EIC code displayed by LXR master/​include/​clang/​AST/​Expr.h	Source navigation Diff markup Identifier search General search
	Version: master test Revert   Change

File indexing completed on 2026-05-10 08:36:35

 //===--- Expr.h - Classes for representing expressions ----------*- C++ -*-===//
 //
 // 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 defines the Expr interface and subclasses.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_AST_EXPR_H
 #define LLVM_CLANG_AST_EXPR_H
 
 #include "clang/AST/APNumericStorage.h"
 #include "clang/AST/APValue.h"
 #include "clang/AST/ASTVector.h"
 #include "clang/AST/ComputeDependence.h"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclAccessPair.h"
 #include "clang/AST/DependenceFlags.h"
 #include "clang/AST/OperationKinds.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/TemplateBase.h"
 #include "clang/AST/Type.h"
 #include "clang/Basic/CharInfo.h"
 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SyncScope.h"
 #include "clang/Basic/TypeTraits.h"
 #include "llvm/ADT/APFloat.h"
 #include "llvm/ADT/APSInt.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/AtomicOrdering.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/TrailingObjects.h"
 #include <optional>
 
 namespace clang {
   class APValue;
   class ASTContext;
   class BlockDecl;
   class CXXBaseSpecifier;
   class CXXMemberCallExpr;
   class CXXOperatorCallExpr;
   class CastExpr;
   class Decl;
   class IdentifierInfo;
   class MaterializeTemporaryExpr;
   class NamedDecl;
   class ObjCPropertyRefExpr;
   class OpaqueValueExpr;
   class ParmVarDecl;
   class StringLiteral;
   class TargetInfo;
   class ValueDecl;
 
 /// A simple array of base specifiers.
 typedef SmallVector<CXXBaseSpecifier*, 4> CXXCastPath;
 
 /// An adjustment to be made to the temporary created when emitting a
 /// reference binding, which accesses a particular subobject of that temporary.
 struct SubobjectAdjustment {
   enum {
     DerivedToBaseAdjustment,
     FieldAdjustment,
     MemberPointerAdjustment
   } Kind;
 
   struct DTB {
     const CastExpr *BasePath;
     const CXXRecordDecl *DerivedClass;
   };
 
   struct P {
     const MemberPointerType *MPT;
     Expr *RHS;
   };
 
   union {
     struct DTB DerivedToBase;
     const FieldDecl *Field;
     struct P Ptr;
   };
 
   SubobjectAdjustment(const CastExpr *BasePath,
                       const CXXRecordDecl *DerivedClass)
     : Kind(DerivedToBaseAdjustment) {
     DerivedToBase.BasePath = BasePath;
     DerivedToBase.DerivedClass = DerivedClass;
   }
 
   SubobjectAdjustment(const FieldDecl *Field) : Kind(FieldAdjustment) {
     this->Field = Field;
   }
 
   SubobjectAdjustment(const MemberPointerType *MPT, Expr *RHS)
     : Kind(MemberPointerAdjustment) {
     this->Ptr.MPT = MPT;
     this->Ptr.RHS = RHS;
   }
 };
 
 /// This represents one expression.  Note that Expr's are subclasses of Stmt.
 /// This allows an expression to be transparently used any place a Stmt is
 /// required.
 class Expr : public ValueStmt {
   QualType TR;
 
 public:
   Expr() = delete;
   Expr(const Expr&) = delete;
   Expr(Expr &&) = delete;
   Expr &operator=(const Expr&) = delete;
   Expr &operator=(Expr&&) = delete;
 
 protected:
   Expr(StmtClass SC, QualType T, ExprValueKind VK, ExprObjectKind OK)
       : ValueStmt(SC) {
     ExprBits.Dependent = 0;
     ExprBits.ValueKind = VK;
     ExprBits.ObjectKind = OK;
     assert(ExprBits.ObjectKind == OK && "truncated kind");
     setType(T);
   }
 
   /// Construct an empty expression.
   explicit Expr(StmtClass SC, EmptyShell) : ValueStmt(SC) { }
 
   /// Each concrete expr subclass is expected to compute its dependence and call
   /// this in the constructor.
   void setDependence(ExprDependence Deps) {
     ExprBits.Dependent = static_cast<unsigned>(Deps);
   }
   friend class ASTImporter;   // Sets dependence directly.
   friend class ASTStmtReader; // Sets dependence directly.
 
 public:
   QualType getType() const { return TR; }
   void setType(QualType t) {
     // In C++, the type of an expression is always adjusted so that it
     // will not have reference type (C++ [expr]p6). Use
     // QualType::getNonReferenceType() to retrieve the non-reference
     // type. Additionally, inspect Expr::isLvalue to determine whether
     // an expression that is adjusted in this manner should be
     // considered an lvalue.
     assert((t.isNull() || !t->isReferenceType()) &&
            "Expressions can't have reference type");
 
     TR = t;
   }
 
   /// If this expression is an enumeration constant, return the
   /// enumeration type under which said constant was declared.
   /// Otherwise return the expression's type.
   /// Note this effectively circumvents the weak typing of C's enum constants
   QualType getEnumCoercedType(const ASTContext &Ctx) const;
 
   ExprDependence getDependence() const {
     return static_cast<ExprDependence>(ExprBits.Dependent);
   }
 
   /// Determines whether the value of this expression depends on
   ///   - a template parameter (C++ [temp.dep.constexpr])
   ///   - or an error, whose resolution is unknown
   ///
   /// For example, the array bound of "Chars" in the following example is
   /// value-dependent.
   /// @code
   /// template<int Size, char (&Chars)[Size]> struct meta_string;
   /// @endcode
   bool isValueDependent() const {
     return static_cast<bool>(getDependence() & ExprDependence::Value);
   }
 
   /// Determines whether the type of this expression depends on
   ///   - a template parameter (C++ [temp.dep.expr], which means that its type
   ///     could change from one template instantiation to the next)
   ///   - or an error
   ///
   /// For example, the expressions "x" and "x + y" are type-dependent in
   /// the following code, but "y" is not type-dependent:
   /// @code
   /// template<typename T>
   /// void add(T x, int y) {
   ///   x + y;
   /// }
   /// @endcode
   bool isTypeDependent() const {
     return static_cast<bool>(getDependence() & ExprDependence::Type);
   }
 
   /// Whether this expression is instantiation-dependent, meaning that
   /// it depends in some way on
   ///    - a template parameter (even if neither its type nor (constant) value
   ///      can change due to the template instantiation)
   ///    - or an error
   ///
   /// In the following example, the expression \c sizeof(sizeof(T() + T())) is
   /// instantiation-dependent (since it involves a template parameter \c T), but
   /// is neither type- nor value-dependent, since the type of the inner
   /// \c sizeof is known (\c std::size_t) and therefore the size of the outer
   /// \c sizeof is known.
   ///
   /// \code
   /// template<typename T>
   /// void f(T x, T y) {
   ///   sizeof(sizeof(T() + T());
   /// }
   /// \endcode
   ///
   /// \code
   /// void func(int) {
   ///   func(); // the expression is instantiation-dependent, because it depends
   ///           // on an error.
   /// }
   /// \endcode
   bool isInstantiationDependent() const {
     return static_cast<bool>(getDependence() & ExprDependence::Instantiation);
   }
 
   /// Whether this expression contains an unexpanded parameter
   /// pack (for C++11 variadic templates).
   ///
   /// Given the following function template:
   ///
   /// \code
   /// template<typename F, typename ...Types>
   /// void forward(const F &f, Types &&...args) {
   ///   f(static_cast<Types&&>(args)...);
   /// }
   /// \endcode
   ///
   /// The expressions \c args and \c static_cast<Types&&>(args) both
   /// contain parameter packs.
   bool containsUnexpandedParameterPack() const {
     return static_cast<bool>(getDependence() & ExprDependence::UnexpandedPack);
   }
 
   /// Whether this expression contains subexpressions which had errors, e.g. a
   /// TypoExpr.
   bool containsErrors() const {
     return static_cast<bool>(getDependence() & ExprDependence::Error);
   }
 
   /// getExprLoc - Return the preferred location for the arrow when diagnosing
   /// a problem with a generic expression.
   SourceLocation getExprLoc() const LLVM_READONLY;
 
   /// Determine whether an lvalue-to-rvalue conversion should implicitly be
   /// applied to this expression if it appears as a discarded-value expression
   /// in C++11 onwards. This applies to certain forms of volatile glvalues.
   bool isReadIfDiscardedInCPlusPlus11() const;
 
   /// isUnusedResultAWarning - Return true if this immediate expression should
   /// be warned about if the result is unused.  If so, fill in expr, location,
   /// and ranges with expr to warn on and source locations/ranges appropriate
   /// for a warning.
   bool isUnusedResultAWarning(const Expr *&WarnExpr, SourceLocation &Loc,
                               SourceRange &R1, SourceRange &R2,
                               ASTContext &Ctx) const;
 
   /// isLValue - True if this expression is an "l-value" according to
   /// the rules of the current language.  C and C++ give somewhat
   /// different rules for this concept, but in general, the result of
   /// an l-value expression identifies a specific object whereas the
   /// result of an r-value expression is a value detached from any
   /// specific storage.
   ///
   /// C++11 divides the concept of "r-value" into pure r-values
   /// ("pr-values") and so-called expiring values ("x-values"), which
   /// identify specific objects that can be safely cannibalized for
   /// their resources.
   bool isLValue() const { return getValueKind() == VK_LValue; }
   bool isPRValue() const { return getValueKind() == VK_PRValue; }
   bool isXValue() const { return getValueKind() == VK_XValue; }
   bool isGLValue() const { return getValueKind() != VK_PRValue; }
 
   enum LValueClassification {
     LV_Valid,
     LV_NotObjectType,
     LV_IncompleteVoidType,
     LV_DuplicateVectorComponents,
     LV_InvalidExpression,
     LV_InvalidMessageExpression,
     LV_MemberFunction,
     LV_SubObjCPropertySetting,
     LV_ClassTemporary,
     LV_ArrayTemporary
   };
   /// Reasons why an expression might not be an l-value.
   LValueClassification ClassifyLValue(ASTContext &Ctx) const;
 
   enum isModifiableLvalueResult {
     MLV_Valid,
     MLV_NotObjectType,
     MLV_IncompleteVoidType,
     MLV_DuplicateVectorComponents,
     MLV_InvalidExpression,
     MLV_LValueCast,           // Specialized form of MLV_InvalidExpression.
     MLV_IncompleteType,
     MLV_ConstQualified,
     MLV_ConstQualifiedField,
     MLV_ConstAddrSpace,
     MLV_ArrayType,
     MLV_NoSetterProperty,
     MLV_MemberFunction,
     MLV_SubObjCPropertySetting,
     MLV_InvalidMessageExpression,
     MLV_ClassTemporary,
     MLV_ArrayTemporary
   };
   /// isModifiableLvalue - C99 6.3.2.1: an lvalue that does not have array type,
   /// does not have an incomplete type, does not have a const-qualified type,
   /// and if it is a structure or union, does not have any member (including,
   /// recursively, any member or element of all contained aggregates or unions)
   /// with a const-qualified type.
   ///
   /// \param Loc [in,out] - A source location which *may* be filled
   /// in with the location of the expression making this a
   /// non-modifiable lvalue, if specified.
   isModifiableLvalueResult
   isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc = nullptr) const;
 
   /// The return type of classify(). Represents the C++11 expression
   ///        taxonomy.
   class Classification {
   public:
     /// The various classification results. Most of these mean prvalue.
     enum Kinds {
       CL_LValue,
       CL_XValue,
       CL_Function, // Functions cannot be lvalues in C.
       CL_Void, // Void cannot be an lvalue in C.
       CL_AddressableVoid, // Void expression whose address can be taken in C.
       CL_DuplicateVectorComponents, // A vector shuffle with dupes.
       CL_MemberFunction, // An expression referring to a member function
       CL_SubObjCPropertySetting,
       CL_ClassTemporary, // A temporary of class type, or subobject thereof.
       CL_ArrayTemporary, // A temporary of array type.
       CL_ObjCMessageRValue, // ObjC message is an rvalue
       CL_PRValue // A prvalue for any other reason, of any other type
     };
     /// The results of modification testing.
     enum ModifiableType {
       CM_Untested, // testModifiable was false.
       CM_Modifiable,
       CM_RValue, // Not modifiable because it's an rvalue
       CM_Function, // Not modifiable because it's a function; C++ only
       CM_LValueCast, // Same as CM_RValue, but indicates GCC cast-as-lvalue ext
       CM_NoSetterProperty,// Implicit assignment to ObjC property without setter
       CM_ConstQualified,
       CM_ConstQualifiedField,
       CM_ConstAddrSpace,
       CM_ArrayType,
       CM_IncompleteType
     };
 
   private:
     friend class Expr;
 
     unsigned short Kind;
     unsigned short Modifiable;
 
     explicit Classification(Kinds k, ModifiableType m)
       : Kind(k), Modifiable(m)
     {}
 
   public:
     Classification() {}
 
     Kinds getKind() const { return static_cast<Kinds>(Kind); }
     ModifiableType getModifiable() const {
       assert(Modifiable != CM_Untested && "Did not test for modifiability.");
       return static_cast<ModifiableType>(Modifiable);
     }
     bool isLValue() const { return Kind == CL_LValue; }
     bool isXValue() const { return Kind == CL_XValue; }
     bool isGLValue() const { return Kind <= CL_XValue; }
     bool isPRValue() const { return Kind >= CL_Function; }
     bool isRValue() const { return Kind >= CL_XValue; }
     bool isModifiable() const { return getModifiable() == CM_Modifiable; }
 
     /// Create a simple, modifiable lvalue
     static Classification makeSimpleLValue() {
       return Classification(CL_LValue, CM_Modifiable);
     }
 
   };
   /// Classify - Classify this expression according to the C++11
   ///        expression taxonomy.
   ///
   /// C++11 defines ([basic.lval]) a new taxonomy of expressions to replace the
   /// old lvalue vs rvalue. This function determines the type of expression this
   /// is. There are three expression types:
   /// - lvalues are classical lvalues as in C++03.
   /// - prvalues are equivalent to rvalues in C++03.
   /// - xvalues are expressions yielding unnamed rvalue references, e.g. a
   ///   function returning an rvalue reference.
   /// lvalues and xvalues are collectively referred to as glvalues, while
   /// prvalues and xvalues together form rvalues.
   Classification Classify(ASTContext &Ctx) const {
     return ClassifyImpl(Ctx, nullptr);
   }
 
   /// ClassifyModifiable - Classify this expression according to the
   ///        C++11 expression taxonomy, and see if it is valid on the left side
   ///        of an assignment.
   ///
   /// This function extends classify in that it also tests whether the
   /// expression is modifiable (C99 6.3.2.1p1).
   /// \param Loc A source location that might be filled with a relevant location
   ///            if the expression is not modifiable.
   Classification ClassifyModifiable(ASTContext &Ctx, SourceLocation &Loc) const{
     return ClassifyImpl(Ctx, &Loc);
   }
 
   /// Returns the set of floating point options that apply to this expression.
   /// Only meaningful for operations on floating point values.
   FPOptions getFPFeaturesInEffect(const LangOptions &LO) const;
 
   /// getValueKindForType - Given a formal return or parameter type,
   /// give its value kind.
   static ExprValueKind getValueKindForType(QualType T) {
     if (const ReferenceType *RT = T->getAs<ReferenceType>())
       return (isa<LValueReferenceType>(RT)
                 ? VK_LValue
                 : (RT->getPointeeType()->isFunctionType()
                      ? VK_LValue : VK_XValue));
     return VK_PRValue;
   }
 
   /// getValueKind - The value kind that this expression produces.
   ExprValueKind getValueKind() const {
     return static_cast<ExprValueKind>(ExprBits.ValueKind);
   }
 
   /// getObjectKind - The object kind that this expression produces.
   /// Object kinds are meaningful only for expressions that yield an
   /// l-value or x-value.
   ExprObjectKind getObjectKind() const {
     return static_cast<ExprObjectKind>(ExprBits.ObjectKind);
   }
 
   bool isOrdinaryOrBitFieldObject() const {
     ExprObjectKind OK = getObjectKind();
     return (OK == OK_Ordinary || OK == OK_BitField);
   }
 
   /// setValueKind - Set the value kind produced by this expression.
   void setValueKind(ExprValueKind Cat) { ExprBits.ValueKind = Cat; }
 
   /// setObjectKind - Set the object kind produced by this expression.
   void setObjectKind(ExprObjectKind Cat) { ExprBits.ObjectKind = Cat; }
 
 private:
   Classification ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const;
 
 public:
 
   /// Returns true if this expression is a gl-value that
   /// potentially refers to a bit-field.
   ///
   /// In C++, whether a gl-value refers to a bitfield is essentially
   /// an aspect of the value-kind type system.
   bool refersToBitField() const { return getObjectKind() == OK_BitField; }
 
   /// If this expression refers to a bit-field, retrieve the
   /// declaration of that bit-field.
   ///
   /// Note that this returns a non-null pointer in subtly different
   /// places than refersToBitField returns true.  In particular, this can
   /// return a non-null pointer even for r-values loaded from
   /// bit-fields, but it will return null for a conditional bit-field.
   FieldDecl *getSourceBitField();
 
   /// If this expression refers to an enum constant, retrieve its declaration
   EnumConstantDecl *getEnumConstantDecl();
 
   const EnumConstantDecl *getEnumConstantDecl() const {
     return const_cast<Expr *>(this)->getEnumConstantDecl();
   }
 
   const FieldDecl *getSourceBitField() const {
     return const_cast<Expr*>(this)->getSourceBitField();
   }
 
   Decl *getReferencedDeclOfCallee();
   const Decl *getReferencedDeclOfCallee() const {
     return const_cast<Expr*>(this)->getReferencedDeclOfCallee();
   }
 
   /// If this expression is an l-value for an Objective C
   /// property, find the underlying property reference expression.
   const ObjCPropertyRefExpr *getObjCProperty() const;
 
   /// Check if this expression is the ObjC 'self' implicit parameter.
   bool isObjCSelfExpr() const;
 
   /// Returns whether this expression refers to a vector element.
   bool refersToVectorElement() const;
 
   /// Returns whether this expression refers to a matrix element.
   bool refersToMatrixElement() const {
     return getObjectKind() == OK_MatrixComponent;
   }
 
   /// Returns whether this expression refers to a global register
   /// variable.
   bool refersToGlobalRegisterVar() const;
 
   /// Returns whether this expression has a placeholder type.
   bool hasPlaceholderType() const {
     return getType()->isPlaceholderType();
   }
 
   /// Returns whether this expression has a specific placeholder type.
   bool hasPlaceholderType(BuiltinType::Kind K) const {
     assert(BuiltinType::isPlaceholderTypeKind(K));
     if (const BuiltinType *BT = dyn_cast<BuiltinType>(getType()))
       return BT->getKind() == K;
     return false;
   }
 
   /// 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.
   ///
   /// \param Semantic If true, only return true for expressions that are known
   /// to be semantically boolean, which might not be true even for expressions
   /// that are known to evaluate to 0/1. For instance, reading an unsigned
   /// bit-field with width '1' will evaluate to 0/1, but doesn't necessarily
   /// semantically correspond to a bool.
   bool isKnownToHaveBooleanValue(bool Semantic = true) const;
 
   /// Check whether this array fits the idiom of a flexible array member,
   /// depending on the value of -fstrict-flex-array.
   /// When IgnoreTemplateOrMacroSubstitution is set, it doesn't consider sizes
   /// resulting from the substitution of a macro or a template as special sizes.
   bool isFlexibleArrayMemberLike(
       ASTContext &Context,
       LangOptions::StrictFlexArraysLevelKind StrictFlexArraysLevel,
       bool IgnoreTemplateOrMacroSubstitution = false) const;
 
   /// isIntegerConstantExpr - Return the value if this expression is a valid
   /// integer constant expression.  If not a valid i-c-e, return std::nullopt
   /// and fill in Loc (if specified) with the location of the invalid
   /// expression.
   ///
   /// Note: This does not perform the implicit conversions required by C++11
   /// [expr.const]p5.
   std::optional<llvm::APSInt>
   getIntegerConstantExpr(const ASTContext &Ctx,
                          SourceLocation *Loc = nullptr) const;
   bool isIntegerConstantExpr(const ASTContext &Ctx,
                              SourceLocation *Loc = nullptr) const;
 
   /// isCXX98IntegralConstantExpr - Return true if this expression is an
   /// integral constant expression in C++98. Can only be used in C++.
   bool isCXX98IntegralConstantExpr(const ASTContext &Ctx) const;
 
   /// isCXX11ConstantExpr - Return true if this expression is a constant
   /// expression in C++11. Can only be used in C++.
   ///
   /// Note: This does not perform the implicit conversions required by C++11
   /// [expr.const]p5.
   bool isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result = nullptr,
                            SourceLocation *Loc = nullptr) const;
 
   /// isPotentialConstantExpr - Return true if this function's definition
   /// might be usable in a constant expression in C++11, if it were marked
   /// constexpr. Return false if the function can never produce a constant
   /// expression, along with diagnostics describing why not.
   static bool isPotentialConstantExpr(const FunctionDecl *FD,
                                       SmallVectorImpl<
                                         PartialDiagnosticAt> &Diags);
 
   /// isPotentialConstantExprUnevaluated - Return true if this expression might
   /// be usable in a constant expression in C++11 in an unevaluated context, if
   /// it were in function FD marked constexpr. Return false if the function can
   /// never produce a constant expression, along with diagnostics describing
   /// why not.
   static bool isPotentialConstantExprUnevaluated(Expr *E,
                                                  const FunctionDecl *FD,
                                                  SmallVectorImpl<
                                                    PartialDiagnosticAt> &Diags);
 
   /// isConstantInitializer - Returns true if this expression can be emitted to
   /// IR as a constant, and thus can be used as a constant initializer in C.
   /// If this expression is not constant and Culprit is non-null,
   /// it is used to store the address of first non constant expr.
   bool isConstantInitializer(ASTContext &Ctx, bool ForRef,
                              const Expr **Culprit = nullptr) const;
 
   /// If this expression is an unambiguous reference to a single declaration,
   /// in the style of __builtin_function_start, return that declaration.  Note
   /// that this may return a non-static member function or field in C++ if this
   /// expression is a member pointer constant.
   const ValueDecl *getAsBuiltinConstantDeclRef(const ASTContext &Context) const;
 
   /// EvalStatus is a struct with detailed info about an evaluation in progress.
   struct EvalStatus {
     /// Whether the evaluated expression has side effects.
     /// For example, (f() && 0) can be folded, but it still has side effects.
     bool HasSideEffects = false;
 
     /// Whether the evaluation hit undefined behavior.
     /// For example, 1.0 / 0.0 can be folded to Inf, but has undefined behavior.
     /// Likewise, INT_MAX + 1 can be folded to INT_MIN, but has UB.
     bool HasUndefinedBehavior = false;
 
     /// Diag - If this is non-null, it will be filled in with a stack of notes
     /// indicating why evaluation failed (or why it failed to produce a constant
     /// expression).
     /// If the expression is unfoldable, the notes will indicate why it's not
     /// foldable. If the expression is foldable, but not a constant expression,
     /// the notes will describes why it isn't a constant expression. If the
     /// expression *is* a constant expression, no notes will be produced.
     ///
     /// FIXME: this causes significant performance concerns and should be
     /// refactored at some point. Not all evaluations of the constant
     /// expression interpreter will display the given diagnostics, this means
     /// those kinds of uses are paying the expense of generating a diagnostic
     /// (which may include expensive operations like converting APValue objects
     /// to a string representation).
     SmallVectorImpl<PartialDiagnosticAt> *Diag = nullptr;
 
     EvalStatus() = default;
 
     // hasSideEffects - Return true if the evaluated expression has
     // side effects.
     bool hasSideEffects() const {
       return HasSideEffects;
     }
   };
 
   /// EvalResult is a struct with detailed info about an evaluated expression.
   struct EvalResult : EvalStatus {
     /// Val - This is the value the expression can be folded to.
     APValue Val;
 
     // isGlobalLValue - Return true if the evaluated lvalue expression
     // is global.
     bool isGlobalLValue() const;
   };
 
   /// EvaluateAsRValue - Return true if this is a constant which we can fold to
   /// an rvalue using any crazy technique (that has nothing to do with language
   /// standards) that we want to, even if the expression has side-effects. If
   /// this function returns true, it returns the folded constant in Result. If
   /// the expression is a glvalue, an lvalue-to-rvalue conversion will be
   /// applied.
   bool EvaluateAsRValue(EvalResult &Result, const ASTContext &Ctx,
                         bool InConstantContext = false) const;
 
   /// EvaluateAsBooleanCondition - Return true if this is a constant
   /// which we can fold and convert to a boolean condition using
   /// any crazy technique that we want to, even if the expression has
   /// side-effects.
   bool EvaluateAsBooleanCondition(bool &Result, const ASTContext &Ctx,
                                   bool InConstantContext = false) const;
 
   enum SideEffectsKind {
     SE_NoSideEffects,          ///< Strictly evaluate the expression.
     SE_AllowUndefinedBehavior, ///< Allow UB that we can give a value, but not
                                ///< arbitrary unmodeled side effects.
     SE_AllowSideEffects        ///< Allow any unmodeled side effect.
   };
 
   /// EvaluateAsInt - Return true if this is a constant which we can fold and
   /// convert to an integer, using any crazy technique that we want to.
   bool EvaluateAsInt(EvalResult &Result, const ASTContext &Ctx,
                      SideEffectsKind AllowSideEffects = SE_NoSideEffects,
                      bool InConstantContext = false) const;
 
   /// EvaluateAsFloat - Return true if this is a constant which we can fold and
   /// convert to a floating point value, using any crazy technique that we
   /// want to.
   bool EvaluateAsFloat(llvm::APFloat &Result, const ASTContext &Ctx,
                        SideEffectsKind AllowSideEffects = SE_NoSideEffects,
                        bool InConstantContext = false) const;
 
   /// EvaluateAsFixedPoint - Return true if this is a constant which we can fold
   /// and convert to a fixed point value.
   bool EvaluateAsFixedPoint(EvalResult &Result, const ASTContext &Ctx,
                             SideEffectsKind AllowSideEffects = SE_NoSideEffects,
                             bool InConstantContext = false) const;
 
   /// isEvaluatable - Call EvaluateAsRValue to see if this expression can be
   /// constant folded without side-effects, but discard the result.
   bool isEvaluatable(const ASTContext &Ctx,
                      SideEffectsKind AllowSideEffects = SE_NoSideEffects) const;
 
   /// HasSideEffects - This routine returns true for all those expressions
   /// which have any effect other than producing a value. Example is a function
   /// call, volatile variable read, or throwing an exception. If
   /// IncludePossibleEffects is false, this call treats certain expressions with
   /// potential side effects (such as function call-like expressions,
   /// instantiation-dependent expressions, or invocations from a macro) as not
   /// having side effects.
   bool HasSideEffects(const ASTContext &Ctx,
                       bool IncludePossibleEffects = true) const;
 
   /// Determine whether this expression involves a call to any function
   /// that is not trivial.
   bool hasNonTrivialCall(const ASTContext &Ctx) const;
 
   /// EvaluateKnownConstInt - Call EvaluateAsRValue and return the folded
   /// integer. This must be called on an expression that constant folds to an
   /// integer.
   llvm::APSInt EvaluateKnownConstInt(
       const ASTContext &Ctx,
       SmallVectorImpl<PartialDiagnosticAt> *Diag = nullptr) const;
 
   llvm::APSInt EvaluateKnownConstIntCheckOverflow(
       const ASTContext &Ctx,
       SmallVectorImpl<PartialDiagnosticAt> *Diag = nullptr) const;
 
   void EvaluateForOverflow(const ASTContext &Ctx) const;
 
   /// EvaluateAsLValue - Evaluate an expression to see if we can fold it to an
   /// lvalue with link time known address, with no side-effects.
   bool EvaluateAsLValue(EvalResult &Result, const ASTContext &Ctx,
                         bool InConstantContext = false) const;
 
   /// EvaluateAsInitializer - Evaluate an expression as if it were the
   /// initializer of the given declaration. Returns true if the initializer
   /// can be folded to a constant, and produces any relevant notes. In C++11,
   /// notes will be produced if the expression is not a constant expression.
   bool EvaluateAsInitializer(APValue &Result, const ASTContext &Ctx,
                              const VarDecl *VD,
                              SmallVectorImpl<PartialDiagnosticAt> &Notes,
                              bool IsConstantInitializer) const;
 
   /// EvaluateWithSubstitution - Evaluate an expression as if from the context
   /// of a call to the given function with the given arguments, inside an
   /// unevaluated context. Returns true if the expression could be folded to a
   /// constant.
   bool EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
                                 const FunctionDecl *Callee,
                                 ArrayRef<const Expr*> Args,
                                 const Expr *This = nullptr) const;
 
   enum class ConstantExprKind {
     /// An integer constant expression (an array bound, enumerator, case value,
     /// bit-field width, or similar) or similar.
     Normal,
     /// A non-class template argument. Such a value is only used for mangling,
     /// not for code generation, so can refer to dllimported functions.
     NonClassTemplateArgument,
     /// A class template argument. Such a value is used for code generation.
     ClassTemplateArgument,
     /// An immediate invocation. The destruction of the end result of this
     /// evaluation is not part of the evaluation, but all other temporaries
     /// are destroyed.
     ImmediateInvocation,
   };
 
   /// Evaluate an expression that is required to be a constant expression. Does
   /// not check the syntactic constraints for C and C++98 constant expressions.
   bool EvaluateAsConstantExpr(
       EvalResult &Result, const ASTContext &Ctx,
       ConstantExprKind Kind = ConstantExprKind::Normal) const;
 
   /// If the current Expr is a pointer, this will try to statically
   /// determine the number of bytes available where the pointer is pointing.
   /// Returns true if all of the above holds and we were able to figure out the
   /// size, false otherwise.
   ///
   /// \param Type - How to evaluate the size of the Expr, as defined by the
   /// "type" parameter of __builtin_object_size
   bool tryEvaluateObjectSize(uint64_t &Result, ASTContext &Ctx,
                              unsigned Type) const;
 
   /// If the current Expr is a pointer, this will try to statically
   /// determine the strlen of the string pointed to.
   /// Returns true if all of the above holds and we were able to figure out the
   /// strlen, false otherwise.
   bool tryEvaluateStrLen(uint64_t &Result, ASTContext &Ctx) const;
 
   bool EvaluateCharRangeAsString(std::string &Result,
                                  const Expr *SizeExpression,
                                  const Expr *PtrExpression, ASTContext &Ctx,
                                  EvalResult &Status) const;
 
   /// If the current Expr can be evaluated to a pointer to a null-terminated
   /// constant string, return the constant string (without the terminating
   /// null).
   std::optional<std::string> tryEvaluateString(ASTContext &Ctx) const;
 
   /// Enumeration used to describe the kind of Null pointer constant
   /// returned from \c isNullPointerConstant().
   enum NullPointerConstantKind {
     /// Expression is not a Null pointer constant.
     NPCK_NotNull = 0,
 
     /// Expression is a Null pointer constant built from a zero integer
     /// expression that is not a simple, possibly parenthesized, zero literal.
     /// C++ Core Issue 903 will classify these expressions as "not pointers"
     /// once it is adopted.
     /// http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
     NPCK_ZeroExpression,
 
     /// Expression is a Null pointer constant built from a literal zero.
     NPCK_ZeroLiteral,
 
     /// Expression is a C++11 nullptr.
     NPCK_CXX11_nullptr,
 
     /// Expression is a GNU-style __null constant.
     NPCK_GNUNull
   };
 
   /// Enumeration used to describe how \c isNullPointerConstant()
   /// should cope with value-dependent expressions.
   enum NullPointerConstantValueDependence {
     /// Specifies that the expression should never be value-dependent.
     NPC_NeverValueDependent = 0,
 
     /// Specifies that a value-dependent expression of integral or
     /// dependent type should be considered a null pointer constant.
     NPC_ValueDependentIsNull,
 
     /// Specifies that a value-dependent expression should be considered
     /// to never be a null pointer constant.
     NPC_ValueDependentIsNotNull
   };
 
   /// isNullPointerConstant - C99 6.3.2.3p3 - Test if this reduces down to
   /// a Null pointer constant. The return value can further distinguish the
   /// kind of NULL pointer constant that was detected.
   NullPointerConstantKind isNullPointerConstant(
       ASTContext &Ctx,
       NullPointerConstantValueDependence NPC) const;
 
   /// isOBJCGCCandidate - Return true if this expression may be used in a read/
   /// write barrier.
   bool isOBJCGCCandidate(ASTContext &Ctx) const;
 
   /// Returns true if this expression is a bound member function.
   bool isBoundMemberFunction(ASTContext &Ctx) const;
 
   /// Given an expression of bound-member type, find the type
   /// of the member.  Returns null if this is an *overloaded* bound
   /// member expression.
   static QualType findBoundMemberType(const Expr *expr);
 
   /// Skip past any invisible AST nodes which might surround this
   /// statement, such as ExprWithCleanups or ImplicitCastExpr nodes,
   /// but also injected CXXMemberExpr and CXXConstructExpr which represent
   /// implicit conversions.
   Expr *IgnoreUnlessSpelledInSource();
   const Expr *IgnoreUnlessSpelledInSource() const {
     return const_cast<Expr *>(this)->IgnoreUnlessSpelledInSource();
   }
 
   /// Skip past any implicit casts which might surround this expression until
   /// reaching a fixed point. Skips:
   /// * ImplicitCastExpr
   /// * FullExpr
   Expr *IgnoreImpCasts() LLVM_READONLY;
   const Expr *IgnoreImpCasts() const {
     return const_cast<Expr *>(this)->IgnoreImpCasts();
   }
 
   /// Skip past any casts which might surround this expression until reaching
   /// a fixed point. Skips:
   /// * CastExpr
   /// * FullExpr
   /// * MaterializeTemporaryExpr
   /// * SubstNonTypeTemplateParmExpr
   Expr *IgnoreCasts() LLVM_READONLY;
   const Expr *IgnoreCasts() const {
     return const_cast<Expr *>(this)->IgnoreCasts();
   }
 
   /// Skip past any implicit AST nodes which might surround this expression
   /// until reaching a fixed point. Skips:
   /// * What IgnoreImpCasts() skips
   /// * MaterializeTemporaryExpr
   /// * CXXBindTemporaryExpr
   Expr *IgnoreImplicit() LLVM_READONLY;
   const Expr *IgnoreImplicit() const {
     return const_cast<Expr *>(this)->IgnoreImplicit();
   }
 
   /// Skip past any implicit AST nodes which might surround this expression
   /// until reaching a fixed point. Same as IgnoreImplicit, except that it
   /// also skips over implicit calls to constructors and conversion functions.
   ///
   /// FIXME: Should IgnoreImplicit do this?
   Expr *IgnoreImplicitAsWritten() LLVM_READONLY;
   const Expr *IgnoreImplicitAsWritten() const {
     return const_cast<Expr *>(this)->IgnoreImplicitAsWritten();
   }
 
   /// Skip past any parentheses which might surround this expression until
   /// reaching a fixed point. Skips:
   /// * ParenExpr
   /// * UnaryOperator if `UO_Extension`
   /// * GenericSelectionExpr if `!isResultDependent()`
   /// * ChooseExpr if `!isConditionDependent()`
   /// * ConstantExpr
   Expr *IgnoreParens() LLVM_READONLY;
   const Expr *IgnoreParens() const {
     return const_cast<Expr *>(this)->IgnoreParens();
   }
 
   /// Skip past any parentheses and implicit casts which might surround this
   /// expression until reaching a fixed point.
   /// FIXME: IgnoreParenImpCasts really ought to be equivalent to
   /// IgnoreParens() + IgnoreImpCasts() until reaching a fixed point. However
   /// this is currently not the case. Instead IgnoreParenImpCasts() skips:
   /// * What IgnoreParens() skips
   /// * What IgnoreImpCasts() skips
   /// * MaterializeTemporaryExpr
   /// * SubstNonTypeTemplateParmExpr
   Expr *IgnoreParenImpCasts() LLVM_READONLY;
   const Expr *IgnoreParenImpCasts() const {
     return const_cast<Expr *>(this)->IgnoreParenImpCasts();
   }
 
   /// Skip past any parentheses and casts which might surround this expression
   /// until reaching a fixed point. Skips:
   /// * What IgnoreParens() skips
   /// * What IgnoreCasts() skips
   Expr *IgnoreParenCasts() LLVM_READONLY;
   const Expr *IgnoreParenCasts() const {
     return const_cast<Expr *>(this)->IgnoreParenCasts();
   }
 
   /// Skip conversion operators. If this Expr is a call to a conversion
   /// operator, return the argument.
   Expr *IgnoreConversionOperatorSingleStep() LLVM_READONLY;
   const Expr *IgnoreConversionOperatorSingleStep() const {
     return const_cast<Expr *>(this)->IgnoreConversionOperatorSingleStep();
   }
 
   /// Skip past any parentheses and lvalue casts which might surround this
   /// expression until reaching a fixed point. Skips:
   /// * What IgnoreParens() skips
   /// * What IgnoreCasts() skips, except that only lvalue-to-rvalue
   ///   casts are skipped
   /// FIXME: This is intended purely as a temporary workaround for code
   /// that hasn't yet been rewritten to do the right thing about those
   /// casts, and may disappear along with the last internal use.
   Expr *IgnoreParenLValueCasts() LLVM_READONLY;
   const Expr *IgnoreParenLValueCasts() const {
     return const_cast<Expr *>(this)->IgnoreParenLValueCasts();
   }
 
   /// Skip past any parentheses and casts which do not change the value
   /// (including ptr->int casts of the same size) until reaching a fixed point.
   /// Skips:
   /// * What IgnoreParens() skips
   /// * CastExpr which do not change the value
   /// * SubstNonTypeTemplateParmExpr
   Expr *IgnoreParenNoopCasts(const ASTContext &Ctx) LLVM_READONLY;
   const Expr *IgnoreParenNoopCasts(const ASTContext &Ctx) const {
     return const_cast<Expr *>(this)->IgnoreParenNoopCasts(Ctx);
   }
 
   /// Skip past any parentheses and derived-to-base casts until reaching a
   /// fixed point. Skips:
   /// * What IgnoreParens() skips
   /// * CastExpr which represent a derived-to-base cast (CK_DerivedToBase,
   ///   CK_UncheckedDerivedToBase and CK_NoOp)
   Expr *IgnoreParenBaseCasts() LLVM_READONLY;
   const Expr *IgnoreParenBaseCasts() const {
     return const_cast<Expr *>(this)->IgnoreParenBaseCasts();
   }
 
   /// Determine whether this expression is a default function argument.
   ///
   /// Default arguments are implicitly generated in the abstract syntax tree
   /// by semantic analysis for function calls, object constructions, etc. in
   /// C++. Default arguments are represented by \c CXXDefaultArgExpr nodes;
   /// this routine also looks through any implicit casts to determine whether
   /// the expression is a default argument.
   bool isDefaultArgument() const;
 
   /// Determine whether the result of this expression is a
   /// temporary object of the given class type.
   bool isTemporaryObject(ASTContext &Ctx, const CXXRecordDecl *TempTy) const;
 
   /// Whether this expression is an implicit reference to 'this' in C++.
   bool isImplicitCXXThis() const;
 
   static bool hasAnyTypeDependentArguments(ArrayRef<Expr *> Exprs);
 
   /// For an expression of class type or pointer to class type,
   /// return the most derived class decl the expression is known to refer to.
   ///
   /// If this expression is a cast, this method looks through it to find the
   /// most derived decl that can be inferred from the expression.
   /// This is valid because derived-to-base conversions have undefined
   /// behavior if the object isn't dynamically of the derived type.
   const CXXRecordDecl *getBestDynamicClassType() const;
 
   /// Get the inner expression that determines the best dynamic class.
   /// If this is a prvalue, we guarantee that it is of the most-derived type
   /// for the object itself.
   const Expr *getBestDynamicClassTypeExpr() const;
 
   /// Walk outwards from an expression we want to bind a reference to and
   /// find the expression whose lifetime needs to be extended. Record
   /// the LHSs of comma expressions and adjustments needed along the path.
   const Expr *skipRValueSubobjectAdjustments(
       SmallVectorImpl<const Expr *> &CommaLHS,
       SmallVectorImpl<SubobjectAdjustment> &Adjustments) const;
   const Expr *skipRValueSubobjectAdjustments() const {
     SmallVector<const Expr *, 8> CommaLHSs;
     SmallVector<SubobjectAdjustment, 8> Adjustments;
     return skipRValueSubobjectAdjustments(CommaLHSs, Adjustments);
   }
 
   /// Checks that the two Expr's will refer to the same value as a comparison
   /// operand.  The caller must ensure that the values referenced by the Expr's
   /// are not modified between E1 and E2 or the result my be invalid.
   static bool isSameComparisonOperand(const Expr* E1, const Expr* E2);
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() >= firstExprConstant &&
            T->getStmtClass() <= lastExprConstant;
   }
 };
 // PointerLikeTypeTraits is specialized so it can be used with a forward-decl of
 // Expr. Verify that we got it right.
 static_assert(llvm::PointerLikeTypeTraits<Expr *>::NumLowBitsAvailable <=
                   llvm::detail::ConstantLog2<alignof(Expr)>::value,
               "PointerLikeTypeTraits<Expr*> assumes too much alignment.");
 
 using ConstantExprKind = Expr::ConstantExprKind;
 
 //===----------------------------------------------------------------------===//
 // Wrapper Expressions.
 //===----------------------------------------------------------------------===//
 
 /// FullExpr - Represents a "full-expression" node.
 class FullExpr : public Expr {
 protected:
  Stmt *SubExpr;
 
  FullExpr(StmtClass SC, Expr *subexpr)
      : Expr(SC, subexpr->getType(), subexpr->getValueKind(),
             subexpr->getObjectKind()),
        SubExpr(subexpr) {
    setDependence(computeDependence(this));
  }
   FullExpr(StmtClass SC, EmptyShell Empty)
     : Expr(SC, Empty) {}
 public:
   const Expr *getSubExpr() const { return cast<Expr>(SubExpr); }
   Expr *getSubExpr() { return cast<Expr>(SubExpr); }
 
   /// As with any mutator of the AST, be very careful when modifying an
   /// existing AST to preserve its invariants.
   void setSubExpr(Expr *E) { SubExpr = E; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() >= firstFullExprConstant &&
            T->getStmtClass() <= lastFullExprConstant;
   }
 };
 
 /// Describes the kind of result that can be tail-allocated.
 enum class ConstantResultStorageKind { None, Int64, APValue };
 
 /// ConstantExpr - An expression that occurs in a constant context and
 /// optionally the result of evaluating the expression.
 class ConstantExpr final
     : public FullExpr,
       private llvm::TrailingObjects<ConstantExpr, APValue, uint64_t> {
   static_assert(std::is_same<uint64_t, llvm::APInt::WordType>::value,
                 "ConstantExpr assumes that llvm::APInt::WordType is uint64_t "
                 "for tail-allocated storage");
   friend TrailingObjects;
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 
   size_t numTrailingObjects(OverloadToken<APValue>) const {
     return getResultStorageKind() == ConstantResultStorageKind::APValue;
   }
   size_t numTrailingObjects(OverloadToken<uint64_t>) const {
     return getResultStorageKind() == ConstantResultStorageKind::Int64;
   }
 
   uint64_t &Int64Result() {
     assert(getResultStorageKind() == ConstantResultStorageKind::Int64 &&
            "invalid accessor");
     return *getTrailingObjects<uint64_t>();
   }
   const uint64_t &Int64Result() const {
     return const_cast<ConstantExpr *>(this)->Int64Result();
   }
   APValue &APValueResult() {
     assert(getResultStorageKind() == ConstantResultStorageKind::APValue &&
            "invalid accessor");
     return *getTrailingObjects<APValue>();
   }
   APValue &APValueResult() const {
     return const_cast<ConstantExpr *>(this)->APValueResult();
   }
 
   ConstantExpr(Expr *SubExpr, ConstantResultStorageKind StorageKind,
                bool IsImmediateInvocation);
   ConstantExpr(EmptyShell Empty, ConstantResultStorageKind StorageKind);
 
 public:
   static ConstantExpr *Create(const ASTContext &Context, Expr *E,
                               const APValue &Result);
   static ConstantExpr *
   Create(const ASTContext &Context, Expr *E,
          ConstantResultStorageKind Storage = ConstantResultStorageKind::None,
          bool IsImmediateInvocation = false);
   static ConstantExpr *CreateEmpty(const ASTContext &Context,
                                    ConstantResultStorageKind StorageKind);
 
   static ConstantResultStorageKind getStorageKind(const APValue &Value);
   static ConstantResultStorageKind getStorageKind(const Type *T,
                                                   const ASTContext &Context);
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return SubExpr->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return SubExpr->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ConstantExprClass;
   }
 
   void SetResult(APValue Value, const ASTContext &Context) {
     MoveIntoResult(Value, Context);
   }
   void MoveIntoResult(APValue &Value, const ASTContext &Context);
 
   APValue::ValueKind getResultAPValueKind() const {
     return static_cast<APValue::ValueKind>(ConstantExprBits.APValueKind);
   }
   ConstantResultStorageKind getResultStorageKind() const {
     return static_cast<ConstantResultStorageKind>(ConstantExprBits.ResultKind);
   }
   bool isImmediateInvocation() const {
     return ConstantExprBits.IsImmediateInvocation;
   }
   bool hasAPValueResult() const {
     return ConstantExprBits.APValueKind != APValue::None;
   }
   APValue getAPValueResult() const;
   llvm::APSInt getResultAsAPSInt() const;
   // Iterators
   child_range children() { return child_range(&SubExpr, &SubExpr+1); }
   const_child_range children() const {
     return const_child_range(&SubExpr, &SubExpr + 1);
   }
 };
 
 //===----------------------------------------------------------------------===//
 // Primary Expressions.
 //===----------------------------------------------------------------------===//
 
 /// OpaqueValueExpr - An expression referring to an opaque object of a
 /// fixed type and value class.  These don't correspond to concrete
 /// syntax; instead they're used to express operations (usually copy
 /// operations) on values whose source is generally obvious from
 /// context.
 class OpaqueValueExpr : public Expr {
   friend class ASTStmtReader;
   Expr *SourceExpr;
 
 public:
   OpaqueValueExpr(SourceLocation Loc, QualType T, ExprValueKind VK,
                   ExprObjectKind OK = OK_Ordinary, Expr *SourceExpr = nullptr)
       : Expr(OpaqueValueExprClass, T, VK, OK), SourceExpr(SourceExpr) {
     setIsUnique(false);
     OpaqueValueExprBits.Loc = Loc;
     setDependence(computeDependence(this));
   }
 
   /// Given an expression which invokes a copy constructor --- i.e.  a
   /// CXXConstructExpr, possibly wrapped in an ExprWithCleanups ---
   /// find the OpaqueValueExpr that's the source of the construction.
   static const OpaqueValueExpr *findInCopyConstruct(const Expr *expr);
 
   explicit OpaqueValueExpr(EmptyShell Empty)
     : Expr(OpaqueValueExprClass, Empty) {}
 
   /// Retrieve the location of this expression.
   SourceLocation getLocation() const { return OpaqueValueExprBits.Loc; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return SourceExpr ? SourceExpr->getBeginLoc() : getLocation();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return SourceExpr ? SourceExpr->getEndLoc() : getLocation();
   }
   SourceLocation getExprLoc() const LLVM_READONLY {
     return SourceExpr ? SourceExpr->getExprLoc() : getLocation();
   }
 
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   /// The source expression of an opaque value expression is the
   /// expression which originally generated the value.  This is
   /// provided as a convenience for analyses that don't wish to
   /// precisely model the execution behavior of the program.
   ///
   /// The source expression is typically set when building the
   /// expression which binds the opaque value expression in the first
   /// place.
   Expr *getSourceExpr() const { return SourceExpr; }
 
   void setIsUnique(bool V) {
     assert((!V || SourceExpr) &&
            "unique OVEs are expected to have source expressions");
     OpaqueValueExprBits.IsUnique = V;
   }
 
   bool isUnique() const { return OpaqueValueExprBits.IsUnique; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == OpaqueValueExprClass;
   }
 };
 
 /// A reference to a declared variable, function, enum, etc.
 /// [C99 6.5.1p2]
 ///
 /// This encodes all the information about how a declaration is referenced
 /// within an expression.
 ///
 /// There are several optional constructs attached to DeclRefExprs only when
 /// they apply in order to conserve memory. These are laid out past the end of
 /// the object, and flags in the DeclRefExprBitfield track whether they exist:
 ///
 ///   DeclRefExprBits.HasQualifier:
 ///       Specifies when this declaration reference expression has a C++
 ///       nested-name-specifier.
 ///   DeclRefExprBits.HasFoundDecl:
 ///       Specifies when this declaration reference expression has a record of
 ///       a NamedDecl (different from the referenced ValueDecl) which was found
 ///       during name lookup and/or overload resolution.
 ///   DeclRefExprBits.HasTemplateKWAndArgsInfo:
 ///       Specifies when this declaration reference expression has an explicit
 ///       C++ template keyword and/or template argument list.
 ///   DeclRefExprBits.RefersToEnclosingVariableOrCapture
 ///       Specifies when this declaration reference expression (validly)
 ///       refers to an enclosed local or a captured variable.
 class DeclRefExpr final
     : public Expr,
       private llvm::TrailingObjects<DeclRefExpr, NestedNameSpecifierLoc,
                                     NamedDecl *, ASTTemplateKWAndArgsInfo,
                                     TemplateArgumentLoc> {
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
   friend TrailingObjects;
 
   /// The declaration that we are referencing.
   ValueDecl *D;
 
   /// Provides source/type location info for the declaration name
   /// embedded in D.
   DeclarationNameLoc DNLoc;
 
   size_t numTrailingObjects(OverloadToken<NestedNameSpecifierLoc>) const {
     return hasQualifier();
   }
 
   size_t numTrailingObjects(OverloadToken<NamedDecl *>) const {
     return hasFoundDecl();
   }
 
   size_t numTrailingObjects(OverloadToken<ASTTemplateKWAndArgsInfo>) const {
     return hasTemplateKWAndArgsInfo();
   }
 
   /// Test whether there is a distinct FoundDecl attached to the end of
   /// this DRE.
   bool hasFoundDecl() const { return DeclRefExprBits.HasFoundDecl; }
 
   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);
 
   /// Construct an empty declaration reference expression.
   explicit DeclRefExpr(EmptyShell Empty) : Expr(DeclRefExprClass, Empty) {}
 
 public:
   DeclRefExpr(const ASTContext &Ctx, ValueDecl *D,
               bool RefersToEnclosingVariableOrCapture, QualType T,
               ExprValueKind VK, SourceLocation L,
               const DeclarationNameLoc &LocInfo = DeclarationNameLoc(),
               NonOdrUseReason NOUR = NOUR_None);
 
   static DeclRefExpr *
   Create(const ASTContext &Context, NestedNameSpecifierLoc QualifierLoc,
          SourceLocation TemplateKWLoc, ValueDecl *D,
          bool RefersToEnclosingVariableOrCapture, SourceLocation NameLoc,
          QualType T, ExprValueKind VK, NamedDecl *FoundD = nullptr,
          const TemplateArgumentListInfo *TemplateArgs = nullptr,
          NonOdrUseReason NOUR = NOUR_None);
 
   static DeclRefExpr *
   Create(const ASTContext &Context, NestedNameSpecifierLoc QualifierLoc,
          SourceLocation TemplateKWLoc, ValueDecl *D,
          bool RefersToEnclosingVariableOrCapture,
          const DeclarationNameInfo &NameInfo, QualType T, ExprValueKind VK,
          NamedDecl *FoundD = nullptr,
          const TemplateArgumentListInfo *TemplateArgs = nullptr,
          NonOdrUseReason NOUR = NOUR_None);
 
   /// Construct an empty declaration reference expression.
   static DeclRefExpr *CreateEmpty(const ASTContext &Context, bool HasQualifier,
                                   bool HasFoundDecl,
                                   bool HasTemplateKWAndArgsInfo,
                                   unsigned NumTemplateArgs);
 
   ValueDecl *getDecl() { return D; }
   const ValueDecl *getDecl() const { return D; }
   void setDecl(ValueDecl *NewD);
 
   DeclarationNameInfo getNameInfo() const {
     return DeclarationNameInfo(getDecl()->getDeclName(), getLocation(), DNLoc);
   }
 
   SourceLocation getLocation() const { return DeclRefExprBits.Loc; }
   void setLocation(SourceLocation L) { DeclRefExprBits.Loc = L; }
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   /// Determine whether this declaration reference was preceded by a
   /// C++ nested-name-specifier, e.g., \c N::foo.
   bool hasQualifier() const { return DeclRefExprBits.HasQualifier; }
 
   /// If the name was qualified, retrieves the nested-name-specifier
   /// that precedes the name, with source-location information.
   NestedNameSpecifierLoc getQualifierLoc() const {
     if (!hasQualifier())
       return NestedNameSpecifierLoc();
     return *getTrailingObjects<NestedNameSpecifierLoc>();
   }
 
   /// If the name was qualified, retrieves the nested-name-specifier
   /// that precedes the name. Otherwise, returns NULL.
   NestedNameSpecifier *getQualifier() const {
     return getQualifierLoc().getNestedNameSpecifier();
   }
 
   /// Get the NamedDecl through which this reference occurred.
   ///
   /// This Decl may be different from the ValueDecl actually referred to in the
   /// presence of using declarations, etc. It always returns non-NULL, and may
   /// simple return the ValueDecl when appropriate.
 
   NamedDecl *getFoundDecl() {
     return hasFoundDecl() ? *getTrailingObjects<NamedDecl *>() : D;
   }
 
   /// Get the NamedDecl through which this reference occurred.
   /// See non-const variant.
   const NamedDecl *getFoundDecl() const {
     return hasFoundDecl() ? *getTrailingObjects<NamedDecl *>() : D;
   }
 
   bool hasTemplateKWAndArgsInfo() const {
     return DeclRefExprBits.HasTemplateKWAndArgsInfo;
   }
 
   /// Retrieve the location of the template keyword preceding
   /// this name, if any.
   SourceLocation getTemplateKeywordLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->TemplateKWLoc;
   }
 
   /// Retrieve the location of the left angle bracket starting the
   /// explicit template argument list following the name, if any.
   SourceLocation getLAngleLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->LAngleLoc;
   }
 
   /// Retrieve the location of the right angle bracket ending the
   /// explicit template argument list following the name, if any.
   SourceLocation getRAngleLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->RAngleLoc;
   }
 
   /// Determines whether the name in this declaration reference
   /// was preceded by the template keyword.
   bool hasTemplateKeyword() const { return getTemplateKeywordLoc().isValid(); }
 
   /// Determines whether this declaration reference was followed by an
   /// explicit template argument list.
   bool hasExplicitTemplateArgs() const { return getLAngleLoc().isValid(); }
 
   /// Copies the template arguments (if present) into the given
   /// structure.
   void copyTemplateArgumentsInto(TemplateArgumentListInfo &List) const {
     if (hasExplicitTemplateArgs())
       getTrailingObjects<ASTTemplateKWAndArgsInfo>()->copyInto(
           getTrailingObjects<TemplateArgumentLoc>(), List);
   }
 
   /// Retrieve the template arguments provided as part of this
   /// template-id.
   const TemplateArgumentLoc *getTemplateArgs() const {
     if (!hasExplicitTemplateArgs())
       return nullptr;
     return getTrailingObjects<TemplateArgumentLoc>();
   }
 
   /// Retrieve the number of template arguments provided as part of this
   /// template-id.
   unsigned getNumTemplateArgs() const {
     if (!hasExplicitTemplateArgs())
       return 0;
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->NumTemplateArgs;
   }
 
   ArrayRef<TemplateArgumentLoc> template_arguments() const {
     return {getTemplateArgs(), getNumTemplateArgs()};
   }
 
   /// Returns true if this expression refers to a function that
   /// was resolved from an overloaded set having size greater than 1.
   bool hadMultipleCandidates() const {
     return DeclRefExprBits.HadMultipleCandidates;
   }
   /// Sets the flag telling whether this expression refers to
   /// a function that was resolved from an overloaded set having size
   /// greater than 1.
   void setHadMultipleCandidates(bool V = true) {
     DeclRefExprBits.HadMultipleCandidates = V;
   }
 
   /// Is this expression a non-odr-use reference, and if so, why?
   NonOdrUseReason isNonOdrUse() const {
     return static_cast<NonOdrUseReason>(DeclRefExprBits.NonOdrUseReason);
   }
 
   /// Does this DeclRefExpr refer to an enclosing local or a captured
   /// variable?
   bool refersToEnclosingVariableOrCapture() const {
     return DeclRefExprBits.RefersToEnclosingVariableOrCapture;
   }
 
   bool isImmediateEscalating() const {
     return DeclRefExprBits.IsImmediateEscalating;
   }
 
   void setIsImmediateEscalating(bool Set) {
     DeclRefExprBits.IsImmediateEscalating = Set;
   }
 
   bool isCapturedByCopyInLambdaWithExplicitObjectParameter() const {
     return DeclRefExprBits.CapturedByCopyInLambdaWithExplicitObjectParameter;
   }
 
   void setCapturedByCopyInLambdaWithExplicitObjectParameter(
       bool Set, const ASTContext &Context) {
     DeclRefExprBits.CapturedByCopyInLambdaWithExplicitObjectParameter = Set;
     setDependence(computeDependence(this, Context));
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == DeclRefExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 class IntegerLiteral : public Expr, public APIntStorage {
   SourceLocation Loc;
 
   /// Construct an empty integer literal.
   explicit IntegerLiteral(EmptyShell Empty)
     : Expr(IntegerLiteralClass, Empty) { }
 
 public:
   // type should be IntTy, LongTy, LongLongTy, UnsignedIntTy, UnsignedLongTy,
   // or UnsignedLongLongTy
   IntegerLiteral(const ASTContext &C, const llvm::APInt &V, QualType type,
                  SourceLocation l);
 
   /// Returns a new integer literal with value 'V' and type 'type'.
   /// \param type - either IntTy, LongTy, LongLongTy, UnsignedIntTy,
   /// UnsignedLongTy, or UnsignedLongLongTy which should match the size of V
   /// \param V - the value that the returned integer literal contains.
   static IntegerLiteral *Create(const ASTContext &C, const llvm::APInt &V,
                                 QualType type, SourceLocation l);
   /// Returns a new empty integer literal.
   static IntegerLiteral *Create(const ASTContext &C, EmptyShell Empty);
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return Loc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return Loc; }
 
   /// Retrieve the location of the literal.
   SourceLocation getLocation() const { return Loc; }
 
   void setLocation(SourceLocation Location) { Loc = Location; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == IntegerLiteralClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 class FixedPointLiteral : public Expr, public APIntStorage {
   SourceLocation Loc;
   unsigned Scale;
 
   /// \brief Construct an empty fixed-point literal.
   explicit FixedPointLiteral(EmptyShell Empty)
       : Expr(FixedPointLiteralClass, Empty) {}
 
  public:
   FixedPointLiteral(const ASTContext &C, const llvm::APInt &V, QualType type,
                     SourceLocation l, unsigned Scale);
 
   // Store the int as is without any bit shifting.
   static FixedPointLiteral *CreateFromRawInt(const ASTContext &C,
                                              const llvm::APInt &V,
                                              QualType type, SourceLocation l,
                                              unsigned Scale);
 
   /// Returns an empty fixed-point literal.
   static FixedPointLiteral *Create(const ASTContext &C, EmptyShell Empty);
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return Loc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return Loc; }
 
   /// \brief Retrieve the location of the literal.
   SourceLocation getLocation() const { return Loc; }
 
   void setLocation(SourceLocation Location) { Loc = Location; }
 
   unsigned getScale() const { return Scale; }
   void setScale(unsigned S) { Scale = S; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == FixedPointLiteralClass;
   }
 
   std::string getValueAsString(unsigned Radix) const;
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 enum class CharacterLiteralKind { Ascii, Wide, UTF8, UTF16, UTF32 };
 
 class CharacterLiteral : public Expr {
   unsigned Value;
   SourceLocation Loc;
 public:
   // type should be IntTy
   CharacterLiteral(unsigned value, CharacterLiteralKind kind, QualType type,
                    SourceLocation l)
       : Expr(CharacterLiteralClass, type, VK_PRValue, OK_Ordinary),
         Value(value), Loc(l) {
     CharacterLiteralBits.Kind = llvm::to_underlying(kind);
     setDependence(ExprDependence::None);
   }
 
   /// Construct an empty character literal.
   CharacterLiteral(EmptyShell Empty) : Expr(CharacterLiteralClass, Empty) { }
 
   SourceLocation getLocation() const { return Loc; }
   CharacterLiteralKind getKind() const {
     return static_cast<CharacterLiteralKind>(CharacterLiteralBits.Kind);
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return Loc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return Loc; }
 
   unsigned getValue() const { return Value; }
 
   void setLocation(SourceLocation Location) { Loc = Location; }
   void setKind(CharacterLiteralKind kind) {
     CharacterLiteralBits.Kind = llvm::to_underlying(kind);
   }
   void setValue(unsigned Val) { Value = Val; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == CharacterLiteralClass;
   }
 
   static void print(unsigned val, CharacterLiteralKind Kind, raw_ostream &OS);
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 class FloatingLiteral : public Expr, private APFloatStorage {
   SourceLocation Loc;
 
   FloatingLiteral(const ASTContext &C, const llvm::APFloat &V, bool isexact,
                   QualType Type, SourceLocation L);
 
   /// Construct an empty floating-point literal.
   explicit FloatingLiteral(const ASTContext &C, EmptyShell Empty);
 
 public:
   static FloatingLiteral *Create(const ASTContext &C, const llvm::APFloat &V,
                                  bool isexact, QualType Type, SourceLocation L);
   static FloatingLiteral *Create(const ASTContext &C, EmptyShell Empty);
 
   llvm::APFloat getValue() const {
     return APFloatStorage::getValue(getSemantics());
   }
   void setValue(const ASTContext &C, const llvm::APFloat &Val) {
     assert(&getSemantics() == &Val.getSemantics() && "Inconsistent semantics");
     APFloatStorage::setValue(C, Val);
   }
 
   /// Get a raw enumeration value representing the floating-point semantics of
   /// this literal (32-bit IEEE, x87, ...), suitable for serialization.
   llvm::APFloatBase::Semantics getRawSemantics() const {
     return static_cast<llvm::APFloatBase::Semantics>(
         FloatingLiteralBits.Semantics);
   }
 
   /// Set the raw enumeration value representing the floating-point semantics of
   /// this literal (32-bit IEEE, x87, ...), suitable for serialization.
   void setRawSemantics(llvm::APFloatBase::Semantics Sem) {
     FloatingLiteralBits.Semantics = Sem;
   }
 
   /// Return the APFloat semantics this literal uses.
   const llvm::fltSemantics &getSemantics() const {
     return llvm::APFloatBase::EnumToSemantics(
         static_cast<llvm::APFloatBase::Semantics>(
             FloatingLiteralBits.Semantics));
   }
 
   /// Set the APFloat semantics this literal uses.
   void setSemantics(const llvm::fltSemantics &Sem) {
     FloatingLiteralBits.Semantics = llvm::APFloatBase::SemanticsToEnum(Sem);
   }
 
   bool isExact() const { return FloatingLiteralBits.IsExact; }
   void setExact(bool E) { FloatingLiteralBits.IsExact = E; }
 
   /// 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 getValueAsApproximateDouble() const;
 
   SourceLocation getLocation() const { return Loc; }
   void setLocation(SourceLocation L) { Loc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return Loc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return Loc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == FloatingLiteralClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 /// ImaginaryLiteral - We support imaginary integer and floating point literals,
 /// like "1.0i".  We represent these as a wrapper around FloatingLiteral and
 /// IntegerLiteral classes.  Instances of this class always have a Complex type
 /// whose element type matches the subexpression.
 ///
 class ImaginaryLiteral : public Expr {
   Stmt *Val;
 public:
   ImaginaryLiteral(Expr *val, QualType Ty)
       : Expr(ImaginaryLiteralClass, Ty, VK_PRValue, OK_Ordinary), Val(val) {
     setDependence(ExprDependence::None);
   }
 
   /// Build an empty imaginary literal.
   explicit ImaginaryLiteral(EmptyShell Empty)
     : Expr(ImaginaryLiteralClass, Empty) { }
 
   const Expr *getSubExpr() const { return cast<Expr>(Val); }
   Expr *getSubExpr() { return cast<Expr>(Val); }
   void setSubExpr(Expr *E) { Val = E; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return Val->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY { return Val->getEndLoc(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ImaginaryLiteralClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Val, &Val+1); }
   const_child_range children() const {
     return const_child_range(&Val, &Val + 1);
   }
 };
 
 enum class StringLiteralKind {
   Ordinary,
   Wide,
   UTF8,
   UTF16,
   UTF32,
   Unevaluated,
   // Binary kind of string literal is used for the data coming via #embed
   // directive. File's binary contents is transformed to a special kind of
   // string literal that in some cases may be used directly as an initializer
   // and some features of classic string literals are not applicable to this
   // kind of a string literal, for example finding a particular byte's source
   // location for better diagnosing.
   Binary
 };
 
 /// StringLiteral - This represents a string literal expression, e.g. "foo"
 /// or L"bar" (wide strings). The actual string data can be obtained with
 /// getBytes() and is NOT null-terminated. The length of the string data is
 /// determined by calling getByteLength().
 ///
 /// The C type for a string is always a ConstantArrayType. In C++, the char
 /// type is const qualified, in C it is not.
 ///
 /// Note that strings in C can be formed by concatenation of multiple string
 /// literal pptokens in translation phase #6. This keeps track of the locations
 /// of each of these pieces.
 ///
 /// Strings in C can also be truncated and extended by assigning into arrays,
 /// e.g. with constructs like:
 ///   char X[2] = "foobar";
 /// In this case, getByteLength() will return 6, but the string literal will
 /// have type "char[2]".
 class StringLiteral final
     : public Expr,
       private llvm::TrailingObjects<StringLiteral, unsigned, SourceLocation,
                                     char> {
   friend class ASTStmtReader;
   friend TrailingObjects;
 
   /// StringLiteral is followed by several trailing objects. They are in order:
   ///
   /// * A single unsigned storing the length in characters of this string. The
   ///   length in bytes is this length times the width of a single character.
   ///   Always present and stored as a trailing objects because storing it in
   ///   StringLiteral would increase the size of StringLiteral by sizeof(void *)
   ///   due to alignment requirements. If you add some data to StringLiteral,
   ///   consider moving it inside StringLiteral.
   ///
   /// * An array of getNumConcatenated() SourceLocation, one for each of the
   ///   token this string is made of.
   ///
   /// * An array of getByteLength() char used to store the string data.
 
   unsigned numTrailingObjects(OverloadToken<unsigned>) const { return 1; }
   unsigned numTrailingObjects(OverloadToken<SourceLocation>) const {
     return getNumConcatenated();
   }
 
   unsigned numTrailingObjects(OverloadToken<char>) const {
     return getByteLength();
   }
 
   char *getStrDataAsChar() { return getTrailingObjects<char>(); }
   const char *getStrDataAsChar() const { return getTrailingObjects<char>(); }
 
   const uint16_t *getStrDataAsUInt16() const {
     return reinterpret_cast<const uint16_t *>(getTrailingObjects<char>());
   }
 
   const uint32_t *getStrDataAsUInt32() const {
     return reinterpret_cast<const uint32_t *>(getTrailingObjects<char>());
   }
 
   /// Build a string literal.
   StringLiteral(const ASTContext &Ctx, StringRef Str, StringLiteralKind Kind,
                 bool Pascal, QualType Ty, const SourceLocation *Loc,
                 unsigned NumConcatenated);
 
   /// Build an empty string literal.
   StringLiteral(EmptyShell Empty, unsigned NumConcatenated, unsigned Length,
                 unsigned CharByteWidth);
 
   /// Map a target and string kind to the appropriate character width.
   static unsigned mapCharByteWidth(TargetInfo const &Target,
                                    StringLiteralKind SK);
 
   /// Set one of the string literal token.
   void setStrTokenLoc(unsigned TokNum, SourceLocation L) {
     assert(TokNum < getNumConcatenated() && "Invalid tok number");
     getTrailingObjects<SourceLocation>()[TokNum] = L;
   }
 
 public:
   /// This is the "fully general" constructor that allows representation of
   /// strings formed from multiple concatenated tokens.
   static StringLiteral *Create(const ASTContext &Ctx, StringRef Str,
                                StringLiteralKind Kind, bool Pascal, QualType Ty,
                                const SourceLocation *Loc,
                                unsigned NumConcatenated);
 
   /// Simple constructor for string literals made from one token.
   static StringLiteral *Create(const ASTContext &Ctx, StringRef Str,
                                StringLiteralKind Kind, bool Pascal, QualType Ty,
                                SourceLocation Loc) {
     return Create(Ctx, Str, Kind, Pascal, Ty, &Loc, 1);
   }
 
   /// Construct an empty string literal.
   static StringLiteral *CreateEmpty(const ASTContext &Ctx,
                                     unsigned NumConcatenated, unsigned Length,
                                     unsigned CharByteWidth);
 
   StringRef getString() const {
     assert((isUnevaluated() || getCharByteWidth() == 1) &&
            "This function is used in places that assume strings use char");
     return StringRef(getStrDataAsChar(), getByteLength());
   }
 
   /// Allow access to clients that need the byte representation, such as
   /// ASTWriterStmt::VisitStringLiteral().
   StringRef getBytes() const {
     // FIXME: StringRef may not be the right type to use as a result for this.
     return StringRef(getStrDataAsChar(), getByteLength());
   }
 
   void outputString(raw_ostream &OS) const;
 
   uint32_t getCodeUnit(size_t i) const {
     assert(i < getLength() && "out of bounds access");
     switch (getCharByteWidth()) {
     case 1:
       return static_cast<unsigned char>(getStrDataAsChar()[i]);
     case 2:
       return getStrDataAsUInt16()[i];
     case 4:
       return getStrDataAsUInt32()[i];
     }
     llvm_unreachable("Unsupported character width!");
   }
 
   // Get code unit but preserve sign info.
   int64_t getCodeUnitS(size_t I, uint64_t BitWidth) const {
     int64_t V = getCodeUnit(I);
     if (isOrdinary() || isWide()) {
       // Ordinary and wide string literals have types that can be signed.
       // It is important for checking C23 constexpr initializers.
       unsigned Width = getCharByteWidth() * BitWidth;
       llvm::APInt AInt(Width, (uint64_t)V);
       V = AInt.getSExtValue();
     }
     return V;
   }
 
   unsigned getByteLength() const { return getCharByteWidth() * getLength(); }
   unsigned getLength() const { return *getTrailingObjects<unsigned>(); }
   unsigned getCharByteWidth() const { return StringLiteralBits.CharByteWidth; }
 
   StringLiteralKind getKind() const {
     return static_cast<StringLiteralKind>(StringLiteralBits.Kind);
   }
 
   bool isOrdinary() const { return getKind() == StringLiteralKind::Ordinary; }
   bool isWide() const { return getKind() == StringLiteralKind::Wide; }
   bool isUTF8() const { return getKind() == StringLiteralKind::UTF8; }
   bool isUTF16() const { return getKind() == StringLiteralKind::UTF16; }
   bool isUTF32() const { return getKind() == StringLiteralKind::UTF32; }
   bool isUnevaluated() const { return getKind() == StringLiteralKind::Unevaluated; }
   bool isPascal() const { return StringLiteralBits.IsPascal; }
 
   bool containsNonAscii() const {
     for (auto c : getString())
       if (!isASCII(c))
         return true;
     return false;
   }
 
   bool containsNonAsciiOrNull() const {
     for (auto c : getString())
       if (!isASCII(c) || !c)
         return true;
     return false;
   }
 
   /// getNumConcatenated - Get the number of string literal tokens that were
   /// concatenated in translation phase #6 to form this string literal.
   unsigned getNumConcatenated() const {
     return StringLiteralBits.NumConcatenated;
   }
 
   /// Get one of the string literal token.
   SourceLocation getStrTokenLoc(unsigned TokNum) const {
     assert(TokNum < getNumConcatenated() && "Invalid tok number");
     return getTrailingObjects<SourceLocation>()[TokNum];
   }
 
   /// 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.
   ///
   SourceLocation
   getLocationOfByte(unsigned ByteNo, const SourceManager &SM,
                     const LangOptions &Features, const TargetInfo &Target,
                     unsigned *StartToken = nullptr,
                     unsigned *StartTokenByteOffset = nullptr) const;
 
   typedef const SourceLocation *tokloc_iterator;
 
   tokloc_iterator tokloc_begin() const {
     return getTrailingObjects<SourceLocation>();
   }
 
   tokloc_iterator tokloc_end() const {
     return getTrailingObjects<SourceLocation>() + getNumConcatenated();
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return *tokloc_begin(); }
   SourceLocation getEndLoc() const LLVM_READONLY { return *(tokloc_end() - 1); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == StringLiteralClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 enum class PredefinedIdentKind {
   Func,
   Function,
   LFunction, // Same as Function, but as wide string.
   FuncDName,
   FuncSig,
   LFuncSig, // Same as FuncSig, but as wide string
   PrettyFunction,
   /// The same as PrettyFunction, except that the
   /// 'virtual' keyword is omitted for virtual member functions.
   PrettyFunctionNoVirtual
 };
 
 /// [C99 6.4.2.2] - A predefined identifier such as __func__.
 class PredefinedExpr final
     : public Expr,
       private llvm::TrailingObjects<PredefinedExpr, Stmt *> {
   friend class ASTStmtReader;
   friend TrailingObjects;
 
   // PredefinedExpr is optionally followed by a single trailing
   // "Stmt *" for the predefined identifier. It is present if and only if
   // hasFunctionName() is true and is always a "StringLiteral *".
 
   PredefinedExpr(SourceLocation L, QualType FNTy, PredefinedIdentKind IK,
                  bool IsTransparent, StringLiteral *SL);
 
   explicit PredefinedExpr(EmptyShell Empty, bool HasFunctionName);
 
   /// True if this PredefinedExpr has storage for a function name.
   bool hasFunctionName() const { return PredefinedExprBits.HasFunctionName; }
 
   void setFunctionName(StringLiteral *SL) {
     assert(hasFunctionName() &&
            "This PredefinedExpr has no storage for a function name!");
     *getTrailingObjects<Stmt *>() = SL;
   }
 
 public:
   /// Create a PredefinedExpr.
   ///
   /// If IsTransparent, the PredefinedExpr is transparently handled as a
   /// StringLiteral.
   static PredefinedExpr *Create(const ASTContext &Ctx, SourceLocation L,
                                 QualType FNTy, PredefinedIdentKind IK,
                                 bool IsTransparent, StringLiteral *SL);
 
   /// Create an empty PredefinedExpr.
   static PredefinedExpr *CreateEmpty(const ASTContext &Ctx,
                                      bool HasFunctionName);
 
   PredefinedIdentKind getIdentKind() const {
     return static_cast<PredefinedIdentKind>(PredefinedExprBits.Kind);
   }
 
   bool isTransparent() const { return PredefinedExprBits.IsTransparent; }
 
   SourceLocation getLocation() const { return PredefinedExprBits.Loc; }
   void setLocation(SourceLocation L) { PredefinedExprBits.Loc = L; }
 
   StringLiteral *getFunctionName() {
     return hasFunctionName()
                ? static_cast<StringLiteral *>(*getTrailingObjects<Stmt *>())
                : nullptr;
   }
 
   const StringLiteral *getFunctionName() const {
     return hasFunctionName()
                ? static_cast<StringLiteral *>(*getTrailingObjects<Stmt *>())
                : nullptr;
   }
 
   static StringRef getIdentKindName(PredefinedIdentKind IK);
   StringRef getIdentKindName() const {
     return getIdentKindName(getIdentKind());
   }
 
   static std::string ComputeName(PredefinedIdentKind IK,
                                  const Decl *CurrentDecl,
                                  bool ForceElaboratedPrinting = false);
 
   SourceLocation getBeginLoc() const { return getLocation(); }
   SourceLocation getEndLoc() const { return getLocation(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == PredefinedExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(getTrailingObjects<Stmt *>(),
                        getTrailingObjects<Stmt *>() + hasFunctionName());
   }
 
   const_child_range children() const {
     return const_child_range(getTrailingObjects<Stmt *>(),
                              getTrailingObjects<Stmt *>() + hasFunctionName());
   }
 };
 
 /// This expression type represents an asterisk in an OpenACC Size-Expr, used in
 /// the 'tile' and 'gang' clauses. It is of 'int' type, but should not be
 /// evaluated.
 class OpenACCAsteriskSizeExpr final : public Expr {
   friend class ASTStmtReader;
   SourceLocation AsteriskLoc;
 
   OpenACCAsteriskSizeExpr(SourceLocation AsteriskLoc, QualType IntTy)
       : Expr(OpenACCAsteriskSizeExprClass, IntTy, VK_PRValue, OK_Ordinary),
         AsteriskLoc(AsteriskLoc) {}
 
   void setAsteriskLocation(SourceLocation Loc) { AsteriskLoc = Loc; }
 
 public:
   static OpenACCAsteriskSizeExpr *Create(const ASTContext &C,
                                          SourceLocation Loc);
   static OpenACCAsteriskSizeExpr *CreateEmpty(const ASTContext &C);
 
   SourceLocation getBeginLoc() const { return AsteriskLoc; }
   SourceLocation getEndLoc() const { return AsteriskLoc; }
   SourceLocation getLocation() const { return AsteriskLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == OpenACCAsteriskSizeExprClass;
   }
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 // This represents a use of the __builtin_sycl_unique_stable_name, which takes a
 // type-id, and at CodeGen time emits a unique string representation of the
 // type in a way that permits us to properly encode information about the SYCL
 // kernels.
 class SYCLUniqueStableNameExpr final : public Expr {
   friend class ASTStmtReader;
   SourceLocation OpLoc, LParen, RParen;
   TypeSourceInfo *TypeInfo;
 
   SYCLUniqueStableNameExpr(EmptyShell Empty, QualType ResultTy);
   SYCLUniqueStableNameExpr(SourceLocation OpLoc, SourceLocation LParen,
                            SourceLocation RParen, QualType ResultTy,
                            TypeSourceInfo *TSI);
 
   void setTypeSourceInfo(TypeSourceInfo *Ty) { TypeInfo = Ty; }
 
   void setLocation(SourceLocation L) { OpLoc = L; }
   void setLParenLocation(SourceLocation L) { LParen = L; }
   void setRParenLocation(SourceLocation L) { RParen = L; }
 
 public:
   TypeSourceInfo *getTypeSourceInfo() { return TypeInfo; }
 
   const TypeSourceInfo *getTypeSourceInfo() const { return TypeInfo; }
 
   static SYCLUniqueStableNameExpr *
   Create(const ASTContext &Ctx, SourceLocation OpLoc, SourceLocation LParen,
          SourceLocation RParen, TypeSourceInfo *TSI);
 
   static SYCLUniqueStableNameExpr *CreateEmpty(const ASTContext &Ctx);
 
   SourceLocation getBeginLoc() const { return getLocation(); }
   SourceLocation getEndLoc() const { return RParen; }
   SourceLocation getLocation() const { return OpLoc; }
   SourceLocation getLParenLocation() const { return LParen; }
   SourceLocation getRParenLocation() const { return RParen; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == SYCLUniqueStableNameExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   // Convenience function to generate the name of the currently stored type.
   std::string ComputeName(ASTContext &Context) const;
 
   // Get the generated name of the type.  Note that this only works after all
   // kernels have been instantiated.
   static std::string ComputeName(ASTContext &Context, QualType Ty);
 };
 
 /// ParenExpr - This represents a parenthesized expression, e.g. "(1)".  This
 /// AST node is only formed if full location information is requested.
 class ParenExpr : public Expr {
   SourceLocation L, R;
   Stmt *Val;
 
 public:
   ParenExpr(SourceLocation l, SourceLocation r, Expr *val)
       : Expr(ParenExprClass, val->getType(), val->getValueKind(),
              val->getObjectKind()),
         L(l), R(r), Val(val) {
     ParenExprBits.ProducedByFoldExpansion = false;
     setDependence(computeDependence(this));
   }
 
   /// Construct an empty parenthesized expression.
   explicit ParenExpr(EmptyShell Empty)
     : Expr(ParenExprClass, Empty) { }
 
   const Expr *getSubExpr() const { return cast<Expr>(Val); }
   Expr *getSubExpr() { return cast<Expr>(Val); }
   void setSubExpr(Expr *E) { Val = E; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return L; }
   SourceLocation getEndLoc() const LLVM_READONLY { return R; }
 
   /// Get the location of the left parentheses '('.
   SourceLocation getLParen() const { return L; }
   void setLParen(SourceLocation Loc) { L = Loc; }
 
   /// Get the location of the right parentheses ')'.
   SourceLocation getRParen() const { return R; }
   void setRParen(SourceLocation Loc) { R = Loc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ParenExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Val, &Val+1); }
   const_child_range children() const {
     return const_child_range(&Val, &Val + 1);
   }
 
   bool isProducedByFoldExpansion() const {
     return ParenExprBits.ProducedByFoldExpansion != 0;
   }
   void setIsProducedByFoldExpansion(bool ProducedByFoldExpansion = true) {
     ParenExprBits.ProducedByFoldExpansion = ProducedByFoldExpansion;
   }
 };
 
 /// UnaryOperator - This represents the unary-expression's (except sizeof and
 /// alignof), the postinc/postdec operators from postfix-expression, and various
 /// extensions.
 ///
 /// Notes on various nodes:
 ///
 /// Real/Imag - These return the real/imag part of a complex operand.  If
 ///   applied to a non-complex value, the former returns its operand and the
 ///   later returns zero in the type of the operand.
 ///
 class UnaryOperator final
     : public Expr,
       private llvm::TrailingObjects<UnaryOperator, FPOptionsOverride> {
   Stmt *Val;
 
   size_t numTrailingObjects(OverloadToken<FPOptionsOverride>) const {
     return UnaryOperatorBits.HasFPFeatures ? 1 : 0;
   }
 
   FPOptionsOverride &getTrailingFPFeatures() {
     assert(UnaryOperatorBits.HasFPFeatures);
     return *getTrailingObjects<FPOptionsOverride>();
   }
 
   const FPOptionsOverride &getTrailingFPFeatures() const {
     assert(UnaryOperatorBits.HasFPFeatures);
     return *getTrailingObjects<FPOptionsOverride>();
   }
 
 public:
   typedef UnaryOperatorKind Opcode;
 
 protected:
   UnaryOperator(const ASTContext &Ctx, Expr *input, Opcode opc, QualType type,
                 ExprValueKind VK, ExprObjectKind OK, SourceLocation l,
                 bool CanOverflow, FPOptionsOverride FPFeatures);
 
   /// Build an empty unary operator.
   explicit UnaryOperator(bool HasFPFeatures, EmptyShell Empty)
       : Expr(UnaryOperatorClass, Empty) {
     UnaryOperatorBits.Opc = UO_AddrOf;
     UnaryOperatorBits.HasFPFeatures = HasFPFeatures;
   }
 
 public:
   static UnaryOperator *CreateEmpty(const ASTContext &C, bool hasFPFeatures);
 
   static UnaryOperator *Create(const ASTContext &C, Expr *input, Opcode opc,
                                QualType type, ExprValueKind VK,
                                ExprObjectKind OK, SourceLocation l,
                                bool CanOverflow, FPOptionsOverride FPFeatures);
 
   Opcode getOpcode() const {
     return static_cast<Opcode>(UnaryOperatorBits.Opc);
   }
   void setOpcode(Opcode Opc) { UnaryOperatorBits.Opc = Opc; }
 
   Expr *getSubExpr() const { return cast<Expr>(Val); }
   void setSubExpr(Expr *E) { Val = E; }
 
   /// getOperatorLoc - Return the location of the operator.
   SourceLocation getOperatorLoc() const { return UnaryOperatorBits.Loc; }
   void setOperatorLoc(SourceLocation L) { UnaryOperatorBits.Loc = L; }
 
   /// Returns true if the unary operator can cause an overflow. For instance,
   ///   signed int i = INT_MAX; i++;
   ///   signed char c = CHAR_MAX; c++;
   /// Due to integer promotions, c++ is promoted to an int before the postfix
   /// increment, and the result is an int that cannot overflow. However, i++
   /// can overflow.
   bool canOverflow() const { return UnaryOperatorBits.CanOverflow; }
   void setCanOverflow(bool C) { UnaryOperatorBits.CanOverflow = C; }
 
   /// Get the FP contractibility status of this operator. Only meaningful for
   /// operations on floating point types.
   bool isFPContractableWithinStatement(const LangOptions &LO) const {
     return getFPFeaturesInEffect(LO).allowFPContractWithinStatement();
   }
 
   /// Get the FENV_ACCESS status of this operator. Only meaningful for
   /// operations on floating point types.
   bool isFEnvAccessOn(const LangOptions &LO) const {
     return getFPFeaturesInEffect(LO).getAllowFEnvAccess();
   }
 
   /// isPostfix - Return true if this is a postfix operation, like x++.
   static bool isPostfix(Opcode Op) {
     return Op == UO_PostInc || Op == UO_PostDec;
   }
 
   /// isPrefix - Return true if this is a prefix operation, like --x.
   static bool isPrefix(Opcode Op) {
     return Op == UO_PreInc || Op == UO_PreDec;
   }
 
   bool isPrefix() const { return isPrefix(getOpcode()); }
   bool isPostfix() const { return isPostfix(getOpcode()); }
 
   static bool isIncrementOp(Opcode Op) {
     return Op == UO_PreInc || Op == UO_PostInc;
   }
   bool isIncrementOp() const {
     return isIncrementOp(getOpcode());
   }
 
   static bool isDecrementOp(Opcode Op) {
     return Op == UO_PreDec || Op == UO_PostDec;
   }
   bool isDecrementOp() const {
     return isDecrementOp(getOpcode());
   }
 
   static bool isIncrementDecrementOp(Opcode Op) { return Op <= UO_PreDec; }
   bool isIncrementDecrementOp() const {
     return isIncrementDecrementOp(getOpcode());
   }
 
   static bool isArithmeticOp(Opcode Op) {
     return Op >= UO_Plus && Op <= UO_LNot;
   }
   bool isArithmeticOp() const { return isArithmeticOp(getOpcode()); }
 
   /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
   /// corresponds to, e.g. "sizeof" or "[pre]++"
   static StringRef getOpcodeStr(Opcode Op);
 
   /// Retrieve the unary opcode that corresponds to the given
   /// overloaded operator.
   static Opcode getOverloadedOpcode(OverloadedOperatorKind OO, bool Postfix);
 
   /// Retrieve the overloaded operator kind that corresponds to
   /// the given unary opcode.
   static OverloadedOperatorKind getOverloadedOperator(Opcode Opc);
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return isPostfix() ? Val->getBeginLoc() : getOperatorLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return isPostfix() ? getOperatorLoc() : Val->getEndLoc();
   }
   SourceLocation getExprLoc() const { return getOperatorLoc(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == UnaryOperatorClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Val, &Val+1); }
   const_child_range children() const {
     return const_child_range(&Val, &Val + 1);
   }
 
   /// Is FPFeatures in Trailing Storage?
   bool hasStoredFPFeatures() const { return UnaryOperatorBits.HasFPFeatures; }
 
   /// Get FPFeatures from trailing storage.
   FPOptionsOverride getStoredFPFeatures() const {
     return getTrailingFPFeatures();
   }
 
   /// Get the store FPOptionsOverride or default if not stored.
   FPOptionsOverride getStoredFPFeaturesOrDefault() const {
     return hasStoredFPFeatures() ? getStoredFPFeatures() : FPOptionsOverride();
   }
 
 protected:
   /// Set FPFeatures in trailing storage, used by Serialization & ASTImporter.
   void setStoredFPFeatures(FPOptionsOverride F) { getTrailingFPFeatures() = F; }
 
 public:
   /// Get the FP features status of this operator. Only meaningful for
   /// operations on floating point types.
   FPOptions getFPFeaturesInEffect(const LangOptions &LO) const {
     if (UnaryOperatorBits.HasFPFeatures)
       return getStoredFPFeatures().applyOverrides(LO);
     return FPOptions::defaultWithoutTrailingStorage(LO);
   }
   FPOptionsOverride getFPOptionsOverride() const {
     if (UnaryOperatorBits.HasFPFeatures)
       return getStoredFPFeatures();
     return FPOptionsOverride();
   }
 
   friend TrailingObjects;
   friend class ASTNodeImporter;
   friend class ASTReader;
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 };
 
 /// Helper class for OffsetOfExpr.
 
 // __builtin_offsetof(type, identifier(.identifier|[expr])*)
 class OffsetOfNode {
 public:
   /// The kind of offsetof node we have.
   enum Kind {
     /// An index into an array.
     Array = 0x00,
     /// A field.
     Field = 0x01,
     /// A field in a dependent type, known only by its name.
     Identifier = 0x02,
     /// An implicit indirection through a C++ base class, when the
     /// field found is in a base class.
     Base = 0x03
   };
 
 private:
   enum { MaskBits = 2, Mask = 0x03 };
 
   /// The source range that covers this part of the designator.
   SourceRange Range;
 
   /// The data describing the designator, which comes in three
   /// different forms, depending on the lower two bits.
   ///   - An unsigned index into the array of Expr*'s stored after this node
   ///     in memory, for [constant-expression] designators.
   ///   - A FieldDecl*, for references to a known field.
   ///   - An IdentifierInfo*, for references to a field with a given name
   ///     when the class type is dependent.
   ///   - A CXXBaseSpecifier*, for references that look at a field in a
   ///     base class.
   uintptr_t Data;
 
 public:
   /// Create an offsetof node that refers to an array element.
   OffsetOfNode(SourceLocation LBracketLoc, unsigned Index,
                SourceLocation RBracketLoc)
       : Range(LBracketLoc, RBracketLoc), Data((Index << 2) | Array) {}
 
   /// Create an offsetof node that refers to a field.
   OffsetOfNode(SourceLocation DotLoc, FieldDecl *Field, SourceLocation NameLoc)
       : Range(DotLoc.isValid() ? DotLoc : NameLoc, NameLoc),
         Data(reinterpret_cast<uintptr_t>(Field) | OffsetOfNode::Field) {}
 
   /// Create an offsetof node that refers to an identifier.
   OffsetOfNode(SourceLocation DotLoc, IdentifierInfo *Name,
                SourceLocation NameLoc)
       : Range(DotLoc.isValid() ? DotLoc : NameLoc, NameLoc),
         Data(reinterpret_cast<uintptr_t>(Name) | Identifier) {}
 
   /// Create an offsetof node that refers into a C++ base class.
   explicit OffsetOfNode(const CXXBaseSpecifier *Base)
       : Data(reinterpret_cast<uintptr_t>(Base) | OffsetOfNode::Base) {}
 
   /// Determine what kind of offsetof node this is.
   Kind getKind() const { return static_cast<Kind>(Data & Mask); }
 
   /// For an array element node, returns the index into the array
   /// of expressions.
   unsigned getArrayExprIndex() const {
     assert(getKind() == Array);
     return Data >> 2;
   }
 
   /// For a field offsetof node, returns the field.
   FieldDecl *getField() const {
     assert(getKind() == Field);
     return reinterpret_cast<FieldDecl *>(Data & ~(uintptr_t)Mask);
   }
 
   /// For a field or identifier offsetof node, returns the name of
   /// the field.
   IdentifierInfo *getFieldName() const;
 
   /// For a base class node, returns the base specifier.
   CXXBaseSpecifier *getBase() const {
     assert(getKind() == Base);
     return reinterpret_cast<CXXBaseSpecifier *>(Data & ~(uintptr_t)Mask);
   }
 
   /// Retrieve the source range that covers this offsetof node.
   ///
   /// For an array element node, the source range contains the locations of
   /// the square brackets. For a field or identifier node, the source range
   /// contains the location of the period (if there is one) and the
   /// identifier.
   SourceRange getSourceRange() const LLVM_READONLY { return Range; }
   SourceLocation getBeginLoc() const LLVM_READONLY { return Range.getBegin(); }
   SourceLocation getEndLoc() const LLVM_READONLY { return Range.getEnd(); }
 };
 
 /// OffsetOfExpr - [C99 7.17] - This represents an expression of the form
 /// offsetof(record-type, member-designator). For example, given:
 /// @code
 /// struct S {
 ///   float f;
 ///   double d;
 /// };
 /// struct T {
 ///   int i;
 ///   struct S s[10];
 /// };
 /// @endcode
 /// we can represent and evaluate the expression @c offsetof(struct T, s[2].d).
 
 class OffsetOfExpr final
     : public Expr,
       private llvm::TrailingObjects<OffsetOfExpr, OffsetOfNode, Expr *> {
   SourceLocation OperatorLoc, RParenLoc;
   // Base type;
   TypeSourceInfo *TSInfo;
   // Number of sub-components (i.e. instances of OffsetOfNode).
   unsigned NumComps;
   // Number of sub-expressions (i.e. array subscript expressions).
   unsigned NumExprs;
 
   size_t numTrailingObjects(OverloadToken<OffsetOfNode>) const {
     return NumComps;
   }
 
   OffsetOfExpr(const ASTContext &C, QualType type,
                SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                ArrayRef<OffsetOfNode> comps, ArrayRef<Expr*> exprs,
                SourceLocation RParenLoc);
 
   explicit OffsetOfExpr(unsigned numComps, unsigned numExprs)
     : Expr(OffsetOfExprClass, EmptyShell()),
       TSInfo(nullptr), NumComps(numComps), NumExprs(numExprs) {}
 
 public:
 
   static OffsetOfExpr *Create(const ASTContext &C, QualType type,
                               SourceLocation OperatorLoc, TypeSourceInfo *tsi,
                               ArrayRef<OffsetOfNode> comps,
                               ArrayRef<Expr*> exprs, SourceLocation RParenLoc);
 
   static OffsetOfExpr *CreateEmpty(const ASTContext &C,
                                    unsigned NumComps, unsigned NumExprs);
 
   /// getOperatorLoc - Return the location of the operator.
   SourceLocation getOperatorLoc() const { return OperatorLoc; }
   void setOperatorLoc(SourceLocation L) { OperatorLoc = L; }
 
   /// Return the location of the right parentheses.
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation R) { RParenLoc = R; }
 
   TypeSourceInfo *getTypeSourceInfo() const {
     return TSInfo;
   }
   void setTypeSourceInfo(TypeSourceInfo *tsi) {
     TSInfo = tsi;
   }
 
   const OffsetOfNode &getComponent(unsigned Idx) const {
     assert(Idx < NumComps && "Subscript out of range");
     return getTrailingObjects<OffsetOfNode>()[Idx];
   }
 
   void setComponent(unsigned Idx, OffsetOfNode ON) {
     assert(Idx < NumComps && "Subscript out of range");
     getTrailingObjects<OffsetOfNode>()[Idx] = ON;
   }
 
   unsigned getNumComponents() const {
     return NumComps;
   }
 
   Expr* getIndexExpr(unsigned Idx) {
     assert(Idx < NumExprs && "Subscript out of range");
     return getTrailingObjects<Expr *>()[Idx];
   }
 
   const Expr *getIndexExpr(unsigned Idx) const {
     assert(Idx < NumExprs && "Subscript out of range");
     return getTrailingObjects<Expr *>()[Idx];
   }
 
   void setIndexExpr(unsigned Idx, Expr* E) {
     assert(Idx < NumComps && "Subscript out of range");
     getTrailingObjects<Expr *>()[Idx] = E;
   }
 
   unsigned getNumExpressions() const {
     return NumExprs;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return OperatorLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == OffsetOfExprClass;
   }
 
   // Iterators
   child_range children() {
     Stmt **begin = reinterpret_cast<Stmt **>(getTrailingObjects<Expr *>());
     return child_range(begin, begin + NumExprs);
   }
   const_child_range children() const {
     Stmt *const *begin =
         reinterpret_cast<Stmt *const *>(getTrailingObjects<Expr *>());
     return const_child_range(begin, begin + NumExprs);
   }
   friend TrailingObjects;
 };
 
 /// UnaryExprOrTypeTraitExpr - expression with either a type or (unevaluated)
 /// expression operand.  Used for sizeof/alignof (C99 6.5.3.4) and
 /// vec_step (OpenCL 1.1 6.11.12).
 class UnaryExprOrTypeTraitExpr : public Expr {
   union {
     TypeSourceInfo *Ty;
     Stmt *Ex;
   } Argument;
   SourceLocation OpLoc, RParenLoc;
 
 public:
   UnaryExprOrTypeTraitExpr(UnaryExprOrTypeTrait ExprKind, TypeSourceInfo *TInfo,
                            QualType resultType, SourceLocation op,
                            SourceLocation rp)
       : Expr(UnaryExprOrTypeTraitExprClass, resultType, VK_PRValue,
              OK_Ordinary),
         OpLoc(op), RParenLoc(rp) {
     assert(ExprKind <= UETT_Last && "invalid enum value!");
     UnaryExprOrTypeTraitExprBits.Kind = ExprKind;
     assert(static_cast<unsigned>(ExprKind) ==
                UnaryExprOrTypeTraitExprBits.Kind &&
            "UnaryExprOrTypeTraitExprBits.Kind overflow!");
     UnaryExprOrTypeTraitExprBits.IsType = true;
     Argument.Ty = TInfo;
     setDependence(computeDependence(this));
   }
 
   UnaryExprOrTypeTraitExpr(UnaryExprOrTypeTrait ExprKind, Expr *E,
                            QualType resultType, SourceLocation op,
                            SourceLocation rp);
 
   /// Construct an empty sizeof/alignof expression.
   explicit UnaryExprOrTypeTraitExpr(EmptyShell Empty)
     : Expr(UnaryExprOrTypeTraitExprClass, Empty) { }
 
   UnaryExprOrTypeTrait getKind() const {
     return static_cast<UnaryExprOrTypeTrait>(UnaryExprOrTypeTraitExprBits.Kind);
   }
   void setKind(UnaryExprOrTypeTrait K) {
     assert(K <= UETT_Last && "invalid enum value!");
     UnaryExprOrTypeTraitExprBits.Kind = K;
     assert(static_cast<unsigned>(K) == UnaryExprOrTypeTraitExprBits.Kind &&
            "UnaryExprOrTypeTraitExprBits.Kind overflow!");
   }
 
   bool isArgumentType() const { return UnaryExprOrTypeTraitExprBits.IsType; }
   QualType getArgumentType() const {
     return getArgumentTypeInfo()->getType();
   }
   TypeSourceInfo *getArgumentTypeInfo() const {
     assert(isArgumentType() && "calling getArgumentType() when arg is expr");
     return Argument.Ty;
   }
   Expr *getArgumentExpr() {
     assert(!isArgumentType() && "calling getArgumentExpr() when arg is type");
     return static_cast<Expr*>(Argument.Ex);
   }
   const Expr *getArgumentExpr() const {
     return const_cast<UnaryExprOrTypeTraitExpr*>(this)->getArgumentExpr();
   }
 
   void setArgument(Expr *E) {
     Argument.Ex = E;
     UnaryExprOrTypeTraitExprBits.IsType = false;
   }
   void setArgument(TypeSourceInfo *TInfo) {
     Argument.Ty = TInfo;
     UnaryExprOrTypeTraitExprBits.IsType = true;
   }
 
   /// Gets the argument type, or the type of the argument expression, whichever
   /// is appropriate.
   QualType getTypeOfArgument() const {
     return isArgumentType() ? getArgumentType() : getArgumentExpr()->getType();
   }
 
   SourceLocation getOperatorLoc() const { return OpLoc; }
   void setOperatorLoc(SourceLocation L) { OpLoc = L; }
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return OpLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == UnaryExprOrTypeTraitExprClass;
   }
 
   // Iterators
   child_range children();
   const_child_range children() const;
 };
 
 //===----------------------------------------------------------------------===//
 // Postfix Operators.
 //===----------------------------------------------------------------------===//
 
 /// ArraySubscriptExpr - [C99 6.5.2.1] Array Subscripting.
 class ArraySubscriptExpr : public Expr {
   enum { LHS, RHS, END_EXPR };
   Stmt *SubExprs[END_EXPR];
 
   bool lhsIsBase() const { return getRHS()->getType()->isIntegerType(); }
 
 public:
   ArraySubscriptExpr(Expr *lhs, Expr *rhs, QualType t, ExprValueKind VK,
                      ExprObjectKind OK, SourceLocation rbracketloc)
       : Expr(ArraySubscriptExprClass, t, VK, OK) {
     SubExprs[LHS] = lhs;
     SubExprs[RHS] = rhs;
     ArrayOrMatrixSubscriptExprBits.RBracketLoc = rbracketloc;
     setDependence(computeDependence(this));
   }
 
   /// Create an empty array subscript expression.
   explicit ArraySubscriptExpr(EmptyShell Shell)
     : Expr(ArraySubscriptExprClass, Shell) { }
 
   /// An array access can be written A[4] or 4[A] (both are equivalent).
   /// - getBase() and getIdx() always present the normalized view: A[4].
   ///    In this case getBase() returns "A" and getIdx() returns "4".
   /// - getLHS() and getRHS() present the syntactic view. e.g. for
   ///    4[A] getLHS() returns "4".
   /// Note: Because vector element access is also written A[4] we must
   /// predicate the format conversion in getBase and getIdx only on the
   /// the type of the RHS, as it is possible for the LHS to be a vector of
   /// integer type
   Expr *getLHS() { return cast<Expr>(SubExprs[LHS]); }
   const Expr *getLHS() const { return cast<Expr>(SubExprs[LHS]); }
   void setLHS(Expr *E) { SubExprs[LHS] = E; }
 
   Expr *getRHS() { return cast<Expr>(SubExprs[RHS]); }
   const Expr *getRHS() const { return cast<Expr>(SubExprs[RHS]); }
   void setRHS(Expr *E) { SubExprs[RHS] = E; }
 
   Expr *getBase() { return lhsIsBase() ? getLHS() : getRHS(); }
   const Expr *getBase() const { return lhsIsBase() ? getLHS() : getRHS(); }
 
   Expr *getIdx() { return lhsIsBase() ? getRHS() : getLHS(); }
   const Expr *getIdx() const { return lhsIsBase() ? getRHS() : getLHS(); }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getLHS()->getBeginLoc();
   }
   SourceLocation getEndLoc() const { return getRBracketLoc(); }
 
   SourceLocation getRBracketLoc() const {
     return ArrayOrMatrixSubscriptExprBits.RBracketLoc;
   }
   void setRBracketLoc(SourceLocation L) {
     ArrayOrMatrixSubscriptExprBits.RBracketLoc = L;
   }
 
   SourceLocation getExprLoc() const LLVM_READONLY {
     return getBase()->getExprLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ArraySubscriptExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0]+END_EXPR);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
 };
 
 /// MatrixSubscriptExpr - Matrix subscript expression for the MatrixType
 /// extension.
 /// MatrixSubscriptExpr can be either incomplete (only Base and RowIdx are set
 /// so far, the type is IncompleteMatrixIdx) or complete (Base, RowIdx and
 /// ColumnIdx refer to valid expressions). Incomplete matrix expressions only
 /// exist during the initial construction of the AST.
 class MatrixSubscriptExpr : public Expr {
   enum { BASE, ROW_IDX, COLUMN_IDX, END_EXPR };
   Stmt *SubExprs[END_EXPR];
 
 public:
   MatrixSubscriptExpr(Expr *Base, Expr *RowIdx, Expr *ColumnIdx, QualType T,
                       SourceLocation RBracketLoc)
       : Expr(MatrixSubscriptExprClass, T, Base->getValueKind(),
              OK_MatrixComponent) {
     SubExprs[BASE] = Base;
     SubExprs[ROW_IDX] = RowIdx;
     SubExprs[COLUMN_IDX] = ColumnIdx;
     ArrayOrMatrixSubscriptExprBits.RBracketLoc = RBracketLoc;
     setDependence(computeDependence(this));
   }
 
   /// Create an empty matrix subscript expression.
   explicit MatrixSubscriptExpr(EmptyShell Shell)
       : Expr(MatrixSubscriptExprClass, Shell) {}
 
   bool isIncomplete() const {
     bool IsIncomplete = hasPlaceholderType(BuiltinType::IncompleteMatrixIdx);
     assert((SubExprs[COLUMN_IDX] || IsIncomplete) &&
            "expressions without column index must be marked as incomplete");
     return IsIncomplete;
   }
   Expr *getBase() { return cast<Expr>(SubExprs[BASE]); }
   const Expr *getBase() const { return cast<Expr>(SubExprs[BASE]); }
   void setBase(Expr *E) { SubExprs[BASE] = E; }
 
   Expr *getRowIdx() { return cast<Expr>(SubExprs[ROW_IDX]); }
   const Expr *getRowIdx() const { return cast<Expr>(SubExprs[ROW_IDX]); }
   void setRowIdx(Expr *E) { SubExprs[ROW_IDX] = E; }
 
   Expr *getColumnIdx() { return cast_or_null<Expr>(SubExprs[COLUMN_IDX]); }
   const Expr *getColumnIdx() const {
     assert(!isIncomplete() &&
            "cannot get the column index of an incomplete expression");
     return cast<Expr>(SubExprs[COLUMN_IDX]);
   }
   void setColumnIdx(Expr *E) { SubExprs[COLUMN_IDX] = E; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getBase()->getBeginLoc();
   }
 
   SourceLocation getEndLoc() const { return getRBracketLoc(); }
 
   SourceLocation getExprLoc() const LLVM_READONLY {
     return getBase()->getExprLoc();
   }
 
   SourceLocation getRBracketLoc() const {
     return ArrayOrMatrixSubscriptExprBits.RBracketLoc;
   }
   void setRBracketLoc(SourceLocation L) {
     ArrayOrMatrixSubscriptExprBits.RBracketLoc = L;
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == MatrixSubscriptExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
 };
 
 /// CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
 /// CallExpr itself represents a normal function call, e.g., "f(x, 2)",
 /// while its subclasses may represent alternative syntax that (semantically)
 /// results in a function call. For example, CXXOperatorCallExpr is
 /// a subclass for overloaded operator calls that use operator syntax, e.g.,
 /// "str1 + str2" to resolve to a function call.
 class CallExpr : public Expr {
   enum { FN = 0, PREARGS_START = 1 };
 
   /// The number of arguments in the call expression.
   unsigned NumArgs;
 
   /// The location of the right parentheses. This has a different meaning for
   /// the derived classes of CallExpr.
   SourceLocation RParenLoc;
 
   // CallExpr store some data in trailing objects. However since CallExpr
   // is used a base of other expression classes we cannot use
   // llvm::TrailingObjects. Instead we manually perform the pointer arithmetic
   // and casts.
   //
   // The trailing objects are in order:
   //
   // * A single "Stmt *" for the callee expression.
   //
   // * An array of getNumPreArgs() "Stmt *" for the pre-argument expressions.
   //
   // * An array of getNumArgs() "Stmt *" for the argument expressions.
   //
   // * An optional of type FPOptionsOverride.
   //
   // Note that we store the offset in bytes from the this pointer to the start
   // of the trailing objects. It would be perfectly possible to compute it
   // based on the dynamic kind of the CallExpr. However 1.) we have plenty of
   // space in the bit-fields of Stmt. 2.) It was benchmarked to be faster to
   // compute this once and then load the offset from the bit-fields of Stmt,
   // instead of re-computing the offset each time the trailing objects are
   // accessed.
 
   /// Return a pointer to the start of the trailing array of "Stmt *".
   Stmt **getTrailingStmts() {
     return reinterpret_cast<Stmt **>(reinterpret_cast<char *>(this) +
                                      CallExprBits.OffsetToTrailingObjects);
   }
   Stmt *const *getTrailingStmts() const {
     return const_cast<CallExpr *>(this)->getTrailingStmts();
   }
 
   /// Map a statement class to the appropriate offset in bytes from the
   /// this pointer to the trailing objects.
   static unsigned offsetToTrailingObjects(StmtClass SC);
 
   unsigned getSizeOfTrailingStmts() const {
     return (1 + getNumPreArgs() + getNumArgs()) * sizeof(Stmt *);
   }
 
   size_t getOffsetOfTrailingFPFeatures() const {
     assert(hasStoredFPFeatures());
     return CallExprBits.OffsetToTrailingObjects + getSizeOfTrailingStmts();
   }
 
 public:
   enum class ADLCallKind : bool { NotADL, UsesADL };
   static constexpr ADLCallKind NotADL = ADLCallKind::NotADL;
   static constexpr ADLCallKind UsesADL = ADLCallKind::UsesADL;
 
 protected:
   /// Build a call expression, assuming that appropriate storage has been
   /// allocated for the trailing objects.
   CallExpr(StmtClass SC, Expr *Fn, ArrayRef<Expr *> PreArgs,
            ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
            SourceLocation RParenLoc, FPOptionsOverride FPFeatures,
            unsigned MinNumArgs, ADLCallKind UsesADL);
 
   /// Build an empty call expression, for deserialization.
   CallExpr(StmtClass SC, unsigned NumPreArgs, unsigned NumArgs,
            bool hasFPFeatures, EmptyShell Empty);
 
   /// Return the size in bytes needed for the trailing objects.
   /// Used by the derived classes to allocate the right amount of storage.
   static unsigned sizeOfTrailingObjects(unsigned NumPreArgs, unsigned NumArgs,
                                         bool HasFPFeatures) {
     return (1 + NumPreArgs + NumArgs) * sizeof(Stmt *) +
            HasFPFeatures * sizeof(FPOptionsOverride);
   }
 
   Stmt *getPreArg(unsigned I) {
     assert(I < getNumPreArgs() && "Prearg access out of range!");
     return getTrailingStmts()[PREARGS_START + I];
   }
   const Stmt *getPreArg(unsigned I) const {
     assert(I < getNumPreArgs() && "Prearg access out of range!");
     return getTrailingStmts()[PREARGS_START + I];
   }
   void setPreArg(unsigned I, Stmt *PreArg) {
     assert(I < getNumPreArgs() && "Prearg access out of range!");
     getTrailingStmts()[PREARGS_START + I] = PreArg;
   }
 
   unsigned getNumPreArgs() const { return CallExprBits.NumPreArgs; }
 
   /// Return a pointer to the trailing FPOptions
   FPOptionsOverride *getTrailingFPFeatures() {
     assert(hasStoredFPFeatures());
     return reinterpret_cast<FPOptionsOverride *>(
         reinterpret_cast<char *>(this) + CallExprBits.OffsetToTrailingObjects +
         getSizeOfTrailingStmts());
   }
   const FPOptionsOverride *getTrailingFPFeatures() const {
     assert(hasStoredFPFeatures());
     return reinterpret_cast<const FPOptionsOverride *>(
         reinterpret_cast<const char *>(this) +
         CallExprBits.OffsetToTrailingObjects + getSizeOfTrailingStmts());
   }
 
 public:
   /// Create a call expression.
   /// \param Fn     The callee expression,
   /// \param Args   The argument array,
   /// \param Ty     The type of the call expression (which is *not* the return
   ///               type in general),
   /// \param VK     The value kind of the call expression (lvalue, rvalue, ...),
   /// \param RParenLoc  The location of the right parenthesis in the call
   ///                   expression.
   /// \param FPFeatures Floating-point features associated with the call,
   /// \param MinNumArgs Specifies the minimum number of arguments. The actual
   ///                   number of arguments will be the greater of Args.size()
   ///                   and MinNumArgs. This is used in a few places to allocate
   ///                   enough storage for the default arguments.
   /// \param UsesADL    Specifies whether the callee was found through
   ///                   argument-dependent lookup.
   ///
   /// Note that you can use CreateTemporary if you need a temporary call
   /// expression on the stack.
   static CallExpr *Create(const ASTContext &Ctx, Expr *Fn,
                           ArrayRef<Expr *> Args, QualType Ty, ExprValueKind VK,
                           SourceLocation RParenLoc,
                           FPOptionsOverride FPFeatures, unsigned MinNumArgs = 0,
                           ADLCallKind UsesADL = NotADL);
 
   /// Create a temporary call expression with no arguments in the memory
   /// pointed to by Mem. Mem must points to at least sizeof(CallExpr)
   /// + sizeof(Stmt *) bytes of storage, aligned to alignof(CallExpr):
   ///
   /// \code{.cpp}
   ///   alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
   ///   CallExpr *TheCall = CallExpr::CreateTemporary(Buffer, etc);
   /// \endcode
   static CallExpr *CreateTemporary(void *Mem, Expr *Fn, QualType Ty,
                                    ExprValueKind VK, SourceLocation RParenLoc,
                                    ADLCallKind UsesADL = NotADL);
 
   /// Create an empty call expression, for deserialization.
   static CallExpr *CreateEmpty(const ASTContext &Ctx, unsigned NumArgs,
                                bool HasFPFeatures, EmptyShell Empty);
 
   Expr *getCallee() { return cast<Expr>(getTrailingStmts()[FN]); }
   const Expr *getCallee() const { return cast<Expr>(getTrailingStmts()[FN]); }
   void setCallee(Expr *F) { getTrailingStmts()[FN] = F; }
 
   ADLCallKind getADLCallKind() const {
     return static_cast<ADLCallKind>(CallExprBits.UsesADL);
   }
   void setADLCallKind(ADLCallKind V = UsesADL) {
     CallExprBits.UsesADL = static_cast<bool>(V);
   }
   bool usesADL() const { return getADLCallKind() == UsesADL; }
 
   bool hasStoredFPFeatures() const { return CallExprBits.HasFPFeatures; }
 
   bool isCoroElideSafe() const { return CallExprBits.IsCoroElideSafe; }
   void setCoroElideSafe(bool V = true) { CallExprBits.IsCoroElideSafe = V; }
 
   Decl *getCalleeDecl() { return getCallee()->getReferencedDeclOfCallee(); }
   const Decl *getCalleeDecl() const {
     return getCallee()->getReferencedDeclOfCallee();
   }
 
   /// If the callee is a FunctionDecl, return it. Otherwise return null.
   FunctionDecl *getDirectCallee() {
     return dyn_cast_or_null<FunctionDecl>(getCalleeDecl());
   }
   const FunctionDecl *getDirectCallee() const {
     return dyn_cast_or_null<FunctionDecl>(getCalleeDecl());
   }
 
   /// getNumArgs - Return the number of actual arguments to this call.
   unsigned getNumArgs() const { return NumArgs; }
 
   /// Retrieve the call arguments.
   Expr **getArgs() {
     return reinterpret_cast<Expr **>(getTrailingStmts() + PREARGS_START +
                                      getNumPreArgs());
   }
   const Expr *const *getArgs() const {
     return reinterpret_cast<const Expr *const *>(
         getTrailingStmts() + PREARGS_START + getNumPreArgs());
   }
 
   /// getArg - Return the specified argument.
   Expr *getArg(unsigned Arg) {
     assert(Arg < getNumArgs() && "Arg access out of range!");
     return getArgs()[Arg];
   }
   const Expr *getArg(unsigned Arg) const {
     assert(Arg < getNumArgs() && "Arg access out of range!");
     return getArgs()[Arg];
   }
 
   /// setArg - Set the specified argument.
   /// ! the dependence bits might be stale after calling this setter, it is
   /// *caller*'s responsibility to recompute them by calling
   /// computeDependence().
   void setArg(unsigned Arg, Expr *ArgExpr) {
     assert(Arg < getNumArgs() && "Arg access out of range!");
     getArgs()[Arg] = ArgExpr;
   }
 
   /// Compute and set dependence bits.
   void computeDependence() {
     setDependence(clang::computeDependence(
         this, llvm::ArrayRef(
                   reinterpret_cast<Expr **>(getTrailingStmts() + PREARGS_START),
                   getNumPreArgs())));
   }
 
   /// Reduce the number of arguments in this call expression. This is used for
   /// example during error recovery to drop extra arguments. There is no way
   /// to perform the opposite because: 1.) We don't track how much storage
   /// we have for the argument array 2.) This would potentially require growing
   /// the argument array, something we cannot support since the arguments are
   /// stored in a trailing array.
   void shrinkNumArgs(unsigned NewNumArgs) {
     assert((NewNumArgs <= getNumArgs()) &&
            "shrinkNumArgs cannot increase the number of arguments!");
     NumArgs = NewNumArgs;
   }
 
   /// Bluntly set a new number of arguments without doing any checks whatsoever.
   /// Only used during construction of a CallExpr in a few places in Sema.
   /// FIXME: Find a way to remove it.
   void setNumArgsUnsafe(unsigned NewNumArgs) { NumArgs = NewNumArgs; }
 
   typedef ExprIterator arg_iterator;
   typedef ConstExprIterator const_arg_iterator;
   typedef llvm::iterator_range<arg_iterator> arg_range;
   typedef llvm::iterator_range<const_arg_iterator> const_arg_range;
 
   arg_range arguments() { return arg_range(arg_begin(), arg_end()); }
   const_arg_range arguments() const {
     return const_arg_range(arg_begin(), arg_end());
   }
 
   arg_iterator arg_begin() {
     return getTrailingStmts() + PREARGS_START + getNumPreArgs();
   }
   arg_iterator arg_end() { return arg_begin() + getNumArgs(); }
 
   const_arg_iterator arg_begin() const {
     return getTrailingStmts() + PREARGS_START + getNumPreArgs();
   }
   const_arg_iterator arg_end() const { return arg_begin() + getNumArgs(); }
 
   /// This method provides fast access to all the subexpressions of
   /// a CallExpr without going through the slower virtual child_iterator
   /// interface.  This provides efficient reverse iteration of the
   /// subexpressions.  This is currently used for CFG construction.
   ArrayRef<Stmt *> getRawSubExprs() {
     return llvm::ArrayRef(getTrailingStmts(),
                           PREARGS_START + getNumPreArgs() + getNumArgs());
   }
 
   /// Get FPOptionsOverride from trailing storage.
   FPOptionsOverride getStoredFPFeatures() const {
     assert(hasStoredFPFeatures());
     return *getTrailingFPFeatures();
   }
   /// Set FPOptionsOverride in trailing storage. Used only by Serialization.
   void setStoredFPFeatures(FPOptionsOverride F) {
     assert(hasStoredFPFeatures());
     *getTrailingFPFeatures() = F;
   }
 
   /// Get the store FPOptionsOverride or default if not stored.
   FPOptionsOverride getStoredFPFeaturesOrDefault() const {
     return hasStoredFPFeatures() ? getStoredFPFeatures() : FPOptionsOverride();
   }
 
   /// Get the FP features status of this operator. Only meaningful for
   /// operations on floating point types.
   FPOptions getFPFeaturesInEffect(const LangOptions &LO) const {
     if (hasStoredFPFeatures())
       return getStoredFPFeatures().applyOverrides(LO);
     return FPOptions::defaultWithoutTrailingStorage(LO);
   }
 
   FPOptionsOverride getFPFeatures() const {
     if (hasStoredFPFeatures())
       return getStoredFPFeatures();
     return FPOptionsOverride();
   }
 
   /// getBuiltinCallee - If this is a call to a builtin, return the builtin ID
   /// of the callee. If not, return 0.
   unsigned getBuiltinCallee() const;
 
   /// Returns \c true if this is a call to a builtin which does not
   /// evaluate side-effects within its arguments.
   bool isUnevaluatedBuiltinCall(const ASTContext &Ctx) const;
 
   /// getCallReturnType - Get the return type of the call expr. This is not
   /// always the type of the expr itself, if the return type is a reference
   /// type.
   QualType getCallReturnType(const ASTContext &Ctx) const;
 
   /// Returns the WarnUnusedResultAttr that is either declared on the called
   /// function, or its return type declaration, together with a NamedDecl that
   /// refers to the declaration the attribute is attached onto.
   std::pair<const NamedDecl *, const Attr *>
   getUnusedResultAttr(const ASTContext &Ctx) const;
 
   /// Returns true if this call expression should warn on unused results.
   bool hasUnusedResultAttr(const ASTContext &Ctx) const {
     return getUnusedResultAttr(Ctx).second != nullptr;
   }
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   /// Return true if this is a call to __assume() or __builtin_assume() with
   /// a non-value-dependent constant parameter evaluating as false.
   bool isBuiltinAssumeFalse(const ASTContext &Ctx) const;
 
   /// Used by Sema to implement MSVC-compatible delayed name lookup.
   /// (Usually Exprs themselves should set dependence).
   void markDependentForPostponedNameLookup() {
     setDependence(getDependence() | ExprDependence::TypeValueInstantiation);
   }
 
   bool isCallToStdMove() const;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() >= firstCallExprConstant &&
            T->getStmtClass() <= lastCallExprConstant;
   }
 
   // Iterators
   child_range children() {
     return child_range(getTrailingStmts(), getTrailingStmts() + PREARGS_START +
                                                getNumPreArgs() + getNumArgs());
   }
 
   const_child_range children() const {
     return const_child_range(getTrailingStmts(),
                              getTrailingStmts() + PREARGS_START +
                                  getNumPreArgs() + getNumArgs());
   }
 };
 
 /// MemberExpr - [C99 6.5.2.3] Structure and Union Members.  X->F and X.F.
 ///
 class MemberExpr final
     : public Expr,
       private llvm::TrailingObjects<MemberExpr, NestedNameSpecifierLoc,
                                     DeclAccessPair, ASTTemplateKWAndArgsInfo,
                                     TemplateArgumentLoc> {
   friend class ASTReader;
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
   friend TrailingObjects;
 
   /// Base - the expression for the base pointer or structure references.  In
   /// X.F, this is "X".
   Stmt *Base;
 
   /// MemberDecl - This is the decl being referenced by the field/member name.
   /// In X.F, this is the decl referenced by F.
   ValueDecl *MemberDecl;
 
   /// MemberDNLoc - Provides source/type location info for the
   /// declaration name embedded in MemberDecl.
   DeclarationNameLoc MemberDNLoc;
 
   /// MemberLoc - This is the location of the member name.
   SourceLocation MemberLoc;
 
   size_t numTrailingObjects(OverloadToken<NestedNameSpecifierLoc>) const {
     return hasQualifier();
   }
 
   size_t numTrailingObjects(OverloadToken<DeclAccessPair>) const {
     return hasFoundDecl();
   }
 
   size_t numTrailingObjects(OverloadToken<ASTTemplateKWAndArgsInfo>) const {
     return hasTemplateKWAndArgsInfo();
   }
 
   bool hasFoundDecl() const { return MemberExprBits.HasFoundDecl; }
 
   bool hasTemplateKWAndArgsInfo() const {
     return MemberExprBits.HasTemplateKWAndArgsInfo;
   }
 
   MemberExpr(Expr *Base, bool IsArrow, SourceLocation OperatorLoc,
              NestedNameSpecifierLoc QualifierLoc, SourceLocation TemplateKWLoc,
              ValueDecl *MemberDecl, DeclAccessPair FoundDecl,
              const DeclarationNameInfo &NameInfo,
              const TemplateArgumentListInfo *TemplateArgs, QualType T,
              ExprValueKind VK, ExprObjectKind OK, NonOdrUseReason NOUR);
   MemberExpr(EmptyShell Empty)
       : Expr(MemberExprClass, Empty), Base(), MemberDecl() {}
 
 public:
   static MemberExpr *Create(const ASTContext &C, Expr *Base, bool IsArrow,
                             SourceLocation OperatorLoc,
                             NestedNameSpecifierLoc QualifierLoc,
                             SourceLocation TemplateKWLoc, ValueDecl *MemberDecl,
                             DeclAccessPair FoundDecl,
                             DeclarationNameInfo MemberNameInfo,
                             const TemplateArgumentListInfo *TemplateArgs,
                             QualType T, ExprValueKind VK, ExprObjectKind OK,
                             NonOdrUseReason NOUR);
 
   /// Create an implicit MemberExpr, with no location, qualifier, template
   /// arguments, and so on. Suitable only for non-static member access.
   static MemberExpr *CreateImplicit(const ASTContext &C, Expr *Base,
                                     bool IsArrow, ValueDecl *MemberDecl,
                                     QualType T, ExprValueKind VK,
                                     ExprObjectKind OK) {
     return Create(C, Base, IsArrow, SourceLocation(), NestedNameSpecifierLoc(),
                   SourceLocation(), MemberDecl,
                   DeclAccessPair::make(MemberDecl, MemberDecl->getAccess()),
                   DeclarationNameInfo(), nullptr, T, VK, OK, NOUR_None);
   }
 
   static MemberExpr *CreateEmpty(const ASTContext &Context, bool HasQualifier,
                                  bool HasFoundDecl,
                                  bool HasTemplateKWAndArgsInfo,
                                  unsigned NumTemplateArgs);
 
   void setBase(Expr *E) { Base = E; }
   Expr *getBase() const { return cast<Expr>(Base); }
 
   /// Retrieve the member declaration to which this expression refers.
   ///
   /// The returned declaration will be a FieldDecl or (in C++) a VarDecl (for
   /// static data members), a CXXMethodDecl, or an EnumConstantDecl.
   ValueDecl *getMemberDecl() const { return MemberDecl; }
   void setMemberDecl(ValueDecl *D);
 
   /// Retrieves the declaration found by lookup.
   DeclAccessPair getFoundDecl() const {
     if (!hasFoundDecl())
       return DeclAccessPair::make(getMemberDecl(),
                                   getMemberDecl()->getAccess());
     return *getTrailingObjects<DeclAccessPair>();
   }
 
   /// Determines whether this member expression actually had
   /// a C++ nested-name-specifier prior to the name of the member, e.g.,
   /// x->Base::foo.
   bool hasQualifier() const { return MemberExprBits.HasQualifier; }
 
   /// If the member name was qualified, retrieves the
   /// nested-name-specifier that precedes the member name, with source-location
   /// information.
   NestedNameSpecifierLoc getQualifierLoc() const {
     if (!hasQualifier())
       return NestedNameSpecifierLoc();
     return *getTrailingObjects<NestedNameSpecifierLoc>();
   }
 
   /// If the member name was qualified, retrieves the
   /// nested-name-specifier that precedes the member name. Otherwise, returns
   /// NULL.
   NestedNameSpecifier *getQualifier() const {
     return getQualifierLoc().getNestedNameSpecifier();
   }
 
   /// Retrieve the location of the template keyword preceding
   /// the member name, if any.
   SourceLocation getTemplateKeywordLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->TemplateKWLoc;
   }
 
   /// Retrieve the location of the left angle bracket starting the
   /// explicit template argument list following the member name, if any.
   SourceLocation getLAngleLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->LAngleLoc;
   }
 
   /// Retrieve the location of the right angle bracket ending the
   /// explicit template argument list following the member name, if any.
   SourceLocation getRAngleLoc() const {
     if (!hasTemplateKWAndArgsInfo())
       return SourceLocation();
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->RAngleLoc;
   }
 
   /// Determines whether the member name was preceded by the template keyword.
   bool hasTemplateKeyword() const { return getTemplateKeywordLoc().isValid(); }
 
   /// Determines whether the member name was followed by an
   /// explicit template argument list.
   bool hasExplicitTemplateArgs() const { return getLAngleLoc().isValid(); }
 
   /// Copies the template arguments (if present) into the given
   /// structure.
   void copyTemplateArgumentsInto(TemplateArgumentListInfo &List) const {
     if (hasExplicitTemplateArgs())
       getTrailingObjects<ASTTemplateKWAndArgsInfo>()->copyInto(
           getTrailingObjects<TemplateArgumentLoc>(), List);
   }
 
   /// Retrieve the template arguments provided as part of this
   /// template-id.
   const TemplateArgumentLoc *getTemplateArgs() const {
     if (!hasExplicitTemplateArgs())
       return nullptr;
 
     return getTrailingObjects<TemplateArgumentLoc>();
   }
 
   /// Retrieve the number of template arguments provided as part of this
   /// template-id.
   unsigned getNumTemplateArgs() const {
     if (!hasExplicitTemplateArgs())
       return 0;
 
     return getTrailingObjects<ASTTemplateKWAndArgsInfo>()->NumTemplateArgs;
   }
 
   ArrayRef<TemplateArgumentLoc> template_arguments() const {
     return {getTemplateArgs(), getNumTemplateArgs()};
   }
 
   /// Retrieve the member declaration name info.
   DeclarationNameInfo getMemberNameInfo() const {
     return DeclarationNameInfo(MemberDecl->getDeclName(),
                                MemberLoc, MemberDNLoc);
   }
 
   SourceLocation getOperatorLoc() const { return MemberExprBits.OperatorLoc; }
 
   bool isArrow() const { return MemberExprBits.IsArrow; }
   void setArrow(bool A) { MemberExprBits.IsArrow = A; }
 
   /// getMemberLoc - Return the location of the "member", in X->F, it is the
   /// location of 'F'.
   SourceLocation getMemberLoc() const { return MemberLoc; }
   void setMemberLoc(SourceLocation L) { MemberLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   SourceLocation getExprLoc() const LLVM_READONLY { return MemberLoc; }
 
   /// Determine whether the base of this explicit is implicit.
   bool isImplicitAccess() const {
     return getBase() && getBase()->isImplicitCXXThis();
   }
 
   /// Returns true if this member expression refers to a method that
   /// was resolved from an overloaded set having size greater than 1.
   bool hadMultipleCandidates() const {
     return MemberExprBits.HadMultipleCandidates;
   }
   /// Sets the flag telling whether this expression refers to
   /// a method that was resolved from an overloaded set having size
   /// greater than 1.
   void setHadMultipleCandidates(bool V = true) {
     MemberExprBits.HadMultipleCandidates = V;
   }
 
   /// Returns true if virtual dispatch is performed.
   /// If the member access is fully qualified, (i.e. X::f()), virtual
   /// dispatching is not performed. In -fapple-kext mode qualified
   /// calls to virtual method will still go through the vtable.
   bool performsVirtualDispatch(const LangOptions &LO) const {
     return LO.AppleKext || !hasQualifier();
   }
 
   /// Is this expression a non-odr-use reference, and if so, why?
   /// This is only meaningful if the named member is a static member.
   NonOdrUseReason isNonOdrUse() const {
     return static_cast<NonOdrUseReason>(MemberExprBits.NonOdrUseReason);
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == MemberExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Base, &Base+1); }
   const_child_range children() const {
     return const_child_range(&Base, &Base + 1);
   }
 };
 
 /// CompoundLiteralExpr - [C99 6.5.2.5]
 ///
 class CompoundLiteralExpr : public Expr {
   /// LParenLoc - If non-null, this is the location of the left paren in a
   /// compound literal like "(int){4}".  This can be null if this is a
   /// synthesized compound expression.
   SourceLocation LParenLoc;
 
   /// The type as written.  This can be an incomplete array type, in
   /// which case the actual expression type will be different.
   /// The int part of the pair stores whether this expr is file scope.
   llvm::PointerIntPair<TypeSourceInfo *, 1, bool> TInfoAndScope;
   Stmt *Init;
 public:
   CompoundLiteralExpr(SourceLocation lparenloc, TypeSourceInfo *tinfo,
                       QualType T, ExprValueKind VK, Expr *init, bool fileScope)
       : Expr(CompoundLiteralExprClass, T, VK, OK_Ordinary),
         LParenLoc(lparenloc), TInfoAndScope(tinfo, fileScope), Init(init) {
     setDependence(computeDependence(this));
   }
 
   /// Construct an empty compound literal.
   explicit CompoundLiteralExpr(EmptyShell Empty)
     : Expr(CompoundLiteralExprClass, Empty) { }
 
   const Expr *getInitializer() const { return cast<Expr>(Init); }
   Expr *getInitializer() { return cast<Expr>(Init); }
   void setInitializer(Expr *E) { Init = E; }
 
   bool isFileScope() const { return TInfoAndScope.getInt(); }
   void setFileScope(bool FS) { TInfoAndScope.setInt(FS); }
 
   SourceLocation getLParenLoc() const { return LParenLoc; }
   void setLParenLoc(SourceLocation L) { LParenLoc = L; }
 
   TypeSourceInfo *getTypeSourceInfo() const {
     return TInfoAndScope.getPointer();
   }
   void setTypeSourceInfo(TypeSourceInfo *tinfo) {
     TInfoAndScope.setPointer(tinfo);
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     // FIXME: Init should never be null.
     if (!Init)
       return SourceLocation();
     if (LParenLoc.isInvalid())
       return Init->getBeginLoc();
     return LParenLoc;
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     // FIXME: Init should never be null.
     if (!Init)
       return SourceLocation();
     return Init->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == CompoundLiteralExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Init, &Init+1); }
   const_child_range children() const {
     return const_child_range(&Init, &Init + 1);
   }
 };
 
 /// CastExpr - Base class for type casts, including both implicit
 /// casts (ImplicitCastExpr) and explicit casts that have some
 /// representation in the source code (ExplicitCastExpr's derived
 /// classes).
 class CastExpr : public Expr {
   Stmt *Op;
 
   bool CastConsistency() const;
 
   const CXXBaseSpecifier * const *path_buffer() const {
     return const_cast<CastExpr*>(this)->path_buffer();
   }
   CXXBaseSpecifier **path_buffer();
 
   friend class ASTStmtReader;
 
 protected:
   CastExpr(StmtClass SC, QualType ty, ExprValueKind VK, const CastKind kind,
            Expr *op, unsigned BasePathSize, bool HasFPFeatures)
       : Expr(SC, ty, VK, OK_Ordinary), Op(op) {
     CastExprBits.Kind = kind;
     CastExprBits.PartOfExplicitCast = false;
     CastExprBits.BasePathSize = BasePathSize;
     assert((CastExprBits.BasePathSize == BasePathSize) &&
            "BasePathSize overflow!");
     assert(CastConsistency());
     CastExprBits.HasFPFeatures = HasFPFeatures;
   }
 
   /// Construct an empty cast.
   CastExpr(StmtClass SC, EmptyShell Empty, unsigned BasePathSize,
            bool HasFPFeatures)
       : Expr(SC, Empty) {
     CastExprBits.PartOfExplicitCast = false;
     CastExprBits.BasePathSize = BasePathSize;
     CastExprBits.HasFPFeatures = HasFPFeatures;
     assert((CastExprBits.BasePathSize == BasePathSize) &&
            "BasePathSize overflow!");
   }
 
   /// Return a pointer to the trailing FPOptions.
   /// \pre hasStoredFPFeatures() == true
   FPOptionsOverride *getTrailingFPFeatures();
   const FPOptionsOverride *getTrailingFPFeatures() const {
     return const_cast<CastExpr *>(this)->getTrailingFPFeatures();
   }
 
 public:
   CastKind getCastKind() const { return (CastKind) CastExprBits.Kind; }
   void setCastKind(CastKind K) { CastExprBits.Kind = K; }
 
   static const char *getCastKindName(CastKind CK);
   const char *getCastKindName() const { return getCastKindName(getCastKind()); }
 
   Expr *getSubExpr() { return cast<Expr>(Op); }
   const Expr *getSubExpr() const { return cast<Expr>(Op); }
   void setSubExpr(Expr *E) { Op = E; }
 
   /// Retrieve the cast subexpression as it was written in the source
   /// code, looking through any implicit casts or other intermediate nodes
   /// introduced by semantic analysis.
   Expr *getSubExprAsWritten();
   const Expr *getSubExprAsWritten() const {
     return const_cast<CastExpr *>(this)->getSubExprAsWritten();
   }
 
   /// If this cast applies a user-defined conversion, retrieve the conversion
   /// function that it invokes.
   NamedDecl *getConversionFunction() const;
 
   typedef CXXBaseSpecifier **path_iterator;
   typedef const CXXBaseSpecifier *const *path_const_iterator;
   bool path_empty() const { return path_size() == 0; }
   unsigned path_size() const { return CastExprBits.BasePathSize; }
   path_iterator path_begin() { return path_buffer(); }
   path_iterator path_end() { return path_buffer() + path_size(); }
   path_const_iterator path_begin() const { return path_buffer(); }
   path_const_iterator path_end() const { return path_buffer() + path_size(); }
 
   /// Path through the class hierarchy taken by casts between base and derived
   /// classes (see implementation of `CastConsistency()` for a full list of
   /// cast kinds that have a path).
   ///
   /// For each derived-to-base edge in the path, the path contains a
   /// `CXXBaseSpecifier` for the base class of that edge; the entries are
   /// ordered from derived class to base class.
   ///
   /// For example, given classes `Base`, `Intermediate : public Base` and
   /// `Derived : public Intermediate`, the path for a cast from `Derived *` to
   /// `Base *` contains two entries: One for `Intermediate`, and one for `Base`,
   /// in that order.
   llvm::iterator_range<path_iterator> path() {
     return llvm::make_range(path_begin(), path_end());
   }
   llvm::iterator_range<path_const_iterator> path() const {
     return llvm::make_range(path_begin(), path_end());
   }
 
   const FieldDecl *getTargetUnionField() const {
     assert(getCastKind() == CK_ToUnion);
     return getTargetFieldForToUnionCast(getType(), getSubExpr()->getType());
   }
 
   bool hasStoredFPFeatures() const { return CastExprBits.HasFPFeatures; }
 
   /// Get FPOptionsOverride from trailing storage.
   FPOptionsOverride getStoredFPFeatures() const {
     assert(hasStoredFPFeatures());
     return *getTrailingFPFeatures();
   }
 
   /// Get the store FPOptionsOverride or default if not stored.
   FPOptionsOverride getStoredFPFeaturesOrDefault() const {
     return hasStoredFPFeatures() ? getStoredFPFeatures() : FPOptionsOverride();
   }
 
   /// Get the FP features status of this operation. Only meaningful for
   /// operations on floating point types.
   FPOptions getFPFeaturesInEffect(const LangOptions &LO) const {
     if (hasStoredFPFeatures())
       return getStoredFPFeatures().applyOverrides(LO);
     return FPOptions::defaultWithoutTrailingStorage(LO);
   }
 
   FPOptionsOverride getFPFeatures() const {
     if (hasStoredFPFeatures())
       return getStoredFPFeatures();
     return FPOptionsOverride();
   }
 
   /// Return
   //  True : if this conversion changes the volatile-ness of a gl-value.
   //         Qualification conversions on gl-values currently use CK_NoOp, but
   //         it's important to recognize volatile-changing conversions in
   //         clients code generation that normally eagerly peephole loads. Note
   //         that the query is answering for this specific node; Sema may
   //         produce multiple cast nodes for any particular conversion sequence.
   //  False : Otherwise.
   bool changesVolatileQualification() const {
     return (isGLValue() && (getType().isVolatileQualified() !=
                             getSubExpr()->getType().isVolatileQualified()));
   }
 
   static const FieldDecl *getTargetFieldForToUnionCast(QualType unionType,
                                                        QualType opType);
   static const FieldDecl *getTargetFieldForToUnionCast(const RecordDecl *RD,
                                                        QualType opType);
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() >= firstCastExprConstant &&
            T->getStmtClass() <= lastCastExprConstant;
   }
 
   // Iterators
   child_range children() { return child_range(&Op, &Op+1); }
   const_child_range children() const { return const_child_range(&Op, &Op + 1); }
 };
 
 /// ImplicitCastExpr - Allows us to explicitly represent implicit type
 /// conversions, which have no direct representation in the original
 /// source code. For example: converting T[]->T*, void f()->void
 /// (*f)(), float->double, short->int, etc.
 ///
 /// In C, implicit casts always produce rvalues. However, in C++, an
 /// implicit cast whose result is being bound to a reference will be
 /// an lvalue or xvalue. For example:
 ///
 /// @code
 /// class Base { };
 /// class Derived : public Base { };
 /// Derived &&ref();
 /// void f(Derived d) {
 ///   Base& b = d; // initializer is an ImplicitCastExpr
 ///                // to an lvalue of type Base
 ///   Base&& r = ref(); // initializer is an ImplicitCastExpr
 ///                     // to an xvalue of type Base
 /// }
 /// @endcode
 class ImplicitCastExpr final
     : public CastExpr,
       private llvm::TrailingObjects<ImplicitCastExpr, CXXBaseSpecifier *,
                                     FPOptionsOverride> {
 
   ImplicitCastExpr(QualType ty, CastKind kind, Expr *op,
                    unsigned BasePathLength, FPOptionsOverride FPO,
                    ExprValueKind VK)
       : CastExpr(ImplicitCastExprClass, ty, VK, kind, op, BasePathLength,
                  FPO.requiresTrailingStorage()) {
     setDependence(computeDependence(this));
     if (hasStoredFPFeatures())
       *getTrailingFPFeatures() = FPO;
   }
 
   /// Construct an empty implicit cast.
   explicit ImplicitCastExpr(EmptyShell Shell, unsigned PathSize,
                             bool HasFPFeatures)
       : CastExpr(ImplicitCastExprClass, Shell, PathSize, HasFPFeatures) {}
 
   unsigned numTrailingObjects(OverloadToken<CXXBaseSpecifier *>) const {
     return path_size();
   }
 
 public:
   enum OnStack_t { OnStack };
   ImplicitCastExpr(OnStack_t _, QualType ty, CastKind kind, Expr *op,
                    ExprValueKind VK, FPOptionsOverride FPO)
       : CastExpr(ImplicitCastExprClass, ty, VK, kind, op, 0,
                  FPO.requiresTrailingStorage()) {
     if (hasStoredFPFeatures())
       *getTrailingFPFeatures() = FPO;
   }
 
   bool isPartOfExplicitCast() const { return CastExprBits.PartOfExplicitCast; }
   void setIsPartOfExplicitCast(bool PartOfExplicitCast) {
     CastExprBits.PartOfExplicitCast = PartOfExplicitCast;
   }
 
   static ImplicitCastExpr *Create(const ASTContext &Context, QualType T,
                                   CastKind Kind, Expr *Operand,
                                   const CXXCastPath *BasePath,
                                   ExprValueKind Cat, FPOptionsOverride FPO);
 
   static ImplicitCastExpr *CreateEmpty(const ASTContext &Context,
                                        unsigned PathSize, bool HasFPFeatures);
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getSubExpr()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getSubExpr()->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ImplicitCastExprClass;
   }
 
   friend TrailingObjects;
   friend class CastExpr;
 };
 
 /// ExplicitCastExpr - An explicit cast written in the source
 /// code.
 ///
 /// This class is effectively an abstract class, because it provides
 /// the basic representation of an explicitly-written cast without
 /// specifying which kind of cast (C cast, functional cast, static
 /// cast, etc.) was written; specific derived classes represent the
 /// particular style of cast and its location information.
 ///
 /// Unlike implicit casts, explicit cast nodes have two different
 /// types: the type that was written into the source code, and the
 /// actual type of the expression as determined by semantic
 /// analysis. These types may differ slightly. For example, in C++ one
 /// can cast to a reference type, which indicates that the resulting
 /// expression will be an lvalue or xvalue. The reference type, however,
 /// will not be used as the type of the expression.
 class ExplicitCastExpr : public CastExpr {
   /// TInfo - Source type info for the (written) type
   /// this expression is casting to.
   TypeSourceInfo *TInfo;
 
 protected:
   ExplicitCastExpr(StmtClass SC, QualType exprTy, ExprValueKind VK,
                    CastKind kind, Expr *op, unsigned PathSize,
                    bool HasFPFeatures, TypeSourceInfo *writtenTy)
       : CastExpr(SC, exprTy, VK, kind, op, PathSize, HasFPFeatures),
         TInfo(writtenTy) {
     setDependence(computeDependence(this));
   }
 
   /// Construct an empty explicit cast.
   ExplicitCastExpr(StmtClass SC, EmptyShell Shell, unsigned PathSize,
                    bool HasFPFeatures)
       : CastExpr(SC, Shell, PathSize, HasFPFeatures) {}
 
 public:
   /// getTypeInfoAsWritten - Returns the type source info for the type
   /// that this expression is casting to.
   TypeSourceInfo *getTypeInfoAsWritten() const { return TInfo; }
   void setTypeInfoAsWritten(TypeSourceInfo *writtenTy) { TInfo = writtenTy; }
 
   /// getTypeAsWritten - Returns the type that this expression is
   /// casting to, as written in the source code.
   QualType getTypeAsWritten() const { return TInfo->getType(); }
 
   static bool classof(const Stmt *T) {
      return T->getStmtClass() >= firstExplicitCastExprConstant &&
             T->getStmtClass() <= lastExplicitCastExprConstant;
   }
 };
 
 /// CStyleCastExpr - An explicit cast in C (C99 6.5.4) or a C-style
 /// cast in C++ (C++ [expr.cast]), which uses the syntax
 /// (Type)expr. For example: @c (int)f.
 class CStyleCastExpr final
     : public ExplicitCastExpr,
       private llvm::TrailingObjects<CStyleCastExpr, CXXBaseSpecifier *,
                                     FPOptionsOverride> {
   SourceLocation LPLoc; // the location of the left paren
   SourceLocation RPLoc; // the location of the right paren
 
   CStyleCastExpr(QualType exprTy, ExprValueKind vk, CastKind kind, Expr *op,
                  unsigned PathSize, FPOptionsOverride FPO,
                  TypeSourceInfo *writtenTy, SourceLocation l, SourceLocation r)
       : ExplicitCastExpr(CStyleCastExprClass, exprTy, vk, kind, op, PathSize,
                          FPO.requiresTrailingStorage(), writtenTy),
         LPLoc(l), RPLoc(r) {
     if (hasStoredFPFeatures())
       *getTrailingFPFeatures() = FPO;
   }
 
   /// Construct an empty C-style explicit cast.
   explicit CStyleCastExpr(EmptyShell Shell, unsigned PathSize,
                           bool HasFPFeatures)
       : ExplicitCastExpr(CStyleCastExprClass, Shell, PathSize, HasFPFeatures) {}
 
   unsigned numTrailingObjects(OverloadToken<CXXBaseSpecifier *>) const {
     return path_size();
   }
 
 public:
   static CStyleCastExpr *
   Create(const ASTContext &Context, QualType T, ExprValueKind VK, CastKind K,
          Expr *Op, const CXXCastPath *BasePath, FPOptionsOverride FPO,
          TypeSourceInfo *WrittenTy, SourceLocation L, SourceLocation R);
 
   static CStyleCastExpr *CreateEmpty(const ASTContext &Context,
                                      unsigned PathSize, bool HasFPFeatures);
 
   SourceLocation getLParenLoc() const { return LPLoc; }
   void setLParenLoc(SourceLocation L) { LPLoc = L; }
 
   SourceLocation getRParenLoc() const { return RPLoc; }
   void setRParenLoc(SourceLocation L) { RPLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return LPLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getSubExpr()->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == CStyleCastExprClass;
   }
 
   friend TrailingObjects;
   friend class CastExpr;
 };
 
 /// A builtin binary operation expression such as "x + y" or "x <= y".
 ///
 /// This expression node kind describes a builtin binary operation,
 /// such as "x + y" for integer values "x" and "y". The operands will
 /// already have been converted to appropriate types (e.g., by
 /// performing promotions or conversions).
 ///
 /// In C++, where operators may be overloaded, a different kind of
 /// expression node (CXXOperatorCallExpr) is used to express the
 /// invocation of an overloaded operator with operator syntax. Within
 /// a C++ template, whether BinaryOperator or CXXOperatorCallExpr is
 /// used to store an expression "x + y" depends on the subexpressions
 /// for x and y. If neither x or y is type-dependent, and the "+"
 /// operator resolves to a built-in operation, BinaryOperator will be
 /// used to express the computation (x and y may still be
 /// value-dependent). If either x or y is type-dependent, or if the
 /// "+" resolves to an overloaded operator, CXXOperatorCallExpr will
 /// be used to express the computation.
 class BinaryOperator : public Expr {
   enum { LHS, RHS, END_EXPR };
   Stmt *SubExprs[END_EXPR];
 
 public:
   typedef BinaryOperatorKind Opcode;
 
 protected:
   size_t offsetOfTrailingStorage() const;
 
   /// Return a pointer to the trailing FPOptions
   FPOptionsOverride *getTrailingFPFeatures() {
     assert(BinaryOperatorBits.HasFPFeatures);
     return reinterpret_cast<FPOptionsOverride *>(
         reinterpret_cast<char *>(this) + offsetOfTrailingStorage());
   }
   const FPOptionsOverride *getTrailingFPFeatures() const {
     assert(BinaryOperatorBits.HasFPFeatures);
     return reinterpret_cast<const FPOptionsOverride *>(
         reinterpret_cast<const char *>(this) + offsetOfTrailingStorage());
   }
 
   /// Build a binary operator, assuming that appropriate storage has been
   /// allocated for the trailing objects when needed.
   BinaryOperator(const ASTContext &Ctx, Expr *lhs, Expr *rhs, Opcode opc,
                  QualType ResTy, ExprValueKind VK, ExprObjectKind OK,
                  SourceLocation opLoc, FPOptionsOverride FPFeatures);
 
   /// Construct an empty binary operator.
   explicit BinaryOperator(EmptyShell Empty) : Expr(BinaryOperatorClass, Empty) {
     BinaryOperatorBits.Opc = BO_Comma;
     BinaryOperatorBits.ExcludedOverflowPattern = false;
   }
 
 public:
   static BinaryOperator *CreateEmpty(const ASTContext &C, bool hasFPFeatures);
 
   static BinaryOperator *Create(const ASTContext &C, Expr *lhs, Expr *rhs,
                                 Opcode opc, QualType ResTy, ExprValueKind VK,
                                 ExprObjectKind OK, SourceLocation opLoc,
                                 FPOptionsOverride FPFeatures);
   SourceLocation getExprLoc() const { return getOperatorLoc(); }
   SourceLocation getOperatorLoc() const { return BinaryOperatorBits.OpLoc; }
   void setOperatorLoc(SourceLocation L) { BinaryOperatorBits.OpLoc = L; }
 
   Opcode getOpcode() const {
     return static_cast<Opcode>(BinaryOperatorBits.Opc);
   }
   void setOpcode(Opcode Opc) { BinaryOperatorBits.Opc = Opc; }
 
   Expr *getLHS() const { return cast<Expr>(SubExprs[LHS]); }
   void setLHS(Expr *E) { SubExprs[LHS] = E; }
   Expr *getRHS() const { return cast<Expr>(SubExprs[RHS]); }
   void setRHS(Expr *E) { SubExprs[RHS] = E; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getLHS()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getRHS()->getEndLoc();
   }
 
   /// getOpcodeStr - Turn an Opcode enum value into the punctuation char it
   /// corresponds to, e.g. "<<=".
   static StringRef getOpcodeStr(Opcode Op);
 
   StringRef getOpcodeStr() const { return getOpcodeStr(getOpcode()); }
 
   /// Retrieve the binary opcode that corresponds to the given
   /// overloaded operator.
   static Opcode getOverloadedOpcode(OverloadedOperatorKind OO);
 
   /// Retrieve the overloaded operator kind that corresponds to
   /// the given binary opcode.
   static OverloadedOperatorKind getOverloadedOperator(Opcode Opc);
 
   /// predicates to categorize the respective opcodes.
   static bool isPtrMemOp(Opcode Opc) {
     return Opc == BO_PtrMemD || Opc == BO_PtrMemI;
   }
   bool isPtrMemOp() const { return isPtrMemOp(getOpcode()); }
 
   static bool isMultiplicativeOp(Opcode Opc) {
     return Opc >= BO_Mul && Opc <= BO_Rem;
   }
   bool isMultiplicativeOp() const { return isMultiplicativeOp(getOpcode()); }
   static bool isAdditiveOp(Opcode Opc) { return Opc == BO_Add || Opc==BO_Sub; }
   bool isAdditiveOp() const { return isAdditiveOp(getOpcode()); }
   static bool isShiftOp(Opcode Opc) { return Opc == BO_Shl || Opc == BO_Shr; }
   bool isShiftOp() const { return isShiftOp(getOpcode()); }
 
   static bool isBitwiseOp(Opcode Opc) { return Opc >= BO_And && Opc <= BO_Or; }
   bool isBitwiseOp() const { return isBitwiseOp(getOpcode()); }
 
   static bool isRelationalOp(Opcode Opc) { return Opc >= BO_LT && Opc<=BO_GE; }
   bool isRelationalOp() const { return isRelationalOp(getOpcode()); }
 
   static bool isEqualityOp(Opcode Opc) { return Opc == BO_EQ || Opc == BO_NE; }
   bool isEqualityOp() const { return isEqualityOp(getOpcode()); }
 
   static bool isComparisonOp(Opcode Opc) { return Opc >= BO_Cmp && Opc<=BO_NE; }
   bool isComparisonOp() const { return isComparisonOp(getOpcode()); }
 
   static bool isCommaOp(Opcode Opc) { return Opc == BO_Comma; }
   bool isCommaOp() const { return isCommaOp(getOpcode()); }
 
   static Opcode negateComparisonOp(Opcode Opc) {
     switch (Opc) {
     default:
       llvm_unreachable("Not a comparison operator.");
     case BO_LT: return BO_GE;
     case BO_GT: return BO_LE;
     case BO_LE: return BO_GT;
     case BO_GE: return BO_LT;
     case BO_EQ: return BO_NE;
     case BO_NE: return BO_EQ;
     }
   }
 
   static Opcode reverseComparisonOp(Opcode Opc) {
     switch (Opc) {
     default:
       llvm_unreachable("Not a comparison operator.");
     case BO_LT: return BO_GT;
     case BO_GT: return BO_LT;
     case BO_LE: return BO_GE;
     case BO_GE: return BO_LE;
     case BO_EQ:
     case BO_NE:
       return Opc;
     }
   }
 
   static bool isLogicalOp(Opcode Opc) { return Opc == BO_LAnd || Opc==BO_LOr; }
   bool isLogicalOp() const { return isLogicalOp(getOpcode()); }
 
   static bool isAssignmentOp(Opcode Opc) {
     return Opc >= BO_Assign && Opc <= BO_OrAssign;
   }
   bool isAssignmentOp() const { return isAssignmentOp(getOpcode()); }
 
   static bool isCompoundAssignmentOp(Opcode Opc) {
     return Opc > BO_Assign && Opc <= BO_OrAssign;
   }
   bool isCompoundAssignmentOp() const {
     return isCompoundAssignmentOp(getOpcode());
   }
   static Opcode getOpForCompoundAssignment(Opcode Opc) {
     assert(isCompoundAssignmentOp(Opc));
     if (Opc >= BO_AndAssign)
       return Opcode(unsigned(Opc) - BO_AndAssign + BO_And);
     else
       return Opcode(unsigned(Opc) - BO_MulAssign + BO_Mul);
   }
 
   static bool isShiftAssignOp(Opcode Opc) {
     return Opc == BO_ShlAssign || Opc == BO_ShrAssign;
   }
   bool isShiftAssignOp() const {
     return isShiftAssignOp(getOpcode());
   }
 
   /// Return true if a binary operator using the specified opcode and operands
   /// would match the 'p = (i8*)nullptr + n' idiom for casting a pointer-sized
   /// integer to a pointer.
   static bool isNullPointerArithmeticExtension(ASTContext &Ctx, Opcode Opc,
                                                const Expr *LHS,
                                                const Expr *RHS);
 
   static bool classof(const Stmt *S) {
     return S->getStmtClass() >= firstBinaryOperatorConstant &&
            S->getStmtClass() <= lastBinaryOperatorConstant;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0]+END_EXPR);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
 
   /// Set and fetch the bit that shows whether FPFeatures needs to be
   /// allocated in Trailing Storage
   void setHasStoredFPFeatures(bool B) { BinaryOperatorBits.HasFPFeatures = B; }
   bool hasStoredFPFeatures() const { return BinaryOperatorBits.HasFPFeatures; }
 
   /// Set and get the bit that informs arithmetic overflow sanitizers whether
   /// or not they should exclude certain BinaryOperators from instrumentation
   void setExcludedOverflowPattern(bool B) {
     BinaryOperatorBits.ExcludedOverflowPattern = B;
   }
   bool hasExcludedOverflowPattern() const {
     return BinaryOperatorBits.ExcludedOverflowPattern;
   }
 
   /// Get FPFeatures from trailing storage
   FPOptionsOverride getStoredFPFeatures() const {
     assert(hasStoredFPFeatures());
     return *getTrailingFPFeatures();
   }
   /// Set FPFeatures in trailing storage, used only by Serialization
   void setStoredFPFeatures(FPOptionsOverride F) {
     assert(BinaryOperatorBits.HasFPFeatures);
     *getTrailingFPFeatures() = F;
   }
   /// Get the store FPOptionsOverride or default if not stored.
   FPOptionsOverride getStoredFPFeaturesOrDefault() const {
     return hasStoredFPFeatures() ? getStoredFPFeatures() : FPOptionsOverride();
   }
 
   /// Get the FP features status of this operator. Only meaningful for
   /// operations on floating point types.
   FPOptions getFPFeaturesInEffect(const LangOptions &LO) const {
     if (BinaryOperatorBits.HasFPFeatures)
       return getStoredFPFeatures().applyOverrides(LO);
     return FPOptions::defaultWithoutTrailingStorage(LO);
   }
 
   // This is used in ASTImporter
   FPOptionsOverride getFPFeatures() const {
     if (BinaryOperatorBits.HasFPFeatures)
       return getStoredFPFeatures();
     return FPOptionsOverride();
   }
 
   /// Get the FP contractibility status of this operator. Only meaningful for
   /// operations on floating point types.
   bool isFPContractableWithinStatement(const LangOptions &LO) const {
     return getFPFeaturesInEffect(LO).allowFPContractWithinStatement();
   }
 
   /// Get the FENV_ACCESS status of this operator. Only meaningful for
   /// operations on floating point types.
   bool isFEnvAccessOn(const LangOptions &LO) const {
     return getFPFeaturesInEffect(LO).getAllowFEnvAccess();
   }
 
 protected:
   BinaryOperator(const ASTContext &Ctx, Expr *lhs, Expr *rhs, Opcode opc,
                  QualType ResTy, ExprValueKind VK, ExprObjectKind OK,
                  SourceLocation opLoc, FPOptionsOverride FPFeatures,
                  bool dead2);
 
   /// Construct an empty BinaryOperator, SC is CompoundAssignOperator.
   BinaryOperator(StmtClass SC, EmptyShell Empty) : Expr(SC, Empty) {
     BinaryOperatorBits.Opc = BO_MulAssign;
   }
 
   /// Return the size in bytes needed for the trailing objects.
   /// Used to allocate the right amount of storage.
   static unsigned sizeOfTrailingObjects(bool HasFPFeatures) {
     return HasFPFeatures * sizeof(FPOptionsOverride);
   }
 };
 
 /// CompoundAssignOperator - For compound assignments (e.g. +=), we keep
 /// track of the type the operation is performed in.  Due to the semantics of
 /// these operators, the operands are promoted, the arithmetic performed, an
 /// implicit conversion back to the result type done, then the assignment takes
 /// place.  This captures the intermediate type which the computation is done
 /// in.
 class CompoundAssignOperator : public BinaryOperator {
   QualType ComputationLHSType;
   QualType ComputationResultType;
 
   /// Construct an empty CompoundAssignOperator.
   explicit CompoundAssignOperator(const ASTContext &C, EmptyShell Empty,
                                   bool hasFPFeatures)
       : BinaryOperator(CompoundAssignOperatorClass, Empty) {}
 
 protected:
   CompoundAssignOperator(const ASTContext &C, Expr *lhs, Expr *rhs, Opcode opc,
                          QualType ResType, ExprValueKind VK, ExprObjectKind OK,
                          SourceLocation OpLoc, FPOptionsOverride FPFeatures,
                          QualType CompLHSType, QualType CompResultType)
       : BinaryOperator(C, lhs, rhs, opc, ResType, VK, OK, OpLoc, FPFeatures,
                        true),
         ComputationLHSType(CompLHSType), ComputationResultType(CompResultType) {
     assert(isCompoundAssignmentOp() &&
            "Only should be used for compound assignments");
   }
 
 public:
   static CompoundAssignOperator *CreateEmpty(const ASTContext &C,
                                              bool hasFPFeatures);
 
   static CompoundAssignOperator *
   Create(const ASTContext &C, Expr *lhs, Expr *rhs, Opcode opc, QualType ResTy,
          ExprValueKind VK, ExprObjectKind OK, SourceLocation opLoc,
          FPOptionsOverride FPFeatures, QualType CompLHSType = QualType(),
          QualType CompResultType = QualType());
 
   // The two computation types are the type the LHS is converted
   // to for the computation and the type of the result; the two are
   // distinct in a few cases (specifically, int+=ptr and ptr-=ptr).
   QualType getComputationLHSType() const { return ComputationLHSType; }
   void setComputationLHSType(QualType T) { ComputationLHSType = T; }
 
   QualType getComputationResultType() const { return ComputationResultType; }
   void setComputationResultType(QualType T) { ComputationResultType = T; }
 
   static bool classof(const Stmt *S) {
     return S->getStmtClass() == CompoundAssignOperatorClass;
   }
 };
 
 inline size_t BinaryOperator::offsetOfTrailingStorage() const {
   assert(BinaryOperatorBits.HasFPFeatures);
   return isa<CompoundAssignOperator>(this) ? sizeof(CompoundAssignOperator)
                                            : sizeof(BinaryOperator);
 }
 
 /// AbstractConditionalOperator - An abstract base class for
 /// ConditionalOperator and BinaryConditionalOperator.
 class AbstractConditionalOperator : public Expr {
   SourceLocation QuestionLoc, ColonLoc;
   friend class ASTStmtReader;
 
 protected:
   AbstractConditionalOperator(StmtClass SC, QualType T, ExprValueKind VK,
                               ExprObjectKind OK, SourceLocation qloc,
                               SourceLocation cloc)
       : Expr(SC, T, VK, OK), QuestionLoc(qloc), ColonLoc(cloc) {}
 
   AbstractConditionalOperator(StmtClass SC, EmptyShell Empty)
     : Expr(SC, Empty) { }
 
 public:
   /// getCond - Return the expression representing the condition for
   ///   the ?: operator.
   Expr *getCond() const;
 
   /// getTrueExpr - Return the subexpression representing the value of
   ///   the expression if the condition evaluates to true.
   Expr *getTrueExpr() const;
 
   /// getFalseExpr - Return the subexpression representing the value of
   ///   the expression if the condition evaluates to false.  This is
   ///   the same as getRHS.
   Expr *getFalseExpr() const;
 
   SourceLocation getQuestionLoc() const { return QuestionLoc; }
   SourceLocation getColonLoc() const { return ColonLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ConditionalOperatorClass ||
            T->getStmtClass() == BinaryConditionalOperatorClass;
   }
 };
 
 /// ConditionalOperator - The ?: ternary operator.  The GNU "missing
 /// middle" extension is a BinaryConditionalOperator.
 class ConditionalOperator : public AbstractConditionalOperator {
   enum { COND, LHS, RHS, END_EXPR };
   Stmt* SubExprs[END_EXPR]; // Left/Middle/Right hand sides.
 
   friend class ASTStmtReader;
 public:
   ConditionalOperator(Expr *cond, SourceLocation QLoc, Expr *lhs,
                       SourceLocation CLoc, Expr *rhs, QualType t,
                       ExprValueKind VK, ExprObjectKind OK)
       : AbstractConditionalOperator(ConditionalOperatorClass, t, VK, OK, QLoc,
                                     CLoc) {
     SubExprs[COND] = cond;
     SubExprs[LHS] = lhs;
     SubExprs[RHS] = rhs;
     setDependence(computeDependence(this));
   }
 
   /// Build an empty conditional operator.
   explicit ConditionalOperator(EmptyShell Empty)
     : AbstractConditionalOperator(ConditionalOperatorClass, Empty) { }
 
   /// getCond - Return the expression representing the condition for
   ///   the ?: operator.
   Expr *getCond() const { return cast<Expr>(SubExprs[COND]); }
 
   /// getTrueExpr - Return the subexpression representing the value of
   ///   the expression if the condition evaluates to true.
   Expr *getTrueExpr() const { return cast<Expr>(SubExprs[LHS]); }
 
   /// getFalseExpr - Return the subexpression representing the value of
   ///   the expression if the condition evaluates to false.  This is
   ///   the same as getRHS.
   Expr *getFalseExpr() const { return cast<Expr>(SubExprs[RHS]); }
 
   Expr *getLHS() const { return cast<Expr>(SubExprs[LHS]); }
   Expr *getRHS() const { return cast<Expr>(SubExprs[RHS]); }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getCond()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getRHS()->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ConditionalOperatorClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0]+END_EXPR);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
 };
 
 /// BinaryConditionalOperator - The GNU extension to the conditional
 /// operator which allows the middle operand to be omitted.
 ///
 /// This is a different expression kind on the assumption that almost
 /// every client ends up needing to know that these are different.
 class BinaryConditionalOperator : public AbstractConditionalOperator {
   enum { COMMON, COND, LHS, RHS, NUM_SUBEXPRS };
 
   /// - the common condition/left-hand-side expression, which will be
   ///   evaluated as the opaque value
   /// - the condition, expressed in terms of the opaque value
   /// - the left-hand-side, expressed in terms of the opaque value
   /// - the right-hand-side
   Stmt *SubExprs[NUM_SUBEXPRS];
   OpaqueValueExpr *OpaqueValue;
 
   friend class ASTStmtReader;
 public:
   BinaryConditionalOperator(Expr *common, OpaqueValueExpr *opaqueValue,
                             Expr *cond, Expr *lhs, Expr *rhs,
                             SourceLocation qloc, SourceLocation cloc,
                             QualType t, ExprValueKind VK, ExprObjectKind OK)
       : AbstractConditionalOperator(BinaryConditionalOperatorClass, t, VK, OK,
                                     qloc, cloc),
         OpaqueValue(opaqueValue) {
     SubExprs[COMMON] = common;
     SubExprs[COND] = cond;
     SubExprs[LHS] = lhs;
     SubExprs[RHS] = rhs;
     assert(OpaqueValue->getSourceExpr() == common && "Wrong opaque value");
     setDependence(computeDependence(this));
   }
 
   /// Build an empty conditional operator.
   explicit BinaryConditionalOperator(EmptyShell Empty)
     : AbstractConditionalOperator(BinaryConditionalOperatorClass, Empty) { }
 
   /// getCommon - Return the common expression, written to the
   ///   left of the condition.  The opaque value will be bound to the
   ///   result of this expression.
   Expr *getCommon() const { return cast<Expr>(SubExprs[COMMON]); }
 
   /// getOpaqueValue - Return the opaque value placeholder.
   OpaqueValueExpr *getOpaqueValue() const { return OpaqueValue; }
 
   /// getCond - Return the condition expression; this is defined
   ///   in terms of the opaque value.
   Expr *getCond() const { return cast<Expr>(SubExprs[COND]); }
 
   /// getTrueExpr - Return the subexpression which will be
   ///   evaluated if the condition evaluates to true;  this is defined
   ///   in terms of the opaque value.
   Expr *getTrueExpr() const {
     return cast<Expr>(SubExprs[LHS]);
   }
 
   /// getFalseExpr - Return the subexpression which will be
   ///   evaluated if the condition evaluates to false; this is
   ///   defined in terms of the opaque value.
   Expr *getFalseExpr() const {
     return cast<Expr>(SubExprs[RHS]);
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getCommon()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getFalseExpr()->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == BinaryConditionalOperatorClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(SubExprs, SubExprs + NUM_SUBEXPRS);
   }
   const_child_range children() const {
     return const_child_range(SubExprs, SubExprs + NUM_SUBEXPRS);
   }
 };
 
 inline Expr *AbstractConditionalOperator::getCond() const {
   if (const ConditionalOperator *co = dyn_cast<ConditionalOperator>(this))
     return co->getCond();
   return cast<BinaryConditionalOperator>(this)->getCond();
 }
 
 inline Expr *AbstractConditionalOperator::getTrueExpr() const {
   if (const ConditionalOperator *co = dyn_cast<ConditionalOperator>(this))
     return co->getTrueExpr();
   return cast<BinaryConditionalOperator>(this)->getTrueExpr();
 }
 
 inline Expr *AbstractConditionalOperator::getFalseExpr() const {
   if (const ConditionalOperator *co = dyn_cast<ConditionalOperator>(this))
     return co->getFalseExpr();
   return cast<BinaryConditionalOperator>(this)->getFalseExpr();
 }
 
 /// AddrLabelExpr - The GNU address of label extension, representing &&label.
 class AddrLabelExpr : public Expr {
   SourceLocation AmpAmpLoc, LabelLoc;
   LabelDecl *Label;
 public:
   AddrLabelExpr(SourceLocation AALoc, SourceLocation LLoc, LabelDecl *L,
                 QualType t)
       : Expr(AddrLabelExprClass, t, VK_PRValue, OK_Ordinary), AmpAmpLoc(AALoc),
         LabelLoc(LLoc), Label(L) {
     setDependence(ExprDependence::None);
   }
 
   /// Build an empty address of a label expression.
   explicit AddrLabelExpr(EmptyShell Empty)
     : Expr(AddrLabelExprClass, Empty) { }
 
   SourceLocation getAmpAmpLoc() const { return AmpAmpLoc; }
   void setAmpAmpLoc(SourceLocation L) { AmpAmpLoc = L; }
   SourceLocation getLabelLoc() const { return LabelLoc; }
   void setLabelLoc(SourceLocation L) { LabelLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return AmpAmpLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return LabelLoc; }
 
   LabelDecl *getLabel() const { return Label; }
   void setLabel(LabelDecl *L) { Label = L; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == AddrLabelExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 /// StmtExpr - This is the GNU Statement Expression extension: ({int X=4; X;}).
 /// The StmtExpr contains a single CompoundStmt node, which it evaluates and
 /// takes the value of the last subexpression.
 ///
 /// A StmtExpr is always an r-value; values "returned" out of a
 /// StmtExpr will be copied.
 class StmtExpr : public Expr {
   Stmt *SubStmt;
   SourceLocation LParenLoc, RParenLoc;
 public:
   StmtExpr(CompoundStmt *SubStmt, QualType T, SourceLocation LParenLoc,
            SourceLocation RParenLoc, unsigned TemplateDepth)
       : Expr(StmtExprClass, T, VK_PRValue, OK_Ordinary), SubStmt(SubStmt),
         LParenLoc(LParenLoc), RParenLoc(RParenLoc) {
     setDependence(computeDependence(this, TemplateDepth));
     // FIXME: A templated statement expression should have an associated
     // DeclContext so that nested declarations always have a dependent context.
     StmtExprBits.TemplateDepth = TemplateDepth;
   }
 
   /// Build an empty statement expression.
   explicit StmtExpr(EmptyShell Empty) : Expr(StmtExprClass, Empty) { }
 
   CompoundStmt *getSubStmt() { return cast<CompoundStmt>(SubStmt); }
   const CompoundStmt *getSubStmt() const { return cast<CompoundStmt>(SubStmt); }
   void setSubStmt(CompoundStmt *S) { SubStmt = S; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return LParenLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   SourceLocation getLParenLoc() const { return LParenLoc; }
   void setLParenLoc(SourceLocation L) { LParenLoc = L; }
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   unsigned getTemplateDepth() const { return StmtExprBits.TemplateDepth; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == StmtExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&SubStmt, &SubStmt+1); }
   const_child_range children() const {
     return const_child_range(&SubStmt, &SubStmt + 1);
   }
 };
 
 /// ShuffleVectorExpr - clang-specific builtin-in function
 /// __builtin_shufflevector.
 /// This AST node represents a operator that does a constant
 /// shuffle, similar to LLVM's shufflevector instruction. It takes
 /// two vectors and a variable number of constant indices,
 /// and returns the appropriately shuffled vector.
 class ShuffleVectorExpr : public Expr {
   SourceLocation BuiltinLoc, RParenLoc;
 
   // SubExprs - the list of values passed to the __builtin_shufflevector
   // function. The first two are vectors, and the rest are constant
   // indices.  The number of values in this list is always
   // 2+the number of indices in the vector type.
   Stmt **SubExprs;
   unsigned NumExprs;
 
 public:
   ShuffleVectorExpr(const ASTContext &C, ArrayRef<Expr*> args, QualType Type,
                     SourceLocation BLoc, SourceLocation RP);
 
   /// Build an empty vector-shuffle expression.
   explicit ShuffleVectorExpr(EmptyShell Empty)
     : Expr(ShuffleVectorExprClass, Empty), SubExprs(nullptr) { }
 
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
   void setBuiltinLoc(SourceLocation L) { BuiltinLoc = L; }
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ShuffleVectorExprClass;
   }
 
   /// getNumSubExprs - Return the size of the SubExprs array.  This includes the
   /// constant expression, the actual arguments passed in, and the function
   /// pointers.
   unsigned getNumSubExprs() const { return NumExprs; }
 
   /// Retrieve the array of expressions.
   Expr **getSubExprs() { return reinterpret_cast<Expr **>(SubExprs); }
 
   /// getExpr - Return the Expr at the specified index.
   Expr *getExpr(unsigned Index) {
     assert((Index < NumExprs) && "Arg access out of range!");
     return cast<Expr>(SubExprs[Index]);
   }
   const Expr *getExpr(unsigned Index) const {
     assert((Index < NumExprs) && "Arg access out of range!");
     return cast<Expr>(SubExprs[Index]);
   }
 
   void setExprs(const ASTContext &C, ArrayRef<Expr *> Exprs);
 
   llvm::APSInt getShuffleMaskIdx(const ASTContext &Ctx, unsigned N) const {
     assert((N < NumExprs - 2) && "Shuffle idx out of range!");
     return getExpr(N+2)->EvaluateKnownConstInt(Ctx);
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0]+NumExprs);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + NumExprs);
   }
 };
 
 /// ConvertVectorExpr - Clang builtin function __builtin_convertvector
 /// This AST node provides support for converting a vector type to another
 /// vector type of the same arity.
 class ConvertVectorExpr : public Expr {
 private:
   Stmt *SrcExpr;
   TypeSourceInfo *TInfo;
   SourceLocation BuiltinLoc, RParenLoc;
 
   friend class ASTReader;
   friend class ASTStmtReader;
   explicit ConvertVectorExpr(EmptyShell Empty) : Expr(ConvertVectorExprClass, Empty) {}
 
 public:
   ConvertVectorExpr(Expr *SrcExpr, TypeSourceInfo *TI, QualType DstType,
                     ExprValueKind VK, ExprObjectKind OK,
                     SourceLocation BuiltinLoc, SourceLocation RParenLoc)
       : Expr(ConvertVectorExprClass, DstType, VK, OK), SrcExpr(SrcExpr),
         TInfo(TI), BuiltinLoc(BuiltinLoc), RParenLoc(RParenLoc) {
     setDependence(computeDependence(this));
   }
 
   /// getSrcExpr - Return the Expr to be converted.
   Expr *getSrcExpr() const { return cast<Expr>(SrcExpr); }
 
   /// getTypeSourceInfo - Return the destination type.
   TypeSourceInfo *getTypeSourceInfo() const {
     return TInfo;
   }
   void setTypeSourceInfo(TypeSourceInfo *ti) {
     TInfo = ti;
   }
 
   /// getBuiltinLoc - Return the location of the __builtin_convertvector token.
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
 
   /// getRParenLoc - Return the location of final right parenthesis.
   SourceLocation getRParenLoc() const { return RParenLoc; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ConvertVectorExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&SrcExpr, &SrcExpr+1); }
   const_child_range children() const {
     return const_child_range(&SrcExpr, &SrcExpr + 1);
   }
 };
 
 /// ChooseExpr - GNU builtin-in function __builtin_choose_expr.
 /// This AST node is similar to the conditional operator (?:) in C, with
 /// the following exceptions:
 /// - the test expression must be a integer constant expression.
 /// - the expression returned acts like the chosen subexpression in every
 ///   visible way: the type is the same as that of the chosen subexpression,
 ///   and all predicates (whether it's an l-value, whether it's an integer
 ///   constant expression, etc.) return the same result as for the chosen
 ///   sub-expression.
 class ChooseExpr : public Expr {
   enum { COND, LHS, RHS, END_EXPR };
   Stmt* SubExprs[END_EXPR]; // Left/Middle/Right hand sides.
   SourceLocation BuiltinLoc, RParenLoc;
   bool CondIsTrue;
 public:
   ChooseExpr(SourceLocation BLoc, Expr *cond, Expr *lhs, Expr *rhs, QualType t,
              ExprValueKind VK, ExprObjectKind OK, SourceLocation RP,
              bool condIsTrue)
       : Expr(ChooseExprClass, t, VK, OK), BuiltinLoc(BLoc), RParenLoc(RP),
         CondIsTrue(condIsTrue) {
     SubExprs[COND] = cond;
     SubExprs[LHS] = lhs;
     SubExprs[RHS] = rhs;
 
     setDependence(computeDependence(this));
   }
 
   /// Build an empty __builtin_choose_expr.
   explicit ChooseExpr(EmptyShell Empty) : Expr(ChooseExprClass, Empty) { }
 
   /// isConditionTrue - Return whether the condition is true (i.e. not
   /// equal to zero).
   bool isConditionTrue() const {
     assert(!isConditionDependent() &&
            "Dependent condition isn't true or false");
     return CondIsTrue;
   }
   void setIsConditionTrue(bool isTrue) { CondIsTrue = isTrue; }
 
   bool isConditionDependent() const {
     return getCond()->isTypeDependent() || getCond()->isValueDependent();
   }
 
   /// getChosenSubExpr - Return the subexpression chosen according to the
   /// condition.
   Expr *getChosenSubExpr() const {
     return isConditionTrue() ? getLHS() : getRHS();
   }
 
   Expr *getCond() const { return cast<Expr>(SubExprs[COND]); }
   void setCond(Expr *E) { SubExprs[COND] = E; }
   Expr *getLHS() const { return cast<Expr>(SubExprs[LHS]); }
   void setLHS(Expr *E) { SubExprs[LHS] = E; }
   Expr *getRHS() const { return cast<Expr>(SubExprs[RHS]); }
   void setRHS(Expr *E) { SubExprs[RHS] = E; }
 
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
   void setBuiltinLoc(SourceLocation L) { BuiltinLoc = L; }
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ChooseExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[0], &SubExprs[0]+END_EXPR);
   }
   const_child_range children() const {
     return const_child_range(&SubExprs[0], &SubExprs[0] + END_EXPR);
   }
 };
 
 /// GNUNullExpr - Implements the GNU __null extension, which is a name
 /// for a null pointer constant that has integral type (e.g., int or
 /// long) and is the same size and alignment as a pointer. The __null
 /// extension is typically only used by system headers, which define
 /// NULL as __null in C++ rather than using 0 (which is an integer
 /// that may not match the size of a pointer).
 class GNUNullExpr : public Expr {
   /// TokenLoc - The location of the __null keyword.
   SourceLocation TokenLoc;
 
 public:
   GNUNullExpr(QualType Ty, SourceLocation Loc)
       : Expr(GNUNullExprClass, Ty, VK_PRValue, OK_Ordinary), TokenLoc(Loc) {
     setDependence(ExprDependence::None);
   }
 
   /// Build an empty GNU __null expression.
   explicit GNUNullExpr(EmptyShell Empty) : Expr(GNUNullExprClass, Empty) { }
 
   /// getTokenLocation - The location of the __null token.
   SourceLocation getTokenLocation() const { return TokenLoc; }
   void setTokenLocation(SourceLocation L) { TokenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return TokenLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return TokenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == GNUNullExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 /// Represents a call to the builtin function \c __builtin_va_arg.
 class VAArgExpr : public Expr {
   Stmt *Val;
   llvm::PointerIntPair<TypeSourceInfo *, 1, bool> TInfo;
   SourceLocation BuiltinLoc, RParenLoc;
 public:
   VAArgExpr(SourceLocation BLoc, Expr *e, TypeSourceInfo *TInfo,
             SourceLocation RPLoc, QualType t, bool IsMS)
       : Expr(VAArgExprClass, t, VK_PRValue, OK_Ordinary), Val(e),
         TInfo(TInfo, IsMS), BuiltinLoc(BLoc), RParenLoc(RPLoc) {
     setDependence(computeDependence(this));
   }
 
   /// Create an empty __builtin_va_arg expression.
   explicit VAArgExpr(EmptyShell Empty)
       : Expr(VAArgExprClass, Empty), Val(nullptr), TInfo(nullptr, false) {}
 
   const Expr *getSubExpr() const { return cast<Expr>(Val); }
   Expr *getSubExpr() { return cast<Expr>(Val); }
   void setSubExpr(Expr *E) { Val = E; }
 
   /// Returns whether this is really a Win64 ABI va_arg expression.
   bool isMicrosoftABI() const { return TInfo.getInt(); }
   void setIsMicrosoftABI(bool IsMS) { TInfo.setInt(IsMS); }
 
   TypeSourceInfo *getWrittenTypeInfo() const { return TInfo.getPointer(); }
   void setWrittenTypeInfo(TypeSourceInfo *TI) { TInfo.setPointer(TI); }
 
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
   void setBuiltinLoc(SourceLocation L) { BuiltinLoc = L; }
 
   SourceLocation getRParenLoc() const { return RParenLoc; }
   void setRParenLoc(SourceLocation L) { RParenLoc = L; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == VAArgExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Val, &Val+1); }
   const_child_range children() const {
     return const_child_range(&Val, &Val + 1);
   }
 };
 
 enum class SourceLocIdentKind {
   Function,
   FuncSig,
   File,
   FileName,
   Line,
   Column,
   SourceLocStruct
 };
 
 /// Represents a function call to one of __builtin_LINE(), __builtin_COLUMN(),
 /// __builtin_FUNCTION(), __builtin_FUNCSIG(), __builtin_FILE(),
 /// __builtin_FILE_NAME() or __builtin_source_location().
 class SourceLocExpr final : public Expr {
   SourceLocation BuiltinLoc, RParenLoc;
   DeclContext *ParentContext;
 
 public:
   SourceLocExpr(const ASTContext &Ctx, SourceLocIdentKind Type,
                 QualType ResultTy, SourceLocation BLoc,
                 SourceLocation RParenLoc, DeclContext *Context);
 
   /// Build an empty call expression.
   explicit SourceLocExpr(EmptyShell Empty) : Expr(SourceLocExprClass, Empty) {}
 
   /// Return the result of evaluating this SourceLocExpr in the specified
   /// (and possibly null) default argument or initialization context.
   APValue EvaluateInContext(const ASTContext &Ctx,
                             const Expr *DefaultExpr) const;
 
   /// Return a string representing the name of the specific builtin function.
   StringRef getBuiltinStr() const;
 
   SourceLocIdentKind getIdentKind() const {
     return static_cast<SourceLocIdentKind>(SourceLocExprBits.Kind);
   }
 
   bool isIntType() const {
     switch (getIdentKind()) {
     case SourceLocIdentKind::File:
     case SourceLocIdentKind::FileName:
     case SourceLocIdentKind::Function:
     case SourceLocIdentKind::FuncSig:
     case SourceLocIdentKind::SourceLocStruct:
       return false;
     case SourceLocIdentKind::Line:
     case SourceLocIdentKind::Column:
       return true;
     }
     llvm_unreachable("unknown source location expression kind");
   }
 
   /// If the SourceLocExpr has been resolved return the subexpression
   /// representing the resolved value. Otherwise return null.
   const DeclContext *getParentContext() const { return ParentContext; }
   DeclContext *getParentContext() { return ParentContext; }
 
   SourceLocation getLocation() const { return BuiltinLoc; }
   SourceLocation getBeginLoc() const { return BuiltinLoc; }
   SourceLocation getEndLoc() const { return RParenLoc; }
 
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(child_iterator(), child_iterator());
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == SourceLocExprClass;
   }
 
   static bool MayBeDependent(SourceLocIdentKind Kind) {
     switch (Kind) {
     case SourceLocIdentKind::Function:
     case SourceLocIdentKind::FuncSig:
     case SourceLocIdentKind::SourceLocStruct:
       return true;
     default:
       return false;
     }
   }
 
 private:
   friend class ASTStmtReader;
 };
 
 /// Stores data related to a single #embed directive.
 struct EmbedDataStorage {
   StringLiteral *BinaryData;
   size_t getDataElementCount() const { return BinaryData->getByteLength(); }
 };
 
 /// Represents a reference to #emded data. By default, this references the whole
 /// range. Otherwise it represents a subrange of data imported by #embed
 /// directive. Needed to handle nested initializer lists with #embed directives.
 /// Example:
 ///  struct S {
 ///    int x, y;
 ///  };
 ///
 ///  struct T {
 ///    int x[2];
 ///    struct S s
 ///  };
 ///
 ///  struct T t[] = {
 ///  #embed "data" // data contains 10 elements;
 ///  };
 ///
 /// The resulting semantic form of initializer list will contain (EE stands
 /// for EmbedExpr):
 ///  { {EE(first two data elements), {EE(3rd element), EE(4th element) }},
 ///  { {EE(5th and 6th element), {EE(7th element), EE(8th element) }},
 ///  { {EE(9th and 10th element), { zeroinitializer }}}
 ///
 /// EmbedExpr inside of a semantic initializer list and referencing more than
 /// one element can only appear for arrays of scalars.
 class EmbedExpr final : public Expr {
   SourceLocation EmbedKeywordLoc;
   IntegerLiteral *FakeChildNode = nullptr;
   const ASTContext *Ctx = nullptr;
   EmbedDataStorage *Data;
   unsigned Begin = 0;
   unsigned NumOfElements;
 
 public:
   EmbedExpr(const ASTContext &Ctx, SourceLocation Loc, EmbedDataStorage *Data,
             unsigned Begin, unsigned NumOfElements);
   explicit EmbedExpr(EmptyShell Empty) : Expr(SourceLocExprClass, Empty) {}
 
   SourceLocation getLocation() const { return EmbedKeywordLoc; }
   SourceLocation getBeginLoc() const { return EmbedKeywordLoc; }
   SourceLocation getEndLoc() const { return EmbedKeywordLoc; }
 
   StringLiteral *getDataStringLiteral() const { return Data->BinaryData; }
   EmbedDataStorage *getData() const { return Data; }
 
   unsigned getStartingElementPos() const { return Begin; }
   size_t getDataElementCount() const { return NumOfElements; }
 
   // Allows accessing every byte of EmbedExpr data and iterating over it.
   // An Iterator knows the EmbedExpr that it refers to, and an offset value
   // within the data.
   // Dereferencing an Iterator results in construction of IntegerLiteral AST
   // node filled with byte of data of the corresponding EmbedExpr within offset
   // that the Iterator currently has.
   template <bool Const>
   class ChildElementIter
       : public llvm::iterator_facade_base<
             ChildElementIter<Const>, std::random_access_iterator_tag,
             std::conditional_t<Const, const IntegerLiteral *,
                                IntegerLiteral *>> {
     friend class EmbedExpr;
 
     EmbedExpr *EExpr = nullptr;
     unsigned long long CurOffset = ULLONG_MAX;
     using BaseTy = typename ChildElementIter::iterator_facade_base;
 
     ChildElementIter(EmbedExpr *E) : EExpr(E) {
       if (E)
         CurOffset = E->getStartingElementPos();
     }
 
   public:
     ChildElementIter() : CurOffset(ULLONG_MAX) {}
     typename BaseTy::reference operator*() const {
       assert(EExpr && CurOffset != ULLONG_MAX &&
              "trying to dereference an invalid iterator");
       IntegerLiteral *N = EExpr->FakeChildNode;
       N->setValue(*EExpr->Ctx,
                   llvm::APInt(N->getValue().getBitWidth(),
                               EExpr->Data->BinaryData->getCodeUnit(CurOffset),
                               N->getType()->isSignedIntegerType()));
       // We want to return a reference to the fake child node in the
       // EmbedExpr, not the local variable N.
       return const_cast<typename BaseTy::reference>(EExpr->FakeChildNode);
     }
     typename BaseTy::pointer operator->() const { return **this; }
     using BaseTy::operator++;
     ChildElementIter &operator++() {
       assert(EExpr && "trying to increment an invalid iterator");
       assert(CurOffset != ULLONG_MAX &&
              "Already at the end of what we can iterate over");
       if (++CurOffset >=
           EExpr->getDataElementCount() + EExpr->getStartingElementPos()) {
         CurOffset = ULLONG_MAX;
         EExpr = nullptr;
       }
       return *this;
     }
     bool operator==(ChildElementIter Other) const {
       return (EExpr == Other.EExpr && CurOffset == Other.CurOffset);
     }
   }; // class ChildElementIter
 
 public:
   using fake_child_range = llvm::iterator_range<ChildElementIter<false>>;
   using const_fake_child_range = llvm::iterator_range<ChildElementIter<true>>;
 
   fake_child_range underlying_data_elements() {
     return fake_child_range(ChildElementIter<false>(this),
                             ChildElementIter<false>());
   }
 
   const_fake_child_range underlying_data_elements() const {
     return const_fake_child_range(
         ChildElementIter<true>(const_cast<EmbedExpr *>(this)),
         ChildElementIter<true>());
   }
 
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
 
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == EmbedExprClass;
   }
 
   ChildElementIter<false> begin() { return ChildElementIter<false>(this); }
 
   ChildElementIter<true> begin() const {
     return ChildElementIter<true>(const_cast<EmbedExpr *>(this));
   }
 
   template <typename Call, typename... Targs>
   bool doForEachDataElement(Call &&C, unsigned &StartingIndexInArray,
                             Targs &&...Fargs) const {
     for (auto It : underlying_data_elements()) {
       if (!std::invoke(std::forward<Call>(C), const_cast<IntegerLiteral *>(It),
                        StartingIndexInArray, std::forward<Targs>(Fargs)...))
         return false;
       StartingIndexInArray++;
     }
     return true;
   }
 
 private:
   friend class ASTStmtReader;
 };
 
 /// Describes an C or C++ initializer list.
 ///
 /// InitListExpr describes an initializer list, which can be used to
 /// initialize objects of different types, including
 /// struct/class/union types, arrays, and vectors. For example:
 ///
 /// @code
 /// struct foo x = { 1, { 2, 3 } };
 /// @endcode
 ///
 /// Prior to semantic analysis, an initializer list will represent the
 /// initializer list as written by the user, but will have the
 /// placeholder type "void". This initializer list is called the
 /// syntactic form of the initializer, and may contain C99 designated
 /// initializers (represented as DesignatedInitExprs), initializations
 /// of subobject members without explicit braces, and so on. Clients
 /// interested in the original syntax of the initializer list should
 /// use the syntactic form of the initializer list.
 ///
 /// After semantic analysis, the initializer list will represent the
 /// semantic form of the initializer, where the initializations of all
 /// subobjects are made explicit with nested InitListExpr nodes and
 /// C99 designators have been eliminated by placing the designated
 /// initializations into the subobject they initialize. Additionally,
 /// any "holes" in the initialization, where no initializer has been
 /// specified for a particular subobject, will be replaced with
 /// implicitly-generated ImplicitValueInitExpr expressions that
 /// value-initialize the subobjects. Note, however, that the
 /// initializer lists may still have fewer initializers than there are
 /// elements to initialize within the object.
 ///
 /// After semantic analysis has completed, given an initializer list,
 /// method isSemanticForm() returns true if and only if this is the
 /// semantic form of the initializer list (note: the same AST node
 /// may at the same time be the syntactic form).
 /// Given the semantic form of the initializer list, one can retrieve
 /// the syntactic form of that initializer list (when different)
 /// using method getSyntacticForm(); the method returns null if applied
 /// to a initializer list which is already in syntactic form.
 /// Similarly, given the syntactic form (i.e., an initializer list such
 /// that isSemanticForm() returns false), one can retrieve the semantic
 /// form using method getSemanticForm().
 /// Since many initializer lists have the same syntactic and semantic forms,
 /// getSyntacticForm() may return NULL, indicating that the current
 /// semantic initializer list also serves as its syntactic form.
 class InitListExpr : public Expr {
   // FIXME: Eliminate this vector in favor of ASTContext allocation
   typedef ASTVector<Stmt *> InitExprsTy;
   InitExprsTy InitExprs;
   SourceLocation LBraceLoc, RBraceLoc;
 
   /// The alternative form of the initializer list (if it exists).
   /// The int part of the pair stores whether this initializer list is
   /// in semantic form. If not null, the pointer points to:
   ///   - the syntactic form, if this is in semantic form;
   ///   - the semantic form, if this is in syntactic form.
   llvm::PointerIntPair<InitListExpr *, 1, bool> AltForm;
 
   /// Either:
   ///  If this initializer list initializes an array with more elements than
   ///  there are initializers in the list, specifies an expression to be used
   ///  for value initialization of the rest of the elements.
   /// Or
   ///  If this initializer list initializes a union, specifies which
   ///  field within the union will be initialized.
   llvm::PointerUnion<Expr *, FieldDecl *> ArrayFillerOrUnionFieldInit;
 
 public:
   InitListExpr(const ASTContext &C, SourceLocation lbraceloc,
                ArrayRef<Expr*> initExprs, SourceLocation rbraceloc);
 
   /// Build an empty initializer list.
   explicit InitListExpr(EmptyShell Empty)
     : Expr(InitListExprClass, Empty), AltForm(nullptr, true) { }
 
   unsigned getNumInits() const { return InitExprs.size(); }
 
   /// Retrieve the set of initializers.
   Expr **getInits() { return reinterpret_cast<Expr **>(InitExprs.data()); }
 
   /// Retrieve the set of initializers.
   Expr * const *getInits() const {
     return reinterpret_cast<Expr * const *>(InitExprs.data());
   }
 
   ArrayRef<Expr *> inits() { return llvm::ArrayRef(getInits(), getNumInits()); }
 
   ArrayRef<Expr *> inits() const {
     return llvm::ArrayRef(getInits(), getNumInits());
   }
 
   const Expr *getInit(unsigned Init) const {
     assert(Init < getNumInits() && "Initializer access out of range!");
     return cast_or_null<Expr>(InitExprs[Init]);
   }
 
   Expr *getInit(unsigned Init) {
     assert(Init < getNumInits() && "Initializer access out of range!");
     return cast_or_null<Expr>(InitExprs[Init]);
   }
 
   void setInit(unsigned Init, Expr *expr) {
     assert(Init < getNumInits() && "Initializer access out of range!");
     InitExprs[Init] = expr;
 
     if (expr)
       setDependence(getDependence() | expr->getDependence());
   }
 
   /// Mark the semantic form of the InitListExpr as error when the semantic
   /// analysis fails.
   void markError() {
     assert(isSemanticForm());
     setDependence(getDependence() | ExprDependence::ErrorDependent);
   }
 
   /// Reserve space for some number of initializers.
   void reserveInits(const ASTContext &C, unsigned NumInits);
 
   /// Specify the number of initializers
   ///
   /// If there are more than @p NumInits initializers, the remaining
   /// initializers will be destroyed. If there are fewer than @p
   /// NumInits initializers, NULL expressions will be added for the
   /// unknown initializers.
   void resizeInits(const ASTContext &Context, unsigned NumInits);
 
   /// Updates the initializer at index @p Init with the new
   /// expression @p expr, and returns the old expression at that
   /// location.
   ///
   /// When @p Init is out of range for this initializer list, the
   /// initializer list will be extended with NULL expressions to
   /// accommodate the new entry.
   Expr *updateInit(const ASTContext &C, unsigned Init, Expr *expr);
 
   /// If this initializer list initializes an array with more elements
   /// than there are initializers in the list, specifies an expression to be
   /// used for value initialization of the rest of the elements.
   Expr *getArrayFiller() {
     return dyn_cast_if_present<Expr *>(ArrayFillerOrUnionFieldInit);
   }
   const Expr *getArrayFiller() const {
     return const_cast<InitListExpr *>(this)->getArrayFiller();
   }
   void setArrayFiller(Expr *filler);
 
   /// Return true if this is an array initializer and its array "filler"
   /// has been set.
   bool hasArrayFiller() const { return getArrayFiller(); }
 
   /// Determine whether this initializer list contains a designated initializer.
   bool hasDesignatedInit() const {
     return std::any_of(begin(), end(), [](const Stmt *S) {
       return isa<DesignatedInitExpr>(S);
     });
   }
 
   /// If this initializes a union, specifies which field in the
   /// union to initialize.
   ///
   /// Typically, this field is the first named field within the
   /// union. However, a designated initializer can specify the
   /// initialization of a different field within the union.
   FieldDecl *getInitializedFieldInUnion() {
     return dyn_cast_if_present<FieldDecl *>(ArrayFillerOrUnionFieldInit);
   }
   const FieldDecl *getInitializedFieldInUnion() const {
     return const_cast<InitListExpr *>(this)->getInitializedFieldInUnion();
   }
   void setInitializedFieldInUnion(FieldDecl *FD) {
     assert((FD == nullptr
             || getInitializedFieldInUnion() == nullptr
             || getInitializedFieldInUnion() == FD)
            && "Only one field of a union may be initialized at a time!");
     ArrayFillerOrUnionFieldInit = FD;
   }
 
   // Explicit InitListExpr's originate from source code (and have valid source
   // locations). Implicit InitListExpr's are created by the semantic analyzer.
   // FIXME: This is wrong; InitListExprs created by semantic analysis have
   // valid source locations too!
   bool isExplicit() const {
     return LBraceLoc.isValid() && RBraceLoc.isValid();
   }
 
   /// Is this an initializer for an array of characters, initialized by a string
   /// literal or an @encode?
   bool isStringLiteralInit() const;
 
   /// Is this a transparent initializer list (that is, an InitListExpr that is
   /// purely syntactic, and whose semantics are that of the sole contained
   /// initializer)?
   bool isTransparent() const;
 
   /// Is this the zero initializer {0} in a language which considers it
   /// idiomatic?
   bool isIdiomaticZeroInitializer(const LangOptions &LangOpts) const;
 
   SourceLocation getLBraceLoc() const { return LBraceLoc; }
   void setLBraceLoc(SourceLocation Loc) { LBraceLoc = Loc; }
   SourceLocation getRBraceLoc() const { return RBraceLoc; }
   void setRBraceLoc(SourceLocation Loc) { RBraceLoc = Loc; }
 
   bool isSemanticForm() const { return AltForm.getInt(); }
   InitListExpr *getSemanticForm() const {
     return isSemanticForm() ? nullptr : AltForm.getPointer();
   }
   bool isSyntacticForm() const {
     return !AltForm.getInt() || !AltForm.getPointer();
   }
   InitListExpr *getSyntacticForm() const {
     return isSemanticForm() ? AltForm.getPointer() : nullptr;
   }
 
   void setSyntacticForm(InitListExpr *Init) {
     AltForm.setPointer(Init);
     AltForm.setInt(true);
     Init->AltForm.setPointer(this);
     Init->AltForm.setInt(false);
   }
 
   bool hadArrayRangeDesignator() const {
     return InitListExprBits.HadArrayRangeDesignator != 0;
   }
   void sawArrayRangeDesignator(bool ARD = true) {
     InitListExprBits.HadArrayRangeDesignator = ARD;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == InitListExprClass;
   }
 
   // Iterators
   child_range children() {
     const_child_range CCR = const_cast<const InitListExpr *>(this)->children();
     return child_range(cast_away_const(CCR.begin()),
                        cast_away_const(CCR.end()));
   }
 
   const_child_range children() const {
     // FIXME: This does not include the array filler expression.
     if (InitExprs.empty())
       return const_child_range(const_child_iterator(), const_child_iterator());
     return const_child_range(&InitExprs[0], &InitExprs[0] + InitExprs.size());
   }
 
   typedef InitExprsTy::iterator iterator;
   typedef InitExprsTy::const_iterator const_iterator;
   typedef InitExprsTy::reverse_iterator reverse_iterator;
   typedef InitExprsTy::const_reverse_iterator const_reverse_iterator;
 
   iterator begin() { return InitExprs.begin(); }
   const_iterator begin() const { return InitExprs.begin(); }
   iterator end() { return InitExprs.end(); }
   const_iterator end() const { return InitExprs.end(); }
   reverse_iterator rbegin() { return InitExprs.rbegin(); }
   const_reverse_iterator rbegin() const { return InitExprs.rbegin(); }
   reverse_iterator rend() { return InitExprs.rend(); }
   const_reverse_iterator rend() const { return InitExprs.rend(); }
 
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 };
 
 /// Represents a C99 designated initializer expression.
 ///
 /// A designated initializer expression (C99 6.7.8) contains one or
 /// more designators (which can be field designators, array
 /// designators, or GNU array-range designators) followed by an
 /// expression that initializes the field or element(s) that the
 /// designators refer to. For example, given:
 ///
 /// @code
 /// struct point {
 ///   double x;
 ///   double y;
 /// };
 /// struct point ptarray[10] = { [2].y = 1.0, [2].x = 2.0, [0].x = 1.0 };
 /// @endcode
 ///
 /// The InitListExpr contains three DesignatedInitExprs, the first of
 /// which covers @c [2].y=1.0. This DesignatedInitExpr will have two
 /// designators, one array designator for @c [2] followed by one field
 /// designator for @c .y. The initialization expression will be 1.0.
 class DesignatedInitExpr final
     : public Expr,
       private llvm::TrailingObjects<DesignatedInitExpr, Stmt *> {
 public:
   /// Forward declaration of the Designator class.
   class Designator;
 
 private:
   /// The location of the '=' or ':' prior to the actual initializer
   /// expression.
   SourceLocation EqualOrColonLoc;
 
   /// Whether this designated initializer used the GNU deprecated
   /// syntax rather than the C99 '=' syntax.
   LLVM_PREFERRED_TYPE(bool)
   unsigned GNUSyntax : 1;
 
   /// The number of designators in this initializer expression.
   unsigned NumDesignators : 15;
 
   /// The number of subexpressions of this initializer expression,
   /// which contains both the initializer and any additional
   /// expressions used by array and array-range designators.
   unsigned NumSubExprs : 16;
 
   /// The designators in this designated initialization
   /// expression.
   Designator *Designators;
 
   DesignatedInitExpr(const ASTContext &C, QualType Ty,
                      llvm::ArrayRef<Designator> Designators,
                      SourceLocation EqualOrColonLoc, bool GNUSyntax,
                      ArrayRef<Expr *> IndexExprs, Expr *Init);
 
   explicit DesignatedInitExpr(unsigned NumSubExprs)
     : Expr(DesignatedInitExprClass, EmptyShell()),
       NumDesignators(0), NumSubExprs(NumSubExprs), Designators(nullptr) { }
 
 public:
   /// Represents a single C99 designator.
   ///
   /// @todo This class is infuriatingly similar to clang::Designator,
   /// but minor differences (storing indices vs. storing pointers)
   /// keep us from reusing it. Try harder, later, to rectify these
   /// differences.
   class Designator {
     /// A field designator, e.g., ".x".
     struct FieldDesignatorInfo {
       /// Refers to the field that is being initialized. The low bit
       /// of this field determines whether this is actually a pointer
       /// to an IdentifierInfo (if 1) or a FieldDecl (if 0). When
       /// initially constructed, a field designator will store an
       /// IdentifierInfo*. After semantic analysis has resolved that
       /// name, the field designator will instead store a FieldDecl*.
       uintptr_t NameOrField;
 
       /// The location of the '.' in the designated initializer.
       SourceLocation DotLoc;
 
       /// The location of the field name in the designated initializer.
       SourceLocation FieldLoc;
 
       FieldDesignatorInfo(const IdentifierInfo *II, SourceLocation DotLoc,
                           SourceLocation FieldLoc)
           : NameOrField(reinterpret_cast<uintptr_t>(II) | 0x1), DotLoc(DotLoc),
             FieldLoc(FieldLoc) {}
     };
 
     /// An array or GNU array-range designator, e.g., "[9]" or "[10...15]".
     struct ArrayOrRangeDesignatorInfo {
       /// Location of the first index expression within the designated
       /// initializer expression's list of subexpressions.
       unsigned Index;
 
       /// The location of the '[' starting the array range designator.
       SourceLocation LBracketLoc;
 
       /// The location of the ellipsis separating the start and end
       /// indices. Only valid for GNU array-range designators.
       SourceLocation EllipsisLoc;
 
       /// The location of the ']' terminating the array range designator.
       SourceLocation RBracketLoc;
 
       ArrayOrRangeDesignatorInfo(unsigned Index, SourceLocation LBracketLoc,
                                  SourceLocation RBracketLoc)
           : Index(Index), LBracketLoc(LBracketLoc), RBracketLoc(RBracketLoc) {}
 
       ArrayOrRangeDesignatorInfo(unsigned Index,
                                  SourceLocation LBracketLoc,
                                  SourceLocation EllipsisLoc,
                                  SourceLocation RBracketLoc)
           : Index(Index), LBracketLoc(LBracketLoc), EllipsisLoc(EllipsisLoc),
             RBracketLoc(RBracketLoc) {}
     };
 
     /// The kind of designator this describes.
     enum DesignatorKind {
       FieldDesignator,
       ArrayDesignator,
       ArrayRangeDesignator
     };
 
     DesignatorKind Kind;
 
     union {
       /// A field designator, e.g., ".x".
       struct FieldDesignatorInfo FieldInfo;
 
       /// An array or GNU array-range designator, e.g., "[9]" or "[10..15]".
       struct ArrayOrRangeDesignatorInfo ArrayOrRangeInfo;
     };
 
     Designator(DesignatorKind Kind) : Kind(Kind) {}
 
   public:
     Designator() {}
 
     bool isFieldDesignator() const { return Kind == FieldDesignator; }
     bool isArrayDesignator() const { return Kind == ArrayDesignator; }
     bool isArrayRangeDesignator() const { return Kind == ArrayRangeDesignator; }
 
     //===------------------------------------------------------------------===//
     // FieldDesignatorInfo
 
     /// Creates a field designator.
     static Designator CreateFieldDesignator(const IdentifierInfo *FieldName,
                                             SourceLocation DotLoc,
                                             SourceLocation FieldLoc) {
       Designator D(FieldDesignator);
       new (&D.FieldInfo) FieldDesignatorInfo(FieldName, DotLoc, FieldLoc);
       return D;
     }
 
     const IdentifierInfo *getFieldName() const;
 
     FieldDecl *getFieldDecl() const {
       assert(isFieldDesignator() && "Only valid on a field designator");
       if (FieldInfo.NameOrField & 0x01)
         return nullptr;
       return reinterpret_cast<FieldDecl *>(FieldInfo.NameOrField);
     }
 
     void setFieldDecl(FieldDecl *FD) {
       assert(isFieldDesignator() && "Only valid on a field designator");
       FieldInfo.NameOrField = reinterpret_cast<uintptr_t>(FD);
     }
 
     SourceLocation getDotLoc() const {
       assert(isFieldDesignator() && "Only valid on a field designator");
       return FieldInfo.DotLoc;
     }
 
     SourceLocation getFieldLoc() const {
       assert(isFieldDesignator() && "Only valid on a field designator");
       return FieldInfo.FieldLoc;
     }
 
     //===------------------------------------------------------------------===//
     // ArrayOrRangeDesignator
 
     /// Creates an array designator.
     static Designator CreateArrayDesignator(unsigned Index,
                                             SourceLocation LBracketLoc,
                                             SourceLocation RBracketLoc) {
       Designator D(ArrayDesignator);
       new (&D.ArrayOrRangeInfo) ArrayOrRangeDesignatorInfo(Index, LBracketLoc,
                                                            RBracketLoc);
       return D;
     }
 
     /// Creates a GNU array-range designator.
     static Designator CreateArrayRangeDesignator(unsigned Index,
                                                  SourceLocation LBracketLoc,
                                                  SourceLocation EllipsisLoc,
                                                  SourceLocation RBracketLoc) {
       Designator D(ArrayRangeDesignator);
       new (&D.ArrayOrRangeInfo) ArrayOrRangeDesignatorInfo(Index, LBracketLoc,
                                                            EllipsisLoc,
                                                            RBracketLoc);
       return D;
     }
 
     unsigned getArrayIndex() const {
       assert((isArrayDesignator() || isArrayRangeDesignator()) &&
              "Only valid on an array or array-range designator");
       return ArrayOrRangeInfo.Index;
     }
 
     SourceLocation getLBracketLoc() const {
       assert((isArrayDesignator() || isArrayRangeDesignator()) &&
              "Only valid on an array or array-range designator");
       return ArrayOrRangeInfo.LBracketLoc;
     }
 
     SourceLocation getEllipsisLoc() const {
       assert(isArrayRangeDesignator() &&
              "Only valid on an array-range designator");
       return ArrayOrRangeInfo.EllipsisLoc;
     }
 
     SourceLocation getRBracketLoc() const {
       assert((isArrayDesignator() || isArrayRangeDesignator()) &&
              "Only valid on an array or array-range designator");
       return ArrayOrRangeInfo.RBracketLoc;
     }
 
     SourceLocation getBeginLoc() const LLVM_READONLY {
       if (isFieldDesignator())
         return getDotLoc().isInvalid() ? getFieldLoc() : getDotLoc();
       return getLBracketLoc();
     }
 
     SourceLocation getEndLoc() const LLVM_READONLY {
       return isFieldDesignator() ? getFieldLoc() : getRBracketLoc();
     }
 
     SourceRange getSourceRange() const LLVM_READONLY {
       return SourceRange(getBeginLoc(), getEndLoc());
     }
   };
 
   static DesignatedInitExpr *Create(const ASTContext &C,
                                     llvm::ArrayRef<Designator> Designators,
                                     ArrayRef<Expr*> IndexExprs,
                                     SourceLocation EqualOrColonLoc,
                                     bool GNUSyntax, Expr *Init);
 
   static DesignatedInitExpr *CreateEmpty(const ASTContext &C,
                                          unsigned NumIndexExprs);
 
   /// Returns the number of designators in this initializer.
   unsigned size() const { return NumDesignators; }
 
   // Iterator access to the designators.
   llvm::MutableArrayRef<Designator> designators() {
     return {Designators, NumDesignators};
   }
 
   llvm::ArrayRef<Designator> designators() const {
     return {Designators, NumDesignators};
   }
 
   Designator *getDesignator(unsigned Idx) { return &designators()[Idx]; }
   const Designator *getDesignator(unsigned Idx) const {
     return &designators()[Idx];
   }
 
   void setDesignators(const ASTContext &C, const Designator *Desigs,
                       unsigned NumDesigs);
 
   Expr *getArrayIndex(const Designator &D) const;
   Expr *getArrayRangeStart(const Designator &D) const;
   Expr *getArrayRangeEnd(const Designator &D) const;
 
   /// Retrieve the location of the '=' that precedes the
   /// initializer value itself, if present.
   SourceLocation getEqualOrColonLoc() const { return EqualOrColonLoc; }
   void setEqualOrColonLoc(SourceLocation L) { EqualOrColonLoc = L; }
 
   /// Whether this designated initializer should result in direct-initialization
   /// of the designated subobject (eg, '{.foo{1, 2, 3}}').
   bool isDirectInit() const { return EqualOrColonLoc.isInvalid(); }
 
   /// Determines whether this designated initializer used the
   /// deprecated GNU syntax for designated initializers.
   bool usesGNUSyntax() const { return GNUSyntax; }
   void setGNUSyntax(bool GNU) { GNUSyntax = GNU; }
 
   /// Retrieve the initializer value.
   Expr *getInit() const {
     return cast<Expr>(*const_cast<DesignatedInitExpr*>(this)->child_begin());
   }
 
   void setInit(Expr *init) {
     *child_begin() = init;
   }
 
   /// Retrieve the total number of subexpressions in this
   /// designated initializer expression, including the actual
   /// initialized value and any expressions that occur within array
   /// and array-range designators.
   unsigned getNumSubExprs() const { return NumSubExprs; }
 
   Expr *getSubExpr(unsigned Idx) const {
     assert(Idx < NumSubExprs && "Subscript out of range");
     return cast<Expr>(getTrailingObjects<Stmt *>()[Idx]);
   }
 
   void setSubExpr(unsigned Idx, Expr *E) {
     assert(Idx < NumSubExprs && "Subscript out of range");
     getTrailingObjects<Stmt *>()[Idx] = E;
   }
 
   /// Replaces the designator at index @p Idx with the series
   /// of designators in [First, Last).
   void ExpandDesignator(const ASTContext &C, unsigned Idx,
                         const Designator *First, const Designator *Last);
 
   SourceRange getDesignatorsSourceRange() const;
 
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == DesignatedInitExprClass;
   }
 
   // Iterators
   child_range children() {
     Stmt **begin = getTrailingObjects<Stmt *>();
     return child_range(begin, begin + NumSubExprs);
   }
   const_child_range children() const {
     Stmt * const *begin = getTrailingObjects<Stmt *>();
     return const_child_range(begin, begin + NumSubExprs);
   }
 
   friend TrailingObjects;
 };
 
 /// Represents a place-holder for an object not to be initialized by
 /// anything.
 ///
 /// This only makes sense when it appears as part of an updater of a
 /// DesignatedInitUpdateExpr (see below). The base expression of a DIUE
 /// initializes a big object, and the NoInitExpr's mark the spots within the
 /// big object not to be overwritten by the updater.
 ///
 /// \see DesignatedInitUpdateExpr
 class NoInitExpr : public Expr {
 public:
   explicit NoInitExpr(QualType ty)
       : Expr(NoInitExprClass, ty, VK_PRValue, OK_Ordinary) {
     setDependence(computeDependence(this));
   }
 
   explicit NoInitExpr(EmptyShell Empty)
     : Expr(NoInitExprClass, Empty) { }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == NoInitExprClass;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return SourceLocation(); }
   SourceLocation getEndLoc() const LLVM_READONLY { return SourceLocation(); }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 // In cases like:
 //   struct Q { int a, b, c; };
 //   Q *getQ();
 //   void foo() {
 //     struct A { Q q; } a = { *getQ(), .q.b = 3 };
 //   }
 //
 // We will have an InitListExpr for a, with type A, and then a
 // DesignatedInitUpdateExpr for "a.q" with type Q. The "base" for this DIUE
 // is the call expression *getQ(); the "updater" for the DIUE is ".q.b = 3"
 //
 class DesignatedInitUpdateExpr : public Expr {
   // BaseAndUpdaterExprs[0] is the base expression;
   // BaseAndUpdaterExprs[1] is an InitListExpr overwriting part of the base.
   Stmt *BaseAndUpdaterExprs[2];
 
 public:
   DesignatedInitUpdateExpr(const ASTContext &C, SourceLocation lBraceLoc,
                            Expr *baseExprs, SourceLocation rBraceLoc);
 
   explicit DesignatedInitUpdateExpr(EmptyShell Empty)
     : Expr(DesignatedInitUpdateExprClass, Empty) { }
 
   SourceLocation getBeginLoc() const LLVM_READONLY;
   SourceLocation getEndLoc() const LLVM_READONLY;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == DesignatedInitUpdateExprClass;
   }
 
   Expr *getBase() const { return cast<Expr>(BaseAndUpdaterExprs[0]); }
   void setBase(Expr *Base) { BaseAndUpdaterExprs[0] = Base; }
 
   InitListExpr *getUpdater() const {
     return cast<InitListExpr>(BaseAndUpdaterExprs[1]);
   }
   void setUpdater(Expr *Updater) { BaseAndUpdaterExprs[1] = Updater; }
 
   // Iterators
   // children = the base and the updater
   child_range children() {
     return child_range(&BaseAndUpdaterExprs[0], &BaseAndUpdaterExprs[0] + 2);
   }
   const_child_range children() const {
     return const_child_range(&BaseAndUpdaterExprs[0],
                              &BaseAndUpdaterExprs[0] + 2);
   }
 };
 
 /// Represents a loop initializing the elements of an array.
 ///
 /// The need to initialize the elements of an array occurs in a number of
 /// contexts:
 ///
 ///  * in the implicit copy/move constructor for a class with an array member
 ///  * when a lambda-expression captures an array by value
 ///  * when a decomposition declaration decomposes an array
 ///
 /// There are two subexpressions: a common expression (the source array)
 /// that is evaluated once up-front, and a per-element initializer that
 /// runs once for each array element.
 ///
 /// Within the per-element initializer, the common expression may be referenced
 /// via an OpaqueValueExpr, and the current index may be obtained via an
 /// ArrayInitIndexExpr.
 class ArrayInitLoopExpr : public Expr {
   Stmt *SubExprs[2];
 
   explicit ArrayInitLoopExpr(EmptyShell Empty)
       : Expr(ArrayInitLoopExprClass, Empty), SubExprs{} {}
 
 public:
   explicit ArrayInitLoopExpr(QualType T, Expr *CommonInit, Expr *ElementInit)
       : Expr(ArrayInitLoopExprClass, T, VK_PRValue, OK_Ordinary),
         SubExprs{CommonInit, ElementInit} {
     setDependence(computeDependence(this));
   }
 
   /// Get the common subexpression shared by all initializations (the source
   /// array).
   OpaqueValueExpr *getCommonExpr() const {
     return cast<OpaqueValueExpr>(SubExprs[0]);
   }
 
   /// Get the initializer to use for each array element.
   Expr *getSubExpr() const { return cast<Expr>(SubExprs[1]); }
 
   llvm::APInt getArraySize() const {
     return cast<ConstantArrayType>(getType()->castAsArrayTypeUnsafe())
         ->getSize();
   }
 
   static bool classof(const Stmt *S) {
     return S->getStmtClass() == ArrayInitLoopExprClass;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getCommonExpr()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getCommonExpr()->getEndLoc();
   }
 
   child_range children() {
     return child_range(SubExprs, SubExprs + 2);
   }
   const_child_range children() const {
     return const_child_range(SubExprs, SubExprs + 2);
   }
 
   friend class ASTReader;
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 };
 
 /// Represents the index of the current element of an array being
 /// initialized by an ArrayInitLoopExpr. This can only appear within the
 /// subexpression of an ArrayInitLoopExpr.
 class ArrayInitIndexExpr : public Expr {
   explicit ArrayInitIndexExpr(EmptyShell Empty)
       : Expr(ArrayInitIndexExprClass, Empty) {}
 
 public:
   explicit ArrayInitIndexExpr(QualType T)
       : Expr(ArrayInitIndexExprClass, T, VK_PRValue, OK_Ordinary) {
     setDependence(ExprDependence::None);
   }
 
   static bool classof(const Stmt *S) {
     return S->getStmtClass() == ArrayInitIndexExprClass;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return SourceLocation(); }
   SourceLocation getEndLoc() const LLVM_READONLY { return SourceLocation(); }
 
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   friend class ASTReader;
   friend class ASTStmtReader;
 };
 
 /// Represents an implicitly-generated value initialization of
 /// an object of a given type.
 ///
 /// Implicit value initializations occur within semantic initializer
 /// list expressions (InitListExpr) as placeholders for subobject
 /// initializations not explicitly specified by the user.
 ///
 /// \see InitListExpr
 class ImplicitValueInitExpr : public Expr {
 public:
   explicit ImplicitValueInitExpr(QualType ty)
       : Expr(ImplicitValueInitExprClass, ty, VK_PRValue, OK_Ordinary) {
     setDependence(computeDependence(this));
   }
 
   /// Construct an empty implicit value initialization.
   explicit ImplicitValueInitExpr(EmptyShell Empty)
     : Expr(ImplicitValueInitExprClass, Empty) { }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ImplicitValueInitExprClass;
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return SourceLocation(); }
   SourceLocation getEndLoc() const LLVM_READONLY { return SourceLocation(); }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 class ParenListExpr final
     : public Expr,
       private llvm::TrailingObjects<ParenListExpr, Stmt *> {
   friend class ASTStmtReader;
   friend TrailingObjects;
 
   /// The location of the left and right parentheses.
   SourceLocation LParenLoc, RParenLoc;
 
   /// Build a paren list.
   ParenListExpr(SourceLocation LParenLoc, ArrayRef<Expr *> Exprs,
                 SourceLocation RParenLoc);
 
   /// Build an empty paren list.
   ParenListExpr(EmptyShell Empty, unsigned NumExprs);
 
 public:
   /// Create a paren list.
   static ParenListExpr *Create(const ASTContext &Ctx, SourceLocation LParenLoc,
                                ArrayRef<Expr *> Exprs,
                                SourceLocation RParenLoc);
 
   /// Create an empty paren list.
   static ParenListExpr *CreateEmpty(const ASTContext &Ctx, unsigned NumExprs);
 
   /// Return the number of expressions in this paren list.
   unsigned getNumExprs() const { return ParenListExprBits.NumExprs; }
 
   Expr *getExpr(unsigned Init) {
     assert(Init < getNumExprs() && "Initializer access out of range!");
     return getExprs()[Init];
   }
 
   const Expr *getExpr(unsigned Init) const {
     return const_cast<ParenListExpr *>(this)->getExpr(Init);
   }
 
   Expr **getExprs() {
     return reinterpret_cast<Expr **>(getTrailingObjects<Stmt *>());
   }
 
   ArrayRef<Expr *> exprs() { return llvm::ArrayRef(getExprs(), getNumExprs()); }
 
   SourceLocation getLParenLoc() const { return LParenLoc; }
   SourceLocation getRParenLoc() const { return RParenLoc; }
   SourceLocation getBeginLoc() const { return getLParenLoc(); }
   SourceLocation getEndLoc() const { return getRParenLoc(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ParenListExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(getTrailingObjects<Stmt *>(),
                        getTrailingObjects<Stmt *>() + getNumExprs());
   }
   const_child_range children() const {
     return const_child_range(getTrailingObjects<Stmt *>(),
                              getTrailingObjects<Stmt *>() + getNumExprs());
   }
 };
 
 /// Represents a C11 generic selection.
 ///
 /// A generic selection (C11 6.5.1.1) contains an unevaluated controlling
 /// expression, followed by one or more generic associations.  Each generic
 /// association specifies a type name and an expression, or "default" and an
 /// expression (in which case it is known as a default generic association).
 /// The type and value of the generic selection are identical to those of its
 /// result expression, which is defined as the expression in the generic
 /// association with a type name that is compatible with the type of the
 /// controlling expression, or the expression in the default generic association
 /// if no types are compatible.  For example:
 ///
 /// @code
 /// _Generic(X, double: 1, float: 2, default: 3)
 /// @endcode
 ///
 /// The above expression evaluates to 1 if 1.0 is substituted for X, 2 if 1.0f
 /// or 3 if "hello".
 ///
 /// As an extension, generic selections are allowed in C++, where the following
 /// additional semantics apply:
 ///
 /// Any generic selection whose controlling expression is type-dependent or
 /// which names a dependent type in its association list is result-dependent,
 /// which means that the choice of result expression is dependent.
 /// Result-dependent generic associations are both type- and value-dependent.
 ///
 /// We also allow an extended form in both C and C++ where the controlling
 /// predicate for the selection expression is a type rather than an expression.
 /// This type argument form does not perform any conversions for the
 /// controlling type, which makes it suitable for use with qualified type
 /// associations, which is not possible with the expression form.
 class GenericSelectionExpr final
     : public Expr,
       private llvm::TrailingObjects<GenericSelectionExpr, Stmt *,
                                     TypeSourceInfo *> {
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
   friend TrailingObjects;
 
   /// The number of association expressions and the index of the result
   /// expression in the case where the generic selection expression is not
   /// result-dependent. The result index is equal to ResultDependentIndex
   /// if and only if the generic selection expression is result-dependent.
   unsigned NumAssocs : 15;
   unsigned ResultIndex : 15; // NB: ResultDependentIndex is tied to this width.
   LLVM_PREFERRED_TYPE(bool)
   unsigned IsExprPredicate : 1;
   enum : unsigned {
     ResultDependentIndex = 0x7FFF
   };
 
   unsigned getIndexOfControllingExpression() const {
     // If controlled by an expression, the first offset into the Stmt *
     // trailing array is the controlling expression, the associated expressions
     // follow this.
     assert(isExprPredicate() && "Asking for the controlling expression of a "
                                 "selection expr predicated by a type");
     return 0;
   }
 
   unsigned getIndexOfControllingType() const {
     // If controlled by a type, the first offset into the TypeSourceInfo *
     // trailing array is the controlling type, the associated types follow this.
     assert(isTypePredicate() && "Asking for the controlling type of a "
                                  "selection expr predicated by an expression");
     return 0;
   }
 
   unsigned getIndexOfStartOfAssociatedExprs() const {
     // If the predicate is a type, then the associated expressions are the only
     // Stmt * in the trailing array, otherwise we need to offset past the
     // predicate expression.
     return (int)isExprPredicate();
   }
 
   unsigned getIndexOfStartOfAssociatedTypes() const {
     // If the predicate is a type, then the associated types follow it in the
     // trailing array. Otherwise, the associated types are the only
     // TypeSourceInfo * in the trailing array.
     return (int)isTypePredicate();
   }
 
 
   /// The location of the "default" and of the right parenthesis.
   SourceLocation DefaultLoc, RParenLoc;
 
   // GenericSelectionExpr is followed by several trailing objects.
   // They are (in order):
   //
   // * A single Stmt * for the controlling expression or a TypeSourceInfo * for
   //   the controlling type, depending on the result of isTypePredicate() or
   //   isExprPredicate().
   // * An array of getNumAssocs() Stmt * for the association expressions.
   // * An array of getNumAssocs() TypeSourceInfo *, one for each of the
   //   association expressions.
   unsigned numTrailingObjects(OverloadToken<Stmt *>) const {
     // Add one to account for the controlling expression; the remainder
     // are the associated expressions.
     return getNumAssocs() + (int)isExprPredicate();
   }
 
   unsigned numTrailingObjects(OverloadToken<TypeSourceInfo *>) const {
     // Add one to account for the controlling type predicate, the remainder
     // are the associated types.
     return getNumAssocs() + (int)isTypePredicate();
   }
 
   template <bool Const> class AssociationIteratorTy;
   /// Bundle together an association expression and its TypeSourceInfo.
   /// The Const template parameter is for the const and non-const versions
   /// of AssociationTy.
   template <bool Const> class AssociationTy {
     friend class GenericSelectionExpr;
     template <bool OtherConst> friend class AssociationIteratorTy;
     using ExprPtrTy = std::conditional_t<Const, const Expr *, Expr *>;
     using TSIPtrTy =
         std::conditional_t<Const, const TypeSourceInfo *, TypeSourceInfo *>;
     ExprPtrTy E;
     TSIPtrTy TSI;
     bool Selected;
     AssociationTy(ExprPtrTy E, TSIPtrTy TSI, bool Selected)
         : E(E), TSI(TSI), Selected(Selected) {}
 
   public:
     ExprPtrTy getAssociationExpr() const { return E; }
     TSIPtrTy getTypeSourceInfo() const { return TSI; }
     QualType getType() const { return TSI ? TSI->getType() : QualType(); }
     bool isSelected() const { return Selected; }
     AssociationTy *operator->() { return this; }
     const AssociationTy *operator->() const { return this; }
   }; // class AssociationTy
 
   /// Iterator over const and non-const Association objects. The Association
   /// objects are created on the fly when the iterator is dereferenced.
   /// This abstract over how exactly the association expressions and the
   /// corresponding TypeSourceInfo * are stored.
   template <bool Const>
   class AssociationIteratorTy
       : public llvm::iterator_facade_base<
             AssociationIteratorTy<Const>, std::input_iterator_tag,
             AssociationTy<Const>, std::ptrdiff_t, AssociationTy<Const>,
             AssociationTy<Const>> {
     friend class GenericSelectionExpr;
     // FIXME: This iterator could conceptually be a random access iterator, and
     // it would be nice if we could strengthen the iterator category someday.
     // However this iterator does not satisfy two requirements of forward
     // iterators:
     // a) reference = T& or reference = const T&
     // b) If It1 and It2 are both dereferenceable, then It1 == It2 if and only
     //    if *It1 and *It2 are bound to the same objects.
     // An alternative design approach was discussed during review;
     // store an Association object inside the iterator, and return a reference
     // to it when dereferenced. This idea was discarded because of nasty
     // lifetime issues:
     //    AssociationIterator It = ...;
     //    const Association &Assoc = *It++; // Oops, Assoc is dangling.
     using BaseTy = typename AssociationIteratorTy::iterator_facade_base;
     using StmtPtrPtrTy =
         std::conditional_t<Const, const Stmt *const *, Stmt **>;
     using TSIPtrPtrTy = std::conditional_t<Const, const TypeSourceInfo *const *,
                                            TypeSourceInfo **>;
     StmtPtrPtrTy E = nullptr;
     TSIPtrPtrTy TSI; // Kept in sync with E.
     unsigned Offset = 0, SelectedOffset = 0;
     AssociationIteratorTy(StmtPtrPtrTy E, TSIPtrPtrTy TSI, unsigned Offset,
                           unsigned SelectedOffset)
         : E(E), TSI(TSI), Offset(Offset), SelectedOffset(SelectedOffset) {}
 
   public:
     AssociationIteratorTy() : E(nullptr), TSI(nullptr) {}
     typename BaseTy::reference operator*() const {
       return AssociationTy<Const>(cast<Expr>(*E), *TSI,
                                   Offset == SelectedOffset);
     }
     typename BaseTy::pointer operator->() const { return **this; }
     using BaseTy::operator++;
     AssociationIteratorTy &operator++() {
       ++E;
       ++TSI;
       ++Offset;
       return *this;
     }
     bool operator==(AssociationIteratorTy Other) const { return E == Other.E; }
   }; // class AssociationIterator
 
   /// Build a non-result-dependent generic selection expression accepting an
   /// expression predicate.
   GenericSelectionExpr(const ASTContext &Context, SourceLocation GenericLoc,
                        Expr *ControllingExpr,
                        ArrayRef<TypeSourceInfo *> AssocTypes,
                        ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
                        SourceLocation RParenLoc,
                        bool ContainsUnexpandedParameterPack,
                        unsigned ResultIndex);
 
   /// Build a result-dependent generic selection expression accepting an
   /// expression predicate.
   GenericSelectionExpr(const ASTContext &Context, SourceLocation GenericLoc,
                        Expr *ControllingExpr,
                        ArrayRef<TypeSourceInfo *> AssocTypes,
                        ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
                        SourceLocation RParenLoc,
                        bool ContainsUnexpandedParameterPack);
 
   /// Build a non-result-dependent generic selection expression accepting a
   /// type predicate.
   GenericSelectionExpr(const ASTContext &Context, SourceLocation GenericLoc,
                        TypeSourceInfo *ControllingType,
                        ArrayRef<TypeSourceInfo *> AssocTypes,
                        ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
                        SourceLocation RParenLoc,
                        bool ContainsUnexpandedParameterPack,
                        unsigned ResultIndex);
 
   /// Build a result-dependent generic selection expression accepting a type
   /// predicate.
   GenericSelectionExpr(const ASTContext &Context, SourceLocation GenericLoc,
                        TypeSourceInfo *ControllingType,
                        ArrayRef<TypeSourceInfo *> AssocTypes,
                        ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
                        SourceLocation RParenLoc,
                        bool ContainsUnexpandedParameterPack);
 
   /// Build an empty generic selection expression for deserialization.
   explicit GenericSelectionExpr(EmptyShell Empty, unsigned NumAssocs);
 
 public:
   /// Create a non-result-dependent generic selection expression accepting an
   /// expression predicate.
   static GenericSelectionExpr *
   Create(const ASTContext &Context, SourceLocation GenericLoc,
          Expr *ControllingExpr, ArrayRef<TypeSourceInfo *> AssocTypes,
          ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
          SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack,
          unsigned ResultIndex);
 
   /// Create a result-dependent generic selection expression accepting an
   /// expression predicate.
   static GenericSelectionExpr *
   Create(const ASTContext &Context, SourceLocation GenericLoc,
          Expr *ControllingExpr, ArrayRef<TypeSourceInfo *> AssocTypes,
          ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
          SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack);
 
   /// Create a non-result-dependent generic selection expression accepting a
   /// type predicate.
   static GenericSelectionExpr *
   Create(const ASTContext &Context, SourceLocation GenericLoc,
          TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
          ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
          SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack,
          unsigned ResultIndex);
 
   /// Create a result-dependent generic selection expression accepting a type
   /// predicate
   static GenericSelectionExpr *
   Create(const ASTContext &Context, SourceLocation GenericLoc,
          TypeSourceInfo *ControllingType, ArrayRef<TypeSourceInfo *> AssocTypes,
          ArrayRef<Expr *> AssocExprs, SourceLocation DefaultLoc,
          SourceLocation RParenLoc, bool ContainsUnexpandedParameterPack);
 
   /// Create an empty generic selection expression for deserialization.
   static GenericSelectionExpr *CreateEmpty(const ASTContext &Context,
                                            unsigned NumAssocs);
 
   using Association = AssociationTy<false>;
   using ConstAssociation = AssociationTy<true>;
   using AssociationIterator = AssociationIteratorTy<false>;
   using ConstAssociationIterator = AssociationIteratorTy<true>;
   using association_range = llvm::iterator_range<AssociationIterator>;
   using const_association_range =
       llvm::iterator_range<ConstAssociationIterator>;
 
   /// The number of association expressions.
   unsigned getNumAssocs() const { return NumAssocs; }
 
   /// The zero-based index of the result expression's generic association in
   /// the generic selection's association list.  Defined only if the
   /// generic selection is not result-dependent.
   unsigned getResultIndex() const {
     assert(!isResultDependent() &&
            "Generic selection is result-dependent but getResultIndex called!");
     return ResultIndex;
   }
 
   /// Whether this generic selection is result-dependent.
   bool isResultDependent() const { return ResultIndex == ResultDependentIndex; }
 
   /// Whether this generic selection uses an expression as its controlling
   /// argument.
   bool isExprPredicate() const { return IsExprPredicate; }
   /// Whether this generic selection uses a type as its controlling argument.
   bool isTypePredicate() const { return !IsExprPredicate; }
 
   /// Return the controlling expression of this generic selection expression.
   /// Only valid to call if the selection expression used an expression as its
   /// controlling argument.
   Expr *getControllingExpr() {
     return cast<Expr>(
         getTrailingObjects<Stmt *>()[getIndexOfControllingExpression()]);
   }
   const Expr *getControllingExpr() const {
     return cast<Expr>(
         getTrailingObjects<Stmt *>()[getIndexOfControllingExpression()]);
   }
 
   /// Return the controlling type of this generic selection expression. Only
   /// valid to call if the selection expression used a type as its controlling
   /// argument.
   TypeSourceInfo *getControllingType() {
     return getTrailingObjects<TypeSourceInfo *>()[getIndexOfControllingType()];
   }
   const TypeSourceInfo* getControllingType() const {
     return getTrailingObjects<TypeSourceInfo *>()[getIndexOfControllingType()];
   }
 
   /// Return the result expression of this controlling expression. Defined if
   /// and only if the generic selection expression is not result-dependent.
   Expr *getResultExpr() {
     return cast<Expr>(
         getTrailingObjects<Stmt *>()[getIndexOfStartOfAssociatedExprs() +
                                      getResultIndex()]);
   }
   const Expr *getResultExpr() const {
     return cast<Expr>(
         getTrailingObjects<Stmt *>()[getIndexOfStartOfAssociatedExprs() +
                                      getResultIndex()]);
   }
 
   ArrayRef<Expr *> getAssocExprs() const {
     return {reinterpret_cast<Expr *const *>(getTrailingObjects<Stmt *>() +
                                             getIndexOfStartOfAssociatedExprs()),
             NumAssocs};
   }
   ArrayRef<TypeSourceInfo *> getAssocTypeSourceInfos() const {
     return {getTrailingObjects<TypeSourceInfo *>() +
                 getIndexOfStartOfAssociatedTypes(),
             NumAssocs};
   }
 
   /// Return the Ith association expression with its TypeSourceInfo,
   /// bundled together in GenericSelectionExpr::(Const)Association.
   Association getAssociation(unsigned I) {
     assert(I < getNumAssocs() &&
            "Out-of-range index in GenericSelectionExpr::getAssociation!");
     return Association(
         cast<Expr>(
             getTrailingObjects<Stmt *>()[getIndexOfStartOfAssociatedExprs() +
                                          I]),
         getTrailingObjects<
             TypeSourceInfo *>()[getIndexOfStartOfAssociatedTypes() + I],
         !isResultDependent() && (getResultIndex() == I));
   }
   ConstAssociation getAssociation(unsigned I) const {
     assert(I < getNumAssocs() &&
            "Out-of-range index in GenericSelectionExpr::getAssociation!");
     return ConstAssociation(
         cast<Expr>(
             getTrailingObjects<Stmt *>()[getIndexOfStartOfAssociatedExprs() +
                                          I]),
         getTrailingObjects<
             TypeSourceInfo *>()[getIndexOfStartOfAssociatedTypes() + I],
         !isResultDependent() && (getResultIndex() == I));
   }
 
   association_range associations() {
     AssociationIterator Begin(getTrailingObjects<Stmt *>() +
                                   getIndexOfStartOfAssociatedExprs(),
                               getTrailingObjects<TypeSourceInfo *>() +
                                   getIndexOfStartOfAssociatedTypes(),
                               /*Offset=*/0, ResultIndex);
     AssociationIterator End(Begin.E + NumAssocs, Begin.TSI + NumAssocs,
                             /*Offset=*/NumAssocs, ResultIndex);
     return llvm::make_range(Begin, End);
   }
 
   const_association_range associations() const {
     ConstAssociationIterator Begin(getTrailingObjects<Stmt *>() +
                                        getIndexOfStartOfAssociatedExprs(),
                                    getTrailingObjects<TypeSourceInfo *>() +
                                        getIndexOfStartOfAssociatedTypes(),
                                    /*Offset=*/0, ResultIndex);
     ConstAssociationIterator End(Begin.E + NumAssocs, Begin.TSI + NumAssocs,
                                  /*Offset=*/NumAssocs, ResultIndex);
     return llvm::make_range(Begin, End);
   }
 
   SourceLocation getGenericLoc() const {
     return GenericSelectionExprBits.GenericLoc;
   }
   SourceLocation getDefaultLoc() const { return DefaultLoc; }
   SourceLocation getRParenLoc() const { return RParenLoc; }
   SourceLocation getBeginLoc() const { return getGenericLoc(); }
   SourceLocation getEndLoc() const { return getRParenLoc(); }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == GenericSelectionExprClass;
   }
 
   child_range children() {
     return child_range(getTrailingObjects<Stmt *>(),
                        getTrailingObjects<Stmt *>() +
                            numTrailingObjects(OverloadToken<Stmt *>()));
   }
   const_child_range children() const {
     return const_child_range(getTrailingObjects<Stmt *>(),
                              getTrailingObjects<Stmt *>() +
                                  numTrailingObjects(OverloadToken<Stmt *>()));
   }
 };
 
 //===----------------------------------------------------------------------===//
 // Clang Extensions
 //===----------------------------------------------------------------------===//
 
 /// ExtVectorElementExpr - This represents access to specific elements of a
 /// vector, and may occur on the left hand side or right hand side.  For example
 /// the following is legal:  "V.xy = V.zw" if V is a 4 element extended vector.
 ///
 /// Note that the base may have either vector or pointer to vector type, just
 /// like a struct field reference.
 ///
 class ExtVectorElementExpr : public Expr {
   Stmt *Base;
   IdentifierInfo *Accessor;
   SourceLocation AccessorLoc;
 public:
   ExtVectorElementExpr(QualType ty, ExprValueKind VK, Expr *base,
                        IdentifierInfo &accessor, SourceLocation loc)
       : Expr(ExtVectorElementExprClass, ty, VK,
              (VK == VK_PRValue ? OK_Ordinary : OK_VectorComponent)),
         Base(base), Accessor(&accessor), AccessorLoc(loc) {
     setDependence(computeDependence(this));
   }
 
   /// Build an empty vector element expression.
   explicit ExtVectorElementExpr(EmptyShell Empty)
     : Expr(ExtVectorElementExprClass, Empty) { }
 
   const Expr *getBase() const { return cast<Expr>(Base); }
   Expr *getBase() { return cast<Expr>(Base); }
   void setBase(Expr *E) { Base = E; }
 
   IdentifierInfo &getAccessor() const { return *Accessor; }
   void setAccessor(IdentifierInfo *II) { Accessor = II; }
 
   SourceLocation getAccessorLoc() const { return AccessorLoc; }
   void setAccessorLoc(SourceLocation L) { AccessorLoc = L; }
 
   /// getNumElements - Get the number of components being selected.
   unsigned getNumElements() const;
 
   /// containsDuplicateElements - Return true if any element access is
   /// repeated.
   bool containsDuplicateElements() const;
 
   /// getEncodedElementAccess - Encode the elements accessed into an llvm
   /// aggregate Constant of ConstantInt(s).
   void getEncodedElementAccess(SmallVectorImpl<uint32_t> &Elts) const;
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getBase()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY { return AccessorLoc; }
 
   /// isArrow - Return true if the base expression is a pointer to vector,
   /// return false if the base expression is a vector.
   bool isArrow() const;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ExtVectorElementExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&Base, &Base+1); }
   const_child_range children() const {
     return const_child_range(&Base, &Base + 1);
   }
 };
 
 /// BlockExpr - Adaptor class for mixing a BlockDecl with expressions.
 /// ^{ statement-body }   or   ^(int arg1, float arg2){ statement-body }
 class BlockExpr : public Expr {
 protected:
   BlockDecl *TheBlock;
 public:
   BlockExpr(BlockDecl *BD, QualType ty, bool ContainsUnexpandedParameterPack)
       : Expr(BlockExprClass, ty, VK_PRValue, OK_Ordinary), TheBlock(BD) {
     setDependence(computeDependence(this, ContainsUnexpandedParameterPack));
   }
 
   /// Build an empty block expression.
   explicit BlockExpr(EmptyShell Empty) : Expr(BlockExprClass, Empty) { }
 
   const BlockDecl *getBlockDecl() const { return TheBlock; }
   BlockDecl *getBlockDecl() { return TheBlock; }
   void setBlockDecl(BlockDecl *BD) { TheBlock = BD; }
 
   // Convenience functions for probing the underlying BlockDecl.
   SourceLocation getCaretLocation() const;
   const Stmt *getBody() const;
   Stmt *getBody();
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getCaretLocation();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getBody()->getEndLoc();
   }
 
   /// getFunctionType - Return the underlying function type for this block.
   const FunctionProtoType *getFunctionType() const;
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == BlockExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 };
 
 /// Copy initialization expr of a __block variable and a boolean flag that
 /// indicates whether the expression can throw.
 struct BlockVarCopyInit {
   BlockVarCopyInit() = default;
   BlockVarCopyInit(Expr *CopyExpr, bool CanThrow)
       : ExprAndFlag(CopyExpr, CanThrow) {}
   void setExprAndFlag(Expr *CopyExpr, bool CanThrow) {
     ExprAndFlag.setPointerAndInt(CopyExpr, CanThrow);
   }
   Expr *getCopyExpr() const { return ExprAndFlag.getPointer(); }
   bool canThrow() const { return ExprAndFlag.getInt(); }
   llvm::PointerIntPair<Expr *, 1, bool> ExprAndFlag;
 };
 
 /// AsTypeExpr - Clang builtin function __builtin_astype [OpenCL 6.2.4.2]
 /// This AST node provides support for reinterpreting a type to another
 /// type of the same size.
 class AsTypeExpr : public Expr {
 private:
   Stmt *SrcExpr;
   SourceLocation BuiltinLoc, RParenLoc;
 
   friend class ASTReader;
   friend class ASTStmtReader;
   explicit AsTypeExpr(EmptyShell Empty) : Expr(AsTypeExprClass, Empty) {}
 
 public:
   AsTypeExpr(Expr *SrcExpr, QualType DstType, ExprValueKind VK,
              ExprObjectKind OK, SourceLocation BuiltinLoc,
              SourceLocation RParenLoc)
       : Expr(AsTypeExprClass, DstType, VK, OK), SrcExpr(SrcExpr),
         BuiltinLoc(BuiltinLoc), RParenLoc(RParenLoc) {
     setDependence(computeDependence(this));
   }
 
   /// getSrcExpr - Return the Expr to be converted.
   Expr *getSrcExpr() const { return cast<Expr>(SrcExpr); }
 
   /// getBuiltinLoc - Return the location of the __builtin_astype token.
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
 
   /// getRParenLoc - Return the location of final right parenthesis.
   SourceLocation getRParenLoc() const { return RParenLoc; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == AsTypeExprClass;
   }
 
   // Iterators
   child_range children() { return child_range(&SrcExpr, &SrcExpr+1); }
   const_child_range children() const {
     return const_child_range(&SrcExpr, &SrcExpr + 1);
   }
 };
 
 /// PseudoObjectExpr - An expression which accesses a pseudo-object
 /// l-value.  A pseudo-object is an abstract object, accesses to which
 /// are translated to calls.  The pseudo-object expression has a
 /// syntactic form, which shows how the expression was actually
 /// written in the source code, and a semantic form, which is a series
 /// of expressions to be executed in order which detail how the
 /// operation is actually evaluated.  Optionally, one of the semantic
 /// forms may also provide a result value for the expression.
 ///
 /// If any of the semantic-form expressions is an OpaqueValueExpr,
 /// that OVE is required to have a source expression, and it is bound
 /// to the result of that source expression.  Such OVEs may appear
 /// only in subsequent semantic-form expressions and as
 /// sub-expressions of the syntactic form.
 ///
 /// PseudoObjectExpr should be used only when an operation can be
 /// usefully described in terms of fairly simple rewrite rules on
 /// objects and functions that are meant to be used by end-developers.
 /// For example, under the Itanium ABI, dynamic casts are implemented
 /// as a call to a runtime function called __dynamic_cast; using this
 /// class to describe that would be inappropriate because that call is
 /// not really part of the user-visible semantics, and instead the
 /// cast is properly reflected in the AST and IR-generation has been
 /// taught to generate the call as necessary.  In contrast, an
 /// Objective-C property access is semantically defined to be
 /// equivalent to a particular message send, and this is very much
 /// part of the user model.  The name of this class encourages this
 /// modelling design.
 class PseudoObjectExpr final
     : public Expr,
       private llvm::TrailingObjects<PseudoObjectExpr, Expr *> {
   // PseudoObjectExprBits.NumSubExprs - The number of sub-expressions.
   // Always at least two, because the first sub-expression is the
   // syntactic form.
 
   // PseudoObjectExprBits.ResultIndex - The index of the
   // sub-expression holding the result.  0 means the result is void,
   // which is unambiguous because it's the index of the syntactic
   // form.  Note that this is therefore 1 higher than the value passed
   // in to Create, which is an index within the semantic forms.
   // Note also that ASTStmtWriter assumes this encoding.
 
   Expr **getSubExprsBuffer() { return getTrailingObjects<Expr *>(); }
   const Expr * const *getSubExprsBuffer() const {
     return getTrailingObjects<Expr *>();
   }
 
   PseudoObjectExpr(QualType type, ExprValueKind VK,
                    Expr *syntactic, ArrayRef<Expr*> semantic,
                    unsigned resultIndex);
 
   PseudoObjectExpr(EmptyShell shell, unsigned numSemanticExprs);
 
   unsigned getNumSubExprs() const {
     return PseudoObjectExprBits.NumSubExprs;
   }
 
 public:
   /// NoResult - A value for the result index indicating that there is
   /// no semantic result.
   enum : unsigned { NoResult = ~0U };
 
   static PseudoObjectExpr *Create(const ASTContext &Context, Expr *syntactic,
                                   ArrayRef<Expr*> semantic,
                                   unsigned resultIndex);
 
   static PseudoObjectExpr *Create(const ASTContext &Context, EmptyShell shell,
                                   unsigned numSemanticExprs);
 
   /// Return the syntactic form of this expression, i.e. the
   /// expression it actually looks like.  Likely to be expressed in
   /// terms of OpaqueValueExprs bound in the semantic form.
   Expr *getSyntacticForm() { return getSubExprsBuffer()[0]; }
   const Expr *getSyntacticForm() const { return getSubExprsBuffer()[0]; }
 
   /// Return the index of the result-bearing expression into the semantics
   /// expressions, or PseudoObjectExpr::NoResult if there is none.
   unsigned getResultExprIndex() const {
     if (PseudoObjectExprBits.ResultIndex == 0) return NoResult;
     return PseudoObjectExprBits.ResultIndex - 1;
   }
 
   /// Return the result-bearing expression, or null if there is none.
   Expr *getResultExpr() {
     if (PseudoObjectExprBits.ResultIndex == 0)
       return nullptr;
     return getSubExprsBuffer()[PseudoObjectExprBits.ResultIndex];
   }
   const Expr *getResultExpr() const {
     return const_cast<PseudoObjectExpr*>(this)->getResultExpr();
   }
 
   unsigned getNumSemanticExprs() const { return getNumSubExprs() - 1; }
 
   typedef Expr * const *semantics_iterator;
   typedef const Expr * const *const_semantics_iterator;
   semantics_iterator semantics_begin() {
     return getSubExprsBuffer() + 1;
   }
   const_semantics_iterator semantics_begin() const {
     return getSubExprsBuffer() + 1;
   }
   semantics_iterator semantics_end() {
     return getSubExprsBuffer() + getNumSubExprs();
   }
   const_semantics_iterator semantics_end() const {
     return getSubExprsBuffer() + getNumSubExprs();
   }
 
   ArrayRef<Expr*> semantics() {
     return ArrayRef(semantics_begin(), semantics_end());
   }
   ArrayRef<const Expr*> semantics() const {
     return ArrayRef(semantics_begin(), semantics_end());
   }
 
   Expr *getSemanticExpr(unsigned index) {
     assert(index + 1 < getNumSubExprs());
     return getSubExprsBuffer()[index + 1];
   }
   const Expr *getSemanticExpr(unsigned index) const {
     return const_cast<PseudoObjectExpr*>(this)->getSemanticExpr(index);
   }
 
   SourceLocation getExprLoc() const LLVM_READONLY {
     return getSyntacticForm()->getExprLoc();
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getSyntacticForm()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY {
     return getSyntacticForm()->getEndLoc();
   }
 
   child_range children() {
     const_child_range CCR =
         const_cast<const PseudoObjectExpr *>(this)->children();
     return child_range(cast_away_const(CCR.begin()),
                        cast_away_const(CCR.end()));
   }
   const_child_range children() const {
     Stmt *const *cs = const_cast<Stmt *const *>(
         reinterpret_cast<const Stmt *const *>(getSubExprsBuffer()));
     return const_child_range(cs, cs + getNumSubExprs());
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == PseudoObjectExprClass;
   }
 
   friend TrailingObjects;
   friend class ASTStmtReader;
 };
 
 /// AtomicExpr - Variadic atomic builtins: __atomic_exchange, __atomic_fetch_*,
 /// __atomic_load, __atomic_store, and __atomic_compare_exchange_*, for the
 /// similarly-named C++11 instructions, and __c11 variants for <stdatomic.h>,
 /// and corresponding __opencl_atomic_* for OpenCL 2.0.
 /// All of these instructions take one primary pointer, at least one memory
 /// order. The instructions for which getScopeModel returns non-null value
 /// take one synch scope.
 class AtomicExpr : public Expr {
 public:
   enum AtomicOp {
 #define BUILTIN(ID, TYPE, ATTRS)
 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS) AO ## ID,
 #include "clang/Basic/Builtins.inc"
     // Avoid trailing comma
     BI_First = 0
   };
 
 private:
   /// Location of sub-expressions.
   /// The location of Scope sub-expression is NumSubExprs - 1, which is
   /// not fixed, therefore is not defined in enum.
   enum { PTR, ORDER, VAL1, ORDER_FAIL, VAL2, WEAK, END_EXPR };
   Stmt *SubExprs[END_EXPR + 1];
   unsigned NumSubExprs;
   SourceLocation BuiltinLoc, RParenLoc;
   AtomicOp Op;
 
   friend class ASTStmtReader;
 public:
   AtomicExpr(SourceLocation BLoc, ArrayRef<Expr*> args, QualType t,
              AtomicOp op, SourceLocation RP);
 
   /// Determine the number of arguments the specified atomic builtin
   /// should have.
   static unsigned getNumSubExprs(AtomicOp Op);
 
   /// Build an empty AtomicExpr.
   explicit AtomicExpr(EmptyShell Empty) : Expr(AtomicExprClass, Empty) { }
 
   Expr *getPtr() const {
     return cast<Expr>(SubExprs[PTR]);
   }
   Expr *getOrder() const {
     return cast<Expr>(SubExprs[ORDER]);
   }
   Expr *getScope() const {
     assert(getScopeModel() && "No scope");
     return cast<Expr>(SubExprs[NumSubExprs - 1]);
   }
   Expr *getVal1() const {
     if (Op == AO__c11_atomic_init || Op == AO__opencl_atomic_init)
       return cast<Expr>(SubExprs[ORDER]);
     assert(NumSubExprs > VAL1);
     return cast<Expr>(SubExprs[VAL1]);
   }
   Expr *getOrderFail() const {
     assert(NumSubExprs > ORDER_FAIL);
     return cast<Expr>(SubExprs[ORDER_FAIL]);
   }
   Expr *getVal2() const {
     if (Op == AO__atomic_exchange || Op == AO__scoped_atomic_exchange)
       return cast<Expr>(SubExprs[ORDER_FAIL]);
     assert(NumSubExprs > VAL2);
     return cast<Expr>(SubExprs[VAL2]);
   }
   Expr *getWeak() const {
     assert(NumSubExprs > WEAK);
     return cast<Expr>(SubExprs[WEAK]);
   }
   QualType getValueType() const;
 
   AtomicOp getOp() const { return Op; }
   StringRef getOpAsString() const {
     switch (Op) {
 #define BUILTIN(ID, TYPE, ATTRS)
 #define ATOMIC_BUILTIN(ID, TYPE, ATTRS)                                        \
   case AO##ID:                                                                 \
     return #ID;
 #include "clang/Basic/Builtins.inc"
     }
     llvm_unreachable("not an atomic operator?");
   }
   unsigned getNumSubExprs() const { return NumSubExprs; }
 
   Expr **getSubExprs() { return reinterpret_cast<Expr **>(SubExprs); }
   const Expr * const *getSubExprs() const {
     return reinterpret_cast<Expr * const *>(SubExprs);
   }
 
   bool isVolatile() const {
     return getPtr()->getType()->getPointeeType().isVolatileQualified();
   }
 
   bool isCmpXChg() const {
     return getOp() == AO__c11_atomic_compare_exchange_strong ||
            getOp() == AO__c11_atomic_compare_exchange_weak ||
            getOp() == AO__hip_atomic_compare_exchange_strong ||
            getOp() == AO__opencl_atomic_compare_exchange_strong ||
            getOp() == AO__opencl_atomic_compare_exchange_weak ||
            getOp() == AO__hip_atomic_compare_exchange_weak ||
            getOp() == AO__atomic_compare_exchange ||
            getOp() == AO__atomic_compare_exchange_n ||
            getOp() == AO__scoped_atomic_compare_exchange ||
            getOp() == AO__scoped_atomic_compare_exchange_n;
   }
 
   bool isOpenCL() const {
     return getOp() >= AO__opencl_atomic_compare_exchange_strong &&
            getOp() <= AO__opencl_atomic_store;
   }
 
   bool isHIP() const {
     return Op >= AO__hip_atomic_compare_exchange_strong &&
            Op <= AO__hip_atomic_store;
   }
 
   /// Return true if atomics operations targeting allocations in private memory
   /// are undefined.
   bool threadPrivateMemoryAtomicsAreUndefined() const {
     return isOpenCL() || isHIP();
   }
 
   SourceLocation getBuiltinLoc() const { return BuiltinLoc; }
   SourceLocation getRParenLoc() const { return RParenLoc; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return BuiltinLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return RParenLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == AtomicExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(SubExprs, SubExprs+NumSubExprs);
   }
   const_child_range children() const {
     return const_child_range(SubExprs, SubExprs + NumSubExprs);
   }
 
   /// Get atomic scope model for the atomic op code.
   /// \return empty atomic scope model if the atomic op code does not have
   ///   scope operand.
   static std::unique_ptr<AtomicScopeModel> getScopeModel(AtomicOp Op) {
     // FIXME: Allow grouping of builtins to be able to only check >= and <=
     if (Op >= AO__opencl_atomic_compare_exchange_strong &&
         Op <= AO__opencl_atomic_store && Op != AO__opencl_atomic_init)
       return AtomicScopeModel::create(AtomicScopeModelKind::OpenCL);
     if (Op >= AO__hip_atomic_compare_exchange_strong &&
         Op <= AO__hip_atomic_store)
       return AtomicScopeModel::create(AtomicScopeModelKind::HIP);
     if (Op >= AO__scoped_atomic_add_fetch && Op <= AO__scoped_atomic_xor_fetch)
       return AtomicScopeModel::create(AtomicScopeModelKind::Generic);
     return AtomicScopeModel::create(AtomicScopeModelKind::None);
   }
 
   /// Get atomic scope model.
   /// \return empty atomic scope model if this atomic expression does not have
   ///   scope operand.
   std::unique_ptr<AtomicScopeModel> getScopeModel() const {
     return getScopeModel(getOp());
   }
 };
 
 /// TypoExpr - Internal placeholder for expressions where typo correction
 /// still needs to be performed and/or an error diagnostic emitted.
 class TypoExpr : public Expr {
   // The location for the typo name.
   SourceLocation TypoLoc;
 
 public:
   TypoExpr(QualType T, SourceLocation TypoLoc)
       : Expr(TypoExprClass, T, VK_LValue, OK_Ordinary), TypoLoc(TypoLoc) {
     assert(T->isDependentType() && "TypoExpr given a non-dependent type");
     setDependence(ExprDependence::TypeValueInstantiation |
                   ExprDependence::Error);
   }
 
   child_range children() {
     return child_range(child_iterator(), child_iterator());
   }
   const_child_range children() const {
     return const_child_range(const_child_iterator(), const_child_iterator());
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY { return TypoLoc; }
   SourceLocation getEndLoc() const LLVM_READONLY { return TypoLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == TypoExprClass;
   }
 
 };
 
 /// This class represents BOTH the OpenMP Array Section and OpenACC 'subarray',
 /// with a boolean differentiator.
 /// OpenMP 5.0 [2.1.5, Array Sections].
 /// To specify an array section in an OpenMP construct, array subscript
 /// expressions are extended with the following syntax:
 /// \code
 /// [ lower-bound : length : stride ]
 /// [ lower-bound : length : ]
 /// [ lower-bound : length ]
 /// [ lower-bound : : stride ]
 /// [ lower-bound : : ]
 /// [ lower-bound : ]
 /// [ : length : stride ]
 /// [ : length : ]
 /// [ : length ]
 /// [ : : stride ]
 /// [ : : ]
 /// [ : ]
 /// \endcode
 /// The array section must be a subset of the original array.
 /// Array sections are allowed on multidimensional arrays. Base language array
 /// subscript expressions can be used to specify length-one dimensions of
 /// multidimensional array sections.
 /// Each of the lower-bound, length, and stride expressions if specified must be
 /// an integral type expressions of the base language. When evaluated
 /// they represent a set of integer values as follows:
 /// \code
 /// { lower-bound, lower-bound + stride, lower-bound + 2 * stride,... ,
 /// lower-bound + ((length - 1) * stride) }
 /// \endcode
 /// The lower-bound and length must evaluate to non-negative integers.
 /// The stride must evaluate to a positive integer.
 /// When the size of the array dimension is not known, the length must be
 /// specified explicitly.
 /// When the stride is absent it defaults to 1.
 /// When the length is absent it defaults to ⌈(size − lower-bound)/stride⌉,
 /// where size is the size of the array dimension. When the lower-bound is
 /// absent it defaults to 0.
 ///
 ///
 /// OpenACC 3.3 [2.7.1 Data Specification in Data Clauses]
 /// In C and C++, a subarray is an array name followed by an extended array
 /// range specification in brackets, with start and length, such as
 ///
 /// AA[2:n]
 ///
 /// If the lower bound is missing, zero is used. If the length is missing and
 /// the array has known size, the size of the array is used; otherwise the
 /// length is required. The subarray AA[2:n] means elements AA[2], AA[3], . . .
 /// , AA[2+n-1]. In C and C++, a two dimensional array may be declared in at
 /// least four ways:
 ///
 /// -Statically-sized array: float AA[100][200];
 /// -Pointer to statically sized rows: typedef float row[200]; row* BB;
 /// -Statically-sized array of pointers: float* CC[200];
 /// -Pointer to pointers: float** DD;
 ///
 /// Each dimension may be statically sized, or a pointer to dynamically
 /// allocated memory. Each of these may be included in a data clause using
 /// subarray notation to specify a rectangular array:
 ///
 /// -AA[2:n][0:200]
 /// -BB[2:n][0:m]
 /// -CC[2:n][0:m]
 /// -DD[2:n][0:m]
 ///
 /// Multidimensional rectangular subarrays in C and C++ may be specified for any
 /// array with any combination of statically-sized or dynamically-allocated
 /// dimensions. For statically sized dimensions, all dimensions except the first
 /// must specify the whole extent to preserve the contiguous data restriction,
 /// discussed below. For dynamically allocated dimensions, the implementation
 /// will allocate pointers in device memory corresponding to the pointers in
 /// local memory and will fill in those pointers as appropriate.
 ///
 /// In Fortran, a subarray is an array name followed by a comma-separated list
 /// of range specifications in parentheses, with lower and upper bound
 /// subscripts, such as
 ///
 /// arr(1:high,low:100)
 ///
 /// If either the lower or upper bounds are missing, the declared or allocated
 /// bounds of the array, if known, are used. All dimensions except the last must
 /// specify the whole extent, to preserve the contiguous data restriction,
 /// discussed below.
 ///
 /// Restrictions
 ///
 /// -In Fortran, the upper bound for the last dimension of an assumed-size dummy
 /// array must be specified.
 ///
 /// -In C and C++, the length for dynamically allocated dimensions of an array
 /// must be explicitly specified.
 ///
 /// -In C and C++, modifying pointers in pointer arrays during the data
 /// lifetime, either on the host or on the device, may result in undefined
 /// behavior.
 ///
 /// -If a subarray  appears in a data clause, the implementation may choose to
 /// allocate memory for only that subarray on the accelerator.
 ///
 /// -In Fortran, array pointers may appear, but pointer association is not
 /// preserved in device memory.
 ///
 /// -Any array or subarray in a data clause, including Fortran array pointers,
 /// must be a contiguous section of memory, except for dynamic multidimensional
 /// C arrays.
 ///
 /// -In C and C++, if a variable or array of composite type appears, all the
 /// data members of the struct or class are allocated and copied, as
 /// appropriate. If a composite member is a pointer type, the data addressed by
 /// that pointer are not implicitly copied.
 ///
 /// -In Fortran, if a variable or array of composite type appears, all the
 /// members of that derived type are allocated and copied, as appropriate. If
 /// any member has the allocatable or pointer attribute, the data accessed
 /// through that member are not copied.
 ///
 /// -If an expression is used in a subscript or subarray expression in a clause
 /// on a data construct, the same value is used when copying data at the end of
 /// the data region, even if the values of variables in the expression change
 /// during the data region.
 class ArraySectionExpr : public Expr {
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 
 public:
   enum ArraySectionType { OMPArraySection, OpenACCArraySection };
 
 private:
   enum {
     BASE,
     LOWER_BOUND,
     LENGTH,
     STRIDE,
     END_EXPR,
     OPENACC_END_EXPR = STRIDE
   };
 
   ArraySectionType ASType = OMPArraySection;
   Stmt *SubExprs[END_EXPR] = {nullptr};
   SourceLocation ColonLocFirst;
   SourceLocation ColonLocSecond;
   SourceLocation RBracketLoc;
 
 public:
   // Constructor for OMP array sections, which include a 'stride'.
   ArraySectionExpr(Expr *Base, Expr *LowerBound, Expr *Length, Expr *Stride,
                    QualType Type, ExprValueKind VK, ExprObjectKind OK,
                    SourceLocation ColonLocFirst, SourceLocation ColonLocSecond,
                    SourceLocation RBracketLoc)
       : Expr(ArraySectionExprClass, Type, VK, OK), ASType(OMPArraySection),
         ColonLocFirst(ColonLocFirst), ColonLocSecond(ColonLocSecond),
         RBracketLoc(RBracketLoc) {
     setBase(Base);
     setLowerBound(LowerBound);
     setLength(Length);
     setStride(Stride);
     setDependence(computeDependence(this));
   }
 
   // Constructor for OpenACC sub-arrays, which do not permit a 'stride'.
   ArraySectionExpr(Expr *Base, Expr *LowerBound, Expr *Length, QualType Type,
                    ExprValueKind VK, ExprObjectKind OK, SourceLocation ColonLoc,
                    SourceLocation RBracketLoc)
       : Expr(ArraySectionExprClass, Type, VK, OK), ASType(OpenACCArraySection),
         ColonLocFirst(ColonLoc), RBracketLoc(RBracketLoc) {
     setBase(Base);
     setLowerBound(LowerBound);
     setLength(Length);
     setDependence(computeDependence(this));
   }
 
   /// Create an empty array section expression.
   explicit ArraySectionExpr(EmptyShell Shell)
       : Expr(ArraySectionExprClass, Shell) {}
 
   /// Return original type of the base expression for array section.
   static QualType getBaseOriginalType(const Expr *Base);
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == ArraySectionExprClass;
   }
 
   bool isOMPArraySection() const { return ASType == OMPArraySection; }
   bool isOpenACCArraySection() const { return ASType == OpenACCArraySection; }
 
   /// Get base of the array section.
   Expr *getBase() { return cast<Expr>(SubExprs[BASE]); }
   const Expr *getBase() const { return cast<Expr>(SubExprs[BASE]); }
 
   /// Get lower bound of array section.
   Expr *getLowerBound() { return cast_or_null<Expr>(SubExprs[LOWER_BOUND]); }
   const Expr *getLowerBound() const {
     return cast_or_null<Expr>(SubExprs[LOWER_BOUND]);
   }
 
   /// Get length of array section.
   Expr *getLength() { return cast_or_null<Expr>(SubExprs[LENGTH]); }
   const Expr *getLength() const { return cast_or_null<Expr>(SubExprs[LENGTH]); }
 
   /// Get stride of array section.
   Expr *getStride() {
     assert(ASType != OpenACCArraySection &&
            "Stride not valid in OpenACC subarrays");
     return cast_or_null<Expr>(SubExprs[STRIDE]);
   }
 
   const Expr *getStride() const {
     assert(ASType != OpenACCArraySection &&
            "Stride not valid in OpenACC subarrays");
     return cast_or_null<Expr>(SubExprs[STRIDE]);
   }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return getBase()->getBeginLoc();
   }
   SourceLocation getEndLoc() const LLVM_READONLY { return RBracketLoc; }
 
   SourceLocation getColonLocFirst() const { return ColonLocFirst; }
   SourceLocation getColonLocSecond() const {
     assert(ASType != OpenACCArraySection &&
            "second colon for stride not valid in OpenACC subarrays");
     return ColonLocSecond;
   }
   SourceLocation getRBracketLoc() const { return RBracketLoc; }
 
   SourceLocation getExprLoc() const LLVM_READONLY {
     return getBase()->getExprLoc();
   }
 
   child_range children() {
     return child_range(
         &SubExprs[BASE],
         &SubExprs[ASType == OMPArraySection ? END_EXPR : OPENACC_END_EXPR]);
   }
 
   const_child_range children() const {
     return const_child_range(
         &SubExprs[BASE],
         &SubExprs[ASType == OMPArraySection ? END_EXPR : OPENACC_END_EXPR]);
   }
 
 private:
   /// Set base of the array section.
   void setBase(Expr *E) { SubExprs[BASE] = E; }
 
   /// Set lower bound of the array section.
   void setLowerBound(Expr *E) { SubExprs[LOWER_BOUND] = E; }
 
   /// Set length of the array section.
   void setLength(Expr *E) { SubExprs[LENGTH] = E; }
 
   /// Set length of the array section.
   void setStride(Expr *E) {
     assert(ASType != OpenACCArraySection &&
            "Stride not valid in OpenACC subarrays");
     SubExprs[STRIDE] = E;
   }
 
   void setColonLocFirst(SourceLocation L) { ColonLocFirst = L; }
 
   void setColonLocSecond(SourceLocation L) {
     assert(ASType != OpenACCArraySection &&
            "second colon for stride not valid in OpenACC subarrays");
     ColonLocSecond = L;
   }
   void setRBracketLoc(SourceLocation L) { RBracketLoc = L; }
 };
 
 /// This class represents temporary values used to represent inout and out
 /// arguments in HLSL. From the callee perspective these parameters are more or
 /// less __restrict__ T&. They are guaranteed to not alias any memory. inout
 /// parameters are initialized by the caller, and out parameters are references
 /// to uninitialized memory.
 ///
 /// In the caller, the argument expression creates a temporary in local memory
 /// and the address of the temporary is passed into the callee. There may be
 /// implicit conversion sequences to initialize the temporary, and on expiration
 /// of the temporary an inverse conversion sequence is applied as a write-back
 /// conversion to the source l-value.
 ///
 /// This AST node has three sub-expressions:
 ///  - An OpaqueValueExpr with a source that is the argument lvalue expression.
 ///  - An OpaqueValueExpr with a source that is an implicit conversion
 ///    sequence from the source lvalue to the argument type.
 ///  - An expression that assigns the second expression into the first,
 ///    performing any necessary conversions.
 class HLSLOutArgExpr : public Expr {
   friend class ASTStmtReader;
 
   enum {
     BaseLValue,
     CastedTemporary,
     WritebackCast,
     NumSubExprs,
   };
 
   Stmt *SubExprs[NumSubExprs];
   bool IsInOut;
 
   HLSLOutArgExpr(QualType Ty, OpaqueValueExpr *B, OpaqueValueExpr *OpV,
                  Expr *WB, bool IsInOut)
       : Expr(HLSLOutArgExprClass, Ty, VK_LValue, OK_Ordinary),
         IsInOut(IsInOut) {
     SubExprs[BaseLValue] = B;
     SubExprs[CastedTemporary] = OpV;
     SubExprs[WritebackCast] = WB;
     assert(!Ty->isDependentType() && "HLSLOutArgExpr given a dependent type!");
   }
 
   explicit HLSLOutArgExpr(EmptyShell Shell)
       : Expr(HLSLOutArgExprClass, Shell) {}
 
 public:
   static HLSLOutArgExpr *Create(const ASTContext &C, QualType Ty,
                                 OpaqueValueExpr *Base, OpaqueValueExpr *OpV,
                                 Expr *WB, bool IsInOut);
   static HLSLOutArgExpr *CreateEmpty(const ASTContext &Ctx);
 
   const OpaqueValueExpr *getOpaqueArgLValue() const {
     return cast<OpaqueValueExpr>(SubExprs[BaseLValue]);
   }
   OpaqueValueExpr *getOpaqueArgLValue() {
     return cast<OpaqueValueExpr>(SubExprs[BaseLValue]);
   }
 
   /// Return the l-value expression that was written as the argument
   /// in source.  Everything else here is implicitly generated.
   const Expr *getArgLValue() const {
     return getOpaqueArgLValue()->getSourceExpr();
   }
   Expr *getArgLValue() { return getOpaqueArgLValue()->getSourceExpr(); }
 
   const Expr *getWritebackCast() const {
     return cast<Expr>(SubExprs[WritebackCast]);
   }
   Expr *getWritebackCast() { return cast<Expr>(SubExprs[WritebackCast]); }
 
   const OpaqueValueExpr *getCastedTemporary() const {
     return cast<OpaqueValueExpr>(SubExprs[CastedTemporary]);
   }
   OpaqueValueExpr *getCastedTemporary() {
     return cast<OpaqueValueExpr>(SubExprs[CastedTemporary]);
   }
 
   /// returns true if the parameter is inout and false if the parameter is out.
   bool isInOut() const { return IsInOut; }
 
   SourceLocation getBeginLoc() const LLVM_READONLY {
     return SubExprs[BaseLValue]->getBeginLoc();
   }
 
   SourceLocation getEndLoc() const LLVM_READONLY {
     return SubExprs[BaseLValue]->getEndLoc();
   }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == HLSLOutArgExprClass;
   }
 
   // Iterators
   child_range children() {
     return child_range(&SubExprs[BaseLValue], &SubExprs[NumSubExprs]);
   }
 };
 
 /// Frontend produces RecoveryExprs on semantic errors that prevent creating
 /// other well-formed expressions. E.g. when type-checking of a binary operator
 /// fails, we cannot produce a BinaryOperator expression. Instead, we can choose
 /// to produce a recovery expression storing left and right operands.
 ///
 /// RecoveryExpr does not have any semantic meaning in C++, it is only useful to
 /// preserve expressions in AST that would otherwise be dropped. It captures
 /// subexpressions of some expression that we could not construct and source
 /// range covered by the expression.
 ///
 /// By default, RecoveryExpr uses dependence-bits to take advantage of existing
 /// machinery to deal with dependent code in C++, e.g. RecoveryExpr is preserved
 /// in `decltype(<broken-expr>)` as part of the `DependentDecltypeType`. In
 /// addition to that, clang does not report most errors on dependent
 /// expressions, so we get rid of bogus errors for free. However, note that
 /// unlike other dependent expressions, RecoveryExpr can be produced in
 /// non-template contexts.
 ///
 /// We will preserve the type in RecoveryExpr when the type is known, e.g.
 /// preserving the return type for a broken non-overloaded function call, a
 /// overloaded call where all candidates have the same return type. In this
 /// case, the expression is not type-dependent (unless the known type is itself
 /// dependent)
 ///
 /// One can also reliably suppress all bogus errors on expressions containing
 /// recovery expressions by examining results of Expr::containsErrors().
 class RecoveryExpr final : public Expr,
                            private llvm::TrailingObjects<RecoveryExpr, Expr *> {
 public:
   static RecoveryExpr *Create(ASTContext &Ctx, QualType T,
                               SourceLocation BeginLoc, SourceLocation EndLoc,
                               ArrayRef<Expr *> SubExprs);
   static RecoveryExpr *CreateEmpty(ASTContext &Ctx, unsigned NumSubExprs);
 
   ArrayRef<Expr *> subExpressions() {
     auto *B = getTrailingObjects<Expr *>();
     return llvm::ArrayRef(B, B + NumExprs);
   }
 
   ArrayRef<const Expr *> subExpressions() const {
     return const_cast<RecoveryExpr *>(this)->subExpressions();
   }
 
   child_range children() {
     Stmt **B = reinterpret_cast<Stmt **>(getTrailingObjects<Expr *>());
     return child_range(B, B + NumExprs);
   }
 
   SourceLocation getBeginLoc() const { return BeginLoc; }
   SourceLocation getEndLoc() const { return EndLoc; }
 
   static bool classof(const Stmt *T) {
     return T->getStmtClass() == RecoveryExprClass;
   }
 
 private:
   RecoveryExpr(ASTContext &Ctx, QualType T, SourceLocation BeginLoc,
                SourceLocation EndLoc, ArrayRef<Expr *> SubExprs);
   RecoveryExpr(EmptyShell Empty, unsigned NumSubExprs)
       : Expr(RecoveryExprClass, Empty), NumExprs(NumSubExprs) {}
 
   size_t numTrailingObjects(OverloadToken<Stmt *>) const { return NumExprs; }
 
   SourceLocation BeginLoc, EndLoc;
   unsigned NumExprs;
   friend TrailingObjects;
   friend class ASTStmtReader;
   friend class ASTStmtWriter;
 };
 
 } // end namespace clang
 
 #endif // LLVM_CLANG_AST_EXPR_H