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//===- NestedNameSpecifier.h - C++ nested name specifiers -------*- 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 NestedNameSpecifier class, which represents

//  a C++ nested-name-specifier.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H

#define LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H

#include "clang/AST/DependenceFlags.h"

#include "clang/Basic/Diagnostic.h"

#include "clang/Basic/SourceLocation.h"

#include "llvm/ADT/DenseMapInfo.h"

#include "llvm/ADT/FoldingSet.h"

#include "llvm/ADT/PointerIntPair.h"

#include "llvm/Support/Compiler.h"

#include <cstdint>

#include <cstdlib>

#include <utility>

namespace clang {

class ASTContext;

class CXXRecordDecl;

class IdentifierInfo;

class LangOptions;

class NamespaceAliasDecl;

class NamespaceDecl;

struct PrintingPolicy;

class Type;

class TypeLoc;

/// Represents a C++ nested name specifier, such as

/// "\::std::vector<int>::".

///

/// C++ nested name specifiers are the prefixes to qualified

/// names. For example, "foo::" in "foo::x" is a nested name

/// specifier. Nested name specifiers are made up of a sequence of

/// specifiers, each of which can be a namespace, type, identifier

/// (for dependent names), decltype specifier, or the global specifier ('::').

/// The last two specifiers can only appear at the start of a

/// nested-namespace-specifier.

class NestedNameSpecifier : public llvm::FoldingSetNode {

  /// Enumeration describing

  enum StoredSpecifierKind {

    StoredIdentifier = 0,

    StoredDecl = 1,

    StoredTypeSpec = 2,

    StoredTypeSpecWithTemplate = 3

  };

  /// The nested name specifier that precedes this nested name

  /// specifier.

  ///

  /// The pointer is the nested-name-specifier that precedes this

  /// one. The integer stores one of the first four values of type

  /// SpecifierKind.

  llvm::PointerIntPair<NestedNameSpecifier *, 2, StoredSpecifierKind> Prefix;

  /// The last component in the nested name specifier, which

  /// can be an identifier, a declaration, or a type.

  ///

  /// When the pointer is NULL, this specifier represents the global

  /// specifier '::'. Otherwise, the pointer is one of

  /// IdentifierInfo*, Namespace*, or Type*, depending on the kind of

  /// specifier as encoded within the prefix.

  void* Specifier = nullptr;

public:

  /// The kind of specifier that completes this nested name

  /// specifier.

  enum SpecifierKind {

    /// An identifier, stored as an IdentifierInfo*.

    Identifier,

    /// A namespace, stored as a NamespaceDecl*.

    Namespace,

    /// A namespace alias, stored as a NamespaceAliasDecl*.

    NamespaceAlias,

    /// A type, stored as a Type*.

    TypeSpec,

    /// A type that was preceded by the 'template' keyword,

    /// stored as a Type*.

    TypeSpecWithTemplate,

    /// The global specifier '::'. There is no stored value.

    Global,

    /// Microsoft's '__super' specifier, stored as a CXXRecordDecl* of

    /// the class it appeared in.

    Super

  };

private:

  /// Builds the global specifier.

  NestedNameSpecifier() : Prefix(nullptr, StoredIdentifier) {}

  /// Copy constructor used internally to clone nested name

  /// specifiers.

  NestedNameSpecifier(const NestedNameSpecifier &Other) = default;

  /// Either find or insert the given nested name specifier

  /// mockup in the given context.

  static NestedNameSpecifier *FindOrInsert(const ASTContext &Context,

                                           const NestedNameSpecifier &Mockup);

public:

  NestedNameSpecifier &operator=(const NestedNameSpecifier &) = delete;

  /// Builds a specifier combining a prefix and an identifier.

  ///

  /// The prefix must be dependent, since nested name specifiers

  /// referencing an identifier are only permitted when the identifier

  /// cannot be resolved.

  static NestedNameSpecifier *Create(const ASTContext &Context,

                                     NestedNameSpecifier *Prefix,

                                     IdentifierInfo *II);

  /// Builds a nested name specifier that names a namespace.

  static NestedNameSpecifier *Create(const ASTContext &Context,

                                     NestedNameSpecifier *Prefix,

                                     const NamespaceDecl *NS);

  /// Builds a nested name specifier that names a namespace alias.

  static NestedNameSpecifier *Create(const ASTContext &Context,

                                     NestedNameSpecifier *Prefix,

                                     NamespaceAliasDecl *Alias);

  /// Builds a nested name specifier that names a type.

  static NestedNameSpecifier *Create(const ASTContext &Context,

                                     NestedNameSpecifier *Prefix,

                                     bool Template, const Type *T);

  /// Builds a specifier that consists of just an identifier.

  ///

  /// The nested-name-specifier is assumed to be dependent, but has no

  /// prefix because the prefix is implied by something outside of the

  /// nested name specifier, e.g., in "x->Base::f", the "x" has a dependent

  /// type.

  static NestedNameSpecifier *Create(const ASTContext &Context,

                                     IdentifierInfo *II);

  /// Returns the nested name specifier representing the global

  /// scope.

  static NestedNameSpecifier *GlobalSpecifier(const ASTContext &Context);

  /// Returns the nested name specifier representing the __super scope

  /// for the given CXXRecordDecl.

  static NestedNameSpecifier *SuperSpecifier(const ASTContext &Context,

                                             CXXRecordDecl *RD);

  /// Return the prefix of this nested name specifier.

  ///

  /// The prefix contains all of the parts of the nested name

  /// specifier that precede this current specifier. For example, for a

  /// nested name specifier that represents "foo::bar::", the current

  /// specifier will contain "bar::" and the prefix will contain

  /// "foo::".

  NestedNameSpecifier *getPrefix() const { return Prefix.getPointer(); }

  /// Determine what kind of nested name specifier is stored.

  SpecifierKind getKind() const;

  /// Retrieve the identifier stored in this nested name

  /// specifier.

  IdentifierInfo *getAsIdentifier() const {

    if (Prefix.getInt() == StoredIdentifier)

      return (IdentifierInfo *)Specifier;

    return nullptr;

  }

  /// Retrieve the namespace stored in this nested name

  /// specifier.

  NamespaceDecl *getAsNamespace() const;

  /// Retrieve the namespace alias stored in this nested name

  /// specifier.

  NamespaceAliasDecl *getAsNamespaceAlias() const;

  /// Retrieve the record declaration stored in this nested name

  /// specifier.

  CXXRecordDecl *getAsRecordDecl() const;

  /// Retrieve the type stored in this nested name specifier.

  const Type *getAsType() const {

    if (Prefix.getInt() == StoredTypeSpec ||

        Prefix.getInt() == StoredTypeSpecWithTemplate)

      return (const Type *)Specifier;

    return nullptr;

  }

  NestedNameSpecifierDependence getDependence() const;

  /// Whether this nested name specifier refers to a dependent

  /// type or not.

  bool isDependent() const;

  /// Whether this nested name specifier involves a template

  /// parameter.

  bool isInstantiationDependent() const;

  /// Whether this nested-name-specifier contains an unexpanded

  /// parameter pack (for C++11 variadic templates).

  bool containsUnexpandedParameterPack() const;

  /// Whether this nested name specifier contains an error.

  bool containsErrors() const;

  /// Print this nested name specifier to the given output stream. If

  /// `ResolveTemplateArguments` is true, we'll print actual types, e.g.

  /// `ns::SomeTemplate<int, MyClass>` instead of

  /// `ns::SomeTemplate<Container::value_type, T>`.

  void print(raw_ostream &OS, const PrintingPolicy &Policy,

             bool ResolveTemplateArguments = false) const;

  void Profile(llvm::FoldingSetNodeID &ID) const {

    ID.AddPointer(Prefix.getOpaqueValue());

    ID.AddPointer(Specifier);

  }

  /// Dump the nested name specifier to standard output to aid

  /// in debugging.

  void dump(const LangOptions &LO) const;

  void dump() const;

  void dump(llvm::raw_ostream &OS) const;

  void dump(llvm::raw_ostream &OS, const LangOptions &LO) const;

};

/// A C++ nested-name-specifier augmented with source location

/// information.

class NestedNameSpecifierLoc {

  NestedNameSpecifier *Qualifier = nullptr;

  void *Data = nullptr;

  /// Determines the data length for the last component in the

  /// given nested-name-specifier.

  static unsigned getLocalDataLength(NestedNameSpecifier *Qualifier);

  /// Determines the data length for the entire

  /// nested-name-specifier.

  static unsigned getDataLength(NestedNameSpecifier *Qualifier);

public:

  /// Construct an empty nested-name-specifier.

  NestedNameSpecifierLoc() = default;

  /// Construct a nested-name-specifier with source location information

  /// from

  NestedNameSpecifierLoc(NestedNameSpecifier *Qualifier, void *Data)

      : Qualifier(Qualifier), Data(Data) {}

  /// Evaluates true when this nested-name-specifier location is

  /// non-empty.

  explicit operator bool() const { return Qualifier; }

  /// Evaluates true when this nested-name-specifier location is

  /// empty.

  bool hasQualifier() const { return Qualifier; }

  /// Retrieve the nested-name-specifier to which this instance

  /// refers.

  NestedNameSpecifier *getNestedNameSpecifier() const {

    return Qualifier;

  }

  /// Retrieve the opaque pointer that refers to source-location data.

  void *getOpaqueData() const { return Data; }

  /// Retrieve the source range covering the entirety of this

  /// nested-name-specifier.

  ///

  /// For example, if this instance refers to a nested-name-specifier

  /// \c \::std::vector<int>::, the returned source range would cover

  /// from the initial '::' to the last '::'.

  SourceRange getSourceRange() const LLVM_READONLY;

  /// Retrieve the source range covering just the last part of

  /// this nested-name-specifier, not including the prefix.

  ///

  /// For example, if this instance refers to a nested-name-specifier

  /// \c \::std::vector<int>::, the returned source range would cover

  /// from "vector" to the last '::'.

  SourceRange getLocalSourceRange() const;

  /// Retrieve the location of the beginning of this

  /// nested-name-specifier.

  SourceLocation getBeginLoc() const {

    return getSourceRange().getBegin();

  }

  /// Retrieve the location of the end of this

  /// nested-name-specifier.

  SourceLocation getEndLoc() const {

    return getSourceRange().getEnd();

  }

  /// Retrieve the location of the beginning of this

  /// component of the nested-name-specifier.

  SourceLocation getLocalBeginLoc() const {

    return getLocalSourceRange().getBegin();

  }

  /// Retrieve the location of the end of this component of the

  /// nested-name-specifier.

  SourceLocation getLocalEndLoc() const {

    return getLocalSourceRange().getEnd();

  }

  /// Return the prefix of this nested-name-specifier.

  ///

  /// For example, if this instance refers to a nested-name-specifier

  /// \c \::std::vector<int>::, the prefix is \c \::std::. Note that the

  /// returned prefix may be empty, if this is the first component of

  /// the nested-name-specifier.

  NestedNameSpecifierLoc getPrefix() const {

    if (!Qualifier)

      return *this;

    return NestedNameSpecifierLoc(Qualifier->getPrefix(), Data);

  }

  /// For a nested-name-specifier that refers to a type,

  /// retrieve the type with source-location information.

  TypeLoc getTypeLoc() const;

  /// Determines the data length for the entire

  /// nested-name-specifier.

  unsigned getDataLength() const { return getDataLength(Qualifier); }

  friend bool operator==(NestedNameSpecifierLoc X,

                         NestedNameSpecifierLoc Y) {

    return X.Qualifier == Y.Qualifier && X.Data == Y.Data;

  }

  friend bool operator!=(NestedNameSpecifierLoc X,

                         NestedNameSpecifierLoc Y) {

    return !(X == Y);

  }

};

/// Class that aids in the construction of nested-name-specifiers along

/// with source-location information for all of the components of the

/// nested-name-specifier.

class NestedNameSpecifierLocBuilder {

  /// The current representation of the nested-name-specifier we're

  /// building.

  NestedNameSpecifier *Representation = nullptr;

  /// Buffer used to store source-location information for the

  /// nested-name-specifier.

  ///

  /// Note that we explicitly manage the buffer (rather than using a

  /// SmallVector) because \c Declarator expects it to be possible to memcpy()

  /// a \c CXXScopeSpec, and CXXScopeSpec uses a NestedNameSpecifierLocBuilder.

  char *Buffer = nullptr;

  /// The size of the buffer used to store source-location information

  /// for the nested-name-specifier.

  unsigned BufferSize = 0;

  /// The capacity of the buffer used to store source-location

  /// information for the nested-name-specifier.

  unsigned BufferCapacity = 0;

public:

  NestedNameSpecifierLocBuilder() = default;

  NestedNameSpecifierLocBuilder(const NestedNameSpecifierLocBuilder &Other);

  NestedNameSpecifierLocBuilder &

  operator=(const NestedNameSpecifierLocBuilder &Other);

  ~NestedNameSpecifierLocBuilder() {

    if (BufferCapacity)

      free(Buffer);

  }

  /// Retrieve the representation of the nested-name-specifier.

  NestedNameSpecifier *getRepresentation() const { return Representation; }

  /// Extend the current nested-name-specifier by another

  /// nested-name-specifier component of the form 'type::'.

  ///

  /// \param Context The AST context in which this nested-name-specifier

  /// resides.

  ///

  /// \param TemplateKWLoc The location of the 'template' keyword, if present.

  ///

  /// \param TL The TypeLoc that describes the type preceding the '::'.

  ///

  /// \param ColonColonLoc The location of the trailing '::'.

  void Extend(ASTContext &Context, SourceLocation TemplateKWLoc, TypeLoc TL,

              SourceLocation ColonColonLoc);

  /// Extend the current nested-name-specifier by another

  /// nested-name-specifier component of the form 'identifier::'.

  ///

  /// \param Context The AST context in which this nested-name-specifier

  /// resides.

  ///

  /// \param Identifier The identifier.

  ///

  /// \param IdentifierLoc The location of the identifier.

  ///

  /// \param ColonColonLoc The location of the trailing '::'.

  void Extend(ASTContext &Context, IdentifierInfo *Identifier,

              SourceLocation IdentifierLoc, SourceLocation ColonColonLoc);

  /// Extend the current nested-name-specifier by another

  /// nested-name-specifier component of the form 'namespace::'.

  ///

  /// \param Context The AST context in which this nested-name-specifier

  /// resides.

  ///

  /// \param Namespace The namespace.

  ///

  /// \param NamespaceLoc The location of the namespace name.

  ///

  /// \param ColonColonLoc The location of the trailing '::'.

  void Extend(ASTContext &Context, NamespaceDecl *Namespace,

              SourceLocation NamespaceLoc, SourceLocation ColonColonLoc);

  /// Extend the current nested-name-specifier by another

  /// nested-name-specifier component of the form 'namespace-alias::'.

  ///

  /// \param Context The AST context in which this nested-name-specifier

  /// resides.

  ///

  /// \param Alias The namespace alias.

  ///

  /// \param AliasLoc The location of the namespace alias

  /// name.

  ///

  /// \param ColonColonLoc The location of the trailing '::'.

  void Extend(ASTContext &Context, NamespaceAliasDecl *Alias,

              SourceLocation AliasLoc, SourceLocation ColonColonLoc);

  /// Turn this (empty) nested-name-specifier into the global

  /// nested-name-specifier '::'.

  void MakeGlobal(ASTContext &Context, SourceLocation ColonColonLoc);

  /// Turns this (empty) nested-name-specifier into '__super'

  /// nested-name-specifier.

  ///

  /// \param Context The AST context in which this nested-name-specifier

  /// resides.

  ///

  /// \param RD The declaration of the class in which nested-name-specifier

  /// appeared.

  ///

  /// \param SuperLoc The location of the '__super' keyword.

  /// name.

  ///

  /// \param ColonColonLoc The location of the trailing '::'.

  void MakeSuper(ASTContext &Context, CXXRecordDecl *RD,

                 SourceLocation SuperLoc, SourceLocation ColonColonLoc);

  /// Make a new nested-name-specifier from incomplete source-location

  /// information.

  ///

  /// This routine should be used very, very rarely, in cases where we

  /// need to synthesize a nested-name-specifier. Most code should instead use

  /// \c Adopt() with a proper \c NestedNameSpecifierLoc.

  void MakeTrivial(ASTContext &Context, NestedNameSpecifier *Qualifier,

                   SourceRange R);

  /// Adopt an existing nested-name-specifier (with source-range

  /// information).

  void Adopt(NestedNameSpecifierLoc Other);

  /// Retrieve the source range covered by this nested-name-specifier.

  SourceRange getSourceRange() const LLVM_READONLY {

    return NestedNameSpecifierLoc(Representation, Buffer).getSourceRange();

  }

  /// Retrieve a nested-name-specifier with location information,

  /// copied into the given AST context.

  ///

  /// \param Context The context into which this nested-name-specifier will be

  /// copied.

  NestedNameSpecifierLoc getWithLocInContext(ASTContext &Context) const;

  /// Retrieve a nested-name-specifier with location

  /// information based on the information in this builder.

  ///

  /// This loc will contain references to the builder's internal data and may

  /// be invalidated by any change to the builder.

  NestedNameSpecifierLoc getTemporary() const {

    return NestedNameSpecifierLoc(Representation, Buffer);

  }

  /// Clear out this builder, and prepare it to build another

  /// nested-name-specifier with source-location information.

  void Clear() {

    Representation = nullptr;

    BufferSize = 0;

  }

  /// Retrieve the underlying buffer.

  ///

  /// \returns A pair containing a pointer to the buffer of source-location

  /// data and the size of the source-location data that resides in that

  /// buffer.

  std::pair<char *, unsigned> getBuffer() const {

    return std::make_pair(Buffer, BufferSize);

  }

};

/// Insertion operator for diagnostics.  This allows sending

/// NestedNameSpecifiers into a diagnostic with <<.

inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,

                                             NestedNameSpecifier *NNS) {

  DB.AddTaggedVal(reinterpret_cast<uint64_t>(NNS),

                  DiagnosticsEngine::ak_nestednamespec);

  return DB;

}

} // namespace clang

namespace llvm {

template <> struct DenseMapInfo<clang::NestedNameSpecifierLoc> {

  using FirstInfo = DenseMapInfo<clang::NestedNameSpecifier *>;

  using SecondInfo = DenseMapInfo<void *>;

  static clang::NestedNameSpecifierLoc getEmptyKey() {

    return clang::NestedNameSpecifierLoc(FirstInfo::getEmptyKey(),

                                         SecondInfo::getEmptyKey());

  }

  static clang::NestedNameSpecifierLoc getTombstoneKey() {

    return clang::NestedNameSpecifierLoc(FirstInfo::getTombstoneKey(),

                                         SecondInfo::getTombstoneKey());

  }

  static unsigned getHashValue(const clang::NestedNameSpecifierLoc &PairVal) {

    return hash_combine(

        FirstInfo::getHashValue(PairVal.getNestedNameSpecifier()),

        SecondInfo::getHashValue(PairVal.getOpaqueData()));

  }

  static bool isEqual(const clang::NestedNameSpecifierLoc &LHS,

                      const clang::NestedNameSpecifierLoc &RHS) {

    return LHS == RHS;

  }

};

} // namespace llvm

#endif // LLVM_CLANG_AST_NESTEDNAMESPECIFIER_H