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DeclFriend.h
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1 //===- DeclFriend.h - Classes for C++ friend declarations -------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the section of the AST representing C++ friend
10 // declarations.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_AST_DECLFRIEND_H
15 #define LLVM_CLANG_AST_DECLFRIEND_H
16 
17 #include "clang/AST/Decl.h"
18 #include "clang/AST/DeclBase.h"
19 #include "clang/AST/DeclCXX.h"
20 #include "clang/AST/DeclTemplate.h"
22 #include "clang/AST/TypeLoc.h"
23 #include "clang/Basic/LLVM.h"
25 #include "llvm/ADT/ArrayRef.h"
26 #include "llvm/ADT/None.h"
27 #include "llvm/ADT/PointerUnion.h"
28 #include "llvm/Support/Casting.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/TrailingObjects.h"
31 #include <cassert>
32 #include <iterator>
33 
34 namespace clang {
35 
36 class ASTContext;
37 
38 /// FriendDecl - Represents the declaration of a friend entity,
39 /// which can be a function, a type, or a templated function or type.
40 /// For example:
41 ///
42 /// @code
43 /// template <typename T> class A {
44 /// friend int foo(T);
45 /// friend class B;
46 /// friend T; // only in C++0x
47 /// template <typename U> friend class C;
48 /// template <typename U> friend A& operator+=(A&, const U&) { ... }
49 /// };
50 /// @endcode
51 ///
52 /// The semantic context of a friend decl is its declaring class.
53 class FriendDecl final
54  : public Decl,
55  private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> {
56  virtual void anchor();
57 
58 public:
59  using FriendUnion = llvm::PointerUnion<NamedDecl *, TypeSourceInfo *>;
60 
61 private:
62  friend class CXXRecordDecl;
64 
65  // The declaration that's a friend of this class.
66  FriendUnion Friend;
67 
68  // A pointer to the next friend in the sequence.
69  LazyDeclPtr NextFriend;
70 
71  // Location of the 'friend' specifier.
72  SourceLocation FriendLoc;
73 
74  /// True if this 'friend' declaration is unsupported. Eventually we
75  /// will support every possible friend declaration, but for now we
76  /// silently ignore some and set this flag to authorize all access.
77  unsigned UnsupportedFriend : 1;
78 
79  // The number of "outer" template parameter lists in non-templatic
80  // (currently unsupported) friend type declarations, such as
81  // template <class T> friend class A<T>::B;
82  unsigned NumTPLists : 31;
83 
85  SourceLocation FriendL,
86  ArrayRef<TemplateParameterList *> FriendTypeTPLists)
87  : Decl(Decl::Friend, DC, L), Friend(Friend), FriendLoc(FriendL),
88  UnsupportedFriend(false), NumTPLists(FriendTypeTPLists.size()) {
89  for (unsigned i = 0; i < NumTPLists; ++i)
90  getTrailingObjects<TemplateParameterList *>()[i] = FriendTypeTPLists[i];
91  }
92 
93  FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
94  : Decl(Decl::Friend, Empty), UnsupportedFriend(false),
95  NumTPLists(NumFriendTypeTPLists) {}
96 
97  FriendDecl *getNextFriend() {
98  if (!NextFriend.isOffset())
99  return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
100  return getNextFriendSlowCase();
101  }
102 
103  FriendDecl *getNextFriendSlowCase();
104 
105 public:
106  friend class ASTDeclReader;
107  friend class ASTDeclWriter;
108  friend class ASTNodeImporter;
110 
111  static FriendDecl *Create(ASTContext &C, DeclContext *DC,
112  SourceLocation L, FriendUnion Friend_,
113  SourceLocation FriendL,
114  ArrayRef<TemplateParameterList*> FriendTypeTPLists
115  = None);
116  static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID,
117  unsigned FriendTypeNumTPLists);
118 
119  /// If this friend declaration names an (untemplated but possibly
120  /// dependent) type, return the type; otherwise return null. This
121  /// is used for elaborated-type-specifiers and, in C++0x, for
122  /// arbitrary friend type declarations.
124  return Friend.dyn_cast<TypeSourceInfo*>();
125  }
126 
128  return NumTPLists;
129  }
130 
132  assert(N < NumTPLists);
133  return getTrailingObjects<TemplateParameterList *>()[N];
134  }
135 
136  /// If this friend declaration doesn't name a type, return the inner
137  /// declaration.
139  return Friend.dyn_cast<NamedDecl *>();
140  }
141 
142  /// Retrieves the location of the 'friend' keyword.
144  return FriendLoc;
145  }
146 
147  /// Retrieves the source range for the friend declaration.
148  SourceRange getSourceRange() const override LLVM_READONLY {
149  if (NamedDecl *ND = getFriendDecl()) {
150  if (const auto *FD = dyn_cast<FunctionDecl>(ND))
151  return FD->getSourceRange();
152  if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND))
153  return FTD->getSourceRange();
154  if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND))
155  return CTD->getSourceRange();
156  if (const auto *DD = dyn_cast<DeclaratorDecl>(ND)) {
157  if (DD->getOuterLocStart() != DD->getInnerLocStart())
158  return DD->getSourceRange();
159  }
160  return SourceRange(getFriendLoc(), ND->getEndLoc());
161  }
162  else if (TypeSourceInfo *TInfo = getFriendType()) {
163  SourceLocation StartL =
164  (NumTPLists == 0) ? getFriendLoc()
165  : getTrailingObjects<TemplateParameterList *>()[0]
166  ->getTemplateLoc();
167  return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc());
168  }
169  else
170  return SourceRange(getFriendLoc(), getLocation());
171  }
172 
173  /// Determines if this friend kind is unsupported.
174  bool isUnsupportedFriend() const {
175  return UnsupportedFriend;
176  }
178  UnsupportedFriend = Unsupported;
179  }
180 
181  // Implement isa/cast/dyncast/etc.
182  static bool classof(const Decl *D) { return classofKind(D->getKind()); }
183  static bool classofKind(Kind K) { return K == Decl::Friend; }
184 };
185 
186 /// An iterator over the friend declarations of a class.
188  friend class CXXRecordDecl;
189 
190  FriendDecl *Ptr;
191 
192  explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
193 
194 public:
195  friend_iterator() = default;
196 
199  using pointer = FriendDecl *;
200  using difference_type = int;
201  using iterator_category = std::forward_iterator_tag;
202 
203  reference operator*() const { return Ptr; }
204 
206  assert(Ptr && "attempt to increment past end of friend list");
207  Ptr = Ptr->getNextFriend();
208  return *this;
209  }
210 
212  friend_iterator tmp = *this;
213  ++*this;
214  return tmp;
215  }
216 
217  bool operator==(const friend_iterator &Other) const {
218  return Ptr == Other.Ptr;
219  }
220 
221  bool operator!=(const friend_iterator &Other) const {
222  return Ptr != Other.Ptr;
223  }
224 
226  assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
227  while (N--)
228  ++*this;
229  return *this;
230  }
231 
233  friend_iterator tmp = *this;
234  tmp += N;
235  return tmp;
236  }
237 };
238 
240  return friend_iterator(getFirstFriend());
241 }
242 
244  return friend_iterator(nullptr);
245 }
246 
248  return friend_range(friend_begin(), friend_end());
249 }
250 
252  assert(!FD->NextFriend && "friend already has next friend?");
253  FD->NextFriend = data().FirstFriend;
254  data().FirstFriend = FD;
255 }
256 
257 } // namespace clang
258 
259 #endif // LLVM_CLANG_AST_DECLFRIEND_H
friend TrailingObjects
Definition: DeclFriend.h:109
unsigned getFriendTypeNumTemplateParameterLists() const
Definition: DeclFriend.h:127
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
Defines the C++ template declaration subclasses.
friend_iterator operator+(difference_type N) const
Definition: DeclFriend.h:232
static FriendDecl * CreateDeserialized(ASTContext &C, unsigned ID, unsigned FriendTypeNumTPLists)
Definition: DeclFriend.cpp:65
A container of type source information.
Definition: Decl.h:86
FriendDecl - Represents the declaration of a friend entity, which can be a function, a type, or a templated function or type.
Definition: DeclFriend.h:53
llvm::PointerUnion< NamedDecl *, TypeSourceInfo * > FriendUnion
Definition: DeclFriend.h:59
Stores a list of template parameters for a TemplateDecl and its derived classes.
Definition: DeclTemplate.h:67
An iterator over the friend declarations of a class.
Definition: DeclFriend.h:187
TypeSourceInfo * getFriendType() const
If this friend declaration names an (untemplated but possibly dependent) type, return the type; other...
Definition: DeclFriend.h:123
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:160
NamedDecl * getFriendDecl() const
If this friend declaration doesn&#39;t name a type, return the inner declaration.
Definition: DeclFriend.h:138
llvm::iterator_range< friend_iterator > friend_range
Definition: DeclCXX.h:664
friend_iterator & operator+=(difference_type N)
Definition: DeclFriend.h:225
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
friend_iterator friend_end() const
Definition: DeclFriend.h:243
TemplateParameterList * getFriendTypeTemplateParameterList(unsigned N) const
Definition: DeclFriend.h:131
A placeholder type used to construct an empty shell of a decl-derived type that will be filled in lat...
Definition: DeclBase.h:104
Defines the clang::TypeLoc interface and its subclasses.
static bool classof(const Decl *D)
Definition: DeclFriend.h:182
#define false
Definition: stdbool.h:17
static FriendDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation L, FriendUnion Friend_, SourceLocation FriendL, ArrayRef< TemplateParameterList *> FriendTypeTPLists=None)
Definition: DeclFriend.cpp:34
Encodes a location in the source.
SourceLocation getFriendLoc() const
Retrieves the location of the &#39;friend&#39; keyword.
Definition: DeclFriend.h:143
friend_iterator friend_begin() const
Definition: DeclFriend.h:239
bool operator==(const friend_iterator &Other) const
Definition: DeclFriend.h:217
static bool classofKind(Kind K)
Definition: DeclFriend.h:183
Dataflow Directional Tag Classes.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1271
Kind getKind() const
Definition: DeclBase.h:432
std::forward_iterator_tag iterator_category
Definition: DeclFriend.h:201
T * get(ExternalASTSource *Source) const
Retrieve the pointer to the AST node that this lazy pointer points to.
friend_range friends() const
Definition: DeclFriend.h:247
friend TrailingObjects
Definition: OpenMPClause.h:98
Defines the C++ Decl subclasses, other than those for templates (found in DeclTemplate.h) and friends (in DeclFriend.h).
Defines the clang::SourceLocation class and associated facilities.
Represents a C++ struct/union/class.
Definition: DeclCXX.h:255
void setUnsupportedFriend(bool Unsupported)
Definition: DeclFriend.h:177
bool isOffset() const
Whether this pointer is currently stored as an offset.
Kind
Lists the kind of concrete classes of Decl.
Definition: DeclBase.h:91
bool operator!=(const friend_iterator &Other) const
Definition: DeclFriend.h:221
SourceRange getSourceRange() const override LLVM_READONLY
Retrieves the source range for the friend declaration.
Definition: DeclFriend.h:148
A trivial tuple used to represent a source range.
This represents a decl that may have a name.
Definition: Decl.h:248
bool isUnsupportedFriend() const
Determines if this friend kind is unsupported.
Definition: DeclFriend.h:174
SourceLocation getLocation() const
Definition: DeclBase.h:429
void pushFriendDecl(FriendDecl *FD)
Definition: DeclFriend.h:251