clang  9.0.0svn
IdentifierResolver.h
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1 //===- IdentifierResolver.h - Lexical Scope Name lookup ---------*- 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 IdentifierResolver class, which is used for lexical
10 // scoped lookup, based on declaration names.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_CLANG_SEMA_IDENTIFIERRESOLVER_H
15 #define LLVM_CLANG_SEMA_IDENTIFIERRESOLVER_H
16 
17 #include "clang/Basic/LLVM.h"
18 #include "llvm/ADT/SmallVector.h"
19 #include <cassert>
20 #include <cstddef>
21 #include <cstdint>
22 #include <iterator>
23 
24 namespace clang {
25 
26 class Decl;
27 class DeclarationName;
28 class DeclContext;
29 class IdentifierInfo;
30 class LangOptions;
31 class NamedDecl;
32 class Preprocessor;
33 class Scope;
34 
35 /// IdentifierResolver - Keeps track of shadowed decls on enclosing
36 /// scopes. It manages the shadowing chains of declaration names and
37 /// implements efficient decl lookup based on a declaration name.
39  /// IdDeclInfo - Keeps track of information about decls associated
40  /// to a particular declaration name. IdDeclInfos are lazily
41  /// constructed and assigned to a declaration name the first time a
42  /// decl with that declaration name is shadowed in some scope.
43  class IdDeclInfo {
44  public:
45  using DeclsTy = SmallVector<NamedDecl *, 2>;
46 
47  DeclsTy::iterator decls_begin() { return Decls.begin(); }
48  DeclsTy::iterator decls_end() { return Decls.end(); }
49 
50  void AddDecl(NamedDecl *D) { Decls.push_back(D); }
51 
52  /// RemoveDecl - Remove the decl from the scope chain.
53  /// The decl must already be part of the decl chain.
54  void RemoveDecl(NamedDecl *D);
55 
56  /// Insert the given declaration at the given position in the list.
57  void InsertDecl(DeclsTy::iterator Pos, NamedDecl *D) {
58  Decls.insert(Pos, D);
59  }
60 
61  private:
62  DeclsTy Decls;
63  };
64 
65 public:
66  /// iterator - Iterate over the decls of a specified declaration name.
67  /// It will walk or not the parent declaration contexts depending on how
68  /// it was instantiated.
69  class iterator {
70  public:
71  friend class IdentifierResolver;
72 
73  using value_type = NamedDecl *;
74  using reference = NamedDecl *;
75  using pointer = NamedDecl *;
76  using iterator_category = std::input_iterator_tag;
78 
79  /// Ptr - There are 2 forms that 'Ptr' represents:
80  /// 1) A single NamedDecl. (Ptr & 0x1 == 0)
81  /// 2) A IdDeclInfo::DeclsTy::iterator that traverses only the decls of the
82  /// same declaration context. (Ptr & 0x1 == 0x1)
83  uintptr_t Ptr = 0;
84  using BaseIter = IdDeclInfo::DeclsTy::iterator;
85 
86  /// A single NamedDecl. (Ptr & 0x1 == 0)
88  Ptr = reinterpret_cast<uintptr_t>(D);
89  assert((Ptr & 0x1) == 0 && "Invalid Ptr!");
90  }
91 
92  /// A IdDeclInfo::DeclsTy::iterator that walks or not the parent declaration
93  /// contexts depending on 'LookInParentCtx'.
95  Ptr = reinterpret_cast<uintptr_t>(I) | 0x1;
96  }
97 
98  bool isIterator() const { return (Ptr & 0x1); }
99 
101  assert(isIterator() && "Ptr not an iterator!");
102  return reinterpret_cast<BaseIter>(Ptr & ~0x1);
103  }
104 
105  void incrementSlowCase();
106 
107  public:
108  iterator() = default;
109 
110  NamedDecl *operator*() const {
111  if (isIterator())
112  return *getIterator();
113  else
114  return reinterpret_cast<NamedDecl*>(Ptr);
115  }
116 
117  bool operator==(const iterator &RHS) const {
118  return Ptr == RHS.Ptr;
119  }
120  bool operator!=(const iterator &RHS) const {
121  return Ptr != RHS.Ptr;
122  }
123 
124  // Preincrement.
126  if (!isIterator()) // common case.
127  Ptr = 0;
128  else
129  incrementSlowCase();
130  return *this;
131  }
132  };
133 
134  explicit IdentifierResolver(Preprocessor &PP);
136 
137  /// begin - Returns an iterator for decls with the name 'Name'.
139 
140  /// end - Returns an iterator that has 'finished'.
142  return iterator();
143  }
144 
145  /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
146  /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
147  /// true if 'D' belongs to the given declaration context.
148  ///
149  /// \param AllowInlineNamespace If \c true, we are checking whether a prior
150  /// declaration is in scope in a declaration that requires a prior
151  /// declaration (because it is either explicitly qualified or is a
152  /// template instantiation or specialization). In this case, a
153  /// declaration is in scope if it's in the inline namespace set of the
154  /// context.
155  bool isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S = nullptr,
156  bool AllowInlineNamespace = false) const;
157 
158  /// AddDecl - Link the decl to its shadowed decl chain.
159  void AddDecl(NamedDecl *D);
160 
161  /// RemoveDecl - Unlink the decl from its shadowed decl chain.
162  /// The decl must already be part of the decl chain.
163  void RemoveDecl(NamedDecl *D);
164 
165  /// Insert the given declaration after the given iterator
166  /// position.
167  void InsertDeclAfter(iterator Pos, NamedDecl *D);
168 
169  /// Try to add the given declaration to the top level scope, if it
170  /// (or a redeclaration of it) hasn't already been added.
171  ///
172  /// \param D The externally-produced declaration to add.
173  ///
174  /// \param Name The name of the externally-produced declaration.
175  ///
176  /// \returns true if the declaration was added, false otherwise.
178 
179 private:
180  const LangOptions &LangOpt;
181  Preprocessor &PP;
182 
183  class IdDeclInfoMap;
184  IdDeclInfoMap *IdDeclInfos;
185 
186  void updatingIdentifier(IdentifierInfo &II);
187  void readingIdentifier(IdentifierInfo &II);
188 
189  /// FETokenInfo contains a Decl pointer if lower bit == 0.
190  static inline bool isDeclPtr(void *Ptr) {
191  return (reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 0;
192  }
193 
194  /// FETokenInfo contains a IdDeclInfo pointer if lower bit == 1.
195  static inline IdDeclInfo *toIdDeclInfo(void *Ptr) {
196  assert((reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 1
197  && "Ptr not a IdDeclInfo* !");
198  return reinterpret_cast<IdDeclInfo*>(
199  reinterpret_cast<uintptr_t>(Ptr) & ~0x1);
200  }
201 };
202 
203 } // namespace clang
204 
205 #endif // LLVM_CLANG_SEMA_IDENTIFIERRESOLVER_H
iterator(NamedDecl *D)
A single NamedDecl. (Ptr & 0x1 == 0)
bool tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name)
Try to add the given declaration to the top level scope, if it (or a redeclaration of it) hasn&#39;t alre...
bool isDeclInScope(Decl *D, DeclContext *Ctx, Scope *S=nullptr, bool AllowInlineNamespace=false) const
isDeclInScope - If &#39;Ctx&#39; is a function/method, isDeclInScope returns true if &#39;D&#39; is in Scope &#39;S&#39;...
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
The l-value was an access to a declared entity or something equivalently strong, like the address of ...
iterator begin(DeclarationName Name)
begin - Returns an iterator for decls with the name &#39;Name&#39;.
One of these records is kept for each identifier that is lexed.
bool operator!=(const iterator &RHS) const
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:49
iterator end()
end - Returns an iterator that has &#39;finished&#39;.
Forward-declares and imports various common LLVM datatypes that clang wants to use unqualified...
void RemoveDecl(NamedDecl *D)
RemoveDecl - Unlink the decl from its shadowed decl chain.
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:40
IdDeclInfoMap - Associates IdDeclInfos with declaration names.
IdDeclInfo::DeclsTy::iterator BaseIter
__UINTPTR_TYPE__ uintptr_t
An unsigned integer type with the property that any valid pointer to void can be converted to this ty...
Definition: opencl-c-base.h:62
std::input_iterator_tag iterator_category
IdentifierResolver - Keeps track of shadowed decls on enclosing scopes.
Dataflow Directional Tag Classes.
DeclContext - This is used only as base class of specific decl types that can act as declaration cont...
Definition: DeclBase.h:1271
IdentifierResolver(Preprocessor &PP)
bool operator==(const iterator &RHS) const
The name of a declaration.
void InsertDeclAfter(iterator Pos, NamedDecl *D)
Insert the given declaration after the given iterator position.
void AddDecl(NamedDecl *D)
AddDecl - Link the decl to its shadowed decl chain.
iterator(BaseIter I)
A IdDeclInfo::DeclsTy::iterator that walks or not the parent declaration contexts depending on &#39;LookI...
uintptr_t Ptr
Ptr - There are 2 forms that &#39;Ptr&#39; represents: 1) A single NamedDecl.
__PTRDIFF_TYPE__ ptrdiff_t
A signed integer type that is the result of subtracting two pointers.
Definition: opencl-c-base.h:48
This represents a decl that may have a name.
Definition: Decl.h:248
iterator - Iterate over the decls of a specified declaration name.
Engages in a tight little dance with the lexer to efficiently preprocess tokens.
Definition: Preprocessor.h:124