llvm/clang/include/clang/AST/DeclCXX.h

//===- DeclCXX.h - Classes for representing C++ declarations --*- 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
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Defines the C++ Decl subclasses, other than those for templates
/// (found in DeclTemplate.h) and friends (in DeclFriend.h).
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_DECLCXX_H
#define LLVM_CLANG_AST_DECLCXX_H

#include "clang/AST/ASTUnresolvedSet.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/Expr.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/LambdaCapture.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/Redeclarable.h"
#include "clang/AST/Stmt.h"
#include "clang/AST/Type.h"
#include "clang/AST/TypeLoc.h"
#include "clang/AST/UnresolvedSet.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/Lambda.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/PointerLikeTypeTraits.h"
#include "llvm/Support/TrailingObjects.h"
#include <cassert>
#include <cstddef>
#include <iterator>
#include <memory>
#include <vector>

namespace clang {

class ASTContext;
class ClassTemplateDecl;
class ConstructorUsingShadowDecl;
class CXXBasePath;
class CXXBasePaths;
class CXXConstructorDecl;
class CXXDestructorDecl;
class CXXFinalOverriderMap;
class CXXIndirectPrimaryBaseSet;
class CXXMethodDecl;
class DecompositionDecl;
class FriendDecl;
class FunctionTemplateDecl;
class IdentifierInfo;
class MemberSpecializationInfo;
class BaseUsingDecl;
class TemplateDecl;
class TemplateParameterList;
class UsingDecl;

/// Represents an access specifier followed by colon ':'.
///
/// An objects of this class represents sugar for the syntactic occurrence
/// of an access specifier followed by a colon in the list of member
/// specifiers of a C++ class definition.
///
/// Note that they do not represent other uses of access specifiers,
/// such as those occurring in a list of base specifiers.
/// Also note that this class has nothing to do with so-called
/// "access declarations" (C++98 11.3 [class.access.dcl]).
class AccessSpecDecl : public Decl { … };

/// Represents a base class of a C++ class.
///
/// Each CXXBaseSpecifier represents a single, direct base class (or
/// struct) of a C++ class (or struct). It specifies the type of that
/// base class, whether it is a virtual or non-virtual base, and what
/// level of access (public, protected, private) is used for the
/// derivation. For example:
///
/// \code
///   class A { };
///   class B { };
///   class C : public virtual A, protected B { };
/// \endcode
///
/// In this code, C will have two CXXBaseSpecifiers, one for "public
/// virtual A" and the other for "protected B".
class CXXBaseSpecifier { … };

/// Represents a C++ struct/union/class.
class CXXRecordDecl : public RecordDecl { … };

/// Store information needed for an explicit specifier.
/// Used by CXXDeductionGuideDecl, CXXConstructorDecl and CXXConversionDecl.
class ExplicitSpecifier { … };

/// Represents a C++ deduction guide declaration.
///
/// \code
/// template<typename T> struct A { A(); A(T); };
/// A() -> A<int>;
/// \endcode
///
/// In this example, there will be an explicit deduction guide from the
/// second line, and implicit deduction guide templates synthesized from
/// the constructors of \c A.
class CXXDeductionGuideDecl : public FunctionDecl { … };

/// \brief Represents the body of a requires-expression.
///
/// This decl exists merely to serve as the DeclContext for the local
/// parameters of the requires expression as well as other declarations inside
/// it.
///
/// \code
/// template<typename T> requires requires (T t) { {t++} -> regular; }
/// \endcode
///
/// In this example, a RequiresExpr object will be generated for the expression,
/// and a RequiresExprBodyDecl will be created to hold the parameter t and the
/// template argument list imposed by the compound requirement.
class RequiresExprBodyDecl : public Decl, public DeclContext { … };

/// Represents a static or instance method of a struct/union/class.
///
/// In the terminology of the C++ Standard, these are the (static and
/// non-static) member functions, whether virtual or not.
class CXXMethodDecl : public FunctionDecl { … };

/// Represents a C++ base or member initializer.
///
/// This is part of a constructor initializer that
/// initializes one non-static member variable or one base class. For
/// example, in the following, both 'A(a)' and 'f(3.14159)' are member
/// initializers:
///
/// \code
/// class A { };
/// class B : public A {
///   float f;
/// public:
///   B(A& a) : A(a), f(3.14159) { }
/// };
/// \endcode
class CXXCtorInitializer final { … };

/// Description of a constructor that was inherited from a base class.
class InheritedConstructor { … };

/// Represents a C++ constructor within a class.
///
/// For example:
///
/// \code
/// class X {
/// public:
///   explicit X(int); // represented by a CXXConstructorDecl.
/// };
/// \endcode
class CXXConstructorDecl final
    : public CXXMethodDecl,
      private llvm::TrailingObjects<CXXConstructorDecl, InheritedConstructor,
                                    ExplicitSpecifier> { … };

/// Represents a C++ destructor within a class.
///
/// For example:
///
/// \code
/// class X {
/// public:
///   ~X(); // represented by a CXXDestructorDecl.
/// };
/// \endcode
class CXXDestructorDecl : public CXXMethodDecl { … };

/// Represents a C++ conversion function within a class.
///
/// For example:
///
/// \code
/// class X {
/// public:
///   operator bool();
/// };
/// \endcode
class CXXConversionDecl : public CXXMethodDecl { … };

/// Represents the language in a linkage specification.
///
/// The values are part of the serialization ABI for
/// ASTs and cannot be changed without altering that ABI.
enum class LinkageSpecLanguageIDs { … };

/// Represents a linkage specification.
///
/// For example:
/// \code
///   extern "C" void foo();
/// \endcode
class LinkageSpecDecl : public Decl, public DeclContext { … };

/// Represents C++ using-directive.
///
/// For example:
/// \code
///    using namespace std;
/// \endcode
///
/// \note UsingDirectiveDecl should be Decl not NamedDecl, but we provide
/// artificial names for all using-directives in order to store
/// them in DeclContext effectively.
class UsingDirectiveDecl : public NamedDecl { … };

/// Represents a C++ namespace alias.
///
/// For example:
///
/// \code
/// namespace Foo = Bar;
/// \endcode
class NamespaceAliasDecl : public NamedDecl,
                           public Redeclarable<NamespaceAliasDecl> { … };

/// Implicit declaration of a temporary that was materialized by
/// a MaterializeTemporaryExpr and lifetime-extended by a declaration
class LifetimeExtendedTemporaryDecl final
    : public Decl,
      public Mergeable<LifetimeExtendedTemporaryDecl> { … };

/// Represents a shadow declaration implicitly introduced into a scope by a
/// (resolved) using-declaration or using-enum-declaration to achieve
/// the desired lookup semantics.
///
/// For example:
/// \code
/// namespace A {
///   void foo();
///   void foo(int);
///   struct foo {};
///   enum bar { bar1, bar2 };
/// }
/// namespace B {
///   // add a UsingDecl and three UsingShadowDecls (named foo) to B.
///   using A::foo;
///   // adds UsingEnumDecl and two UsingShadowDecls (named bar1 and bar2) to B.
///   using enum A::bar;
/// }
/// \endcode
class UsingShadowDecl : public NamedDecl, public Redeclarable<UsingShadowDecl> { … };

/// Represents a C++ declaration that introduces decls from somewhere else. It
/// provides a set of the shadow decls so introduced.

class BaseUsingDecl : public NamedDecl { … };

/// Represents a C++ using-declaration.
///
/// For example:
/// \code
///    using someNameSpace::someIdentifier;
/// \endcode
class UsingDecl : public BaseUsingDecl, public Mergeable<UsingDecl> { … };

/// Represents a shadow constructor declaration introduced into a
/// class by a C++11 using-declaration that names a constructor.
///
/// For example:
/// \code
/// struct Base { Base(int); };
/// struct Derived {
///    using Base::Base; // creates a UsingDecl and a ConstructorUsingShadowDecl
/// };
/// \endcode
class ConstructorUsingShadowDecl final : public UsingShadowDecl { … };

/// Represents a C++ using-enum-declaration.
///
/// For example:
/// \code
///    using enum SomeEnumTag ;
/// \endcode

class UsingEnumDecl : public BaseUsingDecl, public Mergeable<UsingEnumDecl> { … };

/// Represents a pack of using declarations that a single
/// using-declarator pack-expanded into.
///
/// \code
/// template<typename ...T> struct X : T... {
///   using T::operator()...;
///   using T::operator T...;
/// };
/// \endcode
///
/// In the second case above, the UsingPackDecl will have the name
/// 'operator T' (which contains an unexpanded pack), but the individual
/// UsingDecls and UsingShadowDecls will have more reasonable names.
class UsingPackDecl final
    : public NamedDecl, public Mergeable<UsingPackDecl>,
      private llvm::TrailingObjects<UsingPackDecl, NamedDecl *> { … };

/// Represents a dependent using declaration which was not marked with
/// \c typename.
///
/// Unlike non-dependent using declarations, these *only* bring through
/// non-types; otherwise they would break two-phase lookup.
///
/// \code
/// template \<class T> class A : public Base<T> {
///   using Base<T>::foo;
/// };
/// \endcode
class UnresolvedUsingValueDecl : public ValueDecl,
                                 public Mergeable<UnresolvedUsingValueDecl> { … };

/// Represents a dependent using declaration which was marked with
/// \c typename.
///
/// \code
/// template \<class T> class A : public Base<T> {
///   using typename Base<T>::foo;
/// };
/// \endcode
///
/// The type associated with an unresolved using typename decl is
/// currently always a typename type.
class UnresolvedUsingTypenameDecl
    : public TypeDecl,
      public Mergeable<UnresolvedUsingTypenameDecl> { … };

/// This node is generated when a using-declaration that was annotated with
/// __attribute__((using_if_exists)) failed to resolve to a known declaration.
/// In that case, Sema builds a UsingShadowDecl whose target is an instance of
/// this declaration, adding it to the current scope. Referring to this
/// declaration in any way is an error.
class UnresolvedUsingIfExistsDecl final : public NamedDecl { … };

/// Represents a C++11 static_assert declaration.
class StaticAssertDecl : public Decl { … };

/// A binding in a decomposition declaration. For instance, given:
///
///   int n[3];
///   auto &[a, b, c] = n;
///
/// a, b, and c are BindingDecls, whose bindings are the expressions
/// x[0], x[1], and x[2] respectively, where x is the implicit
/// DecompositionDecl of type 'int (&)[3]'.
class BindingDecl : public ValueDecl { … };

/// A decomposition declaration. For instance, given:
///
///   int n[3];
///   auto &[a, b, c] = n;
///
/// the second line declares a DecompositionDecl of type 'int (&)[3]', and
/// three BindingDecls (named a, b, and c). An instance of this class is always
/// unnamed, but behaves in almost all other respects like a VarDecl.
class DecompositionDecl final
    : public VarDecl,
      private llvm::TrailingObjects<DecompositionDecl, BindingDecl *> { … };

/// An instance of this class represents the declaration of a property
/// member.  This is a Microsoft extension to C++, first introduced in
/// Visual Studio .NET 2003 as a parallel to similar features in C#
/// and Managed C++.
///
/// A property must always be a non-static class member.
///
/// A property member superficially resembles a non-static data
/// member, except preceded by a property attribute:
///   __declspec(property(get=GetX, put=PutX)) int x;
/// Either (but not both) of the 'get' and 'put' names may be omitted.
///
/// A reference to a property is always an lvalue.  If the lvalue
/// undergoes lvalue-to-rvalue conversion, then a getter name is
/// required, and that member is called with no arguments.
/// If the lvalue is assigned into, then a setter name is required,
/// and that member is called with one argument, the value assigned.
/// Both operations are potentially overloaded.  Compound assignments
/// are permitted, as are the increment and decrement operators.
///
/// The getter and putter methods are permitted to be overloaded,
/// although their return and parameter types are subject to certain
/// restrictions according to the type of the property.
///
/// A property declared using an incomplete array type may
/// additionally be subscripted, adding extra parameters to the getter
/// and putter methods.
class MSPropertyDecl : public DeclaratorDecl { … };

/// Parts of a decomposed MSGuidDecl. Factored out to avoid unnecessary
/// dependencies on DeclCXX.h.
struct MSGuidDeclParts { … };

/// A global _GUID constant. These are implicitly created by UuidAttrs.
///
///   struct _declspec(uuid("01234567-89ab-cdef-0123-456789abcdef")) X{};
///
/// X is a CXXRecordDecl that contains a UuidAttr that references the (unique)
/// MSGuidDecl for the specified UUID.
class MSGuidDecl : public ValueDecl,
                   public Mergeable<MSGuidDecl>,
                   public llvm::FoldingSetNode { … };

/// An artificial decl, representing a global anonymous constant value which is
/// uniquified by value within a translation unit.
///
/// These is currently only used to back the LValue returned by
/// __builtin_source_location, but could potentially be used for other similar
/// situations in the future.
class UnnamedGlobalConstantDecl : public ValueDecl,
                                  public Mergeable<UnnamedGlobalConstantDecl>,
                                  public llvm::FoldingSetNode { … };

/// Insertion operator for diagnostics.  This allows sending an AccessSpecifier
/// into a diagnostic with <<.
const StreamingDiagnostic &operator<<(const StreamingDiagnostic &DB,
                                      AccessSpecifier AS);

} // namespace clang

#endif // LLVM_CLANG_AST_DECLCXX_H