--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/clang-tools-extra/clangd/XRefs.h	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,92 @@
+//===--- XRefs.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
+//
+//===----------------------------------------------------------------------===//
+//
+// Features that traverse references between symbols.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_XREFS_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_XREFS_H
+
+#include "FormattedString.h"
+#include "Path.h"
+#include "Protocol.h"
+#include "index/Index.h"
+#include "index/SymbolLocation.h"
+#include "clang/AST/Type.h"
+#include "clang/Format/Format.h"
+#include "clang/Index/IndexSymbol.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/Support/raw_ostream.h"
+#include <vector>
+
+namespace clang {
+namespace clangd {
+class ParsedAST;
+
+// Describes where a symbol is declared and defined (as far as clangd knows).
+// There are three cases:
+//  - a declaration only, no definition is known (e.g. only header seen)
+//  - a declaration and a distinct definition (e.g. function declared in header)
+//  - a declaration and an equal definition (e.g. inline function, or class)
+// For some types of symbol, e.g. macros, definition == declaration always.
+struct LocatedSymbol {
+  // The (unqualified) name of the symbol.
+  std::string Name;
+  // The canonical or best declaration: where most users find its interface.
+  Location PreferredDeclaration;
+  // Where the symbol is defined, if known. May equal PreferredDeclaration.
+  llvm::Optional<Location> Definition;
+};
+llvm::raw_ostream &operator<<(llvm::raw_ostream &, const LocatedSymbol &);
+/// Get definition of symbol at a specified \p Pos.
+/// Multiple locations may be returned, corresponding to distinct symbols.
+std::vector<LocatedSymbol> locateSymbolAt(ParsedAST &AST, Position Pos,
+                                          const SymbolIndex *Index = nullptr);
+
+/// Get all document links
+std::vector<DocumentLink> getDocumentLinks(ParsedAST &AST);
+
+/// Returns highlights for all usages of a symbol at \p Pos.
+std::vector<DocumentHighlight> findDocumentHighlights(ParsedAST &AST,
+                                                      Position Pos);
+
+struct ReferencesResult {
+  std::vector<Location> References;
+  bool HasMore = false;
+};
+/// Returns references of the symbol at a specified \p Pos.
+/// \p Limit limits the number of results returned (0 means no limit).
+ReferencesResult findReferences(ParsedAST &AST, Position Pos, uint32_t Limit,
+                                const SymbolIndex *Index = nullptr);
+
+/// Get info about symbols at \p Pos.
+std::vector<SymbolDetails> getSymbolInfo(ParsedAST &AST, Position Pos);
+
+/// Find the record type references at \p Pos.
+const CXXRecordDecl *findRecordTypeAt(ParsedAST &AST, Position Pos);
+
+/// Given a record type declaration, find its base (parent) types.
+std::vector<const CXXRecordDecl *> typeParents(const CXXRecordDecl *CXXRD);
+
+/// Get type hierarchy information at \p Pos.
+llvm::Optional<TypeHierarchyItem> getTypeHierarchy(
+    ParsedAST &AST, Position Pos, int Resolve, TypeHierarchyDirection Direction,
+    const SymbolIndex *Index = nullptr, PathRef TUPath = PathRef{});
+
+void resolveTypeHierarchy(TypeHierarchyItem &Item, int ResolveLevels,
+                          TypeHierarchyDirection Direction,
+                          const SymbolIndex *Index);
+
+/// Returns all decls that are referenced in the \p FD except local symbols.
+llvm::DenseSet<const Decl *> getNonLocalDeclRefs(ParsedAST &AST,
+                                                 const FunctionDecl *FD);
+} // namespace clangd
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_XREFS_H