  
  namespace {
  struct MemberCallInfo {
    RequiredArgs ReqArgs;
    // Number of prefix arguments for the call. Ignores the `this` pointer.
    unsigned PrefixSize;
  };
  }
  
  static MemberCallInfo
  commonEmitCXXMemberOrOperatorCall(CodeGenFunction &CGF, const CXXMethodDecl *MD,
                                    llvm::Value *This, llvm::Value *ImplicitParam,
                                    QualType ImplicitParamTy, const CallExpr *CE,
                                    CallArgList &Args, CallArgList *RtlArgs) {
    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!");
    ASTContext &C = CGF.getContext();
  
    // Push the this ptr.
    const CXXRecordDecl *RD =
        CGF.CGM.getCXXABI().getThisArgumentTypeForMethod(MD);
    Args.add(RValue::get(This),
             RD ? C.getPointerType(C.getTypeDeclType(RD)) : C.VoidPtrTy);
  
    // 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(), MD);
    unsigned PrefixSize = Args.size() - 1;
  
    // And the rest of the call args.
    if (RtlArgs) {
      // Special case: if the caller emitted the arguments right-to-left already
      // (prior to emitting the *this argument), we're done. This happens for
      // assignment operators.
      Args.addFrom(*RtlArgs);
    } else if (CE) {
      // Special case: skip first argument of CXXOperatorCall (it is "this").
      unsigned ArgsToSkip = isa<CXXOperatorCallExpr>(CE) ? 1 : 0;
      CGF.EmitCallArgs(Args, FPT, drop_begin(CE->arguments(), ArgsToSkip),
                       CE->getDirectCallee());
    } else {
      assert(
          FPT->getNumParams() == 0 &&
          "No CallExpr specified for function with non-zero number of arguments");
    }
    return {required, PrefixSize};
  }
  
  RValue CodeGenFunction::EmitCXXMemberOrOperatorCall(
      const CXXMethodDecl *MD, const CGCallee &Callee,
      ReturnValueSlot ReturnValue,
      llvm::Value *This, llvm::Value *ImplicitParam, QualType ImplicitParamTy,
      const CallExpr *CE, CallArgList *RtlArgs) {
    const FunctionProtoType *FPT = MD->getType()->castAs<FunctionProtoType>();
    CallArgList Args;
    MemberCallInfo CallInfo = commonEmitCXXMemberOrOperatorCall(
        *this, MD, This, ImplicitParam, ImplicitParamTy, CE, Args, RtlArgs);
    auto &FnInfo = CGM.getTypes().arrangeCXXMethodCall(
        Args, FPT, CallInfo.ReqArgs, CallInfo.PrefixSize);
    return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr,
                    CE ? CE->getExprLoc() : SourceLocation());
  }
  
  RValue CodeGenFunction::EmitCXXDestructorCall(
      const CXXDestructorDecl *DD, const CGCallee &Callee, llvm::Value *This,
      llvm::Value *ImplicitParam, QualType ImplicitParamTy, const CallExpr *CE,
      StructorType Type) {
    CallArgList Args;
    commonEmitCXXMemberOrOperatorCall(*this, DD, This, ImplicitParam,
                                      ImplicitParamTy, CE, Args, nullptr);
    return EmitCall(CGM.getTypes().arrangeCXXStructorDeclaration(DD, Type),
                    Callee, ReturnValueSlot(), Args);
  }
  
  RValue CodeGenFunction::EmitCXXPseudoDestructorExpr(
                                              const CXXPseudoDestructorExpr *E) {
    QualType DestroyedType = E->getDestroyedType();
    if (DestroyedType.hasStrongOrWeakObjCLifetime()) {
      // Automatic Reference Counting:
      //   If the pseudo-expression names a retainable object with weak or
      //   strong lifetime, the object shall be released.
      Expr *BaseExpr = E->getBase();
      Address BaseValue = Address::invalid();
      Qualifiers BaseQuals;
  
      // If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
      if (E->isArrow()) {
        BaseValue = EmitPointerWithAlignment(BaseExpr);
        const PointerType *PTy = BaseExpr->getType()->getAs<PointerType>();
        BaseQuals = PTy->getPointeeType().getQualifiers();
      } else {
        LValue BaseLV = EmitLValue(BaseExpr);
        BaseValue = BaseLV.getAddress();
        QualType BaseTy = BaseExpr->getType();
        BaseQuals = BaseTy.getQualifiers();
      }
  
      switch (DestroyedType.getObjCLifetime()) {
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
      case Qualifiers::OCL_Autoreleasing:
        break;
  
      case Qualifiers::OCL_Strong:
        EmitARCRelease(Builder.CreateLoad(BaseValue,
                          DestroyedType.isVolatileQualified()),
                       ARCPreciseLifetime);
        break;
  
      case Qualifiers::OCL_Weak:
        EmitARCDestroyWeak(BaseValue);
        break;
      }
    } else {
      // C++ [expr.pseudo]p1:
      //   The result shall only be used as the operand for the function call
      //   operator (), and the result of such a call has type void. The only
      //   effect is the evaluation of the postfix-expression before the dot or
      //   arrow.
      EmitIgnoredExpr(E->getBase());
    }
  
    return RValue::get(nullptr);
  }
  
  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.
      CGCallee callee =
          CGCallee::forDirect(CGM.GetAddrOfFunction(MD), GlobalDecl(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));
  
    // Compute the object pointer.
    bool CanUseVirtualCall = MD->isVirtual() && !HasQualifier;
  
    const CXXMethodDecl *DevirtualizedMethod = nullptr;
    if (CanUseVirtualCall &&
        MD->getDevirtualizedMethod(Base, getLangOpts().AppleKext)) {
      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;
      }
    }
  
    // C++17 demands that we evaluate the RHS of a (possibly-compound) assignment
    // operator before the LHS.
    CallArgList RtlArgStorage;
    CallArgList *RtlArgs = nullptr;
    if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(CE)) {
      if (OCE->isAssignmentOp()) {
        RtlArgs = &RtlArgStorage;
        EmitCallArgs(*RtlArgs, MD->getType()->castAs<FunctionProtoType>(),
                     drop_begin(CE->arguments(), 1), CE->getDirectCallee(),
                     /*ParamsToSkip*/0, EvaluationOrder::ForceRightToLeft);
      }
    }
  
    LValue This;
    if (IsArrow) {
      LValueBaseInfo BaseInfo;
      TBAAAccessInfo TBAAInfo;
      Address ThisValue = EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
      This = MakeAddrLValue(ThisValue, Base->getType(), BaseInfo, TBAAInfo);
    } else {
      This = EmitLValue(Base);
    }
  
  
    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.
          LValue RHS = isa<CXXOperatorCallExpr>(CE)
                           ? MakeNaturalAlignAddrLValue(
                                 (*RtlArgs)[0].getRValue(*this).getScalarVal(),
                                 (*(CE->arg_begin() + 1))->getType())
                           : EmitLValue(*CE->arg_begin());
          EmitAggregateAssign(This, RHS, CE->getType());
          return RValue::get(This.getPointer());
        }
  
        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");
          const Expr *Arg = *CE->arg_begin();
          LValue RHS = EmitLValue(Arg);
          LValue Dest = MakeAddrLValue(This.getAddress(), Arg->getType());
          // This is the MSVC p->Ctor::Ctor(...) extension. We assume that's
          // constructing a new complete object of type Ctor.
          EmitAggregateCopy(Dest, RHS, Arg->getType(),
                            AggValueSlot::DoesNotOverlap);
          return RValue::get(This.getPointer());
        }
        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++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;
    ASTContext &C = getContext();
    if (CE)
      CallLoc = CE->getExprLoc();
  
    SanitizerSet SkippedChecks;
    if (const auto *CMCE = dyn_cast<CXXMemberCallExpr>(CE)) {
      auto *IOA = CMCE->getImplicitObjectArgument();
      bool IsImplicitObjectCXXThis = IsWrappedCXXThis(IOA);
      if (IsImplicitObjectCXXThis)
        SkippedChecks.set(SanitizerKind::Alignment, true);
      if (IsImplicitObjectCXXThis || isa<DeclRefExpr>(IOA))
        SkippedChecks.set(SanitizerKind::Null, true);
    }
    EmitTypeCheck(
        isa<CXXConstructorDecl>(CalleeDecl) ? CodeGenFunction::TCK_ConstructorCall
                                            : CodeGenFunction::TCK_MemberCall,
        CallLoc, This.getPointer(), C.getRecordType(CalleeDecl->getParent()),
        /*Alignment=*/CharUnits::Zero(), SkippedChecks);
  
    // FIXME: Uses of 'MD' past this point need to be audited. We may need to use
    // 'CalleeDecl' instead.
  
    // 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;
  
    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.getAddress(),
            cast<CXXMemberCallExpr>(CE));
      } else {
        CGCallee Callee;
        if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
          Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
        else if (!DevirtualizedMethod)
          Callee = CGCallee::forDirect(
              CGM.getAddrOfCXXStructor(Dtor, StructorType::Complete, FInfo, Ty),
              GlobalDecl(Dtor, Dtor_Complete));
        else {
          const CXXDestructorDecl *DDtor =
            cast<CXXDestructorDecl>(DevirtualizedMethod);
          Callee = CGCallee::forDirect(
              CGM.GetAddrOfFunction(GlobalDecl(DDtor, Dtor_Complete), Ty),
              GlobalDecl(DDtor, Dtor_Complete));
        }
        EmitCXXMemberOrOperatorCall(
            CalleeDecl, Callee, ReturnValue, This.getPointer(),
            /*ImplicitParam=*/nullptr, QualType(), CE, nullptr);
      }
      return RValue::get(nullptr);
    }
  
    CGCallee Callee;
    if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(MD)) {
      Callee = CGCallee::forDirect(
          CGM.GetAddrOfFunction(GlobalDecl(Ctor, Ctor_Complete), Ty),
          GlobalDecl(Ctor, Ctor_Complete));
    } else if (UseVirtualCall) {
      Callee = CGCallee::forVirtual(CE, MD, This.getAddress(), Ty);
    } else {
      if (SanOpts.has(SanitizerKind::CFINVCall) &&
          MD->getParent()->isDynamicClass()) {
        llvm::Value *VTable;
        const CXXRecordDecl *RD;
        std::tie(VTable, RD) =
            CGM.getCXXABI().LoadVTablePtr(*this, This.getAddress(),
                                          MD->getParent());
        EmitVTablePtrCheckForCall(RD, VTable, CFITCK_NVCall, CE->getBeginLoc());
      }
  
      if (getLangOpts().AppleKext && MD->isVirtual() && HasQualifier)
        Callee = BuildAppleKextVirtualCall(MD, Qualifier, Ty);
      else if (!DevirtualizedMethod)
        Callee =
            CGCallee::forDirect(CGM.GetAddrOfFunction(MD, Ty), GlobalDecl(MD));
      else {
        Callee =
            CGCallee::forDirect(CGM.GetAddrOfFunction(DevirtualizedMethod, Ty),
                                GlobalDecl(DevirtualizedMethod));
      }
    }
  
    if (MD->isVirtual()) {
      Address NewThisAddr =
          CGM.getCXXABI().adjustThisArgumentForVirtualFunctionCall(
              *this, CalleeDecl, This.getAddress(), UseVirtualCall);
      This.setAddress(NewThisAddr);
    }
  
    return EmitCXXMemberOrOperatorCall(
        CalleeDecl, Callee, ReturnValue, This.getPointer(),
        /*ImplicitParam=*/nullptr, QualType(), CE, RtlArgs);
  }
  
  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());
  
    // Emit the 'this' pointer.
    Address This = Address::invalid();
    if (BO->getOpcode() == BO_PtrMemI)
      This = EmitPointerWithAlignment(BaseExpr);
    else
      This = EmitLValue(BaseExpr).getAddress();
  
    EmitTypeCheck(TCK_MemberCall, E->getExprLoc(), This.getPointer(),
                  QualType(MPT->getClass(), 0));
  
    // Get the member function pointer.
    llvm::Value *MemFnPtr = EmitScalarExpr(MemFnExpr);
  
    // Ask the ABI to load the callee.  Note that This is modified.
    llvm::Value *ThisPtrForCall = nullptr;
    CGCallee Callee =
      CGM.getCXXABI().EmitLoadOfMemberFunctionPointer(*this, BO, This,
                                               ThisPtrForCall, MemFnPtr, MPT);
  
    CallArgList Args;
  
    QualType ThisType =
      getContext().getPointerType(getContext().getTagDeclType(RD));
  
    // Push the this ptr.
    Args.add(RValue::get(ThisPtrForCall), ThisType);
  
    RequiredArgs required =
        RequiredArgs::forPrototypePlus(FPT, 1, /*FD=*/nullptr);
  
    // And the rest of the call args
    EmitCallArgs(Args, FPT, E->arguments());
    return EmitCall(CGM.getTypes().arrangeCXXMethodCall(Args, FPT, required,
                                                        /*PrefixSize=*/0),
                    Callee, ReturnValue, Args, nullptr, E->getExprLoc());
  }
  
  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);
  }
  
  static void EmitNullBaseClassInitialization(CodeGenFunction &CGF,
                                              Address DestPtr,
                                              const CXXRecordDecl *Base) {
    if (Base->isEmpty())
      return;
  
    DestPtr = CGF.Builder.CreateElementBitCast(DestPtr, CGF.Int8Ty);
  
    const ASTRecordLayout &Layout = CGF.getContext().getASTRecordLayout(Base);
    CharUnits NVSize = Layout.getNonVirtualSize();
  
    // We cannot simply zero-initialize the entire base sub-object if vbptrs are
    // present, they are initialized by the most derived class before calling the
    // constructor.
    SmallVector<std::pair<CharUnits, CharUnits>, 1> Stores;
    Stores.emplace_back(CharUnits::Zero(), NVSize);
  
    // Each store is split by the existence of a vbptr.
    CharUnits VBPtrWidth = CGF.getPointerSize();
    std::vector<CharUnits> VBPtrOffsets =
        CGF.CGM.getCXXABI().getVBPtrOffsets(Base);
    for (CharUnits VBPtrOffset : VBPtrOffsets) {
      // Stop before we hit any virtual base pointers located in virtual bases.
      if (VBPtrOffset >= NVSize)
        break;
      std::pair<CharUnits, CharUnits> LastStore = Stores.pop_back_val();
      CharUnits LastStoreOffset = LastStore.first;
      CharUnits LastStoreSize = LastStore.second;
  
      CharUnits SplitBeforeOffset = LastStoreOffset;
      CharUnits SplitBeforeSize = VBPtrOffset - SplitBeforeOffset;
      assert(!SplitBeforeSize.isNegative() && "negative store size!");
      if (!SplitBeforeSize.isZero())
        Stores.emplace_back(SplitBeforeOffset, SplitBeforeSize);
  
      CharUnits SplitAfterOffset = VBPtrOffset + VBPtrWidth;
      CharUnits SplitAfterSize = LastStoreSize - SplitAfterOffset;
      assert(!SplitAfterSize.isNegative() && "negative store size!");
      if (!SplitAfterSize.isZero())
        Stores.emplace_back(SplitAfterOffset, SplitAfterSize);
    }
  
    // 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.
    llvm::Constant *NullConstantForBase = CGF.CGM.EmitNullConstantForBase(Base);
    if (!NullConstantForBase->isNullValue()) {
      llvm::GlobalVariable *NullVariable = new llvm::GlobalVariable(
          CGF.CGM.getModule(), NullConstantForBase->getType(),
          /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage,
          NullConstantForBase, Twine());
  
      CharUnits Align = std::max(Layout.getNonVirtualAlignment(),
                                 DestPtr.getAlignment());
      NullVariable->setAlignment(Align.getQuantity());
  
      Address SrcPtr = Address(CGF.EmitCastToVoidPtr(NullVariable), Align);
  
      // Get and call the appropriate llvm.memcpy overload.
      for (std::pair<CharUnits, CharUnits> Store : Stores) {
        CharUnits StoreOffset = Store.first;
        CharUnits StoreSize = Store.second;
        llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
        CGF.Builder.CreateMemCpy(
            CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
            CGF.Builder.CreateConstInBoundsByteGEP(SrcPtr, StoreOffset),
            StoreSizeVal);
      }
  
    // 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.
    } else {
      for (std::pair<CharUnits, CharUnits> Store : Stores) {
        CharUnits StoreOffset = Store.first;
        CharUnits StoreSize = Store.second;
        llvm::Value *StoreSizeVal = CGF.CGM.getSize(StoreSize);
        CGF.Builder.CreateMemSet(
            CGF.Builder.CreateConstInBoundsByteGEP(DestPtr, StoreOffset),
            CGF.Builder.getInt8(0), StoreSizeVal);
      }
    }
  }
  
  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.getAddress(), E->getType());
        break;
      case CXXConstructExpr::CK_VirtualBase:
      case CXXConstructExpr::CK_NonVirtualBase:
        EmitNullBaseClassInitialization(*this, Dest.getAddress(),
                                        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 ArrayType *arrayType
          = getContext().getAsArrayType(E->getType())) {
      EmitCXXAggrConstructorCall(CD, arrayType, Dest.getAddress(), E,
                                 Dest.isSanitizerChecked());
    } 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;
        LLVM_FALLTHROUGH;
  
       case CXXConstructExpr::CK_NonVirtualBase:
        Type = Ctor_Base;
      }
  
      // Call the constructor.
      EmitCXXConstructorCall(CD, Type, ForVirtualBase, Delegating,
                             Dest.getAddress(), E, Dest.mayOverlap(),
                             Dest.isSanitizerChecked());
    }
  }
  
  void CodeGenFunction::EmitSynthesizedCXXCopyCtor(Address Dest, Address 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 =
      ConstantEmitter(CGF).tryEmitAbstract(e->getArraySize(), e->getType());
    if (!numElements)
      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, Address NewPtr,
                                      AggValueSlot::Overlap_t MayOverlap) {
    // FIXME: Refactor with EmitExprAsInit.
    switch (CGF.getEvaluationKind(AllocType)) {
    case TEK_Scalar:
      CGF.EmitScalarInit(Init, nullptr,
                         CGF.MakeAddrLValue(NewPtr, AllocType), false);
      return;
    case TEK_Complex:
      CGF.EmitComplexExprIntoLValue(Init, CGF.MakeAddrLValue(NewPtr, AllocType),
                                    /*isInit*/ true);
      return;
    case TEK_Aggregate: {
      AggValueSlot Slot
        = AggValueSlot::forAddr(NewPtr, AllocType.getQualifiers(),
                                AggValueSlot::IsDestructed,
                                AggValueSlot::DoesNotNeedGCBarriers,
                                AggValueSlot::IsNotAliased,
                                MayOverlap, AggValueSlot::IsNotZeroed,
                                AggValueSlot::IsSanitizerChecked);
      CGF.EmitAggExpr(Init, Slot);
      return;
    }
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  void CodeGenFunction::EmitNewArrayInitializer(
      const CXXNewExpr *E, QualType ElementType, llvm::Type *ElementTy,
      Address 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;
  
    Address CurPtr = BeginPtr;
  
    unsigned InitListElements = 0;
  
    const Expr *Init = E->getInitializer();
    Address EndOfInit = Address::invalid();
    QualType::DestructionKind DtorKind = ElementType.isDestructedType();
    EHScopeStack::stable_iterator Cleanup;
    llvm::Instruction *CleanupDominator = nullptr;
  
    CharUnits ElementSize = getContext().getTypeSizeInChars(ElementType);
    CharUnits ElementAlign =
      BeginPtr.getAlignment().alignmentOfArrayElement(ElementSize);
  
    // 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.
      Builder.CreateMemSet(CurPtr, Builder.getInt8(0), RemainingSize, false);
      return true;
    };
  
    // If the initializer is an initializer list, first do the explicit elements.
    if (const InitListExpr *ILE = dyn_cast<InitListExpr>(Init)) {
      // Initializing from a (braced) string literal is a special case; the init
      // list element does not initialize a (single) array element.
      if (ILE->isStringLiteralInit()) {
        // Initialize the initial portion of length equal to that of the string
        // literal. The allocation must be for at least this much; we emitted a
        // check for that earlier.
        AggValueSlot Slot =
            AggValueSlot::forAddr(CurPtr, ElementType.getQualifiers(),
                                  AggValueSlot::IsDestructed,
                                  AggValueSlot::DoesNotNeedGCBarriers,
                                  AggValueSlot::IsNotAliased,
                                  AggValueSlot::DoesNotOverlap,
                                  AggValueSlot::IsNotZeroed,
                                  AggValueSlot::IsSanitizerChecked);
        EmitAggExpr(ILE->getInit(0), Slot);
  
        // Move past these elements.
        InitListElements =
            cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
                ->getSize().getZExtValue();
        CurPtr =
            Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
                                              Builder.getSize(InitListElements),
                                              "string.init.end"),
                    CurPtr.getAlignment().alignmentAtOffset(InitListElements *
                                                            ElementSize));
  
        // Zero out the rest, if any remain.
        llvm::ConstantInt *ConstNum = dyn_cast<llvm::ConstantInt>(NumElements);
        if (!ConstNum || !ConstNum->equalsInt(InitListElements)) {
          bool OK = TryMemsetInitialization();
          (void)OK;
          assert(OK && "couldn't memset character type?");
        }
        return;
      }
  
      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())) {
        ElementTy = ConvertTypeForMem(AllocType);
        CurPtr = Builder.CreateElementBitCast(CurPtr, ElementTy);
        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(), getPointerAlign(),
                                     "array.init.end");
        CleanupDominator = Builder.CreateStore(BeginPtr.getPointer(), EndOfInit);
        pushIrregularPartialArrayCleanup(BeginPtr.getPointer(), EndOfInit,
                                         ElementType, ElementAlign,
                                         getDestroyer(DtorKind));
        Cleanup = EHStack.stable_begin();
      }
  
      CharUnits StartAlign = CurPtr.getAlignment();
      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.isValid()) {
          auto FinishedPtr =
            Builder.CreateBitCast(CurPtr.getPointer(), BeginPtr.getType());
          Builder.CreateStore(FinishedPtr, 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,
                                AggValueSlot::DoesNotOverlap);
        CurPtr = Address(Builder.CreateInBoundsGEP(CurPtr.getPointer(),
                                                   Builder.getSize(1),
                                                   "array.exp.next"),
                         StartAlign.alignmentAtOffset((i + 1) * ElementSize));
      }
  
      // 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());
    }
  
    // 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.isValid())
        Builder.CreateStore(CurPtr.getPointer(), 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,
                                 /*NewPointerIsChecked*/true,
                                 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 NumElements = 0;
          if (auto *CXXRD = dyn_cast<CXXRecordDecl>(RType->getDecl()))
            NumElements = CXXRD->getNumBases();
          for (auto *Field : RType->getDecl()->fields())
            if (!Field->isUnnamedBitfield())
              ++NumElements;
          // FIXME: Recurse into nested InitListExprs.
          if (ILE->getNumInits() == NumElements)
            for (unsigned i = 0, e = ILE->getNumInits(); i != e; ++i)
              if (!isa<ImplicitValueInitExpr>(ILE->getInit(i)))
                --NumElements;
          if (ILE->getNumInits() == NumElements && 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.getPointer(), 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.getPointer(), 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.getPointer(), EntryBB);
  
    CurPtr = Address(CurPtrPhi, ElementAlign);
  
    // Store the new Cleanup position for irregular Cleanups.
    if (EndOfInit.isValid())
      Builder.CreateStore(CurPtr.getPointer(), EndOfInit);
  
    // Enter a partial-destruction Cleanup if necessary.
    if (!CleanupDominator && needsEHCleanup(DtorKind)) {
      pushRegularPartialArrayCleanup(BeginPtr.getPointer(), CurPtr.getPointer(),
                                     ElementType, ElementAlign,
                                     getDestroyer(DtorKind));
      Cleanup = EHStack.stable_begin();
      CleanupDominator = Builder.CreateUnreachable();
    }
  
    // Emit the initializer into this element.
    StoreAnyExprIntoOneUnit(*this, Init, Init->getType(), CurPtr,
                            AggValueSlot::DoesNotOverlap);
  
    // 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.getPointer(), 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,
                                 Address 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,
                              AggValueSlot::DoesNotOverlap);
  }
  
  /// 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 *CalleeDecl,
                                  const FunctionProtoType *CalleeType,
                                  const CallArgList &Args) {
    llvm::Instruction *CallOrInvoke;
    llvm::Constant *CalleePtr = CGF.CGM.GetAddrOfFunction(CalleeDecl);
    CGCallee Callee = CGCallee::forDirect(CalleePtr, GlobalDecl(CalleeDecl));
    RValue RV =
        CGF.EmitCall(CGF.CGM.getTypes().arrangeFreeFunctionCall(
                         Args, CalleeType, /*chainCall=*/false),
                     Callee, ReturnValueSlot(), Args, &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>(CalleePtr);
    if (CalleeDecl->isReplaceableGlobalAllocationFunction() &&
        Fn && Fn->hasFnAttribute(llvm::Attribute::NoBuiltin)) {
      // FIXME: Add addAttribute to CallSite.
      if (llvm::CallInst *CI = dyn_cast<llvm::CallInst>(CallOrInvoke))
        CI->addAttribute(llvm::AttributeList::FunctionIndex,
                         llvm::Attribute::Builtin);
      else if (llvm::InvokeInst *II = dyn_cast<llvm::InvokeInst>(CallOrInvoke))
        II->addAttribute(llvm::AttributeList::FunctionIndex,
                         llvm::Attribute::Builtin);
      else
        llvm_unreachable("unexpected kind of call instruction");
    }
  
    return RV;
  }
  
  RValue CodeGenFunction::EmitBuiltinNewDeleteCall(const FunctionProtoType *Type,
                                                   const CallExpr *TheCall,
                                                   bool IsDelete) {
    CallArgList Args;
    EmitCallArgs(Args, Type->getParamTypes(), TheCall->arguments());
    // 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, FD, Type, Args);
    llvm_unreachable("predeclared global operator new/delete is missing");
  }
  
  namespace {
  /// The parameters to pass to a usual operator delete.
  struct UsualDeleteParams {
    bool DestroyingDelete = false;
    bool Size = false;
    bool Alignment = false;
  };
  }
  
  static UsualDeleteParams getUsualDeleteParams(const FunctionDecl *FD) {
    UsualDeleteParams Params;
  
    const FunctionProtoType *FPT = FD->getType()->castAs<FunctionProtoType>();
    auto AI = FPT->param_type_begin(), AE = FPT->param_type_end();
  
    // The first argument is always a void*.
    ++AI;
  
    // The next parameter may be a std::destroying_delete_t.
    if (FD->isDestroyingOperatorDelete()) {
      Params.DestroyingDelete = true;
      assert(AI != AE);
      ++AI;
    }
  
    // Figure out what other parameters we should be implicitly passing.
    if (AI != AE && (*AI)->isIntegerType()) {
      Params.Size = true;
      ++AI;
    }
  
    if (AI != AE && (*AI)->isAlignValT()) {
      Params.Alignment = true;
      ++AI;
    }
  
    assert(AI == AE && "unexpected usual deallocation function parameter");
    return Params;
  }
  
  namespace {
    /// A cleanup to call the given 'operator delete' function upon abnormal
    /// exit from a new expression. Templated on a traits type that deals with
    /// ensuring that the arguments dominate the cleanup if necessary.
    template<typename Traits>
    class CallDeleteDuringNew final : public EHScopeStack::Cleanup {
      /// Type used to hold llvm::Value*s.
      typedef typename Traits::ValueTy ValueTy;
      /// Type used to hold RValues.
      typedef typename Traits::RValueTy RValueTy;
      struct PlacementArg {
        RValueTy ArgValue;
        QualType ArgType;
      };
  
      unsigned NumPlacementArgs : 31;
      unsigned PassAlignmentToPlacementDelete : 1;
      const FunctionDecl *OperatorDelete;
      ValueTy Ptr;
      ValueTy AllocSize;
      CharUnits AllocAlign;
  
      PlacementArg *getPlacementArgs() {
        return reinterpret_cast<PlacementArg *>(this + 1);
      }
  
    public:
      static size_t getExtraSize(size_t NumPlacementArgs) {
        return NumPlacementArgs * sizeof(PlacementArg);
      }
  
      CallDeleteDuringNew(size_t NumPlacementArgs,
                          const FunctionDecl *OperatorDelete, ValueTy Ptr,
                          ValueTy AllocSize, bool PassAlignmentToPlacementDelete,
                          CharUnits AllocAlign)
        : NumPlacementArgs(NumPlacementArgs),
          PassAlignmentToPlacementDelete(PassAlignmentToPlacementDelete),
          OperatorDelete(OperatorDelete), Ptr(Ptr), AllocSize(AllocSize),
          AllocAlign(AllocAlign) {}
  
      void setPlacementArg(unsigned I, RValueTy Arg, QualType Type) {
        assert(I < NumPlacementArgs && "index out of range");
        getPlacementArgs()[I] = {Arg, Type};
      }
  
      void Emit(CodeGenFunction &CGF, Flags flags) override {
        const FunctionProtoType *FPT =
            OperatorDelete->getType()->getAs<FunctionProtoType>();
        CallArgList DeleteArgs;
  
        // The first argument is always a void* (or C* for a destroying operator
        // delete for class type C).
        DeleteArgs.add(Traits::get(CGF, Ptr), FPT->getParamType(0));
  
        // Figure out what other parameters we should be implicitly passing.
        UsualDeleteParams Params;
        if (NumPlacementArgs) {
          // A placement deallocation function is implicitly passed an alignment
          // if the placement allocation function was, but is never passed a size.
          Params.Alignment = PassAlignmentToPlacementDelete;
        } else {
          // For a non-placement new-expression, 'operator delete' can take a
          // size and/or an alignment if it has the right parameters.
          Params = getUsualDeleteParams(OperatorDelete);
        }
  
        assert(!Params.DestroyingDelete &&
               "should not call destroying delete in a new-expression");
  
        // The second argument can be a std::size_t (for non-placement delete).
        if (Params.Size)
          DeleteArgs.add(Traits::get(CGF, AllocSize),
                         CGF.getContext().getSizeType());
  
        // The next (second or third) argument can be a std::align_val_t, which
        // is an enum whose underlying type is std::size_t.
        // FIXME: Use the right type as the parameter type. Note that in a call
        // to operator delete(size_t, ...), we may not have it available.
        if (Params.Alignment)
          DeleteArgs.add(RValue::get(llvm::ConstantInt::get(
                             CGF.SizeTy, AllocAlign.getQuantity())),
                         CGF.getContext().getSizeType());
  
        // Pass the rest of the arguments, which must match exactly.
        for (unsigned I = 0; I != NumPlacementArgs; ++I) {
          auto Arg = getPlacementArgs()[I];
          DeleteArgs.add(Traits::get(CGF, Arg.ArgValue), Arg.ArgType);
        }
  
        // 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,
                                    Address NewPtr,
                                    llvm::Value *AllocSize,
                                    CharUnits AllocAlign,
                                    const CallArgList &NewArgs) {
    unsigned NumNonPlacementArgs = E->passAlignment() ? 2 : 1;
  
    // 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()) {
      struct DirectCleanupTraits {
        typedef llvm::Value *ValueTy;
        typedef RValue RValueTy;
        static RValue get(CodeGenFunction &, ValueTy V) { return RValue::get(V); }
        static RValue get(CodeGenFunction &, RValueTy V) { return V; }
      };
  
      typedef CallDeleteDuringNew<DirectCleanupTraits> DirectCleanup;
  
      DirectCleanup *Cleanup = CGF.EHStack
        .pushCleanupWithExtra<DirectCleanup>(EHCleanup,
                                             E->getNumPlacementArgs(),
                                             E->getOperatorDelete(),
                                             NewPtr.getPointer(),
                                             AllocSize,
                                             E->passAlignment(),
                                             AllocAlign);
      for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
        auto &Arg = NewArgs[I + NumNonPlacementArgs];
        Cleanup->setPlacementArg(I, Arg.getRValue(CGF), Arg.Ty);
      }
  
      return;
    }
  
    // Otherwise, we need to save all this stuff.
    DominatingValue<RValue>::saved_type SavedNewPtr =
      DominatingValue<RValue>::save(CGF, RValue::get(NewPtr.getPointer()));
    DominatingValue<RValue>::saved_type SavedAllocSize =
      DominatingValue<RValue>::save(CGF, RValue::get(AllocSize));
  
    struct ConditionalCleanupTraits {
      typedef DominatingValue<RValue>::saved_type ValueTy;
      typedef DominatingValue<RValue>::saved_type RValueTy;
      static RValue get(CodeGenFunction &CGF, ValueTy V) {
        return V.restore(CGF);
      }
    };
    typedef CallDeleteDuringNew<ConditionalCleanupTraits> ConditionalCleanup;
  
    ConditionalCleanup *Cleanup = CGF.EHStack
      .pushCleanupWithExtra<ConditionalCleanup>(EHCleanup,
                                                E->getNumPlacementArgs(),
                                                E->getOperatorDelete(),
                                                SavedNewPtr,
                                                SavedAllocSize,
                                                E->passAlignment(),
                                                AllocAlign);
    for (unsigned I = 0, N = E->getNumPlacementArgs(); I != N; ++I) {
      auto &Arg = NewArgs[I + NumNonPlacementArgs];
      Cleanup->setPlacementArg(
          I, DominatingValue<RValue>::save(CGF, Arg.getRValue(CGF)), Arg.Ty);
    }
  
    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();
  
    // If there is a brace-initializer, cannot allocate fewer elements than inits.
    unsigned minElements = 0;
    if (E->isArray() && E->hasInitializer()) {
      const InitListExpr *ILE = dyn_cast<InitListExpr>(E->getInitializer());
      if (ILE && ILE->isStringLiteralInit())
        minElements =
            cast<ConstantArrayType>(ILE->getType()->getAsArrayTypeUnsafe())
                ->getSize().getZExtValue();
      else if (ILE)
        minElements = ILE->getNumInits();
    }
  
    llvm::Value *numElements = nullptr;
    llvm::Value *allocSizeWithoutCookie = nullptr;
    llvm::Value *allocSize =
      EmitCXXNewAllocSize(*this, E, minElements, numElements,
                          allocSizeWithoutCookie);
    CharUnits allocAlign = getContext().getTypeAlignInChars(allocType);
  
    // Emit the allocation call.  If the allocator is a global placement
    // operator, just "inline" it directly.
    Address allocation = Address::invalid();
    CallArgList allocatorArgs;
    if (allocator->isReservedGlobalPlacementOperator()) {
      assert(E->getNumPlacementArgs() == 1);
      const Expr *arg = *E->placement_arguments().begin();
  
      LValueBaseInfo BaseInfo;
      allocation = EmitPointerWithAlignment(arg, &BaseInfo);
  
      // The pointer expression will, in many cases, be an opaque void*.
      // In these cases, discard the computed alignment and use the
      // formal alignment of the allocated type.
      if (BaseInfo.getAlignmentSource() != AlignmentSource::Decl)
        allocation = Address(allocation.getPointer(), allocAlign);
  
      // Set up allocatorArgs for the call to operator delete if it's not
      // the reserved global operator.
      if (E->getOperatorDelete() &&
          !E->getOperatorDelete()->isReservedGlobalPlacementOperator()) {
        allocatorArgs.add(RValue::get(allocSize), getContext().getSizeType());
        allocatorArgs.add(RValue::get(allocation.getPointer()), arg->getType());
      }
  
    } else {
      const FunctionProtoType *allocatorType =
        allocator->getType()->castAs<FunctionProtoType>();
      unsigned ParamsToSkip = 0;
  
      // The allocation size is the first argument.
      QualType sizeType = getContext().getSizeType();
      allocatorArgs.add(RValue::get(allocSize), sizeType);
      ++ParamsToSkip;
  
      if (allocSize != allocSizeWithoutCookie) {
        CharUnits cookieAlign = getSizeAlign(); // FIXME: Ask the ABI.
        allocAlign = std::max(allocAlign, cookieAlign);
      }
  
      // The allocation alignment may be passed as the second argument.
      if (E->passAlignment()) {
        QualType AlignValT = sizeType;
        if (allocatorType->getNumParams() > 1) {
          AlignValT = allocatorType->getParamType(1);
          assert(getContext().hasSameUnqualifiedType(
                     AlignValT->castAs<EnumType>()->getDecl()->getIntegerType(),
                     sizeType) &&
                 "wrong type for alignment parameter");
          ++ParamsToSkip;
        } else {
          // Corner case, passing alignment to 'operator new(size_t, ...)'.
          assert(allocator->isVariadic() && "can't pass alignment to allocator");
        }
        allocatorArgs.add(
            RValue::get(llvm::ConstantInt::get(SizeTy, allocAlign.getQuantity())),
            AlignValT);
      }
  
      // FIXME: Why do we not pass a CalleeDecl here?
      EmitCallArgs(allocatorArgs, allocatorType, E->placement_arguments(),
                   /*AC*/AbstractCallee(), /*ParamsToSkip*/ParamsToSkip);
  
      RValue RV =
        EmitNewDeleteCall(*this, allocator, allocatorType, allocatorArgs);
  
      // If this was a call to a global replaceable allocation function that does
      // not take an alignment argument, the allocator is known to produce
      // storage that's suitably aligned for any object that fits, up to a known
      // threshold. Otherwise assume it's suitably aligned for the allocated type.
      CharUnits allocationAlign = allocAlign;
      if (!E->passAlignment() &&
          allocator->isReplaceableGlobalAllocationFunction()) {
        unsigned AllocatorAlign = llvm::PowerOf2Floor(std::min<uint64_t>(
            Target.getNewAlign(), getContext().getTypeSize(allocType)));
        allocationAlign = std::max(
            allocationAlign, getContext().toCharUnitsFromBits(AllocatorAlign));
      }
  
      allocation = Address(RV.getScalarVal(), allocationAlign);
    }
  
    // 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 will be running sanitizers on the initialization.
    bool nullCheck = E->shouldNullCheckAllocation() &&
                     (!allocType.isPODType(getContext()) || E->hasInitializer() ||
                      sanitizePerformTypeCheck());
  
    llvm::BasicBlock *nullCheckBB = nullptr;
    llvm::BasicBlock *contBB = nullptr;
  
    // 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.getPointer(), "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, allocAlign,
                            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);
    Address result = Builder.CreateElementBitCast(allocation, elementTy);
  
    // Passing pointer through launder.invariant.group to avoid propagation of
    // vptrs information which may be included in previous type.
    // To not break LTO with different optimizations levels, we do it regardless
    // of optimization level.
    if (CGM.getCodeGenOpts().StrictVTablePointers &&
        allocator->isReservedGlobalPlacementOperator())
      result = Address(Builder.CreateLaunderInvariantGroup(result.getPointer()),
                       result.getAlignment());
  
    // Emit sanitizer checks for pointer value now, so that in the case of an
    // array it was checked only once and not at each constructor call. We may
    // have already checked that the pointer is non-null.
    // FIXME: If we have an array cookie and a potentially-throwing allocator,
    // we'll null check the wrong pointer here.
    SanitizerSet SkippedChecks;
    SkippedChecks.set(SanitizerKind::Null, nullCheck);
    EmitTypeCheck(CodeGenFunction::TCK_ConstructorCall,
                  E->getAllocatedTypeSourceInfo()->getTypeLoc().getBeginLoc(),
                  result.getPointer(), allocType, result.getAlignment(),
                  SkippedChecks, numElements);
  
    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();
    }
  
    llvm::Value *resultPtr = result.getPointer();
    if (nullCheck) {
      conditional.end(*this);
  
      llvm::BasicBlock *notNullBB = Builder.GetInsertBlock();
      EmitBlock(contBB);
  
      llvm::PHINode *PHI = Builder.CreatePHI(resultPtr->getType(), 2);
      PHI->addIncoming(resultPtr, notNullBB);
      PHI->addIncoming(llvm::Constant::getNullValue(resultPtr->getType()),
                       nullCheckBB);
  
      resultPtr = PHI;
    }
  
    return resultPtr;
  }
  
  void CodeGenFunction::EmitDeleteCall(const FunctionDecl *DeleteFD,
                                       llvm::Value *Ptr, QualType DeleteTy,
                                       llvm::Value *NumElements,
                                       CharUnits CookieSize) {
    assert((!NumElements && CookieSize.isZero()) ||
           DeleteFD->getOverloadedOperator() == OO_Array_Delete);
  
    const FunctionProtoType *DeleteFTy =
      DeleteFD->getType()->getAs<FunctionProtoType>();
  
    CallArgList DeleteArgs;
  
    auto Params = getUsualDeleteParams(DeleteFD);
    auto ParamTypeIt = DeleteFTy->param_type_begin();
  
    // Pass the pointer itself.
    QualType ArgTy = *ParamTypeIt++;
    llvm::Value *DeletePtr = Builder.CreateBitCast(Ptr, ConvertType(ArgTy));
    DeleteArgs.add(RValue::get(DeletePtr), ArgTy);
  
    // Pass the std::destroying_delete tag if present.
    if (Params.DestroyingDelete) {
      QualType DDTag = *ParamTypeIt++;
      // Just pass an 'undef'. We expect the tag type to be an empty struct.
      auto *V = llvm::UndefValue::get(getTypes().ConvertType(DDTag));
      DeleteArgs.add(RValue::get(V), DDTag);
    }
  
    // Pass the size if the delete function has a size_t parameter.
    if (Params.Size) {
      QualType SizeType = *ParamTypeIt++;
      CharUnits DeleteTypeSize = getContext().getTypeSizeInChars(DeleteTy);
      llvm::Value *Size = llvm::ConstantInt::get(ConvertType(SizeType),
                                                 DeleteTypeSize.getQuantity());
  
      // For array new, multiply by the number of elements.
      if (NumElements)
        Size = Builder.CreateMul(Size, NumElements);
  
      // If there is a cookie, add the cookie size.
      if (!CookieSize.isZero())
        Size = Builder.CreateAdd(
            Size, llvm::ConstantInt::get(SizeTy, CookieSize.getQuantity()));
  
      DeleteArgs.add(RValue::get(Size), SizeType);
    }
  
    // Pass the alignment if the delete function has an align_val_t parameter.
    if (Params.Alignment) {
      QualType AlignValType = *ParamTypeIt++;
      CharUnits DeleteTypeAlign = getContext().toCharUnitsFromBits(
          getContext().getTypeAlignIfKnown(DeleteTy));
      llvm::Value *Align = llvm::ConstantInt::get(ConvertType(AlignValType),
                                                  DeleteTypeAlign.getQuantity());
      DeleteArgs.add(RValue::get(Align), AlignValType);
    }
  
    assert(ParamTypeIt == DeleteFTy->param_type_end() &&
           "unknown parameter to usual delete function");
  
    // Emit the call to delete.
    EmitNewDeleteCall(*this, DeleteFD, DeleteFTy, DeleteArgs);
  }
  
  namespace {
    /// Calls the given 'operator delete' on a single object.
    struct CallObjectDelete final : 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 with a destroying operator
  /// delete. If the element type has a non-virtual destructor, Ptr has already
  /// been converted to the type of the parameter of 'operator delete'. Otherwise
  /// Ptr points to an object of the static type.
  static void EmitDestroyingObjectDelete(CodeGenFunction &CGF,
                                         const CXXDeleteExpr *DE, Address Ptr,
                                         QualType ElementType) {
    auto *Dtor = ElementType->getAsCXXRecordDecl()->getDestructor();
    if (Dtor && Dtor->isVirtual())
      CGF.CGM.getCXXABI().emitVirtualObjectDelete(CGF, DE, Ptr, ElementType,
                                                  Dtor);
    else
      CGF.EmitDeleteCall(DE->getOperatorDelete(), Ptr.getPointer(), ElementType);
  }
  
  /// Emit the code for deleting a single object.
  static void EmitObjectDelete(CodeGenFunction &CGF,
                               const CXXDeleteExpr *DE,
                               Address Ptr,
                               QualType ElementType) {
    // C++11 [expr.delete]p3:
    //   If the static type of the object to be deleted is different from its
    //   dynamic type, the static type shall be a base class of the dynamic type
    //   of the object to be deleted and the static type shall have a virtual
    //   destructor or the behavior is undefined.
    CGF.EmitTypeCheck(CodeGenFunction::TCK_MemberCall,
                      DE->getExprLoc(), Ptr.getPointer(),
                      ElementType);
  
    const FunctionDecl *OperatorDelete = DE->getOperatorDelete();
    assert(!OperatorDelete->isDestroyingOperatorDelete());
  
    // 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.
    CGF.EHStack.pushCleanup<CallObjectDelete>(NormalAndEHCleanup,
                                              Ptr.getPointer(),
                                              OperatorDelete, ElementType);
  
    if (Dtor)
      CGF.EmitCXXDestructorCall(Dtor, Dtor_Complete,
                                /*ForVirtualBase=*/false,
                                /*Delegating=*/false,
                                Ptr);
    else if (auto Lifetime = ElementType.getObjCLifetime()) {
      switch (Lifetime) {
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
      case Qualifiers::OCL_Autoreleasing:
        break;
  
      case Qualifiers::OCL_Strong:
        CGF.EmitARCDestroyStrong(Ptr, 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 final : 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 {
        CGF.EmitDeleteCall(OperatorDelete, Ptr, ElementType, NumElements,
                           CookieSize);
      }
    };
  }
  
  /// Emit the code for deleting an array of objects.
  static void EmitArrayDelete(CodeGenFunction &CGF,
                              const CXXDeleteExpr *E,
                              Address 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!");
  
      CharUnits elementSize = CGF.getContext().getTypeSizeInChars(elementType);
      CharUnits elementAlign =
        deletedPtr.getAlignment().alignmentOfArrayElement(elementSize);
  
      llvm::Value *arrayBegin = deletedPtr.getPointer();
      llvm::Value *arrayEnd =
        CGF.Builder.CreateInBoundsGEP(arrayBegin, 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(arrayBegin, arrayEnd, elementType, elementAlign,
                           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();
    Address Ptr = EmitPointerWithAlignment(Arg);
  
    // Null check the pointer.
    llvm::BasicBlock *DeleteNotNull = createBasicBlock("delete.notnull");
    llvm::BasicBlock *DeleteEnd = createBasicBlock("delete.end");
  
    llvm::Value *IsNull = Builder.CreateIsNull(Ptr.getPointer(), "isnull");
  
    Builder.CreateCondBr(IsNull, DeleteEnd, DeleteNotNull);
    EmitBlock(DeleteNotNull);
  
    QualType DeleteTy = E->getDestroyedType();
  
    // A destroying operator delete overrides the entire operation of the
    // delete expression.
    if (E->getOperatorDelete()->isDestroyingOperatorDelete()) {
      EmitDestroyingObjectDelete(*this, E, Ptr, DeleteTy);
      EmitBlock(DeleteEnd);
      return;
    }
  
    // 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]]*)
    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 = Address(Builder.CreateInBoundsGEP(Ptr.getPointer(), GEP, "del.first"),
                    Ptr.getAlignment());
    }
  
    assert(ConvertTypeForMem(DeleteTy) == Ptr.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.
    Address ThisPtr = CGF.EmitLValue(E).getAddress();
  
    QualType SrcRecordTy = E->getType();
  
    // C++ [class.cdtor]p4:
    //   If the operand of typeid refers to the object under construction or
    //   destruction and the static type of the operand is neither the constructor
    //   or destructor’s class nor one of its bases, the behavior is undefined.
    CGF.EmitTypeCheck(CodeGenFunction::TCK_DynamicOperation, E->getExprLoc(),
                      ThisPtr.getPointer(), SrcRecordTy);
  
    // 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.
    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.getPointer());
      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(Address ThisAddr,
                                                const CXXDynamicCastExpr *DCE) {
    CGM.EmitExplicitCastExprType(DCE, this);
    QualType DestTy = DCE->getTypeAsWritten();
  
    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();
    }
  
    // C++ [class.cdtor]p5:
    //   If the operand of the dynamic_cast refers to the object under
    //   construction or destruction and the static type of the operand is not a
    //   pointer to or object of the constructor or destructor’s own class or one
    //   of its bases, the dynamic_cast results in undefined behavior.
    EmitTypeCheck(TCK_DynamicOperation, DCE->getExprLoc(), ThisAddr.getPointer(),
                  SrcRecordTy);
  
    if (DCE->isAlwaysNull())
      if (llvm::Value *T = EmitDynamicCastToNull(*this, DestTy))
        return T;
  
    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(ThisAddr.getPointer());
      Builder.CreateCondBr(IsNull, CastNull, CastNotNull);
      EmitBlock(CastNotNull);
    }
  
    llvm::Value *Value;
    if (isDynamicCastToVoid) {
      Value = CGM.getCXXABI().EmitDynamicCastToVoid(*this, ThisAddr, SrcRecordTy,
                                                    DestTy);
    } else {
      assert(DestRecordTy->isRecordType() &&
             "destination type must be a record type!");
      Value = CGM.getCXXABI().EmitDynamicCastCall(*this, ThisAddr, SrcRecordTy,
                                                  DestTy, DestRecordTy, CastEnd);
      CastNotNull = Builder.GetInsertBlock();
    }
  
    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;
  }
  