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 : public Decl {
41   virtual void anchor();
42 public:
43   typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
44 
45 private:
46   // The declaration that's a friend of this class.
47   FriendUnion Friend;
48 
49   // A pointer to the next friend in the sequence.
50   LazyDeclPtr NextFriend;
51 
52   // Location of the 'friend' specifier.
53   SourceLocation FriendLoc;
54 
55   /// True if this 'friend' declaration is unsupported.  Eventually we
56   /// will support every possible friend declaration, but for now we
57   /// silently ignore some and set this flag to authorize all access.
58   bool UnsupportedFriend : 1;
59 
60   // The number of "outer" template parameter lists in non-templatic
61   // (currently unsupported) friend type declarations, such as
62   //     template <class T> friend class A<T>::B;
63   unsigned NumTPLists : 31;
64 
65   // The tail-allocated friend type template parameter lists (if any).
getTPLists()66   TemplateParameterList* const *getTPLists() const {
67     return reinterpret_cast<TemplateParameterList* const *>(this + 1);
68   }
getTPLists()69   TemplateParameterList **getTPLists() {
70     return reinterpret_cast<TemplateParameterList**>(this + 1);
71   }
72 
73   friend class CXXRecordDecl::friend_iterator;
74   friend class CXXRecordDecl;
75 
FriendDecl(DeclContext * DC,SourceLocation L,FriendUnion Friend,SourceLocation FriendL,ArrayRef<TemplateParameterList * > FriendTypeTPLists)76   FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend,
77              SourceLocation FriendL,
78              ArrayRef<TemplateParameterList*> FriendTypeTPLists)
79     : Decl(Decl::Friend, DC, L),
80       Friend(Friend),
81       NextFriend(),
82       FriendLoc(FriendL),
83       UnsupportedFriend(false),
84       NumTPLists(FriendTypeTPLists.size()) {
85     for (unsigned i = 0; i < NumTPLists; ++i)
86       getTPLists()[i] = FriendTypeTPLists[i];
87   }
88 
FriendDecl(EmptyShell Empty,unsigned NumFriendTypeTPLists)89   FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
90     : Decl(Decl::Friend, Empty), NextFriend(),
91       NumTPLists(NumFriendTypeTPLists) { }
92 
getNextFriend()93   FriendDecl *getNextFriend() {
94     if (!NextFriend.isOffset())
95       return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
96     return getNextFriendSlowCase();
97   }
98   FriendDecl *getNextFriendSlowCase();
99 
100 public:
101   static FriendDecl *Create(ASTContext &C, DeclContext *DC,
102                             SourceLocation L, FriendUnion Friend_,
103                             SourceLocation FriendL,
104                             ArrayRef<TemplateParameterList*> FriendTypeTPLists
105                             = None);
106   static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID,
107                                         unsigned FriendTypeNumTPLists);
108 
109   /// If this friend declaration names an (untemplated but possibly
110   /// dependent) type, return the type; otherwise return null.  This
111   /// is used for elaborated-type-specifiers and, in C++0x, for
112   /// arbitrary friend type declarations.
getFriendType()113   TypeSourceInfo *getFriendType() const {
114     return Friend.dyn_cast<TypeSourceInfo*>();
115   }
getFriendTypeNumTemplateParameterLists()116   unsigned getFriendTypeNumTemplateParameterLists() const {
117     return NumTPLists;
118   }
getFriendTypeTemplateParameterList(unsigned N)119   TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const {
120     assert(N < NumTPLists);
121     return getTPLists()[N];
122   }
123 
124   /// If this friend declaration doesn't name a type, return the inner
125   /// declaration.
getFriendDecl()126   NamedDecl *getFriendDecl() const {
127     return Friend.dyn_cast<NamedDecl*>();
128   }
129 
130   /// Retrieves the location of the 'friend' keyword.
getFriendLoc()131   SourceLocation getFriendLoc() const {
132     return FriendLoc;
133   }
134 
135   /// Retrieves the source range for the friend declaration.
getSourceRange()136   SourceRange getSourceRange() const override LLVM_READONLY {
137     if (NamedDecl *ND = getFriendDecl()) {
138       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
139         return FD->getSourceRange();
140       if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
141         return FTD->getSourceRange();
142       if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(ND))
143         return CTD->getSourceRange();
144       if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(ND)) {
145         if (DD->getOuterLocStart() != DD->getInnerLocStart())
146           return DD->getSourceRange();
147       }
148       return SourceRange(getFriendLoc(), ND->getLocEnd());
149     }
150     else if (TypeSourceInfo *TInfo = getFriendType()) {
151       SourceLocation StartL = (NumTPLists == 0)
152         ? getFriendLoc()
153         : getTPLists()[0]->getTemplateLoc();
154       return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc());
155     }
156     else
157       return SourceRange(getFriendLoc(), getLocation());
158   }
159 
160   /// Determines if this friend kind is unsupported.
isUnsupportedFriend()161   bool isUnsupportedFriend() const {
162     return UnsupportedFriend;
163   }
setUnsupportedFriend(bool Unsupported)164   void setUnsupportedFriend(bool Unsupported) {
165     UnsupportedFriend = Unsupported;
166   }
167 
168   // Implement isa/cast/dyncast/etc.
classof(const Decl * D)169   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
classofKind(Kind K)170   static bool classofKind(Kind K) { return K == Decl::Friend; }
171 
172   friend class ASTDeclReader;
173   friend class ASTDeclWriter;
174 };
175 
176 /// An iterator over the friend declarations of a class.
177 class CXXRecordDecl::friend_iterator {
178   FriendDecl *Ptr;
179 
180   friend class CXXRecordDecl;
friend_iterator(FriendDecl * Ptr)181   explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
182 public:
friend_iterator()183   friend_iterator() {}
184 
185   typedef FriendDecl *value_type;
186   typedef FriendDecl *reference;
187   typedef FriendDecl *pointer;
188   typedef int difference_type;
189   typedef std::forward_iterator_tag iterator_category;
190 
191   reference operator*() const { return Ptr; }
192 
193   friend_iterator &operator++() {
194     assert(Ptr && "attempt to increment past end of friend list");
195     Ptr = Ptr->getNextFriend();
196     return *this;
197   }
198 
199   friend_iterator operator++(int) {
200     friend_iterator tmp = *this;
201     ++*this;
202     return tmp;
203   }
204 
205   bool operator==(const friend_iterator &Other) const {
206     return Ptr == Other.Ptr;
207   }
208 
209   bool operator!=(const friend_iterator &Other) const {
210     return Ptr != Other.Ptr;
211   }
212 
213   friend_iterator &operator+=(difference_type N) {
214     assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
215     while (N--)
216       ++*this;
217     return *this;
218   }
219 
220   friend_iterator operator+(difference_type N) const {
221     friend_iterator tmp = *this;
222     tmp += N;
223     return tmp;
224   }
225 };
226 
friend_begin()227 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
228   return friend_iterator(getFirstFriend());
229 }
230 
friend_end()231 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
232   return friend_iterator(nullptr);
233 }
234 
friends()235 inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
236   return friend_range(friend_begin(), friend_end());
237 }
238 
pushFriendDecl(FriendDecl * FD)239 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
240   assert(!FD->NextFriend && "friend already has next friend?");
241   FD->NextFriend = data().FirstFriend;
242   data().FirstFriend = FD;
243 }
244 
245 }
246 
247 #endif
248