llvm/clang-tools-extra/clang-move/HelperDeclRefGraph.h

//===-- UsedHelperDeclFinder.h - AST-based call graph for helper decls ----===//
//
// 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 LLVM_CLANG_TOOLS_EXTRA_CLANG_MOVE_USED_HELPER_DECL_FINDER_H
#define LLVM_CLANG_TOOLS_EXTRA_CLANG_MOVE_USED_HELPER_DECL_FINDER_H

#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/Analysis/CallGraph.h"
#include "llvm/ADT/DenseSet.h"
#include <memory>
#include <vector>

namespace clang {
namespace move {

// A reference graph for finding used/unused helper declarations in a single
// translation unit (e.g. old.cc). We don't reuse CallGraph in clang/Analysis
// because that CallGraph only supports function declarations.
//
// Helper declarations include following types:
//   * function/variable/class definitions in an anonymous namespace.
//   * static function/variable definitions in a global/named namespace.
//
// The reference graph is a directed graph. Each node in the graph represents a
// helper declaration in old.cc or a non-moved/moved declaration (e.g. class,
// function) in old.h, which means each node is associated with a Decl.
//
// To construct the graph, we use AST matcher to find interesting Decls (usually
// a pair of Caller and Callee), and add an edge from the Caller node to the
// Callee node.
//
// Specially, for a class, it might have multiple declarations such methods
// and member variables. We only use a single node to present this class, and
// this node is associated with the class declaration (CXXRecordDecl).
//
// The graph has 3 types of edges:
//   1. moved_decl => helper_decl
//   2. non_moved_decl => helper_decl
//   3. helper_decl => helper_decl
class HelperDeclRefGraph { … };

// A builder helps to construct a call graph of helper declarations.
class HelperDeclRGBuilder : public ast_matchers::MatchFinder::MatchCallback { … };

} // namespace move
} // namespace clang

#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_MOVE_USED_HELPER_DECL_FINDER_H