llvm/clang/include/clang/AST/ExternalASTSource.h

//===- ExternalASTSource.h - Abstract External AST Interface ----*- 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 ExternalASTSource interface, which enables
//  construction of AST nodes from some external source.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_EXTERNALASTSOURCE_H
#define LLVM_CLANG_AST_EXTERNALASTSOURCE_H

#include "clang/AST/CharUnits.h"
#include "clang/AST/DeclBase.h"
#include "clang/Basic/LLVM.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IntrusiveRefCntPtr.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator.h"
#include "llvm/Support/PointerLikeTypeTraits.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <iterator>
#include <optional>
#include <utility>

namespace clang {

class ASTConsumer;
class ASTContext;
class ASTSourceDescriptor;
class CXXBaseSpecifier;
class CXXCtorInitializer;
class CXXRecordDecl;
class DeclarationName;
class FieldDecl;
class IdentifierInfo;
class NamedDecl;
class ObjCInterfaceDecl;
class RecordDecl;
class Selector;
class Stmt;
class TagDecl;

/// Abstract interface for external sources of AST nodes.
///
/// External AST sources provide AST nodes constructed from some
/// external source, such as a precompiled header. External AST
/// sources can resolve types and declarations from abstract IDs into
/// actual type and declaration nodes, and read parts of declaration
/// contexts.
class ExternalASTSource : public RefCountedBase<ExternalASTSource> { … };

/// A lazy pointer to an AST node (of base type T) that resides
/// within an external AST source.
///
/// The AST node is identified within the external AST source by a
/// 63-bit offset, and can be retrieved via an operation on the
/// external AST source itself.
template<typename T, typename OffsT, T* (ExternalASTSource::*Get)(OffsT Offset)>
struct LazyOffsetPtr { … };

/// A lazy value (of type T) that is within an AST node of type Owner,
/// where the value might change in later generations of the external AST
/// source.
template<typename Owner, typename T, void (ExternalASTSource::*Update)(Owner)>
struct LazyGenerationalUpdatePtr { … };

} // namespace clang

namespace llvm {

/// Specialize PointerLikeTypeTraits to allow LazyGenerationalUpdatePtr to be
/// placed into a PointerUnion.
PointerLikeTypeTraits<clang::LazyGenerationalUpdatePtr<Owner, T, Update>>;

} // namespace llvm

namespace clang {

/// Represents a lazily-loaded vector of data.
///
/// The lazily-loaded vector of data contains data that is partially loaded
/// from an external source and partially added by local translation. The
/// items loaded from the external source are loaded lazily, when needed for
/// iteration over the complete vector.
template<typename T, typename Source,
         void (Source::*Loader)(SmallVectorImpl<T>&),
         unsigned LoadedStorage = 2, unsigned LocalStorage = 4>
class LazyVector { … };

/// A lazy pointer to a statement.
LazyDeclStmtPtr;

/// A lazy pointer to a declaration.
LazyDeclPtr;

/// A lazy pointer to a set of CXXCtorInitializers.
LazyCXXCtorInitializersPtr;

/// A lazy pointer to a set of CXXBaseSpecifiers.
LazyCXXBaseSpecifiersPtr;

} // namespace clang

#endif // LLVM_CLANG_AST_EXTERNALASTSOURCE_H