SemaOverload.cpp revision aaa045dbe74366f9dba334fd01c797087898c1cc
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 return TryImplicitConversion(From, Context.BoolTy, 2914 // FIXME: Are these flags correct? 2915 /*SuppressUserConversions=*/false, 2916 /*AllowExplicit=*/true, 2917 /*InOverloadResolution=*/false); 2918} 2919 2920/// PerformContextuallyConvertToBool - Perform a contextual conversion 2921/// of the expression From to bool (C++0x [conv]p3). 2922bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2923 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2924 if (!ICS.isBad()) 2925 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); 2926 2927 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2928 return Diag(From->getSourceRange().getBegin(), 2929 diag::err_typecheck_bool_condition) 2930 << From->getType() << From->getSourceRange(); 2931 return true; 2932} 2933 2934/// AddOverloadCandidate - Adds the given function to the set of 2935/// candidate functions, using the given function call arguments. If 2936/// @p SuppressUserConversions, then don't allow user-defined 2937/// conversions via constructors or conversion operators. 2938/// 2939/// \para PartialOverloading true if we are performing "partial" overloading 2940/// based on an incomplete set of function arguments. This feature is used by 2941/// code completion. 2942void 2943Sema::AddOverloadCandidate(FunctionDecl *Function, 2944 DeclAccessPair FoundDecl, 2945 Expr **Args, unsigned NumArgs, 2946 OverloadCandidateSet& CandidateSet, 2947 bool SuppressUserConversions, 2948 bool PartialOverloading) { 2949 const FunctionProtoType* Proto 2950 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2951 assert(Proto && "Functions without a prototype cannot be overloaded"); 2952 assert(!Function->getDescribedFunctionTemplate() && 2953 "Use AddTemplateOverloadCandidate for function templates"); 2954 2955 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2956 if (!isa<CXXConstructorDecl>(Method)) { 2957 // If we get here, it's because we're calling a member function 2958 // that is named without a member access expression (e.g., 2959 // "this->f") that was either written explicitly or created 2960 // implicitly. This can happen with a qualified call to a member 2961 // function, e.g., X::f(). We use an empty type for the implied 2962 // object argument (C++ [over.call.func]p3), and the acting context 2963 // is irrelevant. 2964 AddMethodCandidate(Method, FoundDecl, Method->getParent(), 2965 QualType(), Args, NumArgs, CandidateSet, 2966 SuppressUserConversions); 2967 return; 2968 } 2969 // We treat a constructor like a non-member function, since its object 2970 // argument doesn't participate in overload resolution. 2971 } 2972 2973 if (!CandidateSet.isNewCandidate(Function)) 2974 return; 2975 2976 // Overload resolution is always an unevaluated context. 2977 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2978 2979 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2980 // C++ [class.copy]p3: 2981 // A member function template is never instantiated to perform the copy 2982 // of a class object to an object of its class type. 2983 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2984 if (NumArgs == 1 && 2985 Constructor->isCopyConstructorLikeSpecialization() && 2986 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || 2987 IsDerivedFrom(Args[0]->getType(), ClassType))) 2988 return; 2989 } 2990 2991 // Add this candidate 2992 CandidateSet.push_back(OverloadCandidate()); 2993 OverloadCandidate& Candidate = CandidateSet.back(); 2994 Candidate.FoundDecl = FoundDecl; 2995 Candidate.Function = Function; 2996 Candidate.Viable = true; 2997 Candidate.IsSurrogate = false; 2998 Candidate.IgnoreObjectArgument = false; 2999 3000 unsigned NumArgsInProto = Proto->getNumArgs(); 3001 3002 // (C++ 13.3.2p2): A candidate function having fewer than m 3003 // parameters is viable only if it has an ellipsis in its parameter 3004 // list (8.3.5). 3005 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 3006 !Proto->isVariadic()) { 3007 Candidate.Viable = false; 3008 Candidate.FailureKind = ovl_fail_too_many_arguments; 3009 return; 3010 } 3011 3012 // (C++ 13.3.2p2): A candidate function having more than m parameters 3013 // is viable only if the (m+1)st parameter has a default argument 3014 // (8.3.6). For the purposes of overload resolution, the 3015 // parameter list is truncated on the right, so that there are 3016 // exactly m parameters. 3017 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 3018 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 3019 // Not enough arguments. 3020 Candidate.Viable = false; 3021 Candidate.FailureKind = ovl_fail_too_few_arguments; 3022 return; 3023 } 3024 3025 // Determine the implicit conversion sequences for each of the 3026 // arguments. 3027 Candidate.Conversions.resize(NumArgs); 3028 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3029 if (ArgIdx < NumArgsInProto) { 3030 // (C++ 13.3.2p3): for F to be a viable function, there shall 3031 // exist for each argument an implicit conversion sequence 3032 // (13.3.3.1) that converts that argument to the corresponding 3033 // parameter of F. 3034 QualType ParamType = Proto->getArgType(ArgIdx); 3035 Candidate.Conversions[ArgIdx] 3036 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3037 SuppressUserConversions, 3038 /*InOverloadResolution=*/true); 3039 if (Candidate.Conversions[ArgIdx].isBad()) { 3040 Candidate.Viable = false; 3041 Candidate.FailureKind = ovl_fail_bad_conversion; 3042 break; 3043 } 3044 } else { 3045 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3046 // argument for which there is no corresponding parameter is 3047 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3048 Candidate.Conversions[ArgIdx].setEllipsis(); 3049 } 3050 } 3051} 3052 3053/// \brief Add all of the function declarations in the given function set to 3054/// the overload canddiate set. 3055void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, 3056 Expr **Args, unsigned NumArgs, 3057 OverloadCandidateSet& CandidateSet, 3058 bool SuppressUserConversions) { 3059 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { 3060 NamedDecl *D = F.getDecl()->getUnderlyingDecl(); 3061 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 3062 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 3063 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), 3064 cast<CXXMethodDecl>(FD)->getParent(), 3065 Args[0]->getType(), Args + 1, NumArgs - 1, 3066 CandidateSet, SuppressUserConversions); 3067 else 3068 AddOverloadCandidate(FD, F.getPair(), Args, NumArgs, CandidateSet, 3069 SuppressUserConversions); 3070 } else { 3071 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D); 3072 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 3073 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 3074 AddMethodTemplateCandidate(FunTmpl, F.getPair(), 3075 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 3076 /*FIXME: explicit args */ 0, 3077 Args[0]->getType(), Args + 1, NumArgs - 1, 3078 CandidateSet, 3079 SuppressUserConversions); 3080 else 3081 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), 3082 /*FIXME: explicit args */ 0, 3083 Args, NumArgs, CandidateSet, 3084 SuppressUserConversions); 3085 } 3086 } 3087} 3088 3089/// AddMethodCandidate - Adds a named decl (which is some kind of 3090/// method) as a method candidate to the given overload set. 3091void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, 3092 QualType ObjectType, 3093 Expr **Args, unsigned NumArgs, 3094 OverloadCandidateSet& CandidateSet, 3095 bool SuppressUserConversions) { 3096 NamedDecl *Decl = FoundDecl.getDecl(); 3097 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 3098 3099 if (isa<UsingShadowDecl>(Decl)) 3100 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 3101 3102 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 3103 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 3104 "Expected a member function template"); 3105 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, 3106 /*ExplicitArgs*/ 0, 3107 ObjectType, Args, NumArgs, 3108 CandidateSet, 3109 SuppressUserConversions); 3110 } else { 3111 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, 3112 ObjectType, Args, NumArgs, 3113 CandidateSet, SuppressUserConversions); 3114 } 3115} 3116 3117/// AddMethodCandidate - Adds the given C++ member function to the set 3118/// of candidate functions, using the given function call arguments 3119/// and the object argument (@c Object). For example, in a call 3120/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 3121/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 3122/// allow user-defined conversions via constructors or conversion 3123/// operators. 3124void 3125Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, 3126 CXXRecordDecl *ActingContext, QualType ObjectType, 3127 Expr **Args, unsigned NumArgs, 3128 OverloadCandidateSet& CandidateSet, 3129 bool SuppressUserConversions) { 3130 const FunctionProtoType* Proto 3131 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 3132 assert(Proto && "Methods without a prototype cannot be overloaded"); 3133 assert(!isa<CXXConstructorDecl>(Method) && 3134 "Use AddOverloadCandidate for constructors"); 3135 3136 if (!CandidateSet.isNewCandidate(Method)) 3137 return; 3138 3139 // Overload resolution is always an unevaluated context. 3140 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3141 3142 // Add this candidate 3143 CandidateSet.push_back(OverloadCandidate()); 3144 OverloadCandidate& Candidate = CandidateSet.back(); 3145 Candidate.FoundDecl = FoundDecl; 3146 Candidate.Function = Method; 3147 Candidate.IsSurrogate = false; 3148 Candidate.IgnoreObjectArgument = false; 3149 3150 unsigned NumArgsInProto = Proto->getNumArgs(); 3151 3152 // (C++ 13.3.2p2): A candidate function having fewer than m 3153 // parameters is viable only if it has an ellipsis in its parameter 3154 // list (8.3.5). 3155 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3156 Candidate.Viable = false; 3157 Candidate.FailureKind = ovl_fail_too_many_arguments; 3158 return; 3159 } 3160 3161 // (C++ 13.3.2p2): A candidate function having more than m parameters 3162 // is viable only if the (m+1)st parameter has a default argument 3163 // (8.3.6). For the purposes of overload resolution, the 3164 // parameter list is truncated on the right, so that there are 3165 // exactly m parameters. 3166 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 3167 if (NumArgs < MinRequiredArgs) { 3168 // Not enough arguments. 3169 Candidate.Viable = false; 3170 Candidate.FailureKind = ovl_fail_too_few_arguments; 3171 return; 3172 } 3173 3174 Candidate.Viable = true; 3175 Candidate.Conversions.resize(NumArgs + 1); 3176 3177 if (Method->isStatic() || ObjectType.isNull()) 3178 // The implicit object argument is ignored. 3179 Candidate.IgnoreObjectArgument = true; 3180 else { 3181 // Determine the implicit conversion sequence for the object 3182 // parameter. 3183 Candidate.Conversions[0] 3184 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 3185 if (Candidate.Conversions[0].isBad()) { 3186 Candidate.Viable = false; 3187 Candidate.FailureKind = ovl_fail_bad_conversion; 3188 return; 3189 } 3190 } 3191 3192 // Determine the implicit conversion sequences for each of the 3193 // arguments. 3194 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3195 if (ArgIdx < NumArgsInProto) { 3196 // (C++ 13.3.2p3): for F to be a viable function, there shall 3197 // exist for each argument an implicit conversion sequence 3198 // (13.3.3.1) that converts that argument to the corresponding 3199 // parameter of F. 3200 QualType ParamType = Proto->getArgType(ArgIdx); 3201 Candidate.Conversions[ArgIdx + 1] 3202 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3203 SuppressUserConversions, 3204 /*InOverloadResolution=*/true); 3205 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3206 Candidate.Viable = false; 3207 Candidate.FailureKind = ovl_fail_bad_conversion; 3208 break; 3209 } 3210 } else { 3211 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3212 // argument for which there is no corresponding parameter is 3213 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3214 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3215 } 3216 } 3217} 3218 3219/// \brief Add a C++ member function template as a candidate to the candidate 3220/// set, using template argument deduction to produce an appropriate member 3221/// function template specialization. 3222void 3223Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 3224 DeclAccessPair FoundDecl, 3225 CXXRecordDecl *ActingContext, 3226 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3227 QualType ObjectType, 3228 Expr **Args, unsigned NumArgs, 3229 OverloadCandidateSet& CandidateSet, 3230 bool SuppressUserConversions) { 3231 if (!CandidateSet.isNewCandidate(MethodTmpl)) 3232 return; 3233 3234 // C++ [over.match.funcs]p7: 3235 // In each case where a candidate is a function template, candidate 3236 // function template specializations are generated using template argument 3237 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3238 // candidate functions in the usual way.113) A given name can refer to one 3239 // or more function templates and also to a set of overloaded non-template 3240 // functions. In such a case, the candidate functions generated from each 3241 // function template are combined with the set of non-template candidate 3242 // functions. 3243 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3244 FunctionDecl *Specialization = 0; 3245 if (TemplateDeductionResult Result 3246 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 3247 Args, NumArgs, Specialization, Info)) { 3248 CandidateSet.push_back(OverloadCandidate()); 3249 OverloadCandidate &Candidate = CandidateSet.back(); 3250 Candidate.FoundDecl = FoundDecl; 3251 Candidate.Function = MethodTmpl->getTemplatedDecl(); 3252 Candidate.Viable = false; 3253 Candidate.FailureKind = ovl_fail_bad_deduction; 3254 Candidate.IsSurrogate = false; 3255 Candidate.IgnoreObjectArgument = false; 3256 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3257 Info); 3258 return; 3259 } 3260 3261 // Add the function template specialization produced by template argument 3262 // deduction as a candidate. 3263 assert(Specialization && "Missing member function template specialization?"); 3264 assert(isa<CXXMethodDecl>(Specialization) && 3265 "Specialization is not a member function?"); 3266 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl, 3267 ActingContext, ObjectType, Args, NumArgs, 3268 CandidateSet, SuppressUserConversions); 3269} 3270 3271/// \brief Add a C++ function template specialization as a candidate 3272/// in the candidate set, using template argument deduction to produce 3273/// an appropriate function template specialization. 3274void 3275Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 3276 DeclAccessPair FoundDecl, 3277 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3278 Expr **Args, unsigned NumArgs, 3279 OverloadCandidateSet& CandidateSet, 3280 bool SuppressUserConversions) { 3281 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3282 return; 3283 3284 // C++ [over.match.funcs]p7: 3285 // In each case where a candidate is a function template, candidate 3286 // function template specializations are generated using template argument 3287 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3288 // candidate functions in the usual way.113) A given name can refer to one 3289 // or more function templates and also to a set of overloaded non-template 3290 // functions. In such a case, the candidate functions generated from each 3291 // function template are combined with the set of non-template candidate 3292 // functions. 3293 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3294 FunctionDecl *Specialization = 0; 3295 if (TemplateDeductionResult Result 3296 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3297 Args, NumArgs, Specialization, Info)) { 3298 CandidateSet.push_back(OverloadCandidate()); 3299 OverloadCandidate &Candidate = CandidateSet.back(); 3300 Candidate.FoundDecl = FoundDecl; 3301 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3302 Candidate.Viable = false; 3303 Candidate.FailureKind = ovl_fail_bad_deduction; 3304 Candidate.IsSurrogate = false; 3305 Candidate.IgnoreObjectArgument = false; 3306 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3307 Info); 3308 return; 3309 } 3310 3311 // Add the function template specialization produced by template argument 3312 // deduction as a candidate. 3313 assert(Specialization && "Missing function template specialization?"); 3314 AddOverloadCandidate(Specialization, FoundDecl, Args, NumArgs, CandidateSet, 3315 SuppressUserConversions); 3316} 3317 3318/// AddConversionCandidate - Add a C++ conversion function as a 3319/// candidate in the candidate set (C++ [over.match.conv], 3320/// C++ [over.match.copy]). From is the expression we're converting from, 3321/// and ToType is the type that we're eventually trying to convert to 3322/// (which may or may not be the same type as the type that the 3323/// conversion function produces). 3324void 3325Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 3326 DeclAccessPair FoundDecl, 3327 CXXRecordDecl *ActingContext, 3328 Expr *From, QualType ToType, 3329 OverloadCandidateSet& CandidateSet) { 3330 assert(!Conversion->getDescribedFunctionTemplate() && 3331 "Conversion function templates use AddTemplateConversionCandidate"); 3332 QualType ConvType = Conversion->getConversionType().getNonReferenceType(); 3333 if (!CandidateSet.isNewCandidate(Conversion)) 3334 return; 3335 3336 // Overload resolution is always an unevaluated context. 3337 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3338 3339 // Add this candidate 3340 CandidateSet.push_back(OverloadCandidate()); 3341 OverloadCandidate& Candidate = CandidateSet.back(); 3342 Candidate.FoundDecl = FoundDecl; 3343 Candidate.Function = Conversion; 3344 Candidate.IsSurrogate = false; 3345 Candidate.IgnoreObjectArgument = false; 3346 Candidate.FinalConversion.setAsIdentityConversion(); 3347 Candidate.FinalConversion.setFromType(ConvType); 3348 Candidate.FinalConversion.setAllToTypes(ToType); 3349 3350 // Determine the implicit conversion sequence for the implicit 3351 // object parameter. 3352 Candidate.Viable = true; 3353 Candidate.Conversions.resize(1); 3354 Candidate.Conversions[0] 3355 = TryObjectArgumentInitialization(From->getType(), Conversion, 3356 ActingContext); 3357 // Conversion functions to a different type in the base class is visible in 3358 // the derived class. So, a derived to base conversion should not participate 3359 // in overload resolution. 3360 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 3361 Candidate.Conversions[0].Standard.Second = ICK_Identity; 3362 if (Candidate.Conversions[0].isBad()) { 3363 Candidate.Viable = false; 3364 Candidate.FailureKind = ovl_fail_bad_conversion; 3365 return; 3366 } 3367 3368 // We won't go through a user-define type conversion function to convert a 3369 // derived to base as such conversions are given Conversion Rank. They only 3370 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 3371 QualType FromCanon 3372 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 3373 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 3374 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 3375 Candidate.Viable = false; 3376 Candidate.FailureKind = ovl_fail_trivial_conversion; 3377 return; 3378 } 3379 3380 // To determine what the conversion from the result of calling the 3381 // conversion function to the type we're eventually trying to 3382 // convert to (ToType), we need to synthesize a call to the 3383 // conversion function and attempt copy initialization from it. This 3384 // makes sure that we get the right semantics with respect to 3385 // lvalues/rvalues and the type. Fortunately, we can allocate this 3386 // call on the stack and we don't need its arguments to be 3387 // well-formed. 3388 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 3389 From->getLocStart()); 3390 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 3391 CastExpr::CK_FunctionToPointerDecay, 3392 &ConversionRef, CXXBaseSpecifierArray(), false); 3393 3394 // Note that it is safe to allocate CallExpr on the stack here because 3395 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 3396 // allocator). 3397 CallExpr Call(Context, &ConversionFn, 0, 0, 3398 Conversion->getConversionType().getNonReferenceType(), 3399 From->getLocStart()); 3400 ImplicitConversionSequence ICS = 3401 TryCopyInitialization(*this, &Call, ToType, 3402 /*SuppressUserConversions=*/true, 3403 /*InOverloadResolution=*/false); 3404 3405 switch (ICS.getKind()) { 3406 case ImplicitConversionSequence::StandardConversion: 3407 Candidate.FinalConversion = ICS.Standard; 3408 3409 // C++ [over.ics.user]p3: 3410 // If the user-defined conversion is specified by a specialization of a 3411 // conversion function template, the second standard conversion sequence 3412 // shall have exact match rank. 3413 if (Conversion->getPrimaryTemplate() && 3414 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { 3415 Candidate.Viable = false; 3416 Candidate.FailureKind = ovl_fail_final_conversion_not_exact; 3417 } 3418 3419 break; 3420 3421 case ImplicitConversionSequence::BadConversion: 3422 Candidate.Viable = false; 3423 Candidate.FailureKind = ovl_fail_bad_final_conversion; 3424 break; 3425 3426 default: 3427 assert(false && 3428 "Can only end up with a standard conversion sequence or failure"); 3429 } 3430} 3431 3432/// \brief Adds a conversion function template specialization 3433/// candidate to the overload set, using template argument deduction 3434/// to deduce the template arguments of the conversion function 3435/// template from the type that we are converting to (C++ 3436/// [temp.deduct.conv]). 3437void 3438Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 3439 DeclAccessPair FoundDecl, 3440 CXXRecordDecl *ActingDC, 3441 Expr *From, QualType ToType, 3442 OverloadCandidateSet &CandidateSet) { 3443 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 3444 "Only conversion function templates permitted here"); 3445 3446 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3447 return; 3448 3449 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3450 CXXConversionDecl *Specialization = 0; 3451 if (TemplateDeductionResult Result 3452 = DeduceTemplateArguments(FunctionTemplate, ToType, 3453 Specialization, Info)) { 3454 CandidateSet.push_back(OverloadCandidate()); 3455 OverloadCandidate &Candidate = CandidateSet.back(); 3456 Candidate.FoundDecl = FoundDecl; 3457 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3458 Candidate.Viable = false; 3459 Candidate.FailureKind = ovl_fail_bad_deduction; 3460 Candidate.IsSurrogate = false; 3461 Candidate.IgnoreObjectArgument = false; 3462 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result, 3463 Info); 3464 return; 3465 } 3466 3467 // Add the conversion function template specialization produced by 3468 // template argument deduction as a candidate. 3469 assert(Specialization && "Missing function template specialization?"); 3470 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, 3471 CandidateSet); 3472} 3473 3474/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 3475/// converts the given @c Object to a function pointer via the 3476/// conversion function @c Conversion, and then attempts to call it 3477/// with the given arguments (C++ [over.call.object]p2-4). Proto is 3478/// the type of function that we'll eventually be calling. 3479void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 3480 DeclAccessPair FoundDecl, 3481 CXXRecordDecl *ActingContext, 3482 const FunctionProtoType *Proto, 3483 QualType ObjectType, 3484 Expr **Args, unsigned NumArgs, 3485 OverloadCandidateSet& CandidateSet) { 3486 if (!CandidateSet.isNewCandidate(Conversion)) 3487 return; 3488 3489 // Overload resolution is always an unevaluated context. 3490 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3491 3492 CandidateSet.push_back(OverloadCandidate()); 3493 OverloadCandidate& Candidate = CandidateSet.back(); 3494 Candidate.FoundDecl = FoundDecl; 3495 Candidate.Function = 0; 3496 Candidate.Surrogate = Conversion; 3497 Candidate.Viable = true; 3498 Candidate.IsSurrogate = true; 3499 Candidate.IgnoreObjectArgument = false; 3500 Candidate.Conversions.resize(NumArgs + 1); 3501 3502 // Determine the implicit conversion sequence for the implicit 3503 // object parameter. 3504 ImplicitConversionSequence ObjectInit 3505 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 3506 if (ObjectInit.isBad()) { 3507 Candidate.Viable = false; 3508 Candidate.FailureKind = ovl_fail_bad_conversion; 3509 Candidate.Conversions[0] = ObjectInit; 3510 return; 3511 } 3512 3513 // The first conversion is actually a user-defined conversion whose 3514 // first conversion is ObjectInit's standard conversion (which is 3515 // effectively a reference binding). Record it as such. 3516 Candidate.Conversions[0].setUserDefined(); 3517 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 3518 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 3519 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 3520 Candidate.Conversions[0].UserDefined.After 3521 = Candidate.Conversions[0].UserDefined.Before; 3522 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 3523 3524 // Find the 3525 unsigned NumArgsInProto = Proto->getNumArgs(); 3526 3527 // (C++ 13.3.2p2): A candidate function having fewer than m 3528 // parameters is viable only if it has an ellipsis in its parameter 3529 // list (8.3.5). 3530 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3531 Candidate.Viable = false; 3532 Candidate.FailureKind = ovl_fail_too_many_arguments; 3533 return; 3534 } 3535 3536 // Function types don't have any default arguments, so just check if 3537 // we have enough arguments. 3538 if (NumArgs < NumArgsInProto) { 3539 // Not enough arguments. 3540 Candidate.Viable = false; 3541 Candidate.FailureKind = ovl_fail_too_few_arguments; 3542 return; 3543 } 3544 3545 // Determine the implicit conversion sequences for each of the 3546 // arguments. 3547 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3548 if (ArgIdx < NumArgsInProto) { 3549 // (C++ 13.3.2p3): for F to be a viable function, there shall 3550 // exist for each argument an implicit conversion sequence 3551 // (13.3.3.1) that converts that argument to the corresponding 3552 // parameter of F. 3553 QualType ParamType = Proto->getArgType(ArgIdx); 3554 Candidate.Conversions[ArgIdx + 1] 3555 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3556 /*SuppressUserConversions=*/false, 3557 /*InOverloadResolution=*/false); 3558 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3559 Candidate.Viable = false; 3560 Candidate.FailureKind = ovl_fail_bad_conversion; 3561 break; 3562 } 3563 } else { 3564 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3565 // argument for which there is no corresponding parameter is 3566 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3567 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3568 } 3569 } 3570} 3571 3572/// \brief Add overload candidates for overloaded operators that are 3573/// member functions. 3574/// 3575/// Add the overloaded operator candidates that are member functions 3576/// for the operator Op that was used in an operator expression such 3577/// as "x Op y". , Args/NumArgs provides the operator arguments, and 3578/// CandidateSet will store the added overload candidates. (C++ 3579/// [over.match.oper]). 3580void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 3581 SourceLocation OpLoc, 3582 Expr **Args, unsigned NumArgs, 3583 OverloadCandidateSet& CandidateSet, 3584 SourceRange OpRange) { 3585 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3586 3587 // C++ [over.match.oper]p3: 3588 // For a unary operator @ with an operand of a type whose 3589 // cv-unqualified version is T1, and for a binary operator @ with 3590 // a left operand of a type whose cv-unqualified version is T1 and 3591 // a right operand of a type whose cv-unqualified version is T2, 3592 // three sets of candidate functions, designated member 3593 // candidates, non-member candidates and built-in candidates, are 3594 // constructed as follows: 3595 QualType T1 = Args[0]->getType(); 3596 QualType T2; 3597 if (NumArgs > 1) 3598 T2 = Args[1]->getType(); 3599 3600 // -- If T1 is a class type, the set of member candidates is the 3601 // result of the qualified lookup of T1::operator@ 3602 // (13.3.1.1.1); otherwise, the set of member candidates is 3603 // empty. 3604 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 3605 // Complete the type if it can be completed. Otherwise, we're done. 3606 if (RequireCompleteType(OpLoc, T1, PDiag())) 3607 return; 3608 3609 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 3610 LookupQualifiedName(Operators, T1Rec->getDecl()); 3611 Operators.suppressDiagnostics(); 3612 3613 for (LookupResult::iterator Oper = Operators.begin(), 3614 OperEnd = Operators.end(); 3615 Oper != OperEnd; 3616 ++Oper) 3617 AddMethodCandidate(Oper.getPair(), Args[0]->getType(), 3618 Args + 1, NumArgs - 1, CandidateSet, 3619 /* SuppressUserConversions = */ false); 3620 } 3621} 3622 3623/// AddBuiltinCandidate - Add a candidate for a built-in 3624/// operator. ResultTy and ParamTys are the result and parameter types 3625/// of the built-in candidate, respectively. Args and NumArgs are the 3626/// arguments being passed to the candidate. IsAssignmentOperator 3627/// should be true when this built-in candidate is an assignment 3628/// operator. NumContextualBoolArguments is the number of arguments 3629/// (at the beginning of the argument list) that will be contextually 3630/// converted to bool. 3631void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3632 Expr **Args, unsigned NumArgs, 3633 OverloadCandidateSet& CandidateSet, 3634 bool IsAssignmentOperator, 3635 unsigned NumContextualBoolArguments) { 3636 // Overload resolution is always an unevaluated context. 3637 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3638 3639 // Add this candidate 3640 CandidateSet.push_back(OverloadCandidate()); 3641 OverloadCandidate& Candidate = CandidateSet.back(); 3642 Candidate.FoundDecl = DeclAccessPair::make(0, AS_none); 3643 Candidate.Function = 0; 3644 Candidate.IsSurrogate = false; 3645 Candidate.IgnoreObjectArgument = false; 3646 Candidate.BuiltinTypes.ResultTy = ResultTy; 3647 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3648 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3649 3650 // Determine the implicit conversion sequences for each of the 3651 // arguments. 3652 Candidate.Viable = true; 3653 Candidate.Conversions.resize(NumArgs); 3654 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3655 // C++ [over.match.oper]p4: 3656 // For the built-in assignment operators, conversions of the 3657 // left operand are restricted as follows: 3658 // -- no temporaries are introduced to hold the left operand, and 3659 // -- no user-defined conversions are applied to the left 3660 // operand to achieve a type match with the left-most 3661 // parameter of a built-in candidate. 3662 // 3663 // We block these conversions by turning off user-defined 3664 // conversions, since that is the only way that initialization of 3665 // a reference to a non-class type can occur from something that 3666 // is not of the same type. 3667 if (ArgIdx < NumContextualBoolArguments) { 3668 assert(ParamTys[ArgIdx] == Context.BoolTy && 3669 "Contextual conversion to bool requires bool type"); 3670 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3671 } else { 3672 Candidate.Conversions[ArgIdx] 3673 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], 3674 ArgIdx == 0 && IsAssignmentOperator, 3675 /*InOverloadResolution=*/false); 3676 } 3677 if (Candidate.Conversions[ArgIdx].isBad()) { 3678 Candidate.Viable = false; 3679 Candidate.FailureKind = ovl_fail_bad_conversion; 3680 break; 3681 } 3682 } 3683} 3684 3685/// BuiltinCandidateTypeSet - A set of types that will be used for the 3686/// candidate operator functions for built-in operators (C++ 3687/// [over.built]). The types are separated into pointer types and 3688/// enumeration types. 3689class BuiltinCandidateTypeSet { 3690 /// TypeSet - A set of types. 3691 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3692 3693 /// PointerTypes - The set of pointer types that will be used in the 3694 /// built-in candidates. 3695 TypeSet PointerTypes; 3696 3697 /// MemberPointerTypes - The set of member pointer types that will be 3698 /// used in the built-in candidates. 3699 TypeSet MemberPointerTypes; 3700 3701 /// EnumerationTypes - The set of enumeration types that will be 3702 /// used in the built-in candidates. 3703 TypeSet EnumerationTypes; 3704 3705 /// Sema - The semantic analysis instance where we are building the 3706 /// candidate type set. 3707 Sema &SemaRef; 3708 3709 /// Context - The AST context in which we will build the type sets. 3710 ASTContext &Context; 3711 3712 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3713 const Qualifiers &VisibleQuals); 3714 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3715 3716public: 3717 /// iterator - Iterates through the types that are part of the set. 3718 typedef TypeSet::iterator iterator; 3719 3720 BuiltinCandidateTypeSet(Sema &SemaRef) 3721 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3722 3723 void AddTypesConvertedFrom(QualType Ty, 3724 SourceLocation Loc, 3725 bool AllowUserConversions, 3726 bool AllowExplicitConversions, 3727 const Qualifiers &VisibleTypeConversionsQuals); 3728 3729 /// pointer_begin - First pointer type found; 3730 iterator pointer_begin() { return PointerTypes.begin(); } 3731 3732 /// pointer_end - Past the last pointer type found; 3733 iterator pointer_end() { return PointerTypes.end(); } 3734 3735 /// member_pointer_begin - First member pointer type found; 3736 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3737 3738 /// member_pointer_end - Past the last member pointer type found; 3739 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3740 3741 /// enumeration_begin - First enumeration type found; 3742 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3743 3744 /// enumeration_end - Past the last enumeration type found; 3745 iterator enumeration_end() { return EnumerationTypes.end(); } 3746}; 3747 3748/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3749/// the set of pointer types along with any more-qualified variants of 3750/// that type. For example, if @p Ty is "int const *", this routine 3751/// will add "int const *", "int const volatile *", "int const 3752/// restrict *", and "int const volatile restrict *" to the set of 3753/// pointer types. Returns true if the add of @p Ty itself succeeded, 3754/// false otherwise. 3755/// 3756/// FIXME: what to do about extended qualifiers? 3757bool 3758BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3759 const Qualifiers &VisibleQuals) { 3760 3761 // Insert this type. 3762 if (!PointerTypes.insert(Ty)) 3763 return false; 3764 3765 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3766 assert(PointerTy && "type was not a pointer type!"); 3767 3768 QualType PointeeTy = PointerTy->getPointeeType(); 3769 // Don't add qualified variants of arrays. For one, they're not allowed 3770 // (the qualifier would sink to the element type), and for another, the 3771 // only overload situation where it matters is subscript or pointer +- int, 3772 // and those shouldn't have qualifier variants anyway. 3773 if (PointeeTy->isArrayType()) 3774 return true; 3775 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3776 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3777 BaseCVR = Array->getElementType().getCVRQualifiers(); 3778 bool hasVolatile = VisibleQuals.hasVolatile(); 3779 bool hasRestrict = VisibleQuals.hasRestrict(); 3780 3781 // Iterate through all strict supersets of BaseCVR. 3782 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3783 if ((CVR | BaseCVR) != CVR) continue; 3784 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3785 // in the types. 3786 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3787 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3788 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3789 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3790 } 3791 3792 return true; 3793} 3794 3795/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3796/// to the set of pointer types along with any more-qualified variants of 3797/// that type. For example, if @p Ty is "int const *", this routine 3798/// will add "int const *", "int const volatile *", "int const 3799/// restrict *", and "int const volatile restrict *" to the set of 3800/// pointer types. Returns true if the add of @p Ty itself succeeded, 3801/// false otherwise. 3802/// 3803/// FIXME: what to do about extended qualifiers? 3804bool 3805BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3806 QualType Ty) { 3807 // Insert this type. 3808 if (!MemberPointerTypes.insert(Ty)) 3809 return false; 3810 3811 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3812 assert(PointerTy && "type was not a member pointer type!"); 3813 3814 QualType PointeeTy = PointerTy->getPointeeType(); 3815 // Don't add qualified variants of arrays. For one, they're not allowed 3816 // (the qualifier would sink to the element type), and for another, the 3817 // only overload situation where it matters is subscript or pointer +- int, 3818 // and those shouldn't have qualifier variants anyway. 3819 if (PointeeTy->isArrayType()) 3820 return true; 3821 const Type *ClassTy = PointerTy->getClass(); 3822 3823 // Iterate through all strict supersets of the pointee type's CVR 3824 // qualifiers. 3825 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3826 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3827 if ((CVR | BaseCVR) != CVR) continue; 3828 3829 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3830 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3831 } 3832 3833 return true; 3834} 3835 3836/// AddTypesConvertedFrom - Add each of the types to which the type @p 3837/// Ty can be implicit converted to the given set of @p Types. We're 3838/// primarily interested in pointer types and enumeration types. We also 3839/// take member pointer types, for the conditional operator. 3840/// AllowUserConversions is true if we should look at the conversion 3841/// functions of a class type, and AllowExplicitConversions if we 3842/// should also include the explicit conversion functions of a class 3843/// type. 3844void 3845BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3846 SourceLocation Loc, 3847 bool AllowUserConversions, 3848 bool AllowExplicitConversions, 3849 const Qualifiers &VisibleQuals) { 3850 // Only deal with canonical types. 3851 Ty = Context.getCanonicalType(Ty); 3852 3853 // Look through reference types; they aren't part of the type of an 3854 // expression for the purposes of conversions. 3855 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3856 Ty = RefTy->getPointeeType(); 3857 3858 // We don't care about qualifiers on the type. 3859 Ty = Ty.getLocalUnqualifiedType(); 3860 3861 // If we're dealing with an array type, decay to the pointer. 3862 if (Ty->isArrayType()) 3863 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3864 3865 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3866 QualType PointeeTy = PointerTy->getPointeeType(); 3867 3868 // Insert our type, and its more-qualified variants, into the set 3869 // of types. 3870 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3871 return; 3872 } else if (Ty->isMemberPointerType()) { 3873 // Member pointers are far easier, since the pointee can't be converted. 3874 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3875 return; 3876 } else if (Ty->isEnumeralType()) { 3877 EnumerationTypes.insert(Ty); 3878 } else if (AllowUserConversions) { 3879 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3880 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3881 // No conversion functions in incomplete types. 3882 return; 3883 } 3884 3885 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3886 const UnresolvedSetImpl *Conversions 3887 = ClassDecl->getVisibleConversionFunctions(); 3888 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3889 E = Conversions->end(); I != E; ++I) { 3890 NamedDecl *D = I.getDecl(); 3891 if (isa<UsingShadowDecl>(D)) 3892 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3893 3894 // Skip conversion function templates; they don't tell us anything 3895 // about which builtin types we can convert to. 3896 if (isa<FunctionTemplateDecl>(D)) 3897 continue; 3898 3899 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 3900 if (AllowExplicitConversions || !Conv->isExplicit()) { 3901 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3902 VisibleQuals); 3903 } 3904 } 3905 } 3906 } 3907} 3908 3909/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3910/// the volatile- and non-volatile-qualified assignment operators for the 3911/// given type to the candidate set. 3912static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3913 QualType T, 3914 Expr **Args, 3915 unsigned NumArgs, 3916 OverloadCandidateSet &CandidateSet) { 3917 QualType ParamTypes[2]; 3918 3919 // T& operator=(T&, T) 3920 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3921 ParamTypes[1] = T; 3922 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3923 /*IsAssignmentOperator=*/true); 3924 3925 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3926 // volatile T& operator=(volatile T&, T) 3927 ParamTypes[0] 3928 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3929 ParamTypes[1] = T; 3930 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3931 /*IsAssignmentOperator=*/true); 3932 } 3933} 3934 3935/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3936/// if any, found in visible type conversion functions found in ArgExpr's type. 3937static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3938 Qualifiers VRQuals; 3939 const RecordType *TyRec; 3940 if (const MemberPointerType *RHSMPType = 3941 ArgExpr->getType()->getAs<MemberPointerType>()) 3942 TyRec = RHSMPType->getClass()->getAs<RecordType>(); 3943 else 3944 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3945 if (!TyRec) { 3946 // Just to be safe, assume the worst case. 3947 VRQuals.addVolatile(); 3948 VRQuals.addRestrict(); 3949 return VRQuals; 3950 } 3951 3952 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3953 if (!ClassDecl->hasDefinition()) 3954 return VRQuals; 3955 3956 const UnresolvedSetImpl *Conversions = 3957 ClassDecl->getVisibleConversionFunctions(); 3958 3959 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3960 E = Conversions->end(); I != E; ++I) { 3961 NamedDecl *D = I.getDecl(); 3962 if (isa<UsingShadowDecl>(D)) 3963 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3964 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { 3965 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3966 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3967 CanTy = ResTypeRef->getPointeeType(); 3968 // Need to go down the pointer/mempointer chain and add qualifiers 3969 // as see them. 3970 bool done = false; 3971 while (!done) { 3972 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3973 CanTy = ResTypePtr->getPointeeType(); 3974 else if (const MemberPointerType *ResTypeMPtr = 3975 CanTy->getAs<MemberPointerType>()) 3976 CanTy = ResTypeMPtr->getPointeeType(); 3977 else 3978 done = true; 3979 if (CanTy.isVolatileQualified()) 3980 VRQuals.addVolatile(); 3981 if (CanTy.isRestrictQualified()) 3982 VRQuals.addRestrict(); 3983 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3984 return VRQuals; 3985 } 3986 } 3987 } 3988 return VRQuals; 3989} 3990 3991/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3992/// operator overloads to the candidate set (C++ [over.built]), based 3993/// on the operator @p Op and the arguments given. For example, if the 3994/// operator is a binary '+', this routine might add "int 3995/// operator+(int, int)" to cover integer addition. 3996void 3997Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3998 SourceLocation OpLoc, 3999 Expr **Args, unsigned NumArgs, 4000 OverloadCandidateSet& CandidateSet) { 4001 // The set of "promoted arithmetic types", which are the arithmetic 4002 // types are that preserved by promotion (C++ [over.built]p2). Note 4003 // that the first few of these types are the promoted integral 4004 // types; these types need to be first. 4005 // FIXME: What about complex? 4006 const unsigned FirstIntegralType = 0; 4007 const unsigned LastIntegralType = 13; 4008 const unsigned FirstPromotedIntegralType = 7, 4009 LastPromotedIntegralType = 13; 4010 const unsigned FirstPromotedArithmeticType = 7, 4011 LastPromotedArithmeticType = 16; 4012 const unsigned NumArithmeticTypes = 16; 4013 QualType ArithmeticTypes[NumArithmeticTypes] = { 4014 Context.BoolTy, Context.CharTy, Context.WCharTy, 4015// FIXME: Context.Char16Ty, Context.Char32Ty, 4016 Context.SignedCharTy, Context.ShortTy, 4017 Context.UnsignedCharTy, Context.UnsignedShortTy, 4018 Context.IntTy, Context.LongTy, Context.LongLongTy, 4019 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 4020 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 4021 }; 4022 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 4023 "Invalid first promoted integral type"); 4024 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 4025 == Context.UnsignedLongLongTy && 4026 "Invalid last promoted integral type"); 4027 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 4028 "Invalid first promoted arithmetic type"); 4029 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 4030 == Context.LongDoubleTy && 4031 "Invalid last promoted arithmetic type"); 4032 4033 // Find all of the types that the arguments can convert to, but only 4034 // if the operator we're looking at has built-in operator candidates 4035 // that make use of these types. 4036 Qualifiers VisibleTypeConversionsQuals; 4037 VisibleTypeConversionsQuals.addConst(); 4038 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4039 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 4040 4041 BuiltinCandidateTypeSet CandidateTypes(*this); 4042 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 4043 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 4044 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 4045 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 4046 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 4047 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 4048 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4049 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 4050 OpLoc, 4051 true, 4052 (Op == OO_Exclaim || 4053 Op == OO_AmpAmp || 4054 Op == OO_PipePipe), 4055 VisibleTypeConversionsQuals); 4056 } 4057 4058 bool isComparison = false; 4059 switch (Op) { 4060 case OO_None: 4061 case NUM_OVERLOADED_OPERATORS: 4062 assert(false && "Expected an overloaded operator"); 4063 break; 4064 4065 case OO_Star: // '*' is either unary or binary 4066 if (NumArgs == 1) 4067 goto UnaryStar; 4068 else 4069 goto BinaryStar; 4070 break; 4071 4072 case OO_Plus: // '+' is either unary or binary 4073 if (NumArgs == 1) 4074 goto UnaryPlus; 4075 else 4076 goto BinaryPlus; 4077 break; 4078 4079 case OO_Minus: // '-' is either unary or binary 4080 if (NumArgs == 1) 4081 goto UnaryMinus; 4082 else 4083 goto BinaryMinus; 4084 break; 4085 4086 case OO_Amp: // '&' is either unary or binary 4087 if (NumArgs == 1) 4088 goto UnaryAmp; 4089 else 4090 goto BinaryAmp; 4091 4092 case OO_PlusPlus: 4093 case OO_MinusMinus: 4094 // C++ [over.built]p3: 4095 // 4096 // For every pair (T, VQ), where T is an arithmetic type, and VQ 4097 // is either volatile or empty, there exist candidate operator 4098 // functions of the form 4099 // 4100 // VQ T& operator++(VQ T&); 4101 // T operator++(VQ T&, int); 4102 // 4103 // C++ [over.built]p4: 4104 // 4105 // For every pair (T, VQ), where T is an arithmetic type other 4106 // than bool, and VQ is either volatile or empty, there exist 4107 // candidate operator functions of the form 4108 // 4109 // VQ T& operator--(VQ T&); 4110 // T operator--(VQ T&, int); 4111 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 4112 Arith < NumArithmeticTypes; ++Arith) { 4113 QualType ArithTy = ArithmeticTypes[Arith]; 4114 QualType ParamTypes[2] 4115 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 4116 4117 // Non-volatile version. 4118 if (NumArgs == 1) 4119 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4120 else 4121 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 4122 // heuristic to reduce number of builtin candidates in the set. 4123 // Add volatile version only if there are conversions to a volatile type. 4124 if (VisibleTypeConversionsQuals.hasVolatile()) { 4125 // Volatile version 4126 ParamTypes[0] 4127 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 4128 if (NumArgs == 1) 4129 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4130 else 4131 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 4132 } 4133 } 4134 4135 // C++ [over.built]p5: 4136 // 4137 // For every pair (T, VQ), where T is a cv-qualified or 4138 // cv-unqualified object type, and VQ is either volatile or 4139 // empty, there exist candidate operator functions of the form 4140 // 4141 // T*VQ& operator++(T*VQ&); 4142 // T*VQ& operator--(T*VQ&); 4143 // T* operator++(T*VQ&, int); 4144 // T* operator--(T*VQ&, int); 4145 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4146 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4147 // Skip pointer types that aren't pointers to object types. 4148 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 4149 continue; 4150 4151 QualType ParamTypes[2] = { 4152 Context.getLValueReferenceType(*Ptr), Context.IntTy 4153 }; 4154 4155 // Without volatile 4156 if (NumArgs == 1) 4157 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4158 else 4159 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4160 4161 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4162 VisibleTypeConversionsQuals.hasVolatile()) { 4163 // With volatile 4164 ParamTypes[0] 4165 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4166 if (NumArgs == 1) 4167 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 4168 else 4169 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4170 } 4171 } 4172 break; 4173 4174 UnaryStar: 4175 // C++ [over.built]p6: 4176 // For every cv-qualified or cv-unqualified object type T, there 4177 // exist candidate operator functions of the form 4178 // 4179 // T& operator*(T*); 4180 // 4181 // C++ [over.built]p7: 4182 // For every function type T, there exist candidate operator 4183 // functions of the form 4184 // T& operator*(T*); 4185 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4186 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4187 QualType ParamTy = *Ptr; 4188 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 4189 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 4190 &ParamTy, Args, 1, CandidateSet); 4191 } 4192 break; 4193 4194 UnaryPlus: 4195 // C++ [over.built]p8: 4196 // For every type T, there exist candidate operator functions of 4197 // the form 4198 // 4199 // T* operator+(T*); 4200 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4201 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4202 QualType ParamTy = *Ptr; 4203 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 4204 } 4205 4206 // Fall through 4207 4208 UnaryMinus: 4209 // C++ [over.built]p9: 4210 // For every promoted arithmetic type T, there exist candidate 4211 // operator functions of the form 4212 // 4213 // T operator+(T); 4214 // T operator-(T); 4215 for (unsigned Arith = FirstPromotedArithmeticType; 4216 Arith < LastPromotedArithmeticType; ++Arith) { 4217 QualType ArithTy = ArithmeticTypes[Arith]; 4218 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 4219 } 4220 break; 4221 4222 case OO_Tilde: 4223 // C++ [over.built]p10: 4224 // For every promoted integral type T, there exist candidate 4225 // operator functions of the form 4226 // 4227 // T operator~(T); 4228 for (unsigned Int = FirstPromotedIntegralType; 4229 Int < LastPromotedIntegralType; ++Int) { 4230 QualType IntTy = ArithmeticTypes[Int]; 4231 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 4232 } 4233 break; 4234 4235 case OO_New: 4236 case OO_Delete: 4237 case OO_Array_New: 4238 case OO_Array_Delete: 4239 case OO_Call: 4240 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 4241 break; 4242 4243 case OO_Comma: 4244 UnaryAmp: 4245 case OO_Arrow: 4246 // C++ [over.match.oper]p3: 4247 // -- For the operator ',', the unary operator '&', or the 4248 // operator '->', the built-in candidates set is empty. 4249 break; 4250 4251 case OO_EqualEqual: 4252 case OO_ExclaimEqual: 4253 // C++ [over.match.oper]p16: 4254 // For every pointer to member type T, there exist candidate operator 4255 // functions of the form 4256 // 4257 // bool operator==(T,T); 4258 // bool operator!=(T,T); 4259 for (BuiltinCandidateTypeSet::iterator 4260 MemPtr = CandidateTypes.member_pointer_begin(), 4261 MemPtrEnd = CandidateTypes.member_pointer_end(); 4262 MemPtr != MemPtrEnd; 4263 ++MemPtr) { 4264 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 4265 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4266 } 4267 4268 // Fall through 4269 4270 case OO_Less: 4271 case OO_Greater: 4272 case OO_LessEqual: 4273 case OO_GreaterEqual: 4274 // C++ [over.built]p15: 4275 // 4276 // For every pointer or enumeration type T, there exist 4277 // candidate operator functions of the form 4278 // 4279 // bool operator<(T, T); 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 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4286 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4287 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4288 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4289 } 4290 for (BuiltinCandidateTypeSet::iterator Enum 4291 = CandidateTypes.enumeration_begin(); 4292 Enum != CandidateTypes.enumeration_end(); ++Enum) { 4293 QualType ParamTypes[2] = { *Enum, *Enum }; 4294 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4295 } 4296 4297 // Fall through. 4298 isComparison = true; 4299 4300 BinaryPlus: 4301 BinaryMinus: 4302 if (!isComparison) { 4303 // We didn't fall through, so we must have OO_Plus or OO_Minus. 4304 4305 // C++ [over.built]p13: 4306 // 4307 // For every cv-qualified or cv-unqualified object type T 4308 // there exist candidate operator functions of the form 4309 // 4310 // T* operator+(T*, ptrdiff_t); 4311 // T& operator[](T*, ptrdiff_t); [BELOW] 4312 // T* operator-(T*, ptrdiff_t); 4313 // T* operator+(ptrdiff_t, T*); 4314 // T& operator[](ptrdiff_t, T*); [BELOW] 4315 // 4316 // C++ [over.built]p14: 4317 // 4318 // For every T, where T is a pointer to object type, there 4319 // exist candidate operator functions of the form 4320 // 4321 // ptrdiff_t operator-(T, T); 4322 for (BuiltinCandidateTypeSet::iterator Ptr 4323 = CandidateTypes.pointer_begin(); 4324 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4325 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4326 4327 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 4328 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4329 4330 if (Op == OO_Plus) { 4331 // T* operator+(ptrdiff_t, T*); 4332 ParamTypes[0] = ParamTypes[1]; 4333 ParamTypes[1] = *Ptr; 4334 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4335 } else { 4336 // ptrdiff_t operator-(T, T); 4337 ParamTypes[1] = *Ptr; 4338 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 4339 Args, 2, CandidateSet); 4340 } 4341 } 4342 } 4343 // Fall through 4344 4345 case OO_Slash: 4346 BinaryStar: 4347 Conditional: 4348 // C++ [over.built]p12: 4349 // 4350 // For every pair of promoted arithmetic types L and R, there 4351 // exist candidate operator functions of the form 4352 // 4353 // LR operator*(L, R); 4354 // LR operator/(L, R); 4355 // LR operator+(L, R); 4356 // LR operator-(L, R); 4357 // bool 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 // 4364 // where LR is the result of the usual arithmetic conversions 4365 // between types L and R. 4366 // 4367 // C++ [over.built]p24: 4368 // 4369 // For every pair of promoted arithmetic types L and R, there exist 4370 // candidate operator functions of the form 4371 // 4372 // LR operator?(bool, L, R); 4373 // 4374 // where LR is the result of the usual arithmetic conversions 4375 // between types L and R. 4376 // Our candidates ignore the first parameter. 4377 for (unsigned Left = FirstPromotedArithmeticType; 4378 Left < LastPromotedArithmeticType; ++Left) { 4379 for (unsigned Right = FirstPromotedArithmeticType; 4380 Right < LastPromotedArithmeticType; ++Right) { 4381 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4382 QualType Result 4383 = isComparison 4384 ? Context.BoolTy 4385 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4386 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4387 } 4388 } 4389 break; 4390 4391 case OO_Percent: 4392 BinaryAmp: 4393 case OO_Caret: 4394 case OO_Pipe: 4395 case OO_LessLess: 4396 case OO_GreaterGreater: 4397 // C++ [over.built]p17: 4398 // 4399 // For every pair of promoted integral types L and R, there 4400 // exist candidate operator functions of the form 4401 // 4402 // LR operator%(L, R); 4403 // LR operator&(L, R); 4404 // LR operator^(L, R); 4405 // LR operator|(L, R); 4406 // L operator<<(L, R); 4407 // L operator>>(L, R); 4408 // 4409 // where LR is the result of the usual arithmetic conversions 4410 // between types L and R. 4411 for (unsigned Left = FirstPromotedIntegralType; 4412 Left < LastPromotedIntegralType; ++Left) { 4413 for (unsigned Right = FirstPromotedIntegralType; 4414 Right < LastPromotedIntegralType; ++Right) { 4415 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4416 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 4417 ? LandR[0] 4418 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4419 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4420 } 4421 } 4422 break; 4423 4424 case OO_Equal: 4425 // C++ [over.built]p20: 4426 // 4427 // For every pair (T, VQ), where T is an enumeration or 4428 // pointer to member type and VQ is either volatile or 4429 // empty, there exist candidate operator functions of the form 4430 // 4431 // VQ T& operator=(VQ T&, T); 4432 for (BuiltinCandidateTypeSet::iterator 4433 Enum = CandidateTypes.enumeration_begin(), 4434 EnumEnd = CandidateTypes.enumeration_end(); 4435 Enum != EnumEnd; ++Enum) 4436 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 4437 CandidateSet); 4438 for (BuiltinCandidateTypeSet::iterator 4439 MemPtr = CandidateTypes.member_pointer_begin(), 4440 MemPtrEnd = CandidateTypes.member_pointer_end(); 4441 MemPtr != MemPtrEnd; ++MemPtr) 4442 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 4443 CandidateSet); 4444 // Fall through. 4445 4446 case OO_PlusEqual: 4447 case OO_MinusEqual: 4448 // C++ [over.built]p19: 4449 // 4450 // For every pair (T, VQ), where T is any type and VQ is either 4451 // volatile or empty, there exist candidate operator functions 4452 // of the form 4453 // 4454 // T*VQ& operator=(T*VQ&, T*); 4455 // 4456 // C++ [over.built]p21: 4457 // 4458 // For every pair (T, VQ), where T is a cv-qualified or 4459 // cv-unqualified object type and VQ is either volatile or 4460 // empty, there exist candidate operator functions of the form 4461 // 4462 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 4463 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 4464 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4465 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4466 QualType ParamTypes[2]; 4467 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 4468 4469 // non-volatile version 4470 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 4471 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4472 /*IsAssigmentOperator=*/Op == OO_Equal); 4473 4474 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4475 VisibleTypeConversionsQuals.hasVolatile()) { 4476 // volatile version 4477 ParamTypes[0] 4478 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4479 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4480 /*IsAssigmentOperator=*/Op == OO_Equal); 4481 } 4482 } 4483 // Fall through. 4484 4485 case OO_StarEqual: 4486 case OO_SlashEqual: 4487 // C++ [over.built]p18: 4488 // 4489 // For every triple (L, VQ, R), where L is an arithmetic type, 4490 // VQ is either volatile or empty, and R is a promoted 4491 // arithmetic type, there exist candidate operator functions of 4492 // the form 4493 // 4494 // VQ L& operator=(VQ L&, R); 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 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 4500 for (unsigned Right = FirstPromotedArithmeticType; 4501 Right < LastPromotedArithmeticType; ++Right) { 4502 QualType ParamTypes[2]; 4503 ParamTypes[1] = ArithmeticTypes[Right]; 4504 4505 // Add this built-in operator as a candidate (VQ is empty). 4506 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4507 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4508 /*IsAssigmentOperator=*/Op == OO_Equal); 4509 4510 // Add this built-in operator as a candidate (VQ is 'volatile'). 4511 if (VisibleTypeConversionsQuals.hasVolatile()) { 4512 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 4513 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4514 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4515 /*IsAssigmentOperator=*/Op == OO_Equal); 4516 } 4517 } 4518 } 4519 break; 4520 4521 case OO_PercentEqual: 4522 case OO_LessLessEqual: 4523 case OO_GreaterGreaterEqual: 4524 case OO_AmpEqual: 4525 case OO_CaretEqual: 4526 case OO_PipeEqual: 4527 // C++ [over.built]p22: 4528 // 4529 // For every triple (L, VQ, R), where L is an integral type, VQ 4530 // is either volatile or empty, and R is a promoted integral 4531 // type, there exist candidate operator functions of the form 4532 // 4533 // VQ L& operator%=(VQ L&, R); 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 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 4540 for (unsigned Right = FirstPromotedIntegralType; 4541 Right < LastPromotedIntegralType; ++Right) { 4542 QualType ParamTypes[2]; 4543 ParamTypes[1] = ArithmeticTypes[Right]; 4544 4545 // Add this built-in operator as a candidate (VQ is empty). 4546 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4547 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4548 if (VisibleTypeConversionsQuals.hasVolatile()) { 4549 // Add this built-in operator as a candidate (VQ is 'volatile'). 4550 ParamTypes[0] = ArithmeticTypes[Left]; 4551 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 4552 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4553 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4554 } 4555 } 4556 } 4557 break; 4558 4559 case OO_Exclaim: { 4560 // C++ [over.operator]p23: 4561 // 4562 // There also exist candidate operator functions of the form 4563 // 4564 // bool operator!(bool); 4565 // bool operator&&(bool, bool); [BELOW] 4566 // bool operator||(bool, bool); [BELOW] 4567 QualType ParamTy = Context.BoolTy; 4568 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 4569 /*IsAssignmentOperator=*/false, 4570 /*NumContextualBoolArguments=*/1); 4571 break; 4572 } 4573 4574 case OO_AmpAmp: 4575 case OO_PipePipe: { 4576 // C++ [over.operator]p23: 4577 // 4578 // There also exist candidate operator functions of the form 4579 // 4580 // bool operator!(bool); [ABOVE] 4581 // bool operator&&(bool, bool); 4582 // bool operator||(bool, bool); 4583 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 4584 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 4585 /*IsAssignmentOperator=*/false, 4586 /*NumContextualBoolArguments=*/2); 4587 break; 4588 } 4589 4590 case OO_Subscript: 4591 // C++ [over.built]p13: 4592 // 4593 // For every cv-qualified or cv-unqualified object type T there 4594 // exist candidate operator functions of the form 4595 // 4596 // T* operator+(T*, ptrdiff_t); [ABOVE] 4597 // T& operator[](T*, ptrdiff_t); 4598 // T* operator-(T*, ptrdiff_t); [ABOVE] 4599 // T* operator+(ptrdiff_t, T*); [ABOVE] 4600 // T& operator[](ptrdiff_t, T*); 4601 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4602 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4603 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4604 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 4605 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 4606 4607 // T& operator[](T*, ptrdiff_t) 4608 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4609 4610 // T& operator[](ptrdiff_t, T*); 4611 ParamTypes[0] = ParamTypes[1]; 4612 ParamTypes[1] = *Ptr; 4613 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4614 } 4615 break; 4616 4617 case OO_ArrowStar: 4618 // C++ [over.built]p11: 4619 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 4620 // C1 is the same type as C2 or is a derived class of C2, T is an object 4621 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 4622 // there exist candidate operator functions of the form 4623 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 4624 // where CV12 is the union of CV1 and CV2. 4625 { 4626 for (BuiltinCandidateTypeSet::iterator Ptr = 4627 CandidateTypes.pointer_begin(); 4628 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4629 QualType C1Ty = (*Ptr); 4630 QualType C1; 4631 QualifierCollector Q1; 4632 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 4633 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 4634 if (!isa<RecordType>(C1)) 4635 continue; 4636 // heuristic to reduce number of builtin candidates in the set. 4637 // Add volatile/restrict version only if there are conversions to a 4638 // volatile/restrict type. 4639 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 4640 continue; 4641 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4642 continue; 4643 } 4644 for (BuiltinCandidateTypeSet::iterator 4645 MemPtr = CandidateTypes.member_pointer_begin(), 4646 MemPtrEnd = CandidateTypes.member_pointer_end(); 4647 MemPtr != MemPtrEnd; ++MemPtr) { 4648 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4649 QualType C2 = QualType(mptr->getClass(), 0); 4650 C2 = C2.getUnqualifiedType(); 4651 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4652 break; 4653 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4654 // build CV12 T& 4655 QualType T = mptr->getPointeeType(); 4656 if (!VisibleTypeConversionsQuals.hasVolatile() && 4657 T.isVolatileQualified()) 4658 continue; 4659 if (!VisibleTypeConversionsQuals.hasRestrict() && 4660 T.isRestrictQualified()) 4661 continue; 4662 T = Q1.apply(T); 4663 QualType ResultTy = Context.getLValueReferenceType(T); 4664 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4665 } 4666 } 4667 } 4668 break; 4669 4670 case OO_Conditional: 4671 // Note that we don't consider the first argument, since it has been 4672 // contextually converted to bool long ago. The candidates below are 4673 // therefore added as binary. 4674 // 4675 // C++ [over.built]p24: 4676 // For every type T, where T is a pointer or pointer-to-member type, 4677 // there exist candidate operator functions of the form 4678 // 4679 // T operator?(bool, T, T); 4680 // 4681 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4682 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4683 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4684 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4685 } 4686 for (BuiltinCandidateTypeSet::iterator Ptr = 4687 CandidateTypes.member_pointer_begin(), 4688 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4689 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4690 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4691 } 4692 goto Conditional; 4693 } 4694} 4695 4696/// \brief Add function candidates found via argument-dependent lookup 4697/// to the set of overloading candidates. 4698/// 4699/// This routine performs argument-dependent name lookup based on the 4700/// given function name (which may also be an operator name) and adds 4701/// all of the overload candidates found by ADL to the overload 4702/// candidate set (C++ [basic.lookup.argdep]). 4703void 4704Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4705 bool Operator, 4706 Expr **Args, unsigned NumArgs, 4707 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4708 OverloadCandidateSet& CandidateSet, 4709 bool PartialOverloading) { 4710 ADLResult Fns; 4711 4712 // FIXME: This approach for uniquing ADL results (and removing 4713 // redundant candidates from the set) relies on pointer-equality, 4714 // which means we need to key off the canonical decl. However, 4715 // always going back to the canonical decl might not get us the 4716 // right set of default arguments. What default arguments are 4717 // we supposed to consider on ADL candidates, anyway? 4718 4719 // FIXME: Pass in the explicit template arguments? 4720 ArgumentDependentLookup(Name, Operator, Args, NumArgs, Fns); 4721 4722 // Erase all of the candidates we already knew about. 4723 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4724 CandEnd = CandidateSet.end(); 4725 Cand != CandEnd; ++Cand) 4726 if (Cand->Function) { 4727 Fns.erase(Cand->Function); 4728 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4729 Fns.erase(FunTmpl); 4730 } 4731 4732 // For each of the ADL candidates we found, add it to the overload 4733 // set. 4734 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 4735 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); 4736 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 4737 if (ExplicitTemplateArgs) 4738 continue; 4739 4740 AddOverloadCandidate(FD, FoundDecl, Args, NumArgs, CandidateSet, 4741 false, PartialOverloading); 4742 } else 4743 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), 4744 FoundDecl, ExplicitTemplateArgs, 4745 Args, NumArgs, CandidateSet); 4746 } 4747} 4748 4749/// isBetterOverloadCandidate - Determines whether the first overload 4750/// candidate is a better candidate than the second (C++ 13.3.3p1). 4751bool 4752Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4753 const OverloadCandidate& Cand2, 4754 SourceLocation Loc) { 4755 // Define viable functions to be better candidates than non-viable 4756 // functions. 4757 if (!Cand2.Viable) 4758 return Cand1.Viable; 4759 else if (!Cand1.Viable) 4760 return false; 4761 4762 // C++ [over.match.best]p1: 4763 // 4764 // -- if F is a static member function, ICS1(F) is defined such 4765 // that ICS1(F) is neither better nor worse than ICS1(G) for 4766 // any function G, and, symmetrically, ICS1(G) is neither 4767 // better nor worse than ICS1(F). 4768 unsigned StartArg = 0; 4769 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4770 StartArg = 1; 4771 4772 // C++ [over.match.best]p1: 4773 // A viable function F1 is defined to be a better function than another 4774 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4775 // conversion sequence than ICSi(F2), and then... 4776 unsigned NumArgs = Cand1.Conversions.size(); 4777 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4778 bool HasBetterConversion = false; 4779 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4780 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4781 Cand2.Conversions[ArgIdx])) { 4782 case ImplicitConversionSequence::Better: 4783 // Cand1 has a better conversion sequence. 4784 HasBetterConversion = true; 4785 break; 4786 4787 case ImplicitConversionSequence::Worse: 4788 // Cand1 can't be better than Cand2. 4789 return false; 4790 4791 case ImplicitConversionSequence::Indistinguishable: 4792 // Do nothing. 4793 break; 4794 } 4795 } 4796 4797 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4798 // ICSj(F2), or, if not that, 4799 if (HasBetterConversion) 4800 return true; 4801 4802 // - F1 is a non-template function and F2 is a function template 4803 // specialization, or, if not that, 4804 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4805 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4806 return true; 4807 4808 // -- F1 and F2 are function template specializations, and the function 4809 // template for F1 is more specialized than the template for F2 4810 // according to the partial ordering rules described in 14.5.5.2, or, 4811 // if not that, 4812 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4813 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4814 if (FunctionTemplateDecl *BetterTemplate 4815 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4816 Cand2.Function->getPrimaryTemplate(), 4817 Loc, 4818 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4819 : TPOC_Call)) 4820 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4821 4822 // -- the context is an initialization by user-defined conversion 4823 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4824 // from the return type of F1 to the destination type (i.e., 4825 // the type of the entity being initialized) is a better 4826 // conversion sequence than the standard conversion sequence 4827 // from the return type of F2 to the destination type. 4828 if (Cand1.Function && Cand2.Function && 4829 isa<CXXConversionDecl>(Cand1.Function) && 4830 isa<CXXConversionDecl>(Cand2.Function)) { 4831 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4832 Cand2.FinalConversion)) { 4833 case ImplicitConversionSequence::Better: 4834 // Cand1 has a better conversion sequence. 4835 return true; 4836 4837 case ImplicitConversionSequence::Worse: 4838 // Cand1 can't be better than Cand2. 4839 return false; 4840 4841 case ImplicitConversionSequence::Indistinguishable: 4842 // Do nothing 4843 break; 4844 } 4845 } 4846 4847 return false; 4848} 4849 4850/// \brief Computes the best viable function (C++ 13.3.3) 4851/// within an overload candidate set. 4852/// 4853/// \param CandidateSet the set of candidate functions. 4854/// 4855/// \param Loc the location of the function name (or operator symbol) for 4856/// which overload resolution occurs. 4857/// 4858/// \param Best f overload resolution was successful or found a deleted 4859/// function, Best points to the candidate function found. 4860/// 4861/// \returns The result of overload resolution. 4862OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4863 SourceLocation Loc, 4864 OverloadCandidateSet::iterator& Best) { 4865 // Find the best viable function. 4866 Best = CandidateSet.end(); 4867 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4868 Cand != CandidateSet.end(); ++Cand) { 4869 if (Cand->Viable) { 4870 if (Best == CandidateSet.end() || 4871 isBetterOverloadCandidate(*Cand, *Best, Loc)) 4872 Best = Cand; 4873 } 4874 } 4875 4876 // If we didn't find any viable functions, abort. 4877 if (Best == CandidateSet.end()) 4878 return OR_No_Viable_Function; 4879 4880 // Make sure that this function is better than every other viable 4881 // function. If not, we have an ambiguity. 4882 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4883 Cand != CandidateSet.end(); ++Cand) { 4884 if (Cand->Viable && 4885 Cand != Best && 4886 !isBetterOverloadCandidate(*Best, *Cand, Loc)) { 4887 Best = CandidateSet.end(); 4888 return OR_Ambiguous; 4889 } 4890 } 4891 4892 // Best is the best viable function. 4893 if (Best->Function && 4894 (Best->Function->isDeleted() || 4895 Best->Function->getAttr<UnavailableAttr>())) 4896 return OR_Deleted; 4897 4898 // C++ [basic.def.odr]p2: 4899 // An overloaded function is used if it is selected by overload resolution 4900 // when referred to from a potentially-evaluated expression. [Note: this 4901 // covers calls to named functions (5.2.2), operator overloading 4902 // (clause 13), user-defined conversions (12.3.2), allocation function for 4903 // placement new (5.3.4), as well as non-default initialization (8.5). 4904 if (Best->Function) 4905 MarkDeclarationReferenced(Loc, Best->Function); 4906 return OR_Success; 4907} 4908 4909namespace { 4910 4911enum OverloadCandidateKind { 4912 oc_function, 4913 oc_method, 4914 oc_constructor, 4915 oc_function_template, 4916 oc_method_template, 4917 oc_constructor_template, 4918 oc_implicit_default_constructor, 4919 oc_implicit_copy_constructor, 4920 oc_implicit_copy_assignment 4921}; 4922 4923OverloadCandidateKind ClassifyOverloadCandidate(Sema &S, 4924 FunctionDecl *Fn, 4925 std::string &Description) { 4926 bool isTemplate = false; 4927 4928 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { 4929 isTemplate = true; 4930 Description = S.getTemplateArgumentBindingsText( 4931 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); 4932 } 4933 4934 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4935 if (!Ctor->isImplicit()) 4936 return isTemplate ? oc_constructor_template : oc_constructor; 4937 4938 return Ctor->isCopyConstructor() ? oc_implicit_copy_constructor 4939 : oc_implicit_default_constructor; 4940 } 4941 4942 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4943 // This actually gets spelled 'candidate function' for now, but 4944 // it doesn't hurt to split it out. 4945 if (!Meth->isImplicit()) 4946 return isTemplate ? oc_method_template : oc_method; 4947 4948 assert(Meth->isCopyAssignment() 4949 && "implicit method is not copy assignment operator?"); 4950 return oc_implicit_copy_assignment; 4951 } 4952 4953 return isTemplate ? oc_function_template : oc_function; 4954} 4955 4956} // end anonymous namespace 4957 4958// Notes the location of an overload candidate. 4959void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4960 std::string FnDesc; 4961 OverloadCandidateKind K = ClassifyOverloadCandidate(*this, Fn, FnDesc); 4962 Diag(Fn->getLocation(), diag::note_ovl_candidate) 4963 << (unsigned) K << FnDesc; 4964} 4965 4966/// Diagnoses an ambiguous conversion. The partial diagnostic is the 4967/// "lead" diagnostic; it will be given two arguments, the source and 4968/// target types of the conversion. 4969void Sema::DiagnoseAmbiguousConversion(const ImplicitConversionSequence &ICS, 4970 SourceLocation CaretLoc, 4971 const PartialDiagnostic &PDiag) { 4972 Diag(CaretLoc, PDiag) 4973 << ICS.Ambiguous.getFromType() << ICS.Ambiguous.getToType(); 4974 for (AmbiguousConversionSequence::const_iterator 4975 I = ICS.Ambiguous.begin(), E = ICS.Ambiguous.end(); I != E; ++I) { 4976 NoteOverloadCandidate(*I); 4977 } 4978} 4979 4980namespace { 4981 4982void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I) { 4983 const ImplicitConversionSequence &Conv = Cand->Conversions[I]; 4984 assert(Conv.isBad()); 4985 assert(Cand->Function && "for now, candidate must be a function"); 4986 FunctionDecl *Fn = Cand->Function; 4987 4988 // There's a conversion slot for the object argument if this is a 4989 // non-constructor method. Note that 'I' corresponds the 4990 // conversion-slot index. 4991 bool isObjectArgument = false; 4992 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { 4993 if (I == 0) 4994 isObjectArgument = true; 4995 else 4996 I--; 4997 } 4998 4999 std::string FnDesc; 5000 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 5001 5002 Expr *FromExpr = Conv.Bad.FromExpr; 5003 QualType FromTy = Conv.Bad.getFromType(); 5004 QualType ToTy = Conv.Bad.getToType(); 5005 5006 if (FromTy == S.Context.OverloadTy) { 5007 assert(FromExpr && "overload set argument came from implicit argument?"); 5008 Expr *E = FromExpr->IgnoreParens(); 5009 if (isa<UnaryOperator>(E)) 5010 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 5011 DeclarationName Name = cast<OverloadExpr>(E)->getName(); 5012 5013 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) 5014 << (unsigned) FnKind << FnDesc 5015 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5016 << ToTy << Name << I+1; 5017 return; 5018 } 5019 5020 // Do some hand-waving analysis to see if the non-viability is due 5021 // to a qualifier mismatch. 5022 CanQualType CFromTy = S.Context.getCanonicalType(FromTy); 5023 CanQualType CToTy = S.Context.getCanonicalType(ToTy); 5024 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) 5025 CToTy = RT->getPointeeType(); 5026 else { 5027 // TODO: detect and diagnose the full richness of const mismatches. 5028 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) 5029 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) 5030 CFromTy = FromPT->getPointeeType(), CToTy = ToPT->getPointeeType(); 5031 } 5032 5033 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && 5034 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { 5035 // It is dumb that we have to do this here. 5036 while (isa<ArrayType>(CFromTy)) 5037 CFromTy = CFromTy->getAs<ArrayType>()->getElementType(); 5038 while (isa<ArrayType>(CToTy)) 5039 CToTy = CFromTy->getAs<ArrayType>()->getElementType(); 5040 5041 Qualifiers FromQs = CFromTy.getQualifiers(); 5042 Qualifiers ToQs = CToTy.getQualifiers(); 5043 5044 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { 5045 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) 5046 << (unsigned) FnKind << FnDesc 5047 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5048 << FromTy 5049 << FromQs.getAddressSpace() << ToQs.getAddressSpace() 5050 << (unsigned) isObjectArgument << I+1; 5051 return; 5052 } 5053 5054 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); 5055 assert(CVR && "unexpected qualifiers mismatch"); 5056 5057 if (isObjectArgument) { 5058 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) 5059 << (unsigned) FnKind << FnDesc 5060 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5061 << FromTy << (CVR - 1); 5062 } else { 5063 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) 5064 << (unsigned) FnKind << FnDesc 5065 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5066 << FromTy << (CVR - 1) << I+1; 5067 } 5068 return; 5069 } 5070 5071 // Diagnose references or pointers to incomplete types differently, 5072 // since it's far from impossible that the incompleteness triggered 5073 // the failure. 5074 QualType TempFromTy = FromTy.getNonReferenceType(); 5075 if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) 5076 TempFromTy = PTy->getPointeeType(); 5077 if (TempFromTy->isIncompleteType()) { 5078 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) 5079 << (unsigned) FnKind << FnDesc 5080 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5081 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 5082 return; 5083 } 5084 5085 // TODO: specialize more based on the kind of mismatch 5086 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv) 5087 << (unsigned) FnKind << FnDesc 5088 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 5089 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 5090} 5091 5092void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, 5093 unsigned NumFormalArgs) { 5094 // TODO: treat calls to a missing default constructor as a special case 5095 5096 FunctionDecl *Fn = Cand->Function; 5097 const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); 5098 5099 unsigned MinParams = Fn->getMinRequiredArguments(); 5100 5101 // at least / at most / exactly 5102 // FIXME: variadic templates "at most" should account for parameter packs 5103 unsigned mode, modeCount; 5104 if (NumFormalArgs < MinParams) { 5105 assert((Cand->FailureKind == ovl_fail_too_few_arguments) || 5106 (Cand->FailureKind == ovl_fail_bad_deduction && 5107 Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments)); 5108 if (MinParams != FnTy->getNumArgs() || FnTy->isVariadic()) 5109 mode = 0; // "at least" 5110 else 5111 mode = 2; // "exactly" 5112 modeCount = MinParams; 5113 } else { 5114 assert((Cand->FailureKind == ovl_fail_too_many_arguments) || 5115 (Cand->FailureKind == ovl_fail_bad_deduction && 5116 Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments)); 5117 if (MinParams != FnTy->getNumArgs()) 5118 mode = 1; // "at most" 5119 else 5120 mode = 2; // "exactly" 5121 modeCount = FnTy->getNumArgs(); 5122 } 5123 5124 std::string Description; 5125 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, Description); 5126 5127 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) 5128 << (unsigned) FnKind << (Fn->getDescribedFunctionTemplate() != 0) << mode 5129 << modeCount << NumFormalArgs; 5130} 5131 5132/// Diagnose a failed template-argument deduction. 5133void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, 5134 Expr **Args, unsigned NumArgs) { 5135 FunctionDecl *Fn = Cand->Function; // pattern 5136 5137 TemplateParameter Param = Cand->DeductionFailure.getTemplateParameter(); 5138 NamedDecl *ParamD; 5139 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || 5140 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || 5141 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); 5142 switch (Cand->DeductionFailure.Result) { 5143 case Sema::TDK_Success: 5144 llvm_unreachable("TDK_success while diagnosing bad deduction"); 5145 5146 case Sema::TDK_Incomplete: { 5147 assert(ParamD && "no parameter found for incomplete deduction result"); 5148 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_incomplete_deduction) 5149 << ParamD->getDeclName(); 5150 return; 5151 } 5152 5153 case Sema::TDK_Inconsistent: 5154 case Sema::TDK_InconsistentQuals: { 5155 assert(ParamD && "no parameter found for inconsistent deduction result"); 5156 int which = 0; 5157 if (isa<TemplateTypeParmDecl>(ParamD)) 5158 which = 0; 5159 else if (isa<NonTypeTemplateParmDecl>(ParamD)) 5160 which = 1; 5161 else { 5162 which = 2; 5163 } 5164 5165 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_inconsistent_deduction) 5166 << which << ParamD->getDeclName() 5167 << *Cand->DeductionFailure.getFirstArg() 5168 << *Cand->DeductionFailure.getSecondArg(); 5169 return; 5170 } 5171 5172 case Sema::TDK_InvalidExplicitArguments: 5173 assert(ParamD && "no parameter found for invalid explicit arguments"); 5174 if (ParamD->getDeclName()) 5175 S.Diag(Fn->getLocation(), 5176 diag::note_ovl_candidate_explicit_arg_mismatch_named) 5177 << ParamD->getDeclName(); 5178 else { 5179 int index = 0; 5180 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD)) 5181 index = TTP->getIndex(); 5182 else if (NonTypeTemplateParmDecl *NTTP 5183 = dyn_cast<NonTypeTemplateParmDecl>(ParamD)) 5184 index = NTTP->getIndex(); 5185 else 5186 index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex(); 5187 S.Diag(Fn->getLocation(), 5188 diag::note_ovl_candidate_explicit_arg_mismatch_unnamed) 5189 << (index + 1); 5190 } 5191 return; 5192 5193 case Sema::TDK_TooManyArguments: 5194 case Sema::TDK_TooFewArguments: 5195 DiagnoseArityMismatch(S, Cand, NumArgs); 5196 return; 5197 5198 case Sema::TDK_InstantiationDepth: 5199 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_instantiation_depth); 5200 return; 5201 5202 case Sema::TDK_SubstitutionFailure: { 5203 std::string ArgString; 5204 if (TemplateArgumentList *Args 5205 = Cand->DeductionFailure.getTemplateArgumentList()) 5206 ArgString = S.getTemplateArgumentBindingsText( 5207 Fn->getDescribedFunctionTemplate()->getTemplateParameters(), 5208 *Args); 5209 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_substitution_failure) 5210 << ArgString; 5211 return; 5212 } 5213 5214 // TODO: diagnose these individually, then kill off 5215 // note_ovl_candidate_bad_deduction, which is uselessly vague. 5216 case Sema::TDK_NonDeducedMismatch: 5217 case Sema::TDK_FailedOverloadResolution: 5218 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction); 5219 return; 5220 } 5221} 5222 5223/// Generates a 'note' diagnostic for an overload candidate. We've 5224/// already generated a primary error at the call site. 5225/// 5226/// It really does need to be a single diagnostic with its caret 5227/// pointed at the candidate declaration. Yes, this creates some 5228/// major challenges of technical writing. Yes, this makes pointing 5229/// out problems with specific arguments quite awkward. It's still 5230/// better than generating twenty screens of text for every failed 5231/// overload. 5232/// 5233/// It would be great to be able to express per-candidate problems 5234/// more richly for those diagnostic clients that cared, but we'd 5235/// still have to be just as careful with the default diagnostics. 5236void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, 5237 Expr **Args, unsigned NumArgs) { 5238 FunctionDecl *Fn = Cand->Function; 5239 5240 // Note deleted candidates, but only if they're viable. 5241 if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) { 5242 std::string FnDesc; 5243 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 5244 5245 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) 5246 << FnKind << FnDesc << Fn->isDeleted(); 5247 return; 5248 } 5249 5250 // We don't really have anything else to say about viable candidates. 5251 if (Cand->Viable) { 5252 S.NoteOverloadCandidate(Fn); 5253 return; 5254 } 5255 5256 switch (Cand->FailureKind) { 5257 case ovl_fail_too_many_arguments: 5258 case ovl_fail_too_few_arguments: 5259 return DiagnoseArityMismatch(S, Cand, NumArgs); 5260 5261 case ovl_fail_bad_deduction: 5262 return DiagnoseBadDeduction(S, Cand, Args, NumArgs); 5263 5264 case ovl_fail_trivial_conversion: 5265 case ovl_fail_bad_final_conversion: 5266 case ovl_fail_final_conversion_not_exact: 5267 return S.NoteOverloadCandidate(Fn); 5268 5269 case ovl_fail_bad_conversion: { 5270 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); 5271 for (unsigned N = Cand->Conversions.size(); I != N; ++I) 5272 if (Cand->Conversions[I].isBad()) 5273 return DiagnoseBadConversion(S, Cand, I); 5274 5275 // FIXME: this currently happens when we're called from SemaInit 5276 // when user-conversion overload fails. Figure out how to handle 5277 // those conditions and diagnose them well. 5278 return S.NoteOverloadCandidate(Fn); 5279 } 5280 } 5281} 5282 5283void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 5284 // Desugar the type of the surrogate down to a function type, 5285 // retaining as many typedefs as possible while still showing 5286 // the function type (and, therefore, its parameter types). 5287 QualType FnType = Cand->Surrogate->getConversionType(); 5288 bool isLValueReference = false; 5289 bool isRValueReference = false; 5290 bool isPointer = false; 5291 if (const LValueReferenceType *FnTypeRef = 5292 FnType->getAs<LValueReferenceType>()) { 5293 FnType = FnTypeRef->getPointeeType(); 5294 isLValueReference = true; 5295 } else if (const RValueReferenceType *FnTypeRef = 5296 FnType->getAs<RValueReferenceType>()) { 5297 FnType = FnTypeRef->getPointeeType(); 5298 isRValueReference = true; 5299 } 5300 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 5301 FnType = FnTypePtr->getPointeeType(); 5302 isPointer = true; 5303 } 5304 // Desugar down to a function type. 5305 FnType = QualType(FnType->getAs<FunctionType>(), 0); 5306 // Reconstruct the pointer/reference as appropriate. 5307 if (isPointer) FnType = S.Context.getPointerType(FnType); 5308 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 5309 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 5310 5311 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 5312 << FnType; 5313} 5314 5315void NoteBuiltinOperatorCandidate(Sema &S, 5316 const char *Opc, 5317 SourceLocation OpLoc, 5318 OverloadCandidate *Cand) { 5319 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 5320 std::string TypeStr("operator"); 5321 TypeStr += Opc; 5322 TypeStr += "("; 5323 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 5324 if (Cand->Conversions.size() == 1) { 5325 TypeStr += ")"; 5326 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 5327 } else { 5328 TypeStr += ", "; 5329 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 5330 TypeStr += ")"; 5331 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 5332 } 5333} 5334 5335void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 5336 OverloadCandidate *Cand) { 5337 unsigned NoOperands = Cand->Conversions.size(); 5338 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 5339 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 5340 if (ICS.isBad()) break; // all meaningless after first invalid 5341 if (!ICS.isAmbiguous()) continue; 5342 5343 S.DiagnoseAmbiguousConversion(ICS, OpLoc, 5344 S.PDiag(diag::note_ambiguous_type_conversion)); 5345 } 5346} 5347 5348SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { 5349 if (Cand->Function) 5350 return Cand->Function->getLocation(); 5351 if (Cand->IsSurrogate) 5352 return Cand->Surrogate->getLocation(); 5353 return SourceLocation(); 5354} 5355 5356struct CompareOverloadCandidatesForDisplay { 5357 Sema &S; 5358 CompareOverloadCandidatesForDisplay(Sema &S) : S(S) {} 5359 5360 bool operator()(const OverloadCandidate *L, 5361 const OverloadCandidate *R) { 5362 // Fast-path this check. 5363 if (L == R) return false; 5364 5365 // Order first by viability. 5366 if (L->Viable) { 5367 if (!R->Viable) return true; 5368 5369 // TODO: introduce a tri-valued comparison for overload 5370 // candidates. Would be more worthwhile if we had a sort 5371 // that could exploit it. 5372 if (S.isBetterOverloadCandidate(*L, *R, SourceLocation())) return true; 5373 if (S.isBetterOverloadCandidate(*R, *L, SourceLocation())) return false; 5374 } else if (R->Viable) 5375 return false; 5376 5377 assert(L->Viable == R->Viable); 5378 5379 // Criteria by which we can sort non-viable candidates: 5380 if (!L->Viable) { 5381 // 1. Arity mismatches come after other candidates. 5382 if (L->FailureKind == ovl_fail_too_many_arguments || 5383 L->FailureKind == ovl_fail_too_few_arguments) 5384 return false; 5385 if (R->FailureKind == ovl_fail_too_many_arguments || 5386 R->FailureKind == ovl_fail_too_few_arguments) 5387 return true; 5388 5389 // 2. Bad conversions come first and are ordered by the number 5390 // of bad conversions and quality of good conversions. 5391 if (L->FailureKind == ovl_fail_bad_conversion) { 5392 if (R->FailureKind != ovl_fail_bad_conversion) 5393 return true; 5394 5395 // If there's any ordering between the defined conversions... 5396 // FIXME: this might not be transitive. 5397 assert(L->Conversions.size() == R->Conversions.size()); 5398 5399 int leftBetter = 0; 5400 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); 5401 for (unsigned E = L->Conversions.size(); I != E; ++I) { 5402 switch (S.CompareImplicitConversionSequences(L->Conversions[I], 5403 R->Conversions[I])) { 5404 case ImplicitConversionSequence::Better: 5405 leftBetter++; 5406 break; 5407 5408 case ImplicitConversionSequence::Worse: 5409 leftBetter--; 5410 break; 5411 5412 case ImplicitConversionSequence::Indistinguishable: 5413 break; 5414 } 5415 } 5416 if (leftBetter > 0) return true; 5417 if (leftBetter < 0) return false; 5418 5419 } else if (R->FailureKind == ovl_fail_bad_conversion) 5420 return false; 5421 5422 // TODO: others? 5423 } 5424 5425 // Sort everything else by location. 5426 SourceLocation LLoc = GetLocationForCandidate(L); 5427 SourceLocation RLoc = GetLocationForCandidate(R); 5428 5429 // Put candidates without locations (e.g. builtins) at the end. 5430 if (LLoc.isInvalid()) return false; 5431 if (RLoc.isInvalid()) return true; 5432 5433 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); 5434 } 5435}; 5436 5437/// CompleteNonViableCandidate - Normally, overload resolution only 5438/// computes up to the first 5439void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, 5440 Expr **Args, unsigned NumArgs) { 5441 assert(!Cand->Viable); 5442 5443 // Don't do anything on failures other than bad conversion. 5444 if (Cand->FailureKind != ovl_fail_bad_conversion) return; 5445 5446 // Skip forward to the first bad conversion. 5447 unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); 5448 unsigned ConvCount = Cand->Conversions.size(); 5449 while (true) { 5450 assert(ConvIdx != ConvCount && "no bad conversion in candidate"); 5451 ConvIdx++; 5452 if (Cand->Conversions[ConvIdx - 1].isBad()) 5453 break; 5454 } 5455 5456 if (ConvIdx == ConvCount) 5457 return; 5458 5459 assert(!Cand->Conversions[ConvIdx].isInitialized() && 5460 "remaining conversion is initialized?"); 5461 5462 // FIXME: this should probably be preserved from the overload 5463 // operation somehow. 5464 bool SuppressUserConversions = false; 5465 5466 const FunctionProtoType* Proto; 5467 unsigned ArgIdx = ConvIdx; 5468 5469 if (Cand->IsSurrogate) { 5470 QualType ConvType 5471 = Cand->Surrogate->getConversionType().getNonReferenceType(); 5472 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5473 ConvType = ConvPtrType->getPointeeType(); 5474 Proto = ConvType->getAs<FunctionProtoType>(); 5475 ArgIdx--; 5476 } else if (Cand->Function) { 5477 Proto = Cand->Function->getType()->getAs<FunctionProtoType>(); 5478 if (isa<CXXMethodDecl>(Cand->Function) && 5479 !isa<CXXConstructorDecl>(Cand->Function)) 5480 ArgIdx--; 5481 } else { 5482 // Builtin binary operator with a bad first conversion. 5483 assert(ConvCount <= 3); 5484 for (; ConvIdx != ConvCount; ++ConvIdx) 5485 Cand->Conversions[ConvIdx] 5486 = TryCopyInitialization(S, Args[ConvIdx], 5487 Cand->BuiltinTypes.ParamTypes[ConvIdx], 5488 SuppressUserConversions, 5489 /*InOverloadResolution*/ true); 5490 return; 5491 } 5492 5493 // Fill in the rest of the conversions. 5494 unsigned NumArgsInProto = Proto->getNumArgs(); 5495 for (; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { 5496 if (ArgIdx < NumArgsInProto) 5497 Cand->Conversions[ConvIdx] 5498 = TryCopyInitialization(S, Args[ArgIdx], Proto->getArgType(ArgIdx), 5499 SuppressUserConversions, 5500 /*InOverloadResolution=*/true); 5501 else 5502 Cand->Conversions[ConvIdx].setEllipsis(); 5503 } 5504} 5505 5506} // end anonymous namespace 5507 5508/// PrintOverloadCandidates - When overload resolution fails, prints 5509/// diagnostic messages containing the candidates in the candidate 5510/// set. 5511void 5512Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 5513 OverloadCandidateDisplayKind OCD, 5514 Expr **Args, unsigned NumArgs, 5515 const char *Opc, 5516 SourceLocation OpLoc) { 5517 // Sort the candidates by viability and position. Sorting directly would 5518 // be prohibitive, so we make a set of pointers and sort those. 5519 llvm::SmallVector<OverloadCandidate*, 32> Cands; 5520 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 5521 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 5522 LastCand = CandidateSet.end(); 5523 Cand != LastCand; ++Cand) { 5524 if (Cand->Viable) 5525 Cands.push_back(Cand); 5526 else if (OCD == OCD_AllCandidates) { 5527 CompleteNonViableCandidate(*this, Cand, Args, NumArgs); 5528 Cands.push_back(Cand); 5529 } 5530 } 5531 5532 std::sort(Cands.begin(), Cands.end(), 5533 CompareOverloadCandidatesForDisplay(*this)); 5534 5535 bool ReportedAmbiguousConversions = false; 5536 5537 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 5538 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 5539 OverloadCandidate *Cand = *I; 5540 5541 if (Cand->Function) 5542 NoteFunctionCandidate(*this, Cand, Args, NumArgs); 5543 else if (Cand->IsSurrogate) 5544 NoteSurrogateCandidate(*this, Cand); 5545 5546 // This a builtin candidate. We do not, in general, want to list 5547 // every possible builtin candidate. 5548 else if (Cand->Viable) { 5549 // Generally we only see ambiguities including viable builtin 5550 // operators if overload resolution got screwed up by an 5551 // ambiguous user-defined conversion. 5552 // 5553 // FIXME: It's quite possible for different conversions to see 5554 // different ambiguities, though. 5555 if (!ReportedAmbiguousConversions) { 5556 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 5557 ReportedAmbiguousConversions = true; 5558 } 5559 5560 // If this is a viable builtin, print it. 5561 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 5562 } 5563 } 5564} 5565 5566static bool CheckUnresolvedAccess(Sema &S, OverloadExpr *E, DeclAccessPair D) { 5567 if (isa<UnresolvedLookupExpr>(E)) 5568 return S.CheckUnresolvedLookupAccess(cast<UnresolvedLookupExpr>(E), D); 5569 5570 return S.CheckUnresolvedMemberAccess(cast<UnresolvedMemberExpr>(E), D); 5571} 5572 5573/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 5574/// an overloaded function (C++ [over.over]), where @p From is an 5575/// expression with overloaded function type and @p ToType is the type 5576/// we're trying to resolve to. For example: 5577/// 5578/// @code 5579/// int f(double); 5580/// int f(int); 5581/// 5582/// int (*pfd)(double) = f; // selects f(double) 5583/// @endcode 5584/// 5585/// This routine returns the resulting FunctionDecl if it could be 5586/// resolved, and NULL otherwise. When @p Complain is true, this 5587/// routine will emit diagnostics if there is an error. 5588FunctionDecl * 5589Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 5590 bool Complain, 5591 DeclAccessPair &FoundResult) { 5592 QualType FunctionType = ToType; 5593 bool IsMember = false; 5594 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 5595 FunctionType = ToTypePtr->getPointeeType(); 5596 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 5597 FunctionType = ToTypeRef->getPointeeType(); 5598 else if (const MemberPointerType *MemTypePtr = 5599 ToType->getAs<MemberPointerType>()) { 5600 FunctionType = MemTypePtr->getPointeeType(); 5601 IsMember = true; 5602 } 5603 5604 // C++ [over.over]p1: 5605 // [...] [Note: any redundant set of parentheses surrounding the 5606 // overloaded function name is ignored (5.1). ] 5607 // C++ [over.over]p1: 5608 // [...] The overloaded function name can be preceded by the & 5609 // operator. 5610 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5611 TemplateArgumentListInfo ETABuffer, *ExplicitTemplateArgs = 0; 5612 if (OvlExpr->hasExplicitTemplateArgs()) { 5613 OvlExpr->getExplicitTemplateArgs().copyInto(ETABuffer); 5614 ExplicitTemplateArgs = &ETABuffer; 5615 } 5616 5617 // We expect a pointer or reference to function, or a function pointer. 5618 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 5619 if (!FunctionType->isFunctionType()) { 5620 if (Complain) 5621 Diag(From->getLocStart(), diag::err_addr_ovl_not_func_ptrref) 5622 << OvlExpr->getName() << ToType; 5623 5624 return 0; 5625 } 5626 5627 assert(From->getType() == Context.OverloadTy); 5628 5629 // Look through all of the overloaded functions, searching for one 5630 // whose type matches exactly. 5631 llvm::SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; 5632 llvm::SmallVector<FunctionDecl *, 4> NonMatches; 5633 5634 bool FoundNonTemplateFunction = false; 5635 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5636 E = OvlExpr->decls_end(); I != E; ++I) { 5637 // Look through any using declarations to find the underlying function. 5638 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 5639 5640 // C++ [over.over]p3: 5641 // Non-member functions and static member functions match 5642 // targets of type "pointer-to-function" or "reference-to-function." 5643 // Nonstatic member functions match targets of 5644 // type "pointer-to-member-function." 5645 // Note that according to DR 247, the containing class does not matter. 5646 5647 if (FunctionTemplateDecl *FunctionTemplate 5648 = dyn_cast<FunctionTemplateDecl>(Fn)) { 5649 if (CXXMethodDecl *Method 5650 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 5651 // Skip non-static function templates when converting to pointer, and 5652 // static when converting to member pointer. 5653 if (Method->isStatic() == IsMember) 5654 continue; 5655 } else if (IsMember) 5656 continue; 5657 5658 // C++ [over.over]p2: 5659 // If the name is a function template, template argument deduction is 5660 // done (14.8.2.2), and if the argument deduction succeeds, the 5661 // resulting template argument list is used to generate a single 5662 // function template specialization, which is added to the set of 5663 // overloaded functions considered. 5664 // FIXME: We don't really want to build the specialization here, do we? 5665 FunctionDecl *Specialization = 0; 5666 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5667 if (TemplateDeductionResult Result 5668 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 5669 FunctionType, Specialization, Info)) { 5670 // FIXME: make a note of the failed deduction for diagnostics. 5671 (void)Result; 5672 } else { 5673 // FIXME: If the match isn't exact, shouldn't we just drop this as 5674 // a candidate? Find a testcase before changing the code. 5675 assert(FunctionType 5676 == Context.getCanonicalType(Specialization->getType())); 5677 Matches.push_back(std::make_pair(I.getPair(), 5678 cast<FunctionDecl>(Specialization->getCanonicalDecl()))); 5679 } 5680 5681 continue; 5682 } 5683 5684 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 5685 // Skip non-static functions when converting to pointer, and static 5686 // when converting to member pointer. 5687 if (Method->isStatic() == IsMember) 5688 continue; 5689 5690 // If we have explicit template arguments, skip non-templates. 5691 if (OvlExpr->hasExplicitTemplateArgs()) 5692 continue; 5693 } else if (IsMember) 5694 continue; 5695 5696 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 5697 QualType ResultTy; 5698 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 5699 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 5700 ResultTy)) { 5701 Matches.push_back(std::make_pair(I.getPair(), 5702 cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); 5703 FoundNonTemplateFunction = true; 5704 } 5705 } 5706 } 5707 5708 // If there were 0 or 1 matches, we're done. 5709 if (Matches.empty()) { 5710 if (Complain) { 5711 Diag(From->getLocStart(), diag::err_addr_ovl_no_viable) 5712 << OvlExpr->getName() << FunctionType; 5713 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5714 E = OvlExpr->decls_end(); 5715 I != E; ++I) 5716 if (FunctionDecl *F = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) 5717 NoteOverloadCandidate(F); 5718 } 5719 5720 return 0; 5721 } else if (Matches.size() == 1) { 5722 FunctionDecl *Result = Matches[0].second; 5723 FoundResult = Matches[0].first; 5724 MarkDeclarationReferenced(From->getLocStart(), Result); 5725 if (Complain) 5726 CheckAddressOfMemberAccess(OvlExpr, Matches[0].first); 5727 return Result; 5728 } 5729 5730 // C++ [over.over]p4: 5731 // If more than one function is selected, [...] 5732 if (!FoundNonTemplateFunction) { 5733 // [...] and any given function template specialization F1 is 5734 // eliminated if the set contains a second function template 5735 // specialization whose function template is more specialized 5736 // than the function template of F1 according to the partial 5737 // ordering rules of 14.5.5.2. 5738 5739 // The algorithm specified above is quadratic. We instead use a 5740 // two-pass algorithm (similar to the one used to identify the 5741 // best viable function in an overload set) that identifies the 5742 // best function template (if it exists). 5743 5744 UnresolvedSet<4> MatchesCopy; // TODO: avoid! 5745 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5746 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); 5747 5748 UnresolvedSetIterator Result = 5749 getMostSpecialized(MatchesCopy.begin(), MatchesCopy.end(), 5750 TPOC_Other, From->getLocStart(), 5751 PDiag(), 5752 PDiag(diag::err_addr_ovl_ambiguous) 5753 << Matches[0].second->getDeclName(), 5754 PDiag(diag::note_ovl_candidate) 5755 << (unsigned) oc_function_template); 5756 assert(Result != MatchesCopy.end() && "no most-specialized template"); 5757 MarkDeclarationReferenced(From->getLocStart(), *Result); 5758 FoundResult = Matches[Result - MatchesCopy.begin()].first; 5759 if (Complain) { 5760 CheckUnresolvedAccess(*this, OvlExpr, FoundResult); 5761 DiagnoseUseOfDecl(FoundResult, OvlExpr->getNameLoc()); 5762 } 5763 return cast<FunctionDecl>(*Result); 5764 } 5765 5766 // [...] any function template specializations in the set are 5767 // eliminated if the set also contains a non-template function, [...] 5768 for (unsigned I = 0, N = Matches.size(); I != N; ) { 5769 if (Matches[I].second->getPrimaryTemplate() == 0) 5770 ++I; 5771 else { 5772 Matches[I] = Matches[--N]; 5773 Matches.set_size(N); 5774 } 5775 } 5776 5777 // [...] After such eliminations, if any, there shall remain exactly one 5778 // selected function. 5779 if (Matches.size() == 1) { 5780 MarkDeclarationReferenced(From->getLocStart(), Matches[0].second); 5781 FoundResult = Matches[0].first; 5782 if (Complain) { 5783 CheckUnresolvedAccess(*this, OvlExpr, Matches[0].first); 5784 DiagnoseUseOfDecl(Matches[0].first, OvlExpr->getNameLoc()); 5785 } 5786 return cast<FunctionDecl>(Matches[0].second); 5787 } 5788 5789 // FIXME: We should probably return the same thing that BestViableFunction 5790 // returns (even if we issue the diagnostics here). 5791 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 5792 << Matches[0].second->getDeclName(); 5793 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5794 NoteOverloadCandidate(Matches[I].second); 5795 return 0; 5796} 5797 5798/// \brief Given an expression that refers to an overloaded function, try to 5799/// resolve that overloaded function expression down to a single function. 5800/// 5801/// This routine can only resolve template-ids that refer to a single function 5802/// template, where that template-id refers to a single template whose template 5803/// arguments are either provided by the template-id or have defaults, 5804/// as described in C++0x [temp.arg.explicit]p3. 5805FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 5806 // C++ [over.over]p1: 5807 // [...] [Note: any redundant set of parentheses surrounding the 5808 // overloaded function name is ignored (5.1). ] 5809 // C++ [over.over]p1: 5810 // [...] The overloaded function name can be preceded by the & 5811 // operator. 5812 5813 if (From->getType() != Context.OverloadTy) 5814 return 0; 5815 5816 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5817 5818 // If we didn't actually find any template-ids, we're done. 5819 if (!OvlExpr->hasExplicitTemplateArgs()) 5820 return 0; 5821 5822 TemplateArgumentListInfo ExplicitTemplateArgs; 5823 OvlExpr->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 5824 5825 // Look through all of the overloaded functions, searching for one 5826 // whose type matches exactly. 5827 FunctionDecl *Matched = 0; 5828 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5829 E = OvlExpr->decls_end(); I != E; ++I) { 5830 // C++0x [temp.arg.explicit]p3: 5831 // [...] In contexts where deduction is done and fails, or in contexts 5832 // where deduction is not done, if a template argument list is 5833 // specified and it, along with any default template arguments, 5834 // identifies a single function template specialization, then the 5835 // template-id is an lvalue for the function template specialization. 5836 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 5837 5838 // C++ [over.over]p2: 5839 // If the name is a function template, template argument deduction is 5840 // done (14.8.2.2), and if the argument deduction succeeds, the 5841 // resulting template argument list is used to generate a single 5842 // function template specialization, which is added to the set of 5843 // overloaded functions considered. 5844 FunctionDecl *Specialization = 0; 5845 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5846 if (TemplateDeductionResult Result 5847 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 5848 Specialization, Info)) { 5849 // FIXME: make a note of the failed deduction for diagnostics. 5850 (void)Result; 5851 continue; 5852 } 5853 5854 // Multiple matches; we can't resolve to a single declaration. 5855 if (Matched) 5856 return 0; 5857 5858 Matched = Specialization; 5859 } 5860 5861 return Matched; 5862} 5863 5864/// \brief Add a single candidate to the overload set. 5865static void AddOverloadedCallCandidate(Sema &S, 5866 DeclAccessPair FoundDecl, 5867 const TemplateArgumentListInfo *ExplicitTemplateArgs, 5868 Expr **Args, unsigned NumArgs, 5869 OverloadCandidateSet &CandidateSet, 5870 bool PartialOverloading) { 5871 NamedDecl *Callee = FoundDecl.getDecl(); 5872 if (isa<UsingShadowDecl>(Callee)) 5873 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 5874 5875 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 5876 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 5877 S.AddOverloadCandidate(Func, FoundDecl, Args, NumArgs, CandidateSet, 5878 false, PartialOverloading); 5879 return; 5880 } 5881 5882 if (FunctionTemplateDecl *FuncTemplate 5883 = dyn_cast<FunctionTemplateDecl>(Callee)) { 5884 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, 5885 ExplicitTemplateArgs, 5886 Args, NumArgs, CandidateSet); 5887 return; 5888 } 5889 5890 assert(false && "unhandled case in overloaded call candidate"); 5891 5892 // do nothing? 5893} 5894 5895/// \brief Add the overload candidates named by callee and/or found by argument 5896/// dependent lookup to the given overload set. 5897void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 5898 Expr **Args, unsigned NumArgs, 5899 OverloadCandidateSet &CandidateSet, 5900 bool PartialOverloading) { 5901 5902#ifndef NDEBUG 5903 // Verify that ArgumentDependentLookup is consistent with the rules 5904 // in C++0x [basic.lookup.argdep]p3: 5905 // 5906 // Let X be the lookup set produced by unqualified lookup (3.4.1) 5907 // and let Y be the lookup set produced by argument dependent 5908 // lookup (defined as follows). If X contains 5909 // 5910 // -- a declaration of a class member, or 5911 // 5912 // -- a block-scope function declaration that is not a 5913 // using-declaration, or 5914 // 5915 // -- a declaration that is neither a function or a function 5916 // template 5917 // 5918 // then Y is empty. 5919 5920 if (ULE->requiresADL()) { 5921 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5922 E = ULE->decls_end(); I != E; ++I) { 5923 assert(!(*I)->getDeclContext()->isRecord()); 5924 assert(isa<UsingShadowDecl>(*I) || 5925 !(*I)->getDeclContext()->isFunctionOrMethod()); 5926 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 5927 } 5928 } 5929#endif 5930 5931 // It would be nice to avoid this copy. 5932 TemplateArgumentListInfo TABuffer; 5933 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5934 if (ULE->hasExplicitTemplateArgs()) { 5935 ULE->copyTemplateArgumentsInto(TABuffer); 5936 ExplicitTemplateArgs = &TABuffer; 5937 } 5938 5939 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5940 E = ULE->decls_end(); I != E; ++I) 5941 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, 5942 Args, NumArgs, CandidateSet, 5943 PartialOverloading); 5944 5945 if (ULE->requiresADL()) 5946 AddArgumentDependentLookupCandidates(ULE->getName(), /*Operator*/ false, 5947 Args, NumArgs, 5948 ExplicitTemplateArgs, 5949 CandidateSet, 5950 PartialOverloading); 5951} 5952 5953static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 5954 Expr **Args, unsigned NumArgs) { 5955 Fn->Destroy(SemaRef.Context); 5956 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5957 Args[Arg]->Destroy(SemaRef.Context); 5958 return SemaRef.ExprError(); 5959} 5960 5961/// Attempts to recover from a call where no functions were found. 5962/// 5963/// Returns true if new candidates were found. 5964static Sema::OwningExprResult 5965BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, 5966 UnresolvedLookupExpr *ULE, 5967 SourceLocation LParenLoc, 5968 Expr **Args, unsigned NumArgs, 5969 SourceLocation *CommaLocs, 5970 SourceLocation RParenLoc) { 5971 5972 CXXScopeSpec SS; 5973 if (ULE->getQualifier()) { 5974 SS.setScopeRep(ULE->getQualifier()); 5975 SS.setRange(ULE->getQualifierRange()); 5976 } 5977 5978 TemplateArgumentListInfo TABuffer; 5979 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5980 if (ULE->hasExplicitTemplateArgs()) { 5981 ULE->copyTemplateArgumentsInto(TABuffer); 5982 ExplicitTemplateArgs = &TABuffer; 5983 } 5984 5985 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 5986 Sema::LookupOrdinaryName); 5987 if (SemaRef.DiagnoseEmptyLookup(S, SS, R)) 5988 return Destroy(SemaRef, Fn, Args, NumArgs); 5989 5990 assert(!R.empty() && "lookup results empty despite recovery"); 5991 5992 // Build an implicit member call if appropriate. Just drop the 5993 // casts and such from the call, we don't really care. 5994 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 5995 if ((*R.begin())->isCXXClassMember()) 5996 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 5997 else if (ExplicitTemplateArgs) 5998 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 5999 else 6000 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 6001 6002 if (NewFn.isInvalid()) 6003 return Destroy(SemaRef, Fn, Args, NumArgs); 6004 6005 Fn->Destroy(SemaRef.Context); 6006 6007 // This shouldn't cause an infinite loop because we're giving it 6008 // an expression with non-empty lookup results, which should never 6009 // end up here. 6010 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 6011 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 6012 CommaLocs, RParenLoc); 6013} 6014 6015/// ResolveOverloadedCallFn - Given the call expression that calls Fn 6016/// (which eventually refers to the declaration Func) and the call 6017/// arguments Args/NumArgs, attempt to resolve the function call down 6018/// to a specific function. If overload resolution succeeds, returns 6019/// the function declaration produced by overload 6020/// resolution. Otherwise, emits diagnostics, deletes all of the 6021/// arguments and Fn, and returns NULL. 6022Sema::OwningExprResult 6023Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, 6024 SourceLocation LParenLoc, 6025 Expr **Args, unsigned NumArgs, 6026 SourceLocation *CommaLocs, 6027 SourceLocation RParenLoc) { 6028#ifndef NDEBUG 6029 if (ULE->requiresADL()) { 6030 // To do ADL, we must have found an unqualified name. 6031 assert(!ULE->getQualifier() && "qualified name with ADL"); 6032 6033 // We don't perform ADL for implicit declarations of builtins. 6034 // Verify that this was correctly set up. 6035 FunctionDecl *F; 6036 if (ULE->decls_begin() + 1 == ULE->decls_end() && 6037 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 6038 F->getBuiltinID() && F->isImplicit()) 6039 assert(0 && "performing ADL for builtin"); 6040 6041 // We don't perform ADL in C. 6042 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 6043 } 6044#endif 6045 6046 OverloadCandidateSet CandidateSet(Fn->getExprLoc()); 6047 6048 // Add the functions denoted by the callee to the set of candidate 6049 // functions, including those from argument-dependent lookup. 6050 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 6051 6052 // If we found nothing, try to recover. 6053 // AddRecoveryCallCandidates diagnoses the error itself, so we just 6054 // bailout out if it fails. 6055 if (CandidateSet.empty()) 6056 return BuildRecoveryCallExpr(*this, S, Fn, ULE, LParenLoc, Args, NumArgs, 6057 CommaLocs, RParenLoc); 6058 6059 OverloadCandidateSet::iterator Best; 6060 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 6061 case OR_Success: { 6062 FunctionDecl *FDecl = Best->Function; 6063 CheckUnresolvedLookupAccess(ULE, Best->FoundDecl); 6064 DiagnoseUseOfDecl(Best->FoundDecl, ULE->getNameLoc()); 6065 Fn = FixOverloadedFunctionReference(Fn, Best->FoundDecl, FDecl); 6066 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 6067 } 6068 6069 case OR_No_Viable_Function: 6070 Diag(Fn->getSourceRange().getBegin(), 6071 diag::err_ovl_no_viable_function_in_call) 6072 << ULE->getName() << Fn->getSourceRange(); 6073 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6074 break; 6075 6076 case OR_Ambiguous: 6077 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 6078 << ULE->getName() << Fn->getSourceRange(); 6079 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6080 break; 6081 6082 case OR_Deleted: 6083 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 6084 << Best->Function->isDeleted() 6085 << ULE->getName() 6086 << Fn->getSourceRange(); 6087 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6088 break; 6089 } 6090 6091 // Overload resolution failed. Destroy all of the subexpressions and 6092 // return NULL. 6093 Fn->Destroy(Context); 6094 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 6095 Args[Arg]->Destroy(Context); 6096 return ExprError(); 6097} 6098 6099static bool IsOverloaded(const UnresolvedSetImpl &Functions) { 6100 return Functions.size() > 1 || 6101 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 6102} 6103 6104/// \brief Create a unary operation that may resolve to an overloaded 6105/// operator. 6106/// 6107/// \param OpLoc The location of the operator itself (e.g., '*'). 6108/// 6109/// \param OpcIn The UnaryOperator::Opcode that describes this 6110/// operator. 6111/// 6112/// \param Functions The set of non-member functions that will be 6113/// considered by overload resolution. The caller needs to build this 6114/// set based on the context using, e.g., 6115/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 6116/// set should not contain any member functions; those will be added 6117/// by CreateOverloadedUnaryOp(). 6118/// 6119/// \param input The input argument. 6120Sema::OwningExprResult 6121Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn, 6122 const UnresolvedSetImpl &Fns, 6123 ExprArg input) { 6124 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 6125 Expr *Input = (Expr *)input.get(); 6126 6127 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 6128 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 6129 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 6130 6131 Expr *Args[2] = { Input, 0 }; 6132 unsigned NumArgs = 1; 6133 6134 // For post-increment and post-decrement, add the implicit '0' as 6135 // the second argument, so that we know this is a post-increment or 6136 // post-decrement. 6137 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 6138 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 6139 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 6140 SourceLocation()); 6141 NumArgs = 2; 6142 } 6143 6144 if (Input->isTypeDependent()) { 6145 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6146 UnresolvedLookupExpr *Fn 6147 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6148 0, SourceRange(), OpName, OpLoc, 6149 /*ADL*/ true, IsOverloaded(Fns)); 6150 Fn->addDecls(Fns.begin(), Fns.end()); 6151 6152 input.release(); 6153 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6154 &Args[0], NumArgs, 6155 Context.DependentTy, 6156 OpLoc)); 6157 } 6158 6159 // Build an empty overload set. 6160 OverloadCandidateSet CandidateSet(OpLoc); 6161 6162 // Add the candidates from the given function set. 6163 AddFunctionCandidates(Fns, &Args[0], NumArgs, CandidateSet, false); 6164 6165 // Add operator candidates that are member functions. 6166 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 6167 6168 // Add candidates from ADL. 6169 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6170 Args, NumArgs, 6171 /*ExplicitTemplateArgs*/ 0, 6172 CandidateSet); 6173 6174 // Add builtin operator candidates. 6175 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 6176 6177 // Perform overload resolution. 6178 OverloadCandidateSet::iterator Best; 6179 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6180 case OR_Success: { 6181 // We found a built-in operator or an overloaded operator. 6182 FunctionDecl *FnDecl = Best->Function; 6183 6184 if (FnDecl) { 6185 // We matched an overloaded operator. Build a call to that 6186 // operator. 6187 6188 // Convert the arguments. 6189 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6190 CheckMemberOperatorAccess(OpLoc, Args[0], 0, Best->FoundDecl); 6191 6192 if (PerformObjectArgumentInitialization(Input, /*Qualifier=*/0, 6193 Best->FoundDecl, Method)) 6194 return ExprError(); 6195 } else { 6196 // Convert the arguments. 6197 OwningExprResult InputInit 6198 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6199 FnDecl->getParamDecl(0)), 6200 SourceLocation(), 6201 move(input)); 6202 if (InputInit.isInvalid()) 6203 return ExprError(); 6204 6205 input = move(InputInit); 6206 Input = (Expr *)input.get(); 6207 } 6208 6209 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 6210 6211 // Determine the result type 6212 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 6213 6214 // Build the actual expression node. 6215 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6216 SourceLocation()); 6217 UsualUnaryConversions(FnExpr); 6218 6219 input.release(); 6220 Args[0] = Input; 6221 ExprOwningPtr<CallExpr> TheCall(this, 6222 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6223 Args, NumArgs, ResultTy, OpLoc)); 6224 6225 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6226 FnDecl)) 6227 return ExprError(); 6228 6229 return MaybeBindToTemporary(TheCall.release()); 6230 } else { 6231 // We matched a built-in operator. Convert the arguments, then 6232 // break out so that we will build the appropriate built-in 6233 // operator node. 6234 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 6235 Best->Conversions[0], AA_Passing)) 6236 return ExprError(); 6237 6238 break; 6239 } 6240 } 6241 6242 case OR_No_Viable_Function: 6243 // No viable function; fall through to handling this as a 6244 // built-in operator, which will produce an error message for us. 6245 break; 6246 6247 case OR_Ambiguous: 6248 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6249 << UnaryOperator::getOpcodeStr(Opc) 6250 << Input->getSourceRange(); 6251 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs, 6252 UnaryOperator::getOpcodeStr(Opc), OpLoc); 6253 return ExprError(); 6254 6255 case OR_Deleted: 6256 Diag(OpLoc, diag::err_ovl_deleted_oper) 6257 << Best->Function->isDeleted() 6258 << UnaryOperator::getOpcodeStr(Opc) 6259 << Input->getSourceRange(); 6260 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6261 return ExprError(); 6262 } 6263 6264 // Either we found no viable overloaded operator or we matched a 6265 // built-in operator. In either case, fall through to trying to 6266 // build a built-in operation. 6267 input.release(); 6268 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 6269} 6270 6271/// \brief Create a binary operation that may resolve to an overloaded 6272/// operator. 6273/// 6274/// \param OpLoc The location of the operator itself (e.g., '+'). 6275/// 6276/// \param OpcIn The BinaryOperator::Opcode that describes this 6277/// operator. 6278/// 6279/// \param Functions The set of non-member functions that will be 6280/// considered by overload resolution. The caller needs to build this 6281/// set based on the context using, e.g., 6282/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 6283/// set should not contain any member functions; those will be added 6284/// by CreateOverloadedBinOp(). 6285/// 6286/// \param LHS Left-hand argument. 6287/// \param RHS Right-hand argument. 6288Sema::OwningExprResult 6289Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 6290 unsigned OpcIn, 6291 const UnresolvedSetImpl &Fns, 6292 Expr *LHS, Expr *RHS) { 6293 Expr *Args[2] = { LHS, RHS }; 6294 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 6295 6296 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 6297 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 6298 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 6299 6300 // If either side is type-dependent, create an appropriate dependent 6301 // expression. 6302 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6303 if (Fns.empty()) { 6304 // If there are no functions to store, just build a dependent 6305 // BinaryOperator or CompoundAssignment. 6306 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 6307 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 6308 Context.DependentTy, OpLoc)); 6309 6310 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 6311 Context.DependentTy, 6312 Context.DependentTy, 6313 Context.DependentTy, 6314 OpLoc)); 6315 } 6316 6317 // FIXME: save results of ADL from here? 6318 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6319 UnresolvedLookupExpr *Fn 6320 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6321 0, SourceRange(), OpName, OpLoc, 6322 /*ADL*/ true, IsOverloaded(Fns)); 6323 6324 Fn->addDecls(Fns.begin(), Fns.end()); 6325 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6326 Args, 2, 6327 Context.DependentTy, 6328 OpLoc)); 6329 } 6330 6331 // If this is the .* operator, which is not overloadable, just 6332 // create a built-in binary operator. 6333 if (Opc == BinaryOperator::PtrMemD) 6334 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6335 6336 // If this is the assignment operator, we only perform overload resolution 6337 // if the left-hand side is a class or enumeration type. This is actually 6338 // a hack. The standard requires that we do overload resolution between the 6339 // various built-in candidates, but as DR507 points out, this can lead to 6340 // problems. So we do it this way, which pretty much follows what GCC does. 6341 // Note that we go the traditional code path for compound assignment forms. 6342 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 6343 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6344 6345 // Build an empty overload set. 6346 OverloadCandidateSet CandidateSet(OpLoc); 6347 6348 // Add the candidates from the given function set. 6349 AddFunctionCandidates(Fns, Args, 2, CandidateSet, false); 6350 6351 // Add operator candidates that are member functions. 6352 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6353 6354 // Add candidates from ADL. 6355 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6356 Args, 2, 6357 /*ExplicitTemplateArgs*/ 0, 6358 CandidateSet); 6359 6360 // Add builtin operator candidates. 6361 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6362 6363 // Perform overload resolution. 6364 OverloadCandidateSet::iterator Best; 6365 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6366 case OR_Success: { 6367 // We found a built-in operator or an overloaded operator. 6368 FunctionDecl *FnDecl = Best->Function; 6369 6370 if (FnDecl) { 6371 // We matched an overloaded operator. Build a call to that 6372 // operator. 6373 6374 // Convert the arguments. 6375 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6376 // Best->Access is only meaningful for class members. 6377 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); 6378 6379 OwningExprResult Arg1 6380 = PerformCopyInitialization( 6381 InitializedEntity::InitializeParameter( 6382 FnDecl->getParamDecl(0)), 6383 SourceLocation(), 6384 Owned(Args[1])); 6385 if (Arg1.isInvalid()) 6386 return ExprError(); 6387 6388 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6389 Best->FoundDecl, Method)) 6390 return ExprError(); 6391 6392 Args[1] = RHS = Arg1.takeAs<Expr>(); 6393 } else { 6394 // Convert the arguments. 6395 OwningExprResult Arg0 6396 = PerformCopyInitialization( 6397 InitializedEntity::InitializeParameter( 6398 FnDecl->getParamDecl(0)), 6399 SourceLocation(), 6400 Owned(Args[0])); 6401 if (Arg0.isInvalid()) 6402 return ExprError(); 6403 6404 OwningExprResult Arg1 6405 = PerformCopyInitialization( 6406 InitializedEntity::InitializeParameter( 6407 FnDecl->getParamDecl(1)), 6408 SourceLocation(), 6409 Owned(Args[1])); 6410 if (Arg1.isInvalid()) 6411 return ExprError(); 6412 Args[0] = LHS = Arg0.takeAs<Expr>(); 6413 Args[1] = RHS = Arg1.takeAs<Expr>(); 6414 } 6415 6416 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 6417 6418 // Determine the result type 6419 QualType ResultTy 6420 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6421 ResultTy = ResultTy.getNonReferenceType(); 6422 6423 // Build the actual expression node. 6424 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6425 OpLoc); 6426 UsualUnaryConversions(FnExpr); 6427 6428 ExprOwningPtr<CXXOperatorCallExpr> 6429 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6430 Args, 2, ResultTy, 6431 OpLoc)); 6432 6433 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6434 FnDecl)) 6435 return ExprError(); 6436 6437 return MaybeBindToTemporary(TheCall.release()); 6438 } else { 6439 // We matched a built-in operator. Convert the arguments, then 6440 // break out so that we will build the appropriate built-in 6441 // operator node. 6442 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6443 Best->Conversions[0], AA_Passing) || 6444 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6445 Best->Conversions[1], AA_Passing)) 6446 return ExprError(); 6447 6448 break; 6449 } 6450 } 6451 6452 case OR_No_Viable_Function: { 6453 // C++ [over.match.oper]p9: 6454 // If the operator is the operator , [...] and there are no 6455 // viable functions, then the operator is assumed to be the 6456 // built-in operator and interpreted according to clause 5. 6457 if (Opc == BinaryOperator::Comma) 6458 break; 6459 6460 // For class as left operand for assignment or compound assigment operator 6461 // do not fall through to handling in built-in, but report that no overloaded 6462 // assignment operator found 6463 OwningExprResult Result = ExprError(); 6464 if (Args[0]->getType()->isRecordType() && 6465 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 6466 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6467 << BinaryOperator::getOpcodeStr(Opc) 6468 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6469 } else { 6470 // No viable function; try to create a built-in operation, which will 6471 // produce an error. Then, show the non-viable candidates. 6472 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6473 } 6474 assert(Result.isInvalid() && 6475 "C++ binary operator overloading is missing candidates!"); 6476 if (Result.isInvalid()) 6477 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6478 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6479 return move(Result); 6480 } 6481 6482 case OR_Ambiguous: 6483 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6484 << BinaryOperator::getOpcodeStr(Opc) 6485 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6486 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6487 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6488 return ExprError(); 6489 6490 case OR_Deleted: 6491 Diag(OpLoc, diag::err_ovl_deleted_oper) 6492 << Best->Function->isDeleted() 6493 << BinaryOperator::getOpcodeStr(Opc) 6494 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6495 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2); 6496 return ExprError(); 6497 } 6498 6499 // We matched a built-in operator; build it. 6500 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6501} 6502 6503Action::OwningExprResult 6504Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 6505 SourceLocation RLoc, 6506 ExprArg Base, ExprArg Idx) { 6507 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 6508 static_cast<Expr*>(Idx.get()) }; 6509 DeclarationName OpName = 6510 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 6511 6512 // If either side is type-dependent, create an appropriate dependent 6513 // expression. 6514 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6515 6516 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6517 UnresolvedLookupExpr *Fn 6518 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6519 0, SourceRange(), OpName, LLoc, 6520 /*ADL*/ true, /*Overloaded*/ false); 6521 // Can't add any actual overloads yet 6522 6523 Base.release(); 6524 Idx.release(); 6525 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 6526 Args, 2, 6527 Context.DependentTy, 6528 RLoc)); 6529 } 6530 6531 // Build an empty overload set. 6532 OverloadCandidateSet CandidateSet(LLoc); 6533 6534 // Subscript can only be overloaded as a member function. 6535 6536 // Add operator candidates that are member functions. 6537 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6538 6539 // Add builtin operator candidates. 6540 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6541 6542 // Perform overload resolution. 6543 OverloadCandidateSet::iterator Best; 6544 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 6545 case OR_Success: { 6546 // We found a built-in operator or an overloaded operator. 6547 FunctionDecl *FnDecl = Best->Function; 6548 6549 if (FnDecl) { 6550 // We matched an overloaded operator. Build a call to that 6551 // operator. 6552 6553 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); 6554 DiagnoseUseOfDecl(Best->FoundDecl, LLoc); 6555 6556 // Convert the arguments. 6557 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 6558 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6559 Best->FoundDecl, Method)) 6560 return ExprError(); 6561 6562 // Convert the arguments. 6563 OwningExprResult InputInit 6564 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6565 FnDecl->getParamDecl(0)), 6566 SourceLocation(), 6567 Owned(Args[1])); 6568 if (InputInit.isInvalid()) 6569 return ExprError(); 6570 6571 Args[1] = InputInit.takeAs<Expr>(); 6572 6573 // Determine the result type 6574 QualType ResultTy 6575 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6576 ResultTy = ResultTy.getNonReferenceType(); 6577 6578 // Build the actual expression node. 6579 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6580 LLoc); 6581 UsualUnaryConversions(FnExpr); 6582 6583 Base.release(); 6584 Idx.release(); 6585 ExprOwningPtr<CXXOperatorCallExpr> 6586 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 6587 FnExpr, Args, 2, 6588 ResultTy, RLoc)); 6589 6590 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 6591 FnDecl)) 6592 return ExprError(); 6593 6594 return MaybeBindToTemporary(TheCall.release()); 6595 } else { 6596 // We matched a built-in operator. Convert the arguments, then 6597 // break out so that we will build the appropriate built-in 6598 // operator node. 6599 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6600 Best->Conversions[0], AA_Passing) || 6601 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6602 Best->Conversions[1], AA_Passing)) 6603 return ExprError(); 6604 6605 break; 6606 } 6607 } 6608 6609 case OR_No_Viable_Function: { 6610 if (CandidateSet.empty()) 6611 Diag(LLoc, diag::err_ovl_no_oper) 6612 << Args[0]->getType() << /*subscript*/ 0 6613 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6614 else 6615 Diag(LLoc, diag::err_ovl_no_viable_subscript) 6616 << Args[0]->getType() 6617 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6618 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6619 "[]", LLoc); 6620 return ExprError(); 6621 } 6622 6623 case OR_Ambiguous: 6624 Diag(LLoc, diag::err_ovl_ambiguous_oper) 6625 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6626 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6627 "[]", LLoc); 6628 return ExprError(); 6629 6630 case OR_Deleted: 6631 Diag(LLoc, diag::err_ovl_deleted_oper) 6632 << Best->Function->isDeleted() << "[]" 6633 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6634 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6635 "[]", LLoc); 6636 return ExprError(); 6637 } 6638 6639 // We matched a built-in operator; build it. 6640 Base.release(); 6641 Idx.release(); 6642 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 6643 Owned(Args[1]), RLoc); 6644} 6645 6646/// BuildCallToMemberFunction - Build a call to a member 6647/// function. MemExpr is the expression that refers to the member 6648/// function (and includes the object parameter), Args/NumArgs are the 6649/// arguments to the function call (not including the object 6650/// parameter). The caller needs to validate that the member 6651/// expression refers to a member function or an overloaded member 6652/// function. 6653Sema::OwningExprResult 6654Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 6655 SourceLocation LParenLoc, Expr **Args, 6656 unsigned NumArgs, SourceLocation *CommaLocs, 6657 SourceLocation RParenLoc) { 6658 // Dig out the member expression. This holds both the object 6659 // argument and the member function we're referring to. 6660 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 6661 6662 MemberExpr *MemExpr; 6663 CXXMethodDecl *Method = 0; 6664 DeclAccessPair FoundDecl = DeclAccessPair::make(0, AS_public); 6665 NestedNameSpecifier *Qualifier = 0; 6666 if (isa<MemberExpr>(NakedMemExpr)) { 6667 MemExpr = cast<MemberExpr>(NakedMemExpr); 6668 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 6669 FoundDecl = MemExpr->getFoundDecl(); 6670 Qualifier = MemExpr->getQualifier(); 6671 } else { 6672 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 6673 Qualifier = UnresExpr->getQualifier(); 6674 6675 QualType ObjectType = UnresExpr->getBaseType(); 6676 6677 // Add overload candidates 6678 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc()); 6679 6680 // FIXME: avoid copy. 6681 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6682 if (UnresExpr->hasExplicitTemplateArgs()) { 6683 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6684 TemplateArgs = &TemplateArgsBuffer; 6685 } 6686 6687 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 6688 E = UnresExpr->decls_end(); I != E; ++I) { 6689 6690 NamedDecl *Func = *I; 6691 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 6692 if (isa<UsingShadowDecl>(Func)) 6693 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 6694 6695 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 6696 // If explicit template arguments were provided, we can't call a 6697 // non-template member function. 6698 if (TemplateArgs) 6699 continue; 6700 6701 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, 6702 Args, NumArgs, 6703 CandidateSet, /*SuppressUserConversions=*/false); 6704 } else { 6705 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 6706 I.getPair(), ActingDC, TemplateArgs, 6707 ObjectType, Args, NumArgs, 6708 CandidateSet, 6709 /*SuppressUsedConversions=*/false); 6710 } 6711 } 6712 6713 DeclarationName DeclName = UnresExpr->getMemberName(); 6714 6715 OverloadCandidateSet::iterator Best; 6716 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 6717 case OR_Success: 6718 Method = cast<CXXMethodDecl>(Best->Function); 6719 FoundDecl = Best->FoundDecl; 6720 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); 6721 DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()); 6722 break; 6723 6724 case OR_No_Viable_Function: 6725 Diag(UnresExpr->getMemberLoc(), 6726 diag::err_ovl_no_viable_member_function_in_call) 6727 << DeclName << MemExprE->getSourceRange(); 6728 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6729 // FIXME: Leaking incoming expressions! 6730 return ExprError(); 6731 6732 case OR_Ambiguous: 6733 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 6734 << DeclName << MemExprE->getSourceRange(); 6735 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6736 // FIXME: Leaking incoming expressions! 6737 return ExprError(); 6738 6739 case OR_Deleted: 6740 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 6741 << Best->Function->isDeleted() 6742 << DeclName << MemExprE->getSourceRange(); 6743 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6744 // FIXME: Leaking incoming expressions! 6745 return ExprError(); 6746 } 6747 6748 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); 6749 6750 // If overload resolution picked a static member, build a 6751 // non-member call based on that function. 6752 if (Method->isStatic()) { 6753 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 6754 Args, NumArgs, RParenLoc); 6755 } 6756 6757 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 6758 } 6759 6760 assert(Method && "Member call to something that isn't a method?"); 6761 ExprOwningPtr<CXXMemberCallExpr> 6762 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 6763 NumArgs, 6764 Method->getResultType().getNonReferenceType(), 6765 RParenLoc)); 6766 6767 // Check for a valid return type. 6768 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 6769 TheCall.get(), Method)) 6770 return ExprError(); 6771 6772 // Convert the object argument (for a non-static member function call). 6773 // We only need to do this if there was actually an overload; otherwise 6774 // it was done at lookup. 6775 Expr *ObjectArg = MemExpr->getBase(); 6776 if (!Method->isStatic() && 6777 PerformObjectArgumentInitialization(ObjectArg, Qualifier, 6778 FoundDecl, Method)) 6779 return ExprError(); 6780 MemExpr->setBase(ObjectArg); 6781 6782 // Convert the rest of the arguments 6783 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6784 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 6785 RParenLoc)) 6786 return ExprError(); 6787 6788 if (CheckFunctionCall(Method, TheCall.get())) 6789 return ExprError(); 6790 6791 return MaybeBindToTemporary(TheCall.release()); 6792} 6793 6794/// BuildCallToObjectOfClassType - Build a call to an object of class 6795/// type (C++ [over.call.object]), which can end up invoking an 6796/// overloaded function call operator (@c operator()) or performing a 6797/// user-defined conversion on the object argument. 6798Sema::ExprResult 6799Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 6800 SourceLocation LParenLoc, 6801 Expr **Args, unsigned NumArgs, 6802 SourceLocation *CommaLocs, 6803 SourceLocation RParenLoc) { 6804 assert(Object->getType()->isRecordType() && "Requires object type argument"); 6805 const RecordType *Record = Object->getType()->getAs<RecordType>(); 6806 6807 // C++ [over.call.object]p1: 6808 // If the primary-expression E in the function call syntax 6809 // evaluates to a class object of type "cv T", then the set of 6810 // candidate functions includes at least the function call 6811 // operators of T. The function call operators of T are obtained by 6812 // ordinary lookup of the name operator() in the context of 6813 // (E).operator(). 6814 OverloadCandidateSet CandidateSet(LParenLoc); 6815 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 6816 6817 if (RequireCompleteType(LParenLoc, Object->getType(), 6818 PDiag(diag::err_incomplete_object_call) 6819 << Object->getSourceRange())) 6820 return true; 6821 6822 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 6823 LookupQualifiedName(R, Record->getDecl()); 6824 R.suppressDiagnostics(); 6825 6826 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6827 Oper != OperEnd; ++Oper) { 6828 AddMethodCandidate(Oper.getPair(), Object->getType(), 6829 Args, NumArgs, CandidateSet, 6830 /*SuppressUserConversions=*/ false); 6831 } 6832 6833 // C++ [over.call.object]p2: 6834 // In addition, for each conversion function declared in T of the 6835 // form 6836 // 6837 // operator conversion-type-id () cv-qualifier; 6838 // 6839 // where cv-qualifier is the same cv-qualification as, or a 6840 // greater cv-qualification than, cv, and where conversion-type-id 6841 // denotes the type "pointer to function of (P1,...,Pn) returning 6842 // R", or the type "reference to pointer to function of 6843 // (P1,...,Pn) returning R", or the type "reference to function 6844 // of (P1,...,Pn) returning R", a surrogate call function [...] 6845 // is also considered as a candidate function. Similarly, 6846 // surrogate call functions are added to the set of candidate 6847 // functions for each conversion function declared in an 6848 // accessible base class provided the function is not hidden 6849 // within T by another intervening declaration. 6850 const UnresolvedSetImpl *Conversions 6851 = cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); 6852 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 6853 E = Conversions->end(); I != E; ++I) { 6854 NamedDecl *D = *I; 6855 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 6856 if (isa<UsingShadowDecl>(D)) 6857 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 6858 6859 // Skip over templated conversion functions; they aren't 6860 // surrogates. 6861 if (isa<FunctionTemplateDecl>(D)) 6862 continue; 6863 6864 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 6865 6866 // Strip the reference type (if any) and then the pointer type (if 6867 // any) to get down to what might be a function type. 6868 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 6869 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 6870 ConvType = ConvPtrType->getPointeeType(); 6871 6872 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 6873 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, 6874 Object->getType(), Args, NumArgs, 6875 CandidateSet); 6876 } 6877 6878 // Perform overload resolution. 6879 OverloadCandidateSet::iterator Best; 6880 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 6881 case OR_Success: 6882 // Overload resolution succeeded; we'll build the appropriate call 6883 // below. 6884 break; 6885 6886 case OR_No_Viable_Function: 6887 if (CandidateSet.empty()) 6888 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 6889 << Object->getType() << /*call*/ 1 6890 << Object->getSourceRange(); 6891 else 6892 Diag(Object->getSourceRange().getBegin(), 6893 diag::err_ovl_no_viable_object_call) 6894 << Object->getType() << Object->getSourceRange(); 6895 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6896 break; 6897 6898 case OR_Ambiguous: 6899 Diag(Object->getSourceRange().getBegin(), 6900 diag::err_ovl_ambiguous_object_call) 6901 << Object->getType() << Object->getSourceRange(); 6902 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6903 break; 6904 6905 case OR_Deleted: 6906 Diag(Object->getSourceRange().getBegin(), 6907 diag::err_ovl_deleted_object_call) 6908 << Best->Function->isDeleted() 6909 << Object->getType() << Object->getSourceRange(); 6910 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6911 break; 6912 } 6913 6914 if (Best == CandidateSet.end()) { 6915 // We had an error; delete all of the subexpressions and return 6916 // the error. 6917 Object->Destroy(Context); 6918 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6919 Args[ArgIdx]->Destroy(Context); 6920 return true; 6921 } 6922 6923 if (Best->Function == 0) { 6924 // Since there is no function declaration, this is one of the 6925 // surrogate candidates. Dig out the conversion function. 6926 CXXConversionDecl *Conv 6927 = cast<CXXConversionDecl>( 6928 Best->Conversions[0].UserDefined.ConversionFunction); 6929 6930 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6931 DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc); 6932 6933 // We selected one of the surrogate functions that converts the 6934 // object parameter to a function pointer. Perform the conversion 6935 // on the object argument, then let ActOnCallExpr finish the job. 6936 6937 // Create an implicit member expr to refer to the conversion operator. 6938 // and then call it. 6939 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Best->FoundDecl, 6940 Conv); 6941 6942 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 6943 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 6944 CommaLocs, RParenLoc).result(); 6945 } 6946 6947 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6948 DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc); 6949 6950 // We found an overloaded operator(). Build a CXXOperatorCallExpr 6951 // that calls this method, using Object for the implicit object 6952 // parameter and passing along the remaining arguments. 6953 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6954 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6955 6956 unsigned NumArgsInProto = Proto->getNumArgs(); 6957 unsigned NumArgsToCheck = NumArgs; 6958 6959 // Build the full argument list for the method call (the 6960 // implicit object parameter is placed at the beginning of the 6961 // list). 6962 Expr **MethodArgs; 6963 if (NumArgs < NumArgsInProto) { 6964 NumArgsToCheck = NumArgsInProto; 6965 MethodArgs = new Expr*[NumArgsInProto + 1]; 6966 } else { 6967 MethodArgs = new Expr*[NumArgs + 1]; 6968 } 6969 MethodArgs[0] = Object; 6970 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6971 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 6972 6973 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 6974 SourceLocation()); 6975 UsualUnaryConversions(NewFn); 6976 6977 // Once we've built TheCall, all of the expressions are properly 6978 // owned. 6979 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6980 ExprOwningPtr<CXXOperatorCallExpr> 6981 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 6982 MethodArgs, NumArgs + 1, 6983 ResultTy, RParenLoc)); 6984 delete [] MethodArgs; 6985 6986 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 6987 Method)) 6988 return true; 6989 6990 // We may have default arguments. If so, we need to allocate more 6991 // slots in the call for them. 6992 if (NumArgs < NumArgsInProto) 6993 TheCall->setNumArgs(Context, NumArgsInProto + 1); 6994 else if (NumArgs > NumArgsInProto) 6995 NumArgsToCheck = NumArgsInProto; 6996 6997 bool IsError = false; 6998 6999 // Initialize the implicit object parameter. 7000 IsError |= PerformObjectArgumentInitialization(Object, /*Qualifier=*/0, 7001 Best->FoundDecl, Method); 7002 TheCall->setArg(0, Object); 7003 7004 7005 // Check the argument types. 7006 for (unsigned i = 0; i != NumArgsToCheck; i++) { 7007 Expr *Arg; 7008 if (i < NumArgs) { 7009 Arg = Args[i]; 7010 7011 // Pass the argument. 7012 7013 OwningExprResult InputInit 7014 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 7015 Method->getParamDecl(i)), 7016 SourceLocation(), Owned(Arg)); 7017 7018 IsError |= InputInit.isInvalid(); 7019 Arg = InputInit.takeAs<Expr>(); 7020 } else { 7021 OwningExprResult DefArg 7022 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 7023 if (DefArg.isInvalid()) { 7024 IsError = true; 7025 break; 7026 } 7027 7028 Arg = DefArg.takeAs<Expr>(); 7029 } 7030 7031 TheCall->setArg(i + 1, Arg); 7032 } 7033 7034 // If this is a variadic call, handle args passed through "...". 7035 if (Proto->isVariadic()) { 7036 // Promote the arguments (C99 6.5.2.2p7). 7037 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 7038 Expr *Arg = Args[i]; 7039 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 7040 TheCall->setArg(i + 1, Arg); 7041 } 7042 } 7043 7044 if (IsError) return true; 7045 7046 if (CheckFunctionCall(Method, TheCall.get())) 7047 return true; 7048 7049 return MaybeBindToTemporary(TheCall.release()).result(); 7050} 7051 7052/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 7053/// (if one exists), where @c Base is an expression of class type and 7054/// @c Member is the name of the member we're trying to find. 7055Sema::OwningExprResult 7056Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 7057 Expr *Base = static_cast<Expr *>(BaseIn.get()); 7058 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 7059 7060 SourceLocation Loc = Base->getExprLoc(); 7061 7062 // C++ [over.ref]p1: 7063 // 7064 // [...] An expression x->m is interpreted as (x.operator->())->m 7065 // for a class object x of type T if T::operator->() exists and if 7066 // the operator is selected as the best match function by the 7067 // overload resolution mechanism (13.3). 7068 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 7069 OverloadCandidateSet CandidateSet(Loc); 7070 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 7071 7072 if (RequireCompleteType(Loc, Base->getType(), 7073 PDiag(diag::err_typecheck_incomplete_tag) 7074 << Base->getSourceRange())) 7075 return ExprError(); 7076 7077 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 7078 LookupQualifiedName(R, BaseRecord->getDecl()); 7079 R.suppressDiagnostics(); 7080 7081 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 7082 Oper != OperEnd; ++Oper) { 7083 AddMethodCandidate(Oper.getPair(), Base->getType(), 0, 0, CandidateSet, 7084 /*SuppressUserConversions=*/false); 7085 } 7086 7087 // Perform overload resolution. 7088 OverloadCandidateSet::iterator Best; 7089 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 7090 case OR_Success: 7091 // Overload resolution succeeded; we'll build the call below. 7092 break; 7093 7094 case OR_No_Viable_Function: 7095 if (CandidateSet.empty()) 7096 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 7097 << Base->getType() << Base->getSourceRange(); 7098 else 7099 Diag(OpLoc, diag::err_ovl_no_viable_oper) 7100 << "operator->" << Base->getSourceRange(); 7101 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 7102 return ExprError(); 7103 7104 case OR_Ambiguous: 7105 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 7106 << "->" << Base->getSourceRange(); 7107 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, &Base, 1); 7108 return ExprError(); 7109 7110 case OR_Deleted: 7111 Diag(OpLoc, diag::err_ovl_deleted_oper) 7112 << Best->Function->isDeleted() 7113 << "->" << Base->getSourceRange(); 7114 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 7115 return ExprError(); 7116 } 7117 7118 CheckMemberOperatorAccess(OpLoc, Base, 0, Best->FoundDecl); 7119 DiagnoseUseOfDecl(Best->FoundDecl, OpLoc); 7120 7121 // Convert the object parameter. 7122 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 7123 if (PerformObjectArgumentInitialization(Base, /*Qualifier=*/0, 7124 Best->FoundDecl, Method)) 7125 return ExprError(); 7126 7127 // No concerns about early exits now. 7128 BaseIn.release(); 7129 7130 // Build the operator call. 7131 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 7132 SourceLocation()); 7133 UsualUnaryConversions(FnExpr); 7134 7135 QualType ResultTy = Method->getResultType().getNonReferenceType(); 7136 ExprOwningPtr<CXXOperatorCallExpr> 7137 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 7138 &Base, 1, ResultTy, OpLoc)); 7139 7140 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 7141 Method)) 7142 return ExprError(); 7143 return move(TheCall); 7144} 7145 7146/// FixOverloadedFunctionReference - E is an expression that refers to 7147/// a C++ overloaded function (possibly with some parentheses and 7148/// perhaps a '&' around it). We have resolved the overloaded function 7149/// to the function declaration Fn, so patch up the expression E to 7150/// refer (possibly indirectly) to Fn. Returns the new expr. 7151Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, 7152 FunctionDecl *Fn) { 7153 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 7154 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), 7155 Found, Fn); 7156 if (SubExpr == PE->getSubExpr()) 7157 return PE->Retain(); 7158 7159 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 7160 } 7161 7162 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 7163 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), 7164 Found, Fn); 7165 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 7166 SubExpr->getType()) && 7167 "Implicit cast type cannot be determined from overload"); 7168 if (SubExpr == ICE->getSubExpr()) 7169 return ICE->Retain(); 7170 7171 return new (Context) ImplicitCastExpr(ICE->getType(), 7172 ICE->getCastKind(), 7173 SubExpr, CXXBaseSpecifierArray(), 7174 ICE->isLvalueCast()); 7175 } 7176 7177 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 7178 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 7179 "Can only take the address of an overloaded function"); 7180 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 7181 if (Method->isStatic()) { 7182 // Do nothing: static member functions aren't any different 7183 // from non-member functions. 7184 } else { 7185 // Fix the sub expression, which really has to be an 7186 // UnresolvedLookupExpr holding an overloaded member function 7187 // or template. 7188 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 7189 Found, Fn); 7190 if (SubExpr == UnOp->getSubExpr()) 7191 return UnOp->Retain(); 7192 7193 assert(isa<DeclRefExpr>(SubExpr) 7194 && "fixed to something other than a decl ref"); 7195 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 7196 && "fixed to a member ref with no nested name qualifier"); 7197 7198 // We have taken the address of a pointer to member 7199 // function. Perform the computation here so that we get the 7200 // appropriate pointer to member type. 7201 QualType ClassType 7202 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 7203 QualType MemPtrType 7204 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 7205 7206 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 7207 MemPtrType, UnOp->getOperatorLoc()); 7208 } 7209 } 7210 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 7211 Found, Fn); 7212 if (SubExpr == UnOp->getSubExpr()) 7213 return UnOp->Retain(); 7214 7215 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 7216 Context.getPointerType(SubExpr->getType()), 7217 UnOp->getOperatorLoc()); 7218 } 7219 7220 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 7221 // FIXME: avoid copy. 7222 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 7223 if (ULE->hasExplicitTemplateArgs()) { 7224 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 7225 TemplateArgs = &TemplateArgsBuffer; 7226 } 7227 7228 return DeclRefExpr::Create(Context, 7229 ULE->getQualifier(), 7230 ULE->getQualifierRange(), 7231 Fn, 7232 ULE->getNameLoc(), 7233 Fn->getType(), 7234 TemplateArgs); 7235 } 7236 7237 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 7238 // FIXME: avoid copy. 7239 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 7240 if (MemExpr->hasExplicitTemplateArgs()) { 7241 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 7242 TemplateArgs = &TemplateArgsBuffer; 7243 } 7244 7245 Expr *Base; 7246 7247 // If we're filling in 7248 if (MemExpr->isImplicitAccess()) { 7249 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 7250 return DeclRefExpr::Create(Context, 7251 MemExpr->getQualifier(), 7252 MemExpr->getQualifierRange(), 7253 Fn, 7254 MemExpr->getMemberLoc(), 7255 Fn->getType(), 7256 TemplateArgs); 7257 } else { 7258 SourceLocation Loc = MemExpr->getMemberLoc(); 7259 if (MemExpr->getQualifier()) 7260 Loc = MemExpr->getQualifierRange().getBegin(); 7261 Base = new (Context) CXXThisExpr(Loc, 7262 MemExpr->getBaseType(), 7263 /*isImplicit=*/true); 7264 } 7265 } else 7266 Base = MemExpr->getBase()->Retain(); 7267 7268 return MemberExpr::Create(Context, Base, 7269 MemExpr->isArrow(), 7270 MemExpr->getQualifier(), 7271 MemExpr->getQualifierRange(), 7272 Fn, 7273 Found, 7274 MemExpr->getMemberLoc(), 7275 TemplateArgs, 7276 Fn->getType()); 7277 } 7278 7279 assert(false && "Invalid reference to overloaded function"); 7280 return E->Retain(); 7281} 7282 7283Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 7284 DeclAccessPair Found, 7285 FunctionDecl *Fn) { 7286 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Found, Fn)); 7287} 7288 7289} // end namespace clang 7290