SemaLookup.cpp revision 202379
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 "Lookup.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/CXXInheritance.h" 18#include "clang/AST/Decl.h" 19#include "clang/AST/DeclCXX.h" 20#include "clang/AST/DeclObjC.h" 21#include "clang/AST/DeclTemplate.h" 22#include "clang/AST/Expr.h" 23#include "clang/AST/ExprCXX.h" 24#include "clang/Parse/DeclSpec.h" 25#include "clang/Basic/Builtins.h" 26#include "clang/Basic/LangOptions.h" 27#include "llvm/ADT/STLExtras.h" 28#include "llvm/ADT/SmallPtrSet.h" 29#include "llvm/Support/ErrorHandling.h" 30#include <list> 31#include <set> 32#include <vector> 33#include <iterator> 34#include <utility> 35#include <algorithm> 36 37using namespace clang; 38 39namespace { 40 class UnqualUsingEntry { 41 const DeclContext *Nominated; 42 const DeclContext *CommonAncestor; 43 44 public: 45 UnqualUsingEntry(const DeclContext *Nominated, 46 const DeclContext *CommonAncestor) 47 : Nominated(Nominated), CommonAncestor(CommonAncestor) { 48 } 49 50 const DeclContext *getCommonAncestor() const { 51 return CommonAncestor; 52 } 53 54 const DeclContext *getNominatedNamespace() const { 55 return Nominated; 56 } 57 58 // Sort by the pointer value of the common ancestor. 59 struct Comparator { 60 bool operator()(const UnqualUsingEntry &L, const UnqualUsingEntry &R) { 61 return L.getCommonAncestor() < R.getCommonAncestor(); 62 } 63 64 bool operator()(const UnqualUsingEntry &E, const DeclContext *DC) { 65 return E.getCommonAncestor() < DC; 66 } 67 68 bool operator()(const DeclContext *DC, const UnqualUsingEntry &E) { 69 return DC < E.getCommonAncestor(); 70 } 71 }; 72 }; 73 74 /// A collection of using directives, as used by C++ unqualified 75 /// lookup. 76 class UnqualUsingDirectiveSet { 77 typedef llvm::SmallVector<UnqualUsingEntry, 8> ListTy; 78 79 ListTy list; 80 llvm::SmallPtrSet<DeclContext*, 8> visited; 81 82 public: 83 UnqualUsingDirectiveSet() {} 84 85 void visitScopeChain(Scope *S, Scope *InnermostFileScope) { 86 // C++ [namespace.udir]p1: 87 // During unqualified name lookup, the names appear as if they 88 // were declared in the nearest enclosing namespace which contains 89 // both the using-directive and the nominated namespace. 90 DeclContext *InnermostFileDC 91 = static_cast<DeclContext*>(InnermostFileScope->getEntity()); 92 assert(InnermostFileDC && InnermostFileDC->isFileContext()); 93 94 for (; S; S = S->getParent()) { 95 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) { 96 DeclContext *EffectiveDC = (Ctx->isFileContext() ? Ctx : InnermostFileDC); 97 visit(Ctx, EffectiveDC); 98 } else { 99 Scope::udir_iterator I = S->using_directives_begin(), 100 End = S->using_directives_end(); 101 102 for (; I != End; ++I) 103 visit(I->getAs<UsingDirectiveDecl>(), InnermostFileDC); 104 } 105 } 106 } 107 108 // Visits a context and collect all of its using directives 109 // recursively. Treats all using directives as if they were 110 // declared in the context. 111 // 112 // A given context is only every visited once, so it is important 113 // that contexts be visited from the inside out in order to get 114 // the effective DCs right. 115 void visit(DeclContext *DC, DeclContext *EffectiveDC) { 116 if (!visited.insert(DC)) 117 return; 118 119 addUsingDirectives(DC, EffectiveDC); 120 } 121 122 // Visits a using directive and collects all of its using 123 // directives recursively. Treats all using directives as if they 124 // were declared in the effective DC. 125 void visit(UsingDirectiveDecl *UD, DeclContext *EffectiveDC) { 126 DeclContext *NS = UD->getNominatedNamespace(); 127 if (!visited.insert(NS)) 128 return; 129 130 addUsingDirective(UD, EffectiveDC); 131 addUsingDirectives(NS, EffectiveDC); 132 } 133 134 // Adds all the using directives in a context (and those nominated 135 // by its using directives, transitively) as if they appeared in 136 // the given effective context. 137 void addUsingDirectives(DeclContext *DC, DeclContext *EffectiveDC) { 138 llvm::SmallVector<DeclContext*,4> queue; 139 while (true) { 140 DeclContext::udir_iterator I, End; 141 for (llvm::tie(I, End) = DC->getUsingDirectives(); I != End; ++I) { 142 UsingDirectiveDecl *UD = *I; 143 DeclContext *NS = UD->getNominatedNamespace(); 144 if (visited.insert(NS)) { 145 addUsingDirective(UD, EffectiveDC); 146 queue.push_back(NS); 147 } 148 } 149 150 if (queue.empty()) 151 return; 152 153 DC = queue.back(); 154 queue.pop_back(); 155 } 156 } 157 158 // Add a using directive as if it had been declared in the given 159 // context. This helps implement C++ [namespace.udir]p3: 160 // The using-directive is transitive: if a scope contains a 161 // using-directive that nominates a second namespace that itself 162 // contains using-directives, the effect is as if the 163 // using-directives from the second namespace also appeared in 164 // the first. 165 void addUsingDirective(UsingDirectiveDecl *UD, DeclContext *EffectiveDC) { 166 // Find the common ancestor between the effective context and 167 // the nominated namespace. 168 DeclContext *Common = UD->getNominatedNamespace(); 169 while (!Common->Encloses(EffectiveDC)) 170 Common = Common->getParent(); 171 Common = Common->getPrimaryContext(); 172 173 list.push_back(UnqualUsingEntry(UD->getNominatedNamespace(), Common)); 174 } 175 176 void done() { 177 std::sort(list.begin(), list.end(), UnqualUsingEntry::Comparator()); 178 } 179 180 typedef ListTy::iterator iterator; 181 typedef ListTy::const_iterator const_iterator; 182 183 iterator begin() { return list.begin(); } 184 iterator end() { return list.end(); } 185 const_iterator begin() const { return list.begin(); } 186 const_iterator end() const { return list.end(); } 187 188 std::pair<const_iterator,const_iterator> 189 getNamespacesFor(DeclContext *DC) const { 190 return std::equal_range(begin(), end(), DC->getPrimaryContext(), 191 UnqualUsingEntry::Comparator()); 192 } 193 }; 194} 195 196static bool IsAcceptableIDNS(NamedDecl *D, unsigned IDNS) { 197 return D->isInIdentifierNamespace(IDNS); 198} 199 200static bool IsAcceptableOperatorName(NamedDecl *D, unsigned IDNS) { 201 return D->isInIdentifierNamespace(IDNS) && 202 !D->getDeclContext()->isRecord(); 203} 204 205static bool IsAcceptableNestedNameSpecifierName(NamedDecl *D, unsigned IDNS) { 206 // This lookup ignores everything that isn't a type. 207 208 // This is a fast check for the far most common case. 209 if (D->isInIdentifierNamespace(Decl::IDNS_Tag)) 210 return true; 211 212 if (isa<UsingShadowDecl>(D)) 213 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 214 215 return isa<TypeDecl>(D); 216} 217 218static bool IsAcceptableNamespaceName(NamedDecl *D, unsigned IDNS) { 219 // We don't need to look through using decls here because 220 // using decls aren't allowed to name namespaces. 221 222 return isa<NamespaceDecl>(D) || isa<NamespaceAliasDecl>(D); 223} 224 225/// Gets the default result filter for the given lookup. 226static inline 227LookupResult::ResultFilter getResultFilter(Sema::LookupNameKind NameKind) { 228 switch (NameKind) { 229 case Sema::LookupOrdinaryName: 230 case Sema::LookupTagName: 231 case Sema::LookupMemberName: 232 case Sema::LookupRedeclarationWithLinkage: // FIXME: check linkage, scoping 233 case Sema::LookupUsingDeclName: 234 case Sema::LookupObjCProtocolName: 235 case Sema::LookupObjCImplementationName: 236 return &IsAcceptableIDNS; 237 238 case Sema::LookupOperatorName: 239 return &IsAcceptableOperatorName; 240 241 case Sema::LookupNestedNameSpecifierName: 242 return &IsAcceptableNestedNameSpecifierName; 243 244 case Sema::LookupNamespaceName: 245 return &IsAcceptableNamespaceName; 246 } 247 248 llvm_unreachable("unkknown lookup kind"); 249 return 0; 250} 251 252// Retrieve the set of identifier namespaces that correspond to a 253// specific kind of name lookup. 254static inline unsigned getIDNS(Sema::LookupNameKind NameKind, 255 bool CPlusPlus, 256 bool Redeclaration) { 257 unsigned IDNS = 0; 258 switch (NameKind) { 259 case Sema::LookupOrdinaryName: 260 case Sema::LookupOperatorName: 261 case Sema::LookupRedeclarationWithLinkage: 262 IDNS = Decl::IDNS_Ordinary; 263 if (CPlusPlus) { 264 IDNS |= Decl::IDNS_Tag | Decl::IDNS_Member; 265 if (Redeclaration) IDNS |= Decl::IDNS_TagFriend | Decl::IDNS_OrdinaryFriend; 266 } 267 break; 268 269 case Sema::LookupTagName: 270 IDNS = Decl::IDNS_Tag; 271 if (CPlusPlus && Redeclaration) 272 IDNS |= Decl::IDNS_TagFriend; 273 break; 274 275 case Sema::LookupMemberName: 276 IDNS = Decl::IDNS_Member; 277 if (CPlusPlus) 278 IDNS |= Decl::IDNS_Tag | Decl::IDNS_Ordinary; 279 break; 280 281 case Sema::LookupNestedNameSpecifierName: 282 case Sema::LookupNamespaceName: 283 IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag | Decl::IDNS_Member; 284 break; 285 286 case Sema::LookupUsingDeclName: 287 IDNS = Decl::IDNS_Ordinary | Decl::IDNS_Tag 288 | Decl::IDNS_Member | Decl::IDNS_Using; 289 break; 290 291 case Sema::LookupObjCProtocolName: 292 IDNS = Decl::IDNS_ObjCProtocol; 293 break; 294 295 case Sema::LookupObjCImplementationName: 296 IDNS = Decl::IDNS_ObjCImplementation; 297 break; 298 } 299 return IDNS; 300} 301 302void LookupResult::configure() { 303 IDNS = getIDNS(LookupKind, 304 SemaRef.getLangOptions().CPlusPlus, 305 isForRedeclaration()); 306 IsAcceptableFn = getResultFilter(LookupKind); 307} 308 309// Necessary because CXXBasePaths is not complete in Sema.h 310void LookupResult::deletePaths(CXXBasePaths *Paths) { 311 delete Paths; 312} 313 314/// Resolves the result kind of this lookup. 315void LookupResult::resolveKind() { 316 unsigned N = Decls.size(); 317 318 // Fast case: no possible ambiguity. 319 if (N == 0) { 320 assert(ResultKind == NotFound); 321 return; 322 } 323 324 // If there's a single decl, we need to examine it to decide what 325 // kind of lookup this is. 326 if (N == 1) { 327 if (isa<FunctionTemplateDecl>(Decls[0])) 328 ResultKind = FoundOverloaded; 329 else if (isa<UnresolvedUsingValueDecl>(Decls[0])) 330 ResultKind = FoundUnresolvedValue; 331 return; 332 } 333 334 // Don't do any extra resolution if we've already resolved as ambiguous. 335 if (ResultKind == Ambiguous) return; 336 337 llvm::SmallPtrSet<NamedDecl*, 16> Unique; 338 339 bool Ambiguous = false; 340 bool HasTag = false, HasFunction = false, HasNonFunction = false; 341 bool HasFunctionTemplate = false, HasUnresolved = false; 342 343 unsigned UniqueTagIndex = 0; 344 345 unsigned I = 0; 346 while (I < N) { 347 NamedDecl *D = Decls[I]->getUnderlyingDecl(); 348 D = cast<NamedDecl>(D->getCanonicalDecl()); 349 350 if (!Unique.insert(D)) { 351 // If it's not unique, pull something off the back (and 352 // continue at this index). 353 Decls[I] = Decls[--N]; 354 } else { 355 // Otherwise, do some decl type analysis and then continue. 356 357 if (isa<UnresolvedUsingValueDecl>(D)) { 358 HasUnresolved = true; 359 } else if (isa<TagDecl>(D)) { 360 if (HasTag) 361 Ambiguous = true; 362 UniqueTagIndex = I; 363 HasTag = true; 364 } else if (isa<FunctionTemplateDecl>(D)) { 365 HasFunction = true; 366 HasFunctionTemplate = true; 367 } else if (isa<FunctionDecl>(D)) { 368 HasFunction = true; 369 } else { 370 if (HasNonFunction) 371 Ambiguous = true; 372 HasNonFunction = true; 373 } 374 I++; 375 } 376 } 377 378 // C++ [basic.scope.hiding]p2: 379 // A class name or enumeration name can be hidden by the name of 380 // an object, function, or enumerator declared in the same 381 // scope. If a class or enumeration name and an object, function, 382 // or enumerator are declared in the same scope (in any order) 383 // with the same name, the class or enumeration name is hidden 384 // wherever the object, function, or enumerator name is visible. 385 // But it's still an error if there are distinct tag types found, 386 // even if they're not visible. (ref?) 387 if (HideTags && HasTag && !Ambiguous && 388 (HasFunction || HasNonFunction || HasUnresolved)) 389 Decls[UniqueTagIndex] = Decls[--N]; 390 391 Decls.set_size(N); 392 393 if (HasNonFunction && (HasFunction || HasUnresolved)) 394 Ambiguous = true; 395 396 if (Ambiguous) 397 setAmbiguous(LookupResult::AmbiguousReference); 398 else if (HasUnresolved) 399 ResultKind = LookupResult::FoundUnresolvedValue; 400 else if (N > 1 || HasFunctionTemplate) 401 ResultKind = LookupResult::FoundOverloaded; 402 else 403 ResultKind = LookupResult::Found; 404} 405 406void LookupResult::addDeclsFromBasePaths(const CXXBasePaths &P) { 407 CXXBasePaths::paths_iterator I, E; 408 DeclContext::lookup_iterator DI, DE; 409 for (I = P.begin(), E = P.end(); I != E; ++I) 410 for (llvm::tie(DI,DE) = I->Decls; DI != DE; ++DI) 411 addDecl(*DI); 412} 413 414void LookupResult::setAmbiguousBaseSubobjects(CXXBasePaths &P) { 415 Paths = new CXXBasePaths; 416 Paths->swap(P); 417 addDeclsFromBasePaths(*Paths); 418 resolveKind(); 419 setAmbiguous(AmbiguousBaseSubobjects); 420} 421 422void LookupResult::setAmbiguousBaseSubobjectTypes(CXXBasePaths &P) { 423 Paths = new CXXBasePaths; 424 Paths->swap(P); 425 addDeclsFromBasePaths(*Paths); 426 resolveKind(); 427 setAmbiguous(AmbiguousBaseSubobjectTypes); 428} 429 430void LookupResult::print(llvm::raw_ostream &Out) { 431 Out << Decls.size() << " result(s)"; 432 if (isAmbiguous()) Out << ", ambiguous"; 433 if (Paths) Out << ", base paths present"; 434 435 for (iterator I = begin(), E = end(); I != E; ++I) { 436 Out << "\n"; 437 (*I)->print(Out, 2); 438 } 439} 440 441// Adds all qualifying matches for a name within a decl context to the 442// given lookup result. Returns true if any matches were found. 443static bool LookupDirect(LookupResult &R, const DeclContext *DC) { 444 bool Found = false; 445 446 DeclContext::lookup_const_iterator I, E; 447 for (llvm::tie(I, E) = DC->lookup(R.getLookupName()); I != E; ++I) { 448 if (R.isAcceptableDecl(*I)) { 449 R.addDecl(*I); 450 Found = true; 451 } 452 } 453 454 if (R.getLookupName().getNameKind() 455 == DeclarationName::CXXConversionFunctionName && 456 !R.getLookupName().getCXXNameType()->isDependentType() && 457 isa<CXXRecordDecl>(DC)) { 458 // C++ [temp.mem]p6: 459 // A specialization of a conversion function template is not found by 460 // name lookup. Instead, any conversion function templates visible in the 461 // context of the use are considered. [...] 462 const CXXRecordDecl *Record = cast<CXXRecordDecl>(DC); 463 if (!Record->isDefinition()) 464 return Found; 465 466 const UnresolvedSet *Unresolved = Record->getConversionFunctions(); 467 for (UnresolvedSet::iterator U = Unresolved->begin(), 468 UEnd = Unresolved->end(); 469 U != UEnd; ++U) { 470 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(*U); 471 if (!ConvTemplate) 472 continue; 473 474 // When we're performing lookup for the purposes of redeclaration, just 475 // add the conversion function template. When we deduce template 476 // arguments for specializations, we'll end up unifying the return 477 // type of the new declaration with the type of the function template. 478 if (R.isForRedeclaration()) { 479 R.addDecl(ConvTemplate); 480 Found = true; 481 continue; 482 } 483 484 // C++ [temp.mem]p6: 485 // [...] For each such operator, if argument deduction succeeds 486 // (14.9.2.3), the resulting specialization is used as if found by 487 // name lookup. 488 // 489 // When referencing a conversion function for any purpose other than 490 // a redeclaration (such that we'll be building an expression with the 491 // result), perform template argument deduction and place the 492 // specialization into the result set. We do this to avoid forcing all 493 // callers to perform special deduction for conversion functions. 494 Sema::TemplateDeductionInfo Info(R.getSema().Context); 495 FunctionDecl *Specialization = 0; 496 497 const FunctionProtoType *ConvProto 498 = ConvTemplate->getTemplatedDecl()->getType() 499 ->getAs<FunctionProtoType>(); 500 assert(ConvProto && "Nonsensical conversion function template type"); 501 502 // Compute the type of the function that we would expect the conversion 503 // function to have, if it were to match the name given. 504 // FIXME: Calling convention! 505 QualType ExpectedType 506 = R.getSema().Context.getFunctionType( 507 R.getLookupName().getCXXNameType(), 508 0, 0, ConvProto->isVariadic(), 509 ConvProto->getTypeQuals(), 510 false, false, 0, 0, 511 ConvProto->getNoReturnAttr()); 512 513 // Perform template argument deduction against the type that we would 514 // expect the function to have. 515 if (R.getSema().DeduceTemplateArguments(ConvTemplate, 0, ExpectedType, 516 Specialization, Info) 517 == Sema::TDK_Success) { 518 R.addDecl(Specialization); 519 Found = true; 520 } 521 } 522 } 523 524 return Found; 525} 526 527// Performs C++ unqualified lookup into the given file context. 528static bool 529CppNamespaceLookup(LookupResult &R, ASTContext &Context, DeclContext *NS, 530 UnqualUsingDirectiveSet &UDirs) { 531 532 assert(NS && NS->isFileContext() && "CppNamespaceLookup() requires namespace!"); 533 534 // Perform direct name lookup into the LookupCtx. 535 bool Found = LookupDirect(R, NS); 536 537 // Perform direct name lookup into the namespaces nominated by the 538 // using directives whose common ancestor is this namespace. 539 UnqualUsingDirectiveSet::const_iterator UI, UEnd; 540 llvm::tie(UI, UEnd) = UDirs.getNamespacesFor(NS); 541 542 for (; UI != UEnd; ++UI) 543 if (LookupDirect(R, UI->getNominatedNamespace())) 544 Found = true; 545 546 R.resolveKind(); 547 548 return Found; 549} 550 551static bool isNamespaceOrTranslationUnitScope(Scope *S) { 552 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) 553 return Ctx->isFileContext(); 554 return false; 555} 556 557// Find the next outer declaration context corresponding to this scope. 558static DeclContext *findOuterContext(Scope *S) { 559 for (S = S->getParent(); S; S = S->getParent()) 560 if (S->getEntity()) 561 return static_cast<DeclContext *>(S->getEntity())->getPrimaryContext(); 562 563 return 0; 564} 565 566bool Sema::CppLookupName(LookupResult &R, Scope *S) { 567 assert(getLangOptions().CPlusPlus && "Can perform only C++ lookup"); 568 569 DeclarationName Name = R.getLookupName(); 570 571 Scope *Initial = S; 572 IdentifierResolver::iterator 573 I = IdResolver.begin(Name), 574 IEnd = IdResolver.end(); 575 576 // First we lookup local scope. 577 // We don't consider using-directives, as per 7.3.4.p1 [namespace.udir] 578 // ...During unqualified name lookup (3.4.1), the names appear as if 579 // they were declared in the nearest enclosing namespace which contains 580 // both the using-directive and the nominated namespace. 581 // [Note: in this context, "contains" means "contains directly or 582 // indirectly". 583 // 584 // For example: 585 // namespace A { int i; } 586 // void foo() { 587 // int i; 588 // { 589 // using namespace A; 590 // ++i; // finds local 'i', A::i appears at global scope 591 // } 592 // } 593 // 594 for (; S && !isNamespaceOrTranslationUnitScope(S); S = S->getParent()) { 595 // Check whether the IdResolver has anything in this scope. 596 bool Found = false; 597 for (; I != IEnd && S->isDeclScope(DeclPtrTy::make(*I)); ++I) { 598 if (R.isAcceptableDecl(*I)) { 599 Found = true; 600 R.addDecl(*I); 601 } 602 } 603 if (Found) { 604 R.resolveKind(); 605 return true; 606 } 607 608 if (DeclContext *Ctx = static_cast<DeclContext*>(S->getEntity())) { 609 DeclContext *OuterCtx = findOuterContext(S); 610 for (; Ctx && Ctx->getPrimaryContext() != OuterCtx; 611 Ctx = Ctx->getLookupParent()) { 612 // We do not directly look into function or method contexts 613 // (since all local variables are found via the identifier 614 // changes) or in transparent contexts (since those entities 615 // will be found in the nearest enclosing non-transparent 616 // context). 617 if (Ctx->isFunctionOrMethod() || Ctx->isTransparentContext()) 618 continue; 619 620 // Perform qualified name lookup into this context. 621 // FIXME: In some cases, we know that every name that could be found by 622 // this qualified name lookup will also be on the identifier chain. For 623 // example, inside a class without any base classes, we never need to 624 // perform qualified lookup because all of the members are on top of the 625 // identifier chain. 626 if (LookupQualifiedName(R, Ctx, /*InUnqualifiedLookup=*/true)) 627 return true; 628 } 629 } 630 } 631 632 // Stop if we ran out of scopes. 633 // FIXME: This really, really shouldn't be happening. 634 if (!S) return false; 635 636 // Collect UsingDirectiveDecls in all scopes, and recursively all 637 // nominated namespaces by those using-directives. 638 // 639 // FIXME: Cache this sorted list in Scope structure, and DeclContext, so we 640 // don't build it for each lookup! 641 642 UnqualUsingDirectiveSet UDirs; 643 UDirs.visitScopeChain(Initial, S); 644 UDirs.done(); 645 646 // Lookup namespace scope, and global scope. 647 // Unqualified name lookup in C++ requires looking into scopes 648 // that aren't strictly lexical, and therefore we walk through the 649 // context as well as walking through the scopes. 650 651 for (; S; S = S->getParent()) { 652 DeclContext *Ctx = static_cast<DeclContext *>(S->getEntity()); 653 if (!Ctx || Ctx->isTransparentContext()) 654 continue; 655 656 assert(Ctx && Ctx->isFileContext() && 657 "We should have been looking only at file context here already."); 658 659 // Check whether the IdResolver has anything in this scope. 660 bool Found = false; 661 for (; I != IEnd && S->isDeclScope(DeclPtrTy::make(*I)); ++I) { 662 if (R.isAcceptableDecl(*I)) { 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 Found = true; 668 R.addDecl(*I); 669 } 670 } 671 672 // Look into context considering using-directives. 673 if (CppNamespaceLookup(R, Context, Ctx, UDirs)) 674 Found = true; 675 676 if (Found) { 677 R.resolveKind(); 678 return true; 679 } 680 681 if (R.isForRedeclaration() && !Ctx->isTransparentContext()) 682 return false; 683 } 684 685 return !R.empty(); 686} 687 688/// @brief Perform unqualified name lookup starting from a given 689/// scope. 690/// 691/// Unqualified name lookup (C++ [basic.lookup.unqual], C99 6.2.1) is 692/// used to find names within the current scope. For example, 'x' in 693/// @code 694/// int x; 695/// int f() { 696/// return x; // unqualified name look finds 'x' in the global scope 697/// } 698/// @endcode 699/// 700/// Different lookup criteria can find different names. For example, a 701/// particular scope can have both a struct and a function of the same 702/// name, and each can be found by certain lookup criteria. For more 703/// information about lookup criteria, see the documentation for the 704/// class LookupCriteria. 705/// 706/// @param S The scope from which unqualified name lookup will 707/// begin. If the lookup criteria permits, name lookup may also search 708/// in the parent scopes. 709/// 710/// @param Name The name of the entity that we are searching for. 711/// 712/// @param Loc If provided, the source location where we're performing 713/// name lookup. At present, this is only used to produce diagnostics when 714/// C library functions (like "malloc") are implicitly declared. 715/// 716/// @returns The result of name lookup, which includes zero or more 717/// declarations and possibly additional information used to diagnose 718/// ambiguities. 719bool Sema::LookupName(LookupResult &R, Scope *S, bool AllowBuiltinCreation) { 720 DeclarationName Name = R.getLookupName(); 721 if (!Name) return false; 722 723 LookupNameKind NameKind = R.getLookupKind(); 724 725 if (!getLangOptions().CPlusPlus) { 726 // Unqualified name lookup in C/Objective-C is purely lexical, so 727 // search in the declarations attached to the name. 728 729 if (NameKind == Sema::LookupRedeclarationWithLinkage) { 730 // Find the nearest non-transparent declaration scope. 731 while (!(S->getFlags() & Scope::DeclScope) || 732 (S->getEntity() && 733 static_cast<DeclContext *>(S->getEntity()) 734 ->isTransparentContext())) 735 S = S->getParent(); 736 } 737 738 unsigned IDNS = R.getIdentifierNamespace(); 739 740 // Scan up the scope chain looking for a decl that matches this 741 // identifier that is in the appropriate namespace. This search 742 // should not take long, as shadowing of names is uncommon, and 743 // deep shadowing is extremely uncommon. 744 bool LeftStartingScope = false; 745 746 for (IdentifierResolver::iterator I = IdResolver.begin(Name), 747 IEnd = IdResolver.end(); 748 I != IEnd; ++I) 749 if ((*I)->isInIdentifierNamespace(IDNS)) { 750 if (NameKind == LookupRedeclarationWithLinkage) { 751 // Determine whether this (or a previous) declaration is 752 // out-of-scope. 753 if (!LeftStartingScope && !S->isDeclScope(DeclPtrTy::make(*I))) 754 LeftStartingScope = true; 755 756 // If we found something outside of our starting scope that 757 // does not have linkage, skip it. 758 if (LeftStartingScope && !((*I)->hasLinkage())) 759 continue; 760 } 761 762 R.addDecl(*I); 763 764 if ((*I)->getAttr<OverloadableAttr>()) { 765 // If this declaration has the "overloadable" attribute, we 766 // might have a set of overloaded functions. 767 768 // Figure out what scope the identifier is in. 769 while (!(S->getFlags() & Scope::DeclScope) || 770 !S->isDeclScope(DeclPtrTy::make(*I))) 771 S = S->getParent(); 772 773 // Find the last declaration in this scope (with the same 774 // name, naturally). 775 IdentifierResolver::iterator LastI = I; 776 for (++LastI; LastI != IEnd; ++LastI) { 777 if (!S->isDeclScope(DeclPtrTy::make(*LastI))) 778 break; 779 R.addDecl(*LastI); 780 } 781 } 782 783 R.resolveKind(); 784 785 return true; 786 } 787 } else { 788 // Perform C++ unqualified name lookup. 789 if (CppLookupName(R, S)) 790 return true; 791 } 792 793 // If we didn't find a use of this identifier, and if the identifier 794 // corresponds to a compiler builtin, create the decl object for the builtin 795 // now, injecting it into translation unit scope, and return it. 796 if (NameKind == LookupOrdinaryName || 797 NameKind == LookupRedeclarationWithLinkage) { 798 IdentifierInfo *II = Name.getAsIdentifierInfo(); 799 if (II && AllowBuiltinCreation) { 800 // If this is a builtin on this (or all) targets, create the decl. 801 if (unsigned BuiltinID = II->getBuiltinID()) { 802 // In C++, we don't have any predefined library functions like 803 // 'malloc'. Instead, we'll just error. 804 if (getLangOptions().CPlusPlus && 805 Context.BuiltinInfo.isPredefinedLibFunction(BuiltinID)) 806 return false; 807 808 NamedDecl *D = LazilyCreateBuiltin((IdentifierInfo *)II, BuiltinID, 809 S, R.isForRedeclaration(), 810 R.getNameLoc()); 811 if (D) R.addDecl(D); 812 return (D != NULL); 813 } 814 } 815 } 816 return false; 817} 818 819/// @brief Perform qualified name lookup in the namespaces nominated by 820/// using directives by the given context. 821/// 822/// C++98 [namespace.qual]p2: 823/// Given X::m (where X is a user-declared namespace), or given ::m 824/// (where X is the global namespace), let S be the set of all 825/// declarations of m in X and in the transitive closure of all 826/// namespaces nominated by using-directives in X and its used 827/// namespaces, except that using-directives are ignored in any 828/// namespace, including X, directly containing one or more 829/// declarations of m. No namespace is searched more than once in 830/// the lookup of a name. If S is the empty set, the program is 831/// ill-formed. Otherwise, if S has exactly one member, or if the 832/// context of the reference is a using-declaration 833/// (namespace.udecl), S is the required set of declarations of 834/// m. Otherwise if the use of m is not one that allows a unique 835/// declaration to be chosen from S, the program is ill-formed. 836/// C++98 [namespace.qual]p5: 837/// During the lookup of a qualified namespace member name, if the 838/// lookup finds more than one declaration of the member, and if one 839/// declaration introduces a class name or enumeration name and the 840/// other declarations either introduce the same object, the same 841/// enumerator or a set of functions, the non-type name hides the 842/// class or enumeration name if and only if the declarations are 843/// from the same namespace; otherwise (the declarations are from 844/// different namespaces), the program is ill-formed. 845static bool LookupQualifiedNameInUsingDirectives(LookupResult &R, 846 DeclContext *StartDC) { 847 assert(StartDC->isFileContext() && "start context is not a file context"); 848 849 DeclContext::udir_iterator I = StartDC->using_directives_begin(); 850 DeclContext::udir_iterator E = StartDC->using_directives_end(); 851 852 if (I == E) return false; 853 854 // We have at least added all these contexts to the queue. 855 llvm::DenseSet<DeclContext*> Visited; 856 Visited.insert(StartDC); 857 858 // We have not yet looked into these namespaces, much less added 859 // their "using-children" to the queue. 860 llvm::SmallVector<NamespaceDecl*, 8> Queue; 861 862 // We have already looked into the initial namespace; seed the queue 863 // with its using-children. 864 for (; I != E; ++I) { 865 NamespaceDecl *ND = (*I)->getNominatedNamespace()->getOriginalNamespace(); 866 if (Visited.insert(ND).second) 867 Queue.push_back(ND); 868 } 869 870 // The easiest way to implement the restriction in [namespace.qual]p5 871 // is to check whether any of the individual results found a tag 872 // and, if so, to declare an ambiguity if the final result is not 873 // a tag. 874 bool FoundTag = false; 875 bool FoundNonTag = false; 876 877 LookupResult LocalR(LookupResult::Temporary, R); 878 879 bool Found = false; 880 while (!Queue.empty()) { 881 NamespaceDecl *ND = Queue.back(); 882 Queue.pop_back(); 883 884 // We go through some convolutions here to avoid copying results 885 // between LookupResults. 886 bool UseLocal = !R.empty(); 887 LookupResult &DirectR = UseLocal ? LocalR : R; 888 bool FoundDirect = LookupDirect(DirectR, ND); 889 890 if (FoundDirect) { 891 // First do any local hiding. 892 DirectR.resolveKind(); 893 894 // If the local result is a tag, remember that. 895 if (DirectR.isSingleTagDecl()) 896 FoundTag = true; 897 else 898 FoundNonTag = true; 899 900 // Append the local results to the total results if necessary. 901 if (UseLocal) { 902 R.addAllDecls(LocalR); 903 LocalR.clear(); 904 } 905 } 906 907 // If we find names in this namespace, ignore its using directives. 908 if (FoundDirect) { 909 Found = true; 910 continue; 911 } 912 913 for (llvm::tie(I,E) = ND->getUsingDirectives(); I != E; ++I) { 914 NamespaceDecl *Nom = (*I)->getNominatedNamespace(); 915 if (Visited.insert(Nom).second) 916 Queue.push_back(Nom); 917 } 918 } 919 920 if (Found) { 921 if (FoundTag && FoundNonTag) 922 R.setAmbiguousQualifiedTagHiding(); 923 else 924 R.resolveKind(); 925 } 926 927 return Found; 928} 929 930/// \brief Perform qualified name lookup into a given context. 931/// 932/// Qualified name lookup (C++ [basic.lookup.qual]) is used to find 933/// names when the context of those names is explicit specified, e.g., 934/// "std::vector" or "x->member", or as part of unqualified name lookup. 935/// 936/// Different lookup criteria can find different names. For example, a 937/// particular scope can have both a struct and a function of the same 938/// name, and each can be found by certain lookup criteria. For more 939/// information about lookup criteria, see the documentation for the 940/// class LookupCriteria. 941/// 942/// \param R captures both the lookup criteria and any lookup results found. 943/// 944/// \param LookupCtx The context in which qualified name lookup will 945/// search. If the lookup criteria permits, name lookup may also search 946/// in the parent contexts or (for C++ classes) base classes. 947/// 948/// \param InUnqualifiedLookup true if this is qualified name lookup that 949/// occurs as part of unqualified name lookup. 950/// 951/// \returns true if lookup succeeded, false if it failed. 952bool Sema::LookupQualifiedName(LookupResult &R, DeclContext *LookupCtx, 953 bool InUnqualifiedLookup) { 954 assert(LookupCtx && "Sema::LookupQualifiedName requires a lookup context"); 955 956 if (!R.getLookupName()) 957 return false; 958 959 // Make sure that the declaration context is complete. 960 assert((!isa<TagDecl>(LookupCtx) || 961 LookupCtx->isDependentContext() || 962 cast<TagDecl>(LookupCtx)->isDefinition() || 963 Context.getTypeDeclType(cast<TagDecl>(LookupCtx))->getAs<TagType>() 964 ->isBeingDefined()) && 965 "Declaration context must already be complete!"); 966 967 // Perform qualified name lookup into the LookupCtx. 968 if (LookupDirect(R, LookupCtx)) { 969 R.resolveKind(); 970 return true; 971 } 972 973 // Don't descend into implied contexts for redeclarations. 974 // C++98 [namespace.qual]p6: 975 // In a declaration for a namespace member in which the 976 // declarator-id is a qualified-id, given that the qualified-id 977 // for the namespace member has the form 978 // nested-name-specifier unqualified-id 979 // the unqualified-id shall name a member of the namespace 980 // designated by the nested-name-specifier. 981 // See also [class.mfct]p5 and [class.static.data]p2. 982 if (R.isForRedeclaration()) 983 return false; 984 985 // If this is a namespace, look it up in the implied namespaces. 986 if (LookupCtx->isFileContext()) 987 return LookupQualifiedNameInUsingDirectives(R, LookupCtx); 988 989 // If this isn't a C++ class, we aren't allowed to look into base 990 // classes, we're done. 991 CXXRecordDecl *LookupRec = dyn_cast<CXXRecordDecl>(LookupCtx); 992 if (!LookupRec) 993 return false; 994 995 // If we're performing qualified name lookup into a dependent class, 996 // then we are actually looking into a current instantiation. If we have any 997 // dependent base classes, then we either have to delay lookup until 998 // template instantiation time (at which point all bases will be available) 999 // or we have to fail. 1000 if (!InUnqualifiedLookup && LookupRec->isDependentContext() && 1001 LookupRec->hasAnyDependentBases()) { 1002 R.setNotFoundInCurrentInstantiation(); 1003 return false; 1004 } 1005 1006 // Perform lookup into our base classes. 1007 CXXBasePaths Paths; 1008 Paths.setOrigin(LookupRec); 1009 1010 // Look for this member in our base classes 1011 CXXRecordDecl::BaseMatchesCallback *BaseCallback = 0; 1012 switch (R.getLookupKind()) { 1013 case LookupOrdinaryName: 1014 case LookupMemberName: 1015 case LookupRedeclarationWithLinkage: 1016 BaseCallback = &CXXRecordDecl::FindOrdinaryMember; 1017 break; 1018 1019 case LookupTagName: 1020 BaseCallback = &CXXRecordDecl::FindTagMember; 1021 break; 1022 1023 case LookupUsingDeclName: 1024 // This lookup is for redeclarations only. 1025 1026 case LookupOperatorName: 1027 case LookupNamespaceName: 1028 case LookupObjCProtocolName: 1029 case LookupObjCImplementationName: 1030 // These lookups will never find a member in a C++ class (or base class). 1031 return false; 1032 1033 case LookupNestedNameSpecifierName: 1034 BaseCallback = &CXXRecordDecl::FindNestedNameSpecifierMember; 1035 break; 1036 } 1037 1038 if (!LookupRec->lookupInBases(BaseCallback, 1039 R.getLookupName().getAsOpaquePtr(), Paths)) 1040 return false; 1041 1042 // C++ [class.member.lookup]p2: 1043 // [...] If the resulting set of declarations are not all from 1044 // sub-objects of the same type, or the set has a nonstatic member 1045 // and includes members from distinct sub-objects, there is an 1046 // ambiguity and the program is ill-formed. Otherwise that set is 1047 // the result of the lookup. 1048 // FIXME: support using declarations! 1049 QualType SubobjectType; 1050 int SubobjectNumber = 0; 1051 for (CXXBasePaths::paths_iterator Path = Paths.begin(), PathEnd = Paths.end(); 1052 Path != PathEnd; ++Path) { 1053 const CXXBasePathElement &PathElement = Path->back(); 1054 1055 // Determine whether we're looking at a distinct sub-object or not. 1056 if (SubobjectType.isNull()) { 1057 // This is the first subobject we've looked at. Record its type. 1058 SubobjectType = Context.getCanonicalType(PathElement.Base->getType()); 1059 SubobjectNumber = PathElement.SubobjectNumber; 1060 } else if (SubobjectType 1061 != Context.getCanonicalType(PathElement.Base->getType())) { 1062 // We found members of the given name in two subobjects of 1063 // different types. This lookup is ambiguous. 1064 R.setAmbiguousBaseSubobjectTypes(Paths); 1065 return true; 1066 } else if (SubobjectNumber != PathElement.SubobjectNumber) { 1067 // We have a different subobject of the same type. 1068 1069 // C++ [class.member.lookup]p5: 1070 // A static member, a nested type or an enumerator defined in 1071 // a base class T can unambiguously be found even if an object 1072 // has more than one base class subobject of type T. 1073 Decl *FirstDecl = *Path->Decls.first; 1074 if (isa<VarDecl>(FirstDecl) || 1075 isa<TypeDecl>(FirstDecl) || 1076 isa<EnumConstantDecl>(FirstDecl)) 1077 continue; 1078 1079 if (isa<CXXMethodDecl>(FirstDecl)) { 1080 // Determine whether all of the methods are static. 1081 bool AllMethodsAreStatic = true; 1082 for (DeclContext::lookup_iterator Func = Path->Decls.first; 1083 Func != Path->Decls.second; ++Func) { 1084 if (!isa<CXXMethodDecl>(*Func)) { 1085 assert(isa<TagDecl>(*Func) && "Non-function must be a tag decl"); 1086 break; 1087 } 1088 1089 if (!cast<CXXMethodDecl>(*Func)->isStatic()) { 1090 AllMethodsAreStatic = false; 1091 break; 1092 } 1093 } 1094 1095 if (AllMethodsAreStatic) 1096 continue; 1097 } 1098 1099 // We have found a nonstatic member name in multiple, distinct 1100 // subobjects. Name lookup is ambiguous. 1101 R.setAmbiguousBaseSubobjects(Paths); 1102 return true; 1103 } 1104 } 1105 1106 // Lookup in a base class succeeded; return these results. 1107 1108 DeclContext::lookup_iterator I, E; 1109 for (llvm::tie(I,E) = Paths.front().Decls; I != E; ++I) 1110 R.addDecl(*I); 1111 R.resolveKind(); 1112 return true; 1113} 1114 1115/// @brief Performs name lookup for a name that was parsed in the 1116/// source code, and may contain a C++ scope specifier. 1117/// 1118/// This routine is a convenience routine meant to be called from 1119/// contexts that receive a name and an optional C++ scope specifier 1120/// (e.g., "N::M::x"). It will then perform either qualified or 1121/// unqualified name lookup (with LookupQualifiedName or LookupName, 1122/// respectively) on the given name and return those results. 1123/// 1124/// @param S The scope from which unqualified name lookup will 1125/// begin. 1126/// 1127/// @param SS An optional C++ scope-specifier, e.g., "::N::M". 1128/// 1129/// @param Name The name of the entity that name lookup will 1130/// search for. 1131/// 1132/// @param Loc If provided, the source location where we're performing 1133/// name lookup. At present, this is only used to produce diagnostics when 1134/// C library functions (like "malloc") are implicitly declared. 1135/// 1136/// @param EnteringContext Indicates whether we are going to enter the 1137/// context of the scope-specifier SS (if present). 1138/// 1139/// @returns True if any decls were found (but possibly ambiguous) 1140bool Sema::LookupParsedName(LookupResult &R, Scope *S, const CXXScopeSpec *SS, 1141 bool AllowBuiltinCreation, bool EnteringContext) { 1142 if (SS && SS->isInvalid()) { 1143 // When the scope specifier is invalid, don't even look for 1144 // anything. 1145 return false; 1146 } 1147 1148 if (SS && SS->isSet()) { 1149 if (DeclContext *DC = computeDeclContext(*SS, EnteringContext)) { 1150 // We have resolved the scope specifier to a particular declaration 1151 // contex, and will perform name lookup in that context. 1152 if (!DC->isDependentContext() && RequireCompleteDeclContext(*SS)) 1153 return false; 1154 1155 R.setContextRange(SS->getRange()); 1156 1157 return LookupQualifiedName(R, DC); 1158 } 1159 1160 // We could not resolve the scope specified to a specific declaration 1161 // context, which means that SS refers to an unknown specialization. 1162 // Name lookup can't find anything in this case. 1163 return false; 1164 } 1165 1166 // Perform unqualified name lookup starting in the given scope. 1167 return LookupName(R, S, AllowBuiltinCreation); 1168} 1169 1170 1171/// @brief Produce a diagnostic describing the ambiguity that resulted 1172/// from name lookup. 1173/// 1174/// @param Result The ambiguous name lookup result. 1175/// 1176/// @param Name The name of the entity that name lookup was 1177/// searching for. 1178/// 1179/// @param NameLoc The location of the name within the source code. 1180/// 1181/// @param LookupRange A source range that provides more 1182/// source-location information concerning the lookup itself. For 1183/// example, this range might highlight a nested-name-specifier that 1184/// precedes the name. 1185/// 1186/// @returns true 1187bool Sema::DiagnoseAmbiguousLookup(LookupResult &Result) { 1188 assert(Result.isAmbiguous() && "Lookup result must be ambiguous"); 1189 1190 DeclarationName Name = Result.getLookupName(); 1191 SourceLocation NameLoc = Result.getNameLoc(); 1192 SourceRange LookupRange = Result.getContextRange(); 1193 1194 switch (Result.getAmbiguityKind()) { 1195 case LookupResult::AmbiguousBaseSubobjects: { 1196 CXXBasePaths *Paths = Result.getBasePaths(); 1197 QualType SubobjectType = Paths->front().back().Base->getType(); 1198 Diag(NameLoc, diag::err_ambiguous_member_multiple_subobjects) 1199 << Name << SubobjectType << getAmbiguousPathsDisplayString(*Paths) 1200 << LookupRange; 1201 1202 DeclContext::lookup_iterator Found = Paths->front().Decls.first; 1203 while (isa<CXXMethodDecl>(*Found) && 1204 cast<CXXMethodDecl>(*Found)->isStatic()) 1205 ++Found; 1206 1207 Diag((*Found)->getLocation(), diag::note_ambiguous_member_found); 1208 1209 return true; 1210 } 1211 1212 case LookupResult::AmbiguousBaseSubobjectTypes: { 1213 Diag(NameLoc, diag::err_ambiguous_member_multiple_subobject_types) 1214 << Name << LookupRange; 1215 1216 CXXBasePaths *Paths = Result.getBasePaths(); 1217 std::set<Decl *> DeclsPrinted; 1218 for (CXXBasePaths::paths_iterator Path = Paths->begin(), 1219 PathEnd = Paths->end(); 1220 Path != PathEnd; ++Path) { 1221 Decl *D = *Path->Decls.first; 1222 if (DeclsPrinted.insert(D).second) 1223 Diag(D->getLocation(), diag::note_ambiguous_member_found); 1224 } 1225 1226 return true; 1227 } 1228 1229 case LookupResult::AmbiguousTagHiding: { 1230 Diag(NameLoc, diag::err_ambiguous_tag_hiding) << Name << LookupRange; 1231 1232 llvm::SmallPtrSet<NamedDecl*,8> TagDecls; 1233 1234 LookupResult::iterator DI, DE = Result.end(); 1235 for (DI = Result.begin(); DI != DE; ++DI) 1236 if (TagDecl *TD = dyn_cast<TagDecl>(*DI)) { 1237 TagDecls.insert(TD); 1238 Diag(TD->getLocation(), diag::note_hidden_tag); 1239 } 1240 1241 for (DI = Result.begin(); DI != DE; ++DI) 1242 if (!isa<TagDecl>(*DI)) 1243 Diag((*DI)->getLocation(), diag::note_hiding_object); 1244 1245 // For recovery purposes, go ahead and implement the hiding. 1246 Result.hideDecls(TagDecls); 1247 1248 return true; 1249 } 1250 1251 case LookupResult::AmbiguousReference: { 1252 Diag(NameLoc, diag::err_ambiguous_reference) << Name << LookupRange; 1253 1254 LookupResult::iterator DI = Result.begin(), DE = Result.end(); 1255 for (; DI != DE; ++DI) 1256 Diag((*DI)->getLocation(), diag::note_ambiguous_candidate) << *DI; 1257 1258 return true; 1259 } 1260 } 1261 1262 llvm_unreachable("unknown ambiguity kind"); 1263 return true; 1264} 1265 1266static void 1267addAssociatedClassesAndNamespaces(QualType T, 1268 ASTContext &Context, 1269 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1270 Sema::AssociatedClassSet &AssociatedClasses); 1271 1272static void CollectNamespace(Sema::AssociatedNamespaceSet &Namespaces, 1273 DeclContext *Ctx) { 1274 if (Ctx->isFileContext()) 1275 Namespaces.insert(Ctx); 1276} 1277 1278// \brief Add the associated classes and namespaces for argument-dependent 1279// lookup that involves a template argument (C++ [basic.lookup.koenig]p2). 1280static void 1281addAssociatedClassesAndNamespaces(const TemplateArgument &Arg, 1282 ASTContext &Context, 1283 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1284 Sema::AssociatedClassSet &AssociatedClasses) { 1285 // C++ [basic.lookup.koenig]p2, last bullet: 1286 // -- [...] ; 1287 switch (Arg.getKind()) { 1288 case TemplateArgument::Null: 1289 break; 1290 1291 case TemplateArgument::Type: 1292 // [...] the namespaces and classes associated with the types of the 1293 // template arguments provided for template type parameters (excluding 1294 // template template parameters) 1295 addAssociatedClassesAndNamespaces(Arg.getAsType(), Context, 1296 AssociatedNamespaces, 1297 AssociatedClasses); 1298 break; 1299 1300 case TemplateArgument::Template: { 1301 // [...] the namespaces in which any template template arguments are 1302 // defined; and the classes in which any member templates used as 1303 // template template arguments are defined. 1304 TemplateName Template = Arg.getAsTemplate(); 1305 if (ClassTemplateDecl *ClassTemplate 1306 = dyn_cast<ClassTemplateDecl>(Template.getAsTemplateDecl())) { 1307 DeclContext *Ctx = ClassTemplate->getDeclContext(); 1308 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1309 AssociatedClasses.insert(EnclosingClass); 1310 // Add the associated namespace for this class. 1311 while (Ctx->isRecord()) 1312 Ctx = Ctx->getParent(); 1313 CollectNamespace(AssociatedNamespaces, Ctx); 1314 } 1315 break; 1316 } 1317 1318 case TemplateArgument::Declaration: 1319 case TemplateArgument::Integral: 1320 case TemplateArgument::Expression: 1321 // [Note: non-type template arguments do not contribute to the set of 1322 // associated namespaces. ] 1323 break; 1324 1325 case TemplateArgument::Pack: 1326 for (TemplateArgument::pack_iterator P = Arg.pack_begin(), 1327 PEnd = Arg.pack_end(); 1328 P != PEnd; ++P) 1329 addAssociatedClassesAndNamespaces(*P, Context, 1330 AssociatedNamespaces, 1331 AssociatedClasses); 1332 break; 1333 } 1334} 1335 1336// \brief Add the associated classes and namespaces for 1337// argument-dependent lookup with an argument of class type 1338// (C++ [basic.lookup.koenig]p2). 1339static void 1340addAssociatedClassesAndNamespaces(CXXRecordDecl *Class, 1341 ASTContext &Context, 1342 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1343 Sema::AssociatedClassSet &AssociatedClasses) { 1344 // C++ [basic.lookup.koenig]p2: 1345 // [...] 1346 // -- If T is a class type (including unions), its associated 1347 // classes are: the class itself; the class of which it is a 1348 // member, if any; and its direct and indirect base 1349 // classes. Its associated namespaces are the namespaces in 1350 // which its associated classes are defined. 1351 1352 // Add the class of which it is a member, if any. 1353 DeclContext *Ctx = Class->getDeclContext(); 1354 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1355 AssociatedClasses.insert(EnclosingClass); 1356 // Add the associated namespace for this class. 1357 while (Ctx->isRecord()) 1358 Ctx = Ctx->getParent(); 1359 CollectNamespace(AssociatedNamespaces, Ctx); 1360 1361 // Add the class itself. If we've already seen this class, we don't 1362 // need to visit base classes. 1363 if (!AssociatedClasses.insert(Class)) 1364 return; 1365 1366 // -- If T is a template-id, its associated namespaces and classes are 1367 // the namespace in which the template is defined; for member 1368 // templates, the member template���s class; the namespaces and classes 1369 // associated with the types of the template arguments provided for 1370 // template type parameters (excluding template template parameters); the 1371 // namespaces in which any template template arguments are defined; and 1372 // the classes in which any member templates used as template template 1373 // arguments are defined. [Note: non-type template arguments do not 1374 // contribute to the set of associated namespaces. ] 1375 if (ClassTemplateSpecializationDecl *Spec 1376 = dyn_cast<ClassTemplateSpecializationDecl>(Class)) { 1377 DeclContext *Ctx = Spec->getSpecializedTemplate()->getDeclContext(); 1378 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1379 AssociatedClasses.insert(EnclosingClass); 1380 // Add the associated namespace for this class. 1381 while (Ctx->isRecord()) 1382 Ctx = Ctx->getParent(); 1383 CollectNamespace(AssociatedNamespaces, Ctx); 1384 1385 const TemplateArgumentList &TemplateArgs = Spec->getTemplateArgs(); 1386 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I) 1387 addAssociatedClassesAndNamespaces(TemplateArgs[I], Context, 1388 AssociatedNamespaces, 1389 AssociatedClasses); 1390 } 1391 1392 // Add direct and indirect base classes along with their associated 1393 // namespaces. 1394 llvm::SmallVector<CXXRecordDecl *, 32> Bases; 1395 Bases.push_back(Class); 1396 while (!Bases.empty()) { 1397 // Pop this class off the stack. 1398 Class = Bases.back(); 1399 Bases.pop_back(); 1400 1401 // Visit the base classes. 1402 for (CXXRecordDecl::base_class_iterator Base = Class->bases_begin(), 1403 BaseEnd = Class->bases_end(); 1404 Base != BaseEnd; ++Base) { 1405 const RecordType *BaseType = Base->getType()->getAs<RecordType>(); 1406 // In dependent contexts, we do ADL twice, and the first time around, 1407 // the base type might be a dependent TemplateSpecializationType, or a 1408 // TemplateTypeParmType. If that happens, simply ignore it. 1409 // FIXME: If we want to support export, we probably need to add the 1410 // namespace of the template in a TemplateSpecializationType, or even 1411 // the classes and namespaces of known non-dependent arguments. 1412 if (!BaseType) 1413 continue; 1414 CXXRecordDecl *BaseDecl = cast<CXXRecordDecl>(BaseType->getDecl()); 1415 if (AssociatedClasses.insert(BaseDecl)) { 1416 // Find the associated namespace for this base class. 1417 DeclContext *BaseCtx = BaseDecl->getDeclContext(); 1418 while (BaseCtx->isRecord()) 1419 BaseCtx = BaseCtx->getParent(); 1420 CollectNamespace(AssociatedNamespaces, BaseCtx); 1421 1422 // Make sure we visit the bases of this base class. 1423 if (BaseDecl->bases_begin() != BaseDecl->bases_end()) 1424 Bases.push_back(BaseDecl); 1425 } 1426 } 1427 } 1428} 1429 1430// \brief Add the associated classes and namespaces for 1431// argument-dependent lookup with an argument of type T 1432// (C++ [basic.lookup.koenig]p2). 1433static void 1434addAssociatedClassesAndNamespaces(QualType T, 1435 ASTContext &Context, 1436 Sema::AssociatedNamespaceSet &AssociatedNamespaces, 1437 Sema::AssociatedClassSet &AssociatedClasses) { 1438 // C++ [basic.lookup.koenig]p2: 1439 // 1440 // For each argument type T in the function call, there is a set 1441 // of zero or more associated namespaces and a set of zero or more 1442 // associated classes to be considered. The sets of namespaces and 1443 // classes is determined entirely by the types of the function 1444 // arguments (and the namespace of any template template 1445 // argument). Typedef names and using-declarations used to specify 1446 // the types do not contribute to this set. The sets of namespaces 1447 // and classes are determined in the following way: 1448 T = Context.getCanonicalType(T).getUnqualifiedType(); 1449 1450 // -- If T is a pointer to U or an array of U, its associated 1451 // namespaces and classes are those associated with U. 1452 // 1453 // We handle this by unwrapping pointer and array types immediately, 1454 // to avoid unnecessary recursion. 1455 while (true) { 1456 if (const PointerType *Ptr = T->getAs<PointerType>()) 1457 T = Ptr->getPointeeType(); 1458 else if (const ArrayType *Ptr = Context.getAsArrayType(T)) 1459 T = Ptr->getElementType(); 1460 else 1461 break; 1462 } 1463 1464 // -- If T is a fundamental type, its associated sets of 1465 // namespaces and classes are both empty. 1466 if (T->getAs<BuiltinType>()) 1467 return; 1468 1469 // -- If T is a class type (including unions), its associated 1470 // classes are: the class itself; the class of which it is a 1471 // member, if any; and its direct and indirect base 1472 // classes. Its associated namespaces are the namespaces in 1473 // which its associated classes are defined. 1474 if (const RecordType *ClassType = T->getAs<RecordType>()) 1475 if (CXXRecordDecl *ClassDecl 1476 = dyn_cast<CXXRecordDecl>(ClassType->getDecl())) { 1477 addAssociatedClassesAndNamespaces(ClassDecl, Context, 1478 AssociatedNamespaces, 1479 AssociatedClasses); 1480 return; 1481 } 1482 1483 // -- If T is an enumeration type, its associated namespace is 1484 // the namespace in which it is defined. If it is class 1485 // member, its associated class is the member���s class; else 1486 // it has no associated class. 1487 if (const EnumType *EnumT = T->getAs<EnumType>()) { 1488 EnumDecl *Enum = EnumT->getDecl(); 1489 1490 DeclContext *Ctx = Enum->getDeclContext(); 1491 if (CXXRecordDecl *EnclosingClass = dyn_cast<CXXRecordDecl>(Ctx)) 1492 AssociatedClasses.insert(EnclosingClass); 1493 1494 // Add the associated namespace for this class. 1495 while (Ctx->isRecord()) 1496 Ctx = Ctx->getParent(); 1497 CollectNamespace(AssociatedNamespaces, Ctx); 1498 1499 return; 1500 } 1501 1502 // -- If T is a function type, its associated namespaces and 1503 // classes are those associated with the function parameter 1504 // types and those associated with the return type. 1505 if (const FunctionType *FnType = T->getAs<FunctionType>()) { 1506 // Return type 1507 addAssociatedClassesAndNamespaces(FnType->getResultType(), 1508 Context, 1509 AssociatedNamespaces, AssociatedClasses); 1510 1511 const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FnType); 1512 if (!Proto) 1513 return; 1514 1515 // Argument types 1516 for (FunctionProtoType::arg_type_iterator Arg = Proto->arg_type_begin(), 1517 ArgEnd = Proto->arg_type_end(); 1518 Arg != ArgEnd; ++Arg) 1519 addAssociatedClassesAndNamespaces(*Arg, Context, 1520 AssociatedNamespaces, AssociatedClasses); 1521 1522 return; 1523 } 1524 1525 // -- If T is a pointer to a member function of a class X, its 1526 // associated namespaces and classes are those associated 1527 // with the function parameter types and return type, 1528 // together with those associated with X. 1529 // 1530 // -- If T is a pointer to a data member of class X, its 1531 // associated namespaces and classes are those associated 1532 // with the member type together with those associated with 1533 // X. 1534 if (const MemberPointerType *MemberPtr = T->getAs<MemberPointerType>()) { 1535 // Handle the type that the pointer to member points to. 1536 addAssociatedClassesAndNamespaces(MemberPtr->getPointeeType(), 1537 Context, 1538 AssociatedNamespaces, 1539 AssociatedClasses); 1540 1541 // Handle the class type into which this points. 1542 if (const RecordType *Class = MemberPtr->getClass()->getAs<RecordType>()) 1543 addAssociatedClassesAndNamespaces(cast<CXXRecordDecl>(Class->getDecl()), 1544 Context, 1545 AssociatedNamespaces, 1546 AssociatedClasses); 1547 1548 return; 1549 } 1550 1551 // FIXME: What about block pointers? 1552 // FIXME: What about Objective-C message sends? 1553} 1554 1555/// \brief Find the associated classes and namespaces for 1556/// argument-dependent lookup for a call with the given set of 1557/// arguments. 1558/// 1559/// This routine computes the sets of associated classes and associated 1560/// namespaces searched by argument-dependent lookup 1561/// (C++ [basic.lookup.argdep]) for a given set of arguments. 1562void 1563Sema::FindAssociatedClassesAndNamespaces(Expr **Args, unsigned NumArgs, 1564 AssociatedNamespaceSet &AssociatedNamespaces, 1565 AssociatedClassSet &AssociatedClasses) { 1566 AssociatedNamespaces.clear(); 1567 AssociatedClasses.clear(); 1568 1569 // C++ [basic.lookup.koenig]p2: 1570 // For each argument type T in the function call, there is a set 1571 // of zero or more associated namespaces and a set of zero or more 1572 // associated classes to be considered. The sets of namespaces and 1573 // classes is determined entirely by the types of the function 1574 // arguments (and the namespace of any template template 1575 // argument). 1576 for (unsigned ArgIdx = 0; ArgIdx != NumArgs; ++ArgIdx) { 1577 Expr *Arg = Args[ArgIdx]; 1578 1579 if (Arg->getType() != Context.OverloadTy) { 1580 addAssociatedClassesAndNamespaces(Arg->getType(), Context, 1581 AssociatedNamespaces, 1582 AssociatedClasses); 1583 continue; 1584 } 1585 1586 // [...] In addition, if the argument is the name or address of a 1587 // set of overloaded functions and/or function templates, its 1588 // associated classes and namespaces are the union of those 1589 // associated with each of the members of the set: the namespace 1590 // in which the function or function template is defined and the 1591 // classes and namespaces associated with its (non-dependent) 1592 // parameter types and return type. 1593 Arg = Arg->IgnoreParens(); 1594 if (UnaryOperator *unaryOp = dyn_cast<UnaryOperator>(Arg)) 1595 if (unaryOp->getOpcode() == UnaryOperator::AddrOf) 1596 Arg = unaryOp->getSubExpr(); 1597 1598 // TODO: avoid the copies. This should be easy when the cases 1599 // share a storage implementation. 1600 llvm::SmallVector<NamedDecl*, 8> Functions; 1601 1602 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(Arg)) 1603 Functions.append(ULE->decls_begin(), ULE->decls_end()); 1604 else 1605 continue; 1606 1607 for (llvm::SmallVectorImpl<NamedDecl*>::iterator I = Functions.begin(), 1608 E = Functions.end(); I != E; ++I) { 1609 // Look through any using declarations to find the underlying function. 1610 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 1611 1612 FunctionDecl *FDecl = dyn_cast<FunctionDecl>(Fn); 1613 if (!FDecl) 1614 FDecl = cast<FunctionTemplateDecl>(Fn)->getTemplatedDecl(); 1615 1616 // Add the classes and namespaces associated with the parameter 1617 // types and return type of this function. 1618 addAssociatedClassesAndNamespaces(FDecl->getType(), Context, 1619 AssociatedNamespaces, 1620 AssociatedClasses); 1621 } 1622 } 1623} 1624 1625/// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is 1626/// an acceptable non-member overloaded operator for a call whose 1627/// arguments have types T1 (and, if non-empty, T2). This routine 1628/// implements the check in C++ [over.match.oper]p3b2 concerning 1629/// enumeration types. 1630static bool 1631IsAcceptableNonMemberOperatorCandidate(FunctionDecl *Fn, 1632 QualType T1, QualType T2, 1633 ASTContext &Context) { 1634 if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType())) 1635 return true; 1636 1637 if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType())) 1638 return true; 1639 1640 const FunctionProtoType *Proto = Fn->getType()->getAs<FunctionProtoType>(); 1641 if (Proto->getNumArgs() < 1) 1642 return false; 1643 1644 if (T1->isEnumeralType()) { 1645 QualType ArgType = Proto->getArgType(0).getNonReferenceType(); 1646 if (Context.hasSameUnqualifiedType(T1, ArgType)) 1647 return true; 1648 } 1649 1650 if (Proto->getNumArgs() < 2) 1651 return false; 1652 1653 if (!T2.isNull() && T2->isEnumeralType()) { 1654 QualType ArgType = Proto->getArgType(1).getNonReferenceType(); 1655 if (Context.hasSameUnqualifiedType(T2, ArgType)) 1656 return true; 1657 } 1658 1659 return false; 1660} 1661 1662NamedDecl *Sema::LookupSingleName(Scope *S, DeclarationName Name, 1663 LookupNameKind NameKind, 1664 RedeclarationKind Redecl) { 1665 LookupResult R(*this, Name, SourceLocation(), NameKind, Redecl); 1666 LookupName(R, S); 1667 return R.getAsSingle<NamedDecl>(); 1668} 1669 1670/// \brief Find the protocol with the given name, if any. 1671ObjCProtocolDecl *Sema::LookupProtocol(IdentifierInfo *II) { 1672 Decl *D = LookupSingleName(TUScope, II, LookupObjCProtocolName); 1673 return cast_or_null<ObjCProtocolDecl>(D); 1674} 1675 1676void Sema::LookupOverloadedOperatorName(OverloadedOperatorKind Op, Scope *S, 1677 QualType T1, QualType T2, 1678 FunctionSet &Functions) { 1679 // C++ [over.match.oper]p3: 1680 // -- The set of non-member candidates is the result of the 1681 // unqualified lookup of operator@ in the context of the 1682 // expression according to the usual rules for name lookup in 1683 // unqualified function calls (3.4.2) except that all member 1684 // functions are ignored. However, if no operand has a class 1685 // type, only those non-member functions in the lookup set 1686 // that have a first parameter of type T1 or "reference to 1687 // (possibly cv-qualified) T1", when T1 is an enumeration 1688 // type, or (if there is a right operand) a second parameter 1689 // of type T2 or "reference to (possibly cv-qualified) T2", 1690 // when T2 is an enumeration type, are candidate functions. 1691 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 1692 LookupResult Operators(*this, OpName, SourceLocation(), LookupOperatorName); 1693 LookupName(Operators, S); 1694 1695 assert(!Operators.isAmbiguous() && "Operator lookup cannot be ambiguous"); 1696 1697 if (Operators.empty()) 1698 return; 1699 1700 for (LookupResult::iterator Op = Operators.begin(), OpEnd = Operators.end(); 1701 Op != OpEnd; ++Op) { 1702 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*Op)) { 1703 if (IsAcceptableNonMemberOperatorCandidate(FD, T1, T2, Context)) 1704 Functions.insert(FD); // FIXME: canonical FD 1705 } else if (FunctionTemplateDecl *FunTmpl 1706 = dyn_cast<FunctionTemplateDecl>(*Op)) { 1707 // FIXME: friend operators? 1708 // FIXME: do we need to check IsAcceptableNonMemberOperatorCandidate, 1709 // later? 1710 if (!FunTmpl->getDeclContext()->isRecord()) 1711 Functions.insert(FunTmpl); 1712 } 1713 } 1714} 1715 1716static void CollectFunctionDecl(Sema::FunctionSet &Functions, 1717 Decl *D) { 1718 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(D)) 1719 Functions.insert(Func); 1720 else if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) 1721 Functions.insert(FunTmpl); 1722} 1723 1724void Sema::ArgumentDependentLookup(DeclarationName Name, bool Operator, 1725 Expr **Args, unsigned NumArgs, 1726 FunctionSet &Functions) { 1727 // Find all of the associated namespaces and classes based on the 1728 // arguments we have. 1729 AssociatedNamespaceSet AssociatedNamespaces; 1730 AssociatedClassSet AssociatedClasses; 1731 FindAssociatedClassesAndNamespaces(Args, NumArgs, 1732 AssociatedNamespaces, 1733 AssociatedClasses); 1734 1735 QualType T1, T2; 1736 if (Operator) { 1737 T1 = Args[0]->getType(); 1738 if (NumArgs >= 2) 1739 T2 = Args[1]->getType(); 1740 } 1741 1742 // C++ [basic.lookup.argdep]p3: 1743 // Let X be the lookup set produced by unqualified lookup (3.4.1) 1744 // and let Y be the lookup set produced by argument dependent 1745 // lookup (defined as follows). If X contains [...] then Y is 1746 // empty. Otherwise Y is the set of declarations found in the 1747 // namespaces associated with the argument types as described 1748 // below. The set of declarations found by the lookup of the name 1749 // is the union of X and Y. 1750 // 1751 // Here, we compute Y and add its members to the overloaded 1752 // candidate set. 1753 for (AssociatedNamespaceSet::iterator NS = AssociatedNamespaces.begin(), 1754 NSEnd = AssociatedNamespaces.end(); 1755 NS != NSEnd; ++NS) { 1756 // When considering an associated namespace, the lookup is the 1757 // same as the lookup performed when the associated namespace is 1758 // used as a qualifier (3.4.3.2) except that: 1759 // 1760 // -- Any using-directives in the associated namespace are 1761 // ignored. 1762 // 1763 // -- Any namespace-scope friend functions declared in 1764 // associated classes are visible within their respective 1765 // namespaces even if they are not visible during an ordinary 1766 // lookup (11.4). 1767 DeclContext::lookup_iterator I, E; 1768 for (llvm::tie(I, E) = (*NS)->lookup(Name); I != E; ++I) { 1769 Decl *D = *I; 1770 // If the only declaration here is an ordinary friend, consider 1771 // it only if it was declared in an associated classes. 1772 if (D->getIdentifierNamespace() == Decl::IDNS_OrdinaryFriend) { 1773 DeclContext *LexDC = D->getLexicalDeclContext(); 1774 if (!AssociatedClasses.count(cast<CXXRecordDecl>(LexDC))) 1775 continue; 1776 } 1777 1778 FunctionDecl *Fn; 1779 if (!Operator || !(Fn = dyn_cast<FunctionDecl>(D)) || 1780 IsAcceptableNonMemberOperatorCandidate(Fn, T1, T2, Context)) 1781 CollectFunctionDecl(Functions, D); 1782 } 1783 } 1784} 1785 1786//---------------------------------------------------------------------------- 1787// Search for all visible declarations. 1788//---------------------------------------------------------------------------- 1789VisibleDeclConsumer::~VisibleDeclConsumer() { } 1790 1791namespace { 1792 1793class ShadowContextRAII; 1794 1795class VisibleDeclsRecord { 1796public: 1797 /// \brief An entry in the shadow map, which is optimized to store a 1798 /// single declaration (the common case) but can also store a list 1799 /// of declarations. 1800 class ShadowMapEntry { 1801 typedef llvm::SmallVector<NamedDecl *, 4> DeclVector; 1802 1803 /// \brief Contains either the solitary NamedDecl * or a vector 1804 /// of declarations. 1805 llvm::PointerUnion<NamedDecl *, DeclVector*> DeclOrVector; 1806 1807 public: 1808 ShadowMapEntry() : DeclOrVector() { } 1809 1810 void Add(NamedDecl *ND); 1811 void Destroy(); 1812 1813 // Iteration. 1814 typedef NamedDecl **iterator; 1815 iterator begin(); 1816 iterator end(); 1817 }; 1818 1819private: 1820 /// \brief A mapping from declaration names to the declarations that have 1821 /// this name within a particular scope. 1822 typedef llvm::DenseMap<DeclarationName, ShadowMapEntry> ShadowMap; 1823 1824 /// \brief A list of shadow maps, which is used to model name hiding. 1825 std::list<ShadowMap> ShadowMaps; 1826 1827 /// \brief The declaration contexts we have already visited. 1828 llvm::SmallPtrSet<DeclContext *, 8> VisitedContexts; 1829 1830 friend class ShadowContextRAII; 1831 1832public: 1833 /// \brief Determine whether we have already visited this context 1834 /// (and, if not, note that we are going to visit that context now). 1835 bool visitedContext(DeclContext *Ctx) { 1836 return !VisitedContexts.insert(Ctx); 1837 } 1838 1839 /// \brief Determine whether the given declaration is hidden in the 1840 /// current scope. 1841 /// 1842 /// \returns the declaration that hides the given declaration, or 1843 /// NULL if no such declaration exists. 1844 NamedDecl *checkHidden(NamedDecl *ND); 1845 1846 /// \brief Add a declaration to the current shadow map. 1847 void add(NamedDecl *ND) { ShadowMaps.back()[ND->getDeclName()].Add(ND); } 1848}; 1849 1850/// \brief RAII object that records when we've entered a shadow context. 1851class ShadowContextRAII { 1852 VisibleDeclsRecord &Visible; 1853 1854 typedef VisibleDeclsRecord::ShadowMap ShadowMap; 1855 1856public: 1857 ShadowContextRAII(VisibleDeclsRecord &Visible) : Visible(Visible) { 1858 Visible.ShadowMaps.push_back(ShadowMap()); 1859 } 1860 1861 ~ShadowContextRAII() { 1862 for (ShadowMap::iterator E = Visible.ShadowMaps.back().begin(), 1863 EEnd = Visible.ShadowMaps.back().end(); 1864 E != EEnd; 1865 ++E) 1866 E->second.Destroy(); 1867 1868 Visible.ShadowMaps.pop_back(); 1869 } 1870}; 1871 1872} // end anonymous namespace 1873 1874void VisibleDeclsRecord::ShadowMapEntry::Add(NamedDecl *ND) { 1875 if (DeclOrVector.isNull()) { 1876 // 0 - > 1 elements: just set the single element information. 1877 DeclOrVector = ND; 1878 return; 1879 } 1880 1881 if (NamedDecl *PrevND = DeclOrVector.dyn_cast<NamedDecl *>()) { 1882 // 1 -> 2 elements: create the vector of results and push in the 1883 // existing declaration. 1884 DeclVector *Vec = new DeclVector; 1885 Vec->push_back(PrevND); 1886 DeclOrVector = Vec; 1887 } 1888 1889 // Add the new element to the end of the vector. 1890 DeclOrVector.get<DeclVector*>()->push_back(ND); 1891} 1892 1893void VisibleDeclsRecord::ShadowMapEntry::Destroy() { 1894 if (DeclVector *Vec = DeclOrVector.dyn_cast<DeclVector *>()) { 1895 delete Vec; 1896 DeclOrVector = ((NamedDecl *)0); 1897 } 1898} 1899 1900VisibleDeclsRecord::ShadowMapEntry::iterator 1901VisibleDeclsRecord::ShadowMapEntry::begin() { 1902 if (DeclOrVector.isNull()) 1903 return 0; 1904 1905 if (DeclOrVector.dyn_cast<NamedDecl *>()) 1906 return &reinterpret_cast<NamedDecl*&>(DeclOrVector); 1907 1908 return DeclOrVector.get<DeclVector *>()->begin(); 1909} 1910 1911VisibleDeclsRecord::ShadowMapEntry::iterator 1912VisibleDeclsRecord::ShadowMapEntry::end() { 1913 if (DeclOrVector.isNull()) 1914 return 0; 1915 1916 if (DeclOrVector.dyn_cast<NamedDecl *>()) 1917 return &reinterpret_cast<NamedDecl*&>(DeclOrVector) + 1; 1918 1919 return DeclOrVector.get<DeclVector *>()->end(); 1920} 1921 1922NamedDecl *VisibleDeclsRecord::checkHidden(NamedDecl *ND) { 1923 // Look through using declarations. 1924 ND = ND->getUnderlyingDecl(); 1925 1926 unsigned IDNS = ND->getIdentifierNamespace(); 1927 std::list<ShadowMap>::reverse_iterator SM = ShadowMaps.rbegin(); 1928 for (std::list<ShadowMap>::reverse_iterator SMEnd = ShadowMaps.rend(); 1929 SM != SMEnd; ++SM) { 1930 ShadowMap::iterator Pos = SM->find(ND->getDeclName()); 1931 if (Pos == SM->end()) 1932 continue; 1933 1934 for (ShadowMapEntry::iterator I = Pos->second.begin(), 1935 IEnd = Pos->second.end(); 1936 I != IEnd; ++I) { 1937 // A tag declaration does not hide a non-tag declaration. 1938 if ((*I)->getIdentifierNamespace() == Decl::IDNS_Tag && 1939 (IDNS & (Decl::IDNS_Member | Decl::IDNS_Ordinary | 1940 Decl::IDNS_ObjCProtocol))) 1941 continue; 1942 1943 // Protocols are in distinct namespaces from everything else. 1944 if ((((*I)->getIdentifierNamespace() & Decl::IDNS_ObjCProtocol) 1945 || (IDNS & Decl::IDNS_ObjCProtocol)) && 1946 (*I)->getIdentifierNamespace() != IDNS) 1947 continue; 1948 1949 // Functions and function templates in the same scope overload 1950 // rather than hide. FIXME: Look for hiding based on function 1951 // signatures! 1952 if ((*I)->isFunctionOrFunctionTemplate() && 1953 ND->isFunctionOrFunctionTemplate() && 1954 SM == ShadowMaps.rbegin()) 1955 continue; 1956 1957 // We've found a declaration that hides this one. 1958 return *I; 1959 } 1960 } 1961 1962 return 0; 1963} 1964 1965static void LookupVisibleDecls(DeclContext *Ctx, LookupResult &Result, 1966 bool QualifiedNameLookup, 1967 bool InBaseClass, 1968 VisibleDeclConsumer &Consumer, 1969 VisibleDeclsRecord &Visited) { 1970 // Make sure we don't visit the same context twice. 1971 if (Visited.visitedContext(Ctx->getPrimaryContext())) 1972 return; 1973 1974 // Enumerate all of the results in this context. 1975 for (DeclContext *CurCtx = Ctx->getPrimaryContext(); CurCtx; 1976 CurCtx = CurCtx->getNextContext()) { 1977 for (DeclContext::decl_iterator D = CurCtx->decls_begin(), 1978 DEnd = CurCtx->decls_end(); 1979 D != DEnd; ++D) { 1980 if (NamedDecl *ND = dyn_cast<NamedDecl>(*D)) 1981 if (Result.isAcceptableDecl(ND)) { 1982 Consumer.FoundDecl(ND, Visited.checkHidden(ND), InBaseClass); 1983 Visited.add(ND); 1984 } 1985 1986 // Visit transparent contexts inside this context. 1987 if (DeclContext *InnerCtx = dyn_cast<DeclContext>(*D)) { 1988 if (InnerCtx->isTransparentContext()) 1989 LookupVisibleDecls(InnerCtx, Result, QualifiedNameLookup, InBaseClass, 1990 Consumer, Visited); 1991 } 1992 } 1993 } 1994 1995 // Traverse using directives for qualified name lookup. 1996 if (QualifiedNameLookup) { 1997 ShadowContextRAII Shadow(Visited); 1998 DeclContext::udir_iterator I, E; 1999 for (llvm::tie(I, E) = Ctx->getUsingDirectives(); I != E; ++I) { 2000 LookupVisibleDecls((*I)->getNominatedNamespace(), Result, 2001 QualifiedNameLookup, InBaseClass, Consumer, Visited); 2002 } 2003 } 2004 2005 // Traverse the contexts of inherited C++ classes. 2006 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx)) { 2007 for (CXXRecordDecl::base_class_iterator B = Record->bases_begin(), 2008 BEnd = Record->bases_end(); 2009 B != BEnd; ++B) { 2010 QualType BaseType = B->getType(); 2011 2012 // Don't look into dependent bases, because name lookup can't look 2013 // there anyway. 2014 if (BaseType->isDependentType()) 2015 continue; 2016 2017 const RecordType *Record = BaseType->getAs<RecordType>(); 2018 if (!Record) 2019 continue; 2020 2021 // FIXME: It would be nice to be able to determine whether referencing 2022 // a particular member would be ambiguous. For example, given 2023 // 2024 // struct A { int member; }; 2025 // struct B { int member; }; 2026 // struct C : A, B { }; 2027 // 2028 // void f(C *c) { c->### } 2029 // 2030 // accessing 'member' would result in an ambiguity. However, we 2031 // could be smart enough to qualify the member with the base 2032 // class, e.g., 2033 // 2034 // c->B::member 2035 // 2036 // or 2037 // 2038 // c->A::member 2039 2040 // Find results in this base class (and its bases). 2041 ShadowContextRAII Shadow(Visited); 2042 LookupVisibleDecls(Record->getDecl(), Result, QualifiedNameLookup, 2043 true, Consumer, Visited); 2044 } 2045 } 2046 2047 // Traverse the contexts of Objective-C classes. 2048 if (ObjCInterfaceDecl *IFace = dyn_cast<ObjCInterfaceDecl>(Ctx)) { 2049 // Traverse categories. 2050 for (ObjCCategoryDecl *Category = IFace->getCategoryList(); 2051 Category; Category = Category->getNextClassCategory()) { 2052 ShadowContextRAII Shadow(Visited); 2053 LookupVisibleDecls(Category, Result, QualifiedNameLookup, false, 2054 Consumer, Visited); 2055 } 2056 2057 // Traverse protocols. 2058 for (ObjCInterfaceDecl::protocol_iterator I = IFace->protocol_begin(), 2059 E = IFace->protocol_end(); I != E; ++I) { 2060 ShadowContextRAII Shadow(Visited); 2061 LookupVisibleDecls(*I, Result, QualifiedNameLookup, false, Consumer, 2062 Visited); 2063 } 2064 2065 // Traverse the superclass. 2066 if (IFace->getSuperClass()) { 2067 ShadowContextRAII Shadow(Visited); 2068 LookupVisibleDecls(IFace->getSuperClass(), Result, QualifiedNameLookup, 2069 true, Consumer, Visited); 2070 } 2071 } else if (ObjCProtocolDecl *Protocol = dyn_cast<ObjCProtocolDecl>(Ctx)) { 2072 for (ObjCProtocolDecl::protocol_iterator I = Protocol->protocol_begin(), 2073 E = Protocol->protocol_end(); I != E; ++I) { 2074 ShadowContextRAII Shadow(Visited); 2075 LookupVisibleDecls(*I, Result, QualifiedNameLookup, false, Consumer, 2076 Visited); 2077 } 2078 } else if (ObjCCategoryDecl *Category = dyn_cast<ObjCCategoryDecl>(Ctx)) { 2079 for (ObjCCategoryDecl::protocol_iterator I = Category->protocol_begin(), 2080 E = Category->protocol_end(); I != E; ++I) { 2081 ShadowContextRAII Shadow(Visited); 2082 LookupVisibleDecls(*I, Result, QualifiedNameLookup, false, Consumer, 2083 Visited); 2084 } 2085 } 2086} 2087 2088static void LookupVisibleDecls(Scope *S, LookupResult &Result, 2089 UnqualUsingDirectiveSet &UDirs, 2090 VisibleDeclConsumer &Consumer, 2091 VisibleDeclsRecord &Visited) { 2092 if (!S) 2093 return; 2094 2095 if (!S->getEntity() || !S->getParent() || 2096 ((DeclContext *)S->getEntity())->isFunctionOrMethod()) { 2097 // Walk through the declarations in this Scope. 2098 for (Scope::decl_iterator D = S->decl_begin(), DEnd = S->decl_end(); 2099 D != DEnd; ++D) { 2100 if (NamedDecl *ND = dyn_cast<NamedDecl>((Decl *)((*D).get()))) 2101 if (Result.isAcceptableDecl(ND)) { 2102 Consumer.FoundDecl(ND, Visited.checkHidden(ND), false); 2103 Visited.add(ND); 2104 } 2105 } 2106 } 2107 2108 DeclContext *Entity = 0; 2109 if (S->getEntity()) { 2110 // Look into this scope's declaration context, along with any of its 2111 // parent lookup contexts (e.g., enclosing classes), up to the point 2112 // where we hit the context stored in the next outer scope. 2113 Entity = (DeclContext *)S->getEntity(); 2114 DeclContext *OuterCtx = findOuterContext(S); 2115 2116 for (DeclContext *Ctx = Entity; Ctx && Ctx->getPrimaryContext() != OuterCtx; 2117 Ctx = Ctx->getLookupParent()) { 2118 if (ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(Ctx)) { 2119 if (Method->isInstanceMethod()) { 2120 // For instance methods, look for ivars in the method's interface. 2121 LookupResult IvarResult(Result.getSema(), Result.getLookupName(), 2122 Result.getNameLoc(), Sema::LookupMemberName); 2123 ObjCInterfaceDecl *IFace = Method->getClassInterface(); 2124 LookupVisibleDecls(IFace, IvarResult, /*QualifiedNameLookup=*/false, 2125 /*InBaseClass=*/false, Consumer, Visited); 2126 } 2127 2128 // We've already performed all of the name lookup that we need 2129 // to for Objective-C methods; the next context will be the 2130 // outer scope. 2131 break; 2132 } 2133 2134 if (Ctx->isFunctionOrMethod()) 2135 continue; 2136 2137 LookupVisibleDecls(Ctx, Result, /*QualifiedNameLookup=*/false, 2138 /*InBaseClass=*/false, Consumer, Visited); 2139 } 2140 } else if (!S->getParent()) { 2141 // Look into the translation unit scope. We walk through the translation 2142 // unit's declaration context, because the Scope itself won't have all of 2143 // the declarations if we loaded a precompiled header. 2144 // FIXME: We would like the translation unit's Scope object to point to the 2145 // translation unit, so we don't need this special "if" branch. However, 2146 // doing so would force the normal C++ name-lookup code to look into the 2147 // translation unit decl when the IdentifierInfo chains would suffice. 2148 // Once we fix that problem (which is part of a more general "don't look 2149 // in DeclContexts unless we have to" optimization), we can eliminate this. 2150 Entity = Result.getSema().Context.getTranslationUnitDecl(); 2151 LookupVisibleDecls(Entity, Result, /*QualifiedNameLookup=*/false, 2152 /*InBaseClass=*/false, Consumer, Visited); 2153 } 2154 2155 if (Entity) { 2156 // Lookup visible declarations in any namespaces found by using 2157 // directives. 2158 UnqualUsingDirectiveSet::const_iterator UI, UEnd; 2159 llvm::tie(UI, UEnd) = UDirs.getNamespacesFor(Entity); 2160 for (; UI != UEnd; ++UI) 2161 LookupVisibleDecls(const_cast<DeclContext *>(UI->getNominatedNamespace()), 2162 Result, /*QualifiedNameLookup=*/false, 2163 /*InBaseClass=*/false, Consumer, Visited); 2164 } 2165 2166 // Lookup names in the parent scope. 2167 ShadowContextRAII Shadow(Visited); 2168 LookupVisibleDecls(S->getParent(), Result, UDirs, Consumer, Visited); 2169} 2170 2171void Sema::LookupVisibleDecls(Scope *S, LookupNameKind Kind, 2172 VisibleDeclConsumer &Consumer) { 2173 // Determine the set of using directives available during 2174 // unqualified name lookup. 2175 Scope *Initial = S; 2176 UnqualUsingDirectiveSet UDirs; 2177 if (getLangOptions().CPlusPlus) { 2178 // Find the first namespace or translation-unit scope. 2179 while (S && !isNamespaceOrTranslationUnitScope(S)) 2180 S = S->getParent(); 2181 2182 UDirs.visitScopeChain(Initial, S); 2183 } 2184 UDirs.done(); 2185 2186 // Look for visible declarations. 2187 LookupResult Result(*this, DeclarationName(), SourceLocation(), Kind); 2188 VisibleDeclsRecord Visited; 2189 ShadowContextRAII Shadow(Visited); 2190 ::LookupVisibleDecls(Initial, Result, UDirs, Consumer, Visited); 2191} 2192 2193void Sema::LookupVisibleDecls(DeclContext *Ctx, LookupNameKind Kind, 2194 VisibleDeclConsumer &Consumer) { 2195 LookupResult Result(*this, DeclarationName(), SourceLocation(), Kind); 2196 VisibleDeclsRecord Visited; 2197 ShadowContextRAII Shadow(Visited); 2198 ::LookupVisibleDecls(Ctx, Result, /*QualifiedNameLookup=*/true, 2199 /*InBaseClass=*/false, Consumer, Visited); 2200} 2201 2202//---------------------------------------------------------------------------- 2203// Typo correction 2204//---------------------------------------------------------------------------- 2205 2206namespace { 2207class TypoCorrectionConsumer : public VisibleDeclConsumer { 2208 /// \brief The name written that is a typo in the source. 2209 llvm::StringRef Typo; 2210 2211 /// \brief The results found that have the smallest edit distance 2212 /// found (so far) with the typo name. 2213 llvm::SmallVector<NamedDecl *, 4> BestResults; 2214 2215 /// \brief The best edit distance found so far. 2216 unsigned BestEditDistance; 2217 2218public: 2219 explicit TypoCorrectionConsumer(IdentifierInfo *Typo) 2220 : Typo(Typo->getName()) { } 2221 2222 virtual void FoundDecl(NamedDecl *ND, NamedDecl *Hiding, bool InBaseClass); 2223 2224 typedef llvm::SmallVector<NamedDecl *, 4>::const_iterator iterator; 2225 iterator begin() const { return BestResults.begin(); } 2226 iterator end() const { return BestResults.end(); } 2227 bool empty() const { return BestResults.empty(); } 2228 2229 unsigned getBestEditDistance() const { return BestEditDistance; } 2230}; 2231 2232} 2233 2234void TypoCorrectionConsumer::FoundDecl(NamedDecl *ND, NamedDecl *Hiding, 2235 bool InBaseClass) { 2236 // Don't consider hidden names for typo correction. 2237 if (Hiding) 2238 return; 2239 2240 // Only consider entities with identifiers for names, ignoring 2241 // special names (constructors, overloaded operators, selectors, 2242 // etc.). 2243 IdentifierInfo *Name = ND->getIdentifier(); 2244 if (!Name) 2245 return; 2246 2247 // Compute the edit distance between the typo and the name of this 2248 // entity. If this edit distance is not worse than the best edit 2249 // distance we've seen so far, add it to the list of results. 2250 unsigned ED = Typo.edit_distance(Name->getName()); 2251 if (!BestResults.empty()) { 2252 if (ED < BestEditDistance) { 2253 // This result is better than any we've seen before; clear out 2254 // the previous results. 2255 BestResults.clear(); 2256 BestEditDistance = ED; 2257 } else if (ED > BestEditDistance) { 2258 // This result is worse than the best results we've seen so far; 2259 // ignore it. 2260 return; 2261 } 2262 } else 2263 BestEditDistance = ED; 2264 2265 BestResults.push_back(ND); 2266} 2267 2268/// \brief Try to "correct" a typo in the source code by finding 2269/// visible declarations whose names are similar to the name that was 2270/// present in the source code. 2271/// 2272/// \param Res the \c LookupResult structure that contains the name 2273/// that was present in the source code along with the name-lookup 2274/// criteria used to search for the name. On success, this structure 2275/// will contain the results of name lookup. 2276/// 2277/// \param S the scope in which name lookup occurs. 2278/// 2279/// \param SS the nested-name-specifier that precedes the name we're 2280/// looking for, if present. 2281/// 2282/// \param MemberContext if non-NULL, the context in which to look for 2283/// a member access expression. 2284/// 2285/// \param EnteringContext whether we're entering the context described by 2286/// the nested-name-specifier SS. 2287/// 2288/// \param OPT when non-NULL, the search for visible declarations will 2289/// also walk the protocols in the qualified interfaces of \p OPT. 2290/// 2291/// \returns true if the typo was corrected, in which case the \p Res 2292/// structure will contain the results of name lookup for the 2293/// corrected name. Otherwise, returns false. 2294bool Sema::CorrectTypo(LookupResult &Res, Scope *S, const CXXScopeSpec *SS, 2295 DeclContext *MemberContext, bool EnteringContext, 2296 const ObjCObjectPointerType *OPT) { 2297 2298 if (Diags.hasFatalErrorOccurred()) 2299 return false; 2300 2301 // We only attempt to correct typos for identifiers. 2302 IdentifierInfo *Typo = Res.getLookupName().getAsIdentifierInfo(); 2303 if (!Typo) 2304 return false; 2305 2306 // If the scope specifier itself was invalid, don't try to correct 2307 // typos. 2308 if (SS && SS->isInvalid()) 2309 return false; 2310 2311 // Never try to correct typos during template deduction or 2312 // instantiation. 2313 if (!ActiveTemplateInstantiations.empty()) 2314 return false; 2315 2316 TypoCorrectionConsumer Consumer(Typo); 2317 if (MemberContext) { 2318 LookupVisibleDecls(MemberContext, Res.getLookupKind(), Consumer); 2319 2320 // Look in qualified interfaces. 2321 if (OPT) { 2322 for (ObjCObjectPointerType::qual_iterator 2323 I = OPT->qual_begin(), E = OPT->qual_end(); 2324 I != E; ++I) 2325 LookupVisibleDecls(*I, Res.getLookupKind(), Consumer); 2326 } 2327 } else if (SS && SS->isSet()) { 2328 DeclContext *DC = computeDeclContext(*SS, EnteringContext); 2329 if (!DC) 2330 return false; 2331 2332 LookupVisibleDecls(DC, Res.getLookupKind(), Consumer); 2333 } else { 2334 LookupVisibleDecls(S, Res.getLookupKind(), Consumer); 2335 } 2336 2337 if (Consumer.empty()) 2338 return false; 2339 2340 // Only allow a single, closest name in the result set (it's okay to 2341 // have overloads of that name, though). 2342 TypoCorrectionConsumer::iterator I = Consumer.begin(); 2343 DeclarationName BestName = (*I)->getDeclName(); 2344 2345 // If we've found an Objective-C ivar or property, don't perform 2346 // name lookup again; we'll just return the result directly. 2347 NamedDecl *FoundBest = 0; 2348 if (isa<ObjCIvarDecl>(*I) || isa<ObjCPropertyDecl>(*I)) 2349 FoundBest = *I; 2350 ++I; 2351 for(TypoCorrectionConsumer::iterator IEnd = Consumer.end(); I != IEnd; ++I) { 2352 if (BestName != (*I)->getDeclName()) 2353 return false; 2354 2355 // FIXME: If there are both ivars and properties of the same name, 2356 // don't return both because the callee can't handle two 2357 // results. We really need to separate ivar lookup from property 2358 // lookup to avoid this problem. 2359 FoundBest = 0; 2360 } 2361 2362 // BestName is the closest viable name to what the user 2363 // typed. However, to make sure that we don't pick something that's 2364 // way off, make sure that the user typed at least 3 characters for 2365 // each correction. 2366 unsigned ED = Consumer.getBestEditDistance(); 2367 if (ED == 0 || (BestName.getAsIdentifierInfo()->getName().size() / ED) < 3) 2368 return false; 2369 2370 // Perform name lookup again with the name we chose, and declare 2371 // success if we found something that was not ambiguous. 2372 Res.clear(); 2373 Res.setLookupName(BestName); 2374 2375 // If we found an ivar or property, add that result; no further 2376 // lookup is required. 2377 if (FoundBest) 2378 Res.addDecl(FoundBest); 2379 // If we're looking into the context of a member, perform qualified 2380 // name lookup on the best name. 2381 else if (MemberContext) 2382 LookupQualifiedName(Res, MemberContext); 2383 // Perform lookup as if we had just parsed the best name. 2384 else 2385 LookupParsedName(Res, S, SS, /*AllowBuiltinCreation=*/false, 2386 EnteringContext); 2387 2388 if (Res.isAmbiguous()) { 2389 Res.suppressDiagnostics(); 2390 return false; 2391 } 2392 2393 return Res.getResultKind() != LookupResult::NotFound; 2394} 2395