SemaDeclCXX.cpp revision 58c428c96934a7873e70eadde8b496ff7f8d72ec
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 bool VisitPredefinedExpr(PredefinedExpr *PE); 50 }; 51 52 /// VisitExpr - Visit all of the children of this expression. 53 bool CheckDefaultArgumentVisitor::VisitExpr(Expr *Node) { 54 bool IsInvalid = false; 55 for (Stmt::child_iterator I = Node->child_begin(), 56 E = Node->child_end(); I != E; ++I) 57 IsInvalid |= Visit(*I); 58 return IsInvalid; 59 } 60 61 /// VisitDeclRefExpr - Visit a reference to a declaration, to 62 /// determine whether this declaration can be used in the default 63 /// argument expression. 64 bool CheckDefaultArgumentVisitor::VisitDeclRefExpr(DeclRefExpr *DRE) { 65 NamedDecl *Decl = DRE->getDecl(); 66 if (ParmVarDecl *Param = dyn_cast<ParmVarDecl>(Decl)) { 67 // C++ [dcl.fct.default]p9 68 // Default arguments are evaluated each time the function is 69 // called. The order of evaluation of function arguments is 70 // unspecified. Consequently, parameters of a function shall not 71 // be used in default argument expressions, even if they are not 72 // evaluated. Parameters of a function declared before a default 73 // argument expression are in scope and can hide namespace and 74 // class member names. 75 return S->Diag(DRE->getSourceRange().getBegin(), 76 diag::err_param_default_argument_references_param, 77 Param->getName(), DefaultArg->getSourceRange()); 78 } else if (VarDecl *VDecl = dyn_cast<VarDecl>(Decl)) { 79 // C++ [dcl.fct.default]p7 80 // Local variables shall not be used in default argument 81 // expressions. 82 if (VDecl->isBlockVarDecl()) 83 return S->Diag(DRE->getSourceRange().getBegin(), 84 diag::err_param_default_argument_references_local, 85 VDecl->getName(), DefaultArg->getSourceRange()); 86 } 87 88 return false; 89 } 90 91 /// VisitPredefinedExpr - Visit a predefined expression, which could 92 /// refer to "this". 93 bool CheckDefaultArgumentVisitor::VisitPredefinedExpr(PredefinedExpr *PE) { 94 if (PE->getIdentType() == PredefinedExpr::CXXThis) { 95 // C++ [dcl.fct.default]p8: 96 // The keyword this shall not be used in a default argument of a 97 // member function. 98 return S->Diag(PE->getSourceRange().getBegin(), 99 diag::err_param_default_argument_references_this, 100 PE->getSourceRange()); 101 } 102 return false; 103 } 104} 105 106/// ActOnParamDefaultArgument - Check whether the default argument 107/// provided for a function parameter is well-formed. If so, attach it 108/// to the parameter declaration. 109void 110Sema::ActOnParamDefaultArgument(DeclTy *param, SourceLocation EqualLoc, 111 ExprTy *defarg) { 112 ParmVarDecl *Param = (ParmVarDecl *)param; 113 llvm::OwningPtr<Expr> DefaultArg((Expr *)defarg); 114 QualType ParamType = Param->getType(); 115 116 // Default arguments are only permitted in C++ 117 if (!getLangOptions().CPlusPlus) { 118 Diag(EqualLoc, diag::err_param_default_argument, 119 DefaultArg->getSourceRange()); 120 return; 121 } 122 123 // C++ [dcl.fct.default]p5 124 // A default argument expression is implicitly converted (clause 125 // 4) to the parameter type. The default argument expression has 126 // the same semantic constraints as the initializer expression in 127 // a declaration of a variable of the parameter type, using the 128 // copy-initialization semantics (8.5). 129 Expr *DefaultArgPtr = DefaultArg.get(); 130 bool DefaultInitFailed = PerformCopyInitialization(DefaultArgPtr, ParamType, 131 "in default argument"); 132 if (DefaultArgPtr != DefaultArg.get()) { 133 DefaultArg.take(); 134 DefaultArg.reset(DefaultArgPtr); 135 } 136 if (DefaultInitFailed) { 137 return; 138 } 139 140 // Check that the default argument is well-formed 141 CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this); 142 if (DefaultArgChecker.Visit(DefaultArg.get())) 143 return; 144 145 // Okay: add the default argument to the parameter 146 Param->setDefaultArg(DefaultArg.take()); 147} 148 149/// CheckExtraCXXDefaultArguments - Check for any extra default 150/// arguments in the declarator, which is not a function declaration 151/// or definition and therefore is not permitted to have default 152/// arguments. This routine should be invoked for every declarator 153/// that is not a function declaration or definition. 154void Sema::CheckExtraCXXDefaultArguments(Declarator &D) { 155 // C++ [dcl.fct.default]p3 156 // A default argument expression shall be specified only in the 157 // parameter-declaration-clause of a function declaration or in a 158 // template-parameter (14.1). It shall not be specified for a 159 // parameter pack. If it is specified in a 160 // parameter-declaration-clause, it shall not occur within a 161 // declarator or abstract-declarator of a parameter-declaration. 162 for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) { 163 DeclaratorChunk &chunk = D.getTypeObject(i); 164 if (chunk.Kind == DeclaratorChunk::Function) { 165 for (unsigned argIdx = 0; argIdx < chunk.Fun.NumArgs; ++argIdx) { 166 ParmVarDecl *Param = (ParmVarDecl *)chunk.Fun.ArgInfo[argIdx].Param; 167 if (Param->getDefaultArg()) { 168 Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc, 169 Param->getDefaultArg()->getSourceRange()); 170 Param->setDefaultArg(0); 171 } 172 } 173 } 174 } 175} 176 177// MergeCXXFunctionDecl - Merge two declarations of the same C++ 178// function, once we already know that they have the same 179// type. Subroutine of MergeFunctionDecl. 180FunctionDecl * 181Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) { 182 // C++ [dcl.fct.default]p4: 183 // 184 // For non-template functions, default arguments can be added in 185 // later declarations of a function in the same 186 // scope. Declarations in different scopes have completely 187 // distinct sets of default arguments. That is, declarations in 188 // inner scopes do not acquire default arguments from 189 // declarations in outer scopes, and vice versa. In a given 190 // function declaration, all parameters subsequent to a 191 // parameter with a default argument shall have default 192 // arguments supplied in this or previous declarations. A 193 // default argument shall not be redefined by a later 194 // declaration (not even to the same value). 195 for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) { 196 ParmVarDecl *OldParam = Old->getParamDecl(p); 197 ParmVarDecl *NewParam = New->getParamDecl(p); 198 199 if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) { 200 Diag(NewParam->getLocation(), 201 diag::err_param_default_argument_redefinition, 202 NewParam->getDefaultArg()->getSourceRange()); 203 Diag(OldParam->getLocation(), diag::err_previous_definition); 204 } else if (OldParam->getDefaultArg()) { 205 // Merge the old default argument into the new parameter 206 NewParam->setDefaultArg(OldParam->getDefaultArg()); 207 } 208 } 209 210 return New; 211} 212 213/// CheckCXXDefaultArguments - Verify that the default arguments for a 214/// function declaration are well-formed according to C++ 215/// [dcl.fct.default]. 216void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) { 217 unsigned NumParams = FD->getNumParams(); 218 unsigned p; 219 220 // Find first parameter with a default argument 221 for (p = 0; p < NumParams; ++p) { 222 ParmVarDecl *Param = FD->getParamDecl(p); 223 if (Param->getDefaultArg()) 224 break; 225 } 226 227 // C++ [dcl.fct.default]p4: 228 // In a given function declaration, all parameters 229 // subsequent to a parameter with a default argument shall 230 // have default arguments supplied in this or previous 231 // declarations. A default argument shall not be redefined 232 // by a later declaration (not even to the same value). 233 unsigned LastMissingDefaultArg = 0; 234 for(; p < NumParams; ++p) { 235 ParmVarDecl *Param = FD->getParamDecl(p); 236 if (!Param->getDefaultArg()) { 237 if (Param->getIdentifier()) 238 Diag(Param->getLocation(), 239 diag::err_param_default_argument_missing_name, 240 Param->getIdentifier()->getName()); 241 else 242 Diag(Param->getLocation(), 243 diag::err_param_default_argument_missing); 244 245 LastMissingDefaultArg = p; 246 } 247 } 248 249 if (LastMissingDefaultArg > 0) { 250 // Some default arguments were missing. Clear out all of the 251 // default arguments up to (and including) the last missing 252 // default argument, so that we leave the function parameters 253 // in a semantically valid state. 254 for (p = 0; p <= LastMissingDefaultArg; ++p) { 255 ParmVarDecl *Param = FD->getParamDecl(p); 256 if (Param->getDefaultArg()) { 257 delete Param->getDefaultArg(); 258 Param->setDefaultArg(0); 259 } 260 } 261 } 262} 263 264/// isCurrentClassName - Determine whether the identifier II is the 265/// name of the class type currently being defined. In the case of 266/// nested classes, this will only return true if II is the name of 267/// the innermost class. 268bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *) { 269 if (CXXRecordDecl *CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext)) 270 return &II == CurDecl->getIdentifier(); 271 else 272 return false; 273} 274 275/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is 276/// one entry in the base class list of a class specifier, for 277/// example: 278/// class foo : public bar, virtual private baz { 279/// 'public bar' and 'virtual private baz' are each base-specifiers. 280Sema::BaseResult 281Sema::ActOnBaseSpecifier(DeclTy *classdecl, SourceRange SpecifierRange, 282 bool Virtual, AccessSpecifier Access, 283 TypeTy *basetype, SourceLocation BaseLoc) { 284 RecordDecl *Decl = (RecordDecl*)classdecl; 285 QualType BaseType = Context.getTypeDeclType((TypeDecl*)basetype); 286 287 // Base specifiers must be record types. 288 if (!BaseType->isRecordType()) { 289 Diag(BaseLoc, diag::err_base_must_be_class, SpecifierRange); 290 return true; 291 } 292 293 // C++ [class.union]p1: 294 // A union shall not be used as a base class. 295 if (BaseType->isUnionType()) { 296 Diag(BaseLoc, diag::err_union_as_base_class, SpecifierRange); 297 return true; 298 } 299 300 // C++ [class.union]p1: 301 // A union shall not have base classes. 302 if (Decl->isUnion()) { 303 Diag(Decl->getLocation(), diag::err_base_clause_on_union, 304 SpecifierRange); 305 return true; 306 } 307 308 // C++ [class.derived]p2: 309 // The class-name in a base-specifier shall not be an incompletely 310 // defined class. 311 if (BaseType->isIncompleteType()) { 312 Diag(BaseLoc, diag::err_incomplete_base_class, SpecifierRange); 313 return true; 314 } 315 316 // Create the base specifier. 317 return new CXXBaseSpecifier(SpecifierRange, Virtual, 318 BaseType->isClassType(), Access, BaseType); 319} 320 321/// ActOnBaseSpecifiers - Attach the given base specifiers to the 322/// class, after checking whether there are any duplicate base 323/// classes. 324void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases, 325 unsigned NumBases) { 326 if (NumBases == 0) 327 return; 328 329 // Used to keep track of which base types we have already seen, so 330 // that we can properly diagnose redundant direct base types. Note 331 // that the key is always the unqualified canonical type of the base 332 // class. 333 std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes; 334 335 // Copy non-redundant base specifiers into permanent storage. 336 CXXBaseSpecifier **BaseSpecs = (CXXBaseSpecifier **)Bases; 337 unsigned NumGoodBases = 0; 338 for (unsigned idx = 0; idx < NumBases; ++idx) { 339 QualType NewBaseType 340 = Context.getCanonicalType(BaseSpecs[idx]->getType()); 341 NewBaseType = NewBaseType.getUnqualifiedType(); 342 343 if (KnownBaseTypes[NewBaseType]) { 344 // C++ [class.mi]p3: 345 // A class shall not be specified as a direct base class of a 346 // derived class more than once. 347 Diag(BaseSpecs[idx]->getSourceRange().getBegin(), 348 diag::err_duplicate_base_class, 349 KnownBaseTypes[NewBaseType]->getType().getAsString(), 350 BaseSpecs[idx]->getSourceRange()); 351 352 // Delete the duplicate base class specifier; we're going to 353 // overwrite its pointer later. 354 delete BaseSpecs[idx]; 355 } else { 356 // Okay, add this new base class. 357 KnownBaseTypes[NewBaseType] = BaseSpecs[idx]; 358 BaseSpecs[NumGoodBases++] = BaseSpecs[idx]; 359 } 360 } 361 362 // Attach the remaining base class specifiers to the derived class. 363 CXXRecordDecl *Decl = (CXXRecordDecl*)ClassDecl; 364 Decl->setBases(BaseSpecs, NumGoodBases); 365 366 // Delete the remaining (good) base class specifiers, since their 367 // data has been copied into the CXXRecordDecl. 368 for (unsigned idx = 0; idx < NumGoodBases; ++idx) 369 delete BaseSpecs[idx]; 370} 371 372//===----------------------------------------------------------------------===// 373// C++ class member Handling 374//===----------------------------------------------------------------------===// 375 376/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union 377/// definition, when on C++. 378void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) { 379 CXXRecordDecl *Dcl = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 380 PushDeclContext(Dcl); 381 FieldCollector->StartClass(); 382 383 if (Dcl->getIdentifier()) { 384 // C++ [class]p2: 385 // [...] The class-name is also inserted into the scope of the 386 // class itself; this is known as the injected-class-name. For 387 // purposes of access checking, the injected-class-name is treated 388 // as if it were a public member name. 389 TypedefDecl *InjectedClassName 390 = TypedefDecl::Create(Context, Dcl, LBrace, Dcl->getIdentifier(), 391 Context.getTypeDeclType(Dcl), /*PrevDecl=*/0); 392 PushOnScopeChains(InjectedClassName, S); 393 } 394} 395 396/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member 397/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the 398/// bitfield width if there is one and 'InitExpr' specifies the initializer if 399/// any. 'LastInGroup' is non-null for cases where one declspec has multiple 400/// declarators on it. 401/// 402/// NOTE: Because of CXXFieldDecl's inability to be chained like ScopedDecls, if 403/// an instance field is declared, a new CXXFieldDecl is created but the method 404/// does *not* return it; it returns LastInGroup instead. The other C++ members 405/// (which are all ScopedDecls) are returned after appending them to 406/// LastInGroup. 407Sema::DeclTy * 408Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D, 409 ExprTy *BW, ExprTy *InitExpr, 410 DeclTy *LastInGroup) { 411 const DeclSpec &DS = D.getDeclSpec(); 412 IdentifierInfo *II = D.getIdentifier(); 413 Expr *BitWidth = static_cast<Expr*>(BW); 414 Expr *Init = static_cast<Expr*>(InitExpr); 415 SourceLocation Loc = D.getIdentifierLoc(); 416 417 // C++ 9.2p6: A member shall not be declared to have automatic storage 418 // duration (auto, register) or with the extern storage-class-specifier. 419 switch (DS.getStorageClassSpec()) { 420 case DeclSpec::SCS_unspecified: 421 case DeclSpec::SCS_typedef: 422 case DeclSpec::SCS_static: 423 // FALL THROUGH. 424 break; 425 default: 426 if (DS.getStorageClassSpecLoc().isValid()) 427 Diag(DS.getStorageClassSpecLoc(), 428 diag::err_storageclass_invalid_for_member); 429 else 430 Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member); 431 D.getMutableDeclSpec().ClearStorageClassSpecs(); 432 } 433 434 bool isFunc = D.isFunctionDeclarator(); 435 if (!isFunc && 436 D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef && 437 D.getNumTypeObjects() == 0) { 438 // Check also for this case: 439 // 440 // typedef int f(); 441 // f a; 442 // 443 Decl *TD = static_cast<Decl *>(DS.getTypeRep()); 444 isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType(); 445 } 446 447 bool isInstField = (DS.getStorageClassSpec() == DeclSpec::SCS_unspecified && 448 !isFunc); 449 450 Decl *Member; 451 bool InvalidDecl = false; 452 453 if (isInstField) 454 Member = static_cast<Decl*>(ActOnField(S, Loc, D, BitWidth)); 455 else 456 Member = static_cast<Decl*>(ActOnDeclarator(S, D, LastInGroup)); 457 458 if (!Member) return LastInGroup; 459 460 assert((II || isInstField) && "No identifier for non-field ?"); 461 462 // set/getAccess is not part of Decl's interface to avoid bloating it with C++ 463 // specific methods. Use a wrapper class that can be used with all C++ class 464 // member decls. 465 CXXClassMemberWrapper(Member).setAccess(AS); 466 467 if (BitWidth) { 468 // C++ 9.6p2: Only when declaring an unnamed bit-field may the 469 // constant-expression be a value equal to zero. 470 // FIXME: Check this. 471 472 if (D.isFunctionDeclarator()) { 473 // FIXME: Emit diagnostic about only constructors taking base initializers 474 // or something similar, when constructor support is in place. 475 Diag(Loc, diag::err_not_bitfield_type, 476 II->getName(), BitWidth->getSourceRange()); 477 InvalidDecl = true; 478 479 } else if (isInstField) { 480 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 481 if (!cast<FieldDecl>(Member)->getType()->isIntegralType()) { 482 Diag(Loc, diag::err_not_integral_type_bitfield, 483 II->getName(), BitWidth->getSourceRange()); 484 InvalidDecl = true; 485 } 486 487 } else if (isa<FunctionDecl>(Member)) { 488 // A function typedef ("typedef int f(); f a;"). 489 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 490 Diag(Loc, diag::err_not_integral_type_bitfield, 491 II->getName(), BitWidth->getSourceRange()); 492 InvalidDecl = true; 493 494 } else if (isa<TypedefDecl>(Member)) { 495 // "cannot declare 'A' to be a bit-field type" 496 Diag(Loc, diag::err_not_bitfield_type, II->getName(), 497 BitWidth->getSourceRange()); 498 InvalidDecl = true; 499 500 } else { 501 assert(isa<CXXClassVarDecl>(Member) && 502 "Didn't we cover all member kinds?"); 503 // C++ 9.6p3: A bit-field shall not be a static member. 504 // "static member 'A' cannot be a bit-field" 505 Diag(Loc, diag::err_static_not_bitfield, II->getName(), 506 BitWidth->getSourceRange()); 507 InvalidDecl = true; 508 } 509 } 510 511 if (Init) { 512 // C++ 9.2p4: A member-declarator can contain a constant-initializer only 513 // if it declares a static member of const integral or const enumeration 514 // type. 515 if (CXXClassVarDecl *CVD = dyn_cast<CXXClassVarDecl>(Member)) { 516 // ...static member of... 517 CVD->setInit(Init); 518 // ...const integral or const enumeration type. 519 if (Context.getCanonicalType(CVD->getType()).isConstQualified() && 520 CVD->getType()->isIntegralType()) { 521 // constant-initializer 522 if (CheckForConstantInitializer(Init, CVD->getType())) 523 InvalidDecl = true; 524 525 } else { 526 // not const integral. 527 Diag(Loc, diag::err_member_initialization, 528 II->getName(), Init->getSourceRange()); 529 InvalidDecl = true; 530 } 531 532 } else { 533 // not static member. 534 Diag(Loc, diag::err_member_initialization, 535 II->getName(), Init->getSourceRange()); 536 InvalidDecl = true; 537 } 538 } 539 540 if (InvalidDecl) 541 Member->setInvalidDecl(); 542 543 if (isInstField) { 544 FieldCollector->Add(cast<CXXFieldDecl>(Member)); 545 return LastInGroup; 546 } 547 return Member; 548} 549 550void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc, 551 DeclTy *TagDecl, 552 SourceLocation LBrac, 553 SourceLocation RBrac) { 554 ActOnFields(S, RLoc, TagDecl, 555 (DeclTy**)FieldCollector->getCurFields(), 556 FieldCollector->getCurNumFields(), LBrac, RBrac, 0); 557} 558 559/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared 560/// special functions, such as the default constructor, copy 561/// constructor, or destructor, to the given C++ class (C++ 562/// [special]p1). This routine can only be executed just before the 563/// definition of the class is complete. 564void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) { 565 if (!ClassDecl->hasUserDeclaredConstructor()) { 566 // C++ [class.ctor]p5: 567 // A default constructor for a class X is a constructor of class X 568 // that can be called without an argument. If there is no 569 // user-declared constructor for class X, a default constructor is 570 // implicitly declared. An implicitly-declared default constructor 571 // is an inline public member of its class. 572 CXXConstructorDecl *DefaultCon = 573 CXXConstructorDecl::Create(Context, ClassDecl, 574 ClassDecl->getLocation(), 575 ClassDecl->getIdentifier(), 576 Context.getFunctionType(Context.VoidTy, 577 0, 0, false, 0), 578 /*isExplicit=*/false, 579 /*isInline=*/true, 580 /*isImplicitlyDeclared=*/true); 581 DefaultCon->setAccess(AS_public); 582 ClassDecl->addConstructor(Context, DefaultCon); 583 } 584 585 if (!ClassDecl->hasUserDeclaredCopyConstructor()) { 586 // C++ [class.copy]p4: 587 // If the class definition does not explicitly declare a copy 588 // constructor, one is declared implicitly. 589 590 // C++ [class.copy]p5: 591 // The implicitly-declared copy constructor for a class X will 592 // have the form 593 // 594 // X::X(const X&) 595 // 596 // if 597 bool HasConstCopyConstructor = true; 598 599 // -- each direct or virtual base class B of X has a copy 600 // constructor whose first parameter is of type const B& or 601 // const volatile B&, and 602 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 603 HasConstCopyConstructor && Base != ClassDecl->bases_end(); ++Base) { 604 const CXXRecordDecl *BaseClassDecl 605 = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl()); 606 HasConstCopyConstructor 607 = BaseClassDecl->hasConstCopyConstructor(Context); 608 } 609 610 // -- for all the nonstatic data members of X that are of a 611 // class type M (or array thereof), each such class type 612 // has a copy constructor whose first parameter is of type 613 // const M& or const volatile M&. 614 for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(); 615 HasConstCopyConstructor && Field != ClassDecl->field_end(); ++Field) { 616 QualType FieldType = (*Field)->getType(); 617 if (const ArrayType *Array = Context.getAsArrayType(FieldType)) 618 FieldType = Array->getElementType(); 619 if (const RecordType *FieldClassType = FieldType->getAsRecordType()) { 620 const CXXRecordDecl *FieldClassDecl 621 = cast<CXXRecordDecl>(FieldClassType->getDecl()); 622 HasConstCopyConstructor 623 = FieldClassDecl->hasConstCopyConstructor(Context); 624 } 625 } 626 627 // Otherwise, the implicitly declared copy constructor will have 628 // the form 629 // 630 // X::X(X&) 631 QualType ArgType = Context.getTypeDeclType(ClassDecl); 632 if (HasConstCopyConstructor) 633 ArgType = ArgType.withConst(); 634 ArgType = Context.getReferenceType(ArgType); 635 636 // An implicitly-declared copy constructor is an inline public 637 // member of its class. 638 CXXConstructorDecl *CopyConstructor 639 = CXXConstructorDecl::Create(Context, ClassDecl, 640 ClassDecl->getLocation(), 641 ClassDecl->getIdentifier(), 642 Context.getFunctionType(Context.VoidTy, 643 &ArgType, 1, 644 false, 0), 645 /*isExplicit=*/false, 646 /*isInline=*/true, 647 /*isImplicitlyDeclared=*/true); 648 CopyConstructor->setAccess(AS_public); 649 650 // Add the parameter to the constructor. 651 ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor, 652 ClassDecl->getLocation(), 653 /*IdentifierInfo=*/0, 654 ArgType, VarDecl::None, 0, 0); 655 CopyConstructor->setParams(&FromParam, 1); 656 657 ClassDecl->addConstructor(Context, CopyConstructor); 658 } 659 660 // FIXME: Implicit destructor 661 // FIXME: Implicit copy assignment operator 662} 663 664void Sema::ActOnFinishCXXClassDef(DeclTy *D) { 665 CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 666 FieldCollector->FinishClass(); 667 AddImplicitlyDeclaredMembersToClass(Rec); 668 PopDeclContext(); 669 670 // Everything, including inline method definitions, have been parsed. 671 // Let the consumer know of the new TagDecl definition. 672 Consumer.HandleTagDeclDefinition(Rec); 673} 674 675/// ActOnConstructorDeclarator - Called by ActOnDeclarator to complete 676/// the declaration of the given C++ constructor ConDecl that was 677/// built from declarator D. This routine is responsible for checking 678/// that the newly-created constructor declaration is well-formed and 679/// for recording it in the C++ class. Example: 680/// 681/// @code 682/// class X { 683/// X(); // X::X() will be the ConDecl. 684/// }; 685/// @endcode 686Sema::DeclTy *Sema::ActOnConstructorDeclarator(CXXConstructorDecl *ConDecl) { 687 assert(ConDecl && "Expected to receive a constructor declaration"); 688 689 // Check default arguments on the constructor 690 CheckCXXDefaultArguments(ConDecl); 691 692 CXXRecordDecl *ClassDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext); 693 if (!ClassDecl) { 694 ConDecl->setInvalidDecl(); 695 return ConDecl; 696 } 697 698 // Make sure this constructor is an overload of the existing 699 // constructors. 700 OverloadedFunctionDecl::function_iterator MatchedDecl; 701 if (!IsOverload(ConDecl, ClassDecl->getConstructors(), MatchedDecl)) { 702 Diag(ConDecl->getLocation(), 703 diag::err_constructor_redeclared, 704 SourceRange(ConDecl->getLocation())); 705 Diag((*MatchedDecl)->getLocation(), 706 diag::err_previous_declaration, 707 SourceRange((*MatchedDecl)->getLocation())); 708 ConDecl->setInvalidDecl(); 709 return ConDecl; 710 } 711 712 713 // C++ [class.copy]p3: 714 // A declaration of a constructor for a class X is ill-formed if 715 // its first parameter is of type (optionally cv-qualified) X and 716 // either there are no other parameters or else all other 717 // parameters have default arguments. 718 if ((ConDecl->getNumParams() == 1) || 719 (ConDecl->getNumParams() > 1 && 720 ConDecl->getParamDecl(1)->getDefaultArg() != 0)) { 721 QualType ParamType = ConDecl->getParamDecl(0)->getType(); 722 QualType ClassTy = Context.getTagDeclType( 723 const_cast<CXXRecordDecl*>(ConDecl->getParent())); 724 if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) { 725 Diag(ConDecl->getLocation(), 726 diag::err_constructor_byvalue_arg, 727 SourceRange(ConDecl->getParamDecl(0)->getLocation())); 728 ConDecl->setInvalidDecl(); 729 return 0; 730 } 731 } 732 733 // Add this constructor to the set of constructors of the current 734 // class. 735 ClassDecl->addConstructor(Context, ConDecl); 736 737 return (DeclTy *)ConDecl; 738} 739 740//===----------------------------------------------------------------------===// 741// Namespace Handling 742//===----------------------------------------------------------------------===// 743 744/// ActOnStartNamespaceDef - This is called at the start of a namespace 745/// definition. 746Sema::DeclTy *Sema::ActOnStartNamespaceDef(Scope *NamespcScope, 747 SourceLocation IdentLoc, 748 IdentifierInfo *II, 749 SourceLocation LBrace) { 750 NamespaceDecl *Namespc = 751 NamespaceDecl::Create(Context, CurContext, IdentLoc, II); 752 Namespc->setLBracLoc(LBrace); 753 754 Scope *DeclRegionScope = NamespcScope->getParent(); 755 756 if (II) { 757 // C++ [namespace.def]p2: 758 // The identifier in an original-namespace-definition shall not have been 759 // previously defined in the declarative region in which the 760 // original-namespace-definition appears. The identifier in an 761 // original-namespace-definition is the name of the namespace. Subsequently 762 // in that declarative region, it is treated as an original-namespace-name. 763 764 Decl *PrevDecl = 765 LookupDecl(II, Decl::IDNS_Tag | Decl::IDNS_Ordinary, DeclRegionScope, 766 /*enableLazyBuiltinCreation=*/false); 767 768 if (PrevDecl && isDeclInScope(PrevDecl, CurContext, DeclRegionScope)) { 769 if (NamespaceDecl *OrigNS = dyn_cast<NamespaceDecl>(PrevDecl)) { 770 // This is an extended namespace definition. 771 // Attach this namespace decl to the chain of extended namespace 772 // definitions. 773 NamespaceDecl *NextNS = OrigNS; 774 while (NextNS->getNextNamespace()) 775 NextNS = NextNS->getNextNamespace(); 776 777 NextNS->setNextNamespace(Namespc); 778 Namespc->setOriginalNamespace(OrigNS); 779 780 // We won't add this decl to the current scope. We want the namespace 781 // name to return the original namespace decl during a name lookup. 782 } else { 783 // This is an invalid name redefinition. 784 Diag(Namespc->getLocation(), diag::err_redefinition_different_kind, 785 Namespc->getName()); 786 Diag(PrevDecl->getLocation(), diag::err_previous_definition); 787 Namespc->setInvalidDecl(); 788 // Continue on to push Namespc as current DeclContext and return it. 789 } 790 } else { 791 // This namespace name is declared for the first time. 792 PushOnScopeChains(Namespc, DeclRegionScope); 793 } 794 } 795 else { 796 // FIXME: Handle anonymous namespaces 797 } 798 799 // Although we could have an invalid decl (i.e. the namespace name is a 800 // redefinition), push it as current DeclContext and try to continue parsing. 801 PushDeclContext(Namespc->getOriginalNamespace()); 802 return Namespc; 803} 804 805/// ActOnFinishNamespaceDef - This callback is called after a namespace is 806/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef. 807void Sema::ActOnFinishNamespaceDef(DeclTy *D, SourceLocation RBrace) { 808 Decl *Dcl = static_cast<Decl *>(D); 809 NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl); 810 assert(Namespc && "Invalid parameter, expected NamespaceDecl"); 811 Namespc->setRBracLoc(RBrace); 812 PopDeclContext(); 813} 814 815 816/// AddCXXDirectInitializerToDecl - This action is called immediately after 817/// ActOnDeclarator, when a C++ direct initializer is present. 818/// e.g: "int x(1);" 819void Sema::AddCXXDirectInitializerToDecl(DeclTy *Dcl, SourceLocation LParenLoc, 820 ExprTy **ExprTys, unsigned NumExprs, 821 SourceLocation *CommaLocs, 822 SourceLocation RParenLoc) { 823 assert(NumExprs != 0 && ExprTys && "missing expressions"); 824 Decl *RealDecl = static_cast<Decl *>(Dcl); 825 826 // If there is no declaration, there was an error parsing it. Just ignore 827 // the initializer. 828 if (RealDecl == 0) { 829 for (unsigned i = 0; i != NumExprs; ++i) 830 delete static_cast<Expr *>(ExprTys[i]); 831 return; 832 } 833 834 VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl); 835 if (!VDecl) { 836 Diag(RealDecl->getLocation(), diag::err_illegal_initializer); 837 RealDecl->setInvalidDecl(); 838 return; 839 } 840 841 // We will treat direct-initialization as a copy-initialization: 842 // int x(1); -as-> int x = 1; 843 // ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c); 844 // 845 // Clients that want to distinguish between the two forms, can check for 846 // direct initializer using VarDecl::hasCXXDirectInitializer(). 847 // A major benefit is that clients that don't particularly care about which 848 // exactly form was it (like the CodeGen) can handle both cases without 849 // special case code. 850 851 // C++ 8.5p11: 852 // The form of initialization (using parentheses or '=') is generally 853 // insignificant, but does matter when the entity being initialized has a 854 // class type. 855 QualType DeclInitType = VDecl->getType(); 856 if (const ArrayType *Array = Context.getAsArrayType(DeclInitType)) 857 DeclInitType = Array->getElementType(); 858 859 if (VDecl->getType()->isRecordType()) { 860 CXXConstructorDecl *Constructor 861 = PerformDirectInitForClassType(DeclInitType, (Expr **)ExprTys, NumExprs, 862 VDecl->getLocation(), 863 SourceRange(VDecl->getLocation(), 864 RParenLoc), 865 VDecl->getName(), 866 /*HasInitializer=*/true); 867 if (!Constructor) { 868 RealDecl->setInvalidDecl(); 869 } 870 return; 871 } 872 873 if (NumExprs > 1) { 874 Diag(CommaLocs[0], diag::err_builtin_direct_init_more_than_one_arg, 875 SourceRange(VDecl->getLocation(), RParenLoc)); 876 RealDecl->setInvalidDecl(); 877 return; 878 } 879 880 // Let clients know that initialization was done with a direct initializer. 881 VDecl->setCXXDirectInitializer(true); 882 883 assert(NumExprs == 1 && "Expected 1 expression"); 884 // Set the init expression, handles conversions. 885 AddInitializerToDecl(Dcl, ExprTys[0]); 886} 887 888/// PerformDirectInitForClassType - Perform direct-initialization (C++ 889/// [dcl.init]) for a value of the given class type with the given set 890/// of arguments (@p Args). @p Loc is the location in the source code 891/// where the initializer occurs (e.g., a declaration, member 892/// initializer, functional cast, etc.) while @p Range covers the 893/// whole initialization. @p HasInitializer is true if the initializer 894/// was actually written in the source code. When successful, returns 895/// the constructor that will be used to perform the initialization; 896/// when the initialization fails, emits a diagnostic and returns null. 897CXXConstructorDecl * 898Sema::PerformDirectInitForClassType(QualType ClassType, 899 Expr **Args, unsigned NumArgs, 900 SourceLocation Loc, SourceRange Range, 901 std::string InitEntity, 902 bool HasInitializer) { 903 const RecordType *ClassRec = ClassType->getAsRecordType(); 904 assert(ClassRec && "Can only initialize a class type here"); 905 906 // C++ [dcl.init]p14: 907 // 908 // If the initialization is direct-initialization, or if it is 909 // copy-initialization where the cv-unqualified version of the 910 // source type is the same class as, or a derived class of, the 911 // class of the destination, constructors are considered. The 912 // applicable constructors are enumerated (13.3.1.3), and the 913 // best one is chosen through overload resolution (13.3). The 914 // constructor so selected is called to initialize the object, 915 // with the initializer expression(s) as its argument(s). If no 916 // constructor applies, or the overload resolution is ambiguous, 917 // the initialization is ill-formed. 918 // 919 // FIXME: We don't check cv-qualifiers on the class type, because we 920 // don't yet keep track of whether a class type is a POD class type 921 // (or a "trivial" class type, as is used in C++0x). 922 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassRec->getDecl()); 923 OverloadCandidateSet CandidateSet; 924 OverloadCandidateSet::iterator Best; 925 AddOverloadCandidates(ClassDecl->getConstructors(), Args, NumArgs, 926 CandidateSet); 927 switch (BestViableFunction(CandidateSet, Best)) { 928 case OR_Success: 929 // We found a constructor. Return it. 930 return cast<CXXConstructorDecl>(Best->Function); 931 932 case OR_No_Viable_Function: 933 if (CandidateSet.empty()) 934 Diag(Loc, diag::err_ovl_no_viable_function_in_init, 935 InitEntity, Range); 936 else { 937 Diag(Loc, diag::err_ovl_no_viable_function_in_init_with_cands, 938 InitEntity, Range); 939 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 940 } 941 return 0; 942 943 case OR_Ambiguous: 944 Diag(Loc, diag::err_ovl_ambiguous_init, 945 InitEntity, Range); 946 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 947 return 0; 948 } 949 950 return 0; 951} 952 953/// CompareReferenceRelationship - Compare the two types T1 and T2 to 954/// determine whether they are reference-related, 955/// reference-compatible, reference-compatible with added 956/// qualification, or incompatible, for use in C++ initialization by 957/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 958/// type, and the first type (T1) is the pointee type of the reference 959/// type being initialized. 960Sema::ReferenceCompareResult 961Sema::CompareReferenceRelationship(QualType T1, QualType T2, 962 bool& DerivedToBase) { 963 assert(!T1->isReferenceType() && "T1 must be the pointee type of the reference type"); 964 assert(!T2->isReferenceType() && "T2 cannot be a reference type"); 965 966 T1 = Context.getCanonicalType(T1); 967 T2 = Context.getCanonicalType(T2); 968 QualType UnqualT1 = T1.getUnqualifiedType(); 969 QualType UnqualT2 = T2.getUnqualifiedType(); 970 971 // C++ [dcl.init.ref]p4: 972 // Given types “cv1 T1” and “cv2 T2,” “cv1 T1” is 973 // reference-related to “cv2 T2” if T1 is the same type as T2, or 974 // T1 is a base class of T2. 975 if (UnqualT1 == UnqualT2) 976 DerivedToBase = false; 977 else if (IsDerivedFrom(UnqualT2, UnqualT1)) 978 DerivedToBase = true; 979 else 980 return Ref_Incompatible; 981 982 // At this point, we know that T1 and T2 are reference-related (at 983 // least). 984 985 // C++ [dcl.init.ref]p4: 986 // "cv1 T1” is reference-compatible with “cv2 T2” if T1 is 987 // reference-related to T2 and cv1 is the same cv-qualification 988 // as, or greater cv-qualification than, cv2. For purposes of 989 // overload resolution, cases for which cv1 is greater 990 // cv-qualification than cv2 are identified as 991 // reference-compatible with added qualification (see 13.3.3.2). 992 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 993 return Ref_Compatible; 994 else if (T1.isMoreQualifiedThan(T2)) 995 return Ref_Compatible_With_Added_Qualification; 996 else 997 return Ref_Related; 998} 999 1000/// CheckReferenceInit - Check the initialization of a reference 1001/// variable with the given initializer (C++ [dcl.init.ref]). Init is 1002/// the initializer (either a simple initializer or an initializer 1003/// list), and DeclType is the type of the declaration. When ICS is 1004/// non-null, this routine will compute the implicit conversion 1005/// sequence according to C++ [over.ics.ref] and will not produce any 1006/// diagnostics; when ICS is null, it will emit diagnostics when any 1007/// errors are found. Either way, a return value of true indicates 1008/// that there was a failure, a return value of false indicates that 1009/// the reference initialization succeeded. 1010/// 1011/// When @p SuppressUserConversions, user-defined conversions are 1012/// suppressed. 1013bool 1014Sema::CheckReferenceInit(Expr *&Init, QualType &DeclType, 1015 ImplicitConversionSequence *ICS, 1016 bool SuppressUserConversions) { 1017 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 1018 1019 QualType T1 = DeclType->getAsReferenceType()->getPointeeType(); 1020 QualType T2 = Init->getType(); 1021 1022 // Compute some basic properties of the types and the initializer. 1023 bool DerivedToBase = false; 1024 Expr::isLvalueResult InitLvalue = Init->isLvalue(Context); 1025 ReferenceCompareResult RefRelationship 1026 = CompareReferenceRelationship(T1, T2, DerivedToBase); 1027 1028 // Most paths end in a failed conversion. 1029 if (ICS) 1030 ICS->ConversionKind = ImplicitConversionSequence::BadConversion; 1031 1032 // C++ [dcl.init.ref]p5: 1033 // A reference to type “cv1 T1” is initialized by an expression 1034 // of type “cv2 T2” as follows: 1035 1036 // -- If the initializer expression 1037 1038 bool BindsDirectly = false; 1039 // -- is an lvalue (but is not a bit-field), and “cv1 T1” is 1040 // reference-compatible with “cv2 T2,” or 1041 // 1042 // Note that the bit-field check is skipped if we are just computing 1043 // the implicit conversion sequence (C++ [over.best.ics]p2). 1044 if (InitLvalue == Expr::LV_Valid && (ICS || !Init->isBitField()) && 1045 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1046 BindsDirectly = true; 1047 1048 if (ICS) { 1049 // C++ [over.ics.ref]p1: 1050 // When a parameter of reference type binds directly (8.5.3) 1051 // to an argument expression, the implicit conversion sequence 1052 // is the identity conversion, unless the argument expression 1053 // has a type that is a derived class of the parameter type, 1054 // in which case the implicit conversion sequence is a 1055 // derived-to-base Conversion (13.3.3.1). 1056 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1057 ICS->Standard.First = ICK_Identity; 1058 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1059 ICS->Standard.Third = ICK_Identity; 1060 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1061 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1062 ICS->Standard.ReferenceBinding = true; 1063 ICS->Standard.DirectBinding = true; 1064 1065 // Nothing more to do: the inaccessibility/ambiguity check for 1066 // derived-to-base conversions is suppressed when we're 1067 // computing the implicit conversion sequence (C++ 1068 // [over.best.ics]p2). 1069 return false; 1070 } else { 1071 // Perform the conversion. 1072 // FIXME: Binding to a subobject of the lvalue is going to require 1073 // more AST annotation than this. 1074 ImpCastExprToType(Init, T1); 1075 } 1076 } 1077 1078 // -- has a class type (i.e., T2 is a class type) and can be 1079 // implicitly converted to an lvalue of type “cv3 T3,” 1080 // where “cv1 T1” is reference-compatible with “cv3 T3” 1081 // 92) (this conversion is selected by enumerating the 1082 // applicable conversion functions (13.3.1.6) and choosing 1083 // the best one through overload resolution (13.3)), 1084 // FIXME: Implement this second bullet, once we have conversion 1085 // functions. Also remember C++ [over.ics.ref]p1, second part. 1086 1087 if (BindsDirectly) { 1088 // C++ [dcl.init.ref]p4: 1089 // [...] In all cases where the reference-related or 1090 // reference-compatible relationship of two types is used to 1091 // establish the validity of a reference binding, and T1 is a 1092 // base class of T2, a program that necessitates such a binding 1093 // is ill-formed if T1 is an inaccessible (clause 11) or 1094 // ambiguous (10.2) base class of T2. 1095 // 1096 // Note that we only check this condition when we're allowed to 1097 // complain about errors, because we should not be checking for 1098 // ambiguity (or inaccessibility) unless the reference binding 1099 // actually happens. 1100 if (DerivedToBase) 1101 return CheckDerivedToBaseConversion(T2, T1, 1102 Init->getSourceRange().getBegin(), 1103 Init->getSourceRange()); 1104 else 1105 return false; 1106 } 1107 1108 // -- Otherwise, the reference shall be to a non-volatile const 1109 // type (i.e., cv1 shall be const). 1110 if (T1.getCVRQualifiers() != QualType::Const) { 1111 if (!ICS) 1112 Diag(Init->getSourceRange().getBegin(), 1113 diag::err_not_reference_to_const_init, 1114 T1.getAsString(), 1115 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1116 T2.getAsString(), Init->getSourceRange()); 1117 return true; 1118 } 1119 1120 // -- If the initializer expression is an rvalue, with T2 a 1121 // class type, and “cv1 T1” is reference-compatible with 1122 // “cv2 T2,” the reference is bound in one of the 1123 // following ways (the choice is implementation-defined): 1124 // 1125 // -- The reference is bound to the object represented by 1126 // the rvalue (see 3.10) or to a sub-object within that 1127 // object. 1128 // 1129 // -- A temporary of type “cv1 T2” [sic] is created, and 1130 // a constructor is called to copy the entire rvalue 1131 // object into the temporary. The reference is bound to 1132 // the temporary or to a sub-object within the 1133 // temporary. 1134 // 1135 // 1136 // The constructor that would be used to make the copy 1137 // shall be callable whether or not the copy is actually 1138 // done. 1139 // 1140 // Note that C++0x [dcl.ref.init]p5 takes away this implementation 1141 // freedom, so we will always take the first option and never build 1142 // a temporary in this case. FIXME: We will, however, have to check 1143 // for the presence of a copy constructor in C++98/03 mode. 1144 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 1145 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1146 if (ICS) { 1147 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1148 ICS->Standard.First = ICK_Identity; 1149 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1150 ICS->Standard.Third = ICK_Identity; 1151 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1152 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1153 ICS->Standard.ReferenceBinding = true; 1154 ICS->Standard.DirectBinding = false; 1155 } else { 1156 // FIXME: Binding to a subobject of the rvalue is going to require 1157 // more AST annotation than this. 1158 ImpCastExprToType(Init, T1); 1159 } 1160 return false; 1161 } 1162 1163 // -- Otherwise, a temporary of type “cv1 T1” is created and 1164 // initialized from the initializer expression using the 1165 // rules for a non-reference copy initialization (8.5). The 1166 // reference is then bound to the temporary. If T1 is 1167 // reference-related to T2, cv1 must be the same 1168 // cv-qualification as, or greater cv-qualification than, 1169 // cv2; otherwise, the program is ill-formed. 1170 if (RefRelationship == Ref_Related) { 1171 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 1172 // we would be reference-compatible or reference-compatible with 1173 // added qualification. But that wasn't the case, so the reference 1174 // initialization fails. 1175 if (!ICS) 1176 Diag(Init->getSourceRange().getBegin(), 1177 diag::err_reference_init_drops_quals, 1178 T1.getAsString(), 1179 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1180 T2.getAsString(), Init->getSourceRange()); 1181 return true; 1182 } 1183 1184 // Actually try to convert the initializer to T1. 1185 if (ICS) { 1186 /// C++ [over.ics.ref]p2: 1187 /// 1188 /// When a parameter of reference type is not bound directly to 1189 /// an argument expression, the conversion sequence is the one 1190 /// required to convert the argument expression to the 1191 /// underlying type of the reference according to 1192 /// 13.3.3.1. Conceptually, this conversion sequence corresponds 1193 /// to copy-initializing a temporary of the underlying type with 1194 /// the argument expression. Any difference in top-level 1195 /// cv-qualification is subsumed by the initialization itself 1196 /// and does not constitute a conversion. 1197 *ICS = TryImplicitConversion(Init, T1, SuppressUserConversions); 1198 return ICS->ConversionKind == ImplicitConversionSequence::BadConversion; 1199 } else { 1200 return PerformImplicitConversion(Init, T1); 1201 } 1202} 1203