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
23namespace 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.
40class FriendDecl : public Decl {
41  virtual void anchor();
42public:
43  typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
44
45private:
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).
66  TemplateParameterList* const *getTPLists() const {
67    return reinterpret_cast<TemplateParameterList* const *>(this + 1);
68  }
69  TemplateParameterList **getTPLists() {
70    return reinterpret_cast<TemplateParameterList**>(this + 1);
71  }
72
73  friend class CXXRecordDecl::friend_iterator;
74  friend class CXXRecordDecl;
75
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
89  FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
90    : Decl(Decl::Friend, Empty), NextFriend(),
91      NumTPLists(NumFriendTypeTPLists) { }
92
93  FriendDecl *getNextFriend() {
94    if (!NextFriend.isOffset())
95      return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
96    return getNextFriendSlowCase();
97  }
98  FriendDecl *getNextFriendSlowCase();
99
100public:
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.
113  TypeSourceInfo *getFriendType() const {
114    return Friend.dyn_cast<TypeSourceInfo*>();
115  }
116  unsigned getFriendTypeNumTemplateParameterLists() const {
117    return NumTPLists;
118  }
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.
126  NamedDecl *getFriendDecl() const {
127    return Friend.dyn_cast<NamedDecl*>();
128  }
129
130  /// Retrieves the location of the 'friend' keyword.
131  SourceLocation getFriendLoc() const {
132    return FriendLoc;
133  }
134
135  /// Retrieves the source range for the friend declaration.
136  SourceRange getSourceRange() const override LLVM_READONLY {
137    if (NamedDecl *ND = getFriendDecl()) {
138      if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
139        return FTD->getSourceRange();
140      if (DeclaratorDecl *DD = dyn_cast<DeclaratorDecl>(ND)) {
141        if (DD->getOuterLocStart() != DD->getInnerLocStart())
142          return DD->getSourceRange();
143      }
144      return SourceRange(getFriendLoc(), ND->getLocEnd());
145    }
146    else if (TypeSourceInfo *TInfo = getFriendType()) {
147      SourceLocation StartL = (NumTPLists == 0)
148        ? getFriendLoc()
149        : getTPLists()[0]->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};
171
172/// An iterator over the friend declarations of a class.
173class CXXRecordDecl::friend_iterator {
174  FriendDecl *Ptr;
175
176  friend class CXXRecordDecl;
177  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
178public:
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
223inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
224  return friend_iterator(getFirstFriend());
225}
226
227inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
228  return friend_iterator(nullptr);
229}
230
231inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
232  return friend_range(friend_begin(), friend_end());
233}
234
235inline 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