SemaLookup.cpp revision 3eb207002be2bdffddc850aafd21a0a5710ca1c7
1//===--------------------- SemaLookup.cpp - Name Lookup ------------------===// 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 name lookup for C, C++, Objective-C, and 11// Objective-C++. 12// 13//===----------------------------------------------------------------------===// 14#include "Sema.h" 15#include "SemaInherit.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/Decl.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/DeclObjC.h" 20#include "clang/AST/DeclTemplate.h" 21#include "clang/AST/Expr.h" 22#include "clang/Parse/DeclSpec.h" 23#include "clang/Basic/LangOptions.h" 24#include "llvm/ADT/STLExtras.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include <set> 27#include <vector> 28#include <iterator> 29#include <utility> 30#include <algorithm> 31 32using namespace clang; 33 34typedef llvm::SmallVector<UsingDirectiveDecl*, 4> UsingDirectivesTy; 35typedef llvm::DenseSet<NamespaceDecl*> NamespaceSet; 36typedef llvm::SmallVector<Sema::LookupResult, 3> LookupResultsTy; 37 38/// UsingDirAncestorCompare - Implements strict weak ordering of 39/// UsingDirectives. It orders them by address of its common ancestor. 40struct UsingDirAncestorCompare { 41 42 /// @brief Compares UsingDirectiveDecl common ancestor with DeclContext. 43 bool operator () (UsingDirectiveDecl *U, const DeclContext *Ctx) const { 44 return U->getCommonAncestor() < Ctx; 45 } 46 47 /// @brief Compares UsingDirectiveDecl common ancestor with DeclContext. 48 bool operator () (const DeclContext *Ctx, UsingDirectiveDecl *U) const { 49 return Ctx < U->getCommonAncestor(); 50 } 51 52 /// @brief Compares UsingDirectiveDecl common ancestors. 53 bool operator () (UsingDirectiveDecl *U1, UsingDirectiveDecl *U2) const { 54 return U1->getCommonAncestor() < U2->getCommonAncestor(); 55 } 56}; 57 58/// AddNamespaceUsingDirectives - Adds all UsingDirectiveDecl's to heap UDirs 59/// (ordered by common ancestors), found in namespace NS, 60/// including all found (recursively) in their nominated namespaces. 61void AddNamespaceUsingDirectives(ASTContext &Context, 62 DeclContext *NS, 63 UsingDirectivesTy &UDirs, 64 NamespaceSet &Visited) { 65 DeclContext::udir_iterator I, End; 66 67 for (llvm::tie(I, End) = NS->getUsingDirectives(Context); I !=End; ++I) { 68 UDirs.push_back(*I); 69 std::push_heap(UDirs.begin(), UDirs.end(), UsingDirAncestorCompare()); 70 NamespaceDecl *Nominated = (*I)->getNominatedNamespace(); 71 if (Visited.insert(Nominated).second) 72 AddNamespaceUsingDirectives(Context, Nominated, UDirs, /*ref*/ Visited); 73 } 74} 75 76/// AddScopeUsingDirectives - Adds all UsingDirectiveDecl's found in Scope S, 77/// including all found in the namespaces they nominate. 78static void AddScopeUsingDirectives(ASTContext &Context, Scope *S, 79 UsingDirectivesTy &UDirs) { 80 NamespaceSet VisitedNS; 81 82 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) { 83 84 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(Ctx)) 85 VisitedNS.insert(NS); 86 87 AddNamespaceUsingDirectives(Context, Ctx, UDirs, /*ref*/ VisitedNS); 88 89 } else { 90 Scope::udir_iterator I = S->using_directives_begin(), 91 End = S->using_directives_end(); 92 93 for (; I != End; ++I) { 94 UsingDirectiveDecl *UD = I->getAs<UsingDirectiveDecl>(); 95 UDirs.push_back(UD); 96 std::push_heap(UDirs.begin(), UDirs.end(), UsingDirAncestorCompare()); 97 98 NamespaceDecl *Nominated = UD->getNominatedNamespace(); 99 if (!VisitedNS.count(Nominated)) { 100 VisitedNS.insert(Nominated); 101 AddNamespaceUsingDirectives(Context, Nominated, UDirs, 102 /*ref*/ VisitedNS); 103 } 104 } 105 } 106} 107 108/// MaybeConstructOverloadSet - Name lookup has determined that the 109/// elements in [I, IEnd) have the name that we are looking for, and 110/// *I is a match for the namespace. This routine returns an 111/// appropriate Decl for name lookup, which may either be *I or an 112/// OverloadedFunctionDecl that represents the overloaded functions in 113/// [I, IEnd). 114/// 115/// The existance of this routine is temporary; users of LookupResult 116/// should be able to handle multiple results, to deal with cases of 117/// ambiguity and overloaded functions without needing to create a 118/// Decl node. 119template<typename DeclIterator> 120static NamedDecl * 121MaybeConstructOverloadSet(ASTContext &Context, 122 DeclIterator I, DeclIterator IEnd) { 123 assert(I != IEnd && "Iterator range cannot be empty"); 124 assert(!isa<OverloadedFunctionDecl>(*I) && 125 "Cannot have an overloaded function"); 126 127 if (isa<FunctionDecl>(*I)) { 128 // If we found a function, there might be more functions. If 129 // so, collect them into an overload set. 130 DeclIterator Last = I; 131 OverloadedFunctionDecl *Ovl = 0; 132 for (++Last; Last != IEnd && isa<FunctionDecl>(*Last); ++Last) { 133 if (!Ovl) { 134 // FIXME: We leak this overload set. Eventually, we want to 135 // stop building the declarations for these overload sets, so 136 // there will be nothing to leak. 137 Ovl = OverloadedFunctionDecl::Create(Context, (*I)->getDeclContext(), 138 (*I)->getDeclName()); 139 Ovl->addOverload(cast<FunctionDecl>(*I)); 140 } 141 Ovl->addOverload(cast<FunctionDecl>(*Last)); 142 } 143 144 // If we had more than one function, we built an overload 145 // set. Return it. 146 if (Ovl) 147 return Ovl; 148 } 149 150 return *I; 151} 152 153/// Merges together multiple LookupResults dealing with duplicated Decl's. 154static Sema::LookupResult 155MergeLookupResults(ASTContext &Context, LookupResultsTy &Results) { 156 typedef Sema::LookupResult LResult; 157 typedef llvm::SmallPtrSet<NamedDecl*, 4> DeclsSetTy; 158 159 // Remove duplicated Decl pointing at same Decl, by storing them in 160 // associative collection. This might be case for code like: 161 // 162 // namespace A { int i; } 163 // namespace B { using namespace A; } 164 // namespace C { using namespace A; } 165 // 166 // void foo() { 167 // using namespace B; 168 // using namespace C; 169 // ++i; // finds A::i, from both namespace B and C at global scope 170 // } 171 // 172 // C++ [namespace.qual].p3: 173 // The same declaration found more than once is not an ambiguity 174 // (because it is still a unique declaration). 175 DeclsSetTy FoundDecls; 176 177 // Counter of tag names, and functions for resolving ambiguity 178 // and name hiding. 179 std::size_t TagNames = 0, Functions = 0, OrdinaryNonFunc = 0; 180 181 LookupResultsTy::iterator I = Results.begin(), End = Results.end(); 182 183 // No name lookup results, return early. 184 if (I == End) return LResult::CreateLookupResult(Context, 0); 185 186 // Keep track of the tag declaration we found. We only use this if 187 // we find a single tag declaration. 188 TagDecl *TagFound = 0; 189 190 for (; I != End; ++I) { 191 switch (I->getKind()) { 192 case LResult::NotFound: 193 assert(false && 194 "Should be always successful name lookup result here."); 195 break; 196 197 case LResult::AmbiguousReference: 198 case LResult::AmbiguousBaseSubobjectTypes: 199 case LResult::AmbiguousBaseSubobjects: 200 assert(false && "Shouldn't get ambiguous lookup here."); 201 break; 202 203 case LResult::Found: { 204 NamedDecl *ND = I->getAsDecl(); 205 if (TagDecl *TD = dyn_cast<TagDecl>(ND)) { 206 TagFound = Context.getCanonicalDecl(TD); 207 TagNames += FoundDecls.insert(TagFound)? 1 : 0; 208 } else if (isa<FunctionDecl>(ND)) 209 Functions += FoundDecls.insert(ND)? 1 : 0; 210 else 211 FoundDecls.insert(ND); 212 break; 213 } 214 215 case LResult::FoundOverloaded: 216 for (LResult::iterator FI = I->begin(), FEnd = I->end(); FI != FEnd; ++FI) 217 Functions += FoundDecls.insert(*FI)? 1 : 0; 218 break; 219 } 220 } 221 OrdinaryNonFunc = FoundDecls.size() - TagNames - Functions; 222 bool Ambiguous = false, NameHidesTags = false; 223 224 if (FoundDecls.size() == 1) { 225 // 1) Exactly one result. 226 } else if (TagNames > 1) { 227 // 2) Multiple tag names (even though they may be hidden by an 228 // object name). 229 Ambiguous = true; 230 } else if (FoundDecls.size() - TagNames == 1) { 231 // 3) Ordinary name hides (optional) tag. 232 NameHidesTags = TagFound; 233 } else if (Functions) { 234 // C++ [basic.lookup].p1: 235 // ... Name lookup may associate more than one declaration with 236 // a name if it finds the name to be a function name; the declarations 237 // are said to form a set of overloaded functions (13.1). 238 // Overload resolution (13.3) takes place after name lookup has succeeded. 239 // 240 if (!OrdinaryNonFunc) { 241 // 4) Functions hide tag names. 242 NameHidesTags = TagFound; 243 } else { 244 // 5) Functions + ordinary names. 245 Ambiguous = true; 246 } 247 } else { 248 // 6) Multiple non-tag names 249 Ambiguous = true; 250 } 251 252 if (Ambiguous) 253 return LResult::CreateLookupResult(Context, 254 FoundDecls.begin(), FoundDecls.size()); 255 if (NameHidesTags) { 256 // There's only one tag, TagFound. Remove it. 257 assert(TagFound && FoundDecls.count(TagFound) && "No tag name found?"); 258 FoundDecls.erase(TagFound); 259 } 260 261 // Return successful name lookup result. 262 return LResult::CreateLookupResult(Context, 263 MaybeConstructOverloadSet(Context, 264 FoundDecls.begin(), 265 FoundDecls.end())); 266} 267 268// Retrieve the set of identifier namespaces that correspond to a 269// specific kind of name lookup. 270inline unsigned 271getIdentifierNamespacesFromLookupNameKind(Sema::LookupNameKind NameKind, 272 bool CPlusPlus) { 273 unsigned IDNS = 0; 274 switch (NameKind) { 275 case Sema::LookupOrdinaryName: 276 case Sema::LookupOperatorName: 277 case Sema::LookupRedeclarationWithLinkage: 278 IDNS = Decl::IDNS_Ordinary; 279 if (CPlusPlus) 280 IDNS |= Decl::IDNS_Tag | Decl::IDNS_Member; 281 break; 282 283 case Sema::LookupTagName: 284 IDNS = Decl::IDNS_Tag; 285 break; 286 287 case Sema::LookupMemberName: 288 IDNS = Decl::IDNS_Member; 289 if (CPlusPlus) 290 IDNS |= Decl::IDNS_Tag | Decl::IDNS_Ordinary; 291 break; 292 293 case Sema::LookupNestedNameSpecifierName: 294 case Sema::LookupNamespaceName: 295 IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Member; 296 break; 297 298 case Sema::LookupObjCProtocolName: 299 IDNS = Decl::IDNS_ObjCProtocol; 300 break; 301 302 case Sema::LookupObjCImplementationName: 303 IDNS = Decl::IDNS_ObjCImplementation; 304 break; 305 306 case Sema::LookupObjCCategoryImplName: 307 IDNS = Decl::IDNS_ObjCCategoryImpl; 308 break; 309 } 310 return IDNS; 311} 312 313Sema::LookupResult 314Sema::LookupResult::CreateLookupResult(ASTContext &Context, NamedDecl *D) { 315 if (ObjCCompatibleAliasDecl *Alias 316 = dyn_cast_or_null<ObjCCompatibleAliasDecl>(D)) 317 D = Alias->getClassInterface(); 318 319 LookupResult Result; 320 Result.StoredKind = (D && isa<OverloadedFunctionDecl>(D))? 321 OverloadedDeclSingleDecl : SingleDecl; 322 Result.First = reinterpret_cast<uintptr_t>(D); 323 Result.Last = 0; 324 Result.Context = &Context; 325 return Result; 326} 327 328/// @brief Moves the name-lookup results from Other to this LookupResult. 329Sema::LookupResult 330Sema::LookupResult::CreateLookupResult(ASTContext &Context, 331 IdentifierResolver::iterator F, 332 IdentifierResolver::iterator L) { 333 LookupResult Result; 334 Result.Context = &Context; 335 336 if (F != L && isa<FunctionDecl>(*F)) { 337 IdentifierResolver::iterator Next = F; 338 ++Next; 339 if (Next != L && isa<FunctionDecl>(*Next)) { 340 Result.StoredKind = OverloadedDeclFromIdResolver; 341 Result.First = F.getAsOpaqueValue(); 342 Result.Last = L.getAsOpaqueValue(); 343 return Result; 344 } 345 } 346 347 Decl *D = *F; 348 if (ObjCCompatibleAliasDecl *Alias 349 = dyn_cast_or_null<ObjCCompatibleAliasDecl>(D)) 350 D = Alias->getClassInterface(); 351 352 Result.StoredKind = SingleDecl; 353 Result.First = reinterpret_cast<uintptr_t>(D); 354 Result.Last = 0; 355 return Result; 356} 357 358Sema::LookupResult 359Sema::LookupResult::CreateLookupResult(ASTContext &Context, 360 DeclContext::lookup_iterator F, 361 DeclContext::lookup_iterator L) { 362 LookupResult Result; 363 Result.Context = &Context; 364 365 if (F != L && isa<FunctionDecl>(*F)) { 366 DeclContext::lookup_iterator Next = F; 367 ++Next; 368 if (Next != L && isa<FunctionDecl>(*Next)) { 369 Result.StoredKind = OverloadedDeclFromDeclContext; 370 Result.First = reinterpret_cast<uintptr_t>(F); 371 Result.Last = reinterpret_cast<uintptr_t>(L); 372 return Result; 373 } 374 } 375 376 Decl *D = *F; 377 if (ObjCCompatibleAliasDecl *Alias 378 = dyn_cast_or_null<ObjCCompatibleAliasDecl>(D)) 379 D = Alias->getClassInterface(); 380 381 Result.StoredKind = SingleDecl; 382 Result.First = reinterpret_cast<uintptr_t>(D); 383 Result.Last = 0; 384 return Result; 385} 386 387/// @brief Determine the result of name lookup. 388Sema::LookupResult::LookupKind Sema::LookupResult::getKind() const { 389 switch (StoredKind) { 390 case SingleDecl: 391 return (reinterpret_cast<Decl *>(First) != 0)? Found : NotFound; 392 393 case OverloadedDeclSingleDecl: 394 case OverloadedDeclFromIdResolver: 395 case OverloadedDeclFromDeclContext: 396 return FoundOverloaded; 397 398 case AmbiguousLookupStoresBasePaths: 399 return Last? AmbiguousBaseSubobjectTypes : AmbiguousBaseSubobjects; 400 401 case AmbiguousLookupStoresDecls: 402 return AmbiguousReference; 403 } 404 405 // We can't ever get here. 406 return NotFound; 407} 408 409/// @brief Converts the result of name lookup into a single (possible 410/// NULL) pointer to a declaration. 411/// 412/// The resulting declaration will either be the declaration we found 413/// (if only a single declaration was found), an 414/// OverloadedFunctionDecl (if an overloaded function was found), or 415/// NULL (if no declaration was found). This conversion must not be 416/// used anywhere where name lookup could result in an ambiguity. 417/// 418/// The OverloadedFunctionDecl conversion is meant as a stop-gap 419/// solution, since it causes the OverloadedFunctionDecl to be 420/// leaked. FIXME: Eventually, there will be a better way to iterate 421/// over the set of overloaded functions returned by name lookup. 422NamedDecl *Sema::LookupResult::getAsDecl() const { 423 switch (StoredKind) { 424 case SingleDecl: 425 return reinterpret_cast<NamedDecl *>(First); 426 427 case OverloadedDeclFromIdResolver: 428 return MaybeConstructOverloadSet(*Context, 429 IdentifierResolver::iterator::getFromOpaqueValue(First), 430 IdentifierResolver::iterator::getFromOpaqueValue(Last)); 431 432 case OverloadedDeclFromDeclContext: 433 return MaybeConstructOverloadSet(*Context, 434 reinterpret_cast<DeclContext::lookup_iterator>(First), 435 reinterpret_cast<DeclContext::lookup_iterator>(Last)); 436 437 case OverloadedDeclSingleDecl: 438 return reinterpret_cast<OverloadedFunctionDecl*>(First); 439 440 case AmbiguousLookupStoresDecls: 441 case AmbiguousLookupStoresBasePaths: 442 assert(false && 443 "Name lookup returned an ambiguity that could not be handled"); 444 break; 445 } 446 447 return 0; 448} 449 450/// @brief Retrieves the BasePaths structure describing an ambiguous 451/// name lookup, or null. 452BasePaths *Sema::LookupResult::getBasePaths() const { 453 if (StoredKind == AmbiguousLookupStoresBasePaths) 454 return reinterpret_cast<BasePaths *>(First); 455 return 0; 456} 457 458Sema::LookupResult::iterator::reference 459Sema::LookupResult::iterator::operator*() const { 460 switch (Result->StoredKind) { 461 case SingleDecl: 462 return reinterpret_cast<NamedDecl*>(Current); 463 464 case OverloadedDeclSingleDecl: 465 return *reinterpret_cast<NamedDecl**>(Current); 466 467 case OverloadedDeclFromIdResolver: 468 return *IdentifierResolver::iterator::getFromOpaqueValue(Current); 469 470 case AmbiguousLookupStoresBasePaths: 471 if (Result->Last) 472 return *reinterpret_cast<NamedDecl**>(Current); 473 474 // Fall through to handle the DeclContext::lookup_iterator we're 475 // storing. 476 477 case OverloadedDeclFromDeclContext: 478 case AmbiguousLookupStoresDecls: 479 return *reinterpret_cast<DeclContext::lookup_iterator>(Current); 480 } 481 482 return 0; 483} 484 485Sema::LookupResult::iterator& Sema::LookupResult::iterator::operator++() { 486 switch (Result->StoredKind) { 487 case SingleDecl: 488 Current = reinterpret_cast<uintptr_t>((NamedDecl*)0); 489 break; 490 491 case OverloadedDeclSingleDecl: { 492 NamedDecl ** I = reinterpret_cast<NamedDecl**>(Current); 493 ++I; 494 Current = reinterpret_cast<uintptr_t>(I); 495 break; 496 } 497 498 case OverloadedDeclFromIdResolver: { 499 IdentifierResolver::iterator I 500 = IdentifierResolver::iterator::getFromOpaqueValue(Current); 501 ++I; 502 Current = I.getAsOpaqueValue(); 503 break; 504 } 505 506 case AmbiguousLookupStoresBasePaths: 507 if (Result->Last) { 508 NamedDecl ** I = reinterpret_cast<NamedDecl**>(Current); 509 ++I; 510 Current = reinterpret_cast<uintptr_t>(I); 511 break; 512 } 513 // Fall through to handle the DeclContext::lookup_iterator we're 514 // storing. 515 516 case OverloadedDeclFromDeclContext: 517 case AmbiguousLookupStoresDecls: { 518 DeclContext::lookup_iterator I 519 = reinterpret_cast<DeclContext::lookup_iterator>(Current); 520 ++I; 521 Current = reinterpret_cast<uintptr_t>(I); 522 break; 523 } 524 } 525 526 return *this; 527} 528 529Sema::LookupResult::iterator Sema::LookupResult::begin() { 530 switch (StoredKind) { 531 case SingleDecl: 532 case OverloadedDeclFromIdResolver: 533 case OverloadedDeclFromDeclContext: 534 case AmbiguousLookupStoresDecls: 535 return iterator(this, First); 536 537 case OverloadedDeclSingleDecl: { 538 OverloadedFunctionDecl * Ovl = 539 reinterpret_cast<OverloadedFunctionDecl*>(First); 540 return iterator(this, 541 reinterpret_cast<uintptr_t>(&(*Ovl->function_begin()))); 542 } 543 544 case AmbiguousLookupStoresBasePaths: 545 if (Last) 546 return iterator(this, 547 reinterpret_cast<uintptr_t>(getBasePaths()->found_decls_begin())); 548 else 549 return iterator(this, 550 reinterpret_cast<uintptr_t>(getBasePaths()->front().Decls.first)); 551 } 552 553 // Required to suppress GCC warning. 554 return iterator(); 555} 556 557Sema::LookupResult::iterator Sema::LookupResult::end() { 558 switch (StoredKind) { 559 case SingleDecl: 560 case OverloadedDeclFromIdResolver: 561 case OverloadedDeclFromDeclContext: 562 case AmbiguousLookupStoresDecls: 563 return iterator(this, Last); 564 565 case OverloadedDeclSingleDecl: { 566 OverloadedFunctionDecl * Ovl = 567 reinterpret_cast<OverloadedFunctionDecl*>(First); 568 return iterator(this, 569 reinterpret_cast<uintptr_t>(&(*Ovl->function_end()))); 570 } 571 572 case AmbiguousLookupStoresBasePaths: 573 if (Last) 574 return iterator(this, 575 reinterpret_cast<uintptr_t>(getBasePaths()->found_decls_end())); 576 else 577 return iterator(this, reinterpret_cast<uintptr_t>( 578 getBasePaths()->front().Decls.second)); 579 } 580 581 // Required to suppress GCC warning. 582 return iterator(); 583} 584 585void Sema::LookupResult::Destroy() { 586 if (BasePaths *Paths = getBasePaths()) 587 delete Paths; 588 else if (getKind() == AmbiguousReference) 589 delete[] reinterpret_cast<NamedDecl **>(First); 590} 591 592static void 593CppNamespaceLookup(ASTContext &Context, DeclContext *NS, 594 DeclarationName Name, Sema::LookupNameKind NameKind, 595 unsigned IDNS, LookupResultsTy &Results, 596 UsingDirectivesTy *UDirs = 0) { 597 598 assert(NS && NS->isFileContext() && "CppNamespaceLookup() requires namespace!"); 599 600 // Perform qualified name lookup into the LookupCtx. 601 DeclContext::lookup_iterator I, E; 602 for (llvm::tie(I, E) = NS->lookup(Context, Name); I != E; ++I) 603 if (Sema::isAcceptableLookupResult(*I, NameKind, IDNS)) { 604 Results.push_back(Sema::LookupResult::CreateLookupResult(Context, I, E)); 605 break; 606 } 607 608 if (UDirs) { 609 // For each UsingDirectiveDecl, which common ancestor is equal 610 // to NS, we preform qualified name lookup into namespace nominated by it. 611 UsingDirectivesTy::const_iterator UI, UEnd; 612 llvm::tie(UI, UEnd) = 613 std::equal_range(UDirs->begin(), UDirs->end(), NS, 614 UsingDirAncestorCompare()); 615 616 for (; UI != UEnd; ++UI) 617 CppNamespaceLookup(Context, (*UI)->getNominatedNamespace(), 618 Name, NameKind, IDNS, Results); 619 } 620} 621 622static bool isNamespaceOrTranslationUnitScope(Scope *S) { 623 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) 624 return Ctx->isFileContext(); 625 return false; 626} 627 628std::pair<bool, Sema::LookupResult> 629Sema::CppLookupName(Scope *S, DeclarationName Name, 630 LookupNameKind NameKind, bool RedeclarationOnly) { 631 assert(getLangOptions().CPlusPlus && 632 "Can perform only C++ lookup"); 633 unsigned IDNS 634 = getIdentifierNamespacesFromLookupNameKind(NameKind, /*CPlusPlus*/ true); 635 Scope *Initial = S; 636 DeclContext *OutOfLineCtx = 0; 637 IdentifierResolver::iterator 638 I = IdResolver.begin(Name), 639 IEnd = IdResolver.end(); 640 641 // First we lookup local scope. 642 // We don't consider using-directives, as per 7.3.4.p1 [namespace.udir] 643 // ...During unqualified name lookup (3.4.1), the names appear as if 644 // they were declared in the nearest enclosing namespace which contains 645 // both the using-directive and the nominated namespace. 646 // [Note: in this context, “contains” means “contains directly or 647 // indirectly”. 648 // 649 // For example: 650 // namespace A { int i; } 651 // void foo() { 652 // int i; 653 // { 654 // using namespace A; 655 // ++i; // finds local 'i', A::i appears at global scope 656 // } 657 // } 658 // 659 for (; S && !isNamespaceOrTranslationUnitScope(S); S = S->getParent()) { 660 // Check whether the IdResolver has anything in this scope. 661 for (; I != IEnd && S->isDeclScope(DeclPtrTy::make(*I)); ++I) { 662 if (isAcceptableLookupResult(*I, NameKind, IDNS)) { 663 // We found something. Look for anything else in our scope 664 // with this same name and in an acceptable identifier 665 // namespace, so that we can construct an overload set if we 666 // need to. 667 IdentifierResolver::iterator LastI = I; 668 for (++LastI; LastI != IEnd; ++LastI) { 669 if (!S->isDeclScope(DeclPtrTy::make(*LastI))) 670 break; 671 } 672 LookupResult Result = 673 LookupResult::CreateLookupResult(Context, I, LastI); 674 return std::make_pair(true, Result); 675 } 676 } 677 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) { 678 LookupResult R; 679 // Perform member lookup into struct. 680 // FIXME: In some cases, we know that every name that could be 681 // found by this qualified name lookup will also be on the 682 // identifier chain. For example, inside a class without any 683 // base classes, we never need to perform qualified lookup 684 // because all of the members are on top of the identifier 685 // chain. 686 if (isa<RecordDecl>(Ctx)) { 687 R = LookupQualifiedName(Ctx, Name, NameKind, RedeclarationOnly); 688 if (R || RedeclarationOnly) 689 return std::make_pair(true, R); 690 } 691 if (Ctx->getParent() != Ctx->getLexicalParent()) { 692 // It is out of line defined C++ method or struct, we continue 693 // doing name lookup in parent context. Once we will find namespace 694 // or translation-unit we save it for possible checking 695 // using-directives later. 696 for (OutOfLineCtx = Ctx; OutOfLineCtx && !OutOfLineCtx->isFileContext(); 697 OutOfLineCtx = OutOfLineCtx->getParent()) { 698 R = LookupQualifiedName(OutOfLineCtx, Name, NameKind, RedeclarationOnly); 699 if (R || RedeclarationOnly) 700 return std::make_pair(true, R); 701 } 702 } 703 } 704 } 705 706 // Collect UsingDirectiveDecls in all scopes, and recursively all 707 // nominated namespaces by those using-directives. 708 // UsingDirectives are pushed to heap, in common ancestor pointer 709 // value order. 710 // FIXME: Cache this sorted list in Scope structure, and DeclContext, 711 // so we don't build it for each lookup! 712 UsingDirectivesTy UDirs; 713 for (Scope *SC = Initial; SC; SC = SC->getParent()) 714 if (SC->getFlags() & Scope::DeclScope) 715 AddScopeUsingDirectives(Context, SC, UDirs); 716 717 // Sort heapified UsingDirectiveDecls. 718 std::sort_heap(UDirs.begin(), UDirs.end()); 719 720 // Lookup namespace scope, and global scope. 721 // Unqualified name lookup in C++ requires looking into scopes 722 // that aren't strictly lexical, and therefore we walk through the 723 // context as well as walking through the scopes. 724 725 LookupResultsTy LookupResults; 726 assert((!OutOfLineCtx || OutOfLineCtx->isFileContext()) && 727 "We should have been looking only at file context here already."); 728 bool LookedInCtx = false; 729 LookupResult Result; 730 while (OutOfLineCtx && 731 OutOfLineCtx != S->getEntity() && 732 OutOfLineCtx->isNamespace()) { 733 LookedInCtx = true; 734 735 // Look into context considering using-directives. 736 CppNamespaceLookup(Context, OutOfLineCtx, Name, NameKind, IDNS, 737 LookupResults, &UDirs); 738 739 if ((Result = MergeLookupResults(Context, LookupResults)) || 740 (RedeclarationOnly && !OutOfLineCtx->isTransparentContext())) 741 return std::make_pair(true, Result); 742 743 OutOfLineCtx = OutOfLineCtx->getParent(); 744 } 745 746 for (; S; S = S->getParent()) { 747 DeclContext *Ctx = static_cast<DeclContext *>(S->getEntity()); 748 assert(Ctx && Ctx->isFileContext() && 749 "We should have been looking only at file context here already."); 750 751 // Check whether the IdResolver has anything in this scope. 752 for (; I != IEnd && S->isDeclScope(DeclPtrTy::make(*I)); ++I) { 753 if (isAcceptableLookupResult(*I, NameKind, IDNS)) { 754 // We found something. Look for anything else in our scope 755 // with this same name and in an acceptable identifier 756 // namespace, so that we can construct an overload set if we 757 // need to. 758 IdentifierResolver::iterator LastI = I; 759 for (++LastI; LastI != IEnd; ++LastI) { 760 if (!S->isDeclScope(DeclPtrTy::make(*LastI))) 761 break; 762 } 763 764 // We store name lookup result, and continue trying to look into 765 // associated context, and maybe namespaces nominated by 766 // using-directives. 767 LookupResults.push_back( 768 LookupResult::CreateLookupResult(Context, I, LastI)); 769 break; 770 } 771 } 772 773 LookedInCtx = true; 774 // Look into context considering using-directives. 775 CppNamespaceLookup(Context, Ctx, Name, NameKind, IDNS, 776 LookupResults, &UDirs); 777 778 if ((Result = MergeLookupResults(Context, LookupResults)) || 779 (RedeclarationOnly && !Ctx->isTransparentContext())) 780 return std::make_pair(true, Result); 781 } 782 783 if (!(LookedInCtx || LookupResults.empty())) { 784 // We didn't Performed lookup in Scope entity, so we return 785 // result form IdentifierResolver. 786 assert((LookupResults.size() == 1) && "Wrong size!"); 787 return std::make_pair(true, LookupResults.front()); 788 } 789 return std::make_pair(false, LookupResult()); 790} 791 792/// @brief Perform unqualified name lookup starting from a given 793/// scope. 794/// 795/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is 796/// used to find names within the current scope. For example, 'x' in 797/// @code 798/// int x; 799/// int f() { 800/// return x; // unqualified name look finds 'x' in the global scope 801/// } 802/// @endcode 803/// 804/// Different lookup criteria can find different names. For example, a 805/// particular scope can have both a struct and a function of the same 806/// name, and each can be found by certain lookup criteria. For more 807/// information about lookup criteria, see the documentation for the 808/// class LookupCriteria. 809/// 810/// @param S The scope from which unqualified name lookup will 811/// begin. If the lookup criteria permits, name lookup may also search 812/// in the parent scopes. 813/// 814/// @param Name The name of the entity that we are searching for. 815/// 816/// @param Loc If provided, the source location where we're performing 817/// name lookup. At present, this is only used to produce diagnostics when 818/// C library functions (like "malloc") are implicitly declared. 819/// 820/// @returns The result of name lookup, which includes zero or more 821/// declarations and possibly additional information used to diagnose 822/// ambiguities. 823Sema::LookupResult 824Sema::LookupName(Scope *S, DeclarationName Name, LookupNameKind NameKind, 825 bool RedeclarationOnly, bool AllowBuiltinCreation, 826 SourceLocation Loc) { 827 if (!Name) return LookupResult::CreateLookupResult(Context, 0); 828 829 if (!getLangOptions().CPlusPlus) { 830 // Unqualified name lookup in C/Objective-C is purely lexical, so 831 // search in the declarations attached to the name. 832 unsigned IDNS = 0; 833 switch (NameKind) { 834 case Sema::LookupOrdinaryName: 835 IDNS = Decl::IDNS_Ordinary; 836 break; 837 838 case Sema::LookupTagName: 839 IDNS = Decl::IDNS_Tag; 840 break; 841 842 case Sema::LookupMemberName: 843 IDNS = Decl::IDNS_Member; 844 break; 845 846 case Sema::LookupOperatorName: 847 case Sema::LookupNestedNameSpecifierName: 848 case Sema::LookupNamespaceName: 849 assert(false && "C does not perform these kinds of name lookup"); 850 break; 851 852 case Sema::LookupRedeclarationWithLinkage: 853 // Find the nearest non-transparent declaration scope. 854 while (!(S->getFlags() & Scope::DeclScope) || 855 (S->getEntity() && 856 static_cast<DeclContext *>(S->getEntity()) 857 ->isTransparentContext())) 858 S = S->getParent(); 859 IDNS = Decl::IDNS_Ordinary; 860 break; 861 862 case Sema::LookupObjCProtocolName: 863 IDNS = Decl::IDNS_ObjCProtocol; 864 break; 865 866 case Sema::LookupObjCImplementationName: 867 IDNS = Decl::IDNS_ObjCImplementation; 868 break; 869 870 case Sema::LookupObjCCategoryImplName: 871 IDNS = Decl::IDNS_ObjCCategoryImpl; 872 break; 873 } 874 875 // Scan up the scope chain looking for a decl that matches this 876 // identifier that is in the appropriate namespace. This search 877 // should not take long, as shadowing of names is uncommon, and 878 // deep shadowing is extremely uncommon. 879 bool LeftStartingScope = false; 880 881 for (IdentifierResolver::iterator I = IdResolver.begin(Name), 882 IEnd = IdResolver.end(); 883 I != IEnd; ++I) 884 if ((*I)->isInIdentifierNamespace(IDNS)) { 885 if (NameKind == LookupRedeclarationWithLinkage) { 886 // Determine whether this (or a previous) declaration is 887 // out-of-scope. 888 if (!LeftStartingScope && !S->isDeclScope(DeclPtrTy::make(*I))) 889 LeftStartingScope = true; 890 891 // If we found something outside of our starting scope that 892 // does not have linkage, skip it. 893 if (LeftStartingScope && !((*I)->hasLinkage())) 894 continue; 895 } 896 897 if ((*I)->getAttr<OverloadableAttr>()) { 898 // If this declaration has the "overloadable" attribute, we 899 // might have a set of overloaded functions. 900 901 // Figure out what scope the identifier is in. 902 while (!(S->getFlags() & Scope::DeclScope) || 903 !S->isDeclScope(DeclPtrTy::make(*I))) 904 S = S->getParent(); 905 906 // Find the last declaration in this scope (with the same 907 // name, naturally). 908 IdentifierResolver::iterator LastI = I; 909 for (++LastI; LastI != IEnd; ++LastI) { 910 if (!S->isDeclScope(DeclPtrTy::make(*LastI))) 911 break; 912 } 913 914 return LookupResult::CreateLookupResult(Context, I, LastI); 915 } 916 917 // We have a single lookup result. 918 return LookupResult::CreateLookupResult(Context, *I); 919 } 920 } else { 921 // Perform C++ unqualified name lookup. 922 std::pair<bool, LookupResult> MaybeResult = 923 CppLookupName(S, Name, NameKind, RedeclarationOnly); 924 if (MaybeResult.first) 925 return MaybeResult.second; 926 } 927 928 // If we didn't find a use of this identifier, and if the identifier 929 // corresponds to a compiler builtin, create the decl object for the builtin 930 // now, injecting it into translation unit scope, and return it. 931 if (NameKind == LookupOrdinaryName || 932 NameKind == LookupRedeclarationWithLinkage) { 933 IdentifierInfo *II = Name.getAsIdentifierInfo(); 934 if (II && AllowBuiltinCreation) { 935 // If this is a builtin on this (or all) targets, create the decl. 936 if (unsigned BuiltinID = II->getBuiltinID()) { 937 // In C++, we don't have any predefined library functions like 938 // 'malloc'. Instead, we'll just error. 939 if (getLangOptions().CPlusPlus && 940 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) 941 return LookupResult::CreateLookupResult(Context, 0); 942 943 return LookupResult::CreateLookupResult(Context, 944 LazilyCreateBuiltin((IdentifierInfo *)II, BuiltinID, 945 S, RedeclarationOnly, Loc)); 946 } 947 } 948 } 949 return LookupResult::CreateLookupResult(Context, 0); 950} 951 952/// @brief Perform qualified name lookup into a given context. 953/// 954/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find 955/// names when the context of those names is explicit specified, e.g., 956/// "std::vector" or "x->member". 957/// 958/// Different lookup criteria can find different names. For example, a 959/// particular scope can have both a struct and a function of the same 960/// name, and each can be found by certain lookup criteria. For more 961/// information about lookup criteria, see the documentation for the 962/// class LookupCriteria. 963/// 964/// @param LookupCtx The context in which qualified name lookup will 965/// search. If the lookup criteria permits, name lookup may also search 966/// in the parent contexts or (for C++ classes) base classes. 967/// 968/// @param Name The name of the entity that we are searching for. 969/// 970/// @param Criteria The criteria that this routine will use to 971/// determine which names are visible and which names will be 972/// found. Note that name lookup will find a name that is visible by 973/// the given criteria, but the entity itself may not be semantically 974/// correct or even the kind of entity expected based on the 975/// lookup. For example, searching for a nested-name-specifier name 976/// might result in an EnumDecl, which is visible but is not permitted 977/// as a nested-name-specifier in C++03. 978/// 979/// @returns The result of name lookup, which includes zero or more 980/// declarations and possibly additional information used to diagnose 981/// ambiguities. 982Sema::LookupResult 983Sema::LookupQualifiedName(DeclContext *LookupCtx, DeclarationName Name, 984 LookupNameKind NameKind, bool RedeclarationOnly) { 985 assert(LookupCtx && "Sema::LookupQualifiedName requires a lookup context"); 986 987 if (!Name) return LookupResult::CreateLookupResult(Context, 0); 988 989 // If we're performing qualified name lookup (e.g., lookup into a 990 // struct), find fields as part of ordinary name lookup. 991 unsigned IDNS 992 = getIdentifierNamespacesFromLookupNameKind(NameKind, 993 getLangOptions().CPlusPlus); 994 if (NameKind == LookupOrdinaryName) 995 IDNS |= Decl::IDNS_Member; 996 997 // Perform qualified name lookup into the LookupCtx. 998 DeclContext::lookup_iterator I, E; 999 for (llvm::tie(I, E) = LookupCtx->lookup(Context, Name); I != E; ++I) 1000 if (isAcceptableLookupResult(*I, NameKind, IDNS)) 1001 return LookupResult::CreateLookupResult(Context, I, E); 1002 1003 // If this isn't a C++ class or we aren't allowed to look into base 1004 // classes, we're done. 1005 if (RedeclarationOnly || !isa<CXXRecordDecl>(LookupCtx)) 1006 return LookupResult::CreateLookupResult(Context, 0); 1007 1008 // Perform lookup into our base classes. 1009 BasePaths Paths; 1010 Paths.setOrigin(Context.getTypeDeclType(cast<RecordDecl>(LookupCtx))); 1011 1012 // Look for this member in our base classes 1013 if (!LookupInBases(cast<CXXRecordDecl>(LookupCtx), 1014 MemberLookupCriteria(Name, NameKind, IDNS), Paths)) 1015 return LookupResult::CreateLookupResult(Context, 0); 1016 1017 // C++ [class.member.lookup]p2: 1018 // [...] If the resulting set of declarations are not all from 1019 // sub-objects of the same type, or the set has a nonstatic member 1020 // and includes members from distinct sub-objects, there is an 1021 // ambiguity and the program is ill-formed. Otherwise that set is 1022 // the result of the lookup. 1023 // FIXME: support using declarations! 1024 QualType SubobjectType; 1025 int SubobjectNumber = 0; 1026 for (BasePaths::paths_iterator Path = Paths.begin(), PathEnd = Paths.end(); 1027 Path != PathEnd; ++Path) { 1028 const BasePathElement &PathElement = Path->back(); 1029 1030 // Determine whether we're looking at a distinct sub-object or not. 1031 if (SubobjectType.isNull()) { 1032 // This is the first subobject we've looked at. Record it's type. 1033 SubobjectType = Context.getCanonicalType(PathElement.Base->getType()); 1034 SubobjectNumber = PathElement.SubobjectNumber; 1035 } else if (SubobjectType 1036 != Context.getCanonicalType(PathElement.Base->getType())) { 1037 // We found members of the given name in two subobjects of 1038 // different types. This lookup is ambiguous. 1039 BasePaths *PathsOnHeap = new BasePaths; 1040 PathsOnHeap->swap(Paths); 1041 return LookupResult::CreateLookupResult(Context, PathsOnHeap, true); 1042 } else if (SubobjectNumber != PathElement.SubobjectNumber) { 1043 // We have a different subobject of the same type. 1044 1045 // C++ [class.member.lookup]p5: 1046 // A static member, a nested type or an enumerator defined in 1047 // a base class T can unambiguously be found even if an object 1048 // has more than one base class subobject of type T. 1049 Decl *FirstDecl = *Path->Decls.first; 1050 if (isa<VarDecl>(FirstDecl) || 1051 isa<TypeDecl>(FirstDecl) || 1052 isa<EnumConstantDecl>(FirstDecl)) 1053 continue; 1054 1055 if (isa<CXXMethodDecl>(FirstDecl)) { 1056 // Determine whether all of the methods are static. 1057 bool AllMethodsAreStatic = true; 1058 for (DeclContext::lookup_iterator Func = Path->Decls.first; 1059 Func != Path->Decls.second; ++Func) { 1060 if (!isa<CXXMethodDecl>(*Func)) { 1061 assert(isa<TagDecl>(*Func) && "Non-function must be a tag decl"); 1062 break; 1063 } 1064 1065 if (!cast<CXXMethodDecl>(*Func)->isStatic()) { 1066 AllMethodsAreStatic = false; 1067 break; 1068 } 1069 } 1070 1071 if (AllMethodsAreStatic) 1072 continue; 1073 } 1074 1075 // We have found a nonstatic member name in multiple, distinct 1076 // subobjects. Name lookup is ambiguous. 1077 BasePaths *PathsOnHeap = new BasePaths; 1078 PathsOnHeap->swap(Paths); 1079 return LookupResult::CreateLookupResult(Context, PathsOnHeap, false); 1080 } 1081 } 1082 1083 // Lookup in a base class succeeded; return these results. 1084 1085 // If we found a function declaration, return an overload set. 1086 if (isa<FunctionDecl>(*Paths.front().Decls.first)) 1087 return LookupResult::CreateLookupResult(Context, 1088 Paths.front().Decls.first, Paths.front().Decls.second); 1089 1090 // We found a non-function declaration; return a single declaration. 1091 return LookupResult::CreateLookupResult(Context, *Paths.front().Decls.first); 1092} 1093 1094/// @brief Performs name lookup for a name that was parsed in the 1095/// source code, and may contain a C++ scope specifier. 1096/// 1097/// This routine is a convenience routine meant to be called from 1098/// contexts that receive a name and an optional C++ scope specifier 1099/// (e.g., "N::M::x"). It will then perform either qualified or 1100/// unqualified name lookup (with LookupQualifiedName or LookupName, 1101/// respectively) on the given name and return those results. 1102/// 1103/// @param S The scope from which unqualified name lookup will 1104/// begin. 1105/// 1106/// @param SS An optional C++ scope-specified, e.g., "::N::M". 1107/// 1108/// @param Name The name of the entity that name lookup will 1109/// search for. 1110/// 1111/// @param Loc If provided, the source location where we're performing 1112/// name lookup. At present, this is only used to produce diagnostics when 1113/// C library functions (like "malloc") are implicitly declared. 1114/// 1115/// @returns The result of qualified or unqualified name lookup. 1116Sema::LookupResult 1117Sema::LookupParsedName(Scope *S, const CXXScopeSpec *SS, 1118 DeclarationName Name, LookupNameKind NameKind, 1119 bool RedeclarationOnly, bool AllowBuiltinCreation, 1120 SourceLocation Loc) { 1121 if (SS && (SS->isSet() || SS->isInvalid())) { 1122 // If the scope specifier is invalid, don't even look for 1123 // anything. 1124 if (SS->isInvalid()) 1125 return LookupResult::CreateLookupResult(Context, 0); 1126 1127 assert(!isUnknownSpecialization(*SS) && "Can't lookup dependent types"); 1128 1129 if (isDependentScopeSpecifier(*SS)) { 1130 // Determine whether we are looking into the current 1131 // instantiation. 1132 NestedNameSpecifier *NNS 1133 = static_cast<NestedNameSpecifier *>(SS->getScopeRep()); 1134 CXXRecordDecl *Current = getCurrentInstantiationOf(NNS); 1135 assert(Current && "Bad dependent scope specifier"); 1136 1137 // We nested name specifier refers to the current instantiation, 1138 // so now we will look for a member of the current instantiation 1139 // (C++0x [temp.dep.type]). 1140 unsigned IDNS = getIdentifierNamespacesFromLookupNameKind(NameKind, true); 1141 DeclContext::lookup_iterator I, E; 1142 for (llvm::tie(I, E) = Current->lookup(Context, Name); I != E; ++I) 1143 if (isAcceptableLookupResult(*I, NameKind, IDNS)) 1144 return LookupResult::CreateLookupResult(Context, I, E); 1145 } 1146 1147 if (RequireCompleteDeclContext(*SS)) 1148 return LookupResult::CreateLookupResult(Context, 0); 1149 1150 return LookupQualifiedName(computeDeclContext(*SS), 1151 Name, NameKind, RedeclarationOnly); 1152 } 1153 1154 return LookupName(S, Name, NameKind, RedeclarationOnly, 1155 AllowBuiltinCreation, Loc); 1156} 1157 1158 1159/// @brief Produce a diagnostic describing the ambiguity that resulted 1160/// from name lookup. 1161/// 1162/// @param Result The ambiguous name lookup result. 1163/// 1164/// @param Name The name of the entity that name lookup was 1165/// searching for. 1166/// 1167/// @param NameLoc The location of the name within the source code. 1168/// 1169/// @param LookupRange A source range that provides more 1170/// source-location information concerning the lookup itself. For 1171/// example, this range might highlight a nested-name-specifier that 1172/// precedes the name. 1173/// 1174/// @returns true 1175bool Sema::DiagnoseAmbiguousLookup(LookupResult &Result, DeclarationName Name, 1176 SourceLocation NameLoc, 1177 SourceRange LookupRange) { 1178 assert(Result.isAmbiguous() && "Lookup result must be ambiguous"); 1179 1180 if (BasePaths *Paths = Result.getBasePaths()) { 1181 if (Result.getKind() == LookupResult::AmbiguousBaseSubobjects) { 1182 QualType SubobjectType = Paths->front().back().Base->getType(); 1183 Diag(NameLoc, diag::err_ambiguous_member_multiple_subobjects) 1184 << Name << SubobjectType << getAmbiguousPathsDisplayString(*Paths) 1185 << LookupRange; 1186 1187 DeclContext::lookup_iterator Found = Paths->front().Decls.first; 1188 while (isa<CXXMethodDecl>(*Found) && 1189 cast<CXXMethodDecl>(*Found)->isStatic()) 1190 ++Found; 1191 1192 Diag((*Found)->getLocation(), diag::note_ambiguous_member_found); 1193 1194 Result.Destroy(); 1195 return true; 1196 } 1197 1198 assert(Result.getKind() == LookupResult::AmbiguousBaseSubobjectTypes && 1199 "Unhandled form of name lookup ambiguity"); 1200 1201 Diag(NameLoc, diag::err_ambiguous_member_multiple_subobject_types) 1202 << Name << LookupRange; 1203 1204 std::set<Decl *> DeclsPrinted; 1205 for (BasePaths::paths_iterator Path = Paths->begin(), PathEnd = Paths->end(); 1206 Path != PathEnd; ++Path) { 1207 Decl *D = *Path->Decls.first; 1208 if (DeclsPrinted.insert(D).second) 1209 Diag(D->getLocation(), diag::note_ambiguous_member_found); 1210 } 1211 1212 Result.Destroy(); 1213 return true; 1214 } else if (Result.getKind() == LookupResult::AmbiguousReference) { 1215 Diag(NameLoc, diag::err_ambiguous_reference) << Name << LookupRange; 1216 1217 NamedDecl **DI = reinterpret_cast<NamedDecl **>(Result.First), 1218 **DEnd = reinterpret_cast<NamedDecl **>(Result.Last); 1219 1220 for (; DI != DEnd; ++DI) 1221 Diag((*DI)->getLocation(), diag::note_ambiguous_candidate) << *DI; 1222 1223 Result.Destroy(); 1224 return true; 1225 } 1226 1227 assert(false && "Unhandled form of name lookup ambiguity"); 1228 1229 // We can't reach here. 1230 return true; 1231} 1232 1233// \brief Add the associated classes and namespaces for 1234// argument-dependent lookup with an argument of class type 1235// (C++ [basic.lookup.koenig]p2). 1236static void 1237addAssociatedClassesAndNamespaces(CXXRecordDecl *Class, 1238 ASTContext &Context, 1239 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1240 Sema::AssociatedClassSet &AssociatedClasses) { 1241 // C++ [basic.lookup.koenig]p2: 1242 // [...] 1243 // -- If T is a class type (including unions), its associated 1244 // classes are: the class itself; the class of which it is a 1245 // member, if any; and its direct and indirect base 1246 // classes. Its associated namespaces are the namespaces in 1247 // which its associated classes are defined. 1248 1249 // Add the class of which it is a member, if any. 1250 DeclContext *Ctx = Class->getDeclContext(); 1251 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1252 AssociatedClasses.insert(EnclosingClass); 1253 1254 // Add the associated namespace for this class. 1255 while (Ctx->isRecord()) 1256 Ctx = Ctx->getParent(); 1257 if (NamespaceDecl *EnclosingNamespace = dyn_cast<NamespaceDecl>(Ctx)) 1258 AssociatedNamespaces.insert(EnclosingNamespace); 1259 1260 // Add the class itself. If we've already seen this class, we don't 1261 // need to visit base classes. 1262 if (!AssociatedClasses.insert(Class)) 1263 return; 1264 1265 // FIXME: Handle class template specializations 1266 1267 // Add direct and indirect base classes along with their associated 1268 // namespaces. 1269 llvm::SmallVector<CXXRecordDecl *, 32> Bases; 1270 Bases.push_back(Class); 1271 while (!Bases.empty()) { 1272 // Pop this class off the stack. 1273 Class = Bases.back(); 1274 Bases.pop_back(); 1275 1276 // Visit the base classes. 1277 for (CXXRecordDecl::base_class_iterator Base = Class->bases_begin(), 1278 BaseEnd = Class->bases_end(); 1279 Base != BaseEnd; ++Base) { 1280 const RecordType *BaseType = Base->getType()->getAsRecordType(); 1281 CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(BaseType->getDecl()); 1282 if (AssociatedClasses.insert(BaseDecl)) { 1283 // Find the associated namespace for this base class. 1284 DeclContext *BaseCtx = BaseDecl->getDeclContext(); 1285 while (BaseCtx->isRecord()) 1286 BaseCtx = BaseCtx->getParent(); 1287 if (NamespaceDecl *EnclosingNamespace = dyn_cast<NamespaceDecl>(BaseCtx)) 1288 AssociatedNamespaces.insert(EnclosingNamespace); 1289 1290 // Make sure we visit the bases of this base class. 1291 if (BaseDecl->bases_begin() != BaseDecl->bases_end()) 1292 Bases.push_back(BaseDecl); 1293 } 1294 } 1295 } 1296} 1297 1298// \brief Add the associated classes and namespaces for 1299// argument-dependent lookup with an argument of type T 1300// (C++ [basic.lookup.koenig]p2). 1301static void 1302addAssociatedClassesAndNamespaces(QualType T, 1303 ASTContext &Context, 1304 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1305 Sema::AssociatedClassSet &AssociatedClasses) { 1306 // C++ [basic.lookup.koenig]p2: 1307 // 1308 // For each argument type T in the function call, there is a set 1309 // of zero or more associated namespaces and a set of zero or more 1310 // associated classes to be considered. The sets of namespaces and 1311 // classes is determined entirely by the types of the function 1312 // arguments (and the namespace of any template template 1313 // argument). Typedef names and using-declarations used to specify 1314 // the types do not contribute to this set. The sets of namespaces 1315 // and classes are determined in the following way: 1316 T = Context.getCanonicalType(T).getUnqualifiedType(); 1317 1318 // -- If T is a pointer to U or an array of U, its associated 1319 // namespaces and classes are those associated with U. 1320 // 1321 // We handle this by unwrapping pointer and array types immediately, 1322 // to avoid unnecessary recursion. 1323 while (true) { 1324 if (const PointerType *Ptr = T->getAsPointerType()) 1325 T = Ptr->getPointeeType(); 1326 else if (const ArrayType *Ptr = Context.getAsArrayType(T)) 1327 T = Ptr->getElementType(); 1328 else 1329 break; 1330 } 1331 1332 // -- If T is a fundamental type, its associated sets of 1333 // namespaces and classes are both empty. 1334 if (T->getAsBuiltinType()) 1335 return; 1336 1337 // -- If T is a class type (including unions), its associated 1338 // classes are: the class itself; the class of which it is a 1339 // member, if any; and its direct and indirect base 1340 // classes. Its associated namespaces are the namespaces in 1341 // which its associated classes are defined. 1342 if (const RecordType *ClassType = T->getAsRecordType()) 1343 if (CXXRecordDecl *ClassDecl 1344 = dyn_cast<CXXRecordDecl>(ClassType->getDecl())) { 1345 addAssociatedClassesAndNamespaces(ClassDecl, Context, 1346 AssociatedNamespaces, 1347 AssociatedClasses); 1348 return; 1349 } 1350 1351 // -- If T is an enumeration type, its associated namespace is 1352 // the namespace in which it is defined. If it is class 1353 // member, its associated class is the member’s class; else 1354 // it has no associated class. 1355 if (const EnumType *EnumT = T->getAsEnumType()) { 1356 EnumDecl *Enum = EnumT->getDecl(); 1357 1358 DeclContext *Ctx = Enum->getDeclContext(); 1359 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1360 AssociatedClasses.insert(EnclosingClass); 1361 1362 // Add the associated namespace for this class. 1363 while (Ctx->isRecord()) 1364 Ctx = Ctx->getParent(); 1365 if (NamespaceDecl *EnclosingNamespace = dyn_cast<NamespaceDecl>(Ctx)) 1366 AssociatedNamespaces.insert(EnclosingNamespace); 1367 1368 return; 1369 } 1370 1371 // -- If T is a function type, its associated namespaces and 1372 // classes are those associated with the function parameter 1373 // types and those associated with the return type. 1374 if (const FunctionType *FunctionType = T->getAsFunctionType()) { 1375 // Return type 1376 addAssociatedClassesAndNamespaces(FunctionType->getResultType(), 1377 Context, 1378 AssociatedNamespaces, AssociatedClasses); 1379 1380 const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FunctionType); 1381 if (!Proto) 1382 return; 1383 1384 // Argument types 1385 for (FunctionProtoType::arg_type_iterator Arg = Proto->arg_type_begin(), 1386 ArgEnd = Proto->arg_type_end(); 1387 Arg != ArgEnd; ++Arg) 1388 addAssociatedClassesAndNamespaces(*Arg, Context, 1389 AssociatedNamespaces, AssociatedClasses); 1390 1391 return; 1392 } 1393 1394 // -- If T is a pointer to a member function of a class X, its 1395 // associated namespaces and classes are those associated 1396 // with the function parameter types and return type, 1397 // together with those associated with X. 1398 // 1399 // -- If T is a pointer to a data member of class X, its 1400 // associated namespaces and classes are those associated 1401 // with the member type together with those associated with 1402 // X. 1403 if (const MemberPointerType *MemberPtr = T->getAsMemberPointerType()) { 1404 // Handle the type that the pointer to member points to. 1405 addAssociatedClassesAndNamespaces(MemberPtr->getPointeeType(), 1406 Context, 1407 AssociatedNamespaces, AssociatedClasses); 1408 1409 // Handle the class type into which this points. 1410 if (const RecordType *Class = MemberPtr->getClass()->getAsRecordType()) 1411 addAssociatedClassesAndNamespaces(cast<CXXRecordDecl>(Class->getDecl()), 1412 Context, 1413 AssociatedNamespaces, AssociatedClasses); 1414 1415 return; 1416 } 1417 1418 // FIXME: What about block pointers? 1419 // FIXME: What about Objective-C message sends? 1420} 1421 1422/// \brief Find the associated classes and namespaces for 1423/// argument-dependent lookup for a call with the given set of 1424/// arguments. 1425/// 1426/// This routine computes the sets of associated classes and associated 1427/// namespaces searched by argument-dependent lookup 1428/// (C++ [basic.lookup.argdep]) for a given set of arguments. 1429void 1430Sema::FindAssociatedClassesAndNamespaces(Expr **Args, unsigned NumArgs, 1431 AssociatedNamespaceSet &AssociatedNamespaces, 1432 AssociatedClassSet &AssociatedClasses) { 1433 AssociatedNamespaces.clear(); 1434 AssociatedClasses.clear(); 1435 1436 // C++ [basic.lookup.koenig]p2: 1437 // For each argument type T in the function call, there is a set 1438 // of zero or more associated namespaces and a set of zero or more 1439 // associated classes to be considered. The sets of namespaces and 1440 // classes is determined entirely by the types of the function 1441 // arguments (and the namespace of any template template 1442 // argument). 1443 for (unsigned ArgIdx = 0; ArgIdx != NumArgs; ++ArgIdx) { 1444 Expr *Arg = Args[ArgIdx]; 1445 1446 if (Arg->getType() != Context.OverloadTy) { 1447 addAssociatedClassesAndNamespaces(Arg->getType(), Context, 1448 AssociatedNamespaces, AssociatedClasses); 1449 continue; 1450 } 1451 1452 // [...] In addition, if the argument is the name or address of a 1453 // set of overloaded functions and/or function templates, its 1454 // associated classes and namespaces are the union of those 1455 // associated with each of the members of the set: the namespace 1456 // in which the function or function template is defined and the 1457 // classes and namespaces associated with its (non-dependent) 1458 // parameter types and return type. 1459 DeclRefExpr *DRE = 0; 1460 if (UnaryOperator *unaryOp = dyn_cast<UnaryOperator>(Arg)) { 1461 if (unaryOp->getOpcode() == UnaryOperator::AddrOf) 1462 DRE = dyn_cast<DeclRefExpr>(unaryOp->getSubExpr()); 1463 } else 1464 DRE = dyn_cast<DeclRefExpr>(Arg); 1465 if (!DRE) 1466 continue; 1467 1468 OverloadedFunctionDecl *Ovl 1469 = dyn_cast<OverloadedFunctionDecl>(DRE->getDecl()); 1470 if (!Ovl) 1471 continue; 1472 1473 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 1474 FuncEnd = Ovl->function_end(); 1475 Func != FuncEnd; ++Func) { 1476 FunctionDecl *FDecl = cast<FunctionDecl>(*Func); 1477 1478 // Add the namespace in which this function was defined. Note 1479 // that, if this is a member function, we do *not* consider the 1480 // enclosing namespace of its class. 1481 DeclContext *Ctx = FDecl->getDeclContext(); 1482 if (NamespaceDecl *EnclosingNamespace = dyn_cast<NamespaceDecl>(Ctx)) 1483 AssociatedNamespaces.insert(EnclosingNamespace); 1484 1485 // Add the classes and namespaces associated with the parameter 1486 // types and return type of this function. 1487 addAssociatedClassesAndNamespaces(FDecl->getType(), Context, 1488 AssociatedNamespaces, AssociatedClasses); 1489 } 1490 } 1491} 1492 1493/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is 1494/// an acceptable non-member overloaded operator for a call whose 1495/// arguments have types T1 (and, if non-empty, T2). This routine 1496/// implements the check in C++ [over.match.oper]p3b2 concerning 1497/// enumeration types. 1498static bool 1499IsAcceptableNonMemberOperatorCandidate(FunctionDecl *Fn, 1500 QualType T1, QualType T2, 1501 ASTContext &Context) { 1502 if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType())) 1503 return true; 1504 1505 if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType())) 1506 return true; 1507 1508 const FunctionProtoType *Proto = Fn->getType()->getAsFunctionProtoType(); 1509 if (Proto->getNumArgs() < 1) 1510 return false; 1511 1512 if (T1->isEnumeralType()) { 1513 QualType ArgType = Proto->getArgType(0).getNonReferenceType(); 1514 if (Context.getCanonicalType(T1).getUnqualifiedType() 1515 == Context.getCanonicalType(ArgType).getUnqualifiedType()) 1516 return true; 1517 } 1518 1519 if (Proto->getNumArgs() < 2) 1520 return false; 1521 1522 if (!T2.isNull() && T2->isEnumeralType()) { 1523 QualType ArgType = Proto->getArgType(1).getNonReferenceType(); 1524 if (Context.getCanonicalType(T2).getUnqualifiedType() 1525 == Context.getCanonicalType(ArgType).getUnqualifiedType()) 1526 return true; 1527 } 1528 1529 return false; 1530} 1531 1532/// \brief Find the protocol with the given name, if any. 1533ObjCProtocolDecl *Sema::LookupProtocol(IdentifierInfo *II) { 1534 Decl *D = LookupName(TUScope, II, LookupObjCProtocolName).getAsDecl(); 1535 return cast_or_null<ObjCProtocolDecl>(D); 1536} 1537 1538/// \brief Find the Objective-C implementation with the given name, if 1539/// any. 1540ObjCImplementationDecl *Sema::LookupObjCImplementation(IdentifierInfo *II) { 1541 Decl *D = LookupName(TUScope, II, LookupObjCImplementationName).getAsDecl(); 1542 return cast_or_null<ObjCImplementationDecl>(D); 1543} 1544 1545/// \brief Find the Objective-C category implementation with the given 1546/// name, if any. 1547ObjCCategoryImplDecl *Sema::LookupObjCCategoryImpl(IdentifierInfo *II) { 1548 Decl *D = LookupName(TUScope, II, LookupObjCCategoryImplName).getAsDecl(); 1549 return cast_or_null<ObjCCategoryImplDecl>(D); 1550} 1551 1552void Sema::LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S, 1553 QualType T1, QualType T2, 1554 FunctionSet &Functions) { 1555 // C++ [over.match.oper]p3: 1556 // -- The set of non-member candidates is the result of the 1557 // unqualified lookup of operator@ in the context of the 1558 // expression according to the usual rules for name lookup in 1559 // unqualified function calls (3.4.2) except that all member 1560 // functions are ignored. However, if no operand has a class 1561 // type, only those non-member functions in the lookup set 1562 // that have a first parameter of type T1 or “reference to 1563 // (possibly cv-qualified) T1”, when T1 is an enumeration 1564 // type, or (if there is a right operand) a second parameter 1565 // of type T2 or “reference to (possibly cv-qualified) T2”, 1566 // when T2 is an enumeration type, are candidate functions. 1567 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 1568 LookupResult Operators = LookupName(S, OpName, LookupOperatorName); 1569 1570 assert(!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous"); 1571 1572 if (!Operators) 1573 return; 1574 1575 for (LookupResult::iterator Op = Operators.begin(), OpEnd = Operators.end(); 1576 Op != OpEnd; ++Op) { 1577 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*Op)) 1578 if (IsAcceptableNonMemberOperatorCandidate(FD, T1, T2, Context)) 1579 Functions.insert(FD); // FIXME: canonical FD 1580 } 1581} 1582 1583void Sema::ArgumentDependentLookup(DeclarationName Name, 1584 Expr **Args, unsigned NumArgs, 1585 FunctionSet &Functions) { 1586 // Find all of the associated namespaces and classes based on the 1587 // arguments we have. 1588 AssociatedNamespaceSet AssociatedNamespaces; 1589 AssociatedClassSet AssociatedClasses; 1590 FindAssociatedClassesAndNamespaces(Args, NumArgs, 1591 AssociatedNamespaces, AssociatedClasses); 1592 1593 // C++ [basic.lookup.argdep]p3: 1594 // Let X be the lookup set produced by unqualified lookup (3.4.1) 1595 // and let Y be the lookup set produced by argument dependent 1596 // lookup (defined as follows). If X contains [...] then Y is 1597 // empty. Otherwise Y is the set of declarations found in the 1598 // namespaces associated with the argument types as described 1599 // below. The set of declarations found by the lookup of the name 1600 // is the union of X and Y. 1601 // 1602 // Here, we compute Y and add its members to the overloaded 1603 // candidate set. 1604 for (AssociatedNamespaceSet::iterator NS = AssociatedNamespaces.begin(), 1605 NSEnd = AssociatedNamespaces.end(); 1606 NS != NSEnd; ++NS) { 1607 // When considering an associated namespace, the lookup is the 1608 // same as the lookup performed when the associated namespace is 1609 // used as a qualifier (3.4.3.2) except that: 1610 // 1611 // -- Any using-directives in the associated namespace are 1612 // ignored. 1613 // 1614 // -- FIXME: Any namespace-scope friend functions declared in 1615 // associated classes are visible within their respective 1616 // namespaces even if they are not visible during an ordinary 1617 // lookup (11.4). 1618 DeclContext::lookup_iterator I, E; 1619 for (llvm::tie(I, E) = (*NS)->lookup(Context, Name); I != E; ++I) { 1620 FunctionDecl *Func = dyn_cast<FunctionDecl>(*I); 1621 if (!Func) 1622 break; 1623 1624 Functions.insert(Func); 1625 } 1626 } 1627} 1628