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      1 //===--- DeclVisitor.h - Visitor for Decl subclasses ------------*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines the DeclVisitor interface.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 #ifndef LLVM_CLANG_AST_DECLVISITOR_H
     14 #define LLVM_CLANG_AST_DECLVISITOR_H
     15 
     16 #include "clang/AST/Decl.h"
     17 #include "clang/AST/DeclCXX.h"
     18 #include "clang/AST/DeclFriend.h"
     19 #include "clang/AST/DeclObjC.h"
     20 #include "clang/AST/DeclOpenMP.h"
     21 #include "clang/AST/DeclTemplate.h"
     22 
     23 namespace clang {
     24 namespace declvisitor {
     25 
     26 template <typename T> struct make_ptr       { typedef       T *type; };
     27 template <typename T> struct make_const_ptr { typedef const T *type; };
     28 
     29 /// \brief A simple visitor class that helps create declaration visitors.
     30 template<template <typename> class Ptr, typename ImplClass, typename RetTy=void>
     31 class Base {
     32 public:
     33 
     34 #define PTR(CLASS) typename Ptr<CLASS>::type
     35 #define DISPATCH(NAME, CLASS) \
     36   return static_cast<ImplClass*>(this)->Visit##NAME(static_cast<PTR(CLASS)>(D))
     37 
     38   RetTy Visit(PTR(Decl) D) {
     39     switch (D->getKind()) {
     40 #define DECL(DERIVED, BASE) \
     41       case Decl::DERIVED: DISPATCH(DERIVED##Decl, DERIVED##Decl);
     42 #define ABSTRACT_DECL(DECL)
     43 #include "clang/AST/DeclNodes.inc"
     44     }
     45     llvm_unreachable("Decl that isn't part of DeclNodes.inc!");
     46   }
     47 
     48   // If the implementation chooses not to implement a certain visit
     49   // method, fall back to the parent.
     50 #define DECL(DERIVED, BASE) \
     51   RetTy Visit##DERIVED##Decl(PTR(DERIVED##Decl) D) { DISPATCH(BASE, BASE); }
     52 #include "clang/AST/DeclNodes.inc"
     53 
     54   RetTy VisitDecl(PTR(Decl) D) { return RetTy(); }
     55 
     56 #undef PTR
     57 #undef DISPATCH
     58 };
     59 
     60 } // end namespace declvisitor
     61 
     62 /// \brief A simple visitor class that helps create declaration visitors.
     63 ///
     64 /// This class does not preserve constness of Decl pointers (see also
     65 /// ConstDeclVisitor).
     66 template<typename ImplClass, typename RetTy=void>
     67 class DeclVisitor
     68  : public declvisitor::Base<declvisitor::make_ptr, ImplClass, RetTy> {};
     69 
     70 /// \brief A simple visitor class that helps create declaration visitors.
     71 ///
     72 /// This class preserves constness of Decl pointers (see also DeclVisitor).
     73 template<typename ImplClass, typename RetTy=void>
     74 class ConstDeclVisitor
     75  : public declvisitor::Base<declvisitor::make_const_ptr, ImplClass, RetTy> {};
     76 
     77 }  // end namespace clang
     78 
     79 #endif // LLVM_CLANG_AST_DECLVISITOR_H
     80