text: //===--- CGExpr.cpp - Emit LLVM Code from 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 to emit Expr nodes as LLVM code.
  //
  //===----------------------------------------------------------------------===//
  
  #include "CGCXXABI.h"
  #include "CGCall.h"
  #include "CGCleanup.h"
  #include "CGDebugInfo.h"
  #include "CGObjCRuntime.h"
  #include "CGOpenMPRuntime.h"
  #include "CGRecordLayout.h"
  #include "CodeGenFunction.h"
  #include "CodeGenModule.h"
  #include "ConstantEmitter.h"
  #include "TargetInfo.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/Attr.h"
  #include "clang/AST/DeclObjC.h"
  #include "clang/AST/NSAPI.h"
  #include "clang/Basic/CodeGenOptions.h"
  #include "llvm/ADT/Hashing.h"
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/IR/DataLayout.h"
  #include "llvm/IR/Intrinsics.h"
  #include "llvm/IR/LLVMContext.h"
  #include "llvm/IR/MDBuilder.h"
  #include "llvm/Support/ConvertUTF.h"
  #include "llvm/Support/MathExtras.h"
  #include "llvm/Support/Path.h"
  #include "llvm/Transforms/Utils/SanitizerStats.h"
  
  #include <string>
  
  using namespace clang;
  using namespace CodeGen;
  
  //===--------------------------------------------------------------------===//
  //                        Miscellaneous Helper Methods
  //===--------------------------------------------------------------------===//
  
  llvm::Value *CodeGenFunction::EmitCastToVoidPtr(llvm::Value *value) {
    unsigned addressSpace =
        cast<llvm::PointerType>(value->getType())->getAddressSpace();
  
    llvm::PointerType *destType = Int8PtrTy;
    if (addressSpace)
      destType = llvm::Type::getInt8PtrTy(getLLVMContext(), addressSpace);
  
    if (value->getType() == destType) return value;
    return Builder.CreateBitCast(value, destType);
  }
  
  /// CreateTempAlloca - This creates a alloca and inserts it into the entry
  /// block.
  Address CodeGenFunction::CreateTempAllocaWithoutCast(llvm::Type *Ty,
                                                       CharUnits Align,
                                                       const Twine &Name,
                                                       llvm::Value *ArraySize) {
    auto Alloca = CreateTempAlloca(Ty, Name, ArraySize);
    Alloca->setAlignment(Align.getQuantity());
    return Address(Alloca, Align);
  }
  
  /// CreateTempAlloca - This creates a alloca and inserts it into the entry
  /// block. The alloca is casted to default address space if necessary.
  Address CodeGenFunction::CreateTempAlloca(llvm::Type *Ty, CharUnits Align,
                                            const Twine &Name,
                                            llvm::Value *ArraySize,
                                            Address *AllocaAddr) {
    auto Alloca = CreateTempAllocaWithoutCast(Ty, Align, Name, ArraySize);
    if (AllocaAddr)
      *AllocaAddr = Alloca;
    llvm::Value *V = Alloca.getPointer();
    // Alloca always returns a pointer in alloca address space, which may
    // be different from the type defined by the language. For example,
    // in C++ the auto variables are in the default address space. Therefore
    // cast alloca to the default address space when necessary.
    if (getASTAllocaAddressSpace() != LangAS::Default) {
      auto DestAddrSpace = getContext().getTargetAddressSpace(LangAS::Default);
      llvm::IRBuilderBase::InsertPointGuard IPG(Builder);
      // When ArraySize is nullptr, alloca is inserted at AllocaInsertPt,
      // otherwise alloca is inserted at the current insertion point of the
      // builder.
      if (!ArraySize)
        Builder.SetInsertPoint(AllocaInsertPt);
      V = getTargetHooks().performAddrSpaceCast(
          *this, V, getASTAllocaAddressSpace(), LangAS::Default,
          Ty->getPointerTo(DestAddrSpace), /*non-null*/ true);
    }
  
    return Address(V, Align);
  }
  
  /// CreateTempAlloca - This creates an alloca and inserts it into the entry
  /// block if \p ArraySize is nullptr, otherwise inserts it at the current
  /// insertion point of the builder.
  llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(llvm::Type *Ty,
                                                      const Twine &Name,
                                                      llvm::Value *ArraySize) {
    if (ArraySize)
      return Builder.CreateAlloca(Ty, ArraySize, Name);
    return new llvm::AllocaInst(Ty, CGM.getDataLayout().getAllocaAddrSpace(),
                                ArraySize, Name, AllocaInsertPt);
  }
  
  /// CreateDefaultAlignTempAlloca - This creates an alloca with the
  /// default alignment of the corresponding LLVM type, which is *not*
  /// guaranteed to be related in any way to the expected alignment of
  /// an AST type that might have been lowered to Ty.
  Address CodeGenFunction::CreateDefaultAlignTempAlloca(llvm::Type *Ty,
                                                        const Twine &Name) {
    CharUnits Align =
      CharUnits::fromQuantity(CGM.getDataLayout().getABITypeAlignment(Ty));
    return CreateTempAlloca(Ty, Align, Name);
  }
  
  void CodeGenFunction::InitTempAlloca(Address Var, llvm::Value *Init) {
    assert(isa<llvm::AllocaInst>(Var.getPointer()));
    auto *Store = new llvm::StoreInst(Init, Var.getPointer());
    Store->setAlignment(Var.getAlignment().getQuantity());
    llvm::BasicBlock *Block = AllocaInsertPt->getParent();
    Block->getInstList().insertAfter(AllocaInsertPt->getIterator(), Store);
  }
  
  Address CodeGenFunction::CreateIRTemp(QualType Ty, const Twine &Name) {
    CharUnits Align = getContext().getTypeAlignInChars(Ty);
    return CreateTempAlloca(ConvertType(Ty), Align, Name);
  }
  
  Address CodeGenFunction::CreateMemTemp(QualType Ty, const Twine &Name,
                                         Address *Alloca) {
    // FIXME: Should we prefer the preferred type alignment here?
    return CreateMemTemp(Ty, getContext().getTypeAlignInChars(Ty), Name, Alloca);
  }
  
  Address CodeGenFunction::CreateMemTemp(QualType Ty, CharUnits Align,
                                         const Twine &Name, Address *Alloca) {
    return CreateTempAlloca(ConvertTypeForMem(Ty), Align, Name,
                            /*ArraySize=*/nullptr, Alloca);
  }
  
  Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty, CharUnits Align,
                                                    const Twine &Name) {
    return CreateTempAllocaWithoutCast(ConvertTypeForMem(Ty), Align, Name);
  }
  
  Address CodeGenFunction::CreateMemTempWithoutCast(QualType Ty,
                                                    const Twine &Name) {
    return CreateMemTempWithoutCast(Ty, getContext().getTypeAlignInChars(Ty),
                                    Name);
  }
  
  /// EvaluateExprAsBool - Perform the usual unary conversions on the specified
  /// expression and compare the result against zero, returning an Int1Ty value.
  llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
    PGO.setCurrentStmt(E);
    if (const MemberPointerType *MPT = E->getType()->getAs<MemberPointerType>()) {
      llvm::Value *MemPtr = EmitScalarExpr(E);
      return CGM.getCXXABI().EmitMemberPointerIsNotNull(*this, MemPtr, MPT);
    }
  
    QualType BoolTy = getContext().BoolTy;
    SourceLocation Loc = E->getExprLoc();
    if (!E->getType()->isAnyComplexType())
      return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy, Loc);
  
    return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(), BoolTy,
                                         Loc);
  }
  
  /// EmitIgnoredExpr - Emit code to compute the specified expression,
  /// ignoring the result.
  void CodeGenFunction::EmitIgnoredExpr(const Expr *E) {
    if (E->isRValue())
      return (void) EmitAnyExpr(E, AggValueSlot::ignored(), true);
  
    // Just emit it as an l-value and drop the result.
    EmitLValue(E);
  }
  
  /// EmitAnyExpr - Emit code to compute the specified expression which
  /// can have any type.  The result is returned as an RValue struct.
  /// If this is an aggregate expression, AggSlot indicates where the
  /// result should be returned.
  RValue CodeGenFunction::EmitAnyExpr(const Expr *E,
                                      AggValueSlot aggSlot,
                                      bool ignoreResult) {
    switch (getEvaluationKind(E->getType())) {
    case TEK_Scalar:
      return RValue::get(EmitScalarExpr(E, ignoreResult));
    case TEK_Complex:
      return RValue::getComplex(EmitComplexExpr(E, ignoreResult, ignoreResult));
    case TEK_Aggregate:
      if (!ignoreResult && aggSlot.isIgnored())
        aggSlot = CreateAggTemp(E->getType(), "agg-temp");
      EmitAggExpr(E, aggSlot);
      return aggSlot.asRValue();
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  /// EmitAnyExprToTemp - Similar to EmitAnyExpr(), however, the result will
  /// always be accessible even if no aggregate location is provided.
  RValue CodeGenFunction::EmitAnyExprToTemp(const Expr *E) {
    AggValueSlot AggSlot = AggValueSlot::ignored();
  
    if (hasAggregateEvaluationKind(E->getType()))
      AggSlot = CreateAggTemp(E->getType(), "agg.tmp");
    return EmitAnyExpr(E, AggSlot);
  }
  
  /// EmitAnyExprToMem - Evaluate an expression into a given memory
  /// location.
  void CodeGenFunction::EmitAnyExprToMem(const Expr *E,
                                         Address Location,
                                         Qualifiers Quals,
                                         bool IsInit) {
    // FIXME: This function should take an LValue as an argument.
    switch (getEvaluationKind(E->getType())) {
    case TEK_Complex:
      EmitComplexExprIntoLValue(E, MakeAddrLValue(Location, E->getType()),
                                /*isInit*/ false);
      return;
  
    case TEK_Aggregate: {
      EmitAggExpr(E, AggValueSlot::forAddr(Location, Quals,
                                           AggValueSlot::IsDestructed_t(IsInit),
                                           AggValueSlot::DoesNotNeedGCBarriers,
                                           AggValueSlot::IsAliased_t(!IsInit),
                                           AggValueSlot::MayOverlap));
      return;
    }
  
    case TEK_Scalar: {
      RValue RV = RValue::get(EmitScalarExpr(E, /*Ignore*/ false));
      LValue LV = MakeAddrLValue(Location, E->getType());
      EmitStoreThroughLValue(RV, LV);
      return;
    }
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  static void
  pushTemporaryCleanup(CodeGenFunction &CGF, const MaterializeTemporaryExpr *M,
                       const Expr *E, Address ReferenceTemporary) {
    // Objective-C++ ARC:
    //   If we are binding a reference to a temporary that has ownership, we
    //   need to perform retain/release operations on the temporary.
    //
    // FIXME: This should be looking at E, not M.
    if (auto Lifetime = M->getType().getObjCLifetime()) {
      switch (Lifetime) {
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
        // Carry on to normal cleanup handling.
        break;
  
      case Qualifiers::OCL_Autoreleasing:
        // Nothing to do; cleaned up by an autorelease pool.
        return;
  
      case Qualifiers::OCL_Strong:
      case Qualifiers::OCL_Weak:
        switch (StorageDuration Duration = M->getStorageDuration()) {
        case SD_Static:
          // Note: we intentionally do not register a cleanup to release
          // the object on program termination.
          return;
  
        case SD_Thread:
          // FIXME: We should probably register a cleanup in this case.
          return;
  
        case SD_Automatic:
        case SD_FullExpression:
          CodeGenFunction::Destroyer *Destroy;
          CleanupKind CleanupKind;
          if (Lifetime == Qualifiers::OCL_Strong) {
            const ValueDecl *VD = M->getExtendingDecl();
            bool Precise =
                VD && isa<VarDecl>(VD) && VD->hasAttr<ObjCPreciseLifetimeAttr>();
            CleanupKind = CGF.getARCCleanupKind();
            Destroy = Precise ? &CodeGenFunction::destroyARCStrongPrecise
                              : &CodeGenFunction::destroyARCStrongImprecise;
          } else {
            // __weak objects always get EH cleanups; otherwise, exceptions
            // could cause really nasty crashes instead of mere leaks.
            CleanupKind = NormalAndEHCleanup;
            Destroy = &CodeGenFunction::destroyARCWeak;
          }
          if (Duration == SD_FullExpression)
            CGF.pushDestroy(CleanupKind, ReferenceTemporary,
                            M->getType(), *Destroy,
                            CleanupKind & EHCleanup);
          else
            CGF.pushLifetimeExtendedDestroy(CleanupKind, ReferenceTemporary,
                                            M->getType(),
                                            *Destroy, CleanupKind & EHCleanup);
          return;
  
        case SD_Dynamic:
          llvm_unreachable("temporary cannot have dynamic storage duration");
        }
        llvm_unreachable("unknown storage duration");
      }
    }
  
    CXXDestructorDecl *ReferenceTemporaryDtor = nullptr;
    if (const RecordType *RT =
            E->getType()->getBaseElementTypeUnsafe()->getAs<RecordType>()) {
      // Get the destructor for the reference temporary.
      auto *ClassDecl = cast<CXXRecordDecl>(RT->getDecl());
      if (!ClassDecl->hasTrivialDestructor())
        ReferenceTemporaryDtor = ClassDecl->getDestructor();
    }
  
    if (!ReferenceTemporaryDtor)
      return;
  
    // Call the destructor for the temporary.
    switch (M->getStorageDuration()) {
    case SD_Static:
    case SD_Thread: {
      llvm::Constant *CleanupFn;
      llvm::Constant *CleanupArg;
      if (E->getType()->isArrayType()) {
        CleanupFn = CodeGenFunction(CGF.CGM).generateDestroyHelper(
            ReferenceTemporary, E->getType(),
            CodeGenFunction::destroyCXXObject, CGF.getLangOpts().Exceptions,
            dyn_cast_or_null<VarDecl>(M->getExtendingDecl()));
        CleanupArg = llvm::Constant::getNullValue(CGF.Int8PtrTy);
      } else {
        CleanupFn = CGF.CGM.getAddrOfCXXStructor(ReferenceTemporaryDtor,
                                                 StructorType::Complete);
        CleanupArg = cast<llvm::Constant>(ReferenceTemporary.getPointer());
      }
      CGF.CGM.getCXXABI().registerGlobalDtor(
          CGF, *cast<VarDecl>(M->getExtendingDecl()), CleanupFn, CleanupArg);
      break;
    }
  
    case SD_FullExpression:
      CGF.pushDestroy(NormalAndEHCleanup, ReferenceTemporary, E->getType(),
                      CodeGenFunction::destroyCXXObject,
                      CGF.getLangOpts().Exceptions);
      break;
  
    case SD_Automatic:
      CGF.pushLifetimeExtendedDestroy(NormalAndEHCleanup,
                                      ReferenceTemporary, E->getType(),
                                      CodeGenFunction::destroyCXXObject,
                                      CGF.getLangOpts().Exceptions);
      break;
  
    case SD_Dynamic:
      llvm_unreachable("temporary cannot have dynamic storage duration");
    }
  }
  
  static Address createReferenceTemporary(CodeGenFunction &CGF,
                                          const MaterializeTemporaryExpr *M,
                                          const Expr *Inner,
                                          Address *Alloca = nullptr) {
    auto &TCG = CGF.getTargetHooks();
    switch (M->getStorageDuration()) {
    case SD_FullExpression:
    case SD_Automatic: {
      // If we have a constant temporary array or record try to promote it into a
      // constant global under the same rules a normal constant would've been
      // promoted. This is easier on the optimizer and generally emits fewer
      // instructions.
      QualType Ty = Inner->getType();
      if (CGF.CGM.getCodeGenOpts().MergeAllConstants &&
          (Ty->isArrayType() || Ty->isRecordType()) &&
          CGF.CGM.isTypeConstant(Ty, true))
        if (auto Init = ConstantEmitter(CGF).tryEmitAbstract(Inner, Ty)) {
          if (auto AddrSpace = CGF.getTarget().getConstantAddressSpace()) {
            auto AS = AddrSpace.getValue();
            auto *GV = new llvm::GlobalVariable(
                CGF.CGM.getModule(), Init->getType(), /*isConstant=*/true,
                llvm::GlobalValue::PrivateLinkage, Init, ".ref.tmp", nullptr,
                llvm::GlobalValue::NotThreadLocal,
                CGF.getContext().getTargetAddressSpace(AS));
            CharUnits alignment = CGF.getContext().getTypeAlignInChars(Ty);
            GV->setAlignment(alignment.getQuantity());
            llvm::Constant *C = GV;
            if (AS != LangAS::Default)
              C = TCG.performAddrSpaceCast(
                  CGF.CGM, GV, AS, LangAS::Default,
                  GV->getValueType()->getPointerTo(
                      CGF.getContext().getTargetAddressSpace(LangAS::Default)));
            // FIXME: Should we put the new global into a COMDAT?
            return Address(C, alignment);
          }
        }
      return CGF.CreateMemTemp(Ty, "ref.tmp", Alloca);
    }
    case SD_Thread:
    case SD_Static:
      return CGF.CGM.GetAddrOfGlobalTemporary(M, Inner);
  
    case SD_Dynamic:
      llvm_unreachable("temporary can't have dynamic storage duration");
    }
    llvm_unreachable("unknown storage duration");
  }
  
  LValue CodeGenFunction::
  EmitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *M) {
    const Expr *E = M->GetTemporaryExpr();
  
    assert((!M->getExtendingDecl() || !isa<VarDecl>(M->getExtendingDecl()) ||
            !cast<VarDecl>(M->getExtendingDecl())->isARCPseudoStrong()) &&
           "Reference should never be pseudo-strong!");
  
    // FIXME: ideally this would use EmitAnyExprToMem, however, we cannot do so
    // as that will cause the lifetime adjustment to be lost for ARC
    auto ownership = M->getType().getObjCLifetime();
    if (ownership != Qualifiers::OCL_None &&
        ownership != Qualifiers::OCL_ExplicitNone) {
      Address Object = createReferenceTemporary(*this, M, E);
      if (auto *Var = dyn_cast<llvm::GlobalVariable>(Object.getPointer())) {
        Object = Address(llvm::ConstantExpr::getBitCast(Var,
                             ConvertTypeForMem(E->getType())
                               ->getPointerTo(Object.getAddressSpace())),
                         Object.getAlignment());
  
        // createReferenceTemporary will promote the temporary to a global with a
        // constant initializer if it can.  It can only do this to a value of
        // ARC-manageable type if the value is global and therefore "immune" to
        // ref-counting operations.  Therefore we have no need to emit either a
        // dynamic initialization or a cleanup and we can just return the address
        // of the temporary.
        if (Var->hasInitializer())
          return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
  
        Var->setInitializer(CGM.EmitNullConstant(E->getType()));
      }
      LValue RefTempDst = MakeAddrLValue(Object, M->getType(),
                                         AlignmentSource::Decl);
  
      switch (getEvaluationKind(E->getType())) {
      default: llvm_unreachable("expected scalar or aggregate expression");
      case TEK_Scalar:
        EmitScalarInit(E, M->getExtendingDecl(), RefTempDst, false);
        break;
      case TEK_Aggregate: {
        EmitAggExpr(E, AggValueSlot::forAddr(Object,
                                             E->getType().getQualifiers(),
                                             AggValueSlot::IsDestructed,
                                             AggValueSlot::DoesNotNeedGCBarriers,
                                             AggValueSlot::IsNotAliased,
                                             AggValueSlot::DoesNotOverlap));
        break;
      }
      }
  
      pushTemporaryCleanup(*this, M, E, Object);
      return RefTempDst;
    }
  
    SmallVector<const Expr *, 2> CommaLHSs;
    SmallVector<SubobjectAdjustment, 2> Adjustments;
    E = E->skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
  
    for (const auto &Ignored : CommaLHSs)
      EmitIgnoredExpr(Ignored);
  
    if (const auto *opaque = dyn_cast<OpaqueValueExpr>(E)) {
      if (opaque->getType()->isRecordType()) {
        assert(Adjustments.empty());
        return EmitOpaqueValueLValue(opaque);
      }
    }
  
    // Create and initialize the reference temporary.
    Address Alloca = Address::invalid();
    Address Object = createReferenceTemporary(*this, M, E, &Alloca);
    if (auto *Var = dyn_cast<llvm::GlobalVariable>(
            Object.getPointer()->stripPointerCasts())) {
      Object = Address(llvm::ConstantExpr::getBitCast(
                           cast<llvm::Constant>(Object.getPointer()),
                           ConvertTypeForMem(E->getType())->getPointerTo()),
                       Object.getAlignment());
      // If the temporary is a global and has a constant initializer or is a
      // constant temporary that we promoted to a global, we may have already
      // initialized it.
      if (!Var->hasInitializer()) {
        Var->setInitializer(CGM.EmitNullConstant(E->getType()));
        EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
      }
    } else {
      switch (M->getStorageDuration()) {
      case SD_Automatic:
        if (auto *Size = EmitLifetimeStart(
                CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
                Alloca.getPointer())) {
          pushCleanupAfterFullExpr<CallLifetimeEnd>(NormalEHLifetimeMarker,
                                                    Alloca, Size);
        }
        break;
  
      case SD_FullExpression: {
        if (!ShouldEmitLifetimeMarkers)
          break;
  
        // Avoid creating a conditional cleanup just to hold an llvm.lifetime.end
        // marker. Instead, start the lifetime of a conditional temporary earlier
        // so that it's unconditional. Don't do this in ASan's use-after-scope
        // mode so that it gets the more precise lifetime marks. If the type has
        // a non-trivial destructor, we'll have a cleanup block for it anyway,
        // so this typically doesn't help; skip it in that case.
        ConditionalEvaluation *OldConditional = nullptr;
        CGBuilderTy::InsertPoint OldIP;
        if (isInConditionalBranch() && !E->getType().isDestructedType() &&
            !CGM.getCodeGenOpts().SanitizeAddressUseAfterScope) {
          OldConditional = OutermostConditional;
          OutermostConditional = nullptr;
  
          OldIP = Builder.saveIP();
          llvm::BasicBlock *Block = OldConditional->getStartingBlock();
          Builder.restoreIP(CGBuilderTy::InsertPoint(
              Block, llvm::BasicBlock::iterator(Block->back())));
        }
  
        if (auto *Size = EmitLifetimeStart(
                CGM.getDataLayout().getTypeAllocSize(Alloca.getElementType()),
                Alloca.getPointer())) {
          pushFullExprCleanup<CallLifetimeEnd>(NormalEHLifetimeMarker, Alloca,
                                               Size);
        }
  
        if (OldConditional) {
          OutermostConditional = OldConditional;
          Builder.restoreIP(OldIP);
        }
        break;
      }
  
      default:
        break;
      }
      EmitAnyExprToMem(E, Object, Qualifiers(), /*IsInit*/true);
    }
    pushTemporaryCleanup(*this, M, E, Object);
  
    // Perform derived-to-base casts and/or field accesses, to get from the
    // temporary object we created (and, potentially, for which we extended
    // the lifetime) to the subobject we're binding the reference to.
    for (unsigned I = Adjustments.size(); I != 0; --I) {
      SubobjectAdjustment &Adjustment = Adjustments[I-1];
      switch (Adjustment.Kind) {
      case SubobjectAdjustment::DerivedToBaseAdjustment:
        Object =
            GetAddressOfBaseClass(Object, Adjustment.DerivedToBase.DerivedClass,
                                  Adjustment.DerivedToBase.BasePath->path_begin(),
                                  Adjustment.DerivedToBase.BasePath->path_end(),
                                  /*NullCheckValue=*/ false, E->getExprLoc());
        break;
  
      case SubobjectAdjustment::FieldAdjustment: {
        LValue LV = MakeAddrLValue(Object, E->getType(), AlignmentSource::Decl);
        LV = EmitLValueForField(LV, Adjustment.Field);
        assert(LV.isSimple() &&
               "materialized temporary field is not a simple lvalue");
        Object = LV.getAddress();
        break;
      }
  
      case SubobjectAdjustment::MemberPointerAdjustment: {
        llvm::Value *Ptr = EmitScalarExpr(Adjustment.Ptr.RHS);
        Object = EmitCXXMemberDataPointerAddress(E, Object, Ptr,
                                                 Adjustment.Ptr.MPT);
        break;
      }
      }
    }
  
    return MakeAddrLValue(Object, M->getType(), AlignmentSource::Decl);
  }
  
  RValue
  CodeGenFunction::EmitReferenceBindingToExpr(const Expr *E) {
    // Emit the expression as an lvalue.
    LValue LV = EmitLValue(E);
    assert(LV.isSimple());
    llvm::Value *Value = LV.getPointer();
  
    if (sanitizePerformTypeCheck() && !E->getType()->isFunctionType()) {
      // C++11 [dcl.ref]p5 (as amended by core issue 453):
      //   If a glvalue to which a reference is directly bound designates neither
      //   an existing object or function of an appropriate type nor a region of
      //   storage of suitable size and alignment to contain an object of the
      //   reference's type, the behavior is undefined.
      QualType Ty = E->getType();
      EmitTypeCheck(TCK_ReferenceBinding, E->getExprLoc(), Value, Ty);
    }
  
    return RValue::get(Value);
  }
  
  
  /// getAccessedFieldNo - Given an encoded value and a result number, return the
  /// input field number being accessed.
  unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
                                               const llvm::Constant *Elts) {
    return cast<llvm::ConstantInt>(Elts->getAggregateElement(Idx))
        ->getZExtValue();
  }
  
  /// Emit the hash_16_bytes function from include/llvm/ADT/Hashing.h.
  static llvm::Value *emitHash16Bytes(CGBuilderTy &Builder, llvm::Value *Low,
                                      llvm::Value *High) {
    llvm::Value *KMul = Builder.getInt64(0x9ddfea08eb382d69ULL);
    llvm::Value *K47 = Builder.getInt64(47);
    llvm::Value *A0 = Builder.CreateMul(Builder.CreateXor(Low, High), KMul);
    llvm::Value *A1 = Builder.CreateXor(Builder.CreateLShr(A0, K47), A0);
    llvm::Value *B0 = Builder.CreateMul(Builder.CreateXor(High, A1), KMul);
    llvm::Value *B1 = Builder.CreateXor(Builder.CreateLShr(B0, K47), B0);
    return Builder.CreateMul(B1, KMul);
  }
  
  bool CodeGenFunction::isNullPointerAllowed(TypeCheckKind TCK) {
    return TCK == TCK_DowncastPointer || TCK == TCK_Upcast ||
           TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation;
  }
  
  bool CodeGenFunction::isVptrCheckRequired(TypeCheckKind TCK, QualType Ty) {
    CXXRecordDecl *RD = Ty->getAsCXXRecordDecl();
    return (RD && RD->hasDefinition() && RD->isDynamicClass()) &&
           (TCK == TCK_MemberAccess || TCK == TCK_MemberCall ||
            TCK == TCK_DowncastPointer || TCK == TCK_DowncastReference ||
            TCK == TCK_UpcastToVirtualBase || TCK == TCK_DynamicOperation);
  }
  
  bool CodeGenFunction::sanitizePerformTypeCheck() const {
    return SanOpts.has(SanitizerKind::Null) |
           SanOpts.has(SanitizerKind::Alignment) |
           SanOpts.has(SanitizerKind::ObjectSize) |
           SanOpts.has(SanitizerKind::Vptr);
  }
  
  void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
                                      llvm::Value *Ptr, QualType Ty,
                                      CharUnits Alignment,
                                      SanitizerSet SkippedChecks,
                                      llvm::Value *ArraySize) {
    if (!sanitizePerformTypeCheck())
      return;
  
    // Don't check pointers outside the default address space. The null check
    // isn't correct, the object-size check isn't supported by LLVM, and we can't
    // communicate the addresses to the runtime handler for the vptr check.
    if (Ptr->getType()->getPointerAddressSpace())
      return;
  
    // Don't check pointers to volatile data. The behavior here is implementation-
    // defined.
    if (Ty.isVolatileQualified())
      return;
  
    SanitizerScope SanScope(this);
  
    SmallVector<std::pair<llvm::Value *, SanitizerMask>, 3> Checks;
    llvm::BasicBlock *Done = nullptr;
  
    // Quickly determine whether we have a pointer to an alloca. It's possible
    // to skip null checks, and some alignment checks, for these pointers. This
    // can reduce compile-time significantly.
    auto PtrToAlloca =
        dyn_cast<llvm::AllocaInst>(Ptr->stripPointerCastsNoFollowAliases());
  
    llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext());
    llvm::Value *IsNonNull = nullptr;
    bool IsGuaranteedNonNull =
        SkippedChecks.has(SanitizerKind::Null) || PtrToAlloca;
    bool AllowNullPointers = isNullPointerAllowed(TCK);
    if ((SanOpts.has(SanitizerKind::Null) || AllowNullPointers) &&
        !IsGuaranteedNonNull) {
      // The glvalue must not be an empty glvalue.
      IsNonNull = Builder.CreateIsNotNull(Ptr);
  
      // The IR builder can constant-fold the null check if the pointer points to
      // a constant.
      IsGuaranteedNonNull = IsNonNull == True;
  
      // Skip the null check if the pointer is known to be non-null.
      if (!IsGuaranteedNonNull) {
        if (AllowNullPointers) {
          // When performing pointer casts, it's OK if the value is null.
          // Skip the remaining checks in that case.
          Done = createBasicBlock("null");
          llvm::BasicBlock *Rest = createBasicBlock("not.null");
          Builder.CreateCondBr(IsNonNull, Rest, Done);
          EmitBlock(Rest);
        } else {
          Checks.push_back(std::make_pair(IsNonNull, SanitizerKind::Null));
        }
      }
    }
  
    if (SanOpts.has(SanitizerKind::ObjectSize) &&
        !SkippedChecks.has(SanitizerKind::ObjectSize) &&
        !Ty->isIncompleteType()) {
      uint64_t TySize = getContext().getTypeSizeInChars(Ty).getQuantity();
      llvm::Value *Size = llvm::ConstantInt::get(IntPtrTy, TySize);
      if (ArraySize)
        Size = Builder.CreateMul(Size, ArraySize);
  
      // Degenerate case: new X[0] does not need an objectsize check.
      llvm::Constant *ConstantSize = dyn_cast<llvm::Constant>(Size);
      if (!ConstantSize || !ConstantSize->isNullValue()) {
        // The glvalue must refer to a large enough storage region.
        // FIXME: If Address Sanitizer is enabled, insert dynamic instrumentation
        //        to check this.
        // FIXME: Get object address space
        llvm::Type *Tys[2] = { IntPtrTy, Int8PtrTy };
        llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
        llvm::Value *Min = Builder.getFalse();
        llvm::Value *NullIsUnknown = Builder.getFalse();
        llvm::Value *CastAddr = Builder.CreateBitCast(Ptr, Int8PtrTy);
        llvm::Value *LargeEnough = Builder.CreateICmpUGE(
            Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown}), Size);
        Checks.push_back(std::make_pair(LargeEnough, SanitizerKind::ObjectSize));
      }
    }
  
    uint64_t AlignVal = 0;
    llvm::Value *PtrAsInt = nullptr;
  
    if (SanOpts.has(SanitizerKind::Alignment) &&
        !SkippedChecks.has(SanitizerKind::Alignment)) {
      AlignVal = Alignment.getQuantity();
      if (!Ty->isIncompleteType() && !AlignVal)
        AlignVal = getContext().getTypeAlignInChars(Ty).getQuantity();
  
      // The glvalue must be suitably aligned.
      if (AlignVal > 1 &&
          (!PtrToAlloca || PtrToAlloca->getAlignment() < AlignVal)) {
        PtrAsInt = Builder.CreatePtrToInt(Ptr, IntPtrTy);
        llvm::Value *Align = Builder.CreateAnd(
            PtrAsInt, llvm::ConstantInt::get(IntPtrTy, AlignVal - 1));
        llvm::Value *Aligned =
            Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
        if (Aligned != True)
          Checks.push_back(std::make_pair(Aligned, SanitizerKind::Alignment));
      }
    }
  
    if (Checks.size() > 0) {
      // Make sure we're not losing information. Alignment needs to be a power of
      // 2
      assert(!AlignVal || (uint64_t)1 << llvm::Log2_64(AlignVal) == AlignVal);
      llvm::Constant *StaticData[] = {
          EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty),
          llvm::ConstantInt::get(Int8Ty, AlignVal ? llvm::Log2_64(AlignVal) : 1),
          llvm::ConstantInt::get(Int8Ty, TCK)};
      EmitCheck(Checks, SanitizerHandler::TypeMismatch, StaticData,
                PtrAsInt ? PtrAsInt : Ptr);
    }
  
    // If possible, check that the vptr indicates that there is a subobject of
    // type Ty at offset zero within this object.
    //
    // C++11 [basic.life]p5,6:
    //   [For storage which does not refer to an object within its lifetime]
    //   The program has undefined behavior if:
    //    -- the [pointer or glvalue] is used to access a non-static data member
    //       or call a non-static member function
    if (SanOpts.has(SanitizerKind::Vptr) &&
        !SkippedChecks.has(SanitizerKind::Vptr) && isVptrCheckRequired(TCK, Ty)) {
      // Ensure that the pointer is non-null before loading it. If there is no
      // compile-time guarantee, reuse the run-time null check or emit a new one.
      if (!IsGuaranteedNonNull) {
        if (!IsNonNull)
          IsNonNull = Builder.CreateIsNotNull(Ptr);
        if (!Done)
          Done = createBasicBlock("vptr.null");
        llvm::BasicBlock *VptrNotNull = createBasicBlock("vptr.not.null");
        Builder.CreateCondBr(IsNonNull, VptrNotNull, Done);
        EmitBlock(VptrNotNull);
      }
  
      // Compute a hash of the mangled name of the type.
      //
      // FIXME: This is not guaranteed to be deterministic! Move to a
      //        fingerprinting mechanism once LLVM provides one. For the time
      //        being the implementation happens to be deterministic.
      SmallString<64> MangledName;
      llvm::raw_svector_ostream Out(MangledName);
      CGM.getCXXABI().getMangleContext().mangleCXXRTTI(Ty.getUnqualifiedType(),
                                                       Out);
  
      // Blacklist based on the mangled type.
      if (!CGM.getContext().getSanitizerBlacklist().isBlacklistedType(
              SanitizerKind::Vptr, Out.str())) {
        llvm::hash_code TypeHash = hash_value(Out.str());
  
        // Load the vptr, and compute hash_16_bytes(TypeHash, vptr).
        llvm::Value *Low = llvm::ConstantInt::get(Int64Ty, TypeHash);
        llvm::Type *VPtrTy = llvm::PointerType::get(IntPtrTy, 0);
        Address VPtrAddr(Builder.CreateBitCast(Ptr, VPtrTy), getPointerAlign());
        llvm::Value *VPtrVal = Builder.CreateLoad(VPtrAddr);
        llvm::Value *High = Builder.CreateZExt(VPtrVal, Int64Ty);
  
        llvm::Value *Hash = emitHash16Bytes(Builder, Low, High);
        Hash = Builder.CreateTrunc(Hash, IntPtrTy);
  
        // Look the hash up in our cache.
        const int CacheSize = 128;
        llvm::Type *HashTable = llvm::ArrayType::get(IntPtrTy, CacheSize);
        llvm::Value *Cache = CGM.CreateRuntimeVariable(HashTable,
                                                       "__ubsan_vptr_type_cache");
        llvm::Value *Slot = Builder.CreateAnd(Hash,
                                              llvm::ConstantInt::get(IntPtrTy,
                                                                     CacheSize-1));
        llvm::Value *Indices[] = { Builder.getInt32(0), Slot };
        llvm::Value *CacheVal =
          Builder.CreateAlignedLoad(Builder.CreateInBoundsGEP(Cache, Indices),
                                    getPointerAlign());
  
        // If the hash isn't in the cache, call a runtime handler to perform the
        // hard work of checking whether the vptr is for an object of the right
        // type. This will either fill in the cache and return, or produce a
        // diagnostic.
        llvm::Value *EqualHash = Builder.CreateICmpEQ(CacheVal, Hash);
        llvm::Constant *StaticData[] = {
          EmitCheckSourceLocation(Loc),
          EmitCheckTypeDescriptor(Ty),
          CGM.GetAddrOfRTTIDescriptor(Ty.getUnqualifiedType()),
          llvm::ConstantInt::get(Int8Ty, TCK)
        };
        llvm::Value *DynamicData[] = { Ptr, Hash };
        EmitCheck(std::make_pair(EqualHash, SanitizerKind::Vptr),
                  SanitizerHandler::DynamicTypeCacheMiss, StaticData,
                  DynamicData);
      }
    }
  
    if (Done) {
      Builder.CreateBr(Done);
      EmitBlock(Done);
    }
  }
  
  /// Determine whether this expression refers to a flexible array member in a
  /// struct. We disable array bounds checks for such members.
  static bool isFlexibleArrayMemberExpr(const Expr *E) {
    // For compatibility with existing code, we treat arrays of length 0 or
    // 1 as flexible array members.
    const ArrayType *AT = E->getType()->castAsArrayTypeUnsafe();
    if (const auto *CAT = dyn_cast<ConstantArrayType>(AT)) {
      if (CAT->getSize().ugt(1))
        return false;
    } else if (!isa<IncompleteArrayType>(AT))
      return false;
  
    E = E->IgnoreParens();
  
    // A flexible array member must be the last member in the class.
    if (const auto *ME = dyn_cast<MemberExpr>(E)) {
      // FIXME: If the base type of the member expr is not FD->getParent(),
      // this should not be treated as a flexible array member access.
      if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
        RecordDecl::field_iterator FI(
            DeclContext::decl_iterator(const_cast<FieldDecl *>(FD)));
        return ++FI == FD->getParent()->field_end();
      }
    } else if (const auto *IRE = dyn_cast<ObjCIvarRefExpr>(E)) {
      return IRE->getDecl()->getNextIvar() == nullptr;
    }
  
    return false;
  }
  
  llvm::Value *CodeGenFunction::LoadPassedObjectSize(const Expr *E,
                                                     QualType EltTy) {
    ASTContext &C = getContext();
    uint64_t EltSize = C.getTypeSizeInChars(EltTy).getQuantity();
    if (!EltSize)
      return nullptr;
  
    auto *ArrayDeclRef = dyn_cast<DeclRefExpr>(E->IgnoreParenImpCasts());
    if (!ArrayDeclRef)
      return nullptr;
  
    auto *ParamDecl = dyn_cast<ParmVarDecl>(ArrayDeclRef->getDecl());
    if (!ParamDecl)
      return nullptr;
  
    auto *POSAttr = ParamDecl->getAttr<PassObjectSizeAttr>();
    if (!POSAttr)
      return nullptr;
  
    // Don't load the size if it's a lower bound.
    int POSType = POSAttr->getType();
    if (POSType != 0 && POSType != 1)
      return nullptr;
  
    // Find the implicit size parameter.
    auto PassedSizeIt = SizeArguments.find(ParamDecl);
    if (PassedSizeIt == SizeArguments.end())
      return nullptr;
  
    const ImplicitParamDecl *PassedSizeDecl = PassedSizeIt->second;
    assert(LocalDeclMap.count(PassedSizeDecl) && "Passed size not loadable");
    Address AddrOfSize = LocalDeclMap.find(PassedSizeDecl)->second;
    llvm::Value *SizeInBytes = EmitLoadOfScalar(AddrOfSize, /*Volatile=*/false,
                                                C.getSizeType(), E->getExprLoc());
    llvm::Value *SizeOfElement =
        llvm::ConstantInt::get(SizeInBytes->getType(), EltSize);
    return Builder.CreateUDiv(SizeInBytes, SizeOfElement);
  }
  
  /// If Base is known to point to the start of an array, return the length of
  /// that array. Return 0 if the length cannot be determined.
  static llvm::Value *getArrayIndexingBound(
      CodeGenFunction &CGF, const Expr *Base, QualType &IndexedType) {
    // For the vector indexing extension, the bound is the number of elements.
    if (const VectorType *VT = Base->getType()->getAs<VectorType>()) {
      IndexedType = Base->getType();
      return CGF.Builder.getInt32(VT->getNumElements());
    }
  
    Base = Base->IgnoreParens();
  
    if (const auto *CE = dyn_cast<CastExpr>(Base)) {
      if (CE->getCastKind() == CK_ArrayToPointerDecay &&
          !isFlexibleArrayMemberExpr(CE->getSubExpr())) {
        IndexedType = CE->getSubExpr()->getType();
        const ArrayType *AT = IndexedType->castAsArrayTypeUnsafe();
        if (const auto *CAT = dyn_cast<ConstantArrayType>(AT))
          return CGF.Builder.getInt(CAT->getSize());
        else if (const auto *VAT = dyn_cast<VariableArrayType>(AT))
          return CGF.getVLASize(VAT).NumElts;
        // Ignore pass_object_size here. It's not applicable on decayed pointers.
      }
    }
  
    QualType EltTy{Base->getType()->getPointeeOrArrayElementType(), 0};
    if (llvm::Value *POS = CGF.LoadPassedObjectSize(Base, EltTy)) {
      IndexedType = Base->getType();
      return POS;
    }
  
    return nullptr;
  }
  
  void CodeGenFunction::EmitBoundsCheck(const Expr *E, const Expr *Base,
                                        llvm::Value *Index, QualType IndexType,
                                        bool Accessed) {
    assert(SanOpts.has(SanitizerKind::ArrayBounds) &&
           "should not be called unless adding bounds checks");
    SanitizerScope SanScope(this);
  
    QualType IndexedType;
    llvm::Value *Bound = getArrayIndexingBound(*this, Base, IndexedType);
    if (!Bound)
      return;
  
    bool IndexSigned = IndexType->isSignedIntegerOrEnumerationType();
    llvm::Value *IndexVal = Builder.CreateIntCast(Index, SizeTy, IndexSigned);
    llvm::Value *BoundVal = Builder.CreateIntCast(Bound, SizeTy, false);
  
    llvm::Constant *StaticData[] = {
      EmitCheckSourceLocation(E->getExprLoc()),
      EmitCheckTypeDescriptor(IndexedType),
      EmitCheckTypeDescriptor(IndexType)
    };
    llvm::Value *Check = Accessed ? Builder.CreateICmpULT(IndexVal, BoundVal)
                                  : Builder.CreateICmpULE(IndexVal, BoundVal);
    EmitCheck(std::make_pair(Check, SanitizerKind::ArrayBounds),
              SanitizerHandler::OutOfBounds, StaticData, Index);
  }
  
  
  CodeGenFunction::ComplexPairTy CodeGenFunction::
  EmitComplexPrePostIncDec(const UnaryOperator *E, LValue LV,
                           bool isInc, bool isPre) {
    ComplexPairTy InVal = EmitLoadOfComplex(LV, E->getExprLoc());
  
    llvm::Value *NextVal;
    if (isa<llvm::IntegerType>(InVal.first->getType())) {
      uint64_t AmountVal = isInc ? 1 : -1;
      NextVal = llvm::ConstantInt::get(InVal.first->getType(), AmountVal, true);
  
      // Add the inc/dec to the real part.
      NextVal = Builder.CreateAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
    } else {
      QualType ElemTy = E->getType()->getAs<ComplexType>()->getElementType();
      llvm::APFloat FVal(getContext().getFloatTypeSemantics(ElemTy), 1);
      if (!isInc)
        FVal.changeSign();
      NextVal = llvm::ConstantFP::get(getLLVMContext(), FVal);
  
      // Add the inc/dec to the real part.
      NextVal = Builder.CreateFAdd(InVal.first, NextVal, isInc ? "inc" : "dec");
    }
  
    ComplexPairTy IncVal(NextVal, InVal.second);
  
    // Store the updated result through the lvalue.
    EmitStoreOfComplex(IncVal, LV, /*init*/ false);
  
    // If this is a postinc, return the value read from memory, otherwise use the
    // updated value.
    return isPre ? IncVal : InVal;
  }
  
  void CodeGenModule::EmitExplicitCastExprType(const ExplicitCastExpr *E,
                                               CodeGenFunction *CGF) {
    // Bind VLAs in the cast type.
    if (CGF && E->getType()->isVariablyModifiedType())
      CGF->EmitVariablyModifiedType(E->getType());
  
    if (CGDebugInfo *DI = getModuleDebugInfo())
      DI->EmitExplicitCastType(E->getType());
  }
  
  //===----------------------------------------------------------------------===//
  //                         LValue Expression Emission
  //===----------------------------------------------------------------------===//
  
  /// EmitPointerWithAlignment - Given an expression of pointer type, try to
  /// derive a more accurate bound on the alignment of the pointer.
  Address CodeGenFunction::EmitPointerWithAlignment(const Expr *E,
                                                    LValueBaseInfo *BaseInfo,
                                                    TBAAAccessInfo *TBAAInfo) {
    // We allow this with ObjC object pointers because of fragile ABIs.
    assert(E->getType()->isPointerType() ||
           E->getType()->isObjCObjectPointerType());
    E = E->IgnoreParens();
  
    // Casts:
    if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
      if (const auto *ECE = dyn_cast<ExplicitCastExpr>(CE))
        CGM.EmitExplicitCastExprType(ECE, this);
  
      switch (CE->getCastKind()) {
      // Non-converting casts (but not C's implicit conversion from void*).
      case CK_BitCast:
      case CK_NoOp:
      case CK_AddressSpaceConversion:
        if (auto PtrTy = CE->getSubExpr()->getType()->getAs<PointerType>()) {
          if (PtrTy->getPointeeType()->isVoidType())
            break;
  
          LValueBaseInfo InnerBaseInfo;
          TBAAAccessInfo InnerTBAAInfo;
          Address Addr = EmitPointerWithAlignment(CE->getSubExpr(),
                                                  &InnerBaseInfo,
                                                  &InnerTBAAInfo);
          if (BaseInfo) *BaseInfo = InnerBaseInfo;
          if (TBAAInfo) *TBAAInfo = InnerTBAAInfo;
  
          if (isa<ExplicitCastExpr>(CE)) {
            LValueBaseInfo TargetTypeBaseInfo;
            TBAAAccessInfo TargetTypeTBAAInfo;
            CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(),
                                                             &TargetTypeBaseInfo,
                                                             &TargetTypeTBAAInfo);
            if (TBAAInfo)
              *TBAAInfo = CGM.mergeTBAAInfoForCast(*TBAAInfo,
                                                   TargetTypeTBAAInfo);
            // If the source l-value is opaque, honor the alignment of the
            // casted-to type.
            if (InnerBaseInfo.getAlignmentSource() != AlignmentSource::Decl) {
              if (BaseInfo)
                BaseInfo->mergeForCast(TargetTypeBaseInfo);
              Addr = Address(Addr.getPointer(), Align);
            }
          }
  
          if (SanOpts.has(SanitizerKind::CFIUnrelatedCast) &&
              CE->getCastKind() == CK_BitCast) {
            if (auto PT = E->getType()->getAs<PointerType>())
              EmitVTablePtrCheckForCast(PT->getPointeeType(), Addr.getPointer(),
                                        /*MayBeNull=*/true,
                                        CodeGenFunction::CFITCK_UnrelatedCast,
                                        CE->getBeginLoc());
          }
          return CE->getCastKind() != CK_AddressSpaceConversion
                     ? Builder.CreateBitCast(Addr, ConvertType(E->getType()))
                     : Builder.CreateAddrSpaceCast(Addr,
                                                   ConvertType(E->getType()));
        }
        break;
  
      // Array-to-pointer decay.
      case CK_ArrayToPointerDecay:
        return EmitArrayToPointerDecay(CE->getSubExpr(), BaseInfo, TBAAInfo);
  
      // Derived-to-base conversions.
      case CK_UncheckedDerivedToBase:
      case CK_DerivedToBase: {
        // TODO: Support accesses to members of base classes in TBAA. For now, we
        // conservatively pretend that the complete object is of the base class
        // type.
        if (TBAAInfo)
          *TBAAInfo = CGM.getTBAAAccessInfo(E->getType());
        Address Addr = EmitPointerWithAlignment(CE->getSubExpr(), BaseInfo);
        auto Derived = CE->getSubExpr()->getType()->getPointeeCXXRecordDecl();
        return GetAddressOfBaseClass(Addr, Derived,
                                     CE->path_begin(), CE->path_end(),
                                     ShouldNullCheckClassCastValue(CE),
                                     CE->getExprLoc());
      }
  
      // TODO: Is there any reason to treat base-to-derived conversions
      // specially?
      default:
        break;
      }
    }
  
    // Unary &.
    if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
      if (UO->getOpcode() == UO_AddrOf) {
        LValue LV = EmitLValue(UO->getSubExpr());
        if (BaseInfo) *BaseInfo = LV.getBaseInfo();
        if (TBAAInfo) *TBAAInfo = LV.getTBAAInfo();
        return LV.getAddress();
      }
    }
  
    // TODO: conditional operators, comma.
  
    // Otherwise, use the alignment of the type.
    CharUnits Align = getNaturalPointeeTypeAlignment(E->getType(), BaseInfo,
                                                     TBAAInfo);
    return Address(EmitScalarExpr(E), Align);
  }
  
  RValue CodeGenFunction::GetUndefRValue(QualType Ty) {
    if (Ty->isVoidType())
      return RValue::get(nullptr);
  
    switch (getEvaluationKind(Ty)) {
    case TEK_Complex: {
      llvm::Type *EltTy =
        ConvertType(Ty->castAs<ComplexType>()->getElementType());
      llvm::Value *U = llvm::UndefValue::get(EltTy);
      return RValue::getComplex(std::make_pair(U, U));
    }
  
    // If this is a use of an undefined aggregate type, the aggregate must have an
    // identifiable address.  Just because the contents of the value are undefined
    // doesn't mean that the address can't be taken and compared.
    case TEK_Aggregate: {
      Address DestPtr = CreateMemTemp(Ty, "undef.agg.tmp");
      return RValue::getAggregate(DestPtr);
    }
  
    case TEK_Scalar:
      return RValue::get(llvm::UndefValue::get(ConvertType(Ty)));
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  RValue CodeGenFunction::EmitUnsupportedRValue(const Expr *E,
                                                const char *Name) {
    ErrorUnsupported(E, Name);
    return GetUndefRValue(E->getType());
  }
  
  LValue CodeGenFunction::EmitUnsupportedLValue(const Expr *E,
                                                const char *Name) {
    ErrorUnsupported(E, Name);
    llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
    return MakeAddrLValue(Address(llvm::UndefValue::get(Ty), CharUnits::One()),
                          E->getType());
  }
  
  bool CodeGenFunction::IsWrappedCXXThis(const Expr *Obj) {
    const Expr *Base = Obj;
    while (!isa<CXXThisExpr>(Base)) {
      // The result of a dynamic_cast can be null.
      if (isa<CXXDynamicCastExpr>(Base))
        return false;
  
      if (const auto *CE = dyn_cast<CastExpr>(Base)) {
        Base = CE->getSubExpr();
      } else if (const auto *PE = dyn_cast<ParenExpr>(Base)) {
        Base = PE->getSubExpr();
      } else if (const auto *UO = dyn_cast<UnaryOperator>(Base)) {
        if (UO->getOpcode() == UO_Extension)
          Base = UO->getSubExpr();
        else
          return false;
      } else {
        return false;
      }
    }
    return true;
  }
  
  LValue CodeGenFunction::EmitCheckedLValue(const Expr *E, TypeCheckKind TCK) {
    LValue LV;
    if (SanOpts.has(SanitizerKind::ArrayBounds) && isa<ArraySubscriptExpr>(E))
      LV = EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E), /*Accessed*/true);
    else
      LV = EmitLValue(E);
    if (!isa<DeclRefExpr>(E) && !LV.isBitField() && LV.isSimple()) {
      SanitizerSet SkippedChecks;
      if (const auto *ME = dyn_cast<MemberExpr>(E)) {
        bool IsBaseCXXThis = IsWrappedCXXThis(ME->getBase());
        if (IsBaseCXXThis)
          SkippedChecks.set(SanitizerKind::Alignment, true);
        if (IsBaseCXXThis || isa<DeclRefExpr>(ME->getBase()))
          SkippedChecks.set(SanitizerKind::Null, true);
      }
      EmitTypeCheck(TCK, E->getExprLoc(), LV.getPointer(),
                    E->getType(), LV.getAlignment(), SkippedChecks);
    }
    return LV;
  }
  
  /// EmitLValue - Emit code to compute a designator that specifies the location
  /// of the expression.
  ///
  /// This can return one of two things: a simple address or a bitfield reference.
  /// In either case, the LLVM Value* in the LValue structure is guaranteed to be
  /// an LLVM pointer type.
  ///
  /// If this returns a bitfield reference, nothing about the pointee type of the
  /// LLVM value is known: For example, it may not be a pointer to an integer.
  ///
  /// If this returns a normal address, and if the lvalue's C type is fixed size,
  /// this method guarantees that the returned pointer type will point to an LLVM
  /// type of the same size of the lvalue's type.  If the lvalue has a variable
  /// length type, this is not possible.
  ///
  LValue CodeGenFunction::EmitLValue(const Expr *E) {
    ApplyDebugLocation DL(*this, E);
    switch (E->getStmtClass()) {
    default: return EmitUnsupportedLValue(E, "l-value expression");
  
    case Expr::ObjCPropertyRefExprClass:
      llvm_unreachable("cannot emit a property reference directly");
  
    case Expr::ObjCSelectorExprClass:
      return EmitObjCSelectorLValue(cast<ObjCSelectorExpr>(E));
    case Expr::ObjCIsaExprClass:
      return EmitObjCIsaExpr(cast<ObjCIsaExpr>(E));
    case Expr::BinaryOperatorClass:
      return EmitBinaryOperatorLValue(cast<BinaryOperator>(E));
    case Expr::CompoundAssignOperatorClass: {
      QualType Ty = E->getType();
      if (const AtomicType *AT = Ty->getAs<AtomicType>())
        Ty = AT->getValueType();
      if (!Ty->isAnyComplexType())
        return EmitCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
      return EmitComplexCompoundAssignmentLValue(cast<CompoundAssignOperator>(E));
    }
    case Expr::CallExprClass:
    case Expr::CXXMemberCallExprClass:
    case Expr::CXXOperatorCallExprClass:
    case Expr::UserDefinedLiteralClass:
      return EmitCallExprLValue(cast<CallExpr>(E));
    case Expr::VAArgExprClass:
      return EmitVAArgExprLValue(cast<VAArgExpr>(E));
    case Expr::DeclRefExprClass:
      return EmitDeclRefLValue(cast<DeclRefExpr>(E));
    case Expr::ConstantExprClass:
      return EmitLValue(cast<ConstantExpr>(E)->getSubExpr());
    case Expr::ParenExprClass:
      return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
    case Expr::GenericSelectionExprClass:
      return EmitLValue(cast<GenericSelectionExpr>(E)->getResultExpr());
    case Expr::PredefinedExprClass:
      return EmitPredefinedLValue(cast<PredefinedExpr>(E));
    case Expr::StringLiteralClass:
      return EmitStringLiteralLValue(cast<StringLiteral>(E));
    case Expr::ObjCEncodeExprClass:
      return EmitObjCEncodeExprLValue(cast<ObjCEncodeExpr>(E));
    case Expr::PseudoObjectExprClass:
      return EmitPseudoObjectLValue(cast<PseudoObjectExpr>(E));
    case Expr::InitListExprClass:
      return EmitInitListLValue(cast<InitListExpr>(E));
    case Expr::CXXTemporaryObjectExprClass:
    case Expr::CXXConstructExprClass:
      return EmitCXXConstructLValue(cast<CXXConstructExpr>(E));
    case Expr::CXXBindTemporaryExprClass:
      return EmitCXXBindTemporaryLValue(cast<CXXBindTemporaryExpr>(E));
    case Expr::CXXUuidofExprClass:
      return EmitCXXUuidofLValue(cast<CXXUuidofExpr>(E));
  
    case Expr::ExprWithCleanupsClass: {
      const auto *cleanups = cast<ExprWithCleanups>(E);
      enterFullExpression(cleanups);
      RunCleanupsScope Scope(*this);
      LValue LV = EmitLValue(cleanups->getSubExpr());
      if (LV.isSimple()) {
        // Defend against branches out of gnu statement expressions surrounded by
        // cleanups.
        llvm::Value *V = LV.getPointer();
        Scope.ForceCleanup({&V});
        return LValue::MakeAddr(Address(V, LV.getAlignment()), LV.getType(),
                                getContext(), LV.getBaseInfo(), LV.getTBAAInfo());
      }
      // FIXME: Is it possible to create an ExprWithCleanups that produces a
      // bitfield lvalue or some other non-simple lvalue?
      return LV;
    }
  
    case Expr::CXXDefaultArgExprClass:
      return EmitLValue(cast<CXXDefaultArgExpr>(E)->getExpr());
    case Expr::CXXDefaultInitExprClass: {
      CXXDefaultInitExprScope Scope(*this);
      return EmitLValue(cast<CXXDefaultInitExpr>(E)->getExpr());
    }
    case Expr::CXXTypeidExprClass:
      return EmitCXXTypeidLValue(cast<CXXTypeidExpr>(E));
  
    case Expr::ObjCMessageExprClass:
      return EmitObjCMessageExprLValue(cast<ObjCMessageExpr>(E));
    case Expr::ObjCIvarRefExprClass:
      return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
    case Expr::StmtExprClass:
      return EmitStmtExprLValue(cast<StmtExpr>(E));
    case Expr::UnaryOperatorClass:
      return EmitUnaryOpLValue(cast<UnaryOperator>(E));
    case Expr::ArraySubscriptExprClass:
      return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
    case Expr::OMPArraySectionExprClass:
      return EmitOMPArraySectionExpr(cast<OMPArraySectionExpr>(E));
    case Expr::ExtVectorElementExprClass:
      return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
    case Expr::MemberExprClass:
      return EmitMemberExpr(cast<MemberExpr>(E));
    case Expr::CompoundLiteralExprClass:
      return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
    case Expr::ConditionalOperatorClass:
      return EmitConditionalOperatorLValue(cast<ConditionalOperator>(E));
    case Expr::BinaryConditionalOperatorClass:
      return EmitConditionalOperatorLValue(cast<BinaryConditionalOperator>(E));
    case Expr::ChooseExprClass:
      return EmitLValue(cast<ChooseExpr>(E)->getChosenSubExpr());
    case Expr::OpaqueValueExprClass:
      return EmitOpaqueValueLValue(cast<OpaqueValueExpr>(E));
    case Expr::SubstNonTypeTemplateParmExprClass:
      return EmitLValue(cast<SubstNonTypeTemplateParmExpr>(E)->getReplacement());
    case Expr::ImplicitCastExprClass:
    case Expr::CStyleCastExprClass:
    case Expr::CXXFunctionalCastExprClass:
    case Expr::CXXStaticCastExprClass:
    case Expr::CXXDynamicCastExprClass:
    case Expr::CXXReinterpretCastExprClass:
    case Expr::CXXConstCastExprClass:
    case Expr::ObjCBridgedCastExprClass:
      return EmitCastLValue(cast<CastExpr>(E));
  
    case Expr::MaterializeTemporaryExprClass:
      return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
  
    case Expr::CoawaitExprClass:
      return EmitCoawaitLValue(cast<CoawaitExpr>(E));
    case Expr::CoyieldExprClass:
      return EmitCoyieldLValue(cast<CoyieldExpr>(E));
    }
  }
  
  /// Given an object of the given canonical type, can we safely copy a
  /// value out of it based on its initializer?
  static bool isConstantEmittableObjectType(QualType type) {
    assert(type.isCanonical());
    assert(!type->isReferenceType());
  
    // Must be const-qualified but non-volatile.
    Qualifiers qs = type.getLocalQualifiers();
    if (!qs.hasConst() || qs.hasVolatile()) return false;
  
    // Otherwise, all object types satisfy this except C++ classes with
    // mutable subobjects or non-trivial copy/destroy behavior.
    if (const auto *RT = dyn_cast<RecordType>(type))
      if (const auto *RD = dyn_cast<CXXRecordDecl>(RT->getDecl()))
        if (RD->hasMutableFields() || !RD->isTrivial())
          return false;
  
    return true;
  }
  
  /// Can we constant-emit a load of a reference to a variable of the
  /// given type?  This is different from predicates like
  /// Decl::isUsableInConstantExpressions because we do want it to apply
  /// in situations that don't necessarily satisfy the language's rules
  /// for this (e.g. C++'s ODR-use rules).  For example, we want to able
  /// to do this with const float variables even if those variables
  /// aren't marked 'constexpr'.
  enum ConstantEmissionKind {
    CEK_None,
    CEK_AsReferenceOnly,
    CEK_AsValueOrReference,
    CEK_AsValueOnly
  };
  static ConstantEmissionKind checkVarTypeForConstantEmission(QualType type) {
    type = type.getCanonicalType();
    if (const auto *ref = dyn_cast<ReferenceType>(type)) {
      if (isConstantEmittableObjectType(ref->getPointeeType()))
        return CEK_AsValueOrReference;
      return CEK_AsReferenceOnly;
    }
    if (isConstantEmittableObjectType(type))
      return CEK_AsValueOnly;
    return CEK_None;
  }
  
  /// Try to emit a reference to the given value without producing it as
  /// an l-value.  This is actually more than an optimization: we can't
  /// produce an l-value for variables that we never actually captured
  /// in a block or lambda, which means const int variables or constexpr
  /// literals or similar.
  CodeGenFunction::ConstantEmission
  CodeGenFunction::tryEmitAsConstant(DeclRefExpr *refExpr) {
    ValueDecl *value = refExpr->getDecl();
  
    // The value needs to be an enum constant or a constant variable.
    ConstantEmissionKind CEK;
    if (isa<ParmVarDecl>(value)) {
      CEK = CEK_None;
    } else if (auto *var = dyn_cast<VarDecl>(value)) {
      CEK = checkVarTypeForConstantEmission(var->getType());
    } else if (isa<EnumConstantDecl>(value)) {
      CEK = CEK_AsValueOnly;
    } else {
      CEK = CEK_None;
    }
    if (CEK == CEK_None) return ConstantEmission();
  
    Expr::EvalResult result;
    bool resultIsReference;
    QualType resultType;
  
    // It's best to evaluate all the way as an r-value if that's permitted.
    if (CEK != CEK_AsReferenceOnly &&
        refExpr->EvaluateAsRValue(result, getContext())) {
      resultIsReference = false;
      resultType = refExpr->getType();
  
    // Otherwise, try to evaluate as an l-value.
    } else if (CEK != CEK_AsValueOnly &&
               refExpr->EvaluateAsLValue(result, getContext())) {
      resultIsReference = true;
      resultType = value->getType();
  
    // Failure.
    } else {
      return ConstantEmission();
    }
  
    // In any case, if the initializer has side-effects, abandon ship.
    if (result.HasSideEffects)
      return ConstantEmission();
  
    // Emit as a constant.
    auto C = ConstantEmitter(*this).emitAbstract(refExpr->getLocation(),
                                                 result.Val, resultType);
  
    // Make sure we emit a debug reference to the global variable.
    // This should probably fire even for
    if (isa<VarDecl>(value)) {
      if (!getContext().DeclMustBeEmitted(cast<VarDecl>(value)))
        EmitDeclRefExprDbgValue(refExpr, result.Val);
    } else {
      assert(isa<EnumConstantDecl>(value));
      EmitDeclRefExprDbgValue(refExpr, result.Val);
    }
  
    // If we emitted a reference constant, we need to dereference that.
    if (resultIsReference)
      return ConstantEmission::forReference(C);
  
    return ConstantEmission::forValue(C);
  }
  
  static DeclRefExpr *tryToConvertMemberExprToDeclRefExpr(CodeGenFunction &CGF,
                                                          const MemberExpr *ME) {
    if (auto *VD = dyn_cast<VarDecl>(ME->getMemberDecl())) {
      // Try to emit static variable member expressions as DREs.
      return DeclRefExpr::Create(
          CGF.getContext(), NestedNameSpecifierLoc(), SourceLocation(), VD,
          /*RefersToEnclosingVariableOrCapture=*/false, ME->getExprLoc(),
          ME->getType(), ME->getValueKind());
    }
    return nullptr;
  }
  
  CodeGenFunction::ConstantEmission
  CodeGenFunction::tryEmitAsConstant(const MemberExpr *ME) {
    if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, ME))
      return tryEmitAsConstant(DRE);
    return ConstantEmission();
  }
  
  llvm::Value *CodeGenFunction::emitScalarConstant(
      const CodeGenFunction::ConstantEmission &Constant, Expr *E) {
    assert(Constant && "not a constant");
    if (Constant.isReference())
      return EmitLoadOfLValue(Constant.getReferenceLValue(*this, E),
                              E->getExprLoc())
          .getScalarVal();
    return Constant.getValue();
  }
  
  llvm::Value *CodeGenFunction::EmitLoadOfScalar(LValue lvalue,
                                                 SourceLocation Loc) {
    return EmitLoadOfScalar(lvalue.getAddress(), lvalue.isVolatile(),
                            lvalue.getType(), Loc, lvalue.getBaseInfo(),
                            lvalue.getTBAAInfo(), lvalue.isNontemporal());
  }
  
  static bool hasBooleanRepresentation(QualType Ty) {
    if (Ty->isBooleanType())
      return true;
  
    if (const EnumType *ET = Ty->getAs<EnumType>())
      return ET->getDecl()->getIntegerType()->isBooleanType();
  
    if (const AtomicType *AT = Ty->getAs<AtomicType>())
      return hasBooleanRepresentation(AT->getValueType());
  
    return false;
  }
  
  static bool getRangeForType(CodeGenFunction &CGF, QualType Ty,
                              llvm::APInt &Min, llvm::APInt &End,
                              bool StrictEnums, bool IsBool) {
    const EnumType *ET = Ty->getAs<EnumType>();
    bool IsRegularCPlusPlusEnum = CGF.getLangOpts().CPlusPlus && StrictEnums &&
                                  ET && !ET->getDecl()->isFixed();
    if (!IsBool && !IsRegularCPlusPlusEnum)
      return false;
  
    if (IsBool) {
      Min = llvm::APInt(CGF.getContext().getTypeSize(Ty), 0);
      End = llvm::APInt(CGF.getContext().getTypeSize(Ty), 2);
    } else {
      const EnumDecl *ED = ET->getDecl();
      llvm::Type *LTy = CGF.ConvertTypeForMem(ED->getIntegerType());
      unsigned Bitwidth = LTy->getScalarSizeInBits();
      unsigned NumNegativeBits = ED->getNumNegativeBits();
      unsigned NumPositiveBits = ED->getNumPositiveBits();
  
      if (NumNegativeBits) {
        unsigned NumBits = std::max(NumNegativeBits, NumPositiveBits + 1);
        assert(NumBits <= Bitwidth);
        End = llvm::APInt(Bitwidth, 1) << (NumBits - 1);
        Min = -End;
      } else {
        assert(NumPositiveBits <= Bitwidth);
        End = llvm::APInt(Bitwidth, 1) << NumPositiveBits;
        Min = llvm::APInt(Bitwidth, 0);
      }
    }
    return true;
  }
  
  llvm::MDNode *CodeGenFunction::getRangeForLoadFromType(QualType Ty) {
    llvm::APInt Min, End;
    if (!getRangeForType(*this, Ty, Min, End, CGM.getCodeGenOpts().StrictEnums,
                         hasBooleanRepresentation(Ty)))
      return nullptr;
  
    llvm::MDBuilder MDHelper(getLLVMContext());
    return MDHelper.createRange(Min, End);
  }
  
  bool CodeGenFunction::EmitScalarRangeCheck(llvm::Value *Value, QualType Ty,
                                             SourceLocation Loc) {
    bool HasBoolCheck = SanOpts.has(SanitizerKind::Bool);
    bool HasEnumCheck = SanOpts.has(SanitizerKind::Enum);
    if (!HasBoolCheck && !HasEnumCheck)
      return false;
  
    bool IsBool = hasBooleanRepresentation(Ty) ||
                  NSAPI(CGM.getContext()).isObjCBOOLType(Ty);
    bool NeedsBoolCheck = HasBoolCheck && IsBool;
    bool NeedsEnumCheck = HasEnumCheck && Ty->getAs<EnumType>();
    if (!NeedsBoolCheck && !NeedsEnumCheck)
      return false;
  
    // Single-bit booleans don't need to be checked. Special-case this to avoid
    // a bit width mismatch when handling bitfield values. This is handled by
    // EmitFromMemory for the non-bitfield case.
    if (IsBool &&
        cast<llvm::IntegerType>(Value->getType())->getBitWidth() == 1)
      return false;
  
    llvm::APInt Min, End;
    if (!getRangeForType(*this, Ty, Min, End, /*StrictEnums=*/true, IsBool))
      return true;
  
    auto &Ctx = getLLVMContext();
    SanitizerScope SanScope(this);
    llvm::Value *Check;
    --End;
    if (!Min) {
      Check = Builder.CreateICmpULE(Value, llvm::ConstantInt::get(Ctx, End));
    } else {
      llvm::Value *Upper =
          Builder.CreateICmpSLE(Value, llvm::ConstantInt::get(Ctx, End));
      llvm::Value *Lower =
          Builder.CreateICmpSGE(Value, llvm::ConstantInt::get(Ctx, Min));
      Check = Builder.CreateAnd(Upper, Lower);
    }
    llvm::Constant *StaticArgs[] = {EmitCheckSourceLocation(Loc),
                                    EmitCheckTypeDescriptor(Ty)};
    SanitizerMask Kind =
        NeedsEnumCheck ? SanitizerKind::Enum : SanitizerKind::Bool;
    EmitCheck(std::make_pair(Check, Kind), SanitizerHandler::LoadInvalidValue,
              StaticArgs, EmitCheckValue(Value));
    return true;
  }
  
  llvm::Value *CodeGenFunction::EmitLoadOfScalar(Address Addr, bool Volatile,
                                                 QualType Ty,
                                                 SourceLocation Loc,
                                                 LValueBaseInfo BaseInfo,
                                                 TBAAAccessInfo TBAAInfo,
                                                 bool isNontemporal) {
    if (!CGM.getCodeGenOpts().PreserveVec3Type) {
      // For better performance, handle vector loads differently.
      if (Ty->isVectorType()) {
        const llvm::Type *EltTy = Addr.getElementType();
  
        const auto *VTy = cast<llvm::VectorType>(EltTy);
  
        // Handle vectors of size 3 like size 4 for better performance.
        if (VTy->getNumElements() == 3) {
  
          // Bitcast to vec4 type.
          llvm::VectorType *vec4Ty =
              llvm::VectorType::get(VTy->getElementType(), 4);
          Address Cast = Builder.CreateElementBitCast(Addr, vec4Ty, "castToVec4");
          // Now load value.
          llvm::Value *V = Builder.CreateLoad(Cast, Volatile, "loadVec4");
  
          // Shuffle vector to get vec3.
          V = Builder.CreateShuffleVector(V, llvm::UndefValue::get(vec4Ty),
                                          {0, 1, 2}, "extractVec");
          return EmitFromMemory(V, Ty);
        }
      }
    }
  
    // Atomic operations have to be done on integral types.
    LValue AtomicLValue =
        LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo);
    if (Ty->isAtomicType() || LValueIsSuitableForInlineAtomic(AtomicLValue)) {
      return EmitAtomicLoad(AtomicLValue, Loc).getScalarVal();
    }
  
    llvm::LoadInst *Load = Builder.CreateLoad(Addr, Volatile);
    if (isNontemporal) {
      llvm::MDNode *Node = llvm::MDNode::get(
          Load->getContext(), llvm::ConstantAsMetadata::get(Builder.getInt32(1)));
      Load->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
    }
  
    CGM.DecorateInstructionWithTBAA(Load, TBAAInfo);
  
    if (EmitScalarRangeCheck(Load, Ty, Loc)) {
      // In order to prevent the optimizer from throwing away the check, don't
      // attach range metadata to the load.
    } else if (CGM.getCodeGenOpts().OptimizationLevel > 0)
      if (llvm::MDNode *RangeInfo = getRangeForLoadFromType(Ty))
        Load->setMetadata(llvm::LLVMContext::MD_range, RangeInfo);
  
    return EmitFromMemory(Load, Ty);
  }
  
  llvm::Value *CodeGenFunction::EmitToMemory(llvm::Value *Value, QualType Ty) {
    // Bool has a different representation in memory than in registers.
    if (hasBooleanRepresentation(Ty)) {
      // This should really always be an i1, but sometimes it's already
      // an i8, and it's awkward to track those cases down.
      if (Value->getType()->isIntegerTy(1))
        return Builder.CreateZExt(Value, ConvertTypeForMem(Ty), "frombool");
      assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) &&
             "wrong value rep of bool");
    }
  
    return Value;
  }
  
  llvm::Value *CodeGenFunction::EmitFromMemory(llvm::Value *Value, QualType Ty) {
    // Bool has a different representation in memory than in registers.
    if (hasBooleanRepresentation(Ty)) {
      assert(Value->getType()->isIntegerTy(getContext().getTypeSize(Ty)) &&
             "wrong value rep of bool");
      return Builder.CreateTrunc(Value, Builder.getInt1Ty(), "tobool");
    }
  
    return Value;
  }
  
  void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, Address Addr,
                                          bool Volatile, QualType Ty,
                                          LValueBaseInfo BaseInfo,
                                          TBAAAccessInfo TBAAInfo,
                                          bool isInit, bool isNontemporal) {
    if (!CGM.getCodeGenOpts().PreserveVec3Type) {
      // Handle vectors differently to get better performance.
      if (Ty->isVectorType()) {
        llvm::Type *SrcTy = Value->getType();
        auto *VecTy = dyn_cast<llvm::VectorType>(SrcTy);
        // Handle vec3 special.
        if (VecTy && VecTy->getNumElements() == 3) {
          // Our source is a vec3, do a shuffle vector to make it a vec4.
          llvm::Constant *Mask[] = {Builder.getInt32(0), Builder.getInt32(1),
                                    Builder.getInt32(2),
                                    llvm::UndefValue::get(Builder.getInt32Ty())};
          llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
          Value = Builder.CreateShuffleVector(Value, llvm::UndefValue::get(VecTy),
                                              MaskV, "extractVec");
          SrcTy = llvm::VectorType::get(VecTy->getElementType(), 4);
        }
        if (Addr.getElementType() != SrcTy) {
          Addr = Builder.CreateElementBitCast(Addr, SrcTy, "storetmp");
        }
      }
    }
  
    Value = EmitToMemory(Value, Ty);
  
    LValue AtomicLValue =
        LValue::MakeAddr(Addr, Ty, getContext(), BaseInfo, TBAAInfo);
    if (Ty->isAtomicType() ||
        (!isInit && LValueIsSuitableForInlineAtomic(AtomicLValue))) {
      EmitAtomicStore(RValue::get(Value), AtomicLValue, isInit);
      return;
    }
  
    llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
    if (isNontemporal) {
      llvm::MDNode *Node =
          llvm::MDNode::get(Store->getContext(),
                            llvm::ConstantAsMetadata::get(Builder.getInt32(1)));
      Store->setMetadata(CGM.getModule().getMDKindID("nontemporal"), Node);
    }
  
    CGM.DecorateInstructionWithTBAA(Store, TBAAInfo);
  }
  
  void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
                                          bool isInit) {
    EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
                      lvalue.getType(), lvalue.getBaseInfo(),
                      lvalue.getTBAAInfo(), isInit, lvalue.isNontemporal());
  }
  
  /// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
  /// method emits the address of the lvalue, then loads the result as an rvalue,
  /// returning the rvalue.
  RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, SourceLocation Loc) {
    if (LV.isObjCWeak()) {
      // load of a __weak object.
      Address AddrWeakObj = LV.getAddress();
      return RValue::get(CGM.getObjCRuntime().EmitObjCWeakRead(*this,
                                                               AddrWeakObj));
    }
    if (LV.getQuals().getObjCLifetime() == Qualifiers::OCL_Weak) {
      // In MRC mode, we do a load+autorelease.
      if (!getLangOpts().ObjCAutoRefCount) {
        return RValue::get(EmitARCLoadWeak(LV.getAddress()));
      }
  
      // In ARC mode, we load retained and then consume the value.
      llvm::Value *Object = EmitARCLoadWeakRetained(LV.getAddress());
      Object = EmitObjCConsumeObject(LV.getType(), Object);
      return RValue::get(Object);
    }
  
    if (LV.isSimple()) {
      assert(!LV.getType()->isFunctionType());
  
      // Everything needs a load.
      return RValue::get(EmitLoadOfScalar(LV, Loc));
    }
  
    if (LV.isVectorElt()) {
      llvm::LoadInst *Load = Builder.CreateLoad(LV.getVectorAddress(),
                                                LV.isVolatileQualified());
      return RValue::get(Builder.CreateExtractElement(Load, LV.getVectorIdx(),
                                                      "vecext"));
    }
  
    // If this is a reference to a subset of the elements of a vector, either
    // shuffle the input or extract/insert them as appropriate.
    if (LV.isExtVectorElt())
      return EmitLoadOfExtVectorElementLValue(LV);
  
    // Global Register variables always invoke intrinsics
    if (LV.isGlobalReg())
      return EmitLoadOfGlobalRegLValue(LV);
  
    assert(LV.isBitField() && "Unknown LValue type!");
    return EmitLoadOfBitfieldLValue(LV, Loc);
  }
  
  RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
                                                   SourceLocation Loc) {
    const CGBitFieldInfo &Info = LV.getBitFieldInfo();
  
    // Get the output type.
    llvm::Type *ResLTy = ConvertType(LV.getType());
  
    Address Ptr = LV.getBitFieldAddress();
    llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "bf.load");
  
    if (Info.IsSigned) {
      assert(static_cast<unsigned>(Info.Offset + Info.Size) <= Info.StorageSize);
      unsigned HighBits = Info.StorageSize - Info.Offset - Info.Size;
      if (HighBits)
        Val = Builder.CreateShl(Val, HighBits, "bf.shl");
      if (Info.Offset + HighBits)
        Val = Builder.CreateAShr(Val, Info.Offset + HighBits, "bf.ashr");
    } else {
      if (Info.Offset)
        Val = Builder.CreateLShr(Val, Info.Offset, "bf.lshr");
      if (static_cast<unsigned>(Info.Offset) + Info.Size < Info.StorageSize)
        Val = Builder.CreateAnd(Val, llvm::APInt::getLowBitsSet(Info.StorageSize,
                                                                Info.Size),
                                "bf.clear");
    }
    Val = Builder.CreateIntCast(Val, ResLTy, Info.IsSigned, "bf.cast");
    EmitScalarRangeCheck(Val, LV.getType(), Loc);
    return RValue::get(Val);
  }
  
  // If this is a reference to a subset of the elements of a vector, create an
  // appropriate shufflevector.
  RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV) {
    llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddress(),
                                          LV.isVolatileQualified());
  
    const llvm::Constant *Elts = LV.getExtVectorElts();
  
    // If the result of the expression is a non-vector type, we must be extracting
    // a single element.  Just codegen as an extractelement.
    const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
    if (!ExprVT) {
      unsigned InIdx = getAccessedFieldNo(0, Elts);
      llvm::Value *Elt = llvm::ConstantInt::get(SizeTy, InIdx);
      return RValue::get(Builder.CreateExtractElement(Vec, Elt));
    }
  
    // Always use shuffle vector to try to retain the original program structure
    unsigned NumResultElts = ExprVT->getNumElements();
  
    SmallVector<llvm::Constant*, 4> Mask;
    for (unsigned i = 0; i != NumResultElts; ++i)
      Mask.push_back(Builder.getInt32(getAccessedFieldNo(i, Elts)));
  
    llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
    Vec = Builder.CreateShuffleVector(Vec, llvm::UndefValue::get(Vec->getType()),
                                      MaskV);
    return RValue::get(Vec);
  }
  
  /// Generates lvalue for partial ext_vector access.
  Address CodeGenFunction::EmitExtVectorElementLValue(LValue LV) {
    Address VectorAddress = LV.getExtVectorAddress();
    const VectorType *ExprVT = LV.getType()->getAs<VectorType>();
    QualType EQT = ExprVT->getElementType();
    llvm::Type *VectorElementTy = CGM.getTypes().ConvertType(EQT);
  
    Address CastToPointerElement =
      Builder.CreateElementBitCast(VectorAddress, VectorElementTy,
                                   "conv.ptr.element");
  
    const llvm::Constant *Elts = LV.getExtVectorElts();
    unsigned ix = getAccessedFieldNo(0, Elts);
  
    Address VectorBasePtrPlusIx =
      Builder.CreateConstInBoundsGEP(CastToPointerElement, ix,
                                     getContext().getTypeSizeInChars(EQT),
                                     "vector.elt");
  
    return VectorBasePtrPlusIx;
  }
  
  /// Load of global gamed gegisters are always calls to intrinsics.
  RValue CodeGenFunction::EmitLoadOfGlobalRegLValue(LValue LV) {
    assert((LV.getType()->isIntegerType() || LV.getType()->isPointerType()) &&
           "Bad type for register variable");
    llvm::MDNode *RegName = cast<llvm::MDNode>(
        cast<llvm::MetadataAsValue>(LV.getGlobalReg())->getMetadata());
  
    // We accept integer and pointer types only
    llvm::Type *OrigTy = CGM.getTypes().ConvertType(LV.getType());
    llvm::Type *Ty = OrigTy;
    if (OrigTy->isPointerTy())
      Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy);
    llvm::Type *Types[] = { Ty };
  
    llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::read_register, Types);
    llvm::Value *Call = Builder.CreateCall(
        F, llvm::MetadataAsValue::get(Ty->getContext(), RegName));
    if (OrigTy->isPointerTy())
      Call = Builder.CreateIntToPtr(Call, OrigTy);
    return RValue::get(Call);
  }
  
  
  /// EmitStoreThroughLValue - Store the specified rvalue into the specified
  /// lvalue, where both are guaranteed to the have the same type, and that type
  /// is 'Ty'.
  void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
                                               bool isInit) {
    if (!Dst.isSimple()) {
      if (Dst.isVectorElt()) {
        // Read/modify/write the vector, inserting the new element.
        llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddress(),
                                              Dst.isVolatileQualified());
        Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
                                          Dst.getVectorIdx(), "vecins");
        Builder.CreateStore(Vec, Dst.getVectorAddress(),
                            Dst.isVolatileQualified());
        return;
      }
  
      // If this is an update of extended vector elements, insert them as
      // appropriate.
      if (Dst.isExtVectorElt())
        return EmitStoreThroughExtVectorComponentLValue(Src, Dst);
  
      if (Dst.isGlobalReg())
        return EmitStoreThroughGlobalRegLValue(Src, Dst);
  
      assert(Dst.isBitField() && "Unknown LValue type");
      return EmitStoreThroughBitfieldLValue(Src, Dst);
    }
  
    // There's special magic for assigning into an ARC-qualified l-value.
    if (Qualifiers::ObjCLifetime Lifetime = Dst.getQuals().getObjCLifetime()) {
      switch (Lifetime) {
      case Qualifiers::OCL_None:
        llvm_unreachable("present but none");
  
      case Qualifiers::OCL_ExplicitNone:
        // nothing special
        break;
  
      case Qualifiers::OCL_Strong:
        if (isInit) {
          Src = RValue::get(EmitARCRetain(Dst.getType(), Src.getScalarVal()));
          break;
        }
        EmitARCStoreStrong(Dst, Src.getScalarVal(), /*ignore*/ true);
        return;
  
      case Qualifiers::OCL_Weak:
        if (isInit)
          // Initialize and then skip the primitive store.
          EmitARCInitWeak(Dst.getAddress(), Src.getScalarVal());
        else
          EmitARCStoreWeak(Dst.getAddress(), Src.getScalarVal(), /*ignore*/ true);
        return;
  
      case Qualifiers::OCL_Autoreleasing:
        Src = RValue::get(EmitObjCExtendObjectLifetime(Dst.getType(),
                                                       Src.getScalarVal()));
        // fall into the normal path
        break;
      }
    }
  
    if (Dst.isObjCWeak() && !Dst.isNonGC()) {
      // load of a __weak object.
      Address LvalueDst = Dst.getAddress();
      llvm::Value *src = Src.getScalarVal();
       CGM.getObjCRuntime().EmitObjCWeakAssign(*this, src, LvalueDst);
      return;
    }
  
    if (Dst.isObjCStrong() && !Dst.isNonGC()) {
      // load of a __strong object.
      Address LvalueDst = Dst.getAddress();
      llvm::Value *src = Src.getScalarVal();
      if (Dst.isObjCIvar()) {
        assert(Dst.getBaseIvarExp() && "BaseIvarExp is NULL");
        llvm::Type *ResultType = IntPtrTy;
        Address dst = EmitPointerWithAlignment(Dst.getBaseIvarExp());
        llvm::Value *RHS = dst.getPointer();
        RHS = Builder.CreatePtrToInt(RHS, ResultType, "sub.ptr.rhs.cast");
        llvm::Value *LHS =
          Builder.CreatePtrToInt(LvalueDst.getPointer(), ResultType,
                                 "sub.ptr.lhs.cast");
        llvm::Value *BytesBetween = Builder.CreateSub(LHS, RHS, "ivar.offset");
        CGM.getObjCRuntime().EmitObjCIvarAssign(*this, src, dst,
                                                BytesBetween);
      } else if (Dst.isGlobalObjCRef()) {
        CGM.getObjCRuntime().EmitObjCGlobalAssign(*this, src, LvalueDst,
                                                  Dst.isThreadLocalRef());
      }
      else
        CGM.getObjCRuntime().EmitObjCStrongCastAssign(*this, src, LvalueDst);
      return;
    }
  
    assert(Src.isScalar() && "Can't emit an agg store with this method");
    EmitStoreOfScalar(Src.getScalarVal(), Dst, isInit);
  }
  
  void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
                                                       llvm::Value **Result) {
    const CGBitFieldInfo &Info = Dst.getBitFieldInfo();
    llvm::Type *ResLTy = ConvertTypeForMem(Dst.getType());
    Address Ptr = Dst.getBitFieldAddress();
  
    // Get the source value, truncated to the width of the bit-field.
    llvm::Value *SrcVal = Src.getScalarVal();
  
    // Cast the source to the storage type and shift it into place.
    SrcVal = Builder.CreateIntCast(SrcVal, Ptr.getElementType(),
                                   /*IsSigned=*/false);
    llvm::Value *MaskedVal = SrcVal;
  
    // See if there are other bits in the bitfield's storage we'll need to load
    // and mask together with source before storing.
    if (Info.StorageSize != Info.Size) {
      assert(Info.StorageSize > Info.Size && "Invalid bitfield size.");
      llvm::Value *Val =
        Builder.CreateLoad(Ptr, Dst.isVolatileQualified(), "bf.load");
  
      // Mask the source value as needed.
      if (!hasBooleanRepresentation(Dst.getType()))
        SrcVal = Builder.CreateAnd(SrcVal,
                                   llvm::APInt::getLowBitsSet(Info.StorageSize,
                                                              Info.Size),
                                   "bf.value");
      MaskedVal = SrcVal;
      if (Info.Offset)
        SrcVal = Builder.CreateShl(SrcVal, Info.Offset, "bf.shl");
  
      // Mask out the original value.
      Val = Builder.CreateAnd(Val,
                              ~llvm::APInt::getBitsSet(Info.StorageSize,
                                                       Info.Offset,
                                                       Info.Offset + Info.Size),
                              "bf.clear");
  
      // Or together the unchanged values and the source value.
      SrcVal = Builder.CreateOr(Val, SrcVal, "bf.set");
    } else {
      assert(Info.Offset == 0);
    }
  
    // Write the new value back out.
    Builder.CreateStore(SrcVal, Ptr, Dst.isVolatileQualified());
  
    // Return the new value of the bit-field, if requested.
    if (Result) {
      llvm::Value *ResultVal = MaskedVal;
  
      // Sign extend the value if needed.
      if (Info.IsSigned) {
        assert(Info.Size <= Info.StorageSize);
        unsigned HighBits = Info.StorageSize - Info.Size;
        if (HighBits) {
          ResultVal = Builder.CreateShl(ResultVal, HighBits, "bf.result.shl");
          ResultVal = Builder.CreateAShr(ResultVal, HighBits, "bf.result.ashr");
        }
      }
  
      ResultVal = Builder.CreateIntCast(ResultVal, ResLTy, Info.IsSigned,
                                        "bf.result.cast");
      *Result = EmitFromMemory(ResultVal, Dst.getType());
    }
  }
  
  void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
                                                                 LValue Dst) {
    // This access turns into a read/modify/write of the vector.  Load the input
    // value now.
    llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddress(),
                                          Dst.isVolatileQualified());
    const llvm::Constant *Elts = Dst.getExtVectorElts();
  
    llvm::Value *SrcVal = Src.getScalarVal();
  
    if (const VectorType *VTy = Dst.getType()->getAs<VectorType>()) {
      unsigned NumSrcElts = VTy->getNumElements();
      unsigned NumDstElts = Vec->getType()->getVectorNumElements();
      if (NumDstElts == NumSrcElts) {
        // Use shuffle vector is the src and destination are the same number of
        // elements and restore the vector mask since it is on the side it will be
        // stored.
        SmallVector<llvm::Constant*, 4> Mask(NumDstElts);
        for (unsigned i = 0; i != NumSrcElts; ++i)
          Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i);
  
        llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
        Vec = Builder.CreateShuffleVector(SrcVal,
                                          llvm::UndefValue::get(Vec->getType()),
                                          MaskV);
      } else if (NumDstElts > NumSrcElts) {
        // Extended the source vector to the same length and then shuffle it
        // into the destination.
        // FIXME: since we're shuffling with undef, can we just use the indices
        //        into that?  This could be simpler.
        SmallVector<llvm::Constant*, 4> ExtMask;
        for (unsigned i = 0; i != NumSrcElts; ++i)
          ExtMask.push_back(Builder.getInt32(i));
        ExtMask.resize(NumDstElts, llvm::UndefValue::get(Int32Ty));
        llvm::Value *ExtMaskV = llvm::ConstantVector::get(ExtMask);
        llvm::Value *ExtSrcVal =
          Builder.CreateShuffleVector(SrcVal,
                                      llvm::UndefValue::get(SrcVal->getType()),
                                      ExtMaskV);
        // build identity
        SmallVector<llvm::Constant*, 4> Mask;
        for (unsigned i = 0; i != NumDstElts; ++i)
          Mask.push_back(Builder.getInt32(i));
  
        // When the vector size is odd and .odd or .hi is used, the last element
        // of the Elts constant array will be one past the size of the vector.
        // Ignore the last element here, if it is greater than the mask size.
        if (getAccessedFieldNo(NumSrcElts - 1, Elts) == Mask.size())
          NumSrcElts--;
  
        // modify when what gets shuffled in
        for (unsigned i = 0; i != NumSrcElts; ++i)
          Mask[getAccessedFieldNo(i, Elts)] = Builder.getInt32(i+NumDstElts);
        llvm::Value *MaskV = llvm::ConstantVector::get(Mask);
        Vec = Builder.CreateShuffleVector(Vec, ExtSrcVal, MaskV);
      } else {
        // We should never shorten the vector
        llvm_unreachable("unexpected shorten vector length");
      }
    } else {
      // If the Src is a scalar (not a vector) it must be updating one element.
      unsigned InIdx = getAccessedFieldNo(0, Elts);
      llvm::Value *Elt = llvm::ConstantInt::get(SizeTy, InIdx);
      Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt);
    }
  
    Builder.CreateStore(Vec, Dst.getExtVectorAddress(),
                        Dst.isVolatileQualified());
  }
  
  /// Store of global named registers are always calls to intrinsics.
  void CodeGenFunction::EmitStoreThroughGlobalRegLValue(RValue Src, LValue Dst) {
    assert((Dst.getType()->isIntegerType() || Dst.getType()->isPointerType()) &&
           "Bad type for register variable");
    llvm::MDNode *RegName = cast<llvm::MDNode>(
        cast<llvm::MetadataAsValue>(Dst.getGlobalReg())->getMetadata());
    assert(RegName && "Register LValue is not metadata");
  
    // We accept integer and pointer types only
    llvm::Type *OrigTy = CGM.getTypes().ConvertType(Dst.getType());
    llvm::Type *Ty = OrigTy;
    if (OrigTy->isPointerTy())
      Ty = CGM.getTypes().getDataLayout().getIntPtrType(OrigTy);
    llvm::Type *Types[] = { Ty };
  
    llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::write_register, Types);
    llvm::Value *Value = Src.getScalarVal();
    if (OrigTy->isPointerTy())
      Value = Builder.CreatePtrToInt(Value, Ty);
    Builder.CreateCall(
        F, {llvm::MetadataAsValue::get(Ty->getContext(), RegName), Value});
  }
  
  // setObjCGCLValueClass - sets class of the lvalue for the purpose of
  // generating write-barries API. It is currently a global, ivar,
  // or neither.
  static void setObjCGCLValueClass(const ASTContext &Ctx, const Expr *E,
                                   LValue &LV,
                                   bool IsMemberAccess=false) {
    if (Ctx.getLangOpts().getGC() == LangOptions::NonGC)
      return;
  
    if (isa<ObjCIvarRefExpr>(E)) {
      QualType ExpTy = E->getType();
      if (IsMemberAccess && ExpTy->isPointerType()) {
        // If ivar is a structure pointer, assigning to field of
        // this struct follows gcc's behavior and makes it a non-ivar
        // writer-barrier conservatively.
        ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
        if (ExpTy->isRecordType()) {
          LV.setObjCIvar(false);
          return;
        }
      }
      LV.setObjCIvar(true);
      auto *Exp = cast<ObjCIvarRefExpr>(const_cast<Expr *>(E));
      LV.setBaseIvarExp(Exp->getBase());
      LV.setObjCArray(E->getType()->isArrayType());
      return;
    }
  
    if (const auto *Exp = dyn_cast<DeclRefExpr>(E)) {
      if (const auto *VD = dyn_cast<VarDecl>(Exp->getDecl())) {
        if (VD->hasGlobalStorage()) {
          LV.setGlobalObjCRef(true);
          LV.setThreadLocalRef(VD->getTLSKind() != VarDecl::TLS_None);
        }
      }
      LV.setObjCArray(E->getType()->isArrayType());
      return;
    }
  
    if (const auto *Exp = dyn_cast<UnaryOperator>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
      return;
    }
  
    if (const auto *Exp = dyn_cast<ParenExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
      if (LV.isObjCIvar()) {
        // If cast is to a structure pointer, follow gcc's behavior and make it
        // a non-ivar write-barrier.
        QualType ExpTy = E->getType();
        if (ExpTy->isPointerType())
          ExpTy = ExpTy->getAs<PointerType>()->getPointeeType();
        if (ExpTy->isRecordType())
          LV.setObjCIvar(false);
      }
      return;
    }
  
    if (const auto *Exp = dyn_cast<GenericSelectionExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getResultExpr(), LV);
      return;
    }
  
    if (const auto *Exp = dyn_cast<ImplicitCastExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
      return;
    }
  
    if (const auto *Exp = dyn_cast<CStyleCastExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
      return;
    }
  
    if (const auto *Exp = dyn_cast<ObjCBridgedCastExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getSubExpr(), LV, IsMemberAccess);
      return;
    }
  
    if (const auto *Exp = dyn_cast<ArraySubscriptExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getBase(), LV);
      if (LV.isObjCIvar() && !LV.isObjCArray())
        // Using array syntax to assigning to what an ivar points to is not
        // same as assigning to the ivar itself. {id *Names;} Names[i] = 0;
        LV.setObjCIvar(false);
      else if (LV.isGlobalObjCRef() && !LV.isObjCArray())
        // Using array syntax to assigning to what global points to is not
        // same as assigning to the global itself. {id *G;} G[i] = 0;
        LV.setGlobalObjCRef(false);
      return;
    }
  
    if (const auto *Exp = dyn_cast<MemberExpr>(E)) {
      setObjCGCLValueClass(Ctx, Exp->getBase(), LV, true);
      // We don't know if member is an 'ivar', but this flag is looked at
      // only in the context of LV.isObjCIvar().
      LV.setObjCArray(E->getType()->isArrayType());
      return;
    }
  }
  
  static llvm::Value *
  EmitBitCastOfLValueToProperType(CodeGenFunction &CGF,
                                  llvm::Value *V, llvm::Type *IRType,
                                  StringRef Name = StringRef()) {
    unsigned AS = cast<llvm::PointerType>(V->getType())->getAddressSpace();
    return CGF.Builder.CreateBitCast(V, IRType->getPointerTo(AS), Name);
  }
  
  static LValue EmitThreadPrivateVarDeclLValue(
      CodeGenFunction &CGF, const VarDecl *VD, QualType T, Address Addr,
      llvm::Type *RealVarTy, SourceLocation Loc) {
    Addr = CGF.CGM.getOpenMPRuntime().getAddrOfThreadPrivate(CGF, VD, Addr, Loc);
    Addr = CGF.Builder.CreateElementBitCast(Addr, RealVarTy);
    return CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl);
  }
  
  static Address emitDeclTargetLinkVarDeclLValue(CodeGenFunction &CGF,
                                                 const VarDecl *VD, QualType T) {
    llvm::Optional<OMPDeclareTargetDeclAttr::MapTypeTy> Res =
        OMPDeclareTargetDeclAttr::isDeclareTargetDeclaration(VD);
    if (!Res || *Res == OMPDeclareTargetDeclAttr::MT_To)
      return Address::invalid();
    assert(*Res == OMPDeclareTargetDeclAttr::MT_Link && "Expected link clause");
    QualType PtrTy = CGF.getContext().getPointerType(VD->getType());
    Address Addr = CGF.CGM.getOpenMPRuntime().getAddrOfDeclareTargetLink(VD);
    return CGF.EmitLoadOfPointer(Addr, PtrTy->castAs<PointerType>());
  }
  
  Address
  CodeGenFunction::EmitLoadOfReference(LValue RefLVal,
                                       LValueBaseInfo *PointeeBaseInfo,
                                       TBAAAccessInfo *PointeeTBAAInfo) {
    llvm::LoadInst *Load = Builder.CreateLoad(RefLVal.getAddress(),
                                              RefLVal.isVolatile());
    CGM.DecorateInstructionWithTBAA(Load, RefLVal.getTBAAInfo());
  
    CharUnits Align = getNaturalTypeAlignment(RefLVal.getType()->getPointeeType(),
                                              PointeeBaseInfo, PointeeTBAAInfo,
                                              /* forPointeeType= */ true);
    return Address(Load, Align);
  }
  
  LValue CodeGenFunction::EmitLoadOfReferenceLValue(LValue RefLVal) {
    LValueBaseInfo PointeeBaseInfo;
    TBAAAccessInfo PointeeTBAAInfo;
    Address PointeeAddr = EmitLoadOfReference(RefLVal, &PointeeBaseInfo,
                                              &PointeeTBAAInfo);
    return MakeAddrLValue(PointeeAddr, RefLVal.getType()->getPointeeType(),
                          PointeeBaseInfo, PointeeTBAAInfo);
  }
  
  Address CodeGenFunction::EmitLoadOfPointer(Address Ptr,
                                             const PointerType *PtrTy,
                                             LValueBaseInfo *BaseInfo,
                                             TBAAAccessInfo *TBAAInfo) {
    llvm::Value *Addr = Builder.CreateLoad(Ptr);
    return Address(Addr, getNaturalTypeAlignment(PtrTy->getPointeeType(),
                                                 BaseInfo, TBAAInfo,
                                                 /*forPointeeType=*/true));
  }
  
  LValue CodeGenFunction::EmitLoadOfPointerLValue(Address PtrAddr,
                                                  const PointerType *PtrTy) {
    LValueBaseInfo BaseInfo;
    TBAAAccessInfo TBAAInfo;
    Address Addr = EmitLoadOfPointer(PtrAddr, PtrTy, &BaseInfo, &TBAAInfo);
    return MakeAddrLValue(Addr, PtrTy->getPointeeType(), BaseInfo, TBAAInfo);
  }
  
  static LValue EmitGlobalVarDeclLValue(CodeGenFunction &CGF,
                                        const Expr *E, const VarDecl *VD) {
    QualType T = E->getType();
  
    // If it's thread_local, emit a call to its wrapper function instead.
    if (VD->getTLSKind() == VarDecl::TLS_Dynamic &&
        CGF.CGM.getCXXABI().usesThreadWrapperFunction())
      return CGF.CGM.getCXXABI().EmitThreadLocalVarDeclLValue(CGF, VD, T);
    // Check if the variable is marked as declare target with link clause in
    // device codegen.
    if (CGF.getLangOpts().OpenMPIsDevice) {
      Address Addr = emitDeclTargetLinkVarDeclLValue(CGF, VD, T);
      if (Addr.isValid())
        return CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl);
    }
  
    llvm::Value *V = CGF.CGM.GetAddrOfGlobalVar(VD);
    llvm::Type *RealVarTy = CGF.getTypes().ConvertTypeForMem(VD->getType());
    V = EmitBitCastOfLValueToProperType(CGF, V, RealVarTy);
    CharUnits Alignment = CGF.getContext().getDeclAlign(VD);
    Address Addr(V, Alignment);
    // Emit reference to the private copy of the variable if it is an OpenMP
    // threadprivate variable.
    if (CGF.getLangOpts().OpenMP && !CGF.getLangOpts().OpenMPSimd &&
        VD->hasAttr<OMPThreadPrivateDeclAttr>()) {
      return EmitThreadPrivateVarDeclLValue(CGF, VD, T, Addr, RealVarTy,
                                            E->getExprLoc());
    }
    LValue LV = VD->getType()->isReferenceType() ?
        CGF.EmitLoadOfReferenceLValue(Addr, VD->getType(),
                                      AlignmentSource::Decl) :
        CGF.MakeAddrLValue(Addr, T, AlignmentSource::Decl);
    setObjCGCLValueClass(CGF.getContext(), E, LV);
    return LV;
  }
  
  static llvm::Constant *EmitFunctionDeclPointer(CodeGenModule &CGM,
                                                 const FunctionDecl *FD) {
    if (FD->hasAttr<WeakRefAttr>()) {
      ConstantAddress aliasee = CGM.GetWeakRefReference(FD);
      return aliasee.getPointer();
    }
  
    llvm::Constant *V = CGM.GetAddrOfFunction(FD);
    if (!FD->hasPrototype()) {
      if (const FunctionProtoType *Proto =
              FD->getType()->getAs<FunctionProtoType>()) {
        // Ugly case: for a K&R-style definition, the type of the definition
        // isn't the same as the type of a use.  Correct for this with a
        // bitcast.
        QualType NoProtoType =
            CGM.getContext().getFunctionNoProtoType(Proto->getReturnType());
        NoProtoType = CGM.getContext().getPointerType(NoProtoType);
        V = llvm::ConstantExpr::getBitCast(V,
                                        CGM.getTypes().ConvertType(NoProtoType));
      }
    }
    return V;
  }
  
  static LValue EmitFunctionDeclLValue(CodeGenFunction &CGF,
                                       const Expr *E, const FunctionDecl *FD) {
    llvm::Value *V = EmitFunctionDeclPointer(CGF.CGM, FD);
    CharUnits Alignment = CGF.getContext().getDeclAlign(FD);
    return CGF.MakeAddrLValue(V, E->getType(), Alignment,
                              AlignmentSource::Decl);
  }
  
  static LValue EmitCapturedFieldLValue(CodeGenFunction &CGF, const FieldDecl *FD,
                                        llvm::Value *ThisValue) {
    QualType TagType = CGF.getContext().getTagDeclType(FD->getParent());
    LValue LV = CGF.MakeNaturalAlignAddrLValue(ThisValue, TagType);
    return CGF.EmitLValueForField(LV, FD);
  }
  
  /// Named Registers are named metadata pointing to the register name
  /// which will be read from/written to as an argument to the intrinsic
  /// @llvm.read/write_register.
  /// So far, only the name is being passed down, but other options such as
  /// register type, allocation type or even optimization options could be
  /// passed down via the metadata node.
  static LValue EmitGlobalNamedRegister(const VarDecl *VD, CodeGenModule &CGM) {
    SmallString<64> Name("llvm.named.register.");
    AsmLabelAttr *Asm = VD->getAttr<AsmLabelAttr>();
    assert(Asm->getLabel().size() < 64-Name.size() &&
        "Register name too big");
    Name.append(Asm->getLabel());
    llvm::NamedMDNode *M =
      CGM.getModule().getOrInsertNamedMetadata(Name);
    if (M->getNumOperands() == 0) {
      llvm::MDString *Str = llvm::MDString::get(CGM.getLLVMContext(),
                                                Asm->getLabel());
      llvm::Metadata *Ops[] = {Str};
      M->addOperand(llvm::MDNode::get(CGM.getLLVMContext(), Ops));
    }
  
    CharUnits Alignment = CGM.getContext().getDeclAlign(VD);
  
    llvm::Value *Ptr =
      llvm::MetadataAsValue::get(CGM.getLLVMContext(), M->getOperand(0));
    return LValue::MakeGlobalReg(Address(Ptr, Alignment), VD->getType());
  }
  
  LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
    const NamedDecl *ND = E->getDecl();
    QualType T = E->getType();
  
    if (const auto *VD = dyn_cast<VarDecl>(ND)) {
      // Global Named registers access via intrinsics only
      if (VD->getStorageClass() == SC_Register &&
          VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())
        return EmitGlobalNamedRegister(VD, CGM);
  
      // A DeclRefExpr for a reference initialized by a constant expression can
      // appear without being odr-used. Directly emit the constant initializer.
      const Expr *Init = VD->getAnyInitializer(VD);
      const auto *BD = dyn_cast_or_null<BlockDecl>(CurCodeDecl);
      if (Init && !isa<ParmVarDecl>(VD) && VD->getType()->isReferenceType() &&
          VD->isUsableInConstantExpressions(getContext()) &&
          VD->checkInitIsICE() &&
          // Do not emit if it is private OpenMP variable.
          !(E->refersToEnclosingVariableOrCapture() &&
            ((CapturedStmtInfo &&
              (LocalDeclMap.count(VD->getCanonicalDecl()) ||
               CapturedStmtInfo->lookup(VD->getCanonicalDecl()))) ||
             LambdaCaptureFields.lookup(VD->getCanonicalDecl()) ||
             (BD && BD->capturesVariable(VD))))) {
        llvm::Constant *Val =
          ConstantEmitter(*this).emitAbstract(E->getLocation(),
                                              *VD->evaluateValue(),
                                              VD->getType());
        assert(Val && "failed to emit reference constant expression");
        // FIXME: Eventually we will want to emit vector element references.
  
        // Should we be using the alignment of the constant pointer we emitted?
        CharUnits Alignment = getNaturalTypeAlignment(E->getType(),
                                                      /* BaseInfo= */ nullptr,
                                                      /* TBAAInfo= */ nullptr,
                                                      /* forPointeeType= */ true);
        return MakeAddrLValue(Address(Val, Alignment), T, AlignmentSource::Decl);
      }
  
      // Check for captured variables.
      if (E->refersToEnclosingVariableOrCapture()) {
        VD = VD->getCanonicalDecl();
        if (auto *FD = LambdaCaptureFields.lookup(VD))
          return EmitCapturedFieldLValue(*this, FD, CXXABIThisValue);
        else if (CapturedStmtInfo) {
          auto I = LocalDeclMap.find(VD);
          if (I != LocalDeclMap.end()) {
            if (VD->getType()->isReferenceType())
              return EmitLoadOfReferenceLValue(I->second, VD->getType(),
                                               AlignmentSource::Decl);
            return MakeAddrLValue(I->second, T);
          }
          LValue CapLVal =
              EmitCapturedFieldLValue(*this, CapturedStmtInfo->lookup(VD),
                                      CapturedStmtInfo->getContextValue());
          return MakeAddrLValue(
              Address(CapLVal.getPointer(), getContext().getDeclAlign(VD)),
              CapLVal.getType(), LValueBaseInfo(AlignmentSource::Decl),
              CapLVal.getTBAAInfo());
        }
  
        assert(isa<BlockDecl>(CurCodeDecl));
        Address addr = GetAddrOfBlockDecl(VD);
        return MakeAddrLValue(addr, T, AlignmentSource::Decl);
      }
    }
  
    // FIXME: We should be able to assert this for FunctionDecls as well!
    // FIXME: We should be able to assert this for all DeclRefExprs, not just
    // those with a valid source location.
    assert((ND->isUsed(false) || !isa<VarDecl>(ND) ||
            !E->getLocation().isValid()) &&
           "Should not use decl without marking it used!");
  
    if (ND->hasAttr<WeakRefAttr>()) {
      const auto *VD = cast<ValueDecl>(ND);
      ConstantAddress Aliasee = CGM.GetWeakRefReference(VD);
      return MakeAddrLValue(Aliasee, T, AlignmentSource::Decl);
    }
  
    if (const auto *VD = dyn_cast<VarDecl>(ND)) {
      // Check if this is a global variable.
      if (VD->hasLinkage() || VD->isStaticDataMember())
        return EmitGlobalVarDeclLValue(*this, E, VD);
  
      Address addr = Address::invalid();
  
      // The variable should generally be present in the local decl map.
      auto iter = LocalDeclMap.find(VD);
      if (iter != LocalDeclMap.end()) {
        addr = iter->second;
  
      // Otherwise, it might be static local we haven't emitted yet for
      // some reason; most likely, because it's in an outer function.
      } else if (VD->isStaticLocal()) {
        addr = Address(CGM.getOrCreateStaticVarDecl(
            *VD, CGM.getLLVMLinkageVarDefinition(VD, /*isConstant=*/false)),
                       getContext().getDeclAlign(VD));
  
      // No other cases for now.
      } else {
        llvm_unreachable("DeclRefExpr for Decl not entered in LocalDeclMap?");
      }
  
  
      // Check for OpenMP threadprivate variables.
      if (getLangOpts().OpenMP && !getLangOpts().OpenMPSimd &&
          VD->hasAttr<OMPThreadPrivateDeclAttr>()) {
        return EmitThreadPrivateVarDeclLValue(
            *this, VD, T, addr, getTypes().ConvertTypeForMem(VD->getType()),
            E->getExprLoc());
      }
  
      // Drill into block byref variables.
      bool isBlockByref = VD->isEscapingByref();
      if (isBlockByref) {
        addr = emitBlockByrefAddress(addr, VD);
      }
  
      // Drill into reference types.
      LValue LV = VD->getType()->isReferenceType() ?
          EmitLoadOfReferenceLValue(addr, VD->getType(), AlignmentSource::Decl) :
          MakeAddrLValue(addr, T, AlignmentSource::Decl);
  
      bool isLocalStorage = VD->hasLocalStorage();
  
      bool NonGCable = isLocalStorage &&
                       !VD->getType()->isReferenceType() &&
                       !isBlockByref;
      if (NonGCable) {
        LV.getQuals().removeObjCGCAttr();
        LV.setNonGC(true);
      }
  
      bool isImpreciseLifetime =
        (isLocalStorage && !VD->hasAttr<ObjCPreciseLifetimeAttr>());
      if (isImpreciseLifetime)
        LV.setARCPreciseLifetime(ARCImpreciseLifetime);
      setObjCGCLValueClass(getContext(), E, LV);
      return LV;
    }
  
    if (const auto *FD = dyn_cast<FunctionDecl>(ND))
      return EmitFunctionDeclLValue(*this, E, FD);
  
    // FIXME: While we're emitting a binding from an enclosing scope, all other
    // DeclRefExprs we see should be implicitly treated as if they also refer to
    // an enclosing scope.
    if (const auto *BD = dyn_cast<BindingDecl>(ND))
      return EmitLValue(BD->getBinding());
  
    llvm_unreachable("Unhandled DeclRefExpr");
  }
  
  LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
    // __extension__ doesn't affect lvalue-ness.
    if (E->getOpcode() == UO_Extension)
      return EmitLValue(E->getSubExpr());
  
    QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
    switch (E->getOpcode()) {
    default: llvm_unreachable("Unknown unary operator lvalue!");
    case UO_Deref: {
      QualType T = E->getSubExpr()->getType()->getPointeeType();
      assert(!T.isNull() && "CodeGenFunction::EmitUnaryOpLValue: Illegal type");
  
      LValueBaseInfo BaseInfo;
      TBAAAccessInfo TBAAInfo;
      Address Addr = EmitPointerWithAlignment(E->getSubExpr(), &BaseInfo,
                                              &TBAAInfo);
      LValue LV = MakeAddrLValue(Addr, T, BaseInfo, TBAAInfo);
      LV.getQuals().setAddressSpace(ExprTy.getAddressSpace());
  
      // We should not generate __weak write barrier on indirect reference
      // of a pointer to object; as in void foo (__weak id *param); *param = 0;
      // But, we continue to generate __strong write barrier on indirect write
      // into a pointer to object.
      if (getLangOpts().ObjC &&
          getLangOpts().getGC() != LangOptions::NonGC &&
          LV.isObjCWeak())
        LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
      return LV;
    }
    case UO_Real:
    case UO_Imag: {
      LValue LV = EmitLValue(E->getSubExpr());
      assert(LV.isSimple() && "real/imag on non-ordinary l-value");
  
      // __real is valid on scalars.  This is a faster way of testing that.
      // __imag can only produce an rvalue on scalars.
      if (E->getOpcode() == UO_Real &&
          !LV.getAddress().getElementType()->isStructTy()) {
        assert(E->getSubExpr()->getType()->isArithmeticType());
        return LV;
      }
  
      QualType T = ExprTy->castAs<ComplexType>()->getElementType();
  
      Address Component =
        (E->getOpcode() == UO_Real
           ? emitAddrOfRealComponent(LV.getAddress(), LV.getType())
           : emitAddrOfImagComponent(LV.getAddress(), LV.getType()));
      LValue ElemLV = MakeAddrLValue(Component, T, LV.getBaseInfo(),
                                     CGM.getTBAAInfoForSubobject(LV, T));
      ElemLV.getQuals().addQualifiers(LV.getQuals());
      return ElemLV;
    }
    case UO_PreInc:
    case UO_PreDec: {
      LValue LV = EmitLValue(E->getSubExpr());
      bool isInc = E->getOpcode() == UO_PreInc;
  
      if (E->getType()->isAnyComplexType())
        EmitComplexPrePostIncDec(E, LV, isInc, true/*isPre*/);
      else
        EmitScalarPrePostIncDec(E, LV, isInc, true/*isPre*/);
      return LV;
    }
    }
  }
  
  LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
    return MakeAddrLValue(CGM.GetAddrOfConstantStringFromLiteral(E),
                          E->getType(), AlignmentSource::Decl);
  }
  
  LValue CodeGenFunction::EmitObjCEncodeExprLValue(const ObjCEncodeExpr *E) {
    return MakeAddrLValue(CGM.GetAddrOfConstantStringFromObjCEncode(E),
                          E->getType(), AlignmentSource::Decl);
  }
  
  LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
    auto SL = E->getFunctionName();
    assert(SL != nullptr && "No StringLiteral name in PredefinedExpr");
    StringRef FnName = CurFn->getName();
    if (FnName.startswith("\01"))
      FnName = FnName.substr(1);
    StringRef NameItems[] = {
        PredefinedExpr::getIdentKindName(E->getIdentKind()), FnName};
    std::string GVName = llvm::join(NameItems, NameItems + 2, ".");
    if (auto *BD = dyn_cast_or_null<BlockDecl>(CurCodeDecl)) {
      std::string Name = SL->getString();
      if (!Name.empty()) {
        unsigned Discriminator =
            CGM.getCXXABI().getMangleContext().getBlockId(BD, true);
        if (Discriminator)
          Name += "_" + Twine(Discriminator + 1).str();
        auto C = CGM.GetAddrOfConstantCString(Name, GVName.c_str());
        return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
      } else {
        auto C = CGM.GetAddrOfConstantCString(FnName, GVName.c_str());
        return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
      }
    }
    auto C = CGM.GetAddrOfConstantStringFromLiteral(SL, GVName);
    return MakeAddrLValue(C, E->getType(), AlignmentSource::Decl);
  }
  
  /// Emit a type description suitable for use by a runtime sanitizer library. The
  /// format of a type descriptor is
  ///
  /// \code
  ///   { i16 TypeKind, i16 TypeInfo }
  /// \endcode
  ///
  /// followed by an array of i8 containing the type name. TypeKind is 0 for an
  /// integer, 1 for a floating point value, and -1 for anything else.
  llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
    // Only emit each type's descriptor once.
    if (llvm::Constant *C = CGM.getTypeDescriptorFromMap(T))
      return C;
  
    uint16_t TypeKind = -1;
    uint16_t TypeInfo = 0;
  
    if (T->isIntegerType()) {
      TypeKind = 0;
      TypeInfo = (llvm::Log2_32(getContext().getTypeSize(T)) << 1) |
                 (T->isSignedIntegerType() ? 1 : 0);
    } else if (T->isFloatingType()) {
      TypeKind = 1;
      TypeInfo = getContext().getTypeSize(T);
    }
  
    // Format the type name as if for a diagnostic, including quotes and
    // optionally an 'aka'.
    SmallString<32> Buffer;
    CGM.getDiags().ConvertArgToString(DiagnosticsEngine::ak_qualtype,
                                      (intptr_t)T.getAsOpaquePtr(),
                                      StringRef(), StringRef(), None, Buffer,
                                      None);
  
    llvm::Constant *Components[] = {
      Builder.getInt16(TypeKind), Builder.getInt16(TypeInfo),
      llvm::ConstantDataArray::getString(getLLVMContext(), Buffer)
    };
    llvm::Constant *Descriptor = llvm::ConstantStruct::getAnon(Components);
  
    auto *GV = new llvm::GlobalVariable(
        CGM.getModule(), Descriptor->getType(),
        /*isConstant=*/true, llvm::GlobalVariable::PrivateLinkage, Descriptor);
    GV->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
    CGM.getSanitizerMetadata()->disableSanitizerForGlobal(GV);
  
    // Remember the descriptor for this type.
    CGM.setTypeDescriptorInMap(T, GV);
  
    return GV;
  }
  
  llvm::Value *CodeGenFunction::EmitCheckValue(llvm::Value *V) {
    llvm::Type *TargetTy = IntPtrTy;
  
    if (V->getType() == TargetTy)
      return V;
  
    // Floating-point types which fit into intptr_t are bitcast to integers
    // and then passed directly (after zero-extension, if necessary).
    if (V->getType()->isFloatingPointTy()) {
      unsigned Bits = V->getType()->getPrimitiveSizeInBits();
      if (Bits <= TargetTy->getIntegerBitWidth())
        V = Builder.CreateBitCast(V, llvm::Type::getIntNTy(getLLVMContext(),
                                                           Bits));
    }
  
    // Integers which fit in intptr_t are zero-extended and passed directly.
    if (V->getType()->isIntegerTy() &&
        V->getType()->getIntegerBitWidth() <= TargetTy->getIntegerBitWidth())
      return Builder.CreateZExt(V, TargetTy);
  
    // Pointers are passed directly, everything else is passed by address.
    if (!V->getType()->isPointerTy()) {
      Address Ptr = CreateDefaultAlignTempAlloca(V->getType());
      Builder.CreateStore(V, Ptr);
      V = Ptr.getPointer();
    }
    return Builder.CreatePtrToInt(V, TargetTy);
  }
  
  /// Emit a representation of a SourceLocation for passing to a handler
  /// in a sanitizer runtime library. The format for this data is:
  /// \code
  ///   struct SourceLocation {
  ///     const char *Filename;
  ///     int32_t Line, Column;
  ///   };
  /// \endcode
  /// For an invalid SourceLocation, the Filename pointer is null.
  llvm::Constant *CodeGenFunction::EmitCheckSourceLocation(SourceLocation Loc) {
    llvm::Constant *Filename;
    int Line, Column;
  
    PresumedLoc PLoc = getContext().getSourceManager().getPresumedLoc(Loc);
    if (PLoc.isValid()) {
      StringRef FilenameString = PLoc.getFilename();
  
      int PathComponentsToStrip =
          CGM.getCodeGenOpts().EmitCheckPathComponentsToStrip;
      if (PathComponentsToStrip < 0) {
        assert(PathComponentsToStrip != INT_MIN);
        int PathComponentsToKeep = -PathComponentsToStrip;
        auto I = llvm::sys::path::rbegin(FilenameString);
        auto E = llvm::sys::path::rend(FilenameString);
        while (I != E && --PathComponentsToKeep)
          ++I;
  
        FilenameString = FilenameString.substr(I - E);
      } else if (PathComponentsToStrip > 0) {
        auto I = llvm::sys::path::begin(FilenameString);
        auto E = llvm::sys::path::end(FilenameString);
        while (I != E && PathComponentsToStrip--)
          ++I;
  
        if (I != E)
          FilenameString =
              FilenameString.substr(I - llvm::sys::path::begin(FilenameString));
        else
          FilenameString = llvm::sys::path::filename(FilenameString);
      }
  
      auto FilenameGV = CGM.GetAddrOfConstantCString(FilenameString, ".src");
      CGM.getSanitizerMetadata()->disableSanitizerForGlobal(
                            cast<llvm::GlobalVariable>(FilenameGV.getPointer()));
      Filename = FilenameGV.getPointer();
      Line = PLoc.getLine();
      Column = PLoc.getColumn();
    } else {
      Filename = llvm::Constant::getNullValue(Int8PtrTy);
      Line = Column = 0;
    }
  
    llvm::Constant *Data[] = {Filename, Builder.getInt32(Line),
                              Builder.getInt32(Column)};
  
    return llvm::ConstantStruct::getAnon(Data);
  }
  
  namespace {
  /// Specify under what conditions this check can be recovered
  enum class CheckRecoverableKind {
    /// Always terminate program execution if this check fails.
    Unrecoverable,
    /// Check supports recovering, runtime has both fatal (noreturn) and
    /// non-fatal handlers for this check.
    Recoverable,
    /// Runtime conditionally aborts, always need to support recovery.
    AlwaysRecoverable
  };
  }
  
  static CheckRecoverableKind getRecoverableKind(SanitizerMask Kind) {
    assert(llvm::countPopulation(Kind) == 1);
    switch (Kind) {
    case SanitizerKind::Vptr:
      return CheckRecoverableKind::AlwaysRecoverable;
    case SanitizerKind::Return:
    case SanitizerKind::Unreachable:
      return CheckRecoverableKind::Unrecoverable;
    default:
      return CheckRecoverableKind::Recoverable;
    }
  }
  
  namespace {
  struct SanitizerHandlerInfo {
    char const *const Name;
    unsigned Version;
  };
  }
  
  const SanitizerHandlerInfo SanitizerHandlers[] = {
  #define SANITIZER_CHECK(Enum, Name, Version) {#Name, Version},
      LIST_SANITIZER_CHECKS
  #undef SANITIZER_CHECK
  };
  
  static void emitCheckHandlerCall(CodeGenFunction &CGF,
                                   llvm::FunctionType *FnType,
                                   ArrayRef<llvm::Value *> FnArgs,
                                   SanitizerHandler CheckHandler,
                                   CheckRecoverableKind RecoverKind, bool IsFatal,
                                   llvm::BasicBlock *ContBB) {
    assert(IsFatal || RecoverKind != CheckRecoverableKind::Unrecoverable);
    Optional<ApplyDebugLocation> DL;
    if (!CGF.Builder.getCurrentDebugLocation()) {
      // Ensure that the call has at least an artificial debug location.
      DL.emplace(CGF, SourceLocation());
    }
    bool NeedsAbortSuffix =
        IsFatal && RecoverKind != CheckRecoverableKind::Unrecoverable;
    bool MinimalRuntime = CGF.CGM.getCodeGenOpts().SanitizeMinimalRuntime;
    const SanitizerHandlerInfo &CheckInfo = SanitizerHandlers[CheckHandler];
    const StringRef CheckName = CheckInfo.Name;
    std::string FnName = "__ubsan_handle_" + CheckName.str();
    if (CheckInfo.Version && !MinimalRuntime)
      FnName += "_v" + llvm::utostr(CheckInfo.Version);
    if (MinimalRuntime)
      FnName += "_minimal";
    if (NeedsAbortSuffix)
      FnName += "_abort";
    bool MayReturn =
        !IsFatal || RecoverKind == CheckRecoverableKind::AlwaysRecoverable;
  
    llvm::AttrBuilder B;
    if (!MayReturn) {
      B.addAttribute(llvm::Attribute::NoReturn)
          .addAttribute(llvm::Attribute::NoUnwind);
    }
    B.addAttribute(llvm::Attribute::UWTable);
  
    llvm::Value *Fn = CGF.CGM.CreateRuntimeFunction(
        FnType, FnName,
        llvm::AttributeList::get(CGF.getLLVMContext(),
                                 llvm::AttributeList::FunctionIndex, B),
        /*Local=*/true);
    llvm::CallInst *HandlerCall = CGF.EmitNounwindRuntimeCall(Fn, FnArgs);
    if (!MayReturn) {
      HandlerCall->setDoesNotReturn();
      CGF.Builder.CreateUnreachable();
    } else {
      CGF.Builder.CreateBr(ContBB);
    }
  }
  
  void CodeGenFunction::EmitCheck(
      ArrayRef<std::pair<llvm::Value *, SanitizerMask>> Checked,
      SanitizerHandler CheckHandler, ArrayRef<llvm::Constant *> StaticArgs,
      ArrayRef<llvm::Value *> DynamicArgs) {
    assert(IsSanitizerScope);
    assert(Checked.size() > 0);
    assert(CheckHandler >= 0 &&
           size_t(CheckHandler) < llvm::array_lengthof(SanitizerHandlers));
    const StringRef CheckName = SanitizerHandlers[CheckHandler].Name;
  
    llvm::Value *FatalCond = nullptr;
    llvm::Value *RecoverableCond = nullptr;
    llvm::Value *TrapCond = nullptr;
    for (int i = 0, n = Checked.size(); i < n; ++i) {
      llvm::Value *Check = Checked[i].first;
      // -fsanitize-trap= overrides -fsanitize-recover=.
      llvm::Value *&Cond =
          CGM.getCodeGenOpts().SanitizeTrap.has(Checked[i].second)
              ? TrapCond
              : CGM.getCodeGenOpts().SanitizeRecover.has(Checked[i].second)
                    ? RecoverableCond
                    : FatalCond;
      Cond = Cond ? Builder.CreateAnd(Cond, Check) : Check;
    }
  
    if (TrapCond)
      EmitTrapCheck(TrapCond);
    if (!FatalCond && !RecoverableCond)
      return;
  
    llvm::Value *JointCond;
    if (FatalCond && RecoverableCond)
      JointCond = Builder.CreateAnd(FatalCond, RecoverableCond);
    else
      JointCond = FatalCond ? FatalCond : RecoverableCond;
    assert(JointCond);
  
    CheckRecoverableKind RecoverKind = getRecoverableKind(Checked[0].second);
    assert(SanOpts.has(Checked[0].second));
  #ifndef NDEBUG
    for (int i = 1, n = Checked.size(); i < n; ++i) {
      assert(RecoverKind == getRecoverableKind(Checked[i].second) &&
             "All recoverable kinds in a single check must be same!");
      assert(SanOpts.has(Checked[i].second));
    }
  #endif
  
    llvm::BasicBlock *Cont = createBasicBlock("cont");
    llvm::BasicBlock *Handlers = createBasicBlock("handler." + CheckName);
    llvm::Instruction *Branch = Builder.CreateCondBr(JointCond, Cont, Handlers);
    // Give hint that we very much don't expect to execute the handler
    // Value chosen to match UR_NONTAKEN_WEIGHT, see BranchProbabilityInfo.cpp
    llvm::MDBuilder MDHelper(getLLVMContext());
    llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
    Branch->setMetadata(llvm::LLVMContext::MD_prof, Node);
    EmitBlock(Handlers);
  
    // Handler functions take an i8* pointing to the (handler-specific) static
    // information block, followed by a sequence of intptr_t arguments
    // representing operand values.
    SmallVector<llvm::Value *, 4> Args;
    SmallVector<llvm::Type *, 4> ArgTypes;
    if (!CGM.getCodeGenOpts().SanitizeMinimalRuntime) {
      Args.reserve(DynamicArgs.size() + 1);
      ArgTypes.reserve(DynamicArgs.size() + 1);
  
      // Emit handler arguments and create handler function type.
      if (!StaticArgs.empty()) {
        llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
        auto *InfoPtr =
            new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
                                     llvm::GlobalVariable::PrivateLinkage, Info);
        InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
        CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
        Args.push_back(Builder.CreateBitCast(InfoPtr, Int8PtrTy));
        ArgTypes.push_back(Int8PtrTy);
      }
  
      for (size_t i = 0, n = DynamicArgs.size(); i != n; ++i) {
        Args.push_back(EmitCheckValue(DynamicArgs[i]));
        ArgTypes.push_back(IntPtrTy);
      }
    }
  
    llvm::FunctionType *FnType =
      llvm::FunctionType::get(CGM.VoidTy, ArgTypes, false);
  
    if (!FatalCond || !RecoverableCond) {
      // Simple case: we need to generate a single handler call, either
      // fatal, or non-fatal.
      emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind,
                           (FatalCond != nullptr), Cont);
    } else {
      // Emit two handler calls: first one for set of unrecoverable checks,
      // another one for recoverable.
      llvm::BasicBlock *NonFatalHandlerBB =
          createBasicBlock("non_fatal." + CheckName);
      llvm::BasicBlock *FatalHandlerBB = createBasicBlock("fatal." + CheckName);
      Builder.CreateCondBr(FatalCond, NonFatalHandlerBB, FatalHandlerBB);
      EmitBlock(FatalHandlerBB);
      emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, true,
                           NonFatalHandlerBB);
      EmitBlock(NonFatalHandlerBB);
      emitCheckHandlerCall(*this, FnType, Args, CheckHandler, RecoverKind, false,
                           Cont);
    }
  
    EmitBlock(Cont);
  }
  
  void CodeGenFunction::EmitCfiSlowPathCheck(
      SanitizerMask Kind, llvm::Value *Cond, llvm::ConstantInt *TypeId,
      llvm::Value *Ptr, ArrayRef<llvm::Constant *> StaticArgs) {
    llvm::BasicBlock *Cont = createBasicBlock("cfi.cont");
  
    llvm::BasicBlock *CheckBB = createBasicBlock("cfi.slowpath");
    llvm::BranchInst *BI = Builder.CreateCondBr(Cond, Cont, CheckBB);
  
    llvm::MDBuilder MDHelper(getLLVMContext());
    llvm::MDNode *Node = MDHelper.createBranchWeights((1U << 20) - 1, 1);
    BI->setMetadata(llvm::LLVMContext::MD_prof, Node);
  
    EmitBlock(CheckBB);
  
    bool WithDiag = !CGM.getCodeGenOpts().SanitizeTrap.has(Kind);
  
    llvm::CallInst *CheckCall;
    llvm::Constant *SlowPathFn;
    if (WithDiag) {
      llvm::Constant *Info = llvm::ConstantStruct::getAnon(StaticArgs);
      auto *InfoPtr =
          new llvm::GlobalVariable(CGM.getModule(), Info->getType(), false,
                                   llvm::GlobalVariable::PrivateLinkage, Info);
      InfoPtr->setUnnamedAddr(llvm::GlobalValue::UnnamedAddr::Global);
      CGM.getSanitizerMetadata()->disableSanitizerForGlobal(InfoPtr);
  
      SlowPathFn = CGM.getModule().getOrInsertFunction(
          "__cfi_slowpath_diag",
          llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy},
                                  false));
      CheckCall = Builder.CreateCall(
          SlowPathFn, {TypeId, Ptr, Builder.CreateBitCast(InfoPtr, Int8PtrTy)});
    } else {
      SlowPathFn = CGM.getModule().getOrInsertFunction(
          "__cfi_slowpath",
          llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy}, false));
      CheckCall = Builder.CreateCall(SlowPathFn, {TypeId, Ptr});
    }
  
    CGM.setDSOLocal(cast<llvm::GlobalValue>(SlowPathFn->stripPointerCasts()));
    CheckCall->setDoesNotThrow();
  
    EmitBlock(Cont);
  }
  
  // Emit a stub for __cfi_check function so that the linker knows about this
  // symbol in LTO mode.
  void CodeGenFunction::EmitCfiCheckStub() {
    llvm::Module *M = &CGM.getModule();
    auto &Ctx = M->getContext();
    llvm::Function *F = llvm::Function::Create(
        llvm::FunctionType::get(VoidTy, {Int64Ty, Int8PtrTy, Int8PtrTy}, false),
        llvm::GlobalValue::WeakAnyLinkage, "__cfi_check", M);
    CGM.setDSOLocal(F);
    llvm::BasicBlock *BB = llvm::BasicBlock::Create(Ctx, "entry", F);
    // FIXME: consider emitting an intrinsic call like
    // call void @llvm.cfi_check(i64 %0, i8* %1, i8* %2)
    // which can be lowered in CrossDSOCFI pass to the actual contents of
    // __cfi_check. This would allow inlining of __cfi_check calls.
    llvm::CallInst::Create(
        llvm::Intrinsic::getDeclaration(M, llvm::Intrinsic::trap), "", BB);
    llvm::ReturnInst::Create(Ctx, nullptr, BB);
  }
  
  // This function is basically a switch over the CFI failure kind, which is
  // extracted from CFICheckFailData (1st function argument). Each case is either
  // llvm.trap or a call to one of the two runtime handlers, based on
  // -fsanitize-trap and -fsanitize-recover settings.  Default case (invalid
  // failure kind) traps, but this should really never happen.  CFICheckFailData
  // can be nullptr if the calling module has -fsanitize-trap behavior for this
  // check kind; in this case __cfi_check_fail traps as well.
  void CodeGenFunction::EmitCfiCheckFail() {
    SanitizerScope SanScope(this);
    FunctionArgList Args;
    ImplicitParamDecl ArgData(getContext(), getContext().VoidPtrTy,
                              ImplicitParamDecl::Other);
    ImplicitParamDecl ArgAddr(getContext(), getContext().VoidPtrTy,
                              ImplicitParamDecl::Other);
    Args.push_back(&ArgData);
    Args.push_back(&ArgAddr);
  
    const CGFunctionInfo &FI =
      CGM.getTypes().arrangeBuiltinFunctionDeclaration(getContext().VoidTy, Args);
  
    llvm::Function *F = llvm::Function::Create(
        llvm::FunctionType::get(VoidTy, {VoidPtrTy, VoidPtrTy}, false),
        llvm::GlobalValue::WeakODRLinkage, "__cfi_check_fail", &CGM.getModule());
    F->setVisibility(llvm::GlobalValue::HiddenVisibility);
  
    StartFunction(GlobalDecl(), CGM.getContext().VoidTy, F, FI, Args,
                  SourceLocation());
  
    // This function should not be affected by blacklist. This function does
    // not have a source location, but "src:*" would still apply. Revert any
    // changes to SanOpts made in StartFunction.
    SanOpts = CGM.getLangOpts().Sanitize;
  
    llvm::Value *Data =
        EmitLoadOfScalar(GetAddrOfLocalVar(&ArgData), /*Volatile=*/false,
                         CGM.getContext().VoidPtrTy, ArgData.getLocation());
    llvm::Value *Addr =
        EmitLoadOfScalar(GetAddrOfLocalVar(&ArgAddr), /*Volatile=*/false,
                         CGM.getContext().VoidPtrTy, ArgAddr.getLocation());
  
    // Data == nullptr means the calling module has trap behaviour for this check.
    llvm::Value *DataIsNotNullPtr =
        Builder.CreateICmpNE(Data, llvm::ConstantPointerNull::get(Int8PtrTy));
    EmitTrapCheck(DataIsNotNullPtr);
  
    llvm::StructType *SourceLocationTy =
        llvm::StructType::get(VoidPtrTy, Int32Ty, Int32Ty);
    llvm::StructType *CfiCheckFailDataTy =
        llvm::StructType::get(Int8Ty, SourceLocationTy, VoidPtrTy);
  
    llvm::Value *V = Builder.CreateConstGEP2_32(
        CfiCheckFailDataTy,
        Builder.CreatePointerCast(Data, CfiCheckFailDataTy->getPointerTo(0)), 0,
        0);
    Address CheckKindAddr(V, getIntAlign());
    llvm::Value *CheckKind = Builder.CreateLoad(CheckKindAddr);
  
    llvm::Value *AllVtables = llvm::MetadataAsValue::get(
        CGM.getLLVMContext(),
        llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
    llvm::Value *ValidVtable = Builder.CreateZExt(
        Builder.CreateCall(CGM.getIntrinsic(llvm::Intrinsic::type_test),
                           {Addr, AllVtables}),
        IntPtrTy);
  
    const std::pair<int, SanitizerMask> CheckKinds[] = {
        {CFITCK_VCall, SanitizerKind::CFIVCall},
        {CFITCK_NVCall, SanitizerKind::CFINVCall},
        {CFITCK_DerivedCast, SanitizerKind::CFIDerivedCast},
        {CFITCK_UnrelatedCast, SanitizerKind::CFIUnrelatedCast},
        {CFITCK_ICall, SanitizerKind::CFIICall}};
  
    SmallVector<std::pair<llvm::Value *, SanitizerMask>, 5> Checks;
    for (auto CheckKindMaskPair : CheckKinds) {
      int Kind = CheckKindMaskPair.first;
      SanitizerMask Mask = CheckKindMaskPair.second;
      llvm::Value *Cond =
          Builder.CreateICmpNE(CheckKind, llvm::ConstantInt::get(Int8Ty, Kind));
      if (CGM.getLangOpts().Sanitize.has(Mask))
        EmitCheck(std::make_pair(Cond, Mask), SanitizerHandler::CFICheckFail, {},
                  {Data, Addr, ValidVtable});
      else
        EmitTrapCheck(Cond);
    }
  
    FinishFunction();
    // The only reference to this function will be created during LTO link.
    // Make sure it survives until then.
    CGM.addUsedGlobal(F);
  }
  
  void CodeGenFunction::EmitUnreachable(SourceLocation Loc) {
    if (SanOpts.has(SanitizerKind::Unreachable)) {
      SanitizerScope SanScope(this);
      EmitCheck(std::make_pair(static_cast<llvm::Value *>(Builder.getFalse()),
                               SanitizerKind::Unreachable),
                SanitizerHandler::BuiltinUnreachable,
                EmitCheckSourceLocation(Loc), None);
    }
    Builder.CreateUnreachable();
  }
  
  void CodeGenFunction::EmitTrapCheck(llvm::Value *Checked) {
    llvm::BasicBlock *Cont = createBasicBlock("cont");
  
    // If we're optimizing, collapse all calls to trap down to just one per
    // function to save on code size.
    if (!CGM.getCodeGenOpts().OptimizationLevel || !TrapBB) {
      TrapBB = createBasicBlock("trap");
      Builder.CreateCondBr(Checked, Cont, TrapBB);
      EmitBlock(TrapBB);
      llvm::CallInst *TrapCall = EmitTrapCall(llvm::Intrinsic::trap);
      TrapCall->setDoesNotReturn();
      TrapCall->setDoesNotThrow();
      Builder.CreateUnreachable();
    } else {
      Builder.CreateCondBr(Checked, Cont, TrapBB);
    }
  
    EmitBlock(Cont);
  }
  
  llvm::CallInst *CodeGenFunction::EmitTrapCall(llvm::Intrinsic::ID IntrID) {
    llvm::CallInst *TrapCall = Builder.CreateCall(CGM.getIntrinsic(IntrID));
  
    if (!CGM.getCodeGenOpts().TrapFuncName.empty()) {
      auto A = llvm::Attribute::get(getLLVMContext(), "trap-func-name",
                                    CGM.getCodeGenOpts().TrapFuncName);
      TrapCall->addAttribute(llvm::AttributeList::FunctionIndex, A);
    }
  
    return TrapCall;
  }
  
  Address CodeGenFunction::EmitArrayToPointerDecay(const Expr *E,
                                                   LValueBaseInfo *BaseInfo,
                                                   TBAAAccessInfo *TBAAInfo) {
    assert(E->getType()->isArrayType() &&
           "Array to pointer decay must have array source type!");
  
    // Expressions of array type can't be bitfields or vector elements.
    LValue LV = EmitLValue(E);
    Address Addr = LV.getAddress();
  
    // If the array type was an incomplete type, we need to make sure
    // the decay ends up being the right type.
    llvm::Type *NewTy = ConvertType(E->getType());
    Addr = Builder.CreateElementBitCast(Addr, NewTy);
  
    // Note that VLA pointers are always decayed, so we don't need to do
    // anything here.
    if (!E->getType()->isVariableArrayType()) {
      assert(isa<llvm::ArrayType>(Addr.getElementType()) &&
             "Expected pointer to array");
      Addr = Builder.CreateStructGEP(Addr, 0, CharUnits::Zero(), "arraydecay");
    }
  
    // The result of this decay conversion points to an array element within the
    // base lvalue. However, since TBAA currently does not support representing
    // accesses to elements of member arrays, we conservatively represent accesses
    // to the pointee object as if it had no any base lvalue specified.
    // TODO: Support TBAA for member arrays.
    QualType EltType = E->getType()->castAsArrayTypeUnsafe()->getElementType();
    if (BaseInfo) *BaseInfo = LV.getBaseInfo();
    if (TBAAInfo) *TBAAInfo = CGM.getTBAAAccessInfo(EltType);
  
    return Builder.CreateElementBitCast(Addr, ConvertTypeForMem(EltType));
  }
  
  /// isSimpleArrayDecayOperand - If the specified expr is a simple decay from an
  /// array to pointer, return the array subexpression.
  static const Expr *isSimpleArrayDecayOperand(const Expr *E) {
    // If this isn't just an array->pointer decay, bail out.
    const auto *CE = dyn_cast<CastExpr>(E);
    if (!CE || CE->getCastKind() != CK_ArrayToPointerDecay)
      return nullptr;
  
    // If this is a decay from variable width array, bail out.
    const Expr *SubExpr = CE->getSubExpr();
    if (SubExpr->getType()->isVariableArrayType())
      return nullptr;
  
    return SubExpr;
  }
  
  static llvm::Value *emitArraySubscriptGEP(CodeGenFunction &CGF,
                                            llvm::Value *ptr,
                                            ArrayRef<llvm::Value*> indices,
                                            bool inbounds,
                                            bool signedIndices,
                                            SourceLocation loc,
                                      const llvm::Twine &name = "arrayidx") {
    if (inbounds) {
      return CGF.EmitCheckedInBoundsGEP(ptr, indices, signedIndices,
                                        CodeGenFunction::NotSubtraction, loc,
                                        name);
    } else {
      return CGF.Builder.CreateGEP(ptr, indices, name);
    }
  }
  
  static CharUnits getArrayElementAlign(CharUnits arrayAlign,
                                        llvm::Value *idx,
                                        CharUnits eltSize) {
    // If we have a constant index, we can use the exact offset of the
    // element we're accessing.
    if (auto constantIdx = dyn_cast<llvm::ConstantInt>(idx)) {
      CharUnits offset = constantIdx->getZExtValue() * eltSize;
      return arrayAlign.alignmentAtOffset(offset);
  
    // Otherwise, use the worst-case alignment for any element.
    } else {
      return arrayAlign.alignmentOfArrayElement(eltSize);
    }
  }
  
  static QualType getFixedSizeElementType(const ASTContext &ctx,
                                          const VariableArrayType *vla) {
    QualType eltType;
    do {
      eltType = vla->getElementType();
    } while ((vla = ctx.getAsVariableArrayType(eltType)));
    return eltType;
  }
  
  static Address emitArraySubscriptGEP(CodeGenFunction &CGF, Address addr,
                                       ArrayRef<llvm::Value *> indices,
                                       QualType eltType, bool inbounds,
                                       bool signedIndices, SourceLocation loc,
                                       const llvm::Twine &name = "arrayidx") {
    // All the indices except that last must be zero.
  #ifndef NDEBUG
    for (auto idx : indices.drop_back())
      assert(isa<llvm::ConstantInt>(idx) &&
             cast<llvm::ConstantInt>(idx)->isZero());
  #endif
  
    // Determine the element size of the statically-sized base.  This is
    // the thing that the indices are expressed in terms of.
    if (auto vla = CGF.getContext().getAsVariableArrayType(eltType)) {
      eltType = getFixedSizeElementType(CGF.getContext(), vla);
    }
  
    // We can use that to compute the best alignment of the element.
    CharUnits eltSize = CGF.getContext().getTypeSizeInChars(eltType);
    CharUnits eltAlign =
      getArrayElementAlign(addr.getAlignment(), indices.back(), eltSize);
  
    llvm::Value *eltPtr = emitArraySubscriptGEP(
        CGF, addr.getPointer(), indices, inbounds, signedIndices, loc, name);
    return Address(eltPtr, eltAlign);
  }
  
  LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E,
                                                 bool Accessed) {
    // The index must always be an integer, which is not an aggregate.  Emit it
    // in lexical order (this complexity is, sadly, required by C++17).
    llvm::Value *IdxPre =
        (E->getLHS() == E->getIdx()) ? EmitScalarExpr(E->getIdx()) : nullptr;
    bool SignedIndices = false;
    auto EmitIdxAfterBase = [&, IdxPre](bool Promote) -> llvm::Value * {
      auto *Idx = IdxPre;
      if (E->getLHS() != E->getIdx()) {
        assert(E->getRHS() == E->getIdx() && "index was neither LHS nor RHS");
        Idx = EmitScalarExpr(E->getIdx());
      }
  
      QualType IdxTy = E->getIdx()->getType();
      bool IdxSigned = IdxTy->isSignedIntegerOrEnumerationType();
      SignedIndices |= IdxSigned;
  
      if (SanOpts.has(SanitizerKind::ArrayBounds))
        EmitBoundsCheck(E, E->getBase(), Idx, IdxTy, Accessed);
  
      // Extend or truncate the index type to 32 or 64-bits.
      if (Promote && Idx->getType() != IntPtrTy)
        Idx = Builder.CreateIntCast(Idx, IntPtrTy, IdxSigned, "idxprom");
  
      return Idx;
    };
    IdxPre = nullptr;
  
    // If the base is a vector type, then we are forming a vector element lvalue
    // with this subscript.
    if (E->getBase()->getType()->isVectorType() &&
        !isa<ExtVectorElementExpr>(E->getBase())) {
      // Emit the vector as an lvalue to get its address.
      LValue LHS = EmitLValue(E->getBase());
      auto *Idx = EmitIdxAfterBase(/*Promote*/false);
      assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
      return LValue::MakeVectorElt(LHS.getAddress(), Idx, E->getBase()->getType(),
                                   LHS.getBaseInfo(), TBAAAccessInfo());
    }
  
    // All the other cases basically behave like simple offsetting.
  
    // Handle the extvector case we ignored above.
    if (isa<ExtVectorElementExpr>(E->getBase())) {
      LValue LV = EmitLValue(E->getBase());
      auto *Idx = EmitIdxAfterBase(/*Promote*/true);
      Address Addr = EmitExtVectorElementLValue(LV);
  
      QualType EltType = LV.getType()->castAs<VectorType>()->getElementType();
      Addr = emitArraySubscriptGEP(*this, Addr, Idx, EltType, /*inbounds*/ true,
                                   SignedIndices, E->getExprLoc());
      return MakeAddrLValue(Addr, EltType, LV.getBaseInfo(),
                            CGM.getTBAAInfoForSubobject(LV, EltType));
    }
  
    LValueBaseInfo EltBaseInfo;
    TBAAAccessInfo EltTBAAInfo;
    Address Addr = Address::invalid();
    if (const VariableArrayType *vla =
             getContext().getAsVariableArrayType(E->getType())) {
      // The base must be a pointer, which is not an aggregate.  Emit
      // it.  It needs to be emitted first in case it's what captures
      // the VLA bounds.
      Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
      auto *Idx = EmitIdxAfterBase(/*Promote*/true);
  
      // The element count here is the total number of non-VLA elements.
      llvm::Value *numElements = getVLASize(vla).NumElts;
  
      // Effectively, the multiply by the VLA size is part of the GEP.
      // GEP indexes are signed, and scaling an index isn't permitted to
      // signed-overflow, so we use the same semantics for our explicit
      // multiply.  We suppress this if overflow is not undefined behavior.
      if (getLangOpts().isSignedOverflowDefined()) {
        Idx = Builder.CreateMul(Idx, numElements);
      } else {
        Idx = Builder.CreateNSWMul(Idx, numElements);
      }
  
      Addr = emitArraySubscriptGEP(*this, Addr, Idx, vla->getElementType(),
                                   !getLangOpts().isSignedOverflowDefined(),
                                   SignedIndices, E->getExprLoc());
  
    } else if (const ObjCObjectType *OIT = E->getType()->getAs<ObjCObjectType>()){
      // Indexing over an interface, as in "NSString *P; P[4];"
  
      // Emit the base pointer.
      Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
      auto *Idx = EmitIdxAfterBase(/*Promote*/true);
  
      CharUnits InterfaceSize = getContext().getTypeSizeInChars(OIT);
      llvm::Value *InterfaceSizeVal =
          llvm::ConstantInt::get(Idx->getType(), InterfaceSize.getQuantity());
  
      llvm::Value *ScaledIdx = Builder.CreateMul(Idx, InterfaceSizeVal);
  
      // We don't necessarily build correct LLVM struct types for ObjC
      // interfaces, so we can't rely on GEP to do this scaling
      // correctly, so we need to cast to i8*.  FIXME: is this actually
      // true?  A lot of other things in the fragile ABI would break...
      llvm::Type *OrigBaseTy = Addr.getType();
      Addr = Builder.CreateElementBitCast(Addr, Int8Ty);
  
      // Do the GEP.
      CharUnits EltAlign =
        getArrayElementAlign(Addr.getAlignment(), Idx, InterfaceSize);
      llvm::Value *EltPtr =
          emitArraySubscriptGEP(*this, Addr.getPointer(), ScaledIdx, false,
                                SignedIndices, E->getExprLoc());
      Addr = Address(EltPtr, EltAlign);
  
      // Cast back.
      Addr = Builder.CreateBitCast(Addr, OrigBaseTy);
    } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
      // If this is A[i] where A is an array, the frontend will have decayed the
      // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
      // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
      // "gep x, i" here.  Emit one "gep A, 0, i".
      assert(Array->getType()->isArrayType() &&
             "Array to pointer decay must have array source type!");
      LValue ArrayLV;
      // For simple multidimensional array indexing, set the 'accessed' flag for
      // better bounds-checking of the base expression.
      if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Array))
        ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
      else
        ArrayLV = EmitLValue(Array);
      auto *Idx = EmitIdxAfterBase(/*Promote*/true);
  
      // Propagate the alignment from the array itself to the result.
      Addr = emitArraySubscriptGEP(
          *this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx},
          E->getType(), !getLangOpts().isSignedOverflowDefined(), SignedIndices,
          E->getExprLoc());
      EltBaseInfo = ArrayLV.getBaseInfo();
      EltTBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, E->getType());
    } else {
      // The base must be a pointer; emit it with an estimate of its alignment.
      Addr = EmitPointerWithAlignment(E->getBase(), &EltBaseInfo, &EltTBAAInfo);
      auto *Idx = EmitIdxAfterBase(/*Promote*/true);
      Addr = emitArraySubscriptGEP(*this, Addr, Idx, E->getType(),
                                   !getLangOpts().isSignedOverflowDefined(),
                                   SignedIndices, E->getExprLoc());
    }
  
    LValue LV = MakeAddrLValue(Addr, E->getType(), EltBaseInfo, EltTBAAInfo);
  
    if (getLangOpts().ObjC &&
        getLangOpts().getGC() != LangOptions::NonGC) {
      LV.setNonGC(!E->isOBJCGCCandidate(getContext()));
      setObjCGCLValueClass(getContext(), E, LV);
    }
    return LV;
  }
  
  static Address emitOMPArraySectionBase(CodeGenFunction &CGF, const Expr *Base,
                                         LValueBaseInfo &BaseInfo,
                                         TBAAAccessInfo &TBAAInfo,
                                         QualType BaseTy, QualType ElTy,
                                         bool IsLowerBound) {
    LValue BaseLVal;
    if (auto *ASE = dyn_cast<OMPArraySectionExpr>(Base->IgnoreParenImpCasts())) {
      BaseLVal = CGF.EmitOMPArraySectionExpr(ASE, IsLowerBound);
      if (BaseTy->isArrayType()) {
        Address Addr = BaseLVal.getAddress();
        BaseInfo = BaseLVal.getBaseInfo();
  
        // If the array type was an incomplete type, we need to make sure
        // the decay ends up being the right type.
        llvm::Type *NewTy = CGF.ConvertType(BaseTy);
        Addr = CGF.Builder.CreateElementBitCast(Addr, NewTy);
  
        // Note that VLA pointers are always decayed, so we don't need to do
        // anything here.
        if (!BaseTy->isVariableArrayType()) {
          assert(isa<llvm::ArrayType>(Addr.getElementType()) &&
                 "Expected pointer to array");
          Addr = CGF.Builder.CreateStructGEP(Addr, 0, CharUnits::Zero(),
                                             "arraydecay");
        }
  
        return CGF.Builder.CreateElementBitCast(Addr,
                                                CGF.ConvertTypeForMem(ElTy));
      }
      LValueBaseInfo TypeBaseInfo;
      TBAAAccessInfo TypeTBAAInfo;
      CharUnits Align = CGF.getNaturalTypeAlignment(ElTy, &TypeBaseInfo,
                                                    &TypeTBAAInfo);
      BaseInfo.mergeForCast(TypeBaseInfo);
      TBAAInfo = CGF.CGM.mergeTBAAInfoForCast(TBAAInfo, TypeTBAAInfo);
      return Address(CGF.Builder.CreateLoad(BaseLVal.getAddress()), Align);
    }
    return CGF.EmitPointerWithAlignment(Base, &BaseInfo, &TBAAInfo);
  }
  
  LValue CodeGenFunction::EmitOMPArraySectionExpr(const OMPArraySectionExpr *E,
                                                  bool IsLowerBound) {
    QualType BaseTy = OMPArraySectionExpr::getBaseOriginalType(E->getBase());
    QualType ResultExprTy;
    if (auto *AT = getContext().getAsArrayType(BaseTy))
      ResultExprTy = AT->getElementType();
    else
      ResultExprTy = BaseTy->getPointeeType();
    llvm::Value *Idx = nullptr;
    if (IsLowerBound || E->getColonLoc().isInvalid()) {
      // Requesting lower bound or upper bound, but without provided length and
      // without ':' symbol for the default length -> length = 1.
      // Idx = LowerBound ?: 0;
      if (auto *LowerBound = E->getLowerBound()) {
        Idx = Builder.CreateIntCast(
            EmitScalarExpr(LowerBound), IntPtrTy,
            LowerBound->getType()->hasSignedIntegerRepresentation());
      } else
        Idx = llvm::ConstantInt::getNullValue(IntPtrTy);
    } else {
      // Try to emit length or lower bound as constant. If this is possible, 1
      // is subtracted from constant length or lower bound. Otherwise, emit LLVM
      // IR (LB + Len) - 1.
      auto &C = CGM.getContext();
      auto *Length = E->getLength();
      llvm::APSInt ConstLength;
      if (Length) {
        // Idx = LowerBound + Length - 1;
        if (Length->isIntegerConstantExpr(ConstLength, C)) {
          ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits);
          Length = nullptr;
        }
        auto *LowerBound = E->getLowerBound();
        llvm::APSInt ConstLowerBound(PointerWidthInBits, /*isUnsigned=*/false);
        if (LowerBound && LowerBound->isIntegerConstantExpr(ConstLowerBound, C)) {
          ConstLowerBound = ConstLowerBound.zextOrTrunc(PointerWidthInBits);
          LowerBound = nullptr;
        }
        if (!Length)
          --ConstLength;
        else if (!LowerBound)
          --ConstLowerBound;
  
        if (Length || LowerBound) {
          auto *LowerBoundVal =
              LowerBound
                  ? Builder.CreateIntCast(
                        EmitScalarExpr(LowerBound), IntPtrTy,
                        LowerBound->getType()->hasSignedIntegerRepresentation())
                  : llvm::ConstantInt::get(IntPtrTy, ConstLowerBound);
          auto *LengthVal =
              Length
                  ? Builder.CreateIntCast(
                        EmitScalarExpr(Length), IntPtrTy,
                        Length->getType()->hasSignedIntegerRepresentation())
                  : llvm::ConstantInt::get(IntPtrTy, ConstLength);
          Idx = Builder.CreateAdd(LowerBoundVal, LengthVal, "lb_add_len",
                                  /*HasNUW=*/false,
                                  !getLangOpts().isSignedOverflowDefined());
          if (Length && LowerBound) {
            Idx = Builder.CreateSub(
                Idx, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "idx_sub_1",
                /*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined());
          }
        } else
          Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength + ConstLowerBound);
      } else {
        // Idx = ArraySize - 1;
        QualType ArrayTy = BaseTy->isPointerType()
                               ? E->getBase()->IgnoreParenImpCasts()->getType()
                               : BaseTy;
        if (auto *VAT = C.getAsVariableArrayType(ArrayTy)) {
          Length = VAT->getSizeExpr();
          if (Length->isIntegerConstantExpr(ConstLength, C))
            Length = nullptr;
        } else {
          auto *CAT = C.getAsConstantArrayType(ArrayTy);
          ConstLength = CAT->getSize();
        }
        if (Length) {
          auto *LengthVal = Builder.CreateIntCast(
              EmitScalarExpr(Length), IntPtrTy,
              Length->getType()->hasSignedIntegerRepresentation());
          Idx = Builder.CreateSub(
              LengthVal, llvm::ConstantInt::get(IntPtrTy, /*V=*/1), "len_sub_1",
              /*HasNUW=*/false, !getLangOpts().isSignedOverflowDefined());
        } else {
          ConstLength = ConstLength.zextOrTrunc(PointerWidthInBits);
          --ConstLength;
          Idx = llvm::ConstantInt::get(IntPtrTy, ConstLength);
        }
      }
    }
    assert(Idx);
  
    Address EltPtr = Address::invalid();
    LValueBaseInfo BaseInfo;
    TBAAAccessInfo TBAAInfo;
    if (auto *VLA = getContext().getAsVariableArrayType(ResultExprTy)) {
      // The base must be a pointer, which is not an aggregate.  Emit
      // it.  It needs to be emitted first in case it's what captures
      // the VLA bounds.
      Address Base =
          emitOMPArraySectionBase(*this, E->getBase(), BaseInfo, TBAAInfo,
                                  BaseTy, VLA->getElementType(), IsLowerBound);
      // The element count here is the total number of non-VLA elements.
      llvm::Value *NumElements = getVLASize(VLA).NumElts;
  
      // Effectively, the multiply by the VLA size is part of the GEP.
      // GEP indexes are signed, and scaling an index isn't permitted to
      // signed-overflow, so we use the same semantics for our explicit
      // multiply.  We suppress this if overflow is not undefined behavior.
      if (getLangOpts().isSignedOverflowDefined())
        Idx = Builder.CreateMul(Idx, NumElements);
      else
        Idx = Builder.CreateNSWMul(Idx, NumElements);
      EltPtr = emitArraySubscriptGEP(*this, Base, Idx, VLA->getElementType(),
                                     !getLangOpts().isSignedOverflowDefined(),
                                     /*SignedIndices=*/false, E->getExprLoc());
    } else if (const Expr *Array = isSimpleArrayDecayOperand(E->getBase())) {
      // If this is A[i] where A is an array, the frontend will have decayed the
      // base to be a ArrayToPointerDecay implicit cast.  While correct, it is
      // inefficient at -O0 to emit a "gep A, 0, 0" when codegen'ing it, then a
      // "gep x, i" here.  Emit one "gep A, 0, i".
      assert(Array->getType()->isArrayType() &&
             "Array to pointer decay must have array source type!");
      LValue ArrayLV;
      // For simple multidimensional array indexing, set the 'accessed' flag for
      // better bounds-checking of the base expression.
      if (const auto *ASE = dyn_cast<ArraySubscriptExpr>(Array))
        ArrayLV = EmitArraySubscriptExpr(ASE, /*Accessed*/ true);
      else
        ArrayLV = EmitLValue(Array);
  
      // Propagate the alignment from the array itself to the result.
      EltPtr = emitArraySubscriptGEP(
          *this, ArrayLV.getAddress(), {CGM.getSize(CharUnits::Zero()), Idx},
          ResultExprTy, !getLangOpts().isSignedOverflowDefined(),
          /*SignedIndices=*/false, E->getExprLoc());
      BaseInfo = ArrayLV.getBaseInfo();
      TBAAInfo = CGM.getTBAAInfoForSubobject(ArrayLV, ResultExprTy);
    } else {
      Address Base = emitOMPArraySectionBase(*this, E->getBase(), BaseInfo,
                                             TBAAInfo, BaseTy, ResultExprTy,
                                             IsLowerBound);
      EltPtr = emitArraySubscriptGEP(*this, Base, Idx, ResultExprTy,
                                     !getLangOpts().isSignedOverflowDefined(),
                                     /*SignedIndices=*/false, E->getExprLoc());
    }
  
    return MakeAddrLValue(EltPtr, ResultExprTy, BaseInfo, TBAAInfo);
  }
  
  LValue CodeGenFunction::
  EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
    // Emit the base vector as an l-value.
    LValue Base;
  
    // ExtVectorElementExpr's base can either be a vector or pointer to vector.
    if (E->isArrow()) {
      // If it is a pointer to a vector, emit the address and form an lvalue with
      // it.
      LValueBaseInfo BaseInfo;
      TBAAAccessInfo TBAAInfo;
      Address Ptr = EmitPointerWithAlignment(E->getBase(), &BaseInfo, &TBAAInfo);
      const PointerType *PT = E->getBase()->getType()->getAs<PointerType>();
      Base = MakeAddrLValue(Ptr, PT->getPointeeType(), BaseInfo, TBAAInfo);
      Base.getQuals().removeObjCGCAttr();
    } else if (E->getBase()->isGLValue()) {
      // Otherwise, if the base is an lvalue ( as in the case of foo.x.x),
      // emit the base as an lvalue.
      assert(E->getBase()->getType()->isVectorType());
      Base = EmitLValue(E->getBase());
    } else {
      // Otherwise, the base is a normal rvalue (as in (V+V).x), emit it as such.
      assert(E->getBase()->getType()->isVectorType() &&
             "Result must be a vector");
      llvm::Value *Vec = EmitScalarExpr(E->getBase());
  
      // Store the vector to memory (because LValue wants an address).
      Address VecMem = CreateMemTemp(E->getBase()->getType());
      Builder.CreateStore(Vec, VecMem);
      Base = MakeAddrLValue(VecMem, E->getBase()->getType(),
                            AlignmentSource::Decl);
    }
  
    QualType type =
      E->getType().withCVRQualifiers(Base.getQuals().getCVRQualifiers());
  
    // Encode the element access list into a vector of unsigned indices.
    SmallVector<uint32_t, 4> Indices;
    E->getEncodedElementAccess(Indices);
  
    if (Base.isSimple()) {
      llvm::Constant *CV =
          llvm::ConstantDataVector::get(getLLVMContext(), Indices);
      return LValue::MakeExtVectorElt(Base.getAddress(), CV, type,
                                      Base.getBaseInfo(), TBAAAccessInfo());
    }
    assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
  
    llvm::Constant *BaseElts = Base.getExtVectorElts();
    SmallVector<llvm::Constant *, 4> CElts;
  
    for (unsigned i = 0, e = Indices.size(); i != e; ++i)
      CElts.push_back(BaseElts->getAggregateElement(Indices[i]));
    llvm::Constant *CV = llvm::ConstantVector::get(CElts);
    return LValue::MakeExtVectorElt(Base.getExtVectorAddress(), CV, type,
                                    Base.getBaseInfo(), TBAAAccessInfo());
  }
  
  LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
    if (DeclRefExpr *DRE = tryToConvertMemberExprToDeclRefExpr(*this, E)) {
      EmitIgnoredExpr(E->getBase());
      return EmitDeclRefLValue(DRE);
    }
  
    Expr *BaseExpr = E->getBase();
    // If this is s.x, emit s as an lvalue.  If it is s->x, emit s as a scalar.
    LValue BaseLV;
    if (E->isArrow()) {
      LValueBaseInfo BaseInfo;
      TBAAAccessInfo TBAAInfo;
      Address Addr = EmitPointerWithAlignment(BaseExpr, &BaseInfo, &TBAAInfo);
      QualType PtrTy = BaseExpr->getType()->getPointeeType();
      SanitizerSet SkippedChecks;
      bool IsBaseCXXThis = IsWrappedCXXThis(BaseExpr);
      if (IsBaseCXXThis)
        SkippedChecks.set(SanitizerKind::Alignment, true);
      if (IsBaseCXXThis || isa<DeclRefExpr>(BaseExpr))
        SkippedChecks.set(SanitizerKind::Null, true);
      EmitTypeCheck(TCK_MemberAccess, E->getExprLoc(), Addr.getPointer(), PtrTy,
                    /*Alignment=*/CharUnits::Zero(), SkippedChecks);
      BaseLV = MakeAddrLValue(Addr, PtrTy, BaseInfo, TBAAInfo);
    } else
      BaseLV = EmitCheckedLValue(BaseExpr, TCK_MemberAccess);
  
    NamedDecl *ND = E->getMemberDecl();
    if (auto *Field = dyn_cast<FieldDecl>(ND)) {
      LValue LV = EmitLValueForField(BaseLV, Field);
      setObjCGCLValueClass(getContext(), E, LV);
      return LV;
    }
  
    if (const auto *FD = dyn_cast<FunctionDecl>(ND))
      return EmitFunctionDeclLValue(*this, E, FD);
  
    llvm_unreachable("Unhandled member declaration!");
  }
  
  /// Given that we are currently emitting a lambda, emit an l-value for
  /// one of its members.
  LValue CodeGenFunction::EmitLValueForLambdaField(const FieldDecl *Field) {
    assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent()->isLambda());
    assert(cast<CXXMethodDecl>(CurCodeDecl)->getParent() == Field->getParent());
    QualType LambdaTagType =
      getContext().getTagDeclType(Field->getParent());
    LValue LambdaLV = MakeNaturalAlignAddrLValue(CXXABIThisValue, LambdaTagType);
    return EmitLValueForField(LambdaLV, Field);
  }
  
  /// Drill down to the storage of a field without walking into
  /// reference types.
  ///
  /// The resulting address doesn't necessarily have the right type.
  static Address emitAddrOfFieldStorage(CodeGenFunction &CGF, Address base,
                                        const FieldDecl *field) {
    const RecordDecl *rec = field->getParent();
  
    unsigned idx =
      CGF.CGM.getTypes().getCGRecordLayout(rec).getLLVMFieldNo(field);
  
    CharUnits offset;
    // Adjust the alignment down to the given offset.
    // As a special case, if the LLVM field index is 0, we know that this
    // is zero.
    assert((idx != 0 || CGF.getContext().getASTRecordLayout(rec)
                           .getFieldOffset(field->getFieldIndex()) == 0) &&
           "LLVM field at index zero had non-zero offset?");
    if (idx != 0) {
      auto &recLayout = CGF.getContext().getASTRecordLayout(rec);
      auto offsetInBits = recLayout.getFieldOffset(field->getFieldIndex());
      offset = CGF.getContext().toCharUnitsFromBits(offsetInBits);
    }
  
    return CGF.Builder.CreateStructGEP(base, idx, offset, field->getName());
  }
  
  static bool hasAnyVptr(const QualType Type, const ASTContext &Context) {
    const auto *RD = Type.getTypePtr()->getAsCXXRecordDecl();
    if (!RD)
      return false;
  
    if (RD->isDynamicClass())
      return true;
  
    for (const auto &Base : RD->bases())
      if (hasAnyVptr(Base.getType(), Context))
        return true;
  
    for (const FieldDecl *Field : RD->fields())
      if (hasAnyVptr(Field->getType(), Context))
        return true;
  
    return false;
  }
  
  LValue CodeGenFunction::EmitLValueForField(LValue base,
                                             const FieldDecl *field) {
    LValueBaseInfo BaseInfo = base.getBaseInfo();
  
    if (field->isBitField()) {
      const CGRecordLayout &RL =
        CGM.getTypes().getCGRecordLayout(field->getParent());
      const CGBitFieldInfo &Info = RL.getBitFieldInfo(field);
      Address Addr = base.getAddress();
      unsigned Idx = RL.getLLVMFieldNo(field);
      if (Idx != 0)
        // For structs, we GEP to the field that the record layout suggests.
        Addr = Builder.CreateStructGEP(Addr, Idx, Info.StorageOffset,
                                       field->getName());
      // Get the access type.
      llvm::Type *FieldIntTy =
        llvm::Type::getIntNTy(getLLVMContext(), Info.StorageSize);
      if (Addr.getElementType() != FieldIntTy)
        Addr = Builder.CreateElementBitCast(Addr, FieldIntTy);
  
      QualType fieldType =
        field->getType().withCVRQualifiers(base.getVRQualifiers());
      // TODO: Support TBAA for bit fields.
      LValueBaseInfo FieldBaseInfo(BaseInfo.getAlignmentSource());
      return LValue::MakeBitfield(Addr, Info, fieldType, FieldBaseInfo,
                                  TBAAAccessInfo());
    }
  
    // Fields of may-alias structures are may-alias themselves.
    // FIXME: this should get propagated down through anonymous structs
    // and unions.
    QualType FieldType = field->getType();
    const RecordDecl *rec = field->getParent();
    AlignmentSource BaseAlignSource = BaseInfo.getAlignmentSource();
    LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(BaseAlignSource));
    TBAAAccessInfo FieldTBAAInfo;
    if (base.getTBAAInfo().isMayAlias() ||
            rec->hasAttr<MayAliasAttr>() || FieldType->isVectorType()) {
      FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
    } else if (rec->isUnion()) {
      // TODO: Support TBAA for unions.
      FieldTBAAInfo = TBAAAccessInfo::getMayAliasInfo();
    } else {
      // If no base type been assigned for the base access, then try to generate
      // one for this base lvalue.
      FieldTBAAInfo = base.getTBAAInfo();
      if (!FieldTBAAInfo.BaseType) {
          FieldTBAAInfo.BaseType = CGM.getTBAABaseTypeInfo(base.getType());
          assert(!FieldTBAAInfo.Offset &&
                 "Nonzero offset for an access with no base type!");
      }
  
      // Adjust offset to be relative to the base type.
      const ASTRecordLayout &Layout =
          getContext().getASTRecordLayout(field->getParent());
      unsigned CharWidth = getContext().getCharWidth();
      if (FieldTBAAInfo.BaseType)
        FieldTBAAInfo.Offset +=
            Layout.getFieldOffset(field->getFieldIndex()) / CharWidth;
  
      // Update the final access type and size.
      FieldTBAAInfo.AccessType = CGM.getTBAATypeInfo(FieldType);
      FieldTBAAInfo.Size =
          getContext().getTypeSizeInChars(FieldType).getQuantity();
    }
  
    Address addr = base.getAddress();
    if (auto *ClassDef = dyn_cast<CXXRecordDecl>(rec)) {
      if (CGM.getCodeGenOpts().StrictVTablePointers &&
          ClassDef->isDynamicClass()) {
        // Getting to any field of dynamic object requires stripping dynamic
        // information provided by invariant.group.  This is because accessing
        // fields may leak the real address of dynamic object, which could result
        // in miscompilation when leaked pointer would be compared.
        auto *stripped = Builder.CreateStripInvariantGroup(addr.getPointer());
        addr = Address(stripped, addr.getAlignment());
      }
    }
  
    unsigned RecordCVR = base.getVRQualifiers();
    if (rec->isUnion()) {
      // For unions, there is no pointer adjustment.
      assert(!FieldType->isReferenceType() && "union has reference member");
      if (CGM.getCodeGenOpts().StrictVTablePointers &&
          hasAnyVptr(FieldType, getContext()))
        // Because unions can easily skip invariant.barriers, we need to add
        // a barrier every time CXXRecord field with vptr is referenced.
        addr = Address(Builder.CreateLaunderInvariantGroup(addr.getPointer()),
                       addr.getAlignment());
    } else {
      // For structs, we GEP to the field that the record layout suggests.
      addr = emitAddrOfFieldStorage(*this, addr, field);
  
      // If this is a reference field, load the reference right now.
      if (FieldType->isReferenceType()) {
        LValue RefLVal = MakeAddrLValue(addr, FieldType, FieldBaseInfo,
                                        FieldTBAAInfo);
        if (RecordCVR & Qualifiers::Volatile)
          RefLVal.getQuals().addVolatile();
        addr = EmitLoadOfReference(RefLVal, &FieldBaseInfo, &FieldTBAAInfo);
  
        // Qualifiers on the struct don't apply to the referencee.
        RecordCVR = 0;
        FieldType = FieldType->getPointeeType();
      }
    }
  
    // Make sure that the address is pointing to the right type.  This is critical
    // for both unions and structs.  A union needs a bitcast, a struct element
    // will need a bitcast if the LLVM type laid out doesn't match the desired
    // type.
    addr = Builder.CreateElementBitCast(
        addr, CGM.getTypes().ConvertTypeForMem(FieldType), field->getName());
  
    if (field->hasAttr<AnnotateAttr>())
      addr = EmitFieldAnnotations(field, addr);
  
    LValue LV = MakeAddrLValue(addr, FieldType, FieldBaseInfo, FieldTBAAInfo);
    LV.getQuals().addCVRQualifiers(RecordCVR);
  
    // __weak attribute on a field is ignored.
    if (LV.getQuals().getObjCGCAttr() == Qualifiers::Weak)
      LV.getQuals().removeObjCGCAttr();
  
    return LV;
  }
  
  LValue
  CodeGenFunction::EmitLValueForFieldInitialization(LValue Base,
                                                    const FieldDecl *Field) {
    QualType FieldType = Field->getType();
  
    if (!FieldType->isReferenceType())
      return EmitLValueForField(Base, Field);
  
    Address V = emitAddrOfFieldStorage(*this, Base.getAddress(), Field);
  
    // Make sure that the address is pointing to the right type.
    llvm::Type *llvmType = ConvertTypeForMem(FieldType);
    V = Builder.CreateElementBitCast(V, llvmType, Field->getName());
  
    // TODO: Generate TBAA information that describes this access as a structure
    // member access and not just an access to an object of the field's type. This
    // should be similar to what we do in EmitLValueForField().
    LValueBaseInfo BaseInfo = Base.getBaseInfo();
    AlignmentSource FieldAlignSource = BaseInfo.getAlignmentSource();
    LValueBaseInfo FieldBaseInfo(getFieldAlignmentSource(FieldAlignSource));
    return MakeAddrLValue(V, FieldType, FieldBaseInfo,
                          CGM.getTBAAInfoForSubobject(Base, FieldType));
  }
  
  LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr *E){
    if (E->isFileScope()) {
      ConstantAddress GlobalPtr = CGM.GetAddrOfConstantCompoundLiteral(E);
      return MakeAddrLValue(GlobalPtr, E->getType(), AlignmentSource::Decl);
    }
    if (E->getType()->isVariablyModifiedType())
      // make sure to emit the VLA size.
      EmitVariablyModifiedType(E->getType());
  
    Address DeclPtr = CreateMemTemp(E->getType(), ".compoundliteral");
    const Expr *InitExpr = E->getInitializer();
    LValue Result = MakeAddrLValue(DeclPtr, E->getType(), AlignmentSource::Decl);
  
    EmitAnyExprToMem(InitExpr, DeclPtr, E->getType().getQualifiers(),
                     /*Init*/ true);
  
    return Result;
  }
  
  LValue CodeGenFunction::EmitInitListLValue(const InitListExpr *E) {
    if (!E->isGLValue())
      // Initializing an aggregate temporary in C++11: T{...}.
      return EmitAggExprToLValue(E);
  
    // An lvalue initializer list must be initializing a reference.
    assert(E->isTransparent() && "non-transparent glvalue init list");
    return EmitLValue(E->getInit(0));
  }
  
  /// Emit the operand of a glvalue conditional operator. This is either a glvalue
  /// or a (possibly-parenthesized) throw-expression. If this is a throw, no
  /// LValue is returned and the current block has been terminated.
  static Optional<LValue> EmitLValueOrThrowExpression(CodeGenFunction &CGF,
                                                      const Expr *Operand) {
    if (auto *ThrowExpr = dyn_cast<CXXThrowExpr>(Operand->IgnoreParens())) {
      CGF.EmitCXXThrowExpr(ThrowExpr, /*KeepInsertionPoint*/false);
      return None;
    }
  
    return CGF.EmitLValue(Operand);
  }
  
  LValue CodeGenFunction::
  EmitConditionalOperatorLValue(const AbstractConditionalOperator *expr) {
    if (!expr->isGLValue()) {
      // ?: here should be an aggregate.
      assert(hasAggregateEvaluationKind(expr->getType()) &&
             "Unexpected conditional operator!");
      return EmitAggExprToLValue(expr);
    }
  
    OpaqueValueMapping binding(*this, expr);
  
    const Expr *condExpr = expr->getCond();
    bool CondExprBool;
    if (ConstantFoldsToSimpleInteger(condExpr, CondExprBool)) {
      const Expr *live = expr->getTrueExpr(), *dead = expr->getFalseExpr();
      if (!CondExprBool) std::swap(live, dead);
  
      if (!ContainsLabel(dead)) {
        // If the true case is live, we need to track its region.
        if (CondExprBool)
          incrementProfileCounter(expr);
        return EmitLValue(live);
      }
    }
  
    llvm::BasicBlock *lhsBlock = createBasicBlock("cond.true");
    llvm::BasicBlock *rhsBlock = createBasicBlock("cond.false");
    llvm::BasicBlock *contBlock = createBasicBlock("cond.end");
  
    ConditionalEvaluation eval(*this);
    EmitBranchOnBoolExpr(condExpr, lhsBlock, rhsBlock, getProfileCount(expr));
  
    // Any temporaries created here are conditional.
    EmitBlock(lhsBlock);
    incrementProfileCounter(expr);
    eval.begin(*this);
    Optional<LValue> lhs =
        EmitLValueOrThrowExpression(*this, expr->getTrueExpr());
    eval.end(*this);
  
    if (lhs && !lhs->isSimple())
      return EmitUnsupportedLValue(expr, "conditional operator");
  
    lhsBlock = Builder.GetInsertBlock();
    if (lhs)
      Builder.CreateBr(contBlock);
  
    // Any temporaries created here are conditional.
    EmitBlock(rhsBlock);
    eval.begin(*this);
    Optional<LValue> rhs =
        EmitLValueOrThrowExpression(*this, expr->getFalseExpr());
    eval.end(*this);
    if (rhs && !rhs->isSimple())
      return EmitUnsupportedLValue(expr, "conditional operator");
    rhsBlock = Builder.GetInsertBlock();
  
    EmitBlock(contBlock);
  
    if (lhs && rhs) {
      llvm::PHINode *phi = Builder.CreatePHI(lhs->getPointer()->getType(),
                                             2, "cond-lvalue");
      phi->addIncoming(lhs->getPointer(), lhsBlock);
      phi->addIncoming(rhs->getPointer(), rhsBlock);
      Address result(phi, std::min(lhs->getAlignment(), rhs->getAlignment()));
      AlignmentSource alignSource =
        std::max(lhs->getBaseInfo().getAlignmentSource(),
                 rhs->getBaseInfo().getAlignmentSource());
      TBAAAccessInfo TBAAInfo = CGM.mergeTBAAInfoForConditionalOperator(
          lhs->getTBAAInfo(), rhs->getTBAAInfo());
      return MakeAddrLValue(result, expr->getType(), LValueBaseInfo(alignSource),
                            TBAAInfo);
    } else {
      assert((lhs || rhs) &&
             "both operands of glvalue conditional are throw-expressions?");
      return lhs ? *lhs : *rhs;
    }
  }
  
  /// EmitCastLValue - Casts are never lvalues unless that cast is to a reference
  /// type. If the cast is to a reference, we can have the usual lvalue result,
  /// otherwise if a cast is needed by the code generator in an lvalue context,
  /// then it must mean that we need the address of an aggregate in order to
  /// access one of its members.  This can happen for all the reasons that casts
  /// are permitted with aggregate result, including noop aggregate casts, and
  /// cast from scalar to union.
  LValue CodeGenFunction::EmitCastLValue(const CastExpr *E) {
    switch (E->getCastKind()) {
    case CK_ToVoid:
    case CK_BitCast:
    case CK_ArrayToPointerDecay:
    case CK_FunctionToPointerDecay:
    case CK_NullToMemberPointer:
    case CK_NullToPointer:
    case CK_IntegralToPointer:
    case CK_PointerToIntegral:
    case CK_PointerToBoolean:
    case CK_VectorSplat:
    case CK_IntegralCast:
    case CK_BooleanToSignedIntegral:
    case CK_IntegralToBoolean:
    case CK_IntegralToFloating:
    case CK_FloatingToIntegral:
    case CK_FloatingToBoolean:
    case CK_FloatingCast:
    case CK_FloatingRealToComplex:
    case CK_FloatingComplexToReal:
    case CK_FloatingComplexToBoolean:
    case CK_FloatingComplexCast:
    case CK_FloatingComplexToIntegralComplex:
    case CK_IntegralRealToComplex:
    case CK_IntegralComplexToReal:
    case CK_IntegralComplexToBoolean:
    case CK_IntegralComplexCast:
    case CK_IntegralComplexToFloatingComplex:
    case CK_DerivedToBaseMemberPointer:
    case CK_BaseToDerivedMemberPointer:
    case CK_MemberPointerToBoolean:
    case CK_ReinterpretMemberPointer:
    case CK_AnyPointerToBlockPointerCast:
    case CK_ARCProduceObject:
    case CK_ARCConsumeObject:
    case CK_ARCReclaimReturnedObject:
    case CK_ARCExtendBlockObject:
    case CK_CopyAndAutoreleaseBlockObject:
    case CK_IntToOCLSampler:
    case CK_FixedPointCast:
    case CK_FixedPointToBoolean:
      return EmitUnsupportedLValue(E, "unexpected cast lvalue");
  
    case CK_Dependent:
      llvm_unreachable("dependent cast kind in IR gen!");
  
    case CK_BuiltinFnToFnPtr:
      llvm_unreachable("builtin functions are handled elsewhere");
  
    // These are never l-values; just use the aggregate emission code.
    case CK_NonAtomicToAtomic:
    case CK_AtomicToNonAtomic:
      return EmitAggExprToLValue(E);
  
    case CK_Dynamic: {
      LValue LV = EmitLValue(E->getSubExpr());
      Address V = LV.getAddress();
      const auto *DCE = cast<CXXDynamicCastExpr>(E);
      return MakeNaturalAlignAddrLValue(EmitDynamicCast(V, DCE), E->getType());
    }
  
    case CK_ConstructorConversion:
    case CK_UserDefinedConversion:
    case CK_CPointerToObjCPointerCast:
    case CK_BlockPointerToObjCPointerCast:
    case CK_NoOp:
    case CK_LValueToRValue:
      return EmitLValue(E->getSubExpr());
  
    case CK_UncheckedDerivedToBase:
    case CK_DerivedToBase: {
      const RecordType *DerivedClassTy =
        E->getSubExpr()->getType()->getAs<RecordType>();
      auto *DerivedClassDecl = cast<CXXRecordDecl>(DerivedClassTy->getDecl());
  
      LValue LV = EmitLValue(E->getSubExpr());
      Address This = LV.getAddress();
  
      // Perform the derived-to-base conversion
      Address Base = GetAddressOfBaseClass(
          This, DerivedClassDecl, E->path_begin(), E->path_end(),
          /*NullCheckValue=*/false, E->getExprLoc());
  
      // TODO: Support accesses to members of base classes in TBAA. For now, we
      // conservatively pretend that the complete object is of the base class
      // type.
      return MakeAddrLValue(Base, E->getType(), LV.getBaseInfo(),
                            CGM.getTBAAInfoForSubobject(LV, E->getType()));
    }
    case CK_ToUnion:
      return EmitAggExprToLValue(E);
    case CK_BaseToDerived: {
      const RecordType *DerivedClassTy = E->getType()->getAs<RecordType>();
      auto *DerivedClassDecl = cast<CXXRecordDecl>(DerivedClassTy->getDecl());
  
      LValue LV = EmitLValue(E->getSubExpr());
  
      // Perform the base-to-derived conversion
      Address Derived =
        GetAddressOfDerivedClass(LV.getAddress(), DerivedClassDecl,
                                 E->path_begin(), E->path_end(),
                                 /*NullCheckValue=*/false);
  
      // C++11 [expr.static.cast]p2: Behavior is undefined if a downcast is
      // performed and the object is not of the derived type.
      if (sanitizePerformTypeCheck())
        EmitTypeCheck(TCK_DowncastReference, E->getExprLoc(),
                      Derived.getPointer(), E->getType());
  
      if (SanOpts.has(SanitizerKind::CFIDerivedCast))
        EmitVTablePtrCheckForCast(E->getType(), Derived.getPointer(),
                                  /*MayBeNull=*/false, CFITCK_DerivedCast,
                                  E->getBeginLoc());
  
      return MakeAddrLValue(Derived, E->getType(), LV.getBaseInfo(),
                            CGM.getTBAAInfoForSubobject(LV, E->getType()));
    }
    case CK_LValueBitCast: {
      // This must be a reinterpret_cast (or c-style equivalent).
      const auto *CE = cast<ExplicitCastExpr>(E);
  
      CGM.EmitExplicitCastExprType(CE, this);
      LValue LV = EmitLValue(E->getSubExpr());
      Address V = Builder.CreateBitCast(LV.getAddress(),
                                        ConvertType(CE->getTypeAsWritten()));
  
      if (SanOpts.has(SanitizerKind::CFIUnrelatedCast))
        EmitVTablePtrCheckForCast(E->getType(), V.getPointer(),
                                  /*MayBeNull=*/false, CFITCK_UnrelatedCast,
                                  E->getBeginLoc());
  
      return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
                            CGM.getTBAAInfoForSubobject(LV, E->getType()));
    }
    case CK_AddressSpaceConversion: {
      LValue LV = EmitLValue(E->getSubExpr());
      QualType DestTy = getContext().getPointerType(E->getType());
      llvm::Value *V = getTargetHooks().performAddrSpaceCast(
          *this, LV.getPointer(), E->getSubExpr()->getType().getAddressSpace(),
          E->getType().getAddressSpace(), ConvertType(DestTy));
      return MakeAddrLValue(Address(V, LV.getAddress().getAlignment()),
                            E->getType(), LV.getBaseInfo(), LV.getTBAAInfo());
    }
    case CK_ObjCObjectLValueCast: {
      LValue LV = EmitLValue(E->getSubExpr());
      Address V = Builder.CreateElementBitCast(LV.getAddress(),
                                               ConvertType(E->getType()));
      return MakeAddrLValue(V, E->getType(), LV.getBaseInfo(),
                            CGM.getTBAAInfoForSubobject(LV, E->getType()));
    }
    case CK_ZeroToOCLOpaqueType:
      llvm_unreachable("NULL to OpenCL opaque type lvalue cast is not valid");
    }
  
    llvm_unreachable("Unhandled lvalue cast kind?");
  }
  
  LValue CodeGenFunction::EmitOpaqueValueLValue(const OpaqueValueExpr *e) {
    assert(OpaqueValueMappingData::shouldBindAsLValue(e));
    return getOrCreateOpaqueLValueMapping(e);
  }
  
  LValue
  CodeGenFunction::getOrCreateOpaqueLValueMapping(const OpaqueValueExpr *e) {
    assert(OpaqueValueMapping::shouldBindAsLValue(e));
  
    llvm::DenseMap<const OpaqueValueExpr*,LValue>::iterator
        it = OpaqueLValues.find(e);
  
    if (it != OpaqueLValues.end())
      return it->second;
  
    assert(e->isUnique() && "LValue for a nonunique OVE hasn't been emitted");
    return EmitLValue(e->getSourceExpr());
  }
  
  RValue
  CodeGenFunction::getOrCreateOpaqueRValueMapping(const OpaqueValueExpr *e) {
    assert(!OpaqueValueMapping::shouldBindAsLValue(e));
  
    llvm::DenseMap<const OpaqueValueExpr*,RValue>::iterator
        it = OpaqueRValues.find(e);
  
    if (it != OpaqueRValues.end())
      return it->second;
  
    assert(e->isUnique() && "RValue for a nonunique OVE hasn't been emitted");
    return EmitAnyExpr(e->getSourceExpr());
  }
  
  RValue CodeGenFunction::EmitRValueForField(LValue LV,
                                             const FieldDecl *FD,
                                             SourceLocation Loc) {
    QualType FT = FD->getType();
    LValue FieldLV = EmitLValueForField(LV, FD);
    switch (getEvaluationKind(FT)) {
    case TEK_Complex:
      return RValue::getComplex(EmitLoadOfComplex(FieldLV, Loc));
    case TEK_Aggregate:
      return FieldLV.asAggregateRValue();
    case TEK_Scalar:
      // This routine is used to load fields one-by-one to perform a copy, so
      // don't load reference fields.
      if (FD->getType()->isReferenceType())
        return RValue::get(FieldLV.getPointer());
      return EmitLoadOfLValue(FieldLV, Loc);
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  //===--------------------------------------------------------------------===//
  //                             Expression Emission
  //===--------------------------------------------------------------------===//
  
  RValue CodeGenFunction::EmitCallExpr(const CallExpr *E,
                                       ReturnValueSlot ReturnValue) {
    // Builtins never have block type.
    if (E->getCallee()->getType()->isBlockPointerType())
      return EmitBlockCallExpr(E, ReturnValue);
  
    if (const auto *CE = dyn_cast<CXXMemberCallExpr>(E))
      return EmitCXXMemberCallExpr(CE, ReturnValue);
  
    if (const auto *CE = dyn_cast<CUDAKernelCallExpr>(E))
      return EmitCUDAKernelCallExpr(CE, ReturnValue);
  
    if (const auto *CE = dyn_cast<CXXOperatorCallExpr>(E))
      if (const CXXMethodDecl *MD =
            dyn_cast_or_null<CXXMethodDecl>(CE->getCalleeDecl()))
        return EmitCXXOperatorMemberCallExpr(CE, MD, ReturnValue);
  
    CGCallee callee = EmitCallee(E->getCallee());
  
    if (callee.isBuiltin()) {
      return EmitBuiltinExpr(callee.getBuiltinDecl(), callee.getBuiltinID(),
                             E, ReturnValue);
    }
  
    if (callee.isPseudoDestructor()) {
      return EmitCXXPseudoDestructorExpr(callee.getPseudoDestructorExpr());
    }
  
    return EmitCall(E->getCallee()->getType(), callee, E, ReturnValue);
  }
  
  /// Emit a CallExpr without considering whether it might be a subclass.
  RValue CodeGenFunction::EmitSimpleCallExpr(const CallExpr *E,
                                             ReturnValueSlot ReturnValue) {
    CGCallee Callee = EmitCallee(E->getCallee());
    return EmitCall(E->getCallee()->getType(), Callee, E, ReturnValue);
  }
  
  static CGCallee EmitDirectCallee(CodeGenFunction &CGF, const FunctionDecl *FD) {
    if (auto builtinID = FD->getBuiltinID()) {
      return CGCallee::forBuiltin(builtinID, FD);
    }
  
    llvm::Constant *calleePtr = EmitFunctionDeclPointer(CGF.CGM, FD);
    return CGCallee::forDirect(calleePtr, GlobalDecl(FD));
  }
  
  CGCallee CodeGenFunction::EmitCallee(const Expr *E) {
    E = E->IgnoreParens();
  
    // Look through function-to-pointer decay.
    if (auto ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getCastKind() == CK_FunctionToPointerDecay ||
          ICE->getCastKind() == CK_BuiltinFnToFnPtr) {
        return EmitCallee(ICE->getSubExpr());
      }
  
    // Resolve direct calls.
    } else if (auto DRE = dyn_cast<DeclRefExpr>(E)) {
      if (auto FD = dyn_cast<FunctionDecl>(DRE->getDecl())) {
        return EmitDirectCallee(*this, FD);
      }
    } else if (auto ME = dyn_cast<MemberExpr>(E)) {
      if (auto FD = dyn_cast<FunctionDecl>(ME->getMemberDecl())) {
        EmitIgnoredExpr(ME->getBase());
        return EmitDirectCallee(*this, FD);
      }
  
    // Look through template substitutions.
    } else if (auto NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E)) {
      return EmitCallee(NTTP->getReplacement());
  
    // Treat pseudo-destructor calls differently.
    } else if (auto PDE = dyn_cast<CXXPseudoDestructorExpr>(E)) {
      return CGCallee::forPseudoDestructor(PDE);
    }
  
    // Otherwise, we have an indirect reference.
    llvm::Value *calleePtr;
    QualType functionType;
    if (auto ptrType = E->getType()->getAs<PointerType>()) {
      calleePtr = EmitScalarExpr(E);
      functionType = ptrType->getPointeeType();
    } else {
      functionType = E->getType();
      calleePtr = EmitLValue(E).getPointer();
    }
    assert(functionType->isFunctionType());
  
    GlobalDecl GD;
    if (const auto *VD =
            dyn_cast_or_null<VarDecl>(E->getReferencedDeclOfCallee()))
      GD = GlobalDecl(VD);
  
    CGCalleeInfo calleeInfo(functionType->getAs<FunctionProtoType>(), GD);
    CGCallee callee(calleeInfo, calleePtr);
    return callee;
  }
  
  LValue CodeGenFunction::EmitBinaryOperatorLValue(const BinaryOperator *E) {
    // Comma expressions just emit their LHS then their RHS as an l-value.
    if (E->getOpcode() == BO_Comma) {
      EmitIgnoredExpr(E->getLHS());
      EnsureInsertPoint();
      return EmitLValue(E->getRHS());
    }
  
    if (E->getOpcode() == BO_PtrMemD ||
        E->getOpcode() == BO_PtrMemI)
      return EmitPointerToDataMemberBinaryExpr(E);
  
    assert(E->getOpcode() == BO_Assign && "unexpected binary l-value");
  
    // Note that in all of these cases, __block variables need the RHS
    // evaluated first just in case the variable gets moved by the RHS.
  
    switch (getEvaluationKind(E->getType())) {
    case TEK_Scalar: {
      switch (E->getLHS()->getType().getObjCLifetime()) {
      case Qualifiers::OCL_Strong:
        return EmitARCStoreStrong(E, /*ignored*/ false).first;
  
      case Qualifiers::OCL_Autoreleasing:
        return EmitARCStoreAutoreleasing(E).first;
  
      // No reason to do any of these differently.
      case Qualifiers::OCL_None:
      case Qualifiers::OCL_ExplicitNone:
      case Qualifiers::OCL_Weak:
        break;
      }
  
      RValue RV = EmitAnyExpr(E->getRHS());
      LValue LV = EmitCheckedLValue(E->getLHS(), TCK_Store);
      if (RV.isScalar())
        EmitNullabilityCheck(LV, RV.getScalarVal(), E->getExprLoc());
      EmitStoreThroughLValue(RV, LV);
      return LV;
    }
  
    case TEK_Complex:
      return EmitComplexAssignmentLValue(E);
  
    case TEK_Aggregate:
      return EmitAggExprToLValue(E);
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
    RValue RV = EmitCallExpr(E);
  
    if (!RV.isScalar())
      return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
                            AlignmentSource::Decl);
  
    assert(E->getCallReturnType(getContext())->isReferenceType() &&
           "Can't have a scalar return unless the return type is a "
           "reference type!");
  
    return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType());
  }
  
  LValue CodeGenFunction::EmitVAArgExprLValue(const VAArgExpr *E) {
    // FIXME: This shouldn't require another copy.
    return EmitAggExprToLValue(E);
  }
  
  LValue CodeGenFunction::EmitCXXConstructLValue(const CXXConstructExpr *E) {
    assert(E->getType()->getAsCXXRecordDecl()->hasTrivialDestructor()
           && "binding l-value to type which needs a temporary");
    AggValueSlot Slot = CreateAggTemp(E->getType());
    EmitCXXConstructExpr(E, Slot);
    return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl);
  }
  
  LValue
  CodeGenFunction::EmitCXXTypeidLValue(const CXXTypeidExpr *E) {
    return MakeNaturalAlignAddrLValue(EmitCXXTypeidExpr(E), E->getType());
  }
  
  Address CodeGenFunction::EmitCXXUuidofExpr(const CXXUuidofExpr *E) {
    return Builder.CreateElementBitCast(CGM.GetAddrOfUuidDescriptor(E),
                                        ConvertType(E->getType()));
  }
  
  LValue CodeGenFunction::EmitCXXUuidofLValue(const CXXUuidofExpr *E) {
    return MakeAddrLValue(EmitCXXUuidofExpr(E), E->getType(),
                          AlignmentSource::Decl);
  }
  
  LValue
  CodeGenFunction::EmitCXXBindTemporaryLValue(const CXXBindTemporaryExpr *E) {
    AggValueSlot Slot = CreateAggTemp(E->getType(), "temp.lvalue");
    Slot.setExternallyDestructed();
    EmitAggExpr(E->getSubExpr(), Slot);
    EmitCXXTemporary(E->getTemporary(), E->getType(), Slot.getAddress());
    return MakeAddrLValue(Slot.getAddress(), E->getType(), AlignmentSource::Decl);
  }
  
  LValue CodeGenFunction::EmitObjCMessageExprLValue(const ObjCMessageExpr *E) {
    RValue RV = EmitObjCMessageExpr(E);
  
    if (!RV.isScalar())
      return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
                            AlignmentSource::Decl);
  
    assert(E->getMethodDecl()->getReturnType()->isReferenceType() &&
           "Can't have a scalar return unless the return type is a "
           "reference type!");
  
    return MakeNaturalAlignPointeeAddrLValue(RV.getScalarVal(), E->getType());
  }
  
  LValue CodeGenFunction::EmitObjCSelectorLValue(const ObjCSelectorExpr *E) {
    Address V =
      CGM.getObjCRuntime().GetAddrOfSelector(*this, E->getSelector());
    return MakeAddrLValue(V, E->getType(), AlignmentSource::Decl);
  }
  
  llvm::Value *CodeGenFunction::EmitIvarOffset(const ObjCInterfaceDecl *Interface,
                                               const ObjCIvarDecl *Ivar) {
    return CGM.getObjCRuntime().EmitIvarOffset(*this, Interface, Ivar);
  }
  
  LValue CodeGenFunction::EmitLValueForIvar(QualType ObjectTy,
                                            llvm::Value *BaseValue,
                                            const ObjCIvarDecl *Ivar,
                                            unsigned CVRQualifiers) {
    return CGM.getObjCRuntime().EmitObjCValueForIvar(*this, ObjectTy, BaseValue,
                                                     Ivar, CVRQualifiers);
  }
  
  LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
    // FIXME: A lot of the code below could be shared with EmitMemberExpr.
    llvm::Value *BaseValue = nullptr;
    const Expr *BaseExpr = E->getBase();
    Qualifiers BaseQuals;
    QualType ObjectTy;
    if (E->isArrow()) {
      BaseValue = EmitScalarExpr(BaseExpr);
      ObjectTy = BaseExpr->getType()->getPointeeType();
      BaseQuals = ObjectTy.getQualifiers();
    } else {
      LValue BaseLV = EmitLValue(BaseExpr);
      BaseValue = BaseLV.getPointer();
      ObjectTy = BaseExpr->getType();
      BaseQuals = ObjectTy.getQualifiers();
    }
  
    LValue LV =
      EmitLValueForIvar(ObjectTy, BaseValue, E->getDecl(),
                        BaseQuals.getCVRQualifiers());
    setObjCGCLValueClass(getContext(), E, LV);
    return LV;
  }
  
  LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
    // Can only get l-value for message expression returning aggregate type
    RValue RV = EmitAnyExprToTemp(E);
    return MakeAddrLValue(RV.getAggregateAddress(), E->getType(),
                          AlignmentSource::Decl);
  }
  
  RValue CodeGenFunction::EmitCall(QualType CalleeType, const CGCallee &OrigCallee,
                                   const CallExpr *E, ReturnValueSlot ReturnValue,
                                   llvm::Value *Chain) {
    // Get the actual function type. The callee type will always be a pointer to
    // function type or a block pointer type.
    assert(CalleeType->isFunctionPointerType() &&
           "Call must have function pointer type!");
  
    const Decl *TargetDecl =
        OrigCallee.getAbstractInfo().getCalleeDecl().getDecl();
  
    if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
      // We can only guarantee that a function is called from the correct
      // context/function based on the appropriate target attributes,
      // so only check in the case where we have both always_inline and target
      // since otherwise we could be making a conditional call after a check for
      // the proper cpu features (and it won't cause code generation issues due to
      // function based code generation).
      if (TargetDecl->hasAttr<AlwaysInlineAttr>() &&
          TargetDecl->hasAttr<TargetAttr>())
        checkTargetFeatures(E, FD);
  
    CalleeType = getContext().getCanonicalType(CalleeType);
  
    auto PointeeType = cast<PointerType>(CalleeType)->getPointeeType();
  
    CGCallee Callee = OrigCallee;
  
    if (getLangOpts().CPlusPlus && SanOpts.has(SanitizerKind::Function) &&
        (!TargetDecl || !isa<FunctionDecl>(TargetDecl))) {
      if (llvm::Constant *PrefixSig =
              CGM.getTargetCodeGenInfo().getUBSanFunctionSignature(CGM)) {
        SanitizerScope SanScope(this);
        // Remove any (C++17) exception specifications, to allow calling e.g. a
        // noexcept function through a non-noexcept pointer.
        auto ProtoTy =
          getContext().getFunctionTypeWithExceptionSpec(PointeeType, EST_None);
        llvm::Constant *FTRTTIConst =
            CGM.GetAddrOfRTTIDescriptor(ProtoTy, /*ForEH=*/true);
        llvm::Type *PrefixStructTyElems[] = {PrefixSig->getType(), Int32Ty};
        llvm::StructType *PrefixStructTy = llvm::StructType::get(
            CGM.getLLVMContext(), PrefixStructTyElems, /*isPacked=*/true);
  
        llvm::Value *CalleePtr = Callee.getFunctionPointer();
  
        llvm::Value *CalleePrefixStruct = Builder.CreateBitCast(
            CalleePtr, llvm::PointerType::getUnqual(PrefixStructTy));
        llvm::Value *CalleeSigPtr =
            Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 0);
        llvm::Value *CalleeSig =
            Builder.CreateAlignedLoad(CalleeSigPtr, getIntAlign());
        llvm::Value *CalleeSigMatch = Builder.CreateICmpEQ(CalleeSig, PrefixSig);
  
        llvm::BasicBlock *Cont = createBasicBlock("cont");
        llvm::BasicBlock *TypeCheck = createBasicBlock("typecheck");
        Builder.CreateCondBr(CalleeSigMatch, TypeCheck, Cont);
  
        EmitBlock(TypeCheck);
        llvm::Value *CalleeRTTIPtr =
            Builder.CreateConstGEP2_32(PrefixStructTy, CalleePrefixStruct, 0, 1);
        llvm::Value *CalleeRTTIEncoded =
            Builder.CreateAlignedLoad(CalleeRTTIPtr, getPointerAlign());
        llvm::Value *CalleeRTTI =
            DecodeAddrUsedInPrologue(CalleePtr, CalleeRTTIEncoded);
        llvm::Value *CalleeRTTIMatch =
            Builder.CreateICmpEQ(CalleeRTTI, FTRTTIConst);
        llvm::Constant *StaticData[] = {EmitCheckSourceLocation(E->getBeginLoc()),
                                        EmitCheckTypeDescriptor(CalleeType)};
        EmitCheck(std::make_pair(CalleeRTTIMatch, SanitizerKind::Function),
                  SanitizerHandler::FunctionTypeMismatch, StaticData, CalleePtr);
  
        Builder.CreateBr(Cont);
        EmitBlock(Cont);
      }
    }
  
    const auto *FnType = cast<FunctionType>(PointeeType);
  
    // If we are checking indirect calls and this call is indirect, check that the
    // function pointer is a member of the bit set for the function type.
    if (SanOpts.has(SanitizerKind::CFIICall) &&
        (!TargetDecl || !isa<FunctionDecl>(TargetDecl))) {
      SanitizerScope SanScope(this);
      EmitSanitizerStatReport(llvm::SanStat_CFI_ICall);
  
      llvm::Metadata *MD;
      if (CGM.getCodeGenOpts().SanitizeCfiICallGeneralizePointers)
        MD = CGM.CreateMetadataIdentifierGeneralized(QualType(FnType, 0));
      else
        MD = CGM.CreateMetadataIdentifierForType(QualType(FnType, 0));
  
      llvm::Value *TypeId = llvm::MetadataAsValue::get(getLLVMContext(), MD);
  
      llvm::Value *CalleePtr = Callee.getFunctionPointer();
      llvm::Value *CastedCallee = Builder.CreateBitCast(CalleePtr, Int8PtrTy);
      llvm::Value *TypeTest = Builder.CreateCall(
          CGM.getIntrinsic(llvm::Intrinsic::type_test), {CastedCallee, TypeId});
  
      auto CrossDsoTypeId = CGM.CreateCrossDsoCfiTypeId(MD);
      llvm::Constant *StaticData[] = {
          llvm::ConstantInt::get(Int8Ty, CFITCK_ICall),
          EmitCheckSourceLocation(E->getBeginLoc()),
          EmitCheckTypeDescriptor(QualType(FnType, 0)),
      };
      if (CGM.getCodeGenOpts().SanitizeCfiCrossDso && CrossDsoTypeId) {
        EmitCfiSlowPathCheck(SanitizerKind::CFIICall, TypeTest, CrossDsoTypeId,
                             CastedCallee, StaticData);
      } else {
        EmitCheck(std::make_pair(TypeTest, SanitizerKind::CFIICall),
                  SanitizerHandler::CFICheckFail, StaticData,
                  {CastedCallee, llvm::UndefValue::get(IntPtrTy)});
      }
    }
  
    CallArgList Args;
    if (Chain)
      Args.add(RValue::get(Builder.CreateBitCast(Chain, CGM.VoidPtrTy)),
               CGM.getContext().VoidPtrTy);
  
    // C++17 requires that we evaluate arguments to a call using assignment syntax
    // right-to-left, and that we evaluate arguments to certain other operators
    // left-to-right. Note that we allow this to override the order dictated by
    // the calling convention on the MS ABI, which means that parameter
    // destruction order is not necessarily reverse construction order.
    // FIXME: Revisit this based on C++ committee response to unimplementability.
    EvaluationOrder Order = EvaluationOrder::Default;
    if (auto *OCE = dyn_cast<CXXOperatorCallExpr>(E)) {
      if (OCE->isAssignmentOp())
        Order = EvaluationOrder::ForceRightToLeft;
      else {
        switch (OCE->getOperator()) {
        case OO_LessLess:
        case OO_GreaterGreater:
        case OO_AmpAmp:
        case OO_PipePipe:
        case OO_Comma:
        case OO_ArrowStar:
          Order = EvaluationOrder::ForceLeftToRight;
          break;
        default:
          break;
        }
      }
    }
  
    EmitCallArgs(Args, dyn_cast<FunctionProtoType>(FnType), E->arguments(),
                 E->getDirectCallee(), /*ParamsToSkip*/ 0, Order);
  
    const CGFunctionInfo &FnInfo = CGM.getTypes().arrangeFreeFunctionCall(
        Args, FnType, /*isChainCall=*/Chain);
  
    // C99 6.5.2.2p6:
    //   If the expression that denotes the called function has a type
    //   that does not include a prototype, [the default argument
    //   promotions are performed]. If the number of arguments does not
    //   equal the number of parameters, the behavior is undefined. If
    //   the function is defined with a type that includes a prototype,
    //   and either the prototype ends with an ellipsis (, ...) or the
    //   types of the arguments after promotion are not compatible with
    //   the types of the parameters, the behavior is undefined. If the
    //   function is defined with a type that does not include a
    //   prototype, and the types of the arguments after promotion are
    //   not compatible with those of the parameters after promotion,
    //   the behavior is undefined [except in some trivial cases].
    // That is, in the general case, we should assume that a call
    // through an unprototyped function type works like a *non-variadic*
    // call.  The way we make this work is to cast to the exact type
    // of the promoted arguments.
    //
    // Chain calls use this same code path to add the invisible chain parameter
    // to the function type.
    if (isa<FunctionNoProtoType>(FnType) || Chain) {
      llvm::Type *CalleeTy = getTypes().GetFunctionType(FnInfo);
      CalleeTy = CalleeTy->getPointerTo();
  
      llvm::Value *CalleePtr = Callee.getFunctionPointer();
      CalleePtr = Builder.CreateBitCast(CalleePtr, CalleeTy, "callee.knr.cast");
      Callee.setFunctionPointer(CalleePtr);
    }
  
    return EmitCall(FnInfo, Callee, ReturnValue, Args, nullptr, E->getExprLoc());
  }
  
  LValue CodeGenFunction::
  EmitPointerToDataMemberBinaryExpr(const BinaryOperator *E) {
    Address BaseAddr = Address::invalid();
    if (E->getOpcode() == BO_PtrMemI) {
      BaseAddr = EmitPointerWithAlignment(E->getLHS());
    } else {
      BaseAddr = EmitLValue(E->getLHS()).getAddress();
    }
  
    llvm::Value *OffsetV = EmitScalarExpr(E->getRHS());
  
    const MemberPointerType *MPT
      = E->getRHS()->getType()->getAs<MemberPointerType>();
  
    LValueBaseInfo BaseInfo;
    TBAAAccessInfo TBAAInfo;
    Address MemberAddr =
      EmitCXXMemberDataPointerAddress(E, BaseAddr, OffsetV, MPT, &BaseInfo,
                                      &TBAAInfo);
  
    return MakeAddrLValue(MemberAddr, MPT->getPointeeType(), BaseInfo, TBAAInfo);
  }
  
  /// Given the address of a temporary variable, produce an r-value of
  /// its type.
  RValue CodeGenFunction::convertTempToRValue(Address addr,
                                              QualType type,
                                              SourceLocation loc) {
    LValue lvalue = MakeAddrLValue(addr, type, AlignmentSource::Decl);
    switch (getEvaluationKind(type)) {
    case TEK_Complex:
      return RValue::getComplex(EmitLoadOfComplex(lvalue, loc));
    case TEK_Aggregate:
      return lvalue.asAggregateRValue();
    case TEK_Scalar:
      return RValue::get(EmitLoadOfScalar(lvalue, loc));
    }
    llvm_unreachable("bad evaluation kind");
  }
  
  void CodeGenFunction::SetFPAccuracy(llvm::Value *Val, float Accuracy) {
    assert(Val->getType()->isFPOrFPVectorTy());
    if (Accuracy == 0.0 || !isa<llvm::Instruction>(Val))
      return;
  
    llvm::MDBuilder MDHelper(getLLVMContext());
    llvm::MDNode *Node = MDHelper.createFPMath(Accuracy);
  
    cast<llvm::Instruction>(Val)->setMetadata(llvm::LLVMContext::MD_fpmath, Node);
  }
  
  namespace {
    struct LValueOrRValue {
      LValue LV;
      RValue RV;
    };
  }
  
  static LValueOrRValue emitPseudoObjectExpr(CodeGenFunction &CGF,
                                             const PseudoObjectExpr *E,
                                             bool forLValue,
                                             AggValueSlot slot) {
    SmallVector<CodeGenFunction::OpaqueValueMappingData, 4> opaques;
  
    // Find the result expression, if any.
    const Expr *resultExpr = E->getResultExpr();
    LValueOrRValue result;
  
    for (PseudoObjectExpr::const_semantics_iterator
           i = E->semantics_begin(), e = E->semantics_end(); i != e; ++i) {
      const Expr *semantic = *i;
  
      // If this semantic expression is an opaque value, bind it
      // to the result of its source expression.
      if (const auto *ov = dyn_cast<OpaqueValueExpr>(semantic)) {
        // Skip unique OVEs.
        if (ov->isUnique()) {
          assert(ov != resultExpr &&
                 "A unique OVE cannot be used as the result expression");
          continue;
        }
  
        // If this is the result expression, we may need to evaluate
        // directly into the slot.
        typedef CodeGenFunction::OpaqueValueMappingData OVMA;
        OVMA opaqueData;
        if (ov == resultExpr && ov->isRValue() && !forLValue &&
            CodeGenFunction::hasAggregateEvaluationKind(ov->getType())) {
          CGF.EmitAggExpr(ov->getSourceExpr(), slot);
          LValue LV = CGF.MakeAddrLValue(slot.getAddress(), ov->getType(),
                                         AlignmentSource::Decl);
          opaqueData = OVMA::bind(CGF, ov, LV);
          result.RV = slot.asRValue();
  
        // Otherwise, emit as normal.
        } else {
          opaqueData = OVMA::bind(CGF, ov, ov->getSourceExpr());
  
          // If this is the result, also evaluate the result now.
          if (ov == resultExpr) {
            if (forLValue)
              result.LV = CGF.EmitLValue(ov);
            else
              result.RV = CGF.EmitAnyExpr(ov, slot);
          }
        }
  
        opaques.push_back(opaqueData);
  
      // Otherwise, if the expression is the result, evaluate it
      // and remember the result.
      } else if (semantic == resultExpr) {
        if (forLValue)
          result.LV = CGF.EmitLValue(semantic);
        else
          result.RV = CGF.EmitAnyExpr(semantic, slot);
  
      // Otherwise, evaluate the expression in an ignored context.
      } else {
        CGF.EmitIgnoredExpr(semantic);
      }
    }
  
    // Unbind all the opaques now.
    for (unsigned i = 0, e = opaques.size(); i != e; ++i)
      opaques[i].unbind(CGF);
  
    return result;
  }
  
  RValue CodeGenFunction::EmitPseudoObjectRValue(const PseudoObjectExpr *E,
                                                 AggValueSlot slot) {
    return emitPseudoObjectExpr(*this, E, false, slot).RV;
  }
  
  LValue CodeGenFunction::EmitPseudoObjectLValue(const PseudoObjectExpr *E) {
    return emitPseudoObjectExpr(*this, E, true, AggValueSlot::ignored()).LV;
  }
  