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//===- DeclFriend.h - Classes for C++ friend declarations -------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the section of the AST representing C++ friend
// declarations.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_AST_DECLFRIEND_H
#define LLVM_CLANG_AST_DECLFRIEND_H
#include "clang/AST/Decl.h"
#include "clang/AST/DeclBase.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclTemplate.h"
#include "clang/AST/ExternalASTSource.h"
#include "clang/AST/TypeLoc.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/SourceLocation.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/PointerUnion.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/TrailingObjects.h"
#include <cassert>
#include <iterator>
namespace clang {
class ASTContext;
/// FriendDecl - Represents the declaration of a friend entity,
/// which can be a function, a type, or a templated function or type.
/// For example:
///
/// @code
/// template <typename T> class A {
/// friend int foo(T);
/// friend class B;
/// friend T; // only in C++0x
/// template <typename U> friend class C;
/// template <typename U> friend A& operator+=(A&, const U&) { ... }
/// };
/// @endcode
///
/// The semantic context of a friend decl is its declaring class.
class FriendDecl final
: public Decl,
private llvm::TrailingObjects<FriendDecl, TemplateParameterList *> {
virtual void anchor();
public:
using FriendUnion = llvm::PointerUnion<NamedDecl *, TypeSourceInfo *>;
private:
friend class CXXRecordDecl;
friend class CXXRecordDecl::friend_iterator;
// The declaration that's a friend of this class.
FriendUnion Friend;
// A pointer to the next friend in the sequence.
LazyDeclPtr NextFriend;
// Location of the 'friend' specifier.
SourceLocation FriendLoc;
/// True if this 'friend' declaration is unsupported. Eventually we
/// will support every possible friend declaration, but for now we
/// silently ignore some and set this flag to authorize all access.
LLVM_PREFERRED_TYPE(bool)
unsigned UnsupportedFriend : 1;
// The number of "outer" template parameter lists in non-templatic
// (currently unsupported) friend type declarations, such as
// template <class T> friend class A<T>::B;
unsigned NumTPLists : 31;
FriendDecl(DeclContext *DC, SourceLocation L, FriendUnion Friend,
SourceLocation FriendL,
ArrayRef<TemplateParameterList *> FriendTypeTPLists)
: Decl(Decl::Friend, DC, L), Friend(Friend), FriendLoc(FriendL),
UnsupportedFriend(false), NumTPLists(FriendTypeTPLists.size()) {
for (unsigned i = 0; i < NumTPLists; ++i)
getTrailingObjects<TemplateParameterList *>()[i] = FriendTypeTPLists[i];
}
FriendDecl(EmptyShell Empty, unsigned NumFriendTypeTPLists)
: Decl(Decl::Friend, Empty), UnsupportedFriend(false),
NumTPLists(NumFriendTypeTPLists) {}
FriendDecl *getNextFriend() {
if (!NextFriend.isOffset())
return cast_or_null<FriendDecl>(NextFriend.get(nullptr));
return getNextFriendSlowCase();
}
FriendDecl *getNextFriendSlowCase();
public:
friend class ASTDeclReader;
friend class ASTDeclWriter;
friend class ASTNodeImporter;
friend TrailingObjects;
static FriendDecl *
Create(ASTContext &C, DeclContext *DC, SourceLocation L, FriendUnion Friend_,
SourceLocation FriendL,
ArrayRef<TemplateParameterList *> FriendTypeTPLists = std::nullopt);
static FriendDecl *CreateDeserialized(ASTContext &C, GlobalDeclID ID,
unsigned FriendTypeNumTPLists);
/// If this friend declaration names an (untemplated but possibly
/// dependent) type, return the type; otherwise return null. This
/// is used for elaborated-type-specifiers and, in C++0x, for
/// arbitrary friend type declarations.
TypeSourceInfo *getFriendType() const {
return Friend.dyn_cast<TypeSourceInfo*>();
}
unsigned getFriendTypeNumTemplateParameterLists() const {
return NumTPLists;
}
TemplateParameterList *getFriendTypeTemplateParameterList(unsigned N) const {
assert(N < NumTPLists);
return getTrailingObjects<TemplateParameterList *>()[N];
}
/// If this friend declaration doesn't name a type, return the inner
/// declaration.
NamedDecl *getFriendDecl() const {
return Friend.dyn_cast<NamedDecl *>();
}
/// Retrieves the location of the 'friend' keyword.
SourceLocation getFriendLoc() const {
return FriendLoc;
}
/// Retrieves the source range for the friend declaration.
SourceRange getSourceRange() const override LLVM_READONLY {
if (NamedDecl *ND = getFriendDecl()) {
if (const auto *FD = dyn_cast<FunctionDecl>(ND))
return FD->getSourceRange();
if (const auto *FTD = dyn_cast<FunctionTemplateDecl>(ND))
return FTD->getSourceRange();
if (const auto *CTD = dyn_cast<ClassTemplateDecl>(ND))
return CTD->getSourceRange();
if (const auto *DD = dyn_cast<DeclaratorDecl>(ND)) {
if (DD->getOuterLocStart() != DD->getInnerLocStart())
return DD->getSourceRange();
}
return SourceRange(getFriendLoc(), ND->getEndLoc());
}
else if (TypeSourceInfo *TInfo = getFriendType()) {
SourceLocation StartL =
(NumTPLists == 0) ? getFriendLoc()
: getTrailingObjects<TemplateParameterList *>()[0]
->getTemplateLoc();
return SourceRange(StartL, TInfo->getTypeLoc().getEndLoc());
}
else
return SourceRange(getFriendLoc(), getLocation());
}
/// Determines if this friend kind is unsupported.
bool isUnsupportedFriend() const {
return UnsupportedFriend;
}
void setUnsupportedFriend(bool Unsupported) {
UnsupportedFriend = Unsupported;
}
// Implement isa/cast/dyncast/etc.
static bool classof(const Decl *D) { return classofKind(D->getKind()); }
static bool classofKind(Kind K) { return K == Decl::Friend; }
};
/// An iterator over the friend declarations of a class.
class CXXRecordDecl::friend_iterator {
friend class CXXRecordDecl;
FriendDecl *Ptr;
explicit friend_iterator(FriendDecl *Ptr) : Ptr(Ptr) {}
public:
friend_iterator() = default;
using value_type = FriendDecl *;
using reference = FriendDecl *;
using pointer = FriendDecl *;
using difference_type = int;
using iterator_category = std::forward_iterator_tag;
reference operator*() const { return Ptr; }
friend_iterator &operator++() {
assert(Ptr && "attempt to increment past end of friend list");
Ptr = Ptr->getNextFriend();
return *this;
}
friend_iterator operator++(int) {
friend_iterator tmp = *this;
++*this;
return tmp;
}
bool operator==(const friend_iterator &Other) const {
return Ptr == Other.Ptr;
}
bool operator!=(const friend_iterator &Other) const {
return Ptr != Other.Ptr;
}
friend_iterator &operator+=(difference_type N) {
assert(N >= 0 && "cannot rewind a CXXRecordDecl::friend_iterator");
while (N--)
++*this;
return *this;
}
friend_iterator operator+(difference_type N) const {
friend_iterator tmp = *this;
tmp += N;
return tmp;
}
};
inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_begin() const {
return friend_iterator(getFirstFriend());
}
inline CXXRecordDecl::friend_iterator CXXRecordDecl::friend_end() const {
return friend_iterator(nullptr);
}
inline CXXRecordDecl::friend_range CXXRecordDecl::friends() const {
return friend_range(friend_begin(), friend_end());
}
inline void CXXRecordDecl::pushFriendDecl(FriendDecl *FD) {
assert(!FD->NextFriend && "friend already has next friend?");
FD->NextFriend = data().FirstFriend;
data().FirstFriend = FD;
}
} // namespace clang
#endif // LLVM_CLANG_AST_DECLFRIEND_H
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