include/clang/AST/DeclContextInternals.h

   1 //===-- DeclContextInternals.h - DeclContext Representation -----*- 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 data structures used in the implementation
  11 //  of DeclContext.
  12 //
  13 //===----------------------------------------------------------------------===//
  14 #ifndef LLVM_CLANG_AST_DECLCONTEXTINTERNALS_H
  15 #define LLVM_CLANG_AST_DECLCONTEXTINTERNALS_H
  16
  17 #include "clang/AST/Decl.h"
  18 #include "clang/AST/DeclarationName.h"
  19 #include "clang/AST/DeclCXX.h"
  20 #include "llvm/ADT/DenseMap.h"
  21 #include "llvm/ADT/PointerUnion.h"
  22 #include "llvm/ADT/SmallVector.h"
  23 #include <algorithm>
  24
  25 namespace clang {
  26
  27 class DependentDiagnostic;
  28
  29 /// StoredDeclsList - This is an array of decls optimized a common case of only
  30 /// containing one entry.
  31 struct StoredDeclsList {
  32
  33   /// DeclsTy - When in vector form, this is what the Data pointer points to.
  34   typedef llvm::SmallVector<NamedDecl *, 4> DeclsTy;
  35
  36   /// \brief The stored data, which will be either a pointer to a NamedDecl,
  37   /// or a pointer to a vector.
  38   llvm::PointerUnion<NamedDecl *, DeclsTy *> Data;
  39
  40 public:
  41   StoredDeclsList() {}
  42
  43   StoredDeclsList(const StoredDeclsList &RHS) : Data(RHS.Data) {
  44     if (DeclsTy *RHSVec = RHS.getAsVector())
  45       Data = new DeclsTy(*RHSVec);
  46   }
  47
  48   ~StoredDeclsList() {
  49     // If this is a vector-form, free the vector.
  50     if (DeclsTy *Vector = getAsVector())
  51       delete Vector;
  52   }
  53
  54   StoredDeclsList &operator=(const StoredDeclsList &RHS) {
  55     if (DeclsTy *Vector = getAsVector())
  56       delete Vector;
  57     Data = RHS.Data;
  58     if (DeclsTy *RHSVec = RHS.getAsVector())
  59       Data = new DeclsTy(*RHSVec);
  60     return *this;
  61   }
  62
  63   bool isNull() const { return Data.isNull(); }
  64
  65   NamedDecl *getAsDecl() const {
  66     return Data.dyn_cast<NamedDecl *>();
  67   }
  68
  69   DeclsTy *getAsVector() const {
  70     return Data.dyn_cast<DeclsTy *>();
  71   }
  72
  73   void setOnlyValue(NamedDecl *ND) {
  74     assert(!getAsVector() && "Not inline");
  75     Data = ND;
  76     // Make sure that Data is a plain NamedDecl* so we can use its address
  77     // at getLookupResult.
  78     assert(*(NamedDecl **)&Data == ND &&
  79            "PointerUnion mangles the NamedDecl pointer!");
  80   }
  81
  82   void remove(NamedDecl *D) {
  83     assert(!isNull() && "removing from empty list");
  84     if (NamedDecl *Singleton = getAsDecl()) {
  85       assert(Singleton == D && "list is different singleton");
  86       (void)Singleton;
  87       Data = (NamedDecl *)0;
  88       return;
  89     }
  90
  91     DeclsTy &Vec = *getAsVector();
  92     DeclsTy::iterator I = std::find(Vec.begin(), Vec.end(), D);
  93     assert(I != Vec.end() && "list does not contain decl");
  94     Vec.erase(I);
  95
  96     assert(std::find(Vec.begin(), Vec.end(), D)
  97              == Vec.end() && "list still contains decl");
  98   }
  99
 100   /// getLookupResult - Return an array of all the decls that this list
 101   /// represents.
 102   DeclContext::lookup_result getLookupResult() {
 103     if (isNull())
 104       return DeclContext::lookup_result(DeclContext::lookup_iterator(0),
 105                                         DeclContext::lookup_iterator(0));
 106
 107     // If we have a single NamedDecl, return it.
 108     if (getAsDecl()) {
 109       assert(!isNull() && "Empty list isn't allowed");
 110
 111       // Data is a raw pointer to a NamedDecl*, return it.
 112       void *Ptr = &Data;
 113       return DeclContext::lookup_result((NamedDecl**)Ptr, (NamedDecl**)Ptr+1);
 114     }
 115
 116     assert(getAsVector() && "Must have a vector at this point");
 117     DeclsTy &Vector = *getAsVector();
 118
 119     // Otherwise, we have a range result.
 120     return DeclContext::lookup_result(&Vector[0], &Vector[0]+Vector.size());
 121   }
 122
 123   /// HandleRedeclaration - If this is a redeclaration of an existing decl,
 124   /// replace the old one with D and return true.  Otherwise return false.
 125   bool HandleRedeclaration(NamedDecl *D) {
 126     // Most decls only have one entry in their list, special case it.
 127     if (NamedDecl *OldD = getAsDecl()) {
 128       if (!D->declarationReplaces(OldD))
 129         return false;
 130       setOnlyValue(D);
 131       return true;
 132     }
 133
 134     // Determine if this declaration is actually a redeclaration.
 135     DeclsTy &Vec = *getAsVector();
 136     for (DeclsTy::iterator OD = Vec.begin(), ODEnd = Vec.end();
 137          OD != ODEnd; ++OD) {
 138       NamedDecl *OldD = *OD;
 139       if (D->declarationReplaces(OldD)) {
 140         *OD = D;
 141         return true;
 142       }
 143     }
 144
 145     return false;
 146   }
 147
 148   /// AddSubsequentDecl - This is called on the second and later decl when it is
 149   /// not a redeclaration to merge it into the appropriate place in our list.
 150   ///
 151   void AddSubsequentDecl(NamedDecl *D) {
 152     // If this is the second decl added to the list, convert this to vector
 153     // form.
 154     if (NamedDecl *OldD = getAsDecl()) {
 155       DeclsTy *VT = new DeclsTy();
 156       VT->push_back(OldD);
 157       Data = VT;
 158     }
 159
 160     DeclsTy &Vec = *getAsVector();
 161
 162     // Using directives end up in a special entry which contains only
 163     // other using directives, so all this logic is wasted for them.
 164     // But avoiding the logic wastes time in the far-more-common case
 165     // that we're *not* adding a new using directive.
 166
 167     // Tag declarations always go at the end of the list so that an
 168     // iterator which points at the first tag will start a span of
 169     // decls that only contains tags.
 170     if (D->hasTagIdentifierNamespace())
 171       Vec.push_back(D);
 172
 173     // Resolved using declarations go at the front of the list so that
 174     // they won't show up in other lookup results.  Unresolved using
 175     // declarations (which are always in IDNS_Using | IDNS_Ordinary)
 176     // follow that so that the using declarations will be contiguous.
 177     else if (D->getIdentifierNamespace() & Decl::IDNS_Using) {
 178       DeclsTy::iterator I = Vec.begin();
 179       if (D->getIdentifierNamespace() != Decl::IDNS_Using) {
 180         while (I != Vec.end() &&
 181                (*I)->getIdentifierNamespace() == Decl::IDNS_Using)
 182           ++I;
 183       }
 184       Vec.insert(I, D);
 185
 186     // All other declarations go at the end of the list, but before any
 187     // tag declarations.  But we can be clever about tag declarations
 188     // because there can only ever be one in a scope.
 189     } else if (Vec.back()->hasTagIdentifierNamespace()) {
 190       NamedDecl *TagD = Vec.back();
 191       Vec.back() = D;
 192       Vec.push_back(TagD);
 193     } else
 194       Vec.push_back(D);
 195   }
 196 };
 197
 198 class StoredDeclsMap
 199   : public llvm::DenseMap<DeclarationName, StoredDeclsList> {
 200
 201 public:
 202   static void DestroyAll(StoredDeclsMap *Map, bool Dependent);
 203
 204 private:
 205   friend class ASTContext; // walks the chain deleting these
 206   friend class DeclContext;
 207   llvm::PointerIntPair<StoredDeclsMap*, 1> Previous;
 208 };
 209
 210 class DependentStoredDeclsMap : public StoredDeclsMap {
 211 public:
 212   DependentStoredDeclsMap() : FirstDiagnostic(0) {}
 213
 214 private:
 215   friend class DependentDiagnostic;
 216   friend class DeclContext; // iterates over diagnostics
 217
 218   DependentDiagnostic *FirstDiagnostic;
 219 };
 220
 221 } // end namespace clang
 222
 223 #endif