lib/Sema/IdentifierResolver.h

   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 "clang/Parse/Scope.h"
  20 #include "clang/AST/Decl.h"
  21 #include "clang/AST/DeclarationName.h"
  22 #include "clang/AST/DeclCXX.h"
  23
  24 namespace clang {
  25
  26 /// IdentifierResolver - Keeps track of shadowed decls on enclosing
  27 /// scopes.  It manages the shadowing chains of declaration names and
  28 /// implements efficent decl lookup based on a declaration name.
  29 class IdentifierResolver {
  30
  31   /// IdDeclInfo - Keeps track of information about decls associated
  32   /// to a particular declaration name. IdDeclInfos are lazily
  33   /// constructed and assigned to a declaration name the first time a
  34   /// decl with that declaration name is shadowed in some scope.
  35   class IdDeclInfo {
  36   public:
  37     typedef llvm::SmallVector<NamedDecl*, 2> DeclsTy;
  38
  39     inline DeclsTy::iterator decls_begin() { return Decls.begin(); }
  40     inline DeclsTy::iterator decls_end() { return Decls.end(); }
  41
  42     void AddDecl(NamedDecl *D) { Decls.push_back(D); }
  43
  44     /// RemoveDecl - Remove the decl from the scope chain.
  45     /// The decl must already be part of the decl chain.
  46     void RemoveDecl(NamedDecl *D);
  47
  48     /// Replaces the Old declaration with the New declaration. If the
  49     /// replacement is successful, returns true. If the old
  50     /// declaration was not found, returns false.
  51     bool ReplaceDecl(NamedDecl *Old, NamedDecl *New);
  52
  53   private:
  54     DeclsTy Decls;
  55   };
  56
  57 public:
  58
  59   /// iterator - Iterate over the decls of a specified declaration name.
  60   /// It will walk or not the parent declaration contexts depending on how
  61   /// it was instantiated.
  62   class iterator {
  63   public:
  64     typedef NamedDecl *             value_type;
  65     typedef NamedDecl *             reference;
  66     typedef NamedDecl *             pointer;
  67     typedef std::input_iterator_tag iterator_category;
  68     typedef std::ptrdiff_t          difference_type;
  69
  70     /// Ptr - There are 3 forms that 'Ptr' represents:
  71     /// 1) A single NamedDecl. (Ptr & 0x1 == 0)
  72     /// 2) A IdDeclInfo::DeclsTy::iterator that traverses only the decls of the
  73     ///    same declaration context. (Ptr & 0x3 == 0x1)
  74     /// 3) A IdDeclInfo::DeclsTy::iterator that traverses the decls of parent
  75     ///    declaration contexts too. (Ptr & 0x3 == 0x3)
  76     uintptr_t Ptr;
  77     typedef IdDeclInfo::DeclsTy::iterator BaseIter;
  78
  79     /// A single NamedDecl. (Ptr & 0x1 == 0)
  80     iterator(NamedDecl *D) {
  81       Ptr = reinterpret_cast<uintptr_t>(D);
  82       assert((Ptr & 0x1) == 0 && "Invalid Ptr!");
  83     }
  84     /// A IdDeclInfo::DeclsTy::iterator that walks or not the parent declaration
  85     /// contexts depending on 'LookInParentCtx'.
  86     iterator(BaseIter I) {
  87       Ptr = reinterpret_cast<uintptr_t>(I) | 0x1;
  88     }
  89
  90     bool isIterator() const { return (Ptr & 0x1); }
  91
  92     BaseIter getIterator() const {
  93       assert(isIterator() && "Ptr not an iterator!");
  94       return reinterpret_cast<BaseIter>(Ptr & ~0x3);
  95     }
  96
  97     friend class IdentifierResolver;
  98   public:
  99     iterator() : Ptr(0) {}
 100
 101     NamedDecl *operator*() const {
 102       if (isIterator())
 103         return *getIterator();
 104       else
 105         return reinterpret_cast<NamedDecl*>(Ptr);
 106     }
 107
 108     bool operator==(const iterator &RHS) const {
 109       return Ptr == RHS.Ptr;
 110     }
 111     bool operator!=(const iterator &RHS) const {
 112       return Ptr != RHS.Ptr;
 113     }
 114
 115     // Preincrement.
 116     iterator& operator++() {
 117       if (!isIterator()) // common case.
 118         Ptr = 0;
 119       else {
 120         NamedDecl *D = **this;
 121         void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
 122         assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
 123         IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
 124
 125         BaseIter I = getIterator();
 126         if (I != Info->decls_begin())
 127           *this = iterator(I-1);
 128         else // No more decls.
 129           *this = iterator();
 130       }
 131       return *this;
 132     }
 133
 134     uintptr_t getAsOpaqueValue() const { return Ptr; }
 135
 136     static iterator getFromOpaqueValue(uintptr_t P) {
 137       iterator Result;
 138       Result.Ptr = P;
 139       return Result;
 140     }
 141   };
 142
 143   /// begin - Returns an iterator for decls with the name 'Name'.
 144   static iterator begin(DeclarationName Name);
 145
 146   /// end - Returns an iterator that has 'finished'.
 147   static iterator end() {
 148     return iterator();
 149   }
 150
 151   /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
 152   /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
 153   /// true if 'D' belongs to the given declaration context.
 154   bool isDeclInScope(Decl *D, DeclContext *Ctx, ASTContext &Context,
 155                      Scope *S = 0) const;
 156
 157   /// AddDecl - Link the decl to its shadowed decl chain.
 158   void AddDecl(NamedDecl *D);
 159
 160   /// RemoveDecl - Unlink the decl from its shadowed decl chain.
 161   /// The decl must already be part of the decl chain.
 162   void RemoveDecl(NamedDecl *D);
 163
 164   /// Replace the decl Old with the new declaration New on its
 165   /// identifier chain. Returns true if the old declaration was found
 166   /// (and, therefore, replaced).
 167   bool ReplaceDecl(NamedDecl *Old, NamedDecl *New);
 168
 169   /// \brief Link the declaration into the chain of declarations for
 170   /// the given identifier.
 171   ///
 172   /// This is a lower-level routine used by the PCH reader to link a
 173   /// declaration into a specific IdentifierInfo before the
 174   /// declaration actually has a name.
 175   void AddDeclToIdentifierChain(IdentifierInfo *II, NamedDecl *D);
 176
 177   explicit IdentifierResolver(const LangOptions &LangOpt);
 178   ~IdentifierResolver();
 179
 180 private:
 181   const LangOptions &LangOpt;
 182
 183   class IdDeclInfoMap;
 184   IdDeclInfoMap *IdDeclInfos;
 185
 186   /// FETokenInfo contains a Decl pointer if lower bit == 0.
 187   static inline bool isDeclPtr(void *Ptr) {
 188     return (reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 0;
 189   }
 190
 191   /// FETokenInfo contains a IdDeclInfo pointer if lower bit == 1.
 192   static inline IdDeclInfo *toIdDeclInfo(void *Ptr) {
 193     assert((reinterpret_cast<uintptr_t>(Ptr) & 0x1) == 1
 194           && "Ptr not a IdDeclInfo* !");
 195     return reinterpret_cast<IdDeclInfo*>(
 196                     reinterpret_cast<uintptr_t>(Ptr) & ~0x1
 197                                                             );
 198   }
 199 };
 200
 201 } // end namespace clang
 202
 203 #endif