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 final
41    : public Decl,
42      private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> {
43  virtual void anchor();
44public:
45  typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
46
47private:
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
95public:
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.
175class CXXRecordDecl::friend_iterator {
176  FriendDecl *Ptr;
177
178  friend class CXXRecordDecl;
179  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
180public:
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
225inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
226  return friend_iterator(getFirstFriend());
227}
228
229inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
230  return friend_iterator(nullptr);
231}
232
233inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
234  return friend_range(friend_begin(), friend_end());
235}
236
237inline 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