SemaOverload.cpp revision 9dc58bb414394db3b886c0b6425a2738cb4cd785
1//===--- SemaOverload.cpp - C++ Overloading ---------------------*- C++ -*-===// 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 provides Sema routines for C++ overloading. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Sema.h" 15#include "Lookup.h" 16#include "SemaInit.h" 17#include "clang/Basic/Diagnostic.h" 18#include "clang/Lex/Preprocessor.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CXXInheritance.h" 21#include "clang/AST/Expr.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/TypeOrdering.h" 24#include "clang/Basic/PartialDiagnostic.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/STLExtras.h" 27#include <algorithm> 28 29namespace clang { 30 31/// GetConversionCategory - Retrieve the implicit conversion 32/// category corresponding to the given implicit conversion kind. 33ImplicitConversionCategory 34GetConversionCategory(ImplicitConversionKind Kind) { 35 static const ImplicitConversionCategory 36 Category[(int)ICK_Num_Conversion_Kinds] = { 37 ICC_Identity, 38 ICC_Lvalue_Transformation, 39 ICC_Lvalue_Transformation, 40 ICC_Lvalue_Transformation, 41 ICC_Identity, 42 ICC_Qualification_Adjustment, 43 ICC_Promotion, 44 ICC_Promotion, 45 ICC_Promotion, 46 ICC_Conversion, 47 ICC_Conversion, 48 ICC_Conversion, 49 ICC_Conversion, 50 ICC_Conversion, 51 ICC_Conversion, 52 ICC_Conversion, 53 ICC_Conversion, 54 ICC_Conversion, 55 ICC_Conversion 56 }; 57 return Category[(int)Kind]; 58} 59 60/// GetConversionRank - Retrieve the implicit conversion rank 61/// corresponding to the given implicit conversion kind. 62ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) { 63 static const ImplicitConversionRank 64 Rank[(int)ICK_Num_Conversion_Kinds] = { 65 ICR_Exact_Match, 66 ICR_Exact_Match, 67 ICR_Exact_Match, 68 ICR_Exact_Match, 69 ICR_Exact_Match, 70 ICR_Exact_Match, 71 ICR_Promotion, 72 ICR_Promotion, 73 ICR_Promotion, 74 ICR_Conversion, 75 ICR_Conversion, 76 ICR_Conversion, 77 ICR_Conversion, 78 ICR_Conversion, 79 ICR_Conversion, 80 ICR_Conversion, 81 ICR_Conversion, 82 ICR_Conversion, 83 ICR_Complex_Real_Conversion 84 }; 85 return Rank[(int)Kind]; 86} 87 88/// GetImplicitConversionName - Return the name of this kind of 89/// implicit conversion. 90const char* GetImplicitConversionName(ImplicitConversionKind Kind) { 91 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = { 92 "No conversion", 93 "Lvalue-to-rvalue", 94 "Array-to-pointer", 95 "Function-to-pointer", 96 "Noreturn adjustment", 97 "Qualification", 98 "Integral promotion", 99 "Floating point promotion", 100 "Complex promotion", 101 "Integral conversion", 102 "Floating conversion", 103 "Complex conversion", 104 "Floating-integral conversion", 105 "Complex-real conversion", 106 "Pointer conversion", 107 "Pointer-to-member conversion", 108 "Boolean conversion", 109 "Compatible-types conversion", 110 "Derived-to-base conversion" 111 }; 112 return Name[Kind]; 113} 114 115/// StandardConversionSequence - Set the standard conversion 116/// sequence to the identity conversion. 117void StandardConversionSequence::setAsIdentityConversion() { 118 First = ICK_Identity; 119 Second = ICK_Identity; 120 Third = ICK_Identity; 121 DeprecatedStringLiteralToCharPtr = false; 122 ReferenceBinding = false; 123 DirectBinding = false; 124 RRefBinding = false; 125 CopyConstructor = 0; 126} 127 128/// getRank - Retrieve the rank of this standard conversion sequence 129/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 130/// implicit conversions. 131ImplicitConversionRank StandardConversionSequence::getRank() const { 132 ImplicitConversionRank Rank = ICR_Exact_Match; 133 if (GetConversionRank(First) > Rank) 134 Rank = GetConversionRank(First); 135 if (GetConversionRank(Second) > Rank) 136 Rank = GetConversionRank(Second); 137 if (GetConversionRank(Third) > Rank) 138 Rank = GetConversionRank(Third); 139 return Rank; 140} 141 142/// isPointerConversionToBool - Determines whether this conversion is 143/// a conversion of a pointer or pointer-to-member to bool. This is 144/// used as part of the ranking of standard conversion sequences 145/// (C++ 13.3.3.2p4). 146bool StandardConversionSequence::isPointerConversionToBool() const { 147 // Note that FromType has not necessarily been transformed by the 148 // array-to-pointer or function-to-pointer implicit conversions, so 149 // check for their presence as well as checking whether FromType is 150 // a pointer. 151 if (getToType(1)->isBooleanType() && 152 (getFromType()->isPointerType() || getFromType()->isBlockPointerType() || 153 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 154 return true; 155 156 return false; 157} 158 159/// isPointerConversionToVoidPointer - Determines whether this 160/// conversion is a conversion of a pointer to a void pointer. This is 161/// used as part of the ranking of standard conversion sequences (C++ 162/// 13.3.3.2p4). 163bool 164StandardConversionSequence:: 165isPointerConversionToVoidPointer(ASTContext& Context) const { 166 QualType FromType = getFromType(); 167 QualType ToType = getToType(1); 168 169 // Note that FromType has not necessarily been transformed by the 170 // array-to-pointer implicit conversion, so check for its presence 171 // and redo the conversion to get a pointer. 172 if (First == ICK_Array_To_Pointer) 173 FromType = Context.getArrayDecayedType(FromType); 174 175 if (Second == ICK_Pointer_Conversion && FromType->isPointerType()) 176 if (const PointerType* ToPtrType = ToType->getAs<PointerType>()) 177 return ToPtrType->getPointeeType()->isVoidType(); 178 179 return false; 180} 181 182/// DebugPrint - Print this standard conversion sequence to standard 183/// error. Useful for debugging overloading issues. 184void StandardConversionSequence::DebugPrint() const { 185 llvm::raw_ostream &OS = llvm::errs(); 186 bool PrintedSomething = false; 187 if (First != ICK_Identity) { 188 OS << GetImplicitConversionName(First); 189 PrintedSomething = true; 190 } 191 192 if (Second != ICK_Identity) { 193 if (PrintedSomething) { 194 OS << " -> "; 195 } 196 OS << GetImplicitConversionName(Second); 197 198 if (CopyConstructor) { 199 OS << " (by copy constructor)"; 200 } else if (DirectBinding) { 201 OS << " (direct reference binding)"; 202 } else if (ReferenceBinding) { 203 OS << " (reference binding)"; 204 } 205 PrintedSomething = true; 206 } 207 208 if (Third != ICK_Identity) { 209 if (PrintedSomething) { 210 OS << " -> "; 211 } 212 OS << GetImplicitConversionName(Third); 213 PrintedSomething = true; 214 } 215 216 if (!PrintedSomething) { 217 OS << "No conversions required"; 218 } 219} 220 221/// DebugPrint - Print this user-defined conversion sequence to standard 222/// error. Useful for debugging overloading issues. 223void UserDefinedConversionSequence::DebugPrint() const { 224 llvm::raw_ostream &OS = llvm::errs(); 225 if (Before.First || Before.Second || Before.Third) { 226 Before.DebugPrint(); 227 OS << " -> "; 228 } 229 OS << '\'' << ConversionFunction << '\''; 230 if (After.First || After.Second || After.Third) { 231 OS << " -> "; 232 After.DebugPrint(); 233 } 234} 235 236/// DebugPrint - Print this implicit conversion sequence to standard 237/// error. Useful for debugging overloading issues. 238void ImplicitConversionSequence::DebugPrint() const { 239 llvm::raw_ostream &OS = llvm::errs(); 240 switch (ConversionKind) { 241 case StandardConversion: 242 OS << "Standard conversion: "; 243 Standard.DebugPrint(); 244 break; 245 case UserDefinedConversion: 246 OS << "User-defined conversion: "; 247 UserDefined.DebugPrint(); 248 break; 249 case EllipsisConversion: 250 OS << "Ellipsis conversion"; 251 break; 252 case AmbiguousConversion: 253 OS << "Ambiguous conversion"; 254 break; 255 case BadConversion: 256 OS << "Bad conversion"; 257 break; 258 } 259 260 OS << "\n"; 261} 262 263void AmbiguousConversionSequence::construct() { 264 new (&conversions()) ConversionSet(); 265} 266 267void AmbiguousConversionSequence::destruct() { 268 conversions().~ConversionSet(); 269} 270 271void 272AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) { 273 FromTypePtr = O.FromTypePtr; 274 ToTypePtr = O.ToTypePtr; 275 new (&conversions()) ConversionSet(O.conversions()); 276} 277 278 279// IsOverload - Determine whether the given New declaration is an 280// overload of the declarations in Old. This routine returns false if 281// New and Old cannot be overloaded, e.g., if New has the same 282// signature as some function in Old (C++ 1.3.10) or if the Old 283// declarations aren't functions (or function templates) at all. When 284// it does return false, MatchedDecl will point to the decl that New 285// cannot be overloaded with. This decl may be a UsingShadowDecl on 286// top of the underlying declaration. 287// 288// Example: Given the following input: 289// 290// void f(int, float); // #1 291// void f(int, int); // #2 292// int f(int, int); // #3 293// 294// When we process #1, there is no previous declaration of "f", 295// so IsOverload will not be used. 296// 297// When we process #2, Old contains only the FunctionDecl for #1. By 298// comparing the parameter types, we see that #1 and #2 are overloaded 299// (since they have different signatures), so this routine returns 300// false; MatchedDecl is unchanged. 301// 302// When we process #3, Old is an overload set containing #1 and #2. We 303// compare the signatures of #3 to #1 (they're overloaded, so we do 304// nothing) and then #3 to #2. Since the signatures of #3 and #2 are 305// identical (return types of functions are not part of the 306// signature), IsOverload returns false and MatchedDecl will be set to 307// point to the FunctionDecl for #2. 308Sema::OverloadKind 309Sema::CheckOverload(FunctionDecl *New, const LookupResult &Old, 310 NamedDecl *&Match) { 311 for (LookupResult::iterator I = Old.begin(), E = Old.end(); 312 I != E; ++I) { 313 NamedDecl *OldD = (*I)->getUnderlyingDecl(); 314 if (FunctionTemplateDecl *OldT = dyn_cast<FunctionTemplateDecl>(OldD)) { 315 if (!IsOverload(New, OldT->getTemplatedDecl())) { 316 Match = *I; 317 return Ovl_Match; 318 } 319 } else if (FunctionDecl *OldF = dyn_cast<FunctionDecl>(OldD)) { 320 if (!IsOverload(New, OldF)) { 321 Match = *I; 322 return Ovl_Match; 323 } 324 } else if (isa<UsingDecl>(OldD) || isa<TagDecl>(OldD)) { 325 // We can overload with these, which can show up when doing 326 // redeclaration checks for UsingDecls. 327 assert(Old.getLookupKind() == LookupUsingDeclName); 328 } else if (isa<UnresolvedUsingValueDecl>(OldD)) { 329 // Optimistically assume that an unresolved using decl will 330 // overload; if it doesn't, we'll have to diagnose during 331 // template instantiation. 332 } else { 333 // (C++ 13p1): 334 // Only function declarations can be overloaded; object and type 335 // declarations cannot be overloaded. 336 Match = *I; 337 return Ovl_NonFunction; 338 } 339 } 340 341 return Ovl_Overload; 342} 343 344bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old) { 345 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate(); 346 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate(); 347 348 // C++ [temp.fct]p2: 349 // A function template can be overloaded with other function templates 350 // and with normal (non-template) functions. 351 if ((OldTemplate == 0) != (NewTemplate == 0)) 352 return true; 353 354 // Is the function New an overload of the function Old? 355 QualType OldQType = Context.getCanonicalType(Old->getType()); 356 QualType NewQType = Context.getCanonicalType(New->getType()); 357 358 // Compare the signatures (C++ 1.3.10) of the two functions to 359 // determine whether they are overloads. If we find any mismatch 360 // in the signature, they are overloads. 361 362 // If either of these functions is a K&R-style function (no 363 // prototype), then we consider them to have matching signatures. 364 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 365 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 366 return false; 367 368 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType); 369 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType); 370 371 // The signature of a function includes the types of its 372 // parameters (C++ 1.3.10), which includes the presence or absence 373 // of the ellipsis; see C++ DR 357). 374 if (OldQType != NewQType && 375 (OldType->getNumArgs() != NewType->getNumArgs() || 376 OldType->isVariadic() != NewType->isVariadic() || 377 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 378 NewType->arg_type_begin()))) 379 return true; 380 381 // C++ [temp.over.link]p4: 382 // The signature of a function template consists of its function 383 // signature, its return type and its template parameter list. The names 384 // of the template parameters are significant only for establishing the 385 // relationship between the template parameters and the rest of the 386 // signature. 387 // 388 // We check the return type and template parameter lists for function 389 // templates first; the remaining checks follow. 390 if (NewTemplate && 391 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), 392 OldTemplate->getTemplateParameters(), 393 false, TPL_TemplateMatch) || 394 OldType->getResultType() != NewType->getResultType())) 395 return true; 396 397 // If the function is a class member, its signature includes the 398 // cv-qualifiers (if any) on the function itself. 399 // 400 // As part of this, also check whether one of the member functions 401 // is static, in which case they are not overloads (C++ 402 // 13.1p2). While not part of the definition of the signature, 403 // this check is important to determine whether these functions 404 // can be overloaded. 405 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 406 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 407 if (OldMethod && NewMethod && 408 !OldMethod->isStatic() && !NewMethod->isStatic() && 409 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 410 return true; 411 412 // The signatures match; this is not an overload. 413 return false; 414} 415 416/// TryImplicitConversion - Attempt to perform an implicit conversion 417/// from the given expression (Expr) to the given type (ToType). This 418/// function returns an implicit conversion sequence that can be used 419/// to perform the initialization. Given 420/// 421/// void f(float f); 422/// void g(int i) { f(i); } 423/// 424/// this routine would produce an implicit conversion sequence to 425/// describe the initialization of f from i, which will be a standard 426/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 427/// 4.1) followed by a floating-integral conversion (C++ 4.9). 428// 429/// Note that this routine only determines how the conversion can be 430/// performed; it does not actually perform the conversion. As such, 431/// it will not produce any diagnostics if no conversion is available, 432/// but will instead return an implicit conversion sequence of kind 433/// "BadConversion". 434/// 435/// If @p SuppressUserConversions, then user-defined conversions are 436/// not permitted. 437/// If @p AllowExplicit, then explicit user-defined conversions are 438/// permitted. 439ImplicitConversionSequence 440Sema::TryImplicitConversion(Expr* From, QualType ToType, 441 bool SuppressUserConversions, 442 bool AllowExplicit, 443 bool InOverloadResolution) { 444 ImplicitConversionSequence ICS; 445 if (IsStandardConversion(From, ToType, InOverloadResolution, ICS.Standard)) { 446 ICS.setStandard(); 447 return ICS; 448 } 449 450 if (!getLangOptions().CPlusPlus) { 451 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 452 return ICS; 453 } 454 455 if (SuppressUserConversions) { 456 // C++ [over.ics.user]p4: 457 // A conversion of an expression of class type to the same class 458 // type is given Exact Match rank, and a conversion of an 459 // expression of class type to a base class of that type is 460 // given Conversion rank, in spite of the fact that a copy/move 461 // constructor (i.e., a user-defined conversion function) is 462 // called for those cases. 463 QualType FromType = From->getType(); 464 if (!ToType->getAs<RecordType>() || !FromType->getAs<RecordType>() || 465 !(Context.hasSameUnqualifiedType(FromType, ToType) || 466 IsDerivedFrom(FromType, ToType))) { 467 // We're not in the case above, so there is no conversion that 468 // we can perform. 469 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 470 return ICS; 471 } 472 473 ICS.setStandard(); 474 ICS.Standard.setAsIdentityConversion(); 475 ICS.Standard.setFromType(FromType); 476 ICS.Standard.setAllToTypes(ToType); 477 478 // We don't actually check at this point whether there is a valid 479 // copy/move constructor, since overloading just assumes that it 480 // exists. When we actually perform initialization, we'll find the 481 // appropriate constructor to copy the returned object, if needed. 482 ICS.Standard.CopyConstructor = 0; 483 484 // Determine whether this is considered a derived-to-base conversion. 485 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 486 ICS.Standard.Second = ICK_Derived_To_Base; 487 488 return ICS; 489 } 490 491 // Attempt user-defined conversion. 492 OverloadCandidateSet Conversions(From->getExprLoc()); 493 OverloadingResult UserDefResult 494 = IsUserDefinedConversion(From, ToType, ICS.UserDefined, Conversions, 495 AllowExplicit); 496 497 if (UserDefResult == OR_Success) { 498 ICS.setUserDefined(); 499 // C++ [over.ics.user]p4: 500 // A conversion of an expression of class type to the same class 501 // type is given Exact Match rank, and a conversion of an 502 // expression of class type to a base class of that type is 503 // given Conversion rank, in spite of the fact that a copy 504 // constructor (i.e., a user-defined conversion function) is 505 // called for those cases. 506 if (CXXConstructorDecl *Constructor 507 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 508 QualType FromCanon 509 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 510 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 511 if (Constructor->isCopyConstructor() && 512 (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) { 513 // Turn this into a "standard" conversion sequence, so that it 514 // gets ranked with standard conversion sequences. 515 ICS.setStandard(); 516 ICS.Standard.setAsIdentityConversion(); 517 ICS.Standard.setFromType(From->getType()); 518 ICS.Standard.setAllToTypes(ToType); 519 ICS.Standard.CopyConstructor = Constructor; 520 if (ToCanon != FromCanon) 521 ICS.Standard.Second = ICK_Derived_To_Base; 522 } 523 } 524 525 // C++ [over.best.ics]p4: 526 // However, when considering the argument of a user-defined 527 // conversion function that is a candidate by 13.3.1.3 when 528 // invoked for the copying of the temporary in the second step 529 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 530 // 13.3.1.6 in all cases, only standard conversion sequences and 531 // ellipsis conversion sequences are allowed. 532 if (SuppressUserConversions && ICS.isUserDefined()) { 533 ICS.setBad(BadConversionSequence::suppressed_user, From, ToType); 534 } 535 } else if (UserDefResult == OR_Ambiguous && !SuppressUserConversions) { 536 ICS.setAmbiguous(); 537 ICS.Ambiguous.setFromType(From->getType()); 538 ICS.Ambiguous.setToType(ToType); 539 for (OverloadCandidateSet::iterator Cand = Conversions.begin(); 540 Cand != Conversions.end(); ++Cand) 541 if (Cand->Viable) 542 ICS.Ambiguous.addConversion(Cand->Function); 543 } else { 544 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 545 } 546 547 return ICS; 548} 549 550/// PerformImplicitConversion - Perform an implicit conversion of the 551/// expression From to the type ToType. Returns true if there was an 552/// error, false otherwise. The expression From is replaced with the 553/// converted expression. Flavor is the kind of conversion we're 554/// performing, used in the error message. If @p AllowExplicit, 555/// explicit user-defined conversions are permitted. 556bool 557Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 558 AssignmentAction Action, bool AllowExplicit) { 559 ImplicitConversionSequence ICS; 560 return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS); 561} 562 563bool 564Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 565 AssignmentAction Action, bool AllowExplicit, 566 ImplicitConversionSequence& ICS) { 567 ICS = TryImplicitConversion(From, ToType, 568 /*SuppressUserConversions=*/false, 569 AllowExplicit, 570 /*InOverloadResolution=*/false); 571 return PerformImplicitConversion(From, ToType, ICS, Action); 572} 573 574/// \brief Determine whether the conversion from FromType to ToType is a valid 575/// conversion that strips "noreturn" off the nested function type. 576static bool IsNoReturnConversion(ASTContext &Context, QualType FromType, 577 QualType ToType, QualType &ResultTy) { 578 if (Context.hasSameUnqualifiedType(FromType, ToType)) 579 return false; 580 581 // Strip the noreturn off the type we're converting from; noreturn can 582 // safely be removed. 583 FromType = Context.getNoReturnType(FromType, false); 584 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 585 return false; 586 587 ResultTy = FromType; 588 return true; 589} 590 591/// IsStandardConversion - Determines whether there is a standard 592/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 593/// expression From to the type ToType. Standard conversion sequences 594/// only consider non-class types; for conversions that involve class 595/// types, use TryImplicitConversion. If a conversion exists, SCS will 596/// contain the standard conversion sequence required to perform this 597/// conversion and this routine will return true. Otherwise, this 598/// routine will return false and the value of SCS is unspecified. 599bool 600Sema::IsStandardConversion(Expr* From, QualType ToType, 601 bool InOverloadResolution, 602 StandardConversionSequence &SCS) { 603 QualType FromType = From->getType(); 604 605 // Standard conversions (C++ [conv]) 606 SCS.setAsIdentityConversion(); 607 SCS.DeprecatedStringLiteralToCharPtr = false; 608 SCS.IncompatibleObjC = false; 609 SCS.setFromType(FromType); 610 SCS.CopyConstructor = 0; 611 612 // There are no standard conversions for class types in C++, so 613 // abort early. When overloading in C, however, we do permit 614 if (FromType->isRecordType() || ToType->isRecordType()) { 615 if (getLangOptions().CPlusPlus) 616 return false; 617 618 // When we're overloading in C, we allow, as standard conversions, 619 } 620 621 // The first conversion can be an lvalue-to-rvalue conversion, 622 // array-to-pointer conversion, or function-to-pointer conversion 623 // (C++ 4p1). 624 625 DeclAccessPair AccessPair; 626 627 // Lvalue-to-rvalue conversion (C++ 4.1): 628 // An lvalue (3.10) of a non-function, non-array type T can be 629 // converted to an rvalue. 630 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 631 if (argIsLvalue == Expr::LV_Valid && 632 !FromType->isFunctionType() && !FromType->isArrayType() && 633 Context.getCanonicalType(FromType) != Context.OverloadTy) { 634 SCS.First = ICK_Lvalue_To_Rvalue; 635 636 // If T is a non-class type, the type of the rvalue is the 637 // cv-unqualified version of T. Otherwise, the type of the rvalue 638 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 639 // just strip the qualifiers because they don't matter. 640 FromType = FromType.getUnqualifiedType(); 641 } else if (FromType->isArrayType()) { 642 // Array-to-pointer conversion (C++ 4.2) 643 SCS.First = ICK_Array_To_Pointer; 644 645 // An lvalue or rvalue of type "array of N T" or "array of unknown 646 // bound of T" can be converted to an rvalue of type "pointer to 647 // T" (C++ 4.2p1). 648 FromType = Context.getArrayDecayedType(FromType); 649 650 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 651 // This conversion is deprecated. (C++ D.4). 652 SCS.DeprecatedStringLiteralToCharPtr = true; 653 654 // For the purpose of ranking in overload resolution 655 // (13.3.3.1.1), this conversion is considered an 656 // array-to-pointer conversion followed by a qualification 657 // conversion (4.4). (C++ 4.2p2) 658 SCS.Second = ICK_Identity; 659 SCS.Third = ICK_Qualification; 660 SCS.setAllToTypes(FromType); 661 return true; 662 } 663 } else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 664 // Function-to-pointer conversion (C++ 4.3). 665 SCS.First = ICK_Function_To_Pointer; 666 667 // An lvalue of function type T can be converted to an rvalue of 668 // type "pointer to T." The result is a pointer to the 669 // function. (C++ 4.3p1). 670 FromType = Context.getPointerType(FromType); 671 } else if (From->getType() == Context.OverloadTy) { 672 if (FunctionDecl *Fn 673 = ResolveAddressOfOverloadedFunction(From, ToType, false, 674 AccessPair)) { 675 // Address of overloaded function (C++ [over.over]). 676 SCS.First = ICK_Function_To_Pointer; 677 678 // We were able to resolve the address of the overloaded function, 679 // so we can convert to the type of that function. 680 FromType = Fn->getType(); 681 if (ToType->isLValueReferenceType()) 682 FromType = Context.getLValueReferenceType(FromType); 683 else if (ToType->isRValueReferenceType()) 684 FromType = Context.getRValueReferenceType(FromType); 685 else if (ToType->isMemberPointerType()) { 686 // Resolve address only succeeds if both sides are member pointers, 687 // but it doesn't have to be the same class. See DR 247. 688 // Note that this means that the type of &Derived::fn can be 689 // Ret (Base::*)(Args) if the fn overload actually found is from the 690 // base class, even if it was brought into the derived class via a 691 // using declaration. The standard isn't clear on this issue at all. 692 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 693 FromType = Context.getMemberPointerType(FromType, 694 Context.getTypeDeclType(M->getParent()).getTypePtr()); 695 } else { 696 FromType = Context.getPointerType(FromType); 697 } 698 } else { 699 return false; 700 } 701 } else { 702 // We don't require any conversions for the first step. 703 SCS.First = ICK_Identity; 704 } 705 SCS.setToType(0, FromType); 706 707 // The second conversion can be an integral promotion, floating 708 // point promotion, integral conversion, floating point conversion, 709 // floating-integral conversion, pointer conversion, 710 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 711 // For overloading in C, this can also be a "compatible-type" 712 // conversion. 713 bool IncompatibleObjC = false; 714 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 715 // The unqualified versions of the types are the same: there's no 716 // conversion to do. 717 SCS.Second = ICK_Identity; 718 } else if (IsIntegralPromotion(From, FromType, ToType)) { 719 // Integral promotion (C++ 4.5). 720 SCS.Second = ICK_Integral_Promotion; 721 FromType = ToType.getUnqualifiedType(); 722 } else if (IsFloatingPointPromotion(FromType, ToType)) { 723 // Floating point promotion (C++ 4.6). 724 SCS.Second = ICK_Floating_Promotion; 725 FromType = ToType.getUnqualifiedType(); 726 } else if (IsComplexPromotion(FromType, ToType)) { 727 // Complex promotion (Clang extension) 728 SCS.Second = ICK_Complex_Promotion; 729 FromType = ToType.getUnqualifiedType(); 730 } else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 731 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 732 // Integral conversions (C++ 4.7). 733 SCS.Second = ICK_Integral_Conversion; 734 FromType = ToType.getUnqualifiedType(); 735 } else if (FromType->isComplexType() && ToType->isComplexType()) { 736 // Complex conversions (C99 6.3.1.6) 737 SCS.Second = ICK_Complex_Conversion; 738 FromType = ToType.getUnqualifiedType(); 739 } else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 740 (ToType->isComplexType() && FromType->isArithmeticType())) { 741 // Complex-real conversions (C99 6.3.1.7) 742 SCS.Second = ICK_Complex_Real; 743 FromType = ToType.getUnqualifiedType(); 744 } else if (FromType->isFloatingType() && ToType->isFloatingType()) { 745 // Floating point conversions (C++ 4.8). 746 SCS.Second = ICK_Floating_Conversion; 747 FromType = ToType.getUnqualifiedType(); 748 } else if ((FromType->isFloatingType() && 749 ToType->isIntegralType() && (!ToType->isBooleanType() && 750 !ToType->isEnumeralType())) || 751 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 752 ToType->isFloatingType())) { 753 // Floating-integral conversions (C++ 4.9). 754 SCS.Second = ICK_Floating_Integral; 755 FromType = ToType.getUnqualifiedType(); 756 } else if (IsPointerConversion(From, FromType, ToType, InOverloadResolution, 757 FromType, IncompatibleObjC)) { 758 // Pointer conversions (C++ 4.10). 759 SCS.Second = ICK_Pointer_Conversion; 760 SCS.IncompatibleObjC = IncompatibleObjC; 761 } else if (IsMemberPointerConversion(From, FromType, ToType, 762 InOverloadResolution, FromType)) { 763 // Pointer to member conversions (4.11). 764 SCS.Second = ICK_Pointer_Member; 765 } else if (ToType->isBooleanType() && 766 (FromType->isArithmeticType() || 767 FromType->isEnumeralType() || 768 FromType->isAnyPointerType() || 769 FromType->isBlockPointerType() || 770 FromType->isMemberPointerType() || 771 FromType->isNullPtrType())) { 772 // Boolean conversions (C++ 4.12). 773 SCS.Second = ICK_Boolean_Conversion; 774 FromType = Context.BoolTy; 775 } else if (!getLangOptions().CPlusPlus && 776 Context.typesAreCompatible(ToType, FromType)) { 777 // Compatible conversions (Clang extension for C function overloading) 778 SCS.Second = ICK_Compatible_Conversion; 779 } else if (IsNoReturnConversion(Context, FromType, ToType, FromType)) { 780 // Treat a conversion that strips "noreturn" as an identity conversion. 781 SCS.Second = ICK_NoReturn_Adjustment; 782 } else { 783 // No second conversion required. 784 SCS.Second = ICK_Identity; 785 } 786 SCS.setToType(1, FromType); 787 788 QualType CanonFrom; 789 QualType CanonTo; 790 // The third conversion can be a qualification conversion (C++ 4p1). 791 if (IsQualificationConversion(FromType, ToType)) { 792 SCS.Third = ICK_Qualification; 793 FromType = ToType; 794 CanonFrom = Context.getCanonicalType(FromType); 795 CanonTo = Context.getCanonicalType(ToType); 796 } else { 797 // No conversion required 798 SCS.Third = ICK_Identity; 799 800 // C++ [over.best.ics]p6: 801 // [...] Any difference in top-level cv-qualification is 802 // subsumed by the initialization itself and does not constitute 803 // a conversion. [...] 804 CanonFrom = Context.getCanonicalType(FromType); 805 CanonTo = Context.getCanonicalType(ToType); 806 if (CanonFrom.getLocalUnqualifiedType() 807 == CanonTo.getLocalUnqualifiedType() && 808 CanonFrom.getLocalCVRQualifiers() != CanonTo.getLocalCVRQualifiers()) { 809 FromType = ToType; 810 CanonFrom = CanonTo; 811 } 812 } 813 SCS.setToType(2, FromType); 814 815 // If we have not converted the argument type to the parameter type, 816 // this is a bad conversion sequence. 817 if (CanonFrom != CanonTo) 818 return false; 819 820 return true; 821} 822 823/// IsIntegralPromotion - Determines whether the conversion from the 824/// expression From (whose potentially-adjusted type is FromType) to 825/// ToType is an integral promotion (C++ 4.5). If so, returns true and 826/// sets PromotedType to the promoted type. 827bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { 828 const BuiltinType *To = ToType->getAs<BuiltinType>(); 829 // All integers are built-in. 830 if (!To) { 831 return false; 832 } 833 834 // An rvalue of type char, signed char, unsigned char, short int, or 835 // unsigned short int can be converted to an rvalue of type int if 836 // int can represent all the values of the source type; otherwise, 837 // the source rvalue can be converted to an rvalue of type unsigned 838 // int (C++ 4.5p1). 839 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && 840 !FromType->isEnumeralType()) { 841 if (// We can promote any signed, promotable integer type to an int 842 (FromType->isSignedIntegerType() || 843 // We can promote any unsigned integer type whose size is 844 // less than int to an int. 845 (!FromType->isSignedIntegerType() && 846 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 847 return To->getKind() == BuiltinType::Int; 848 } 849 850 return To->getKind() == BuiltinType::UInt; 851 } 852 853 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 854 // can be converted to an rvalue of the first of the following types 855 // that can represent all the values of its underlying type: int, 856 // unsigned int, long, or unsigned long (C++ 4.5p2). 857 858 // We pre-calculate the promotion type for enum types. 859 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) 860 if (ToType->isIntegerType()) 861 return Context.hasSameUnqualifiedType(ToType, 862 FromEnumType->getDecl()->getPromotionType()); 863 864 if (FromType->isWideCharType() && ToType->isIntegerType()) { 865 // Determine whether the type we're converting from is signed or 866 // unsigned. 867 bool FromIsSigned; 868 uint64_t FromSize = Context.getTypeSize(FromType); 869 870 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 871 FromIsSigned = true; 872 873 // The types we'll try to promote to, in the appropriate 874 // order. Try each of these types. 875 QualType PromoteTypes[6] = { 876 Context.IntTy, Context.UnsignedIntTy, 877 Context.LongTy, Context.UnsignedLongTy , 878 Context.LongLongTy, Context.UnsignedLongLongTy 879 }; 880 for (int Idx = 0; Idx < 6; ++Idx) { 881 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 882 if (FromSize < ToSize || 883 (FromSize == ToSize && 884 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 885 // We found the type that we can promote to. If this is the 886 // type we wanted, we have a promotion. Otherwise, no 887 // promotion. 888 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); 889 } 890 } 891 } 892 893 // An rvalue for an integral bit-field (9.6) can be converted to an 894 // rvalue of type int if int can represent all the values of the 895 // bit-field; otherwise, it can be converted to unsigned int if 896 // unsigned int can represent all the values of the bit-field. If 897 // the bit-field is larger yet, no integral promotion applies to 898 // it. If the bit-field has an enumerated type, it is treated as any 899 // other value of that type for promotion purposes (C++ 4.5p3). 900 // FIXME: We should delay checking of bit-fields until we actually perform the 901 // conversion. 902 using llvm::APSInt; 903 if (From) 904 if (FieldDecl *MemberDecl = From->getBitField()) { 905 APSInt BitWidth; 906 if (FromType->isIntegralType() && !FromType->isEnumeralType() && 907 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { 908 APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned()); 909 ToSize = Context.getTypeSize(ToType); 910 911 // Are we promoting to an int from a bitfield that fits in an int? 912 if (BitWidth < ToSize || 913 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 914 return To->getKind() == BuiltinType::Int; 915 } 916 917 // Are we promoting to an unsigned int from an unsigned bitfield 918 // that fits into an unsigned int? 919 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 920 return To->getKind() == BuiltinType::UInt; 921 } 922 923 return false; 924 } 925 } 926 927 // An rvalue of type bool can be converted to an rvalue of type int, 928 // with false becoming zero and true becoming one (C++ 4.5p4). 929 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 930 return true; 931 } 932 933 return false; 934} 935 936/// IsFloatingPointPromotion - Determines whether the conversion from 937/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 938/// returns true and sets PromotedType to the promoted type. 939bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { 940 /// An rvalue of type float can be converted to an rvalue of type 941 /// double. (C++ 4.6p1). 942 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) 943 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { 944 if (FromBuiltin->getKind() == BuiltinType::Float && 945 ToBuiltin->getKind() == BuiltinType::Double) 946 return true; 947 948 // C99 6.3.1.5p1: 949 // When a float is promoted to double or long double, or a 950 // double is promoted to long double [...]. 951 if (!getLangOptions().CPlusPlus && 952 (FromBuiltin->getKind() == BuiltinType::Float || 953 FromBuiltin->getKind() == BuiltinType::Double) && 954 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 955 return true; 956 } 957 958 return false; 959} 960 961/// \brief Determine if a conversion is a complex promotion. 962/// 963/// A complex promotion is defined as a complex -> complex conversion 964/// where the conversion between the underlying real types is a 965/// floating-point or integral promotion. 966bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 967 const ComplexType *FromComplex = FromType->getAs<ComplexType>(); 968 if (!FromComplex) 969 return false; 970 971 const ComplexType *ToComplex = ToType->getAs<ComplexType>(); 972 if (!ToComplex) 973 return false; 974 975 return IsFloatingPointPromotion(FromComplex->getElementType(), 976 ToComplex->getElementType()) || 977 IsIntegralPromotion(0, FromComplex->getElementType(), 978 ToComplex->getElementType()); 979} 980 981/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 982/// the pointer type FromPtr to a pointer to type ToPointee, with the 983/// same type qualifiers as FromPtr has on its pointee type. ToType, 984/// if non-empty, will be a pointer to ToType that may or may not have 985/// the right set of qualifiers on its pointee. 986static QualType 987BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 988 QualType ToPointee, QualType ToType, 989 ASTContext &Context) { 990 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 991 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 992 Qualifiers Quals = CanonFromPointee.getQualifiers(); 993 994 // Exact qualifier match -> return the pointer type we're converting to. 995 if (CanonToPointee.getLocalQualifiers() == Quals) { 996 // ToType is exactly what we need. Return it. 997 if (!ToType.isNull()) 998 return ToType; 999 1000 // Build a pointer to ToPointee. It has the right qualifiers 1001 // already. 1002 return Context.getPointerType(ToPointee); 1003 } 1004 1005 // Just build a canonical type that has the right qualifiers. 1006 return Context.getPointerType( 1007 Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), 1008 Quals)); 1009} 1010 1011/// BuildSimilarlyQualifiedObjCObjectPointerType - In a pointer conversion from 1012/// the FromType, which is an objective-c pointer, to ToType, which may or may 1013/// not have the right set of qualifiers. 1014static QualType 1015BuildSimilarlyQualifiedObjCObjectPointerType(QualType FromType, 1016 QualType ToType, 1017 ASTContext &Context) { 1018 QualType CanonFromType = Context.getCanonicalType(FromType); 1019 QualType CanonToType = Context.getCanonicalType(ToType); 1020 Qualifiers Quals = CanonFromType.getQualifiers(); 1021 1022 // Exact qualifier match -> return the pointer type we're converting to. 1023 if (CanonToType.getLocalQualifiers() == Quals) 1024 return ToType; 1025 1026 // Just build a canonical type that has the right qualifiers. 1027 return Context.getQualifiedType(CanonToType.getLocalUnqualifiedType(), Quals); 1028} 1029 1030static bool isNullPointerConstantForConversion(Expr *Expr, 1031 bool InOverloadResolution, 1032 ASTContext &Context) { 1033 // Handle value-dependent integral null pointer constants correctly. 1034 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 1035 if (Expr->isValueDependent() && !Expr->isTypeDependent() && 1036 Expr->getType()->isIntegralType()) 1037 return !InOverloadResolution; 1038 1039 return Expr->isNullPointerConstant(Context, 1040 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1041 : Expr::NPC_ValueDependentIsNull); 1042} 1043 1044/// IsPointerConversion - Determines whether the conversion of the 1045/// expression From, which has the (possibly adjusted) type FromType, 1046/// can be converted to the type ToType via a pointer conversion (C++ 1047/// 4.10). If so, returns true and places the converted type (that 1048/// might differ from ToType in its cv-qualifiers at some level) into 1049/// ConvertedType. 1050/// 1051/// This routine also supports conversions to and from block pointers 1052/// and conversions with Objective-C's 'id', 'id<protocols...>', and 1053/// pointers to interfaces. FIXME: Once we've determined the 1054/// appropriate overloading rules for Objective-C, we may want to 1055/// split the Objective-C checks into a different routine; however, 1056/// GCC seems to consider all of these conversions to be pointer 1057/// conversions, so for now they live here. IncompatibleObjC will be 1058/// set if the conversion is an allowed Objective-C conversion that 1059/// should result in a warning. 1060bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 1061 bool InOverloadResolution, 1062 QualType& ConvertedType, 1063 bool &IncompatibleObjC) { 1064 IncompatibleObjC = false; 1065 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 1066 return true; 1067 1068 // Conversion from a null pointer constant to any Objective-C pointer type. 1069 if (ToType->isObjCObjectPointerType() && 1070 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1071 ConvertedType = ToType; 1072 return true; 1073 } 1074 1075 // Blocks: Block pointers can be converted to void*. 1076 if (FromType->isBlockPointerType() && ToType->isPointerType() && 1077 ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) { 1078 ConvertedType = ToType; 1079 return true; 1080 } 1081 // Blocks: A null pointer constant can be converted to a block 1082 // pointer type. 1083 if (ToType->isBlockPointerType() && 1084 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1085 ConvertedType = ToType; 1086 return true; 1087 } 1088 1089 // If the left-hand-side is nullptr_t, the right side can be a null 1090 // pointer constant. 1091 if (ToType->isNullPtrType() && 1092 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1093 ConvertedType = ToType; 1094 return true; 1095 } 1096 1097 const PointerType* ToTypePtr = ToType->getAs<PointerType>(); 1098 if (!ToTypePtr) 1099 return false; 1100 1101 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 1102 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1103 ConvertedType = ToType; 1104 return true; 1105 } 1106 1107 // Beyond this point, both types need to be pointers 1108 // , including objective-c pointers. 1109 QualType ToPointeeType = ToTypePtr->getPointeeType(); 1110 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType()) { 1111 ConvertedType = BuildSimilarlyQualifiedObjCObjectPointerType(FromType, 1112 ToType, Context); 1113 return true; 1114 1115 } 1116 const PointerType *FromTypePtr = FromType->getAs<PointerType>(); 1117 if (!FromTypePtr) 1118 return false; 1119 1120 QualType FromPointeeType = FromTypePtr->getPointeeType(); 1121 1122 // An rvalue of type "pointer to cv T," where T is an object type, 1123 // can be converted to an rvalue of type "pointer to cv void" (C++ 1124 // 4.10p2). 1125 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 1126 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1127 ToPointeeType, 1128 ToType, Context); 1129 return true; 1130 } 1131 1132 // When we're overloading in C, we allow a special kind of pointer 1133 // conversion for compatible-but-not-identical pointee types. 1134 if (!getLangOptions().CPlusPlus && 1135 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 1136 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1137 ToPointeeType, 1138 ToType, Context); 1139 return true; 1140 } 1141 1142 // C++ [conv.ptr]p3: 1143 // 1144 // An rvalue of type "pointer to cv D," where D is a class type, 1145 // can be converted to an rvalue of type "pointer to cv B," where 1146 // B is a base class (clause 10) of D. If B is an inaccessible 1147 // (clause 11) or ambiguous (10.2) base class of D, a program that 1148 // necessitates this conversion is ill-formed. The result of the 1149 // conversion is a pointer to the base class sub-object of the 1150 // derived class object. The null pointer value is converted to 1151 // the null pointer value of the destination type. 1152 // 1153 // Note that we do not check for ambiguity or inaccessibility 1154 // here. That is handled by CheckPointerConversion. 1155 if (getLangOptions().CPlusPlus && 1156 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1157 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && 1158 !RequireCompleteType(From->getLocStart(), FromPointeeType, PDiag()) && 1159 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 1160 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1161 ToPointeeType, 1162 ToType, Context); 1163 return true; 1164 } 1165 1166 return false; 1167} 1168 1169/// isObjCPointerConversion - Determines whether this is an 1170/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 1171/// with the same arguments and return values. 1172bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 1173 QualType& ConvertedType, 1174 bool &IncompatibleObjC) { 1175 if (!getLangOptions().ObjC1) 1176 return false; 1177 1178 // First, we handle all conversions on ObjC object pointer types. 1179 const ObjCObjectPointerType* ToObjCPtr = ToType->getAs<ObjCObjectPointerType>(); 1180 const ObjCObjectPointerType *FromObjCPtr = 1181 FromType->getAs<ObjCObjectPointerType>(); 1182 1183 if (ToObjCPtr && FromObjCPtr) { 1184 // Objective C++: We're able to convert between "id" or "Class" and a 1185 // pointer to any interface (in both directions). 1186 if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) { 1187 ConvertedType = ToType; 1188 return true; 1189 } 1190 // Conversions with Objective-C's id<...>. 1191 if ((FromObjCPtr->isObjCQualifiedIdType() || 1192 ToObjCPtr->isObjCQualifiedIdType()) && 1193 Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType, 1194 /*compare=*/false)) { 1195 ConvertedType = ToType; 1196 return true; 1197 } 1198 // Objective C++: We're able to convert from a pointer to an 1199 // interface to a pointer to a different interface. 1200 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { 1201 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); 1202 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); 1203 if (getLangOptions().CPlusPlus && LHS && RHS && 1204 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( 1205 FromObjCPtr->getPointeeType())) 1206 return false; 1207 ConvertedType = ToType; 1208 return true; 1209 } 1210 1211 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { 1212 // Okay: this is some kind of implicit downcast of Objective-C 1213 // interfaces, which is permitted. However, we're going to 1214 // complain about it. 1215 IncompatibleObjC = true; 1216 ConvertedType = FromType; 1217 return true; 1218 } 1219 } 1220 // Beyond this point, both types need to be C pointers or block pointers. 1221 QualType ToPointeeType; 1222 if (const PointerType *ToCPtr = ToType->getAs<PointerType>()) 1223 ToPointeeType = ToCPtr->getPointeeType(); 1224 else if (const BlockPointerType *ToBlockPtr = 1225 ToType->getAs<BlockPointerType>()) { 1226 // Objective C++: We're able to convert from a pointer to any object 1227 // to a block pointer type. 1228 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { 1229 ConvertedType = ToType; 1230 return true; 1231 } 1232 ToPointeeType = ToBlockPtr->getPointeeType(); 1233 } 1234 else if (FromType->getAs<BlockPointerType>() && 1235 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { 1236 // Objective C++: We're able to convert from a block pointer type to a 1237 // pointer to any object. 1238 ConvertedType = ToType; 1239 return true; 1240 } 1241 else 1242 return false; 1243 1244 QualType FromPointeeType; 1245 if (const PointerType *FromCPtr = FromType->getAs<PointerType>()) 1246 FromPointeeType = FromCPtr->getPointeeType(); 1247 else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>()) 1248 FromPointeeType = FromBlockPtr->getPointeeType(); 1249 else 1250 return false; 1251 1252 // If we have pointers to pointers, recursively check whether this 1253 // is an Objective-C conversion. 1254 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1255 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1256 IncompatibleObjC)) { 1257 // We always complain about this conversion. 1258 IncompatibleObjC = true; 1259 ConvertedType = ToType; 1260 return true; 1261 } 1262 // Allow conversion of pointee being objective-c pointer to another one; 1263 // as in I* to id. 1264 if (FromPointeeType->getAs<ObjCObjectPointerType>() && 1265 ToPointeeType->getAs<ObjCObjectPointerType>() && 1266 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1267 IncompatibleObjC)) { 1268 ConvertedType = ToType; 1269 return true; 1270 } 1271 1272 // If we have pointers to functions or blocks, check whether the only 1273 // differences in the argument and result types are in Objective-C 1274 // pointer conversions. If so, we permit the conversion (but 1275 // complain about it). 1276 const FunctionProtoType *FromFunctionType 1277 = FromPointeeType->getAs<FunctionProtoType>(); 1278 const FunctionProtoType *ToFunctionType 1279 = ToPointeeType->getAs<FunctionProtoType>(); 1280 if (FromFunctionType && ToFunctionType) { 1281 // If the function types are exactly the same, this isn't an 1282 // Objective-C pointer conversion. 1283 if (Context.getCanonicalType(FromPointeeType) 1284 == Context.getCanonicalType(ToPointeeType)) 1285 return false; 1286 1287 // Perform the quick checks that will tell us whether these 1288 // function types are obviously different. 1289 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1290 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1291 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1292 return false; 1293 1294 bool HasObjCConversion = false; 1295 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1296 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1297 // Okay, the types match exactly. Nothing to do. 1298 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1299 ToFunctionType->getResultType(), 1300 ConvertedType, IncompatibleObjC)) { 1301 // Okay, we have an Objective-C pointer conversion. 1302 HasObjCConversion = true; 1303 } else { 1304 // Function types are too different. Abort. 1305 return false; 1306 } 1307 1308 // Check argument types. 1309 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1310 ArgIdx != NumArgs; ++ArgIdx) { 1311 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1312 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1313 if (Context.getCanonicalType(FromArgType) 1314 == Context.getCanonicalType(ToArgType)) { 1315 // Okay, the types match exactly. Nothing to do. 1316 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1317 ConvertedType, IncompatibleObjC)) { 1318 // Okay, we have an Objective-C pointer conversion. 1319 HasObjCConversion = true; 1320 } else { 1321 // Argument types are too different. Abort. 1322 return false; 1323 } 1324 } 1325 1326 if (HasObjCConversion) { 1327 // We had an Objective-C conversion. Allow this pointer 1328 // conversion, but complain about it. 1329 ConvertedType = ToType; 1330 IncompatibleObjC = true; 1331 return true; 1332 } 1333 } 1334 1335 return false; 1336} 1337 1338/// CheckPointerConversion - Check the pointer conversion from the 1339/// expression From to the type ToType. This routine checks for 1340/// ambiguous or inaccessible derived-to-base pointer 1341/// conversions for which IsPointerConversion has already returned 1342/// true. It returns true and produces a diagnostic if there was an 1343/// error, or returns false otherwise. 1344bool Sema::CheckPointerConversion(Expr *From, QualType ToType, 1345 CastExpr::CastKind &Kind, 1346 bool IgnoreBaseAccess) { 1347 QualType FromType = From->getType(); 1348 1349 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) 1350 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { 1351 QualType FromPointeeType = FromPtrType->getPointeeType(), 1352 ToPointeeType = ToPtrType->getPointeeType(); 1353 1354 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1355 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { 1356 // We must have a derived-to-base conversion. Check an 1357 // ambiguous or inaccessible conversion. 1358 if (CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1359 From->getExprLoc(), 1360 From->getSourceRange(), 1361 IgnoreBaseAccess)) 1362 return true; 1363 1364 // The conversion was successful. 1365 Kind = CastExpr::CK_DerivedToBase; 1366 } 1367 } 1368 if (const ObjCObjectPointerType *FromPtrType = 1369 FromType->getAs<ObjCObjectPointerType>()) 1370 if (const ObjCObjectPointerType *ToPtrType = 1371 ToType->getAs<ObjCObjectPointerType>()) { 1372 // Objective-C++ conversions are always okay. 1373 // FIXME: We should have a different class of conversions for the 1374 // Objective-C++ implicit conversions. 1375 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) 1376 return false; 1377 1378 } 1379 return false; 1380} 1381 1382/// IsMemberPointerConversion - Determines whether the conversion of the 1383/// expression From, which has the (possibly adjusted) type FromType, can be 1384/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1385/// If so, returns true and places the converted type (that might differ from 1386/// ToType in its cv-qualifiers at some level) into ConvertedType. 1387bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1388 QualType ToType, 1389 bool InOverloadResolution, 1390 QualType &ConvertedType) { 1391 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>(); 1392 if (!ToTypePtr) 1393 return false; 1394 1395 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1396 if (From->isNullPointerConstant(Context, 1397 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1398 : Expr::NPC_ValueDependentIsNull)) { 1399 ConvertedType = ToType; 1400 return true; 1401 } 1402 1403 // Otherwise, both types have to be member pointers. 1404 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>(); 1405 if (!FromTypePtr) 1406 return false; 1407 1408 // A pointer to member of B can be converted to a pointer to member of D, 1409 // where D is derived from B (C++ 4.11p2). 1410 QualType FromClass(FromTypePtr->getClass(), 0); 1411 QualType ToClass(ToTypePtr->getClass(), 0); 1412 // FIXME: What happens when these are dependent? Is this function even called? 1413 1414 if (IsDerivedFrom(ToClass, FromClass)) { 1415 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1416 ToClass.getTypePtr()); 1417 return true; 1418 } 1419 1420 return false; 1421} 1422 1423/// CheckMemberPointerConversion - Check the member pointer conversion from the 1424/// expression From to the type ToType. This routine checks for ambiguous or 1425/// virtual or inaccessible base-to-derived member pointer conversions 1426/// for which IsMemberPointerConversion has already returned true. It returns 1427/// true and produces a diagnostic if there was an error, or returns false 1428/// otherwise. 1429bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, 1430 CastExpr::CastKind &Kind, 1431 bool IgnoreBaseAccess) { 1432 QualType FromType = From->getType(); 1433 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); 1434 if (!FromPtrType) { 1435 // This must be a null pointer to member pointer conversion 1436 assert(From->isNullPointerConstant(Context, 1437 Expr::NPC_ValueDependentIsNull) && 1438 "Expr must be null pointer constant!"); 1439 Kind = CastExpr::CK_NullToMemberPointer; 1440 return false; 1441 } 1442 1443 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>(); 1444 assert(ToPtrType && "No member pointer cast has a target type " 1445 "that is not a member pointer."); 1446 1447 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1448 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1449 1450 // FIXME: What about dependent types? 1451 assert(FromClass->isRecordType() && "Pointer into non-class."); 1452 assert(ToClass->isRecordType() && "Pointer into non-class."); 1453 1454 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/ true, 1455 /*DetectVirtual=*/true); 1456 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1457 assert(DerivationOkay && 1458 "Should not have been called if derivation isn't OK."); 1459 (void)DerivationOkay; 1460 1461 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1462 getUnqualifiedType())) { 1463 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1464 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1465 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1466 return true; 1467 } 1468 1469 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1470 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1471 << FromClass << ToClass << QualType(VBase, 0) 1472 << From->getSourceRange(); 1473 return true; 1474 } 1475 1476 if (!IgnoreBaseAccess) 1477 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, 1478 Paths.front(), 1479 diag::err_downcast_from_inaccessible_base); 1480 1481 // Must be a base to derived member conversion. 1482 Kind = CastExpr::CK_BaseToDerivedMemberPointer; 1483 return false; 1484} 1485 1486/// IsQualificationConversion - Determines whether the conversion from 1487/// an rvalue of type FromType to ToType is a qualification conversion 1488/// (C++ 4.4). 1489bool 1490Sema::IsQualificationConversion(QualType FromType, QualType ToType) { 1491 FromType = Context.getCanonicalType(FromType); 1492 ToType = Context.getCanonicalType(ToType); 1493 1494 // If FromType and ToType are the same type, this is not a 1495 // qualification conversion. 1496 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) 1497 return false; 1498 1499 // (C++ 4.4p4): 1500 // A conversion can add cv-qualifiers at levels other than the first 1501 // in multi-level pointers, subject to the following rules: [...] 1502 bool PreviousToQualsIncludeConst = true; 1503 bool UnwrappedAnyPointer = false; 1504 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1505 // Within each iteration of the loop, we check the qualifiers to 1506 // determine if this still looks like a qualification 1507 // conversion. Then, if all is well, we unwrap one more level of 1508 // pointers or pointers-to-members and do it all again 1509 // until there are no more pointers or pointers-to-members left to 1510 // unwrap. 1511 UnwrappedAnyPointer = true; 1512 1513 // -- for every j > 0, if const is in cv 1,j then const is in cv 1514 // 2,j, and similarly for volatile. 1515 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1516 return false; 1517 1518 // -- if the cv 1,j and cv 2,j are different, then const is in 1519 // every cv for 0 < k < j. 1520 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1521 && !PreviousToQualsIncludeConst) 1522 return false; 1523 1524 // Keep track of whether all prior cv-qualifiers in the "to" type 1525 // include const. 1526 PreviousToQualsIncludeConst 1527 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1528 } 1529 1530 // We are left with FromType and ToType being the pointee types 1531 // after unwrapping the original FromType and ToType the same number 1532 // of types. If we unwrapped any pointers, and if FromType and 1533 // ToType have the same unqualified type (since we checked 1534 // qualifiers above), then this is a qualification conversion. 1535 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); 1536} 1537 1538/// Determines whether there is a user-defined conversion sequence 1539/// (C++ [over.ics.user]) that converts expression From to the type 1540/// ToType. If such a conversion exists, User will contain the 1541/// user-defined conversion sequence that performs such a conversion 1542/// and this routine will return true. Otherwise, this routine returns 1543/// false and User is unspecified. 1544/// 1545/// \param AllowExplicit true if the conversion should consider C++0x 1546/// "explicit" conversion functions as well as non-explicit conversion 1547/// functions (C++0x [class.conv.fct]p2). 1548OverloadingResult Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1549 UserDefinedConversionSequence& User, 1550 OverloadCandidateSet& CandidateSet, 1551 bool AllowExplicit) { 1552 // Whether we will only visit constructors. 1553 bool ConstructorsOnly = false; 1554 1555 // If the type we are conversion to is a class type, enumerate its 1556 // constructors. 1557 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { 1558 // C++ [over.match.ctor]p1: 1559 // When objects of class type are direct-initialized (8.5), or 1560 // copy-initialized from an expression of the same or a 1561 // derived class type (8.5), overload resolution selects the 1562 // constructor. [...] For copy-initialization, the candidate 1563 // functions are all the converting constructors (12.3.1) of 1564 // that class. The argument list is the expression-list within 1565 // the parentheses of the initializer. 1566 if (Context.hasSameUnqualifiedType(ToType, From->getType()) || 1567 (From->getType()->getAs<RecordType>() && 1568 IsDerivedFrom(From->getType(), ToType))) 1569 ConstructorsOnly = true; 1570 1571 if (RequireCompleteType(From->getLocStart(), ToType, PDiag())) { 1572 // We're not going to find any constructors. 1573 } else if (CXXRecordDecl *ToRecordDecl 1574 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1575 DeclarationName ConstructorName 1576 = Context.DeclarationNames.getCXXConstructorName( 1577 Context.getCanonicalType(ToType).getUnqualifiedType()); 1578 DeclContext::lookup_iterator Con, ConEnd; 1579 for (llvm::tie(Con, ConEnd) 1580 = ToRecordDecl->lookup(ConstructorName); 1581 Con != ConEnd; ++Con) { 1582 NamedDecl *D = *Con; 1583 DeclAccessPair FoundDecl = DeclAccessPair::make(D, D->getAccess()); 1584 1585 // Find the constructor (which may be a template). 1586 CXXConstructorDecl *Constructor = 0; 1587 FunctionTemplateDecl *ConstructorTmpl 1588 = dyn_cast<FunctionTemplateDecl>(D); 1589 if (ConstructorTmpl) 1590 Constructor 1591 = cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl()); 1592 else 1593 Constructor = cast<CXXConstructorDecl>(D); 1594 1595 if (!Constructor->isInvalidDecl() && 1596 Constructor->isConvertingConstructor(AllowExplicit)) { 1597 if (ConstructorTmpl) 1598 AddTemplateOverloadCandidate(ConstructorTmpl, FoundDecl, 1599 /*ExplicitArgs*/ 0, 1600 &From, 1, CandidateSet, 1601 /*SuppressUserConversions=*/!ConstructorsOnly); 1602 else 1603 // Allow one user-defined conversion when user specifies a 1604 // From->ToType conversion via an static cast (c-style, etc). 1605 AddOverloadCandidate(Constructor, FoundDecl, 1606 &From, 1, CandidateSet, 1607 /*SuppressUserConversions=*/!ConstructorsOnly); 1608 } 1609 } 1610 } 1611 } 1612 1613 // Enumerate conversion functions, if we're allowed to. 1614 if (ConstructorsOnly) { 1615 } else if (RequireCompleteType(From->getLocStart(), From->getType(), 1616 PDiag(0) << From->getSourceRange())) { 1617 // No conversion functions from incomplete types. 1618 } else if (const RecordType *FromRecordType 1619 = From->getType()->getAs<RecordType>()) { 1620 if (CXXRecordDecl *FromRecordDecl 1621 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1622 // Add all of the conversion functions as candidates. 1623 const UnresolvedSetImpl *Conversions 1624 = FromRecordDecl->getVisibleConversionFunctions(); 1625 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 1626 E = Conversions->end(); I != E; ++I) { 1627 DeclAccessPair FoundDecl = I.getPair(); 1628 NamedDecl *D = FoundDecl.getDecl(); 1629 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 1630 if (isa<UsingShadowDecl>(D)) 1631 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 1632 1633 CXXConversionDecl *Conv; 1634 FunctionTemplateDecl *ConvTemplate; 1635 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) 1636 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 1637 else 1638 Conv = cast<CXXConversionDecl>(D); 1639 1640 if (AllowExplicit || !Conv->isExplicit()) { 1641 if (ConvTemplate) 1642 AddTemplateConversionCandidate(ConvTemplate, FoundDecl, 1643 ActingContext, From, ToType, 1644 CandidateSet); 1645 else 1646 AddConversionCandidate(Conv, FoundDecl, ActingContext, 1647 From, ToType, CandidateSet); 1648 } 1649 } 1650 } 1651 } 1652 1653 OverloadCandidateSet::iterator Best; 1654 switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) { 1655 case OR_Success: 1656 // Record the standard conversion we used and the conversion function. 1657 if (CXXConstructorDecl *Constructor 1658 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1659 // C++ [over.ics.user]p1: 1660 // If the user-defined conversion is specified by a 1661 // constructor (12.3.1), the initial standard conversion 1662 // sequence converts the source type to the type required by 1663 // the argument of the constructor. 1664 // 1665 QualType ThisType = Constructor->getThisType(Context); 1666 if (Best->Conversions[0].isEllipsis()) 1667 User.EllipsisConversion = true; 1668 else { 1669 User.Before = Best->Conversions[0].Standard; 1670 User.EllipsisConversion = false; 1671 } 1672 User.ConversionFunction = Constructor; 1673 User.After.setAsIdentityConversion(); 1674 User.After.setFromType( 1675 ThisType->getAs<PointerType>()->getPointeeType()); 1676 User.After.setAllToTypes(ToType); 1677 return OR_Success; 1678 } else if (CXXConversionDecl *Conversion 1679 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1680 // C++ [over.ics.user]p1: 1681 // 1682 // [...] If the user-defined conversion is specified by a 1683 // conversion function (12.3.2), the initial standard 1684 // conversion sequence converts the source type to the 1685 // implicit object parameter of the conversion function. 1686 User.Before = Best->Conversions[0].Standard; 1687 User.ConversionFunction = Conversion; 1688 User.EllipsisConversion = false; 1689 1690 // C++ [over.ics.user]p2: 1691 // The second standard conversion sequence converts the 1692 // result of the user-defined conversion to the target type 1693 // for the sequence. Since an implicit conversion sequence 1694 // is an initialization, the special rules for 1695 // initialization by user-defined conversion apply when 1696 // selecting the best user-defined conversion for a 1697 // user-defined conversion sequence (see 13.3.3 and 1698 // 13.3.3.1). 1699 User.After = Best->FinalConversion; 1700 return OR_Success; 1701 } else { 1702 assert(false && "Not a constructor or conversion function?"); 1703 return OR_No_Viable_Function; 1704 } 1705 1706 case OR_No_Viable_Function: 1707 return OR_No_Viable_Function; 1708 case OR_Deleted: 1709 // No conversion here! We're done. 1710 return OR_Deleted; 1711 1712 case OR_Ambiguous: 1713 return OR_Ambiguous; 1714 } 1715 1716 return OR_No_Viable_Function; 1717} 1718 1719bool 1720Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { 1721 ImplicitConversionSequence ICS; 1722 OverloadCandidateSet CandidateSet(From->getExprLoc()); 1723 OverloadingResult OvResult = 1724 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 1725 CandidateSet, false); 1726 if (OvResult == OR_Ambiguous) 1727 Diag(From->getSourceRange().getBegin(), 1728 diag::err_typecheck_ambiguous_condition) 1729 << From->getType() << ToType << From->getSourceRange(); 1730 else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) 1731 Diag(From->getSourceRange().getBegin(), 1732 diag::err_typecheck_nonviable_condition) 1733 << From->getType() << ToType << From->getSourceRange(); 1734 else 1735 return false; 1736 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &From, 1); 1737 return true; 1738} 1739 1740/// CompareImplicitConversionSequences - Compare two implicit 1741/// conversion sequences to determine whether one is better than the 1742/// other or if they are indistinguishable (C++ 13.3.3.2). 1743ImplicitConversionSequence::CompareKind 1744Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1745 const ImplicitConversionSequence& ICS2) 1746{ 1747 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1748 // conversion sequences (as defined in 13.3.3.1) 1749 // -- a standard conversion sequence (13.3.3.1.1) is a better 1750 // conversion sequence than a user-defined conversion sequence or 1751 // an ellipsis conversion sequence, and 1752 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1753 // conversion sequence than an ellipsis conversion sequence 1754 // (13.3.3.1.3). 1755 // 1756 // C++0x [over.best.ics]p10: 1757 // For the purpose of ranking implicit conversion sequences as 1758 // described in 13.3.3.2, the ambiguous conversion sequence is 1759 // treated as a user-defined sequence that is indistinguishable 1760 // from any other user-defined conversion sequence. 1761 if (ICS1.getKindRank() < ICS2.getKindRank()) 1762 return ImplicitConversionSequence::Better; 1763 else if (ICS2.getKindRank() < ICS1.getKindRank()) 1764 return ImplicitConversionSequence::Worse; 1765 1766 // Two implicit conversion sequences of the same form are 1767 // indistinguishable conversion sequences unless one of the 1768 // following rules apply: (C++ 13.3.3.2p3): 1769 if (ICS1.isStandard()) 1770 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1771 else if (ICS1.isUserDefined()) { 1772 // User-defined conversion sequence U1 is a better conversion 1773 // sequence than another user-defined conversion sequence U2 if 1774 // they contain the same user-defined conversion function or 1775 // constructor and if the second standard conversion sequence of 1776 // U1 is better than the second standard conversion sequence of 1777 // U2 (C++ 13.3.3.2p3). 1778 if (ICS1.UserDefined.ConversionFunction == 1779 ICS2.UserDefined.ConversionFunction) 1780 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1781 ICS2.UserDefined.After); 1782 } 1783 1784 return ImplicitConversionSequence::Indistinguishable; 1785} 1786 1787// Per 13.3.3.2p3, compare the given standard conversion sequences to 1788// determine if one is a proper subset of the other. 1789static ImplicitConversionSequence::CompareKind 1790compareStandardConversionSubsets(ASTContext &Context, 1791 const StandardConversionSequence& SCS1, 1792 const StandardConversionSequence& SCS2) { 1793 ImplicitConversionSequence::CompareKind Result 1794 = ImplicitConversionSequence::Indistinguishable; 1795 1796 if (SCS1.Second != SCS2.Second) { 1797 if (SCS1.Second == ICK_Identity) 1798 Result = ImplicitConversionSequence::Better; 1799 else if (SCS2.Second == ICK_Identity) 1800 Result = ImplicitConversionSequence::Worse; 1801 else 1802 return ImplicitConversionSequence::Indistinguishable; 1803 } else if (!Context.hasSameType(SCS1.getToType(1), SCS2.getToType(1))) 1804 return ImplicitConversionSequence::Indistinguishable; 1805 1806 if (SCS1.Third == SCS2.Third) { 1807 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result 1808 : ImplicitConversionSequence::Indistinguishable; 1809 } 1810 1811 if (SCS1.Third == ICK_Identity) 1812 return Result == ImplicitConversionSequence::Worse 1813 ? ImplicitConversionSequence::Indistinguishable 1814 : ImplicitConversionSequence::Better; 1815 1816 if (SCS2.Third == ICK_Identity) 1817 return Result == ImplicitConversionSequence::Better 1818 ? ImplicitConversionSequence::Indistinguishable 1819 : ImplicitConversionSequence::Worse; 1820 1821 return ImplicitConversionSequence::Indistinguishable; 1822} 1823 1824/// CompareStandardConversionSequences - Compare two standard 1825/// conversion sequences to determine whether one is better than the 1826/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1827ImplicitConversionSequence::CompareKind 1828Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1829 const StandardConversionSequence& SCS2) 1830{ 1831 // Standard conversion sequence S1 is a better conversion sequence 1832 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1833 1834 // -- S1 is a proper subsequence of S2 (comparing the conversion 1835 // sequences in the canonical form defined by 13.3.3.1.1, 1836 // excluding any Lvalue Transformation; the identity conversion 1837 // sequence is considered to be a subsequence of any 1838 // non-identity conversion sequence) or, if not that, 1839 if (ImplicitConversionSequence::CompareKind CK 1840 = compareStandardConversionSubsets(Context, SCS1, SCS2)) 1841 return CK; 1842 1843 // -- the rank of S1 is better than the rank of S2 (by the rules 1844 // defined below), or, if not that, 1845 ImplicitConversionRank Rank1 = SCS1.getRank(); 1846 ImplicitConversionRank Rank2 = SCS2.getRank(); 1847 if (Rank1 < Rank2) 1848 return ImplicitConversionSequence::Better; 1849 else if (Rank2 < Rank1) 1850 return ImplicitConversionSequence::Worse; 1851 1852 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1853 // are indistinguishable unless one of the following rules 1854 // applies: 1855 1856 // A conversion that is not a conversion of a pointer, or 1857 // pointer to member, to bool is better than another conversion 1858 // that is such a conversion. 1859 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1860 return SCS2.isPointerConversionToBool() 1861 ? ImplicitConversionSequence::Better 1862 : ImplicitConversionSequence::Worse; 1863 1864 // C++ [over.ics.rank]p4b2: 1865 // 1866 // If class B is derived directly or indirectly from class A, 1867 // conversion of B* to A* is better than conversion of B* to 1868 // void*, and conversion of A* to void* is better than conversion 1869 // of B* to void*. 1870 bool SCS1ConvertsToVoid 1871 = SCS1.isPointerConversionToVoidPointer(Context); 1872 bool SCS2ConvertsToVoid 1873 = SCS2.isPointerConversionToVoidPointer(Context); 1874 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1875 // Exactly one of the conversion sequences is a conversion to 1876 // a void pointer; it's the worse conversion. 1877 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1878 : ImplicitConversionSequence::Worse; 1879 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1880 // Neither conversion sequence converts to a void pointer; compare 1881 // their derived-to-base conversions. 1882 if (ImplicitConversionSequence::CompareKind DerivedCK 1883 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1884 return DerivedCK; 1885 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1886 // Both conversion sequences are conversions to void 1887 // pointers. Compare the source types to determine if there's an 1888 // inheritance relationship in their sources. 1889 QualType FromType1 = SCS1.getFromType(); 1890 QualType FromType2 = SCS2.getFromType(); 1891 1892 // Adjust the types we're converting from via the array-to-pointer 1893 // conversion, if we need to. 1894 if (SCS1.First == ICK_Array_To_Pointer) 1895 FromType1 = Context.getArrayDecayedType(FromType1); 1896 if (SCS2.First == ICK_Array_To_Pointer) 1897 FromType2 = Context.getArrayDecayedType(FromType2); 1898 1899 QualType FromPointee1 1900 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1901 QualType FromPointee2 1902 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1903 1904 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1905 return ImplicitConversionSequence::Better; 1906 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1907 return ImplicitConversionSequence::Worse; 1908 1909 // Objective-C++: If one interface is more specific than the 1910 // other, it is the better one. 1911 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 1912 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 1913 if (FromIface1 && FromIface1) { 1914 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1915 return ImplicitConversionSequence::Better; 1916 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1917 return ImplicitConversionSequence::Worse; 1918 } 1919 } 1920 1921 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1922 // bullet 3). 1923 if (ImplicitConversionSequence::CompareKind QualCK 1924 = CompareQualificationConversions(SCS1, SCS2)) 1925 return QualCK; 1926 1927 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1928 // C++0x [over.ics.rank]p3b4: 1929 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 1930 // implicit object parameter of a non-static member function declared 1931 // without a ref-qualifier, and S1 binds an rvalue reference to an 1932 // rvalue and S2 binds an lvalue reference. 1933 // FIXME: We don't know if we're dealing with the implicit object parameter, 1934 // or if the member function in this case has a ref qualifier. 1935 // (Of course, we don't have ref qualifiers yet.) 1936 if (SCS1.RRefBinding != SCS2.RRefBinding) 1937 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 1938 : ImplicitConversionSequence::Worse; 1939 1940 // C++ [over.ics.rank]p3b4: 1941 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1942 // which the references refer are the same type except for 1943 // top-level cv-qualifiers, and the type to which the reference 1944 // initialized by S2 refers is more cv-qualified than the type 1945 // to which the reference initialized by S1 refers. 1946 QualType T1 = SCS1.getToType(2); 1947 QualType T2 = SCS2.getToType(2); 1948 T1 = Context.getCanonicalType(T1); 1949 T2 = Context.getCanonicalType(T2); 1950 Qualifiers T1Quals, T2Quals; 1951 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1952 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1953 if (UnqualT1 == UnqualT2) { 1954 // If the type is an array type, promote the element qualifiers to the type 1955 // for comparison. 1956 if (isa<ArrayType>(T1) && T1Quals) 1957 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 1958 if (isa<ArrayType>(T2) && T2Quals) 1959 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 1960 if (T2.isMoreQualifiedThan(T1)) 1961 return ImplicitConversionSequence::Better; 1962 else if (T1.isMoreQualifiedThan(T2)) 1963 return ImplicitConversionSequence::Worse; 1964 } 1965 } 1966 1967 return ImplicitConversionSequence::Indistinguishable; 1968} 1969 1970/// CompareQualificationConversions - Compares two standard conversion 1971/// sequences to determine whether they can be ranked based on their 1972/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1973ImplicitConversionSequence::CompareKind 1974Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1975 const StandardConversionSequence& SCS2) { 1976 // C++ 13.3.3.2p3: 1977 // -- S1 and S2 differ only in their qualification conversion and 1978 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1979 // cv-qualification signature of type T1 is a proper subset of 1980 // the cv-qualification signature of type T2, and S1 is not the 1981 // deprecated string literal array-to-pointer conversion (4.2). 1982 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1983 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1984 return ImplicitConversionSequence::Indistinguishable; 1985 1986 // FIXME: the example in the standard doesn't use a qualification 1987 // conversion (!) 1988 QualType T1 = SCS1.getToType(2); 1989 QualType T2 = SCS2.getToType(2); 1990 T1 = Context.getCanonicalType(T1); 1991 T2 = Context.getCanonicalType(T2); 1992 Qualifiers T1Quals, T2Quals; 1993 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1994 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1995 1996 // If the types are the same, we won't learn anything by unwrapped 1997 // them. 1998 if (UnqualT1 == UnqualT2) 1999 return ImplicitConversionSequence::Indistinguishable; 2000 2001 // If the type is an array type, promote the element qualifiers to the type 2002 // for comparison. 2003 if (isa<ArrayType>(T1) && T1Quals) 2004 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2005 if (isa<ArrayType>(T2) && T2Quals) 2006 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2007 2008 ImplicitConversionSequence::CompareKind Result 2009 = ImplicitConversionSequence::Indistinguishable; 2010 while (UnwrapSimilarPointerTypes(T1, T2)) { 2011 // Within each iteration of the loop, we check the qualifiers to 2012 // determine if this still looks like a qualification 2013 // conversion. Then, if all is well, we unwrap one more level of 2014 // pointers or pointers-to-members and do it all again 2015 // until there are no more pointers or pointers-to-members left 2016 // to unwrap. This essentially mimics what 2017 // IsQualificationConversion does, but here we're checking for a 2018 // strict subset of qualifiers. 2019 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 2020 // The qualifiers are the same, so this doesn't tell us anything 2021 // about how the sequences rank. 2022 ; 2023 else if (T2.isMoreQualifiedThan(T1)) { 2024 // T1 has fewer qualifiers, so it could be the better sequence. 2025 if (Result == ImplicitConversionSequence::Worse) 2026 // Neither has qualifiers that are a subset of the other's 2027 // qualifiers. 2028 return ImplicitConversionSequence::Indistinguishable; 2029 2030 Result = ImplicitConversionSequence::Better; 2031 } else if (T1.isMoreQualifiedThan(T2)) { 2032 // T2 has fewer qualifiers, so it could be the better sequence. 2033 if (Result == ImplicitConversionSequence::Better) 2034 // Neither has qualifiers that are a subset of the other's 2035 // qualifiers. 2036 return ImplicitConversionSequence::Indistinguishable; 2037 2038 Result = ImplicitConversionSequence::Worse; 2039 } else { 2040 // Qualifiers are disjoint. 2041 return ImplicitConversionSequence::Indistinguishable; 2042 } 2043 2044 // If the types after this point are equivalent, we're done. 2045 if (Context.hasSameUnqualifiedType(T1, T2)) 2046 break; 2047 } 2048 2049 // Check that the winning standard conversion sequence isn't using 2050 // the deprecated string literal array to pointer conversion. 2051 switch (Result) { 2052 case ImplicitConversionSequence::Better: 2053 if (SCS1.DeprecatedStringLiteralToCharPtr) 2054 Result = ImplicitConversionSequence::Indistinguishable; 2055 break; 2056 2057 case ImplicitConversionSequence::Indistinguishable: 2058 break; 2059 2060 case ImplicitConversionSequence::Worse: 2061 if (SCS2.DeprecatedStringLiteralToCharPtr) 2062 Result = ImplicitConversionSequence::Indistinguishable; 2063 break; 2064 } 2065 2066 return Result; 2067} 2068 2069/// CompareDerivedToBaseConversions - Compares two standard conversion 2070/// sequences to determine whether they can be ranked based on their 2071/// various kinds of derived-to-base conversions (C++ 2072/// [over.ics.rank]p4b3). As part of these checks, we also look at 2073/// conversions between Objective-C interface types. 2074ImplicitConversionSequence::CompareKind 2075Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 2076 const StandardConversionSequence& SCS2) { 2077 QualType FromType1 = SCS1.getFromType(); 2078 QualType ToType1 = SCS1.getToType(1); 2079 QualType FromType2 = SCS2.getFromType(); 2080 QualType ToType2 = SCS2.getToType(1); 2081 2082 // Adjust the types we're converting from via the array-to-pointer 2083 // conversion, if we need to. 2084 if (SCS1.First == ICK_Array_To_Pointer) 2085 FromType1 = Context.getArrayDecayedType(FromType1); 2086 if (SCS2.First == ICK_Array_To_Pointer) 2087 FromType2 = Context.getArrayDecayedType(FromType2); 2088 2089 // Canonicalize all of the types. 2090 FromType1 = Context.getCanonicalType(FromType1); 2091 ToType1 = Context.getCanonicalType(ToType1); 2092 FromType2 = Context.getCanonicalType(FromType2); 2093 ToType2 = Context.getCanonicalType(ToType2); 2094 2095 // C++ [over.ics.rank]p4b3: 2096 // 2097 // If class B is derived directly or indirectly from class A and 2098 // class C is derived directly or indirectly from B, 2099 // 2100 // For Objective-C, we let A, B, and C also be Objective-C 2101 // interfaces. 2102 2103 // Compare based on pointer conversions. 2104 if (SCS1.Second == ICK_Pointer_Conversion && 2105 SCS2.Second == ICK_Pointer_Conversion && 2106 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 2107 FromType1->isPointerType() && FromType2->isPointerType() && 2108 ToType1->isPointerType() && ToType2->isPointerType()) { 2109 QualType FromPointee1 2110 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2111 QualType ToPointee1 2112 = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2113 QualType FromPointee2 2114 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2115 QualType ToPointee2 2116 = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2117 2118 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 2119 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 2120 const ObjCInterfaceType* ToIface1 = ToPointee1->getAs<ObjCInterfaceType>(); 2121 const ObjCInterfaceType* ToIface2 = ToPointee2->getAs<ObjCInterfaceType>(); 2122 2123 // -- conversion of C* to B* is better than conversion of C* to A*, 2124 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2125 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2126 return ImplicitConversionSequence::Better; 2127 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2128 return ImplicitConversionSequence::Worse; 2129 2130 if (ToIface1 && ToIface2) { 2131 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 2132 return ImplicitConversionSequence::Better; 2133 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 2134 return ImplicitConversionSequence::Worse; 2135 } 2136 } 2137 2138 // -- conversion of B* to A* is better than conversion of C* to A*, 2139 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 2140 if (IsDerivedFrom(FromPointee2, FromPointee1)) 2141 return ImplicitConversionSequence::Better; 2142 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 2143 return ImplicitConversionSequence::Worse; 2144 2145 if (FromIface1 && FromIface2) { 2146 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2147 return ImplicitConversionSequence::Better; 2148 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2149 return ImplicitConversionSequence::Worse; 2150 } 2151 } 2152 } 2153 2154 // Ranking of member-pointer types. 2155 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && 2156 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && 2157 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { 2158 const MemberPointerType * FromMemPointer1 = 2159 FromType1->getAs<MemberPointerType>(); 2160 const MemberPointerType * ToMemPointer1 = 2161 ToType1->getAs<MemberPointerType>(); 2162 const MemberPointerType * FromMemPointer2 = 2163 FromType2->getAs<MemberPointerType>(); 2164 const MemberPointerType * ToMemPointer2 = 2165 ToType2->getAs<MemberPointerType>(); 2166 const Type *FromPointeeType1 = FromMemPointer1->getClass(); 2167 const Type *ToPointeeType1 = ToMemPointer1->getClass(); 2168 const Type *FromPointeeType2 = FromMemPointer2->getClass(); 2169 const Type *ToPointeeType2 = ToMemPointer2->getClass(); 2170 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); 2171 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); 2172 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); 2173 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); 2174 // conversion of A::* to B::* is better than conversion of A::* to C::*, 2175 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2176 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2177 return ImplicitConversionSequence::Worse; 2178 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2179 return ImplicitConversionSequence::Better; 2180 } 2181 // conversion of B::* to C::* is better than conversion of A::* to C::* 2182 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { 2183 if (IsDerivedFrom(FromPointee1, FromPointee2)) 2184 return ImplicitConversionSequence::Better; 2185 else if (IsDerivedFrom(FromPointee2, FromPointee1)) 2186 return ImplicitConversionSequence::Worse; 2187 } 2188 } 2189 2190 if (SCS1.Second == ICK_Derived_To_Base) { 2191 // -- conversion of C to B is better than conversion of C to A, 2192 // -- binding of an expression of type C to a reference of type 2193 // B& is better than binding an expression of type C to a 2194 // reference of type A&, 2195 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2196 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2197 if (IsDerivedFrom(ToType1, ToType2)) 2198 return ImplicitConversionSequence::Better; 2199 else if (IsDerivedFrom(ToType2, ToType1)) 2200 return ImplicitConversionSequence::Worse; 2201 } 2202 2203 // -- conversion of B to A is better than conversion of C to A. 2204 // -- binding of an expression of type B to a reference of type 2205 // A& is better than binding an expression of type C to a 2206 // reference of type A&, 2207 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2208 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2209 if (IsDerivedFrom(FromType2, FromType1)) 2210 return ImplicitConversionSequence::Better; 2211 else if (IsDerivedFrom(FromType1, FromType2)) 2212 return ImplicitConversionSequence::Worse; 2213 } 2214 } 2215 2216 return ImplicitConversionSequence::Indistinguishable; 2217} 2218 2219/// CompareReferenceRelationship - Compare the two types T1 and T2 to 2220/// determine whether they are reference-related, 2221/// reference-compatible, reference-compatible with added 2222/// qualification, or incompatible, for use in C++ initialization by 2223/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 2224/// type, and the first type (T1) is the pointee type of the reference 2225/// type being initialized. 2226Sema::ReferenceCompareResult 2227Sema::CompareReferenceRelationship(SourceLocation Loc, 2228 QualType OrigT1, QualType OrigT2, 2229 bool& DerivedToBase) { 2230 assert(!OrigT1->isReferenceType() && 2231 "T1 must be the pointee type of the reference type"); 2232 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); 2233 2234 QualType T1 = Context.getCanonicalType(OrigT1); 2235 QualType T2 = Context.getCanonicalType(OrigT2); 2236 Qualifiers T1Quals, T2Quals; 2237 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2238 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2239 2240 // C++ [dcl.init.ref]p4: 2241 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is 2242 // reference-related to "cv2 T2" if T1 is the same type as T2, or 2243 // T1 is a base class of T2. 2244 if (UnqualT1 == UnqualT2) 2245 DerivedToBase = false; 2246 else if (!RequireCompleteType(Loc, OrigT1, PDiag()) && 2247 !RequireCompleteType(Loc, OrigT2, PDiag()) && 2248 IsDerivedFrom(UnqualT2, UnqualT1)) 2249 DerivedToBase = true; 2250 else 2251 return Ref_Incompatible; 2252 2253 // At this point, we know that T1 and T2 are reference-related (at 2254 // least). 2255 2256 // If the type is an array type, promote the element qualifiers to the type 2257 // for comparison. 2258 if (isa<ArrayType>(T1) && T1Quals) 2259 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2260 if (isa<ArrayType>(T2) && T2Quals) 2261 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2262 2263 // C++ [dcl.init.ref]p4: 2264 // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is 2265 // reference-related to T2 and cv1 is the same cv-qualification 2266 // as, or greater cv-qualification than, cv2. For purposes of 2267 // overload resolution, cases for which cv1 is greater 2268 // cv-qualification than cv2 are identified as 2269 // reference-compatible with added qualification (see 13.3.3.2). 2270 if (T1Quals.getCVRQualifiers() == T2Quals.getCVRQualifiers()) 2271 return Ref_Compatible; 2272 else if (T1.isMoreQualifiedThan(T2)) 2273 return Ref_Compatible_With_Added_Qualification; 2274 else 2275 return Ref_Related; 2276} 2277 2278/// \brief Compute an implicit conversion sequence for reference 2279/// initialization. 2280static ImplicitConversionSequence 2281TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType, 2282 SourceLocation DeclLoc, 2283 bool SuppressUserConversions, 2284 bool AllowExplicit) { 2285 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 2286 2287 // Most paths end in a failed conversion. 2288 ImplicitConversionSequence ICS; 2289 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); 2290 2291 QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType(); 2292 QualType T2 = Init->getType(); 2293 2294 // If the initializer is the address of an overloaded function, try 2295 // to resolve the overloaded function. If all goes well, T2 is the 2296 // type of the resulting function. 2297 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { 2298 DeclAccessPair Found; 2299 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, 2300 false, Found)) 2301 T2 = Fn->getType(); 2302 } 2303 2304 // Compute some basic properties of the types and the initializer. 2305 bool isRValRef = DeclType->isRValueReferenceType(); 2306 bool DerivedToBase = false; 2307 Expr::isLvalueResult InitLvalue = Init->isLvalue(S.Context); 2308 Sema::ReferenceCompareResult RefRelationship 2309 = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase); 2310 2311 // C++ [dcl.init.ref]p5: 2312 // A reference to type "cv1 T1" is initialized by an expression 2313 // of type "cv2 T2" as follows: 2314 2315 // -- If the initializer expression 2316 2317 // C++ [over.ics.ref]p3: 2318 // Except for an implicit object parameter, for which see 13.3.1, 2319 // a standard conversion sequence cannot be formed if it requires 2320 // binding an lvalue reference to non-const to an rvalue or 2321 // binding an rvalue reference to an lvalue. 2322 if (isRValRef && InitLvalue == Expr::LV_Valid) 2323 return ICS; 2324 2325 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is 2326 // reference-compatible with "cv2 T2," or 2327 // 2328 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. 2329 if (InitLvalue == Expr::LV_Valid && 2330 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2331 // C++ [over.ics.ref]p1: 2332 // When a parameter of reference type binds directly (8.5.3) 2333 // to an argument expression, the implicit conversion sequence 2334 // is the identity conversion, unless the argument expression 2335 // has a type that is a derived class of the parameter type, 2336 // in which case the implicit conversion sequence is a 2337 // derived-to-base Conversion (13.3.3.1). 2338 ICS.setStandard(); 2339 ICS.Standard.First = ICK_Identity; 2340 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2341 ICS.Standard.Third = ICK_Identity; 2342 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2343 ICS.Standard.setToType(0, T2); 2344 ICS.Standard.setToType(1, T1); 2345 ICS.Standard.setToType(2, T1); 2346 ICS.Standard.ReferenceBinding = true; 2347 ICS.Standard.DirectBinding = true; 2348 ICS.Standard.RRefBinding = false; 2349 ICS.Standard.CopyConstructor = 0; 2350 2351 // Nothing more to do: the inaccessibility/ambiguity check for 2352 // derived-to-base conversions is suppressed when we're 2353 // computing the implicit conversion sequence (C++ 2354 // [over.best.ics]p2). 2355 return ICS; 2356 } 2357 2358 // -- has a class type (i.e., T2 is a class type), where T1 is 2359 // not reference-related to T2, and can be implicitly 2360 // converted to an lvalue of type "cv3 T3," where "cv1 T1" 2361 // is reference-compatible with "cv3 T3" 92) (this 2362 // conversion is selected by enumerating the applicable 2363 // conversion functions (13.3.1.6) and choosing the best 2364 // one through overload resolution (13.3)), 2365 if (!isRValRef && !SuppressUserConversions && T2->isRecordType() && 2366 !S.RequireCompleteType(DeclLoc, T2, 0) && 2367 RefRelationship == Sema::Ref_Incompatible) { 2368 CXXRecordDecl *T2RecordDecl 2369 = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl()); 2370 2371 OverloadCandidateSet CandidateSet(DeclLoc); 2372 const UnresolvedSetImpl *Conversions 2373 = T2RecordDecl->getVisibleConversionFunctions(); 2374 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 2375 E = Conversions->end(); I != E; ++I) { 2376 NamedDecl *D = *I; 2377 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext()); 2378 if (isa<UsingShadowDecl>(D)) 2379 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 2380 2381 FunctionTemplateDecl *ConvTemplate 2382 = dyn_cast<FunctionTemplateDecl>(D); 2383 CXXConversionDecl *Conv; 2384 if (ConvTemplate) 2385 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 2386 else 2387 Conv = cast<CXXConversionDecl>(D); 2388 2389 // If the conversion function doesn't return a reference type, 2390 // it can't be considered for this conversion. 2391 if (Conv->getConversionType()->isLValueReferenceType() && 2392 (AllowExplicit || !Conv->isExplicit())) { 2393 if (ConvTemplate) 2394 S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC, 2395 Init, DeclType, CandidateSet); 2396 else 2397 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init, 2398 DeclType, CandidateSet); 2399 } 2400 } 2401 2402 OverloadCandidateSet::iterator Best; 2403 switch (S.BestViableFunction(CandidateSet, DeclLoc, Best)) { 2404 case OR_Success: 2405 // C++ [over.ics.ref]p1: 2406 // 2407 // [...] If the parameter binds directly to the result of 2408 // applying a conversion function to the argument 2409 // expression, the implicit conversion sequence is a 2410 // user-defined conversion sequence (13.3.3.1.2), with the 2411 // second standard conversion sequence either an identity 2412 // conversion or, if the conversion function returns an 2413 // entity of a type that is a derived class of the parameter 2414 // type, a derived-to-base Conversion. 2415 if (!Best->FinalConversion.DirectBinding) 2416 break; 2417 2418 ICS.setUserDefined(); 2419 ICS.UserDefined.Before = Best->Conversions[0].Standard; 2420 ICS.UserDefined.After = Best->FinalConversion; 2421 ICS.UserDefined.ConversionFunction = Best->Function; 2422 ICS.UserDefined.EllipsisConversion = false; 2423 assert(ICS.UserDefined.After.ReferenceBinding && 2424 ICS.UserDefined.After.DirectBinding && 2425 "Expected a direct reference binding!"); 2426 return ICS; 2427 2428 case OR_Ambiguous: 2429 ICS.setAmbiguous(); 2430 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 2431 Cand != CandidateSet.end(); ++Cand) 2432 if (Cand->Viable) 2433 ICS.Ambiguous.addConversion(Cand->Function); 2434 return ICS; 2435 2436 case OR_No_Viable_Function: 2437 case OR_Deleted: 2438 // There was no suitable conversion, or we found a deleted 2439 // conversion; continue with other checks. 2440 break; 2441 } 2442 } 2443 2444 // -- Otherwise, the reference shall be to a non-volatile const 2445 // type (i.e., cv1 shall be const), or the reference shall be an 2446 // rvalue reference and the initializer expression shall be an rvalue. 2447 if (!isRValRef && T1.getCVRQualifiers() != Qualifiers::Const) 2448 return ICS; 2449 2450 // -- if T2 is a class type and 2451 // -- the initializer expression is an rvalue and "cv1 T1" 2452 // is reference-compatible with "cv2 T2," or 2453 // 2454 // -- T1 is not reference-related to T2 and the initializer 2455 // expression can be implicitly converted to an rvalue 2456 // of type "cv3 T3" (this conversion is selected by 2457 // enumerating the applicable conversion functions 2458 // (13.3.1.6) and choosing the best one through overload 2459 // resolution (13.3)), 2460 // 2461 // then the reference is bound to the initializer 2462 // expression rvalue in the first case and to the object 2463 // that is the result of the conversion in the second case 2464 // (or, in either case, to the appropriate base class 2465 // subobject of the object). 2466 // 2467 // We're only checking the first case here, which is a direct 2468 // binding in C++0x but not in C++03. 2469 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 2470 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2471 ICS.setStandard(); 2472 ICS.Standard.First = ICK_Identity; 2473 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2474 ICS.Standard.Third = ICK_Identity; 2475 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2476 ICS.Standard.setToType(0, T2); 2477 ICS.Standard.setToType(1, T1); 2478 ICS.Standard.setToType(2, T1); 2479 ICS.Standard.ReferenceBinding = true; 2480 ICS.Standard.DirectBinding = S.getLangOptions().CPlusPlus0x; 2481 ICS.Standard.RRefBinding = isRValRef; 2482 ICS.Standard.CopyConstructor = 0; 2483 return ICS; 2484 } 2485 2486 // -- Otherwise, a temporary of type "cv1 T1" is created and 2487 // initialized from the initializer expression using the 2488 // rules for a non-reference copy initialization (8.5). The 2489 // reference is then bound to the temporary. If T1 is 2490 // reference-related to T2, cv1 must be the same 2491 // cv-qualification as, or greater cv-qualification than, 2492 // cv2; otherwise, the program is ill-formed. 2493 if (RefRelationship == Sema::Ref_Related) { 2494 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 2495 // we would be reference-compatible or reference-compatible with 2496 // added qualification. But that wasn't the case, so the reference 2497 // initialization fails. 2498 return ICS; 2499 } 2500 2501 // If at least one of the types is a class type, the types are not 2502 // related, and we aren't allowed any user conversions, the 2503 // reference binding fails. This case is important for breaking 2504 // recursion, since TryImplicitConversion below will attempt to 2505 // create a temporary through the use of a copy constructor. 2506 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && 2507 (T1->isRecordType() || T2->isRecordType())) 2508 return ICS; 2509 2510 // C++ [over.ics.ref]p2: 2511 // 2512 // When a parameter of reference type is not bound directly to 2513 // an argument expression, the conversion sequence is the one 2514 // required to convert the argument expression to the 2515 // underlying type of the reference according to 2516 // 13.3.3.1. Conceptually, this conversion sequence corresponds 2517 // to copy-initializing a temporary of the underlying type with 2518 // the argument expression. Any difference in top-level 2519 // cv-qualification is subsumed by the initialization itself 2520 // and does not constitute a conversion. 2521 ICS = S.TryImplicitConversion(Init, T1, SuppressUserConversions, 2522 /*AllowExplicit=*/false, 2523 /*InOverloadResolution=*/false); 2524 2525 // Of course, that's still a reference binding. 2526 if (ICS.isStandard()) { 2527 ICS.Standard.ReferenceBinding = true; 2528 ICS.Standard.RRefBinding = isRValRef; 2529 } else if (ICS.isUserDefined()) { 2530 ICS.UserDefined.After.ReferenceBinding = true; 2531 ICS.UserDefined.After.RRefBinding = isRValRef; 2532 } 2533 return ICS; 2534} 2535 2536/// TryCopyInitialization - Try to copy-initialize a value of type 2537/// ToType from the expression From. Return the implicit conversion 2538/// sequence required to pass this argument, which may be a bad 2539/// conversion sequence (meaning that the argument cannot be passed to 2540/// a parameter of this type). If @p SuppressUserConversions, then we 2541/// do not permit any user-defined conversion sequences. 2542static ImplicitConversionSequence 2543TryCopyInitialization(Sema &S, Expr *From, QualType ToType, 2544 bool SuppressUserConversions, 2545 bool InOverloadResolution) { 2546 if (ToType->isReferenceType()) 2547 return TryReferenceInit(S, From, ToType, 2548 /*FIXME:*/From->getLocStart(), 2549 SuppressUserConversions, 2550 /*AllowExplicit=*/false); 2551 2552 return S.TryImplicitConversion(From, ToType, 2553 SuppressUserConversions, 2554 /*AllowExplicit=*/false, 2555 InOverloadResolution); 2556} 2557 2558/// TryObjectArgumentInitialization - Try to initialize the object 2559/// parameter of the given member function (@c Method) from the 2560/// expression @p From. 2561ImplicitConversionSequence 2562Sema::TryObjectArgumentInitialization(QualType OrigFromType, 2563 CXXMethodDecl *Method, 2564 CXXRecordDecl *ActingContext) { 2565 QualType ClassType = Context.getTypeDeclType(ActingContext); 2566 // [class.dtor]p2: A destructor can be invoked for a const, volatile or 2567 // const volatile object. 2568 unsigned Quals = isa<CXXDestructorDecl>(Method) ? 2569 Qualifiers::Const | Qualifiers::Volatile : Method->getTypeQualifiers(); 2570 QualType ImplicitParamType = Context.getCVRQualifiedType(ClassType, Quals); 2571 2572 // Set up the conversion sequence as a "bad" conversion, to allow us 2573 // to exit early. 2574 ImplicitConversionSequence ICS; 2575 2576 // We need to have an object of class type. 2577 QualType FromType = OrigFromType; 2578 if (const PointerType *PT = FromType->getAs<PointerType>()) 2579 FromType = PT->getPointeeType(); 2580 2581 assert(FromType->isRecordType()); 2582 2583 // The implicit object parameter is has the type "reference to cv X", 2584 // where X is the class of which the function is a member 2585 // (C++ [over.match.funcs]p4). However, when finding an implicit 2586 // conversion sequence for the argument, we are not allowed to 2587 // create temporaries or perform user-defined conversions 2588 // (C++ [over.match.funcs]p5). We perform a simplified version of 2589 // reference binding here, that allows class rvalues to bind to 2590 // non-constant references. 2591 2592 // First check the qualifiers. We don't care about lvalue-vs-rvalue 2593 // with the implicit object parameter (C++ [over.match.funcs]p5). 2594 QualType FromTypeCanon = Context.getCanonicalType(FromType); 2595 if (ImplicitParamType.getCVRQualifiers() 2596 != FromTypeCanon.getLocalCVRQualifiers() && 2597 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { 2598 ICS.setBad(BadConversionSequence::bad_qualifiers, 2599 OrigFromType, ImplicitParamType); 2600 return ICS; 2601 } 2602 2603 // Check that we have either the same type or a derived type. It 2604 // affects the conversion rank. 2605 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 2606 ImplicitConversionKind SecondKind; 2607 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { 2608 SecondKind = ICK_Identity; 2609 } else if (IsDerivedFrom(FromType, ClassType)) 2610 SecondKind = ICK_Derived_To_Base; 2611 else { 2612 ICS.setBad(BadConversionSequence::unrelated_class, 2613 FromType, ImplicitParamType); 2614 return ICS; 2615 } 2616 2617 // Success. Mark this as a reference binding. 2618 ICS.setStandard(); 2619 ICS.Standard.setAsIdentityConversion(); 2620 ICS.Standard.Second = SecondKind; 2621 ICS.Standard.setFromType(FromType); 2622 ICS.Standard.setAllToTypes(ImplicitParamType); 2623 ICS.Standard.ReferenceBinding = true; 2624 ICS.Standard.DirectBinding = true; 2625 ICS.Standard.RRefBinding = false; 2626 return ICS; 2627} 2628 2629/// PerformObjectArgumentInitialization - Perform initialization of 2630/// the implicit object parameter for the given Method with the given 2631/// expression. 2632bool 2633Sema::PerformObjectArgumentInitialization(Expr *&From, 2634 NestedNameSpecifier *Qualifier, 2635 NamedDecl *FoundDecl, 2636 CXXMethodDecl *Method) { 2637 QualType FromRecordType, DestType; 2638 QualType ImplicitParamRecordType = 2639 Method->getThisType(Context)->getAs<PointerType>()->getPointeeType(); 2640 2641 if (const PointerType *PT = From->getType()->getAs<PointerType>()) { 2642 FromRecordType = PT->getPointeeType(); 2643 DestType = Method->getThisType(Context); 2644 } else { 2645 FromRecordType = From->getType(); 2646 DestType = ImplicitParamRecordType; 2647 } 2648 2649 // Note that we always use the true parent context when performing 2650 // the actual argument initialization. 2651 ImplicitConversionSequence ICS 2652 = TryObjectArgumentInitialization(From->getType(), Method, 2653 Method->getParent()); 2654 if (ICS.isBad()) 2655 return Diag(From->getSourceRange().getBegin(), 2656 diag::err_implicit_object_parameter_init) 2657 << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); 2658 2659 if (ICS.Standard.Second == ICK_Derived_To_Base) 2660 return PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); 2661 2662 if (!Context.hasSameType(From->getType(), DestType)) 2663 ImpCastExprToType(From, DestType, CastExpr::CK_NoOp, 2664 /*isLvalue=*/!From->getType()->getAs<PointerType>()); 2665 return false; 2666} 2667 2668/// TryContextuallyConvertToBool - Attempt to contextually convert the 2669/// expression From to bool (C++0x [conv]p3). 2670ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 2671 return TryImplicitConversion(From, Context.BoolTy, 2672 // FIXME: Are these flags correct? 2673 /*SuppressUserConversions=*/false, 2674 /*AllowExplicit=*/true, 2675 /*InOverloadResolution=*/false); 2676} 2677 2678/// PerformContextuallyConvertToBool - Perform a contextual conversion 2679/// of the expression From to bool (C++0x [conv]p3). 2680bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2681 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2682 if (!ICS.isBad()) 2683 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); 2684 2685 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2686 return Diag(From->getSourceRange().getBegin(), 2687 diag::err_typecheck_bool_condition) 2688 << From->getType() << From->getSourceRange(); 2689 return true; 2690} 2691 2692/// AddOverloadCandidate - Adds the given function to the set of 2693/// candidate functions, using the given function call arguments. If 2694/// @p SuppressUserConversions, then don't allow user-defined 2695/// conversions via constructors or conversion operators. 2696/// 2697/// \para PartialOverloading true if we are performing "partial" overloading 2698/// based on an incomplete set of function arguments. This feature is used by 2699/// code completion. 2700void 2701Sema::AddOverloadCandidate(FunctionDecl *Function, 2702 DeclAccessPair FoundDecl, 2703 Expr **Args, unsigned NumArgs, 2704 OverloadCandidateSet& CandidateSet, 2705 bool SuppressUserConversions, 2706 bool PartialOverloading) { 2707 const FunctionProtoType* Proto 2708 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2709 assert(Proto && "Functions without a prototype cannot be overloaded"); 2710 assert(!Function->getDescribedFunctionTemplate() && 2711 "Use AddTemplateOverloadCandidate for function templates"); 2712 2713 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2714 if (!isa<CXXConstructorDecl>(Method)) { 2715 // If we get here, it's because we're calling a member function 2716 // that is named without a member access expression (e.g., 2717 // "this->f") that was either written explicitly or created 2718 // implicitly. This can happen with a qualified call to a member 2719 // function, e.g., X::f(). We use an empty type for the implied 2720 // object argument (C++ [over.call.func]p3), and the acting context 2721 // is irrelevant. 2722 AddMethodCandidate(Method, FoundDecl, Method->getParent(), 2723 QualType(), Args, NumArgs, CandidateSet, 2724 SuppressUserConversions); 2725 return; 2726 } 2727 // We treat a constructor like a non-member function, since its object 2728 // argument doesn't participate in overload resolution. 2729 } 2730 2731 if (!CandidateSet.isNewCandidate(Function)) 2732 return; 2733 2734 // Overload resolution is always an unevaluated context. 2735 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2736 2737 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2738 // C++ [class.copy]p3: 2739 // A member function template is never instantiated to perform the copy 2740 // of a class object to an object of its class type. 2741 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2742 if (NumArgs == 1 && 2743 Constructor->isCopyConstructorLikeSpecialization() && 2744 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || 2745 IsDerivedFrom(Args[0]->getType(), ClassType))) 2746 return; 2747 } 2748 2749 // Add this candidate 2750 CandidateSet.push_back(OverloadCandidate()); 2751 OverloadCandidate& Candidate = CandidateSet.back(); 2752 Candidate.FoundDecl = FoundDecl; 2753 Candidate.Function = Function; 2754 Candidate.Viable = true; 2755 Candidate.IsSurrogate = false; 2756 Candidate.IgnoreObjectArgument = false; 2757 2758 unsigned NumArgsInProto = Proto->getNumArgs(); 2759 2760 // (C++ 13.3.2p2): A candidate function having fewer than m 2761 // parameters is viable only if it has an ellipsis in its parameter 2762 // list (8.3.5). 2763 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 2764 !Proto->isVariadic()) { 2765 Candidate.Viable = false; 2766 Candidate.FailureKind = ovl_fail_too_many_arguments; 2767 return; 2768 } 2769 2770 // (C++ 13.3.2p2): A candidate function having more than m parameters 2771 // is viable only if the (m+1)st parameter has a default argument 2772 // (8.3.6). For the purposes of overload resolution, the 2773 // parameter list is truncated on the right, so that there are 2774 // exactly m parameters. 2775 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2776 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 2777 // Not enough arguments. 2778 Candidate.Viable = false; 2779 Candidate.FailureKind = ovl_fail_too_few_arguments; 2780 return; 2781 } 2782 2783 // Determine the implicit conversion sequences for each of the 2784 // arguments. 2785 Candidate.Conversions.resize(NumArgs); 2786 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2787 if (ArgIdx < NumArgsInProto) { 2788 // (C++ 13.3.2p3): for F to be a viable function, there shall 2789 // exist for each argument an implicit conversion sequence 2790 // (13.3.3.1) that converts that argument to the corresponding 2791 // parameter of F. 2792 QualType ParamType = Proto->getArgType(ArgIdx); 2793 Candidate.Conversions[ArgIdx] 2794 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 2795 SuppressUserConversions, 2796 /*InOverloadResolution=*/true); 2797 if (Candidate.Conversions[ArgIdx].isBad()) { 2798 Candidate.Viable = false; 2799 Candidate.FailureKind = ovl_fail_bad_conversion; 2800 break; 2801 } 2802 } else { 2803 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2804 // argument for which there is no corresponding parameter is 2805 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2806 Candidate.Conversions[ArgIdx].setEllipsis(); 2807 } 2808 } 2809} 2810 2811/// \brief Add all of the function declarations in the given function set to 2812/// the overload canddiate set. 2813void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, 2814 Expr **Args, unsigned NumArgs, 2815 OverloadCandidateSet& CandidateSet, 2816 bool SuppressUserConversions) { 2817 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { 2818 NamedDecl *D = F.getDecl()->getUnderlyingDecl(); 2819 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 2820 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 2821 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), 2822 cast<CXXMethodDecl>(FD)->getParent(), 2823 Args[0]->getType(), Args + 1, NumArgs - 1, 2824 CandidateSet, SuppressUserConversions); 2825 else 2826 AddOverloadCandidate(FD, F.getPair(), Args, NumArgs, CandidateSet, 2827 SuppressUserConversions); 2828 } else { 2829 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D); 2830 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 2831 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 2832 AddMethodTemplateCandidate(FunTmpl, F.getPair(), 2833 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 2834 /*FIXME: explicit args */ 0, 2835 Args[0]->getType(), Args + 1, NumArgs - 1, 2836 CandidateSet, 2837 SuppressUserConversions); 2838 else 2839 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), 2840 /*FIXME: explicit args */ 0, 2841 Args, NumArgs, CandidateSet, 2842 SuppressUserConversions); 2843 } 2844 } 2845} 2846 2847/// AddMethodCandidate - Adds a named decl (which is some kind of 2848/// method) as a method candidate to the given overload set. 2849void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, 2850 QualType ObjectType, 2851 Expr **Args, unsigned NumArgs, 2852 OverloadCandidateSet& CandidateSet, 2853 bool SuppressUserConversions) { 2854 NamedDecl *Decl = FoundDecl.getDecl(); 2855 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 2856 2857 if (isa<UsingShadowDecl>(Decl)) 2858 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 2859 2860 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 2861 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 2862 "Expected a member function template"); 2863 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, 2864 /*ExplicitArgs*/ 0, 2865 ObjectType, Args, NumArgs, 2866 CandidateSet, 2867 SuppressUserConversions); 2868 } else { 2869 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, 2870 ObjectType, Args, NumArgs, 2871 CandidateSet, SuppressUserConversions); 2872 } 2873} 2874 2875/// AddMethodCandidate - Adds the given C++ member function to the set 2876/// of candidate functions, using the given function call arguments 2877/// and the object argument (@c Object). For example, in a call 2878/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2879/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2880/// allow user-defined conversions via constructors or conversion 2881/// operators. 2882void 2883Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, 2884 CXXRecordDecl *ActingContext, QualType ObjectType, 2885 Expr **Args, unsigned NumArgs, 2886 OverloadCandidateSet& CandidateSet, 2887 bool SuppressUserConversions) { 2888 const FunctionProtoType* Proto 2889 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 2890 assert(Proto && "Methods without a prototype cannot be overloaded"); 2891 assert(!isa<CXXConstructorDecl>(Method) && 2892 "Use AddOverloadCandidate for constructors"); 2893 2894 if (!CandidateSet.isNewCandidate(Method)) 2895 return; 2896 2897 // Overload resolution is always an unevaluated context. 2898 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2899 2900 // Add this candidate 2901 CandidateSet.push_back(OverloadCandidate()); 2902 OverloadCandidate& Candidate = CandidateSet.back(); 2903 Candidate.FoundDecl = FoundDecl; 2904 Candidate.Function = Method; 2905 Candidate.IsSurrogate = false; 2906 Candidate.IgnoreObjectArgument = false; 2907 2908 unsigned NumArgsInProto = Proto->getNumArgs(); 2909 2910 // (C++ 13.3.2p2): A candidate function having fewer than m 2911 // parameters is viable only if it has an ellipsis in its parameter 2912 // list (8.3.5). 2913 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2914 Candidate.Viable = false; 2915 Candidate.FailureKind = ovl_fail_too_many_arguments; 2916 return; 2917 } 2918 2919 // (C++ 13.3.2p2): A candidate function having more than m parameters 2920 // is viable only if the (m+1)st parameter has a default argument 2921 // (8.3.6). For the purposes of overload resolution, the 2922 // parameter list is truncated on the right, so that there are 2923 // exactly m parameters. 2924 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2925 if (NumArgs < MinRequiredArgs) { 2926 // Not enough arguments. 2927 Candidate.Viable = false; 2928 Candidate.FailureKind = ovl_fail_too_few_arguments; 2929 return; 2930 } 2931 2932 Candidate.Viable = true; 2933 Candidate.Conversions.resize(NumArgs + 1); 2934 2935 if (Method->isStatic() || ObjectType.isNull()) 2936 // The implicit object argument is ignored. 2937 Candidate.IgnoreObjectArgument = true; 2938 else { 2939 // Determine the implicit conversion sequence for the object 2940 // parameter. 2941 Candidate.Conversions[0] 2942 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 2943 if (Candidate.Conversions[0].isBad()) { 2944 Candidate.Viable = false; 2945 Candidate.FailureKind = ovl_fail_bad_conversion; 2946 return; 2947 } 2948 } 2949 2950 // Determine the implicit conversion sequences for each of the 2951 // arguments. 2952 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2953 if (ArgIdx < NumArgsInProto) { 2954 // (C++ 13.3.2p3): for F to be a viable function, there shall 2955 // exist for each argument an implicit conversion sequence 2956 // (13.3.3.1) that converts that argument to the corresponding 2957 // parameter of F. 2958 QualType ParamType = Proto->getArgType(ArgIdx); 2959 Candidate.Conversions[ArgIdx + 1] 2960 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 2961 SuppressUserConversions, 2962 /*InOverloadResolution=*/true); 2963 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 2964 Candidate.Viable = false; 2965 Candidate.FailureKind = ovl_fail_bad_conversion; 2966 break; 2967 } 2968 } else { 2969 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2970 // argument for which there is no corresponding parameter is 2971 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2972 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 2973 } 2974 } 2975} 2976 2977/// \brief Add a C++ member function template as a candidate to the candidate 2978/// set, using template argument deduction to produce an appropriate member 2979/// function template specialization. 2980void 2981Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 2982 DeclAccessPair FoundDecl, 2983 CXXRecordDecl *ActingContext, 2984 const TemplateArgumentListInfo *ExplicitTemplateArgs, 2985 QualType ObjectType, 2986 Expr **Args, unsigned NumArgs, 2987 OverloadCandidateSet& CandidateSet, 2988 bool SuppressUserConversions) { 2989 if (!CandidateSet.isNewCandidate(MethodTmpl)) 2990 return; 2991 2992 // C++ [over.match.funcs]p7: 2993 // In each case where a candidate is a function template, candidate 2994 // function template specializations are generated using template argument 2995 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 2996 // candidate functions in the usual way.113) A given name can refer to one 2997 // or more function templates and also to a set of overloaded non-template 2998 // functions. In such a case, the candidate functions generated from each 2999 // function template are combined with the set of non-template candidate 3000 // functions. 3001 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3002 FunctionDecl *Specialization = 0; 3003 if (TemplateDeductionResult Result 3004 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 3005 Args, NumArgs, Specialization, Info)) { 3006 // FIXME: Record what happened with template argument deduction, so 3007 // that we can give the user a beautiful diagnostic. 3008 (void)Result; 3009 return; 3010 } 3011 3012 // Add the function template specialization produced by template argument 3013 // deduction as a candidate. 3014 assert(Specialization && "Missing member function template specialization?"); 3015 assert(isa<CXXMethodDecl>(Specialization) && 3016 "Specialization is not a member function?"); 3017 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl, 3018 ActingContext, ObjectType, Args, NumArgs, 3019 CandidateSet, SuppressUserConversions); 3020} 3021 3022/// \brief Add a C++ function template specialization as a candidate 3023/// in the candidate set, using template argument deduction to produce 3024/// an appropriate function template specialization. 3025void 3026Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 3027 DeclAccessPair FoundDecl, 3028 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3029 Expr **Args, unsigned NumArgs, 3030 OverloadCandidateSet& CandidateSet, 3031 bool SuppressUserConversions) { 3032 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3033 return; 3034 3035 // C++ [over.match.funcs]p7: 3036 // In each case where a candidate is a function template, candidate 3037 // function template specializations are generated using template argument 3038 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3039 // candidate functions in the usual way.113) A given name can refer to one 3040 // or more function templates and also to a set of overloaded non-template 3041 // functions. In such a case, the candidate functions generated from each 3042 // function template are combined with the set of non-template candidate 3043 // functions. 3044 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3045 FunctionDecl *Specialization = 0; 3046 if (TemplateDeductionResult Result 3047 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3048 Args, NumArgs, Specialization, Info)) { 3049 CandidateSet.push_back(OverloadCandidate()); 3050 OverloadCandidate &Candidate = CandidateSet.back(); 3051 Candidate.FoundDecl = FoundDecl; 3052 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3053 Candidate.Viable = false; 3054 Candidate.FailureKind = ovl_fail_bad_deduction; 3055 Candidate.IsSurrogate = false; 3056 Candidate.IgnoreObjectArgument = false; 3057 3058 // TODO: record more information about failed template arguments 3059 Candidate.DeductionFailure.Result = Result; 3060 Candidate.DeductionFailure.TemplateParameter = Info.Param.getOpaqueValue(); 3061 return; 3062 } 3063 3064 // Add the function template specialization produced by template argument 3065 // deduction as a candidate. 3066 assert(Specialization && "Missing function template specialization?"); 3067 AddOverloadCandidate(Specialization, FoundDecl, Args, NumArgs, CandidateSet, 3068 SuppressUserConversions); 3069} 3070 3071/// AddConversionCandidate - Add a C++ conversion function as a 3072/// candidate in the candidate set (C++ [over.match.conv], 3073/// C++ [over.match.copy]). From is the expression we're converting from, 3074/// and ToType is the type that we're eventually trying to convert to 3075/// (which may or may not be the same type as the type that the 3076/// conversion function produces). 3077void 3078Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 3079 DeclAccessPair FoundDecl, 3080 CXXRecordDecl *ActingContext, 3081 Expr *From, QualType ToType, 3082 OverloadCandidateSet& CandidateSet) { 3083 assert(!Conversion->getDescribedFunctionTemplate() && 3084 "Conversion function templates use AddTemplateConversionCandidate"); 3085 QualType ConvType = Conversion->getConversionType().getNonReferenceType(); 3086 if (!CandidateSet.isNewCandidate(Conversion)) 3087 return; 3088 3089 // Overload resolution is always an unevaluated context. 3090 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3091 3092 // Add this candidate 3093 CandidateSet.push_back(OverloadCandidate()); 3094 OverloadCandidate& Candidate = CandidateSet.back(); 3095 Candidate.FoundDecl = FoundDecl; 3096 Candidate.Function = Conversion; 3097 Candidate.IsSurrogate = false; 3098 Candidate.IgnoreObjectArgument = false; 3099 Candidate.FinalConversion.setAsIdentityConversion(); 3100 Candidate.FinalConversion.setFromType(ConvType); 3101 Candidate.FinalConversion.setAllToTypes(ToType); 3102 3103 // Determine the implicit conversion sequence for the implicit 3104 // object parameter. 3105 Candidate.Viable = true; 3106 Candidate.Conversions.resize(1); 3107 Candidate.Conversions[0] 3108 = TryObjectArgumentInitialization(From->getType(), Conversion, 3109 ActingContext); 3110 // Conversion functions to a different type in the base class is visible in 3111 // the derived class. So, a derived to base conversion should not participate 3112 // in overload resolution. 3113 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 3114 Candidate.Conversions[0].Standard.Second = ICK_Identity; 3115 if (Candidate.Conversions[0].isBad()) { 3116 Candidate.Viable = false; 3117 Candidate.FailureKind = ovl_fail_bad_conversion; 3118 return; 3119 } 3120 3121 // We won't go through a user-define type conversion function to convert a 3122 // derived to base as such conversions are given Conversion Rank. They only 3123 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 3124 QualType FromCanon 3125 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 3126 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 3127 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 3128 Candidate.Viable = false; 3129 Candidate.FailureKind = ovl_fail_trivial_conversion; 3130 return; 3131 } 3132 3133 // To determine what the conversion from the result of calling the 3134 // conversion function to the type we're eventually trying to 3135 // convert to (ToType), we need to synthesize a call to the 3136 // conversion function and attempt copy initialization from it. This 3137 // makes sure that we get the right semantics with respect to 3138 // lvalues/rvalues and the type. Fortunately, we can allocate this 3139 // call on the stack and we don't need its arguments to be 3140 // well-formed. 3141 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 3142 From->getLocStart()); 3143 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 3144 CastExpr::CK_FunctionToPointerDecay, 3145 &ConversionRef, false); 3146 3147 // Note that it is safe to allocate CallExpr on the stack here because 3148 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 3149 // allocator). 3150 CallExpr Call(Context, &ConversionFn, 0, 0, 3151 Conversion->getConversionType().getNonReferenceType(), 3152 From->getLocStart()); 3153 ImplicitConversionSequence ICS = 3154 TryCopyInitialization(*this, &Call, ToType, 3155 /*SuppressUserConversions=*/true, 3156 /*InOverloadResolution=*/false); 3157 3158 switch (ICS.getKind()) { 3159 case ImplicitConversionSequence::StandardConversion: 3160 Candidate.FinalConversion = ICS.Standard; 3161 3162 // C++ [over.ics.user]p3: 3163 // If the user-defined conversion is specified by a specialization of a 3164 // conversion function template, the second standard conversion sequence 3165 // shall have exact match rank. 3166 if (Conversion->getPrimaryTemplate() && 3167 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { 3168 Candidate.Viable = false; 3169 Candidate.FailureKind = ovl_fail_final_conversion_not_exact; 3170 } 3171 3172 break; 3173 3174 case ImplicitConversionSequence::BadConversion: 3175 Candidate.Viable = false; 3176 Candidate.FailureKind = ovl_fail_bad_final_conversion; 3177 break; 3178 3179 default: 3180 assert(false && 3181 "Can only end up with a standard conversion sequence or failure"); 3182 } 3183} 3184 3185/// \brief Adds a conversion function template specialization 3186/// candidate to the overload set, using template argument deduction 3187/// to deduce the template arguments of the conversion function 3188/// template from the type that we are converting to (C++ 3189/// [temp.deduct.conv]). 3190void 3191Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 3192 DeclAccessPair FoundDecl, 3193 CXXRecordDecl *ActingDC, 3194 Expr *From, QualType ToType, 3195 OverloadCandidateSet &CandidateSet) { 3196 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 3197 "Only conversion function templates permitted here"); 3198 3199 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3200 return; 3201 3202 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3203 CXXConversionDecl *Specialization = 0; 3204 if (TemplateDeductionResult Result 3205 = DeduceTemplateArguments(FunctionTemplate, ToType, 3206 Specialization, Info)) { 3207 // FIXME: Record what happened with template argument deduction, so 3208 // that we can give the user a beautiful diagnostic. 3209 (void)Result; 3210 return; 3211 } 3212 3213 // Add the conversion function template specialization produced by 3214 // template argument deduction as a candidate. 3215 assert(Specialization && "Missing function template specialization?"); 3216 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, 3217 CandidateSet); 3218} 3219 3220/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 3221/// converts the given @c Object to a function pointer via the 3222/// conversion function @c Conversion, and then attempts to call it 3223/// with the given arguments (C++ [over.call.object]p2-4). Proto is 3224/// the type of function that we'll eventually be calling. 3225void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 3226 DeclAccessPair FoundDecl, 3227 CXXRecordDecl *ActingContext, 3228 const FunctionProtoType *Proto, 3229 QualType ObjectType, 3230 Expr **Args, unsigned NumArgs, 3231 OverloadCandidateSet& CandidateSet) { 3232 if (!CandidateSet.isNewCandidate(Conversion)) 3233 return; 3234 3235 // Overload resolution is always an unevaluated context. 3236 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3237 3238 CandidateSet.push_back(OverloadCandidate()); 3239 OverloadCandidate& Candidate = CandidateSet.back(); 3240 Candidate.FoundDecl = FoundDecl; 3241 Candidate.Function = 0; 3242 Candidate.Surrogate = Conversion; 3243 Candidate.Viable = true; 3244 Candidate.IsSurrogate = true; 3245 Candidate.IgnoreObjectArgument = false; 3246 Candidate.Conversions.resize(NumArgs + 1); 3247 3248 // Determine the implicit conversion sequence for the implicit 3249 // object parameter. 3250 ImplicitConversionSequence ObjectInit 3251 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 3252 if (ObjectInit.isBad()) { 3253 Candidate.Viable = false; 3254 Candidate.FailureKind = ovl_fail_bad_conversion; 3255 Candidate.Conversions[0] = ObjectInit; 3256 return; 3257 } 3258 3259 // The first conversion is actually a user-defined conversion whose 3260 // first conversion is ObjectInit's standard conversion (which is 3261 // effectively a reference binding). Record it as such. 3262 Candidate.Conversions[0].setUserDefined(); 3263 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 3264 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 3265 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 3266 Candidate.Conversions[0].UserDefined.After 3267 = Candidate.Conversions[0].UserDefined.Before; 3268 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 3269 3270 // Find the 3271 unsigned NumArgsInProto = Proto->getNumArgs(); 3272 3273 // (C++ 13.3.2p2): A candidate function having fewer than m 3274 // parameters is viable only if it has an ellipsis in its parameter 3275 // list (8.3.5). 3276 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3277 Candidate.Viable = false; 3278 Candidate.FailureKind = ovl_fail_too_many_arguments; 3279 return; 3280 } 3281 3282 // Function types don't have any default arguments, so just check if 3283 // we have enough arguments. 3284 if (NumArgs < NumArgsInProto) { 3285 // Not enough arguments. 3286 Candidate.Viable = false; 3287 Candidate.FailureKind = ovl_fail_too_few_arguments; 3288 return; 3289 } 3290 3291 // Determine the implicit conversion sequences for each of the 3292 // arguments. 3293 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3294 if (ArgIdx < NumArgsInProto) { 3295 // (C++ 13.3.2p3): for F to be a viable function, there shall 3296 // exist for each argument an implicit conversion sequence 3297 // (13.3.3.1) that converts that argument to the corresponding 3298 // parameter of F. 3299 QualType ParamType = Proto->getArgType(ArgIdx); 3300 Candidate.Conversions[ArgIdx + 1] 3301 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3302 /*SuppressUserConversions=*/false, 3303 /*InOverloadResolution=*/false); 3304 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3305 Candidate.Viable = false; 3306 Candidate.FailureKind = ovl_fail_bad_conversion; 3307 break; 3308 } 3309 } else { 3310 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3311 // argument for which there is no corresponding parameter is 3312 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3313 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3314 } 3315 } 3316} 3317 3318// FIXME: This will eventually be removed, once we've migrated all of the 3319// operator overloading logic over to the scheme used by binary operators, which 3320// works for template instantiation. 3321void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 3322 SourceLocation OpLoc, 3323 Expr **Args, unsigned NumArgs, 3324 OverloadCandidateSet& CandidateSet, 3325 SourceRange OpRange) { 3326 UnresolvedSet<16> Fns; 3327 3328 QualType T1 = Args[0]->getType(); 3329 QualType T2; 3330 if (NumArgs > 1) 3331 T2 = Args[1]->getType(); 3332 3333 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3334 if (S) 3335 LookupOverloadedOperatorName(Op, S, T1, T2, Fns); 3336 AddFunctionCandidates(Fns, Args, NumArgs, CandidateSet, false); 3337 AddArgumentDependentLookupCandidates(OpName, false, Args, NumArgs, 0, 3338 CandidateSet); 3339 AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange); 3340 AddBuiltinOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet); 3341} 3342 3343/// \brief Add overload candidates for overloaded operators that are 3344/// member functions. 3345/// 3346/// Add the overloaded operator candidates that are member functions 3347/// for the operator Op that was used in an operator expression such 3348/// as "x Op y". , Args/NumArgs provides the operator arguments, and 3349/// CandidateSet will store the added overload candidates. (C++ 3350/// [over.match.oper]). 3351void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 3352 SourceLocation OpLoc, 3353 Expr **Args, unsigned NumArgs, 3354 OverloadCandidateSet& CandidateSet, 3355 SourceRange OpRange) { 3356 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3357 3358 // C++ [over.match.oper]p3: 3359 // For a unary operator @ with an operand of a type whose 3360 // cv-unqualified version is T1, and for a binary operator @ with 3361 // a left operand of a type whose cv-unqualified version is T1 and 3362 // a right operand of a type whose cv-unqualified version is T2, 3363 // three sets of candidate functions, designated member 3364 // candidates, non-member candidates and built-in candidates, are 3365 // constructed as follows: 3366 QualType T1 = Args[0]->getType(); 3367 QualType T2; 3368 if (NumArgs > 1) 3369 T2 = Args[1]->getType(); 3370 3371 // -- If T1 is a class type, the set of member candidates is the 3372 // result of the qualified lookup of T1::operator@ 3373 // (13.3.1.1.1); otherwise, the set of member candidates is 3374 // empty. 3375 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 3376 // Complete the type if it can be completed. Otherwise, we're done. 3377 if (RequireCompleteType(OpLoc, T1, PDiag())) 3378 return; 3379 3380 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 3381 LookupQualifiedName(Operators, T1Rec->getDecl()); 3382 Operators.suppressDiagnostics(); 3383 3384 for (LookupResult::iterator Oper = Operators.begin(), 3385 OperEnd = Operators.end(); 3386 Oper != OperEnd; 3387 ++Oper) 3388 AddMethodCandidate(Oper.getPair(), Args[0]->getType(), 3389 Args + 1, NumArgs - 1, CandidateSet, 3390 /* SuppressUserConversions = */ false); 3391 } 3392} 3393 3394/// AddBuiltinCandidate - Add a candidate for a built-in 3395/// operator. ResultTy and ParamTys are the result and parameter types 3396/// of the built-in candidate, respectively. Args and NumArgs are the 3397/// arguments being passed to the candidate. IsAssignmentOperator 3398/// should be true when this built-in candidate is an assignment 3399/// operator. NumContextualBoolArguments is the number of arguments 3400/// (at the beginning of the argument list) that will be contextually 3401/// converted to bool. 3402void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3403 Expr **Args, unsigned NumArgs, 3404 OverloadCandidateSet& CandidateSet, 3405 bool IsAssignmentOperator, 3406 unsigned NumContextualBoolArguments) { 3407 // Overload resolution is always an unevaluated context. 3408 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3409 3410 // Add this candidate 3411 CandidateSet.push_back(OverloadCandidate()); 3412 OverloadCandidate& Candidate = CandidateSet.back(); 3413 Candidate.FoundDecl = DeclAccessPair::make(0, AS_none); 3414 Candidate.Function = 0; 3415 Candidate.IsSurrogate = false; 3416 Candidate.IgnoreObjectArgument = false; 3417 Candidate.BuiltinTypes.ResultTy = ResultTy; 3418 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3419 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3420 3421 // Determine the implicit conversion sequences for each of the 3422 // arguments. 3423 Candidate.Viable = true; 3424 Candidate.Conversions.resize(NumArgs); 3425 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3426 // C++ [over.match.oper]p4: 3427 // For the built-in assignment operators, conversions of the 3428 // left operand are restricted as follows: 3429 // -- no temporaries are introduced to hold the left operand, and 3430 // -- no user-defined conversions are applied to the left 3431 // operand to achieve a type match with the left-most 3432 // parameter of a built-in candidate. 3433 // 3434 // We block these conversions by turning off user-defined 3435 // conversions, since that is the only way that initialization of 3436 // a reference to a non-class type can occur from something that 3437 // is not of the same type. 3438 if (ArgIdx < NumContextualBoolArguments) { 3439 assert(ParamTys[ArgIdx] == Context.BoolTy && 3440 "Contextual conversion to bool requires bool type"); 3441 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3442 } else { 3443 Candidate.Conversions[ArgIdx] 3444 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], 3445 ArgIdx == 0 && IsAssignmentOperator, 3446 /*InOverloadResolution=*/false); 3447 } 3448 if (Candidate.Conversions[ArgIdx].isBad()) { 3449 Candidate.Viable = false; 3450 Candidate.FailureKind = ovl_fail_bad_conversion; 3451 break; 3452 } 3453 } 3454} 3455 3456/// BuiltinCandidateTypeSet - A set of types that will be used for the 3457/// candidate operator functions for built-in operators (C++ 3458/// [over.built]). The types are separated into pointer types and 3459/// enumeration types. 3460class BuiltinCandidateTypeSet { 3461 /// TypeSet - A set of types. 3462 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3463 3464 /// PointerTypes - The set of pointer types that will be used in the 3465 /// built-in candidates. 3466 TypeSet PointerTypes; 3467 3468 /// MemberPointerTypes - The set of member pointer types that will be 3469 /// used in the built-in candidates. 3470 TypeSet MemberPointerTypes; 3471 3472 /// EnumerationTypes - The set of enumeration types that will be 3473 /// used in the built-in candidates. 3474 TypeSet EnumerationTypes; 3475 3476 /// Sema - The semantic analysis instance where we are building the 3477 /// candidate type set. 3478 Sema &SemaRef; 3479 3480 /// Context - The AST context in which we will build the type sets. 3481 ASTContext &Context; 3482 3483 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3484 const Qualifiers &VisibleQuals); 3485 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3486 3487public: 3488 /// iterator - Iterates through the types that are part of the set. 3489 typedef TypeSet::iterator iterator; 3490 3491 BuiltinCandidateTypeSet(Sema &SemaRef) 3492 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3493 3494 void AddTypesConvertedFrom(QualType Ty, 3495 SourceLocation Loc, 3496 bool AllowUserConversions, 3497 bool AllowExplicitConversions, 3498 const Qualifiers &VisibleTypeConversionsQuals); 3499 3500 /// pointer_begin - First pointer type found; 3501 iterator pointer_begin() { return PointerTypes.begin(); } 3502 3503 /// pointer_end - Past the last pointer type found; 3504 iterator pointer_end() { return PointerTypes.end(); } 3505 3506 /// member_pointer_begin - First member pointer type found; 3507 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3508 3509 /// member_pointer_end - Past the last member pointer type found; 3510 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3511 3512 /// enumeration_begin - First enumeration type found; 3513 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3514 3515 /// enumeration_end - Past the last enumeration type found; 3516 iterator enumeration_end() { return EnumerationTypes.end(); } 3517}; 3518 3519/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3520/// the set of pointer types along with any more-qualified variants of 3521/// that type. For example, if @p Ty is "int const *", this routine 3522/// will add "int const *", "int const volatile *", "int const 3523/// restrict *", and "int const volatile restrict *" to the set of 3524/// pointer types. Returns true if the add of @p Ty itself succeeded, 3525/// false otherwise. 3526/// 3527/// FIXME: what to do about extended qualifiers? 3528bool 3529BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3530 const Qualifiers &VisibleQuals) { 3531 3532 // Insert this type. 3533 if (!PointerTypes.insert(Ty)) 3534 return false; 3535 3536 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3537 assert(PointerTy && "type was not a pointer type!"); 3538 3539 QualType PointeeTy = PointerTy->getPointeeType(); 3540 // Don't add qualified variants of arrays. For one, they're not allowed 3541 // (the qualifier would sink to the element type), and for another, the 3542 // only overload situation where it matters is subscript or pointer +- int, 3543 // and those shouldn't have qualifier variants anyway. 3544 if (PointeeTy->isArrayType()) 3545 return true; 3546 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3547 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3548 BaseCVR = Array->getElementType().getCVRQualifiers(); 3549 bool hasVolatile = VisibleQuals.hasVolatile(); 3550 bool hasRestrict = VisibleQuals.hasRestrict(); 3551 3552 // Iterate through all strict supersets of BaseCVR. 3553 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3554 if ((CVR | BaseCVR) != CVR) continue; 3555 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3556 // in the types. 3557 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3558 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3559 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3560 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3561 } 3562 3563 return true; 3564} 3565 3566/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3567/// to the set of pointer types along with any more-qualified variants of 3568/// that type. For example, if @p Ty is "int const *", this routine 3569/// will add "int const *", "int const volatile *", "int const 3570/// restrict *", and "int const volatile restrict *" to the set of 3571/// pointer types. Returns true if the add of @p Ty itself succeeded, 3572/// false otherwise. 3573/// 3574/// FIXME: what to do about extended qualifiers? 3575bool 3576BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3577 QualType Ty) { 3578 // Insert this type. 3579 if (!MemberPointerTypes.insert(Ty)) 3580 return false; 3581 3582 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3583 assert(PointerTy && "type was not a member pointer type!"); 3584 3585 QualType PointeeTy = PointerTy->getPointeeType(); 3586 // Don't add qualified variants of arrays. For one, they're not allowed 3587 // (the qualifier would sink to the element type), and for another, the 3588 // only overload situation where it matters is subscript or pointer +- int, 3589 // and those shouldn't have qualifier variants anyway. 3590 if (PointeeTy->isArrayType()) 3591 return true; 3592 const Type *ClassTy = PointerTy->getClass(); 3593 3594 // Iterate through all strict supersets of the pointee type's CVR 3595 // qualifiers. 3596 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3597 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3598 if ((CVR | BaseCVR) != CVR) continue; 3599 3600 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3601 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3602 } 3603 3604 return true; 3605} 3606 3607/// AddTypesConvertedFrom - Add each of the types to which the type @p 3608/// Ty can be implicit converted to the given set of @p Types. We're 3609/// primarily interested in pointer types and enumeration types. We also 3610/// take member pointer types, for the conditional operator. 3611/// AllowUserConversions is true if we should look at the conversion 3612/// functions of a class type, and AllowExplicitConversions if we 3613/// should also include the explicit conversion functions of a class 3614/// type. 3615void 3616BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3617 SourceLocation Loc, 3618 bool AllowUserConversions, 3619 bool AllowExplicitConversions, 3620 const Qualifiers &VisibleQuals) { 3621 // Only deal with canonical types. 3622 Ty = Context.getCanonicalType(Ty); 3623 3624 // Look through reference types; they aren't part of the type of an 3625 // expression for the purposes of conversions. 3626 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3627 Ty = RefTy->getPointeeType(); 3628 3629 // We don't care about qualifiers on the type. 3630 Ty = Ty.getLocalUnqualifiedType(); 3631 3632 // If we're dealing with an array type, decay to the pointer. 3633 if (Ty->isArrayType()) 3634 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3635 3636 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3637 QualType PointeeTy = PointerTy->getPointeeType(); 3638 3639 // Insert our type, and its more-qualified variants, into the set 3640 // of types. 3641 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3642 return; 3643 } else if (Ty->isMemberPointerType()) { 3644 // Member pointers are far easier, since the pointee can't be converted. 3645 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3646 return; 3647 } else if (Ty->isEnumeralType()) { 3648 EnumerationTypes.insert(Ty); 3649 } else if (AllowUserConversions) { 3650 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3651 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3652 // No conversion functions in incomplete types. 3653 return; 3654 } 3655 3656 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3657 const UnresolvedSetImpl *Conversions 3658 = ClassDecl->getVisibleConversionFunctions(); 3659 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3660 E = Conversions->end(); I != E; ++I) { 3661 NamedDecl *D = I.getDecl(); 3662 if (isa<UsingShadowDecl>(D)) 3663 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3664 3665 // Skip conversion function templates; they don't tell us anything 3666 // about which builtin types we can convert to. 3667 if (isa<FunctionTemplateDecl>(D)) 3668 continue; 3669 3670 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 3671 if (AllowExplicitConversions || !Conv->isExplicit()) { 3672 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3673 VisibleQuals); 3674 } 3675 } 3676 } 3677 } 3678} 3679 3680/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3681/// the volatile- and non-volatile-qualified assignment operators for the 3682/// given type to the candidate set. 3683static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3684 QualType T, 3685 Expr **Args, 3686 unsigned NumArgs, 3687 OverloadCandidateSet &CandidateSet) { 3688 QualType ParamTypes[2]; 3689 3690 // T& operator=(T&, T) 3691 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3692 ParamTypes[1] = T; 3693 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3694 /*IsAssignmentOperator=*/true); 3695 3696 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3697 // volatile T& operator=(volatile T&, T) 3698 ParamTypes[0] 3699 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3700 ParamTypes[1] = T; 3701 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3702 /*IsAssignmentOperator=*/true); 3703 } 3704} 3705 3706/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3707/// if any, found in visible type conversion functions found in ArgExpr's type. 3708static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3709 Qualifiers VRQuals; 3710 const RecordType *TyRec; 3711 if (const MemberPointerType *RHSMPType = 3712 ArgExpr->getType()->getAs<MemberPointerType>()) 3713 TyRec = cast<RecordType>(RHSMPType->getClass()); 3714 else 3715 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3716 if (!TyRec) { 3717 // Just to be safe, assume the worst case. 3718 VRQuals.addVolatile(); 3719 VRQuals.addRestrict(); 3720 return VRQuals; 3721 } 3722 3723 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3724 if (!ClassDecl->hasDefinition()) 3725 return VRQuals; 3726 3727 const UnresolvedSetImpl *Conversions = 3728 ClassDecl->getVisibleConversionFunctions(); 3729 3730 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3731 E = Conversions->end(); I != E; ++I) { 3732 NamedDecl *D = I.getDecl(); 3733 if (isa<UsingShadowDecl>(D)) 3734 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3735 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { 3736 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3737 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3738 CanTy = ResTypeRef->getPointeeType(); 3739 // Need to go down the pointer/mempointer chain and add qualifiers 3740 // as see them. 3741 bool done = false; 3742 while (!done) { 3743 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3744 CanTy = ResTypePtr->getPointeeType(); 3745 else if (const MemberPointerType *ResTypeMPtr = 3746 CanTy->getAs<MemberPointerType>()) 3747 CanTy = ResTypeMPtr->getPointeeType(); 3748 else 3749 done = true; 3750 if (CanTy.isVolatileQualified()) 3751 VRQuals.addVolatile(); 3752 if (CanTy.isRestrictQualified()) 3753 VRQuals.addRestrict(); 3754 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3755 return VRQuals; 3756 } 3757 } 3758 } 3759 return VRQuals; 3760} 3761 3762/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3763/// operator overloads to the candidate set (C++ [over.built]), based 3764/// on the operator @p Op and the arguments given. For example, if the 3765/// operator is a binary '+', this routine might add "int 3766/// operator+(int, int)" to cover integer addition. 3767void 3768Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3769 SourceLocation OpLoc, 3770 Expr **Args, unsigned NumArgs, 3771 OverloadCandidateSet& CandidateSet) { 3772 // The set of "promoted arithmetic types", which are the arithmetic 3773 // types are that preserved by promotion (C++ [over.built]p2). Note 3774 // that the first few of these types are the promoted integral 3775 // types; these types need to be first. 3776 // FIXME: What about complex? 3777 const unsigned FirstIntegralType = 0; 3778 const unsigned LastIntegralType = 13; 3779 const unsigned FirstPromotedIntegralType = 7, 3780 LastPromotedIntegralType = 13; 3781 const unsigned FirstPromotedArithmeticType = 7, 3782 LastPromotedArithmeticType = 16; 3783 const unsigned NumArithmeticTypes = 16; 3784 QualType ArithmeticTypes[NumArithmeticTypes] = { 3785 Context.BoolTy, Context.CharTy, Context.WCharTy, 3786// FIXME: Context.Char16Ty, Context.Char32Ty, 3787 Context.SignedCharTy, Context.ShortTy, 3788 Context.UnsignedCharTy, Context.UnsignedShortTy, 3789 Context.IntTy, Context.LongTy, Context.LongLongTy, 3790 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 3791 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 3792 }; 3793 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 3794 "Invalid first promoted integral type"); 3795 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 3796 == Context.UnsignedLongLongTy && 3797 "Invalid last promoted integral type"); 3798 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 3799 "Invalid first promoted arithmetic type"); 3800 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 3801 == Context.LongDoubleTy && 3802 "Invalid last promoted arithmetic type"); 3803 3804 // Find all of the types that the arguments can convert to, but only 3805 // if the operator we're looking at has built-in operator candidates 3806 // that make use of these types. 3807 Qualifiers VisibleTypeConversionsQuals; 3808 VisibleTypeConversionsQuals.addConst(); 3809 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3810 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 3811 3812 BuiltinCandidateTypeSet CandidateTypes(*this); 3813 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 3814 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 3815 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 3816 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 3817 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 3818 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 3819 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3820 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 3821 OpLoc, 3822 true, 3823 (Op == OO_Exclaim || 3824 Op == OO_AmpAmp || 3825 Op == OO_PipePipe), 3826 VisibleTypeConversionsQuals); 3827 } 3828 3829 bool isComparison = false; 3830 switch (Op) { 3831 case OO_None: 3832 case NUM_OVERLOADED_OPERATORS: 3833 assert(false && "Expected an overloaded operator"); 3834 break; 3835 3836 case OO_Star: // '*' is either unary or binary 3837 if (NumArgs == 1) 3838 goto UnaryStar; 3839 else 3840 goto BinaryStar; 3841 break; 3842 3843 case OO_Plus: // '+' is either unary or binary 3844 if (NumArgs == 1) 3845 goto UnaryPlus; 3846 else 3847 goto BinaryPlus; 3848 break; 3849 3850 case OO_Minus: // '-' is either unary or binary 3851 if (NumArgs == 1) 3852 goto UnaryMinus; 3853 else 3854 goto BinaryMinus; 3855 break; 3856 3857 case OO_Amp: // '&' is either unary or binary 3858 if (NumArgs == 1) 3859 goto UnaryAmp; 3860 else 3861 goto BinaryAmp; 3862 3863 case OO_PlusPlus: 3864 case OO_MinusMinus: 3865 // C++ [over.built]p3: 3866 // 3867 // For every pair (T, VQ), where T is an arithmetic type, and VQ 3868 // is either volatile or empty, there exist candidate operator 3869 // functions of the form 3870 // 3871 // VQ T& operator++(VQ T&); 3872 // T operator++(VQ T&, int); 3873 // 3874 // C++ [over.built]p4: 3875 // 3876 // For every pair (T, VQ), where T is an arithmetic type other 3877 // than bool, and VQ is either volatile or empty, there exist 3878 // candidate operator functions of the form 3879 // 3880 // VQ T& operator--(VQ T&); 3881 // T operator--(VQ T&, int); 3882 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 3883 Arith < NumArithmeticTypes; ++Arith) { 3884 QualType ArithTy = ArithmeticTypes[Arith]; 3885 QualType ParamTypes[2] 3886 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 3887 3888 // Non-volatile version. 3889 if (NumArgs == 1) 3890 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3891 else 3892 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3893 // heuristic to reduce number of builtin candidates in the set. 3894 // Add volatile version only if there are conversions to a volatile type. 3895 if (VisibleTypeConversionsQuals.hasVolatile()) { 3896 // Volatile version 3897 ParamTypes[0] 3898 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 3899 if (NumArgs == 1) 3900 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3901 else 3902 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3903 } 3904 } 3905 3906 // C++ [over.built]p5: 3907 // 3908 // For every pair (T, VQ), where T is a cv-qualified or 3909 // cv-unqualified object type, and VQ is either volatile or 3910 // empty, there exist candidate operator functions of the form 3911 // 3912 // T*VQ& operator++(T*VQ&); 3913 // T*VQ& operator--(T*VQ&); 3914 // T* operator++(T*VQ&, int); 3915 // T* operator--(T*VQ&, int); 3916 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3917 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3918 // Skip pointer types that aren't pointers to object types. 3919 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 3920 continue; 3921 3922 QualType ParamTypes[2] = { 3923 Context.getLValueReferenceType(*Ptr), Context.IntTy 3924 }; 3925 3926 // Without volatile 3927 if (NumArgs == 1) 3928 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3929 else 3930 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3931 3932 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 3933 VisibleTypeConversionsQuals.hasVolatile()) { 3934 // With volatile 3935 ParamTypes[0] 3936 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 3937 if (NumArgs == 1) 3938 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3939 else 3940 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3941 } 3942 } 3943 break; 3944 3945 UnaryStar: 3946 // C++ [over.built]p6: 3947 // For every cv-qualified or cv-unqualified object type T, there 3948 // exist candidate operator functions of the form 3949 // 3950 // T& operator*(T*); 3951 // 3952 // C++ [over.built]p7: 3953 // For every function type T, there exist candidate operator 3954 // functions of the form 3955 // T& operator*(T*); 3956 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3957 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3958 QualType ParamTy = *Ptr; 3959 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 3960 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 3961 &ParamTy, Args, 1, CandidateSet); 3962 } 3963 break; 3964 3965 UnaryPlus: 3966 // C++ [over.built]p8: 3967 // For every type T, there exist candidate operator functions of 3968 // the form 3969 // 3970 // T* operator+(T*); 3971 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3972 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3973 QualType ParamTy = *Ptr; 3974 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 3975 } 3976 3977 // Fall through 3978 3979 UnaryMinus: 3980 // C++ [over.built]p9: 3981 // For every promoted arithmetic type T, there exist candidate 3982 // operator functions of the form 3983 // 3984 // T operator+(T); 3985 // T operator-(T); 3986 for (unsigned Arith = FirstPromotedArithmeticType; 3987 Arith < LastPromotedArithmeticType; ++Arith) { 3988 QualType ArithTy = ArithmeticTypes[Arith]; 3989 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 3990 } 3991 break; 3992 3993 case OO_Tilde: 3994 // C++ [over.built]p10: 3995 // For every promoted integral type T, there exist candidate 3996 // operator functions of the form 3997 // 3998 // T operator~(T); 3999 for (unsigned Int = FirstPromotedIntegralType; 4000 Int < LastPromotedIntegralType; ++Int) { 4001 QualType IntTy = ArithmeticTypes[Int]; 4002 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 4003 } 4004 break; 4005 4006 case OO_New: 4007 case OO_Delete: 4008 case OO_Array_New: 4009 case OO_Array_Delete: 4010 case OO_Call: 4011 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 4012 break; 4013 4014 case OO_Comma: 4015 UnaryAmp: 4016 case OO_Arrow: 4017 // C++ [over.match.oper]p3: 4018 // -- For the operator ',', the unary operator '&', or the 4019 // operator '->', the built-in candidates set is empty. 4020 break; 4021 4022 case OO_EqualEqual: 4023 case OO_ExclaimEqual: 4024 // C++ [over.match.oper]p16: 4025 // For every pointer to member type T, there exist candidate operator 4026 // functions of the form 4027 // 4028 // bool operator==(T,T); 4029 // bool operator!=(T,T); 4030 for (BuiltinCandidateTypeSet::iterator 4031 MemPtr = CandidateTypes.member_pointer_begin(), 4032 MemPtrEnd = CandidateTypes.member_pointer_end(); 4033 MemPtr != MemPtrEnd; 4034 ++MemPtr) { 4035 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 4036 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4037 } 4038 4039 // Fall through 4040 4041 case OO_Less: 4042 case OO_Greater: 4043 case OO_LessEqual: 4044 case OO_GreaterEqual: 4045 // C++ [over.built]p15: 4046 // 4047 // For every pointer or enumeration type T, there exist 4048 // candidate operator functions of the form 4049 // 4050 // bool operator<(T, T); 4051 // bool operator>(T, T); 4052 // bool operator<=(T, T); 4053 // bool operator>=(T, T); 4054 // bool operator==(T, T); 4055 // bool operator!=(T, T); 4056 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4057 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4058 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4059 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4060 } 4061 for (BuiltinCandidateTypeSet::iterator Enum 4062 = CandidateTypes.enumeration_begin(); 4063 Enum != CandidateTypes.enumeration_end(); ++Enum) { 4064 QualType ParamTypes[2] = { *Enum, *Enum }; 4065 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4066 } 4067 4068 // Fall through. 4069 isComparison = true; 4070 4071 BinaryPlus: 4072 BinaryMinus: 4073 if (!isComparison) { 4074 // We didn't fall through, so we must have OO_Plus or OO_Minus. 4075 4076 // C++ [over.built]p13: 4077 // 4078 // For every cv-qualified or cv-unqualified object type T 4079 // there exist candidate operator functions of the form 4080 // 4081 // T* operator+(T*, ptrdiff_t); 4082 // T& operator[](T*, ptrdiff_t); [BELOW] 4083 // T* operator-(T*, ptrdiff_t); 4084 // T* operator+(ptrdiff_t, T*); 4085 // T& operator[](ptrdiff_t, T*); [BELOW] 4086 // 4087 // C++ [over.built]p14: 4088 // 4089 // For every T, where T is a pointer to object type, there 4090 // exist candidate operator functions of the form 4091 // 4092 // ptrdiff_t operator-(T, T); 4093 for (BuiltinCandidateTypeSet::iterator Ptr 4094 = CandidateTypes.pointer_begin(); 4095 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4096 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4097 4098 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 4099 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4100 4101 if (Op == OO_Plus) { 4102 // T* operator+(ptrdiff_t, T*); 4103 ParamTypes[0] = ParamTypes[1]; 4104 ParamTypes[1] = *Ptr; 4105 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4106 } else { 4107 // ptrdiff_t operator-(T, T); 4108 ParamTypes[1] = *Ptr; 4109 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 4110 Args, 2, CandidateSet); 4111 } 4112 } 4113 } 4114 // Fall through 4115 4116 case OO_Slash: 4117 BinaryStar: 4118 Conditional: 4119 // C++ [over.built]p12: 4120 // 4121 // For every pair of promoted arithmetic types L and R, there 4122 // exist candidate operator functions of the form 4123 // 4124 // LR operator*(L, R); 4125 // LR operator/(L, R); 4126 // LR operator+(L, R); 4127 // LR operator-(L, R); 4128 // bool operator<(L, R); 4129 // bool operator>(L, R); 4130 // bool operator<=(L, R); 4131 // bool operator>=(L, R); 4132 // bool operator==(L, R); 4133 // bool operator!=(L, R); 4134 // 4135 // where LR is the result of the usual arithmetic conversions 4136 // between types L and R. 4137 // 4138 // C++ [over.built]p24: 4139 // 4140 // For every pair of promoted arithmetic types L and R, there exist 4141 // candidate operator functions of the form 4142 // 4143 // LR operator?(bool, L, R); 4144 // 4145 // where LR is the result of the usual arithmetic conversions 4146 // between types L and R. 4147 // Our candidates ignore the first parameter. 4148 for (unsigned Left = FirstPromotedArithmeticType; 4149 Left < LastPromotedArithmeticType; ++Left) { 4150 for (unsigned Right = FirstPromotedArithmeticType; 4151 Right < LastPromotedArithmeticType; ++Right) { 4152 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4153 QualType Result 4154 = isComparison 4155 ? Context.BoolTy 4156 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4157 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4158 } 4159 } 4160 break; 4161 4162 case OO_Percent: 4163 BinaryAmp: 4164 case OO_Caret: 4165 case OO_Pipe: 4166 case OO_LessLess: 4167 case OO_GreaterGreater: 4168 // C++ [over.built]p17: 4169 // 4170 // For every pair of promoted integral types L and R, there 4171 // exist candidate operator functions of the form 4172 // 4173 // LR operator%(L, R); 4174 // LR operator&(L, R); 4175 // LR operator^(L, R); 4176 // LR operator|(L, R); 4177 // L operator<<(L, R); 4178 // L operator>>(L, R); 4179 // 4180 // where LR is the result of the usual arithmetic conversions 4181 // between types L and R. 4182 for (unsigned Left = FirstPromotedIntegralType; 4183 Left < LastPromotedIntegralType; ++Left) { 4184 for (unsigned Right = FirstPromotedIntegralType; 4185 Right < LastPromotedIntegralType; ++Right) { 4186 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4187 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 4188 ? LandR[0] 4189 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4190 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4191 } 4192 } 4193 break; 4194 4195 case OO_Equal: 4196 // C++ [over.built]p20: 4197 // 4198 // For every pair (T, VQ), where T is an enumeration or 4199 // pointer to member type and VQ is either volatile or 4200 // empty, there exist candidate operator functions of the form 4201 // 4202 // VQ T& operator=(VQ T&, T); 4203 for (BuiltinCandidateTypeSet::iterator 4204 Enum = CandidateTypes.enumeration_begin(), 4205 EnumEnd = CandidateTypes.enumeration_end(); 4206 Enum != EnumEnd; ++Enum) 4207 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 4208 CandidateSet); 4209 for (BuiltinCandidateTypeSet::iterator 4210 MemPtr = CandidateTypes.member_pointer_begin(), 4211 MemPtrEnd = CandidateTypes.member_pointer_end(); 4212 MemPtr != MemPtrEnd; ++MemPtr) 4213 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 4214 CandidateSet); 4215 // Fall through. 4216 4217 case OO_PlusEqual: 4218 case OO_MinusEqual: 4219 // C++ [over.built]p19: 4220 // 4221 // For every pair (T, VQ), where T is any type and VQ is either 4222 // volatile or empty, there exist candidate operator functions 4223 // of the form 4224 // 4225 // T*VQ& operator=(T*VQ&, T*); 4226 // 4227 // C++ [over.built]p21: 4228 // 4229 // For every pair (T, VQ), where T is a cv-qualified or 4230 // cv-unqualified object type and VQ is either volatile or 4231 // empty, there exist candidate operator functions of the form 4232 // 4233 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 4234 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 4235 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4236 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4237 QualType ParamTypes[2]; 4238 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 4239 4240 // non-volatile version 4241 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 4242 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4243 /*IsAssigmentOperator=*/Op == OO_Equal); 4244 4245 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4246 VisibleTypeConversionsQuals.hasVolatile()) { 4247 // volatile version 4248 ParamTypes[0] 4249 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4250 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4251 /*IsAssigmentOperator=*/Op == OO_Equal); 4252 } 4253 } 4254 // Fall through. 4255 4256 case OO_StarEqual: 4257 case OO_SlashEqual: 4258 // C++ [over.built]p18: 4259 // 4260 // For every triple (L, VQ, R), where L is an arithmetic type, 4261 // VQ is either volatile or empty, and R is a promoted 4262 // arithmetic type, there exist candidate operator functions of 4263 // the form 4264 // 4265 // VQ L& operator=(VQ L&, R); 4266 // VQ L& operator*=(VQ L&, R); 4267 // VQ L& operator/=(VQ L&, R); 4268 // VQ L& operator+=(VQ L&, R); 4269 // VQ L& operator-=(VQ L&, R); 4270 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 4271 for (unsigned Right = FirstPromotedArithmeticType; 4272 Right < LastPromotedArithmeticType; ++Right) { 4273 QualType ParamTypes[2]; 4274 ParamTypes[1] = ArithmeticTypes[Right]; 4275 4276 // Add this built-in operator as a candidate (VQ is empty). 4277 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4278 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4279 /*IsAssigmentOperator=*/Op == OO_Equal); 4280 4281 // Add this built-in operator as a candidate (VQ is 'volatile'). 4282 if (VisibleTypeConversionsQuals.hasVolatile()) { 4283 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 4284 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4285 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4286 /*IsAssigmentOperator=*/Op == OO_Equal); 4287 } 4288 } 4289 } 4290 break; 4291 4292 case OO_PercentEqual: 4293 case OO_LessLessEqual: 4294 case OO_GreaterGreaterEqual: 4295 case OO_AmpEqual: 4296 case OO_CaretEqual: 4297 case OO_PipeEqual: 4298 // C++ [over.built]p22: 4299 // 4300 // For every triple (L, VQ, R), where L is an integral type, VQ 4301 // is either volatile or empty, and R is a promoted integral 4302 // type, there exist candidate operator functions of the form 4303 // 4304 // VQ L& operator%=(VQ L&, R); 4305 // VQ L& operator<<=(VQ L&, R); 4306 // VQ L& operator>>=(VQ L&, R); 4307 // VQ L& operator&=(VQ L&, R); 4308 // VQ L& operator^=(VQ L&, R); 4309 // VQ L& operator|=(VQ L&, R); 4310 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 4311 for (unsigned Right = FirstPromotedIntegralType; 4312 Right < LastPromotedIntegralType; ++Right) { 4313 QualType ParamTypes[2]; 4314 ParamTypes[1] = ArithmeticTypes[Right]; 4315 4316 // Add this built-in operator as a candidate (VQ is empty). 4317 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4318 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4319 if (VisibleTypeConversionsQuals.hasVolatile()) { 4320 // Add this built-in operator as a candidate (VQ is 'volatile'). 4321 ParamTypes[0] = ArithmeticTypes[Left]; 4322 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 4323 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4324 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4325 } 4326 } 4327 } 4328 break; 4329 4330 case OO_Exclaim: { 4331 // C++ [over.operator]p23: 4332 // 4333 // There also exist candidate operator functions of the form 4334 // 4335 // bool operator!(bool); 4336 // bool operator&&(bool, bool); [BELOW] 4337 // bool operator||(bool, bool); [BELOW] 4338 QualType ParamTy = Context.BoolTy; 4339 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 4340 /*IsAssignmentOperator=*/false, 4341 /*NumContextualBoolArguments=*/1); 4342 break; 4343 } 4344 4345 case OO_AmpAmp: 4346 case OO_PipePipe: { 4347 // C++ [over.operator]p23: 4348 // 4349 // There also exist candidate operator functions of the form 4350 // 4351 // bool operator!(bool); [ABOVE] 4352 // bool operator&&(bool, bool); 4353 // bool operator||(bool, bool); 4354 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 4355 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 4356 /*IsAssignmentOperator=*/false, 4357 /*NumContextualBoolArguments=*/2); 4358 break; 4359 } 4360 4361 case OO_Subscript: 4362 // C++ [over.built]p13: 4363 // 4364 // For every cv-qualified or cv-unqualified object type T there 4365 // exist candidate operator functions of the form 4366 // 4367 // T* operator+(T*, ptrdiff_t); [ABOVE] 4368 // T& operator[](T*, ptrdiff_t); 4369 // T* operator-(T*, ptrdiff_t); [ABOVE] 4370 // T* operator+(ptrdiff_t, T*); [ABOVE] 4371 // T& operator[](ptrdiff_t, T*); 4372 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4373 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4374 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4375 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 4376 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 4377 4378 // T& operator[](T*, ptrdiff_t) 4379 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4380 4381 // T& operator[](ptrdiff_t, T*); 4382 ParamTypes[0] = ParamTypes[1]; 4383 ParamTypes[1] = *Ptr; 4384 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4385 } 4386 break; 4387 4388 case OO_ArrowStar: 4389 // C++ [over.built]p11: 4390 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 4391 // C1 is the same type as C2 or is a derived class of C2, T is an object 4392 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 4393 // there exist candidate operator functions of the form 4394 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 4395 // where CV12 is the union of CV1 and CV2. 4396 { 4397 for (BuiltinCandidateTypeSet::iterator Ptr = 4398 CandidateTypes.pointer_begin(); 4399 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4400 QualType C1Ty = (*Ptr); 4401 QualType C1; 4402 QualifierCollector Q1; 4403 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 4404 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 4405 if (!isa<RecordType>(C1)) 4406 continue; 4407 // heuristic to reduce number of builtin candidates in the set. 4408 // Add volatile/restrict version only if there are conversions to a 4409 // volatile/restrict type. 4410 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 4411 continue; 4412 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4413 continue; 4414 } 4415 for (BuiltinCandidateTypeSet::iterator 4416 MemPtr = CandidateTypes.member_pointer_begin(), 4417 MemPtrEnd = CandidateTypes.member_pointer_end(); 4418 MemPtr != MemPtrEnd; ++MemPtr) { 4419 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4420 QualType C2 = QualType(mptr->getClass(), 0); 4421 C2 = C2.getUnqualifiedType(); 4422 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4423 break; 4424 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4425 // build CV12 T& 4426 QualType T = mptr->getPointeeType(); 4427 if (!VisibleTypeConversionsQuals.hasVolatile() && 4428 T.isVolatileQualified()) 4429 continue; 4430 if (!VisibleTypeConversionsQuals.hasRestrict() && 4431 T.isRestrictQualified()) 4432 continue; 4433 T = Q1.apply(T); 4434 QualType ResultTy = Context.getLValueReferenceType(T); 4435 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4436 } 4437 } 4438 } 4439 break; 4440 4441 case OO_Conditional: 4442 // Note that we don't consider the first argument, since it has been 4443 // contextually converted to bool long ago. The candidates below are 4444 // therefore added as binary. 4445 // 4446 // C++ [over.built]p24: 4447 // For every type T, where T is a pointer or pointer-to-member type, 4448 // there exist candidate operator functions of the form 4449 // 4450 // T operator?(bool, T, T); 4451 // 4452 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4453 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4454 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4455 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4456 } 4457 for (BuiltinCandidateTypeSet::iterator Ptr = 4458 CandidateTypes.member_pointer_begin(), 4459 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4460 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4461 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4462 } 4463 goto Conditional; 4464 } 4465} 4466 4467/// \brief Add function candidates found via argument-dependent lookup 4468/// to the set of overloading candidates. 4469/// 4470/// This routine performs argument-dependent name lookup based on the 4471/// given function name (which may also be an operator name) and adds 4472/// all of the overload candidates found by ADL to the overload 4473/// candidate set (C++ [basic.lookup.argdep]). 4474void 4475Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4476 bool Operator, 4477 Expr **Args, unsigned NumArgs, 4478 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4479 OverloadCandidateSet& CandidateSet, 4480 bool PartialOverloading) { 4481 ADLResult Fns; 4482 4483 // FIXME: This approach for uniquing ADL results (and removing 4484 // redundant candidates from the set) relies on pointer-equality, 4485 // which means we need to key off the canonical decl. However, 4486 // always going back to the canonical decl might not get us the 4487 // right set of default arguments. What default arguments are 4488 // we supposed to consider on ADL candidates, anyway? 4489 4490 // FIXME: Pass in the explicit template arguments? 4491 ArgumentDependentLookup(Name, Operator, Args, NumArgs, Fns); 4492 4493 // Erase all of the candidates we already knew about. 4494 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4495 CandEnd = CandidateSet.end(); 4496 Cand != CandEnd; ++Cand) 4497 if (Cand->Function) { 4498 Fns.erase(Cand->Function); 4499 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4500 Fns.erase(FunTmpl); 4501 } 4502 4503 // For each of the ADL candidates we found, add it to the overload 4504 // set. 4505 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 4506 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); 4507 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 4508 if (ExplicitTemplateArgs) 4509 continue; 4510 4511 AddOverloadCandidate(FD, FoundDecl, Args, NumArgs, CandidateSet, 4512 false, PartialOverloading); 4513 } else 4514 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), 4515 FoundDecl, ExplicitTemplateArgs, 4516 Args, NumArgs, CandidateSet); 4517 } 4518} 4519 4520/// isBetterOverloadCandidate - Determines whether the first overload 4521/// candidate is a better candidate than the second (C++ 13.3.3p1). 4522bool 4523Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4524 const OverloadCandidate& Cand2, 4525 SourceLocation Loc) { 4526 // Define viable functions to be better candidates than non-viable 4527 // functions. 4528 if (!Cand2.Viable) 4529 return Cand1.Viable; 4530 else if (!Cand1.Viable) 4531 return false; 4532 4533 // C++ [over.match.best]p1: 4534 // 4535 // -- if F is a static member function, ICS1(F) is defined such 4536 // that ICS1(F) is neither better nor worse than ICS1(G) for 4537 // any function G, and, symmetrically, ICS1(G) is neither 4538 // better nor worse than ICS1(F). 4539 unsigned StartArg = 0; 4540 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4541 StartArg = 1; 4542 4543 // C++ [over.match.best]p1: 4544 // A viable function F1 is defined to be a better function than another 4545 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4546 // conversion sequence than ICSi(F2), and then... 4547 unsigned NumArgs = Cand1.Conversions.size(); 4548 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4549 bool HasBetterConversion = false; 4550 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4551 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4552 Cand2.Conversions[ArgIdx])) { 4553 case ImplicitConversionSequence::Better: 4554 // Cand1 has a better conversion sequence. 4555 HasBetterConversion = true; 4556 break; 4557 4558 case ImplicitConversionSequence::Worse: 4559 // Cand1 can't be better than Cand2. 4560 return false; 4561 4562 case ImplicitConversionSequence::Indistinguishable: 4563 // Do nothing. 4564 break; 4565 } 4566 } 4567 4568 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4569 // ICSj(F2), or, if not that, 4570 if (HasBetterConversion) 4571 return true; 4572 4573 // - F1 is a non-template function and F2 is a function template 4574 // specialization, or, if not that, 4575 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4576 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4577 return true; 4578 4579 // -- F1 and F2 are function template specializations, and the function 4580 // template for F1 is more specialized than the template for F2 4581 // according to the partial ordering rules described in 14.5.5.2, or, 4582 // if not that, 4583 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4584 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4585 if (FunctionTemplateDecl *BetterTemplate 4586 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4587 Cand2.Function->getPrimaryTemplate(), 4588 Loc, 4589 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4590 : TPOC_Call)) 4591 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4592 4593 // -- the context is an initialization by user-defined conversion 4594 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4595 // from the return type of F1 to the destination type (i.e., 4596 // the type of the entity being initialized) is a better 4597 // conversion sequence than the standard conversion sequence 4598 // from the return type of F2 to the destination type. 4599 if (Cand1.Function && Cand2.Function && 4600 isa<CXXConversionDecl>(Cand1.Function) && 4601 isa<CXXConversionDecl>(Cand2.Function)) { 4602 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4603 Cand2.FinalConversion)) { 4604 case ImplicitConversionSequence::Better: 4605 // Cand1 has a better conversion sequence. 4606 return true; 4607 4608 case ImplicitConversionSequence::Worse: 4609 // Cand1 can't be better than Cand2. 4610 return false; 4611 4612 case ImplicitConversionSequence::Indistinguishable: 4613 // Do nothing 4614 break; 4615 } 4616 } 4617 4618 return false; 4619} 4620 4621/// \brief Computes the best viable function (C++ 13.3.3) 4622/// within an overload candidate set. 4623/// 4624/// \param CandidateSet the set of candidate functions. 4625/// 4626/// \param Loc the location of the function name (or operator symbol) for 4627/// which overload resolution occurs. 4628/// 4629/// \param Best f overload resolution was successful or found a deleted 4630/// function, Best points to the candidate function found. 4631/// 4632/// \returns The result of overload resolution. 4633OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4634 SourceLocation Loc, 4635 OverloadCandidateSet::iterator& Best) { 4636 // Find the best viable function. 4637 Best = CandidateSet.end(); 4638 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4639 Cand != CandidateSet.end(); ++Cand) { 4640 if (Cand->Viable) { 4641 if (Best == CandidateSet.end() || 4642 isBetterOverloadCandidate(*Cand, *Best, Loc)) 4643 Best = Cand; 4644 } 4645 } 4646 4647 // If we didn't find any viable functions, abort. 4648 if (Best == CandidateSet.end()) 4649 return OR_No_Viable_Function; 4650 4651 // Make sure that this function is better than every other viable 4652 // function. If not, we have an ambiguity. 4653 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4654 Cand != CandidateSet.end(); ++Cand) { 4655 if (Cand->Viable && 4656 Cand != Best && 4657 !isBetterOverloadCandidate(*Best, *Cand, Loc)) { 4658 Best = CandidateSet.end(); 4659 return OR_Ambiguous; 4660 } 4661 } 4662 4663 // Best is the best viable function. 4664 if (Best->Function && 4665 (Best->Function->isDeleted() || 4666 Best->Function->getAttr<UnavailableAttr>())) 4667 return OR_Deleted; 4668 4669 // C++ [basic.def.odr]p2: 4670 // An overloaded function is used if it is selected by overload resolution 4671 // when referred to from a potentially-evaluated expression. [Note: this 4672 // covers calls to named functions (5.2.2), operator overloading 4673 // (clause 13), user-defined conversions (12.3.2), allocation function for 4674 // placement new (5.3.4), as well as non-default initialization (8.5). 4675 if (Best->Function) 4676 MarkDeclarationReferenced(Loc, Best->Function); 4677 return OR_Success; 4678} 4679 4680namespace { 4681 4682enum OverloadCandidateKind { 4683 oc_function, 4684 oc_method, 4685 oc_constructor, 4686 oc_function_template, 4687 oc_method_template, 4688 oc_constructor_template, 4689 oc_implicit_default_constructor, 4690 oc_implicit_copy_constructor, 4691 oc_implicit_copy_assignment 4692}; 4693 4694OverloadCandidateKind ClassifyOverloadCandidate(Sema &S, 4695 FunctionDecl *Fn, 4696 std::string &Description) { 4697 bool isTemplate = false; 4698 4699 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { 4700 isTemplate = true; 4701 Description = S.getTemplateArgumentBindingsText( 4702 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); 4703 } 4704 4705 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4706 if (!Ctor->isImplicit()) 4707 return isTemplate ? oc_constructor_template : oc_constructor; 4708 4709 return Ctor->isCopyConstructor() ? oc_implicit_copy_constructor 4710 : oc_implicit_default_constructor; 4711 } 4712 4713 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4714 // This actually gets spelled 'candidate function' for now, but 4715 // it doesn't hurt to split it out. 4716 if (!Meth->isImplicit()) 4717 return isTemplate ? oc_method_template : oc_method; 4718 4719 assert(Meth->isCopyAssignment() 4720 && "implicit method is not copy assignment operator?"); 4721 return oc_implicit_copy_assignment; 4722 } 4723 4724 return isTemplate ? oc_function_template : oc_function; 4725} 4726 4727} // end anonymous namespace 4728 4729// Notes the location of an overload candidate. 4730void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4731 std::string FnDesc; 4732 OverloadCandidateKind K = ClassifyOverloadCandidate(*this, Fn, FnDesc); 4733 Diag(Fn->getLocation(), diag::note_ovl_candidate) 4734 << (unsigned) K << FnDesc; 4735} 4736 4737/// Diagnoses an ambiguous conversion. The partial diagnostic is the 4738/// "lead" diagnostic; it will be given two arguments, the source and 4739/// target types of the conversion. 4740void Sema::DiagnoseAmbiguousConversion(const ImplicitConversionSequence &ICS, 4741 SourceLocation CaretLoc, 4742 const PartialDiagnostic &PDiag) { 4743 Diag(CaretLoc, PDiag) 4744 << ICS.Ambiguous.getFromType() << ICS.Ambiguous.getToType(); 4745 for (AmbiguousConversionSequence::const_iterator 4746 I = ICS.Ambiguous.begin(), E = ICS.Ambiguous.end(); I != E; ++I) { 4747 NoteOverloadCandidate(*I); 4748 } 4749} 4750 4751namespace { 4752 4753void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I) { 4754 const ImplicitConversionSequence &Conv = Cand->Conversions[I]; 4755 assert(Conv.isBad()); 4756 assert(Cand->Function && "for now, candidate must be a function"); 4757 FunctionDecl *Fn = Cand->Function; 4758 4759 // There's a conversion slot for the object argument if this is a 4760 // non-constructor method. Note that 'I' corresponds the 4761 // conversion-slot index. 4762 bool isObjectArgument = false; 4763 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { 4764 if (I == 0) 4765 isObjectArgument = true; 4766 else 4767 I--; 4768 } 4769 4770 std::string FnDesc; 4771 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4772 4773 Expr *FromExpr = Conv.Bad.FromExpr; 4774 QualType FromTy = Conv.Bad.getFromType(); 4775 QualType ToTy = Conv.Bad.getToType(); 4776 4777 if (FromTy == S.Context.OverloadTy) { 4778 assert(FromExpr && "overload set argument came from implicit argument?"); 4779 Expr *E = FromExpr->IgnoreParens(); 4780 if (isa<UnaryOperator>(E)) 4781 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 4782 DeclarationName Name = cast<OverloadExpr>(E)->getName(); 4783 4784 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) 4785 << (unsigned) FnKind << FnDesc 4786 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4787 << ToTy << Name << I+1; 4788 return; 4789 } 4790 4791 // Do some hand-waving analysis to see if the non-viability is due 4792 // to a qualifier mismatch. 4793 CanQualType CFromTy = S.Context.getCanonicalType(FromTy); 4794 CanQualType CToTy = S.Context.getCanonicalType(ToTy); 4795 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) 4796 CToTy = RT->getPointeeType(); 4797 else { 4798 // TODO: detect and diagnose the full richness of const mismatches. 4799 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) 4800 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) 4801 CFromTy = FromPT->getPointeeType(), CToTy = ToPT->getPointeeType(); 4802 } 4803 4804 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && 4805 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { 4806 // It is dumb that we have to do this here. 4807 while (isa<ArrayType>(CFromTy)) 4808 CFromTy = CFromTy->getAs<ArrayType>()->getElementType(); 4809 while (isa<ArrayType>(CToTy)) 4810 CToTy = CFromTy->getAs<ArrayType>()->getElementType(); 4811 4812 Qualifiers FromQs = CFromTy.getQualifiers(); 4813 Qualifiers ToQs = CToTy.getQualifiers(); 4814 4815 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { 4816 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) 4817 << (unsigned) FnKind << FnDesc 4818 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4819 << FromTy 4820 << FromQs.getAddressSpace() << ToQs.getAddressSpace() 4821 << (unsigned) isObjectArgument << I+1; 4822 return; 4823 } 4824 4825 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); 4826 assert(CVR && "unexpected qualifiers mismatch"); 4827 4828 if (isObjectArgument) { 4829 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) 4830 << (unsigned) FnKind << FnDesc 4831 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4832 << FromTy << (CVR - 1); 4833 } else { 4834 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) 4835 << (unsigned) FnKind << FnDesc 4836 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4837 << FromTy << (CVR - 1) << I+1; 4838 } 4839 return; 4840 } 4841 4842 // Diagnose references or pointers to incomplete types differently, 4843 // since it's far from impossible that the incompleteness triggered 4844 // the failure. 4845 QualType TempFromTy = FromTy.getNonReferenceType(); 4846 if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) 4847 TempFromTy = PTy->getPointeeType(); 4848 if (TempFromTy->isIncompleteType()) { 4849 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) 4850 << (unsigned) FnKind << FnDesc 4851 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4852 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4853 return; 4854 } 4855 4856 // TODO: specialize more based on the kind of mismatch 4857 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv) 4858 << (unsigned) FnKind << FnDesc 4859 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4860 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4861} 4862 4863void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, 4864 unsigned NumFormalArgs) { 4865 // TODO: treat calls to a missing default constructor as a special case 4866 4867 FunctionDecl *Fn = Cand->Function; 4868 const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); 4869 4870 unsigned MinParams = Fn->getMinRequiredArguments(); 4871 4872 // at least / at most / exactly 4873 unsigned mode, modeCount; 4874 if (NumFormalArgs < MinParams) { 4875 assert(Cand->FailureKind == ovl_fail_too_few_arguments); 4876 if (MinParams != FnTy->getNumArgs() || FnTy->isVariadic()) 4877 mode = 0; // "at least" 4878 else 4879 mode = 2; // "exactly" 4880 modeCount = MinParams; 4881 } else { 4882 assert(Cand->FailureKind == ovl_fail_too_many_arguments); 4883 if (MinParams != FnTy->getNumArgs()) 4884 mode = 1; // "at most" 4885 else 4886 mode = 2; // "exactly" 4887 modeCount = FnTy->getNumArgs(); 4888 } 4889 4890 std::string Description; 4891 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, Description); 4892 4893 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) 4894 << (unsigned) FnKind << Description << mode << modeCount << NumFormalArgs; 4895} 4896 4897/// Diagnose a failed template-argument deduction. 4898void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, 4899 Expr **Args, unsigned NumArgs) { 4900 FunctionDecl *Fn = Cand->Function; // pattern 4901 4902 TemplateParameter Param = TemplateParameter::getFromOpaqueValue( 4903 Cand->DeductionFailure.TemplateParameter); 4904 4905 switch (Cand->DeductionFailure.Result) { 4906 case Sema::TDK_Success: 4907 llvm_unreachable("TDK_success while diagnosing bad deduction"); 4908 4909 case Sema::TDK_Incomplete: { 4910 NamedDecl *ParamD; 4911 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || 4912 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || 4913 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); 4914 assert(ParamD && "no parameter found for incomplete deduction result"); 4915 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_incomplete_deduction) 4916 << ParamD->getDeclName(); 4917 return; 4918 } 4919 4920 // TODO: diagnose these individually, then kill off 4921 // note_ovl_candidate_bad_deduction, which is uselessly vague. 4922 case Sema::TDK_InstantiationDepth: 4923 case Sema::TDK_Inconsistent: 4924 case Sema::TDK_InconsistentQuals: 4925 case Sema::TDK_SubstitutionFailure: 4926 case Sema::TDK_NonDeducedMismatch: 4927 case Sema::TDK_TooManyArguments: 4928 case Sema::TDK_TooFewArguments: 4929 case Sema::TDK_InvalidExplicitArguments: 4930 case Sema::TDK_FailedOverloadResolution: 4931 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction); 4932 return; 4933 } 4934} 4935 4936/// Generates a 'note' diagnostic for an overload candidate. We've 4937/// already generated a primary error at the call site. 4938/// 4939/// It really does need to be a single diagnostic with its caret 4940/// pointed at the candidate declaration. Yes, this creates some 4941/// major challenges of technical writing. Yes, this makes pointing 4942/// out problems with specific arguments quite awkward. It's still 4943/// better than generating twenty screens of text for every failed 4944/// overload. 4945/// 4946/// It would be great to be able to express per-candidate problems 4947/// more richly for those diagnostic clients that cared, but we'd 4948/// still have to be just as careful with the default diagnostics. 4949void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, 4950 Expr **Args, unsigned NumArgs) { 4951 FunctionDecl *Fn = Cand->Function; 4952 4953 // Note deleted candidates, but only if they're viable. 4954 if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) { 4955 std::string FnDesc; 4956 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4957 4958 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) 4959 << FnKind << FnDesc << Fn->isDeleted(); 4960 return; 4961 } 4962 4963 // We don't really have anything else to say about viable candidates. 4964 if (Cand->Viable) { 4965 S.NoteOverloadCandidate(Fn); 4966 return; 4967 } 4968 4969 switch (Cand->FailureKind) { 4970 case ovl_fail_too_many_arguments: 4971 case ovl_fail_too_few_arguments: 4972 return DiagnoseArityMismatch(S, Cand, NumArgs); 4973 4974 case ovl_fail_bad_deduction: 4975 return DiagnoseBadDeduction(S, Cand, Args, NumArgs); 4976 4977 case ovl_fail_trivial_conversion: 4978 case ovl_fail_bad_final_conversion: 4979 case ovl_fail_final_conversion_not_exact: 4980 return S.NoteOverloadCandidate(Fn); 4981 4982 case ovl_fail_bad_conversion: { 4983 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); 4984 for (unsigned N = Cand->Conversions.size(); I != N; ++I) 4985 if (Cand->Conversions[I].isBad()) 4986 return DiagnoseBadConversion(S, Cand, I); 4987 4988 // FIXME: this currently happens when we're called from SemaInit 4989 // when user-conversion overload fails. Figure out how to handle 4990 // those conditions and diagnose them well. 4991 return S.NoteOverloadCandidate(Fn); 4992 } 4993 } 4994} 4995 4996void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 4997 // Desugar the type of the surrogate down to a function type, 4998 // retaining as many typedefs as possible while still showing 4999 // the function type (and, therefore, its parameter types). 5000 QualType FnType = Cand->Surrogate->getConversionType(); 5001 bool isLValueReference = false; 5002 bool isRValueReference = false; 5003 bool isPointer = false; 5004 if (const LValueReferenceType *FnTypeRef = 5005 FnType->getAs<LValueReferenceType>()) { 5006 FnType = FnTypeRef->getPointeeType(); 5007 isLValueReference = true; 5008 } else if (const RValueReferenceType *FnTypeRef = 5009 FnType->getAs<RValueReferenceType>()) { 5010 FnType = FnTypeRef->getPointeeType(); 5011 isRValueReference = true; 5012 } 5013 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 5014 FnType = FnTypePtr->getPointeeType(); 5015 isPointer = true; 5016 } 5017 // Desugar down to a function type. 5018 FnType = QualType(FnType->getAs<FunctionType>(), 0); 5019 // Reconstruct the pointer/reference as appropriate. 5020 if (isPointer) FnType = S.Context.getPointerType(FnType); 5021 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 5022 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 5023 5024 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 5025 << FnType; 5026} 5027 5028void NoteBuiltinOperatorCandidate(Sema &S, 5029 const char *Opc, 5030 SourceLocation OpLoc, 5031 OverloadCandidate *Cand) { 5032 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 5033 std::string TypeStr("operator"); 5034 TypeStr += Opc; 5035 TypeStr += "("; 5036 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 5037 if (Cand->Conversions.size() == 1) { 5038 TypeStr += ")"; 5039 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 5040 } else { 5041 TypeStr += ", "; 5042 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 5043 TypeStr += ")"; 5044 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 5045 } 5046} 5047 5048void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 5049 OverloadCandidate *Cand) { 5050 unsigned NoOperands = Cand->Conversions.size(); 5051 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 5052 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 5053 if (ICS.isBad()) break; // all meaningless after first invalid 5054 if (!ICS.isAmbiguous()) continue; 5055 5056 S.DiagnoseAmbiguousConversion(ICS, OpLoc, 5057 S.PDiag(diag::note_ambiguous_type_conversion)); 5058 } 5059} 5060 5061SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { 5062 if (Cand->Function) 5063 return Cand->Function->getLocation(); 5064 if (Cand->IsSurrogate) 5065 return Cand->Surrogate->getLocation(); 5066 return SourceLocation(); 5067} 5068 5069struct CompareOverloadCandidatesForDisplay { 5070 Sema &S; 5071 CompareOverloadCandidatesForDisplay(Sema &S) : S(S) {} 5072 5073 bool operator()(const OverloadCandidate *L, 5074 const OverloadCandidate *R) { 5075 // Fast-path this check. 5076 if (L == R) return false; 5077 5078 // Order first by viability. 5079 if (L->Viable) { 5080 if (!R->Viable) return true; 5081 5082 // TODO: introduce a tri-valued comparison for overload 5083 // candidates. Would be more worthwhile if we had a sort 5084 // that could exploit it. 5085 if (S.isBetterOverloadCandidate(*L, *R, SourceLocation())) return true; 5086 if (S.isBetterOverloadCandidate(*R, *L, SourceLocation())) return false; 5087 } else if (R->Viable) 5088 return false; 5089 5090 assert(L->Viable == R->Viable); 5091 5092 // Criteria by which we can sort non-viable candidates: 5093 if (!L->Viable) { 5094 // 1. Arity mismatches come after other candidates. 5095 if (L->FailureKind == ovl_fail_too_many_arguments || 5096 L->FailureKind == ovl_fail_too_few_arguments) 5097 return false; 5098 if (R->FailureKind == ovl_fail_too_many_arguments || 5099 R->FailureKind == ovl_fail_too_few_arguments) 5100 return true; 5101 5102 // 2. Bad conversions come first and are ordered by the number 5103 // of bad conversions and quality of good conversions. 5104 if (L->FailureKind == ovl_fail_bad_conversion) { 5105 if (R->FailureKind != ovl_fail_bad_conversion) 5106 return true; 5107 5108 // If there's any ordering between the defined conversions... 5109 // FIXME: this might not be transitive. 5110 assert(L->Conversions.size() == R->Conversions.size()); 5111 5112 int leftBetter = 0; 5113 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); 5114 for (unsigned E = L->Conversions.size(); I != E; ++I) { 5115 switch (S.CompareImplicitConversionSequences(L->Conversions[I], 5116 R->Conversions[I])) { 5117 case ImplicitConversionSequence::Better: 5118 leftBetter++; 5119 break; 5120 5121 case ImplicitConversionSequence::Worse: 5122 leftBetter--; 5123 break; 5124 5125 case ImplicitConversionSequence::Indistinguishable: 5126 break; 5127 } 5128 } 5129 if (leftBetter > 0) return true; 5130 if (leftBetter < 0) return false; 5131 5132 } else if (R->FailureKind == ovl_fail_bad_conversion) 5133 return false; 5134 5135 // TODO: others? 5136 } 5137 5138 // Sort everything else by location. 5139 SourceLocation LLoc = GetLocationForCandidate(L); 5140 SourceLocation RLoc = GetLocationForCandidate(R); 5141 5142 // Put candidates without locations (e.g. builtins) at the end. 5143 if (LLoc.isInvalid()) return false; 5144 if (RLoc.isInvalid()) return true; 5145 5146 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); 5147 } 5148}; 5149 5150/// CompleteNonViableCandidate - Normally, overload resolution only 5151/// computes up to the first 5152void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, 5153 Expr **Args, unsigned NumArgs) { 5154 assert(!Cand->Viable); 5155 5156 // Don't do anything on failures other than bad conversion. 5157 if (Cand->FailureKind != ovl_fail_bad_conversion) return; 5158 5159 // Skip forward to the first bad conversion. 5160 unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); 5161 unsigned ConvCount = Cand->Conversions.size(); 5162 while (true) { 5163 assert(ConvIdx != ConvCount && "no bad conversion in candidate"); 5164 ConvIdx++; 5165 if (Cand->Conversions[ConvIdx - 1].isBad()) 5166 break; 5167 } 5168 5169 if (ConvIdx == ConvCount) 5170 return; 5171 5172 assert(!Cand->Conversions[ConvIdx].isInitialized() && 5173 "remaining conversion is initialized?"); 5174 5175 // FIXME: this should probably be preserved from the overload 5176 // operation somehow. 5177 bool SuppressUserConversions = false; 5178 5179 const FunctionProtoType* Proto; 5180 unsigned ArgIdx = ConvIdx; 5181 5182 if (Cand->IsSurrogate) { 5183 QualType ConvType 5184 = Cand->Surrogate->getConversionType().getNonReferenceType(); 5185 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5186 ConvType = ConvPtrType->getPointeeType(); 5187 Proto = ConvType->getAs<FunctionProtoType>(); 5188 ArgIdx--; 5189 } else if (Cand->Function) { 5190 Proto = Cand->Function->getType()->getAs<FunctionProtoType>(); 5191 if (isa<CXXMethodDecl>(Cand->Function) && 5192 !isa<CXXConstructorDecl>(Cand->Function)) 5193 ArgIdx--; 5194 } else { 5195 // Builtin binary operator with a bad first conversion. 5196 assert(ConvCount <= 3); 5197 for (; ConvIdx != ConvCount; ++ConvIdx) 5198 Cand->Conversions[ConvIdx] 5199 = TryCopyInitialization(S, Args[ConvIdx], 5200 Cand->BuiltinTypes.ParamTypes[ConvIdx], 5201 SuppressUserConversions, 5202 /*InOverloadResolution*/ true); 5203 return; 5204 } 5205 5206 // Fill in the rest of the conversions. 5207 unsigned NumArgsInProto = Proto->getNumArgs(); 5208 for (; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { 5209 if (ArgIdx < NumArgsInProto) 5210 Cand->Conversions[ConvIdx] 5211 = TryCopyInitialization(S, Args[ArgIdx], Proto->getArgType(ArgIdx), 5212 SuppressUserConversions, 5213 /*InOverloadResolution=*/true); 5214 else 5215 Cand->Conversions[ConvIdx].setEllipsis(); 5216 } 5217} 5218 5219} // end anonymous namespace 5220 5221/// PrintOverloadCandidates - When overload resolution fails, prints 5222/// diagnostic messages containing the candidates in the candidate 5223/// set. 5224void 5225Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 5226 OverloadCandidateDisplayKind OCD, 5227 Expr **Args, unsigned NumArgs, 5228 const char *Opc, 5229 SourceLocation OpLoc) { 5230 // Sort the candidates by viability and position. Sorting directly would 5231 // be prohibitive, so we make a set of pointers and sort those. 5232 llvm::SmallVector<OverloadCandidate*, 32> Cands; 5233 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 5234 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 5235 LastCand = CandidateSet.end(); 5236 Cand != LastCand; ++Cand) { 5237 if (Cand->Viable) 5238 Cands.push_back(Cand); 5239 else if (OCD == OCD_AllCandidates) { 5240 CompleteNonViableCandidate(*this, Cand, Args, NumArgs); 5241 Cands.push_back(Cand); 5242 } 5243 } 5244 5245 std::sort(Cands.begin(), Cands.end(), 5246 CompareOverloadCandidatesForDisplay(*this)); 5247 5248 bool ReportedAmbiguousConversions = false; 5249 5250 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 5251 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 5252 OverloadCandidate *Cand = *I; 5253 5254 if (Cand->Function) 5255 NoteFunctionCandidate(*this, Cand, Args, NumArgs); 5256 else if (Cand->IsSurrogate) 5257 NoteSurrogateCandidate(*this, Cand); 5258 5259 // This a builtin candidate. We do not, in general, want to list 5260 // every possible builtin candidate. 5261 else if (Cand->Viable) { 5262 // Generally we only see ambiguities including viable builtin 5263 // operators if overload resolution got screwed up by an 5264 // ambiguous user-defined conversion. 5265 // 5266 // FIXME: It's quite possible for different conversions to see 5267 // different ambiguities, though. 5268 if (!ReportedAmbiguousConversions) { 5269 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 5270 ReportedAmbiguousConversions = true; 5271 } 5272 5273 // If this is a viable builtin, print it. 5274 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 5275 } 5276 } 5277} 5278 5279static bool CheckUnresolvedAccess(Sema &S, OverloadExpr *E, DeclAccessPair D) { 5280 if (isa<UnresolvedLookupExpr>(E)) 5281 return S.CheckUnresolvedLookupAccess(cast<UnresolvedLookupExpr>(E), D); 5282 5283 return S.CheckUnresolvedMemberAccess(cast<UnresolvedMemberExpr>(E), D); 5284} 5285 5286/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 5287/// an overloaded function (C++ [over.over]), where @p From is an 5288/// expression with overloaded function type and @p ToType is the type 5289/// we're trying to resolve to. For example: 5290/// 5291/// @code 5292/// int f(double); 5293/// int f(int); 5294/// 5295/// int (*pfd)(double) = f; // selects f(double) 5296/// @endcode 5297/// 5298/// This routine returns the resulting FunctionDecl if it could be 5299/// resolved, and NULL otherwise. When @p Complain is true, this 5300/// routine will emit diagnostics if there is an error. 5301FunctionDecl * 5302Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 5303 bool Complain, 5304 DeclAccessPair &FoundResult) { 5305 QualType FunctionType = ToType; 5306 bool IsMember = false; 5307 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 5308 FunctionType = ToTypePtr->getPointeeType(); 5309 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 5310 FunctionType = ToTypeRef->getPointeeType(); 5311 else if (const MemberPointerType *MemTypePtr = 5312 ToType->getAs<MemberPointerType>()) { 5313 FunctionType = MemTypePtr->getPointeeType(); 5314 IsMember = true; 5315 } 5316 5317 // C++ [over.over]p1: 5318 // [...] [Note: any redundant set of parentheses surrounding the 5319 // overloaded function name is ignored (5.1). ] 5320 // C++ [over.over]p1: 5321 // [...] The overloaded function name can be preceded by the & 5322 // operator. 5323 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5324 TemplateArgumentListInfo ETABuffer, *ExplicitTemplateArgs = 0; 5325 if (OvlExpr->hasExplicitTemplateArgs()) { 5326 OvlExpr->getExplicitTemplateArgs().copyInto(ETABuffer); 5327 ExplicitTemplateArgs = &ETABuffer; 5328 } 5329 5330 // We expect a pointer or reference to function, or a function pointer. 5331 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 5332 if (!FunctionType->isFunctionType()) { 5333 if (Complain) 5334 Diag(From->getLocStart(), diag::err_addr_ovl_not_func_ptrref) 5335 << OvlExpr->getName() << ToType; 5336 5337 return 0; 5338 } 5339 5340 assert(From->getType() == Context.OverloadTy); 5341 5342 // Look through all of the overloaded functions, searching for one 5343 // whose type matches exactly. 5344 llvm::SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; 5345 llvm::SmallVector<FunctionDecl *, 4> NonMatches; 5346 5347 bool FoundNonTemplateFunction = false; 5348 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5349 E = OvlExpr->decls_end(); I != E; ++I) { 5350 // Look through any using declarations to find the underlying function. 5351 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 5352 5353 // C++ [over.over]p3: 5354 // Non-member functions and static member functions match 5355 // targets of type "pointer-to-function" or "reference-to-function." 5356 // Nonstatic member functions match targets of 5357 // type "pointer-to-member-function." 5358 // Note that according to DR 247, the containing class does not matter. 5359 5360 if (FunctionTemplateDecl *FunctionTemplate 5361 = dyn_cast<FunctionTemplateDecl>(Fn)) { 5362 if (CXXMethodDecl *Method 5363 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 5364 // Skip non-static function templates when converting to pointer, and 5365 // static when converting to member pointer. 5366 if (Method->isStatic() == IsMember) 5367 continue; 5368 } else if (IsMember) 5369 continue; 5370 5371 // C++ [over.over]p2: 5372 // If the name is a function template, template argument deduction is 5373 // done (14.8.2.2), and if the argument deduction succeeds, the 5374 // resulting template argument list is used to generate a single 5375 // function template specialization, which is added to the set of 5376 // overloaded functions considered. 5377 // FIXME: We don't really want to build the specialization here, do we? 5378 FunctionDecl *Specialization = 0; 5379 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5380 if (TemplateDeductionResult Result 5381 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 5382 FunctionType, Specialization, Info)) { 5383 // FIXME: make a note of the failed deduction for diagnostics. 5384 (void)Result; 5385 } else { 5386 // FIXME: If the match isn't exact, shouldn't we just drop this as 5387 // a candidate? Find a testcase before changing the code. 5388 assert(FunctionType 5389 == Context.getCanonicalType(Specialization->getType())); 5390 Matches.push_back(std::make_pair(I.getPair(), 5391 cast<FunctionDecl>(Specialization->getCanonicalDecl()))); 5392 } 5393 5394 continue; 5395 } 5396 5397 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 5398 // Skip non-static functions when converting to pointer, and static 5399 // when converting to member pointer. 5400 if (Method->isStatic() == IsMember) 5401 continue; 5402 5403 // If we have explicit template arguments, skip non-templates. 5404 if (OvlExpr->hasExplicitTemplateArgs()) 5405 continue; 5406 } else if (IsMember) 5407 continue; 5408 5409 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 5410 QualType ResultTy; 5411 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 5412 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 5413 ResultTy)) { 5414 Matches.push_back(std::make_pair(I.getPair(), 5415 cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); 5416 FoundNonTemplateFunction = true; 5417 } 5418 } 5419 } 5420 5421 // If there were 0 or 1 matches, we're done. 5422 if (Matches.empty()) { 5423 if (Complain) { 5424 Diag(From->getLocStart(), diag::err_addr_ovl_no_viable) 5425 << OvlExpr->getName() << FunctionType; 5426 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5427 E = OvlExpr->decls_end(); 5428 I != E; ++I) 5429 if (FunctionDecl *F = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) 5430 NoteOverloadCandidate(F); 5431 } 5432 5433 return 0; 5434 } else if (Matches.size() == 1) { 5435 FunctionDecl *Result = Matches[0].second; 5436 FoundResult = Matches[0].first; 5437 MarkDeclarationReferenced(From->getLocStart(), Result); 5438 if (Complain) 5439 CheckAddressOfMemberAccess(OvlExpr, Matches[0].first); 5440 return Result; 5441 } 5442 5443 // C++ [over.over]p4: 5444 // If more than one function is selected, [...] 5445 if (!FoundNonTemplateFunction) { 5446 // [...] and any given function template specialization F1 is 5447 // eliminated if the set contains a second function template 5448 // specialization whose function template is more specialized 5449 // than the function template of F1 according to the partial 5450 // ordering rules of 14.5.5.2. 5451 5452 // The algorithm specified above is quadratic. We instead use a 5453 // two-pass algorithm (similar to the one used to identify the 5454 // best viable function in an overload set) that identifies the 5455 // best function template (if it exists). 5456 5457 UnresolvedSet<4> MatchesCopy; // TODO: avoid! 5458 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5459 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); 5460 5461 UnresolvedSetIterator Result = 5462 getMostSpecialized(MatchesCopy.begin(), MatchesCopy.end(), 5463 TPOC_Other, From->getLocStart(), 5464 PDiag(), 5465 PDiag(diag::err_addr_ovl_ambiguous) 5466 << Matches[0].second->getDeclName(), 5467 PDiag(diag::note_ovl_candidate) 5468 << (unsigned) oc_function_template); 5469 assert(Result != MatchesCopy.end() && "no most-specialized template"); 5470 MarkDeclarationReferenced(From->getLocStart(), *Result); 5471 FoundResult = Matches[Result - MatchesCopy.begin()].first; 5472 if (Complain) 5473 CheckUnresolvedAccess(*this, OvlExpr, FoundResult); 5474 return cast<FunctionDecl>(*Result); 5475 } 5476 5477 // [...] any function template specializations in the set are 5478 // eliminated if the set also contains a non-template function, [...] 5479 for (unsigned I = 0, N = Matches.size(); I != N; ) { 5480 if (Matches[I].second->getPrimaryTemplate() == 0) 5481 ++I; 5482 else { 5483 Matches[I] = Matches[--N]; 5484 Matches.set_size(N); 5485 } 5486 } 5487 5488 // [...] After such eliminations, if any, there shall remain exactly one 5489 // selected function. 5490 if (Matches.size() == 1) { 5491 MarkDeclarationReferenced(From->getLocStart(), Matches[0].second); 5492 FoundResult = Matches[0].first; 5493 if (Complain) 5494 CheckUnresolvedAccess(*this, OvlExpr, Matches[0].first); 5495 return cast<FunctionDecl>(Matches[0].second); 5496 } 5497 5498 // FIXME: We should probably return the same thing that BestViableFunction 5499 // returns (even if we issue the diagnostics here). 5500 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 5501 << Matches[0].second->getDeclName(); 5502 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5503 NoteOverloadCandidate(Matches[I].second); 5504 return 0; 5505} 5506 5507/// \brief Given an expression that refers to an overloaded function, try to 5508/// resolve that overloaded function expression down to a single function. 5509/// 5510/// This routine can only resolve template-ids that refer to a single function 5511/// template, where that template-id refers to a single template whose template 5512/// arguments are either provided by the template-id or have defaults, 5513/// as described in C++0x [temp.arg.explicit]p3. 5514FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 5515 // C++ [over.over]p1: 5516 // [...] [Note: any redundant set of parentheses surrounding the 5517 // overloaded function name is ignored (5.1). ] 5518 // C++ [over.over]p1: 5519 // [...] The overloaded function name can be preceded by the & 5520 // operator. 5521 5522 if (From->getType() != Context.OverloadTy) 5523 return 0; 5524 5525 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5526 5527 // If we didn't actually find any template-ids, we're done. 5528 if (!OvlExpr->hasExplicitTemplateArgs()) 5529 return 0; 5530 5531 TemplateArgumentListInfo ExplicitTemplateArgs; 5532 OvlExpr->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 5533 5534 // Look through all of the overloaded functions, searching for one 5535 // whose type matches exactly. 5536 FunctionDecl *Matched = 0; 5537 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5538 E = OvlExpr->decls_end(); I != E; ++I) { 5539 // C++0x [temp.arg.explicit]p3: 5540 // [...] In contexts where deduction is done and fails, or in contexts 5541 // where deduction is not done, if a template argument list is 5542 // specified and it, along with any default template arguments, 5543 // identifies a single function template specialization, then the 5544 // template-id is an lvalue for the function template specialization. 5545 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 5546 5547 // C++ [over.over]p2: 5548 // If the name is a function template, template argument deduction is 5549 // done (14.8.2.2), and if the argument deduction succeeds, the 5550 // resulting template argument list is used to generate a single 5551 // function template specialization, which is added to the set of 5552 // overloaded functions considered. 5553 FunctionDecl *Specialization = 0; 5554 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5555 if (TemplateDeductionResult Result 5556 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 5557 Specialization, Info)) { 5558 // FIXME: make a note of the failed deduction for diagnostics. 5559 (void)Result; 5560 continue; 5561 } 5562 5563 // Multiple matches; we can't resolve to a single declaration. 5564 if (Matched) 5565 return 0; 5566 5567 Matched = Specialization; 5568 } 5569 5570 return Matched; 5571} 5572 5573/// \brief Add a single candidate to the overload set. 5574static void AddOverloadedCallCandidate(Sema &S, 5575 DeclAccessPair FoundDecl, 5576 const TemplateArgumentListInfo *ExplicitTemplateArgs, 5577 Expr **Args, unsigned NumArgs, 5578 OverloadCandidateSet &CandidateSet, 5579 bool PartialOverloading) { 5580 NamedDecl *Callee = FoundDecl.getDecl(); 5581 if (isa<UsingShadowDecl>(Callee)) 5582 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 5583 5584 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 5585 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 5586 S.AddOverloadCandidate(Func, FoundDecl, Args, NumArgs, CandidateSet, 5587 false, PartialOverloading); 5588 return; 5589 } 5590 5591 if (FunctionTemplateDecl *FuncTemplate 5592 = dyn_cast<FunctionTemplateDecl>(Callee)) { 5593 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, 5594 ExplicitTemplateArgs, 5595 Args, NumArgs, CandidateSet); 5596 return; 5597 } 5598 5599 assert(false && "unhandled case in overloaded call candidate"); 5600 5601 // do nothing? 5602} 5603 5604/// \brief Add the overload candidates named by callee and/or found by argument 5605/// dependent lookup to the given overload set. 5606void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 5607 Expr **Args, unsigned NumArgs, 5608 OverloadCandidateSet &CandidateSet, 5609 bool PartialOverloading) { 5610 5611#ifndef NDEBUG 5612 // Verify that ArgumentDependentLookup is consistent with the rules 5613 // in C++0x [basic.lookup.argdep]p3: 5614 // 5615 // Let X be the lookup set produced by unqualified lookup (3.4.1) 5616 // and let Y be the lookup set produced by argument dependent 5617 // lookup (defined as follows). If X contains 5618 // 5619 // -- a declaration of a class member, or 5620 // 5621 // -- a block-scope function declaration that is not a 5622 // using-declaration, or 5623 // 5624 // -- a declaration that is neither a function or a function 5625 // template 5626 // 5627 // then Y is empty. 5628 5629 if (ULE->requiresADL()) { 5630 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5631 E = ULE->decls_end(); I != E; ++I) { 5632 assert(!(*I)->getDeclContext()->isRecord()); 5633 assert(isa<UsingShadowDecl>(*I) || 5634 !(*I)->getDeclContext()->isFunctionOrMethod()); 5635 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 5636 } 5637 } 5638#endif 5639 5640 // It would be nice to avoid this copy. 5641 TemplateArgumentListInfo TABuffer; 5642 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5643 if (ULE->hasExplicitTemplateArgs()) { 5644 ULE->copyTemplateArgumentsInto(TABuffer); 5645 ExplicitTemplateArgs = &TABuffer; 5646 } 5647 5648 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5649 E = ULE->decls_end(); I != E; ++I) 5650 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, 5651 Args, NumArgs, CandidateSet, 5652 PartialOverloading); 5653 5654 if (ULE->requiresADL()) 5655 AddArgumentDependentLookupCandidates(ULE->getName(), /*Operator*/ false, 5656 Args, NumArgs, 5657 ExplicitTemplateArgs, 5658 CandidateSet, 5659 PartialOverloading); 5660} 5661 5662static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 5663 Expr **Args, unsigned NumArgs) { 5664 Fn->Destroy(SemaRef.Context); 5665 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5666 Args[Arg]->Destroy(SemaRef.Context); 5667 return SemaRef.ExprError(); 5668} 5669 5670/// Attempts to recover from a call where no functions were found. 5671/// 5672/// Returns true if new candidates were found. 5673static Sema::OwningExprResult 5674BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, 5675 UnresolvedLookupExpr *ULE, 5676 SourceLocation LParenLoc, 5677 Expr **Args, unsigned NumArgs, 5678 SourceLocation *CommaLocs, 5679 SourceLocation RParenLoc) { 5680 5681 CXXScopeSpec SS; 5682 if (ULE->getQualifier()) { 5683 SS.setScopeRep(ULE->getQualifier()); 5684 SS.setRange(ULE->getQualifierRange()); 5685 } 5686 5687 TemplateArgumentListInfo TABuffer; 5688 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5689 if (ULE->hasExplicitTemplateArgs()) { 5690 ULE->copyTemplateArgumentsInto(TABuffer); 5691 ExplicitTemplateArgs = &TABuffer; 5692 } 5693 5694 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 5695 Sema::LookupOrdinaryName); 5696 if (SemaRef.DiagnoseEmptyLookup(S, SS, R)) 5697 return Destroy(SemaRef, Fn, Args, NumArgs); 5698 5699 assert(!R.empty() && "lookup results empty despite recovery"); 5700 5701 // Build an implicit member call if appropriate. Just drop the 5702 // casts and such from the call, we don't really care. 5703 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 5704 if ((*R.begin())->isCXXClassMember()) 5705 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 5706 else if (ExplicitTemplateArgs) 5707 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 5708 else 5709 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 5710 5711 if (NewFn.isInvalid()) 5712 return Destroy(SemaRef, Fn, Args, NumArgs); 5713 5714 Fn->Destroy(SemaRef.Context); 5715 5716 // This shouldn't cause an infinite loop because we're giving it 5717 // an expression with non-empty lookup results, which should never 5718 // end up here. 5719 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 5720 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 5721 CommaLocs, RParenLoc); 5722} 5723 5724/// ResolveOverloadedCallFn - Given the call expression that calls Fn 5725/// (which eventually refers to the declaration Func) and the call 5726/// arguments Args/NumArgs, attempt to resolve the function call down 5727/// to a specific function. If overload resolution succeeds, returns 5728/// the function declaration produced by overload 5729/// resolution. Otherwise, emits diagnostics, deletes all of the 5730/// arguments and Fn, and returns NULL. 5731Sema::OwningExprResult 5732Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, 5733 SourceLocation LParenLoc, 5734 Expr **Args, unsigned NumArgs, 5735 SourceLocation *CommaLocs, 5736 SourceLocation RParenLoc) { 5737#ifndef NDEBUG 5738 if (ULE->requiresADL()) { 5739 // To do ADL, we must have found an unqualified name. 5740 assert(!ULE->getQualifier() && "qualified name with ADL"); 5741 5742 // We don't perform ADL for implicit declarations of builtins. 5743 // Verify that this was correctly set up. 5744 FunctionDecl *F; 5745 if (ULE->decls_begin() + 1 == ULE->decls_end() && 5746 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 5747 F->getBuiltinID() && F->isImplicit()) 5748 assert(0 && "performing ADL for builtin"); 5749 5750 // We don't perform ADL in C. 5751 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 5752 } 5753#endif 5754 5755 OverloadCandidateSet CandidateSet(Fn->getExprLoc()); 5756 5757 // Add the functions denoted by the callee to the set of candidate 5758 // functions, including those from argument-dependent lookup. 5759 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 5760 5761 // If we found nothing, try to recover. 5762 // AddRecoveryCallCandidates diagnoses the error itself, so we just 5763 // bailout out if it fails. 5764 if (CandidateSet.empty()) 5765 return BuildRecoveryCallExpr(*this, S, Fn, ULE, LParenLoc, Args, NumArgs, 5766 CommaLocs, RParenLoc); 5767 5768 OverloadCandidateSet::iterator Best; 5769 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 5770 case OR_Success: { 5771 FunctionDecl *FDecl = Best->Function; 5772 CheckUnresolvedLookupAccess(ULE, Best->FoundDecl); 5773 Fn = FixOverloadedFunctionReference(Fn, Best->FoundDecl, FDecl); 5774 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 5775 } 5776 5777 case OR_No_Viable_Function: 5778 Diag(Fn->getSourceRange().getBegin(), 5779 diag::err_ovl_no_viable_function_in_call) 5780 << ULE->getName() << Fn->getSourceRange(); 5781 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5782 break; 5783 5784 case OR_Ambiguous: 5785 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 5786 << ULE->getName() << Fn->getSourceRange(); 5787 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 5788 break; 5789 5790 case OR_Deleted: 5791 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 5792 << Best->Function->isDeleted() 5793 << ULE->getName() 5794 << Fn->getSourceRange(); 5795 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5796 break; 5797 } 5798 5799 // Overload resolution failed. Destroy all of the subexpressions and 5800 // return NULL. 5801 Fn->Destroy(Context); 5802 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5803 Args[Arg]->Destroy(Context); 5804 return ExprError(); 5805} 5806 5807static bool IsOverloaded(const UnresolvedSetImpl &Functions) { 5808 return Functions.size() > 1 || 5809 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 5810} 5811 5812/// \brief Create a unary operation that may resolve to an overloaded 5813/// operator. 5814/// 5815/// \param OpLoc The location of the operator itself (e.g., '*'). 5816/// 5817/// \param OpcIn The UnaryOperator::Opcode that describes this 5818/// operator. 5819/// 5820/// \param Functions The set of non-member functions that will be 5821/// considered by overload resolution. The caller needs to build this 5822/// set based on the context using, e.g., 5823/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5824/// set should not contain any member functions; those will be added 5825/// by CreateOverloadedUnaryOp(). 5826/// 5827/// \param input The input argument. 5828Sema::OwningExprResult 5829Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn, 5830 const UnresolvedSetImpl &Fns, 5831 ExprArg input) { 5832 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 5833 Expr *Input = (Expr *)input.get(); 5834 5835 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 5836 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 5837 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5838 5839 Expr *Args[2] = { Input, 0 }; 5840 unsigned NumArgs = 1; 5841 5842 // For post-increment and post-decrement, add the implicit '0' as 5843 // the second argument, so that we know this is a post-increment or 5844 // post-decrement. 5845 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 5846 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 5847 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 5848 SourceLocation()); 5849 NumArgs = 2; 5850 } 5851 5852 if (Input->isTypeDependent()) { 5853 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 5854 UnresolvedLookupExpr *Fn 5855 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 5856 0, SourceRange(), OpName, OpLoc, 5857 /*ADL*/ true, IsOverloaded(Fns)); 5858 Fn->addDecls(Fns.begin(), Fns.end()); 5859 5860 input.release(); 5861 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 5862 &Args[0], NumArgs, 5863 Context.DependentTy, 5864 OpLoc)); 5865 } 5866 5867 // Build an empty overload set. 5868 OverloadCandidateSet CandidateSet(OpLoc); 5869 5870 // Add the candidates from the given function set. 5871 AddFunctionCandidates(Fns, &Args[0], NumArgs, CandidateSet, false); 5872 5873 // Add operator candidates that are member functions. 5874 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5875 5876 // Add candidates from ADL. 5877 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 5878 Args, NumArgs, 5879 /*ExplicitTemplateArgs*/ 0, 5880 CandidateSet); 5881 5882 // Add builtin operator candidates. 5883 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5884 5885 // Perform overload resolution. 5886 OverloadCandidateSet::iterator Best; 5887 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5888 case OR_Success: { 5889 // We found a built-in operator or an overloaded operator. 5890 FunctionDecl *FnDecl = Best->Function; 5891 5892 if (FnDecl) { 5893 // We matched an overloaded operator. Build a call to that 5894 // operator. 5895 5896 // Convert the arguments. 5897 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 5898 CheckMemberOperatorAccess(OpLoc, Args[0], 0, Best->FoundDecl); 5899 5900 if (PerformObjectArgumentInitialization(Input, /*Qualifier=*/0, 5901 Best->FoundDecl, Method)) 5902 return ExprError(); 5903 } else { 5904 // Convert the arguments. 5905 OwningExprResult InputInit 5906 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 5907 FnDecl->getParamDecl(0)), 5908 SourceLocation(), 5909 move(input)); 5910 if (InputInit.isInvalid()) 5911 return ExprError(); 5912 5913 input = move(InputInit); 5914 Input = (Expr *)input.get(); 5915 } 5916 5917 // Determine the result type 5918 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 5919 5920 // Build the actual expression node. 5921 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5922 SourceLocation()); 5923 UsualUnaryConversions(FnExpr); 5924 5925 input.release(); 5926 Args[0] = Input; 5927 ExprOwningPtr<CallExpr> TheCall(this, 5928 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 5929 Args, NumArgs, ResultTy, OpLoc)); 5930 5931 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 5932 FnDecl)) 5933 return ExprError(); 5934 5935 return MaybeBindToTemporary(TheCall.release()); 5936 } else { 5937 // We matched a built-in operator. Convert the arguments, then 5938 // break out so that we will build the appropriate built-in 5939 // operator node. 5940 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 5941 Best->Conversions[0], AA_Passing)) 5942 return ExprError(); 5943 5944 break; 5945 } 5946 } 5947 5948 case OR_No_Viable_Function: 5949 // No viable function; fall through to handling this as a 5950 // built-in operator, which will produce an error message for us. 5951 break; 5952 5953 case OR_Ambiguous: 5954 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5955 << UnaryOperator::getOpcodeStr(Opc) 5956 << Input->getSourceRange(); 5957 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs, 5958 UnaryOperator::getOpcodeStr(Opc), OpLoc); 5959 return ExprError(); 5960 5961 case OR_Deleted: 5962 Diag(OpLoc, diag::err_ovl_deleted_oper) 5963 << Best->Function->isDeleted() 5964 << UnaryOperator::getOpcodeStr(Opc) 5965 << Input->getSourceRange(); 5966 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5967 return ExprError(); 5968 } 5969 5970 // Either we found no viable overloaded operator or we matched a 5971 // built-in operator. In either case, fall through to trying to 5972 // build a built-in operation. 5973 input.release(); 5974 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 5975} 5976 5977/// \brief Create a binary operation that may resolve to an overloaded 5978/// operator. 5979/// 5980/// \param OpLoc The location of the operator itself (e.g., '+'). 5981/// 5982/// \param OpcIn The BinaryOperator::Opcode that describes this 5983/// operator. 5984/// 5985/// \param Functions The set of non-member functions that will be 5986/// considered by overload resolution. The caller needs to build this 5987/// set based on the context using, e.g., 5988/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5989/// set should not contain any member functions; those will be added 5990/// by CreateOverloadedBinOp(). 5991/// 5992/// \param LHS Left-hand argument. 5993/// \param RHS Right-hand argument. 5994Sema::OwningExprResult 5995Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 5996 unsigned OpcIn, 5997 const UnresolvedSetImpl &Fns, 5998 Expr *LHS, Expr *RHS) { 5999 Expr *Args[2] = { LHS, RHS }; 6000 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 6001 6002 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 6003 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 6004 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 6005 6006 // If either side is type-dependent, create an appropriate dependent 6007 // expression. 6008 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6009 if (Fns.empty()) { 6010 // If there are no functions to store, just build a dependent 6011 // BinaryOperator or CompoundAssignment. 6012 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 6013 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 6014 Context.DependentTy, OpLoc)); 6015 6016 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 6017 Context.DependentTy, 6018 Context.DependentTy, 6019 Context.DependentTy, 6020 OpLoc)); 6021 } 6022 6023 // FIXME: save results of ADL from here? 6024 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6025 UnresolvedLookupExpr *Fn 6026 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6027 0, SourceRange(), OpName, OpLoc, 6028 /*ADL*/ true, IsOverloaded(Fns)); 6029 6030 Fn->addDecls(Fns.begin(), Fns.end()); 6031 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6032 Args, 2, 6033 Context.DependentTy, 6034 OpLoc)); 6035 } 6036 6037 // If this is the .* operator, which is not overloadable, just 6038 // create a built-in binary operator. 6039 if (Opc == BinaryOperator::PtrMemD) 6040 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6041 6042 // If this is the assignment operator, we only perform overload resolution 6043 // if the left-hand side is a class or enumeration type. This is actually 6044 // a hack. The standard requires that we do overload resolution between the 6045 // various built-in candidates, but as DR507 points out, this can lead to 6046 // problems. So we do it this way, which pretty much follows what GCC does. 6047 // Note that we go the traditional code path for compound assignment forms. 6048 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 6049 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6050 6051 // Build an empty overload set. 6052 OverloadCandidateSet CandidateSet(OpLoc); 6053 6054 // Add the candidates from the given function set. 6055 AddFunctionCandidates(Fns, Args, 2, CandidateSet, false); 6056 6057 // Add operator candidates that are member functions. 6058 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6059 6060 // Add candidates from ADL. 6061 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6062 Args, 2, 6063 /*ExplicitTemplateArgs*/ 0, 6064 CandidateSet); 6065 6066 // Add builtin operator candidates. 6067 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6068 6069 // Perform overload resolution. 6070 OverloadCandidateSet::iterator Best; 6071 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6072 case OR_Success: { 6073 // We found a built-in operator or an overloaded operator. 6074 FunctionDecl *FnDecl = Best->Function; 6075 6076 if (FnDecl) { 6077 // We matched an overloaded operator. Build a call to that 6078 // operator. 6079 6080 // Convert the arguments. 6081 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6082 // Best->Access is only meaningful for class members. 6083 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); 6084 6085 OwningExprResult Arg1 6086 = PerformCopyInitialization( 6087 InitializedEntity::InitializeParameter( 6088 FnDecl->getParamDecl(0)), 6089 SourceLocation(), 6090 Owned(Args[1])); 6091 if (Arg1.isInvalid()) 6092 return ExprError(); 6093 6094 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6095 Best->FoundDecl, Method)) 6096 return ExprError(); 6097 6098 Args[1] = RHS = Arg1.takeAs<Expr>(); 6099 } else { 6100 // Convert the arguments. 6101 OwningExprResult Arg0 6102 = PerformCopyInitialization( 6103 InitializedEntity::InitializeParameter( 6104 FnDecl->getParamDecl(0)), 6105 SourceLocation(), 6106 Owned(Args[0])); 6107 if (Arg0.isInvalid()) 6108 return ExprError(); 6109 6110 OwningExprResult Arg1 6111 = PerformCopyInitialization( 6112 InitializedEntity::InitializeParameter( 6113 FnDecl->getParamDecl(1)), 6114 SourceLocation(), 6115 Owned(Args[1])); 6116 if (Arg1.isInvalid()) 6117 return ExprError(); 6118 Args[0] = LHS = Arg0.takeAs<Expr>(); 6119 Args[1] = RHS = Arg1.takeAs<Expr>(); 6120 } 6121 6122 // Determine the result type 6123 QualType ResultTy 6124 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6125 ResultTy = ResultTy.getNonReferenceType(); 6126 6127 // Build the actual expression node. 6128 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6129 OpLoc); 6130 UsualUnaryConversions(FnExpr); 6131 6132 ExprOwningPtr<CXXOperatorCallExpr> 6133 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6134 Args, 2, ResultTy, 6135 OpLoc)); 6136 6137 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6138 FnDecl)) 6139 return ExprError(); 6140 6141 return MaybeBindToTemporary(TheCall.release()); 6142 } else { 6143 // We matched a built-in operator. Convert the arguments, then 6144 // break out so that we will build the appropriate built-in 6145 // operator node. 6146 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6147 Best->Conversions[0], AA_Passing) || 6148 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6149 Best->Conversions[1], AA_Passing)) 6150 return ExprError(); 6151 6152 break; 6153 } 6154 } 6155 6156 case OR_No_Viable_Function: { 6157 // C++ [over.match.oper]p9: 6158 // If the operator is the operator , [...] and there are no 6159 // viable functions, then the operator is assumed to be the 6160 // built-in operator and interpreted according to clause 5. 6161 if (Opc == BinaryOperator::Comma) 6162 break; 6163 6164 // For class as left operand for assignment or compound assigment operator 6165 // do not fall through to handling in built-in, but report that no overloaded 6166 // assignment operator found 6167 OwningExprResult Result = ExprError(); 6168 if (Args[0]->getType()->isRecordType() && 6169 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 6170 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6171 << BinaryOperator::getOpcodeStr(Opc) 6172 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6173 } else { 6174 // No viable function; try to create a built-in operation, which will 6175 // produce an error. Then, show the non-viable candidates. 6176 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6177 } 6178 assert(Result.isInvalid() && 6179 "C++ binary operator overloading is missing candidates!"); 6180 if (Result.isInvalid()) 6181 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6182 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6183 return move(Result); 6184 } 6185 6186 case OR_Ambiguous: 6187 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6188 << BinaryOperator::getOpcodeStr(Opc) 6189 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6190 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6191 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6192 return ExprError(); 6193 6194 case OR_Deleted: 6195 Diag(OpLoc, diag::err_ovl_deleted_oper) 6196 << Best->Function->isDeleted() 6197 << BinaryOperator::getOpcodeStr(Opc) 6198 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6199 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2); 6200 return ExprError(); 6201 } 6202 6203 // We matched a built-in operator; build it. 6204 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6205} 6206 6207Action::OwningExprResult 6208Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 6209 SourceLocation RLoc, 6210 ExprArg Base, ExprArg Idx) { 6211 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 6212 static_cast<Expr*>(Idx.get()) }; 6213 DeclarationName OpName = 6214 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 6215 6216 // If either side is type-dependent, create an appropriate dependent 6217 // expression. 6218 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6219 6220 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6221 UnresolvedLookupExpr *Fn 6222 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6223 0, SourceRange(), OpName, LLoc, 6224 /*ADL*/ true, /*Overloaded*/ false); 6225 // Can't add any actual overloads yet 6226 6227 Base.release(); 6228 Idx.release(); 6229 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 6230 Args, 2, 6231 Context.DependentTy, 6232 RLoc)); 6233 } 6234 6235 // Build an empty overload set. 6236 OverloadCandidateSet CandidateSet(LLoc); 6237 6238 // Subscript can only be overloaded as a member function. 6239 6240 // Add operator candidates that are member functions. 6241 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6242 6243 // Add builtin operator candidates. 6244 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6245 6246 // Perform overload resolution. 6247 OverloadCandidateSet::iterator Best; 6248 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 6249 case OR_Success: { 6250 // We found a built-in operator or an overloaded operator. 6251 FunctionDecl *FnDecl = Best->Function; 6252 6253 if (FnDecl) { 6254 // We matched an overloaded operator. Build a call to that 6255 // operator. 6256 6257 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); 6258 6259 // Convert the arguments. 6260 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 6261 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6262 Best->FoundDecl, Method)) 6263 return ExprError(); 6264 6265 // Convert the arguments. 6266 OwningExprResult InputInit 6267 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6268 FnDecl->getParamDecl(0)), 6269 SourceLocation(), 6270 Owned(Args[1])); 6271 if (InputInit.isInvalid()) 6272 return ExprError(); 6273 6274 Args[1] = InputInit.takeAs<Expr>(); 6275 6276 // Determine the result type 6277 QualType ResultTy 6278 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6279 ResultTy = ResultTy.getNonReferenceType(); 6280 6281 // Build the actual expression node. 6282 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6283 LLoc); 6284 UsualUnaryConversions(FnExpr); 6285 6286 Base.release(); 6287 Idx.release(); 6288 ExprOwningPtr<CXXOperatorCallExpr> 6289 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 6290 FnExpr, Args, 2, 6291 ResultTy, RLoc)); 6292 6293 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 6294 FnDecl)) 6295 return ExprError(); 6296 6297 return MaybeBindToTemporary(TheCall.release()); 6298 } else { 6299 // We matched a built-in operator. Convert the arguments, then 6300 // break out so that we will build the appropriate built-in 6301 // operator node. 6302 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6303 Best->Conversions[0], AA_Passing) || 6304 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6305 Best->Conversions[1], AA_Passing)) 6306 return ExprError(); 6307 6308 break; 6309 } 6310 } 6311 6312 case OR_No_Viable_Function: { 6313 if (CandidateSet.empty()) 6314 Diag(LLoc, diag::err_ovl_no_oper) 6315 << Args[0]->getType() << /*subscript*/ 0 6316 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6317 else 6318 Diag(LLoc, diag::err_ovl_no_viable_subscript) 6319 << Args[0]->getType() 6320 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6321 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6322 "[]", LLoc); 6323 return ExprError(); 6324 } 6325 6326 case OR_Ambiguous: 6327 Diag(LLoc, diag::err_ovl_ambiguous_oper) 6328 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6329 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6330 "[]", LLoc); 6331 return ExprError(); 6332 6333 case OR_Deleted: 6334 Diag(LLoc, diag::err_ovl_deleted_oper) 6335 << Best->Function->isDeleted() << "[]" 6336 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6337 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6338 "[]", LLoc); 6339 return ExprError(); 6340 } 6341 6342 // We matched a built-in operator; build it. 6343 Base.release(); 6344 Idx.release(); 6345 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 6346 Owned(Args[1]), RLoc); 6347} 6348 6349/// BuildCallToMemberFunction - Build a call to a member 6350/// function. MemExpr is the expression that refers to the member 6351/// function (and includes the object parameter), Args/NumArgs are the 6352/// arguments to the function call (not including the object 6353/// parameter). The caller needs to validate that the member 6354/// expression refers to a member function or an overloaded member 6355/// function. 6356Sema::OwningExprResult 6357Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 6358 SourceLocation LParenLoc, Expr **Args, 6359 unsigned NumArgs, SourceLocation *CommaLocs, 6360 SourceLocation RParenLoc) { 6361 // Dig out the member expression. This holds both the object 6362 // argument and the member function we're referring to. 6363 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 6364 6365 MemberExpr *MemExpr; 6366 CXXMethodDecl *Method = 0; 6367 DeclAccessPair FoundDecl = DeclAccessPair::make(0, AS_public); 6368 NestedNameSpecifier *Qualifier = 0; 6369 if (isa<MemberExpr>(NakedMemExpr)) { 6370 MemExpr = cast<MemberExpr>(NakedMemExpr); 6371 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 6372 FoundDecl = MemExpr->getFoundDecl(); 6373 Qualifier = MemExpr->getQualifier(); 6374 } else { 6375 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 6376 Qualifier = UnresExpr->getQualifier(); 6377 6378 QualType ObjectType = UnresExpr->getBaseType(); 6379 6380 // Add overload candidates 6381 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc()); 6382 6383 // FIXME: avoid copy. 6384 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6385 if (UnresExpr->hasExplicitTemplateArgs()) { 6386 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6387 TemplateArgs = &TemplateArgsBuffer; 6388 } 6389 6390 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 6391 E = UnresExpr->decls_end(); I != E; ++I) { 6392 6393 NamedDecl *Func = *I; 6394 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 6395 if (isa<UsingShadowDecl>(Func)) 6396 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 6397 6398 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 6399 // If explicit template arguments were provided, we can't call a 6400 // non-template member function. 6401 if (TemplateArgs) 6402 continue; 6403 6404 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, 6405 Args, NumArgs, 6406 CandidateSet, /*SuppressUserConversions=*/false); 6407 } else { 6408 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 6409 I.getPair(), ActingDC, TemplateArgs, 6410 ObjectType, Args, NumArgs, 6411 CandidateSet, 6412 /*SuppressUsedConversions=*/false); 6413 } 6414 } 6415 6416 DeclarationName DeclName = UnresExpr->getMemberName(); 6417 6418 OverloadCandidateSet::iterator Best; 6419 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 6420 case OR_Success: 6421 Method = cast<CXXMethodDecl>(Best->Function); 6422 FoundDecl = Best->FoundDecl; 6423 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); 6424 break; 6425 6426 case OR_No_Viable_Function: 6427 Diag(UnresExpr->getMemberLoc(), 6428 diag::err_ovl_no_viable_member_function_in_call) 6429 << DeclName << MemExprE->getSourceRange(); 6430 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6431 // FIXME: Leaking incoming expressions! 6432 return ExprError(); 6433 6434 case OR_Ambiguous: 6435 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 6436 << DeclName << MemExprE->getSourceRange(); 6437 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6438 // FIXME: Leaking incoming expressions! 6439 return ExprError(); 6440 6441 case OR_Deleted: 6442 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 6443 << Best->Function->isDeleted() 6444 << DeclName << MemExprE->getSourceRange(); 6445 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6446 // FIXME: Leaking incoming expressions! 6447 return ExprError(); 6448 } 6449 6450 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); 6451 6452 // If overload resolution picked a static member, build a 6453 // non-member call based on that function. 6454 if (Method->isStatic()) { 6455 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 6456 Args, NumArgs, RParenLoc); 6457 } 6458 6459 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 6460 } 6461 6462 assert(Method && "Member call to something that isn't a method?"); 6463 ExprOwningPtr<CXXMemberCallExpr> 6464 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 6465 NumArgs, 6466 Method->getResultType().getNonReferenceType(), 6467 RParenLoc)); 6468 6469 // Check for a valid return type. 6470 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 6471 TheCall.get(), Method)) 6472 return ExprError(); 6473 6474 // Convert the object argument (for a non-static member function call). 6475 // We only need to do this if there was actually an overload; otherwise 6476 // it was done at lookup. 6477 Expr *ObjectArg = MemExpr->getBase(); 6478 if (!Method->isStatic() && 6479 PerformObjectArgumentInitialization(ObjectArg, Qualifier, 6480 FoundDecl, Method)) 6481 return ExprError(); 6482 MemExpr->setBase(ObjectArg); 6483 6484 // Convert the rest of the arguments 6485 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 6486 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 6487 RParenLoc)) 6488 return ExprError(); 6489 6490 if (CheckFunctionCall(Method, TheCall.get())) 6491 return ExprError(); 6492 6493 return MaybeBindToTemporary(TheCall.release()); 6494} 6495 6496/// BuildCallToObjectOfClassType - Build a call to an object of class 6497/// type (C++ [over.call.object]), which can end up invoking an 6498/// overloaded function call operator (@c operator()) or performing a 6499/// user-defined conversion on the object argument. 6500Sema::ExprResult 6501Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 6502 SourceLocation LParenLoc, 6503 Expr **Args, unsigned NumArgs, 6504 SourceLocation *CommaLocs, 6505 SourceLocation RParenLoc) { 6506 assert(Object->getType()->isRecordType() && "Requires object type argument"); 6507 const RecordType *Record = Object->getType()->getAs<RecordType>(); 6508 6509 // C++ [over.call.object]p1: 6510 // If the primary-expression E in the function call syntax 6511 // evaluates to a class object of type "cv T", then the set of 6512 // candidate functions includes at least the function call 6513 // operators of T. The function call operators of T are obtained by 6514 // ordinary lookup of the name operator() in the context of 6515 // (E).operator(). 6516 OverloadCandidateSet CandidateSet(LParenLoc); 6517 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 6518 6519 if (RequireCompleteType(LParenLoc, Object->getType(), 6520 PDiag(diag::err_incomplete_object_call) 6521 << Object->getSourceRange())) 6522 return true; 6523 6524 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 6525 LookupQualifiedName(R, Record->getDecl()); 6526 R.suppressDiagnostics(); 6527 6528 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6529 Oper != OperEnd; ++Oper) { 6530 AddMethodCandidate(Oper.getPair(), Object->getType(), 6531 Args, NumArgs, CandidateSet, 6532 /*SuppressUserConversions=*/ false); 6533 } 6534 6535 // C++ [over.call.object]p2: 6536 // In addition, for each conversion function declared in T of the 6537 // form 6538 // 6539 // operator conversion-type-id () cv-qualifier; 6540 // 6541 // where cv-qualifier is the same cv-qualification as, or a 6542 // greater cv-qualification than, cv, and where conversion-type-id 6543 // denotes the type "pointer to function of (P1,...,Pn) returning 6544 // R", or the type "reference to pointer to function of 6545 // (P1,...,Pn) returning R", or the type "reference to function 6546 // of (P1,...,Pn) returning R", a surrogate call function [...] 6547 // is also considered as a candidate function. Similarly, 6548 // surrogate call functions are added to the set of candidate 6549 // functions for each conversion function declared in an 6550 // accessible base class provided the function is not hidden 6551 // within T by another intervening declaration. 6552 const UnresolvedSetImpl *Conversions 6553 = cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); 6554 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 6555 E = Conversions->end(); I != E; ++I) { 6556 NamedDecl *D = *I; 6557 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 6558 if (isa<UsingShadowDecl>(D)) 6559 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 6560 6561 // Skip over templated conversion functions; they aren't 6562 // surrogates. 6563 if (isa<FunctionTemplateDecl>(D)) 6564 continue; 6565 6566 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 6567 6568 // Strip the reference type (if any) and then the pointer type (if 6569 // any) to get down to what might be a function type. 6570 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 6571 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 6572 ConvType = ConvPtrType->getPointeeType(); 6573 6574 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 6575 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, 6576 Object->getType(), Args, NumArgs, 6577 CandidateSet); 6578 } 6579 6580 // Perform overload resolution. 6581 OverloadCandidateSet::iterator Best; 6582 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 6583 case OR_Success: 6584 // Overload resolution succeeded; we'll build the appropriate call 6585 // below. 6586 break; 6587 6588 case OR_No_Viable_Function: 6589 if (CandidateSet.empty()) 6590 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 6591 << Object->getType() << /*call*/ 1 6592 << Object->getSourceRange(); 6593 else 6594 Diag(Object->getSourceRange().getBegin(), 6595 diag::err_ovl_no_viable_object_call) 6596 << Object->getType() << Object->getSourceRange(); 6597 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6598 break; 6599 6600 case OR_Ambiguous: 6601 Diag(Object->getSourceRange().getBegin(), 6602 diag::err_ovl_ambiguous_object_call) 6603 << Object->getType() << Object->getSourceRange(); 6604 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6605 break; 6606 6607 case OR_Deleted: 6608 Diag(Object->getSourceRange().getBegin(), 6609 diag::err_ovl_deleted_object_call) 6610 << Best->Function->isDeleted() 6611 << Object->getType() << Object->getSourceRange(); 6612 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6613 break; 6614 } 6615 6616 if (Best == CandidateSet.end()) { 6617 // We had an error; delete all of the subexpressions and return 6618 // the error. 6619 Object->Destroy(Context); 6620 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6621 Args[ArgIdx]->Destroy(Context); 6622 return true; 6623 } 6624 6625 if (Best->Function == 0) { 6626 // Since there is no function declaration, this is one of the 6627 // surrogate candidates. Dig out the conversion function. 6628 CXXConversionDecl *Conv 6629 = cast<CXXConversionDecl>( 6630 Best->Conversions[0].UserDefined.ConversionFunction); 6631 6632 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6633 6634 // We selected one of the surrogate functions that converts the 6635 // object parameter to a function pointer. Perform the conversion 6636 // on the object argument, then let ActOnCallExpr finish the job. 6637 6638 // Create an implicit member expr to refer to the conversion operator. 6639 // and then call it. 6640 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Best->FoundDecl, 6641 Conv); 6642 6643 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 6644 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 6645 CommaLocs, RParenLoc).result(); 6646 } 6647 6648 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6649 6650 // We found an overloaded operator(). Build a CXXOperatorCallExpr 6651 // that calls this method, using Object for the implicit object 6652 // parameter and passing along the remaining arguments. 6653 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6654 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6655 6656 unsigned NumArgsInProto = Proto->getNumArgs(); 6657 unsigned NumArgsToCheck = NumArgs; 6658 6659 // Build the full argument list for the method call (the 6660 // implicit object parameter is placed at the beginning of the 6661 // list). 6662 Expr **MethodArgs; 6663 if (NumArgs < NumArgsInProto) { 6664 NumArgsToCheck = NumArgsInProto; 6665 MethodArgs = new Expr*[NumArgsInProto + 1]; 6666 } else { 6667 MethodArgs = new Expr*[NumArgs + 1]; 6668 } 6669 MethodArgs[0] = Object; 6670 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6671 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 6672 6673 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 6674 SourceLocation()); 6675 UsualUnaryConversions(NewFn); 6676 6677 // Once we've built TheCall, all of the expressions are properly 6678 // owned. 6679 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6680 ExprOwningPtr<CXXOperatorCallExpr> 6681 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 6682 MethodArgs, NumArgs + 1, 6683 ResultTy, RParenLoc)); 6684 delete [] MethodArgs; 6685 6686 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 6687 Method)) 6688 return true; 6689 6690 // We may have default arguments. If so, we need to allocate more 6691 // slots in the call for them. 6692 if (NumArgs < NumArgsInProto) 6693 TheCall->setNumArgs(Context, NumArgsInProto + 1); 6694 else if (NumArgs > NumArgsInProto) 6695 NumArgsToCheck = NumArgsInProto; 6696 6697 bool IsError = false; 6698 6699 // Initialize the implicit object parameter. 6700 IsError |= PerformObjectArgumentInitialization(Object, /*Qualifier=*/0, 6701 Best->FoundDecl, Method); 6702 TheCall->setArg(0, Object); 6703 6704 6705 // Check the argument types. 6706 for (unsigned i = 0; i != NumArgsToCheck; i++) { 6707 Expr *Arg; 6708 if (i < NumArgs) { 6709 Arg = Args[i]; 6710 6711 // Pass the argument. 6712 6713 OwningExprResult InputInit 6714 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6715 Method->getParamDecl(i)), 6716 SourceLocation(), Owned(Arg)); 6717 6718 IsError |= InputInit.isInvalid(); 6719 Arg = InputInit.takeAs<Expr>(); 6720 } else { 6721 OwningExprResult DefArg 6722 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 6723 if (DefArg.isInvalid()) { 6724 IsError = true; 6725 break; 6726 } 6727 6728 Arg = DefArg.takeAs<Expr>(); 6729 } 6730 6731 TheCall->setArg(i + 1, Arg); 6732 } 6733 6734 // If this is a variadic call, handle args passed through "...". 6735 if (Proto->isVariadic()) { 6736 // Promote the arguments (C99 6.5.2.2p7). 6737 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 6738 Expr *Arg = Args[i]; 6739 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 6740 TheCall->setArg(i + 1, Arg); 6741 } 6742 } 6743 6744 if (IsError) return true; 6745 6746 if (CheckFunctionCall(Method, TheCall.get())) 6747 return true; 6748 6749 return MaybeBindToTemporary(TheCall.release()).result(); 6750} 6751 6752/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 6753/// (if one exists), where @c Base is an expression of class type and 6754/// @c Member is the name of the member we're trying to find. 6755Sema::OwningExprResult 6756Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 6757 Expr *Base = static_cast<Expr *>(BaseIn.get()); 6758 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 6759 6760 SourceLocation Loc = Base->getExprLoc(); 6761 6762 // C++ [over.ref]p1: 6763 // 6764 // [...] An expression x->m is interpreted as (x.operator->())->m 6765 // for a class object x of type T if T::operator->() exists and if 6766 // the operator is selected as the best match function by the 6767 // overload resolution mechanism (13.3). 6768 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 6769 OverloadCandidateSet CandidateSet(Loc); 6770 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 6771 6772 if (RequireCompleteType(Loc, Base->getType(), 6773 PDiag(diag::err_typecheck_incomplete_tag) 6774 << Base->getSourceRange())) 6775 return ExprError(); 6776 6777 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 6778 LookupQualifiedName(R, BaseRecord->getDecl()); 6779 R.suppressDiagnostics(); 6780 6781 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6782 Oper != OperEnd; ++Oper) { 6783 AddMethodCandidate(Oper.getPair(), Base->getType(), 0, 0, CandidateSet, 6784 /*SuppressUserConversions=*/false); 6785 } 6786 6787 // Perform overload resolution. 6788 OverloadCandidateSet::iterator Best; 6789 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6790 case OR_Success: 6791 // Overload resolution succeeded; we'll build the call below. 6792 break; 6793 6794 case OR_No_Viable_Function: 6795 if (CandidateSet.empty()) 6796 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 6797 << Base->getType() << Base->getSourceRange(); 6798 else 6799 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6800 << "operator->" << Base->getSourceRange(); 6801 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6802 return ExprError(); 6803 6804 case OR_Ambiguous: 6805 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6806 << "->" << Base->getSourceRange(); 6807 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, &Base, 1); 6808 return ExprError(); 6809 6810 case OR_Deleted: 6811 Diag(OpLoc, diag::err_ovl_deleted_oper) 6812 << Best->Function->isDeleted() 6813 << "->" << Base->getSourceRange(); 6814 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6815 return ExprError(); 6816 } 6817 6818 CheckMemberOperatorAccess(OpLoc, Base, 0, Best->FoundDecl); 6819 6820 // Convert the object parameter. 6821 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6822 if (PerformObjectArgumentInitialization(Base, /*Qualifier=*/0, 6823 Best->FoundDecl, Method)) 6824 return ExprError(); 6825 6826 // No concerns about early exits now. 6827 BaseIn.release(); 6828 6829 // Build the operator call. 6830 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 6831 SourceLocation()); 6832 UsualUnaryConversions(FnExpr); 6833 6834 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6835 ExprOwningPtr<CXXOperatorCallExpr> 6836 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 6837 &Base, 1, ResultTy, OpLoc)); 6838 6839 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 6840 Method)) 6841 return ExprError(); 6842 return move(TheCall); 6843} 6844 6845/// FixOverloadedFunctionReference - E is an expression that refers to 6846/// a C++ overloaded function (possibly with some parentheses and 6847/// perhaps a '&' around it). We have resolved the overloaded function 6848/// to the function declaration Fn, so patch up the expression E to 6849/// refer (possibly indirectly) to Fn. Returns the new expr. 6850Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, 6851 FunctionDecl *Fn) { 6852 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 6853 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), 6854 Found, Fn); 6855 if (SubExpr == PE->getSubExpr()) 6856 return PE->Retain(); 6857 6858 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 6859 } 6860 6861 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6862 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), 6863 Found, Fn); 6864 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 6865 SubExpr->getType()) && 6866 "Implicit cast type cannot be determined from overload"); 6867 if (SubExpr == ICE->getSubExpr()) 6868 return ICE->Retain(); 6869 6870 return new (Context) ImplicitCastExpr(ICE->getType(), 6871 ICE->getCastKind(), 6872 SubExpr, 6873 ICE->isLvalueCast()); 6874 } 6875 6876 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 6877 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 6878 "Can only take the address of an overloaded function"); 6879 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 6880 if (Method->isStatic()) { 6881 // Do nothing: static member functions aren't any different 6882 // from non-member functions. 6883 } else { 6884 // Fix the sub expression, which really has to be an 6885 // UnresolvedLookupExpr holding an overloaded member function 6886 // or template. 6887 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6888 Found, Fn); 6889 if (SubExpr == UnOp->getSubExpr()) 6890 return UnOp->Retain(); 6891 6892 assert(isa<DeclRefExpr>(SubExpr) 6893 && "fixed to something other than a decl ref"); 6894 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 6895 && "fixed to a member ref with no nested name qualifier"); 6896 6897 // We have taken the address of a pointer to member 6898 // function. Perform the computation here so that we get the 6899 // appropriate pointer to member type. 6900 QualType ClassType 6901 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 6902 QualType MemPtrType 6903 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 6904 6905 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6906 MemPtrType, UnOp->getOperatorLoc()); 6907 } 6908 } 6909 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6910 Found, Fn); 6911 if (SubExpr == UnOp->getSubExpr()) 6912 return UnOp->Retain(); 6913 6914 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6915 Context.getPointerType(SubExpr->getType()), 6916 UnOp->getOperatorLoc()); 6917 } 6918 6919 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 6920 // FIXME: avoid copy. 6921 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6922 if (ULE->hasExplicitTemplateArgs()) { 6923 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 6924 TemplateArgs = &TemplateArgsBuffer; 6925 } 6926 6927 return DeclRefExpr::Create(Context, 6928 ULE->getQualifier(), 6929 ULE->getQualifierRange(), 6930 Fn, 6931 ULE->getNameLoc(), 6932 Fn->getType(), 6933 TemplateArgs); 6934 } 6935 6936 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 6937 // FIXME: avoid copy. 6938 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6939 if (MemExpr->hasExplicitTemplateArgs()) { 6940 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6941 TemplateArgs = &TemplateArgsBuffer; 6942 } 6943 6944 Expr *Base; 6945 6946 // If we're filling in 6947 if (MemExpr->isImplicitAccess()) { 6948 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 6949 return DeclRefExpr::Create(Context, 6950 MemExpr->getQualifier(), 6951 MemExpr->getQualifierRange(), 6952 Fn, 6953 MemExpr->getMemberLoc(), 6954 Fn->getType(), 6955 TemplateArgs); 6956 } else { 6957 SourceLocation Loc = MemExpr->getMemberLoc(); 6958 if (MemExpr->getQualifier()) 6959 Loc = MemExpr->getQualifierRange().getBegin(); 6960 Base = new (Context) CXXThisExpr(Loc, 6961 MemExpr->getBaseType(), 6962 /*isImplicit=*/true); 6963 } 6964 } else 6965 Base = MemExpr->getBase()->Retain(); 6966 6967 return MemberExpr::Create(Context, Base, 6968 MemExpr->isArrow(), 6969 MemExpr->getQualifier(), 6970 MemExpr->getQualifierRange(), 6971 Fn, 6972 Found, 6973 MemExpr->getMemberLoc(), 6974 TemplateArgs, 6975 Fn->getType()); 6976 } 6977 6978 assert(false && "Invalid reference to overloaded function"); 6979 return E->Retain(); 6980} 6981 6982Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 6983 DeclAccessPair Found, 6984 FunctionDecl *Fn) { 6985 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Found, Fn)); 6986} 6987 6988} // end namespace clang 6989