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      1 //===- UnresolvedSet.h - Unresolved sets of 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 UnresolvedSet class, which is used to store
     10 //  collections of declarations in the AST.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_AST_UNRESOLVEDSET_H
     15 #define LLVM_CLANG_AST_UNRESOLVEDSET_H
     16 
     17 #include "clang/AST/DeclAccessPair.h"
     18 #include "clang/Basic/LLVM.h"
     19 #include "clang/Basic/Specifiers.h"
     20 #include "llvm/ADT/ArrayRef.h"
     21 #include "llvm/ADT/SmallVector.h"
     22 #include "llvm/ADT/iterator.h"
     23 #include <cstddef>
     24 #include <iterator>
     25 
     26 namespace clang {
     27 
     28 class NamedDecl;
     29 
     30 /// The iterator over UnresolvedSets.  Serves as both the const and
     31 /// non-const iterator.
     32 class UnresolvedSetIterator : public llvm::iterator_adaptor_base<
     33                                   UnresolvedSetIterator, DeclAccessPair *,
     34                                   std::random_access_iterator_tag, NamedDecl *,
     35                                   std::ptrdiff_t, NamedDecl *, NamedDecl *> {
     36   friend class ASTUnresolvedSet;
     37   friend class OverloadExpr;
     38   friend class UnresolvedSetImpl;
     39 
     40   explicit UnresolvedSetIterator(DeclAccessPair *Iter)
     41       : iterator_adaptor_base(Iter) {}
     42   explicit UnresolvedSetIterator(const DeclAccessPair *Iter)
     43       : iterator_adaptor_base(const_cast<DeclAccessPair *>(Iter)) {}
     44 
     45 public:
     46   // Work around a bug in MSVC 2013 where explicitly default constructed
     47   // temporaries with defaulted ctors are not zero initialized.
     48   UnresolvedSetIterator() : iterator_adaptor_base(nullptr) {}
     49 
     50   NamedDecl *getDecl() const { return I->getDecl(); }
     51   void setDecl(NamedDecl *ND) const { return I->setDecl(ND); }
     52   AccessSpecifier getAccess() const { return I->getAccess(); }
     53   void setAccess(AccessSpecifier AS) { I->setAccess(AS); }
     54   const DeclAccessPair &getPair() const { return *I; }
     55 
     56   NamedDecl *operator*() const { return getDecl(); }
     57   NamedDecl *operator->() const { return **this; }
     58 };
     59 
     60 /// A set of unresolved declarations.
     61 class UnresolvedSetImpl {
     62   using DeclsTy = SmallVectorImpl<DeclAccessPair>;
     63 
     64   // Don't allow direct construction, and only permit subclassing by
     65   // UnresolvedSet.
     66 private:
     67   template <unsigned N> friend class UnresolvedSet;
     68 
     69   UnresolvedSetImpl() = default;
     70   UnresolvedSetImpl(const UnresolvedSetImpl &) = default;
     71   UnresolvedSetImpl &operator=(const UnresolvedSetImpl &) = default;
     72 
     73   // FIXME: Switch these to "= default" once MSVC supports generating move ops
     74   UnresolvedSetImpl(UnresolvedSetImpl &&) {}
     75   UnresolvedSetImpl &operator=(UnresolvedSetImpl &&) { return *this; }
     76 
     77 public:
     78   // We don't currently support assignment through this iterator, so we might
     79   // as well use the same implementation twice.
     80   using iterator = UnresolvedSetIterator;
     81   using const_iterator = UnresolvedSetIterator;
     82 
     83   iterator begin() { return iterator(decls().begin()); }
     84   iterator end() { return iterator(decls().end()); }
     85 
     86   const_iterator begin() const { return const_iterator(decls().begin()); }
     87   const_iterator end() const { return const_iterator(decls().end()); }
     88 
     89   ArrayRef<DeclAccessPair> pairs() const { return decls(); }
     90 
     91   void addDecl(NamedDecl *D) {
     92     addDecl(D, AS_none);
     93   }
     94 
     95   void addDecl(NamedDecl *D, AccessSpecifier AS) {
     96     decls().push_back(DeclAccessPair::make(D, AS));
     97   }
     98 
     99   /// Replaces the given declaration with the new one, once.
    100   ///
    101   /// \return true if the set changed
    102   bool replace(const NamedDecl* Old, NamedDecl *New) {
    103     for (DeclsTy::iterator I = decls().begin(), E = decls().end(); I != E; ++I)
    104       if (I->getDecl() == Old)
    105         return (I->setDecl(New), true);
    106     return false;
    107   }
    108 
    109   /// Replaces the declaration at the given iterator with the new one,
    110   /// preserving the original access bits.
    111   void replace(iterator I, NamedDecl *New) { I.I->setDecl(New); }
    112 
    113   void replace(iterator I, NamedDecl *New, AccessSpecifier AS) {
    114     I.I->set(New, AS);
    115   }
    116 
    117   void erase(unsigned I) { decls()[I] = decls().pop_back_val(); }
    118 
    119   void erase(iterator I) { *I.I = decls().pop_back_val(); }
    120 
    121   void setAccess(iterator I, AccessSpecifier AS) { I.I->setAccess(AS); }
    122 
    123   void clear() { decls().clear(); }
    124   void set_size(unsigned N) { decls().set_size(N); }
    125 
    126   bool empty() const { return decls().empty(); }
    127   unsigned size() const { return decls().size(); }
    128 
    129   void append(iterator I, iterator E) { decls().append(I.I, E.I); }
    130 
    131   template<typename Iter> void assign(Iter I, Iter E) { decls().assign(I, E); }
    132 
    133   DeclAccessPair &operator[](unsigned I) { return decls()[I]; }
    134   const DeclAccessPair &operator[](unsigned I) const { return decls()[I]; }
    135 
    136 private:
    137   // These work because the only permitted subclass is UnresolvedSetImpl
    138 
    139   DeclsTy &decls() {
    140     return *reinterpret_cast<DeclsTy*>(this);
    141   }
    142   const DeclsTy &decls() const {
    143     return *reinterpret_cast<const DeclsTy*>(this);
    144   }
    145 };
    146 
    147 /// A set of unresolved declarations.
    148 template <unsigned InlineCapacity> class UnresolvedSet :
    149     public UnresolvedSetImpl {
    150   SmallVector<DeclAccessPair, InlineCapacity> Decls;
    151 };
    152 
    153 
    154 } // namespace clang
    155 
    156 #endif // LLVM_CLANG_AST_UNRESOLVEDSET_H
    157