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