1 //===- AttrVisitor.h - Visitor for Attr subclasses --------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file defines the AttrVisitor interface. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_CLANG_AST_ATTRVISITOR_H 14 #define LLVM_CLANG_AST_ATTRVISITOR_H 15 16 #include "clang/AST/Attr.h" 17 18 namespace clang { 19 20 namespace attrvisitor { 21 22 /// A simple visitor class that helps create attribute visitors. 23 template <template <typename> class Ptr, typename ImplClass, 24 typename RetTy = void, class... ParamTys> 25 class Base { 26 public: 27 #define PTR(CLASS) typename Ptr<CLASS>::type 28 #define DISPATCH(NAME) \ 29 return static_cast<ImplClass *>(this)->Visit##NAME(static_cast<PTR(NAME)>(A)) 30 Visit(PTR (Attr)A)31 RetTy Visit(PTR(Attr) A) { 32 switch (A->getKind()) { 33 34 #define ATTR(NAME) \ 35 case attr::NAME: \ 36 DISPATCH(NAME##Attr); 37 #include "clang/Basic/AttrList.inc" 38 } 39 llvm_unreachable("Attr that isn't part of AttrList.inc!"); 40 } 41 42 // If the implementation chooses not to implement a certain visit 43 // method, fall back to the parent. 44 #define ATTR(NAME) \ 45 RetTy Visit##NAME##Attr(PTR(NAME##Attr) A) { DISPATCH(Attr); } 46 #include "clang/Basic/AttrList.inc" 47 VisitAttr(PTR (Attr))48 RetTy VisitAttr(PTR(Attr)) { return RetTy(); } 49 50 #undef PTR 51 #undef DISPATCH 52 }; 53 54 } // namespace attrvisitor 55 56 /// A simple visitor class that helps create attribute visitors. 57 /// 58 /// This class does not preserve constness of Attr pointers (see 59 /// also ConstAttrVisitor). 60 template <typename ImplClass, typename RetTy = void, typename... ParamTys> 61 class AttrVisitor : public attrvisitor::Base<std::add_pointer, ImplClass, RetTy, 62 ParamTys...> {}; 63 64 /// A simple visitor class that helps create attribute visitors. 65 /// 66 /// This class preserves constness of Attr pointers (see also 67 /// AttrVisitor). 68 template <typename ImplClass, typename RetTy = void, typename... ParamTys> 69 class ConstAttrVisitor 70 : public attrvisitor::Base<llvm::make_const_ptr, ImplClass, RetTy, 71 ParamTys...> {}; 72 73 } // namespace clang 74 75 #endif // LLVM_CLANG_AST_ATTRVISITOR_H 76