text: //===--- Expr.cpp - Expression AST Node Implementation --------------------===//
  //
  // 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 file implements the Expr class and subclasses.
  //
  //===----------------------------------------------------------------------===//
  
  #include "clang/AST/Expr.h"
  #include "clang/AST/APValue.h"
  #include "clang/AST/ASTContext.h"
  #include "clang/AST/Attr.h"
  #include "clang/AST/DeclCXX.h"
  #include "clang/AST/DeclObjC.h"
  #include "clang/AST/DeclTemplate.h"
  #include "clang/AST/EvaluatedExprVisitor.h"
  #include "clang/AST/ExprCXX.h"
  #include "clang/AST/Mangle.h"
  #include "clang/AST/RecordLayout.h"
  #include "clang/AST/StmtVisitor.h"
  #include "clang/Basic/Builtins.h"
  #include "clang/Basic/CharInfo.h"
  #include "clang/Basic/SourceManager.h"
  #include "clang/Basic/TargetInfo.h"
  #include "clang/Lex/Lexer.h"
  #include "clang/Lex/LiteralSupport.h"
  #include "llvm/Support/ErrorHandling.h"
  #include "llvm/Support/raw_ostream.h"
  #include <algorithm>
  #include <cstring>
  using namespace clang;
  
  const Expr *Expr::getBestDynamicClassTypeExpr() const {
    const Expr *E = this;
    while (true) {
      E = E->ignoreParenBaseCasts();
  
      // Follow the RHS of a comma operator.
      if (auto *BO = dyn_cast<BinaryOperator>(E)) {
        if (BO->getOpcode() == BO_Comma) {
          E = BO->getRHS();
          continue;
        }
      }
  
      // Step into initializer for materialized temporaries.
      if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E)) {
        E = MTE->GetTemporaryExpr();
        continue;
      }
  
      break;
    }
  
    return E;
  }
  
  const CXXRecordDecl *Expr::getBestDynamicClassType() const {
    const Expr *E = getBestDynamicClassTypeExpr();
    QualType DerivedType = E->getType();
    if (const PointerType *PTy = DerivedType->getAs<PointerType>())
      DerivedType = PTy->getPointeeType();
  
    if (DerivedType->isDependentType())
      return nullptr;
  
    const RecordType *Ty = DerivedType->castAs<RecordType>();
    Decl *D = Ty->getDecl();
    return cast<CXXRecordDecl>(D);
  }
  
  const Expr *Expr::skipRValueSubobjectAdjustments(
      SmallVectorImpl<const Expr *> &CommaLHSs,
      SmallVectorImpl<SubobjectAdjustment> &Adjustments) const {
    const Expr *E = this;
    while (true) {
      E = E->IgnoreParens();
  
      if (const CastExpr *CE = dyn_cast<CastExpr>(E)) {
        if ((CE->getCastKind() == CK_DerivedToBase ||
             CE->getCastKind() == CK_UncheckedDerivedToBase) &&
            E->getType()->isRecordType()) {
          E = CE->getSubExpr();
          CXXRecordDecl *Derived
            = cast<CXXRecordDecl>(E->getType()->getAs<RecordType>()->getDecl());
          Adjustments.push_back(SubobjectAdjustment(CE, Derived));
          continue;
        }
  
        if (CE->getCastKind() == CK_NoOp) {
          E = CE->getSubExpr();
          continue;
        }
      } else if (const MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
        if (!ME->isArrow()) {
          assert(ME->getBase()->getType()->isRecordType());
          if (FieldDecl *Field = dyn_cast<FieldDecl>(ME->getMemberDecl())) {
            if (!Field->isBitField() && !Field->getType()->isReferenceType()) {
              E = ME->getBase();
              Adjustments.push_back(SubobjectAdjustment(Field));
              continue;
            }
          }
        }
      } else if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
        if (BO->getOpcode() == BO_PtrMemD) {
          assert(BO->getRHS()->isRValue());
          E = BO->getLHS();
          const MemberPointerType *MPT =
            BO->getRHS()->getType()->getAs<MemberPointerType>();
          Adjustments.push_back(SubobjectAdjustment(MPT, BO->getRHS()));
          continue;
        } else if (BO->getOpcode() == BO_Comma) {
          CommaLHSs.push_back(BO->getLHS());
          E = BO->getRHS();
          continue;
        }
      }
  
      // Nothing changed.
      break;
    }
    return E;
  }
  
  /// isKnownToHaveBooleanValue - Return true if this is an integer expression
  /// that is known to return 0 or 1.  This happens for _Bool/bool expressions
  /// but also int expressions which are produced by things like comparisons in
  /// C.
  bool Expr::isKnownToHaveBooleanValue() const {
    const Expr *E = IgnoreParens();
  
    // If this value has _Bool type, it is obvious 0/1.
    if (E->getType()->isBooleanType()) return true;
    // If this is a non-scalar-integer type, we don't care enough to try.
    if (!E->getType()->isIntegralOrEnumerationType()) return false;
  
    if (const UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) {
      switch (UO->getOpcode()) {
      case UO_Plus:
        return UO->getSubExpr()->isKnownToHaveBooleanValue();
      case UO_LNot:
        return true;
      default:
        return false;
      }
    }
  
    // Only look through implicit casts.  If the user writes
    // '(int) (a && b)' treat it as an arbitrary int.
    if (const ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E))
      return CE->getSubExpr()->isKnownToHaveBooleanValue();
  
    if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
      switch (BO->getOpcode()) {
      default: return false;
      case BO_LT:   // Relational operators.
      case BO_GT:
      case BO_LE:
      case BO_GE:
      case BO_EQ:   // Equality operators.
      case BO_NE:
      case BO_LAnd: // AND operator.
      case BO_LOr:  // Logical OR operator.
        return true;
  
      case BO_And:  // Bitwise AND operator.
      case BO_Xor:  // Bitwise XOR operator.
      case BO_Or:   // Bitwise OR operator.
        // Handle things like (x==2)|(y==12).
        return BO->getLHS()->isKnownToHaveBooleanValue() &&
               BO->getRHS()->isKnownToHaveBooleanValue();
  
      case BO_Comma:
      case BO_Assign:
        return BO->getRHS()->isKnownToHaveBooleanValue();
      }
    }
  
    if (const ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E))
      return CO->getTrueExpr()->isKnownToHaveBooleanValue() &&
             CO->getFalseExpr()->isKnownToHaveBooleanValue();
  
    return false;
  }
  
  // Amusing macro metaprogramming hack: check whether a class provides
  // a more specific implementation of getExprLoc().
  //
  // See also Stmt.cpp:{getBeginLoc(),getEndLoc()}.
  namespace {
    /// This implementation is used when a class provides a custom
    /// implementation of getExprLoc.
    template <class E, class T>
    SourceLocation getExprLocImpl(const Expr *expr,
                                  SourceLocation (T::*v)() const) {
      return static_cast<const E*>(expr)->getExprLoc();
    }
  
    /// This implementation is used when a class doesn't provide
    /// a custom implementation of getExprLoc.  Overload resolution
    /// should pick it over the implementation above because it's
    /// more specialized according to function template partial ordering.
    template <class E>
    SourceLocation getExprLocImpl(const Expr *expr,
                                  SourceLocation (Expr::*v)() const) {
      return static_cast<const E *>(expr)->getBeginLoc();
    }
  }
  
  SourceLocation Expr::getExprLoc() const {
    switch (getStmtClass()) {
    case Stmt::NoStmtClass: llvm_unreachable("statement without class");
  #define ABSTRACT_STMT(type)
  #define STMT(type, base) \
    case Stmt::type##Class: break;
  #define EXPR(type, base) \
    case Stmt::type##Class: return getExprLocImpl<type>(this, &type::getExprLoc);
  #include "clang/AST/StmtNodes.inc"
    }
    llvm_unreachable("unknown expression kind");
  }
  
  //===----------------------------------------------------------------------===//
  // Primary Expressions.
  //===----------------------------------------------------------------------===//
  
  static void AssertResultStorageKind(ConstantExpr::ResultStorageKind Kind) {
    assert((Kind == ConstantExpr::RSK_APValue ||
            Kind == ConstantExpr::RSK_Int64 || Kind == ConstantExpr::RSK_None) &&
           "Invalid StorageKind Value");
  }
  
  ConstantExpr::ResultStorageKind
  ConstantExpr::getStorageKind(const APValue &Value) {
    switch (Value.getKind()) {
    case APValue::None:
    case APValue::Indeterminate:
      return ConstantExpr::RSK_None;
    case APValue::Int:
      if (!Value.getInt().needsCleanup())
        return ConstantExpr::RSK_Int64;
      LLVM_FALLTHROUGH;
    default:
      return ConstantExpr::RSK_APValue;
    }
  }
  
  ConstantExpr::ResultStorageKind
  ConstantExpr::getStorageKind(const Type *T, const ASTContext &Context) {
    if (T->isIntegralOrEnumerationType() && Context.getTypeInfo(T).Width <= 64)
      return ConstantExpr::RSK_Int64;
    return ConstantExpr::RSK_APValue;
  }
  
  void ConstantExpr::DefaultInit(ResultStorageKind StorageKind) {
    ConstantExprBits.ResultKind = StorageKind;
    ConstantExprBits.APValueKind = APValue::None;
    ConstantExprBits.HasCleanup = false;
    if (StorageKind == ConstantExpr::RSK_APValue)
      ::new (getTrailingObjects<APValue>()) APValue();
  }
  
  ConstantExpr::ConstantExpr(Expr *subexpr, ResultStorageKind StorageKind)
      : FullExpr(ConstantExprClass, subexpr) {
    DefaultInit(StorageKind);
  }
  
  ConstantExpr *ConstantExpr::Create(const ASTContext &Context, Expr *E,
                                     ResultStorageKind StorageKind) {
    assert(!isa<ConstantExpr>(E));
    AssertResultStorageKind(StorageKind);
    unsigned Size = totalSizeToAlloc<APValue, uint64_t>(
        StorageKind == ConstantExpr::RSK_APValue,
        StorageKind == ConstantExpr::RSK_Int64);
    void *Mem = Context.Allocate(Size, alignof(ConstantExpr));
    ConstantExpr *Self = new (Mem) ConstantExpr(E, StorageKind);
    return Self;
  }
  
  ConstantExpr *ConstantExpr::Create(const ASTContext &Context, Expr *E,
                                     const APValue &Result) {
    ResultStorageKind StorageKind = getStorageKind(Result);
    ConstantExpr *Self = Create(Context, E, StorageKind);
    Self->SetResult(Result, Context);
    return Self;
  }
  
  ConstantExpr::ConstantExpr(ResultStorageKind StorageKind, EmptyShell Empty)
      : FullExpr(ConstantExprClass, Empty) {
    DefaultInit(StorageKind);
  }
  
  ConstantExpr *ConstantExpr::CreateEmpty(const ASTContext &Context,
                                          ResultStorageKind StorageKind,
                                          EmptyShell Empty) {
    AssertResultStorageKind(StorageKind);
    unsigned Size = totalSizeToAlloc<APValue, uint64_t>(
        StorageKind == ConstantExpr::RSK_APValue,
        StorageKind == ConstantExpr::RSK_Int64);
    void *Mem = Context.Allocate(Size, alignof(ConstantExpr));
    ConstantExpr *Self = new (Mem) ConstantExpr(StorageKind, Empty);
    return Self;
  }
  
  void ConstantExpr::MoveIntoResult(APValue &Value, const ASTContext &Context) {
    assert(getStorageKind(Value) == ConstantExprBits.ResultKind &&
           "Invalid storage for this value kind");
    ConstantExprBits.APValueKind = Value.getKind();
    switch (ConstantExprBits.ResultKind) {
    case RSK_None:
      return;
    case RSK_Int64:
      Int64Result() = *Value.getInt().getRawData();
      ConstantExprBits.BitWidth = Value.getInt().getBitWidth();
      ConstantExprBits.IsUnsigned = Value.getInt().isUnsigned();
      return;
    case RSK_APValue:
      if (!ConstantExprBits.HasCleanup && Value.needsCleanup()) {
        ConstantExprBits.HasCleanup = true;
        Context.addDestruction(&APValueResult());
      }
      APValueResult() = std::move(Value);
      return;
    }
    llvm_unreachable("Invalid ResultKind Bits");
  }
  
  llvm::APSInt ConstantExpr::getResultAsAPSInt() const {
    switch (ConstantExprBits.ResultKind) {
    case ConstantExpr::RSK_APValue:
      return APValueResult().getInt();
    case ConstantExpr::RSK_Int64:
      return llvm::APSInt(llvm::APInt(ConstantExprBits.BitWidth, Int64Result()),
                          ConstantExprBits.IsUnsigned);
    default:
      llvm_unreachable("invalid Accessor");
    }
  }
  
  APValue ConstantExpr::getAPValueResult() const {
    switch (ConstantExprBits.ResultKind) {
    case ConstantExpr::RSK_APValue:
      return APValueResult();
    case ConstantExpr::RSK_Int64:
      return APValue(
          llvm::APSInt(llvm::APInt(ConstantExprBits.BitWidth, Int64Result()),
                       ConstantExprBits.IsUnsigned));
    case ConstantExpr::RSK_None:
      return APValue();
    }
    llvm_unreachable("invalid ResultKind");
  }
  
  /// Compute the type-, value-, and instantiation-dependence of a
  /// declaration reference
  /// based on the declaration being referenced.
  static void computeDeclRefDependence(const ASTContext &Ctx, NamedDecl *D,
                                       QualType T, bool &TypeDependent,
                                       bool &ValueDependent,
                                       bool &InstantiationDependent) {
    TypeDependent = false;
    ValueDependent = false;
    InstantiationDependent = false;
  
    // (TD) C++ [temp.dep.expr]p3:
    //   An id-expression is type-dependent if it contains:
    //
    // and
    //
    // (VD) C++ [temp.dep.constexpr]p2:
    //  An identifier is value-dependent if it is:
  
    //  (TD)  - an identifier that was declared with dependent type
    //  (VD)  - a name declared with a dependent type,
    if (T->isDependentType()) {
      TypeDependent = true;
      ValueDependent = true;
      InstantiationDependent = true;
      return;
    } else if (T->isInstantiationDependentType()) {
      InstantiationDependent = true;
    }
  
    //  (TD)  - a conversion-function-id that specifies a dependent type
    if (D->getDeclName().getNameKind()
                                  == DeclarationName::CXXConversionFunctionName) {
      QualType T = D->getDeclName().getCXXNameType();
      if (T->isDependentType()) {
        TypeDependent = true;
        ValueDependent = true;
        InstantiationDependent = true;
        return;
      }
  
      if (T->isInstantiationDependentType())
        InstantiationDependent = true;
    }
  
    //  (VD)  - the name of a non-type template parameter,
    if (isa<NonTypeTemplateParmDecl>(D)) {
      ValueDependent = true;
      InstantiationDependent = true;
      return;
    }
  
    //  (VD) - a constant with integral or enumeration type and is
    //         initialized with an expression that is value-dependent.
    //  (VD) - a constant with literal type and is initialized with an
    //         expression that is value-dependent [C++11].
    //  (VD) - FIXME: Missing from the standard:
    //       -  an entity with reference type and is initialized with an
    //          expression that is value-dependent [C++11]
    if (VarDecl *Var = dyn_cast<VarDecl>(D)) {
      if ((Ctx.getLangOpts().CPlusPlus11 ?
             Var->getType()->isLiteralType(Ctx) :
             Var->getType()->isIntegralOrEnumerationType()) &&
          (Var->getType().isConstQualified() ||
           Var->getType()->isReferenceType())) {
        if (const Expr *Init = Var->getAnyInitializer())
          if (Init->isValueDependent()) {
            ValueDependent = true;
            InstantiationDependent = true;
          }
      }
  
      // (VD) - FIXME: Missing from the standard:
      //      -  a member function or a static data member of the current
      //         instantiation
      if (Var->isStaticDataMember() &&
          Var->getDeclContext()->isDependentContext()) {
        ValueDependent = true;
        InstantiationDependent = true;
        TypeSourceInfo *TInfo = Var->getFirstDecl()->getTypeSourceInfo();
        if (TInfo->getType()->isIncompleteArrayType())
          TypeDependent = true;
      }
  
      return;
    }
  
    // (VD) - FIXME: Missing from the standard:
    //      -  a member function or a static data member of the current
    //         instantiation
    if (isa<CXXMethodDecl>(D) && D->getDeclContext()->isDependentContext()) {
      ValueDependent = true;
      InstantiationDependent = true;
    }
  }
  
  void DeclRefExpr::computeDependence(const ASTContext &Ctx) {
    bool TypeDependent = false;
    bool ValueDependent = false;
    bool InstantiationDependent = false;
    computeDeclRefDependence(Ctx, getDecl(), getType(), TypeDependent,
                             ValueDependent, InstantiationDependent);
  
    ExprBits.TypeDependent |= TypeDependent;
    ExprBits.ValueDependent |= ValueDependent;
    ExprBits.InstantiationDependent |= InstantiationDependent;
  
    // Is the declaration a parameter pack?
    if (getDecl()->isParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;
  }
  
  DeclRefExpr::DeclRefExpr(const ASTContext &Ctx, ValueDecl *D,
                           bool RefersToEnclosingVariableOrCapture, QualType T,
                           ExprValueKind VK, SourceLocation L,
                           const DeclarationNameLoc &LocInfo,
                           NonOdrUseReason NOUR)
      : Expr(DeclRefExprClass, T, VK, OK_Ordinary, false, false, false, false),
        D(D), DNLoc(LocInfo) {
    DeclRefExprBits.HasQualifier = false;
    DeclRefExprBits.HasTemplateKWAndArgsInfo = false;
    DeclRefExprBits.HasFoundDecl = false;
    DeclRefExprBits.HadMultipleCandidates = false;
    DeclRefExprBits.RefersToEnclosingVariableOrCapture =
        RefersToEnclosingVariableOrCapture;
    DeclRefExprBits.NonOdrUseReason = NOUR;
    DeclRefExprBits.Loc = L;
    computeDependence(Ctx);
  }
  
  DeclRefExpr::DeclRefExpr(const ASTContext &Ctx,
                           NestedNameSpecifierLoc QualifierLoc,
                           SourceLocation TemplateKWLoc, ValueDecl *D,
                           bool RefersToEnclosingVariableOrCapture,
                           const DeclarationNameInfo &NameInfo, NamedDecl *FoundD,
                           const TemplateArgumentListInfo *TemplateArgs,
                           QualType T, ExprValueKind VK, NonOdrUseReason NOUR)
      : Expr(DeclRefExprClass, T, VK, OK_Ordinary, false, false, false, false),
        D(D), DNLoc(NameInfo.getInfo()) {
    DeclRefExprBits.Loc = NameInfo.getLoc();
    DeclRefExprBits.HasQualifier = QualifierLoc ? 1 : 0;
    if (QualifierLoc) {
      new (getTrailingObjects<NestedNameSpecifierLoc>())
          NestedNameSpecifierLoc(QualifierLoc);
      auto *NNS = QualifierLoc.getNestedNameSpecifier();
      if (NNS->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (NNS->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
    }
    DeclRefExprBits.HasFoundDecl = FoundD ? 1 : 0;
    if (FoundD)
      *getTrailingObjects<NamedDecl *>() = FoundD;
    DeclRefExprBits.HasTemplateKWAndArgsInfo
      = (TemplateArgs || TemplateKWLoc.isValid()) ? 1 : 0;
    DeclRefExprBits.RefersToEnclosingVariableOrCapture =
        RefersToEnclosingVariableOrCapture;
    DeclRefExprBits.NonOdrUseReason = NOUR;
    if (TemplateArgs) {
      bool Dependent = false;
      bool InstantiationDependent = false;
      bool ContainsUnexpandedParameterPack = false;
      getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
          TemplateKWLoc, *TemplateArgs, getTrailingObjects<TemplateArgumentLoc>(),
          Dependent, InstantiationDependent, ContainsUnexpandedParameterPack);
      assert(!Dependent && "built a DeclRefExpr with dependent template args");
      ExprBits.InstantiationDependent |= InstantiationDependent;
      ExprBits.ContainsUnexpandedParameterPack |= ContainsUnexpandedParameterPack;
    } else if (TemplateKWLoc.isValid()) {
      getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
          TemplateKWLoc);
    }
    DeclRefExprBits.HadMultipleCandidates = 0;
  
    computeDependence(Ctx);
  }
  
  DeclRefExpr *DeclRefExpr::Create(const ASTContext &Context,
                                   NestedNameSpecifierLoc QualifierLoc,
                                   SourceLocation TemplateKWLoc, ValueDecl *D,
                                   bool RefersToEnclosingVariableOrCapture,
                                   SourceLocation NameLoc, QualType T,
                                   ExprValueKind VK, NamedDecl *FoundD,
                                   const TemplateArgumentListInfo *TemplateArgs,
                                   NonOdrUseReason NOUR) {
    return Create(Context, QualifierLoc, TemplateKWLoc, D,
                  RefersToEnclosingVariableOrCapture,
                  DeclarationNameInfo(D->getDeclName(), NameLoc),
                  T, VK, FoundD, TemplateArgs, NOUR);
  }
  
  DeclRefExpr *DeclRefExpr::Create(const ASTContext &Context,
                                   NestedNameSpecifierLoc QualifierLoc,
                                   SourceLocation TemplateKWLoc, ValueDecl *D,
                                   bool RefersToEnclosingVariableOrCapture,
                                   const DeclarationNameInfo &NameInfo,
                                   QualType T, ExprValueKind VK,
                                   NamedDecl *FoundD,
                                   const TemplateArgumentListInfo *TemplateArgs,
                                   NonOdrUseReason NOUR) {
    // Filter out cases where the found Decl is the same as the value refenenced.
    if (D == FoundD)
      FoundD = nullptr;
  
    bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
    std::size_t Size =
        totalSizeToAlloc<NestedNameSpecifierLoc, NamedDecl *,
                         ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
            QualifierLoc ? 1 : 0, FoundD ? 1 : 0,
            HasTemplateKWAndArgsInfo ? 1 : 0,
            TemplateArgs ? TemplateArgs->size() : 0);
  
    void *Mem = Context.Allocate(Size, alignof(DeclRefExpr));
    return new (Mem) DeclRefExpr(Context, QualifierLoc, TemplateKWLoc, D,
                                 RefersToEnclosingVariableOrCapture, NameInfo,
                                 FoundD, TemplateArgs, T, VK, NOUR);
  }
  
  DeclRefExpr *DeclRefExpr::CreateEmpty(const ASTContext &Context,
                                        bool HasQualifier,
                                        bool HasFoundDecl,
                                        bool HasTemplateKWAndArgsInfo,
                                        unsigned NumTemplateArgs) {
    assert(NumTemplateArgs == 0 || HasTemplateKWAndArgsInfo);
    std::size_t Size =
        totalSizeToAlloc<NestedNameSpecifierLoc, NamedDecl *,
                         ASTTemplateKWAndArgsInfo, TemplateArgumentLoc>(
            HasQualifier ? 1 : 0, HasFoundDecl ? 1 : 0, HasTemplateKWAndArgsInfo,
            NumTemplateArgs);
    void *Mem = Context.Allocate(Size, alignof(DeclRefExpr));
    return new (Mem) DeclRefExpr(EmptyShell());
  }
  
  SourceLocation DeclRefExpr::getBeginLoc() const {
    if (hasQualifier())
      return getQualifierLoc().getBeginLoc();
    return getNameInfo().getBeginLoc();
  }
  SourceLocation DeclRefExpr::getEndLoc() const {
    if (hasExplicitTemplateArgs())
      return getRAngleLoc();
    return getNameInfo().getEndLoc();
  }
  
  PredefinedExpr::PredefinedExpr(SourceLocation L, QualType FNTy, IdentKind IK,
                                 StringLiteral *SL)
      : Expr(PredefinedExprClass, FNTy, VK_LValue, OK_Ordinary,
             FNTy->isDependentType(), FNTy->isDependentType(),
             FNTy->isInstantiationDependentType(),
             /*ContainsUnexpandedParameterPack=*/false) {
    PredefinedExprBits.Kind = IK;
    assert((getIdentKind() == IK) &&
           "IdentKind do not fit in PredefinedExprBitfields!");
    bool HasFunctionName = SL != nullptr;
    PredefinedExprBits.HasFunctionName = HasFunctionName;
    PredefinedExprBits.Loc = L;
    if (HasFunctionName)
      setFunctionName(SL);
  }
  
  PredefinedExpr::PredefinedExpr(EmptyShell Empty, bool HasFunctionName)
      : Expr(PredefinedExprClass, Empty) {
    PredefinedExprBits.HasFunctionName = HasFunctionName;
  }
  
  PredefinedExpr *PredefinedExpr::Create(const ASTContext &Ctx, SourceLocation L,
                                         QualType FNTy, IdentKind IK,
                                         StringLiteral *SL) {
    bool HasFunctionName = SL != nullptr;
    void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(HasFunctionName),
                             alignof(PredefinedExpr));
    return new (Mem) PredefinedExpr(L, FNTy, IK, SL);
  }
  
  PredefinedExpr *PredefinedExpr::CreateEmpty(const ASTContext &Ctx,
                                              bool HasFunctionName) {
    void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(HasFunctionName),
                             alignof(PredefinedExpr));
    return new (Mem) PredefinedExpr(EmptyShell(), HasFunctionName);
  }
  
  StringRef PredefinedExpr::getIdentKindName(PredefinedExpr::IdentKind IK) {
    switch (IK) {
    case Func:
      return "__func__";
    case Function:
      return "__FUNCTION__";
    case FuncDName:
      return "__FUNCDNAME__";
    case LFunction:
      return "L__FUNCTION__";
    case PrettyFunction:
      return "__PRETTY_FUNCTION__";
    case FuncSig:
      return "__FUNCSIG__";
    case LFuncSig:
      return "L__FUNCSIG__";
    case PrettyFunctionNoVirtual:
      break;
    }
    llvm_unreachable("Unknown ident kind for PredefinedExpr");
  }
  
  // FIXME: Maybe this should use DeclPrinter with a special "print predefined
  // expr" policy instead.
  std::string PredefinedExpr::ComputeName(IdentKind IK, const Decl *CurrentDecl) {
    ASTContext &Context = CurrentDecl->getASTContext();
  
    if (IK == PredefinedExpr::FuncDName) {
      if (const NamedDecl *ND = dyn_cast<NamedDecl>(CurrentDecl)) {
        std::unique_ptr<MangleContext> MC;
        MC.reset(Context.createMangleContext());
  
        if (MC->shouldMangleDeclName(ND)) {
          SmallString<256> Buffer;
          llvm::raw_svector_ostream Out(Buffer);
          if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(ND))
            MC->mangleCXXCtor(CD, Ctor_Base, Out);
          else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(ND))
            MC->mangleCXXDtor(DD, Dtor_Base, Out);
          else
            MC->mangleName(ND, Out);
  
          if (!Buffer.empty() && Buffer.front() == '\01')
            return Buffer.substr(1);
          return Buffer.str();
        } else
          return ND->getIdentifier()->getName();
      }
      return "";
    }
    if (isa<BlockDecl>(CurrentDecl)) {
      // For blocks we only emit something if it is enclosed in a function
      // For top-level block we'd like to include the name of variable, but we
      // don't have it at this point.
      auto DC = CurrentDecl->getDeclContext();
      if (DC->isFileContext())
        return "";
  
      SmallString<256> Buffer;
      llvm::raw_svector_ostream Out(Buffer);
      if (auto *DCBlock = dyn_cast<BlockDecl>(DC))
        // For nested blocks, propagate up to the parent.
        Out << ComputeName(IK, DCBlock);
      else if (auto *DCDecl = dyn_cast<Decl>(DC))
        Out << ComputeName(IK, DCDecl) << "_block_invoke";
      return Out.str();
    }
    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurrentDecl)) {
      if (IK != PrettyFunction && IK != PrettyFunctionNoVirtual &&
          IK != FuncSig && IK != LFuncSig)
        return FD->getNameAsString();
  
      SmallString<256> Name;
      llvm::raw_svector_ostream Out(Name);
  
      if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
        if (MD->isVirtual() && IK != PrettyFunctionNoVirtual)
          Out << "virtual ";
        if (MD->isStatic())
          Out << "static ";
      }
  
      PrintingPolicy Policy(Context.getLangOpts());
      std::string Proto;
      llvm::raw_string_ostream POut(Proto);
  
      const FunctionDecl *Decl = FD;
      if (const FunctionDecl* Pattern = FD->getTemplateInstantiationPattern())
        Decl = Pattern;
      const FunctionType *AFT = Decl->getType()->getAs<FunctionType>();
      const FunctionProtoType *FT = nullptr;
      if (FD->hasWrittenPrototype())
        FT = dyn_cast<FunctionProtoType>(AFT);
  
      if (IK == FuncSig || IK == LFuncSig) {
        switch (AFT->getCallConv()) {
        case CC_C: POut << "__cdecl "; break;
        case CC_X86StdCall: POut << "__stdcall "; break;
        case CC_X86FastCall: POut << "__fastcall "; break;
        case CC_X86ThisCall: POut << "__thiscall "; break;
        case CC_X86VectorCall: POut << "__vectorcall "; break;
        case CC_X86RegCall: POut << "__regcall "; break;
        // Only bother printing the conventions that MSVC knows about.
        default: break;
        }
      }
  
      FD->printQualifiedName(POut, Policy);
  
      POut << "(";
      if (FT) {
        for (unsigned i = 0, e = Decl->getNumParams(); i != e; ++i) {
          if (i) POut << ", ";
          POut << Decl->getParamDecl(i)->getType().stream(Policy);
        }
  
        if (FT->isVariadic()) {
          if (FD->getNumParams()) POut << ", ";
          POut << "...";
        } else if ((IK == FuncSig || IK == LFuncSig ||
                    !Context.getLangOpts().CPlusPlus) &&
                   !Decl->getNumParams()) {
          POut << "void";
        }
      }
      POut << ")";
  
      if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD)) {
        assert(FT && "We must have a written prototype in this case.");
        if (FT->isConst())
          POut << " const";
        if (FT->isVolatile())
          POut << " volatile";
        RefQualifierKind Ref = MD->getRefQualifier();
        if (Ref == RQ_LValue)
          POut << " &";
        else if (Ref == RQ_RValue)
          POut << " &&";
      }
  
      typedef SmallVector<const ClassTemplateSpecializationDecl *, 8> SpecsTy;
      SpecsTy Specs;
      const DeclContext *Ctx = FD->getDeclContext();
      while (Ctx && isa<NamedDecl>(Ctx)) {
        const ClassTemplateSpecializationDecl *Spec
                                 = dyn_cast<ClassTemplateSpecializationDecl>(Ctx);
        if (Spec && !Spec->isExplicitSpecialization())
          Specs.push_back(Spec);
        Ctx = Ctx->getParent();
      }
  
      std::string TemplateParams;
      llvm::raw_string_ostream TOut(TemplateParams);
      for (SpecsTy::reverse_iterator I = Specs.rbegin(), E = Specs.rend();
           I != E; ++I) {
        const TemplateParameterList *Params
                    = (*I)->getSpecializedTemplate()->getTemplateParameters();
        const TemplateArgumentList &Args = (*I)->getTemplateArgs();
        assert(Params->size() == Args.size());
        for (unsigned i = 0, numParams = Params->size(); i != numParams; ++i) {
          StringRef Param = Params->getParam(i)->getName();
          if (Param.empty()) continue;
          TOut << Param << " = ";
          Args.get(i).print(Policy, TOut);
          TOut << ", ";
        }
      }
  
      FunctionTemplateSpecializationInfo *FSI
                                            = FD->getTemplateSpecializationInfo();
      if (FSI && !FSI->isExplicitSpecialization()) {
        const TemplateParameterList* Params
                                    = FSI->getTemplate()->getTemplateParameters();
        const TemplateArgumentList* Args = FSI->TemplateArguments;
        assert(Params->size() == Args->size());
        for (unsigned i = 0, e = Params->size(); i != e; ++i) {
          StringRef Param = Params->getParam(i)->getName();
          if (Param.empty()) continue;
          TOut << Param << " = ";
          Args->get(i).print(Policy, TOut);
          TOut << ", ";
        }
      }
  
      TOut.flush();
      if (!TemplateParams.empty()) {
        // remove the trailing comma and space
        TemplateParams.resize(TemplateParams.size() - 2);
        POut << " [" << TemplateParams << "]";
      }
  
      POut.flush();
  
      // Print "auto" for all deduced return types. This includes C++1y return
      // type deduction and lambdas. For trailing return types resolve the
      // decltype expression. Otherwise print the real type when this is
      // not a constructor or destructor.
      if (isa<CXXMethodDecl>(FD) &&
           cast<CXXMethodDecl>(FD)->getParent()->isLambda())
        Proto = "auto " + Proto;
      else if (FT && FT->getReturnType()->getAs<DecltypeType>())
        FT->getReturnType()
            ->getAs<DecltypeType>()
            ->getUnderlyingType()
            .getAsStringInternal(Proto, Policy);
      else if (!isa<CXXConstructorDecl>(FD) && !isa<CXXDestructorDecl>(FD))
        AFT->getReturnType().getAsStringInternal(Proto, Policy);
  
      Out << Proto;
  
      return Name.str().str();
    }
    if (const CapturedDecl *CD = dyn_cast<CapturedDecl>(CurrentDecl)) {
      for (const DeclContext *DC = CD->getParent(); DC; DC = DC->getParent())
        // Skip to its enclosing function or method, but not its enclosing
        // CapturedDecl.
        if (DC->isFunctionOrMethod() && (DC->getDeclKind() != Decl::Captured)) {
          const Decl *D = Decl::castFromDeclContext(DC);
          return ComputeName(IK, D);
        }
      llvm_unreachable("CapturedDecl not inside a function or method");
    }
    if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(CurrentDecl)) {
      SmallString<256> Name;
      llvm::raw_svector_ostream Out(Name);
      Out << (MD->isInstanceMethod() ? '-' : '+');
      Out << '[';
  
      // For incorrect code, there might not be an ObjCInterfaceDecl.  Do
      // a null check to avoid a crash.
      if (const ObjCInterfaceDecl *ID = MD->getClassInterface())
        Out << *ID;
  
      if (const ObjCCategoryImplDecl *CID =
          dyn_cast<ObjCCategoryImplDecl>(MD->getDeclContext()))
        Out << '(' << *CID << ')';
  
      Out <<  ' ';
      MD->getSelector().print(Out);
      Out <<  ']';
  
      return Name.str().str();
    }
    if (isa<TranslationUnitDecl>(CurrentDecl) && IK == PrettyFunction) {
      // __PRETTY_FUNCTION__ -> "top level", the others produce an empty string.
      return "top level";
    }
    return "";
  }
  
  void APNumericStorage::setIntValue(const ASTContext &C,
                                     const llvm::APInt &Val) {
    if (hasAllocation())
      C.Deallocate(pVal);
  
    BitWidth = Val.getBitWidth();
    unsigned NumWords = Val.getNumWords();
    const uint64_t* Words = Val.getRawData();
    if (NumWords > 1) {
      pVal = new (C) uint64_t[NumWords];
      std::copy(Words, Words + NumWords, pVal);
    } else if (NumWords == 1)
      VAL = Words[0];
    else
      VAL = 0;
  }
  
  IntegerLiteral::IntegerLiteral(const ASTContext &C, const llvm::APInt &V,
                                 QualType type, SourceLocation l)
    : Expr(IntegerLiteralClass, type, VK_RValue, OK_Ordinary, false, false,
           false, false),
      Loc(l) {
    assert(type->isIntegerType() && "Illegal type in IntegerLiteral");
    assert(V.getBitWidth() == C.getIntWidth(type) &&
           "Integer type is not the correct size for constant.");
    setValue(C, V);
  }
  
  IntegerLiteral *
  IntegerLiteral::Create(const ASTContext &C, const llvm::APInt &V,
                         QualType type, SourceLocation l) {
    return new (C) IntegerLiteral(C, V, type, l);
  }
  
  IntegerLiteral *
  IntegerLiteral::Create(const ASTContext &C, EmptyShell Empty) {
    return new (C) IntegerLiteral(Empty);
  }
  
  FixedPointLiteral::FixedPointLiteral(const ASTContext &C, const llvm::APInt &V,
                                       QualType type, SourceLocation l,
                                       unsigned Scale)
      : Expr(FixedPointLiteralClass, type, VK_RValue, OK_Ordinary, false, false,
             false, false),
        Loc(l), Scale(Scale) {
    assert(type->isFixedPointType() && "Illegal type in FixedPointLiteral");
    assert(V.getBitWidth() == C.getTypeInfo(type).Width &&
           "Fixed point type is not the correct size for constant.");
    setValue(C, V);
  }
  
  FixedPointLiteral *FixedPointLiteral::CreateFromRawInt(const ASTContext &C,
                                                         const llvm::APInt &V,
                                                         QualType type,
                                                         SourceLocation l,
                                                         unsigned Scale) {
    return new (C) FixedPointLiteral(C, V, type, l, Scale);
  }
  
  std::string FixedPointLiteral::getValueAsString(unsigned Radix) const {
    // Currently the longest decimal number that can be printed is the max for an
    // unsigned long _Accum: 4294967295.99999999976716935634613037109375
    // which is 43 characters.
    SmallString<64> S;
    FixedPointValueToString(
        S, llvm::APSInt::getUnsigned(getValue().getZExtValue()), Scale);
    return S.str();
  }
  
  FloatingLiteral::FloatingLiteral(const ASTContext &C, const llvm::APFloat &V,
                                   bool isexact, QualType Type, SourceLocation L)
    : Expr(FloatingLiteralClass, Type, VK_RValue, OK_Ordinary, false, false,
           false, false), Loc(L) {
    setSemantics(V.getSemantics());
    FloatingLiteralBits.IsExact = isexact;
    setValue(C, V);
  }
  
  FloatingLiteral::FloatingLiteral(const ASTContext &C, EmptyShell Empty)
    : Expr(FloatingLiteralClass, Empty) {
    setRawSemantics(llvm::APFloatBase::S_IEEEhalf);
    FloatingLiteralBits.IsExact = false;
  }
  
  FloatingLiteral *
  FloatingLiteral::Create(const ASTContext &C, const llvm::APFloat &V,
                          bool isexact, QualType Type, SourceLocation L) {
    return new (C) FloatingLiteral(C, V, isexact, Type, L);
  }
  
  FloatingLiteral *
  FloatingLiteral::Create(const ASTContext &C, EmptyShell Empty) {
    return new (C) FloatingLiteral(C, Empty);
  }
  
  /// getValueAsApproximateDouble - This returns the value as an inaccurate
  /// double.  Note that this may cause loss of precision, but is useful for
  /// debugging dumps, etc.
  double FloatingLiteral::getValueAsApproximateDouble() const {
    llvm::APFloat V = getValue();
    bool ignored;
    V.convert(llvm::APFloat::IEEEdouble(), llvm::APFloat::rmNearestTiesToEven,
              &ignored);
    return V.convertToDouble();
  }
  
  unsigned StringLiteral::mapCharByteWidth(TargetInfo const &Target,
                                           StringKind SK) {
    unsigned CharByteWidth = 0;
    switch (SK) {
    case Ascii:
    case UTF8:
      CharByteWidth = Target.getCharWidth();
      break;
    case Wide:
      CharByteWidth = Target.getWCharWidth();
      break;
    case UTF16:
      CharByteWidth = Target.getChar16Width();
      break;
    case UTF32:
      CharByteWidth = Target.getChar32Width();
      break;
    }
    assert((CharByteWidth & 7) == 0 && "Assumes character size is byte multiple");
    CharByteWidth /= 8;
    assert((CharByteWidth == 1 || CharByteWidth == 2 || CharByteWidth == 4) &&
           "The only supported character byte widths are 1,2 and 4!");
    return CharByteWidth;
  }
  
  StringLiteral::StringLiteral(const ASTContext &Ctx, StringRef Str,
                               StringKind Kind, bool Pascal, QualType Ty,
                               const SourceLocation *Loc,
                               unsigned NumConcatenated)
      : Expr(StringLiteralClass, Ty, VK_LValue, OK_Ordinary, false, false, false,
             false) {
    assert(Ctx.getAsConstantArrayType(Ty) &&
           "StringLiteral must be of constant array type!");
    unsigned CharByteWidth = mapCharByteWidth(Ctx.getTargetInfo(), Kind);
    unsigned ByteLength = Str.size();
    assert((ByteLength % CharByteWidth == 0) &&
           "The size of the data must be a multiple of CharByteWidth!");
  
    // Avoid the expensive division. The compiler should be able to figure it
    // out by itself. However as of clang 7, even with the appropriate
    // llvm_unreachable added just here, it is not able to do so.
    unsigned Length;
    switch (CharByteWidth) {
    case 1:
      Length = ByteLength;
      break;
    case 2:
      Length = ByteLength / 2;
      break;
    case 4:
      Length = ByteLength / 4;
      break;
    default:
      llvm_unreachable("Unsupported character width!");
    }
  
    StringLiteralBits.Kind = Kind;
    StringLiteralBits.CharByteWidth = CharByteWidth;
    StringLiteralBits.IsPascal = Pascal;
    StringLiteralBits.NumConcatenated = NumConcatenated;
    *getTrailingObjects<unsigned>() = Length;
  
    // Initialize the trailing array of SourceLocation.
    // This is safe since SourceLocation is POD-like.
    std::memcpy(getTrailingObjects<SourceLocation>(), Loc,
                NumConcatenated * sizeof(SourceLocation));
  
    // Initialize the trailing array of char holding the string data.
    std::memcpy(getTrailingObjects<char>(), Str.data(), ByteLength);
  }
  
  StringLiteral::StringLiteral(EmptyShell Empty, unsigned NumConcatenated,
                               unsigned Length, unsigned CharByteWidth)
      : Expr(StringLiteralClass, Empty) {
    StringLiteralBits.CharByteWidth = CharByteWidth;
    StringLiteralBits.NumConcatenated = NumConcatenated;
    *getTrailingObjects<unsigned>() = Length;
  }
  
  StringLiteral *StringLiteral::Create(const ASTContext &Ctx, StringRef Str,
                                       StringKind Kind, bool Pascal, QualType Ty,
                                       const SourceLocation *Loc,
                                       unsigned NumConcatenated) {
    void *Mem = Ctx.Allocate(totalSizeToAlloc<unsigned, SourceLocation, char>(
                                 1, NumConcatenated, Str.size()),
                             alignof(StringLiteral));
    return new (Mem)
        StringLiteral(Ctx, Str, Kind, Pascal, Ty, Loc, NumConcatenated);
  }
  
  StringLiteral *StringLiteral::CreateEmpty(const ASTContext &Ctx,
                                            unsigned NumConcatenated,
                                            unsigned Length,
                                            unsigned CharByteWidth) {
    void *Mem = Ctx.Allocate(totalSizeToAlloc<unsigned, SourceLocation, char>(
                                 1, NumConcatenated, Length * CharByteWidth),
                             alignof(StringLiteral));
    return new (Mem)
        StringLiteral(EmptyShell(), NumConcatenated, Length, CharByteWidth);
  }
  
  void StringLiteral::outputString(raw_ostream &OS) const {
    switch (getKind()) {
    case Ascii: break; // no prefix.
    case Wide:  OS << 'L'; break;
    case UTF8:  OS << "u8"; break;
    case UTF16: OS << 'u'; break;
    case UTF32: OS << 'U'; break;
    }
    OS << '"';
    static const char Hex[] = "0123456789ABCDEF";
  
    unsigned LastSlashX = getLength();
    for (unsigned I = 0, N = getLength(); I != N; ++I) {
      switch (uint32_t Char = getCodeUnit(I)) {
      default:
        // FIXME: Convert UTF-8 back to codepoints before rendering.
  
        // Convert UTF-16 surrogate pairs back to codepoints before rendering.
        // Leave invalid surrogates alone; we'll use \x for those.
        if (getKind() == UTF16 && I != N - 1 && Char >= 0xd800 &&
            Char <= 0xdbff) {
          uint32_t Trail = getCodeUnit(I + 1);
          if (Trail >= 0xdc00 && Trail <= 0xdfff) {
            Char = 0x10000 + ((Char - 0xd800) << 10) + (Trail - 0xdc00);
            ++I;
          }
        }
  
        if (Char > 0xff) {
          // If this is a wide string, output characters over 0xff using \x
          // escapes. Otherwise, this is a UTF-16 or UTF-32 string, and Char is a
          // codepoint: use \x escapes for invalid codepoints.
          if (getKind() == Wide ||
              (Char >= 0xd800 && Char <= 0xdfff) || Char >= 0x110000) {
            // FIXME: Is this the best way to print wchar_t?
            OS << "\\x";
            int Shift = 28;
            while ((Char >> Shift) == 0)
              Shift -= 4;
            for (/**/; Shift >= 0; Shift -= 4)
              OS << Hex[(Char >> Shift) & 15];
            LastSlashX = I;
            break;
          }
  
          if (Char > 0xffff)
            OS << "\\U00"
               << Hex[(Char >> 20) & 15]
               << Hex[(Char >> 16) & 15];
          else
            OS << "\\u";
          OS << Hex[(Char >> 12) & 15]
             << Hex[(Char >>  8) & 15]
             << Hex[(Char >>  4) & 15]
             << Hex[(Char >>  0) & 15];
          break;
        }
  
        // If we used \x... for the previous character, and this character is a
        // hexadecimal digit, prevent it being slurped as part of the \x.
        if (LastSlashX + 1 == I) {
          switch (Char) {
            case '0': case '1': case '2': case '3': case '4':
            case '5': case '6': case '7': case '8': case '9':
            case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
            case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
              OS << "\"\"";
          }
        }
  
        assert(Char <= 0xff &&
               "Characters above 0xff should already have been handled.");
  
        if (isPrintable(Char))
          OS << (char)Char;
        else  // Output anything hard as an octal escape.
          OS << '\\'
             << (char)('0' + ((Char >> 6) & 7))
             << (char)('0' + ((Char >> 3) & 7))
             << (char)('0' + ((Char >> 0) & 7));
        break;
      // Handle some common non-printable cases to make dumps prettier.
      case '\\': OS << "\\\\"; break;
      case '"': OS << "\\\""; break;
      case '\a': OS << "\\a"; break;
      case '\b': OS << "\\b"; break;
      case '\f': OS << "\\f"; break;
      case '\n': OS << "\\n"; break;
      case '\r': OS << "\\r"; break;
      case '\t': OS << "\\t"; break;
      case '\v': OS << "\\v"; break;
      }
    }
    OS << '"';
  }
  
  /// getLocationOfByte - Return a source location that points to the specified
  /// byte of this string literal.
  ///
  /// Strings are amazingly complex.  They can be formed from multiple tokens and
  /// can have escape sequences in them in addition to the usual trigraph and
  /// escaped newline business.  This routine handles this complexity.
  ///
  /// The *StartToken sets the first token to be searched in this function and
  /// the *StartTokenByteOffset is the byte offset of the first token. Before
  /// returning, it updates the *StartToken to the TokNo of the token being found
  /// and sets *StartTokenByteOffset to the byte offset of the token in the
  /// string.
  /// Using these two parameters can reduce the time complexity from O(n^2) to
  /// O(n) if one wants to get the location of byte for all the tokens in a
  /// string.
  ///
  SourceLocation
  StringLiteral::getLocationOfByte(unsigned ByteNo, const SourceManager &SM,
                                   const LangOptions &Features,
                                   const TargetInfo &Target, unsigned *StartToken,
                                   unsigned *StartTokenByteOffset) const {
    assert((getKind() == StringLiteral::Ascii ||
            getKind() == StringLiteral::UTF8) &&
           "Only narrow string literals are currently supported");
  
    // Loop over all of the tokens in this string until we find the one that
    // contains the byte we're looking for.
    unsigned TokNo = 0;
    unsigned StringOffset = 0;
    if (StartToken)
      TokNo = *StartToken;
    if (StartTokenByteOffset) {
      StringOffset = *StartTokenByteOffset;
      ByteNo -= StringOffset;
    }
    while (1) {
      assert(TokNo < getNumConcatenated() && "Invalid byte number!");
      SourceLocation StrTokLoc = getStrTokenLoc(TokNo);
  
      // Get the spelling of the string so that we can get the data that makes up
      // the string literal, not the identifier for the macro it is potentially
      // expanded through.
      SourceLocation StrTokSpellingLoc = SM.getSpellingLoc(StrTokLoc);
  
      // Re-lex the token to get its length and original spelling.
      std::pair<FileID, unsigned> LocInfo =
          SM.getDecomposedLoc(StrTokSpellingLoc);
      bool Invalid = false;
      StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);
      if (Invalid) {
        if (StartTokenByteOffset != nullptr)
          *StartTokenByteOffset = StringOffset;
        if (StartToken != nullptr)
          *StartToken = TokNo;
        return StrTokSpellingLoc;
      }
  
      const char *StrData = Buffer.data()+LocInfo.second;
  
      // Create a lexer starting at the beginning of this token.
      Lexer TheLexer(SM.getLocForStartOfFile(LocInfo.first), Features,
                     Buffer.begin(), StrData, Buffer.end());
      Token TheTok;
      TheLexer.LexFromRawLexer(TheTok);
  
      // Use the StringLiteralParser to compute the length of the string in bytes.
      StringLiteralParser SLP(TheTok, SM, Features, Target);
      unsigned TokNumBytes = SLP.GetStringLength();
  
      // If the byte is in this token, return the location of the byte.
      if (ByteNo < TokNumBytes ||
          (ByteNo == TokNumBytes && TokNo == getNumConcatenated() - 1)) {
        unsigned Offset = SLP.getOffsetOfStringByte(TheTok, ByteNo);
  
        // Now that we know the offset of the token in the spelling, use the
        // preprocessor to get the offset in the original source.
        if (StartTokenByteOffset != nullptr)
          *StartTokenByteOffset = StringOffset;
        if (StartToken != nullptr)
          *StartToken = TokNo;
        return Lexer::AdvanceToTokenCharacter(StrTokLoc, Offset, SM, Features);
      }
  
      // Move to the next string token.
      StringOffset += TokNumBytes;
      ++TokNo;
      ByteNo -= TokNumBytes;
    }
  }
  
  /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
  /// corresponds to, e.g. "sizeof" or "[pre]++".
  StringRef UnaryOperator::getOpcodeStr(Opcode Op) {
    switch (Op) {
  #define UNARY_OPERATION(Name, Spelling) case UO_##Name: return Spelling;
  #include "clang/AST/OperationKinds.def"
    }
    llvm_unreachable("Unknown unary operator");
  }
  
  UnaryOperatorKind
  UnaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO, bool Postfix) {
    switch (OO) {
    default: llvm_unreachable("No unary operator for overloaded function");
    case OO_PlusPlus:   return Postfix ? UO_PostInc : UO_PreInc;
    case OO_MinusMinus: return Postfix ? UO_PostDec : UO_PreDec;
    case OO_Amp:        return UO_AddrOf;
    case OO_Star:       return UO_Deref;
    case OO_Plus:       return UO_Plus;
    case OO_Minus:      return UO_Minus;
    case OO_Tilde:      return UO_Not;
    case OO_Exclaim:    return UO_LNot;
    case OO_Coawait:    return UO_Coawait;
    }
  }
  
  OverloadedOperatorKind UnaryOperator::getOverloadedOperator(Opcode Opc) {
    switch (Opc) {
    case UO_PostInc: case UO_PreInc: return OO_PlusPlus;
    case UO_PostDec: case UO_PreDec: return OO_MinusMinus;
    case UO_AddrOf: return OO_Amp;
    case UO_Deref: return OO_Star;
    case UO_Plus: return OO_Plus;
    case UO_Minus: return OO_Minus;
    case UO_Not: return OO_Tilde;
    case UO_LNot: return OO_Exclaim;
    case UO_Coawait: return OO_Coawait;
    default: return OO_None;
    }
  }
  
  
  //===----------------------------------------------------------------------===//
  // Postfix Operators.
  //===----------------------------------------------------------------------===//
  
  CallExpr::CallExpr(StmtClass SC, Expr *Fn, ArrayRef<Expr *> PreArgs,
                     ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
                     SourceLocation RParenLoc, unsigned MinNumArgs,
                     ADLCallKind UsesADL)
      : Expr(SC, Ty, VK, OK_Ordinary, Fn->isTypeDependent(),
             Fn->isValueDependent(), Fn->isInstantiationDependent(),
             Fn->containsUnexpandedParameterPack()),
        RParenLoc(RParenLoc) {
    NumArgs = std::max<unsigned>(Args.size(), MinNumArgs);
    unsigned NumPreArgs = PreArgs.size();
    CallExprBits.NumPreArgs = NumPreArgs;
    assert((NumPreArgs == getNumPreArgs()) && "NumPreArgs overflow!");
  
    unsigned OffsetToTrailingObjects = offsetToTrailingObjects(SC);
    CallExprBits.OffsetToTrailingObjects = OffsetToTrailingObjects;
    assert((CallExprBits.OffsetToTrailingObjects == OffsetToTrailingObjects) &&
           "OffsetToTrailingObjects overflow!");
  
    CallExprBits.UsesADL = static_cast<bool>(UsesADL);
  
    setCallee(Fn);
    for (unsigned I = 0; I != NumPreArgs; ++I) {
      updateDependenciesFromArg(PreArgs[I]);
      setPreArg(I, PreArgs[I]);
    }
    for (unsigned I = 0; I != Args.size(); ++I) {
      updateDependenciesFromArg(Args[I]);
      setArg(I, Args[I]);
    }
    for (unsigned I = Args.size(); I != NumArgs; ++I) {
      setArg(I, nullptr);
    }
  }
  
  CallExpr::CallExpr(StmtClass SC, unsigned NumPreArgs, unsigned NumArgs,
                     EmptyShell Empty)
      : Expr(SC, Empty), NumArgs(NumArgs) {
    CallExprBits.NumPreArgs = NumPreArgs;
    assert((NumPreArgs == getNumPreArgs()) && "NumPreArgs overflow!");
  
    unsigned OffsetToTrailingObjects = offsetToTrailingObjects(SC);
    CallExprBits.OffsetToTrailingObjects = OffsetToTrailingObjects;
    assert((CallExprBits.OffsetToTrailingObjects == OffsetToTrailingObjects) &&
           "OffsetToTrailingObjects overflow!");
  }
  
  CallExpr *CallExpr::Create(const ASTContext &Ctx, Expr *Fn,
                             ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
                             SourceLocation RParenLoc, unsigned MinNumArgs,
                             ADLCallKind UsesADL) {
    unsigned NumArgs = std::max<unsigned>(Args.size(), MinNumArgs);
    unsigned SizeOfTrailingObjects =
        CallExpr::sizeOfTrailingObjects(/*NumPreArgs=*/0, NumArgs);
    void *Mem =
        Ctx.Allocate(sizeof(CallExpr) + SizeOfTrailingObjects, alignof(CallExpr));
    return new (Mem) CallExpr(CallExprClass, Fn, /*PreArgs=*/{}, Args, Ty, VK,
                              RParenLoc, MinNumArgs, UsesADL);
  }
  
  CallExpr *CallExpr::CreateTemporary(void *Mem, Expr *Fn, QualType Ty,
                                      ExprValueKind VK, SourceLocation RParenLoc,
                                      ADLCallKind UsesADL) {
    assert(!(reinterpret_cast<uintptr_t>(Mem) % alignof(CallExpr)) &&
           "Misaligned memory in CallExpr::CreateTemporary!");
    return new (Mem) CallExpr(CallExprClass, Fn, /*PreArgs=*/{}, /*Args=*/{}, Ty,
                              VK, RParenLoc, /*MinNumArgs=*/0, UsesADL);
  }
  
  CallExpr *CallExpr::CreateEmpty(const ASTContext &Ctx, unsigned NumArgs,
                                  EmptyShell Empty) {
    unsigned SizeOfTrailingObjects =
        CallExpr::sizeOfTrailingObjects(/*NumPreArgs=*/0, NumArgs);
    void *Mem =
        Ctx.Allocate(sizeof(CallExpr) + SizeOfTrailingObjects, alignof(CallExpr));
    return new (Mem) CallExpr(CallExprClass, /*NumPreArgs=*/0, NumArgs, Empty);
  }
  
  unsigned CallExpr::offsetToTrailingObjects(StmtClass SC) {
    switch (SC) {
    case CallExprClass:
      return sizeof(CallExpr);
    case CXXOperatorCallExprClass:
      return sizeof(CXXOperatorCallExpr);
    case CXXMemberCallExprClass:
      return sizeof(CXXMemberCallExpr);
    case UserDefinedLiteralClass:
      return sizeof(UserDefinedLiteral);
    case CUDAKernelCallExprClass:
      return sizeof(CUDAKernelCallExpr);
    default:
      llvm_unreachable("unexpected class deriving from CallExpr!");
    }
  }
  
  void CallExpr::updateDependenciesFromArg(Expr *Arg) {
    if (Arg->isTypeDependent())
      ExprBits.TypeDependent = true;
    if (Arg->isValueDependent())
      ExprBits.ValueDependent = true;
    if (Arg->isInstantiationDependent())
      ExprBits.InstantiationDependent = true;
    if (Arg->containsUnexpandedParameterPack())
      ExprBits.ContainsUnexpandedParameterPack = true;
  }
  
  Decl *Expr::getReferencedDeclOfCallee() {
    Expr *CEE = IgnoreParenImpCasts();
  
    while (SubstNonTypeTemplateParmExpr *NTTP
                                  = dyn_cast<SubstNonTypeTemplateParmExpr>(CEE)) {
      CEE = NTTP->getReplacement()->IgnoreParenCasts();
    }
  
    // If we're calling a dereference, look at the pointer instead.
    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(CEE)) {
      if (BO->isPtrMemOp())
        CEE = BO->getRHS()->IgnoreParenCasts();
    } else if (UnaryOperator *UO = dyn_cast<UnaryOperator>(CEE)) {
      if (UO->getOpcode() == UO_Deref)
        CEE = UO->getSubExpr()->IgnoreParenCasts();
    }
    if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE))
      return DRE->getDecl();
    if (MemberExpr *ME = dyn_cast<MemberExpr>(CEE))
      return ME->getMemberDecl();
    if (auto *BE = dyn_cast<BlockExpr>(CEE))
      return BE->getBlockDecl();
  
    return nullptr;
  }
  
  /// getBuiltinCallee - If this is a call to a builtin, return the builtin ID. If
  /// not, return 0.
  unsigned CallExpr::getBuiltinCallee() const {
    // All simple function calls (e.g. func()) are implicitly cast to pointer to
    // function. As a result, we try and obtain the DeclRefExpr from the
    // ImplicitCastExpr.
    const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(getCallee());
    if (!ICE) // FIXME: deal with more complex calls (e.g. (func)(), (*func)()).
      return 0;
  
    const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr());
    if (!DRE)
      return 0;
  
    const FunctionDecl *FDecl = dyn_cast<FunctionDecl>(DRE->getDecl());
    if (!FDecl)
      return 0;
  
    if (!FDecl->getIdentifier())
      return 0;
  
    return FDecl->getBuiltinID();
  }
  
  bool CallExpr::isUnevaluatedBuiltinCall(const ASTContext &Ctx) const {
    if (unsigned BI = getBuiltinCallee())
      return Ctx.BuiltinInfo.isUnevaluated(BI);
    return false;
  }
  
  QualType CallExpr::getCallReturnType(const ASTContext &Ctx) const {
    const Expr *Callee = getCallee();
    QualType CalleeType = Callee->getType();
    if (const auto *FnTypePtr = CalleeType->getAs<PointerType>()) {
      CalleeType = FnTypePtr->getPointeeType();
    } else if (const auto *BPT = CalleeType->getAs<BlockPointerType>()) {
      CalleeType = BPT->getPointeeType();
    } else if (CalleeType->isSpecificPlaceholderType(BuiltinType::BoundMember)) {
      if (isa<CXXPseudoDestructorExpr>(Callee->IgnoreParens()))
        return Ctx.VoidTy;
  
      // This should never be overloaded and so should never return null.
      CalleeType = Expr::findBoundMemberType(Callee);
    }
  
    const FunctionType *FnType = CalleeType->castAs<FunctionType>();
    return FnType->getReturnType();
  }
  
  const Attr *CallExpr::getUnusedResultAttr(const ASTContext &Ctx) const {
    // If the return type is a struct, union, or enum that is marked nodiscard,
    // then return the return type attribute.
    if (const TagDecl *TD = getCallReturnType(Ctx)->getAsTagDecl())
      if (const auto *A = TD->getAttr<WarnUnusedResultAttr>())
        return A;
  
    // Otherwise, see if the callee is marked nodiscard and return that attribute
    // instead.
    const Decl *D = getCalleeDecl();
    return D ? D->getAttr<WarnUnusedResultAttr>() : nullptr;
  }
  
  SourceLocation CallExpr::getBeginLoc() const {
    if (isa<CXXOperatorCallExpr>(this))
      return cast<CXXOperatorCallExpr>(this)->getBeginLoc();
  
    SourceLocation begin = getCallee()->getBeginLoc();
    if (begin.isInvalid() && getNumArgs() > 0 && getArg(0))
      begin = getArg(0)->getBeginLoc();
    return begin;
  }
  SourceLocation CallExpr::getEndLoc() const {
    if (isa<CXXOperatorCallExpr>(this))
      return cast<CXXOperatorCallExpr>(this)->getEndLoc();
  
    SourceLocation end = getRParenLoc();
    if (end.isInvalid() && getNumArgs() > 0 && getArg(getNumArgs() - 1))
      end = getArg(getNumArgs() - 1)->getEndLoc();
    return end;
  }
  
  OffsetOfExpr *OffsetOfExpr::Create(const ASTContext &C, QualType type,
                                     SourceLocation OperatorLoc,
                                     TypeSourceInfo *tsi,
                                     ArrayRef<OffsetOfNode> comps,
                                     ArrayRef<Expr*> exprs,
                                     SourceLocation RParenLoc) {
    void *Mem = C.Allocate(
        totalSizeToAlloc<OffsetOfNode, Expr *>(comps.size(), exprs.size()));
  
    return new (Mem) OffsetOfExpr(C, type, OperatorLoc, tsi, comps, exprs,
                                  RParenLoc);
  }
  
  OffsetOfExpr *OffsetOfExpr::CreateEmpty(const ASTContext &C,
                                          unsigned numComps, unsigned numExprs) {
    void *Mem =
        C.Allocate(totalSizeToAlloc<OffsetOfNode, Expr *>(numComps, numExprs));
    return new (Mem) OffsetOfExpr(numComps, numExprs);
  }
  
  OffsetOfExpr::OffsetOfExpr(const ASTContext &C, QualType type,
                             SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                             ArrayRef<OffsetOfNode> comps, ArrayRef<Expr*> exprs,
                             SourceLocation RParenLoc)
    : Expr(OffsetOfExprClass, type, VK_RValue, OK_Ordinary,
           /*TypeDependent=*/false,
           /*ValueDependent=*/tsi->getType()->isDependentType(),
           tsi->getType()->isInstantiationDependentType(),
           tsi->getType()->containsUnexpandedParameterPack()),
      OperatorLoc(OperatorLoc), RParenLoc(RParenLoc), TSInfo(tsi),
      NumComps(comps.size()), NumExprs(exprs.size())
  {
    for (unsigned i = 0; i != comps.size(); ++i) {
      setComponent(i, comps[i]);
    }
  
    for (unsigned i = 0; i != exprs.size(); ++i) {
      if (exprs[i]->isTypeDependent() || exprs[i]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (exprs[i]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
  
      setIndexExpr(i, exprs[i]);
    }
  }
  
  IdentifierInfo *OffsetOfNode::getFieldName() const {
    assert(getKind() == Field || getKind() == Identifier);
    if (getKind() == Field)
      return getField()->getIdentifier();
  
    return reinterpret_cast<IdentifierInfo *> (Data & ~(uintptr_t)Mask);
  }
  
  UnaryExprOrTypeTraitExpr::UnaryExprOrTypeTraitExpr(
      UnaryExprOrTypeTrait ExprKind, Expr *E, QualType resultType,
      SourceLocation op, SourceLocation rp)
      : Expr(UnaryExprOrTypeTraitExprClass, resultType, VK_RValue, OK_Ordinary,
             false, // Never type-dependent (C++ [temp.dep.expr]p3).
             // Value-dependent if the argument is type-dependent.
             E->isTypeDependent(), E->isInstantiationDependent(),
             E->containsUnexpandedParameterPack()),
        OpLoc(op), RParenLoc(rp) {
    UnaryExprOrTypeTraitExprBits.Kind = ExprKind;
    UnaryExprOrTypeTraitExprBits.IsType = false;
    Argument.Ex = E;
  
    // Check to see if we are in the situation where alignof(decl) should be
    // dependent because decl's alignment is dependent.
    if (ExprKind == UETT_AlignOf || ExprKind == UETT_PreferredAlignOf) {
      if (!isValueDependent() || !isInstantiationDependent()) {
        E = E->IgnoreParens();
  
        const ValueDecl *D = nullptr;
        if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
          D = DRE->getDecl();
        else if (const auto *ME = dyn_cast<MemberExpr>(E))
          D = ME->getMemberDecl();
  
        if (D) {
          for (const auto *I : D->specific_attrs<AlignedAttr>()) {
            if (I->isAlignmentDependent()) {
              setValueDependent(true);
              setInstantiationDependent(true);
              break;
            }
          }
        }
      }
    }
  }
  
  MemberExpr::MemberExpr(Expr *Base, bool IsArrow, SourceLocation OperatorLoc,
                         ValueDecl *MemberDecl,
                         const DeclarationNameInfo &NameInfo, QualType T,
                         ExprValueKind VK, ExprObjectKind OK,
                         NonOdrUseReason NOUR)
      : Expr(MemberExprClass, T, VK, OK, Base->isTypeDependent(),
             Base->isValueDependent(), Base->isInstantiationDependent(),
             Base->containsUnexpandedParameterPack()),
        Base(Base), MemberDecl(MemberDecl), MemberDNLoc(NameInfo.getInfo()),
        MemberLoc(NameInfo.getLoc()) {
    assert(!NameInfo.getName() ||
           MemberDecl->getDeclName() == NameInfo.getName());
    MemberExprBits.IsArrow = IsArrow;
    MemberExprBits.HasQualifierOrFoundDecl = false;
    MemberExprBits.HasTemplateKWAndArgsInfo = false;
    MemberExprBits.HadMultipleCandidates = false;
    MemberExprBits.NonOdrUseReason = NOUR;
    MemberExprBits.OperatorLoc = OperatorLoc;
  }
  
  MemberExpr *MemberExpr::Create(
      const ASTContext &C, Expr *Base, bool IsArrow, SourceLocation OperatorLoc,
      NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
      ValueDecl *MemberDecl, DeclAccessPair FoundDecl,
      DeclarationNameInfo NameInfo, const TemplateArgumentListInfo *TemplateArgs,
      QualType T, ExprValueKind VK, ExprObjectKind OK, NonOdrUseReason NOUR) {
    bool HasQualOrFound = QualifierLoc || FoundDecl.getDecl() != MemberDecl ||
                          FoundDecl.getAccess() != MemberDecl->getAccess();
    bool HasTemplateKWAndArgsInfo = TemplateArgs || TemplateKWLoc.isValid();
    std::size_t Size =
        totalSizeToAlloc<MemberExprNameQualifier, ASTTemplateKWAndArgsInfo,
                         TemplateArgumentLoc>(
            HasQualOrFound ? 1 : 0, HasTemplateKWAndArgsInfo ? 1 : 0,
            TemplateArgs ? TemplateArgs->size() : 0);
  
    void *Mem = C.Allocate(Size, alignof(MemberExpr));
    MemberExpr *E = new (Mem) MemberExpr(Base, IsArrow, OperatorLoc, MemberDecl,
                                         NameInfo, T, VK, OK, NOUR);
  
    if (HasQualOrFound) {
      // FIXME: Wrong. We should be looking at the member declaration we found.
      if (QualifierLoc && QualifierLoc.getNestedNameSpecifier()->isDependent()) {
        E->setValueDependent(true);
        E->setTypeDependent(true);
        E->setInstantiationDependent(true);
      }
      else if (QualifierLoc &&
               QualifierLoc.getNestedNameSpecifier()->isInstantiationDependent())
        E->setInstantiationDependent(true);
  
      E->MemberExprBits.HasQualifierOrFoundDecl = true;
  
      MemberExprNameQualifier *NQ =
          E->getTrailingObjects<MemberExprNameQualifier>();
      NQ->QualifierLoc = QualifierLoc;
      NQ->FoundDecl = FoundDecl;
    }
  
    E->MemberExprBits.HasTemplateKWAndArgsInfo =
        TemplateArgs || TemplateKWLoc.isValid();
  
    if (TemplateArgs) {
      bool Dependent = false;
      bool InstantiationDependent = false;
      bool ContainsUnexpandedParameterPack = false;
      E->getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
          TemplateKWLoc, *TemplateArgs,
          E->getTrailingObjects<TemplateArgumentLoc>(), Dependent,
          InstantiationDependent, ContainsUnexpandedParameterPack);
      if (InstantiationDependent)
        E->setInstantiationDependent(true);
    } else if (TemplateKWLoc.isValid()) {
      E->getTrailingObjects<ASTTemplateKWAndArgsInfo>()->initializeFrom(
          TemplateKWLoc);
    }
  
    return E;
  }
  
  MemberExpr *MemberExpr::CreateEmpty(const ASTContext &Context,
                                      bool HasQualifier, bool HasFoundDecl,
                                      bool HasTemplateKWAndArgsInfo,
                                      unsigned NumTemplateArgs) {
    assert((!NumTemplateArgs || HasTemplateKWAndArgsInfo) &&
           "template args but no template arg info?");
    bool HasQualOrFound = HasQualifier || HasFoundDecl;
    std::size_t Size =
        totalSizeToAlloc<MemberExprNameQualifier, ASTTemplateKWAndArgsInfo,
                         TemplateArgumentLoc>(HasQualOrFound ? 1 : 0,
                                              HasTemplateKWAndArgsInfo ? 1 : 0,
                                              NumTemplateArgs);
    void *Mem = Context.Allocate(Size, alignof(MemberExpr));
    return new (Mem) MemberExpr(EmptyShell());
  }
  
  SourceLocation MemberExpr::getBeginLoc() const {
    if (isImplicitAccess()) {
      if (hasQualifier())
        return getQualifierLoc().getBeginLoc();
      return MemberLoc;
    }
  
    // FIXME: We don't want this to happen. Rather, we should be able to
    // detect all kinds of implicit accesses more cleanly.
    SourceLocation BaseStartLoc = getBase()->getBeginLoc();
    if (BaseStartLoc.isValid())
      return BaseStartLoc;
    return MemberLoc;
  }
  SourceLocation MemberExpr::getEndLoc() const {
    SourceLocation EndLoc = getMemberNameInfo().getEndLoc();
    if (hasExplicitTemplateArgs())
      EndLoc = getRAngleLoc();
    else if (EndLoc.isInvalid())
      EndLoc = getBase()->getEndLoc();
    return EndLoc;
  }
  
  bool CastExpr::CastConsistency() const {
    switch (getCastKind()) {
    case CK_DerivedToBase:
    case CK_UncheckedDerivedToBase:
    case CK_DerivedToBaseMemberPointer:
    case CK_BaseToDerived:
    case CK_BaseToDerivedMemberPointer:
      assert(!path_empty() && "Cast kind should have a base path!");
      break;
  
    case CK_CPointerToObjCPointerCast:
      assert(getType()->isObjCObjectPointerType());
      assert(getSubExpr()->getType()->isPointerType());
      goto CheckNoBasePath;
  
    case CK_BlockPointerToObjCPointerCast:
      assert(getType()->isObjCObjectPointerType());
      assert(getSubExpr()->getType()->isBlockPointerType());
      goto CheckNoBasePath;
  
    case CK_ReinterpretMemberPointer:
      assert(getType()->isMemberPointerType());
      assert(getSubExpr()->getType()->isMemberPointerType());
      goto CheckNoBasePath;
  
    case CK_BitCast:
      // Arbitrary casts to C pointer types count as bitcasts.
      // Otherwise, we should only have block and ObjC pointer casts
      // here if they stay within the type kind.
      if (!getType()->isPointerType()) {
        assert(getType()->isObjCObjectPointerType() ==
               getSubExpr()->getType()->isObjCObjectPointerType());
        assert(getType()->isBlockPointerType() ==
               getSubExpr()->getType()->isBlockPointerType());
      }
      goto CheckNoBasePath;
  
    case CK_AnyPointerToBlockPointerCast:
      assert(getType()->isBlockPointerType());
      assert(getSubExpr()->getType()->isAnyPointerType() &&
             !getSubExpr()->getType()->isBlockPointerType());
      goto CheckNoBasePath;
  
    case CK_CopyAndAutoreleaseBlockObject:
      assert(getType()->isBlockPointerType());
      assert(getSubExpr()->getType()->isBlockPointerType());
      goto CheckNoBasePath;
  
    case CK_FunctionToPointerDecay:
      assert(getType()->isPointerType());
      assert(getSubExpr()->getType()->isFunctionType());
      goto CheckNoBasePath;
  
    case CK_AddressSpaceConversion: {
      auto Ty = getType();
      auto SETy = getSubExpr()->getType();
      assert(getValueKindForType(Ty) == Expr::getValueKindForType(SETy));
      if (/*isRValue()*/ !Ty->getPointeeType().isNull()) {
        Ty = Ty->getPointeeType();
        SETy = SETy->getPointeeType();
      }
      assert(!Ty.isNull() && !SETy.isNull() &&
             Ty.getAddressSpace() != SETy.getAddressSpace());
      goto CheckNoBasePath;
    }
    // These should not have an inheritance path.
    case CK_Dynamic:
    case CK_ToUnion:
    case CK_ArrayToPointerDecay:
    case CK_NullToMemberPointer:
    case CK_NullToPointer:
    case CK_ConstructorConversion:
    case CK_IntegralToPointer:
    case CK_PointerToIntegral:
    case CK_ToVoid:
    case CK_VectorSplat:
    case CK_IntegralCast:
    case CK_BooleanToSignedIntegral:
    case CK_IntegralToFloating:
    case CK_FloatingToIntegral:
    case CK_FloatingCast:
    case CK_ObjCObjectLValueCast:
    case CK_FloatingRealToComplex:
    case CK_FloatingComplexToReal:
    case CK_FloatingComplexCast:
    case CK_FloatingComplexToIntegralComplex:
    case CK_IntegralRealToComplex:
    case CK_IntegralComplexToReal:
    case CK_IntegralComplexCast:
    case CK_IntegralComplexToFloatingComplex:
    case CK_ARCProduceObject:
    case CK_ARCConsumeObject:
    case CK_ARCReclaimReturnedObject:
    case CK_ARCExtendBlockObject:
    case CK_ZeroToOCLOpaqueType:
    case CK_IntToOCLSampler:
    case CK_FixedPointCast:
    case CK_FixedPointToIntegral:
    case CK_IntegralToFixedPoint:
      assert(!getType()->isBooleanType() && "unheralded conversion to bool");
      goto CheckNoBasePath;
  
    case CK_Dependent:
    case CK_LValueToRValue:
    case CK_NoOp:
    case CK_AtomicToNonAtomic:
    case CK_NonAtomicToAtomic:
    case CK_PointerToBoolean:
    case CK_IntegralToBoolean:
    case CK_FloatingToBoolean:
    case CK_MemberPointerToBoolean:
    case CK_FloatingComplexToBoolean:
    case CK_IntegralComplexToBoolean:
    case CK_LValueBitCast:            // -> bool&
    case CK_LValueToRValueBitCast:
    case CK_UserDefinedConversion:    // operator bool()
    case CK_BuiltinFnToFnPtr:
    case CK_FixedPointToBoolean:
    CheckNoBasePath:
      assert(path_empty() && "Cast kind should not have a base path!");
      break;
    }
    return true;
  }
  
  const char *CastExpr::getCastKindName(CastKind CK) {
    switch (CK) {
  #define CAST_OPERATION(Name) case CK_##Name: return #Name;
  #include "clang/AST/OperationKinds.def"
    }
    llvm_unreachable("Unhandled cast kind!");
  }
  
  namespace {
    const Expr *skipImplicitTemporary(const Expr *E) {
      // Skip through reference binding to temporary.
      if (auto *Materialize = dyn_cast<MaterializeTemporaryExpr>(E))
        E = Materialize->GetTemporaryExpr();
  
      // Skip any temporary bindings; they're implicit.
      if (auto *Binder = dyn_cast<CXXBindTemporaryExpr>(E))
        E = Binder->getSubExpr();
  
      return E;
    }
  }
  
  Expr *CastExpr::getSubExprAsWritten() {
    const Expr *SubExpr = nullptr;
    const CastExpr *E = this;
    do {
      SubExpr = skipImplicitTemporary(E->getSubExpr());
  
      // Conversions by constructor and conversion functions have a
      // subexpression describing the call; strip it off.
      if (E->getCastKind() == CK_ConstructorConversion)
        SubExpr =
          skipImplicitTemporary(cast<CXXConstructExpr>(SubExpr)->getArg(0));
      else if (E->getCastKind() == CK_UserDefinedConversion) {
        assert((isa<CXXMemberCallExpr>(SubExpr) ||
                isa<BlockExpr>(SubExpr)) &&
               "Unexpected SubExpr for CK_UserDefinedConversion.");
        if (auto *MCE = dyn_cast<CXXMemberCallExpr>(SubExpr))
          SubExpr = MCE->getImplicitObjectArgument();
      }
  
      // If the subexpression we're left with is an implicit cast, look
      // through that, too.
    } while ((E = dyn_cast<ImplicitCastExpr>(SubExpr)));
  
    return const_cast<Expr*>(SubExpr);
  }
  
  NamedDecl *CastExpr::getConversionFunction() const {
    const Expr *SubExpr = nullptr;
  
    for (const CastExpr *E = this; E; E = dyn_cast<ImplicitCastExpr>(SubExpr)) {
      SubExpr = skipImplicitTemporary(E->getSubExpr());
  
      if (E->getCastKind() == CK_ConstructorConversion)
        return cast<CXXConstructExpr>(SubExpr)->getConstructor();
  
      if (E->getCastKind() == CK_UserDefinedConversion) {
        if (auto *MCE = dyn_cast<CXXMemberCallExpr>(SubExpr))
          return MCE->getMethodDecl();
      }
    }
  
    return nullptr;
  }
  
  CXXBaseSpecifier **CastExpr::path_buffer() {
    switch (getStmtClass()) {
  #define ABSTRACT_STMT(x)
  #define CASTEXPR(Type, Base)                                                   \
    case Stmt::Type##Class:                                                      \
      return static_cast<Type *>(this)->getTrailingObjects<CXXBaseSpecifier *>();
  #define STMT(Type, Base)
  #include "clang/AST/StmtNodes.inc"
    default:
      llvm_unreachable("non-cast expressions not possible here");
    }
  }
  
  const FieldDecl *CastExpr::getTargetFieldForToUnionCast(QualType unionType,
                                                          QualType opType) {
    auto RD = unionType->castAs<RecordType>()->getDecl();
    return getTargetFieldForToUnionCast(RD, opType);
  }
  
  const FieldDecl *CastExpr::getTargetFieldForToUnionCast(const RecordDecl *RD,
                                                          QualType OpType) {
    auto &Ctx = RD->getASTContext();
    RecordDecl::field_iterator Field, FieldEnd;
    for (Field = RD->field_begin(), FieldEnd = RD->field_end();
         Field != FieldEnd; ++Field) {
      if (Ctx.hasSameUnqualifiedType(Field->getType(), OpType) &&
          !Field->isUnnamedBitfield()) {
        return *Field;
      }
    }
    return nullptr;
  }
  
  ImplicitCastExpr *ImplicitCastExpr::Create(const ASTContext &C, QualType T,
                                             CastKind Kind, Expr *Operand,
                                             const CXXCastPath *BasePath,
                                             ExprValueKind VK) {
    unsigned PathSize = (BasePath ? BasePath->size() : 0);
    void *Buffer = C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *>(PathSize));
    // Per C++ [conv.lval]p3, lvalue-to-rvalue conversions on class and
    // std::nullptr_t have special semantics not captured by CK_LValueToRValue.
    assert((Kind != CK_LValueToRValue ||
            !(T->isNullPtrType() || T->getAsCXXRecordDecl())) &&
           "invalid type for lvalue-to-rvalue conversion");
    ImplicitCastExpr *E =
      new (Buffer) ImplicitCastExpr(T, Kind, Operand, PathSize, VK);
    if (PathSize)
      std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                                E->getTrailingObjects<CXXBaseSpecifier *>());
    return E;
  }
  
  ImplicitCastExpr *ImplicitCastExpr::CreateEmpty(const ASTContext &C,
                                                  unsigned PathSize) {
    void *Buffer = C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *>(PathSize));
    return new (Buffer) ImplicitCastExpr(EmptyShell(), PathSize);
  }
  
  
  CStyleCastExpr *CStyleCastExpr::Create(const ASTContext &C, QualType T,
                                         ExprValueKind VK, CastKind K, Expr *Op,
                                         const CXXCastPath *BasePath,
                                         TypeSourceInfo *WrittenTy,
                                         SourceLocation L, SourceLocation R) {
    unsigned PathSize = (BasePath ? BasePath->size() : 0);
    void *Buffer = C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *>(PathSize));
    CStyleCastExpr *E =
      new (Buffer) CStyleCastExpr(T, VK, K, Op, PathSize, WrittenTy, L, R);
    if (PathSize)
      std::uninitialized_copy_n(BasePath->data(), BasePath->size(),
                                E->getTrailingObjects<CXXBaseSpecifier *>());
    return E;
  }
  
  CStyleCastExpr *CStyleCastExpr::CreateEmpty(const ASTContext &C,
                                              unsigned PathSize) {
    void *Buffer = C.Allocate(totalSizeToAlloc<CXXBaseSpecifier *>(PathSize));
    return new (Buffer) CStyleCastExpr(EmptyShell(), PathSize);
  }
  
  /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
  /// corresponds to, e.g. "<<=".
  StringRef BinaryOperator::getOpcodeStr(Opcode Op) {
    switch (Op) {
  #define BINARY_OPERATION(Name, Spelling) case BO_##Name: return Spelling;
  #include "clang/AST/OperationKinds.def"
    }
    llvm_unreachable("Invalid OpCode!");
  }
  
  BinaryOperatorKind
  BinaryOperator::getOverloadedOpcode(OverloadedOperatorKind OO) {
    switch (OO) {
    default: llvm_unreachable("Not an overloadable binary operator");
    case OO_Plus: return BO_Add;
    case OO_Minus: return BO_Sub;
    case OO_Star: return BO_Mul;
    case OO_Slash: return BO_Div;
    case OO_Percent: return BO_Rem;
    case OO_Caret: return BO_Xor;
    case OO_Amp: return BO_And;
    case OO_Pipe: return BO_Or;
    case OO_Equal: return BO_Assign;
    case OO_Spaceship: return BO_Cmp;
    case OO_Less: return BO_LT;
    case OO_Greater: return BO_GT;
    case OO_PlusEqual: return BO_AddAssign;
    case OO_MinusEqual: return BO_SubAssign;
    case OO_StarEqual: return BO_MulAssign;
    case OO_SlashEqual: return BO_DivAssign;
    case OO_PercentEqual: return BO_RemAssign;
    case OO_CaretEqual: return BO_XorAssign;
    case OO_AmpEqual: return BO_AndAssign;
    case OO_PipeEqual: return BO_OrAssign;
    case OO_LessLess: return BO_Shl;
    case OO_GreaterGreater: return BO_Shr;
    case OO_LessLessEqual: return BO_ShlAssign;
    case OO_GreaterGreaterEqual: return BO_ShrAssign;
    case OO_EqualEqual: return BO_EQ;
    case OO_ExclaimEqual: return BO_NE;
    case OO_LessEqual: return BO_LE;
    case OO_GreaterEqual: return BO_GE;
    case OO_AmpAmp: return BO_LAnd;
    case OO_PipePipe: return BO_LOr;
    case OO_Comma: return BO_Comma;
    case OO_ArrowStar: return BO_PtrMemI;
    }
  }
  
  OverloadedOperatorKind BinaryOperator::getOverloadedOperator(Opcode Opc) {
    static const OverloadedOperatorKind OverOps[] = {
      /* .* Cannot be overloaded */OO_None, OO_ArrowStar,
      OO_Star, OO_Slash, OO_Percent,
      OO_Plus, OO_Minus,
      OO_LessLess, OO_GreaterGreater,
      OO_Spaceship,
      OO_Less, OO_Greater, OO_LessEqual, OO_GreaterEqual,
      OO_EqualEqual, OO_ExclaimEqual,
      OO_Amp,
      OO_Caret,
      OO_Pipe,
      OO_AmpAmp,
      OO_PipePipe,
      OO_Equal, OO_StarEqual,
      OO_SlashEqual, OO_PercentEqual,
      OO_PlusEqual, OO_MinusEqual,
      OO_LessLessEqual, OO_GreaterGreaterEqual,
      OO_AmpEqual, OO_CaretEqual,
      OO_PipeEqual,
      OO_Comma
    };
    return OverOps[Opc];
  }
  
  bool BinaryOperator::isNullPointerArithmeticExtension(ASTContext &Ctx,
                                                        Opcode Opc,
                                                        Expr *LHS, Expr *RHS) {
    if (Opc != BO_Add)
      return false;
  
    // Check that we have one pointer and one integer operand.
    Expr *PExp;
    if (LHS->getType()->isPointerType()) {
      if (!RHS->getType()->isIntegerType())
        return false;
      PExp = LHS;
    } else if (RHS->getType()->isPointerType()) {
      if (!LHS->getType()->isIntegerType())
        return false;
      PExp = RHS;
    } else {
      return false;
    }
  
    // Check that the pointer is a nullptr.
    if (!PExp->IgnoreParenCasts()
            ->isNullPointerConstant(Ctx, Expr::NPC_ValueDependentIsNotNull))
      return false;
  
    // Check that the pointee type is char-sized.
    const PointerType *PTy = PExp->getType()->getAs<PointerType>();
    if (!PTy || !PTy->getPointeeType()->isCharType())
      return false;
  
    return true;
  }
  
  static QualType getDecayedSourceLocExprType(const ASTContext &Ctx,
                                              SourceLocExpr::IdentKind Kind) {
    switch (Kind) {
    case SourceLocExpr::File:
    case SourceLocExpr::Function: {
      QualType ArrTy = Ctx.getStringLiteralArrayType(Ctx.CharTy, 0);
      return Ctx.getPointerType(ArrTy->getAsArrayTypeUnsafe()->getElementType());
    }
    case SourceLocExpr::Line:
    case SourceLocExpr::Column:
      return Ctx.UnsignedIntTy;
    }
    llvm_unreachable("unhandled case");
  }
  
  SourceLocExpr::SourceLocExpr(const ASTContext &Ctx, IdentKind Kind,
                               SourceLocation BLoc, SourceLocation RParenLoc,
                               DeclContext *ParentContext)
      : Expr(SourceLocExprClass, getDecayedSourceLocExprType(Ctx, Kind),
             VK_RValue, OK_Ordinary, false, false, false, false),
        BuiltinLoc(BLoc), RParenLoc(RParenLoc), ParentContext(ParentContext) {
    SourceLocExprBits.Kind = Kind;
  }
  
  StringRef SourceLocExpr::getBuiltinStr() const {
    switch (getIdentKind()) {
    case File:
      return "__builtin_FILE";
    case Function:
      return "__builtin_FUNCTION";
    case Line:
      return "__builtin_LINE";
    case Column:
      return "__builtin_COLUMN";
    }
    llvm_unreachable("unexpected IdentKind!");
  }
  
  APValue SourceLocExpr::EvaluateInContext(const ASTContext &Ctx,
                                           const Expr *DefaultExpr) const {
    SourceLocation Loc;
    const DeclContext *Context;
  
    std::tie(Loc,
             Context) = [&]() -> std::pair<SourceLocation, const DeclContext *> {
      if (auto *DIE = dyn_cast_or_null<CXXDefaultInitExpr>(DefaultExpr))
        return {DIE->getUsedLocation(), DIE->getUsedContext()};
      if (auto *DAE = dyn_cast_or_null<CXXDefaultArgExpr>(DefaultExpr))
        return {DAE->getUsedLocation(), DAE->getUsedContext()};
      return {this->getLocation(), this->getParentContext()};
    }();
  
    PresumedLoc PLoc = Ctx.getSourceManager().getPresumedLoc(
        Ctx.getSourceManager().getExpansionRange(Loc).getEnd());
  
    auto MakeStringLiteral = [&](StringRef Tmp) {
      using LValuePathEntry = APValue::LValuePathEntry;
      StringLiteral *Res = Ctx.getPredefinedStringLiteralFromCache(Tmp);
      // Decay the string to a pointer to the first character.
      LValuePathEntry Path[1] = {LValuePathEntry::ArrayIndex(0)};
      return APValue(Res, CharUnits::Zero(), Path, /*OnePastTheEnd=*/false);
    };
  
    switch (getIdentKind()) {
    case SourceLocExpr::File:
      return MakeStringLiteral(PLoc.getFilename());
    case SourceLocExpr::Function: {
      const Decl *CurDecl = dyn_cast_or_null<Decl>(Context);
      return MakeStringLiteral(
          CurDecl ? PredefinedExpr::ComputeName(PredefinedExpr::Function, CurDecl)
                  : std::string(""));
    }
    case SourceLocExpr::Line:
    case SourceLocExpr::Column: {
      llvm::APSInt IntVal(Ctx.getIntWidth(Ctx.UnsignedIntTy),
                          /*isUnsigned=*/true);
      IntVal = getIdentKind() == SourceLocExpr::Line ? PLoc.getLine()
                                                     : PLoc.getColumn();
      return APValue(IntVal);
    }
    }
    llvm_unreachable("unhandled case");
  }
  
  InitListExpr::InitListExpr(const ASTContext &C, SourceLocation lbraceloc,
                             ArrayRef<Expr*> initExprs, SourceLocation rbraceloc)
    : Expr(InitListExprClass, QualType(), VK_RValue, OK_Ordinary, false, false,
           false, false),
      InitExprs(C, initExprs.size()),
      LBraceLoc(lbraceloc), RBraceLoc(rbraceloc), AltForm(nullptr, true)
  {
    sawArrayRangeDesignator(false);
    for (unsigned I = 0; I != initExprs.size(); ++I) {
      if (initExprs[I]->isTypeDependent())
        ExprBits.TypeDependent = true;
      if (initExprs[I]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (initExprs[I]->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (initExprs[I]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
    }
  
    InitExprs.insert(C, InitExprs.end(), initExprs.begin(), initExprs.end());
  }
  
  void InitListExpr::reserveInits(const ASTContext &C, unsigned NumInits) {
    if (NumInits > InitExprs.size())
      InitExprs.reserve(C, NumInits);
  }
  
  void InitListExpr::resizeInits(const ASTContext &C, unsigned NumInits) {
    InitExprs.resize(C, NumInits, nullptr);
  }
  
  Expr *InitListExpr::updateInit(const ASTContext &C, unsigned Init, Expr *expr) {
    if (Init >= InitExprs.size()) {
      InitExprs.insert(C, InitExprs.end(), Init - InitExprs.size() + 1, nullptr);
      setInit(Init, expr);
      return nullptr;
    }
  
    Expr *Result = cast_or_null<Expr>(InitExprs[Init]);
    setInit(Init, expr);
    return Result;
  }
  
  void InitListExpr::setArrayFiller(Expr *filler) {
    assert(!hasArrayFiller() && "Filler already set!");
    ArrayFillerOrUnionFieldInit = filler;
    // Fill out any "holes" in the array due to designated initializers.
    Expr **inits = getInits();
    for (unsigned i = 0, e = getNumInits(); i != e; ++i)
      if (inits[i] == nullptr)
        inits[i] = filler;
  }
  
  bool InitListExpr::isStringLiteralInit() const {
    if (getNumInits() != 1)
      return false;
    const ArrayType *AT = getType()->getAsArrayTypeUnsafe();
    if (!AT || !AT->getElementType()->isIntegerType())
      return false;
    // It is possible for getInit() to return null.
    const Expr *Init = getInit(0);
    if (!Init)
      return false;
    Init = Init->IgnoreParens();
    return isa<StringLiteral>(Init) || isa<ObjCEncodeExpr>(Init);
  }
  
  bool InitListExpr::isTransparent() const {
    assert(isSemanticForm() && "syntactic form never semantically transparent");
  
    // A glvalue InitListExpr is always just sugar.
    if (isGLValue()) {
      assert(getNumInits() == 1 && "multiple inits in glvalue init list");
      return true;
    }
  
    // Otherwise, we're sugar if and only if we have exactly one initializer that
    // is of the same type.
    if (getNumInits() != 1 || !getInit(0))
      return false;
  
    // Don't confuse aggregate initialization of a struct X { X &x; }; with a
    // transparent struct copy.
    if (!getInit(0)->isRValue() && getType()->isRecordType())
      return false;
  
    return getType().getCanonicalType() ==
           getInit(0)->getType().getCanonicalType();
  }
  
  bool InitListExpr::isIdiomaticZeroInitializer(const LangOptions &LangOpts) const {
    assert(isSyntacticForm() && "only test syntactic form as zero initializer");
  
    if (LangOpts.CPlusPlus || getNumInits() != 1 || !getInit(0)) {
      return false;
    }
  
    const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(getInit(0)->IgnoreImplicit());
    return Lit && Lit->getValue() == 0;
  }
  
  SourceLocation InitListExpr::getBeginLoc() const {
    if (InitListExpr *SyntacticForm = getSyntacticForm())
      return SyntacticForm->getBeginLoc();
    SourceLocation Beg = LBraceLoc;
    if (Beg.isInvalid()) {
      // Find the first non-null initializer.
      for (InitExprsTy::const_iterator I = InitExprs.begin(),
                                       E = InitExprs.end();
        I != E; ++I) {
        if (Stmt *S = *I) {
          Beg = S->getBeginLoc();
          break;
        }
      }
    }
    return Beg;
  }
  
  SourceLocation InitListExpr::getEndLoc() const {
    if (InitListExpr *SyntacticForm = getSyntacticForm())
      return SyntacticForm->getEndLoc();
    SourceLocation End = RBraceLoc;
    if (End.isInvalid()) {
      // Find the first non-null initializer from the end.
      for (InitExprsTy::const_reverse_iterator I = InitExprs.rbegin(),
           E = InitExprs.rend();
           I != E; ++I) {
        if (Stmt *S = *I) {
          End = S->getEndLoc();
          break;
        }
      }
    }
    return End;
  }
  
  /// getFunctionType - Return the underlying function type for this block.
  ///
  const FunctionProtoType *BlockExpr::getFunctionType() const {
    // The block pointer is never sugared, but the function type might be.
    return cast<BlockPointerType>(getType())
             ->getPointeeType()->castAs<FunctionProtoType>();
  }
  
  SourceLocation BlockExpr::getCaretLocation() const {
    return TheBlock->getCaretLocation();
  }
  const Stmt *BlockExpr::getBody() const {
    return TheBlock->getBody();
  }
  Stmt *BlockExpr::getBody() {
    return TheBlock->getBody();
  }
  
  
  //===----------------------------------------------------------------------===//
  // Generic Expression Routines
  //===----------------------------------------------------------------------===//
  
  /// isUnusedResultAWarning - Return true if this immediate expression should
  /// be warned about if the result is unused.  If so, fill in Loc and Ranges
  /// with location to warn on and the source range[s] to report with the
  /// warning.
  bool Expr::isUnusedResultAWarning(const Expr *&WarnE, SourceLocation &Loc,
                                    SourceRange &R1, SourceRange &R2,
                                    ASTContext &Ctx) const {
    // Don't warn if the expr is type dependent. The type could end up
    // instantiating to void.
    if (isTypeDependent())
      return false;
  
    switch (getStmtClass()) {
    default:
      if (getType()->isVoidType())
        return false;
      WarnE = this;
      Loc = getExprLoc();
      R1 = getSourceRange();
      return true;
    case ParenExprClass:
      return cast<ParenExpr>(this)->getSubExpr()->
        isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case GenericSelectionExprClass:
      return cast<GenericSelectionExpr>(this)->getResultExpr()->
        isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case CoawaitExprClass:
    case CoyieldExprClass:
      return cast<CoroutineSuspendExpr>(this)->getResumeExpr()->
        isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case ChooseExprClass:
      return cast<ChooseExpr>(this)->getChosenSubExpr()->
        isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case UnaryOperatorClass: {
      const UnaryOperator *UO = cast<UnaryOperator>(this);
  
      switch (UO->getOpcode()) {
      case UO_Plus:
      case UO_Minus:
      case UO_AddrOf:
      case UO_Not:
      case UO_LNot:
      case UO_Deref:
        break;
      case UO_Coawait:
        // This is just the 'operator co_await' call inside the guts of a
        // dependent co_await call.
      case UO_PostInc:
      case UO_PostDec:
      case UO_PreInc:
      case UO_PreDec:                 // ++/--
        return false;  // Not a warning.
      case UO_Real:
      case UO_Imag:
        // accessing a piece of a volatile complex is a side-effect.
        if (Ctx.getCanonicalType(UO->getSubExpr()->getType())
            .isVolatileQualified())
          return false;
        break;
      case UO_Extension:
        return UO->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
      }
      WarnE = this;
      Loc = UO->getOperatorLoc();
      R1 = UO->getSubExpr()->getSourceRange();
      return true;
    }
    case BinaryOperatorClass: {
      const BinaryOperator *BO = cast<BinaryOperator>(this);
      switch (BO->getOpcode()) {
        default:
          break;
        // Consider the RHS of comma for side effects. LHS was checked by
        // Sema::CheckCommaOperands.
        case BO_Comma:
          // ((foo = <blah>), 0) is an idiom for hiding the result (and
          // lvalue-ness) of an assignment written in a macro.
          if (IntegerLiteral *IE =
                dyn_cast<IntegerLiteral>(BO->getRHS()->IgnoreParens()))
            if (IE->getValue() == 0)
              return false;
          return BO->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
        // Consider '||', '&&' to have side effects if the LHS or RHS does.
        case BO_LAnd:
        case BO_LOr:
          if (!BO->getLHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx) ||
              !BO->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx))
            return false;
          break;
      }
      if (BO->isAssignmentOp())
        return false;
      WarnE = this;
      Loc = BO->getOperatorLoc();
      R1 = BO->getLHS()->getSourceRange();
      R2 = BO->getRHS()->getSourceRange();
      return true;
    }
    case CompoundAssignOperatorClass:
    case VAArgExprClass:
    case AtomicExprClass:
      return false;
  
    case ConditionalOperatorClass: {
      // If only one of the LHS or RHS is a warning, the operator might
      // be being used for control flow. Only warn if both the LHS and
      // RHS are warnings.
      const auto *Exp = cast<ConditionalOperator>(this);
      return Exp->getLHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx) &&
             Exp->getRHS()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }
    case BinaryConditionalOperatorClass: {
      const auto *Exp = cast<BinaryConditionalOperator>(this);
      return Exp->getFalseExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }
  
    case MemberExprClass:
      WarnE = this;
      Loc = cast<MemberExpr>(this)->getMemberLoc();
      R1 = SourceRange(Loc, Loc);
      R2 = cast<MemberExpr>(this)->getBase()->getSourceRange();
      return true;
  
    case ArraySubscriptExprClass:
      WarnE = this;
      Loc = cast<ArraySubscriptExpr>(this)->getRBracketLoc();
      R1 = cast<ArraySubscriptExpr>(this)->getLHS()->getSourceRange();
      R2 = cast<ArraySubscriptExpr>(this)->getRHS()->getSourceRange();
      return true;
  
    case CXXOperatorCallExprClass: {
      // Warn about operator ==,!=,<,>,<=, and >= even when user-defined operator
      // overloads as there is no reasonable way to define these such that they
      // have non-trivial, desirable side-effects. See the -Wunused-comparison
      // warning: operators == and != are commonly typo'ed, and so warning on them
      // provides additional value as well. If this list is updated,
      // DiagnoseUnusedComparison should be as well.
      const CXXOperatorCallExpr *Op = cast<CXXOperatorCallExpr>(this);
      switch (Op->getOperator()) {
      default:
        break;
      case OO_EqualEqual:
      case OO_ExclaimEqual:
      case OO_Less:
      case OO_Greater:
      case OO_GreaterEqual:
      case OO_LessEqual:
        if (Op->getCallReturnType(Ctx)->isReferenceType() ||
            Op->getCallReturnType(Ctx)->isVoidType())
          break;
        WarnE = this;
        Loc = Op->getOperatorLoc();
        R1 = Op->getSourceRange();
        return true;
      }
  
      // Fallthrough for generic call handling.
      LLVM_FALLTHROUGH;
    }
    case CallExprClass:
    case CXXMemberCallExprClass:
    case UserDefinedLiteralClass: {
      // If this is a direct call, get the callee.
      const CallExpr *CE = cast<CallExpr>(this);
      if (const Decl *FD = CE->getCalleeDecl()) {
        // If the callee has attribute pure, const, or warn_unused_result, warn
        // about it. void foo() { strlen("bar"); } should warn.
        //
        // Note: If new cases are added here, DiagnoseUnusedExprResult should be
        // updated to match for QoI.
        if (CE->hasUnusedResultAttr(Ctx) ||
            FD->hasAttr<PureAttr>() || FD->hasAttr<ConstAttr>()) {
          WarnE = this;
          Loc = CE->getCallee()->getBeginLoc();
          R1 = CE->getCallee()->getSourceRange();
  
          if (unsigned NumArgs = CE->getNumArgs())
            R2 = SourceRange(CE->getArg(0)->getBeginLoc(),
                             CE->getArg(NumArgs - 1)->getEndLoc());
          return true;
        }
      }
      return false;
    }
  
    // If we don't know precisely what we're looking at, let's not warn.
    case UnresolvedLookupExprClass:
    case CXXUnresolvedConstructExprClass:
      return false;
  
    case CXXTemporaryObjectExprClass:
    case CXXConstructExprClass: {
      if (const CXXRecordDecl *Type = getType()->getAsCXXRecordDecl()) {
        const auto *WarnURAttr = Type->getAttr<WarnUnusedResultAttr>();
        if (Type->hasAttr<WarnUnusedAttr>() ||
            (WarnURAttr && WarnURAttr->IsCXX11NoDiscard())) {
          WarnE = this;
          Loc = getBeginLoc();
          R1 = getSourceRange();
          return true;
        }
      }
  
      const auto *CE = cast<CXXConstructExpr>(this);
      if (const CXXConstructorDecl *Ctor = CE->getConstructor()) {
        const auto *WarnURAttr = Ctor->getAttr<WarnUnusedResultAttr>();
        if (WarnURAttr && WarnURAttr->IsCXX11NoDiscard()) {
          WarnE = this;
          Loc = getBeginLoc();
          R1 = getSourceRange();
  
          if (unsigned NumArgs = CE->getNumArgs())
            R2 = SourceRange(CE->getArg(0)->getBeginLoc(),
                             CE->getArg(NumArgs - 1)->getEndLoc());
          return true;
        }
      }
  
      return false;
    }
  
    case ObjCMessageExprClass: {
      const ObjCMessageExpr *ME = cast<ObjCMessageExpr>(this);
      if (Ctx.getLangOpts().ObjCAutoRefCount &&
          ME->isInstanceMessage() &&
          !ME->getType()->isVoidType() &&
          ME->getMethodFamily() == OMF_init) {
        WarnE = this;
        Loc = getExprLoc();
        R1 = ME->getSourceRange();
        return true;
      }
  
      if (const ObjCMethodDecl *MD = ME->getMethodDecl())
        if (MD->hasAttr<WarnUnusedResultAttr>()) {
          WarnE = this;
          Loc = getExprLoc();
          return true;
        }
  
      return false;
    }
  
    case ObjCPropertyRefExprClass:
      WarnE = this;
      Loc = getExprLoc();
      R1 = getSourceRange();
      return true;
  
    case PseudoObjectExprClass: {
      const PseudoObjectExpr *PO = cast<PseudoObjectExpr>(this);
  
      // Only complain about things that have the form of a getter.
      if (isa<UnaryOperator>(PO->getSyntacticForm()) ||
          isa<BinaryOperator>(PO->getSyntacticForm()))
        return false;
  
      WarnE = this;
      Loc = getExprLoc();
      R1 = getSourceRange();
      return true;
    }
  
    case StmtExprClass: {
      // Statement exprs don't logically have side effects themselves, but are
      // sometimes used in macros in ways that give them a type that is unused.
      // For example ({ blah; foo(); }) will end up with a type if foo has a type.
      // however, if the result of the stmt expr is dead, we don't want to emit a
      // warning.
      const CompoundStmt *CS = cast<StmtExpr>(this)->getSubStmt();
      if (!CS->body_empty()) {
        if (const Expr *E = dyn_cast<Expr>(CS->body_back()))
          return E->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
        if (const LabelStmt *Label = dyn_cast<LabelStmt>(CS->body_back()))
          if (const Expr *E = dyn_cast<Expr>(Label->getSubStmt()))
            return E->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
      }
  
      if (getType()->isVoidType())
        return false;
      WarnE = this;
      Loc = cast<StmtExpr>(this)->getLParenLoc();
      R1 = getSourceRange();
      return true;
    }
    case CXXFunctionalCastExprClass:
    case CStyleCastExprClass: {
      // Ignore an explicit cast to void unless the operand is a non-trivial
      // volatile lvalue.
      const CastExpr *CE = cast<CastExpr>(this);
      if (CE->getCastKind() == CK_ToVoid) {
        if (CE->getSubExpr()->isGLValue() &&
            CE->getSubExpr()->getType().isVolatileQualified()) {
          const DeclRefExpr *DRE =
              dyn_cast<DeclRefExpr>(CE->getSubExpr()->IgnoreParens());
          if (!(DRE && isa<VarDecl>(DRE->getDecl()) &&
                cast<VarDecl>(DRE->getDecl())->hasLocalStorage()) &&
              !isa<CallExpr>(CE->getSubExpr()->IgnoreParens())) {
            return CE->getSubExpr()->isUnusedResultAWarning(WarnE, Loc,
                                                            R1, R2, Ctx);
          }
        }
        return false;
      }
  
      // If this is a cast to a constructor conversion, check the operand.
      // Otherwise, the result of the cast is unused.
      if (CE->getCastKind() == CK_ConstructorConversion)
        return CE->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
  
      WarnE = this;
      if (const CXXFunctionalCastExpr *CXXCE =
              dyn_cast<CXXFunctionalCastExpr>(this)) {
        Loc = CXXCE->getBeginLoc();
        R1 = CXXCE->getSubExpr()->getSourceRange();
      } else {
        const CStyleCastExpr *CStyleCE = cast<CStyleCastExpr>(this);
        Loc = CStyleCE->getLParenLoc();
        R1 = CStyleCE->getSubExpr()->getSourceRange();
      }
      return true;
    }
    case ImplicitCastExprClass: {
      const CastExpr *ICE = cast<ImplicitCastExpr>(this);
  
      // lvalue-to-rvalue conversion on a volatile lvalue is a side-effect.
      if (ICE->getCastKind() == CK_LValueToRValue &&
          ICE->getSubExpr()->getType().isVolatileQualified())
        return false;
  
      return ICE->getSubExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }
    case CXXDefaultArgExprClass:
      return (cast<CXXDefaultArgExpr>(this)
              ->getExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));
    case CXXDefaultInitExprClass:
      return (cast<CXXDefaultInitExpr>(this)
              ->getExpr()->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx));
  
    case CXXNewExprClass:
      // FIXME: In theory, there might be new expressions that don't have side
      // effects (e.g. a placement new with an uninitialized POD).
    case CXXDeleteExprClass:
      return false;
    case MaterializeTemporaryExprClass:
      return cast<MaterializeTemporaryExpr>(this)->GetTemporaryExpr()
                 ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case CXXBindTemporaryExprClass:
      return cast<CXXBindTemporaryExpr>(this)->getSubExpr()
                 ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    case ExprWithCleanupsClass:
      return cast<ExprWithCleanups>(this)->getSubExpr()
                 ->isUnusedResultAWarning(WarnE, Loc, R1, R2, Ctx);
    }
  }
  
  /// isOBJCGCCandidate - Check if an expression is objc gc'able.
  /// returns true, if it is; false otherwise.
  bool Expr::isOBJCGCCandidate(ASTContext &Ctx) const {
    const Expr *E = IgnoreParens();
    switch (E->getStmtClass()) {
    default:
      return false;
    case ObjCIvarRefExprClass:
      return true;
    case Expr::UnaryOperatorClass:
      return cast<UnaryOperator>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
    case ImplicitCastExprClass:
      return cast<ImplicitCastExpr>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
    case MaterializeTemporaryExprClass:
      return cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr()
                                                        ->isOBJCGCCandidate(Ctx);
    case CStyleCastExprClass:
      return cast<CStyleCastExpr>(E)->getSubExpr()->isOBJCGCCandidate(Ctx);
    case DeclRefExprClass: {
      const Decl *D = cast<DeclRefExpr>(E)->getDecl();
  
      if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
        if (VD->hasGlobalStorage())
          return true;
        QualType T = VD->getType();
        // dereferencing to a  pointer is always a gc'able candidate,
        // unless it is __weak.
        return T->isPointerType() &&
               (Ctx.getObjCGCAttrKind(T) != Qualifiers::Weak);
      }
      return false;
    }
    case MemberExprClass: {
      const MemberExpr *M = cast<MemberExpr>(E);
      return M->getBase()->isOBJCGCCandidate(Ctx);
    }
    case ArraySubscriptExprClass:
      return cast<ArraySubscriptExpr>(E)->getBase()->isOBJCGCCandidate(Ctx);
    }
  }
  
  bool Expr::isBoundMemberFunction(ASTContext &Ctx) const {
    if (isTypeDependent())
      return false;
    return ClassifyLValue(Ctx) == Expr::LV_MemberFunction;
  }
  
  QualType Expr::findBoundMemberType(const Expr *expr) {
    assert(expr->hasPlaceholderType(BuiltinType::BoundMember));
  
    // Bound member expressions are always one of these possibilities:
    //   x->m      x.m      x->*y      x.*y
    // (possibly parenthesized)
  
    expr = expr->IgnoreParens();
    if (const MemberExpr *mem = dyn_cast<MemberExpr>(expr)) {
      assert(isa<CXXMethodDecl>(mem->getMemberDecl()));
      return mem->getMemberDecl()->getType();
    }
  
    if (const BinaryOperator *op = dyn_cast<BinaryOperator>(expr)) {
      QualType type = op->getRHS()->getType()->castAs<MemberPointerType>()
                        ->getPointeeType();
      assert(type->isFunctionType());
      return type;
    }
  
    assert(isa<UnresolvedMemberExpr>(expr) || isa<CXXPseudoDestructorExpr>(expr));
    return QualType();
  }
  
  static Expr *IgnoreImpCastsSingleStep(Expr *E) {
    if (auto *ICE = dyn_cast<ImplicitCastExpr>(E))
      return ICE->getSubExpr();
  
    if (auto *FE = dyn_cast<FullExpr>(E))
      return FE->getSubExpr();
  
    return E;
  }
  
  static Expr *IgnoreImpCastsExtraSingleStep(Expr *E) {
    // FIXME: Skip MaterializeTemporaryExpr and SubstNonTypeTemplateParmExpr in
    // addition to what IgnoreImpCasts() skips to account for the current
    // behaviour of IgnoreParenImpCasts().
    Expr *SubE = IgnoreImpCastsSingleStep(E);
    if (SubE != E)
      return SubE;
  
    if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
      return MTE->GetTemporaryExpr();
  
    if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
      return NTTP->getReplacement();
  
    return E;
  }
  
  static Expr *IgnoreCastsSingleStep(Expr *E) {
    if (auto *CE = dyn_cast<CastExpr>(E))
      return CE->getSubExpr();
  
    if (auto *FE = dyn_cast<FullExpr>(E))
      return FE->getSubExpr();
  
    if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
      return MTE->GetTemporaryExpr();
  
    if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
      return NTTP->getReplacement();
  
    return E;
  }
  
  static Expr *IgnoreLValueCastsSingleStep(Expr *E) {
    // Skip what IgnoreCastsSingleStep skips, except that only
    // lvalue-to-rvalue casts are skipped.
    if (auto *CE = dyn_cast<CastExpr>(E))
      if (CE->getCastKind() != CK_LValueToRValue)
        return E;
  
    return IgnoreCastsSingleStep(E);
  }
  
  static Expr *IgnoreBaseCastsSingleStep(Expr *E) {
    if (auto *CE = dyn_cast<CastExpr>(E))
      if (CE->getCastKind() == CK_DerivedToBase ||
          CE->getCastKind() == CK_UncheckedDerivedToBase ||
          CE->getCastKind() == CK_NoOp)
        return CE->getSubExpr();
  
    return E;
  }
  
  static Expr *IgnoreImplicitSingleStep(Expr *E) {
    Expr *SubE = IgnoreImpCastsSingleStep(E);
    if (SubE != E)
      return SubE;
  
    if (auto *MTE = dyn_cast<MaterializeTemporaryExpr>(E))
      return MTE->GetTemporaryExpr();
  
    if (auto *BTE = dyn_cast<CXXBindTemporaryExpr>(E))
      return BTE->getSubExpr();
  
    return E;
  }
  
  static Expr *IgnoreParensSingleStep(Expr *E) {
    if (auto *PE = dyn_cast<ParenExpr>(E))
      return PE->getSubExpr();
  
    if (auto *UO = dyn_cast<UnaryOperator>(E)) {
      if (UO->getOpcode() == UO_Extension)
        return UO->getSubExpr();
    }
  
    else if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
      if (!GSE->isResultDependent())
        return GSE->getResultExpr();
    }
  
    else if (auto *CE = dyn_cast<ChooseExpr>(E)) {
      if (!CE->isConditionDependent())
        return CE->getChosenSubExpr();
    }
  
    else if (auto *CE = dyn_cast<ConstantExpr>(E))
      return CE->getSubExpr();
  
    return E;
  }
  
  static Expr *IgnoreNoopCastsSingleStep(const ASTContext &Ctx, Expr *E) {
    if (auto *CE = dyn_cast<CastExpr>(E)) {
      // We ignore integer <-> casts that are of the same width, ptr<->ptr and
      // ptr<->int casts of the same width. We also ignore all identity casts.
      Expr *SubExpr = CE->getSubExpr();
      bool IsIdentityCast =
          Ctx.hasSameUnqualifiedType(E->getType(), SubExpr->getType());
      bool IsSameWidthCast =
          (E->getType()->isPointerType() || E->getType()->isIntegralType(Ctx)) &&
          (SubExpr->getType()->isPointerType() ||
           SubExpr->getType()->isIntegralType(Ctx)) &&
          (Ctx.getTypeSize(E->getType()) == Ctx.getTypeSize(SubExpr->getType()));
  
      if (IsIdentityCast || IsSameWidthCast)
        return SubExpr;
    }
  
    else if (auto *NTTP = dyn_cast<SubstNonTypeTemplateParmExpr>(E))
      return NTTP->getReplacement();
  
    return E;
  }
  
  static Expr *IgnoreExprNodesImpl(Expr *E) { return E; }
  template <typename FnTy, typename... FnTys>
  static Expr *IgnoreExprNodesImpl(Expr *E, FnTy &&Fn, FnTys &&... Fns) {
    return IgnoreExprNodesImpl(Fn(E), std::forward<FnTys>(Fns)...);
  }
  
  /// Given an expression E and functions Fn_1,...,Fn_n : Expr * -> Expr *,
  /// Recursively apply each of the functions to E until reaching a fixed point.
  /// Note that a null E is valid; in this case nothing is done.
  template <typename... FnTys>
  static Expr *IgnoreExprNodes(Expr *E, FnTys &&... Fns) {
    Expr *LastE = nullptr;
    while (E != LastE) {
      LastE = E;
      E = IgnoreExprNodesImpl(E, std::forward<FnTys>(Fns)...);
    }
    return E;
  }
  
  Expr *Expr::IgnoreImpCasts() {
    return IgnoreExprNodes(this, IgnoreImpCastsSingleStep);
  }
  
  Expr *Expr::IgnoreCasts() {
    return IgnoreExprNodes(this, IgnoreCastsSingleStep);
  }
  
  Expr *Expr::IgnoreImplicit() {
    return IgnoreExprNodes(this, IgnoreImplicitSingleStep);
  }
  
  Expr *Expr::IgnoreParens() {
    return IgnoreExprNodes(this, IgnoreParensSingleStep);
  }
  
  Expr *Expr::IgnoreParenImpCasts() {
    return IgnoreExprNodes(this, IgnoreParensSingleStep,
                           IgnoreImpCastsExtraSingleStep);
  }
  
  Expr *Expr::IgnoreParenCasts() {
    return IgnoreExprNodes(this, IgnoreParensSingleStep, IgnoreCastsSingleStep);
  }
  
  Expr *Expr::IgnoreConversionOperator() {
    if (auto *MCE = dyn_cast<CXXMemberCallExpr>(this)) {
      if (MCE->getMethodDecl() && isa<CXXConversionDecl>(MCE->getMethodDecl()))
        return MCE->getImplicitObjectArgument();
    }
    return this;
  }
  
  Expr *Expr::IgnoreParenLValueCasts() {
    return IgnoreExprNodes(this, IgnoreParensSingleStep,
                           IgnoreLValueCastsSingleStep);
  }
  
  Expr *Expr::ignoreParenBaseCasts() {
    return IgnoreExprNodes(this, IgnoreParensSingleStep,
                           IgnoreBaseCastsSingleStep);
  }
  
  Expr *Expr::IgnoreParenNoopCasts(const ASTContext &Ctx) {
    return IgnoreExprNodes(this, IgnoreParensSingleStep, [&Ctx](Expr *E) {
      return IgnoreNoopCastsSingleStep(Ctx, E);
    });
  }
  
  bool Expr::isDefaultArgument() const {
    const Expr *E = this;
    if (const MaterializeTemporaryExpr *M = dyn_cast<MaterializeTemporaryExpr>(E))
      E = M->GetTemporaryExpr();
  
    while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
      E = ICE->getSubExprAsWritten();
  
    return isa<CXXDefaultArgExpr>(E);
  }
  
  /// Skip over any no-op casts and any temporary-binding
  /// expressions.
  static const Expr *skipTemporaryBindingsNoOpCastsAndParens(const Expr *E) {
    if (const MaterializeTemporaryExpr *M = dyn_cast<MaterializeTemporaryExpr>(E))
      E = M->GetTemporaryExpr();
  
    while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getCastKind() == CK_NoOp)
        E = ICE->getSubExpr();
      else
        break;
    }
  
    while (const CXXBindTemporaryExpr *BE = dyn_cast<CXXBindTemporaryExpr>(E))
      E = BE->getSubExpr();
  
    while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getCastKind() == CK_NoOp)
        E = ICE->getSubExpr();
      else
        break;
    }
  
    return E->IgnoreParens();
  }
  
  /// isTemporaryObject - Determines if this expression produces a
  /// temporary of the given class type.
  bool Expr::isTemporaryObject(ASTContext &C, const CXXRecordDecl *TempTy) const {
    if (!C.hasSameUnqualifiedType(getType(), C.getTypeDeclType(TempTy)))
      return false;
  
    const Expr *E = skipTemporaryBindingsNoOpCastsAndParens(this);
  
    // Temporaries are by definition pr-values of class type.
    if (!E->Classify(C).isPRValue()) {
      // In this context, property reference is a message call and is pr-value.
      if (!isa<ObjCPropertyRefExpr>(E))
        return false;
    }
  
    // Black-list a few cases which yield pr-values of class type that don't
    // refer to temporaries of that type:
  
    // - implicit derived-to-base conversions
    if (isa<ImplicitCastExpr>(E)) {
      switch (cast<ImplicitCastExpr>(E)->getCastKind()) {
      case CK_DerivedToBase:
      case CK_UncheckedDerivedToBase:
        return false;
      default:
        break;
      }
    }
  
    // - member expressions (all)
    if (isa<MemberExpr>(E))
      return false;
  
    if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E))
      if (BO->isPtrMemOp())
        return false;
  
    // - opaque values (all)
    if (isa<OpaqueValueExpr>(E))
      return false;
  
    return true;
  }
  
  bool Expr::isImplicitCXXThis() const {
    const Expr *E = this;
  
    // Strip away parentheses and casts we don't care about.
    while (true) {
      if (const ParenExpr *Paren = dyn_cast<ParenExpr>(E)) {
        E = Paren->getSubExpr();
        continue;
      }
  
      if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
        if (ICE->getCastKind() == CK_NoOp ||
            ICE->getCastKind() == CK_LValueToRValue ||
            ICE->getCastKind() == CK_DerivedToBase ||
            ICE->getCastKind() == CK_UncheckedDerivedToBase) {
          E = ICE->getSubExpr();
          continue;
        }
      }
  
      if (const UnaryOperator* UnOp = dyn_cast<UnaryOperator>(E)) {
        if (UnOp->getOpcode() == UO_Extension) {
          E = UnOp->getSubExpr();
          continue;
        }
      }
  
      if (const MaterializeTemporaryExpr *M
                                        = dyn_cast<MaterializeTemporaryExpr>(E)) {
        E = M->GetTemporaryExpr();
        continue;
      }
  
      break;
    }
  
    if (const CXXThisExpr *This = dyn_cast<CXXThisExpr>(E))
      return This->isImplicit();
  
    return false;
  }
  
  /// hasAnyTypeDependentArguments - Determines if any of the expressions
  /// in Exprs is type-dependent.
  bool Expr::hasAnyTypeDependentArguments(ArrayRef<Expr *> Exprs) {
    for (unsigned I = 0; I < Exprs.size(); ++I)
      if (Exprs[I]->isTypeDependent())
        return true;
  
    return false;
  }
  
  bool Expr::isConstantInitializer(ASTContext &Ctx, bool IsForRef,
                                   const Expr **Culprit) const {
    assert(!isValueDependent() &&
           "Expression evaluator can't be called on a dependent expression.");
  
    // This function is attempting whether an expression is an initializer
    // which can be evaluated at compile-time. It very closely parallels
    // ConstExprEmitter in CGExprConstant.cpp; if they don't match, it
    // will lead to unexpected results.  Like ConstExprEmitter, it falls back
    // to isEvaluatable most of the time.
    //
    // If we ever capture reference-binding directly in the AST, we can
    // kill the second parameter.
  
    if (IsForRef) {
      EvalResult Result;
      if (EvaluateAsLValue(Result, Ctx) && !Result.HasSideEffects)
        return true;
      if (Culprit)
        *Culprit = this;
      return false;
    }
  
    switch (getStmtClass()) {
    default: break;
    case StringLiteralClass:
    case ObjCEncodeExprClass:
      return true;
    case CXXTemporaryObjectExprClass:
    case CXXConstructExprClass: {
      const CXXConstructExpr *CE = cast<CXXConstructExpr>(this);
  
      if (CE->getConstructor()->isTrivial() &&
          CE->getConstructor()->getParent()->hasTrivialDestructor()) {
        // Trivial default constructor
        if (!CE->getNumArgs()) return true;
  
        // Trivial copy constructor
        assert(CE->getNumArgs() == 1 && "trivial ctor with > 1 argument");
        return CE->getArg(0)->isConstantInitializer(Ctx, false, Culprit);
      }
  
      break;
    }
    case ConstantExprClass: {
      // FIXME: We should be able to return "true" here, but it can lead to extra
      // error messages. E.g. in Sema/array-init.c.
      const Expr *Exp = cast<ConstantExpr>(this)->getSubExpr();
      return Exp->isConstantInitializer(Ctx, false, Culprit);
    }
    case CompoundLiteralExprClass: {
      // This handles gcc's extension that allows global initializers like
      // "struct x {int x;} x = (struct x) {};".
      // FIXME: This accepts other cases it shouldn't!
      const Expr *Exp = cast<CompoundLiteralExpr>(this)->getInitializer();
      return Exp->isConstantInitializer(Ctx, false, Culprit);
    }
    case DesignatedInitUpdateExprClass: {
      const DesignatedInitUpdateExpr *DIUE = cast<DesignatedInitUpdateExpr>(this);
      return DIUE->getBase()->isConstantInitializer(Ctx, false, Culprit) &&
             DIUE->getUpdater()->isConstantInitializer(Ctx, false, Culprit);
    }
    case InitListExprClass: {
      const InitListExpr *ILE = cast<InitListExpr>(this);
      assert(ILE->isSemanticForm() && "InitListExpr must be in semantic form");
      if (ILE->getType()->isArrayType()) {
        unsigned numInits = ILE->getNumInits();
        for (unsigned i = 0; i < numInits; i++) {
          if (!ILE->getInit(i)->isConstantInitializer(Ctx, false, Culprit))
            return false;
        }
        return true;
      }
  
      if (ILE->getType()->isRecordType()) {
        unsigned ElementNo = 0;
        RecordDecl *RD = ILE->getType()->getAs<RecordType>()->getDecl();
        for (const auto *Field : RD->fields()) {
          // If this is a union, skip all the fields that aren't being initialized.
          if (RD->isUnion() && ILE->getInitializedFieldInUnion() != Field)
            continue;
  
          // Don't emit anonymous bitfields, they just affect layout.
          if (Field->isUnnamedBitfield())
            continue;
  
          if (ElementNo < ILE->getNumInits()) {
            const Expr *Elt = ILE->getInit(ElementNo++);
            if (Field->isBitField()) {
              // Bitfields have to evaluate to an integer.
              EvalResult Result;
              if (!Elt->EvaluateAsInt(Result, Ctx)) {
                if (Culprit)
                  *Culprit = Elt;
                return false;
              }
            } else {
              bool RefType = Field->getType()->isReferenceType();
              if (!Elt->isConstantInitializer(Ctx, RefType, Culprit))
                return false;
            }
          }
        }
        return true;
      }
  
      break;
    }
    case ImplicitValueInitExprClass:
    case NoInitExprClass:
      return true;
    case ParenExprClass:
      return cast<ParenExpr>(this)->getSubExpr()
        ->isConstantInitializer(Ctx, IsForRef, Culprit);
    case GenericSelectionExprClass:
      return cast<GenericSelectionExpr>(this)->getResultExpr()
        ->isConstantInitializer(Ctx, IsForRef, Culprit);
    case ChooseExprClass:
      if (cast<ChooseExpr>(this)->isConditionDependent()) {
        if (Culprit)
          *Culprit = this;
        return false;
      }
      return cast<ChooseExpr>(this)->getChosenSubExpr()
        ->isConstantInitializer(Ctx, IsForRef, Culprit);
    case UnaryOperatorClass: {
      const UnaryOperator* Exp = cast<UnaryOperator>(this);
      if (Exp->getOpcode() == UO_Extension)
        return Exp->getSubExpr()->isConstantInitializer(Ctx, false, Culprit);
      break;
    }
    case CXXFunctionalCastExprClass:
    case CXXStaticCastExprClass:
    case ImplicitCastExprClass:
    case CStyleCastExprClass:
    case ObjCBridgedCastExprClass:
    case CXXDynamicCastExprClass:
    case CXXReinterpretCastExprClass:
    case CXXConstCastExprClass: {
      const CastExpr *CE = cast<CastExpr>(this);
  
      // Handle misc casts we want to ignore.
      if (CE->getCastKind() == CK_NoOp ||
          CE->getCastKind() == CK_LValueToRValue ||
          CE->getCastKind() == CK_ToUnion ||
          CE->getCastKind() == CK_ConstructorConversion ||
          CE->getCastKind() == CK_NonAtomicToAtomic ||
          CE->getCastKind() == CK_AtomicToNonAtomic ||
          CE->getCastKind() == CK_IntToOCLSampler)
        return CE->getSubExpr()->isConstantInitializer(Ctx, false, Culprit);
  
      break;
    }
    case MaterializeTemporaryExprClass:
      return cast<MaterializeTemporaryExpr>(this)->GetTemporaryExpr()
        ->isConstantInitializer(Ctx, false, Culprit);
  
    case SubstNonTypeTemplateParmExprClass:
      return cast<SubstNonTypeTemplateParmExpr>(this)->getReplacement()
        ->isConstantInitializer(Ctx, false, Culprit);
    case CXXDefaultArgExprClass:
      return cast<CXXDefaultArgExpr>(this)->getExpr()
        ->isConstantInitializer(Ctx, false, Culprit);
    case CXXDefaultInitExprClass:
      return cast<CXXDefaultInitExpr>(this)->getExpr()
        ->isConstantInitializer(Ctx, false, Culprit);
    }
    // Allow certain forms of UB in constant initializers: signed integer
    // overflow and floating-point division by zero. We'll give a warning on
    // these, but they're common enough that we have to accept them.
    if (isEvaluatable(Ctx, SE_AllowUndefinedBehavior))
      return true;
    if (Culprit)
      *Culprit = this;
    return false;
  }
  
  bool CallExpr::isBuiltinAssumeFalse(const ASTContext &Ctx) const {
    const FunctionDecl* FD = getDirectCallee();
    if (!FD || (FD->getBuiltinID() != Builtin::BI__assume &&
                FD->getBuiltinID() != Builtin::BI__builtin_assume))
      return false;
  
    const Expr* Arg = getArg(0);
    bool ArgVal;
    return !Arg->isValueDependent() &&
           Arg->EvaluateAsBooleanCondition(ArgVal, Ctx) && !ArgVal;
  }
  
  namespace {
    /// Look for any side effects within a Stmt.
    class SideEffectFinder : public ConstEvaluatedExprVisitor<SideEffectFinder> {
      typedef ConstEvaluatedExprVisitor<SideEffectFinder> Inherited;
      const bool IncludePossibleEffects;
      bool HasSideEffects;
  
    public:
      explicit SideEffectFinder(const ASTContext &Context, bool IncludePossible)
        : Inherited(Context),
          IncludePossibleEffects(IncludePossible), HasSideEffects(false) { }
  
      bool hasSideEffects() const { return HasSideEffects; }
  
      void VisitExpr(const Expr *E) {
        if (!HasSideEffects &&
            E->HasSideEffects(Context, IncludePossibleEffects))
          HasSideEffects = true;
      }
    };
  }
  
  bool Expr::HasSideEffects(const ASTContext &Ctx,
                            bool IncludePossibleEffects) const {
    // In circumstances where we care about definite side effects instead of
    // potential side effects, we want to ignore expressions that are part of a
    // macro expansion as a potential side effect.
    if (!IncludePossibleEffects && getExprLoc().isMacroID())
      return false;
  
    if (isInstantiationDependent())
      return IncludePossibleEffects;
  
    switch (getStmtClass()) {
    case NoStmtClass:
    #define ABSTRACT_STMT(Type)
    #define STMT(Type, Base) case Type##Class:
    #define EXPR(Type, Base)
    #include "clang/AST/StmtNodes.inc"
      llvm_unreachable("unexpected Expr kind");
  
    case DependentScopeDeclRefExprClass:
    case CXXUnresolvedConstructExprClass:
    case CXXDependentScopeMemberExprClass:
    case UnresolvedLookupExprClass:
    case UnresolvedMemberExprClass:
    case PackExpansionExprClass:
    case SubstNonTypeTemplateParmPackExprClass:
    case FunctionParmPackExprClass:
    case TypoExprClass:
    case CXXFoldExprClass:
      llvm_unreachable("shouldn't see dependent / unresolved nodes here");
  
    case DeclRefExprClass:
    case ObjCIvarRefExprClass:
    case PredefinedExprClass:
    case IntegerLiteralClass:
    case FixedPointLiteralClass:
    case FloatingLiteralClass:
    case ImaginaryLiteralClass:
    case StringLiteralClass:
    case CharacterLiteralClass:
    case OffsetOfExprClass:
    case ImplicitValueInitExprClass:
    case UnaryExprOrTypeTraitExprClass:
    case AddrLabelExprClass:
    case GNUNullExprClass:
    case ArrayInitIndexExprClass:
    case NoInitExprClass:
    case CXXBoolLiteralExprClass:
    case CXXNullPtrLiteralExprClass:
    case CXXThisExprClass:
    case CXXScalarValueInitExprClass:
    case TypeTraitExprClass:
    case ArrayTypeTraitExprClass:
    case ExpressionTraitExprClass:
    case CXXNoexceptExprClass:
    case SizeOfPackExprClass:
    case ObjCStringLiteralClass:
    case ObjCEncodeExprClass:
    case ObjCBoolLiteralExprClass:
    case ObjCAvailabilityCheckExprClass:
    case CXXUuidofExprClass:
    case OpaqueValueExprClass:
    case SourceLocExprClass:
      // These never have a side-effect.
      return false;
  
    case ConstantExprClass:
      // FIXME: Move this into the "return false;" block above.
      return cast<ConstantExpr>(this)->getSubExpr()->HasSideEffects(
          Ctx, IncludePossibleEffects);
  
    case CallExprClass:
    case CXXOperatorCallExprClass:
    case CXXMemberCallExprClass:
    case CUDAKernelCallExprClass:
    case UserDefinedLiteralClass: {
      // We don't know a call definitely has side effects, except for calls
      // to pure/const functions that definitely don't.
      // If the call itself is considered side-effect free, check the operands.
      const Decl *FD = cast<CallExpr>(this)->getCalleeDecl();
      bool IsPure = FD && (FD->hasAttr<ConstAttr>() || FD->hasAttr<PureAttr>());
      if (IsPure || !IncludePossibleEffects)
        break;
      return true;
    }
  
    case BlockExprClass:
    case CXXBindTemporaryExprClass:
      if (!IncludePossibleEffects)
        break;
      return true;
  
    case MSPropertyRefExprClass:
    case MSPropertySubscriptExprClass:
    case CompoundAssignOperatorClass:
    case VAArgExprClass:
    case AtomicExprClass:
    case CXXThrowExprClass:
    case CXXNewExprClass:
    case CXXDeleteExprClass:
    case CoawaitExprClass:
    case DependentCoawaitExprClass:
    case CoyieldExprClass:
      // These always have a side-effect.
      return true;
  
    case StmtExprClass: {
      // StmtExprs have a side-effect if any substatement does.
      SideEffectFinder Finder(Ctx, IncludePossibleEffects);
      Finder.Visit(cast<StmtExpr>(this)->getSubStmt());
      return Finder.hasSideEffects();
    }
  
    case ExprWithCleanupsClass:
      if (IncludePossibleEffects)
        if (cast<ExprWithCleanups>(this)->cleanupsHaveSideEffects())
          return true;
      break;
  
    case ParenExprClass:
    case ArraySubscriptExprClass:
    case OMPArraySectionExprClass:
    case MemberExprClass:
    case ConditionalOperatorClass:
    case BinaryConditionalOperatorClass:
    case CompoundLiteralExprClass:
    case ExtVectorElementExprClass:
    case DesignatedInitExprClass:
    case DesignatedInitUpdateExprClass:
    case ArrayInitLoopExprClass:
    case ParenListExprClass:
    case CXXPseudoDestructorExprClass:
    case CXXStdInitializerListExprClass:
    case SubstNonTypeTemplateParmExprClass:
    case MaterializeTemporaryExprClass:
    case ShuffleVectorExprClass:
    case ConvertVectorExprClass:
    case AsTypeExprClass:
      // These have a side-effect if any subexpression does.
      break;
  
    case UnaryOperatorClass:
      if (cast<UnaryOperator>(this)->isIncrementDecrementOp())
        return true;
      break;
  
    case BinaryOperatorClass:
      if (cast<BinaryOperator>(this)->isAssignmentOp())
        return true;
      break;
  
    case InitListExprClass:
      // FIXME: The children for an InitListExpr doesn't include the array filler.
      if (const Expr *E = cast<InitListExpr>(this)->getArrayFiller())
        if (E->HasSideEffects(Ctx, IncludePossibleEffects))
          return true;
      break;
  
    case GenericSelectionExprClass:
      return cast<GenericSelectionExpr>(this)->getResultExpr()->
          HasSideEffects(Ctx, IncludePossibleEffects);
  
    case ChooseExprClass:
      return cast<ChooseExpr>(this)->getChosenSubExpr()->HasSideEffects(
          Ctx, IncludePossibleEffects);
  
    case CXXDefaultArgExprClass:
      return cast<CXXDefaultArgExpr>(this)->getExpr()->HasSideEffects(
          Ctx, IncludePossibleEffects);
  
    case CXXDefaultInitExprClass: {
      const FieldDecl *FD = cast<CXXDefaultInitExpr>(this)->getField();
      if (const Expr *E = FD->getInClassInitializer())
        return E->HasSideEffects(Ctx, IncludePossibleEffects);
      // If we've not yet parsed the initializer, assume it has side-effects.
      return true;
    }
  
    case CXXDynamicCastExprClass: {
      // A dynamic_cast expression has side-effects if it can throw.
      const CXXDynamicCastExpr *DCE = cast<CXXDynamicCastExpr>(this);
      if (DCE->getTypeAsWritten()->isReferenceType() &&
          DCE->getCastKind() == CK_Dynamic)
        return true;
      }
      LLVM_FALLTHROUGH;
    case ImplicitCastExprClass:
    case CStyleCastExprClass:
    case CXXStaticCastExprClass:
    case CXXReinterpretCastExprClass:
    case CXXConstCastExprClass:
    case CXXFunctionalCastExprClass:
    case BuiltinBitCastExprClass: {
      // While volatile reads are side-effecting in both C and C++, we treat them
      // as having possible (not definite) side-effects. This allows idiomatic
      // code to behave without warning, such as sizeof(*v) for a volatile-
      // qualified pointer.
      if (!IncludePossibleEffects)
        break;
  
      const CastExpr *CE = cast<CastExpr>(this);
      if (CE->getCastKind() == CK_LValueToRValue &&
          CE->getSubExpr()->getType().isVolatileQualified())
        return true;
      break;
    }
  
    case CXXTypeidExprClass:
      // typeid might throw if its subexpression is potentially-evaluated, so has
      // side-effects in that case whether or not its subexpression does.
      return cast<CXXTypeidExpr>(this)->isPotentiallyEvaluated();
  
    case CXXConstructExprClass:
    case CXXTemporaryObjectExprClass: {
      const CXXConstructExpr *CE = cast<CXXConstructExpr>(this);
      if (!CE->getConstructor()->isTrivial() && IncludePossibleEffects)
        return true;
      // A trivial constructor does not add any side-effects of its own. Just look
      // at its arguments.
      break;
    }
  
    case CXXInheritedCtorInitExprClass: {
      const auto *ICIE = cast<CXXInheritedCtorInitExpr>(this);
      if (!ICIE->getConstructor()->isTrivial() && IncludePossibleEffects)
        return true;
      break;
    }
  
    case LambdaExprClass: {
      const LambdaExpr *LE = cast<LambdaExpr>(this);
      for (Expr *E : LE->capture_inits())
        if (E->HasSideEffects(Ctx, IncludePossibleEffects))
          return true;
      return false;
    }
  
    case PseudoObjectExprClass: {
      // Only look for side-effects in the semantic form, and look past
      // OpaqueValueExpr bindings in that form.
      const PseudoObjectExpr *PO = cast<PseudoObjectExpr>(this);
      for (PseudoObjectExpr::const_semantics_iterator I = PO->semantics_begin(),
                                                      E = PO->semantics_end();
           I != E; ++I) {
        const Expr *Subexpr = *I;
        if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Subexpr))
          Subexpr = OVE->getSourceExpr();
        if (Subexpr->HasSideEffects(Ctx, IncludePossibleEffects))
          return true;
      }
      return false;
    }
  
    case ObjCBoxedExprClass:
    case ObjCArrayLiteralClass:
    case ObjCDictionaryLiteralClass:
    case ObjCSelectorExprClass:
    case ObjCProtocolExprClass:
    case ObjCIsaExprClass:
    case ObjCIndirectCopyRestoreExprClass:
    case ObjCSubscriptRefExprClass:
    case ObjCBridgedCastExprClass:
    case ObjCMessageExprClass:
    case ObjCPropertyRefExprClass:
    // FIXME: Classify these cases better.
      if (IncludePossibleEffects)
        return true;
      break;
    }
  
    // Recurse to children.
    for (const Stmt *SubStmt : children())
      if (SubStmt &&
          cast<Expr>(SubStmt)->HasSideEffects(Ctx, IncludePossibleEffects))
        return true;
  
    return false;
  }
  
  namespace {
    /// Look for a call to a non-trivial function within an expression.
    class NonTrivialCallFinder : public ConstEvaluatedExprVisitor<NonTrivialCallFinder>
    {
      typedef ConstEvaluatedExprVisitor<NonTrivialCallFinder> Inherited;
  
      bool NonTrivial;
  
    public:
      explicit NonTrivialCallFinder(const ASTContext &Context)
        : Inherited(Context), NonTrivial(false) { }
  
      bool hasNonTrivialCall() const { return NonTrivial; }
  
      void VisitCallExpr(const CallExpr *E) {
        if (const CXXMethodDecl *Method
            = dyn_cast_or_null<const CXXMethodDecl>(E->getCalleeDecl())) {
          if (Method->isTrivial()) {
            // Recurse to children of the call.
            Inherited::VisitStmt(E);
            return;
          }
        }
  
        NonTrivial = true;
      }
  
      void VisitCXXConstructExpr(const CXXConstructExpr *E) {
        if (E->getConstructor()->isTrivial()) {
          // Recurse to children of the call.
          Inherited::VisitStmt(E);
          return;
        }
  
        NonTrivial = true;
      }
  
      void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *E) {
        if (E->getTemporary()->getDestructor()->isTrivial()) {
          Inherited::VisitStmt(E);
          return;
        }
  
        NonTrivial = true;
      }
    };
  }
  
  bool Expr::hasNonTrivialCall(const ASTContext &Ctx) const {
    NonTrivialCallFinder Finder(Ctx);
    Finder.Visit(this);
    return Finder.hasNonTrivialCall();
  }
  
  /// isNullPointerConstant - C99 6.3.2.3p3 - Return whether this is a null
  /// pointer constant or not, as well as the specific kind of constant detected.
  /// Null pointer constants can be integer constant expressions with the
  /// value zero, casts of zero to void*, nullptr (C++0X), or __null
  /// (a GNU extension).
  Expr::NullPointerConstantKind
  Expr::isNullPointerConstant(ASTContext &Ctx,
                              NullPointerConstantValueDependence NPC) const {
    if (isValueDependent() &&
        (!Ctx.getLangOpts().CPlusPlus11 || Ctx.getLangOpts().MSVCCompat)) {
      switch (NPC) {
      case NPC_NeverValueDependent:
        llvm_unreachable("Unexpected value dependent expression!");
      case NPC_ValueDependentIsNull:
        if (isTypeDependent() || getType()->isIntegralType(Ctx))
          return NPCK_ZeroExpression;
        else
          return NPCK_NotNull;
  
      case NPC_ValueDependentIsNotNull:
        return NPCK_NotNull;
      }
    }
  
    // Strip off a cast to void*, if it exists. Except in C++.
    if (const ExplicitCastExpr *CE = dyn_cast<ExplicitCastExpr>(this)) {
      if (!Ctx.getLangOpts().CPlusPlus) {
        // Check that it is a cast to void*.
        if (const PointerType *PT = CE->getType()->getAs<PointerType>()) {
          QualType Pointee = PT->getPointeeType();
          Qualifiers Qs = Pointee.getQualifiers();
          // Only (void*)0 or equivalent are treated as nullptr. If pointee type
          // has non-default address space it is not treated as nullptr.
          // (__generic void*)0 in OpenCL 2.0 should not be treated as nullptr
          // since it cannot be assigned to a pointer to constant address space.
          if ((Ctx.getLangOpts().OpenCLVersion >= 200 &&
               Pointee.getAddressSpace() == LangAS::opencl_generic) ||
              (Ctx.getLangOpts().OpenCL &&
               Ctx.getLangOpts().OpenCLVersion < 200 &&
               Pointee.getAddressSpace() == LangAS::opencl_private))
            Qs.removeAddressSpace();
  
          if (Pointee->isVoidType() && Qs.empty() && // to void*
              CE->getSubExpr()->getType()->isIntegerType()) // from int
            return CE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
        }
      }
    } else if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(this)) {
      // Ignore the ImplicitCastExpr type entirely.
      return ICE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const ParenExpr *PE = dyn_cast<ParenExpr>(this)) {
      // Accept ((void*)0) as a null pointer constant, as many other
      // implementations do.
      return PE->getSubExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const GenericSelectionExpr *GE =
                 dyn_cast<GenericSelectionExpr>(this)) {
      if (GE->isResultDependent())
        return NPCK_NotNull;
      return GE->getResultExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const ChooseExpr *CE = dyn_cast<ChooseExpr>(this)) {
      if (CE->isConditionDependent())
        return NPCK_NotNull;
      return CE->getChosenSubExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const CXXDefaultArgExpr *DefaultArg
                 = dyn_cast<CXXDefaultArgExpr>(this)) {
      // See through default argument expressions.
      return DefaultArg->getExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const CXXDefaultInitExpr *DefaultInit
                 = dyn_cast<CXXDefaultInitExpr>(this)) {
      // See through default initializer expressions.
      return DefaultInit->getExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (isa<GNUNullExpr>(this)) {
      // The GNU __null extension is always a null pointer constant.
      return NPCK_GNUNull;
    } else if (const MaterializeTemporaryExpr *M
                                     = dyn_cast<MaterializeTemporaryExpr>(this)) {
      return M->GetTemporaryExpr()->isNullPointerConstant(Ctx, NPC);
    } else if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(this)) {
      if (const Expr *Source = OVE->getSourceExpr())
        return Source->isNullPointerConstant(Ctx, NPC);
    }
  
    // C++11 nullptr_t is always a null pointer constant.
    if (getType()->isNullPtrType())
      return NPCK_CXX11_nullptr;
  
    if (const RecordType *UT = getType()->getAsUnionType())
      if (!Ctx.getLangOpts().CPlusPlus11 &&
          UT && UT->getDecl()->hasAttr<TransparentUnionAttr>())
        if (const CompoundLiteralExpr *CLE = dyn_cast<CompoundLiteralExpr>(this)){
          const Expr *InitExpr = CLE->getInitializer();
          if (const InitListExpr *ILE = dyn_cast<InitListExpr>(InitExpr))
            return ILE->getInit(0)->isNullPointerConstant(Ctx, NPC);
        }
    // This expression must be an integer type.
    if (!getType()->isIntegerType() ||
        (Ctx.getLangOpts().CPlusPlus && getType()->isEnumeralType()))
      return NPCK_NotNull;
  
    if (Ctx.getLangOpts().CPlusPlus11) {
      // C++11 [conv.ptr]p1: A null pointer constant is an integer literal with
      // value zero or a prvalue of type std::nullptr_t.
      // Microsoft mode permits C++98 rules reflecting MSVC behavior.
      const IntegerLiteral *Lit = dyn_cast<IntegerLiteral>(this);
      if (Lit && !Lit->getValue())
        return NPCK_ZeroLiteral;
      else if (!Ctx.getLangOpts().MSVCCompat || !isCXX98IntegralConstantExpr(Ctx))
        return NPCK_NotNull;
    } else {
      // If we have an integer constant expression, we need to *evaluate* it and
      // test for the value 0.
      if (!isIntegerConstantExpr(Ctx))
        return NPCK_NotNull;
    }
  
    if (EvaluateKnownConstInt(Ctx) != 0)
      return NPCK_NotNull;
  
    if (isa<IntegerLiteral>(this))
      return NPCK_ZeroLiteral;
    return NPCK_ZeroExpression;
  }
  
  /// If this expression is an l-value for an Objective C
  /// property, find the underlying property reference expression.
  const ObjCPropertyRefExpr *Expr::getObjCProperty() const {
    const Expr *E = this;
    while (true) {
      assert((E->getValueKind() == VK_LValue &&
              E->getObjectKind() == OK_ObjCProperty) &&
             "expression is not a property reference");
      E = E->IgnoreParenCasts();
      if (const BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
        if (BO->getOpcode() == BO_Comma) {
          E = BO->getRHS();
          continue;
        }
      }
  
      break;
    }
  
    return cast<ObjCPropertyRefExpr>(E);
  }
  
  bool Expr::isObjCSelfExpr() const {
    const Expr *E = IgnoreParenImpCasts();
  
    const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
    if (!DRE)
      return false;
  
    const ImplicitParamDecl *Param = dyn_cast<ImplicitParamDecl>(DRE->getDecl());
    if (!Param)
      return false;
  
    const ObjCMethodDecl *M = dyn_cast<ObjCMethodDecl>(Param->getDeclContext());
    if (!M)
      return false;
  
    return M->getSelfDecl() == Param;
  }
  
  FieldDecl *Expr::getSourceBitField() {
    Expr *E = this->IgnoreParens();
  
    while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getCastKind() == CK_LValueToRValue ||
          (ICE->getValueKind() != VK_RValue && ICE->getCastKind() == CK_NoOp))
        E = ICE->getSubExpr()->IgnoreParens();
      else
        break;
    }
  
    if (MemberExpr *MemRef = dyn_cast<MemberExpr>(E))
      if (FieldDecl *Field = dyn_cast<FieldDecl>(MemRef->getMemberDecl()))
        if (Field->isBitField())
          return Field;
  
    if (ObjCIvarRefExpr *IvarRef = dyn_cast<ObjCIvarRefExpr>(E)) {
      FieldDecl *Ivar = IvarRef->getDecl();
      if (Ivar->isBitField())
        return Ivar;
    }
  
    if (DeclRefExpr *DeclRef = dyn_cast<DeclRefExpr>(E)) {
      if (FieldDecl *Field = dyn_cast<FieldDecl>(DeclRef->getDecl()))
        if (Field->isBitField())
          return Field;
  
      if (BindingDecl *BD = dyn_cast<BindingDecl>(DeclRef->getDecl()))
        if (Expr *E = BD->getBinding())
          return E->getSourceBitField();
    }
  
    if (BinaryOperator *BinOp = dyn_cast<BinaryOperator>(E)) {
      if (BinOp->isAssignmentOp() && BinOp->getLHS())
        return BinOp->getLHS()->getSourceBitField();
  
      if (BinOp->getOpcode() == BO_Comma && BinOp->getRHS())
        return BinOp->getRHS()->getSourceBitField();
    }
  
    if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E))
      if (UnOp->isPrefix() && UnOp->isIncrementDecrementOp())
        return UnOp->getSubExpr()->getSourceBitField();
  
    return nullptr;
  }
  
  bool Expr::refersToVectorElement() const {
    // FIXME: Why do we not just look at the ObjectKind here?
    const Expr *E = this->IgnoreParens();
  
    while (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
      if (ICE->getValueKind() != VK_RValue &&
          ICE->getCastKind() == CK_NoOp)
        E = ICE->getSubExpr()->IgnoreParens();
      else
        break;
    }
  
    if (const ArraySubscriptExpr *ASE = dyn_cast<ArraySubscriptExpr>(E))
      return ASE->getBase()->getType()->isVectorType();
  
    if (isa<ExtVectorElementExpr>(E))
      return true;
  
    if (auto *DRE = dyn_cast<DeclRefExpr>(E))
      if (auto *BD = dyn_cast<BindingDecl>(DRE->getDecl()))
        if (auto *E = BD->getBinding())
          return E->refersToVectorElement();
  
    return false;
  }
  
  bool Expr::refersToGlobalRegisterVar() const {
    const Expr *E = this->IgnoreParenImpCasts();
  
    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
      if (const auto *VD = dyn_cast<VarDecl>(DRE->getDecl()))
        if (VD->getStorageClass() == SC_Register &&
            VD->hasAttr<AsmLabelAttr>() && !VD->isLocalVarDecl())
          return true;
  
    return false;
  }
  
  /// isArrow - Return true if the base expression is a pointer to vector,
  /// return false if the base expression is a vector.
  bool ExtVectorElementExpr::isArrow() const {
    return getBase()->getType()->isPointerType();
  }
  
  unsigned ExtVectorElementExpr::getNumElements() const {
    if (const VectorType *VT = getType()->getAs<VectorType>())
      return VT->getNumElements();
    return 1;
  }
  
  /// containsDuplicateElements - Return true if any element access is repeated.
  bool ExtVectorElementExpr::containsDuplicateElements() const {
    // FIXME: Refactor this code to an accessor on the AST node which returns the
    // "type" of component access, and share with code below and in Sema.
    StringRef Comp = Accessor->getName();
  
    // Halving swizzles do not contain duplicate elements.
    if (Comp == "hi" || Comp == "lo" || Comp == "even" || Comp == "odd")
      return false;
  
    // Advance past s-char prefix on hex swizzles.
    if (Comp[0] == 's' || Comp[0] == 'S')
      Comp = Comp.substr(1);
  
    for (unsigned i = 0, e = Comp.size(); i != e; ++i)
      if (Comp.substr(i + 1).find(Comp[i]) != StringRef::npos)
          return true;
  
    return false;
  }
  
  /// getEncodedElementAccess - We encode the fields as a llvm ConstantArray.
  void ExtVectorElementExpr::getEncodedElementAccess(
      SmallVectorImpl<uint32_t> &Elts) const {
    StringRef Comp = Accessor->getName();
    bool isNumericAccessor = false;
    if (Comp[0] == 's' || Comp[0] == 'S') {
      Comp = Comp.substr(1);
      isNumericAccessor = true;
    }
  
    bool isHi =   Comp == "hi";
    bool isLo =   Comp == "lo";
    bool isEven = Comp == "even";
    bool isOdd  = Comp == "odd";
  
    for (unsigned i = 0, e = getNumElements(); i != e; ++i) {
      uint64_t Index;
  
      if (isHi)
        Index = e + i;
      else if (isLo)
        Index = i;
      else if (isEven)
        Index = 2 * i;
      else if (isOdd)
        Index = 2 * i + 1;
      else
        Index = ExtVectorType::getAccessorIdx(Comp[i], isNumericAccessor);
  
      Elts.push_back(Index);
    }
  }
  
  ShuffleVectorExpr::ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr*> args,
                                       QualType Type, SourceLocation BLoc,
                                       SourceLocation RP)
     : Expr(ShuffleVectorExprClass, Type, VK_RValue, OK_Ordinary,
            Type->isDependentType(), Type->isDependentType(),
            Type->isInstantiationDependentType(),
            Type->containsUnexpandedParameterPack()),
       BuiltinLoc(BLoc), RParenLoc(RP), NumExprs(args.size())
  {
    SubExprs = new (C) Stmt*[args.size()];
    for (unsigned i = 0; i != args.size(); i++) {
      if (args[i]->isTypeDependent())
        ExprBits.TypeDependent = true;
      if (args[i]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (args[i]->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (args[i]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
  
      SubExprs[i] = args[i];
    }
  }
  
  void ShuffleVectorExpr::setExprs(const ASTContext &C, ArrayRef<Expr *> Exprs) {
    if (SubExprs) C.Deallocate(SubExprs);
  
    this->NumExprs = Exprs.size();
    SubExprs = new (C) Stmt*[NumExprs];
    memcpy(SubExprs, Exprs.data(), sizeof(Expr *) * Exprs.size());
  }
  
  GenericSelectionExpr::GenericSelectionExpr(
      const ASTContext &, SourceLocation GenericLoc, Expr *ControllingExpr,
      ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
      SourceLocation DefaultLoc, SourceLocation RParenLoc,
      bool ContainsUnexpandedParameterPack, unsigned ResultIndex)
      : Expr(GenericSelectionExprClass, AssocExprs[ResultIndex]->getType(),
             AssocExprs[ResultIndex]->getValueKind(),
             AssocExprs[ResultIndex]->getObjectKind(),
             AssocExprs[ResultIndex]->isTypeDependent(),
             AssocExprs[ResultIndex]->isValueDependent(),
             AssocExprs[ResultIndex]->isInstantiationDependent(),
             ContainsUnexpandedParameterPack),
        NumAssocs(AssocExprs.size()), ResultIndex(ResultIndex),
        DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
    assert(AssocTypes.size() == AssocExprs.size() &&
           "Must have the same number of association expressions"
           " and TypeSourceInfo!");
    assert(ResultIndex < NumAssocs && "ResultIndex is out-of-bounds!");
  
    GenericSelectionExprBits.GenericLoc = GenericLoc;
    getTrailingObjects<Stmt *>()[ControllingIndex] = ControllingExpr;
    std::copy(AssocExprs.begin(), AssocExprs.end(),
              getTrailingObjects<Stmt *>() + AssocExprStartIndex);
    std::copy(AssocTypes.begin(), AssocTypes.end(),
              getTrailingObjects<TypeSourceInfo *>());
  }
  
  GenericSelectionExpr::GenericSelectionExpr(
      const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
      ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
      SourceLocation DefaultLoc, SourceLocation RParenLoc,
      bool ContainsUnexpandedParameterPack)
      : Expr(GenericSelectionExprClass, Context.DependentTy, VK_RValue,
             OK_Ordinary,
             /*isTypeDependent=*/true,
             /*isValueDependent=*/true,
             /*isInstantiationDependent=*/true, ContainsUnexpandedParameterPack),
        NumAssocs(AssocExprs.size()), ResultIndex(ResultDependentIndex),
        DefaultLoc(DefaultLoc), RParenLoc(RParenLoc) {
    assert(AssocTypes.size() == AssocExprs.size() &&
           "Must have the same number of association expressions"
           " and TypeSourceInfo!");
  
    GenericSelectionExprBits.GenericLoc = GenericLoc;
    getTrailingObjects<Stmt *>()[ControllingIndex] = ControllingExpr;
    std::copy(AssocExprs.begin(), AssocExprs.end(),
              getTrailingObjects<Stmt *>() + AssocExprStartIndex);
    std::copy(AssocTypes.begin(), AssocTypes.end(),
              getTrailingObjects<TypeSourceInfo *>());
  }
  
  GenericSelectionExpr::GenericSelectionExpr(EmptyShell Empty, unsigned NumAssocs)
      : Expr(GenericSelectionExprClass, Empty), NumAssocs(NumAssocs) {}
  
  GenericSelectionExpr *GenericSelectionExpr::Create(
      const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
      ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
      SourceLocation DefaultLoc, SourceLocation RParenLoc,
      bool ContainsUnexpandedParameterPack, unsigned ResultIndex) {
    unsigned NumAssocs = AssocExprs.size();
    void *Mem = Context.Allocate(
        totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
        alignof(GenericSelectionExpr));
    return new (Mem) GenericSelectionExpr(
        Context, GenericLoc, ControllingExpr, AssocTypes, AssocExprs, DefaultLoc,
        RParenLoc, ContainsUnexpandedParameterPack, ResultIndex);
  }
  
  GenericSelectionExpr *GenericSelectionExpr::Create(
      const ASTContext &Context, SourceLocation GenericLoc, Expr *ControllingExpr,
      ArrayRef<TypeSourceInfo *> AssocTypes, ArrayRef<Expr *> AssocExprs,
      SourceLocation DefaultLoc, SourceLocation RParenLoc,
      bool ContainsUnexpandedParameterPack) {
    unsigned NumAssocs = AssocExprs.size();
    void *Mem = Context.Allocate(
        totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
        alignof(GenericSelectionExpr));
    return new (Mem) GenericSelectionExpr(
        Context, GenericLoc, ControllingExpr, AssocTypes, AssocExprs, DefaultLoc,
        RParenLoc, ContainsUnexpandedParameterPack);
  }
  
  GenericSelectionExpr *
  GenericSelectionExpr::CreateEmpty(const ASTContext &Context,
                                    unsigned NumAssocs) {
    void *Mem = Context.Allocate(
        totalSizeToAlloc<Stmt *, TypeSourceInfo *>(1 + NumAssocs, NumAssocs),
        alignof(GenericSelectionExpr));
    return new (Mem) GenericSelectionExpr(EmptyShell(), NumAssocs);
  }
  
  //===----------------------------------------------------------------------===//
  //  DesignatedInitExpr
  //===----------------------------------------------------------------------===//
  
  IdentifierInfo *DesignatedInitExpr::Designator::getFieldName() const {
    assert(Kind == FieldDesignator && "Only valid on a field designator");
    if (Field.NameOrField & 0x01)
      return reinterpret_cast<IdentifierInfo *>(Field.NameOrField&~0x01);
    else
      return getField()->getIdentifier();
  }
  
  DesignatedInitExpr::DesignatedInitExpr(const ASTContext &C, QualType Ty,
                                         llvm::ArrayRef<Designator> Designators,
                                         SourceLocation EqualOrColonLoc,
                                         bool GNUSyntax,
                                         ArrayRef<Expr*> IndexExprs,
                                         Expr *Init)
    : Expr(DesignatedInitExprClass, Ty,
           Init->getValueKind(), Init->getObjectKind(),
           Init->isTypeDependent(), Init->isValueDependent(),
           Init->isInstantiationDependent(),
           Init->containsUnexpandedParameterPack()),
      EqualOrColonLoc(EqualOrColonLoc), GNUSyntax(GNUSyntax),
      NumDesignators(Designators.size()), NumSubExprs(IndexExprs.size() + 1) {
    this->Designators = new (C) Designator[NumDesignators];
  
    // Record the initializer itself.
    child_iterator Child = child_begin();
    *Child++ = Init;
  
    // Copy the designators and their subexpressions, computing
    // value-dependence along the way.
    unsigned IndexIdx = 0;
    for (unsigned I = 0; I != NumDesignators; ++I) {
      this->Designators[I] = Designators[I];
  
      if (this->Designators[I].isArrayDesignator()) {
        // Compute type- and value-dependence.
        Expr *Index = IndexExprs[IndexIdx];
        if (Index->isTypeDependent() || Index->isValueDependent())
          ExprBits.TypeDependent = ExprBits.ValueDependent = true;
        if (Index->isInstantiationDependent())
          ExprBits.InstantiationDependent = true;
        // Propagate unexpanded parameter packs.
        if (Index->containsUnexpandedParameterPack())
          ExprBits.ContainsUnexpandedParameterPack = true;
  
        // Copy the index expressions into permanent storage.
        *Child++ = IndexExprs[IndexIdx++];
      } else if (this->Designators[I].isArrayRangeDesignator()) {
        // Compute type- and value-dependence.
        Expr *Start = IndexExprs[IndexIdx];
        Expr *End = IndexExprs[IndexIdx + 1];
        if (Start->isTypeDependent() || Start->isValueDependent() ||
            End->isTypeDependent() || End->isValueDependent()) {
          ExprBits.TypeDependent = ExprBits.ValueDependent = true;
          ExprBits.InstantiationDependent = true;
        } else if (Start->isInstantiationDependent() ||
                   End->isInstantiationDependent()) {
          ExprBits.InstantiationDependent = true;
        }
  
        // Propagate unexpanded parameter packs.
        if (Start->containsUnexpandedParameterPack() ||
            End->containsUnexpandedParameterPack())
          ExprBits.ContainsUnexpandedParameterPack = true;
  
        // Copy the start/end expressions into permanent storage.
        *Child++ = IndexExprs[IndexIdx++];
        *Child++ = IndexExprs[IndexIdx++];
      }
    }
  
    assert(IndexIdx == IndexExprs.size() && "Wrong number of index expressions");
  }
  
  DesignatedInitExpr *
  DesignatedInitExpr::Create(const ASTContext &C,
                             llvm::ArrayRef<Designator> Designators,
                             ArrayRef<Expr*> IndexExprs,
                             SourceLocation ColonOrEqualLoc,
                             bool UsesColonSyntax, Expr *Init) {
    void *Mem = C.Allocate(totalSizeToAlloc<Stmt *>(IndexExprs.size() + 1),
                           alignof(DesignatedInitExpr));
    return new (Mem) DesignatedInitExpr(C, C.VoidTy, Designators,
                                        ColonOrEqualLoc, UsesColonSyntax,
                                        IndexExprs, Init);
  }
  
  DesignatedInitExpr *DesignatedInitExpr::CreateEmpty(const ASTContext &C,
                                                      unsigned NumIndexExprs) {
    void *Mem = C.Allocate(totalSizeToAlloc<Stmt *>(NumIndexExprs + 1),
                           alignof(DesignatedInitExpr));
    return new (Mem) DesignatedInitExpr(NumIndexExprs + 1);
  }
  
  void DesignatedInitExpr::setDesignators(const ASTContext &C,
                                          const Designator *Desigs,
                                          unsigned NumDesigs) {
    Designators = new (C) Designator[NumDesigs];
    NumDesignators = NumDesigs;
    for (unsigned I = 0; I != NumDesigs; ++I)
      Designators[I] = Desigs[I];
  }
  
  SourceRange DesignatedInitExpr::getDesignatorsSourceRange() const {
    DesignatedInitExpr *DIE = const_cast<DesignatedInitExpr*>(this);
    if (size() == 1)
      return DIE->getDesignator(0)->getSourceRange();
    return SourceRange(DIE->getDesignator(0)->getBeginLoc(),
                       DIE->getDesignator(size() - 1)->getEndLoc());
  }
  
  SourceLocation DesignatedInitExpr::getBeginLoc() const {
    SourceLocation StartLoc;
    auto *DIE = const_cast<DesignatedInitExpr *>(this);
    Designator &First = *DIE->getDesignator(0);
    if (First.isFieldDesignator()) {
      if (GNUSyntax)
        StartLoc = SourceLocation::getFromRawEncoding(First.Field.FieldLoc);
      else
        StartLoc = SourceLocation::getFromRawEncoding(First.Field.DotLoc);
    } else
      StartLoc =
        SourceLocation::getFromRawEncoding(First.ArrayOrRange.LBracketLoc);
    return StartLoc;
  }
  
  SourceLocation DesignatedInitExpr::getEndLoc() const {
    return getInit()->getEndLoc();
  }
  
  Expr *DesignatedInitExpr::getArrayIndex(const Designator& D) const {
    assert(D.Kind == Designator::ArrayDesignator && "Requires array designator");
    return getSubExpr(D.ArrayOrRange.Index + 1);
  }
  
  Expr *DesignatedInitExpr::getArrayRangeStart(const Designator &D) const {
    assert(D.Kind == Designator::ArrayRangeDesignator &&
           "Requires array range designator");
    return getSubExpr(D.ArrayOrRange.Index + 1);
  }
  
  Expr *DesignatedInitExpr::getArrayRangeEnd(const Designator &D) const {
    assert(D.Kind == Designator::ArrayRangeDesignator &&
           "Requires array range designator");
    return getSubExpr(D.ArrayOrRange.Index + 2);
  }
  
  /// Replaces the designator at index @p Idx with the series
  /// of designators in [First, Last).
  void DesignatedInitExpr::ExpandDesignator(const ASTContext &C, unsigned Idx,
                                            const Designator *First,
                                            const Designator *Last) {
    unsigned NumNewDesignators = Last - First;
    if (NumNewDesignators == 0) {
      std::copy_backward(Designators + Idx + 1,
                         Designators + NumDesignators,
                         Designators + Idx);
      --NumNewDesignators;
      return;
    } else if (NumNewDesignators == 1) {
      Designators[Idx] = *First;
      return;
    }
  
    Designator *NewDesignators
      = new (C) Designator[NumDesignators - 1 + NumNewDesignators];
    std::copy(Designators, Designators + Idx, NewDesignators);
    std::copy(First, Last, NewDesignators + Idx);
    std::copy(Designators + Idx + 1, Designators + NumDesignators,
              NewDesignators + Idx + NumNewDesignators);
    Designators = NewDesignators;
    NumDesignators = NumDesignators - 1 + NumNewDesignators;
  }
  
  DesignatedInitUpdateExpr::DesignatedInitUpdateExpr(const ASTContext &C,
      SourceLocation lBraceLoc, Expr *baseExpr, SourceLocation rBraceLoc)
    : Expr(DesignatedInitUpdateExprClass, baseExpr->getType(), VK_RValue,
           OK_Ordinary, false, false, false, false) {
    BaseAndUpdaterExprs[0] = baseExpr;
  
    InitListExpr *ILE = new (C) InitListExpr(C, lBraceLoc, None, rBraceLoc);
    ILE->setType(baseExpr->getType());
    BaseAndUpdaterExprs[1] = ILE;
  }
  
  SourceLocation DesignatedInitUpdateExpr::getBeginLoc() const {
    return getBase()->getBeginLoc();
  }
  
  SourceLocation DesignatedInitUpdateExpr::getEndLoc() const {
    return getBase()->getEndLoc();
  }
  
  ParenListExpr::ParenListExpr(SourceLocation LParenLoc, ArrayRef<Expr *> Exprs,
                               SourceLocation RParenLoc)
      : Expr(ParenListExprClass, QualType(), VK_RValue, OK_Ordinary, false, false,
             false, false),
        LParenLoc(LParenLoc), RParenLoc(RParenLoc) {
    ParenListExprBits.NumExprs = Exprs.size();
  
    for (unsigned I = 0, N = Exprs.size(); I != N; ++I) {
      if (Exprs[I]->isTypeDependent())
        ExprBits.TypeDependent = true;
      if (Exprs[I]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (Exprs[I]->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (Exprs[I]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
  
      getTrailingObjects<Stmt *>()[I] = Exprs[I];
    }
  }
  
  ParenListExpr::ParenListExpr(EmptyShell Empty, unsigned NumExprs)
      : Expr(ParenListExprClass, Empty) {
    ParenListExprBits.NumExprs = NumExprs;
  }
  
  ParenListExpr *ParenListExpr::Create(const ASTContext &Ctx,
                                       SourceLocation LParenLoc,
                                       ArrayRef<Expr *> Exprs,
                                       SourceLocation RParenLoc) {
    void *Mem = Ctx.Allocate(totalSizeToAlloc<Stmt *>(Exprs.size()),
                             alignof(ParenListExpr));
    return new (Mem) ParenListExpr(LParenLoc, Exprs, RParenLoc);
  }
  
  ParenListExpr *ParenListExpr::CreateEmpty(const ASTContext &Ctx,
                                            unsigned NumExprs) {
    void *Mem =
        Ctx.Allocate(totalSizeToAlloc<Stmt *>(NumExprs), alignof(ParenListExpr));
    return new (Mem) ParenListExpr(EmptyShell(), NumExprs);
  }
  
  const OpaqueValueExpr *OpaqueValueExpr::findInCopyConstruct(const Expr *e) {
    if (const ExprWithCleanups *ewc = dyn_cast<ExprWithCleanups>(e))
      e = ewc->getSubExpr();
    if (const MaterializeTemporaryExpr *m = dyn_cast<MaterializeTemporaryExpr>(e))
      e = m->GetTemporaryExpr();
    e = cast<CXXConstructExpr>(e)->getArg(0);
    while (const ImplicitCastExpr *ice = dyn_cast<ImplicitCastExpr>(e))
      e = ice->getSubExpr();
    return cast<OpaqueValueExpr>(e);
  }
  
  PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &Context,
                                             EmptyShell sh,
                                             unsigned numSemanticExprs) {
    void *buffer =
        Context.Allocate(totalSizeToAlloc<Expr *>(1 + numSemanticExprs),
                         alignof(PseudoObjectExpr));
    return new(buffer) PseudoObjectExpr(sh, numSemanticExprs);
  }
  
  PseudoObjectExpr::PseudoObjectExpr(EmptyShell shell, unsigned numSemanticExprs)
    : Expr(PseudoObjectExprClass, shell) {
    PseudoObjectExprBits.NumSubExprs = numSemanticExprs + 1;
  }
  
  PseudoObjectExpr *PseudoObjectExpr::Create(const ASTContext &C, Expr *syntax,
                                             ArrayRef<Expr*> semantics,
                                             unsigned resultIndex) {
    assert(syntax && "no syntactic expression!");
    assert(semantics.size() && "no semantic expressions!");
  
    QualType type;
    ExprValueKind VK;
    if (resultIndex == NoResult) {
      type = C.VoidTy;
      VK = VK_RValue;
    } else {
      assert(resultIndex < semantics.size());
      type = semantics[resultIndex]->getType();
      VK = semantics[resultIndex]->getValueKind();
      assert(semantics[resultIndex]->getObjectKind() == OK_Ordinary);
    }
  
    void *buffer = C.Allocate(totalSizeToAlloc<Expr *>(semantics.size() + 1),
                              alignof(PseudoObjectExpr));
    return new(buffer) PseudoObjectExpr(type, VK, syntax, semantics,
                                        resultIndex);
  }
  
  PseudoObjectExpr::PseudoObjectExpr(QualType type, ExprValueKind VK,
                                     Expr *syntax, ArrayRef<Expr*> semantics,
                                     unsigned resultIndex)
    : Expr(PseudoObjectExprClass, type, VK, OK_Ordinary,
           /*filled in at end of ctor*/ false, false, false, false) {
    PseudoObjectExprBits.NumSubExprs = semantics.size() + 1;
    PseudoObjectExprBits.ResultIndex = resultIndex + 1;
  
    for (unsigned i = 0, e = semantics.size() + 1; i != e; ++i) {
      Expr *E = (i == 0 ? syntax : semantics[i-1]);
      getSubExprsBuffer()[i] = E;
  
      if (E->isTypeDependent())
        ExprBits.TypeDependent = true;
      if (E->isValueDependent())
        ExprBits.ValueDependent = true;
      if (E->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (E->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
  
      if (isa<OpaqueValueExpr>(E))
        assert(cast<OpaqueValueExpr>(E)->getSourceExpr() != nullptr &&
               "opaque-value semantic expressions for pseudo-object "
               "operations must have sources");
    }
  }
  
  //===----------------------------------------------------------------------===//
  //  Child Iterators for iterating over subexpressions/substatements
  //===----------------------------------------------------------------------===//
  
  // UnaryExprOrTypeTraitExpr
  Stmt::child_range UnaryExprOrTypeTraitExpr::children() {
    const_child_range CCR =
        const_cast<const UnaryExprOrTypeTraitExpr *>(this)->children();
    return child_range(cast_away_const(CCR.begin()), cast_away_const(CCR.end()));
  }
  
  Stmt::const_child_range UnaryExprOrTypeTraitExpr::children() const {
    // If this is of a type and the type is a VLA type (and not a typedef), the
    // size expression of the VLA needs to be treated as an executable expression.
    // Why isn't this weirdness documented better in StmtIterator?
    if (isArgumentType()) {
      if (const VariableArrayType *T =
              dyn_cast<VariableArrayType>(getArgumentType().getTypePtr()))
        return const_child_range(const_child_iterator(T), const_child_iterator());
      return const_child_range(const_child_iterator(), const_child_iterator());
    }
    return const_child_range(&Argument.Ex, &Argument.Ex + 1);
  }
  
  AtomicExpr::AtomicExpr(SourceLocation BLoc, ArrayRef<Expr*> args,
                         QualType t, AtomicOp op, SourceLocation RP)
    : Expr(AtomicExprClass, t, VK_RValue, OK_Ordinary,
           false, false, false, false),
      NumSubExprs(args.size()), BuiltinLoc(BLoc), RParenLoc(RP), Op(op)
  {
    assert(args.size() == getNumSubExprs(op) && "wrong number of subexpressions");
    for (unsigned i = 0; i != args.size(); i++) {
      if (args[i]->isTypeDependent())
        ExprBits.TypeDependent = true;
      if (args[i]->isValueDependent())
        ExprBits.ValueDependent = true;
      if (args[i]->isInstantiationDependent())
        ExprBits.InstantiationDependent = true;
      if (args[i]->containsUnexpandedParameterPack())
        ExprBits.ContainsUnexpandedParameterPack = true;
  
      SubExprs[i] = args[i];
    }
  }
  
  unsigned AtomicExpr::getNumSubExprs(AtomicOp Op) {
    switch (Op) {
    case AO__c11_atomic_init:
    case AO__opencl_atomic_init:
    case AO__c11_atomic_load:
    case AO__atomic_load_n:
      return 2;
  
    case AO__opencl_atomic_load:
    case AO__c11_atomic_store:
    case AO__c11_atomic_exchange:
    case AO__atomic_load:
    case AO__atomic_store:
    case AO__atomic_store_n:
    case AO__atomic_exchange_n:
    case AO__c11_atomic_fetch_add:
    case AO__c11_atomic_fetch_sub:
    case AO__c11_atomic_fetch_and:
    case AO__c11_atomic_fetch_or:
    case AO__c11_atomic_fetch_xor:
    case AO__atomic_fetch_add:
    case AO__atomic_fetch_sub:
    case AO__atomic_fetch_and:
    case AO__atomic_fetch_or:
    case AO__atomic_fetch_xor:
    case AO__atomic_fetch_nand:
    case AO__atomic_add_fetch:
    case AO__atomic_sub_fetch:
    case AO__atomic_and_fetch:
    case AO__atomic_or_fetch:
    case AO__atomic_xor_fetch:
    case AO__atomic_nand_fetch:
    case AO__atomic_fetch_min:
    case AO__atomic_fetch_max:
      return 3;
  
    case AO__opencl_atomic_store:
    case AO__opencl_atomic_exchange:
    case AO__opencl_atomic_fetch_add:
    case AO__opencl_atomic_fetch_sub:
    case AO__opencl_atomic_fetch_and:
    case AO__opencl_atomic_fetch_or:
    case AO__opencl_atomic_fetch_xor:
    case AO__opencl_atomic_fetch_min:
    case AO__opencl_atomic_fetch_max:
    case AO__atomic_exchange:
      return 4;
  
    case AO__c11_atomic_compare_exchange_strong:
    case AO__c11_atomic_compare_exchange_weak:
      return 5;
  
    case AO__opencl_atomic_compare_exchange_strong:
    case AO__opencl_atomic_compare_exchange_weak:
    case AO__atomic_compare_exchange:
    case AO__atomic_compare_exchange_n:
      return 6;
    }
    llvm_unreachable("unknown atomic op");
  }
  
  QualType AtomicExpr::getValueType() const {
    auto T = getPtr()->getType()->castAs<PointerType>()->getPointeeType();
    if (auto AT = T->getAs<AtomicType>())
      return AT->getValueType();
    return T;
  }
  
  QualType OMPArraySectionExpr::getBaseOriginalType(const Expr *Base) {
    unsigned ArraySectionCount = 0;
    while (auto *OASE = dyn_cast<OMPArraySectionExpr>(Base->IgnoreParens())) {
      Base = OASE->getBase();
      ++ArraySectionCount;
    }
    while (auto *ASE =
               dyn_cast<ArraySubscriptExpr>(Base->IgnoreParenImpCasts())) {
      Base = ASE->getBase();
      ++ArraySectionCount;
    }
    Base = Base->IgnoreParenImpCasts();
    auto OriginalTy = Base->getType();
    if (auto *DRE = dyn_cast<DeclRefExpr>(Base))
      if (auto *PVD = dyn_cast<ParmVarDecl>(DRE->getDecl()))
        OriginalTy = PVD->getOriginalType().getNonReferenceType();
  
    for (unsigned Cnt = 0; Cnt < ArraySectionCount; ++Cnt) {
      if (OriginalTy->isAnyPointerType())
        OriginalTy = OriginalTy->getPointeeType();
      else {
        assert (OriginalTy->isArrayType());
        OriginalTy = OriginalTy->castAsArrayTypeUnsafe()->getElementType();
      }
    }
    return OriginalTy;
  }
  