src/llvm/tools/clang/lib/Sema/IdentifierResolver.cpp

   1 //===- IdentifierResolver.cpp - 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 implements the IdentifierResolver class, which is used for lexical
  11 // scoped lookup, based on declaration names.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "clang/Sema/IdentifierResolver.h"
  16 #include "clang/Sema/Scope.h"
  17 #include "clang/AST/Decl.h"
  18 #include "clang/AST/DeclObjC.h"
  19 #include "clang/Basic/LangOptions.h"
  20 #include "clang/Lex/ExternalPreprocessorSource.h"
  21 #include "clang/Lex/Preprocessor.h"
  22
  23 using namespace clang;
  24
  25 //===----------------------------------------------------------------------===//
  26 // IdDeclInfoMap class
  27 //===----------------------------------------------------------------------===//
  28
  29 /// IdDeclInfoMap - Associates IdDeclInfos with declaration names.
  30 /// Allocates 'pools' (vectors of IdDeclInfos) to avoid allocating each
  31 /// individual IdDeclInfo to heap.
  32 class IdentifierResolver::IdDeclInfoMap {
  33   static const unsigned int POOL_SIZE = 512;
  34
  35   /// We use our own linked-list implementation because it is sadly
  36   /// impossible to add something to a pre-C++0x STL container without
  37   /// a completely unnecessary copy.
  38   struct IdDeclInfoPool {
  39     IdDeclInfoPool(IdDeclInfoPool *Next) : Next(Next) {}
  40
  41     IdDeclInfoPool *Next;
  42     IdDeclInfo Pool[POOL_SIZE];
  43   };
  44
  45   IdDeclInfoPool *CurPool;
  46   unsigned int CurIndex;
  47
  48 public:
  49   IdDeclInfoMap() : CurPool(0), CurIndex(POOL_SIZE) {}
  50
  51   ~IdDeclInfoMap() {
  52     IdDeclInfoPool *Cur = CurPool;
  53     while (IdDeclInfoPool *P = Cur) {
  54       Cur = Cur->Next;
  55       delete P;
  56     }
  57   }
  58
  59   /// Returns the IdDeclInfo associated to the DeclarationName.
  60   /// It creates a new IdDeclInfo if one was not created before for this id.
  61   IdDeclInfo &operator[](DeclarationName Name);
  62 };
  63
  64
  65 //===----------------------------------------------------------------------===//
  66 // IdDeclInfo Implementation
  67 //===----------------------------------------------------------------------===//
  68
  69 /// RemoveDecl - Remove the decl from the scope chain.
  70 /// The decl must already be part of the decl chain.
  71 void IdentifierResolver::IdDeclInfo::RemoveDecl(NamedDecl *D) {
  72   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
  73     if (D == *(I-1)) {
  74       Decls.erase(I-1);
  75       return;
  76     }
  77   }
  78
  79   llvm_unreachable("Didn't find this decl on its identifier's chain!");
  80 }
  81
  82 bool
  83 IdentifierResolver::IdDeclInfo::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
  84   for (DeclsTy::iterator I = Decls.end(); I != Decls.begin(); --I) {
  85     if (Old == *(I-1)) {
  86       *(I - 1) = New;
  87       return true;
  88     }
  89   }
  90
  91   return false;
  92 }
  93
  94
  95 //===----------------------------------------------------------------------===//
  96 // IdentifierResolver Implementation
  97 //===----------------------------------------------------------------------===//
  98
  99 IdentifierResolver::IdentifierResolver(Preprocessor &PP)
 100   : LangOpt(PP.getLangOpts()), PP(PP),
 101     IdDeclInfos(new IdDeclInfoMap) {
 102 }
 103
 104 IdentifierResolver::~IdentifierResolver() {
 105   delete IdDeclInfos;
 106 }
 107
 108 /// isDeclInScope - If 'Ctx' is a function/method, isDeclInScope returns true
 109 /// if 'D' is in Scope 'S', otherwise 'S' is ignored and isDeclInScope returns
 110 /// true if 'D' belongs to the given declaration context.
 111 bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx,
 112                                        ASTContext &Context, Scope *S,
 113                              bool ExplicitInstantiationOrSpecialization) const {
 114   Ctx = Ctx->getRedeclContext();
 115
 116   if (Ctx->isFunctionOrMethod() || S->isFunctionPrototypeScope()) {
 117     // Ignore the scopes associated within transparent declaration contexts.
 118     while (S->getEntity() &&
 119            ((DeclContext *)S->getEntity())->isTransparentContext())
 120       S = S->getParent();
 121
 122     if (S->isDeclScope(D))
 123       return true;
 124     if (LangOpt.CPlusPlus) {
 125       // C++ 3.3.2p3:
 126       // The name declared in a catch exception-declaration is local to the
 127       // handler and shall not be redeclared in the outermost block of the
 128       // handler.
 129       // C++ 3.3.2p4:
 130       // Names declared in the for-init-statement, and in the condition of if,
 131       // while, for, and switch statements are local to the if, while, for, or
 132       // switch statement (including the controlled statement), and shall not be
 133       // redeclared in a subsequent condition of that statement nor in the
 134       // outermost block (or, for the if statement, any of the outermost blocks)
 135       // of the controlled statement.
 136       //
 137       assert(S->getParent() && "No TUScope?");
 138       if (S->getParent()->getFlags() & Scope::ControlScope)
 139         return S->getParent()->isDeclScope(D);
 140     }
 141     return false;
 142   }
 143
 144   DeclContext *DCtx = D->getDeclContext()->getRedeclContext();
 145   return ExplicitInstantiationOrSpecialization
 146            ? Ctx->InEnclosingNamespaceSetOf(DCtx)
 147            : Ctx->Equals(DCtx);
 148 }
 149
 150 /// AddDecl - Link the decl to its shadowed decl chain.
 151 void IdentifierResolver::AddDecl(NamedDecl *D) {
 152   DeclarationName Name = D->getDeclName();
 153   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 154     updatingIdentifier(*II);
 155
 156   void *Ptr = Name.getFETokenInfo<void>();
 157
 158   if (!Ptr) {
 159     Name.setFETokenInfo(D);
 160     return;
 161   }
 162
 163   IdDeclInfo *IDI;
 164
 165   if (isDeclPtr(Ptr)) {
 166     Name.setFETokenInfo(NULL);
 167     IDI = &(*IdDeclInfos)[Name];
 168     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
 169     IDI->AddDecl(PrevD);
 170   } else
 171     IDI = toIdDeclInfo(Ptr);
 172
 173   IDI->AddDecl(D);
 174 }
 175
 176 void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) {
 177   DeclarationName Name = D->getDeclName();
 178   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 179     updatingIdentifier(*II);
 180
 181   void *Ptr = Name.getFETokenInfo<void>();
 182
 183   if (!Ptr) {
 184     AddDecl(D);
 185     return;
 186   }
 187
 188   if (isDeclPtr(Ptr)) {
 189     // We only have a single declaration: insert before or after it,
 190     // as appropriate.
 191     if (Pos == iterator()) {
 192       // Add the new declaration before the existing declaration.
 193       NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
 194       RemoveDecl(PrevD);
 195       AddDecl(D);
 196       AddDecl(PrevD);
 197     } else {
 198       // Add new declaration after the existing declaration.
 199       AddDecl(D);
 200     }
 201
 202     return;
 203   }
 204
 205   // General case: insert the declaration at the appropriate point in the
 206   // list, which already has at least two elements.
 207   IdDeclInfo *IDI = toIdDeclInfo(Ptr);
 208   if (Pos.isIterator()) {
 209     IDI->InsertDecl(Pos.getIterator() + 1, D);
 210   } else
 211     IDI->InsertDecl(IDI->decls_begin(), D);
 212 }
 213
 214 /// RemoveDecl - Unlink the decl from its shadowed decl chain.
 215 /// The decl must already be part of the decl chain.
 216 void IdentifierResolver::RemoveDecl(NamedDecl *D) {
 217   assert(D && "null param passed");
 218   DeclarationName Name = D->getDeclName();
 219   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 220     updatingIdentifier(*II);
 221
 222   void *Ptr = Name.getFETokenInfo<void>();
 223
 224   assert(Ptr && "Didn't find this decl on its identifier's chain!");
 225
 226   if (isDeclPtr(Ptr)) {
 227     assert(D == Ptr && "Didn't find this decl on its identifier's chain!");
 228     Name.setFETokenInfo(NULL);
 229     return;
 230   }
 231
 232   return toIdDeclInfo(Ptr)->RemoveDecl(D);
 233 }
 234
 235 bool IdentifierResolver::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
 236   assert(Old->getDeclName() == New->getDeclName() &&
 237          "Cannot replace a decl with another decl of a different name");
 238
 239   DeclarationName Name = Old->getDeclName();
 240   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 241     updatingIdentifier(*II);
 242
 243   void *Ptr = Name.getFETokenInfo<void>();
 244
 245   if (!Ptr)
 246     return false;
 247
 248   if (isDeclPtr(Ptr)) {
 249     if (Ptr == Old) {
 250       Name.setFETokenInfo(New);
 251       return true;
 252     }
 253     return false;
 254   }
 255
 256   return toIdDeclInfo(Ptr)->ReplaceDecl(Old, New);
 257 }
 258
 259 /// begin - Returns an iterator for decls with name 'Name'.
 260 IdentifierResolver::iterator
 261 IdentifierResolver::begin(DeclarationName Name) {
 262   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 263     readingIdentifier(*II);
 264
 265   void *Ptr = Name.getFETokenInfo<void>();
 266   if (!Ptr) return end();
 267
 268   if (isDeclPtr(Ptr))
 269     return iterator(static_cast<NamedDecl*>(Ptr));
 270
 271   IdDeclInfo *IDI = toIdDeclInfo(Ptr);
 272
 273   IdDeclInfo::DeclsTy::iterator I = IDI->decls_end();
 274   if (I != IDI->decls_begin())
 275     return iterator(I-1);
 276   // No decls found.
 277   return end();
 278 }
 279
 280 namespace {
 281   enum DeclMatchKind {
 282     DMK_Different,
 283     DMK_Replace,
 284     DMK_Ignore
 285   };
 286 }
 287
 288 /// \brief Compare two declarations to see whether they are different or,
 289 /// if they are the same, whether the new declaration should replace the
 290 /// existing declaration.
 291 static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) {
 292   // If the declarations are identical, ignore the new one.
 293   if (Existing == New)
 294     return DMK_Ignore;
 295
 296   // If the declarations have different kinds, they're obviously different.
 297   if (Existing->getKind() != New->getKind())
 298     return DMK_Different;
 299
 300   // If the declarations are redeclarations of each other, keep the newest one.
 301   if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) {
 302     // If the existing declaration is somewhere in the previous declaration
 303     // chain of the new declaration, then prefer the new declaration.
 304     for (Decl::redecl_iterator RD = New->redecls_begin(),
 305                             RDEnd = New->redecls_end();
 306          RD != RDEnd; ++RD) {
 307       if (*RD == Existing)
 308         return DMK_Replace;
 309
 310       if (RD->isCanonicalDecl())
 311         break;
 312     }
 313
 314     return DMK_Ignore;
 315   }
 316
 317   return DMK_Different;
 318 }
 319
 320 bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){
 321   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
 322     readingIdentifier(*II);
 323
 324   void *Ptr = Name.getFETokenInfo<void>();
 325
 326   if (!Ptr) {
 327     Name.setFETokenInfo(D);
 328     return true;
 329   }
 330
 331   IdDeclInfo *IDI;
 332
 333   if (isDeclPtr(Ptr)) {
 334     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
 335
 336     switch (compareDeclarations(PrevD, D)) {
 337     case DMK_Different:
 338       break;
 339
 340     case DMK_Ignore:
 341       return false;
 342
 343     case DMK_Replace:
 344       Name.setFETokenInfo(D);
 345       return true;
 346     }
 347
 348     Name.setFETokenInfo(NULL);
 349     IDI = &(*IdDeclInfos)[Name];
 350
 351     // If the existing declaration is not visible in translation unit scope,
 352     // then add the new top-level declaration first.
 353     if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
 354       IDI->AddDecl(D);
 355       IDI->AddDecl(PrevD);
 356     } else {
 357       IDI->AddDecl(PrevD);
 358       IDI->AddDecl(D);
 359     }
 360     return true;
 361   }
 362
 363   IDI = toIdDeclInfo(Ptr);
 364
 365   // See whether this declaration is identical to any existing declarations.
 366   // If not, find the right place to insert it.
 367   for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(),
 368                                   IEnd = IDI->decls_end();
 369        I != IEnd; ++I) {
 370
 371     switch (compareDeclarations(*I, D)) {
 372     case DMK_Different:
 373       break;
 374
 375     case DMK_Ignore:
 376       return false;
 377
 378     case DMK_Replace:
 379       *I = D;
 380       return true;
 381     }
 382
 383     if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
 384       // We've found a declaration that is not visible from the translation
 385       // unit (it's in an inner scope). Insert our declaration here.
 386       IDI->InsertDecl(I, D);
 387       return true;
 388     }
 389   }
 390
 391   // Add the declaration to the end.
 392   IDI->AddDecl(D);
 393   return true;
 394 }
 395
 396 void IdentifierResolver::readingIdentifier(IdentifierInfo &II) {
 397   if (II.isOutOfDate())
 398     PP.getExternalSource()->updateOutOfDateIdentifier(II);
 399 }
 400
 401 void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) {
 402   if (II.isOutOfDate())
 403     PP.getExternalSource()->updateOutOfDateIdentifier(II);
 404
 405   if (II.isFromAST())
 406     II.setChangedSinceDeserialization();
 407 }
 408
 409 //===----------------------------------------------------------------------===//
 410 // IdDeclInfoMap Implementation
 411 //===----------------------------------------------------------------------===//
 412
 413 /// Returns the IdDeclInfo associated to the DeclarationName.
 414 /// It creates a new IdDeclInfo if one was not created before for this id.
 415 IdentifierResolver::IdDeclInfo &
 416 IdentifierResolver::IdDeclInfoMap::operator[](DeclarationName Name) {
 417   void *Ptr = Name.getFETokenInfo<void>();
 418
 419   if (Ptr) return *toIdDeclInfo(Ptr);
 420
 421   if (CurIndex == POOL_SIZE) {
 422     CurPool = new IdDeclInfoPool(CurPool);
 423     CurIndex = 0;
 424   }
 425   IdDeclInfo *IDI = &CurPool->Pool[CurIndex];
 426   Name.setFETokenInfo(reinterpret_cast<void*>(
 427                               reinterpret_cast<uintptr_t>(IDI) | 0x1)
 428                                                                      );
 429   ++CurIndex;
 430   return *IDI;
 431 }
 432
 433 void IdentifierResolver::iterator::incrementSlowCase() {
 434   NamedDecl *D = **this;
 435   void *InfoPtr = D->getDeclName().getFETokenInfo<void>();
 436   assert(!isDeclPtr(InfoPtr) && "Decl with wrong id ?");
 437   IdDeclInfo *Info = toIdDeclInfo(InfoPtr);
 438
 439   BaseIter I = getIterator();
 440   if (I != Info->decls_begin())
 441     *this = iterator(I-1);
 442   else // No more decls.
 443     *this = iterator();
 444 }