llvm/clang/include/clang/AST/Decl.h

//===- Decl.h - Classes for representing 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
//
//===----------------------------------------------------------------------===//
//
//  This file defines the Decl subclasses.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_DECL_H
#define LLVM_CLANG_AST_DECL_H

#include "clang/AST/APNumericStorage.h"
#include "clang/AST/APValue.h"
#include "clang/AST/ASTContextAllocate.h"
#include "clang/AST/DeclAccessPair.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclarationName.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/NestedNameSpecifier.h"
#include "clang/AST/Redeclarable.h"
#include "clang/AST/Type.h"
#include "clang/Basic/AddressSpaces.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/IdentifierTable.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/Linkage.h"
#include "clang/Basic/OperatorKinds.h"
#include "clang/Basic/PartialDiagnostic.h"
#include "clang/Basic/PragmaKinds.h"
#include "clang/Basic/SourceLocation.h"
#include "clang/Basic/Specifiers.h"
#include "clang/Basic/Visibility.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/TrailingObjects.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <optional>
#include <string>
#include <utility>

namespace clang {

class ASTContext;
struct ASTTemplateArgumentListInfo;
class CompoundStmt;
class DependentFunctionTemplateSpecializationInfo;
class EnumDecl;
class Expr;
class FunctionTemplateDecl;
class FunctionTemplateSpecializationInfo;
class FunctionTypeLoc;
class LabelStmt;
class MemberSpecializationInfo;
class Module;
class NamespaceDecl;
class ParmVarDecl;
class RecordDecl;
class Stmt;
class StringLiteral;
class TagDecl;
class TemplateArgumentList;
class TemplateArgumentListInfo;
class TemplateParameterList;
class TypeAliasTemplateDecl;
class UnresolvedSetImpl;
class VarTemplateDecl;
enum class ImplicitParamKind;

/// The top declaration context.
class TranslationUnitDecl : public Decl,
                            public DeclContext,
                            public Redeclarable<TranslationUnitDecl> { … };

/// Represents a `#pragma comment` line. Always a child of
/// TranslationUnitDecl.
class PragmaCommentDecl final
    : public Decl,
      private llvm::TrailingObjects<PragmaCommentDecl, char> { … };

/// Represents a `#pragma detect_mismatch` line. Always a child of
/// TranslationUnitDecl.
class PragmaDetectMismatchDecl final
    : public Decl,
      private llvm::TrailingObjects<PragmaDetectMismatchDecl, char> { … };

/// Declaration context for names declared as extern "C" in C++. This
/// is neither the semantic nor lexical context for such declarations, but is
/// used to check for conflicts with other extern "C" declarations. Example:
///
/// \code
///   namespace N { extern "C" void f(); } // #1
///   void N::f() {}                       // #2
///   namespace M { extern "C" void f(); } // #3
/// \endcode
///
/// The semantic context of #1 is namespace N and its lexical context is the
/// LinkageSpecDecl; the semantic context of #2 is namespace N and its lexical
/// context is the TU. However, both declarations are also visible in the
/// extern "C" context.
///
/// The declaration at #3 finds it is a redeclaration of \c N::f through
/// lookup in the extern "C" context.
class ExternCContextDecl : public Decl, public DeclContext { … };

/// This represents a decl that may have a name.  Many decls have names such
/// as ObjCMethodDecl, but not \@class, etc.
///
/// Note that not every NamedDecl is actually named (e.g., a struct might
/// be anonymous), and not every name is an identifier.
class NamedDecl : public Decl { … };

inline raw_ostream &operator<<(raw_ostream &OS, const NamedDecl &ND) { … }

/// Represents the declaration of a label.  Labels also have a
/// corresponding LabelStmt, which indicates the position that the label was
/// defined at.  For normal labels, the location of the decl is the same as the
/// location of the statement.  For GNU local labels (__label__), the decl
/// location is where the __label__ is.
class LabelDecl : public NamedDecl { … };

/// Represent a C++ namespace.
class NamespaceDecl : public NamedDecl,
                      public DeclContext,
                      public Redeclarable<NamespaceDecl> { … };

class VarDecl;

/// Represent the declaration of a variable (in which case it is
/// an lvalue) a function (in which case it is a function designator) or
/// an enum constant.
class ValueDecl : public NamedDecl { … };

/// A struct with extended info about a syntactic
/// name qualifier, to be used for the case of out-of-line declarations.
struct QualifierInfo { … };

/// Represents a ValueDecl that came out of a declarator.
/// Contains type source information through TypeSourceInfo.
class DeclaratorDecl : public ValueDecl { … };

/// Structure used to store a statement, the constant value to
/// which it was evaluated (if any), and whether or not the statement
/// is an integral constant expression (if known).
struct EvaluatedStmt { … };

/// Represents a variable declaration or definition.
class VarDecl : public DeclaratorDecl, public Redeclarable<VarDecl> { … };

/// Defines the kind of the implicit parameter: is this an implicit parameter
/// with pointer to 'this', 'self', '_cmd', virtual table pointers, captured
/// context or something else.
enum class ImplicitParamKind { … };

class ImplicitParamDecl : public VarDecl { … };

/// Represents a parameter to a function.
class ParmVarDecl : public VarDecl { … };

enum class MultiVersionKind { … };

/// Represents a function declaration or definition.
///
/// Since a given function can be declared several times in a program,
/// there may be several FunctionDecls that correspond to that
/// function. Only one of those FunctionDecls will be found when
/// traversing the list of declarations in the context of the
/// FunctionDecl (e.g., the translation unit); this FunctionDecl
/// contains all of the information known about the function. Other,
/// previous declarations of the function are available via the
/// getPreviousDecl() chain.
class FunctionDecl : public DeclaratorDecl,
                     public DeclContext,
                     public Redeclarable<FunctionDecl> { … };

/// Represents a member of a struct/union/class.
class FieldDecl : public DeclaratorDecl, public Mergeable<FieldDecl> { … };

/// An instance of this object exists for each enum constant
/// that is defined.  For example, in "enum X {a,b}", each of a/b are
/// EnumConstantDecl's, X is an instance of EnumDecl, and the type of a/b is a
/// TagType for the X EnumDecl.
class EnumConstantDecl : public ValueDecl,
                         public Mergeable<EnumConstantDecl>,
                         public APIntStorage { … };

/// Represents a field injected from an anonymous union/struct into the parent
/// scope. These are always implicit.
class IndirectFieldDecl : public ValueDecl,
                          public Mergeable<IndirectFieldDecl> { … };

/// Represents a declaration of a type.
class TypeDecl : public NamedDecl { … };

/// Base class for declarations which introduce a typedef-name.
class TypedefNameDecl : public TypeDecl, public Redeclarable<TypedefNameDecl> { … };

/// Represents the declaration of a typedef-name via the 'typedef'
/// type specifier.
class TypedefDecl : public TypedefNameDecl { … };

/// Represents the declaration of a typedef-name via a C++11
/// alias-declaration.
class TypeAliasDecl : public TypedefNameDecl { … };

/// Represents the declaration of a struct/union/class/enum.
class TagDecl : public TypeDecl,
                public DeclContext,
                public Redeclarable<TagDecl> { … };

/// Represents an enum.  In C++11, enums can be forward-declared
/// with a fixed underlying type, and in C we allow them to be forward-declared
/// with no underlying type as an extension.
class EnumDecl : public TagDecl { … };

/// Enum that represents the different ways arguments are passed to and
/// returned from function calls. This takes into account the target-specific
/// and version-specific rules along with the rules determined by the
/// language.
enum class RecordArgPassingKind { … };

/// Represents a struct/union/class.  For example:
///   struct X;                  // Forward declaration, no "body".
///   union Y { int A, B; };     // Has body with members A and B (FieldDecls).
/// This decl will be marked invalid if *any* members are invalid.
class RecordDecl : public TagDecl { … };

class FileScopeAsmDecl : public Decl { … };

/// A declaration that models statements at global scope. This declaration
/// supports incremental and interactive C/C++.
///
/// \note This is used in libInterpreter, clang -cc1 -fincremental-extensions
/// and in tools such as clang-repl.
class TopLevelStmtDecl : public Decl, public DeclContext { … };

/// Represents a block literal declaration, which is like an
/// unnamed FunctionDecl.  For example:
/// ^{ statement-body }   or   ^(int arg1, float arg2){ statement-body }
class BlockDecl : public Decl, public DeclContext { … };

/// Represents the body of a CapturedStmt, and serves as its DeclContext.
class CapturedDecl final
    : public Decl,
      public DeclContext,
      private llvm::TrailingObjects<CapturedDecl, ImplicitParamDecl *> { … };

/// Describes a module import declaration, which makes the contents
/// of the named module visible in the current translation unit.
///
/// An import declaration imports the named module (or submodule). For example:
/// \code
///   @import std.vector;
/// \endcode
///
/// A C++20 module import declaration imports the named module or partition.
/// Periods are permitted in C++20 module names, but have no semantic meaning.
/// For example:
/// \code
///   import NamedModule;
///   import :SomePartition; // Must be a partition of the current module.
///   import Names.Like.this; // Allowed.
///   import :and.Also.Partition.names;
/// \endcode
///
/// Import declarations can also be implicitly generated from
/// \#include/\#import directives.
class ImportDecl final : public Decl,
                         llvm::TrailingObjects<ImportDecl, SourceLocation> { … };

/// Represents a standard C++ module export declaration.
///
/// For example:
/// \code
///   export void foo();
/// \endcode
class ExportDecl final : public Decl, public DeclContext { … };

/// Represents an empty-declaration.
class EmptyDecl : public Decl { … };

/// HLSLBufferDecl - Represent a cbuffer or tbuffer declaration.
class HLSLBufferDecl final : public NamedDecl, public DeclContext { … };

/// Insertion operator for diagnostics.  This allows sending NamedDecl's
/// into a diagnostic with <<.
inline const StreamingDiagnostic &operator<<(const StreamingDiagnostic &PD,
                                             const NamedDecl *ND) { … }

template<typename decl_type>
void Redeclarable<decl_type>::setPreviousDecl(decl_type *PrevDecl) { … }

// Inline function definitions.

/// Check if the given decl is complete.
///
/// We use this function to break a cycle between the inline definitions in
/// Type.h and Decl.h.
inline bool IsEnumDeclComplete(EnumDecl *ED) { … }

/// Check if the given decl is scoped.
///
/// We use this function to break a cycle between the inline definitions in
/// Type.h and Decl.h.
inline bool IsEnumDeclScoped(EnumDecl *ED) { … }

/// OpenMP variants are mangled early based on their OpenMP context selector.
/// The new name looks likes this:
///  <name> + OpenMPVariantManglingSeparatorStr + <mangled OpenMP context>
static constexpr StringRef getOpenMPVariantManglingSeparatorStr() { … }

/// Returns whether the given FunctionDecl has an __arm[_locally]_streaming
/// attribute.
bool IsArmStreamingFunction(const FunctionDecl *FD,
                            bool IncludeLocallyStreaming);

} // namespace clang

#endif // LLVM_CLANG_AST_DECL_H