1 | //===- TemplateArgumentVisitor.h - Visitor for TArg 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 TemplateArgumentVisitor interface. |
10 | // |
11 | //===----------------------------------------------------------------------===// |
12 | |
13 | #ifndef LLVM_CLANG_AST_TEMPLATEARGUMENTVISITOR_H |
14 | #define LLVM_CLANG_AST_TEMPLATEARGUMENTVISITOR_H |
15 | |
16 | #include "clang/AST/TemplateBase.h" |
17 | |
18 | namespace clang { |
19 | |
20 | namespace templateargumentvisitor { |
21 | |
22 | /// A simple visitor class that helps create template argument visitors. |
23 | template <template <typename> class Ref, typename ImplClass, |
24 | typename RetTy = void, typename... ParamTys> |
25 | class Base { |
26 | public: |
27 | #define REF(CLASS) typename Ref<CLASS>::type |
28 | #define DISPATCH(NAME) \ |
29 | case TemplateArgument::NAME: \ |
30 | return static_cast<ImplClass *>(this)->Visit##NAME##TemplateArgument( \ |
31 | TA, std::forward<ParamTys>(P)...) |
32 | |
33 | RetTy Visit(REF(TemplateArgument) TA, ParamTys... P) { |
34 | switch (TA.getKind()) { |
35 | DISPATCH(Null); |
36 | DISPATCH(Type); |
37 | DISPATCH(Declaration); |
38 | DISPATCH(NullPtr); |
39 | DISPATCH(Integral); |
40 | DISPATCH(StructuralValue); |
41 | DISPATCH(Template); |
42 | DISPATCH(TemplateExpansion); |
43 | DISPATCH(Expression); |
44 | DISPATCH(Pack); |
45 | } |
46 | llvm_unreachable("TemplateArgument is not covered in switch!" ); |
47 | } |
48 | |
49 | // If the implementation chooses not to implement a certain visit |
50 | // method, fall back to the parent. |
51 | |
52 | #define VISIT_METHOD(CATEGORY) \ |
53 | RetTy Visit##CATEGORY##TemplateArgument(REF(TemplateArgument) TA, \ |
54 | ParamTys... P) { \ |
55 | return VisitTemplateArgument(TA, std::forward<ParamTys>(P)...); \ |
56 | } |
57 | |
58 | VISIT_METHOD(Null); |
59 | VISIT_METHOD(Type); |
60 | VISIT_METHOD(Declaration); |
61 | VISIT_METHOD(NullPtr); |
62 | VISIT_METHOD(Integral); |
63 | VISIT_METHOD(StructuralValue); |
64 | VISIT_METHOD(Template); |
65 | VISIT_METHOD(TemplateExpansion); |
66 | VISIT_METHOD(Expression); |
67 | VISIT_METHOD(Pack); |
68 | |
69 | RetTy VisitTemplateArgument(REF(TemplateArgument), ParamTys...) { |
70 | return RetTy(); |
71 | } |
72 | |
73 | #undef REF |
74 | #undef DISPATCH |
75 | #undef VISIT_METHOD |
76 | }; |
77 | |
78 | } // namespace templateargumentvisitor |
79 | |
80 | /// A simple visitor class that helps create template argument visitors. |
81 | /// |
82 | /// This class does not preserve constness of TemplateArgument references (see |
83 | /// also ConstTemplateArgumentVisitor). |
84 | template <typename ImplClass, typename RetTy = void, typename... ParamTys> |
85 | class TemplateArgumentVisitor |
86 | : public templateargumentvisitor::Base<std::add_lvalue_reference, ImplClass, |
87 | RetTy, ParamTys...> {}; |
88 | |
89 | /// A simple visitor class that helps create template argument visitors. |
90 | /// |
91 | /// This class preserves constness of TemplateArgument references (see also |
92 | /// TemplateArgumentVisitor). |
93 | template <typename ImplClass, typename RetTy = void, typename... ParamTys> |
94 | class ConstTemplateArgumentVisitor |
95 | : public templateargumentvisitor::Base<llvm::make_const_ref, ImplClass, |
96 | RetTy, ParamTys...> {}; |
97 | |
98 | } // namespace clang |
99 | |
100 | #endif // LLVM_CLANG_AST_TEMPLATEARGUMENTVISITOR_H |
101 | |