SemaDeclCXX.cpp revision 3996f23ac20de411e0b5931a451bd05142f0b712
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 // 130 // FIXME: CheckSingleAssignmentConstraints has the wrong semantics 131 // for C++ (since we want copy-initialization, not copy-assignment), 132 // but we don't have the right semantics implemented yet. Because of 133 // this, our error message is also very poor. 134 QualType DefaultArgType = DefaultArg->getType(); 135 Expr *DefaultArgPtr = DefaultArg.get(); 136 AssignConvertType ConvTy = CheckSingleAssignmentConstraints(ParamType, 137 DefaultArgPtr); 138 if (DefaultArgPtr != DefaultArg.get()) { 139 DefaultArg.take(); 140 DefaultArg.reset(DefaultArgPtr); 141 } 142 if (DiagnoseAssignmentResult(ConvTy, DefaultArg->getLocStart(), 143 ParamType, DefaultArgType, DefaultArg.get(), 144 "in default argument")) { 145 return; 146 } 147 148 // Check that the default argument is well-formed 149 CheckDefaultArgumentVisitor DefaultArgChecker(DefaultArg.get(), this); 150 if (DefaultArgChecker.Visit(DefaultArg.get())) 151 return; 152 153 // Okay: add the default argument to the parameter 154 Param->setDefaultArg(DefaultArg.take()); 155} 156 157/// CheckExtraCXXDefaultArguments - Check for any extra default 158/// arguments in the declarator, which is not a function declaration 159/// or definition and therefore is not permitted to have default 160/// arguments. This routine should be invoked for every declarator 161/// that is not a function declaration or definition. 162void Sema::CheckExtraCXXDefaultArguments(Declarator &D) { 163 // C++ [dcl.fct.default]p3 164 // A default argument expression shall be specified only in the 165 // parameter-declaration-clause of a function declaration or in a 166 // template-parameter (14.1). It shall not be specified for a 167 // parameter pack. If it is specified in a 168 // parameter-declaration-clause, it shall not occur within a 169 // declarator or abstract-declarator of a parameter-declaration. 170 for (unsigned i = 0; i < D.getNumTypeObjects(); ++i) { 171 DeclaratorChunk &chunk = D.getTypeObject(i); 172 if (chunk.Kind == DeclaratorChunk::Function) { 173 for (unsigned argIdx = 0; argIdx < chunk.Fun.NumArgs; ++argIdx) { 174 ParmVarDecl *Param = (ParmVarDecl *)chunk.Fun.ArgInfo[argIdx].Param; 175 if (Param->getDefaultArg()) { 176 Diag(Param->getLocation(), diag::err_param_default_argument_nonfunc, 177 Param->getDefaultArg()->getSourceRange()); 178 Param->setDefaultArg(0); 179 } 180 } 181 } 182 } 183} 184 185// MergeCXXFunctionDecl - Merge two declarations of the same C++ 186// function, once we already know that they have the same 187// type. Subroutine of MergeFunctionDecl. 188FunctionDecl * 189Sema::MergeCXXFunctionDecl(FunctionDecl *New, FunctionDecl *Old) { 190 // C++ [dcl.fct.default]p4: 191 // 192 // For non-template functions, default arguments can be added in 193 // later declarations of a function in the same 194 // scope. Declarations in different scopes have completely 195 // distinct sets of default arguments. That is, declarations in 196 // inner scopes do not acquire default arguments from 197 // declarations in outer scopes, and vice versa. In a given 198 // function declaration, all parameters subsequent to a 199 // parameter with a default argument shall have default 200 // arguments supplied in this or previous declarations. A 201 // default argument shall not be redefined by a later 202 // declaration (not even to the same value). 203 for (unsigned p = 0, NumParams = Old->getNumParams(); p < NumParams; ++p) { 204 ParmVarDecl *OldParam = Old->getParamDecl(p); 205 ParmVarDecl *NewParam = New->getParamDecl(p); 206 207 if(OldParam->getDefaultArg() && NewParam->getDefaultArg()) { 208 Diag(NewParam->getLocation(), 209 diag::err_param_default_argument_redefinition, 210 NewParam->getDefaultArg()->getSourceRange()); 211 Diag(OldParam->getLocation(), diag::err_previous_definition); 212 } else if (OldParam->getDefaultArg()) { 213 // Merge the old default argument into the new parameter 214 NewParam->setDefaultArg(OldParam->getDefaultArg()); 215 } 216 } 217 218 return New; 219} 220 221/// CheckCXXDefaultArguments - Verify that the default arguments for a 222/// function declaration are well-formed according to C++ 223/// [dcl.fct.default]. 224void Sema::CheckCXXDefaultArguments(FunctionDecl *FD) { 225 unsigned NumParams = FD->getNumParams(); 226 unsigned p; 227 228 // Find first parameter with a default argument 229 for (p = 0; p < NumParams; ++p) { 230 ParmVarDecl *Param = FD->getParamDecl(p); 231 if (Param->getDefaultArg()) 232 break; 233 } 234 235 // C++ [dcl.fct.default]p4: 236 // In a given function declaration, all parameters 237 // subsequent to a parameter with a default argument shall 238 // have default arguments supplied in this or previous 239 // declarations. A default argument shall not be redefined 240 // by a later declaration (not even to the same value). 241 unsigned LastMissingDefaultArg = 0; 242 for(; p < NumParams; ++p) { 243 ParmVarDecl *Param = FD->getParamDecl(p); 244 if (!Param->getDefaultArg()) { 245 if (Param->getIdentifier()) 246 Diag(Param->getLocation(), 247 diag::err_param_default_argument_missing_name, 248 Param->getIdentifier()->getName()); 249 else 250 Diag(Param->getLocation(), 251 diag::err_param_default_argument_missing); 252 253 LastMissingDefaultArg = p; 254 } 255 } 256 257 if (LastMissingDefaultArg > 0) { 258 // Some default arguments were missing. Clear out all of the 259 // default arguments up to (and including) the last missing 260 // default argument, so that we leave the function parameters 261 // in a semantically valid state. 262 for (p = 0; p <= LastMissingDefaultArg; ++p) { 263 ParmVarDecl *Param = FD->getParamDecl(p); 264 if (Param->getDefaultArg()) { 265 delete Param->getDefaultArg(); 266 Param->setDefaultArg(0); 267 } 268 } 269 } 270} 271 272/// isCurrentClassName - Determine whether the identifier II is the 273/// name of the class type currently being defined. In the case of 274/// nested classes, this will only return true if II is the name of 275/// the innermost class. 276bool Sema::isCurrentClassName(const IdentifierInfo &II, Scope *) { 277 if (CXXRecordDecl *CurDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext)) 278 return &II == CurDecl->getIdentifier(); 279 else 280 return false; 281} 282 283/// ActOnBaseSpecifier - Parsed a base specifier. A base specifier is 284/// one entry in the base class list of a class specifier, for 285/// example: 286/// class foo : public bar, virtual private baz { 287/// 'public bar' and 'virtual private baz' are each base-specifiers. 288Sema::BaseResult 289Sema::ActOnBaseSpecifier(DeclTy *classdecl, SourceRange SpecifierRange, 290 bool Virtual, AccessSpecifier Access, 291 TypeTy *basetype, SourceLocation BaseLoc) { 292 RecordDecl *Decl = (RecordDecl*)classdecl; 293 QualType BaseType = Context.getTypeDeclType((TypeDecl*)basetype); 294 295 // Base specifiers must be record types. 296 if (!BaseType->isRecordType()) { 297 Diag(BaseLoc, diag::err_base_must_be_class, SpecifierRange); 298 return true; 299 } 300 301 // C++ [class.union]p1: 302 // A union shall not be used as a base class. 303 if (BaseType->isUnionType()) { 304 Diag(BaseLoc, diag::err_union_as_base_class, SpecifierRange); 305 return true; 306 } 307 308 // C++ [class.union]p1: 309 // A union shall not have base classes. 310 if (Decl->isUnion()) { 311 Diag(Decl->getLocation(), diag::err_base_clause_on_union, 312 SpecifierRange); 313 return true; 314 } 315 316 // C++ [class.derived]p2: 317 // The class-name in a base-specifier shall not be an incompletely 318 // defined class. 319 if (BaseType->isIncompleteType()) { 320 Diag(BaseLoc, diag::err_incomplete_base_class, SpecifierRange); 321 return true; 322 } 323 324 // Create the base specifier. 325 return new CXXBaseSpecifier(SpecifierRange, Virtual, 326 BaseType->isClassType(), Access, BaseType); 327} 328 329/// ActOnBaseSpecifiers - Attach the given base specifiers to the 330/// class, after checking whether there are any duplicate base 331/// classes. 332void Sema::ActOnBaseSpecifiers(DeclTy *ClassDecl, BaseTy **Bases, 333 unsigned NumBases) { 334 if (NumBases == 0) 335 return; 336 337 // Used to keep track of which base types we have already seen, so 338 // that we can properly diagnose redundant direct base types. Note 339 // that the key is always the unqualified canonical type of the base 340 // class. 341 std::map<QualType, CXXBaseSpecifier*, QualTypeOrdering> KnownBaseTypes; 342 343 // Copy non-redundant base specifiers into permanent storage. 344 CXXBaseSpecifier **BaseSpecs = (CXXBaseSpecifier **)Bases; 345 unsigned NumGoodBases = 0; 346 for (unsigned idx = 0; idx < NumBases; ++idx) { 347 QualType NewBaseType 348 = Context.getCanonicalType(BaseSpecs[idx]->getType()); 349 NewBaseType = NewBaseType.getUnqualifiedType(); 350 351 if (KnownBaseTypes[NewBaseType]) { 352 // C++ [class.mi]p3: 353 // A class shall not be specified as a direct base class of a 354 // derived class more than once. 355 Diag(BaseSpecs[idx]->getSourceRange().getBegin(), 356 diag::err_duplicate_base_class, 357 KnownBaseTypes[NewBaseType]->getType().getAsString(), 358 BaseSpecs[idx]->getSourceRange()); 359 360 // Delete the duplicate base class specifier; we're going to 361 // overwrite its pointer later. 362 delete BaseSpecs[idx]; 363 } else { 364 // Okay, add this new base class. 365 KnownBaseTypes[NewBaseType] = BaseSpecs[idx]; 366 BaseSpecs[NumGoodBases++] = BaseSpecs[idx]; 367 } 368 } 369 370 // Attach the remaining base class specifiers to the derived class. 371 CXXRecordDecl *Decl = (CXXRecordDecl*)ClassDecl; 372 Decl->setBases(BaseSpecs, NumGoodBases); 373 374 // Delete the remaining (good) base class specifiers, since their 375 // data has been copied into the CXXRecordDecl. 376 for (unsigned idx = 0; idx < NumGoodBases; ++idx) 377 delete BaseSpecs[idx]; 378} 379 380//===----------------------------------------------------------------------===// 381// C++ class member Handling 382//===----------------------------------------------------------------------===// 383 384/// ActOnStartCXXClassDef - This is called at the start of a class/struct/union 385/// definition, when on C++. 386void Sema::ActOnStartCXXClassDef(Scope *S, DeclTy *D, SourceLocation LBrace) { 387 CXXRecordDecl *Dcl = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 388 PushDeclContext(Dcl); 389 FieldCollector->StartClass(); 390 391 if (Dcl->getIdentifier()) { 392 // C++ [class]p2: 393 // [...] The class-name is also inserted into the scope of the 394 // class itself; this is known as the injected-class-name. For 395 // purposes of access checking, the injected-class-name is treated 396 // as if it were a public member name. 397 TypedefDecl *InjectedClassName 398 = TypedefDecl::Create(Context, Dcl, LBrace, Dcl->getIdentifier(), 399 Context.getTypeDeclType(Dcl), /*PrevDecl=*/0); 400 PushOnScopeChains(InjectedClassName, S); 401 } 402} 403 404/// ActOnCXXMemberDeclarator - This is invoked when a C++ class member 405/// declarator is parsed. 'AS' is the access specifier, 'BW' specifies the 406/// bitfield width if there is one and 'InitExpr' specifies the initializer if 407/// any. 'LastInGroup' is non-null for cases where one declspec has multiple 408/// declarators on it. 409/// 410/// NOTE: Because of CXXFieldDecl's inability to be chained like ScopedDecls, if 411/// an instance field is declared, a new CXXFieldDecl is created but the method 412/// does *not* return it; it returns LastInGroup instead. The other C++ members 413/// (which are all ScopedDecls) are returned after appending them to 414/// LastInGroup. 415Sema::DeclTy * 416Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D, 417 ExprTy *BW, ExprTy *InitExpr, 418 DeclTy *LastInGroup) { 419 const DeclSpec &DS = D.getDeclSpec(); 420 IdentifierInfo *II = D.getIdentifier(); 421 Expr *BitWidth = static_cast<Expr*>(BW); 422 Expr *Init = static_cast<Expr*>(InitExpr); 423 SourceLocation Loc = D.getIdentifierLoc(); 424 425 // C++ 9.2p6: A member shall not be declared to have automatic storage 426 // duration (auto, register) or with the extern storage-class-specifier. 427 switch (DS.getStorageClassSpec()) { 428 case DeclSpec::SCS_unspecified: 429 case DeclSpec::SCS_typedef: 430 case DeclSpec::SCS_static: 431 // FALL THROUGH. 432 break; 433 default: 434 if (DS.getStorageClassSpecLoc().isValid()) 435 Diag(DS.getStorageClassSpecLoc(), 436 diag::err_storageclass_invalid_for_member); 437 else 438 Diag(DS.getThreadSpecLoc(), diag::err_storageclass_invalid_for_member); 439 D.getMutableDeclSpec().ClearStorageClassSpecs(); 440 } 441 442 bool isFunc = D.isFunctionDeclarator(); 443 if (!isFunc && 444 D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_typedef && 445 D.getNumTypeObjects() == 0) { 446 // Check also for this case: 447 // 448 // typedef int f(); 449 // f a; 450 // 451 Decl *TD = static_cast<Decl *>(DS.getTypeRep()); 452 isFunc = Context.getTypeDeclType(cast<TypeDecl>(TD))->isFunctionType(); 453 } 454 455 bool isInstField = (DS.getStorageClassSpec() == DeclSpec::SCS_unspecified && 456 !isFunc); 457 458 Decl *Member; 459 bool InvalidDecl = false; 460 461 if (isInstField) 462 Member = static_cast<Decl*>(ActOnField(S, Loc, D, BitWidth)); 463 else 464 Member = static_cast<Decl*>(ActOnDeclarator(S, D, LastInGroup)); 465 466 if (!Member) return LastInGroup; 467 468 assert((II || isInstField) && "No identifier for non-field ?"); 469 470 // set/getAccess is not part of Decl's interface to avoid bloating it with C++ 471 // specific methods. Use a wrapper class that can be used with all C++ class 472 // member decls. 473 CXXClassMemberWrapper(Member).setAccess(AS); 474 475 if (BitWidth) { 476 // C++ 9.6p2: Only when declaring an unnamed bit-field may the 477 // constant-expression be a value equal to zero. 478 // FIXME: Check this. 479 480 if (D.isFunctionDeclarator()) { 481 // FIXME: Emit diagnostic about only constructors taking base initializers 482 // or something similar, when constructor support is in place. 483 Diag(Loc, diag::err_not_bitfield_type, 484 II->getName(), BitWidth->getSourceRange()); 485 InvalidDecl = true; 486 487 } else if (isInstField) { 488 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 489 if (!cast<FieldDecl>(Member)->getType()->isIntegralType()) { 490 Diag(Loc, diag::err_not_integral_type_bitfield, 491 II->getName(), BitWidth->getSourceRange()); 492 InvalidDecl = true; 493 } 494 495 } else if (isa<FunctionDecl>(Member)) { 496 // A function typedef ("typedef int f(); f a;"). 497 // C++ 9.6p3: A bit-field shall have integral or enumeration type. 498 Diag(Loc, diag::err_not_integral_type_bitfield, 499 II->getName(), BitWidth->getSourceRange()); 500 InvalidDecl = true; 501 502 } else if (isa<TypedefDecl>(Member)) { 503 // "cannot declare 'A' to be a bit-field type" 504 Diag(Loc, diag::err_not_bitfield_type, II->getName(), 505 BitWidth->getSourceRange()); 506 InvalidDecl = true; 507 508 } else { 509 assert(isa<CXXClassVarDecl>(Member) && 510 "Didn't we cover all member kinds?"); 511 // C++ 9.6p3: A bit-field shall not be a static member. 512 // "static member 'A' cannot be a bit-field" 513 Diag(Loc, diag::err_static_not_bitfield, II->getName(), 514 BitWidth->getSourceRange()); 515 InvalidDecl = true; 516 } 517 } 518 519 if (Init) { 520 // C++ 9.2p4: A member-declarator can contain a constant-initializer only 521 // if it declares a static member of const integral or const enumeration 522 // type. 523 if (CXXClassVarDecl *CVD = dyn_cast<CXXClassVarDecl>(Member)) { 524 // ...static member of... 525 CVD->setInit(Init); 526 // ...const integral or const enumeration type. 527 if (Context.getCanonicalType(CVD->getType()).isConstQualified() && 528 CVD->getType()->isIntegralType()) { 529 // constant-initializer 530 if (CheckForConstantInitializer(Init, CVD->getType())) 531 InvalidDecl = true; 532 533 } else { 534 // not const integral. 535 Diag(Loc, diag::err_member_initialization, 536 II->getName(), Init->getSourceRange()); 537 InvalidDecl = true; 538 } 539 540 } else { 541 // not static member. 542 Diag(Loc, diag::err_member_initialization, 543 II->getName(), Init->getSourceRange()); 544 InvalidDecl = true; 545 } 546 } 547 548 if (InvalidDecl) 549 Member->setInvalidDecl(); 550 551 if (isInstField) { 552 FieldCollector->Add(cast<CXXFieldDecl>(Member)); 553 return LastInGroup; 554 } 555 return Member; 556} 557 558void Sema::ActOnFinishCXXMemberSpecification(Scope* S, SourceLocation RLoc, 559 DeclTy *TagDecl, 560 SourceLocation LBrac, 561 SourceLocation RBrac) { 562 ActOnFields(S, RLoc, TagDecl, 563 (DeclTy**)FieldCollector->getCurFields(), 564 FieldCollector->getCurNumFields(), LBrac, RBrac, 0); 565} 566 567/// AddImplicitlyDeclaredMembersToClass - Adds any implicitly-declared 568/// special functions, such as the default constructor, copy 569/// constructor, or destructor, to the given C++ class (C++ 570/// [special]p1). This routine can only be executed just before the 571/// definition of the class is complete. 572void Sema::AddImplicitlyDeclaredMembersToClass(CXXRecordDecl *ClassDecl) { 573 if (!ClassDecl->hasUserDeclaredConstructor()) { 574 // C++ [class.ctor]p5: 575 // A default constructor for a class X is a constructor of class X 576 // that can be called without an argument. If there is no 577 // user-declared constructor for class X, a default constructor is 578 // implicitly declared. An implicitly-declared default constructor 579 // is an inline public member of its class. 580 CXXConstructorDecl *DefaultCon = 581 CXXConstructorDecl::Create(Context, ClassDecl, 582 ClassDecl->getLocation(), 583 ClassDecl->getIdentifier(), 584 Context.getFunctionType(Context.VoidTy, 585 0, 0, false, 0), 586 /*isExplicit=*/false, 587 /*isInline=*/true, 588 /*isImplicitlyDeclared=*/true); 589 DefaultCon->setAccess(AS_public); 590 ClassDecl->addConstructor(Context, DefaultCon); 591 } 592 593 if (!ClassDecl->hasUserDeclaredCopyConstructor()) { 594 // C++ [class.copy]p4: 595 // If the class definition does not explicitly declare a copy 596 // constructor, one is declared implicitly. 597 598 // C++ [class.copy]p5: 599 // The implicitly-declared copy constructor for a class X will 600 // have the form 601 // 602 // X::X(const X&) 603 // 604 // if 605 bool HasConstCopyConstructor = true; 606 607 // -- each direct or virtual base class B of X has a copy 608 // constructor whose first parameter is of type const B& or 609 // const volatile B&, and 610 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 611 HasConstCopyConstructor && Base != ClassDecl->bases_end(); ++Base) { 612 const CXXRecordDecl *BaseClassDecl 613 = cast<CXXRecordDecl>(Base->getType()->getAsRecordType()->getDecl()); 614 HasConstCopyConstructor 615 = BaseClassDecl->hasConstCopyConstructor(Context); 616 } 617 618 // -- for all the nonstatic data members of X that are of a 619 // class type M (or array thereof), each such class type 620 // has a copy constructor whose first parameter is of type 621 // const M& or const volatile M&. 622 for (CXXRecordDecl::field_iterator Field = ClassDecl->field_begin(); 623 HasConstCopyConstructor && Field != ClassDecl->field_end(); ++Field) { 624 QualType FieldType = (*Field)->getType(); 625 if (const ArrayType *Array = Context.getAsArrayType(FieldType)) 626 FieldType = Array->getElementType(); 627 if (const RecordType *FieldClassType = FieldType->getAsRecordType()) { 628 const CXXRecordDecl *FieldClassDecl 629 = cast<CXXRecordDecl>(FieldClassType->getDecl()); 630 HasConstCopyConstructor 631 = FieldClassDecl->hasConstCopyConstructor(Context); 632 } 633 } 634 635 // Otherwise, the implicitly declared copy constructor will have 636 // the form 637 // 638 // X::X(X&) 639 QualType ArgType = Context.getTypeDeclType(ClassDecl); 640 if (HasConstCopyConstructor) 641 ArgType = ArgType.withConst(); 642 ArgType = Context.getReferenceType(ArgType); 643 644 // An implicitly-declared copy constructor is an inline public 645 // member of its class. 646 CXXConstructorDecl *CopyConstructor 647 = CXXConstructorDecl::Create(Context, ClassDecl, 648 ClassDecl->getLocation(), 649 ClassDecl->getIdentifier(), 650 Context.getFunctionType(Context.VoidTy, 651 &ArgType, 1, 652 false, 0), 653 /*isExplicit=*/false, 654 /*isInline=*/true, 655 /*isImplicitlyDeclared=*/true); 656 CopyConstructor->setAccess(AS_public); 657 658 // Add the parameter to the constructor. 659 ParmVarDecl *FromParam = ParmVarDecl::Create(Context, CopyConstructor, 660 ClassDecl->getLocation(), 661 /*IdentifierInfo=*/0, 662 ArgType, VarDecl::None, 0, 0); 663 CopyConstructor->setParams(&FromParam, 1); 664 665 ClassDecl->addConstructor(Context, CopyConstructor); 666 } 667 668 // FIXME: Implicit destructor 669 // FIXME: Implicit copy assignment operator 670} 671 672void Sema::ActOnFinishCXXClassDef(DeclTy *D) { 673 CXXRecordDecl *Rec = cast<CXXRecordDecl>(static_cast<Decl *>(D)); 674 FieldCollector->FinishClass(); 675 AddImplicitlyDeclaredMembersToClass(Rec); 676 PopDeclContext(); 677 678 // Everything, including inline method definitions, have been parsed. 679 // Let the consumer know of the new TagDecl definition. 680 Consumer.HandleTagDeclDefinition(Rec); 681} 682 683/// ActOnConstructorDeclarator - Called by ActOnDeclarator to complete 684/// the declaration of the given C++ constructor ConDecl that was 685/// built from declarator D. This routine is responsible for checking 686/// that the newly-created constructor declaration is well-formed and 687/// for recording it in the C++ class. Example: 688/// 689/// @code 690/// class X { 691/// X(); // X::X() will be the ConDecl. 692/// }; 693/// @endcode 694Sema::DeclTy *Sema::ActOnConstructorDeclarator(CXXConstructorDecl *ConDecl) { 695 assert(ConDecl && "Expected to receive a constructor declaration"); 696 697 // Check default arguments on the constructor 698 CheckCXXDefaultArguments(ConDecl); 699 700 CXXRecordDecl *ClassDecl = dyn_cast_or_null<CXXRecordDecl>(CurContext); 701 if (!ClassDecl) { 702 ConDecl->setInvalidDecl(); 703 return ConDecl; 704 } 705 706 // Make sure this constructor is an overload of the existing 707 // constructors. 708 OverloadedFunctionDecl::function_iterator MatchedDecl; 709 if (!IsOverload(ConDecl, ClassDecl->getConstructors(), MatchedDecl)) { 710 Diag(ConDecl->getLocation(), 711 diag::err_constructor_redeclared, 712 SourceRange(ConDecl->getLocation())); 713 Diag((*MatchedDecl)->getLocation(), 714 diag::err_previous_declaration, 715 SourceRange((*MatchedDecl)->getLocation())); 716 ConDecl->setInvalidDecl(); 717 return ConDecl; 718 } 719 720 721 // C++ [class.copy]p3: 722 // A declaration of a constructor for a class X is ill-formed if 723 // its first parameter is of type (optionally cv-qualified) X and 724 // either there are no other parameters or else all other 725 // parameters have default arguments. 726 if ((ConDecl->getNumParams() == 1) || 727 (ConDecl->getNumParams() > 1 && 728 ConDecl->getParamDecl(1)->getDefaultArg() != 0)) { 729 QualType ParamType = ConDecl->getParamDecl(0)->getType(); 730 QualType ClassTy = Context.getTagDeclType( 731 const_cast<CXXRecordDecl*>(ConDecl->getParent())); 732 if (Context.getCanonicalType(ParamType).getUnqualifiedType() == ClassTy) { 733 Diag(ConDecl->getLocation(), 734 diag::err_constructor_byvalue_arg, 735 SourceRange(ConDecl->getParamDecl(0)->getLocation())); 736 ConDecl->setInvalidDecl(); 737 return 0; 738 } 739 } 740 741 // Add this constructor to the set of constructors of the current 742 // class. 743 ClassDecl->addConstructor(Context, ConDecl); 744 745 return (DeclTy *)ConDecl; 746} 747 748//===----------------------------------------------------------------------===// 749// Namespace Handling 750//===----------------------------------------------------------------------===// 751 752/// ActOnStartNamespaceDef - This is called at the start of a namespace 753/// definition. 754Sema::DeclTy *Sema::ActOnStartNamespaceDef(Scope *NamespcScope, 755 SourceLocation IdentLoc, 756 IdentifierInfo *II, 757 SourceLocation LBrace) { 758 NamespaceDecl *Namespc = 759 NamespaceDecl::Create(Context, CurContext, IdentLoc, II); 760 Namespc->setLBracLoc(LBrace); 761 762 Scope *DeclRegionScope = NamespcScope->getParent(); 763 764 if (II) { 765 // C++ [namespace.def]p2: 766 // The identifier in an original-namespace-definition shall not have been 767 // previously defined in the declarative region in which the 768 // original-namespace-definition appears. The identifier in an 769 // original-namespace-definition is the name of the namespace. Subsequently 770 // in that declarative region, it is treated as an original-namespace-name. 771 772 Decl *PrevDecl = 773 LookupDecl(II, Decl::IDNS_Tag | Decl::IDNS_Ordinary, DeclRegionScope, 774 /*enableLazyBuiltinCreation=*/false); 775 776 if (PrevDecl && isDeclInScope(PrevDecl, CurContext, DeclRegionScope)) { 777 if (NamespaceDecl *OrigNS = dyn_cast<NamespaceDecl>(PrevDecl)) { 778 // This is an extended namespace definition. 779 // Attach this namespace decl to the chain of extended namespace 780 // definitions. 781 NamespaceDecl *NextNS = OrigNS; 782 while (NextNS->getNextNamespace()) 783 NextNS = NextNS->getNextNamespace(); 784 785 NextNS->setNextNamespace(Namespc); 786 Namespc->setOriginalNamespace(OrigNS); 787 788 // We won't add this decl to the current scope. We want the namespace 789 // name to return the original namespace decl during a name lookup. 790 } else { 791 // This is an invalid name redefinition. 792 Diag(Namespc->getLocation(), diag::err_redefinition_different_kind, 793 Namespc->getName()); 794 Diag(PrevDecl->getLocation(), diag::err_previous_definition); 795 Namespc->setInvalidDecl(); 796 // Continue on to push Namespc as current DeclContext and return it. 797 } 798 } else { 799 // This namespace name is declared for the first time. 800 PushOnScopeChains(Namespc, DeclRegionScope); 801 } 802 } 803 else { 804 // FIXME: Handle anonymous namespaces 805 } 806 807 // Although we could have an invalid decl (i.e. the namespace name is a 808 // redefinition), push it as current DeclContext and try to continue parsing. 809 PushDeclContext(Namespc->getOriginalNamespace()); 810 return Namespc; 811} 812 813/// ActOnFinishNamespaceDef - This callback is called after a namespace is 814/// exited. Decl is the DeclTy returned by ActOnStartNamespaceDef. 815void Sema::ActOnFinishNamespaceDef(DeclTy *D, SourceLocation RBrace) { 816 Decl *Dcl = static_cast<Decl *>(D); 817 NamespaceDecl *Namespc = dyn_cast_or_null<NamespaceDecl>(Dcl); 818 assert(Namespc && "Invalid parameter, expected NamespaceDecl"); 819 Namespc->setRBracLoc(RBrace); 820 PopDeclContext(); 821} 822 823 824/// AddCXXDirectInitializerToDecl - This action is called immediately after 825/// ActOnDeclarator, when a C++ direct initializer is present. 826/// e.g: "int x(1);" 827void Sema::AddCXXDirectInitializerToDecl(DeclTy *Dcl, SourceLocation LParenLoc, 828 ExprTy **ExprTys, unsigned NumExprs, 829 SourceLocation *CommaLocs, 830 SourceLocation RParenLoc) { 831 assert(NumExprs != 0 && ExprTys && "missing expressions"); 832 Decl *RealDecl = static_cast<Decl *>(Dcl); 833 834 // If there is no declaration, there was an error parsing it. Just ignore 835 // the initializer. 836 if (RealDecl == 0) { 837 for (unsigned i = 0; i != NumExprs; ++i) 838 delete static_cast<Expr *>(ExprTys[i]); 839 return; 840 } 841 842 VarDecl *VDecl = dyn_cast<VarDecl>(RealDecl); 843 if (!VDecl) { 844 Diag(RealDecl->getLocation(), diag::err_illegal_initializer); 845 RealDecl->setInvalidDecl(); 846 return; 847 } 848 849 // We will treat direct-initialization as a copy-initialization: 850 // int x(1); -as-> int x = 1; 851 // ClassType x(a,b,c); -as-> ClassType x = ClassType(a,b,c); 852 // 853 // Clients that want to distinguish between the two forms, can check for 854 // direct initializer using VarDecl::hasCXXDirectInitializer(). 855 // A major benefit is that clients that don't particularly care about which 856 // exactly form was it (like the CodeGen) can handle both cases without 857 // special case code. 858 859 // C++ 8.5p11: 860 // The form of initialization (using parentheses or '=') is generally 861 // insignificant, but does matter when the entity being initialized has a 862 // class type. 863 QualType DeclInitType = VDecl->getType(); 864 if (const ArrayType *Array = Context.getAsArrayType(DeclInitType)) 865 DeclInitType = Array->getElementType(); 866 867 if (VDecl->getType()->isRecordType()) { 868 CXXConstructorDecl *Constructor 869 = PerformDirectInitForClassType(DeclInitType, (Expr **)ExprTys, NumExprs, 870 VDecl->getLocation(), 871 SourceRange(VDecl->getLocation(), 872 RParenLoc), 873 VDecl->getName(), 874 /*HasInitializer=*/true); 875 if (!Constructor) { 876 RealDecl->setInvalidDecl(); 877 } 878 return; 879 } 880 881 if (NumExprs > 1) { 882 Diag(CommaLocs[0], diag::err_builtin_direct_init_more_than_one_arg, 883 SourceRange(VDecl->getLocation(), RParenLoc)); 884 RealDecl->setInvalidDecl(); 885 return; 886 } 887 888 // Let clients know that initialization was done with a direct initializer. 889 VDecl->setCXXDirectInitializer(true); 890 891 assert(NumExprs == 1 && "Expected 1 expression"); 892 // Set the init expression, handles conversions. 893 AddInitializerToDecl(Dcl, ExprTys[0]); 894} 895 896/// PerformDirectInitForClassType - Perform direct-initialization (C++ 897/// [dcl.init]) for a value of the given class type with the given set 898/// of arguments (@p Args). @p Loc is the location in the source code 899/// where the initializer occurs (e.g., a declaration, member 900/// initializer, functional cast, etc.) while @p Range covers the 901/// whole initialization. @p HasInitializer is true if the initializer 902/// was actually written in the source code. When successful, returns 903/// the constructor that will be used to perform the initialization; 904/// when the initialization fails, emits a diagnostic and returns null. 905CXXConstructorDecl * 906Sema::PerformDirectInitForClassType(QualType ClassType, 907 Expr **Args, unsigned NumArgs, 908 SourceLocation Loc, SourceRange Range, 909 std::string InitEntity, 910 bool HasInitializer) { 911 const RecordType *ClassRec = ClassType->getAsRecordType(); 912 assert(ClassRec && "Can only initialize a class type here"); 913 914 // C++ [dcl.init]p14: 915 // 916 // If the initialization is direct-initialization, or if it is 917 // copy-initialization where the cv-unqualified version of the 918 // source type is the same class as, or a derived class of, the 919 // class of the destination, constructors are considered. The 920 // applicable constructors are enumerated (13.3.1.3), and the 921 // best one is chosen through overload resolution (13.3). The 922 // constructor so selected is called to initialize the object, 923 // with the initializer expression(s) as its argument(s). If no 924 // constructor applies, or the overload resolution is ambiguous, 925 // the initialization is ill-formed. 926 // 927 // FIXME: We don't check cv-qualifiers on the class type, because we 928 // don't yet keep track of whether a class type is a POD class type 929 // (or a "trivial" class type, as is used in C++0x). 930 const CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(ClassRec->getDecl()); 931 OverloadCandidateSet CandidateSet; 932 OverloadCandidateSet::iterator Best; 933 AddOverloadCandidates(ClassDecl->getConstructors(), Args, NumArgs, 934 CandidateSet); 935 switch (BestViableFunction(CandidateSet, Best)) { 936 case OR_Success: 937 // We found a constructor. Return it. 938 return cast<CXXConstructorDecl>(Best->Function); 939 940 case OR_No_Viable_Function: 941 if (CandidateSet.empty()) 942 Diag(Loc, diag::err_ovl_no_viable_function_in_init, 943 InitEntity, Range); 944 else { 945 Diag(Loc, diag::err_ovl_no_viable_function_in_init_with_cands, 946 InitEntity, Range); 947 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 948 } 949 return 0; 950 951 case OR_Ambiguous: 952 Diag(Loc, diag::err_ovl_ambiguous_init, 953 InitEntity, Range); 954 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 955 return 0; 956 } 957 958 return 0; 959} 960 961/// CompareReferenceRelationship - Compare the two types T1 and T2 to 962/// determine whether they are reference-related, 963/// reference-compatible, reference-compatible with added 964/// qualification, or incompatible, for use in C++ initialization by 965/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 966/// type, and the first type (T1) is the pointee type of the reference 967/// type being initialized. 968Sema::ReferenceCompareResult 969Sema::CompareReferenceRelationship(QualType T1, QualType T2, 970 bool& DerivedToBase) { 971 assert(!T1->isReferenceType() && "T1 must be the pointee type of the reference type"); 972 assert(!T2->isReferenceType() && "T2 cannot be a reference type"); 973 974 T1 = Context.getCanonicalType(T1); 975 T2 = Context.getCanonicalType(T2); 976 QualType UnqualT1 = T1.getUnqualifiedType(); 977 QualType UnqualT2 = T2.getUnqualifiedType(); 978 979 // C++ [dcl.init.ref]p4: 980 // Given types “cv1 T1” and “cv2 T2,” “cv1 T1” is 981 // reference-related to “cv2 T2” if T1 is the same type as T2, or 982 // T1 is a base class of T2. 983 if (UnqualT1 == UnqualT2) 984 DerivedToBase = false; 985 else if (IsDerivedFrom(UnqualT2, UnqualT1)) 986 DerivedToBase = true; 987 else 988 return Ref_Incompatible; 989 990 // At this point, we know that T1 and T2 are reference-related (at 991 // least). 992 993 // C++ [dcl.init.ref]p4: 994 // "cv1 T1” is reference-compatible with “cv2 T2” if T1 is 995 // reference-related to T2 and cv1 is the same cv-qualification 996 // as, or greater cv-qualification than, cv2. For purposes of 997 // overload resolution, cases for which cv1 is greater 998 // cv-qualification than cv2 are identified as 999 // reference-compatible with added qualification (see 13.3.3.2). 1000 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1001 return Ref_Compatible; 1002 else if (T1.isMoreQualifiedThan(T2)) 1003 return Ref_Compatible_With_Added_Qualification; 1004 else 1005 return Ref_Related; 1006} 1007 1008/// CheckReferenceInit - Check the initialization of a reference 1009/// variable with the given initializer (C++ [dcl.init.ref]). Init is 1010/// the initializer (either a simple initializer or an initializer 1011/// list), and DeclType is the type of the declaration. When ICS is 1012/// non-null, this routine will compute the implicit conversion 1013/// sequence according to C++ [over.ics.ref] and will not produce any 1014/// diagnostics; when ICS is null, it will emit diagnostics when any 1015/// errors are found. Either way, a return value of true indicates 1016/// that there was a failure, a return value of false indicates that 1017/// the reference initialization succeeded. 1018/// 1019/// When @p SuppressUserConversions, user-defined conversions are 1020/// suppressed. 1021bool 1022Sema::CheckReferenceInit(Expr *&Init, QualType &DeclType, 1023 ImplicitConversionSequence *ICS, 1024 bool SuppressUserConversions) { 1025 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 1026 1027 QualType T1 = DeclType->getAsReferenceType()->getPointeeType(); 1028 QualType T2 = Init->getType(); 1029 1030 // Compute some basic properties of the types and the initializer. 1031 bool DerivedToBase = false; 1032 Expr::isLvalueResult InitLvalue = Init->isLvalue(Context); 1033 ReferenceCompareResult RefRelationship 1034 = CompareReferenceRelationship(T1, T2, DerivedToBase); 1035 1036 // Most paths end in a failed conversion. 1037 if (ICS) 1038 ICS->ConversionKind = ImplicitConversionSequence::BadConversion; 1039 1040 // C++ [dcl.init.ref]p5: 1041 // A reference to type “cv1 T1” is initialized by an expression 1042 // of type “cv2 T2” as follows: 1043 1044 // -- If the initializer expression 1045 1046 bool BindsDirectly = false; 1047 // -- is an lvalue (but is not a bit-field), and “cv1 T1” is 1048 // reference-compatible with “cv2 T2,” or 1049 // 1050 // Note that the bit-field check is skipped if we are just computing 1051 // the implicit conversion sequence (C++ [over.best.ics]p2). 1052 if (InitLvalue == Expr::LV_Valid && (ICS || !Init->isBitField()) && 1053 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1054 BindsDirectly = true; 1055 1056 if (ICS) { 1057 // C++ [over.ics.ref]p1: 1058 // When a parameter of reference type binds directly (8.5.3) 1059 // to an argument expression, the implicit conversion sequence 1060 // is the identity conversion, unless the argument expression 1061 // has a type that is a derived class of the parameter type, 1062 // in which case the implicit conversion sequence is a 1063 // derived-to-base Conversion (13.3.3.1). 1064 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1065 ICS->Standard.First = ICK_Identity; 1066 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1067 ICS->Standard.Third = ICK_Identity; 1068 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1069 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1070 ICS->Standard.ReferenceBinding = true; 1071 ICS->Standard.DirectBinding = true; 1072 1073 // Nothing more to do: the inaccessibility/ambiguity check for 1074 // derived-to-base conversions is suppressed when we're 1075 // computing the implicit conversion sequence (C++ 1076 // [over.best.ics]p2). 1077 return false; 1078 } else { 1079 // Perform the conversion. 1080 // FIXME: Binding to a subobject of the lvalue is going to require 1081 // more AST annotation than this. 1082 ImpCastExprToType(Init, T1); 1083 } 1084 } 1085 1086 // -- has a class type (i.e., T2 is a class type) and can be 1087 // implicitly converted to an lvalue of type “cv3 T3,” 1088 // where “cv1 T1” is reference-compatible with “cv3 T3” 1089 // 92) (this conversion is selected by enumerating the 1090 // applicable conversion functions (13.3.1.6) and choosing 1091 // the best one through overload resolution (13.3)), 1092 // FIXME: Implement this second bullet, once we have conversion 1093 // functions. Also remember C++ [over.ics.ref]p1, second part. 1094 1095 if (BindsDirectly) { 1096 // C++ [dcl.init.ref]p4: 1097 // [...] In all cases where the reference-related or 1098 // reference-compatible relationship of two types is used to 1099 // establish the validity of a reference binding, and T1 is a 1100 // base class of T2, a program that necessitates such a binding 1101 // is ill-formed if T1 is an inaccessible (clause 11) or 1102 // ambiguous (10.2) base class of T2. 1103 // 1104 // Note that we only check this condition when we're allowed to 1105 // complain about errors, because we should not be checking for 1106 // ambiguity (or inaccessibility) unless the reference binding 1107 // actually happens. 1108 if (DerivedToBase) 1109 return CheckDerivedToBaseConversion(T2, T1, 1110 Init->getSourceRange().getBegin(), 1111 Init->getSourceRange()); 1112 else 1113 return false; 1114 } 1115 1116 // -- Otherwise, the reference shall be to a non-volatile const 1117 // type (i.e., cv1 shall be const). 1118 if (T1.getCVRQualifiers() != QualType::Const) { 1119 if (!ICS) 1120 Diag(Init->getSourceRange().getBegin(), 1121 diag::err_not_reference_to_const_init, 1122 T1.getAsString(), 1123 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1124 T2.getAsString(), Init->getSourceRange()); 1125 return true; 1126 } 1127 1128 // -- If the initializer expression is an rvalue, with T2 a 1129 // class type, and “cv1 T1” is reference-compatible with 1130 // “cv2 T2,” the reference is bound in one of the 1131 // following ways (the choice is implementation-defined): 1132 // 1133 // -- The reference is bound to the object represented by 1134 // the rvalue (see 3.10) or to a sub-object within that 1135 // object. 1136 // 1137 // -- A temporary of type “cv1 T2” [sic] is created, and 1138 // a constructor is called to copy the entire rvalue 1139 // object into the temporary. The reference is bound to 1140 // the temporary or to a sub-object within the 1141 // temporary. 1142 // 1143 // 1144 // The constructor that would be used to make the copy 1145 // shall be callable whether or not the copy is actually 1146 // done. 1147 // 1148 // Note that C++0x [dcl.ref.init]p5 takes away this implementation 1149 // freedom, so we will always take the first option and never build 1150 // a temporary in this case. FIXME: We will, however, have to check 1151 // for the presence of a copy constructor in C++98/03 mode. 1152 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 1153 RefRelationship >= Ref_Compatible_With_Added_Qualification) { 1154 if (ICS) { 1155 ICS->ConversionKind = ImplicitConversionSequence::StandardConversion; 1156 ICS->Standard.First = ICK_Identity; 1157 ICS->Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 1158 ICS->Standard.Third = ICK_Identity; 1159 ICS->Standard.FromTypePtr = T2.getAsOpaquePtr(); 1160 ICS->Standard.ToTypePtr = T1.getAsOpaquePtr(); 1161 ICS->Standard.ReferenceBinding = true; 1162 ICS->Standard.DirectBinding = false; 1163 } else { 1164 // FIXME: Binding to a subobject of the rvalue is going to require 1165 // more AST annotation than this. 1166 ImpCastExprToType(Init, T1); 1167 } 1168 return false; 1169 } 1170 1171 // -- Otherwise, a temporary of type “cv1 T1” is created and 1172 // initialized from the initializer expression using the 1173 // rules for a non-reference copy initialization (8.5). The 1174 // reference is then bound to the temporary. If T1 is 1175 // reference-related to T2, cv1 must be the same 1176 // cv-qualification as, or greater cv-qualification than, 1177 // cv2; otherwise, the program is ill-formed. 1178 if (RefRelationship == Ref_Related) { 1179 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 1180 // we would be reference-compatible or reference-compatible with 1181 // added qualification. But that wasn't the case, so the reference 1182 // initialization fails. 1183 if (!ICS) 1184 Diag(Init->getSourceRange().getBegin(), 1185 diag::err_reference_init_drops_quals, 1186 T1.getAsString(), 1187 InitLvalue != Expr::LV_Valid? "temporary" : "value", 1188 T2.getAsString(), Init->getSourceRange()); 1189 return true; 1190 } 1191 1192 // Actually try to convert the initializer to T1. 1193 if (ICS) { 1194 /// C++ [over.ics.ref]p2: 1195 /// 1196 /// When a parameter of reference type is not bound directly to 1197 /// an argument expression, the conversion sequence is the one 1198 /// required to convert the argument expression to the 1199 /// underlying type of the reference according to 1200 /// 13.3.3.1. Conceptually, this conversion sequence corresponds 1201 /// to copy-initializing a temporary of the underlying type with 1202 /// the argument expression. Any difference in top-level 1203 /// cv-qualification is subsumed by the initialization itself 1204 /// and does not constitute a conversion. 1205 *ICS = TryImplicitConversion(Init, T1, SuppressUserConversions); 1206 return ICS->ConversionKind == ImplicitConversionSequence::BadConversion; 1207 } else { 1208 return PerformImplicitConversion(Init, T1); 1209 } 1210} 1211