llvm/lldb/source/Plugins/ExpressionParser/Clang/ClangASTImporter.h

//===-- ClangASTImporter.h --------------------------------------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H
#define LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H

#include <map>
#include <memory>
#include <set>
#include <vector>

#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTImporter.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/FileSystemOptions.h"

#include "lldb/Host/FileSystem.h"
#include "lldb/Symbol/CompilerDeclContext.h"
#include "lldb/Utility/LLDBAssert.h"
#include "lldb/lldb-types.h"

#include "Plugins/ExpressionParser/Clang/CxxModuleHandler.h"

#include "llvm/ADT/DenseMap.h"

namespace lldb_private {

class ClangASTMetadata;
class TypeSystemClang;

/// Manages and observes all Clang AST node importing in LLDB.
///
/// The ClangASTImporter takes care of two things:
///
/// 1. Keeps track of all ASTImporter instances in LLDB.
///
/// Clang's ASTImporter takes care of importing types from one ASTContext to
/// another. This class expands this concept by allowing copying from several
/// ASTContext instances to several other ASTContext instances. Instead of
/// constructing a new ASTImporter manually to copy over a type/decl, this class
/// can be asked to do this. It will construct a ASTImporter for the caller (and
/// will cache the ASTImporter instance for later use) and then perform the
/// import.
///
/// This mainly prevents that a caller might construct several ASTImporter
/// instances for the same source/target ASTContext combination. As the
/// ASTImporter has an internal state that keeps track of already imported
/// declarations and so on, using only one ASTImporter instance is more
/// efficient and less error-prone than using multiple.
///
/// 2. Keeps track of from where declarations were imported (origin-tracking).
/// The ASTImporter instances in this class usually only performa a minimal
/// import, i.e., only a shallow copy is made that is filled out on demand
/// when more information is requested later on. This requires record-keeping
/// of where any shallow clone originally came from so that the right original
/// declaration can be found and used as the source of any missing information.
class ClangASTImporter { … };

template <class D> class TaggedASTDecl { … };

template <class D2, template <class D> class TD, class D1>
TD<D2> DynCast(TD<D1> source) { … }

template <class D = clang::Decl> class DeclFromParser;
template <class D = clang::Decl> class DeclFromUser;

template <class D> class DeclFromParser : public TaggedASTDecl<D> { … };

template <class D> class DeclFromUser : public TaggedASTDecl<D> { … };

template <class D>
DeclFromUser<D> DeclFromParser<D>::GetOrigin(ClangASTImporter &importer) { … }

template <class D>
DeclFromParser<D> DeclFromUser<D>::Import(clang::ASTContext *dest_ctx,
                                          ClangASTImporter &importer) { … }

} // namespace lldb_private

#endif // LLDB_SOURCE_PLUGINS_EXPRESSIONPARSER_CLANG_CLANGASTIMPORTER_H