Home | History | Annotate | Download | only in AST 
      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 
     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 
     83   FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
     84     : Decl(Decl::Friend, Empty), NextFriend(),
     85       UnsupportedFriend(false),
     86       NumTPLists(NumFriendTypeTPLists) { }
     87 
     88   FriendDecl *getNextFriend() {
     89     if (!NextFriend.isOffset())
     90       return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
     91     return getNextFriendSlowCase();
     92   }
     93   FriendDecl *getNextFriendSlowCase();
     94 
     95 public:
     96   static FriendDecl *Create(ASTContext &C, DeclContext *DC,
     97                             SourceLocation L, FriendUnion Friend_,
     98                             SourceLocation FriendL,
     99                             ArrayRef<TemplateParameterList*> FriendTypeTPLists
    100                             = None);
    101   static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID,
    102                                         unsigned FriendTypeNumTPLists);
    103 
    104   /// If this friend declaration names an (untemplated but possibly
    105   /// dependent) type, return the type; otherwise return null.  This
    106   /// is used for elaborated-type-specifiers and, in C++0x, for
    107   /// arbitrary friend type declarations.
    108   TypeSourceInfo *getFriendType() const {
    109     return Friend.dyn_cast<TypeSourceInfo*>();
    110   }
    111   unsigned getFriendTypeNumTemplateParameterLists() const {
    112     return NumTPLists;
    113   }
    114   TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const {
    115     assert(N < NumTPLists);
    116     return getTrailingObjects<TemplateParameterList *>()[N];
    117   }
    118 
    119   /// If this friend declaration doesn't name a type, return the inner
    120   /// declaration.
    121   NamedDecl *getFriendDecl() const {
    122     return Friend.dyn_cast<NamedDecl*>();
    123   }
    124 
    125   /// Retrieves the location of the 'friend' keyword.
    126   SourceLocation getFriendLoc() const {
    127     return FriendLoc;
    128   }
    129 
    130   /// Retrieves the source range for the friend declaration.
    131   SourceRange getSourceRange() const override LLVM_READONLY {
    132     if (NamedDecl *ND = getFriendDecl()) {
    133       if (FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
    134         return FD->getSourceRange();
    135       if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
    136         return FTD->getSourceRange();
    137       if (ClassTemplateDecl *CTD = dyn_cast<ClassTemplateDecl>(ND))
    138         return CTD->getSourceRange();
    139       if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(ND)) {
    140         if (DD->getOuterLocStart() != DD->getInnerLocStart())
    141           return DD->getSourceRange();
    142       }
    143       return SourceRange(getFriendLoc(), ND->getLocEnd());
    144     }
    145     else if (TypeSourceInfo *TInfo = getFriendType()) {
    146       SourceLocation StartL =
    147           (NumTPLists == 0) ? getFriendLoc()
    148                             : getTrailingObjects<TemplateParameterList *>()[0]
    149                                   ->getTemplateLoc();
    150       return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc());
    151     }
    152     else
    153       return SourceRange(getFriendLoc(), getLocation());
    154   }
    155 
    156   /// Determines if this friend kind is unsupported.
    157   bool isUnsupportedFriend() const {
    158     return UnsupportedFriend;
    159   }
    160   void setUnsupportedFriend(bool Unsupported) {
    161     UnsupportedFriend = Unsupported;
    162   }
    163 
    164   // Implement isa/cast/dyncast/etc.
    165   static bool classof(const Decl *D) { return classofKind(D->getKind()); }
    166   static bool classofKind(Kind K) { return K == Decl::Friend; }
    167 
    168   friend class ASTDeclReader;
    169   friend class ASTDeclWriter;
    170   friend class ASTNodeImporter;
    171   friend TrailingObjects;
    172 };
    173 
    174 /// An iterator over the friend declarations of a class.
    175 class CXXRecordDecl::friend_iterator {
    176   FriendDecl *Ptr;
    177 
    178   friend class CXXRecordDecl;
    179   explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
    180 public:
    181   friend_iterator() {}
    182 
    183   typedef FriendDecl *value_type;
    184   typedef FriendDecl *reference;
    185   typedef FriendDecl *pointer;
    186   typedef int difference_type;
    187   typedef std::forward_iterator_tag iterator_category;
    188 
    189   reference operator*() const { return Ptr; }
    190 
    191   friend_iterator &operator++() {
    192     assert(Ptr && "attempt to increment past end of friend list");
    193     Ptr = Ptr->getNextFriend();
    194     return *this;
    195   }
    196 
    197   friend_iterator operator++(int) {
    198     friend_iterator tmp = *this;
    199     ++*this;
    200     return tmp;
    201   }
    202 
    203   bool operator==(const friend_iterator &Other) const {
    204     return Ptr == Other.Ptr;
    205   }
    206 
    207   bool operator!=(const friend_iterator &Other) const {
    208     return Ptr != Other.Ptr;
    209   }
    210 
    211   friend_iterator &operator+=(difference_type N) {
    212     assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
    213     while (N--)
    214       ++*this;
    215     return *this;
    216   }
    217 
    218   friend_iterator operator+(difference_type N) const {
    219     friend_iterator tmp = *this;
    220     tmp += N;
    221     return tmp;
    222   }
    223 };
    224 
    225 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
    226   return friend_iterator(getFirstFriend());
    227 }
    228 
    229 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
    230   return friend_iterator(nullptr);
    231 }
    232 
    233 inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
    234   return friend_range(friend_begin(), friend_end());
    235 }
    236 
    237 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
    238   assert(!FD->NextFriend && "friend already has next friend?");
    239   FD->NextFriend = data().FirstFriend;
    240   data().FirstFriend = FD;
    241 }
    242 
    243 }
    244 
    245 #endif
    246