1//===- IdentifierResolver.h - Lexical Scope Name lookup ---------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines the IdentifierResolver class, which is used for lexical
11// scoped lookup, based on declaration names.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CLANG_AST_SEMA_IDENTIFIERRESOLVER_H
16#define LLVM_CLANG_AST_SEMA_IDENTIFIERRESOLVER_H
17
18#include "clang/Basic/IdentifierTable.h"
19#include "llvm/ADT/SmallVector.h"
20
21namespace clang {
22
23class ASTContext;
24class Decl;
25class DeclContext;
26class DeclarationName;
27class ExternalPreprocessorSource;
28class NamedDecl;
29class Preprocessor;
30class Scope;
31
32/// IdentifierResolver - Keeps track of shadowed decls on enclosing
33/// scopes.  It manages the shadowing chains of declaration names and
34/// implements efficient decl lookup based on a declaration name.
35class IdentifierResolver {
36
37  /// IdDeclInfo - Keeps track of information about decls associated
38  /// to a particular declaration name. IdDeclInfos are lazily
39  /// constructed and assigned to a declaration name the first time a
40  /// decl with that declaration name is shadowed in some scope.
41  class IdDeclInfo {
42  public:
43    typedef SmallVector<NamedDecl*, 2> DeclsTy;
44
45    inline DeclsTy::iterator decls_begin() { return Decls.begin(); }
46    inline DeclsTy::iterator decls_end() { return Decls.end(); }
47
48    void AddDecl(NamedDecl *D) { Decls.push_back(D); }
49
50    /// RemoveDecl - Remove the decl from the scope chain.
51    /// The decl must already be part of the decl chain.
52    void RemoveDecl(NamedDecl *D);
53
54    /// \brief Insert the given declaration at the given position in the list.
55    void InsertDecl(DeclsTy::iterator Pos, NamedDecl *D) {
56      Decls.insert(Pos, D);
57    }
58
59  private:
60    DeclsTy Decls;
61  };
62
63public:
64
65  /// iterator - Iterate over the decls of a specified declaration name.
66  /// It will walk or not the parent declaration contexts depending on how
67  /// it was instantiated.
68  class iterator {
69  public:
70    typedef NamedDecl *             value_type;
71    typedef NamedDecl *             reference;
72    typedef NamedDecl *             pointer;
73    typedef std::input_iterator_tag iterator_category;
74    typedef std::ptrdiff_t          difference_type;
75
76    /// Ptr - There are 3 forms that 'Ptr' represents:
77    /// 1) A single NamedDecl. (Ptr & 0x1 == 0)
78    /// 2) A IdDeclInfo::DeclsTy::iterator that traverses only the decls of the
79    ///    same declaration context. (Ptr & 0x3 == 0x1)
80    /// 3) A IdDeclInfo::DeclsTy::iterator that traverses the decls of parent
81    ///    declaration contexts too. (Ptr & 0x3 == 0x3)
82    uintptr_t Ptr;
83    typedef IdDeclInfo::DeclsTy::iterator BaseIter;
84
85    /// A single NamedDecl. (Ptr & 0x1 == 0)
86    iterator(NamedDecl *D) {
87      Ptr = reinterpret_cast<uintptr_t>(D);
88      assert((Ptr & 0x1) == 0 && "Invalid Ptr!");
89    }
90    /// A IdDeclInfo::DeclsTy::iterator that walks or not the parent declaration
91    /// contexts depending on 'LookInParentCtx'.
92    iterator(BaseIter I) {
93      Ptr = reinterpret_cast<uintptr_t>(I) | 0x1;
94    }
95
96    bool isIterator() const { return (Ptr & 0x1); }
97
98    BaseIter getIterator() const {
99      assert(isIterator() && "Ptr not an iterator!");
100      return reinterpret_cast<BaseIter>(Ptr & ~0x3);
101    }
102
103    friend class IdentifierResolver;
104
105    void incrementSlowCase();
106  public:
107    iterator() : Ptr(0) {}
108
109    NamedDecl *operator*() const {
110      if (isIterator())
111        return *getIterator();
112      else
113        return reinterpret_cast<NamedDecl*>(Ptr);
114    }
115
116    bool operator==(const iterator &RHS) const {
117      return Ptr == RHS.Ptr;
118    }
119    bool operator!=(const iterator &RHS) const {
120      return Ptr != RHS.Ptr;
121    }
122
123    // Preincrement.
124    iterator& operator++() {
125      if (!isIterator()) // common case.
126        Ptr = 0;
127      else
128        incrementSlowCase();
129      return *this;
130    }
131
132    uintptr_t getAsOpaqueValue() const { return Ptr; }
133
134    static iterator getFromOpaqueValue(uintptr_t P) {
135      iterator Result;
136      Result.Ptr = P;
137      return Result;
138    }
139  };
140
141  /// begin - Returns an iterator for decls with the name 'Name'.
142  iterator begin(DeclarationName Name);
143
144  /// end - Returns an iterator that has 'finished'.
145  iterator end() {
146    return iterator();
147  }
148
149  /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
150  /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
151  /// true if 'D' belongs to the given declaration context.
152  ///
153  /// \param AllowInlineNamespace If \c true, we are checking whether a prior
154  ///        declaration is in scope in a declaration that requires a prior
155  ///        declaration (because it is either explicitly qualified or is a
156  ///        template instantiation or specialization). In this case, a
157  ///        declaration is in scope if it's in the inline namespace set of the
158  ///        context.
159  bool isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S = nullptr,
160                     bool AllowInlineNamespace = false) const;
161
162  /// AddDecl - Link the decl to its shadowed decl chain.
163  void AddDecl(NamedDecl *D);
164
165  /// RemoveDecl - Unlink the decl from its shadowed decl chain.
166  /// The decl must already be part of the decl chain.
167  void RemoveDecl(NamedDecl *D);
168
169  /// \brief Insert the given declaration after the given iterator
170  /// position.
171  void InsertDeclAfter(iterator Pos, NamedDecl *D);
172
173  /// \brief Try to add the given declaration to the top level scope, if it
174  /// (or a redeclaration of it) hasn't already been added.
175  ///
176  /// \param D The externally-produced declaration to add.
177  ///
178  /// \param Name The name of the externally-produced declaration.
179  ///
180  /// \returns true if the declaration was added, false otherwise.
181  bool tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name);
182
183  explicit IdentifierResolver(Preprocessor &PP);
184  ~IdentifierResolver();
185
186private:
187  const LangOptions &LangOpt;
188  Preprocessor &PP;
189
190  class IdDeclInfoMap;
191  IdDeclInfoMap *IdDeclInfos;
192
193  void updatingIdentifier(IdentifierInfo &II);
194  void readingIdentifier(IdentifierInfo &II);
195
196  /// FETokenInfo contains a Decl pointer if lower bit == 0.
197  static inline bool isDeclPtr(void *Ptr) {
198    return (reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 0;
199  }
200
201  /// FETokenInfo contains a IdDeclInfo pointer if lower bit == 1.
202  static inline IdDeclInfo *toIdDeclInfo(void *Ptr) {
203    assert((reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 1
204          && "Ptr not a IdDeclInfo* !");
205    return reinterpret_cast<IdDeclInfo*>(
206                    reinterpret_cast<uintptr_t>(Ptr) & ~0x1
207                                                            );
208  }
209};
210
211} // end namespace clang
212
213#endif
214