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1 //===-- DeclFriend.h - Classes for C++ friend declarations -*- 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 section of the AST representing C++ friend
11 // declarations.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_AST_DECLFRIEND_H
16 #define LLVM_CLANG_AST_DECLFRIEND_H
17 
18 #include "clang/AST/DeclCXX.h"
19 #include "clang/AST/DeclTemplate.h"
20 #include "clang/AST/TypeLoc.h"
21 #include "llvm/Support/Compiler.h"
22 
23 namespace clang {
24 
25 /// FriendDecl - Represents the declaration of a friend entity,
26 /// which can be a function, a type, or a templated function or type.
27 //  For example:
28 ///
29 /// @code
30 /// template <typename T> class A {
31 ///   friend int foo(T);
32 ///   friend class B;
33 ///   friend T; // only in C++0x
34 ///   template <typename U> friend class C;
35 ///   template <typename U> friend A& operator+=(A&, const U&) { ... }
36 /// };
37 /// @endcode
38 ///
39 /// The semantic context of a friend decl is its declaring class.
40 class FriendDecl final
41     : public Decl,
42       private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> {
43   virtual void anchor();
44 public:
45   typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
46 
47 private:
48   // The declaration that's a friend of this class.
49   FriendUnion Friend;
50 
51   // A pointer to the next friend in the sequence.
52   LazyDeclPtr NextFriend;
53 
54   // Location of the 'friend' specifier.
55   SourceLocation FriendLoc;
56 
57   /// True if this 'friend' declaration is unsupported.  Eventually we
58   /// will support every possible friend declaration, but for now we
59   /// silently ignore some and set this flag to authorize all access.
60   unsigned UnsupportedFriend : 1;
61 
62   // The number of "outer" template parameter lists in non-templatic
63   // (currently unsupported) friend type declarations, such as
64   //     template <class T> friend class A<T>::B;
65   unsigned NumTPLists : 31;
66 
67   friend class CXXRecordDecl::friend_iterator;
68   friend class CXXRecordDecl;
69 
FriendDecl(DeclContext * DC,SourceLocation L,FriendUnion Friend,SourceLocation FriendL,ArrayRef<TemplateParameterList * > FriendTypeTPLists)70   FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend,
71              SourceLocation FriendL,
72              ArrayRef<TemplateParameterList*> FriendTypeTPLists)
73     : Decl(Decl::Friend, DC, L),
74       Friend(Friend),
75       NextFriend(),
76       FriendLoc(FriendL),
77       UnsupportedFriend(false),
78       NumTPLists(FriendTypeTPLists.size()) {
79     for (unsigned i = 0; i < NumTPLists; ++i)
80       getTrailingObjects<TemplateParameterList *>()[i] = FriendTypeTPLists[i];
81   }
82 
FriendDecl(EmptyShell Empty,unsigned NumFriendTypeTPLists)83   FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
84     : Decl(Decl::Friend, Empty), NextFriend(),
85       NumTPLists(NumFriendTypeTPLists) { }
86 
getNextFriend()87   FriendDecl *getNextFriend() {
88     if (!NextFriend.isOffset())
89       return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
90     return getNextFriendSlowCase();
91   }
92   FriendDecl *getNextFriendSlowCase();
93 
94 public:
95   static FriendDecl *Create(ASTContext &C, DeclContext *DC,
96                             SourceLocation L, FriendUnion Friend_,
97                             SourceLocation FriendL,
98                             ArrayRef<TemplateParameterList*> FriendTypeTPLists
99                             = None);
100   static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID,
101                                         unsigned FriendTypeNumTPLists);
102 
103   /// If this friend declaration names an (untemplated but possibly
104   /// dependent) type, return the type; otherwise return null.  This
105   /// is used for elaborated-type-specifiers and, in C++0x, for
106   /// arbitrary friend type declarations.
getFriendType()107   TypeSourceInfo *getFriendType() const {
108     return Friend.dyn_cast<TypeSourceInfo*>();
109   }
getFriendTypeNumTemplateParameterLists()110   unsigned getFriendTypeNumTemplateParameterLists() const {
111     return NumTPLists;
112   }
getFriendTypeTemplateParameterList(unsigned N)113   TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const {
114     assert(N < NumTPLists);
115     return getTrailingObjects<TemplateParameterList *>()[N];
116   }
117 
118   /// If this friend declaration doesn't name a type, return the inner
119   /// declaration.
getFriendDecl()120   NamedDecl *getFriendDecl() const {
121     return Friend.dyn_cast<NamedDecl*>();
122   }
123 
124   /// Retrieves the location of the 'friend' keyword.
getFriendLoc()125   SourceLocation getFriendLoc() const {
126     return FriendLoc;
127   }
128 
129   /// Retrieves the source range for the friend declaration.
getSourceRange()130   SourceRange getSourceRange() const override LLVM_READONLY {
131     if (NamedDecl *ND = getFriendDecl()) {
132       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
133         return FD->getSourceRange();
134       if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
135         return FTD->getSourceRange();
136       if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(ND))
137         return CTD->getSourceRange();
138       if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(ND)) {
139         if (DD->getOuterLocStart() != DD->getInnerLocStart())
140           return DD->getSourceRange();
141       }
142       return SourceRange(getFriendLoc(), ND->getLocEnd());
143     }
144     else if (TypeSourceInfo *TInfo = getFriendType()) {
145       SourceLocation StartL =
146           (NumTPLists == 0) ? getFriendLoc()
147                             : getTrailingObjects<TemplateParameterList *>()[0]
148                                   ->getTemplateLoc();
149       return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc());
150     }
151     else
152       return SourceRange(getFriendLoc(), getLocation());
153   }
154 
155   /// Determines if this friend kind is unsupported.
isUnsupportedFriend()156   bool isUnsupportedFriend() const {
157     return UnsupportedFriend;
158   }
setUnsupportedFriend(bool Unsupported)159   void setUnsupportedFriend(bool Unsupported) {
160     UnsupportedFriend = Unsupported;
161   }
162 
163   // Implement isa/cast/dyncast/etc.
classof(const Decl * D)164   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
classofKind(Kind K)165   static bool classofKind(Kind K) { return K == Decl::Friend; }
166 
167   friend class ASTDeclReader;
168   friend class ASTDeclWriter;
169   friend TrailingObjects;
170 };
171 
172 /// An iterator over the friend declarations of a class.
173 class CXXRecordDecl::friend_iterator {
174   FriendDecl *Ptr;
175 
176   friend class CXXRecordDecl;
friend_iterator(FriendDecl * Ptr)177   explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
178 public:
friend_iterator()179   friend_iterator() {}
180 
181   typedef FriendDecl *value_type;
182   typedef FriendDecl *reference;
183   typedef FriendDecl *pointer;
184   typedef int difference_type;
185   typedef std::forward_iterator_tag iterator_category;
186 
187   reference operator*() const { return Ptr; }
188 
189   friend_iterator &operator++() {
190     assert(Ptr && "attempt to increment past end of friend list");
191     Ptr = Ptr->getNextFriend();
192     return *this;
193   }
194 
195   friend_iterator operator++(int) {
196     friend_iterator tmp = *this;
197     ++*this;
198     return tmp;
199   }
200 
201   bool operator==(const friend_iterator &Other) const {
202     return Ptr == Other.Ptr;
203   }
204 
205   bool operator!=(const friend_iterator &Other) const {
206     return Ptr != Other.Ptr;
207   }
208 
209   friend_iterator &operator+=(difference_type N) {
210     assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
211     while (N--)
212       ++*this;
213     return *this;
214   }
215 
216   friend_iterator operator+(difference_type N) const {
217     friend_iterator tmp = *this;
218     tmp += N;
219     return tmp;
220   }
221 };
222 
friend_begin()223 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
224   return friend_iterator(getFirstFriend());
225 }
226 
friend_end()227 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
228   return friend_iterator(nullptr);
229 }
230 
friends()231 inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
232   return friend_range(friend_begin(), friend_end());
233 }
234 
pushFriendDecl(FriendDecl * FD)235 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
236   assert(!FD->NextFriend && "friend already has next friend?");
237   FD->NextFriend = data().FirstFriend;
238   data().FirstFriend = FD;
239 }
240 
241 }
242 
243 #endif
244