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/PointerUnion.h" 27 #include "llvm/Support/Casting.h" 28 #include "llvm/Support/Compiler.h" 29 #include "llvm/Support/TrailingObjects.h" 30 #include <cassert> 31 #include <iterator> 32 33 namespace clang { 34 35 class ASTContext; 36 37 /// FriendDecl - Represents the declaration of a friend entity, 38 /// which can be a function, a type, or a templated function or type. 39 /// For example: 40 /// 41 /// @code 42 /// template <typename T> class A { 43 /// friend int foo(T); 44 /// friend class B; 45 /// friend T; // only in C++0x 46 /// template <typename U> friend class C; 47 /// template <typename U> friend A& operator+=(A&, const U&) { ... } 48 /// }; 49 /// @endcode 50 /// 51 /// The semantic context of a friend decl is its declaring class. 52 class FriendDecl final 53 : public Decl, 54 private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> { 55 virtual void anchor(); 56 57 public: 58 using FriendUnion = llvm::PointerUnion<NamedDecl *, TypeSourceInfo *>; 59 60 private: 61 friend class CXXRecordDecl; 62 friend class CXXRecordDecl::friend_iterator; 63 64 // The declaration that's a friend of this class. 65 FriendUnion Friend; 66 67 // A pointer to the next friend in the sequence. 68 LazyDeclPtr NextFriend; 69 70 // Location of the 'friend' specifier. 71 SourceLocation FriendLoc; 72 73 /// True if this 'friend' declaration is unsupported. Eventually we 74 /// will support every possible friend declaration, but for now we 75 /// silently ignore some and set this flag to authorize all access. 76 unsigned UnsupportedFriend : 1; 77 78 // The number of "outer" template parameter lists in non-templatic 79 // (currently unsupported) friend type declarations, such as 80 // template <class T> friend class A<T>::B; 81 unsigned NumTPLists : 31; 82 83 FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend, 84 SourceLocation FriendL, 85 ArrayRef<TemplateParameterList *> FriendTypeTPLists) 86 : Decl(Decl::Friend, DC, L), Friend(Friend), FriendLoc(FriendL), 87 UnsupportedFriend(false), NumTPLists(FriendTypeTPLists.size()) { 88 for (unsigned i = 0; i < NumTPLists; ++i) 89 getTrailingObjects<TemplateParameterList *>()[i] = FriendTypeTPLists[i]; 90 } 91 92 FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists) 93 : Decl(Decl::Friend, Empty), UnsupportedFriend(false), 94 NumTPLists(NumFriendTypeTPLists) {} 95 96 FriendDecl *getNextFriend() { 97 if (!NextFriend.isOffset()) 98 return cast_or_null<FriendDecl>(NextFriend.get(nullptr)); 99 return getNextFriendSlowCase(); 100 } 101 102 FriendDecl *getNextFriendSlowCase(); 103 104 public: 105 friend class ASTDeclReader; 106 friend class ASTDeclWriter; 107 friend class ASTNodeImporter; 108 friend TrailingObjects; 109 110 static FriendDecl * 111 Create(ASTContext &C, DeclContext *DC, SourceLocation L, FriendUnion Friend_, 112 SourceLocation FriendL, 113 ArrayRef<TemplateParameterList *> FriendTypeTPLists = std::nullopt); 114 static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID, 115 unsigned FriendTypeNumTPLists); 116 117 /// If this friend declaration names an (untemplated but possibly 118 /// dependent) type, return the type; otherwise return null. This 119 /// is used for elaborated-type-specifiers and, in C++0x, for 120 /// arbitrary friend type declarations. 121 TypeSourceInfo *getFriendType() const { 122 return Friend.dyn_cast<TypeSourceInfo*>(); 123 } 124 125 unsigned getFriendTypeNumTemplateParameterLists() const { 126 return NumTPLists; 127 } 128 129 TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const { 130 assert(N < NumTPLists); 131 return getTrailingObjects<TemplateParameterList *>()[N]; 132 } 133 134 /// If this friend declaration doesn't name a type, return the inner 135 /// declaration. 136 NamedDecl *getFriendDecl() const { 137 return Friend.dyn_cast<NamedDecl *>(); 138 } 139 140 /// Retrieves the location of the 'friend' keyword. 141 SourceLocation getFriendLoc() const { 142 return FriendLoc; 143 } 144 145 /// Retrieves the source range for the friend declaration. 146 SourceRange getSourceRange() const override LLVM_READONLY { 147 if (NamedDecl *ND = getFriendDecl()) { 148 if (const auto *FD = dyn_cast<FunctionDecl>(ND)) 149 return FD->getSourceRange(); 150 if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND)) 151 return FTD->getSourceRange(); 152 if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND)) 153 return CTD->getSourceRange(); 154 if (const auto *DD = dyn_cast<DeclaratorDecl>(ND)) { 155 if (DD->getOuterLocStart() != DD->getInnerLocStart()) 156 return DD->getSourceRange(); 157 } 158 return SourceRange(getFriendLoc(), ND->getEndLoc()); 159 } 160 else if (TypeSourceInfo *TInfo = getFriendType()) { 161 SourceLocation StartL = 162 (NumTPLists == 0) ? getFriendLoc() 163 : getTrailingObjects<TemplateParameterList *>()[0] 164 ->getTemplateLoc(); 165 return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc()); 166 } 167 else 168 return SourceRange(getFriendLoc(), getLocation()); 169 } 170 171 /// Determines if this friend kind is unsupported. 172 bool isUnsupportedFriend() const { 173 return UnsupportedFriend; 174 } 175 void setUnsupportedFriend(bool Unsupported) { 176 UnsupportedFriend = Unsupported; 177 } 178 179 // Implement isa/cast/dyncast/etc. 180 static bool classof(const Decl *D) { return classofKind(D->getKind()); } 181 static bool classofKind(Kind K) { return K == Decl::Friend; } 182 }; 183 184 /// An iterator over the friend declarations of a class. 185 class CXXRecordDecl::friend_iterator { 186 friend class CXXRecordDecl; 187 188 FriendDecl *Ptr; 189 190 explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {} 191 192 public: 193 friend_iterator() = default; 194 195 using value_type = FriendDecl *; 196 using reference = FriendDecl *; 197 using pointer = FriendDecl *; 198 using difference_type = int; 199 using iterator_category = std::forward_iterator_tag; 200 201 reference operator*() const { return Ptr; } 202 203 friend_iterator &operator++() { 204 assert(Ptr && "attempt to increment past end of friend list"); 205 Ptr = Ptr->getNextFriend(); 206 return *this; 207 } 208 209 friend_iterator operator++(int) { 210 friend_iterator tmp = *this; 211 ++*this; 212 return tmp; 213 } 214 215 bool operator==(const friend_iterator &Other) const { 216 return Ptr == Other.Ptr; 217 } 218 219 bool operator!=(const friend_iterator &Other) const { 220 return Ptr != Other.Ptr; 221 } 222 223 friend_iterator &operator+=(difference_type N) { 224 assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator"); 225 while (N--) 226 ++*this; 227 return *this; 228 } 229 230 friend_iterator operator+(difference_type N) const { 231 friend_iterator tmp = *this; 232 tmp += N; 233 return tmp; 234 } 235 }; 236 237 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const { 238 return friend_iterator(getFirstFriend()); 239 } 240 241 inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const { 242 return friend_iterator(nullptr); 243 } 244 245 inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const { 246 return friend_range(friend_begin(), friend_end()); 247 } 248 249 inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) { 250 assert(!FD->NextFriend && "friend already has next friend?"); 251 FD->NextFriend = data().FirstFriend; 252 data().FirstFriend = FD; 253 } 254 255 } // namespace clang 256 257 #endif // LLVM_CLANG_AST_DECLFRIEND_H 258