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 33namespace clang { 34 35class 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. 52class FriendDecl final 53 : public Decl, 54 private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> { 55 virtual void anchor(); 56 57public: 58 using FriendUnion = llvm::PointerUnion<NamedDecl *, TypeSourceInfo *>; 59 60private: 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 LLVM_PREFERRED_TYPE(bool) 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 105public: 106 friend class ASTDeclReader; 107 friend class ASTDeclWriter; 108 friend class ASTNodeImporter; 109 friend TrailingObjects; 110 111 static FriendDecl * 112 Create(ASTContext &C, DeclContext *DC, SourceLocation L, FriendUnion Friend_, 113 SourceLocation FriendL, 114 ArrayRef<TemplateParameterList *> FriendTypeTPLists = std::nullopt); 115 static FriendDecl *CreateDeserialized(ASTContext &C, unsigned ID, 116 unsigned FriendTypeNumTPLists); 117 118 /// If this friend declaration names an (untemplated but possibly 119 /// dependent) type, return the type; otherwise return null. This 120 /// is used for elaborated-type-specifiers and, in C++0x, for 121 /// arbitrary friend type declarations. 122 TypeSourceInfo *getFriendType() const { 123 return Friend.dyn_cast<TypeSourceInfo*>(); 124 } 125 126 unsigned getFriendTypeNumTemplateParameterLists() const { 127 return NumTPLists; 128 } 129 130 TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const { 131 assert(N < NumTPLists); 132 return getTrailingObjects<TemplateParameterList *>()[N]; 133 } 134 135 /// If this friend declaration doesn't name a type, return the inner 136 /// declaration. 137 NamedDecl *getFriendDecl() const { 138 return Friend.dyn_cast<NamedDecl *>(); 139 } 140 141 /// Retrieves the location of the 'friend' keyword. 142 SourceLocation getFriendLoc() const { 143 return FriendLoc; 144 } 145 146 /// Retrieves the source range for the friend declaration. 147 SourceRange getSourceRange() const override LLVM_READONLY { 148 if (NamedDecl *ND = getFriendDecl()) { 149 if (const auto *FD = dyn_cast<FunctionDecl>(ND)) 150 return FD->getSourceRange(); 151 if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND)) 152 return FTD->getSourceRange(); 153 if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND)) 154 return CTD->getSourceRange(); 155 if (const auto *DD = dyn_cast<DeclaratorDecl>(ND)) { 156 if (DD->getOuterLocStart() != DD->getInnerLocStart()) 157 return DD->getSourceRange(); 158 } 159 return SourceRange(getFriendLoc(), ND->getEndLoc()); 160 } 161 else if (TypeSourceInfo *TInfo = getFriendType()) { 162 SourceLocation StartL = 163 (NumTPLists == 0) ? getFriendLoc() 164 : getTrailingObjects<TemplateParameterList *>()[0] 165 ->getTemplateLoc(); 166 return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc()); 167 } 168 else 169 return SourceRange(getFriendLoc(), getLocation()); 170 } 171 172 /// Determines if this friend kind is unsupported. 173 bool isUnsupportedFriend() const { 174 return UnsupportedFriend; 175 } 176 void setUnsupportedFriend(bool Unsupported) { 177 UnsupportedFriend = Unsupported; 178 } 179 180 // Implement isa/cast/dyncast/etc. 181 static bool classof(const Decl *D) { return classofKind(D->getKind()); } 182 static bool classofKind(Kind K) { return K == Decl::Friend; } 183}; 184 185/// An iterator over the friend declarations of a class. 186class CXXRecordDecl::friend_iterator { 187 friend class CXXRecordDecl; 188 189 FriendDecl *Ptr; 190 191 explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {} 192 193public: 194 friend_iterator() = default; 195 196 using value_type = FriendDecl *; 197 using reference = FriendDecl *; 198 using pointer = FriendDecl *; 199 using difference_type = int; 200 using iterator_category = std::forward_iterator_tag; 201 202 reference operator*() const { return Ptr; } 203 204 friend_iterator &operator++() { 205 assert(Ptr && "attempt to increment past end of friend list"); 206 Ptr = Ptr->getNextFriend(); 207 return *this; 208 } 209 210 friend_iterator operator++(int) { 211 friend_iterator tmp = *this; 212 ++*this; 213 return tmp; 214 } 215 216 bool operator==(const friend_iterator &Other) const { 217 return Ptr == Other.Ptr; 218 } 219 220 bool operator!=(const friend_iterator &Other) const { 221 return Ptr != Other.Ptr; 222 } 223 224 friend_iterator &operator+=(difference_type N) { 225 assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator"); 226 while (N--) 227 ++*this; 228 return *this; 229 } 230 231 friend_iterator operator+(difference_type N) const { 232 friend_iterator tmp = *this; 233 tmp += N; 234 return tmp; 235 } 236}; 237 238inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const { 239 return friend_iterator(getFirstFriend()); 240} 241 242inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const { 243 return friend_iterator(nullptr); 244} 245 246inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const { 247 return friend_range(friend_begin(), friend_end()); 248} 249 250inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) { 251 assert(!FD->NextFriend && "friend already has next friend?"); 252 FD->NextFriend = data().FirstFriend; 253 data().FirstFriend = FD; 254} 255 256} // namespace clang 257 258#endif // LLVM_CLANG_AST_DECLFRIEND_H 259