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" 21 #include "clang/AST/ExternalASTSource.h" 22 #include "clang/AST/TypeLoc.h" 23 #include "clang/Basic/LLVM.h" 24 #include "clang/Basic/SourceLocation.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; 63 friend class CXXRecordDecl::friend_iterator; 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 84 FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend, 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; 109 friend TrailingObjects; 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. 123 TypeSourceInfo *getFriendType() const { 124 return Friend.dyn_cast<TypeSourceInfo*>(); 125 } 126 127 unsigned getFriendTypeNumTemplateParameterLists() const { 128 return NumTPLists; 129 } 130 131 TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const { 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. 138 NamedDecl *getFriendDecl() const { 139 return Friend.dyn_cast<NamedDecl *>(); 140 } 141 142 /// Retrieves the location of the 'friend' keyword. 143 SourceLocation getFriendLoc() const { 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 } 177 void setUnsupportedFriend(bool Unsupported) { 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. 187 class CXXRecordDecl::friend_iterator { 188 friend class CXXRecordDecl; 189 190 FriendDecl *Ptr; 191 192 explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {} 193 194 public: 195 friend_iterator() = default; 196 197 using value_type = FriendDecl *; 198 using reference = FriendDecl *; 199 using pointer = FriendDecl *; 200 using difference_type = int; 201 using iterator_category = std::forward_iterator_tag; 202 203 reference operator*() const { return Ptr; } 204 205 friend_iterator &operator++() { 206 assert(Ptr && "attempt to increment past end of friend list"); 207 Ptr = Ptr->getNextFriend(); 208 return *this; 209 } 210 211 friend_iterator operator++(int) { 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 } 224 225 friend_iterator &operator+=(difference_type N) { 226 assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator"); 227 while (N--) 228 ++*this; 229 return *this; 230 } 231 232 friend_iterator operator+(difference_type N) const { 233 friend_iterator tmp = *this; 234 tmp += N; 235 return tmp; 236 } 237 }; 238 239 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const { 240 return friend_iterator(getFirstFriend()); 241 } 242 243 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const { 244 return friend_iterator(nullptr); 245 } 246 247 inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const { 248 return friend_range(friend_begin(), friend_end()); 249 } 250 251 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) { 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 260