SemaDeclCXX.cpp revision f70bdb9463a6e3ea2c6307b2c7a5f3e2c6b7e489
1//===------ SemaDeclCXX.cpp - Semantic Analysis for C++ Declarations ------===// 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 semantic analysis for C++ declarations. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Sema.h" 15#include "clang/AST/ASTConsumer.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/TypeOrdering.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/Lex/Preprocessor.h" 20#include "clang/Basic/Diagnostic.h" 21#include "clang/Parse/DeclSpec.h" 22#include "llvm/Support/Compiler.h" 23#include <algorithm> // for std::equal 24#include <map> 25 26using namespace clang; 27 28//===----------------------------------------------------------------------===// 29// CheckDefaultArgumentVisitor 30//===----------------------------------------------------------------------===// 31 32namespace { 33 /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses 34 /// the default argument of a parameter to determine whether it 35 /// contains any ill-formed subexpressions. For example, this will 36 /// diagnose the use of local variables or parameters within the 37 /// default argument expression. 38 class VISIBILITY_HIDDEN CheckDefaultArgumentVisitor 39 : public StmtVisitor<CheckDefaultArgumentVisitor, bool> { 40 Expr *DefaultArg; 41 Sema *S; 42 43 public: 44 CheckDefaultArgumentVisitor(Expr *defarg, Sema *s) 45 : DefaultArg(defarg), S(s) {} 46 47 bool VisitExpr(Expr *Node); 48 bool VisitDeclRefExpr(DeclRefExpr *DRE); 49 }; 50 51 /// VisitExpr - Visit all of the children of this expression. 52 bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) { 53 bool IsInvalid = false; 54 for (Stmt::child_iterator I = Node->child_begin(), 55 E = Node->child_end(); I != E; ++I) 56 IsInvalid |= Visit(*I); 57 return IsInvalid; 58 } 59 60 /// VisitDeclRefExpr - Visit a reference to a declaration, to 61 /// determine whether this declaration can be used in the default 62 /// argument expression. 63 bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) { 64 NamedDecl *Decl = DRE->getDecl(); 65 if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) { 66 // C++ [dcl.fct.default]p9 67 // Default arguments are evaluated each time the function is 68 // called. The order of evaluation of function arguments is 69 // unspecified. Consequently, parameters of a function shall not 70 // be used in default argument expressions, even if they are not 71 // evaluated. Parameters of a function declared before a default 72 // argument expression are in scope and can hide namespace and 73 // class member names. 74 return S->Diag(DRE->getSourceRange().getBegin(), 75 diag::err_param_default_argument_references_param, 76 Param->getName(), DefaultArg->getSourceRange()); 77 } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) { 78 // C++ [dcl.fct.default]p7 79 // Local variables shall not be used in default argument 80 // expressions. 81 if (VDecl->isBlockVarDecl()) 82 return S->Diag(DRE->getSourceRange().getBegin(), 83 diag::err_param_default_argument_references_local, 84 VDecl->getName(), DefaultArg->getSourceRange()); 85 } 86 87 // FIXME: when Clang has support for member functions, "this" 88 // will also need to be diagnosed. 89 90 return false; 91 } 92} 93 94/// ActOnParamDefaultArgument - Check whether the default argument 95/// provided for a function parameter is well-formed. If so, attach it 96/// to the parameter declaration. 97void 98Sema::ActOnParamDefaultArgument(DeclTy *param, SourceLocation EqualLoc, 99 ExprTy *defarg) { 100 ParmVarDecl *Param = (ParmVarDecl *)param; 101 llvm::OwningPtr<Expr> DefaultArg((Expr *)defarg); 102 QualType ParamType = Param->getType(); 103 104 // Default arguments are only permitted in C++ 105 if (!getLangOptions().CPlusPlus) { 106 Diag(EqualLoc, diag::err_param_default_argument, 107 DefaultArg->getSourceRange()); 108 return; 109 } 110 111 // C++ [dcl.fct.default]p5 112 // A default argument expression is implicitly converted (clause 113 // 4) to the parameter type. The default argument expression has 114 // the same semantic constraints as the initializer expression in 115 // a declaration of a variable of the parameter type, using the 116 // copy-initialization semantics (8.5). 117 // 118 // FIXME: CheckSingleAssignmentConstraints has the wrong semantics 119 // for C++ (since we want copy-initialization, not copy-assignment), 120 // but we don't have the right semantics implemented yet. Because of 121 // this, our error message is also very poor. 122 QualType DefaultArgType = DefaultArg->getType(); 123 Expr *DefaultArgPtr = DefaultArg.get(); 124 AssignConvertType ConvTy = CheckSingleAssignmentConstraints(ParamType, 125 DefaultArgPtr); 126 if (DefaultArgPtr != DefaultArg.get()) { 127 DefaultArg.take(); 128 DefaultArg.reset(DefaultArgPtr); 129 } 130 if (DiagnoseAssignmentResult(ConvTy, DefaultArg->getLocStart(), 131 ParamType, DefaultArgType, DefaultArg.get(), 132 "in default argument")) { 133 return; 134 } 135 136 // Check that the default argument is well-formed 137 CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this); 138 if (DefaultArgChecker.Visit(DefaultArg.get())) 139 return; 140 141 // Okay: add the default argument to the parameter 142 Param->setDefaultArg(DefaultArg.take()); 143} 144 145/// CheckExtraCXXDefaultArguments - Check for any extra default 146/// arguments in the declarator, which is not a function declaration 147/// or definition and therefore is not permitted to have default 148/// arguments. This routine should be invoked for every declarator 149/// that is not a function declaration or definition. 150void Sema::CheckExtraCXXDefaultArguments(Declarator &D) { 151 // C++ [dcl.fct.default]p3 152 // A default argument expression shall be specified only in the 153 // parameter-declaration-clause of a function declaration or in a 154 // template-parameter (14.1). It shall not be specified for a 155 // parameter pack. If it is specified in a 156 // parameter-declaration-clause, it shall not occur within a 157 // declarator or abstract-declarator of a parameter-declaration. 158 for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) { 159 DeclaratorChunk &chunk = D.getTypeObject(i); 160 if (chunk.Kind == DeclaratorChunk::Function) { 161 for (unsigned argIdx = 0; argIdx < chunk.Fun.NumArgs; ++argIdx) { 162 ParmVarDecl *Param = (ParmVarDecl *)chunk.Fun.ArgInfo[argIdx].Param; 163 if (Param->getDefaultArg()) { 164 Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc, 165 Param->getDefaultArg()->getSourceRange()); 166 Param->setDefaultArg(0); 167 } 168 } 169 } 170 } 171} 172 173// MergeCXXFunctionDecl - Merge two declarations of the same C++ 174// function, once we already know that they have the same 175// type. Subroutine of MergeFunctionDecl. 176FunctionDecl * 177Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) { 178 // C++ [dcl.fct.default]p4: 179 // 180 // For non-template functions, default arguments can be added in 181 // later declarations of a function in the same 182 // scope. Declarations in different scopes have completely 183 // distinct sets of default arguments. That is, declarations in 184 // inner scopes do not acquire default arguments from 185 // declarations in outer scopes, and vice versa. In a given 186 // function declaration, all parameters subsequent to a 187 // parameter with a default argument shall have default 188 // arguments supplied in this or previous declarations. A 189 // default argument shall not be redefined by a later 190 // declaration (not even to the same value). 191 for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) { 192 ParmVarDecl *OldParam = Old->getParamDecl(p); 193 ParmVarDecl *NewParam = New->getParamDecl(p); 194 195 if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) { 196 Diag(NewParam->getLocation(), 197 diag::err_param_default_argument_redefinition, 198 NewParam->getDefaultArg()->getSourceRange()); 199 Diag(OldParam->getLocation(), diag::err_previous_definition); 200 } else if (OldParam->getDefaultArg()) { 201 // Merge the old default argument into the new parameter 202 NewParam->setDefaultArg(OldParam->getDefaultArg()); 203 } 204 } 205 206 return New; 207} 208 209/// CheckCXXDefaultArguments - Verify that the default arguments for a 210/// function declaration are well-formed according to C++ 211/// [dcl.fct.default]. 212void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) { 213 unsigned NumParams = FD->getNumParams(); 214 unsigned p; 215 216 // Find first parameter with a default argument 217 for (p = 0; p < NumParams; ++p) { 218 ParmVarDecl *Param = FD->getParamDecl(p); 219 if (Param->getDefaultArg()) 220 break; 221 } 222 223 // C++ [dcl.fct.default]p4: 224 // In a given function declaration, all parameters 225 // subsequent to a parameter with a default argument shall 226 // have default arguments supplied in this or previous 227 // declarations. A default argument shall not be redefined 228 // by a later declaration (not even to the same value). 229 unsigned LastMissingDefaultArg = 0; 230 for(; p < NumParams; ++p) { 231 ParmVarDecl *Param = FD->getParamDecl(p); 232 if (!Param->getDefaultArg()) { 233 if (Param->getIdentifier()) 234 Diag(Param->getLocation(), 235 diag::err_param_default_argument_missing_name, 236 Param->getIdentifier()->getName()); 237 else 238 Diag(Param->getLocation(), 239 diag::err_param_default_argument_missing); 240 241 LastMissingDefaultArg = p; 242 } 243 } 244 245 if (LastMissingDefaultArg > 0) { 246 // Some default arguments were missing. Clear out all of the 247 // default arguments up to (and including) the last missing 248 // default argument, so that we leave the function parameters 249 // in a semantically valid state. 250 for (p = 0; p <= LastMissingDefaultArg; ++p) { 251 ParmVarDecl *Param = FD->getParamDecl(p); 252 if (Param->getDefaultArg()) { 253 delete Param->getDefaultArg(); 254 Param->setDefaultArg(0); 255 } 256 } 257 } 258} 259 260/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is 261/// one entry in the base class list of a class specifier, for 262/// example: 263/// class foo : public bar, virtual private baz { 264/// 'public bar' and 'virtual private baz' are each base-specifiers. 265Sema::BaseResult 266Sema::ActOnBaseSpecifier(DeclTy *classdecl, SourceRange SpecifierRange, 267 bool Virtual, AccessSpecifier Access, 268 TypeTy *basetype, SourceLocation BaseLoc) { 269 RecordDecl *Decl = (RecordDecl*)classdecl; 270 QualType BaseType = Context.getTypeDeclType((TypeDecl*)basetype); 271 272 // Base specifiers must be record types. 273 if (!BaseType->isRecordType()) { 274 Diag(BaseLoc, diag::err_base_must_be_class, SpecifierRange); 275 return true; 276 } 277 278 // C++ [class.union]p1: 279 // A union shall not be used as a base class. 280 if (BaseType->isUnionType()) { 281 Diag(BaseLoc, diag::err_union_as_base_class, SpecifierRange); 282 return true; 283 } 284 285 // C++ [class.union]p1: 286 // A union shall not have base classes. 287 if (Decl->isUnion()) { 288 Diag(Decl->getLocation(), diag::err_base_clause_on_union, 289 SpecifierRange); 290 return true; 291 } 292 293 // C++ [class.derived]p2: 294 // The class-name in a base-specifier shall not be an incompletely 295 // defined class. 296 if (BaseType->isIncompleteType()) { 297 Diag(BaseLoc, diag::err_incomplete_base_class, SpecifierRange); 298 return true; 299 } 300 301 // Create the base specifier. 302 return new CXXBaseSpecifier(SpecifierRange, Virtual, 303 BaseType->isClassType(), Access, BaseType); 304} 305 306/// ActOnBaseSpecifiers - Attach the given base specifiers to the 307/// class, after checking whether there are any duplicate base 308/// classes. 309void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases, 310 unsigned NumBases) { 311 if (NumBases == 0) 312 return; 313 314 // Used to keep track of which base types we have already seen, so 315 // that we can properly diagnose redundant direct base types. Note 316 // that the key is always the unqualified canonical type of the base 317 // class. 318 std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes; 319 320 // Copy non-redundant base specifiers into permanent storage. 321 CXXBaseSpecifier **BaseSpecs = (CXXBaseSpecifier **)Bases; 322 unsigned NumGoodBases = 0; 323 for (unsigned idx = 0; idx < NumBases; ++idx) { 324 QualType NewBaseType 325 = Context.getCanonicalType(BaseSpecs[idx]->getType()); 326 NewBaseType = NewBaseType.getUnqualifiedType(); 327 328 if (KnownBaseTypes[NewBaseType]) { 329 // C++ [class.mi]p3: 330 // A class shall not be specified as a direct base class of a 331 // derived class more than once. 332 Diag(BaseSpecs[idx]->getSourceRange().getBegin(), 333 diag::err_duplicate_base_class, 334 KnownBaseTypes[NewBaseType]->getType().getAsString(), 335 BaseSpecs[idx]->getSourceRange()); 336 337 // Delete the duplicate base class specifier; we're going to 338 // overwrite its pointer later. 339 delete BaseSpecs[idx]; 340 } else { 341 // Okay, add this new base class. 342 KnownBaseTypes[NewBaseType] = BaseSpecs[idx]; 343 BaseSpecs[NumGoodBases++] = BaseSpecs[idx]; 344 } 345 } 346 347 // Attach the remaining base class specifiers to the derived class. 348 CXXRecordDecl *Decl = (CXXRecordDecl*)ClassDecl; 349 Decl->setBases(BaseSpecs, NumGoodBases); 350 351 // Delete the remaining (good) base class specifiers, since their 352 // data has been copied into the CXXRecordDecl. 353 for (unsigned idx = 0; idx < NumGoodBases; ++idx) 354 delete BaseSpecs[idx]; 355} 356 357//===----------------------------------------------------------------------===// 358// C++ class member Handling 359//===----------------------------------------------------------------------===// 360 361/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union 362/// definition, when on C++. 363void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) { 364 Decl *Dcl = static_cast<Decl *>(D); 365 PushDeclContext(cast<CXXRecordDecl>(Dcl)); 366 FieldCollector->StartClass(); 367} 368 369/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member 370/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the 371/// bitfield width if there is one and 'InitExpr' specifies the initializer if 372/// any. 'LastInGroup' is non-null for cases where one declspec has multiple 373/// declarators on it. 374/// 375/// NOTE: Because of CXXFieldDecl's inability to be chained like ScopedDecls, if 376/// an instance field is declared, a new CXXFieldDecl is created but the method 377/// does *not* return it; it returns LastInGroup instead. The other C++ members 378/// (which are all ScopedDecls) are returned after appending them to 379/// LastInGroup. 380Sema::DeclTy * 381Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D, 382 ExprTy *BW, ExprTy *InitExpr, 383 DeclTy *LastInGroup) { 384 const DeclSpec &DS = D.getDeclSpec(); 385 IdentifierInfo *II = D.getIdentifier(); 386 Expr *BitWidth = static_cast<Expr*>(BW); 387 Expr *Init = static_cast<Expr*>(InitExpr); 388 SourceLocation Loc = D.getIdentifierLoc(); 389 390 // C++ 9.2p6: A member shall not be declared to have automatic storage 391 // duration (auto, register) or with the extern storage-class-specifier. 392 switch (DS.getStorageClassSpec()) { 393 case DeclSpec::SCS_unspecified: 394 case DeclSpec::SCS_typedef: 395 case DeclSpec::SCS_static: 396 // FALL THROUGH. 397 break; 398 default: 399 if (DS.getStorageClassSpecLoc().isValid()) 400 Diag(DS.getStorageClassSpecLoc(), 401 diag::err_storageclass_invalid_for_member); 402 else 403 Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member); 404 D.getMutableDeclSpec().ClearStorageClassSpecs(); 405 } 406 407 bool isFunc = D.isFunctionDeclarator(); 408 if (!isFunc && 409 D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef && 410 D.getNumTypeObjects() == 0) { 411 // Check also for this case: 412 // 413 // typedef int f(); 414 // f a; 415 // 416 Decl *TD = static_cast<Decl *>(DS.getTypeRep()); 417 isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType(); 418 } 419 420 bool isInstField = (DS.getStorageClassSpec() == DeclSpec::SCS_unspecified && 421 !isFunc); 422 423 Decl *Member; 424 bool InvalidDecl = false; 425 426 if (isInstField) 427 Member = static_cast<Decl*>(ActOnField(S, Loc, D, BitWidth)); 428 else 429 Member = static_cast<Decl*>(ActOnDeclarator(S, D, LastInGroup)); 430 431 if (!Member) return LastInGroup; 432 433 assert(II || isInstField && "No identifier for non-field ?"); 434 435 // set/getAccess is not part of Decl's interface to avoid bloating it with C++ 436 // specific methods. Use a wrapper class that can be used with all C++ class 437 // member decls. 438 CXXClassMemberWrapper(Member).setAccess(AS); 439 440 if (BitWidth) { 441 // C++ 9.6p2: Only when declaring an unnamed bit-field may the 442 // constant-expression be a value equal to zero. 443 // FIXME: Check this. 444 445 if (D.isFunctionDeclarator()) { 446 // FIXME: Emit diagnostic about only constructors taking base initializers 447 // or something similar, when constructor support is in place. 448 Diag(Loc, diag::err_not_bitfield_type, 449 II->getName(), BitWidth->getSourceRange()); 450 InvalidDecl = true; 451 452 } else if (isInstField) { 453 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 454 if (!cast<FieldDecl>(Member)->getType()->isIntegralType()) { 455 Diag(Loc, diag::err_not_integral_type_bitfield, 456 II->getName(), BitWidth->getSourceRange()); 457 InvalidDecl = true; 458 } 459 460 } else if (isa<FunctionDecl>(Member)) { 461 // A function typedef ("typedef int f(); f a;"). 462 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 463 Diag(Loc, diag::err_not_integral_type_bitfield, 464 II->getName(), BitWidth->getSourceRange()); 465 InvalidDecl = true; 466 467 } else if (isa<TypedefDecl>(Member)) { 468 // "cannot declare 'A' to be a bit-field type" 469 Diag(Loc, diag::err_not_bitfield_type, II->getName(), 470 BitWidth->getSourceRange()); 471 InvalidDecl = true; 472 473 } else { 474 assert(isa<CXXClassVarDecl>(Member) && 475 "Didn't we cover all member kinds?"); 476 // C++ 9.6p3: A bit-field shall not be a static member. 477 // "static member 'A' cannot be a bit-field" 478 Diag(Loc, diag::err_static_not_bitfield, II->getName(), 479 BitWidth->getSourceRange()); 480 InvalidDecl = true; 481 } 482 } 483 484 if (Init) { 485 // C++ 9.2p4: A member-declarator can contain a constant-initializer only 486 // if it declares a static member of const integral or const enumeration 487 // type. 488 if (CXXClassVarDecl *CVD = dyn_cast<CXXClassVarDecl>(Member)) { 489 // ...static member of... 490 CVD->setInit(Init); 491 // ...const integral or const enumeration type. 492 if (Context.getCanonicalType(CVD->getType()).isConstQualified() && 493 CVD->getType()->isIntegralType()) { 494 // constant-initializer 495 if (CheckForConstantInitializer(Init, CVD->getType())) 496 InvalidDecl = true; 497 498 } else { 499 // not const integral. 500 Diag(Loc, diag::err_member_initialization, 501 II->getName(), Init->getSourceRange()); 502 InvalidDecl = true; 503 } 504 505 } else { 506 // not static member. 507 Diag(Loc, diag::err_member_initialization, 508 II->getName(), Init->getSourceRange()); 509 InvalidDecl = true; 510 } 511 } 512 513 if (InvalidDecl) 514 Member->setInvalidDecl(); 515 516 if (isInstField) { 517 FieldCollector->Add(cast<CXXFieldDecl>(Member)); 518 return LastInGroup; 519 } 520 return Member; 521} 522 523void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc, 524 DeclTy *TagDecl, 525 SourceLocation LBrac, 526 SourceLocation RBrac) { 527 ActOnFields(S, RLoc, TagDecl, 528 (DeclTy**)FieldCollector->getCurFields(), 529 FieldCollector->getCurNumFields(), LBrac, RBrac, 0); 530} 531 532void Sema::ActOnFinishCXXClassDef(DeclTy *D) { 533 CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 534 FieldCollector->FinishClass(); 535 PopDeclContext(); 536 537 // Everything, including inline method definitions, have been parsed. 538 // Let the consumer know of the new TagDecl definition. 539 Consumer.HandleTagDeclDefinition(Rec); 540} 541 542//===----------------------------------------------------------------------===// 543// Namespace Handling 544//===----------------------------------------------------------------------===// 545 546/// ActOnStartNamespaceDef - This is called at the start of a namespace 547/// definition. 548Sema::DeclTy *Sema::ActOnStartNamespaceDef(Scope *NamespcScope, 549 SourceLocation IdentLoc, 550 IdentifierInfo *II, 551 SourceLocation LBrace) { 552 NamespaceDecl *Namespc = 553 NamespaceDecl::Create(Context, CurContext, IdentLoc, II); 554 Namespc->setLBracLoc(LBrace); 555 556 Scope *DeclRegionScope = NamespcScope->getParent(); 557 558 if (II) { 559 // C++ [namespace.def]p2: 560 // The identifier in an original-namespace-definition shall not have been 561 // previously defined in the declarative region in which the 562 // original-namespace-definition appears. The identifier in an 563 // original-namespace-definition is the name of the namespace. Subsequently 564 // in that declarative region, it is treated as an original-namespace-name. 565 566 Decl *PrevDecl = 567 LookupDecl(II, Decl::IDNS_Tag | Decl::IDNS_Ordinary, DeclRegionScope, 568 /*enableLazyBuiltinCreation=*/false); 569 570 if (PrevDecl && isDeclInScope(PrevDecl, CurContext, DeclRegionScope)) { 571 if (NamespaceDecl *OrigNS = dyn_cast<NamespaceDecl>(PrevDecl)) { 572 // This is an extended namespace definition. 573 // Attach this namespace decl to the chain of extended namespace 574 // definitions. 575 NamespaceDecl *NextNS = OrigNS; 576 while (NextNS->getNextNamespace()) 577 NextNS = NextNS->getNextNamespace(); 578 579 NextNS->setNextNamespace(Namespc); 580 Namespc->setOriginalNamespace(OrigNS); 581 582 // We won't add this decl to the current scope. We want the namespace 583 // name to return the original namespace decl during a name lookup. 584 } else { 585 // This is an invalid name redefinition. 586 Diag(Namespc->getLocation(), diag::err_redefinition_different_kind, 587 Namespc->getName()); 588 Diag(PrevDecl->getLocation(), diag::err_previous_definition); 589 Namespc->setInvalidDecl(); 590 // Continue on to push Namespc as current DeclContext and return it. 591 } 592 } else { 593 // This namespace name is declared for the first time. 594 PushOnScopeChains(Namespc, DeclRegionScope); 595 } 596 } 597 else { 598 // FIXME: Handle anonymous namespaces 599 } 600 601 // Although we could have an invalid decl (i.e. the namespace name is a 602 // redefinition), push it as current DeclContext and try to continue parsing. 603 PushDeclContext(Namespc->getOriginalNamespace()); 604 return Namespc; 605} 606 607/// ActOnFinishNamespaceDef - This callback is called after a namespace is 608/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef. 609void Sema::ActOnFinishNamespaceDef(DeclTy *D, SourceLocation RBrace) { 610 Decl *Dcl = static_cast<Decl *>(D); 611 NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl); 612 assert(Namespc && "Invalid parameter, expected NamespaceDecl"); 613 Namespc->setRBracLoc(RBrace); 614 PopDeclContext(); 615} 616 617 618/// AddCXXDirectInitializerToDecl - This action is called immediately after 619/// ActOnDeclarator, when a C++ direct initializer is present. 620/// e.g: "int x(1);" 621void Sema::AddCXXDirectInitializerToDecl(DeclTy *Dcl, SourceLocation LParenLoc, 622 ExprTy **ExprTys, unsigned NumExprs, 623 SourceLocation *CommaLocs, 624 SourceLocation RParenLoc) { 625 assert(NumExprs != 0 && ExprTys && "missing expressions"); 626 Decl *RealDecl = static_cast<Decl *>(Dcl); 627 628 // If there is no declaration, there was an error parsing it. Just ignore 629 // the initializer. 630 if (RealDecl == 0) { 631 for (unsigned i = 0; i != NumExprs; ++i) 632 delete static_cast<Expr *>(ExprTys[i]); 633 return; 634 } 635 636 VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl); 637 if (!VDecl) { 638 Diag(RealDecl->getLocation(), diag::err_illegal_initializer); 639 RealDecl->setInvalidDecl(); 640 return; 641 } 642 643 // We will treat direct-initialization as a copy-initialization: 644 // int x(1); -as-> int x = 1; 645 // ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c); 646 // 647 // Clients that want to distinguish between the two forms, can check for 648 // direct initializer using VarDecl::hasCXXDirectInitializer(). 649 // A major benefit is that clients that don't particularly care about which 650 // exactly form was it (like the CodeGen) can handle both cases without 651 // special case code. 652 653 // C++ 8.5p11: 654 // The form of initialization (using parentheses or '=') is generally 655 // insignificant, but does matter when the entity being initialized has a 656 // class type. 657 658 if (VDecl->getType()->isRecordType()) { 659 // FIXME: When constructors for class types are supported, determine how 660 // exactly semantic checking will be done for direct initializers. 661 unsigned DiagID = PP.getDiagnostics().getCustomDiagID(Diagnostic::Error, 662 "initialization for class types is not handled yet"); 663 Diag(VDecl->getLocation(), DiagID); 664 RealDecl->setInvalidDecl(); 665 return; 666 } 667 668 if (NumExprs > 1) { 669 Diag(CommaLocs[0], diag::err_builtin_direct_init_more_than_one_arg, 670 SourceRange(VDecl->getLocation(), RParenLoc)); 671 RealDecl->setInvalidDecl(); 672 return; 673 } 674 675 // Let clients know that initialization was done with a direct initializer. 676 VDecl->setCXXDirectInitializer(true); 677 678 assert(NumExprs == 1 && "Expected 1 expression"); 679 // Set the init expression, handles conversions. 680 AddInitializerToDecl(Dcl, ExprTys[0]); 681} 682 683/// CompareReferenceRelationship - Compare the two types T1 and T2 to 684/// determine whether they are reference-related, 685/// reference-compatible, reference-compatible with added 686/// qualification, or incompatible, for use in C++ initialization by 687/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 688/// type, and the first type (T1) is the pointee type of the reference 689/// type being initialized. 690Sema::ReferenceCompareResult 691Sema::CompareReferenceRelationship(QualType T1, QualType T2, 692 bool& DerivedToBase) { 693 assert(!T1->isReferenceType() && "T1 must be the pointee type of the reference type"); 694 assert(!T2->isReferenceType() && "T2 cannot be a reference type"); 695 696 T1 = Context.getCanonicalType(T1); 697 T2 = Context.getCanonicalType(T2); 698 QualType UnqualT1 = T1.getUnqualifiedType(); 699 QualType UnqualT2 = T2.getUnqualifiedType(); 700 701 // C++ [dcl.init.ref]p4: 702 // Given types “cv1 T1” and “cv2 T2,” “cv1 T1” is 703 // reference-related to “cv2 T2” if T1 is the same type as T2, or 704 // T1 is a base class of T2. 705 if (UnqualT1 == UnqualT2) 706 DerivedToBase = false; 707 else if (IsDerivedFrom(UnqualT2, UnqualT1)) 708 DerivedToBase = true; 709 else 710 return Ref_Incompatible; 711 712 // At this point, we know that T1 and T2 are reference-related (at 713 // least). 714 715 // C++ [dcl.init.ref]p4: 716 // "cv1 T1” is reference-compatible with “cv2 T2” if T1 is 717 // reference-related to T2 and cv1 is the same cv-qualification 718 // as, or greater cv-qualification than, cv2. For purposes of 719 // overload resolution, cases for which cv1 is greater 720 // cv-qualification than cv2 are identified as 721 // reference-compatible with added qualification (see 13.3.3.2). 722 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 723 return Ref_Compatible; 724 else if (T1.isMoreQualifiedThan(T2)) 725 return Ref_Compatible_With_Added_Qualification; 726 else 727 return Ref_Related; 728} 729 730/// CheckReferenceInit - Check the initialization of a reference 731/// variable with the given initializer (C++ [dcl.init.ref]). Init is 732/// the initializer (either a simple initializer or an initializer 733/// list), and DeclType is the type of the declaration. When Complain 734/// is true, this routine will produce diagnostics (and return true) 735/// when the declaration cannot be initialized with the given 736/// initializer. When ICS is non-null, this routine will compute the 737/// implicit conversion sequence according to C++ [over.ics.ref] and 738/// will not produce any diagnostics; when ICS is null, it will emit 739/// diagnostics when any errors are found. 740bool 741Sema::CheckReferenceInit(Expr *&Init, QualType &DeclType, 742 ImplicitConversionSequence *ICS) { 743 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 744 745 QualType T1 = DeclType->getAsReferenceType()->getPointeeType(); 746 QualType T2 = Init->getType(); 747 748 // Compute some basic properties of the types and the initializer. 749 bool DerivedToBase = false; 750 Expr::isLvalueResult InitLvalue = Init->isLvalue(Context); 751 ReferenceCompareResult RefRelationship 752 = CompareReferenceRelationship(T1, T2, DerivedToBase); 753 754 // Most paths end in a failed conversion. 755 if (ICS) 756 ICS->ConversionKind = ImplicitConversionSequence::BadConversion; 757 758 // C++ [dcl.init.ref]p5: 759 // A reference to type “cv1 T1” is initialized by an expression 760 // of type “cv2 T2” as follows: 761 762 // -- If the initializer expression 763 764 bool BindsDirectly = false; 765 // -- is an lvalue (but is not a bit-field), and “cv1 T1” is 766 // reference-compatible with “cv2 T2,” or 767 // 768 // Note that the bit-field check is skipped if we are just computing 769 // the implicit conversion sequence (C++ [over.best.ics]p2). 770 if (InitLvalue == Expr::LV_Valid && (ICS || !Init->isBitField()) && 771 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 772 BindsDirectly = true; 773 774 if (ICS) { 775 // C++ [over.ics.ref]p1: 776 // When a parameter of reference type binds directly (8.5.3) 777 // to an argument expression, the implicit conversion sequence 778 // is the identity conversion, unless the argument expression 779 // has a type that is a derived class of the parameter type, 780 // in which case the implicit conversion sequence is a 781 // derived-to-base Conversion (13.3.3.1). 782 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 783 ICS->Standard.First = ICK_Identity; 784 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 785 ICS->Standard.Third = ICK_Identity; 786 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 787 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 788 ICS->Standard.ReferenceBinding = true; 789 ICS->Standard.DirectBinding = true; 790 791 // Nothing more to do: the inaccessibility/ambiguity check for 792 // derived-to-base conversions is suppressed when we're 793 // computing the implicit conversion sequence (C++ 794 // [over.best.ics]p2). 795 return false; 796 } else { 797 // Perform the conversion. 798 // FIXME: Binding to a subobject of the lvalue is going to require 799 // more AST annotation than this. 800 ImpCastExprToType(Init, T1); 801 } 802 } 803 804 // -- has a class type (i.e., T2 is a class type) and can be 805 // implicitly converted to an lvalue of type “cv3 T3,” 806 // where “cv1 T1” is reference-compatible with “cv3 T3” 807 // 92) (this conversion is selected by enumerating the 808 // applicable conversion functions (13.3.1.6) and choosing 809 // the best one through overload resolution (13.3)), 810 // FIXME: Implement this second bullet, once we have conversion 811 // functions. Also remember C++ [over.ics.ref]p1, second part. 812 813 if (BindsDirectly) { 814 // C++ [dcl.init.ref]p4: 815 // [...] In all cases where the reference-related or 816 // reference-compatible relationship of two types is used to 817 // establish the validity of a reference binding, and T1 is a 818 // base class of T2, a program that necessitates such a binding 819 // is ill-formed if T1 is an inaccessible (clause 11) or 820 // ambiguous (10.2) base class of T2. 821 // 822 // Note that we only check this condition when we're allowed to 823 // complain about errors, because we should not be checking for 824 // ambiguity (or inaccessibility) unless the reference binding 825 // actually happens. 826 if (DerivedToBase) 827 return CheckDerivedToBaseConversion(T2, T1, 828 Init->getSourceRange().getBegin(), 829 Init->getSourceRange()); 830 else 831 return false; 832 } 833 834 // -- Otherwise, the reference shall be to a non-volatile const 835 // type (i.e., cv1 shall be const). 836 if (T1.getCVRQualifiers() != QualType::Const) { 837 if (!ICS) 838 Diag(Init->getSourceRange().getBegin(), 839 diag::err_not_reference_to_const_init, 840 T1.getAsString(), 841 InitLvalue != Expr::LV_Valid? "temporary" : "value", 842 T2.getAsString(), Init->getSourceRange()); 843 return true; 844 } 845 846 // -- If the initializer expression is an rvalue, with T2 a 847 // class type, and “cv1 T1” is reference-compatible with 848 // “cv2 T2,” the reference is bound in one of the 849 // following ways (the choice is implementation-defined): 850 // 851 // -- The reference is bound to the object represented by 852 // the rvalue (see 3.10) or to a sub-object within that 853 // object. 854 // 855 // -- A temporary of type “cv1 T2” [sic] is created, and 856 // a constructor is called to copy the entire rvalue 857 // object into the temporary. The reference is bound to 858 // the temporary or to a sub-object within the 859 // temporary. 860 // 861 // 862 // The constructor that would be used to make the copy 863 // shall be callable whether or not the copy is actually 864 // done. 865 // 866 // Note that C++0x [dcl.ref.init]p5 takes away this implementation 867 // freedom, so we will always take the first option and never build 868 // a temporary in this case. FIXME: We will, however, have to check 869 // for the presence of a copy constructor in C++98/03 mode. 870 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 871 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 872 if (ICS) { 873 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 874 ICS->Standard.First = ICK_Identity; 875 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 876 ICS->Standard.Third = ICK_Identity; 877 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 878 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 879 ICS->Standard.ReferenceBinding = true; 880 ICS->Standard.DirectBinding = false; 881 } else { 882 // FIXME: Binding to a subobject of the rvalue is going to require 883 // more AST annotation than this. 884 ImpCastExprToType(Init, T1); 885 } 886 return false; 887 } 888 889 // -- Otherwise, a temporary of type “cv1 T1” is created and 890 // initialized from the initializer expression using the 891 // rules for a non-reference copy initialization (8.5). The 892 // reference is then bound to the temporary. If T1 is 893 // reference-related to T2, cv1 must be the same 894 // cv-qualification as, or greater cv-qualification than, 895 // cv2; otherwise, the program is ill-formed. 896 if (RefRelationship == Ref_Related) { 897 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 898 // we would be reference-compatible or reference-compatible with 899 // added qualification. But that wasn't the case, so the reference 900 // initialization fails. 901 if (!ICS) 902 Diag(Init->getSourceRange().getBegin(), 903 diag::err_reference_init_drops_quals, 904 T1.getAsString(), 905 InitLvalue != Expr::LV_Valid? "temporary" : "value", 906 T2.getAsString(), Init->getSourceRange()); 907 return true; 908 } 909 910 // Actually try to convert the initializer to T1. 911 if (ICS) { 912 /// C++ [over.ics.ref]p2: 913 /// 914 /// When a parameter of reference type is not bound directly to 915 /// an argument expression, the conversion sequence is the one 916 /// required to convert the argument expression to the 917 /// underlying type of the reference according to 918 /// 13.3.3.1. Conceptually, this conversion sequence corresponds 919 /// to copy-initializing a temporary of the underlying type with 920 /// the argument expression. Any difference in top-level 921 /// cv-qualification is subsumed by the initialization itself 922 /// and does not constitute a conversion. 923 *ICS = TryImplicitConversion(Init, T1); 924 return ICS->ConversionKind == ImplicitConversionSequence::BadConversion; 925 } else { 926 return PerformImplicitConversion(Init, T1); 927 } 928} 929