DeclFriend.h revision 4fc5089e306fe606f2e3e4fa58063ebab35deb62 
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 "llvm/Support/Compiler.h"
21
22namespace clang {
23
24/// FriendDecl - Represents the declaration of a friend entity,
25/// which can be a function, a type, or a templated function or type.
26//  For example:
27///
28/// @code
29/// template <typename T> class A {
30///   friend int foo(T);
31///   friend class B;
32///   friend T; // only in C++0x
33///   template <typename U> friend class C;
34///   template <typename U> friend A& operator+=(A&, const U&) { ... }
35/// };
36/// @endcode
37///
38/// The semantic context of a friend decl is its declaring class.
39class FriendDecl : public Decl {
40  virtual void anchor();
41public:
42  typedef llvm::PointerUnion<NamedDecl*,TypeSourceInfo*> FriendUnion;
43
44private:
45  // The declaration that's a friend of this class.
46  FriendUnion Friend;
47
48  // A pointer to the next friend in the sequence.
49  LazyDeclPtr NextFriend;
50
51  // Location of the 'friend' specifier.
52  SourceLocation FriendLoc;
53
54  /// True if this 'friend' declaration is unsupported.  Eventually we
55  /// will support every possible friend declaration, but for now we
56  /// silently ignore some and set this flag to authorize all access.
57  bool UnsupportedFriend : 1;
58
59  // The number of "outer" template parameter lists in non-templatic
60  // (currently unsupported) friend type declarations, such as
61  //     template <class T> friend class A<T>::B;
62  unsigned NumTPLists : 31;
63
64  // The tail-allocated friend type template parameter lists (if any).
65  TemplateParameterList* const *getTPLists() const {
66    return reinterpret_cast<TemplateParameterList* const *>(this + 1);
67  }
68  TemplateParameterList **getTPLists() {
69    return reinterpret_cast<TemplateParameterList**>(this + 1);
70  }
71
72  friend class CXXRecordDecl::friend_iterator;
73  friend class CXXRecordDecl;
74
75  FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend,
76             SourceLocation FriendL,
77             ArrayRef<TemplateParameterList*> FriendTypeTPLists)
78    : Decl(Decl::Friend, DC, L),
79      Friend(Friend),
80      NextFriend(),
81      FriendLoc(FriendL),
82      UnsupportedFriend(false),
83      NumTPLists(FriendTypeTPLists.size()) {
84    for (unsigned i = 0; i < NumTPLists; ++i)
85      getTPLists()[i] = FriendTypeTPLists[i];
86  }
87
88  FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
89    : Decl(Decl::Friend, Empty), NextFriend(),
90      NumTPLists(NumFriendTypeTPLists) { }
91
92  FriendDecl *getNextFriend() {
93    if (!NextFriend.isOffset())
94      return cast_or_null<FriendDecl>(NextFriend.get(0));
95    return getNextFriendSlowCase();
96  }
97  FriendDecl *getNextFriendSlowCase();
98
99public:
100  static FriendDecl *Create(ASTContext &C, DeclContext *DC,
101                            SourceLocation L, FriendUnion Friend_,
102                            SourceLocation FriendL,
103                            ArrayRef<TemplateParameterList*> FriendTypeTPLists
104                            = None);
105  static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID,
106                                        unsigned FriendTypeNumTPLists);
107
108  /// If this friend declaration names an (untemplated but possibly
109  /// dependent) type, return the type; otherwise return null.  This
110  /// is used for elaborated-type-specifiers and, in C++0x, for
111  /// arbitrary friend type declarations.
112  TypeSourceInfo *getFriendType() const {
113    return Friend.dyn_cast<TypeSourceInfo*>();
114  }
115  unsigned getFriendTypeNumTemplateParameterLists() const {
116    return NumTPLists;
117  }
118  TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const {
119    assert(N < NumTPLists);
120    return getTPLists()[N];
121  }
122
123  /// If this friend declaration doesn't name a type, return the inner
124  /// declaration.
125  NamedDecl *getFriendDecl() const {
126    return Friend.dyn_cast<NamedDecl*>();
127  }
128
129  /// Retrieves the location of the 'friend' keyword.
130  SourceLocation getFriendLoc() const {
131    return FriendLoc;
132  }
133
134  /// Retrieves the source range for the friend declaration.
135  SourceRange getSourceRange() const LLVM_READONLY {
136    if (NamedDecl *ND = getFriendDecl()) {
137      if (FunctionTemplateDecl *FTD = dyn_cast<FunctionTemplateDecl>(ND))
138        return FTD->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 = (NumTPLists == 0)
147        ? getFriendLoc()
148        : getTPLists()[0]->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.
156  bool isUnsupportedFriend() const {
157    return UnsupportedFriend;
158  }
159  void setUnsupportedFriend(bool Unsupported) {
160    UnsupportedFriend = Unsupported;
161  }
162
163  // Implement isa/cast/dyncast/etc.
164  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
165  static bool classofKind(Kind K) { return K == Decl::Friend; }
166
167  friend class ASTDeclReader;
168  friend class ASTDeclWriter;
169};
170
171/// An iterator over the friend declarations of a class.
172class CXXRecordDecl::friend_iterator {
173  FriendDecl *Ptr;
174
175  friend class CXXRecordDecl;
176  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
177public:
178  friend_iterator() {}
179
180  typedef FriendDecl *value_type;
181  typedef FriendDecl *reference;
182  typedef FriendDecl *pointer;
183  typedef int difference_type;
184  typedef std::forward_iterator_tag iterator_category;
185
186  reference operator*() const { return Ptr; }
187
188  friend_iterator &operator++() {
189    assert(Ptr && "attempt to increment past end of friend list");
190    Ptr = Ptr->getNextFriend();
191    return *this;
192  }
193
194  friend_iterator operator++(int) {
195    friend_iterator tmp = *this;
196    ++*this;
197    return tmp;
198  }
199
200  bool operator==(const friend_iterator &Other) const {
201    return Ptr == Other.Ptr;
202  }
203
204  bool operator!=(const friend_iterator &Other) const {
205    return Ptr != Other.Ptr;
206  }
207
208  friend_iterator &operator+=(difference_type N) {
209    assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
210    while (N--)
211      ++*this;
212    return *this;
213  }
214
215  friend_iterator operator+(difference_type N) const {
216    friend_iterator tmp = *this;
217    tmp += N;
218    return tmp;
219  }
220};
221
222inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
223  return friend_iterator(getFirstFriend());
224}
225
226inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
227  return friend_iterator(0);
228}
229
230inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
231  assert(!FD->NextFriend && "friend already has next friend?");
232  FD->NextFriend = data().FirstFriend;
233  data().FirstFriend = FD;
234}
235
236}
237
238#endif
239