SemaDeclCXX.cpp revision 7ad8390f7992ab7f19b1460c5f0b9d96f165c4e9
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 "SemaInherit.h" 16#include "clang/AST/ASTConsumer.h" 17#include "clang/AST/ASTContext.h" 18#include "clang/AST/TypeOrdering.h" 19#include "clang/AST/StmtVisitor.h" 20#include "clang/Lex/Preprocessor.h" 21#include "clang/Basic/Diagnostic.h" 22#include "clang/Parse/DeclSpec.h" 23#include "llvm/Support/Compiler.h" 24#include <algorithm> // for std::equal 25#include <map> 26 27using namespace clang; 28 29//===----------------------------------------------------------------------===// 30// CheckDefaultArgumentVisitor 31//===----------------------------------------------------------------------===// 32 33namespace { 34 /// CheckDefaultArgumentVisitor - C++ [dcl.fct.default] Traverses 35 /// the default argument of a parameter to determine whether it 36 /// contains any ill-formed subexpressions. For example, this will 37 /// diagnose the use of local variables or parameters within the 38 /// default argument expression. 39 class VISIBILITY_HIDDEN CheckDefaultArgumentVisitor 40 : public StmtVisitor<CheckDefaultArgumentVisitor, bool> { 41 Expr *DefaultArg; 42 Sema *S; 43 44 public: 45 CheckDefaultArgumentVisitor(Expr *defarg, Sema *s) 46 : DefaultArg(defarg), S(s) {} 47 48 bool VisitExpr(Expr *Node); 49 bool VisitDeclRefExpr(DeclRefExpr *DRE); 50 bool VisitCXXThisExpr(CXXThisExpr *ThisE); 51 }; 52 53 /// VisitExpr - Visit all of the children of this expression. 54 bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) { 55 bool IsInvalid = false; 56 for (Stmt::child_iterator I = Node->child_begin(), 57 E = Node->child_end(); I != E; ++I) 58 IsInvalid |= Visit(*I); 59 return IsInvalid; 60 } 61 62 /// VisitDeclRefExpr - Visit a reference to a declaration, to 63 /// determine whether this declaration can be used in the default 64 /// argument expression. 65 bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) { 66 NamedDecl *Decl = DRE->getDecl(); 67 if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) { 68 // C++ [dcl.fct.default]p9 69 // Default arguments are evaluated each time the function is 70 // called. The order of evaluation of function arguments is 71 // unspecified. Consequently, parameters of a function shall not 72 // be used in default argument expressions, even if they are not 73 // evaluated. Parameters of a function declared before a default 74 // argument expression are in scope and can hide namespace and 75 // class member names. 76 return S->Diag(DRE->getSourceRange().getBegin(), 77 diag::err_param_default_argument_references_param, 78 Param->getName(), DefaultArg->getSourceRange()); 79 } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) { 80 // C++ [dcl.fct.default]p7 81 // Local variables shall not be used in default argument 82 // expressions. 83 if (VDecl->isBlockVarDecl()) 84 return S->Diag(DRE->getSourceRange().getBegin(), 85 diag::err_param_default_argument_references_local, 86 VDecl->getName(), DefaultArg->getSourceRange()); 87 } 88 89 return false; 90 } 91 92 /// VisitCXXThisExpr - Visit a C++ "this" expression. 93 bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) { 94 // C++ [dcl.fct.default]p8: 95 // The keyword this shall not be used in a default argument of a 96 // member function. 97 return S->Diag(ThisE->getSourceRange().getBegin(), 98 diag::err_param_default_argument_references_this, 99 ThisE->getSourceRange()); 100 } 101} 102 103/// ActOnParamDefaultArgument - Check whether the default argument 104/// provided for a function parameter is well-formed. If so, attach it 105/// to the parameter declaration. 106void 107Sema::ActOnParamDefaultArgument(DeclTy *param, SourceLocation EqualLoc, 108 ExprTy *defarg) { 109 ParmVarDecl *Param = (ParmVarDecl *)param; 110 llvm::OwningPtr<Expr> DefaultArg((Expr *)defarg); 111 QualType ParamType = Param->getType(); 112 113 // Default arguments are only permitted in C++ 114 if (!getLangOptions().CPlusPlus) { 115 Diag(EqualLoc, diag::err_param_default_argument, 116 DefaultArg->getSourceRange()); 117 return; 118 } 119 120 // C++ [dcl.fct.default]p5 121 // A default argument expression is implicitly converted (clause 122 // 4) to the parameter type. The default argument expression has 123 // the same semantic constraints as the initializer expression in 124 // a declaration of a variable of the parameter type, using the 125 // copy-initialization semantics (8.5). 126 Expr *DefaultArgPtr = DefaultArg.get(); 127 bool DefaultInitFailed = PerformCopyInitialization(DefaultArgPtr, ParamType, 128 "in default argument"); 129 if (DefaultArgPtr != DefaultArg.get()) { 130 DefaultArg.take(); 131 DefaultArg.reset(DefaultArgPtr); 132 } 133 if (DefaultInitFailed) { 134 return; 135 } 136 137 // Check that the default argument is well-formed 138 CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this); 139 if (DefaultArgChecker.Visit(DefaultArg.get())) 140 return; 141 142 // Okay: add the default argument to the parameter 143 Param->setDefaultArg(DefaultArg.take()); 144} 145 146/// CheckExtraCXXDefaultArguments - Check for any extra default 147/// arguments in the declarator, which is not a function declaration 148/// or definition and therefore is not permitted to have default 149/// arguments. This routine should be invoked for every declarator 150/// that is not a function declaration or definition. 151void Sema::CheckExtraCXXDefaultArguments(Declarator &D) { 152 // C++ [dcl.fct.default]p3 153 // A default argument expression shall be specified only in the 154 // parameter-declaration-clause of a function declaration or in a 155 // template-parameter (14.1). It shall not be specified for a 156 // parameter pack. If it is specified in a 157 // parameter-declaration-clause, it shall not occur within a 158 // declarator or abstract-declarator of a parameter-declaration. 159 for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) { 160 DeclaratorChunk &chunk = D.getTypeObject(i); 161 if (chunk.Kind == DeclaratorChunk::Function) { 162 for (unsigned argIdx = 0; argIdx < chunk.Fun.NumArgs; ++argIdx) { 163 ParmVarDecl *Param = (ParmVarDecl *)chunk.Fun.ArgInfo[argIdx].Param; 164 if (Param->getDefaultArg()) { 165 Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc, 166 Param->getDefaultArg()->getSourceRange()); 167 Param->setDefaultArg(0); 168 } 169 } 170 } 171 } 172} 173 174// MergeCXXFunctionDecl - Merge two declarations of the same C++ 175// function, once we already know that they have the same 176// type. Subroutine of MergeFunctionDecl. 177FunctionDecl * 178Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) { 179 // C++ [dcl.fct.default]p4: 180 // 181 // For non-template functions, default arguments can be added in 182 // later declarations of a function in the same 183 // scope. Declarations in different scopes have completely 184 // distinct sets of default arguments. That is, declarations in 185 // inner scopes do not acquire default arguments from 186 // declarations in outer scopes, and vice versa. In a given 187 // function declaration, all parameters subsequent to a 188 // parameter with a default argument shall have default 189 // arguments supplied in this or previous declarations. A 190 // default argument shall not be redefined by a later 191 // declaration (not even to the same value). 192 for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) { 193 ParmVarDecl *OldParam = Old->getParamDecl(p); 194 ParmVarDecl *NewParam = New->getParamDecl(p); 195 196 if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) { 197 Diag(NewParam->getLocation(), 198 diag::err_param_default_argument_redefinition, 199 NewParam->getDefaultArg()->getSourceRange()); 200 Diag(OldParam->getLocation(), diag::err_previous_definition); 201 } else if (OldParam->getDefaultArg()) { 202 // Merge the old default argument into the new parameter 203 NewParam->setDefaultArg(OldParam->getDefaultArg()); 204 } 205 } 206 207 return New; 208} 209 210/// CheckCXXDefaultArguments - Verify that the default arguments for a 211/// function declaration are well-formed according to C++ 212/// [dcl.fct.default]. 213void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) { 214 unsigned NumParams = FD->getNumParams(); 215 unsigned p; 216 217 // Find first parameter with a default argument 218 for (p = 0; p < NumParams; ++p) { 219 ParmVarDecl *Param = FD->getParamDecl(p); 220 if (Param->getDefaultArg()) 221 break; 222 } 223 224 // C++ [dcl.fct.default]p4: 225 // In a given function declaration, all parameters 226 // subsequent to a parameter with a default argument shall 227 // have default arguments supplied in this or previous 228 // declarations. A default argument shall not be redefined 229 // by a later declaration (not even to the same value). 230 unsigned LastMissingDefaultArg = 0; 231 for(; p < NumParams; ++p) { 232 ParmVarDecl *Param = FD->getParamDecl(p); 233 if (!Param->getDefaultArg()) { 234 if (Param->getIdentifier()) 235 Diag(Param->getLocation(), 236 diag::err_param_default_argument_missing_name, 237 Param->getIdentifier()->getName()); 238 else 239 Diag(Param->getLocation(), 240 diag::err_param_default_argument_missing); 241 242 LastMissingDefaultArg = p; 243 } 244 } 245 246 if (LastMissingDefaultArg > 0) { 247 // Some default arguments were missing. Clear out all of the 248 // default arguments up to (and including) the last missing 249 // default argument, so that we leave the function parameters 250 // in a semantically valid state. 251 for (p = 0; p <= LastMissingDefaultArg; ++p) { 252 ParmVarDecl *Param = FD->getParamDecl(p); 253 if (Param->getDefaultArg()) { 254 delete Param->getDefaultArg(); 255 Param->setDefaultArg(0); 256 } 257 } 258 } 259} 260 261/// isCurrentClassName - Determine whether the identifier II is the 262/// name of the class type currently being defined. In the case of 263/// nested classes, this will only return true if II is the name of 264/// the innermost class. 265bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *) { 266 if (CXXRecordDecl *CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext)) 267 return &II == CurDecl->getIdentifier(); 268 else 269 return false; 270} 271 272/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is 273/// one entry in the base class list of a class specifier, for 274/// example: 275/// class foo : public bar, virtual private baz { 276/// 'public bar' and 'virtual private baz' are each base-specifiers. 277Sema::BaseResult 278Sema::ActOnBaseSpecifier(DeclTy *classdecl, SourceRange SpecifierRange, 279 bool Virtual, AccessSpecifier Access, 280 TypeTy *basetype, SourceLocation BaseLoc) { 281 RecordDecl *Decl = (RecordDecl*)classdecl; 282 QualType BaseType = Context.getTypeDeclType((TypeDecl*)basetype); 283 284 // Base specifiers must be record types. 285 if (!BaseType->isRecordType()) { 286 Diag(BaseLoc, diag::err_base_must_be_class, SpecifierRange); 287 return true; 288 } 289 290 // C++ [class.union]p1: 291 // A union shall not be used as a base class. 292 if (BaseType->isUnionType()) { 293 Diag(BaseLoc, diag::err_union_as_base_class, SpecifierRange); 294 return true; 295 } 296 297 // C++ [class.union]p1: 298 // A union shall not have base classes. 299 if (Decl->isUnion()) { 300 Diag(Decl->getLocation(), diag::err_base_clause_on_union, 301 SpecifierRange); 302 return true; 303 } 304 305 // C++ [class.derived]p2: 306 // The class-name in a base-specifier shall not be an incompletely 307 // defined class. 308 if (BaseType->isIncompleteType()) { 309 Diag(BaseLoc, diag::err_incomplete_base_class, SpecifierRange); 310 return true; 311 } 312 313 // Create the base specifier. 314 return new CXXBaseSpecifier(SpecifierRange, Virtual, 315 BaseType->isClassType(), Access, BaseType); 316} 317 318/// ActOnBaseSpecifiers - Attach the given base specifiers to the 319/// class, after checking whether there are any duplicate base 320/// classes. 321void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases, 322 unsigned NumBases) { 323 if (NumBases == 0) 324 return; 325 326 // Used to keep track of which base types we have already seen, so 327 // that we can properly diagnose redundant direct base types. Note 328 // that the key is always the unqualified canonical type of the base 329 // class. 330 std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes; 331 332 // Copy non-redundant base specifiers into permanent storage. 333 CXXBaseSpecifier **BaseSpecs = (CXXBaseSpecifier **)Bases; 334 unsigned NumGoodBases = 0; 335 for (unsigned idx = 0; idx < NumBases; ++idx) { 336 QualType NewBaseType 337 = Context.getCanonicalType(BaseSpecs[idx]->getType()); 338 NewBaseType = NewBaseType.getUnqualifiedType(); 339 340 if (KnownBaseTypes[NewBaseType]) { 341 // C++ [class.mi]p3: 342 // A class shall not be specified as a direct base class of a 343 // derived class more than once. 344 Diag(BaseSpecs[idx]->getSourceRange().getBegin(), 345 diag::err_duplicate_base_class, 346 KnownBaseTypes[NewBaseType]->getType().getAsString(), 347 BaseSpecs[idx]->getSourceRange()); 348 349 // Delete the duplicate base class specifier; we're going to 350 // overwrite its pointer later. 351 delete BaseSpecs[idx]; 352 } else { 353 // Okay, add this new base class. 354 KnownBaseTypes[NewBaseType] = BaseSpecs[idx]; 355 BaseSpecs[NumGoodBases++] = BaseSpecs[idx]; 356 } 357 } 358 359 // Attach the remaining base class specifiers to the derived class. 360 CXXRecordDecl *Decl = (CXXRecordDecl*)ClassDecl; 361 Decl->setBases(BaseSpecs, NumGoodBases); 362 363 // Delete the remaining (good) base class specifiers, since their 364 // data has been copied into the CXXRecordDecl. 365 for (unsigned idx = 0; idx < NumGoodBases; ++idx) 366 delete BaseSpecs[idx]; 367} 368 369//===----------------------------------------------------------------------===// 370// C++ class member Handling 371//===----------------------------------------------------------------------===// 372 373/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union 374/// definition, when on C++. 375void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) { 376 CXXRecordDecl *Dcl = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 377 PushDeclContext(Dcl); 378 FieldCollector->StartClass(); 379 380 if (Dcl->getIdentifier()) { 381 // C++ [class]p2: 382 // [...] The class-name is also inserted into the scope of the 383 // class itself; this is known as the injected-class-name. For 384 // purposes of access checking, the injected-class-name is treated 385 // as if it were a public member name. 386 TypedefDecl *InjectedClassName 387 = TypedefDecl::Create(Context, Dcl, LBrace, Dcl->getIdentifier(), 388 Context.getTypeDeclType(Dcl), /*PrevDecl=*/0); 389 PushOnScopeChains(InjectedClassName, S); 390 } 391} 392 393/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member 394/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the 395/// bitfield width if there is one and 'InitExpr' specifies the initializer if 396/// any. 'LastInGroup' is non-null for cases where one declspec has multiple 397/// declarators on it. 398/// 399/// NOTE: Because of CXXFieldDecl's inability to be chained like ScopedDecls, if 400/// an instance field is declared, a new CXXFieldDecl is created but the method 401/// does *not* return it; it returns LastInGroup instead. The other C++ members 402/// (which are all ScopedDecls) are returned after appending them to 403/// LastInGroup. 404Sema::DeclTy * 405Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D, 406 ExprTy *BW, ExprTy *InitExpr, 407 DeclTy *LastInGroup) { 408 const DeclSpec &DS = D.getDeclSpec(); 409 IdentifierInfo *II = D.getIdentifier(); 410 Expr *BitWidth = static_cast<Expr*>(BW); 411 Expr *Init = static_cast<Expr*>(InitExpr); 412 SourceLocation Loc = D.getIdentifierLoc(); 413 414 // C++ 9.2p6: A member shall not be declared to have automatic storage 415 // duration (auto, register) or with the extern storage-class-specifier. 416 switch (DS.getStorageClassSpec()) { 417 case DeclSpec::SCS_unspecified: 418 case DeclSpec::SCS_typedef: 419 case DeclSpec::SCS_static: 420 // FALL THROUGH. 421 break; 422 default: 423 if (DS.getStorageClassSpecLoc().isValid()) 424 Diag(DS.getStorageClassSpecLoc(), 425 diag::err_storageclass_invalid_for_member); 426 else 427 Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member); 428 D.getMutableDeclSpec().ClearStorageClassSpecs(); 429 } 430 431 bool isFunc = D.isFunctionDeclarator(); 432 if (!isFunc && 433 D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef && 434 D.getNumTypeObjects() == 0) { 435 // Check also for this case: 436 // 437 // typedef int f(); 438 // f a; 439 // 440 Decl *TD = static_cast<Decl *>(DS.getTypeRep()); 441 isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType(); 442 } 443 444 bool isInstField = (DS.getStorageClassSpec() == DeclSpec::SCS_unspecified && 445 !isFunc); 446 447 Decl *Member; 448 bool InvalidDecl = false; 449 450 if (isInstField) 451 Member = static_cast<Decl*>(ActOnField(S, Loc, D, BitWidth)); 452 else 453 Member = static_cast<Decl*>(ActOnDeclarator(S, D, LastInGroup)); 454 455 if (!Member) return LastInGroup; 456 457 assert((II || isInstField) && "No identifier for non-field ?"); 458 459 // set/getAccess is not part of Decl's interface to avoid bloating it with C++ 460 // specific methods. Use a wrapper class that can be used with all C++ class 461 // member decls. 462 CXXClassMemberWrapper(Member).setAccess(AS); 463 464 if (BitWidth) { 465 // C++ 9.6p2: Only when declaring an unnamed bit-field may the 466 // constant-expression be a value equal to zero. 467 // FIXME: Check this. 468 469 if (D.isFunctionDeclarator()) { 470 // FIXME: Emit diagnostic about only constructors taking base initializers 471 // or something similar, when constructor support is in place. 472 Diag(Loc, diag::err_not_bitfield_type, 473 II->getName(), BitWidth->getSourceRange()); 474 InvalidDecl = true; 475 476 } else if (isInstField) { 477 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 478 if (!cast<FieldDecl>(Member)->getType()->isIntegralType()) { 479 Diag(Loc, diag::err_not_integral_type_bitfield, 480 II->getName(), BitWidth->getSourceRange()); 481 InvalidDecl = true; 482 } 483 484 } else if (isa<FunctionDecl>(Member)) { 485 // A function typedef ("typedef int f(); f a;"). 486 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 487 Diag(Loc, diag::err_not_integral_type_bitfield, 488 II->getName(), BitWidth->getSourceRange()); 489 InvalidDecl = true; 490 491 } else if (isa<TypedefDecl>(Member)) { 492 // "cannot declare 'A' to be a bit-field type" 493 Diag(Loc, diag::err_not_bitfield_type, II->getName(), 494 BitWidth->getSourceRange()); 495 InvalidDecl = true; 496 497 } else { 498 assert(isa<CXXClassVarDecl>(Member) && 499 "Didn't we cover all member kinds?"); 500 // C++ 9.6p3: A bit-field shall not be a static member. 501 // "static member 'A' cannot be a bit-field" 502 Diag(Loc, diag::err_static_not_bitfield, II->getName(), 503 BitWidth->getSourceRange()); 504 InvalidDecl = true; 505 } 506 } 507 508 if (Init) { 509 // C++ 9.2p4: A member-declarator can contain a constant-initializer only 510 // if it declares a static member of const integral or const enumeration 511 // type. 512 if (CXXClassVarDecl *CVD = dyn_cast<CXXClassVarDecl>(Member)) { 513 // ...static member of... 514 CVD->setInit(Init); 515 // ...const integral or const enumeration type. 516 if (Context.getCanonicalType(CVD->getType()).isConstQualified() && 517 CVD->getType()->isIntegralType()) { 518 // constant-initializer 519 if (CheckForConstantInitializer(Init, CVD->getType())) 520 InvalidDecl = true; 521 522 } else { 523 // not const integral. 524 Diag(Loc, diag::err_member_initialization, 525 II->getName(), Init->getSourceRange()); 526 InvalidDecl = true; 527 } 528 529 } else { 530 // not static member. 531 Diag(Loc, diag::err_member_initialization, 532 II->getName(), Init->getSourceRange()); 533 InvalidDecl = true; 534 } 535 } 536 537 if (InvalidDecl) 538 Member->setInvalidDecl(); 539 540 if (isInstField) { 541 FieldCollector->Add(cast<CXXFieldDecl>(Member)); 542 return LastInGroup; 543 } 544 return Member; 545} 546 547/// ActOnMemInitializer - Handle a C++ member initializer. 548Sema::MemInitResult 549Sema::ActOnMemInitializer(DeclTy *ConstructorD, 550 Scope *S, 551 IdentifierInfo *MemberOrBase, 552 SourceLocation IdLoc, 553 SourceLocation LParenLoc, 554 ExprTy **Args, unsigned NumArgs, 555 SourceLocation *CommaLocs, 556 SourceLocation RParenLoc) { 557 CXXConstructorDecl *Constructor 558 = dyn_cast<CXXConstructorDecl>((Decl*)ConstructorD); 559 if (!Constructor) { 560 // The user wrote a constructor initializer on a function that is 561 // not a C++ constructor. Ignore the error for now, because we may 562 // have more member initializers coming; we'll diagnose it just 563 // once in ActOnMemInitializers. 564 return true; 565 } 566 567 CXXRecordDecl *ClassDecl = Constructor->getParent(); 568 569 // C++ [class.base.init]p2: 570 // Names in a mem-initializer-id are looked up in the scope of the 571 // constructor’s class and, if not found in that scope, are looked 572 // up in the scope containing the constructor’s 573 // definition. [Note: if the constructor’s class contains a member 574 // with the same name as a direct or virtual base class of the 575 // class, a mem-initializer-id naming the member or base class and 576 // composed of a single identifier refers to the class member. A 577 // mem-initializer-id for the hidden base class may be specified 578 // using a qualified name. ] 579 // Look for a member, first. 580 CXXFieldDecl *Member = ClassDecl->getMember(MemberOrBase); 581 582 // FIXME: Handle members of an anonymous union. 583 584 if (Member) { 585 // FIXME: Perform direct initialization of the member. 586 return new CXXBaseOrMemberInitializer(Member, (Expr **)Args, NumArgs); 587 } 588 589 // It didn't name a member, so see if it names a class. 590 TypeTy *BaseTy = isTypeName(*MemberOrBase, S); 591 if (!BaseTy) 592 return Diag(IdLoc, diag::err_mem_init_not_member_or_class, 593 MemberOrBase->getName(), SourceRange(IdLoc, RParenLoc)); 594 595 QualType BaseType = Context.getTypeDeclType((TypeDecl *)BaseTy); 596 if (!BaseType->isRecordType()) 597 return Diag(IdLoc, diag::err_base_init_does_not_name_class, 598 BaseType.getAsString(), SourceRange(IdLoc, RParenLoc)); 599 600 // C++ [class.base.init]p2: 601 // [...] Unless the mem-initializer-id names a nonstatic data 602 // member of the constructor’s class or a direct or virtual base 603 // of that class, the mem-initializer is ill-formed. A 604 // mem-initializer-list can initialize a base class using any 605 // name that denotes that base class type. 606 607 // First, check for a direct base class. 608 const CXXBaseSpecifier *DirectBaseSpec = 0; 609 for (CXXRecordDecl::base_class_const_iterator Base = ClassDecl->bases_begin(); 610 Base != ClassDecl->bases_end(); ++Base) { 611 if (Context.getCanonicalType(BaseType).getUnqualifiedType() == 612 Context.getCanonicalType(Base->getType()).getUnqualifiedType()) { 613 // We found a direct base of this type. That's what we're 614 // initializing. 615 DirectBaseSpec = &*Base; 616 break; 617 } 618 } 619 620 // Check for a virtual base class. 621 // FIXME: We might be able to short-circuit this if we know in 622 // advance that there are no virtual bases. 623 const CXXBaseSpecifier *VirtualBaseSpec = 0; 624 if (!DirectBaseSpec || !DirectBaseSpec->isVirtual()) { 625 // We haven't found a base yet; search the class hierarchy for a 626 // virtual base class. 627 BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 628 /*DetectVirtual=*/false); 629 if (IsDerivedFrom(Context.getTypeDeclType(ClassDecl), BaseType, Paths)) { 630 for (BasePaths::paths_iterator Path = Paths.begin(); 631 Path != Paths.end(); ++Path) { 632 if (Path->back().Base->isVirtual()) { 633 VirtualBaseSpec = Path->back().Base; 634 break; 635 } 636 } 637 } 638 } 639 640 // C++ [base.class.init]p2: 641 // If a mem-initializer-id is ambiguous because it designates both 642 // a direct non-virtual base class and an inherited virtual base 643 // class, the mem-initializer is ill-formed. 644 if (DirectBaseSpec && VirtualBaseSpec) 645 return Diag(IdLoc, diag::err_base_init_direct_and_virtual, 646 MemberOrBase->getName(), SourceRange(IdLoc, RParenLoc)); 647 648 return new CXXBaseOrMemberInitializer(BaseType, (Expr **)Args, NumArgs); 649} 650 651 652void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc, 653 DeclTy *TagDecl, 654 SourceLocation LBrac, 655 SourceLocation RBrac) { 656 ActOnFields(S, RLoc, TagDecl, 657 (DeclTy**)FieldCollector->getCurFields(), 658 FieldCollector->getCurNumFields(), LBrac, RBrac, 0); 659} 660 661/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared 662/// special functions, such as the default constructor, copy 663/// constructor, or destructor, to the given C++ class (C++ 664/// [special]p1). This routine can only be executed just before the 665/// definition of the class is complete. 666void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) { 667 if (!ClassDecl->hasUserDeclaredConstructor()) { 668 // C++ [class.ctor]p5: 669 // A default constructor for a class X is a constructor of class X 670 // that can be called without an argument. If there is no 671 // user-declared constructor for class X, a default constructor is 672 // implicitly declared. An implicitly-declared default constructor 673 // is an inline public member of its class. 674 CXXConstructorDecl *DefaultCon = 675 CXXConstructorDecl::Create(Context, ClassDecl, 676 ClassDecl->getLocation(), 677 ClassDecl->getIdentifier(), 678 Context.getFunctionType(Context.VoidTy, 679 0, 0, false, 0), 680 /*isExplicit=*/false, 681 /*isInline=*/true, 682 /*isImplicitlyDeclared=*/true); 683 DefaultCon->setAccess(AS_public); 684 ClassDecl->addConstructor(Context, DefaultCon); 685 } 686 687 if (!ClassDecl->hasUserDeclaredCopyConstructor()) { 688 // C++ [class.copy]p4: 689 // If the class definition does not explicitly declare a copy 690 // constructor, one is declared implicitly. 691 692 // C++ [class.copy]p5: 693 // The implicitly-declared copy constructor for a class X will 694 // have the form 695 // 696 // X::X(const X&) 697 // 698 // if 699 bool HasConstCopyConstructor = true; 700 701 // -- each direct or virtual base class B of X has a copy 702 // constructor whose first parameter is of type const B& or 703 // const volatile B&, and 704 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 705 HasConstCopyConstructor && Base != ClassDecl->bases_end(); ++Base) { 706 const CXXRecordDecl *BaseClassDecl 707 = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl()); 708 HasConstCopyConstructor 709 = BaseClassDecl->hasConstCopyConstructor(Context); 710 } 711 712 // -- for all the nonstatic data members of X that are of a 713 // class type M (or array thereof), each such class type 714 // has a copy constructor whose first parameter is of type 715 // const M& or const volatile M&. 716 for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(); 717 HasConstCopyConstructor && Field != ClassDecl->field_end(); ++Field) { 718 QualType FieldType = (*Field)->getType(); 719 if (const ArrayType *Array = Context.getAsArrayType(FieldType)) 720 FieldType = Array->getElementType(); 721 if (const RecordType *FieldClassType = FieldType->getAsRecordType()) { 722 const CXXRecordDecl *FieldClassDecl 723 = cast<CXXRecordDecl>(FieldClassType->getDecl()); 724 HasConstCopyConstructor 725 = FieldClassDecl->hasConstCopyConstructor(Context); 726 } 727 } 728 729 // Otherwise, the implicitly declared copy constructor will have 730 // the form 731 // 732 // X::X(X&) 733 QualType ArgType = Context.getTypeDeclType(ClassDecl); 734 if (HasConstCopyConstructor) 735 ArgType = ArgType.withConst(); 736 ArgType = Context.getReferenceType(ArgType); 737 738 // An implicitly-declared copy constructor is an inline public 739 // member of its class. 740 CXXConstructorDecl *CopyConstructor 741 = CXXConstructorDecl::Create(Context, ClassDecl, 742 ClassDecl->getLocation(), 743 ClassDecl->getIdentifier(), 744 Context.getFunctionType(Context.VoidTy, 745 &ArgType, 1, 746 false, 0), 747 /*isExplicit=*/false, 748 /*isInline=*/true, 749 /*isImplicitlyDeclared=*/true); 750 CopyConstructor->setAccess(AS_public); 751 752 // Add the parameter to the constructor. 753 ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor, 754 ClassDecl->getLocation(), 755 /*IdentifierInfo=*/0, 756 ArgType, VarDecl::None, 0, 0); 757 CopyConstructor->setParams(&FromParam, 1); 758 759 ClassDecl->addConstructor(Context, CopyConstructor); 760 } 761 762 // FIXME: Implicit destructor 763 // FIXME: Implicit copy assignment operator 764} 765 766void Sema::ActOnFinishCXXClassDef(DeclTy *D) { 767 CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 768 FieldCollector->FinishClass(); 769 AddImplicitlyDeclaredMembersToClass(Rec); 770 PopDeclContext(); 771 772 // Everything, including inline method definitions, have been parsed. 773 // Let the consumer know of the new TagDecl definition. 774 Consumer.HandleTagDeclDefinition(Rec); 775} 776 777/// ActOnConstructorDeclarator - Called by ActOnDeclarator to complete 778/// the declaration of the given C++ constructor ConDecl that was 779/// built from declarator D. This routine is responsible for checking 780/// that the newly-created constructor declaration is well-formed and 781/// for recording it in the C++ class. Example: 782/// 783/// @code 784/// class X { 785/// X(); // X::X() will be the ConDecl. 786/// }; 787/// @endcode 788Sema::DeclTy *Sema::ActOnConstructorDeclarator(CXXConstructorDecl *ConDecl) { 789 assert(ConDecl && "Expected to receive a constructor declaration"); 790 791 // Check default arguments on the constructor 792 CheckCXXDefaultArguments(ConDecl); 793 794 CXXRecordDecl *ClassDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext); 795 if (!ClassDecl) { 796 ConDecl->setInvalidDecl(); 797 return ConDecl; 798 } 799 800 // Make sure this constructor is an overload of the existing 801 // constructors. 802 OverloadedFunctionDecl::function_iterator MatchedDecl; 803 if (!IsOverload(ConDecl, ClassDecl->getConstructors(), MatchedDecl)) { 804 Diag(ConDecl->getLocation(), 805 diag::err_constructor_redeclared, 806 SourceRange(ConDecl->getLocation())); 807 Diag((*MatchedDecl)->getLocation(), 808 diag::err_previous_declaration, 809 SourceRange((*MatchedDecl)->getLocation())); 810 ConDecl->setInvalidDecl(); 811 return ConDecl; 812 } 813 814 815 // C++ [class.copy]p3: 816 // A declaration of a constructor for a class X is ill-formed if 817 // its first parameter is of type (optionally cv-qualified) X and 818 // either there are no other parameters or else all other 819 // parameters have default arguments. 820 if ((ConDecl->getNumParams() == 1) || 821 (ConDecl->getNumParams() > 1 && 822 ConDecl->getParamDecl(1)->getDefaultArg() != 0)) { 823 QualType ParamType = ConDecl->getParamDecl(0)->getType(); 824 QualType ClassTy = Context.getTagDeclType( 825 const_cast<CXXRecordDecl*>(ConDecl->getParent())); 826 if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) { 827 Diag(ConDecl->getLocation(), 828 diag::err_constructor_byvalue_arg, 829 SourceRange(ConDecl->getParamDecl(0)->getLocation())); 830 ConDecl->setInvalidDecl(); 831 return 0; 832 } 833 } 834 835 // Add this constructor to the set of constructors of the current 836 // class. 837 ClassDecl->addConstructor(Context, ConDecl); 838 839 return (DeclTy *)ConDecl; 840} 841 842//===----------------------------------------------------------------------===// 843// Namespace Handling 844//===----------------------------------------------------------------------===// 845 846/// ActOnStartNamespaceDef - This is called at the start of a namespace 847/// definition. 848Sema::DeclTy *Sema::ActOnStartNamespaceDef(Scope *NamespcScope, 849 SourceLocation IdentLoc, 850 IdentifierInfo *II, 851 SourceLocation LBrace) { 852 NamespaceDecl *Namespc = 853 NamespaceDecl::Create(Context, CurContext, IdentLoc, II); 854 Namespc->setLBracLoc(LBrace); 855 856 Scope *DeclRegionScope = NamespcScope->getParent(); 857 858 if (II) { 859 // C++ [namespace.def]p2: 860 // The identifier in an original-namespace-definition shall not have been 861 // previously defined in the declarative region in which the 862 // original-namespace-definition appears. The identifier in an 863 // original-namespace-definition is the name of the namespace. Subsequently 864 // in that declarative region, it is treated as an original-namespace-name. 865 866 Decl *PrevDecl = 867 LookupDecl(II, Decl::IDNS_Tag | Decl::IDNS_Ordinary, DeclRegionScope, 868 /*enableLazyBuiltinCreation=*/false); 869 870 if (PrevDecl && isDeclInScope(PrevDecl, CurContext, DeclRegionScope)) { 871 if (NamespaceDecl *OrigNS = dyn_cast<NamespaceDecl>(PrevDecl)) { 872 // This is an extended namespace definition. 873 // Attach this namespace decl to the chain of extended namespace 874 // definitions. 875 NamespaceDecl *NextNS = OrigNS; 876 while (NextNS->getNextNamespace()) 877 NextNS = NextNS->getNextNamespace(); 878 879 NextNS->setNextNamespace(Namespc); 880 Namespc->setOriginalNamespace(OrigNS); 881 882 // We won't add this decl to the current scope. We want the namespace 883 // name to return the original namespace decl during a name lookup. 884 } else { 885 // This is an invalid name redefinition. 886 Diag(Namespc->getLocation(), diag::err_redefinition_different_kind, 887 Namespc->getName()); 888 Diag(PrevDecl->getLocation(), diag::err_previous_definition); 889 Namespc->setInvalidDecl(); 890 // Continue on to push Namespc as current DeclContext and return it. 891 } 892 } else { 893 // This namespace name is declared for the first time. 894 PushOnScopeChains(Namespc, DeclRegionScope); 895 } 896 } 897 else { 898 // FIXME: Handle anonymous namespaces 899 } 900 901 // Although we could have an invalid decl (i.e. the namespace name is a 902 // redefinition), push it as current DeclContext and try to continue parsing. 903 PushDeclContext(Namespc->getOriginalNamespace()); 904 return Namespc; 905} 906 907/// ActOnFinishNamespaceDef - This callback is called after a namespace is 908/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef. 909void Sema::ActOnFinishNamespaceDef(DeclTy *D, SourceLocation RBrace) { 910 Decl *Dcl = static_cast<Decl *>(D); 911 NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl); 912 assert(Namespc && "Invalid parameter, expected NamespaceDecl"); 913 Namespc->setRBracLoc(RBrace); 914 PopDeclContext(); 915} 916 917 918/// AddCXXDirectInitializerToDecl - This action is called immediately after 919/// ActOnDeclarator, when a C++ direct initializer is present. 920/// e.g: "int x(1);" 921void Sema::AddCXXDirectInitializerToDecl(DeclTy *Dcl, SourceLocation LParenLoc, 922 ExprTy **ExprTys, unsigned NumExprs, 923 SourceLocation *CommaLocs, 924 SourceLocation RParenLoc) { 925 assert(NumExprs != 0 && ExprTys && "missing expressions"); 926 Decl *RealDecl = static_cast<Decl *>(Dcl); 927 928 // If there is no declaration, there was an error parsing it. Just ignore 929 // the initializer. 930 if (RealDecl == 0) { 931 for (unsigned i = 0; i != NumExprs; ++i) 932 delete static_cast<Expr *>(ExprTys[i]); 933 return; 934 } 935 936 VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl); 937 if (!VDecl) { 938 Diag(RealDecl->getLocation(), diag::err_illegal_initializer); 939 RealDecl->setInvalidDecl(); 940 return; 941 } 942 943 // We will treat direct-initialization as a copy-initialization: 944 // int x(1); -as-> int x = 1; 945 // ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c); 946 // 947 // Clients that want to distinguish between the two forms, can check for 948 // direct initializer using VarDecl::hasCXXDirectInitializer(). 949 // A major benefit is that clients that don't particularly care about which 950 // exactly form was it (like the CodeGen) can handle both cases without 951 // special case code. 952 953 // C++ 8.5p11: 954 // The form of initialization (using parentheses or '=') is generally 955 // insignificant, but does matter when the entity being initialized has a 956 // class type. 957 QualType DeclInitType = VDecl->getType(); 958 if (const ArrayType *Array = Context.getAsArrayType(DeclInitType)) 959 DeclInitType = Array->getElementType(); 960 961 if (VDecl->getType()->isRecordType()) { 962 CXXConstructorDecl *Constructor 963 = PerformDirectInitForClassType(DeclInitType, (Expr **)ExprTys, NumExprs, 964 VDecl->getLocation(), 965 SourceRange(VDecl->getLocation(), 966 RParenLoc), 967 VDecl->getName(), 968 /*HasInitializer=*/true); 969 if (!Constructor) { 970 RealDecl->setInvalidDecl(); 971 } 972 return; 973 } 974 975 if (NumExprs > 1) { 976 Diag(CommaLocs[0], diag::err_builtin_direct_init_more_than_one_arg, 977 SourceRange(VDecl->getLocation(), RParenLoc)); 978 RealDecl->setInvalidDecl(); 979 return; 980 } 981 982 // Let clients know that initialization was done with a direct initializer. 983 VDecl->setCXXDirectInitializer(true); 984 985 assert(NumExprs == 1 && "Expected 1 expression"); 986 // Set the init expression, handles conversions. 987 AddInitializerToDecl(Dcl, ExprTys[0]); 988} 989 990/// PerformDirectInitForClassType - Perform direct-initialization (C++ 991/// [dcl.init]) for a value of the given class type with the given set 992/// of arguments (@p Args). @p Loc is the location in the source code 993/// where the initializer occurs (e.g., a declaration, member 994/// initializer, functional cast, etc.) while @p Range covers the 995/// whole initialization. @p HasInitializer is true if the initializer 996/// was actually written in the source code. When successful, returns 997/// the constructor that will be used to perform the initialization; 998/// when the initialization fails, emits a diagnostic and returns null. 999CXXConstructorDecl * 1000Sema::PerformDirectInitForClassType(QualType ClassType, 1001 Expr **Args, unsigned NumArgs, 1002 SourceLocation Loc, SourceRange Range, 1003 std::string InitEntity, 1004 bool HasInitializer) { 1005 const RecordType *ClassRec = ClassType->getAsRecordType(); 1006 assert(ClassRec && "Can only initialize a class type here"); 1007 1008 // C++ [dcl.init]p14: 1009 // 1010 // If the initialization is direct-initialization, or if it is 1011 // copy-initialization where the cv-unqualified version of the 1012 // source type is the same class as, or a derived class of, the 1013 // class of the destination, constructors are considered. The 1014 // applicable constructors are enumerated (13.3.1.3), and the 1015 // best one is chosen through overload resolution (13.3). The 1016 // constructor so selected is called to initialize the object, 1017 // with the initializer expression(s) as its argument(s). If no 1018 // constructor applies, or the overload resolution is ambiguous, 1019 // the initialization is ill-formed. 1020 // 1021 // FIXME: We don't check cv-qualifiers on the class type, because we 1022 // don't yet keep track of whether a class type is a POD class type 1023 // (or a "trivial" class type, as is used in C++0x). 1024 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassRec->getDecl()); 1025 OverloadCandidateSet CandidateSet; 1026 OverloadCandidateSet::iterator Best; 1027 AddOverloadCandidates(ClassDecl->getConstructors(), Args, NumArgs, 1028 CandidateSet); 1029 switch (BestViableFunction(CandidateSet, Best)) { 1030 case OR_Success: 1031 // We found a constructor. Return it. 1032 return cast<CXXConstructorDecl>(Best->Function); 1033 1034 case OR_No_Viable_Function: 1035 if (CandidateSet.empty()) 1036 Diag(Loc, diag::err_ovl_no_viable_function_in_init, 1037 InitEntity, Range); 1038 else { 1039 Diag(Loc, diag::err_ovl_no_viable_function_in_init_with_cands, 1040 InitEntity, Range); 1041 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 1042 } 1043 return 0; 1044 1045 case OR_Ambiguous: 1046 Diag(Loc, diag::err_ovl_ambiguous_init, 1047 InitEntity, Range); 1048 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 1049 return 0; 1050 } 1051 1052 return 0; 1053} 1054 1055/// CompareReferenceRelationship - Compare the two types T1 and T2 to 1056/// determine whether they are reference-related, 1057/// reference-compatible, reference-compatible with added 1058/// qualification, or incompatible, for use in C++ initialization by 1059/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 1060/// type, and the first type (T1) is the pointee type of the reference 1061/// type being initialized. 1062Sema::ReferenceCompareResult 1063Sema::CompareReferenceRelationship(QualType T1, QualType T2, 1064 bool& DerivedToBase) { 1065 assert(!T1->isReferenceType() && "T1 must be the pointee type of the reference type"); 1066 assert(!T2->isReferenceType() && "T2 cannot be a reference type"); 1067 1068 T1 = Context.getCanonicalType(T1); 1069 T2 = Context.getCanonicalType(T2); 1070 QualType UnqualT1 = T1.getUnqualifiedType(); 1071 QualType UnqualT2 = T2.getUnqualifiedType(); 1072 1073 // C++ [dcl.init.ref]p4: 1074 // Given types “cv1 T1” and “cv2 T2,” “cv1 T1” is 1075 // reference-related to “cv2 T2” if T1 is the same type as T2, or 1076 // T1 is a base class of T2. 1077 if (UnqualT1 == UnqualT2) 1078 DerivedToBase = false; 1079 else if (IsDerivedFrom(UnqualT2, UnqualT1)) 1080 DerivedToBase = true; 1081 else 1082 return Ref_Incompatible; 1083 1084 // At this point, we know that T1 and T2 are reference-related (at 1085 // least). 1086 1087 // C++ [dcl.init.ref]p4: 1088 // "cv1 T1” is reference-compatible with “cv2 T2” if T1 is 1089 // reference-related to T2 and cv1 is the same cv-qualification 1090 // as, or greater cv-qualification than, cv2. For purposes of 1091 // overload resolution, cases for which cv1 is greater 1092 // cv-qualification than cv2 are identified as 1093 // reference-compatible with added qualification (see 13.3.3.2). 1094 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1095 return Ref_Compatible; 1096 else if (T1.isMoreQualifiedThan(T2)) 1097 return Ref_Compatible_With_Added_Qualification; 1098 else 1099 return Ref_Related; 1100} 1101 1102/// CheckReferenceInit - Check the initialization of a reference 1103/// variable with the given initializer (C++ [dcl.init.ref]). Init is 1104/// the initializer (either a simple initializer or an initializer 1105/// list), and DeclType is the type of the declaration. When ICS is 1106/// non-null, this routine will compute the implicit conversion 1107/// sequence according to C++ [over.ics.ref] and will not produce any 1108/// diagnostics; when ICS is null, it will emit diagnostics when any 1109/// errors are found. Either way, a return value of true indicates 1110/// that there was a failure, a return value of false indicates that 1111/// the reference initialization succeeded. 1112/// 1113/// When @p SuppressUserConversions, user-defined conversions are 1114/// suppressed. 1115bool 1116Sema::CheckReferenceInit(Expr *&Init, QualType &DeclType, 1117 ImplicitConversionSequence *ICS, 1118 bool SuppressUserConversions) { 1119 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 1120 1121 QualType T1 = DeclType->getAsReferenceType()->getPointeeType(); 1122 QualType T2 = Init->getType(); 1123 1124 // Compute some basic properties of the types and the initializer. 1125 bool DerivedToBase = false; 1126 Expr::isLvalueResult InitLvalue = Init->isLvalue(Context); 1127 ReferenceCompareResult RefRelationship 1128 = CompareReferenceRelationship(T1, T2, DerivedToBase); 1129 1130 // Most paths end in a failed conversion. 1131 if (ICS) 1132 ICS->ConversionKind = ImplicitConversionSequence::BadConversion; 1133 1134 // C++ [dcl.init.ref]p5: 1135 // A reference to type “cv1 T1” is initialized by an expression 1136 // of type “cv2 T2” as follows: 1137 1138 // -- If the initializer expression 1139 1140 bool BindsDirectly = false; 1141 // -- is an lvalue (but is not a bit-field), and “cv1 T1” is 1142 // reference-compatible with “cv2 T2,” or 1143 // 1144 // Note that the bit-field check is skipped if we are just computing 1145 // the implicit conversion sequence (C++ [over.best.ics]p2). 1146 if (InitLvalue == Expr::LV_Valid && (ICS || !Init->isBitField()) && 1147 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1148 BindsDirectly = true; 1149 1150 if (ICS) { 1151 // C++ [over.ics.ref]p1: 1152 // When a parameter of reference type binds directly (8.5.3) 1153 // to an argument expression, the implicit conversion sequence 1154 // is the identity conversion, unless the argument expression 1155 // has a type that is a derived class of the parameter type, 1156 // in which case the implicit conversion sequence is a 1157 // derived-to-base Conversion (13.3.3.1). 1158 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1159 ICS->Standard.First = ICK_Identity; 1160 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1161 ICS->Standard.Third = ICK_Identity; 1162 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1163 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1164 ICS->Standard.ReferenceBinding = true; 1165 ICS->Standard.DirectBinding = true; 1166 1167 // Nothing more to do: the inaccessibility/ambiguity check for 1168 // derived-to-base conversions is suppressed when we're 1169 // computing the implicit conversion sequence (C++ 1170 // [over.best.ics]p2). 1171 return false; 1172 } else { 1173 // Perform the conversion. 1174 // FIXME: Binding to a subobject of the lvalue is going to require 1175 // more AST annotation than this. 1176 ImpCastExprToType(Init, T1); 1177 } 1178 } 1179 1180 // -- has a class type (i.e., T2 is a class type) and can be 1181 // implicitly converted to an lvalue of type “cv3 T3,” 1182 // where “cv1 T1” is reference-compatible with “cv3 T3” 1183 // 92) (this conversion is selected by enumerating the 1184 // applicable conversion functions (13.3.1.6) and choosing 1185 // the best one through overload resolution (13.3)), 1186 // FIXME: Implement this second bullet, once we have conversion 1187 // functions. Also remember C++ [over.ics.ref]p1, second part. 1188 1189 if (BindsDirectly) { 1190 // C++ [dcl.init.ref]p4: 1191 // [...] In all cases where the reference-related or 1192 // reference-compatible relationship of two types is used to 1193 // establish the validity of a reference binding, and T1 is a 1194 // base class of T2, a program that necessitates such a binding 1195 // is ill-formed if T1 is an inaccessible (clause 11) or 1196 // ambiguous (10.2) base class of T2. 1197 // 1198 // Note that we only check this condition when we're allowed to 1199 // complain about errors, because we should not be checking for 1200 // ambiguity (or inaccessibility) unless the reference binding 1201 // actually happens. 1202 if (DerivedToBase) 1203 return CheckDerivedToBaseConversion(T2, T1, 1204 Init->getSourceRange().getBegin(), 1205 Init->getSourceRange()); 1206 else 1207 return false; 1208 } 1209 1210 // -- Otherwise, the reference shall be to a non-volatile const 1211 // type (i.e., cv1 shall be const). 1212 if (T1.getCVRQualifiers() != QualType::Const) { 1213 if (!ICS) 1214 Diag(Init->getSourceRange().getBegin(), 1215 diag::err_not_reference_to_const_init, 1216 T1.getAsString(), 1217 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1218 T2.getAsString(), Init->getSourceRange()); 1219 return true; 1220 } 1221 1222 // -- If the initializer expression is an rvalue, with T2 a 1223 // class type, and “cv1 T1” is reference-compatible with 1224 // “cv2 T2,” the reference is bound in one of the 1225 // following ways (the choice is implementation-defined): 1226 // 1227 // -- The reference is bound to the object represented by 1228 // the rvalue (see 3.10) or to a sub-object within that 1229 // object. 1230 // 1231 // -- A temporary of type “cv1 T2” [sic] is created, and 1232 // a constructor is called to copy the entire rvalue 1233 // object into the temporary. The reference is bound to 1234 // the temporary or to a sub-object within the 1235 // temporary. 1236 // 1237 // 1238 // The constructor that would be used to make the copy 1239 // shall be callable whether or not the copy is actually 1240 // done. 1241 // 1242 // Note that C++0x [dcl.ref.init]p5 takes away this implementation 1243 // freedom, so we will always take the first option and never build 1244 // a temporary in this case. FIXME: We will, however, have to check 1245 // for the presence of a copy constructor in C++98/03 mode. 1246 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 1247 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1248 if (ICS) { 1249 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1250 ICS->Standard.First = ICK_Identity; 1251 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1252 ICS->Standard.Third = ICK_Identity; 1253 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1254 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1255 ICS->Standard.ReferenceBinding = true; 1256 ICS->Standard.DirectBinding = false; 1257 } else { 1258 // FIXME: Binding to a subobject of the rvalue is going to require 1259 // more AST annotation than this. 1260 ImpCastExprToType(Init, T1); 1261 } 1262 return false; 1263 } 1264 1265 // -- Otherwise, a temporary of type “cv1 T1” is created and 1266 // initialized from the initializer expression using the 1267 // rules for a non-reference copy initialization (8.5). The 1268 // reference is then bound to the temporary. If T1 is 1269 // reference-related to T2, cv1 must be the same 1270 // cv-qualification as, or greater cv-qualification than, 1271 // cv2; otherwise, the program is ill-formed. 1272 if (RefRelationship == Ref_Related) { 1273 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 1274 // we would be reference-compatible or reference-compatible with 1275 // added qualification. But that wasn't the case, so the reference 1276 // initialization fails. 1277 if (!ICS) 1278 Diag(Init->getSourceRange().getBegin(), 1279 diag::err_reference_init_drops_quals, 1280 T1.getAsString(), 1281 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1282 T2.getAsString(), Init->getSourceRange()); 1283 return true; 1284 } 1285 1286 // Actually try to convert the initializer to T1. 1287 if (ICS) { 1288 /// C++ [over.ics.ref]p2: 1289 /// 1290 /// When a parameter of reference type is not bound directly to 1291 /// an argument expression, the conversion sequence is the one 1292 /// required to convert the argument expression to the 1293 /// underlying type of the reference according to 1294 /// 13.3.3.1. Conceptually, this conversion sequence corresponds 1295 /// to copy-initializing a temporary of the underlying type with 1296 /// the argument expression. Any difference in top-level 1297 /// cv-qualification is subsumed by the initialization itself 1298 /// and does not constitute a conversion. 1299 *ICS = TryImplicitConversion(Init, T1, SuppressUserConversions); 1300 return ICS->ConversionKind == ImplicitConversionSequence::BadConversion; 1301 } else { 1302 return PerformImplicitConversion(Init, T1); 1303 } 1304} 1305