SemaOverload.cpp revision c6dfe194f623b02c123759f235b504d4850fc178
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 278namespace { 279 // Structure used by OverloadCandidate::DeductionFailureInfo to store 280 // template parameter and template argument information. 281 struct DFIParamWithArguments { 282 TemplateParameter Param; 283 TemplateArgument FirstArg; 284 TemplateArgument SecondArg; 285 }; 286} 287 288/// \brief Convert from Sema's representation of template deduction information 289/// to the form used in overload-candidate information. 290OverloadCandidate::DeductionFailureInfo 291static MakeDeductionFailureInfo(ASTContext &Context, 292 Sema::TemplateDeductionResult TDK, 293 Sema::TemplateDeductionInfo &Info) { 294 OverloadCandidate::DeductionFailureInfo Result; 295 Result.Result = static_cast<unsigned>(TDK); 296 Result.Data = 0; 297 switch (TDK) { 298 case Sema::TDK_Success: 299 case Sema::TDK_InstantiationDepth: 300 case Sema::TDK_TooManyArguments: 301 case Sema::TDK_TooFewArguments: 302 break; 303 304 case Sema::TDK_Incomplete: 305 case Sema::TDK_InvalidExplicitArguments: 306 Result.Data = Info.Param.getOpaqueValue(); 307 break; 308 309 case Sema::TDK_Inconsistent: 310 case Sema::TDK_InconsistentQuals: { 311 // FIXME: Should allocate from normal heap so that we can free this later. 312 DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments; 313 Saved->Param = Info.Param; 314 Saved->FirstArg = Info.FirstArg; 315 Saved->SecondArg = Info.SecondArg; 316 Result.Data = Saved; 317 break; 318 } 319 320 case Sema::TDK_SubstitutionFailure: 321 Result.Data = Info.take(); 322 break; 323 324 case Sema::TDK_NonDeducedMismatch: 325 case Sema::TDK_FailedOverloadResolution: 326 break; 327 } 328 329 return Result; 330} 331 332void OverloadCandidate::DeductionFailureInfo::Destroy() { 333 switch (static_cast<Sema::TemplateDeductionResult>(Result)) { 334 case Sema::TDK_Success: 335 case Sema::TDK_InstantiationDepth: 336 case Sema::TDK_Incomplete: 337 case Sema::TDK_TooManyArguments: 338 case Sema::TDK_TooFewArguments: 339 case Sema::TDK_InvalidExplicitArguments: 340 break; 341 342 case Sema::TDK_Inconsistent: 343 case Sema::TDK_InconsistentQuals: 344 // FIXME: Destroy the data? 345 Data = 0; 346 break; 347 348 case Sema::TDK_SubstitutionFailure: 349 // FIXME: Destroy the template arugment list? 350 Data = 0; 351 break; 352 353 // Unhandled 354 case Sema::TDK_NonDeducedMismatch: 355 case Sema::TDK_FailedOverloadResolution: 356 break; 357 } 358} 359 360TemplateParameter 361OverloadCandidate::DeductionFailureInfo::getTemplateParameter() { 362 switch (static_cast<Sema::TemplateDeductionResult>(Result)) { 363 case Sema::TDK_Success: 364 case Sema::TDK_InstantiationDepth: 365 case Sema::TDK_TooManyArguments: 366 case Sema::TDK_TooFewArguments: 367 case Sema::TDK_SubstitutionFailure: 368 return TemplateParameter(); 369 370 case Sema::TDK_Incomplete: 371 case Sema::TDK_InvalidExplicitArguments: 372 return TemplateParameter::getFromOpaqueValue(Data); 373 374 case Sema::TDK_Inconsistent: 375 case Sema::TDK_InconsistentQuals: 376 return static_cast<DFIParamWithArguments*>(Data)->Param; 377 378 // Unhandled 379 case Sema::TDK_NonDeducedMismatch: 380 case Sema::TDK_FailedOverloadResolution: 381 break; 382 } 383 384 return TemplateParameter(); 385} 386 387TemplateArgumentList * 388OverloadCandidate::DeductionFailureInfo::getTemplateArgumentList() { 389 switch (static_cast<Sema::TemplateDeductionResult>(Result)) { 390 case Sema::TDK_Success: 391 case Sema::TDK_InstantiationDepth: 392 case Sema::TDK_TooManyArguments: 393 case Sema::TDK_TooFewArguments: 394 case Sema::TDK_Incomplete: 395 case Sema::TDK_InvalidExplicitArguments: 396 case Sema::TDK_Inconsistent: 397 case Sema::TDK_InconsistentQuals: 398 return 0; 399 400 case Sema::TDK_SubstitutionFailure: 401 return static_cast<TemplateArgumentList*>(Data); 402 403 // Unhandled 404 case Sema::TDK_NonDeducedMismatch: 405 case Sema::TDK_FailedOverloadResolution: 406 break; 407 } 408 409 return 0; 410} 411 412const TemplateArgument *OverloadCandidate::DeductionFailureInfo::getFirstArg() { 413 switch (static_cast<Sema::TemplateDeductionResult>(Result)) { 414 case Sema::TDK_Success: 415 case Sema::TDK_InstantiationDepth: 416 case Sema::TDK_Incomplete: 417 case Sema::TDK_TooManyArguments: 418 case Sema::TDK_TooFewArguments: 419 case Sema::TDK_InvalidExplicitArguments: 420 case Sema::TDK_SubstitutionFailure: 421 return 0; 422 423 case Sema::TDK_Inconsistent: 424 case Sema::TDK_InconsistentQuals: 425 return &static_cast<DFIParamWithArguments*>(Data)->FirstArg; 426 427 // Unhandled 428 case Sema::TDK_NonDeducedMismatch: 429 case Sema::TDK_FailedOverloadResolution: 430 break; 431 } 432 433 return 0; 434} 435 436const TemplateArgument * 437OverloadCandidate::DeductionFailureInfo::getSecondArg() { 438 switch (static_cast<Sema::TemplateDeductionResult>(Result)) { 439 case Sema::TDK_Success: 440 case Sema::TDK_InstantiationDepth: 441 case Sema::TDK_Incomplete: 442 case Sema::TDK_TooManyArguments: 443 case Sema::TDK_TooFewArguments: 444 case Sema::TDK_InvalidExplicitArguments: 445 case Sema::TDK_SubstitutionFailure: 446 return 0; 447 448 case Sema::TDK_Inconsistent: 449 case Sema::TDK_InconsistentQuals: 450 return &static_cast<DFIParamWithArguments*>(Data)->SecondArg; 451 452 // Unhandled 453 case Sema::TDK_NonDeducedMismatch: 454 case Sema::TDK_FailedOverloadResolution: 455 break; 456 } 457 458 return 0; 459} 460 461void OverloadCandidateSet::clear() { 462 inherited::clear(); 463 Functions.clear(); 464} 465 466// IsOverload - Determine whether the given New declaration is an 467// overload of the declarations in Old. This routine returns false if 468// New and Old cannot be overloaded, e.g., if New has the same 469// signature as some function in Old (C++ 1.3.10) or if the Old 470// declarations aren't functions (or function templates) at all. When 471// it does return false, MatchedDecl will point to the decl that New 472// cannot be overloaded with. This decl may be a UsingShadowDecl on 473// top of the underlying declaration. 474// 475// Example: Given the following input: 476// 477// void f(int, float); // #1 478// void f(int, int); // #2 479// int f(int, int); // #3 480// 481// When we process #1, there is no previous declaration of "f", 482// so IsOverload will not be used. 483// 484// When we process #2, Old contains only the FunctionDecl for #1. By 485// comparing the parameter types, we see that #1 and #2 are overloaded 486// (since they have different signatures), so this routine returns 487// false; MatchedDecl is unchanged. 488// 489// When we process #3, Old is an overload set containing #1 and #2. We 490// compare the signatures of #3 to #1 (they're overloaded, so we do 491// nothing) and then #3 to #2. Since the signatures of #3 and #2 are 492// identical (return types of functions are not part of the 493// signature), IsOverload returns false and MatchedDecl will be set to 494// point to the FunctionDecl for #2. 495Sema::OverloadKind 496Sema::CheckOverload(FunctionDecl *New, const LookupResult &Old, 497 NamedDecl *&Match) { 498 for (LookupResult::iterator I = Old.begin(), E = Old.end(); 499 I != E; ++I) { 500 NamedDecl *OldD = (*I)->getUnderlyingDecl(); 501 if (FunctionTemplateDecl *OldT = dyn_cast<FunctionTemplateDecl>(OldD)) { 502 if (!IsOverload(New, OldT->getTemplatedDecl())) { 503 Match = *I; 504 return Ovl_Match; 505 } 506 } else if (FunctionDecl *OldF = dyn_cast<FunctionDecl>(OldD)) { 507 if (!IsOverload(New, OldF)) { 508 Match = *I; 509 return Ovl_Match; 510 } 511 } else if (isa<UsingDecl>(OldD) || isa<TagDecl>(OldD)) { 512 // We can overload with these, which can show up when doing 513 // redeclaration checks for UsingDecls. 514 assert(Old.getLookupKind() == LookupUsingDeclName); 515 } else if (isa<UnresolvedUsingValueDecl>(OldD)) { 516 // Optimistically assume that an unresolved using decl will 517 // overload; if it doesn't, we'll have to diagnose during 518 // template instantiation. 519 } else { 520 // (C++ 13p1): 521 // Only function declarations can be overloaded; object and type 522 // declarations cannot be overloaded. 523 Match = *I; 524 return Ovl_NonFunction; 525 } 526 } 527 528 return Ovl_Overload; 529} 530 531bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old) { 532 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate(); 533 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate(); 534 535 // C++ [temp.fct]p2: 536 // A function template can be overloaded with other function templates 537 // and with normal (non-template) functions. 538 if ((OldTemplate == 0) != (NewTemplate == 0)) 539 return true; 540 541 // Is the function New an overload of the function Old? 542 QualType OldQType = Context.getCanonicalType(Old->getType()); 543 QualType NewQType = Context.getCanonicalType(New->getType()); 544 545 // Compare the signatures (C++ 1.3.10) of the two functions to 546 // determine whether they are overloads. If we find any mismatch 547 // in the signature, they are overloads. 548 549 // If either of these functions is a K&R-style function (no 550 // prototype), then we consider them to have matching signatures. 551 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 552 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 553 return false; 554 555 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType); 556 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType); 557 558 // The signature of a function includes the types of its 559 // parameters (C++ 1.3.10), which includes the presence or absence 560 // of the ellipsis; see C++ DR 357). 561 if (OldQType != NewQType && 562 (OldType->getNumArgs() != NewType->getNumArgs() || 563 OldType->isVariadic() != NewType->isVariadic() || 564 !FunctionArgTypesAreEqual(OldType, NewType))) 565 return true; 566 567 // C++ [temp.over.link]p4: 568 // The signature of a function template consists of its function 569 // signature, its return type and its template parameter list. The names 570 // of the template parameters are significant only for establishing the 571 // relationship between the template parameters and the rest of the 572 // signature. 573 // 574 // We check the return type and template parameter lists for function 575 // templates first; the remaining checks follow. 576 if (NewTemplate && 577 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), 578 OldTemplate->getTemplateParameters(), 579 false, TPL_TemplateMatch) || 580 OldType->getResultType() != NewType->getResultType())) 581 return true; 582 583 // If the function is a class member, its signature includes the 584 // cv-qualifiers (if any) on the function itself. 585 // 586 // As part of this, also check whether one of the member functions 587 // is static, in which case they are not overloads (C++ 588 // 13.1p2). While not part of the definition of the signature, 589 // this check is important to determine whether these functions 590 // can be overloaded. 591 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 592 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 593 if (OldMethod && NewMethod && 594 !OldMethod->isStatic() && !NewMethod->isStatic() && 595 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 596 return true; 597 598 // The signatures match; this is not an overload. 599 return false; 600} 601 602/// TryImplicitConversion - Attempt to perform an implicit conversion 603/// from the given expression (Expr) to the given type (ToType). This 604/// function returns an implicit conversion sequence that can be used 605/// to perform the initialization. Given 606/// 607/// void f(float f); 608/// void g(int i) { f(i); } 609/// 610/// this routine would produce an implicit conversion sequence to 611/// describe the initialization of f from i, which will be a standard 612/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 613/// 4.1) followed by a floating-integral conversion (C++ 4.9). 614// 615/// Note that this routine only determines how the conversion can be 616/// performed; it does not actually perform the conversion. As such, 617/// it will not produce any diagnostics if no conversion is available, 618/// but will instead return an implicit conversion sequence of kind 619/// "BadConversion". 620/// 621/// If @p SuppressUserConversions, then user-defined conversions are 622/// not permitted. 623/// If @p AllowExplicit, then explicit user-defined conversions are 624/// permitted. 625ImplicitConversionSequence 626Sema::TryImplicitConversion(Expr* From, QualType ToType, 627 bool SuppressUserConversions, 628 bool AllowExplicit, 629 bool InOverloadResolution) { 630 ImplicitConversionSequence ICS; 631 if (IsStandardConversion(From, ToType, InOverloadResolution, ICS.Standard)) { 632 ICS.setStandard(); 633 return ICS; 634 } 635 636 if (!getLangOptions().CPlusPlus) { 637 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 638 return ICS; 639 } 640 641 if (SuppressUserConversions) { 642 // C++ [over.ics.user]p4: 643 // A conversion of an expression of class type to the same class 644 // type is given Exact Match rank, and a conversion of an 645 // expression of class type to a base class of that type is 646 // given Conversion rank, in spite of the fact that a copy/move 647 // constructor (i.e., a user-defined conversion function) is 648 // called for those cases. 649 QualType FromType = From->getType(); 650 if (!ToType->getAs<RecordType>() || !FromType->getAs<RecordType>() || 651 !(Context.hasSameUnqualifiedType(FromType, ToType) || 652 IsDerivedFrom(FromType, ToType))) { 653 // We're not in the case above, so there is no conversion that 654 // we can perform. 655 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 656 return ICS; 657 } 658 659 ICS.setStandard(); 660 ICS.Standard.setAsIdentityConversion(); 661 ICS.Standard.setFromType(FromType); 662 ICS.Standard.setAllToTypes(ToType); 663 664 // We don't actually check at this point whether there is a valid 665 // copy/move constructor, since overloading just assumes that it 666 // exists. When we actually perform initialization, we'll find the 667 // appropriate constructor to copy the returned object, if needed. 668 ICS.Standard.CopyConstructor = 0; 669 670 // Determine whether this is considered a derived-to-base conversion. 671 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 672 ICS.Standard.Second = ICK_Derived_To_Base; 673 674 return ICS; 675 } 676 677 // Attempt user-defined conversion. 678 OverloadCandidateSet Conversions(From->getExprLoc()); 679 OverloadingResult UserDefResult 680 = IsUserDefinedConversion(From, ToType, ICS.UserDefined, Conversions, 681 AllowExplicit); 682 683 if (UserDefResult == OR_Success) { 684 ICS.setUserDefined(); 685 // C++ [over.ics.user]p4: 686 // A conversion of an expression of class type to the same class 687 // type is given Exact Match rank, and a conversion of an 688 // expression of class type to a base class of that type is 689 // given Conversion rank, in spite of the fact that a copy 690 // constructor (i.e., a user-defined conversion function) is 691 // called for those cases. 692 if (CXXConstructorDecl *Constructor 693 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 694 QualType FromCanon 695 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 696 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 697 if (Constructor->isCopyConstructor() && 698 (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) { 699 // Turn this into a "standard" conversion sequence, so that it 700 // gets ranked with standard conversion sequences. 701 ICS.setStandard(); 702 ICS.Standard.setAsIdentityConversion(); 703 ICS.Standard.setFromType(From->getType()); 704 ICS.Standard.setAllToTypes(ToType); 705 ICS.Standard.CopyConstructor = Constructor; 706 if (ToCanon != FromCanon) 707 ICS.Standard.Second = ICK_Derived_To_Base; 708 } 709 } 710 711 // C++ [over.best.ics]p4: 712 // However, when considering the argument of a user-defined 713 // conversion function that is a candidate by 13.3.1.3 when 714 // invoked for the copying of the temporary in the second step 715 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 716 // 13.3.1.6 in all cases, only standard conversion sequences and 717 // ellipsis conversion sequences are allowed. 718 if (SuppressUserConversions && ICS.isUserDefined()) { 719 ICS.setBad(BadConversionSequence::suppressed_user, From, ToType); 720 } 721 } else if (UserDefResult == OR_Ambiguous && !SuppressUserConversions) { 722 ICS.setAmbiguous(); 723 ICS.Ambiguous.setFromType(From->getType()); 724 ICS.Ambiguous.setToType(ToType); 725 for (OverloadCandidateSet::iterator Cand = Conversions.begin(); 726 Cand != Conversions.end(); ++Cand) 727 if (Cand->Viable) 728 ICS.Ambiguous.addConversion(Cand->Function); 729 } else { 730 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 731 } 732 733 return ICS; 734} 735 736/// PerformImplicitConversion - Perform an implicit conversion of the 737/// expression From to the type ToType. Returns true if there was an 738/// error, false otherwise. The expression From is replaced with the 739/// converted expression. Flavor is the kind of conversion we're 740/// performing, used in the error message. If @p AllowExplicit, 741/// explicit user-defined conversions are permitted. 742bool 743Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 744 AssignmentAction Action, bool AllowExplicit) { 745 ImplicitConversionSequence ICS; 746 return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS); 747} 748 749bool 750Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 751 AssignmentAction Action, bool AllowExplicit, 752 ImplicitConversionSequence& ICS) { 753 ICS = TryImplicitConversion(From, ToType, 754 /*SuppressUserConversions=*/false, 755 AllowExplicit, 756 /*InOverloadResolution=*/false); 757 return PerformImplicitConversion(From, ToType, ICS, Action); 758} 759 760/// \brief Determine whether the conversion from FromType to ToType is a valid 761/// conversion that strips "noreturn" off the nested function type. 762static bool IsNoReturnConversion(ASTContext &Context, QualType FromType, 763 QualType ToType, QualType &ResultTy) { 764 if (Context.hasSameUnqualifiedType(FromType, ToType)) 765 return false; 766 767 // Strip the noreturn off the type we're converting from; noreturn can 768 // safely be removed. 769 FromType = Context.getNoReturnType(FromType, false); 770 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 771 return false; 772 773 ResultTy = FromType; 774 return true; 775} 776 777/// IsStandardConversion - Determines whether there is a standard 778/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 779/// expression From to the type ToType. Standard conversion sequences 780/// only consider non-class types; for conversions that involve class 781/// types, use TryImplicitConversion. If a conversion exists, SCS will 782/// contain the standard conversion sequence required to perform this 783/// conversion and this routine will return true. Otherwise, this 784/// routine will return false and the value of SCS is unspecified. 785bool 786Sema::IsStandardConversion(Expr* From, QualType ToType, 787 bool InOverloadResolution, 788 StandardConversionSequence &SCS) { 789 QualType FromType = From->getType(); 790 791 // Standard conversions (C++ [conv]) 792 SCS.setAsIdentityConversion(); 793 SCS.DeprecatedStringLiteralToCharPtr = false; 794 SCS.IncompatibleObjC = false; 795 SCS.setFromType(FromType); 796 SCS.CopyConstructor = 0; 797 798 // There are no standard conversions for class types in C++, so 799 // abort early. When overloading in C, however, we do permit 800 if (FromType->isRecordType() || ToType->isRecordType()) { 801 if (getLangOptions().CPlusPlus) 802 return false; 803 804 // When we're overloading in C, we allow, as standard conversions, 805 } 806 807 // The first conversion can be an lvalue-to-rvalue conversion, 808 // array-to-pointer conversion, or function-to-pointer conversion 809 // (C++ 4p1). 810 811 if (FromType == Context.OverloadTy) { 812 DeclAccessPair AccessPair; 813 if (FunctionDecl *Fn 814 = ResolveAddressOfOverloadedFunction(From, ToType, false, 815 AccessPair)) { 816 // We were able to resolve the address of the overloaded function, 817 // so we can convert to the type of that function. 818 FromType = Fn->getType(); 819 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 820 if (!Method->isStatic()) { 821 Type *ClassType 822 = Context.getTypeDeclType(Method->getParent()).getTypePtr(); 823 FromType = Context.getMemberPointerType(FromType, ClassType); 824 } 825 } 826 827 // If the "from" expression takes the address of the overloaded 828 // function, update the type of the resulting expression accordingly. 829 if (FromType->getAs<FunctionType>()) 830 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(From->IgnoreParens())) 831 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 832 FromType = Context.getPointerType(FromType); 833 834 // Check that we've computed the proper type after overload resolution. 835 assert(Context.hasSameType(FromType, 836 FixOverloadedFunctionReference(From, AccessPair, Fn)->getType())); 837 } else { 838 return false; 839 } 840 } 841 // Lvalue-to-rvalue conversion (C++ 4.1): 842 // An lvalue (3.10) of a non-function, non-array type T can be 843 // converted to an rvalue. 844 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 845 if (argIsLvalue == Expr::LV_Valid && 846 !FromType->isFunctionType() && !FromType->isArrayType() && 847 Context.getCanonicalType(FromType) != Context.OverloadTy) { 848 SCS.First = ICK_Lvalue_To_Rvalue; 849 850 // If T is a non-class type, the type of the rvalue is the 851 // cv-unqualified version of T. Otherwise, the type of the rvalue 852 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 853 // just strip the qualifiers because they don't matter. 854 FromType = FromType.getUnqualifiedType(); 855 } else if (FromType->isArrayType()) { 856 // Array-to-pointer conversion (C++ 4.2) 857 SCS.First = ICK_Array_To_Pointer; 858 859 // An lvalue or rvalue of type "array of N T" or "array of unknown 860 // bound of T" can be converted to an rvalue of type "pointer to 861 // T" (C++ 4.2p1). 862 FromType = Context.getArrayDecayedType(FromType); 863 864 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 865 // This conversion is deprecated. (C++ D.4). 866 SCS.DeprecatedStringLiteralToCharPtr = true; 867 868 // For the purpose of ranking in overload resolution 869 // (13.3.3.1.1), this conversion is considered an 870 // array-to-pointer conversion followed by a qualification 871 // conversion (4.4). (C++ 4.2p2) 872 SCS.Second = ICK_Identity; 873 SCS.Third = ICK_Qualification; 874 SCS.setAllToTypes(FromType); 875 return true; 876 } 877 } else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 878 // Function-to-pointer conversion (C++ 4.3). 879 SCS.First = ICK_Function_To_Pointer; 880 881 // An lvalue of function type T can be converted to an rvalue of 882 // type "pointer to T." The result is a pointer to the 883 // function. (C++ 4.3p1). 884 FromType = Context.getPointerType(FromType); 885 } else { 886 // We don't require any conversions for the first step. 887 SCS.First = ICK_Identity; 888 } 889 SCS.setToType(0, FromType); 890 891 // The second conversion can be an integral promotion, floating 892 // point promotion, integral conversion, floating point conversion, 893 // floating-integral conversion, pointer conversion, 894 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 895 // For overloading in C, this can also be a "compatible-type" 896 // conversion. 897 bool IncompatibleObjC = false; 898 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 899 // The unqualified versions of the types are the same: there's no 900 // conversion to do. 901 SCS.Second = ICK_Identity; 902 } else if (IsIntegralPromotion(From, FromType, ToType)) { 903 // Integral promotion (C++ 4.5). 904 SCS.Second = ICK_Integral_Promotion; 905 FromType = ToType.getUnqualifiedType(); 906 } else if (IsFloatingPointPromotion(FromType, ToType)) { 907 // Floating point promotion (C++ 4.6). 908 SCS.Second = ICK_Floating_Promotion; 909 FromType = ToType.getUnqualifiedType(); 910 } else if (IsComplexPromotion(FromType, ToType)) { 911 // Complex promotion (Clang extension) 912 SCS.Second = ICK_Complex_Promotion; 913 FromType = ToType.getUnqualifiedType(); 914 } else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 915 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 916 // Integral conversions (C++ 4.7). 917 SCS.Second = ICK_Integral_Conversion; 918 FromType = ToType.getUnqualifiedType(); 919 } else if (FromType->isComplexType() && ToType->isComplexType()) { 920 // Complex conversions (C99 6.3.1.6) 921 SCS.Second = ICK_Complex_Conversion; 922 FromType = ToType.getUnqualifiedType(); 923 } else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 924 (ToType->isComplexType() && FromType->isArithmeticType())) { 925 // Complex-real conversions (C99 6.3.1.7) 926 SCS.Second = ICK_Complex_Real; 927 FromType = ToType.getUnqualifiedType(); 928 } else if (FromType->isFloatingType() && ToType->isFloatingType()) { 929 // Floating point conversions (C++ 4.8). 930 SCS.Second = ICK_Floating_Conversion; 931 FromType = ToType.getUnqualifiedType(); 932 } else if ((FromType->isFloatingType() && 933 ToType->isIntegralType() && (!ToType->isBooleanType() && 934 !ToType->isEnumeralType())) || 935 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 936 ToType->isFloatingType())) { 937 // Floating-integral conversions (C++ 4.9). 938 SCS.Second = ICK_Floating_Integral; 939 FromType = ToType.getUnqualifiedType(); 940 } else if (IsPointerConversion(From, FromType, ToType, InOverloadResolution, 941 FromType, IncompatibleObjC)) { 942 // Pointer conversions (C++ 4.10). 943 SCS.Second = ICK_Pointer_Conversion; 944 SCS.IncompatibleObjC = IncompatibleObjC; 945 } else if (IsMemberPointerConversion(From, FromType, ToType, 946 InOverloadResolution, FromType)) { 947 // Pointer to member conversions (4.11). 948 SCS.Second = ICK_Pointer_Member; 949 } else if (ToType->isBooleanType() && 950 (FromType->isArithmeticType() || 951 FromType->isEnumeralType() || 952 FromType->isAnyPointerType() || 953 FromType->isBlockPointerType() || 954 FromType->isMemberPointerType() || 955 FromType->isNullPtrType())) { 956 // Boolean conversions (C++ 4.12). 957 SCS.Second = ICK_Boolean_Conversion; 958 FromType = Context.BoolTy; 959 } else if (!getLangOptions().CPlusPlus && 960 Context.typesAreCompatible(ToType, FromType)) { 961 // Compatible conversions (Clang extension for C function overloading) 962 SCS.Second = ICK_Compatible_Conversion; 963 } else if (IsNoReturnConversion(Context, FromType, ToType, FromType)) { 964 // Treat a conversion that strips "noreturn" as an identity conversion. 965 SCS.Second = ICK_NoReturn_Adjustment; 966 } else { 967 // No second conversion required. 968 SCS.Second = ICK_Identity; 969 } 970 SCS.setToType(1, FromType); 971 972 QualType CanonFrom; 973 QualType CanonTo; 974 // The third conversion can be a qualification conversion (C++ 4p1). 975 if (IsQualificationConversion(FromType, ToType)) { 976 SCS.Third = ICK_Qualification; 977 FromType = ToType; 978 CanonFrom = Context.getCanonicalType(FromType); 979 CanonTo = Context.getCanonicalType(ToType); 980 } else { 981 // No conversion required 982 SCS.Third = ICK_Identity; 983 984 // C++ [over.best.ics]p6: 985 // [...] Any difference in top-level cv-qualification is 986 // subsumed by the initialization itself and does not constitute 987 // a conversion. [...] 988 CanonFrom = Context.getCanonicalType(FromType); 989 CanonTo = Context.getCanonicalType(ToType); 990 if (CanonFrom.getLocalUnqualifiedType() 991 == CanonTo.getLocalUnqualifiedType() && 992 CanonFrom.getLocalCVRQualifiers() != CanonTo.getLocalCVRQualifiers()) { 993 FromType = ToType; 994 CanonFrom = CanonTo; 995 } 996 } 997 SCS.setToType(2, FromType); 998 999 // If we have not converted the argument type to the parameter type, 1000 // this is a bad conversion sequence. 1001 if (CanonFrom != CanonTo) 1002 return false; 1003 1004 return true; 1005} 1006 1007/// IsIntegralPromotion - Determines whether the conversion from the 1008/// expression From (whose potentially-adjusted type is FromType) to 1009/// ToType is an integral promotion (C++ 4.5). If so, returns true and 1010/// sets PromotedType to the promoted type. 1011bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { 1012 const BuiltinType *To = ToType->getAs<BuiltinType>(); 1013 // All integers are built-in. 1014 if (!To) { 1015 return false; 1016 } 1017 1018 // An rvalue of type char, signed char, unsigned char, short int, or 1019 // unsigned short int can be converted to an rvalue of type int if 1020 // int can represent all the values of the source type; otherwise, 1021 // the source rvalue can be converted to an rvalue of type unsigned 1022 // int (C++ 4.5p1). 1023 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && 1024 !FromType->isEnumeralType()) { 1025 if (// We can promote any signed, promotable integer type to an int 1026 (FromType->isSignedIntegerType() || 1027 // We can promote any unsigned integer type whose size is 1028 // less than int to an int. 1029 (!FromType->isSignedIntegerType() && 1030 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 1031 return To->getKind() == BuiltinType::Int; 1032 } 1033 1034 return To->getKind() == BuiltinType::UInt; 1035 } 1036 1037 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 1038 // can be converted to an rvalue of the first of the following types 1039 // that can represent all the values of its underlying type: int, 1040 // unsigned int, long, or unsigned long (C++ 4.5p2). 1041 1042 // We pre-calculate the promotion type for enum types. 1043 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) 1044 if (ToType->isIntegerType()) 1045 return Context.hasSameUnqualifiedType(ToType, 1046 FromEnumType->getDecl()->getPromotionType()); 1047 1048 if (FromType->isWideCharType() && ToType->isIntegerType()) { 1049 // Determine whether the type we're converting from is signed or 1050 // unsigned. 1051 bool FromIsSigned; 1052 uint64_t FromSize = Context.getTypeSize(FromType); 1053 1054 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 1055 FromIsSigned = true; 1056 1057 // The types we'll try to promote to, in the appropriate 1058 // order. Try each of these types. 1059 QualType PromoteTypes[6] = { 1060 Context.IntTy, Context.UnsignedIntTy, 1061 Context.LongTy, Context.UnsignedLongTy , 1062 Context.LongLongTy, Context.UnsignedLongLongTy 1063 }; 1064 for (int Idx = 0; Idx < 6; ++Idx) { 1065 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 1066 if (FromSize < ToSize || 1067 (FromSize == ToSize && 1068 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 1069 // We found the type that we can promote to. If this is the 1070 // type we wanted, we have a promotion. Otherwise, no 1071 // promotion. 1072 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); 1073 } 1074 } 1075 } 1076 1077 // An rvalue for an integral bit-field (9.6) can be converted to an 1078 // rvalue of type int if int can represent all the values of the 1079 // bit-field; otherwise, it can be converted to unsigned int if 1080 // unsigned int can represent all the values of the bit-field. If 1081 // the bit-field is larger yet, no integral promotion applies to 1082 // it. If the bit-field has an enumerated type, it is treated as any 1083 // other value of that type for promotion purposes (C++ 4.5p3). 1084 // FIXME: We should delay checking of bit-fields until we actually perform the 1085 // conversion. 1086 using llvm::APSInt; 1087 if (From) 1088 if (FieldDecl *MemberDecl = From->getBitField()) { 1089 APSInt BitWidth; 1090 if (FromType->isIntegralType() && !FromType->isEnumeralType() && 1091 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { 1092 APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned()); 1093 ToSize = Context.getTypeSize(ToType); 1094 1095 // Are we promoting to an int from a bitfield that fits in an int? 1096 if (BitWidth < ToSize || 1097 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 1098 return To->getKind() == BuiltinType::Int; 1099 } 1100 1101 // Are we promoting to an unsigned int from an unsigned bitfield 1102 // that fits into an unsigned int? 1103 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 1104 return To->getKind() == BuiltinType::UInt; 1105 } 1106 1107 return false; 1108 } 1109 } 1110 1111 // An rvalue of type bool can be converted to an rvalue of type int, 1112 // with false becoming zero and true becoming one (C++ 4.5p4). 1113 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 1114 return true; 1115 } 1116 1117 return false; 1118} 1119 1120/// IsFloatingPointPromotion - Determines whether the conversion from 1121/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 1122/// returns true and sets PromotedType to the promoted type. 1123bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { 1124 /// An rvalue of type float can be converted to an rvalue of type 1125 /// double. (C++ 4.6p1). 1126 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) 1127 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { 1128 if (FromBuiltin->getKind() == BuiltinType::Float && 1129 ToBuiltin->getKind() == BuiltinType::Double) 1130 return true; 1131 1132 // C99 6.3.1.5p1: 1133 // When a float is promoted to double or long double, or a 1134 // double is promoted to long double [...]. 1135 if (!getLangOptions().CPlusPlus && 1136 (FromBuiltin->getKind() == BuiltinType::Float || 1137 FromBuiltin->getKind() == BuiltinType::Double) && 1138 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 1139 return true; 1140 } 1141 1142 return false; 1143} 1144 1145/// \brief Determine if a conversion is a complex promotion. 1146/// 1147/// A complex promotion is defined as a complex -> complex conversion 1148/// where the conversion between the underlying real types is a 1149/// floating-point or integral promotion. 1150bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 1151 const ComplexType *FromComplex = FromType->getAs<ComplexType>(); 1152 if (!FromComplex) 1153 return false; 1154 1155 const ComplexType *ToComplex = ToType->getAs<ComplexType>(); 1156 if (!ToComplex) 1157 return false; 1158 1159 return IsFloatingPointPromotion(FromComplex->getElementType(), 1160 ToComplex->getElementType()) || 1161 IsIntegralPromotion(0, FromComplex->getElementType(), 1162 ToComplex->getElementType()); 1163} 1164 1165/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 1166/// the pointer type FromPtr to a pointer to type ToPointee, with the 1167/// same type qualifiers as FromPtr has on its pointee type. ToType, 1168/// if non-empty, will be a pointer to ToType that may or may not have 1169/// the right set of qualifiers on its pointee. 1170static QualType 1171BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 1172 QualType ToPointee, QualType ToType, 1173 ASTContext &Context) { 1174 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 1175 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 1176 Qualifiers Quals = CanonFromPointee.getQualifiers(); 1177 1178 // Exact qualifier match -> return the pointer type we're converting to. 1179 if (CanonToPointee.getLocalQualifiers() == Quals) { 1180 // ToType is exactly what we need. Return it. 1181 if (!ToType.isNull()) 1182 return ToType; 1183 1184 // Build a pointer to ToPointee. It has the right qualifiers 1185 // already. 1186 return Context.getPointerType(ToPointee); 1187 } 1188 1189 // Just build a canonical type that has the right qualifiers. 1190 return Context.getPointerType( 1191 Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), 1192 Quals)); 1193} 1194 1195/// BuildSimilarlyQualifiedObjCObjectPointerType - In a pointer conversion from 1196/// the FromType, which is an objective-c pointer, to ToType, which may or may 1197/// not have the right set of qualifiers. 1198static QualType 1199BuildSimilarlyQualifiedObjCObjectPointerType(QualType FromType, 1200 QualType ToType, 1201 ASTContext &Context) { 1202 QualType CanonFromType = Context.getCanonicalType(FromType); 1203 QualType CanonToType = Context.getCanonicalType(ToType); 1204 Qualifiers Quals = CanonFromType.getQualifiers(); 1205 1206 // Exact qualifier match -> return the pointer type we're converting to. 1207 if (CanonToType.getLocalQualifiers() == Quals) 1208 return ToType; 1209 1210 // Just build a canonical type that has the right qualifiers. 1211 return Context.getQualifiedType(CanonToType.getLocalUnqualifiedType(), Quals); 1212} 1213 1214static bool isNullPointerConstantForConversion(Expr *Expr, 1215 bool InOverloadResolution, 1216 ASTContext &Context) { 1217 // Handle value-dependent integral null pointer constants correctly. 1218 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 1219 if (Expr->isValueDependent() && !Expr->isTypeDependent() && 1220 Expr->getType()->isIntegralType()) 1221 return !InOverloadResolution; 1222 1223 return Expr->isNullPointerConstant(Context, 1224 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1225 : Expr::NPC_ValueDependentIsNull); 1226} 1227 1228/// IsPointerConversion - Determines whether the conversion of the 1229/// expression From, which has the (possibly adjusted) type FromType, 1230/// can be converted to the type ToType via a pointer conversion (C++ 1231/// 4.10). If so, returns true and places the converted type (that 1232/// might differ from ToType in its cv-qualifiers at some level) into 1233/// ConvertedType. 1234/// 1235/// This routine also supports conversions to and from block pointers 1236/// and conversions with Objective-C's 'id', 'id<protocols...>', and 1237/// pointers to interfaces. FIXME: Once we've determined the 1238/// appropriate overloading rules for Objective-C, we may want to 1239/// split the Objective-C checks into a different routine; however, 1240/// GCC seems to consider all of these conversions to be pointer 1241/// conversions, so for now they live here. IncompatibleObjC will be 1242/// set if the conversion is an allowed Objective-C conversion that 1243/// should result in a warning. 1244bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 1245 bool InOverloadResolution, 1246 QualType& ConvertedType, 1247 bool &IncompatibleObjC) { 1248 IncompatibleObjC = false; 1249 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 1250 return true; 1251 1252 // Conversion from a null pointer constant to any Objective-C pointer type. 1253 if (ToType->isObjCObjectPointerType() && 1254 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1255 ConvertedType = ToType; 1256 return true; 1257 } 1258 1259 // Blocks: Block pointers can be converted to void*. 1260 if (FromType->isBlockPointerType() && ToType->isPointerType() && 1261 ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) { 1262 ConvertedType = ToType; 1263 return true; 1264 } 1265 // Blocks: A null pointer constant can be converted to a block 1266 // pointer type. 1267 if (ToType->isBlockPointerType() && 1268 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1269 ConvertedType = ToType; 1270 return true; 1271 } 1272 1273 // If the left-hand-side is nullptr_t, the right side can be a null 1274 // pointer constant. 1275 if (ToType->isNullPtrType() && 1276 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1277 ConvertedType = ToType; 1278 return true; 1279 } 1280 1281 const PointerType* ToTypePtr = ToType->getAs<PointerType>(); 1282 if (!ToTypePtr) 1283 return false; 1284 1285 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 1286 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1287 ConvertedType = ToType; 1288 return true; 1289 } 1290 1291 // Beyond this point, both types need to be pointers 1292 // , including objective-c pointers. 1293 QualType ToPointeeType = ToTypePtr->getPointeeType(); 1294 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType()) { 1295 ConvertedType = BuildSimilarlyQualifiedObjCObjectPointerType(FromType, 1296 ToType, Context); 1297 return true; 1298 1299 } 1300 const PointerType *FromTypePtr = FromType->getAs<PointerType>(); 1301 if (!FromTypePtr) 1302 return false; 1303 1304 QualType FromPointeeType = FromTypePtr->getPointeeType(); 1305 1306 // An rvalue of type "pointer to cv T," where T is an object type, 1307 // can be converted to an rvalue of type "pointer to cv void" (C++ 1308 // 4.10p2). 1309 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 1310 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1311 ToPointeeType, 1312 ToType, Context); 1313 return true; 1314 } 1315 1316 // When we're overloading in C, we allow a special kind of pointer 1317 // conversion for compatible-but-not-identical pointee types. 1318 if (!getLangOptions().CPlusPlus && 1319 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 1320 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1321 ToPointeeType, 1322 ToType, Context); 1323 return true; 1324 } 1325 1326 // C++ [conv.ptr]p3: 1327 // 1328 // An rvalue of type "pointer to cv D," where D is a class type, 1329 // can be converted to an rvalue of type "pointer to cv B," where 1330 // B is a base class (clause 10) of D. If B is an inaccessible 1331 // (clause 11) or ambiguous (10.2) base class of D, a program that 1332 // necessitates this conversion is ill-formed. The result of the 1333 // conversion is a pointer to the base class sub-object of the 1334 // derived class object. The null pointer value is converted to 1335 // the null pointer value of the destination type. 1336 // 1337 // Note that we do not check for ambiguity or inaccessibility 1338 // here. That is handled by CheckPointerConversion. 1339 if (getLangOptions().CPlusPlus && 1340 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1341 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && 1342 !RequireCompleteType(From->getLocStart(), FromPointeeType, PDiag()) && 1343 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 1344 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1345 ToPointeeType, 1346 ToType, Context); 1347 return true; 1348 } 1349 1350 return false; 1351} 1352 1353/// isObjCPointerConversion - Determines whether this is an 1354/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 1355/// with the same arguments and return values. 1356bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 1357 QualType& ConvertedType, 1358 bool &IncompatibleObjC) { 1359 if (!getLangOptions().ObjC1) 1360 return false; 1361 1362 // First, we handle all conversions on ObjC object pointer types. 1363 const ObjCObjectPointerType* ToObjCPtr = ToType->getAs<ObjCObjectPointerType>(); 1364 const ObjCObjectPointerType *FromObjCPtr = 1365 FromType->getAs<ObjCObjectPointerType>(); 1366 1367 if (ToObjCPtr && FromObjCPtr) { 1368 // Objective C++: We're able to convert between "id" or "Class" and a 1369 // pointer to any interface (in both directions). 1370 if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) { 1371 ConvertedType = ToType; 1372 return true; 1373 } 1374 // Conversions with Objective-C's id<...>. 1375 if ((FromObjCPtr->isObjCQualifiedIdType() || 1376 ToObjCPtr->isObjCQualifiedIdType()) && 1377 Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType, 1378 /*compare=*/false)) { 1379 ConvertedType = ToType; 1380 return true; 1381 } 1382 // Objective C++: We're able to convert from a pointer to an 1383 // interface to a pointer to a different interface. 1384 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { 1385 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); 1386 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); 1387 if (getLangOptions().CPlusPlus && LHS && RHS && 1388 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( 1389 FromObjCPtr->getPointeeType())) 1390 return false; 1391 ConvertedType = ToType; 1392 return true; 1393 } 1394 1395 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { 1396 // Okay: this is some kind of implicit downcast of Objective-C 1397 // interfaces, which is permitted. However, we're going to 1398 // complain about it. 1399 IncompatibleObjC = true; 1400 ConvertedType = FromType; 1401 return true; 1402 } 1403 } 1404 // Beyond this point, both types need to be C pointers or block pointers. 1405 QualType ToPointeeType; 1406 if (const PointerType *ToCPtr = ToType->getAs<PointerType>()) 1407 ToPointeeType = ToCPtr->getPointeeType(); 1408 else if (const BlockPointerType *ToBlockPtr = 1409 ToType->getAs<BlockPointerType>()) { 1410 // Objective C++: We're able to convert from a pointer to any object 1411 // to a block pointer type. 1412 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { 1413 ConvertedType = ToType; 1414 return true; 1415 } 1416 ToPointeeType = ToBlockPtr->getPointeeType(); 1417 } 1418 else if (FromType->getAs<BlockPointerType>() && 1419 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { 1420 // Objective C++: We're able to convert from a block pointer type to a 1421 // pointer to any object. 1422 ConvertedType = ToType; 1423 return true; 1424 } 1425 else 1426 return false; 1427 1428 QualType FromPointeeType; 1429 if (const PointerType *FromCPtr = FromType->getAs<PointerType>()) 1430 FromPointeeType = FromCPtr->getPointeeType(); 1431 else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>()) 1432 FromPointeeType = FromBlockPtr->getPointeeType(); 1433 else 1434 return false; 1435 1436 // If we have pointers to pointers, recursively check whether this 1437 // is an Objective-C conversion. 1438 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1439 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1440 IncompatibleObjC)) { 1441 // We always complain about this conversion. 1442 IncompatibleObjC = true; 1443 ConvertedType = ToType; 1444 return true; 1445 } 1446 // Allow conversion of pointee being objective-c pointer to another one; 1447 // as in I* to id. 1448 if (FromPointeeType->getAs<ObjCObjectPointerType>() && 1449 ToPointeeType->getAs<ObjCObjectPointerType>() && 1450 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1451 IncompatibleObjC)) { 1452 ConvertedType = ToType; 1453 return true; 1454 } 1455 1456 // If we have pointers to functions or blocks, check whether the only 1457 // differences in the argument and result types are in Objective-C 1458 // pointer conversions. If so, we permit the conversion (but 1459 // complain about it). 1460 const FunctionProtoType *FromFunctionType 1461 = FromPointeeType->getAs<FunctionProtoType>(); 1462 const FunctionProtoType *ToFunctionType 1463 = ToPointeeType->getAs<FunctionProtoType>(); 1464 if (FromFunctionType && ToFunctionType) { 1465 // If the function types are exactly the same, this isn't an 1466 // Objective-C pointer conversion. 1467 if (Context.getCanonicalType(FromPointeeType) 1468 == Context.getCanonicalType(ToPointeeType)) 1469 return false; 1470 1471 // Perform the quick checks that will tell us whether these 1472 // function types are obviously different. 1473 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1474 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1475 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1476 return false; 1477 1478 bool HasObjCConversion = false; 1479 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1480 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1481 // Okay, the types match exactly. Nothing to do. 1482 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1483 ToFunctionType->getResultType(), 1484 ConvertedType, IncompatibleObjC)) { 1485 // Okay, we have an Objective-C pointer conversion. 1486 HasObjCConversion = true; 1487 } else { 1488 // Function types are too different. Abort. 1489 return false; 1490 } 1491 1492 // Check argument types. 1493 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1494 ArgIdx != NumArgs; ++ArgIdx) { 1495 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1496 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1497 if (Context.getCanonicalType(FromArgType) 1498 == Context.getCanonicalType(ToArgType)) { 1499 // Okay, the types match exactly. Nothing to do. 1500 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1501 ConvertedType, IncompatibleObjC)) { 1502 // Okay, we have an Objective-C pointer conversion. 1503 HasObjCConversion = true; 1504 } else { 1505 // Argument types are too different. Abort. 1506 return false; 1507 } 1508 } 1509 1510 if (HasObjCConversion) { 1511 // We had an Objective-C conversion. Allow this pointer 1512 // conversion, but complain about it. 1513 ConvertedType = ToType; 1514 IncompatibleObjC = true; 1515 return true; 1516 } 1517 } 1518 1519 return false; 1520} 1521 1522/// FunctionArgTypesAreEqual - This routine checks two function proto types 1523/// for equlity of their argument types. Caller has already checked that 1524/// they have same number of arguments. This routine assumes that Objective-C 1525/// pointer types which only differ in their protocol qualifiers are equal. 1526bool Sema::FunctionArgTypesAreEqual(FunctionProtoType* OldType, 1527 FunctionProtoType* NewType){ 1528 if (!getLangOptions().ObjC1) 1529 return std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 1530 NewType->arg_type_begin()); 1531 1532 for (FunctionProtoType::arg_type_iterator O = OldType->arg_type_begin(), 1533 N = NewType->arg_type_begin(), 1534 E = OldType->arg_type_end(); O && (O != E); ++O, ++N) { 1535 QualType ToType = (*O); 1536 QualType FromType = (*N); 1537 if (ToType != FromType) { 1538 if (const PointerType *PTTo = ToType->getAs<PointerType>()) { 1539 if (const PointerType *PTFr = FromType->getAs<PointerType>()) 1540 if ((PTTo->getPointeeType()->isObjCQualifiedIdType() && 1541 PTFr->getPointeeType()->isObjCQualifiedIdType()) || 1542 (PTTo->getPointeeType()->isObjCQualifiedClassType() && 1543 PTFr->getPointeeType()->isObjCQualifiedClassType())) 1544 continue; 1545 } 1546 else if (ToType->isObjCObjectPointerType() && 1547 FromType->isObjCObjectPointerType()) { 1548 QualType ToInterfaceTy = ToType->getPointeeType(); 1549 QualType FromInterfaceTy = FromType->getPointeeType(); 1550 if (const ObjCInterfaceType *OITTo = 1551 ToInterfaceTy->getAs<ObjCInterfaceType>()) 1552 if (const ObjCInterfaceType *OITFr = 1553 FromInterfaceTy->getAs<ObjCInterfaceType>()) 1554 if (OITTo->getDecl() == OITFr->getDecl()) 1555 continue; 1556 } 1557 return false; 1558 } 1559 } 1560 return true; 1561} 1562 1563/// CheckPointerConversion - Check the pointer conversion from the 1564/// expression From to the type ToType. This routine checks for 1565/// ambiguous or inaccessible derived-to-base pointer 1566/// conversions for which IsPointerConversion has already returned 1567/// true. It returns true and produces a diagnostic if there was an 1568/// error, or returns false otherwise. 1569bool Sema::CheckPointerConversion(Expr *From, QualType ToType, 1570 CastExpr::CastKind &Kind, 1571 CXXBaseSpecifierArray& BasePath, 1572 bool IgnoreBaseAccess) { 1573 QualType FromType = From->getType(); 1574 1575 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) 1576 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { 1577 QualType FromPointeeType = FromPtrType->getPointeeType(), 1578 ToPointeeType = ToPtrType->getPointeeType(); 1579 1580 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1581 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { 1582 // We must have a derived-to-base conversion. Check an 1583 // ambiguous or inaccessible conversion. 1584 if (CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1585 From->getExprLoc(), 1586 From->getSourceRange(), &BasePath, 1587 IgnoreBaseAccess)) 1588 return true; 1589 1590 // The conversion was successful. 1591 Kind = CastExpr::CK_DerivedToBase; 1592 } 1593 } 1594 if (const ObjCObjectPointerType *FromPtrType = 1595 FromType->getAs<ObjCObjectPointerType>()) 1596 if (const ObjCObjectPointerType *ToPtrType = 1597 ToType->getAs<ObjCObjectPointerType>()) { 1598 // Objective-C++ conversions are always okay. 1599 // FIXME: We should have a different class of conversions for the 1600 // Objective-C++ implicit conversions. 1601 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) 1602 return false; 1603 1604 } 1605 return false; 1606} 1607 1608/// IsMemberPointerConversion - Determines whether the conversion of the 1609/// expression From, which has the (possibly adjusted) type FromType, can be 1610/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1611/// If so, returns true and places the converted type (that might differ from 1612/// ToType in its cv-qualifiers at some level) into ConvertedType. 1613bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1614 QualType ToType, 1615 bool InOverloadResolution, 1616 QualType &ConvertedType) { 1617 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>(); 1618 if (!ToTypePtr) 1619 return false; 1620 1621 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1622 if (From->isNullPointerConstant(Context, 1623 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1624 : Expr::NPC_ValueDependentIsNull)) { 1625 ConvertedType = ToType; 1626 return true; 1627 } 1628 1629 // Otherwise, both types have to be member pointers. 1630 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>(); 1631 if (!FromTypePtr) 1632 return false; 1633 1634 // A pointer to member of B can be converted to a pointer to member of D, 1635 // where D is derived from B (C++ 4.11p2). 1636 QualType FromClass(FromTypePtr->getClass(), 0); 1637 QualType ToClass(ToTypePtr->getClass(), 0); 1638 // FIXME: What happens when these are dependent? Is this function even called? 1639 1640 if (IsDerivedFrom(ToClass, FromClass)) { 1641 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1642 ToClass.getTypePtr()); 1643 return true; 1644 } 1645 1646 return false; 1647} 1648 1649/// CheckMemberPointerConversion - Check the member pointer conversion from the 1650/// expression From to the type ToType. This routine checks for ambiguous or 1651/// virtual or inaccessible base-to-derived member pointer conversions 1652/// for which IsMemberPointerConversion has already returned true. It returns 1653/// true and produces a diagnostic if there was an error, or returns false 1654/// otherwise. 1655bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, 1656 CastExpr::CastKind &Kind, 1657 CXXBaseSpecifierArray &BasePath, 1658 bool IgnoreBaseAccess) { 1659 QualType FromType = From->getType(); 1660 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); 1661 if (!FromPtrType) { 1662 // This must be a null pointer to member pointer conversion 1663 assert(From->isNullPointerConstant(Context, 1664 Expr::NPC_ValueDependentIsNull) && 1665 "Expr must be null pointer constant!"); 1666 Kind = CastExpr::CK_NullToMemberPointer; 1667 return false; 1668 } 1669 1670 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>(); 1671 assert(ToPtrType && "No member pointer cast has a target type " 1672 "that is not a member pointer."); 1673 1674 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1675 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1676 1677 // FIXME: What about dependent types? 1678 assert(FromClass->isRecordType() && "Pointer into non-class."); 1679 assert(ToClass->isRecordType() && "Pointer into non-class."); 1680 1681 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true, 1682 /*DetectVirtual=*/true); 1683 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1684 assert(DerivationOkay && 1685 "Should not have been called if derivation isn't OK."); 1686 (void)DerivationOkay; 1687 1688 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1689 getUnqualifiedType())) { 1690 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1691 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1692 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1693 return true; 1694 } 1695 1696 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1697 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1698 << FromClass << ToClass << QualType(VBase, 0) 1699 << From->getSourceRange(); 1700 return true; 1701 } 1702 1703 if (!IgnoreBaseAccess) 1704 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, 1705 Paths.front(), 1706 diag::err_downcast_from_inaccessible_base); 1707 1708 // Must be a base to derived member conversion. 1709 BuildBasePathArray(Paths, BasePath); 1710 Kind = CastExpr::CK_BaseToDerivedMemberPointer; 1711 return false; 1712} 1713 1714/// IsQualificationConversion - Determines whether the conversion from 1715/// an rvalue of type FromType to ToType is a qualification conversion 1716/// (C++ 4.4). 1717bool 1718Sema::IsQualificationConversion(QualType FromType, QualType ToType) { 1719 FromType = Context.getCanonicalType(FromType); 1720 ToType = Context.getCanonicalType(ToType); 1721 1722 // If FromType and ToType are the same type, this is not a 1723 // qualification conversion. 1724 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) 1725 return false; 1726 1727 // (C++ 4.4p4): 1728 // A conversion can add cv-qualifiers at levels other than the first 1729 // in multi-level pointers, subject to the following rules: [...] 1730 bool PreviousToQualsIncludeConst = true; 1731 bool UnwrappedAnyPointer = false; 1732 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1733 // Within each iteration of the loop, we check the qualifiers to 1734 // determine if this still looks like a qualification 1735 // conversion. Then, if all is well, we unwrap one more level of 1736 // pointers or pointers-to-members and do it all again 1737 // until there are no more pointers or pointers-to-members left to 1738 // unwrap. 1739 UnwrappedAnyPointer = true; 1740 1741 // -- for every j > 0, if const is in cv 1,j then const is in cv 1742 // 2,j, and similarly for volatile. 1743 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1744 return false; 1745 1746 // -- if the cv 1,j and cv 2,j are different, then const is in 1747 // every cv for 0 < k < j. 1748 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1749 && !PreviousToQualsIncludeConst) 1750 return false; 1751 1752 // Keep track of whether all prior cv-qualifiers in the "to" type 1753 // include const. 1754 PreviousToQualsIncludeConst 1755 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1756 } 1757 1758 // We are left with FromType and ToType being the pointee types 1759 // after unwrapping the original FromType and ToType the same number 1760 // of types. If we unwrapped any pointers, and if FromType and 1761 // ToType have the same unqualified type (since we checked 1762 // qualifiers above), then this is a qualification conversion. 1763 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); 1764} 1765 1766/// Determines whether there is a user-defined conversion sequence 1767/// (C++ [over.ics.user]) that converts expression From to the type 1768/// ToType. If such a conversion exists, User will contain the 1769/// user-defined conversion sequence that performs such a conversion 1770/// and this routine will return true. Otherwise, this routine returns 1771/// false and User is unspecified. 1772/// 1773/// \param AllowExplicit true if the conversion should consider C++0x 1774/// "explicit" conversion functions as well as non-explicit conversion 1775/// functions (C++0x [class.conv.fct]p2). 1776OverloadingResult Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1777 UserDefinedConversionSequence& User, 1778 OverloadCandidateSet& CandidateSet, 1779 bool AllowExplicit) { 1780 // Whether we will only visit constructors. 1781 bool ConstructorsOnly = false; 1782 1783 // If the type we are conversion to is a class type, enumerate its 1784 // constructors. 1785 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { 1786 // C++ [over.match.ctor]p1: 1787 // When objects of class type are direct-initialized (8.5), or 1788 // copy-initialized from an expression of the same or a 1789 // derived class type (8.5), overload resolution selects the 1790 // constructor. [...] For copy-initialization, the candidate 1791 // functions are all the converting constructors (12.3.1) of 1792 // that class. The argument list is the expression-list within 1793 // the parentheses of the initializer. 1794 if (Context.hasSameUnqualifiedType(ToType, From->getType()) || 1795 (From->getType()->getAs<RecordType>() && 1796 IsDerivedFrom(From->getType(), ToType))) 1797 ConstructorsOnly = true; 1798 1799 if (RequireCompleteType(From->getLocStart(), ToType, PDiag())) { 1800 // We're not going to find any constructors. 1801 } else if (CXXRecordDecl *ToRecordDecl 1802 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1803 DeclarationName ConstructorName 1804 = Context.DeclarationNames.getCXXConstructorName( 1805 Context.getCanonicalType(ToType).getUnqualifiedType()); 1806 DeclContext::lookup_iterator Con, ConEnd; 1807 for (llvm::tie(Con, ConEnd) 1808 = ToRecordDecl->lookup(ConstructorName); 1809 Con != ConEnd; ++Con) { 1810 NamedDecl *D = *Con; 1811 DeclAccessPair FoundDecl = DeclAccessPair::make(D, D->getAccess()); 1812 1813 // Find the constructor (which may be a template). 1814 CXXConstructorDecl *Constructor = 0; 1815 FunctionTemplateDecl *ConstructorTmpl 1816 = dyn_cast<FunctionTemplateDecl>(D); 1817 if (ConstructorTmpl) 1818 Constructor 1819 = cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl()); 1820 else 1821 Constructor = cast<CXXConstructorDecl>(D); 1822 1823 if (!Constructor->isInvalidDecl() && 1824 Constructor->isConvertingConstructor(AllowExplicit)) { 1825 if (ConstructorTmpl) 1826 AddTemplateOverloadCandidate(ConstructorTmpl, FoundDecl, 1827 /*ExplicitArgs*/ 0, 1828 &From, 1, CandidateSet, 1829 /*SuppressUserConversions=*/!ConstructorsOnly); 1830 else 1831 // Allow one user-defined conversion when user specifies a 1832 // From->ToType conversion via an static cast (c-style, etc). 1833 AddOverloadCandidate(Constructor, FoundDecl, 1834 &From, 1, CandidateSet, 1835 /*SuppressUserConversions=*/!ConstructorsOnly); 1836 } 1837 } 1838 } 1839 } 1840 1841 // Enumerate conversion functions, if we're allowed to. 1842 if (ConstructorsOnly) { 1843 } else if (RequireCompleteType(From->getLocStart(), From->getType(), 1844 PDiag(0) << From->getSourceRange())) { 1845 // No conversion functions from incomplete types. 1846 } else if (const RecordType *FromRecordType 1847 = From->getType()->getAs<RecordType>()) { 1848 if (CXXRecordDecl *FromRecordDecl 1849 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1850 // Add all of the conversion functions as candidates. 1851 const UnresolvedSetImpl *Conversions 1852 = FromRecordDecl->getVisibleConversionFunctions(); 1853 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 1854 E = Conversions->end(); I != E; ++I) { 1855 DeclAccessPair FoundDecl = I.getPair(); 1856 NamedDecl *D = FoundDecl.getDecl(); 1857 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 1858 if (isa<UsingShadowDecl>(D)) 1859 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 1860 1861 CXXConversionDecl *Conv; 1862 FunctionTemplateDecl *ConvTemplate; 1863 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) 1864 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 1865 else 1866 Conv = cast<CXXConversionDecl>(D); 1867 1868 if (AllowExplicit || !Conv->isExplicit()) { 1869 if (ConvTemplate) 1870 AddTemplateConversionCandidate(ConvTemplate, FoundDecl, 1871 ActingContext, From, ToType, 1872 CandidateSet); 1873 else 1874 AddConversionCandidate(Conv, FoundDecl, ActingContext, 1875 From, ToType, CandidateSet); 1876 } 1877 } 1878 } 1879 } 1880 1881 OverloadCandidateSet::iterator Best; 1882 switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) { 1883 case OR_Success: 1884 // Record the standard conversion we used and the conversion function. 1885 if (CXXConstructorDecl *Constructor 1886 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1887 // C++ [over.ics.user]p1: 1888 // If the user-defined conversion is specified by a 1889 // constructor (12.3.1), the initial standard conversion 1890 // sequence converts the source type to the type required by 1891 // the argument of the constructor. 1892 // 1893 QualType ThisType = Constructor->getThisType(Context); 1894 if (Best->Conversions[0].isEllipsis()) 1895 User.EllipsisConversion = true; 1896 else { 1897 User.Before = Best->Conversions[0].Standard; 1898 User.EllipsisConversion = false; 1899 } 1900 User.ConversionFunction = Constructor; 1901 User.After.setAsIdentityConversion(); 1902 User.After.setFromType( 1903 ThisType->getAs<PointerType>()->getPointeeType()); 1904 User.After.setAllToTypes(ToType); 1905 return OR_Success; 1906 } else if (CXXConversionDecl *Conversion 1907 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1908 // C++ [over.ics.user]p1: 1909 // 1910 // [...] If the user-defined conversion is specified by a 1911 // conversion function (12.3.2), the initial standard 1912 // conversion sequence converts the source type to the 1913 // implicit object parameter of the conversion function. 1914 User.Before = Best->Conversions[0].Standard; 1915 User.ConversionFunction = Conversion; 1916 User.EllipsisConversion = false; 1917 1918 // C++ [over.ics.user]p2: 1919 // The second standard conversion sequence converts the 1920 // result of the user-defined conversion to the target type 1921 // for the sequence. Since an implicit conversion sequence 1922 // is an initialization, the special rules for 1923 // initialization by user-defined conversion apply when 1924 // selecting the best user-defined conversion for a 1925 // user-defined conversion sequence (see 13.3.3 and 1926 // 13.3.3.1). 1927 User.After = Best->FinalConversion; 1928 return OR_Success; 1929 } else { 1930 assert(false && "Not a constructor or conversion function?"); 1931 return OR_No_Viable_Function; 1932 } 1933 1934 case OR_No_Viable_Function: 1935 return OR_No_Viable_Function; 1936 case OR_Deleted: 1937 // No conversion here! We're done. 1938 return OR_Deleted; 1939 1940 case OR_Ambiguous: 1941 return OR_Ambiguous; 1942 } 1943 1944 return OR_No_Viable_Function; 1945} 1946 1947bool 1948Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { 1949 ImplicitConversionSequence ICS; 1950 OverloadCandidateSet CandidateSet(From->getExprLoc()); 1951 OverloadingResult OvResult = 1952 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 1953 CandidateSet, false); 1954 if (OvResult == OR_Ambiguous) 1955 Diag(From->getSourceRange().getBegin(), 1956 diag::err_typecheck_ambiguous_condition) 1957 << From->getType() << ToType << From->getSourceRange(); 1958 else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) 1959 Diag(From->getSourceRange().getBegin(), 1960 diag::err_typecheck_nonviable_condition) 1961 << From->getType() << ToType << From->getSourceRange(); 1962 else 1963 return false; 1964 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &From, 1); 1965 return true; 1966} 1967 1968/// CompareImplicitConversionSequences - Compare two implicit 1969/// conversion sequences to determine whether one is better than the 1970/// other or if they are indistinguishable (C++ 13.3.3.2). 1971ImplicitConversionSequence::CompareKind 1972Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1973 const ImplicitConversionSequence& ICS2) 1974{ 1975 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1976 // conversion sequences (as defined in 13.3.3.1) 1977 // -- a standard conversion sequence (13.3.3.1.1) is a better 1978 // conversion sequence than a user-defined conversion sequence or 1979 // an ellipsis conversion sequence, and 1980 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1981 // conversion sequence than an ellipsis conversion sequence 1982 // (13.3.3.1.3). 1983 // 1984 // C++0x [over.best.ics]p10: 1985 // For the purpose of ranking implicit conversion sequences as 1986 // described in 13.3.3.2, the ambiguous conversion sequence is 1987 // treated as a user-defined sequence that is indistinguishable 1988 // from any other user-defined conversion sequence. 1989 if (ICS1.getKindRank() < ICS2.getKindRank()) 1990 return ImplicitConversionSequence::Better; 1991 else if (ICS2.getKindRank() < ICS1.getKindRank()) 1992 return ImplicitConversionSequence::Worse; 1993 1994 // The following checks require both conversion sequences to be of 1995 // the same kind. 1996 if (ICS1.getKind() != ICS2.getKind()) 1997 return ImplicitConversionSequence::Indistinguishable; 1998 1999 // Two implicit conversion sequences of the same form are 2000 // indistinguishable conversion sequences unless one of the 2001 // following rules apply: (C++ 13.3.3.2p3): 2002 if (ICS1.isStandard()) 2003 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 2004 else if (ICS1.isUserDefined()) { 2005 // User-defined conversion sequence U1 is a better conversion 2006 // sequence than another user-defined conversion sequence U2 if 2007 // they contain the same user-defined conversion function or 2008 // constructor and if the second standard conversion sequence of 2009 // U1 is better than the second standard conversion sequence of 2010 // U2 (C++ 13.3.3.2p3). 2011 if (ICS1.UserDefined.ConversionFunction == 2012 ICS2.UserDefined.ConversionFunction) 2013 return CompareStandardConversionSequences(ICS1.UserDefined.After, 2014 ICS2.UserDefined.After); 2015 } 2016 2017 return ImplicitConversionSequence::Indistinguishable; 2018} 2019 2020// Per 13.3.3.2p3, compare the given standard conversion sequences to 2021// determine if one is a proper subset of the other. 2022static ImplicitConversionSequence::CompareKind 2023compareStandardConversionSubsets(ASTContext &Context, 2024 const StandardConversionSequence& SCS1, 2025 const StandardConversionSequence& SCS2) { 2026 ImplicitConversionSequence::CompareKind Result 2027 = ImplicitConversionSequence::Indistinguishable; 2028 2029 if (SCS1.Second != SCS2.Second) { 2030 if (SCS1.Second == ICK_Identity) 2031 Result = ImplicitConversionSequence::Better; 2032 else if (SCS2.Second == ICK_Identity) 2033 Result = ImplicitConversionSequence::Worse; 2034 else 2035 return ImplicitConversionSequence::Indistinguishable; 2036 } else if (!Context.hasSameType(SCS1.getToType(1), SCS2.getToType(1))) 2037 return ImplicitConversionSequence::Indistinguishable; 2038 2039 if (SCS1.Third == SCS2.Third) { 2040 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result 2041 : ImplicitConversionSequence::Indistinguishable; 2042 } 2043 2044 if (SCS1.Third == ICK_Identity) 2045 return Result == ImplicitConversionSequence::Worse 2046 ? ImplicitConversionSequence::Indistinguishable 2047 : ImplicitConversionSequence::Better; 2048 2049 if (SCS2.Third == ICK_Identity) 2050 return Result == ImplicitConversionSequence::Better 2051 ? ImplicitConversionSequence::Indistinguishable 2052 : ImplicitConversionSequence::Worse; 2053 2054 return ImplicitConversionSequence::Indistinguishable; 2055} 2056 2057/// CompareStandardConversionSequences - Compare two standard 2058/// conversion sequences to determine whether one is better than the 2059/// other or if they are indistinguishable (C++ 13.3.3.2p3). 2060ImplicitConversionSequence::CompareKind 2061Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 2062 const StandardConversionSequence& SCS2) 2063{ 2064 // Standard conversion sequence S1 is a better conversion sequence 2065 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 2066 2067 // -- S1 is a proper subsequence of S2 (comparing the conversion 2068 // sequences in the canonical form defined by 13.3.3.1.1, 2069 // excluding any Lvalue Transformation; the identity conversion 2070 // sequence is considered to be a subsequence of any 2071 // non-identity conversion sequence) or, if not that, 2072 if (ImplicitConversionSequence::CompareKind CK 2073 = compareStandardConversionSubsets(Context, SCS1, SCS2)) 2074 return CK; 2075 2076 // -- the rank of S1 is better than the rank of S2 (by the rules 2077 // defined below), or, if not that, 2078 ImplicitConversionRank Rank1 = SCS1.getRank(); 2079 ImplicitConversionRank Rank2 = SCS2.getRank(); 2080 if (Rank1 < Rank2) 2081 return ImplicitConversionSequence::Better; 2082 else if (Rank2 < Rank1) 2083 return ImplicitConversionSequence::Worse; 2084 2085 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 2086 // are indistinguishable unless one of the following rules 2087 // applies: 2088 2089 // A conversion that is not a conversion of a pointer, or 2090 // pointer to member, to bool is better than another conversion 2091 // that is such a conversion. 2092 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 2093 return SCS2.isPointerConversionToBool() 2094 ? ImplicitConversionSequence::Better 2095 : ImplicitConversionSequence::Worse; 2096 2097 // C++ [over.ics.rank]p4b2: 2098 // 2099 // If class B is derived directly or indirectly from class A, 2100 // conversion of B* to A* is better than conversion of B* to 2101 // void*, and conversion of A* to void* is better than conversion 2102 // of B* to void*. 2103 bool SCS1ConvertsToVoid 2104 = SCS1.isPointerConversionToVoidPointer(Context); 2105 bool SCS2ConvertsToVoid 2106 = SCS2.isPointerConversionToVoidPointer(Context); 2107 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 2108 // Exactly one of the conversion sequences is a conversion to 2109 // a void pointer; it's the worse conversion. 2110 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 2111 : ImplicitConversionSequence::Worse; 2112 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 2113 // Neither conversion sequence converts to a void pointer; compare 2114 // their derived-to-base conversions. 2115 if (ImplicitConversionSequence::CompareKind DerivedCK 2116 = CompareDerivedToBaseConversions(SCS1, SCS2)) 2117 return DerivedCK; 2118 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 2119 // Both conversion sequences are conversions to void 2120 // pointers. Compare the source types to determine if there's an 2121 // inheritance relationship in their sources. 2122 QualType FromType1 = SCS1.getFromType(); 2123 QualType FromType2 = SCS2.getFromType(); 2124 2125 // Adjust the types we're converting from via the array-to-pointer 2126 // conversion, if we need to. 2127 if (SCS1.First == ICK_Array_To_Pointer) 2128 FromType1 = Context.getArrayDecayedType(FromType1); 2129 if (SCS2.First == ICK_Array_To_Pointer) 2130 FromType2 = Context.getArrayDecayedType(FromType2); 2131 2132 QualType FromPointee1 2133 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2134 QualType FromPointee2 2135 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2136 2137 if (IsDerivedFrom(FromPointee2, FromPointee1)) 2138 return ImplicitConversionSequence::Better; 2139 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 2140 return ImplicitConversionSequence::Worse; 2141 2142 // Objective-C++: If one interface is more specific than the 2143 // other, it is the better one. 2144 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 2145 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 2146 if (FromIface1 && FromIface1) { 2147 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2148 return ImplicitConversionSequence::Better; 2149 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2150 return ImplicitConversionSequence::Worse; 2151 } 2152 } 2153 2154 // Compare based on qualification conversions (C++ 13.3.3.2p3, 2155 // bullet 3). 2156 if (ImplicitConversionSequence::CompareKind QualCK 2157 = CompareQualificationConversions(SCS1, SCS2)) 2158 return QualCK; 2159 2160 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 2161 // C++0x [over.ics.rank]p3b4: 2162 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 2163 // implicit object parameter of a non-static member function declared 2164 // without a ref-qualifier, and S1 binds an rvalue reference to an 2165 // rvalue and S2 binds an lvalue reference. 2166 // FIXME: We don't know if we're dealing with the implicit object parameter, 2167 // or if the member function in this case has a ref qualifier. 2168 // (Of course, we don't have ref qualifiers yet.) 2169 if (SCS1.RRefBinding != SCS2.RRefBinding) 2170 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 2171 : ImplicitConversionSequence::Worse; 2172 2173 // C++ [over.ics.rank]p3b4: 2174 // -- S1 and S2 are reference bindings (8.5.3), and the types to 2175 // which the references refer are the same type except for 2176 // top-level cv-qualifiers, and the type to which the reference 2177 // initialized by S2 refers is more cv-qualified than the type 2178 // to which the reference initialized by S1 refers. 2179 QualType T1 = SCS1.getToType(2); 2180 QualType T2 = SCS2.getToType(2); 2181 T1 = Context.getCanonicalType(T1); 2182 T2 = Context.getCanonicalType(T2); 2183 Qualifiers T1Quals, T2Quals; 2184 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2185 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2186 if (UnqualT1 == UnqualT2) { 2187 // If the type is an array type, promote the element qualifiers to the type 2188 // for comparison. 2189 if (isa<ArrayType>(T1) && T1Quals) 2190 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2191 if (isa<ArrayType>(T2) && T2Quals) 2192 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2193 if (T2.isMoreQualifiedThan(T1)) 2194 return ImplicitConversionSequence::Better; 2195 else if (T1.isMoreQualifiedThan(T2)) 2196 return ImplicitConversionSequence::Worse; 2197 } 2198 } 2199 2200 return ImplicitConversionSequence::Indistinguishable; 2201} 2202 2203/// CompareQualificationConversions - Compares two standard conversion 2204/// sequences to determine whether they can be ranked based on their 2205/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 2206ImplicitConversionSequence::CompareKind 2207Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 2208 const StandardConversionSequence& SCS2) { 2209 // C++ 13.3.3.2p3: 2210 // -- S1 and S2 differ only in their qualification conversion and 2211 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 2212 // cv-qualification signature of type T1 is a proper subset of 2213 // the cv-qualification signature of type T2, and S1 is not the 2214 // deprecated string literal array-to-pointer conversion (4.2). 2215 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 2216 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 2217 return ImplicitConversionSequence::Indistinguishable; 2218 2219 // FIXME: the example in the standard doesn't use a qualification 2220 // conversion (!) 2221 QualType T1 = SCS1.getToType(2); 2222 QualType T2 = SCS2.getToType(2); 2223 T1 = Context.getCanonicalType(T1); 2224 T2 = Context.getCanonicalType(T2); 2225 Qualifiers T1Quals, T2Quals; 2226 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2227 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2228 2229 // If the types are the same, we won't learn anything by unwrapped 2230 // them. 2231 if (UnqualT1 == UnqualT2) 2232 return ImplicitConversionSequence::Indistinguishable; 2233 2234 // If the type is an array type, promote the element qualifiers to the type 2235 // for comparison. 2236 if (isa<ArrayType>(T1) && T1Quals) 2237 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2238 if (isa<ArrayType>(T2) && T2Quals) 2239 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2240 2241 ImplicitConversionSequence::CompareKind Result 2242 = ImplicitConversionSequence::Indistinguishable; 2243 while (UnwrapSimilarPointerTypes(T1, T2)) { 2244 // Within each iteration of the loop, we check the qualifiers to 2245 // determine if this still looks like a qualification 2246 // conversion. Then, if all is well, we unwrap one more level of 2247 // pointers or pointers-to-members and do it all again 2248 // until there are no more pointers or pointers-to-members left 2249 // to unwrap. This essentially mimics what 2250 // IsQualificationConversion does, but here we're checking for a 2251 // strict subset of qualifiers. 2252 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 2253 // The qualifiers are the same, so this doesn't tell us anything 2254 // about how the sequences rank. 2255 ; 2256 else if (T2.isMoreQualifiedThan(T1)) { 2257 // T1 has fewer qualifiers, so it could be the better sequence. 2258 if (Result == ImplicitConversionSequence::Worse) 2259 // Neither has qualifiers that are a subset of the other's 2260 // qualifiers. 2261 return ImplicitConversionSequence::Indistinguishable; 2262 2263 Result = ImplicitConversionSequence::Better; 2264 } else if (T1.isMoreQualifiedThan(T2)) { 2265 // T2 has fewer qualifiers, so it could be the better sequence. 2266 if (Result == ImplicitConversionSequence::Better) 2267 // Neither has qualifiers that are a subset of the other's 2268 // qualifiers. 2269 return ImplicitConversionSequence::Indistinguishable; 2270 2271 Result = ImplicitConversionSequence::Worse; 2272 } else { 2273 // Qualifiers are disjoint. 2274 return ImplicitConversionSequence::Indistinguishable; 2275 } 2276 2277 // If the types after this point are equivalent, we're done. 2278 if (Context.hasSameUnqualifiedType(T1, T2)) 2279 break; 2280 } 2281 2282 // Check that the winning standard conversion sequence isn't using 2283 // the deprecated string literal array to pointer conversion. 2284 switch (Result) { 2285 case ImplicitConversionSequence::Better: 2286 if (SCS1.DeprecatedStringLiteralToCharPtr) 2287 Result = ImplicitConversionSequence::Indistinguishable; 2288 break; 2289 2290 case ImplicitConversionSequence::Indistinguishable: 2291 break; 2292 2293 case ImplicitConversionSequence::Worse: 2294 if (SCS2.DeprecatedStringLiteralToCharPtr) 2295 Result = ImplicitConversionSequence::Indistinguishable; 2296 break; 2297 } 2298 2299 return Result; 2300} 2301 2302/// CompareDerivedToBaseConversions - Compares two standard conversion 2303/// sequences to determine whether they can be ranked based on their 2304/// various kinds of derived-to-base conversions (C++ 2305/// [over.ics.rank]p4b3). As part of these checks, we also look at 2306/// conversions between Objective-C interface types. 2307ImplicitConversionSequence::CompareKind 2308Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 2309 const StandardConversionSequence& SCS2) { 2310 QualType FromType1 = SCS1.getFromType(); 2311 QualType ToType1 = SCS1.getToType(1); 2312 QualType FromType2 = SCS2.getFromType(); 2313 QualType ToType2 = SCS2.getToType(1); 2314 2315 // Adjust the types we're converting from via the array-to-pointer 2316 // conversion, if we need to. 2317 if (SCS1.First == ICK_Array_To_Pointer) 2318 FromType1 = Context.getArrayDecayedType(FromType1); 2319 if (SCS2.First == ICK_Array_To_Pointer) 2320 FromType2 = Context.getArrayDecayedType(FromType2); 2321 2322 // Canonicalize all of the types. 2323 FromType1 = Context.getCanonicalType(FromType1); 2324 ToType1 = Context.getCanonicalType(ToType1); 2325 FromType2 = Context.getCanonicalType(FromType2); 2326 ToType2 = Context.getCanonicalType(ToType2); 2327 2328 // C++ [over.ics.rank]p4b3: 2329 // 2330 // If class B is derived directly or indirectly from class A and 2331 // class C is derived directly or indirectly from B, 2332 // 2333 // For Objective-C, we let A, B, and C also be Objective-C 2334 // interfaces. 2335 2336 // Compare based on pointer conversions. 2337 if (SCS1.Second == ICK_Pointer_Conversion && 2338 SCS2.Second == ICK_Pointer_Conversion && 2339 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 2340 FromType1->isPointerType() && FromType2->isPointerType() && 2341 ToType1->isPointerType() && ToType2->isPointerType()) { 2342 QualType FromPointee1 2343 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2344 QualType ToPointee1 2345 = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2346 QualType FromPointee2 2347 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2348 QualType ToPointee2 2349 = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2350 2351 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 2352 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 2353 const ObjCInterfaceType* ToIface1 = ToPointee1->getAs<ObjCInterfaceType>(); 2354 const ObjCInterfaceType* ToIface2 = ToPointee2->getAs<ObjCInterfaceType>(); 2355 2356 // -- conversion of C* to B* is better than conversion of C* to A*, 2357 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2358 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2359 return ImplicitConversionSequence::Better; 2360 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2361 return ImplicitConversionSequence::Worse; 2362 2363 if (ToIface1 && ToIface2) { 2364 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 2365 return ImplicitConversionSequence::Better; 2366 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 2367 return ImplicitConversionSequence::Worse; 2368 } 2369 } 2370 2371 // -- conversion of B* to A* is better than conversion of C* to A*, 2372 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 2373 if (IsDerivedFrom(FromPointee2, FromPointee1)) 2374 return ImplicitConversionSequence::Better; 2375 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 2376 return ImplicitConversionSequence::Worse; 2377 2378 if (FromIface1 && FromIface2) { 2379 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2380 return ImplicitConversionSequence::Better; 2381 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2382 return ImplicitConversionSequence::Worse; 2383 } 2384 } 2385 } 2386 2387 // Ranking of member-pointer types. 2388 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && 2389 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && 2390 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { 2391 const MemberPointerType * FromMemPointer1 = 2392 FromType1->getAs<MemberPointerType>(); 2393 const MemberPointerType * ToMemPointer1 = 2394 ToType1->getAs<MemberPointerType>(); 2395 const MemberPointerType * FromMemPointer2 = 2396 FromType2->getAs<MemberPointerType>(); 2397 const MemberPointerType * ToMemPointer2 = 2398 ToType2->getAs<MemberPointerType>(); 2399 const Type *FromPointeeType1 = FromMemPointer1->getClass(); 2400 const Type *ToPointeeType1 = ToMemPointer1->getClass(); 2401 const Type *FromPointeeType2 = FromMemPointer2->getClass(); 2402 const Type *ToPointeeType2 = ToMemPointer2->getClass(); 2403 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); 2404 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); 2405 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); 2406 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); 2407 // conversion of A::* to B::* is better than conversion of A::* to C::*, 2408 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2409 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2410 return ImplicitConversionSequence::Worse; 2411 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2412 return ImplicitConversionSequence::Better; 2413 } 2414 // conversion of B::* to C::* is better than conversion of A::* to C::* 2415 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { 2416 if (IsDerivedFrom(FromPointee1, FromPointee2)) 2417 return ImplicitConversionSequence::Better; 2418 else if (IsDerivedFrom(FromPointee2, FromPointee1)) 2419 return ImplicitConversionSequence::Worse; 2420 } 2421 } 2422 2423 if (SCS1.Second == ICK_Derived_To_Base) { 2424 // -- conversion of C to B is better than conversion of C to A, 2425 // -- binding of an expression of type C to a reference of type 2426 // B& is better than binding an expression of type C to a 2427 // reference of type A&, 2428 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2429 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2430 if (IsDerivedFrom(ToType1, ToType2)) 2431 return ImplicitConversionSequence::Better; 2432 else if (IsDerivedFrom(ToType2, ToType1)) 2433 return ImplicitConversionSequence::Worse; 2434 } 2435 2436 // -- conversion of B to A is better than conversion of C to A. 2437 // -- binding of an expression of type B to a reference of type 2438 // A& is better than binding an expression of type C to a 2439 // reference of type A&, 2440 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2441 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2442 if (IsDerivedFrom(FromType2, FromType1)) 2443 return ImplicitConversionSequence::Better; 2444 else if (IsDerivedFrom(FromType1, FromType2)) 2445 return ImplicitConversionSequence::Worse; 2446 } 2447 } 2448 2449 return ImplicitConversionSequence::Indistinguishable; 2450} 2451 2452/// CompareReferenceRelationship - Compare the two types T1 and T2 to 2453/// determine whether they are reference-related, 2454/// reference-compatible, reference-compatible with added 2455/// qualification, or incompatible, for use in C++ initialization by 2456/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 2457/// type, and the first type (T1) is the pointee type of the reference 2458/// type being initialized. 2459Sema::ReferenceCompareResult 2460Sema::CompareReferenceRelationship(SourceLocation Loc, 2461 QualType OrigT1, QualType OrigT2, 2462 bool& DerivedToBase) { 2463 assert(!OrigT1->isReferenceType() && 2464 "T1 must be the pointee type of the reference type"); 2465 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); 2466 2467 QualType T1 = Context.getCanonicalType(OrigT1); 2468 QualType T2 = Context.getCanonicalType(OrigT2); 2469 Qualifiers T1Quals, T2Quals; 2470 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2471 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2472 2473 // C++ [dcl.init.ref]p4: 2474 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is 2475 // reference-related to "cv2 T2" if T1 is the same type as T2, or 2476 // T1 is a base class of T2. 2477 if (UnqualT1 == UnqualT2) 2478 DerivedToBase = false; 2479 else if (!RequireCompleteType(Loc, OrigT2, PDiag()) && 2480 IsDerivedFrom(UnqualT2, UnqualT1)) 2481 DerivedToBase = true; 2482 else 2483 return Ref_Incompatible; 2484 2485 // At this point, we know that T1 and T2 are reference-related (at 2486 // least). 2487 2488 // If the type is an array type, promote the element qualifiers to the type 2489 // for comparison. 2490 if (isa<ArrayType>(T1) && T1Quals) 2491 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2492 if (isa<ArrayType>(T2) && T2Quals) 2493 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2494 2495 // C++ [dcl.init.ref]p4: 2496 // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is 2497 // reference-related to T2 and cv1 is the same cv-qualification 2498 // as, or greater cv-qualification than, cv2. For purposes of 2499 // overload resolution, cases for which cv1 is greater 2500 // cv-qualification than cv2 are identified as 2501 // reference-compatible with added qualification (see 13.3.3.2). 2502 if (T1Quals.getCVRQualifiers() == T2Quals.getCVRQualifiers()) 2503 return Ref_Compatible; 2504 else if (T1.isMoreQualifiedThan(T2)) 2505 return Ref_Compatible_With_Added_Qualification; 2506 else 2507 return Ref_Related; 2508} 2509 2510/// \brief Compute an implicit conversion sequence for reference 2511/// initialization. 2512static ImplicitConversionSequence 2513TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType, 2514 SourceLocation DeclLoc, 2515 bool SuppressUserConversions, 2516 bool AllowExplicit) { 2517 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 2518 2519 // Most paths end in a failed conversion. 2520 ImplicitConversionSequence ICS; 2521 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); 2522 2523 QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType(); 2524 QualType T2 = Init->getType(); 2525 2526 // If the initializer is the address of an overloaded function, try 2527 // to resolve the overloaded function. If all goes well, T2 is the 2528 // type of the resulting function. 2529 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { 2530 DeclAccessPair Found; 2531 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, 2532 false, Found)) 2533 T2 = Fn->getType(); 2534 } 2535 2536 // Compute some basic properties of the types and the initializer. 2537 bool isRValRef = DeclType->isRValueReferenceType(); 2538 bool DerivedToBase = false; 2539 Expr::isLvalueResult InitLvalue = Init->isLvalue(S.Context); 2540 Sema::ReferenceCompareResult RefRelationship 2541 = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase); 2542 2543 2544 // C++ [over.ics.ref]p3: 2545 // Except for an implicit object parameter, for which see 13.3.1, 2546 // a standard conversion sequence cannot be formed if it requires 2547 // binding an lvalue reference to non-const to an rvalue or 2548 // binding an rvalue reference to an lvalue. 2549 // 2550 // FIXME: DPG doesn't trust this code. It seems far too early to 2551 // abort because of a binding of an rvalue reference to an lvalue. 2552 if (isRValRef && InitLvalue == Expr::LV_Valid) 2553 return ICS; 2554 2555 // C++0x [dcl.init.ref]p16: 2556 // A reference to type "cv1 T1" is initialized by an expression 2557 // of type "cv2 T2" as follows: 2558 2559 // -- If the initializer expression 2560 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is 2561 // reference-compatible with "cv2 T2," or 2562 // 2563 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. 2564 if (InitLvalue == Expr::LV_Valid && 2565 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2566 // C++ [over.ics.ref]p1: 2567 // When a parameter of reference type binds directly (8.5.3) 2568 // to an argument expression, the implicit conversion sequence 2569 // is the identity conversion, unless the argument expression 2570 // has a type that is a derived class of the parameter type, 2571 // in which case the implicit conversion sequence is a 2572 // derived-to-base Conversion (13.3.3.1). 2573 ICS.setStandard(); 2574 ICS.Standard.First = ICK_Identity; 2575 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2576 ICS.Standard.Third = ICK_Identity; 2577 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2578 ICS.Standard.setToType(0, T2); 2579 ICS.Standard.setToType(1, T1); 2580 ICS.Standard.setToType(2, T1); 2581 ICS.Standard.ReferenceBinding = true; 2582 ICS.Standard.DirectBinding = true; 2583 ICS.Standard.RRefBinding = false; 2584 ICS.Standard.CopyConstructor = 0; 2585 2586 // Nothing more to do: the inaccessibility/ambiguity check for 2587 // derived-to-base conversions is suppressed when we're 2588 // computing the implicit conversion sequence (C++ 2589 // [over.best.ics]p2). 2590 return ICS; 2591 } 2592 2593 // -- has a class type (i.e., T2 is a class type), where T1 is 2594 // not reference-related to T2, and can be implicitly 2595 // converted to an lvalue of type "cv3 T3," where "cv1 T1" 2596 // is reference-compatible with "cv3 T3" 92) (this 2597 // conversion is selected by enumerating the applicable 2598 // conversion functions (13.3.1.6) and choosing the best 2599 // one through overload resolution (13.3)), 2600 if (!isRValRef && !SuppressUserConversions && T2->isRecordType() && 2601 !S.RequireCompleteType(DeclLoc, T2, 0) && 2602 RefRelationship == Sema::Ref_Incompatible) { 2603 CXXRecordDecl *T2RecordDecl 2604 = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl()); 2605 2606 OverloadCandidateSet CandidateSet(DeclLoc); 2607 const UnresolvedSetImpl *Conversions 2608 = T2RecordDecl->getVisibleConversionFunctions(); 2609 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 2610 E = Conversions->end(); I != E; ++I) { 2611 NamedDecl *D = *I; 2612 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext()); 2613 if (isa<UsingShadowDecl>(D)) 2614 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 2615 2616 FunctionTemplateDecl *ConvTemplate 2617 = dyn_cast<FunctionTemplateDecl>(D); 2618 CXXConversionDecl *Conv; 2619 if (ConvTemplate) 2620 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 2621 else 2622 Conv = cast<CXXConversionDecl>(D); 2623 2624 // If the conversion function doesn't return a reference type, 2625 // it can't be considered for this conversion. 2626 if (Conv->getConversionType()->isLValueReferenceType() && 2627 (AllowExplicit || !Conv->isExplicit())) { 2628 if (ConvTemplate) 2629 S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC, 2630 Init, DeclType, CandidateSet); 2631 else 2632 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init, 2633 DeclType, CandidateSet); 2634 } 2635 } 2636 2637 OverloadCandidateSet::iterator Best; 2638 switch (S.BestViableFunction(CandidateSet, DeclLoc, Best)) { 2639 case OR_Success: 2640 // C++ [over.ics.ref]p1: 2641 // 2642 // [...] If the parameter binds directly to the result of 2643 // applying a conversion function to the argument 2644 // expression, the implicit conversion sequence is a 2645 // user-defined conversion sequence (13.3.3.1.2), with the 2646 // second standard conversion sequence either an identity 2647 // conversion or, if the conversion function returns an 2648 // entity of a type that is a derived class of the parameter 2649 // type, a derived-to-base Conversion. 2650 if (!Best->FinalConversion.DirectBinding) 2651 break; 2652 2653 ICS.setUserDefined(); 2654 ICS.UserDefined.Before = Best->Conversions[0].Standard; 2655 ICS.UserDefined.After = Best->FinalConversion; 2656 ICS.UserDefined.ConversionFunction = Best->Function; 2657 ICS.UserDefined.EllipsisConversion = false; 2658 assert(ICS.UserDefined.After.ReferenceBinding && 2659 ICS.UserDefined.After.DirectBinding && 2660 "Expected a direct reference binding!"); 2661 return ICS; 2662 2663 case OR_Ambiguous: 2664 ICS.setAmbiguous(); 2665 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 2666 Cand != CandidateSet.end(); ++Cand) 2667 if (Cand->Viable) 2668 ICS.Ambiguous.addConversion(Cand->Function); 2669 return ICS; 2670 2671 case OR_No_Viable_Function: 2672 case OR_Deleted: 2673 // There was no suitable conversion, or we found a deleted 2674 // conversion; continue with other checks. 2675 break; 2676 } 2677 } 2678 2679 // -- Otherwise, the reference shall be to a non-volatile const 2680 // type (i.e., cv1 shall be const), or the reference shall be an 2681 // rvalue reference and the initializer expression shall be an rvalue. 2682 // 2683 // We actually handle one oddity of C++ [over.ics.ref] at this 2684 // point, which is that, due to p2 (which short-circuits reference 2685 // binding by only attempting a simple conversion for non-direct 2686 // bindings) and p3's strange wording, we allow a const volatile 2687 // reference to bind to an rvalue. Hence the check for the presence 2688 // of "const" rather than checking for "const" being the only 2689 // qualifier. 2690 if (!isRValRef && !T1.isConstQualified()) 2691 return ICS; 2692 2693 // -- if T2 is a class type and 2694 // -- the initializer expression is an rvalue and "cv1 T1" 2695 // is reference-compatible with "cv2 T2," or 2696 // 2697 // -- T1 is not reference-related to T2 and the initializer 2698 // expression can be implicitly converted to an rvalue 2699 // of type "cv3 T3" (this conversion is selected by 2700 // enumerating the applicable conversion functions 2701 // (13.3.1.6) and choosing the best one through overload 2702 // resolution (13.3)), 2703 // 2704 // then the reference is bound to the initializer 2705 // expression rvalue in the first case and to the object 2706 // that is the result of the conversion in the second case 2707 // (or, in either case, to the appropriate base class 2708 // subobject of the object). 2709 // 2710 // We're only checking the first case here, which is a direct 2711 // binding in C++0x but not in C++03. 2712 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 2713 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2714 ICS.setStandard(); 2715 ICS.Standard.First = ICK_Identity; 2716 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2717 ICS.Standard.Third = ICK_Identity; 2718 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2719 ICS.Standard.setToType(0, T2); 2720 ICS.Standard.setToType(1, T1); 2721 ICS.Standard.setToType(2, T1); 2722 ICS.Standard.ReferenceBinding = true; 2723 ICS.Standard.DirectBinding = S.getLangOptions().CPlusPlus0x; 2724 ICS.Standard.RRefBinding = isRValRef; 2725 ICS.Standard.CopyConstructor = 0; 2726 return ICS; 2727 } 2728 2729 // -- Otherwise, a temporary of type "cv1 T1" is created and 2730 // initialized from the initializer expression using the 2731 // rules for a non-reference copy initialization (8.5). The 2732 // reference is then bound to the temporary. If T1 is 2733 // reference-related to T2, cv1 must be the same 2734 // cv-qualification as, or greater cv-qualification than, 2735 // cv2; otherwise, the program is ill-formed. 2736 if (RefRelationship == Sema::Ref_Related) { 2737 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 2738 // we would be reference-compatible or reference-compatible with 2739 // added qualification. But that wasn't the case, so the reference 2740 // initialization fails. 2741 return ICS; 2742 } 2743 2744 // If at least one of the types is a class type, the types are not 2745 // related, and we aren't allowed any user conversions, the 2746 // reference binding fails. This case is important for breaking 2747 // recursion, since TryImplicitConversion below will attempt to 2748 // create a temporary through the use of a copy constructor. 2749 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && 2750 (T1->isRecordType() || T2->isRecordType())) 2751 return ICS; 2752 2753 // C++ [over.ics.ref]p2: 2754 // When a parameter of reference type is not bound directly to 2755 // an argument expression, the conversion sequence is the one 2756 // required to convert the argument expression to the 2757 // underlying type of the reference according to 2758 // 13.3.3.1. Conceptually, this conversion sequence corresponds 2759 // to copy-initializing a temporary of the underlying type with 2760 // the argument expression. Any difference in top-level 2761 // cv-qualification is subsumed by the initialization itself 2762 // and does not constitute a conversion. 2763 ICS = S.TryImplicitConversion(Init, T1, SuppressUserConversions, 2764 /*AllowExplicit=*/false, 2765 /*InOverloadResolution=*/false); 2766 2767 // Of course, that's still a reference binding. 2768 if (ICS.isStandard()) { 2769 ICS.Standard.ReferenceBinding = true; 2770 ICS.Standard.RRefBinding = isRValRef; 2771 } else if (ICS.isUserDefined()) { 2772 ICS.UserDefined.After.ReferenceBinding = true; 2773 ICS.UserDefined.After.RRefBinding = isRValRef; 2774 } 2775 return ICS; 2776} 2777 2778/// TryCopyInitialization - Try to copy-initialize a value of type 2779/// ToType from the expression From. Return the implicit conversion 2780/// sequence required to pass this argument, which may be a bad 2781/// conversion sequence (meaning that the argument cannot be passed to 2782/// a parameter of this type). If @p SuppressUserConversions, then we 2783/// do not permit any user-defined conversion sequences. 2784static ImplicitConversionSequence 2785TryCopyInitialization(Sema &S, Expr *From, QualType ToType, 2786 bool SuppressUserConversions, 2787 bool InOverloadResolution) { 2788 if (ToType->isReferenceType()) 2789 return TryReferenceInit(S, From, ToType, 2790 /*FIXME:*/From->getLocStart(), 2791 SuppressUserConversions, 2792 /*AllowExplicit=*/false); 2793 2794 return S.TryImplicitConversion(From, ToType, 2795 SuppressUserConversions, 2796 /*AllowExplicit=*/false, 2797 InOverloadResolution); 2798} 2799 2800/// TryObjectArgumentInitialization - Try to initialize the object 2801/// parameter of the given member function (@c Method) from the 2802/// expression @p From. 2803ImplicitConversionSequence 2804Sema::TryObjectArgumentInitialization(QualType OrigFromType, 2805 CXXMethodDecl *Method, 2806 CXXRecordDecl *ActingContext) { 2807 QualType ClassType = Context.getTypeDeclType(ActingContext); 2808 // [class.dtor]p2: A destructor can be invoked for a const, volatile or 2809 // const volatile object. 2810 unsigned Quals = isa<CXXDestructorDecl>(Method) ? 2811 Qualifiers::Const | Qualifiers::Volatile : Method->getTypeQualifiers(); 2812 QualType ImplicitParamType = Context.getCVRQualifiedType(ClassType, Quals); 2813 2814 // Set up the conversion sequence as a "bad" conversion, to allow us 2815 // to exit early. 2816 ImplicitConversionSequence ICS; 2817 2818 // We need to have an object of class type. 2819 QualType FromType = OrigFromType; 2820 if (const PointerType *PT = FromType->getAs<PointerType>()) 2821 FromType = PT->getPointeeType(); 2822 2823 assert(FromType->isRecordType()); 2824 2825 // The implicit object parameter is has the type "reference to cv X", 2826 // where X is the class of which the function is a member 2827 // (C++ [over.match.funcs]p4). However, when finding an implicit 2828 // conversion sequence for the argument, we are not allowed to 2829 // create temporaries or perform user-defined conversions 2830 // (C++ [over.match.funcs]p5). We perform a simplified version of 2831 // reference binding here, that allows class rvalues to bind to 2832 // non-constant references. 2833 2834 // First check the qualifiers. We don't care about lvalue-vs-rvalue 2835 // with the implicit object parameter (C++ [over.match.funcs]p5). 2836 QualType FromTypeCanon = Context.getCanonicalType(FromType); 2837 if (ImplicitParamType.getCVRQualifiers() 2838 != FromTypeCanon.getLocalCVRQualifiers() && 2839 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { 2840 ICS.setBad(BadConversionSequence::bad_qualifiers, 2841 OrigFromType, ImplicitParamType); 2842 return ICS; 2843 } 2844 2845 // Check that we have either the same type or a derived type. It 2846 // affects the conversion rank. 2847 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 2848 ImplicitConversionKind SecondKind; 2849 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { 2850 SecondKind = ICK_Identity; 2851 } else if (IsDerivedFrom(FromType, ClassType)) 2852 SecondKind = ICK_Derived_To_Base; 2853 else { 2854 ICS.setBad(BadConversionSequence::unrelated_class, 2855 FromType, ImplicitParamType); 2856 return ICS; 2857 } 2858 2859 // Success. Mark this as a reference binding. 2860 ICS.setStandard(); 2861 ICS.Standard.setAsIdentityConversion(); 2862 ICS.Standard.Second = SecondKind; 2863 ICS.Standard.setFromType(FromType); 2864 ICS.Standard.setAllToTypes(ImplicitParamType); 2865 ICS.Standard.ReferenceBinding = true; 2866 ICS.Standard.DirectBinding = true; 2867 ICS.Standard.RRefBinding = false; 2868 return ICS; 2869} 2870 2871/// PerformObjectArgumentInitialization - Perform initialization of 2872/// the implicit object parameter for the given Method with the given 2873/// expression. 2874bool 2875Sema::PerformObjectArgumentInitialization(Expr *&From, 2876 NestedNameSpecifier *Qualifier, 2877 NamedDecl *FoundDecl, 2878 CXXMethodDecl *Method) { 2879 QualType FromRecordType, DestType; 2880 QualType ImplicitParamRecordType = 2881 Method->getThisType(Context)->getAs<PointerType>()->getPointeeType(); 2882 2883 if (const PointerType *PT = From->getType()->getAs<PointerType>()) { 2884 FromRecordType = PT->getPointeeType(); 2885 DestType = Method->getThisType(Context); 2886 } else { 2887 FromRecordType = From->getType(); 2888 DestType = ImplicitParamRecordType; 2889 } 2890 2891 // Note that we always use the true parent context when performing 2892 // the actual argument initialization. 2893 ImplicitConversionSequence ICS 2894 = TryObjectArgumentInitialization(From->getType(), Method, 2895 Method->getParent()); 2896 if (ICS.isBad()) 2897 return Diag(From->getSourceRange().getBegin(), 2898 diag::err_implicit_object_parameter_init) 2899 << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); 2900 2901 if (ICS.Standard.Second == ICK_Derived_To_Base) 2902 return PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); 2903 2904 if (!Context.hasSameType(From->getType(), DestType)) 2905 ImpCastExprToType(From, DestType, CastExpr::CK_NoOp, 2906 /*isLvalue=*/!From->getType()->isPointerType()); 2907 return false; 2908} 2909 2910/// TryContextuallyConvertToBool - Attempt to contextually convert the 2911/// expression From to bool (C++0x [conv]p3). 2912ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 2913 // FIXME: This is pretty broken. 2914 return TryImplicitConversion(From, Context.BoolTy, 2915 // FIXME: Are these flags correct? 2916 /*SuppressUserConversions=*/false, 2917 /*AllowExplicit=*/true, 2918 /*InOverloadResolution=*/false); 2919} 2920 2921/// PerformContextuallyConvertToBool - Perform a contextual conversion 2922/// of the expression From to bool (C++0x [conv]p3). 2923bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2924 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2925 if (!ICS.isBad()) 2926 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); 2927 2928 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2929 return Diag(From->getSourceRange().getBegin(), 2930 diag::err_typecheck_bool_condition) 2931 << From->getType() << From->getSourceRange(); 2932 return true; 2933} 2934 2935/// AddOverloadCandidate - Adds the given function to the set of 2936/// candidate functions, using the given function call arguments. If 2937/// @p SuppressUserConversions, then don't allow user-defined 2938/// conversions via constructors or conversion operators. 2939/// 2940/// \para PartialOverloading true if we are performing "partial" overloading 2941/// based on an incomplete set of function arguments. This feature is used by 2942/// code completion. 2943void 2944Sema::AddOverloadCandidate(FunctionDecl *Function, 2945 DeclAccessPair FoundDecl, 2946 Expr **Args, unsigned NumArgs, 2947 OverloadCandidateSet& CandidateSet, 2948 bool SuppressUserConversions, 2949 bool PartialOverloading) { 2950 const FunctionProtoType* Proto 2951 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2952 assert(Proto && "Functions without a prototype cannot be overloaded"); 2953 assert(!Function->getDescribedFunctionTemplate() && 2954 "Use AddTemplateOverloadCandidate for function templates"); 2955 2956 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2957 if (!isa<CXXConstructorDecl>(Method)) { 2958 // If we get here, it's because we're calling a member function 2959 // that is named without a member access expression (e.g., 2960 // "this->f") that was either written explicitly or created 2961 // implicitly. This can happen with a qualified call to a member 2962 // function, e.g., X::f(). We use an empty type for the implied 2963 // object argument (C++ [over.call.func]p3), and the acting context 2964 // is irrelevant. 2965 AddMethodCandidate(Method, FoundDecl, Method->getParent(), 2966 QualType(), Args, NumArgs, CandidateSet, 2967 SuppressUserConversions); 2968 return; 2969 } 2970 // We treat a constructor like a non-member function, since its object 2971 // argument doesn't participate in overload resolution. 2972 } 2973 2974 if (!CandidateSet.isNewCandidate(Function)) 2975 return; 2976 2977 // Overload resolution is always an unevaluated context. 2978 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2979 2980 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2981 // C++ [class.copy]p3: 2982 // A member function template is never instantiated to perform the copy 2983 // of a class object to an object of its class type. 2984 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2985 if (NumArgs == 1 && 2986 Constructor->isCopyConstructorLikeSpecialization() && 2987 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || 2988 IsDerivedFrom(Args[0]->getType(), ClassType))) 2989 return; 2990 } 2991 2992 // Add this candidate 2993 CandidateSet.push_back(OverloadCandidate()); 2994 OverloadCandidate& Candidate = CandidateSet.back(); 2995 Candidate.FoundDecl = FoundDecl; 2996 Candidate.Function = Function; 2997 Candidate.Viable = true; 2998 Candidate.IsSurrogate = false; 2999 Candidate.IgnoreObjectArgument = false; 3000 3001 unsigned NumArgsInProto = Proto->getNumArgs(); 3002 3003 // (C++ 13.3.2p2): A candidate function having fewer than m 3004 // parameters is viable only if it has an ellipsis in its parameter 3005 // list (8.3.5). 3006 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 3007 !Proto->isVariadic()) { 3008 Candidate.Viable = false; 3009 Candidate.FailureKind = ovl_fail_too_many_arguments; 3010 return; 3011 } 3012 3013 // (C++ 13.3.2p2): A candidate function having more than m parameters 3014 // is viable only if the (m+1)st parameter has a default argument 3015 // (8.3.6). For the purposes of overload resolution, the 3016 // parameter list is truncated on the right, so that there are 3017 // exactly m parameters. 3018 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 3019 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 3020 // Not enough arguments. 3021 Candidate.Viable = false; 3022 Candidate.FailureKind = ovl_fail_too_few_arguments; 3023 return; 3024 } 3025 3026 // Determine the implicit conversion sequences for each of the 3027 // arguments. 3028 Candidate.Conversions.resize(NumArgs); 3029 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3030 if (ArgIdx < NumArgsInProto) { 3031 // (C++ 13.3.2p3): for F to be a viable function, there shall 3032 // exist for each argument an implicit conversion sequence 3033 // (13.3.3.1) that converts that argument to the corresponding 3034 // parameter of F. 3035 QualType ParamType = Proto->getArgType(ArgIdx); 3036 Candidate.Conversions[ArgIdx] 3037 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3038 SuppressUserConversions, 3039 /*InOverloadResolution=*/true); 3040 if (Candidate.Conversions[ArgIdx].isBad()) { 3041 Candidate.Viable = false; 3042 Candidate.FailureKind = ovl_fail_bad_conversion; 3043 break; 3044 } 3045 } else { 3046 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3047 // argument for which there is no corresponding parameter is 3048 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3049 Candidate.Conversions[ArgIdx].setEllipsis(); 3050 } 3051 } 3052} 3053 3054/// \brief Add all of the function declarations in the given function set to 3055/// the overload canddiate set. 3056void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, 3057 Expr **Args, unsigned NumArgs, 3058 OverloadCandidateSet& CandidateSet, 3059 bool SuppressUserConversions) { 3060 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { 3061 NamedDecl *D = F.getDecl()->getUnderlyingDecl(); 3062 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 3063 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 3064 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), 3065 cast<CXXMethodDecl>(FD)->getParent(), 3066 Args[0]->getType(), Args + 1, NumArgs - 1, 3067 CandidateSet, SuppressUserConversions); 3068 else 3069 AddOverloadCandidate(FD, F.getPair(), Args, NumArgs, CandidateSet, 3070 SuppressUserConversions); 3071 } else { 3072 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D); 3073 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 3074 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 3075 AddMethodTemplateCandidate(FunTmpl, F.getPair(), 3076 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 3077 /*FIXME: explicit args */ 0, 3078 Args[0]->getType(), Args + 1, NumArgs - 1, 3079 CandidateSet, 3080 SuppressUserConversions); 3081 else 3082 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), 3083 /*FIXME: explicit args */ 0, 3084 Args, NumArgs, CandidateSet, 3085 SuppressUserConversions); 3086 } 3087 } 3088} 3089 3090/// AddMethodCandidate - Adds a named decl (which is some kind of 3091/// method) as a method candidate to the given overload set. 3092void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, 3093 QualType ObjectType, 3094 Expr **Args, unsigned NumArgs, 3095 OverloadCandidateSet& CandidateSet, 3096 bool SuppressUserConversions) { 3097 NamedDecl *Decl = FoundDecl.getDecl(); 3098 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 3099 3100 if (isa<UsingShadowDecl>(Decl)) 3101 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 3102 3103 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 3104 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 3105 "Expected a member function template"); 3106 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, 3107 /*ExplicitArgs*/ 0, 3108 ObjectType, Args, NumArgs, 3109 CandidateSet, 3110 SuppressUserConversions); 3111 } else { 3112 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, 3113 ObjectType, Args, NumArgs, 3114 CandidateSet, SuppressUserConversions); 3115 } 3116} 3117 3118/// AddMethodCandidate - Adds the given C++ member function to the set 3119/// of candidate functions, using the given function call arguments 3120/// and the object argument (@c Object). For example, in a call 3121/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 3122/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 3123/// allow user-defined conversions via constructors or conversion 3124/// operators. 3125void 3126Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, 3127 CXXRecordDecl *ActingContext, QualType ObjectType, 3128 Expr **Args, unsigned NumArgs, 3129 OverloadCandidateSet& CandidateSet, 3130 bool SuppressUserConversions) { 3131 const FunctionProtoType* Proto 3132 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 3133 assert(Proto && "Methods without a prototype cannot be overloaded"); 3134 assert(!isa<CXXConstructorDecl>(Method) && 3135 "Use AddOverloadCandidate for constructors"); 3136 3137 if (!CandidateSet.isNewCandidate(Method)) 3138 return; 3139 3140 // Overload resolution is always an unevaluated context. 3141 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3142 3143 // Add this candidate 3144 CandidateSet.push_back(OverloadCandidate()); 3145 OverloadCandidate& Candidate = CandidateSet.back(); 3146 Candidate.FoundDecl = FoundDecl; 3147 Candidate.Function = Method; 3148 Candidate.IsSurrogate = false; 3149 Candidate.IgnoreObjectArgument = false; 3150 3151 unsigned NumArgsInProto = Proto->getNumArgs(); 3152 3153 // (C++ 13.3.2p2): A candidate function having fewer than m 3154 // parameters is viable only if it has an ellipsis in its parameter 3155 // list (8.3.5). 3156 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3157 Candidate.Viable = false; 3158 Candidate.FailureKind = ovl_fail_too_many_arguments; 3159 return; 3160 } 3161 3162 // (C++ 13.3.2p2): A candidate function having more than m parameters 3163 // is viable only if the (m+1)st parameter has a default argument 3164 // (8.3.6). For the purposes of overload resolution, the 3165 // parameter list is truncated on the right, so that there are 3166 // exactly m parameters. 3167 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 3168 if (NumArgs < MinRequiredArgs) { 3169 // Not enough arguments. 3170 Candidate.Viable = false; 3171 Candidate.FailureKind = ovl_fail_too_few_arguments; 3172 return; 3173 } 3174 3175 Candidate.Viable = true; 3176 Candidate.Conversions.resize(NumArgs + 1); 3177 3178 if (Method->isStatic() || ObjectType.isNull()) 3179 // The implicit object argument is ignored. 3180 Candidate.IgnoreObjectArgument = true; 3181 else { 3182 // Determine the implicit conversion sequence for the object 3183 // parameter. 3184 Candidate.Conversions[0] 3185 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 3186 if (Candidate.Conversions[0].isBad()) { 3187 Candidate.Viable = false; 3188 Candidate.FailureKind = ovl_fail_bad_conversion; 3189 return; 3190 } 3191 } 3192 3193 // Determine the implicit conversion sequences for each of the 3194 // arguments. 3195 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3196 if (ArgIdx < NumArgsInProto) { 3197 // (C++ 13.3.2p3): for F to be a viable function, there shall 3198 // exist for each argument an implicit conversion sequence 3199 // (13.3.3.1) that converts that argument to the corresponding 3200 // parameter of F. 3201 QualType ParamType = Proto->getArgType(ArgIdx); 3202 Candidate.Conversions[ArgIdx + 1] 3203 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3204 SuppressUserConversions, 3205 /*InOverloadResolution=*/true); 3206 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3207 Candidate.Viable = false; 3208 Candidate.FailureKind = ovl_fail_bad_conversion; 3209 break; 3210 } 3211 } else { 3212 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3213 // argument for which there is no corresponding parameter is 3214 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3215 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3216 } 3217 } 3218} 3219 3220/// \brief Add a C++ member function template as a candidate to the candidate 3221/// set, using template argument deduction to produce an appropriate member 3222/// function template specialization. 3223void 3224Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 3225 DeclAccessPair FoundDecl, 3226 CXXRecordDecl *ActingContext, 3227 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3228 QualType ObjectType, 3229 Expr **Args, unsigned NumArgs, 3230 OverloadCandidateSet& CandidateSet, 3231 bool SuppressUserConversions) { 3232 if (!CandidateSet.isNewCandidate(MethodTmpl)) 3233 return; 3234 3235 // C++ [over.match.funcs]p7: 3236 // In each case where a candidate is a function template, candidate 3237 // function template specializations are generated using template argument 3238 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3239 // candidate functions in the usual way.113) A given name can refer to one 3240 // or more function templates and also to a set of overloaded non-template 3241 // functions. In such a case, the candidate functions generated from each 3242 // function template are combined with the set of non-template candidate 3243 // functions. 3244 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3245 FunctionDecl *Specialization = 0; 3246 if (TemplateDeductionResult Result 3247 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 3248 Args, NumArgs, Specialization, Info)) { 3249 CandidateSet.push_back(OverloadCandidate()); 3250 OverloadCandidate &Candidate = CandidateSet.back(); 3251 Candidate.FoundDecl = FoundDecl; 3252 Candidate.Function = MethodTmpl->getTemplatedDecl(); 3253 Candidate.Viable = false; 3254 Candidate.FailureKind = ovl_fail_bad_deduction; 3255 Candidate.IsSurrogate = false; 3256 Candidate.IgnoreObjectArgument = false; 3257 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3258 Info); 3259 return; 3260 } 3261 3262 // Add the function template specialization produced by template argument 3263 // deduction as a candidate. 3264 assert(Specialization && "Missing member function template specialization?"); 3265 assert(isa<CXXMethodDecl>(Specialization) && 3266 "Specialization is not a member function?"); 3267 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl, 3268 ActingContext, ObjectType, Args, NumArgs, 3269 CandidateSet, SuppressUserConversions); 3270} 3271 3272/// \brief Add a C++ function template specialization as a candidate 3273/// in the candidate set, using template argument deduction to produce 3274/// an appropriate function template specialization. 3275void 3276Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 3277 DeclAccessPair FoundDecl, 3278 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3279 Expr **Args, unsigned NumArgs, 3280 OverloadCandidateSet& CandidateSet, 3281 bool SuppressUserConversions) { 3282 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3283 return; 3284 3285 // C++ [over.match.funcs]p7: 3286 // In each case where a candidate is a function template, candidate 3287 // function template specializations are generated using template argument 3288 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3289 // candidate functions in the usual way.113) A given name can refer to one 3290 // or more function templates and also to a set of overloaded non-template 3291 // functions. In such a case, the candidate functions generated from each 3292 // function template are combined with the set of non-template candidate 3293 // functions. 3294 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3295 FunctionDecl *Specialization = 0; 3296 if (TemplateDeductionResult Result 3297 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3298 Args, NumArgs, Specialization, Info)) { 3299 CandidateSet.push_back(OverloadCandidate()); 3300 OverloadCandidate &Candidate = CandidateSet.back(); 3301 Candidate.FoundDecl = FoundDecl; 3302 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3303 Candidate.Viable = false; 3304 Candidate.FailureKind = ovl_fail_bad_deduction; 3305 Candidate.IsSurrogate = false; 3306 Candidate.IgnoreObjectArgument = false; 3307 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3308 Info); 3309 return; 3310 } 3311 3312 // Add the function template specialization produced by template argument 3313 // deduction as a candidate. 3314 assert(Specialization && "Missing function template specialization?"); 3315 AddOverloadCandidate(Specialization, FoundDecl, Args, NumArgs, CandidateSet, 3316 SuppressUserConversions); 3317} 3318 3319/// AddConversionCandidate - Add a C++ conversion function as a 3320/// candidate in the candidate set (C++ [over.match.conv], 3321/// C++ [over.match.copy]). From is the expression we're converting from, 3322/// and ToType is the type that we're eventually trying to convert to 3323/// (which may or may not be the same type as the type that the 3324/// conversion function produces). 3325void 3326Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 3327 DeclAccessPair FoundDecl, 3328 CXXRecordDecl *ActingContext, 3329 Expr *From, QualType ToType, 3330 OverloadCandidateSet& CandidateSet) { 3331 assert(!Conversion->getDescribedFunctionTemplate() && 3332 "Conversion function templates use AddTemplateConversionCandidate"); 3333 QualType ConvType = Conversion->getConversionType().getNonReferenceType(); 3334 if (!CandidateSet.isNewCandidate(Conversion)) 3335 return; 3336 3337 // Overload resolution is always an unevaluated context. 3338 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3339 3340 // Add this candidate 3341 CandidateSet.push_back(OverloadCandidate()); 3342 OverloadCandidate& Candidate = CandidateSet.back(); 3343 Candidate.FoundDecl = FoundDecl; 3344 Candidate.Function = Conversion; 3345 Candidate.IsSurrogate = false; 3346 Candidate.IgnoreObjectArgument = false; 3347 Candidate.FinalConversion.setAsIdentityConversion(); 3348 Candidate.FinalConversion.setFromType(ConvType); 3349 Candidate.FinalConversion.setAllToTypes(ToType); 3350 3351 // Determine the implicit conversion sequence for the implicit 3352 // object parameter. 3353 Candidate.Viable = true; 3354 Candidate.Conversions.resize(1); 3355 Candidate.Conversions[0] 3356 = TryObjectArgumentInitialization(From->getType(), Conversion, 3357 ActingContext); 3358 // Conversion functions to a different type in the base class is visible in 3359 // the derived class. So, a derived to base conversion should not participate 3360 // in overload resolution. 3361 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 3362 Candidate.Conversions[0].Standard.Second = ICK_Identity; 3363 if (Candidate.Conversions[0].isBad()) { 3364 Candidate.Viable = false; 3365 Candidate.FailureKind = ovl_fail_bad_conversion; 3366 return; 3367 } 3368 3369 // We won't go through a user-define type conversion function to convert a 3370 // derived to base as such conversions are given Conversion Rank. They only 3371 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 3372 QualType FromCanon 3373 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 3374 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 3375 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 3376 Candidate.Viable = false; 3377 Candidate.FailureKind = ovl_fail_trivial_conversion; 3378 return; 3379 } 3380 3381 // To determine what the conversion from the result of calling the 3382 // conversion function to the type we're eventually trying to 3383 // convert to (ToType), we need to synthesize a call to the 3384 // conversion function and attempt copy initialization from it. This 3385 // makes sure that we get the right semantics with respect to 3386 // lvalues/rvalues and the type. Fortunately, we can allocate this 3387 // call on the stack and we don't need its arguments to be 3388 // well-formed. 3389 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 3390 From->getLocStart()); 3391 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 3392 CastExpr::CK_FunctionToPointerDecay, 3393 &ConversionRef, CXXBaseSpecifierArray(), false); 3394 3395 // Note that it is safe to allocate CallExpr on the stack here because 3396 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 3397 // allocator). 3398 CallExpr Call(Context, &ConversionFn, 0, 0, 3399 Conversion->getConversionType().getNonReferenceType(), 3400 From->getLocStart()); 3401 ImplicitConversionSequence ICS = 3402 TryCopyInitialization(*this, &Call, ToType, 3403 /*SuppressUserConversions=*/true, 3404 /*InOverloadResolution=*/false); 3405 3406 switch (ICS.getKind()) { 3407 case ImplicitConversionSequence::StandardConversion: 3408 Candidate.FinalConversion = ICS.Standard; 3409 3410 // C++ [over.ics.user]p3: 3411 // If the user-defined conversion is specified by a specialization of a 3412 // conversion function template, the second standard conversion sequence 3413 // shall have exact match rank. 3414 if (Conversion->getPrimaryTemplate() && 3415 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { 3416 Candidate.Viable = false; 3417 Candidate.FailureKind = ovl_fail_final_conversion_not_exact; 3418 } 3419 3420 break; 3421 3422 case ImplicitConversionSequence::BadConversion: 3423 Candidate.Viable = false; 3424 Candidate.FailureKind = ovl_fail_bad_final_conversion; 3425 break; 3426 3427 default: 3428 assert(false && 3429 "Can only end up with a standard conversion sequence or failure"); 3430 } 3431} 3432 3433/// \brief Adds a conversion function template specialization 3434/// candidate to the overload set, using template argument deduction 3435/// to deduce the template arguments of the conversion function 3436/// template from the type that we are converting to (C++ 3437/// [temp.deduct.conv]). 3438void 3439Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 3440 DeclAccessPair FoundDecl, 3441 CXXRecordDecl *ActingDC, 3442 Expr *From, QualType ToType, 3443 OverloadCandidateSet &CandidateSet) { 3444 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 3445 "Only conversion function templates permitted here"); 3446 3447 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3448 return; 3449 3450 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3451 CXXConversionDecl *Specialization = 0; 3452 if (TemplateDeductionResult Result 3453 = DeduceTemplateArguments(FunctionTemplate, ToType, 3454 Specialization, Info)) { 3455 CandidateSet.push_back(OverloadCandidate()); 3456 OverloadCandidate &Candidate = CandidateSet.back(); 3457 Candidate.FoundDecl = FoundDecl; 3458 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3459 Candidate.Viable = false; 3460 Candidate.FailureKind = ovl_fail_bad_deduction; 3461 Candidate.IsSurrogate = false; 3462 Candidate.IgnoreObjectArgument = false; 3463 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3464 Info); 3465 return; 3466 } 3467 3468 // Add the conversion function template specialization produced by 3469 // template argument deduction as a candidate. 3470 assert(Specialization && "Missing function template specialization?"); 3471 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, 3472 CandidateSet); 3473} 3474 3475/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 3476/// converts the given @c Object to a function pointer via the 3477/// conversion function @c Conversion, and then attempts to call it 3478/// with the given arguments (C++ [over.call.object]p2-4). Proto is 3479/// the type of function that we'll eventually be calling. 3480void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 3481 DeclAccessPair FoundDecl, 3482 CXXRecordDecl *ActingContext, 3483 const FunctionProtoType *Proto, 3484 QualType ObjectType, 3485 Expr **Args, unsigned NumArgs, 3486 OverloadCandidateSet& CandidateSet) { 3487 if (!CandidateSet.isNewCandidate(Conversion)) 3488 return; 3489 3490 // Overload resolution is always an unevaluated context. 3491 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3492 3493 CandidateSet.push_back(OverloadCandidate()); 3494 OverloadCandidate& Candidate = CandidateSet.back(); 3495 Candidate.FoundDecl = FoundDecl; 3496 Candidate.Function = 0; 3497 Candidate.Surrogate = Conversion; 3498 Candidate.Viable = true; 3499 Candidate.IsSurrogate = true; 3500 Candidate.IgnoreObjectArgument = false; 3501 Candidate.Conversions.resize(NumArgs + 1); 3502 3503 // Determine the implicit conversion sequence for the implicit 3504 // object parameter. 3505 ImplicitConversionSequence ObjectInit 3506 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 3507 if (ObjectInit.isBad()) { 3508 Candidate.Viable = false; 3509 Candidate.FailureKind = ovl_fail_bad_conversion; 3510 Candidate.Conversions[0] = ObjectInit; 3511 return; 3512 } 3513 3514 // The first conversion is actually a user-defined conversion whose 3515 // first conversion is ObjectInit's standard conversion (which is 3516 // effectively a reference binding). Record it as such. 3517 Candidate.Conversions[0].setUserDefined(); 3518 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 3519 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 3520 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 3521 Candidate.Conversions[0].UserDefined.After 3522 = Candidate.Conversions[0].UserDefined.Before; 3523 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 3524 3525 // Find the 3526 unsigned NumArgsInProto = Proto->getNumArgs(); 3527 3528 // (C++ 13.3.2p2): A candidate function having fewer than m 3529 // parameters is viable only if it has an ellipsis in its parameter 3530 // list (8.3.5). 3531 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3532 Candidate.Viable = false; 3533 Candidate.FailureKind = ovl_fail_too_many_arguments; 3534 return; 3535 } 3536 3537 // Function types don't have any default arguments, so just check if 3538 // we have enough arguments. 3539 if (NumArgs < NumArgsInProto) { 3540 // Not enough arguments. 3541 Candidate.Viable = false; 3542 Candidate.FailureKind = ovl_fail_too_few_arguments; 3543 return; 3544 } 3545 3546 // Determine the implicit conversion sequences for each of the 3547 // arguments. 3548 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3549 if (ArgIdx < NumArgsInProto) { 3550 // (C++ 13.3.2p3): for F to be a viable function, there shall 3551 // exist for each argument an implicit conversion sequence 3552 // (13.3.3.1) that converts that argument to the corresponding 3553 // parameter of F. 3554 QualType ParamType = Proto->getArgType(ArgIdx); 3555 Candidate.Conversions[ArgIdx + 1] 3556 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3557 /*SuppressUserConversions=*/false, 3558 /*InOverloadResolution=*/false); 3559 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3560 Candidate.Viable = false; 3561 Candidate.FailureKind = ovl_fail_bad_conversion; 3562 break; 3563 } 3564 } else { 3565 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3566 // argument for which there is no corresponding parameter is 3567 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3568 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3569 } 3570 } 3571} 3572 3573/// \brief Add overload candidates for overloaded operators that are 3574/// member functions. 3575/// 3576/// Add the overloaded operator candidates that are member functions 3577/// for the operator Op that was used in an operator expression such 3578/// as "x Op y". , Args/NumArgs provides the operator arguments, and 3579/// CandidateSet will store the added overload candidates. (C++ 3580/// [over.match.oper]). 3581void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 3582 SourceLocation OpLoc, 3583 Expr **Args, unsigned NumArgs, 3584 OverloadCandidateSet& CandidateSet, 3585 SourceRange OpRange) { 3586 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3587 3588 // C++ [over.match.oper]p3: 3589 // For a unary operator @ with an operand of a type whose 3590 // cv-unqualified version is T1, and for a binary operator @ with 3591 // a left operand of a type whose cv-unqualified version is T1 and 3592 // a right operand of a type whose cv-unqualified version is T2, 3593 // three sets of candidate functions, designated member 3594 // candidates, non-member candidates and built-in candidates, are 3595 // constructed as follows: 3596 QualType T1 = Args[0]->getType(); 3597 QualType T2; 3598 if (NumArgs > 1) 3599 T2 = Args[1]->getType(); 3600 3601 // -- If T1 is a class type, the set of member candidates is the 3602 // result of the qualified lookup of T1::operator@ 3603 // (13.3.1.1.1); otherwise, the set of member candidates is 3604 // empty. 3605 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 3606 // Complete the type if it can be completed. Otherwise, we're done. 3607 if (RequireCompleteType(OpLoc, T1, PDiag())) 3608 return; 3609 3610 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 3611 LookupQualifiedName(Operators, T1Rec->getDecl()); 3612 Operators.suppressDiagnostics(); 3613 3614 for (LookupResult::iterator Oper = Operators.begin(), 3615 OperEnd = Operators.end(); 3616 Oper != OperEnd; 3617 ++Oper) 3618 AddMethodCandidate(Oper.getPair(), Args[0]->getType(), 3619 Args + 1, NumArgs - 1, CandidateSet, 3620 /* SuppressUserConversions = */ false); 3621 } 3622} 3623 3624/// AddBuiltinCandidate - Add a candidate for a built-in 3625/// operator. ResultTy and ParamTys are the result and parameter types 3626/// of the built-in candidate, respectively. Args and NumArgs are the 3627/// arguments being passed to the candidate. IsAssignmentOperator 3628/// should be true when this built-in candidate is an assignment 3629/// operator. NumContextualBoolArguments is the number of arguments 3630/// (at the beginning of the argument list) that will be contextually 3631/// converted to bool. 3632void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3633 Expr **Args, unsigned NumArgs, 3634 OverloadCandidateSet& CandidateSet, 3635 bool IsAssignmentOperator, 3636 unsigned NumContextualBoolArguments) { 3637 // Overload resolution is always an unevaluated context. 3638 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3639 3640 // Add this candidate 3641 CandidateSet.push_back(OverloadCandidate()); 3642 OverloadCandidate& Candidate = CandidateSet.back(); 3643 Candidate.FoundDecl = DeclAccessPair::make(0, AS_none); 3644 Candidate.Function = 0; 3645 Candidate.IsSurrogate = false; 3646 Candidate.IgnoreObjectArgument = false; 3647 Candidate.BuiltinTypes.ResultTy = ResultTy; 3648 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3649 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3650 3651 // Determine the implicit conversion sequences for each of the 3652 // arguments. 3653 Candidate.Viable = true; 3654 Candidate.Conversions.resize(NumArgs); 3655 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3656 // C++ [over.match.oper]p4: 3657 // For the built-in assignment operators, conversions of the 3658 // left operand are restricted as follows: 3659 // -- no temporaries are introduced to hold the left operand, and 3660 // -- no user-defined conversions are applied to the left 3661 // operand to achieve a type match with the left-most 3662 // parameter of a built-in candidate. 3663 // 3664 // We block these conversions by turning off user-defined 3665 // conversions, since that is the only way that initialization of 3666 // a reference to a non-class type can occur from something that 3667 // is not of the same type. 3668 if (ArgIdx < NumContextualBoolArguments) { 3669 assert(ParamTys[ArgIdx] == Context.BoolTy && 3670 "Contextual conversion to bool requires bool type"); 3671 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3672 } else { 3673 Candidate.Conversions[ArgIdx] 3674 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], 3675 ArgIdx == 0 && IsAssignmentOperator, 3676 /*InOverloadResolution=*/false); 3677 } 3678 if (Candidate.Conversions[ArgIdx].isBad()) { 3679 Candidate.Viable = false; 3680 Candidate.FailureKind = ovl_fail_bad_conversion; 3681 break; 3682 } 3683 } 3684} 3685 3686/// BuiltinCandidateTypeSet - A set of types that will be used for the 3687/// candidate operator functions for built-in operators (C++ 3688/// [over.built]). The types are separated into pointer types and 3689/// enumeration types. 3690class BuiltinCandidateTypeSet { 3691 /// TypeSet - A set of types. 3692 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3693 3694 /// PointerTypes - The set of pointer types that will be used in the 3695 /// built-in candidates. 3696 TypeSet PointerTypes; 3697 3698 /// MemberPointerTypes - The set of member pointer types that will be 3699 /// used in the built-in candidates. 3700 TypeSet MemberPointerTypes; 3701 3702 /// EnumerationTypes - The set of enumeration types that will be 3703 /// used in the built-in candidates. 3704 TypeSet EnumerationTypes; 3705 3706 /// Sema - The semantic analysis instance where we are building the 3707 /// candidate type set. 3708 Sema &SemaRef; 3709 3710 /// Context - The AST context in which we will build the type sets. 3711 ASTContext &Context; 3712 3713 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3714 const Qualifiers &VisibleQuals); 3715 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3716 3717public: 3718 /// iterator - Iterates through the types that are part of the set. 3719 typedef TypeSet::iterator iterator; 3720 3721 BuiltinCandidateTypeSet(Sema &SemaRef) 3722 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3723 3724 void AddTypesConvertedFrom(QualType Ty, 3725 SourceLocation Loc, 3726 bool AllowUserConversions, 3727 bool AllowExplicitConversions, 3728 const Qualifiers &VisibleTypeConversionsQuals); 3729 3730 /// pointer_begin - First pointer type found; 3731 iterator pointer_begin() { return PointerTypes.begin(); } 3732 3733 /// pointer_end - Past the last pointer type found; 3734 iterator pointer_end() { return PointerTypes.end(); } 3735 3736 /// member_pointer_begin - First member pointer type found; 3737 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3738 3739 /// member_pointer_end - Past the last member pointer type found; 3740 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3741 3742 /// enumeration_begin - First enumeration type found; 3743 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3744 3745 /// enumeration_end - Past the last enumeration type found; 3746 iterator enumeration_end() { return EnumerationTypes.end(); } 3747}; 3748 3749/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3750/// the set of pointer types along with any more-qualified variants of 3751/// that type. For example, if @p Ty is "int const *", this routine 3752/// will add "int const *", "int const volatile *", "int const 3753/// restrict *", and "int const volatile restrict *" to the set of 3754/// pointer types. Returns true if the add of @p Ty itself succeeded, 3755/// false otherwise. 3756/// 3757/// FIXME: what to do about extended qualifiers? 3758bool 3759BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3760 const Qualifiers &VisibleQuals) { 3761 3762 // Insert this type. 3763 if (!PointerTypes.insert(Ty)) 3764 return false; 3765 3766 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3767 assert(PointerTy && "type was not a pointer type!"); 3768 3769 QualType PointeeTy = PointerTy->getPointeeType(); 3770 // Don't add qualified variants of arrays. For one, they're not allowed 3771 // (the qualifier would sink to the element type), and for another, the 3772 // only overload situation where it matters is subscript or pointer +- int, 3773 // and those shouldn't have qualifier variants anyway. 3774 if (PointeeTy->isArrayType()) 3775 return true; 3776 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3777 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3778 BaseCVR = Array->getElementType().getCVRQualifiers(); 3779 bool hasVolatile = VisibleQuals.hasVolatile(); 3780 bool hasRestrict = VisibleQuals.hasRestrict(); 3781 3782 // Iterate through all strict supersets of BaseCVR. 3783 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3784 if ((CVR | BaseCVR) != CVR) continue; 3785 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3786 // in the types. 3787 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3788 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3789 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3790 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3791 } 3792 3793 return true; 3794} 3795 3796/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3797/// to the set of pointer types along with any more-qualified variants of 3798/// that type. For example, if @p Ty is "int const *", this routine 3799/// will add "int const *", "int const volatile *", "int const 3800/// restrict *", and "int const volatile restrict *" to the set of 3801/// pointer types. Returns true if the add of @p Ty itself succeeded, 3802/// false otherwise. 3803/// 3804/// FIXME: what to do about extended qualifiers? 3805bool 3806BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3807 QualType Ty) { 3808 // Insert this type. 3809 if (!MemberPointerTypes.insert(Ty)) 3810 return false; 3811 3812 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3813 assert(PointerTy && "type was not a member pointer type!"); 3814 3815 QualType PointeeTy = PointerTy->getPointeeType(); 3816 // Don't add qualified variants of arrays. For one, they're not allowed 3817 // (the qualifier would sink to the element type), and for another, the 3818 // only overload situation where it matters is subscript or pointer +- int, 3819 // and those shouldn't have qualifier variants anyway. 3820 if (PointeeTy->isArrayType()) 3821 return true; 3822 const Type *ClassTy = PointerTy->getClass(); 3823 3824 // Iterate through all strict supersets of the pointee type's CVR 3825 // qualifiers. 3826 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3827 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3828 if ((CVR | BaseCVR) != CVR) continue; 3829 3830 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3831 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3832 } 3833 3834 return true; 3835} 3836 3837/// AddTypesConvertedFrom - Add each of the types to which the type @p 3838/// Ty can be implicit converted to the given set of @p Types. We're 3839/// primarily interested in pointer types and enumeration types. We also 3840/// take member pointer types, for the conditional operator. 3841/// AllowUserConversions is true if we should look at the conversion 3842/// functions of a class type, and AllowExplicitConversions if we 3843/// should also include the explicit conversion functions of a class 3844/// type. 3845void 3846BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3847 SourceLocation Loc, 3848 bool AllowUserConversions, 3849 bool AllowExplicitConversions, 3850 const Qualifiers &VisibleQuals) { 3851 // Only deal with canonical types. 3852 Ty = Context.getCanonicalType(Ty); 3853 3854 // Look through reference types; they aren't part of the type of an 3855 // expression for the purposes of conversions. 3856 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3857 Ty = RefTy->getPointeeType(); 3858 3859 // We don't care about qualifiers on the type. 3860 Ty = Ty.getLocalUnqualifiedType(); 3861 3862 // If we're dealing with an array type, decay to the pointer. 3863 if (Ty->isArrayType()) 3864 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3865 3866 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3867 QualType PointeeTy = PointerTy->getPointeeType(); 3868 3869 // Insert our type, and its more-qualified variants, into the set 3870 // of types. 3871 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3872 return; 3873 } else if (Ty->isMemberPointerType()) { 3874 // Member pointers are far easier, since the pointee can't be converted. 3875 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3876 return; 3877 } else if (Ty->isEnumeralType()) { 3878 EnumerationTypes.insert(Ty); 3879 } else if (AllowUserConversions) { 3880 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3881 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3882 // No conversion functions in incomplete types. 3883 return; 3884 } 3885 3886 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3887 const UnresolvedSetImpl *Conversions 3888 = ClassDecl->getVisibleConversionFunctions(); 3889 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3890 E = Conversions->end(); I != E; ++I) { 3891 NamedDecl *D = I.getDecl(); 3892 if (isa<UsingShadowDecl>(D)) 3893 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3894 3895 // Skip conversion function templates; they don't tell us anything 3896 // about which builtin types we can convert to. 3897 if (isa<FunctionTemplateDecl>(D)) 3898 continue; 3899 3900 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 3901 if (AllowExplicitConversions || !Conv->isExplicit()) { 3902 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3903 VisibleQuals); 3904 } 3905 } 3906 } 3907 } 3908} 3909 3910/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3911/// the volatile- and non-volatile-qualified assignment operators for the 3912/// given type to the candidate set. 3913static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3914 QualType T, 3915 Expr **Args, 3916 unsigned NumArgs, 3917 OverloadCandidateSet &CandidateSet) { 3918 QualType ParamTypes[2]; 3919 3920 // T& operator=(T&, T) 3921 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3922 ParamTypes[1] = T; 3923 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3924 /*IsAssignmentOperator=*/true); 3925 3926 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3927 // volatile T& operator=(volatile T&, T) 3928 ParamTypes[0] 3929 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3930 ParamTypes[1] = T; 3931 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3932 /*IsAssignmentOperator=*/true); 3933 } 3934} 3935 3936/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3937/// if any, found in visible type conversion functions found in ArgExpr's type. 3938static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3939 Qualifiers VRQuals; 3940 const RecordType *TyRec; 3941 if (const MemberPointerType *RHSMPType = 3942 ArgExpr->getType()->getAs<MemberPointerType>()) 3943 TyRec = RHSMPType->getClass()->getAs<RecordType>(); 3944 else 3945 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3946 if (!TyRec) { 3947 // Just to be safe, assume the worst case. 3948 VRQuals.addVolatile(); 3949 VRQuals.addRestrict(); 3950 return VRQuals; 3951 } 3952 3953 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3954 if (!ClassDecl->hasDefinition()) 3955 return VRQuals; 3956 3957 const UnresolvedSetImpl *Conversions = 3958 ClassDecl->getVisibleConversionFunctions(); 3959 3960 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3961 E = Conversions->end(); I != E; ++I) { 3962 NamedDecl *D = I.getDecl(); 3963 if (isa<UsingShadowDecl>(D)) 3964 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3965 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { 3966 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3967 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3968 CanTy = ResTypeRef->getPointeeType(); 3969 // Need to go down the pointer/mempointer chain and add qualifiers 3970 // as see them. 3971 bool done = false; 3972 while (!done) { 3973 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3974 CanTy = ResTypePtr->getPointeeType(); 3975 else if (const MemberPointerType *ResTypeMPtr = 3976 CanTy->getAs<MemberPointerType>()) 3977 CanTy = ResTypeMPtr->getPointeeType(); 3978 else 3979 done = true; 3980 if (CanTy.isVolatileQualified()) 3981 VRQuals.addVolatile(); 3982 if (CanTy.isRestrictQualified()) 3983 VRQuals.addRestrict(); 3984 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3985 return VRQuals; 3986 } 3987 } 3988 } 3989 return VRQuals; 3990} 3991 3992/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3993/// operator overloads to the candidate set (C++ [over.built]), based 3994/// on the operator @p Op and the arguments given. For example, if the 3995/// operator is a binary '+', this routine might add "int 3996/// operator+(int, int)" to cover integer addition. 3997void 3998Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3999 SourceLocation OpLoc, 4000 Expr **Args, unsigned NumArgs, 4001 OverloadCandidateSet& CandidateSet) { 4002 // The set of "promoted arithmetic types", which are the arithmetic 4003 // types are that preserved by promotion (C++ [over.built]p2). Note 4004 // that the first few of these types are the promoted integral 4005 // types; these types need to be first. 4006 // FIXME: What about complex? 4007 const unsigned FirstIntegralType = 0; 4008 const unsigned LastIntegralType = 13; 4009 const unsigned FirstPromotedIntegralType = 7, 4010 LastPromotedIntegralType = 13; 4011 const unsigned FirstPromotedArithmeticType = 7, 4012 LastPromotedArithmeticType = 16; 4013 const unsigned NumArithmeticTypes = 16; 4014 QualType ArithmeticTypes[NumArithmeticTypes] = { 4015 Context.BoolTy, Context.CharTy, Context.WCharTy, 4016// FIXME: Context.Char16Ty, Context.Char32Ty, 4017 Context.SignedCharTy, Context.ShortTy, 4018 Context.UnsignedCharTy, Context.UnsignedShortTy, 4019 Context.IntTy, Context.LongTy, Context.LongLongTy, 4020 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 4021 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 4022 }; 4023 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 4024 "Invalid first promoted integral type"); 4025 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 4026 == Context.UnsignedLongLongTy && 4027 "Invalid last promoted integral type"); 4028 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 4029 "Invalid first promoted arithmetic type"); 4030 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 4031 == Context.LongDoubleTy && 4032 "Invalid last promoted arithmetic type"); 4033 4034 // Find all of the types that the arguments can convert to, but only 4035 // if the operator we're looking at has built-in operator candidates 4036 // that make use of these types. 4037 Qualifiers VisibleTypeConversionsQuals; 4038 VisibleTypeConversionsQuals.addConst(); 4039 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4040 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 4041 4042 BuiltinCandidateTypeSet CandidateTypes(*this); 4043 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 4044 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 4045 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 4046 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 4047 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 4048 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 4049 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4050 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 4051 OpLoc, 4052 true, 4053 (Op == OO_Exclaim || 4054 Op == OO_AmpAmp || 4055 Op == OO_PipePipe), 4056 VisibleTypeConversionsQuals); 4057 } 4058 4059 bool isComparison = false; 4060 switch (Op) { 4061 case OO_None: 4062 case NUM_OVERLOADED_OPERATORS: 4063 assert(false && "Expected an overloaded operator"); 4064 break; 4065 4066 case OO_Star: // '*' is either unary or binary 4067 if (NumArgs == 1) 4068 goto UnaryStar; 4069 else 4070 goto BinaryStar; 4071 break; 4072 4073 case OO_Plus: // '+' is either unary or binary 4074 if (NumArgs == 1) 4075 goto UnaryPlus; 4076 else 4077 goto BinaryPlus; 4078 break; 4079 4080 case OO_Minus: // '-' is either unary or binary 4081 if (NumArgs == 1) 4082 goto UnaryMinus; 4083 else 4084 goto BinaryMinus; 4085 break; 4086 4087 case OO_Amp: // '&' is either unary or binary 4088 if (NumArgs == 1) 4089 goto UnaryAmp; 4090 else 4091 goto BinaryAmp; 4092 4093 case OO_PlusPlus: 4094 case OO_MinusMinus: 4095 // C++ [over.built]p3: 4096 // 4097 // For every pair (T, VQ), where T is an arithmetic type, and VQ 4098 // is either volatile or empty, there exist candidate operator 4099 // functions of the form 4100 // 4101 // VQ T& operator++(VQ T&); 4102 // T operator++(VQ T&, int); 4103 // 4104 // C++ [over.built]p4: 4105 // 4106 // For every pair (T, VQ), where T is an arithmetic type other 4107 // than bool, and VQ is either volatile or empty, there exist 4108 // candidate operator functions of the form 4109 // 4110 // VQ T& operator--(VQ T&); 4111 // T operator--(VQ T&, int); 4112 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 4113 Arith < NumArithmeticTypes; ++Arith) { 4114 QualType ArithTy = ArithmeticTypes[Arith]; 4115 QualType ParamTypes[2] 4116 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 4117 4118 // Non-volatile version. 4119 if (NumArgs == 1) 4120 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4121 else 4122 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 4123 // heuristic to reduce number of builtin candidates in the set. 4124 // Add volatile version only if there are conversions to a volatile type. 4125 if (VisibleTypeConversionsQuals.hasVolatile()) { 4126 // Volatile version 4127 ParamTypes[0] 4128 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 4129 if (NumArgs == 1) 4130 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4131 else 4132 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 4133 } 4134 } 4135 4136 // C++ [over.built]p5: 4137 // 4138 // For every pair (T, VQ), where T is a cv-qualified or 4139 // cv-unqualified object type, and VQ is either volatile or 4140 // empty, there exist candidate operator functions of the form 4141 // 4142 // T*VQ& operator++(T*VQ&); 4143 // T*VQ& operator--(T*VQ&); 4144 // T* operator++(T*VQ&, int); 4145 // T* operator--(T*VQ&, int); 4146 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4147 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4148 // Skip pointer types that aren't pointers to object types. 4149 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 4150 continue; 4151 4152 QualType ParamTypes[2] = { 4153 Context.getLValueReferenceType(*Ptr), Context.IntTy 4154 }; 4155 4156 // Without volatile 4157 if (NumArgs == 1) 4158 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4159 else 4160 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4161 4162 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4163 VisibleTypeConversionsQuals.hasVolatile()) { 4164 // With volatile 4165 ParamTypes[0] 4166 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4167 if (NumArgs == 1) 4168 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4169 else 4170 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4171 } 4172 } 4173 break; 4174 4175 UnaryStar: 4176 // C++ [over.built]p6: 4177 // For every cv-qualified or cv-unqualified object type T, there 4178 // exist candidate operator functions of the form 4179 // 4180 // T& operator*(T*); 4181 // 4182 // C++ [over.built]p7: 4183 // For every function type T, there exist candidate operator 4184 // functions of the form 4185 // T& operator*(T*); 4186 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4187 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4188 QualType ParamTy = *Ptr; 4189 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 4190 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 4191 &ParamTy, Args, 1, CandidateSet); 4192 } 4193 break; 4194 4195 UnaryPlus: 4196 // C++ [over.built]p8: 4197 // For every type T, there exist candidate operator functions of 4198 // the form 4199 // 4200 // T* operator+(T*); 4201 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4202 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4203 QualType ParamTy = *Ptr; 4204 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 4205 } 4206 4207 // Fall through 4208 4209 UnaryMinus: 4210 // C++ [over.built]p9: 4211 // For every promoted arithmetic type T, there exist candidate 4212 // operator functions of the form 4213 // 4214 // T operator+(T); 4215 // T operator-(T); 4216 for (unsigned Arith = FirstPromotedArithmeticType; 4217 Arith < LastPromotedArithmeticType; ++Arith) { 4218 QualType ArithTy = ArithmeticTypes[Arith]; 4219 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 4220 } 4221 break; 4222 4223 case OO_Tilde: 4224 // C++ [over.built]p10: 4225 // For every promoted integral type T, there exist candidate 4226 // operator functions of the form 4227 // 4228 // T operator~(T); 4229 for (unsigned Int = FirstPromotedIntegralType; 4230 Int < LastPromotedIntegralType; ++Int) { 4231 QualType IntTy = ArithmeticTypes[Int]; 4232 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 4233 } 4234 break; 4235 4236 case OO_New: 4237 case OO_Delete: 4238 case OO_Array_New: 4239 case OO_Array_Delete: 4240 case OO_Call: 4241 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 4242 break; 4243 4244 case OO_Comma: 4245 UnaryAmp: 4246 case OO_Arrow: 4247 // C++ [over.match.oper]p3: 4248 // -- For the operator ',', the unary operator '&', or the 4249 // operator '->', the built-in candidates set is empty. 4250 break; 4251 4252 case OO_EqualEqual: 4253 case OO_ExclaimEqual: 4254 // C++ [over.match.oper]p16: 4255 // For every pointer to member type T, there exist candidate operator 4256 // functions of the form 4257 // 4258 // bool operator==(T,T); 4259 // bool operator!=(T,T); 4260 for (BuiltinCandidateTypeSet::iterator 4261 MemPtr = CandidateTypes.member_pointer_begin(), 4262 MemPtrEnd = CandidateTypes.member_pointer_end(); 4263 MemPtr != MemPtrEnd; 4264 ++MemPtr) { 4265 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 4266 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4267 } 4268 4269 // Fall through 4270 4271 case OO_Less: 4272 case OO_Greater: 4273 case OO_LessEqual: 4274 case OO_GreaterEqual: 4275 // C++ [over.built]p15: 4276 // 4277 // For every pointer or enumeration type T, there exist 4278 // candidate operator functions of the form 4279 // 4280 // bool operator<(T, T); 4281 // bool operator>(T, T); 4282 // bool operator<=(T, T); 4283 // bool operator>=(T, T); 4284 // bool operator==(T, T); 4285 // bool operator!=(T, T); 4286 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4287 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4288 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4289 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4290 } 4291 for (BuiltinCandidateTypeSet::iterator Enum 4292 = CandidateTypes.enumeration_begin(); 4293 Enum != CandidateTypes.enumeration_end(); ++Enum) { 4294 QualType ParamTypes[2] = { *Enum, *Enum }; 4295 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4296 } 4297 4298 // Fall through. 4299 isComparison = true; 4300 4301 BinaryPlus: 4302 BinaryMinus: 4303 if (!isComparison) { 4304 // We didn't fall through, so we must have OO_Plus or OO_Minus. 4305 4306 // C++ [over.built]p13: 4307 // 4308 // For every cv-qualified or cv-unqualified object type T 4309 // there exist candidate operator functions of the form 4310 // 4311 // T* operator+(T*, ptrdiff_t); 4312 // T& operator[](T*, ptrdiff_t); [BELOW] 4313 // T* operator-(T*, ptrdiff_t); 4314 // T* operator+(ptrdiff_t, T*); 4315 // T& operator[](ptrdiff_t, T*); [BELOW] 4316 // 4317 // C++ [over.built]p14: 4318 // 4319 // For every T, where T is a pointer to object type, there 4320 // exist candidate operator functions of the form 4321 // 4322 // ptrdiff_t operator-(T, T); 4323 for (BuiltinCandidateTypeSet::iterator Ptr 4324 = CandidateTypes.pointer_begin(); 4325 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4326 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4327 4328 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 4329 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4330 4331 if (Op == OO_Plus) { 4332 // T* operator+(ptrdiff_t, T*); 4333 ParamTypes[0] = ParamTypes[1]; 4334 ParamTypes[1] = *Ptr; 4335 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4336 } else { 4337 // ptrdiff_t operator-(T, T); 4338 ParamTypes[1] = *Ptr; 4339 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 4340 Args, 2, CandidateSet); 4341 } 4342 } 4343 } 4344 // Fall through 4345 4346 case OO_Slash: 4347 BinaryStar: 4348 Conditional: 4349 // C++ [over.built]p12: 4350 // 4351 // For every pair of promoted arithmetic types L and R, there 4352 // exist candidate operator functions of the form 4353 // 4354 // LR operator*(L, R); 4355 // LR operator/(L, R); 4356 // LR operator+(L, R); 4357 // LR operator-(L, R); 4358 // bool operator<(L, R); 4359 // bool operator>(L, R); 4360 // bool operator<=(L, R); 4361 // bool operator>=(L, R); 4362 // bool operator==(L, R); 4363 // bool operator!=(L, R); 4364 // 4365 // where LR is the result of the usual arithmetic conversions 4366 // between types L and R. 4367 // 4368 // C++ [over.built]p24: 4369 // 4370 // For every pair of promoted arithmetic types L and R, there exist 4371 // candidate operator functions of the form 4372 // 4373 // LR operator?(bool, L, R); 4374 // 4375 // where LR is the result of the usual arithmetic conversions 4376 // between types L and R. 4377 // Our candidates ignore the first parameter. 4378 for (unsigned Left = FirstPromotedArithmeticType; 4379 Left < LastPromotedArithmeticType; ++Left) { 4380 for (unsigned Right = FirstPromotedArithmeticType; 4381 Right < LastPromotedArithmeticType; ++Right) { 4382 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4383 QualType Result 4384 = isComparison 4385 ? Context.BoolTy 4386 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4387 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4388 } 4389 } 4390 break; 4391 4392 case OO_Percent: 4393 BinaryAmp: 4394 case OO_Caret: 4395 case OO_Pipe: 4396 case OO_LessLess: 4397 case OO_GreaterGreater: 4398 // C++ [over.built]p17: 4399 // 4400 // For every pair of promoted integral types L and R, there 4401 // exist candidate operator functions of the form 4402 // 4403 // LR operator%(L, R); 4404 // LR operator&(L, R); 4405 // LR operator^(L, R); 4406 // LR operator|(L, R); 4407 // L operator<<(L, R); 4408 // L operator>>(L, R); 4409 // 4410 // where LR is the result of the usual arithmetic conversions 4411 // between types L and R. 4412 for (unsigned Left = FirstPromotedIntegralType; 4413 Left < LastPromotedIntegralType; ++Left) { 4414 for (unsigned Right = FirstPromotedIntegralType; 4415 Right < LastPromotedIntegralType; ++Right) { 4416 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4417 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 4418 ? LandR[0] 4419 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4420 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4421 } 4422 } 4423 break; 4424 4425 case OO_Equal: 4426 // C++ [over.built]p20: 4427 // 4428 // For every pair (T, VQ), where T is an enumeration or 4429 // pointer to member type and VQ is either volatile or 4430 // empty, there exist candidate operator functions of the form 4431 // 4432 // VQ T& operator=(VQ T&, T); 4433 for (BuiltinCandidateTypeSet::iterator 4434 Enum = CandidateTypes.enumeration_begin(), 4435 EnumEnd = CandidateTypes.enumeration_end(); 4436 Enum != EnumEnd; ++Enum) 4437 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 4438 CandidateSet); 4439 for (BuiltinCandidateTypeSet::iterator 4440 MemPtr = CandidateTypes.member_pointer_begin(), 4441 MemPtrEnd = CandidateTypes.member_pointer_end(); 4442 MemPtr != MemPtrEnd; ++MemPtr) 4443 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 4444 CandidateSet); 4445 // Fall through. 4446 4447 case OO_PlusEqual: 4448 case OO_MinusEqual: 4449 // C++ [over.built]p19: 4450 // 4451 // For every pair (T, VQ), where T is any type and VQ is either 4452 // volatile or empty, there exist candidate operator functions 4453 // of the form 4454 // 4455 // T*VQ& operator=(T*VQ&, T*); 4456 // 4457 // C++ [over.built]p21: 4458 // 4459 // For every pair (T, VQ), where T is a cv-qualified or 4460 // cv-unqualified object type and VQ is either volatile or 4461 // empty, there exist candidate operator functions of the form 4462 // 4463 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 4464 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 4465 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4466 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4467 QualType ParamTypes[2]; 4468 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 4469 4470 // non-volatile version 4471 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 4472 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4473 /*IsAssigmentOperator=*/Op == OO_Equal); 4474 4475 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4476 VisibleTypeConversionsQuals.hasVolatile()) { 4477 // volatile version 4478 ParamTypes[0] 4479 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4480 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4481 /*IsAssigmentOperator=*/Op == OO_Equal); 4482 } 4483 } 4484 // Fall through. 4485 4486 case OO_StarEqual: 4487 case OO_SlashEqual: 4488 // C++ [over.built]p18: 4489 // 4490 // For every triple (L, VQ, R), where L is an arithmetic type, 4491 // VQ is either volatile or empty, and R is a promoted 4492 // arithmetic type, there exist candidate operator functions of 4493 // the form 4494 // 4495 // VQ L& operator=(VQ L&, R); 4496 // VQ L& operator*=(VQ L&, R); 4497 // VQ L& operator/=(VQ L&, R); 4498 // VQ L& operator+=(VQ L&, R); 4499 // VQ L& operator-=(VQ L&, R); 4500 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 4501 for (unsigned Right = FirstPromotedArithmeticType; 4502 Right < LastPromotedArithmeticType; ++Right) { 4503 QualType ParamTypes[2]; 4504 ParamTypes[1] = ArithmeticTypes[Right]; 4505 4506 // Add this built-in operator as a candidate (VQ is empty). 4507 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4508 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4509 /*IsAssigmentOperator=*/Op == OO_Equal); 4510 4511 // Add this built-in operator as a candidate (VQ is 'volatile'). 4512 if (VisibleTypeConversionsQuals.hasVolatile()) { 4513 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 4514 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4515 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4516 /*IsAssigmentOperator=*/Op == OO_Equal); 4517 } 4518 } 4519 } 4520 break; 4521 4522 case OO_PercentEqual: 4523 case OO_LessLessEqual: 4524 case OO_GreaterGreaterEqual: 4525 case OO_AmpEqual: 4526 case OO_CaretEqual: 4527 case OO_PipeEqual: 4528 // C++ [over.built]p22: 4529 // 4530 // For every triple (L, VQ, R), where L is an integral type, VQ 4531 // is either volatile or empty, and R is a promoted integral 4532 // type, there exist candidate operator functions of the form 4533 // 4534 // VQ L& operator%=(VQ L&, R); 4535 // VQ L& operator<<=(VQ L&, R); 4536 // VQ L& operator>>=(VQ L&, R); 4537 // VQ L& operator&=(VQ L&, R); 4538 // VQ L& operator^=(VQ L&, R); 4539 // VQ L& operator|=(VQ L&, R); 4540 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 4541 for (unsigned Right = FirstPromotedIntegralType; 4542 Right < LastPromotedIntegralType; ++Right) { 4543 QualType ParamTypes[2]; 4544 ParamTypes[1] = ArithmeticTypes[Right]; 4545 4546 // Add this built-in operator as a candidate (VQ is empty). 4547 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4548 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4549 if (VisibleTypeConversionsQuals.hasVolatile()) { 4550 // Add this built-in operator as a candidate (VQ is 'volatile'). 4551 ParamTypes[0] = ArithmeticTypes[Left]; 4552 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 4553 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4554 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4555 } 4556 } 4557 } 4558 break; 4559 4560 case OO_Exclaim: { 4561 // C++ [over.operator]p23: 4562 // 4563 // There also exist candidate operator functions of the form 4564 // 4565 // bool operator!(bool); 4566 // bool operator&&(bool, bool); [BELOW] 4567 // bool operator||(bool, bool); [BELOW] 4568 QualType ParamTy = Context.BoolTy; 4569 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 4570 /*IsAssignmentOperator=*/false, 4571 /*NumContextualBoolArguments=*/1); 4572 break; 4573 } 4574 4575 case OO_AmpAmp: 4576 case OO_PipePipe: { 4577 // C++ [over.operator]p23: 4578 // 4579 // There also exist candidate operator functions of the form 4580 // 4581 // bool operator!(bool); [ABOVE] 4582 // bool operator&&(bool, bool); 4583 // bool operator||(bool, bool); 4584 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 4585 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 4586 /*IsAssignmentOperator=*/false, 4587 /*NumContextualBoolArguments=*/2); 4588 break; 4589 } 4590 4591 case OO_Subscript: 4592 // C++ [over.built]p13: 4593 // 4594 // For every cv-qualified or cv-unqualified object type T there 4595 // exist candidate operator functions of the form 4596 // 4597 // T* operator+(T*, ptrdiff_t); [ABOVE] 4598 // T& operator[](T*, ptrdiff_t); 4599 // T* operator-(T*, ptrdiff_t); [ABOVE] 4600 // T* operator+(ptrdiff_t, T*); [ABOVE] 4601 // T& operator[](ptrdiff_t, T*); 4602 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4603 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4604 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4605 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 4606 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 4607 4608 // T& operator[](T*, ptrdiff_t) 4609 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4610 4611 // T& operator[](ptrdiff_t, T*); 4612 ParamTypes[0] = ParamTypes[1]; 4613 ParamTypes[1] = *Ptr; 4614 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4615 } 4616 break; 4617 4618 case OO_ArrowStar: 4619 // C++ [over.built]p11: 4620 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 4621 // C1 is the same type as C2 or is a derived class of C2, T is an object 4622 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 4623 // there exist candidate operator functions of the form 4624 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 4625 // where CV12 is the union of CV1 and CV2. 4626 { 4627 for (BuiltinCandidateTypeSet::iterator Ptr = 4628 CandidateTypes.pointer_begin(); 4629 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4630 QualType C1Ty = (*Ptr); 4631 QualType C1; 4632 QualifierCollector Q1; 4633 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 4634 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 4635 if (!isa<RecordType>(C1)) 4636 continue; 4637 // heuristic to reduce number of builtin candidates in the set. 4638 // Add volatile/restrict version only if there are conversions to a 4639 // volatile/restrict type. 4640 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 4641 continue; 4642 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4643 continue; 4644 } 4645 for (BuiltinCandidateTypeSet::iterator 4646 MemPtr = CandidateTypes.member_pointer_begin(), 4647 MemPtrEnd = CandidateTypes.member_pointer_end(); 4648 MemPtr != MemPtrEnd; ++MemPtr) { 4649 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4650 QualType C2 = QualType(mptr->getClass(), 0); 4651 C2 = C2.getUnqualifiedType(); 4652 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4653 break; 4654 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4655 // build CV12 T& 4656 QualType T = mptr->getPointeeType(); 4657 if (!VisibleTypeConversionsQuals.hasVolatile() && 4658 T.isVolatileQualified()) 4659 continue; 4660 if (!VisibleTypeConversionsQuals.hasRestrict() && 4661 T.isRestrictQualified()) 4662 continue; 4663 T = Q1.apply(T); 4664 QualType ResultTy = Context.getLValueReferenceType(T); 4665 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4666 } 4667 } 4668 } 4669 break; 4670 4671 case OO_Conditional: 4672 // Note that we don't consider the first argument, since it has been 4673 // contextually converted to bool long ago. The candidates below are 4674 // therefore added as binary. 4675 // 4676 // C++ [over.built]p24: 4677 // For every type T, where T is a pointer or pointer-to-member type, 4678 // there exist candidate operator functions of the form 4679 // 4680 // T operator?(bool, T, T); 4681 // 4682 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4683 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4684 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4685 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4686 } 4687 for (BuiltinCandidateTypeSet::iterator Ptr = 4688 CandidateTypes.member_pointer_begin(), 4689 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4690 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4691 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4692 } 4693 goto Conditional; 4694 } 4695} 4696 4697/// \brief Add function candidates found via argument-dependent lookup 4698/// to the set of overloading candidates. 4699/// 4700/// This routine performs argument-dependent name lookup based on the 4701/// given function name (which may also be an operator name) and adds 4702/// all of the overload candidates found by ADL to the overload 4703/// candidate set (C++ [basic.lookup.argdep]). 4704void 4705Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4706 bool Operator, 4707 Expr **Args, unsigned NumArgs, 4708 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4709 OverloadCandidateSet& CandidateSet, 4710 bool PartialOverloading) { 4711 ADLResult Fns; 4712 4713 // FIXME: This approach for uniquing ADL results (and removing 4714 // redundant candidates from the set) relies on pointer-equality, 4715 // which means we need to key off the canonical decl. However, 4716 // always going back to the canonical decl might not get us the 4717 // right set of default arguments. What default arguments are 4718 // we supposed to consider on ADL candidates, anyway? 4719 4720 // FIXME: Pass in the explicit template arguments? 4721 ArgumentDependentLookup(Name, Operator, Args, NumArgs, Fns); 4722 4723 // Erase all of the candidates we already knew about. 4724 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4725 CandEnd = CandidateSet.end(); 4726 Cand != CandEnd; ++Cand) 4727 if (Cand->Function) { 4728 Fns.erase(Cand->Function); 4729 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4730 Fns.erase(FunTmpl); 4731 } 4732 4733 // For each of the ADL candidates we found, add it to the overload 4734 // set. 4735 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 4736 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); 4737 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 4738 if (ExplicitTemplateArgs) 4739 continue; 4740 4741 AddOverloadCandidate(FD, FoundDecl, Args, NumArgs, CandidateSet, 4742 false, PartialOverloading); 4743 } else 4744 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), 4745 FoundDecl, ExplicitTemplateArgs, 4746 Args, NumArgs, CandidateSet); 4747 } 4748} 4749 4750/// isBetterOverloadCandidate - Determines whether the first overload 4751/// candidate is a better candidate than the second (C++ 13.3.3p1). 4752bool 4753Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4754 const OverloadCandidate& Cand2, 4755 SourceLocation Loc) { 4756 // Define viable functions to be better candidates than non-viable 4757 // functions. 4758 if (!Cand2.Viable) 4759 return Cand1.Viable; 4760 else if (!Cand1.Viable) 4761 return false; 4762 4763 // C++ [over.match.best]p1: 4764 // 4765 // -- if F is a static member function, ICS1(F) is defined such 4766 // that ICS1(F) is neither better nor worse than ICS1(G) for 4767 // any function G, and, symmetrically, ICS1(G) is neither 4768 // better nor worse than ICS1(F). 4769 unsigned StartArg = 0; 4770 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4771 StartArg = 1; 4772 4773 // C++ [over.match.best]p1: 4774 // A viable function F1 is defined to be a better function than another 4775 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4776 // conversion sequence than ICSi(F2), and then... 4777 unsigned NumArgs = Cand1.Conversions.size(); 4778 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4779 bool HasBetterConversion = false; 4780 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4781 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4782 Cand2.Conversions[ArgIdx])) { 4783 case ImplicitConversionSequence::Better: 4784 // Cand1 has a better conversion sequence. 4785 HasBetterConversion = true; 4786 break; 4787 4788 case ImplicitConversionSequence::Worse: 4789 // Cand1 can't be better than Cand2. 4790 return false; 4791 4792 case ImplicitConversionSequence::Indistinguishable: 4793 // Do nothing. 4794 break; 4795 } 4796 } 4797 4798 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4799 // ICSj(F2), or, if not that, 4800 if (HasBetterConversion) 4801 return true; 4802 4803 // - F1 is a non-template function and F2 is a function template 4804 // specialization, or, if not that, 4805 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4806 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4807 return true; 4808 4809 // -- F1 and F2 are function template specializations, and the function 4810 // template for F1 is more specialized than the template for F2 4811 // according to the partial ordering rules described in 14.5.5.2, or, 4812 // if not that, 4813 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4814 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4815 if (FunctionTemplateDecl *BetterTemplate 4816 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4817 Cand2.Function->getPrimaryTemplate(), 4818 Loc, 4819 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4820 : TPOC_Call)) 4821 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4822 4823 // -- the context is an initialization by user-defined conversion 4824 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4825 // from the return type of F1 to the destination type (i.e., 4826 // the type of the entity being initialized) is a better 4827 // conversion sequence than the standard conversion sequence 4828 // from the return type of F2 to the destination type. 4829 if (Cand1.Function && Cand2.Function && 4830 isa<CXXConversionDecl>(Cand1.Function) && 4831 isa<CXXConversionDecl>(Cand2.Function)) { 4832 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4833 Cand2.FinalConversion)) { 4834 case ImplicitConversionSequence::Better: 4835 // Cand1 has a better conversion sequence. 4836 return true; 4837 4838 case ImplicitConversionSequence::Worse: 4839 // Cand1 can't be better than Cand2. 4840 return false; 4841 4842 case ImplicitConversionSequence::Indistinguishable: 4843 // Do nothing 4844 break; 4845 } 4846 } 4847 4848 return false; 4849} 4850 4851/// \brief Computes the best viable function (C++ 13.3.3) 4852/// within an overload candidate set. 4853/// 4854/// \param CandidateSet the set of candidate functions. 4855/// 4856/// \param Loc the location of the function name (or operator symbol) for 4857/// which overload resolution occurs. 4858/// 4859/// \param Best f overload resolution was successful or found a deleted 4860/// function, Best points to the candidate function found. 4861/// 4862/// \returns The result of overload resolution. 4863OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4864 SourceLocation Loc, 4865 OverloadCandidateSet::iterator& Best) { 4866 // Find the best viable function. 4867 Best = CandidateSet.end(); 4868 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4869 Cand != CandidateSet.end(); ++Cand) { 4870 if (Cand->Viable) { 4871 if (Best == CandidateSet.end() || 4872 isBetterOverloadCandidate(*Cand, *Best, Loc)) 4873 Best = Cand; 4874 } 4875 } 4876 4877 // If we didn't find any viable functions, abort. 4878 if (Best == CandidateSet.end()) 4879 return OR_No_Viable_Function; 4880 4881 // Make sure that this function is better than every other viable 4882 // function. If not, we have an ambiguity. 4883 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4884 Cand != CandidateSet.end(); ++Cand) { 4885 if (Cand->Viable && 4886 Cand != Best && 4887 !isBetterOverloadCandidate(*Best, *Cand, Loc)) { 4888 Best = CandidateSet.end(); 4889 return OR_Ambiguous; 4890 } 4891 } 4892 4893 // Best is the best viable function. 4894 if (Best->Function && 4895 (Best->Function->isDeleted() || 4896 Best->Function->getAttr<UnavailableAttr>())) 4897 return OR_Deleted; 4898 4899 // C++ [basic.def.odr]p2: 4900 // An overloaded function is used if it is selected by overload resolution 4901 // when referred to from a potentially-evaluated expression. [Note: this 4902 // covers calls to named functions (5.2.2), operator overloading 4903 // (clause 13), user-defined conversions (12.3.2), allocation function for 4904 // placement new (5.3.4), as well as non-default initialization (8.5). 4905 if (Best->Function) 4906 MarkDeclarationReferenced(Loc, Best->Function); 4907 return OR_Success; 4908} 4909 4910namespace { 4911 4912enum OverloadCandidateKind { 4913 oc_function, 4914 oc_method, 4915 oc_constructor, 4916 oc_function_template, 4917 oc_method_template, 4918 oc_constructor_template, 4919 oc_implicit_default_constructor, 4920 oc_implicit_copy_constructor, 4921 oc_implicit_copy_assignment 4922}; 4923 4924OverloadCandidateKind ClassifyOverloadCandidate(Sema &S, 4925 FunctionDecl *Fn, 4926 std::string &Description) { 4927 bool isTemplate = false; 4928 4929 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { 4930 isTemplate = true; 4931 Description = S.getTemplateArgumentBindingsText( 4932 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); 4933 } 4934 4935 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4936 if (!Ctor->isImplicit()) 4937 return isTemplate ? oc_constructor_template : oc_constructor; 4938 4939 return Ctor->isCopyConstructor() ? oc_implicit_copy_constructor 4940 : oc_implicit_default_constructor; 4941 } 4942 4943 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4944 // This actually gets spelled 'candidate function' for now, but 4945 // it doesn't hurt to split it out. 4946 if (!Meth->isImplicit()) 4947 return isTemplate ? oc_method_template : oc_method; 4948 4949 assert(Meth->isCopyAssignment() 4950 && "implicit method is not copy assignment operator?"); 4951 return oc_implicit_copy_assignment; 4952 } 4953 4954 return isTemplate ? oc_function_template : oc_function; 4955} 4956 4957} // end anonymous namespace 4958 4959// Notes the location of an overload candidate. 4960void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4961 std::string FnDesc; 4962 OverloadCandidateKind K = ClassifyOverloadCandidate(*this, Fn, FnDesc); 4963 Diag(Fn->getLocation(), diag::note_ovl_candidate) 4964 << (unsigned) K << FnDesc; 4965} 4966 4967/// Diagnoses an ambiguous conversion. The partial diagnostic is the 4968/// "lead" diagnostic; it will be given two arguments, the source and 4969/// target types of the conversion. 4970void Sema::DiagnoseAmbiguousConversion(const ImplicitConversionSequence &ICS, 4971 SourceLocation CaretLoc, 4972 const PartialDiagnostic &PDiag) { 4973 Diag(CaretLoc, PDiag) 4974 << ICS.Ambiguous.getFromType() << ICS.Ambiguous.getToType(); 4975 for (AmbiguousConversionSequence::const_iterator 4976 I = ICS.Ambiguous.begin(), E = ICS.Ambiguous.end(); I != E; ++I) { 4977 NoteOverloadCandidate(*I); 4978 } 4979} 4980 4981namespace { 4982 4983void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I) { 4984 const ImplicitConversionSequence &Conv = Cand->Conversions[I]; 4985 assert(Conv.isBad()); 4986 assert(Cand->Function && "for now, candidate must be a function"); 4987 FunctionDecl *Fn = Cand->Function; 4988 4989 // There's a conversion slot for the object argument if this is a 4990 // non-constructor method. Note that 'I' corresponds the 4991 // conversion-slot index. 4992 bool isObjectArgument = false; 4993 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { 4994 if (I == 0) 4995 isObjectArgument = true; 4996 else 4997 I--; 4998 } 4999 5000 std::string FnDesc; 5001 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 5002 5003 Expr *FromExpr = Conv.Bad.FromExpr; 5004 QualType FromTy = Conv.Bad.getFromType(); 5005 QualType ToTy = Conv.Bad.getToType(); 5006 5007 if (FromTy == S.Context.OverloadTy) { 5008 assert(FromExpr && "overload set argument came from implicit argument?"); 5009 Expr *E = FromExpr->IgnoreParens(); 5010 if (isa<UnaryOperator>(E)) 5011 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 5012 DeclarationName Name = cast<OverloadExpr>(E)->getName(); 5013 5014 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) 5015 << (unsigned) FnKind << FnDesc 5016 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5017 << ToTy << Name << I+1; 5018 return; 5019 } 5020 5021 // Do some hand-waving analysis to see if the non-viability is due 5022 // to a qualifier mismatch. 5023 CanQualType CFromTy = S.Context.getCanonicalType(FromTy); 5024 CanQualType CToTy = S.Context.getCanonicalType(ToTy); 5025 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) 5026 CToTy = RT->getPointeeType(); 5027 else { 5028 // TODO: detect and diagnose the full richness of const mismatches. 5029 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) 5030 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) 5031 CFromTy = FromPT->getPointeeType(), CToTy = ToPT->getPointeeType(); 5032 } 5033 5034 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && 5035 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { 5036 // It is dumb that we have to do this here. 5037 while (isa<ArrayType>(CFromTy)) 5038 CFromTy = CFromTy->getAs<ArrayType>()->getElementType(); 5039 while (isa<ArrayType>(CToTy)) 5040 CToTy = CFromTy->getAs<ArrayType>()->getElementType(); 5041 5042 Qualifiers FromQs = CFromTy.getQualifiers(); 5043 Qualifiers ToQs = CToTy.getQualifiers(); 5044 5045 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { 5046 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) 5047 << (unsigned) FnKind << FnDesc 5048 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5049 << FromTy 5050 << FromQs.getAddressSpace() << ToQs.getAddressSpace() 5051 << (unsigned) isObjectArgument << I+1; 5052 return; 5053 } 5054 5055 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); 5056 assert(CVR && "unexpected qualifiers mismatch"); 5057 5058 if (isObjectArgument) { 5059 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) 5060 << (unsigned) FnKind << FnDesc 5061 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5062 << FromTy << (CVR - 1); 5063 } else { 5064 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) 5065 << (unsigned) FnKind << FnDesc 5066 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5067 << FromTy << (CVR - 1) << I+1; 5068 } 5069 return; 5070 } 5071 5072 // Diagnose references or pointers to incomplete types differently, 5073 // since it's far from impossible that the incompleteness triggered 5074 // the failure. 5075 QualType TempFromTy = FromTy.getNonReferenceType(); 5076 if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) 5077 TempFromTy = PTy->getPointeeType(); 5078 if (TempFromTy->isIncompleteType()) { 5079 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) 5080 << (unsigned) FnKind << FnDesc 5081 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5082 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 5083 return; 5084 } 5085 5086 // TODO: specialize more based on the kind of mismatch 5087 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv) 5088 << (unsigned) FnKind << FnDesc 5089 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5090 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 5091} 5092 5093void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, 5094 unsigned NumFormalArgs) { 5095 // TODO: treat calls to a missing default constructor as a special case 5096 5097 FunctionDecl *Fn = Cand->Function; 5098 const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); 5099 5100 unsigned MinParams = Fn->getMinRequiredArguments(); 5101 5102 // at least / at most / exactly 5103 // FIXME: variadic templates "at most" should account for parameter packs 5104 unsigned mode, modeCount; 5105 if (NumFormalArgs < MinParams) { 5106 assert((Cand->FailureKind == ovl_fail_too_few_arguments) || 5107 (Cand->FailureKind == ovl_fail_bad_deduction && 5108 Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments)); 5109 if (MinParams != FnTy->getNumArgs() || FnTy->isVariadic()) 5110 mode = 0; // "at least" 5111 else 5112 mode = 2; // "exactly" 5113 modeCount = MinParams; 5114 } else { 5115 assert((Cand->FailureKind == ovl_fail_too_many_arguments) || 5116 (Cand->FailureKind == ovl_fail_bad_deduction && 5117 Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments)); 5118 if (MinParams != FnTy->getNumArgs()) 5119 mode = 1; // "at most" 5120 else 5121 mode = 2; // "exactly" 5122 modeCount = FnTy->getNumArgs(); 5123 } 5124 5125 std::string Description; 5126 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, Description); 5127 5128 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) 5129 << (unsigned) FnKind << (Fn->getDescribedFunctionTemplate() != 0) << mode 5130 << modeCount << NumFormalArgs; 5131} 5132 5133/// Diagnose a failed template-argument deduction. 5134void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, 5135 Expr **Args, unsigned NumArgs) { 5136 FunctionDecl *Fn = Cand->Function; // pattern 5137 5138 TemplateParameter Param = Cand->DeductionFailure.getTemplateParameter(); 5139 NamedDecl *ParamD; 5140 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || 5141 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || 5142 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); 5143 switch (Cand->DeductionFailure.Result) { 5144 case Sema::TDK_Success: 5145 llvm_unreachable("TDK_success while diagnosing bad deduction"); 5146 5147 case Sema::TDK_Incomplete: { 5148 assert(ParamD && "no parameter found for incomplete deduction result"); 5149 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_incomplete_deduction) 5150 << ParamD->getDeclName(); 5151 return; 5152 } 5153 5154 case Sema::TDK_Inconsistent: 5155 case Sema::TDK_InconsistentQuals: { 5156 assert(ParamD && "no parameter found for inconsistent deduction result"); 5157 int which = 0; 5158 if (isa<TemplateTypeParmDecl>(ParamD)) 5159 which = 0; 5160 else if (isa<NonTypeTemplateParmDecl>(ParamD)) 5161 which = 1; 5162 else { 5163 which = 2; 5164 } 5165 5166 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_inconsistent_deduction) 5167 << which << ParamD->getDeclName() 5168 << *Cand->DeductionFailure.getFirstArg() 5169 << *Cand->DeductionFailure.getSecondArg(); 5170 return; 5171 } 5172 5173 case Sema::TDK_InvalidExplicitArguments: 5174 assert(ParamD && "no parameter found for invalid explicit arguments"); 5175 if (ParamD->getDeclName()) 5176 S.Diag(Fn->getLocation(), 5177 diag::note_ovl_candidate_explicit_arg_mismatch_named) 5178 << ParamD->getDeclName(); 5179 else { 5180 int index = 0; 5181 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD)) 5182 index = TTP->getIndex(); 5183 else if (NonTypeTemplateParmDecl *NTTP 5184 = dyn_cast<NonTypeTemplateParmDecl>(ParamD)) 5185 index = NTTP->getIndex(); 5186 else 5187 index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex(); 5188 S.Diag(Fn->getLocation(), 5189 diag::note_ovl_candidate_explicit_arg_mismatch_unnamed) 5190 << (index + 1); 5191 } 5192 return; 5193 5194 case Sema::TDK_TooManyArguments: 5195 case Sema::TDK_TooFewArguments: 5196 DiagnoseArityMismatch(S, Cand, NumArgs); 5197 return; 5198 5199 case Sema::TDK_InstantiationDepth: 5200 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_instantiation_depth); 5201 return; 5202 5203 case Sema::TDK_SubstitutionFailure: { 5204 std::string ArgString; 5205 if (TemplateArgumentList *Args 5206 = Cand->DeductionFailure.getTemplateArgumentList()) 5207 ArgString = S.getTemplateArgumentBindingsText( 5208 Fn->getDescribedFunctionTemplate()->getTemplateParameters(), 5209 *Args); 5210 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_substitution_failure) 5211 << ArgString; 5212 return; 5213 } 5214 5215 // TODO: diagnose these individually, then kill off 5216 // note_ovl_candidate_bad_deduction, which is uselessly vague. 5217 case Sema::TDK_NonDeducedMismatch: 5218 case Sema::TDK_FailedOverloadResolution: 5219 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction); 5220 return; 5221 } 5222} 5223 5224/// Generates a 'note' diagnostic for an overload candidate. We've 5225/// already generated a primary error at the call site. 5226/// 5227/// It really does need to be a single diagnostic with its caret 5228/// pointed at the candidate declaration. Yes, this creates some 5229/// major challenges of technical writing. Yes, this makes pointing 5230/// out problems with specific arguments quite awkward. It's still 5231/// better than generating twenty screens of text for every failed 5232/// overload. 5233/// 5234/// It would be great to be able to express per-candidate problems 5235/// more richly for those diagnostic clients that cared, but we'd 5236/// still have to be just as careful with the default diagnostics. 5237void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, 5238 Expr **Args, unsigned NumArgs) { 5239 FunctionDecl *Fn = Cand->Function; 5240 5241 // Note deleted candidates, but only if they're viable. 5242 if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) { 5243 std::string FnDesc; 5244 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 5245 5246 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) 5247 << FnKind << FnDesc << Fn->isDeleted(); 5248 return; 5249 } 5250 5251 // We don't really have anything else to say about viable candidates. 5252 if (Cand->Viable) { 5253 S.NoteOverloadCandidate(Fn); 5254 return; 5255 } 5256 5257 switch (Cand->FailureKind) { 5258 case ovl_fail_too_many_arguments: 5259 case ovl_fail_too_few_arguments: 5260 return DiagnoseArityMismatch(S, Cand, NumArgs); 5261 5262 case ovl_fail_bad_deduction: 5263 return DiagnoseBadDeduction(S, Cand, Args, NumArgs); 5264 5265 case ovl_fail_trivial_conversion: 5266 case ovl_fail_bad_final_conversion: 5267 case ovl_fail_final_conversion_not_exact: 5268 return S.NoteOverloadCandidate(Fn); 5269 5270 case ovl_fail_bad_conversion: { 5271 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); 5272 for (unsigned N = Cand->Conversions.size(); I != N; ++I) 5273 if (Cand->Conversions[I].isBad()) 5274 return DiagnoseBadConversion(S, Cand, I); 5275 5276 // FIXME: this currently happens when we're called from SemaInit 5277 // when user-conversion overload fails. Figure out how to handle 5278 // those conditions and diagnose them well. 5279 return S.NoteOverloadCandidate(Fn); 5280 } 5281 } 5282} 5283 5284void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 5285 // Desugar the type of the surrogate down to a function type, 5286 // retaining as many typedefs as possible while still showing 5287 // the function type (and, therefore, its parameter types). 5288 QualType FnType = Cand->Surrogate->getConversionType(); 5289 bool isLValueReference = false; 5290 bool isRValueReference = false; 5291 bool isPointer = false; 5292 if (const LValueReferenceType *FnTypeRef = 5293 FnType->getAs<LValueReferenceType>()) { 5294 FnType = FnTypeRef->getPointeeType(); 5295 isLValueReference = true; 5296 } else if (const RValueReferenceType *FnTypeRef = 5297 FnType->getAs<RValueReferenceType>()) { 5298 FnType = FnTypeRef->getPointeeType(); 5299 isRValueReference = true; 5300 } 5301 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 5302 FnType = FnTypePtr->getPointeeType(); 5303 isPointer = true; 5304 } 5305 // Desugar down to a function type. 5306 FnType = QualType(FnType->getAs<FunctionType>(), 0); 5307 // Reconstruct the pointer/reference as appropriate. 5308 if (isPointer) FnType = S.Context.getPointerType(FnType); 5309 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 5310 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 5311 5312 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 5313 << FnType; 5314} 5315 5316void NoteBuiltinOperatorCandidate(Sema &S, 5317 const char *Opc, 5318 SourceLocation OpLoc, 5319 OverloadCandidate *Cand) { 5320 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 5321 std::string TypeStr("operator"); 5322 TypeStr += Opc; 5323 TypeStr += "("; 5324 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 5325 if (Cand->Conversions.size() == 1) { 5326 TypeStr += ")"; 5327 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 5328 } else { 5329 TypeStr += ", "; 5330 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 5331 TypeStr += ")"; 5332 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 5333 } 5334} 5335 5336void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 5337 OverloadCandidate *Cand) { 5338 unsigned NoOperands = Cand->Conversions.size(); 5339 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 5340 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 5341 if (ICS.isBad()) break; // all meaningless after first invalid 5342 if (!ICS.isAmbiguous()) continue; 5343 5344 S.DiagnoseAmbiguousConversion(ICS, OpLoc, 5345 S.PDiag(diag::note_ambiguous_type_conversion)); 5346 } 5347} 5348 5349SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { 5350 if (Cand->Function) 5351 return Cand->Function->getLocation(); 5352 if (Cand->IsSurrogate) 5353 return Cand->Surrogate->getLocation(); 5354 return SourceLocation(); 5355} 5356 5357struct CompareOverloadCandidatesForDisplay { 5358 Sema &S; 5359 CompareOverloadCandidatesForDisplay(Sema &S) : S(S) {} 5360 5361 bool operator()(const OverloadCandidate *L, 5362 const OverloadCandidate *R) { 5363 // Fast-path this check. 5364 if (L == R) return false; 5365 5366 // Order first by viability. 5367 if (L->Viable) { 5368 if (!R->Viable) return true; 5369 5370 // TODO: introduce a tri-valued comparison for overload 5371 // candidates. Would be more worthwhile if we had a sort 5372 // that could exploit it. 5373 if (S.isBetterOverloadCandidate(*L, *R, SourceLocation())) return true; 5374 if (S.isBetterOverloadCandidate(*R, *L, SourceLocation())) return false; 5375 } else if (R->Viable) 5376 return false; 5377 5378 assert(L->Viable == R->Viable); 5379 5380 // Criteria by which we can sort non-viable candidates: 5381 if (!L->Viable) { 5382 // 1. Arity mismatches come after other candidates. 5383 if (L->FailureKind == ovl_fail_too_many_arguments || 5384 L->FailureKind == ovl_fail_too_few_arguments) 5385 return false; 5386 if (R->FailureKind == ovl_fail_too_many_arguments || 5387 R->FailureKind == ovl_fail_too_few_arguments) 5388 return true; 5389 5390 // 2. Bad conversions come first and are ordered by the number 5391 // of bad conversions and quality of good conversions. 5392 if (L->FailureKind == ovl_fail_bad_conversion) { 5393 if (R->FailureKind != ovl_fail_bad_conversion) 5394 return true; 5395 5396 // If there's any ordering between the defined conversions... 5397 // FIXME: this might not be transitive. 5398 assert(L->Conversions.size() == R->Conversions.size()); 5399 5400 int leftBetter = 0; 5401 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); 5402 for (unsigned E = L->Conversions.size(); I != E; ++I) { 5403 switch (S.CompareImplicitConversionSequences(L->Conversions[I], 5404 R->Conversions[I])) { 5405 case ImplicitConversionSequence::Better: 5406 leftBetter++; 5407 break; 5408 5409 case ImplicitConversionSequence::Worse: 5410 leftBetter--; 5411 break; 5412 5413 case ImplicitConversionSequence::Indistinguishable: 5414 break; 5415 } 5416 } 5417 if (leftBetter > 0) return true; 5418 if (leftBetter < 0) return false; 5419 5420 } else if (R->FailureKind == ovl_fail_bad_conversion) 5421 return false; 5422 5423 // TODO: others? 5424 } 5425 5426 // Sort everything else by location. 5427 SourceLocation LLoc = GetLocationForCandidate(L); 5428 SourceLocation RLoc = GetLocationForCandidate(R); 5429 5430 // Put candidates without locations (e.g. builtins) at the end. 5431 if (LLoc.isInvalid()) return false; 5432 if (RLoc.isInvalid()) return true; 5433 5434 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); 5435 } 5436}; 5437 5438/// CompleteNonViableCandidate - Normally, overload resolution only 5439/// computes up to the first 5440void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, 5441 Expr **Args, unsigned NumArgs) { 5442 assert(!Cand->Viable); 5443 5444 // Don't do anything on failures other than bad conversion. 5445 if (Cand->FailureKind != ovl_fail_bad_conversion) return; 5446 5447 // Skip forward to the first bad conversion. 5448 unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); 5449 unsigned ConvCount = Cand->Conversions.size(); 5450 while (true) { 5451 assert(ConvIdx != ConvCount && "no bad conversion in candidate"); 5452 ConvIdx++; 5453 if (Cand->Conversions[ConvIdx - 1].isBad()) 5454 break; 5455 } 5456 5457 if (ConvIdx == ConvCount) 5458 return; 5459 5460 assert(!Cand->Conversions[ConvIdx].isInitialized() && 5461 "remaining conversion is initialized?"); 5462 5463 // FIXME: this should probably be preserved from the overload 5464 // operation somehow. 5465 bool SuppressUserConversions = false; 5466 5467 const FunctionProtoType* Proto; 5468 unsigned ArgIdx = ConvIdx; 5469 5470 if (Cand->IsSurrogate) { 5471 QualType ConvType 5472 = Cand->Surrogate->getConversionType().getNonReferenceType(); 5473 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5474 ConvType = ConvPtrType->getPointeeType(); 5475 Proto = ConvType->getAs<FunctionProtoType>(); 5476 ArgIdx--; 5477 } else if (Cand->Function) { 5478 Proto = Cand->Function->getType()->getAs<FunctionProtoType>(); 5479 if (isa<CXXMethodDecl>(Cand->Function) && 5480 !isa<CXXConstructorDecl>(Cand->Function)) 5481 ArgIdx--; 5482 } else { 5483 // Builtin binary operator with a bad first conversion. 5484 assert(ConvCount <= 3); 5485 for (; ConvIdx != ConvCount; ++ConvIdx) 5486 Cand->Conversions[ConvIdx] 5487 = TryCopyInitialization(S, Args[ConvIdx], 5488 Cand->BuiltinTypes.ParamTypes[ConvIdx], 5489 SuppressUserConversions, 5490 /*InOverloadResolution*/ true); 5491 return; 5492 } 5493 5494 // Fill in the rest of the conversions. 5495 unsigned NumArgsInProto = Proto->getNumArgs(); 5496 for (; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { 5497 if (ArgIdx < NumArgsInProto) 5498 Cand->Conversions[ConvIdx] 5499 = TryCopyInitialization(S, Args[ArgIdx], Proto->getArgType(ArgIdx), 5500 SuppressUserConversions, 5501 /*InOverloadResolution=*/true); 5502 else 5503 Cand->Conversions[ConvIdx].setEllipsis(); 5504 } 5505} 5506 5507} // end anonymous namespace 5508 5509/// PrintOverloadCandidates - When overload resolution fails, prints 5510/// diagnostic messages containing the candidates in the candidate 5511/// set. 5512void 5513Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 5514 OverloadCandidateDisplayKind OCD, 5515 Expr **Args, unsigned NumArgs, 5516 const char *Opc, 5517 SourceLocation OpLoc) { 5518 // Sort the candidates by viability and position. Sorting directly would 5519 // be prohibitive, so we make a set of pointers and sort those. 5520 llvm::SmallVector<OverloadCandidate*, 32> Cands; 5521 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 5522 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 5523 LastCand = CandidateSet.end(); 5524 Cand != LastCand; ++Cand) { 5525 if (Cand->Viable) 5526 Cands.push_back(Cand); 5527 else if (OCD == OCD_AllCandidates) { 5528 CompleteNonViableCandidate(*this, Cand, Args, NumArgs); 5529 Cands.push_back(Cand); 5530 } 5531 } 5532 5533 std::sort(Cands.begin(), Cands.end(), 5534 CompareOverloadCandidatesForDisplay(*this)); 5535 5536 bool ReportedAmbiguousConversions = false; 5537 5538 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 5539 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 5540 OverloadCandidate *Cand = *I; 5541 5542 if (Cand->Function) 5543 NoteFunctionCandidate(*this, Cand, Args, NumArgs); 5544 else if (Cand->IsSurrogate) 5545 NoteSurrogateCandidate(*this, Cand); 5546 5547 // This a builtin candidate. We do not, in general, want to list 5548 // every possible builtin candidate. 5549 else if (Cand->Viable) { 5550 // Generally we only see ambiguities including viable builtin 5551 // operators if overload resolution got screwed up by an 5552 // ambiguous user-defined conversion. 5553 // 5554 // FIXME: It's quite possible for different conversions to see 5555 // different ambiguities, though. 5556 if (!ReportedAmbiguousConversions) { 5557 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 5558 ReportedAmbiguousConversions = true; 5559 } 5560 5561 // If this is a viable builtin, print it. 5562 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 5563 } 5564 } 5565} 5566 5567static bool CheckUnresolvedAccess(Sema &S, OverloadExpr *E, DeclAccessPair D) { 5568 if (isa<UnresolvedLookupExpr>(E)) 5569 return S.CheckUnresolvedLookupAccess(cast<UnresolvedLookupExpr>(E), D); 5570 5571 return S.CheckUnresolvedMemberAccess(cast<UnresolvedMemberExpr>(E), D); 5572} 5573 5574/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 5575/// an overloaded function (C++ [over.over]), where @p From is an 5576/// expression with overloaded function type and @p ToType is the type 5577/// we're trying to resolve to. For example: 5578/// 5579/// @code 5580/// int f(double); 5581/// int f(int); 5582/// 5583/// int (*pfd)(double) = f; // selects f(double) 5584/// @endcode 5585/// 5586/// This routine returns the resulting FunctionDecl if it could be 5587/// resolved, and NULL otherwise. When @p Complain is true, this 5588/// routine will emit diagnostics if there is an error. 5589FunctionDecl * 5590Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 5591 bool Complain, 5592 DeclAccessPair &FoundResult) { 5593 QualType FunctionType = ToType; 5594 bool IsMember = false; 5595 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 5596 FunctionType = ToTypePtr->getPointeeType(); 5597 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 5598 FunctionType = ToTypeRef->getPointeeType(); 5599 else if (const MemberPointerType *MemTypePtr = 5600 ToType->getAs<MemberPointerType>()) { 5601 FunctionType = MemTypePtr->getPointeeType(); 5602 IsMember = true; 5603 } 5604 5605 // C++ [over.over]p1: 5606 // [...] [Note: any redundant set of parentheses surrounding the 5607 // overloaded function name is ignored (5.1). ] 5608 // C++ [over.over]p1: 5609 // [...] The overloaded function name can be preceded by the & 5610 // operator. 5611 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5612 TemplateArgumentListInfo ETABuffer, *ExplicitTemplateArgs = 0; 5613 if (OvlExpr->hasExplicitTemplateArgs()) { 5614 OvlExpr->getExplicitTemplateArgs().copyInto(ETABuffer); 5615 ExplicitTemplateArgs = &ETABuffer; 5616 } 5617 5618 // We expect a pointer or reference to function, or a function pointer. 5619 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 5620 if (!FunctionType->isFunctionType()) { 5621 if (Complain) 5622 Diag(From->getLocStart(), diag::err_addr_ovl_not_func_ptrref) 5623 << OvlExpr->getName() << ToType; 5624 5625 return 0; 5626 } 5627 5628 assert(From->getType() == Context.OverloadTy); 5629 5630 // Look through all of the overloaded functions, searching for one 5631 // whose type matches exactly. 5632 llvm::SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; 5633 llvm::SmallVector<FunctionDecl *, 4> NonMatches; 5634 5635 bool FoundNonTemplateFunction = false; 5636 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5637 E = OvlExpr->decls_end(); I != E; ++I) { 5638 // Look through any using declarations to find the underlying function. 5639 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 5640 5641 // C++ [over.over]p3: 5642 // Non-member functions and static member functions match 5643 // targets of type "pointer-to-function" or "reference-to-function." 5644 // Nonstatic member functions match targets of 5645 // type "pointer-to-member-function." 5646 // Note that according to DR 247, the containing class does not matter. 5647 5648 if (FunctionTemplateDecl *FunctionTemplate 5649 = dyn_cast<FunctionTemplateDecl>(Fn)) { 5650 if (CXXMethodDecl *Method 5651 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 5652 // Skip non-static function templates when converting to pointer, and 5653 // static when converting to member pointer. 5654 if (Method->isStatic() == IsMember) 5655 continue; 5656 } else if (IsMember) 5657 continue; 5658 5659 // C++ [over.over]p2: 5660 // If the name is a function template, template argument deduction is 5661 // done (14.8.2.2), and if the argument deduction succeeds, the 5662 // resulting template argument list is used to generate a single 5663 // function template specialization, which is added to the set of 5664 // overloaded functions considered. 5665 // FIXME: We don't really want to build the specialization here, do we? 5666 FunctionDecl *Specialization = 0; 5667 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5668 if (TemplateDeductionResult Result 5669 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 5670 FunctionType, Specialization, Info)) { 5671 // FIXME: make a note of the failed deduction for diagnostics. 5672 (void)Result; 5673 } else { 5674 // FIXME: If the match isn't exact, shouldn't we just drop this as 5675 // a candidate? Find a testcase before changing the code. 5676 assert(FunctionType 5677 == Context.getCanonicalType(Specialization->getType())); 5678 Matches.push_back(std::make_pair(I.getPair(), 5679 cast<FunctionDecl>(Specialization->getCanonicalDecl()))); 5680 } 5681 5682 continue; 5683 } 5684 5685 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 5686 // Skip non-static functions when converting to pointer, and static 5687 // when converting to member pointer. 5688 if (Method->isStatic() == IsMember) 5689 continue; 5690 5691 // If we have explicit template arguments, skip non-templates. 5692 if (OvlExpr->hasExplicitTemplateArgs()) 5693 continue; 5694 } else if (IsMember) 5695 continue; 5696 5697 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 5698 QualType ResultTy; 5699 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 5700 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 5701 ResultTy)) { 5702 Matches.push_back(std::make_pair(I.getPair(), 5703 cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); 5704 FoundNonTemplateFunction = true; 5705 } 5706 } 5707 } 5708 5709 // If there were 0 or 1 matches, we're done. 5710 if (Matches.empty()) { 5711 if (Complain) { 5712 Diag(From->getLocStart(), diag::err_addr_ovl_no_viable) 5713 << OvlExpr->getName() << FunctionType; 5714 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5715 E = OvlExpr->decls_end(); 5716 I != E; ++I) 5717 if (FunctionDecl *F = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) 5718 NoteOverloadCandidate(F); 5719 } 5720 5721 return 0; 5722 } else if (Matches.size() == 1) { 5723 FunctionDecl *Result = Matches[0].second; 5724 FoundResult = Matches[0].first; 5725 MarkDeclarationReferenced(From->getLocStart(), Result); 5726 if (Complain) 5727 CheckAddressOfMemberAccess(OvlExpr, Matches[0].first); 5728 return Result; 5729 } 5730 5731 // C++ [over.over]p4: 5732 // If more than one function is selected, [...] 5733 if (!FoundNonTemplateFunction) { 5734 // [...] and any given function template specialization F1 is 5735 // eliminated if the set contains a second function template 5736 // specialization whose function template is more specialized 5737 // than the function template of F1 according to the partial 5738 // ordering rules of 14.5.5.2. 5739 5740 // The algorithm specified above is quadratic. We instead use a 5741 // two-pass algorithm (similar to the one used to identify the 5742 // best viable function in an overload set) that identifies the 5743 // best function template (if it exists). 5744 5745 UnresolvedSet<4> MatchesCopy; // TODO: avoid! 5746 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5747 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); 5748 5749 UnresolvedSetIterator Result = 5750 getMostSpecialized(MatchesCopy.begin(), MatchesCopy.end(), 5751 TPOC_Other, From->getLocStart(), 5752 PDiag(), 5753 PDiag(diag::err_addr_ovl_ambiguous) 5754 << Matches[0].second->getDeclName(), 5755 PDiag(diag::note_ovl_candidate) 5756 << (unsigned) oc_function_template); 5757 assert(Result != MatchesCopy.end() && "no most-specialized template"); 5758 MarkDeclarationReferenced(From->getLocStart(), *Result); 5759 FoundResult = Matches[Result - MatchesCopy.begin()].first; 5760 if (Complain) { 5761 CheckUnresolvedAccess(*this, OvlExpr, FoundResult); 5762 DiagnoseUseOfDecl(FoundResult, OvlExpr->getNameLoc()); 5763 } 5764 return cast<FunctionDecl>(*Result); 5765 } 5766 5767 // [...] any function template specializations in the set are 5768 // eliminated if the set also contains a non-template function, [...] 5769 for (unsigned I = 0, N = Matches.size(); I != N; ) { 5770 if (Matches[I].second->getPrimaryTemplate() == 0) 5771 ++I; 5772 else { 5773 Matches[I] = Matches[--N]; 5774 Matches.set_size(N); 5775 } 5776 } 5777 5778 // [...] After such eliminations, if any, there shall remain exactly one 5779 // selected function. 5780 if (Matches.size() == 1) { 5781 MarkDeclarationReferenced(From->getLocStart(), Matches[0].second); 5782 FoundResult = Matches[0].first; 5783 if (Complain) { 5784 CheckUnresolvedAccess(*this, OvlExpr, Matches[0].first); 5785 DiagnoseUseOfDecl(Matches[0].first, OvlExpr->getNameLoc()); 5786 } 5787 return cast<FunctionDecl>(Matches[0].second); 5788 } 5789 5790 // FIXME: We should probably return the same thing that BestViableFunction 5791 // returns (even if we issue the diagnostics here). 5792 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 5793 << Matches[0].second->getDeclName(); 5794 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5795 NoteOverloadCandidate(Matches[I].second); 5796 return 0; 5797} 5798 5799/// \brief Given an expression that refers to an overloaded function, try to 5800/// resolve that overloaded function expression down to a single function. 5801/// 5802/// This routine can only resolve template-ids that refer to a single function 5803/// template, where that template-id refers to a single template whose template 5804/// arguments are either provided by the template-id or have defaults, 5805/// as described in C++0x [temp.arg.explicit]p3. 5806FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 5807 // C++ [over.over]p1: 5808 // [...] [Note: any redundant set of parentheses surrounding the 5809 // overloaded function name is ignored (5.1). ] 5810 // C++ [over.over]p1: 5811 // [...] The overloaded function name can be preceded by the & 5812 // operator. 5813 5814 if (From->getType() != Context.OverloadTy) 5815 return 0; 5816 5817 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5818 5819 // If we didn't actually find any template-ids, we're done. 5820 if (!OvlExpr->hasExplicitTemplateArgs()) 5821 return 0; 5822 5823 TemplateArgumentListInfo ExplicitTemplateArgs; 5824 OvlExpr->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 5825 5826 // Look through all of the overloaded functions, searching for one 5827 // whose type matches exactly. 5828 FunctionDecl *Matched = 0; 5829 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5830 E = OvlExpr->decls_end(); I != E; ++I) { 5831 // C++0x [temp.arg.explicit]p3: 5832 // [...] In contexts where deduction is done and fails, or in contexts 5833 // where deduction is not done, if a template argument list is 5834 // specified and it, along with any default template arguments, 5835 // identifies a single function template specialization, then the 5836 // template-id is an lvalue for the function template specialization. 5837 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 5838 5839 // C++ [over.over]p2: 5840 // If the name is a function template, template argument deduction is 5841 // done (14.8.2.2), and if the argument deduction succeeds, the 5842 // resulting template argument list is used to generate a single 5843 // function template specialization, which is added to the set of 5844 // overloaded functions considered. 5845 FunctionDecl *Specialization = 0; 5846 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5847 if (TemplateDeductionResult Result 5848 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 5849 Specialization, Info)) { 5850 // FIXME: make a note of the failed deduction for diagnostics. 5851 (void)Result; 5852 continue; 5853 } 5854 5855 // Multiple matches; we can't resolve to a single declaration. 5856 if (Matched) 5857 return 0; 5858 5859 Matched = Specialization; 5860 } 5861 5862 return Matched; 5863} 5864 5865/// \brief Add a single candidate to the overload set. 5866static void AddOverloadedCallCandidate(Sema &S, 5867 DeclAccessPair FoundDecl, 5868 const TemplateArgumentListInfo *ExplicitTemplateArgs, 5869 Expr **Args, unsigned NumArgs, 5870 OverloadCandidateSet &CandidateSet, 5871 bool PartialOverloading) { 5872 NamedDecl *Callee = FoundDecl.getDecl(); 5873 if (isa<UsingShadowDecl>(Callee)) 5874 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 5875 5876 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 5877 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 5878 S.AddOverloadCandidate(Func, FoundDecl, Args, NumArgs, CandidateSet, 5879 false, PartialOverloading); 5880 return; 5881 } 5882 5883 if (FunctionTemplateDecl *FuncTemplate 5884 = dyn_cast<FunctionTemplateDecl>(Callee)) { 5885 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, 5886 ExplicitTemplateArgs, 5887 Args, NumArgs, CandidateSet); 5888 return; 5889 } 5890 5891 assert(false && "unhandled case in overloaded call candidate"); 5892 5893 // do nothing? 5894} 5895 5896/// \brief Add the overload candidates named by callee and/or found by argument 5897/// dependent lookup to the given overload set. 5898void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 5899 Expr **Args, unsigned NumArgs, 5900 OverloadCandidateSet &CandidateSet, 5901 bool PartialOverloading) { 5902 5903#ifndef NDEBUG 5904 // Verify that ArgumentDependentLookup is consistent with the rules 5905 // in C++0x [basic.lookup.argdep]p3: 5906 // 5907 // Let X be the lookup set produced by unqualified lookup (3.4.1) 5908 // and let Y be the lookup set produced by argument dependent 5909 // lookup (defined as follows). If X contains 5910 // 5911 // -- a declaration of a class member, or 5912 // 5913 // -- a block-scope function declaration that is not a 5914 // using-declaration, or 5915 // 5916 // -- a declaration that is neither a function or a function 5917 // template 5918 // 5919 // then Y is empty. 5920 5921 if (ULE->requiresADL()) { 5922 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5923 E = ULE->decls_end(); I != E; ++I) { 5924 assert(!(*I)->getDeclContext()->isRecord()); 5925 assert(isa<UsingShadowDecl>(*I) || 5926 !(*I)->getDeclContext()->isFunctionOrMethod()); 5927 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 5928 } 5929 } 5930#endif 5931 5932 // It would be nice to avoid this copy. 5933 TemplateArgumentListInfo TABuffer; 5934 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5935 if (ULE->hasExplicitTemplateArgs()) { 5936 ULE->copyTemplateArgumentsInto(TABuffer); 5937 ExplicitTemplateArgs = &TABuffer; 5938 } 5939 5940 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5941 E = ULE->decls_end(); I != E; ++I) 5942 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, 5943 Args, NumArgs, CandidateSet, 5944 PartialOverloading); 5945 5946 if (ULE->requiresADL()) 5947 AddArgumentDependentLookupCandidates(ULE->getName(), /*Operator*/ false, 5948 Args, NumArgs, 5949 ExplicitTemplateArgs, 5950 CandidateSet, 5951 PartialOverloading); 5952} 5953 5954static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 5955 Expr **Args, unsigned NumArgs) { 5956 Fn->Destroy(SemaRef.Context); 5957 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5958 Args[Arg]->Destroy(SemaRef.Context); 5959 return SemaRef.ExprError(); 5960} 5961 5962/// Attempts to recover from a call where no functions were found. 5963/// 5964/// Returns true if new candidates were found. 5965static Sema::OwningExprResult 5966BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, 5967 UnresolvedLookupExpr *ULE, 5968 SourceLocation LParenLoc, 5969 Expr **Args, unsigned NumArgs, 5970 SourceLocation *CommaLocs, 5971 SourceLocation RParenLoc) { 5972 5973 CXXScopeSpec SS; 5974 if (ULE->getQualifier()) { 5975 SS.setScopeRep(ULE->getQualifier()); 5976 SS.setRange(ULE->getQualifierRange()); 5977 } 5978 5979 TemplateArgumentListInfo TABuffer; 5980 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5981 if (ULE->hasExplicitTemplateArgs()) { 5982 ULE->copyTemplateArgumentsInto(TABuffer); 5983 ExplicitTemplateArgs = &TABuffer; 5984 } 5985 5986 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 5987 Sema::LookupOrdinaryName); 5988 if (SemaRef.DiagnoseEmptyLookup(S, SS, R)) 5989 return Destroy(SemaRef, Fn, Args, NumArgs); 5990 5991 assert(!R.empty() && "lookup results empty despite recovery"); 5992 5993 // Build an implicit member call if appropriate. Just drop the 5994 // casts and such from the call, we don't really care. 5995 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 5996 if ((*R.begin())->isCXXClassMember()) 5997 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 5998 else if (ExplicitTemplateArgs) 5999 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 6000 else 6001 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 6002 6003 if (NewFn.isInvalid()) 6004 return Destroy(SemaRef, Fn, Args, NumArgs); 6005 6006 Fn->Destroy(SemaRef.Context); 6007 6008 // This shouldn't cause an infinite loop because we're giving it 6009 // an expression with non-empty lookup results, which should never 6010 // end up here. 6011 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 6012 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 6013 CommaLocs, RParenLoc); 6014} 6015 6016/// ResolveOverloadedCallFn - Given the call expression that calls Fn 6017/// (which eventually refers to the declaration Func) and the call 6018/// arguments Args/NumArgs, attempt to resolve the function call down 6019/// to a specific function. If overload resolution succeeds, returns 6020/// the function declaration produced by overload 6021/// resolution. Otherwise, emits diagnostics, deletes all of the 6022/// arguments and Fn, and returns NULL. 6023Sema::OwningExprResult 6024Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, 6025 SourceLocation LParenLoc, 6026 Expr **Args, unsigned NumArgs, 6027 SourceLocation *CommaLocs, 6028 SourceLocation RParenLoc) { 6029#ifndef NDEBUG 6030 if (ULE->requiresADL()) { 6031 // To do ADL, we must have found an unqualified name. 6032 assert(!ULE->getQualifier() && "qualified name with ADL"); 6033 6034 // We don't perform ADL for implicit declarations of builtins. 6035 // Verify that this was correctly set up. 6036 FunctionDecl *F; 6037 if (ULE->decls_begin() + 1 == ULE->decls_end() && 6038 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 6039 F->getBuiltinID() && F->isImplicit()) 6040 assert(0 && "performing ADL for builtin"); 6041 6042 // We don't perform ADL in C. 6043 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 6044 } 6045#endif 6046 6047 OverloadCandidateSet CandidateSet(Fn->getExprLoc()); 6048 6049 // Add the functions denoted by the callee to the set of candidate 6050 // functions, including those from argument-dependent lookup. 6051 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 6052 6053 // If we found nothing, try to recover. 6054 // AddRecoveryCallCandidates diagnoses the error itself, so we just 6055 // bailout out if it fails. 6056 if (CandidateSet.empty()) 6057 return BuildRecoveryCallExpr(*this, S, Fn, ULE, LParenLoc, Args, NumArgs, 6058 CommaLocs, RParenLoc); 6059 6060 OverloadCandidateSet::iterator Best; 6061 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 6062 case OR_Success: { 6063 FunctionDecl *FDecl = Best->Function; 6064 CheckUnresolvedLookupAccess(ULE, Best->FoundDecl); 6065 DiagnoseUseOfDecl(Best->FoundDecl, ULE->getNameLoc()); 6066 Fn = FixOverloadedFunctionReference(Fn, Best->FoundDecl, FDecl); 6067 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 6068 } 6069 6070 case OR_No_Viable_Function: 6071 Diag(Fn->getSourceRange().getBegin(), 6072 diag::err_ovl_no_viable_function_in_call) 6073 << ULE->getName() << Fn->getSourceRange(); 6074 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6075 break; 6076 6077 case OR_Ambiguous: 6078 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 6079 << ULE->getName() << Fn->getSourceRange(); 6080 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6081 break; 6082 6083 case OR_Deleted: 6084 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 6085 << Best->Function->isDeleted() 6086 << ULE->getName() 6087 << Fn->getSourceRange(); 6088 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6089 break; 6090 } 6091 6092 // Overload resolution failed. Destroy all of the subexpressions and 6093 // return NULL. 6094 Fn->Destroy(Context); 6095 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 6096 Args[Arg]->Destroy(Context); 6097 return ExprError(); 6098} 6099 6100static bool IsOverloaded(const UnresolvedSetImpl &Functions) { 6101 return Functions.size() > 1 || 6102 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 6103} 6104 6105/// \brief Create a unary operation that may resolve to an overloaded 6106/// operator. 6107/// 6108/// \param OpLoc The location of the operator itself (e.g., '*'). 6109/// 6110/// \param OpcIn The UnaryOperator::Opcode that describes this 6111/// operator. 6112/// 6113/// \param Functions The set of non-member functions that will be 6114/// considered by overload resolution. The caller needs to build this 6115/// set based on the context using, e.g., 6116/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 6117/// set should not contain any member functions; those will be added 6118/// by CreateOverloadedUnaryOp(). 6119/// 6120/// \param input The input argument. 6121Sema::OwningExprResult 6122Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn, 6123 const UnresolvedSetImpl &Fns, 6124 ExprArg input) { 6125 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 6126 Expr *Input = (Expr *)input.get(); 6127 6128 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 6129 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 6130 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 6131 6132 Expr *Args[2] = { Input, 0 }; 6133 unsigned NumArgs = 1; 6134 6135 // For post-increment and post-decrement, add the implicit '0' as 6136 // the second argument, so that we know this is a post-increment or 6137 // post-decrement. 6138 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 6139 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 6140 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 6141 SourceLocation()); 6142 NumArgs = 2; 6143 } 6144 6145 if (Input->isTypeDependent()) { 6146 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6147 UnresolvedLookupExpr *Fn 6148 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6149 0, SourceRange(), OpName, OpLoc, 6150 /*ADL*/ true, IsOverloaded(Fns)); 6151 Fn->addDecls(Fns.begin(), Fns.end()); 6152 6153 input.release(); 6154 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6155 &Args[0], NumArgs, 6156 Context.DependentTy, 6157 OpLoc)); 6158 } 6159 6160 // Build an empty overload set. 6161 OverloadCandidateSet CandidateSet(OpLoc); 6162 6163 // Add the candidates from the given function set. 6164 AddFunctionCandidates(Fns, &Args[0], NumArgs, CandidateSet, false); 6165 6166 // Add operator candidates that are member functions. 6167 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 6168 6169 // Add candidates from ADL. 6170 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6171 Args, NumArgs, 6172 /*ExplicitTemplateArgs*/ 0, 6173 CandidateSet); 6174 6175 // Add builtin operator candidates. 6176 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 6177 6178 // Perform overload resolution. 6179 OverloadCandidateSet::iterator Best; 6180 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6181 case OR_Success: { 6182 // We found a built-in operator or an overloaded operator. 6183 FunctionDecl *FnDecl = Best->Function; 6184 6185 if (FnDecl) { 6186 // We matched an overloaded operator. Build a call to that 6187 // operator. 6188 6189 // Convert the arguments. 6190 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6191 CheckMemberOperatorAccess(OpLoc, Args[0], 0, Best->FoundDecl); 6192 6193 if (PerformObjectArgumentInitialization(Input, /*Qualifier=*/0, 6194 Best->FoundDecl, Method)) 6195 return ExprError(); 6196 } else { 6197 // Convert the arguments. 6198 OwningExprResult InputInit 6199 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6200 FnDecl->getParamDecl(0)), 6201 SourceLocation(), 6202 move(input)); 6203 if (InputInit.isInvalid()) 6204 return ExprError(); 6205 6206 input = move(InputInit); 6207 Input = (Expr *)input.get(); 6208 } 6209 6210 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 6211 6212 // Determine the result type 6213 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 6214 6215 // Build the actual expression node. 6216 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6217 SourceLocation()); 6218 UsualUnaryConversions(FnExpr); 6219 6220 input.release(); 6221 Args[0] = Input; 6222 ExprOwningPtr<CallExpr> TheCall(this, 6223 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6224 Args, NumArgs, ResultTy, OpLoc)); 6225 6226 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6227 FnDecl)) 6228 return ExprError(); 6229 6230 return MaybeBindToTemporary(TheCall.release()); 6231 } else { 6232 // We matched a built-in operator. Convert the arguments, then 6233 // break out so that we will build the appropriate built-in 6234 // operator node. 6235 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 6236 Best->Conversions[0], AA_Passing)) 6237 return ExprError(); 6238 6239 break; 6240 } 6241 } 6242 6243 case OR_No_Viable_Function: 6244 // No viable function; fall through to handling this as a 6245 // built-in operator, which will produce an error message for us. 6246 break; 6247 6248 case OR_Ambiguous: 6249 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6250 << UnaryOperator::getOpcodeStr(Opc) 6251 << Input->getSourceRange(); 6252 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs, 6253 UnaryOperator::getOpcodeStr(Opc), OpLoc); 6254 return ExprError(); 6255 6256 case OR_Deleted: 6257 Diag(OpLoc, diag::err_ovl_deleted_oper) 6258 << Best->Function->isDeleted() 6259 << UnaryOperator::getOpcodeStr(Opc) 6260 << Input->getSourceRange(); 6261 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6262 return ExprError(); 6263 } 6264 6265 // Either we found no viable overloaded operator or we matched a 6266 // built-in operator. In either case, fall through to trying to 6267 // build a built-in operation. 6268 input.release(); 6269 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 6270} 6271 6272/// \brief Create a binary operation that may resolve to an overloaded 6273/// operator. 6274/// 6275/// \param OpLoc The location of the operator itself (e.g., '+'). 6276/// 6277/// \param OpcIn The BinaryOperator::Opcode that describes this 6278/// operator. 6279/// 6280/// \param Functions The set of non-member functions that will be 6281/// considered by overload resolution. The caller needs to build this 6282/// set based on the context using, e.g., 6283/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 6284/// set should not contain any member functions; those will be added 6285/// by CreateOverloadedBinOp(). 6286/// 6287/// \param LHS Left-hand argument. 6288/// \param RHS Right-hand argument. 6289Sema::OwningExprResult 6290Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 6291 unsigned OpcIn, 6292 const UnresolvedSetImpl &Fns, 6293 Expr *LHS, Expr *RHS) { 6294 Expr *Args[2] = { LHS, RHS }; 6295 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 6296 6297 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 6298 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 6299 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 6300 6301 // If either side is type-dependent, create an appropriate dependent 6302 // expression. 6303 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6304 if (Fns.empty()) { 6305 // If there are no functions to store, just build a dependent 6306 // BinaryOperator or CompoundAssignment. 6307 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 6308 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 6309 Context.DependentTy, OpLoc)); 6310 6311 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 6312 Context.DependentTy, 6313 Context.DependentTy, 6314 Context.DependentTy, 6315 OpLoc)); 6316 } 6317 6318 // FIXME: save results of ADL from here? 6319 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6320 UnresolvedLookupExpr *Fn 6321 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6322 0, SourceRange(), OpName, OpLoc, 6323 /*ADL*/ true, IsOverloaded(Fns)); 6324 6325 Fn->addDecls(Fns.begin(), Fns.end()); 6326 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6327 Args, 2, 6328 Context.DependentTy, 6329 OpLoc)); 6330 } 6331 6332 // If this is the .* operator, which is not overloadable, just 6333 // create a built-in binary operator. 6334 if (Opc == BinaryOperator::PtrMemD) 6335 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6336 6337 // If this is the assignment operator, we only perform overload resolution 6338 // if the left-hand side is a class or enumeration type. This is actually 6339 // a hack. The standard requires that we do overload resolution between the 6340 // various built-in candidates, but as DR507 points out, this can lead to 6341 // problems. So we do it this way, which pretty much follows what GCC does. 6342 // Note that we go the traditional code path for compound assignment forms. 6343 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 6344 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6345 6346 // Build an empty overload set. 6347 OverloadCandidateSet CandidateSet(OpLoc); 6348 6349 // Add the candidates from the given function set. 6350 AddFunctionCandidates(Fns, Args, 2, CandidateSet, false); 6351 6352 // Add operator candidates that are member functions. 6353 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6354 6355 // Add candidates from ADL. 6356 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6357 Args, 2, 6358 /*ExplicitTemplateArgs*/ 0, 6359 CandidateSet); 6360 6361 // Add builtin operator candidates. 6362 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6363 6364 // Perform overload resolution. 6365 OverloadCandidateSet::iterator Best; 6366 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6367 case OR_Success: { 6368 // We found a built-in operator or an overloaded operator. 6369 FunctionDecl *FnDecl = Best->Function; 6370 6371 if (FnDecl) { 6372 // We matched an overloaded operator. Build a call to that 6373 // operator. 6374 6375 // Convert the arguments. 6376 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6377 // Best->Access is only meaningful for class members. 6378 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); 6379 6380 OwningExprResult Arg1 6381 = PerformCopyInitialization( 6382 InitializedEntity::InitializeParameter( 6383 FnDecl->getParamDecl(0)), 6384 SourceLocation(), 6385 Owned(Args[1])); 6386 if (Arg1.isInvalid()) 6387 return ExprError(); 6388 6389 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6390 Best->FoundDecl, Method)) 6391 return ExprError(); 6392 6393 Args[1] = RHS = Arg1.takeAs<Expr>(); 6394 } else { 6395 // Convert the arguments. 6396 OwningExprResult Arg0 6397 = PerformCopyInitialization( 6398 InitializedEntity::InitializeParameter( 6399 FnDecl->getParamDecl(0)), 6400 SourceLocation(), 6401 Owned(Args[0])); 6402 if (Arg0.isInvalid()) 6403 return ExprError(); 6404 6405 OwningExprResult Arg1 6406 = PerformCopyInitialization( 6407 InitializedEntity::InitializeParameter( 6408 FnDecl->getParamDecl(1)), 6409 SourceLocation(), 6410 Owned(Args[1])); 6411 if (Arg1.isInvalid()) 6412 return ExprError(); 6413 Args[0] = LHS = Arg0.takeAs<Expr>(); 6414 Args[1] = RHS = Arg1.takeAs<Expr>(); 6415 } 6416 6417 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 6418 6419 // Determine the result type 6420 QualType ResultTy 6421 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6422 ResultTy = ResultTy.getNonReferenceType(); 6423 6424 // Build the actual expression node. 6425 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6426 OpLoc); 6427 UsualUnaryConversions(FnExpr); 6428 6429 ExprOwningPtr<CXXOperatorCallExpr> 6430 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6431 Args, 2, ResultTy, 6432 OpLoc)); 6433 6434 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6435 FnDecl)) 6436 return ExprError(); 6437 6438 return MaybeBindToTemporary(TheCall.release()); 6439 } else { 6440 // We matched a built-in operator. Convert the arguments, then 6441 // break out so that we will build the appropriate built-in 6442 // operator node. 6443 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6444 Best->Conversions[0], AA_Passing) || 6445 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6446 Best->Conversions[1], AA_Passing)) 6447 return ExprError(); 6448 6449 break; 6450 } 6451 } 6452 6453 case OR_No_Viable_Function: { 6454 // C++ [over.match.oper]p9: 6455 // If the operator is the operator , [...] and there are no 6456 // viable functions, then the operator is assumed to be the 6457 // built-in operator and interpreted according to clause 5. 6458 if (Opc == BinaryOperator::Comma) 6459 break; 6460 6461 // For class as left operand for assignment or compound assigment operator 6462 // do not fall through to handling in built-in, but report that no overloaded 6463 // assignment operator found 6464 OwningExprResult Result = ExprError(); 6465 if (Args[0]->getType()->isRecordType() && 6466 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 6467 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6468 << BinaryOperator::getOpcodeStr(Opc) 6469 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6470 } else { 6471 // No viable function; try to create a built-in operation, which will 6472 // produce an error. Then, show the non-viable candidates. 6473 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6474 } 6475 assert(Result.isInvalid() && 6476 "C++ binary operator overloading is missing candidates!"); 6477 if (Result.isInvalid()) 6478 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6479 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6480 return move(Result); 6481 } 6482 6483 case OR_Ambiguous: 6484 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6485 << BinaryOperator::getOpcodeStr(Opc) 6486 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6487 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6488 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6489 return ExprError(); 6490 6491 case OR_Deleted: 6492 Diag(OpLoc, diag::err_ovl_deleted_oper) 6493 << Best->Function->isDeleted() 6494 << BinaryOperator::getOpcodeStr(Opc) 6495 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6496 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2); 6497 return ExprError(); 6498 } 6499 6500 // We matched a built-in operator; build it. 6501 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6502} 6503 6504Action::OwningExprResult 6505Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 6506 SourceLocation RLoc, 6507 ExprArg Base, ExprArg Idx) { 6508 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 6509 static_cast<Expr*>(Idx.get()) }; 6510 DeclarationName OpName = 6511 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 6512 6513 // If either side is type-dependent, create an appropriate dependent 6514 // expression. 6515 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6516 6517 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6518 UnresolvedLookupExpr *Fn 6519 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6520 0, SourceRange(), OpName, LLoc, 6521 /*ADL*/ true, /*Overloaded*/ false); 6522 // Can't add any actual overloads yet 6523 6524 Base.release(); 6525 Idx.release(); 6526 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 6527 Args, 2, 6528 Context.DependentTy, 6529 RLoc)); 6530 } 6531 6532 // Build an empty overload set. 6533 OverloadCandidateSet CandidateSet(LLoc); 6534 6535 // Subscript can only be overloaded as a member function. 6536 6537 // Add operator candidates that are member functions. 6538 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6539 6540 // Add builtin operator candidates. 6541 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6542 6543 // Perform overload resolution. 6544 OverloadCandidateSet::iterator Best; 6545 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 6546 case OR_Success: { 6547 // We found a built-in operator or an overloaded operator. 6548 FunctionDecl *FnDecl = Best->Function; 6549 6550 if (FnDecl) { 6551 // We matched an overloaded operator. Build a call to that 6552 // operator. 6553 6554 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); 6555 DiagnoseUseOfDecl(Best->FoundDecl, LLoc); 6556 6557 // Convert the arguments. 6558 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 6559 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6560 Best->FoundDecl, Method)) 6561 return ExprError(); 6562 6563 // Convert the arguments. 6564 OwningExprResult InputInit 6565 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6566 FnDecl->getParamDecl(0)), 6567 SourceLocation(), 6568 Owned(Args[1])); 6569 if (InputInit.isInvalid()) 6570 return ExprError(); 6571 6572 Args[1] = InputInit.takeAs<Expr>(); 6573 6574 // Determine the result type 6575 QualType ResultTy 6576 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6577 ResultTy = ResultTy.getNonReferenceType(); 6578 6579 // Build the actual expression node. 6580 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6581 LLoc); 6582 UsualUnaryConversions(FnExpr); 6583 6584 Base.release(); 6585 Idx.release(); 6586 ExprOwningPtr<CXXOperatorCallExpr> 6587 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 6588 FnExpr, Args, 2, 6589 ResultTy, RLoc)); 6590 6591 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 6592 FnDecl)) 6593 return ExprError(); 6594 6595 return MaybeBindToTemporary(TheCall.release()); 6596 } else { 6597 // We matched a built-in operator. Convert the arguments, then 6598 // break out so that we will build the appropriate built-in 6599 // operator node. 6600 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6601 Best->Conversions[0], AA_Passing) || 6602 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6603 Best->Conversions[1], AA_Passing)) 6604 return ExprError(); 6605 6606 break; 6607 } 6608 } 6609 6610 case OR_No_Viable_Function: { 6611 if (CandidateSet.empty()) 6612 Diag(LLoc, diag::err_ovl_no_oper) 6613 << Args[0]->getType() << /*subscript*/ 0 6614 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6615 else 6616 Diag(LLoc, diag::err_ovl_no_viable_subscript) 6617 << Args[0]->getType() 6618 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6619 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6620 "[]", LLoc); 6621 return ExprError(); 6622 } 6623 6624 case OR_Ambiguous: 6625 Diag(LLoc, diag::err_ovl_ambiguous_oper) 6626 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6627 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6628 "[]", LLoc); 6629 return ExprError(); 6630 6631 case OR_Deleted: 6632 Diag(LLoc, diag::err_ovl_deleted_oper) 6633 << Best->Function->isDeleted() << "[]" 6634 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6635 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6636 "[]", LLoc); 6637 return ExprError(); 6638 } 6639 6640 // We matched a built-in operator; build it. 6641 Base.release(); 6642 Idx.release(); 6643 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 6644 Owned(Args[1]), RLoc); 6645} 6646 6647/// BuildCallToMemberFunction - Build a call to a member 6648/// function. MemExpr is the expression that refers to the member 6649/// function (and includes the object parameter), Args/NumArgs are the 6650/// arguments to the function call (not including the object 6651/// parameter). The caller needs to validate that the member 6652/// expression refers to a member function or an overloaded member 6653/// function. 6654Sema::OwningExprResult 6655Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 6656 SourceLocation LParenLoc, Expr **Args, 6657 unsigned NumArgs, SourceLocation *CommaLocs, 6658 SourceLocation RParenLoc) { 6659 // Dig out the member expression. This holds both the object 6660 // argument and the member function we're referring to. 6661 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 6662 6663 MemberExpr *MemExpr; 6664 CXXMethodDecl *Method = 0; 6665 DeclAccessPair FoundDecl = DeclAccessPair::make(0, AS_public); 6666 NestedNameSpecifier *Qualifier = 0; 6667 if (isa<MemberExpr>(NakedMemExpr)) { 6668 MemExpr = cast<MemberExpr>(NakedMemExpr); 6669 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 6670 FoundDecl = MemExpr->getFoundDecl(); 6671 Qualifier = MemExpr->getQualifier(); 6672 } else { 6673 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 6674 Qualifier = UnresExpr->getQualifier(); 6675 6676 QualType ObjectType = UnresExpr->getBaseType(); 6677 6678 // Add overload candidates 6679 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc()); 6680 6681 // FIXME: avoid copy. 6682 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6683 if (UnresExpr->hasExplicitTemplateArgs()) { 6684 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6685 TemplateArgs = &TemplateArgsBuffer; 6686 } 6687 6688 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 6689 E = UnresExpr->decls_end(); I != E; ++I) { 6690 6691 NamedDecl *Func = *I; 6692 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 6693 if (isa<UsingShadowDecl>(Func)) 6694 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 6695 6696 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 6697 // If explicit template arguments were provided, we can't call a 6698 // non-template member function. 6699 if (TemplateArgs) 6700 continue; 6701 6702 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, 6703 Args, NumArgs, 6704 CandidateSet, /*SuppressUserConversions=*/false); 6705 } else { 6706 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 6707 I.getPair(), ActingDC, TemplateArgs, 6708 ObjectType, Args, NumArgs, 6709 CandidateSet, 6710 /*SuppressUsedConversions=*/false); 6711 } 6712 } 6713 6714 DeclarationName DeclName = UnresExpr->getMemberName(); 6715 6716 OverloadCandidateSet::iterator Best; 6717 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 6718 case OR_Success: 6719 Method = cast<CXXMethodDecl>(Best->Function); 6720 FoundDecl = Best->FoundDecl; 6721 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); 6722 DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()); 6723 break; 6724 6725 case OR_No_Viable_Function: 6726 Diag(UnresExpr->getMemberLoc(), 6727 diag::err_ovl_no_viable_member_function_in_call) 6728 << DeclName << MemExprE->getSourceRange(); 6729 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6730 // FIXME: Leaking incoming expressions! 6731 return ExprError(); 6732 6733 case OR_Ambiguous: 6734 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 6735 << DeclName << MemExprE->getSourceRange(); 6736 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6737 // FIXME: Leaking incoming expressions! 6738 return ExprError(); 6739 6740 case OR_Deleted: 6741 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 6742 << Best->Function->isDeleted() 6743 << DeclName << MemExprE->getSourceRange(); 6744 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6745 // FIXME: Leaking incoming expressions! 6746 return ExprError(); 6747 } 6748 6749 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); 6750 6751 // If overload resolution picked a static member, build a 6752 // non-member call based on that function. 6753 if (Method->isStatic()) { 6754 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 6755 Args, NumArgs, RParenLoc); 6756 } 6757 6758 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 6759 } 6760 6761 assert(Method && "Member call to something that isn't a method?"); 6762 ExprOwningPtr<CXXMemberCallExpr> 6763 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 6764 NumArgs, 6765 Method->getResultType().getNonReferenceType(), 6766 RParenLoc)); 6767 6768 // Check for a valid return type. 6769 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 6770 TheCall.get(), Method)) 6771 return ExprError(); 6772 6773 // Convert the object argument (for a non-static member function call). 6774 // We only need to do this if there was actually an overload; otherwise 6775 // it was done at lookup. 6776 Expr *ObjectArg = MemExpr->getBase(); 6777 if (!Method->isStatic() && 6778 PerformObjectArgumentInitialization(ObjectArg, Qualifier, 6779 FoundDecl, Method)) 6780 return ExprError(); 6781 MemExpr->setBase(ObjectArg); 6782 6783 // Convert the rest of the arguments 6784 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6785 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 6786 RParenLoc)) 6787 return ExprError(); 6788 6789 if (CheckFunctionCall(Method, TheCall.get())) 6790 return ExprError(); 6791 6792 return MaybeBindToTemporary(TheCall.release()); 6793} 6794 6795/// BuildCallToObjectOfClassType - Build a call to an object of class 6796/// type (C++ [over.call.object]), which can end up invoking an 6797/// overloaded function call operator (@c operator()) or performing a 6798/// user-defined conversion on the object argument. 6799Sema::ExprResult 6800Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 6801 SourceLocation LParenLoc, 6802 Expr **Args, unsigned NumArgs, 6803 SourceLocation *CommaLocs, 6804 SourceLocation RParenLoc) { 6805 assert(Object->getType()->isRecordType() && "Requires object type argument"); 6806 const RecordType *Record = Object->getType()->getAs<RecordType>(); 6807 6808 // C++ [over.call.object]p1: 6809 // If the primary-expression E in the function call syntax 6810 // evaluates to a class object of type "cv T", then the set of 6811 // candidate functions includes at least the function call 6812 // operators of T. The function call operators of T are obtained by 6813 // ordinary lookup of the name operator() in the context of 6814 // (E).operator(). 6815 OverloadCandidateSet CandidateSet(LParenLoc); 6816 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 6817 6818 if (RequireCompleteType(LParenLoc, Object->getType(), 6819 PDiag(diag::err_incomplete_object_call) 6820 << Object->getSourceRange())) 6821 return true; 6822 6823 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 6824 LookupQualifiedName(R, Record->getDecl()); 6825 R.suppressDiagnostics(); 6826 6827 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6828 Oper != OperEnd; ++Oper) { 6829 AddMethodCandidate(Oper.getPair(), Object->getType(), 6830 Args, NumArgs, CandidateSet, 6831 /*SuppressUserConversions=*/ false); 6832 } 6833 6834 // C++ [over.call.object]p2: 6835 // In addition, for each conversion function declared in T of the 6836 // form 6837 // 6838 // operator conversion-type-id () cv-qualifier; 6839 // 6840 // where cv-qualifier is the same cv-qualification as, or a 6841 // greater cv-qualification than, cv, and where conversion-type-id 6842 // denotes the type "pointer to function of (P1,...,Pn) returning 6843 // R", or the type "reference to pointer to function of 6844 // (P1,...,Pn) returning R", or the type "reference to function 6845 // of (P1,...,Pn) returning R", a surrogate call function [...] 6846 // is also considered as a candidate function. Similarly, 6847 // surrogate call functions are added to the set of candidate 6848 // functions for each conversion function declared in an 6849 // accessible base class provided the function is not hidden 6850 // within T by another intervening declaration. 6851 const UnresolvedSetImpl *Conversions 6852 = cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); 6853 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 6854 E = Conversions->end(); I != E; ++I) { 6855 NamedDecl *D = *I; 6856 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 6857 if (isa<UsingShadowDecl>(D)) 6858 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 6859 6860 // Skip over templated conversion functions; they aren't 6861 // surrogates. 6862 if (isa<FunctionTemplateDecl>(D)) 6863 continue; 6864 6865 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 6866 6867 // Strip the reference type (if any) and then the pointer type (if 6868 // any) to get down to what might be a function type. 6869 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 6870 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 6871 ConvType = ConvPtrType->getPointeeType(); 6872 6873 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 6874 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, 6875 Object->getType(), Args, NumArgs, 6876 CandidateSet); 6877 } 6878 6879 // Perform overload resolution. 6880 OverloadCandidateSet::iterator Best; 6881 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 6882 case OR_Success: 6883 // Overload resolution succeeded; we'll build the appropriate call 6884 // below. 6885 break; 6886 6887 case OR_No_Viable_Function: 6888 if (CandidateSet.empty()) 6889 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 6890 << Object->getType() << /*call*/ 1 6891 << Object->getSourceRange(); 6892 else 6893 Diag(Object->getSourceRange().getBegin(), 6894 diag::err_ovl_no_viable_object_call) 6895 << Object->getType() << Object->getSourceRange(); 6896 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6897 break; 6898 6899 case OR_Ambiguous: 6900 Diag(Object->getSourceRange().getBegin(), 6901 diag::err_ovl_ambiguous_object_call) 6902 << Object->getType() << Object->getSourceRange(); 6903 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6904 break; 6905 6906 case OR_Deleted: 6907 Diag(Object->getSourceRange().getBegin(), 6908 diag::err_ovl_deleted_object_call) 6909 << Best->Function->isDeleted() 6910 << Object->getType() << Object->getSourceRange(); 6911 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6912 break; 6913 } 6914 6915 if (Best == CandidateSet.end()) { 6916 // We had an error; delete all of the subexpressions and return 6917 // the error. 6918 Object->Destroy(Context); 6919 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6920 Args[ArgIdx]->Destroy(Context); 6921 return true; 6922 } 6923 6924 if (Best->Function == 0) { 6925 // Since there is no function declaration, this is one of the 6926 // surrogate candidates. Dig out the conversion function. 6927 CXXConversionDecl *Conv 6928 = cast<CXXConversionDecl>( 6929 Best->Conversions[0].UserDefined.ConversionFunction); 6930 6931 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6932 DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc); 6933 6934 // We selected one of the surrogate functions that converts the 6935 // object parameter to a function pointer. Perform the conversion 6936 // on the object argument, then let ActOnCallExpr finish the job. 6937 6938 // Create an implicit member expr to refer to the conversion operator. 6939 // and then call it. 6940 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Best->FoundDecl, 6941 Conv); 6942 6943 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 6944 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 6945 CommaLocs, RParenLoc).result(); 6946 } 6947 6948 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6949 DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc); 6950 6951 // We found an overloaded operator(). Build a CXXOperatorCallExpr 6952 // that calls this method, using Object for the implicit object 6953 // parameter and passing along the remaining arguments. 6954 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6955 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6956 6957 unsigned NumArgsInProto = Proto->getNumArgs(); 6958 unsigned NumArgsToCheck = NumArgs; 6959 6960 // Build the full argument list for the method call (the 6961 // implicit object parameter is placed at the beginning of the 6962 // list). 6963 Expr **MethodArgs; 6964 if (NumArgs < NumArgsInProto) { 6965 NumArgsToCheck = NumArgsInProto; 6966 MethodArgs = new Expr*[NumArgsInProto + 1]; 6967 } else { 6968 MethodArgs = new Expr*[NumArgs + 1]; 6969 } 6970 MethodArgs[0] = Object; 6971 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6972 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 6973 6974 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 6975 SourceLocation()); 6976 UsualUnaryConversions(NewFn); 6977 6978 // Once we've built TheCall, all of the expressions are properly 6979 // owned. 6980 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6981 ExprOwningPtr<CXXOperatorCallExpr> 6982 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 6983 MethodArgs, NumArgs + 1, 6984 ResultTy, RParenLoc)); 6985 delete [] MethodArgs; 6986 6987 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 6988 Method)) 6989 return true; 6990 6991 // We may have default arguments. If so, we need to allocate more 6992 // slots in the call for them. 6993 if (NumArgs < NumArgsInProto) 6994 TheCall->setNumArgs(Context, NumArgsInProto + 1); 6995 else if (NumArgs > NumArgsInProto) 6996 NumArgsToCheck = NumArgsInProto; 6997 6998 bool IsError = false; 6999 7000 // Initialize the implicit object parameter. 7001 IsError |= PerformObjectArgumentInitialization(Object, /*Qualifier=*/0, 7002 Best->FoundDecl, Method); 7003 TheCall->setArg(0, Object); 7004 7005 7006 // Check the argument types. 7007 for (unsigned i = 0; i != NumArgsToCheck; i++) { 7008 Expr *Arg; 7009 if (i < NumArgs) { 7010 Arg = Args[i]; 7011 7012 // Pass the argument. 7013 7014 OwningExprResult InputInit 7015 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 7016 Method->getParamDecl(i)), 7017 SourceLocation(), Owned(Arg)); 7018 7019 IsError |= InputInit.isInvalid(); 7020 Arg = InputInit.takeAs<Expr>(); 7021 } else { 7022 OwningExprResult DefArg 7023 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 7024 if (DefArg.isInvalid()) { 7025 IsError = true; 7026 break; 7027 } 7028 7029 Arg = DefArg.takeAs<Expr>(); 7030 } 7031 7032 TheCall->setArg(i + 1, Arg); 7033 } 7034 7035 // If this is a variadic call, handle args passed through "...". 7036 if (Proto->isVariadic()) { 7037 // Promote the arguments (C99 6.5.2.2p7). 7038 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 7039 Expr *Arg = Args[i]; 7040 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 7041 TheCall->setArg(i + 1, Arg); 7042 } 7043 } 7044 7045 if (IsError) return true; 7046 7047 if (CheckFunctionCall(Method, TheCall.get())) 7048 return true; 7049 7050 return MaybeBindToTemporary(TheCall.release()).result(); 7051} 7052 7053/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 7054/// (if one exists), where @c Base is an expression of class type and 7055/// @c Member is the name of the member we're trying to find. 7056Sema::OwningExprResult 7057Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 7058 Expr *Base = static_cast<Expr *>(BaseIn.get()); 7059 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 7060 7061 SourceLocation Loc = Base->getExprLoc(); 7062 7063 // C++ [over.ref]p1: 7064 // 7065 // [...] An expression x->m is interpreted as (x.operator->())->m 7066 // for a class object x of type T if T::operator->() exists and if 7067 // the operator is selected as the best match function by the 7068 // overload resolution mechanism (13.3). 7069 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 7070 OverloadCandidateSet CandidateSet(Loc); 7071 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 7072 7073 if (RequireCompleteType(Loc, Base->getType(), 7074 PDiag(diag::err_typecheck_incomplete_tag) 7075 << Base->getSourceRange())) 7076 return ExprError(); 7077 7078 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 7079 LookupQualifiedName(R, BaseRecord->getDecl()); 7080 R.suppressDiagnostics(); 7081 7082 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 7083 Oper != OperEnd; ++Oper) { 7084 AddMethodCandidate(Oper.getPair(), Base->getType(), 0, 0, CandidateSet, 7085 /*SuppressUserConversions=*/false); 7086 } 7087 7088 // Perform overload resolution. 7089 OverloadCandidateSet::iterator Best; 7090 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 7091 case OR_Success: 7092 // Overload resolution succeeded; we'll build the call below. 7093 break; 7094 7095 case OR_No_Viable_Function: 7096 if (CandidateSet.empty()) 7097 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 7098 << Base->getType() << Base->getSourceRange(); 7099 else 7100 Diag(OpLoc, diag::err_ovl_no_viable_oper) 7101 << "operator->" << Base->getSourceRange(); 7102 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 7103 return ExprError(); 7104 7105 case OR_Ambiguous: 7106 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 7107 << "->" << Base->getSourceRange(); 7108 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, &Base, 1); 7109 return ExprError(); 7110 7111 case OR_Deleted: 7112 Diag(OpLoc, diag::err_ovl_deleted_oper) 7113 << Best->Function->isDeleted() 7114 << "->" << Base->getSourceRange(); 7115 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 7116 return ExprError(); 7117 } 7118 7119 CheckMemberOperatorAccess(OpLoc, Base, 0, Best->FoundDecl); 7120 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 7121 7122 // Convert the object parameter. 7123 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 7124 if (PerformObjectArgumentInitialization(Base, /*Qualifier=*/0, 7125 Best->FoundDecl, Method)) 7126 return ExprError(); 7127 7128 // No concerns about early exits now. 7129 BaseIn.release(); 7130 7131 // Build the operator call. 7132 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 7133 SourceLocation()); 7134 UsualUnaryConversions(FnExpr); 7135 7136 QualType ResultTy = Method->getResultType().getNonReferenceType(); 7137 ExprOwningPtr<CXXOperatorCallExpr> 7138 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 7139 &Base, 1, ResultTy, OpLoc)); 7140 7141 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 7142 Method)) 7143 return ExprError(); 7144 return move(TheCall); 7145} 7146 7147/// FixOverloadedFunctionReference - E is an expression that refers to 7148/// a C++ overloaded function (possibly with some parentheses and 7149/// perhaps a '&' around it). We have resolved the overloaded function 7150/// to the function declaration Fn, so patch up the expression E to 7151/// refer (possibly indirectly) to Fn. Returns the new expr. 7152Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, 7153 FunctionDecl *Fn) { 7154 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 7155 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), 7156 Found, Fn); 7157 if (SubExpr == PE->getSubExpr()) 7158 return PE->Retain(); 7159 7160 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 7161 } 7162 7163 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 7164 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), 7165 Found, Fn); 7166 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 7167 SubExpr->getType()) && 7168 "Implicit cast type cannot be determined from overload"); 7169 if (SubExpr == ICE->getSubExpr()) 7170 return ICE->Retain(); 7171 7172 return new (Context) ImplicitCastExpr(ICE->getType(), 7173 ICE->getCastKind(), 7174 SubExpr, CXXBaseSpecifierArray(), 7175 ICE->isLvalueCast()); 7176 } 7177 7178 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 7179 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 7180 "Can only take the address of an overloaded function"); 7181 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 7182 if (Method->isStatic()) { 7183 // Do nothing: static member functions aren't any different 7184 // from non-member functions. 7185 } else { 7186 // Fix the sub expression, which really has to be an 7187 // UnresolvedLookupExpr holding an overloaded member function 7188 // or template. 7189 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 7190 Found, Fn); 7191 if (SubExpr == UnOp->getSubExpr()) 7192 return UnOp->Retain(); 7193 7194 assert(isa<DeclRefExpr>(SubExpr) 7195 && "fixed to something other than a decl ref"); 7196 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 7197 && "fixed to a member ref with no nested name qualifier"); 7198 7199 // We have taken the address of a pointer to member 7200 // function. Perform the computation here so that we get the 7201 // appropriate pointer to member type. 7202 QualType ClassType 7203 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 7204 QualType MemPtrType 7205 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 7206 7207 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 7208 MemPtrType, UnOp->getOperatorLoc()); 7209 } 7210 } 7211 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 7212 Found, Fn); 7213 if (SubExpr == UnOp->getSubExpr()) 7214 return UnOp->Retain(); 7215 7216 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 7217 Context.getPointerType(SubExpr->getType()), 7218 UnOp->getOperatorLoc()); 7219 } 7220 7221 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 7222 // FIXME: avoid copy. 7223 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 7224 if (ULE->hasExplicitTemplateArgs()) { 7225 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 7226 TemplateArgs = &TemplateArgsBuffer; 7227 } 7228 7229 return DeclRefExpr::Create(Context, 7230 ULE->getQualifier(), 7231 ULE->getQualifierRange(), 7232 Fn, 7233 ULE->getNameLoc(), 7234 Fn->getType(), 7235 TemplateArgs); 7236 } 7237 7238 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 7239 // FIXME: avoid copy. 7240 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 7241 if (MemExpr->hasExplicitTemplateArgs()) { 7242 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 7243 TemplateArgs = &TemplateArgsBuffer; 7244 } 7245 7246 Expr *Base; 7247 7248 // If we're filling in 7249 if (MemExpr->isImplicitAccess()) { 7250 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 7251 return DeclRefExpr::Create(Context, 7252 MemExpr->getQualifier(), 7253 MemExpr->getQualifierRange(), 7254 Fn, 7255 MemExpr->getMemberLoc(), 7256 Fn->getType(), 7257 TemplateArgs); 7258 } else { 7259 SourceLocation Loc = MemExpr->getMemberLoc(); 7260 if (MemExpr->getQualifier()) 7261 Loc = MemExpr->getQualifierRange().getBegin(); 7262 Base = new (Context) CXXThisExpr(Loc, 7263 MemExpr->getBaseType(), 7264 /*isImplicit=*/true); 7265 } 7266 } else 7267 Base = MemExpr->getBase()->Retain(); 7268 7269 return MemberExpr::Create(Context, Base, 7270 MemExpr->isArrow(), 7271 MemExpr->getQualifier(), 7272 MemExpr->getQualifierRange(), 7273 Fn, 7274 Found, 7275 MemExpr->getMemberLoc(), 7276 TemplateArgs, 7277 Fn->getType()); 7278 } 7279 7280 assert(false && "Invalid reference to overloaded function"); 7281 return E->Retain(); 7282} 7283 7284Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 7285 DeclAccessPair Found, 7286 FunctionDecl *Fn) { 7287 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Found, Fn)); 7288} 7289 7290} // end namespace clang 7291