SemaOverload.cpp revision e25a96c0629b6f928d5e8055510789817db827d0
1//===--- SemaOverload.cpp - C++ Overloading ---------------------*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file provides Sema routines for C++ overloading. 11// 12//===----------------------------------------------------------------------===// 13 14#include "Sema.h" 15#include "Lookup.h" 16#include "SemaInit.h" 17#include "clang/Basic/Diagnostic.h" 18#include "clang/Lex/Preprocessor.h" 19#include "clang/AST/ASTContext.h" 20#include "clang/AST/CXXInheritance.h" 21#include "clang/AST/Expr.h" 22#include "clang/AST/ExprCXX.h" 23#include "clang/AST/TypeOrdering.h" 24#include "clang/Basic/PartialDiagnostic.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/STLExtras.h" 27#include <algorithm> 28 29namespace clang { 30 31/// GetConversionCategory - Retrieve the implicit conversion 32/// category corresponding to the given implicit conversion kind. 33ImplicitConversionCategory 34GetConversionCategory(ImplicitConversionKind Kind) { 35 static const ImplicitConversionCategory 36 Category[(int)ICK_Num_Conversion_Kinds] = { 37 ICC_Identity, 38 ICC_Lvalue_Transformation, 39 ICC_Lvalue_Transformation, 40 ICC_Lvalue_Transformation, 41 ICC_Identity, 42 ICC_Qualification_Adjustment, 43 ICC_Promotion, 44 ICC_Promotion, 45 ICC_Promotion, 46 ICC_Conversion, 47 ICC_Conversion, 48 ICC_Conversion, 49 ICC_Conversion, 50 ICC_Conversion, 51 ICC_Conversion, 52 ICC_Conversion, 53 ICC_Conversion, 54 ICC_Conversion, 55 ICC_Conversion 56 }; 57 return Category[(int)Kind]; 58} 59 60/// GetConversionRank - Retrieve the implicit conversion rank 61/// corresponding to the given implicit conversion kind. 62ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) { 63 static const ImplicitConversionRank 64 Rank[(int)ICK_Num_Conversion_Kinds] = { 65 ICR_Exact_Match, 66 ICR_Exact_Match, 67 ICR_Exact_Match, 68 ICR_Exact_Match, 69 ICR_Exact_Match, 70 ICR_Exact_Match, 71 ICR_Promotion, 72 ICR_Promotion, 73 ICR_Promotion, 74 ICR_Conversion, 75 ICR_Conversion, 76 ICR_Conversion, 77 ICR_Conversion, 78 ICR_Conversion, 79 ICR_Conversion, 80 ICR_Conversion, 81 ICR_Conversion, 82 ICR_Conversion, 83 ICR_Complex_Real_Conversion 84 }; 85 return Rank[(int)Kind]; 86} 87 88/// GetImplicitConversionName - Return the name of this kind of 89/// implicit conversion. 90const char* GetImplicitConversionName(ImplicitConversionKind Kind) { 91 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = { 92 "No conversion", 93 "Lvalue-to-rvalue", 94 "Array-to-pointer", 95 "Function-to-pointer", 96 "Noreturn adjustment", 97 "Qualification", 98 "Integral promotion", 99 "Floating point promotion", 100 "Complex promotion", 101 "Integral conversion", 102 "Floating conversion", 103 "Complex conversion", 104 "Floating-integral conversion", 105 "Complex-real conversion", 106 "Pointer conversion", 107 "Pointer-to-member conversion", 108 "Boolean conversion", 109 "Compatible-types conversion", 110 "Derived-to-base conversion" 111 }; 112 return Name[Kind]; 113} 114 115/// StandardConversionSequence - Set the standard conversion 116/// sequence to the identity conversion. 117void StandardConversionSequence::setAsIdentityConversion() { 118 First = ICK_Identity; 119 Second = ICK_Identity; 120 Third = ICK_Identity; 121 DeprecatedStringLiteralToCharPtr = false; 122 ReferenceBinding = false; 123 DirectBinding = false; 124 RRefBinding = false; 125 CopyConstructor = 0; 126} 127 128/// getRank - Retrieve the rank of this standard conversion sequence 129/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 130/// implicit conversions. 131ImplicitConversionRank StandardConversionSequence::getRank() const { 132 ImplicitConversionRank Rank = ICR_Exact_Match; 133 if (GetConversionRank(First) > Rank) 134 Rank = GetConversionRank(First); 135 if (GetConversionRank(Second) > Rank) 136 Rank = GetConversionRank(Second); 137 if (GetConversionRank(Third) > Rank) 138 Rank = GetConversionRank(Third); 139 return Rank; 140} 141 142/// isPointerConversionToBool - Determines whether this conversion is 143/// a conversion of a pointer or pointer-to-member to bool. This is 144/// used as part of the ranking of standard conversion sequences 145/// (C++ 13.3.3.2p4). 146bool StandardConversionSequence::isPointerConversionToBool() const { 147 // Note that FromType has not necessarily been transformed by the 148 // array-to-pointer or function-to-pointer implicit conversions, so 149 // check for their presence as well as checking whether FromType is 150 // a pointer. 151 if (getToType(1)->isBooleanType() && 152 (getFromType()->isPointerType() || getFromType()->isBlockPointerType() || 153 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 154 return true; 155 156 return false; 157} 158 159/// isPointerConversionToVoidPointer - Determines whether this 160/// conversion is a conversion of a pointer to a void pointer. This is 161/// used as part of the ranking of standard conversion sequences (C++ 162/// 13.3.3.2p4). 163bool 164StandardConversionSequence:: 165isPointerConversionToVoidPointer(ASTContext& Context) const { 166 QualType FromType = getFromType(); 167 QualType ToType = getToType(1); 168 169 // Note that FromType has not necessarily been transformed by the 170 // array-to-pointer implicit conversion, so check for its presence 171 // and redo the conversion to get a pointer. 172 if (First == ICK_Array_To_Pointer) 173 FromType = Context.getArrayDecayedType(FromType); 174 175 if (Second == ICK_Pointer_Conversion && FromType->isPointerType()) 176 if (const PointerType* ToPtrType = ToType->getAs<PointerType>()) 177 return ToPtrType->getPointeeType()->isVoidType(); 178 179 return false; 180} 181 182/// DebugPrint - Print this standard conversion sequence to standard 183/// error. Useful for debugging overloading issues. 184void StandardConversionSequence::DebugPrint() const { 185 llvm::raw_ostream &OS = llvm::errs(); 186 bool PrintedSomething = false; 187 if (First != ICK_Identity) { 188 OS << GetImplicitConversionName(First); 189 PrintedSomething = true; 190 } 191 192 if (Second != ICK_Identity) { 193 if (PrintedSomething) { 194 OS << " -> "; 195 } 196 OS << GetImplicitConversionName(Second); 197 198 if (CopyConstructor) { 199 OS << " (by copy constructor)"; 200 } else if (DirectBinding) { 201 OS << " (direct reference binding)"; 202 } else if (ReferenceBinding) { 203 OS << " (reference binding)"; 204 } 205 PrintedSomething = true; 206 } 207 208 if (Third != ICK_Identity) { 209 if (PrintedSomething) { 210 OS << " -> "; 211 } 212 OS << GetImplicitConversionName(Third); 213 PrintedSomething = true; 214 } 215 216 if (!PrintedSomething) { 217 OS << "No conversions required"; 218 } 219} 220 221/// DebugPrint - Print this user-defined conversion sequence to standard 222/// error. Useful for debugging overloading issues. 223void UserDefinedConversionSequence::DebugPrint() const { 224 llvm::raw_ostream &OS = llvm::errs(); 225 if (Before.First || Before.Second || Before.Third) { 226 Before.DebugPrint(); 227 OS << " -> "; 228 } 229 OS << '\'' << ConversionFunction << '\''; 230 if (After.First || After.Second || After.Third) { 231 OS << " -> "; 232 After.DebugPrint(); 233 } 234} 235 236/// DebugPrint - Print this implicit conversion sequence to standard 237/// error. Useful for debugging overloading issues. 238void ImplicitConversionSequence::DebugPrint() const { 239 llvm::raw_ostream &OS = llvm::errs(); 240 switch (ConversionKind) { 241 case StandardConversion: 242 OS << "Standard conversion: "; 243 Standard.DebugPrint(); 244 break; 245 case UserDefinedConversion: 246 OS << "User-defined conversion: "; 247 UserDefined.DebugPrint(); 248 break; 249 case EllipsisConversion: 250 OS << "Ellipsis conversion"; 251 break; 252 case AmbiguousConversion: 253 OS << "Ambiguous conversion"; 254 break; 255 case BadConversion: 256 OS << "Bad conversion"; 257 break; 258 } 259 260 OS << "\n"; 261} 262 263void AmbiguousConversionSequence::construct() { 264 new (&conversions()) ConversionSet(); 265} 266 267void AmbiguousConversionSequence::destruct() { 268 conversions().~ConversionSet(); 269} 270 271void 272AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) { 273 FromTypePtr = O.FromTypePtr; 274 ToTypePtr = O.ToTypePtr; 275 new (&conversions()) ConversionSet(O.conversions()); 276} 277 278 279// IsOverload - Determine whether the given New declaration is an 280// overload of the declarations in Old. This routine returns false if 281// New and Old cannot be overloaded, e.g., if New has the same 282// signature as some function in Old (C++ 1.3.10) or if the Old 283// declarations aren't functions (or function templates) at all. When 284// it does return false, MatchedDecl will point to the decl that New 285// cannot be overloaded with. This decl may be a UsingShadowDecl on 286// top of the underlying declaration. 287// 288// Example: Given the following input: 289// 290// void f(int, float); // #1 291// void f(int, int); // #2 292// int f(int, int); // #3 293// 294// When we process #1, there is no previous declaration of "f", 295// so IsOverload will not be used. 296// 297// When we process #2, Old contains only the FunctionDecl for #1. By 298// comparing the parameter types, we see that #1 and #2 are overloaded 299// (since they have different signatures), so this routine returns 300// false; MatchedDecl is unchanged. 301// 302// When we process #3, Old is an overload set containing #1 and #2. We 303// compare the signatures of #3 to #1 (they're overloaded, so we do 304// nothing) and then #3 to #2. Since the signatures of #3 and #2 are 305// identical (return types of functions are not part of the 306// signature), IsOverload returns false and MatchedDecl will be set to 307// point to the FunctionDecl for #2. 308Sema::OverloadKind 309Sema::CheckOverload(FunctionDecl *New, const LookupResult &Old, 310 NamedDecl *&Match) { 311 for (LookupResult::iterator I = Old.begin(), E = Old.end(); 312 I != E; ++I) { 313 NamedDecl *OldD = (*I)->getUnderlyingDecl(); 314 if (FunctionTemplateDecl *OldT = dyn_cast<FunctionTemplateDecl>(OldD)) { 315 if (!IsOverload(New, OldT->getTemplatedDecl())) { 316 Match = *I; 317 return Ovl_Match; 318 } 319 } else if (FunctionDecl *OldF = dyn_cast<FunctionDecl>(OldD)) { 320 if (!IsOverload(New, OldF)) { 321 Match = *I; 322 return Ovl_Match; 323 } 324 } else if (isa<UsingDecl>(OldD) || isa<TagDecl>(OldD)) { 325 // We can overload with these, which can show up when doing 326 // redeclaration checks for UsingDecls. 327 assert(Old.getLookupKind() == LookupUsingDeclName); 328 } else if (isa<UnresolvedUsingValueDecl>(OldD)) { 329 // Optimistically assume that an unresolved using decl will 330 // overload; if it doesn't, we'll have to diagnose during 331 // template instantiation. 332 } else { 333 // (C++ 13p1): 334 // Only function declarations can be overloaded; object and type 335 // declarations cannot be overloaded. 336 Match = *I; 337 return Ovl_NonFunction; 338 } 339 } 340 341 return Ovl_Overload; 342} 343 344bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old) { 345 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate(); 346 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate(); 347 348 // C++ [temp.fct]p2: 349 // A function template can be overloaded with other function templates 350 // and with normal (non-template) functions. 351 if ((OldTemplate == 0) != (NewTemplate == 0)) 352 return true; 353 354 // Is the function New an overload of the function Old? 355 QualType OldQType = Context.getCanonicalType(Old->getType()); 356 QualType NewQType = Context.getCanonicalType(New->getType()); 357 358 // Compare the signatures (C++ 1.3.10) of the two functions to 359 // determine whether they are overloads. If we find any mismatch 360 // in the signature, they are overloads. 361 362 // If either of these functions is a K&R-style function (no 363 // prototype), then we consider them to have matching signatures. 364 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 365 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 366 return false; 367 368 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType); 369 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType); 370 371 // The signature of a function includes the types of its 372 // parameters (C++ 1.3.10), which includes the presence or absence 373 // of the ellipsis; see C++ DR 357). 374 if (OldQType != NewQType && 375 (OldType->getNumArgs() != NewType->getNumArgs() || 376 OldType->isVariadic() != NewType->isVariadic() || 377 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 378 NewType->arg_type_begin()))) 379 return true; 380 381 // C++ [temp.over.link]p4: 382 // The signature of a function template consists of its function 383 // signature, its return type and its template parameter list. The names 384 // of the template parameters are significant only for establishing the 385 // relationship between the template parameters and the rest of the 386 // signature. 387 // 388 // We check the return type and template parameter lists for function 389 // templates first; the remaining checks follow. 390 if (NewTemplate && 391 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), 392 OldTemplate->getTemplateParameters(), 393 false, TPL_TemplateMatch) || 394 OldType->getResultType() != NewType->getResultType())) 395 return true; 396 397 // If the function is a class member, its signature includes the 398 // cv-qualifiers (if any) on the function itself. 399 // 400 // As part of this, also check whether one of the member functions 401 // is static, in which case they are not overloads (C++ 402 // 13.1p2). While not part of the definition of the signature, 403 // this check is important to determine whether these functions 404 // can be overloaded. 405 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 406 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 407 if (OldMethod && NewMethod && 408 !OldMethod->isStatic() && !NewMethod->isStatic() && 409 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 410 return true; 411 412 // The signatures match; this is not an overload. 413 return false; 414} 415 416/// TryImplicitConversion - Attempt to perform an implicit conversion 417/// from the given expression (Expr) to the given type (ToType). This 418/// function returns an implicit conversion sequence that can be used 419/// to perform the initialization. Given 420/// 421/// void f(float f); 422/// void g(int i) { f(i); } 423/// 424/// this routine would produce an implicit conversion sequence to 425/// describe the initialization of f from i, which will be a standard 426/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 427/// 4.1) followed by a floating-integral conversion (C++ 4.9). 428// 429/// Note that this routine only determines how the conversion can be 430/// performed; it does not actually perform the conversion. As such, 431/// it will not produce any diagnostics if no conversion is available, 432/// but will instead return an implicit conversion sequence of kind 433/// "BadConversion". 434/// 435/// If @p SuppressUserConversions, then user-defined conversions are 436/// not permitted. 437/// If @p AllowExplicit, then explicit user-defined conversions are 438/// permitted. 439ImplicitConversionSequence 440Sema::TryImplicitConversion(Expr* From, QualType ToType, 441 bool SuppressUserConversions, 442 bool AllowExplicit, 443 bool InOverloadResolution) { 444 ImplicitConversionSequence ICS; 445 if (IsStandardConversion(From, ToType, InOverloadResolution, ICS.Standard)) { 446 ICS.setStandard(); 447 return ICS; 448 } 449 450 if (!getLangOptions().CPlusPlus) { 451 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 452 return ICS; 453 } 454 455 if (SuppressUserConversions) { 456 // C++ [over.ics.user]p4: 457 // A conversion of an expression of class type to the same class 458 // type is given Exact Match rank, and a conversion of an 459 // expression of class type to a base class of that type is 460 // given Conversion rank, in spite of the fact that a copy/move 461 // constructor (i.e., a user-defined conversion function) is 462 // called for those cases. 463 QualType FromType = From->getType(); 464 if (!ToType->getAs<RecordType>() || !FromType->getAs<RecordType>() || 465 !(Context.hasSameUnqualifiedType(FromType, ToType) || 466 IsDerivedFrom(FromType, ToType))) { 467 // We're not in the case above, so there is no conversion that 468 // we can perform. 469 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 470 return ICS; 471 } 472 473 ICS.setStandard(); 474 ICS.Standard.setAsIdentityConversion(); 475 ICS.Standard.setFromType(FromType); 476 ICS.Standard.setAllToTypes(ToType); 477 478 // We don't actually check at this point whether there is a valid 479 // copy/move constructor, since overloading just assumes that it 480 // exists. When we actually perform initialization, we'll find the 481 // appropriate constructor to copy the returned object, if needed. 482 ICS.Standard.CopyConstructor = 0; 483 484 // Determine whether this is considered a derived-to-base conversion. 485 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 486 ICS.Standard.Second = ICK_Derived_To_Base; 487 488 return ICS; 489 } 490 491 // Attempt user-defined conversion. 492 OverloadCandidateSet Conversions(From->getExprLoc()); 493 OverloadingResult UserDefResult 494 = IsUserDefinedConversion(From, ToType, ICS.UserDefined, Conversions, 495 AllowExplicit); 496 497 if (UserDefResult == OR_Success) { 498 ICS.setUserDefined(); 499 // C++ [over.ics.user]p4: 500 // A conversion of an expression of class type to the same class 501 // type is given Exact Match rank, and a conversion of an 502 // expression of class type to a base class of that type is 503 // given Conversion rank, in spite of the fact that a copy 504 // constructor (i.e., a user-defined conversion function) is 505 // called for those cases. 506 if (CXXConstructorDecl *Constructor 507 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 508 QualType FromCanon 509 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 510 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 511 if (Constructor->isCopyConstructor() && 512 (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) { 513 // Turn this into a "standard" conversion sequence, so that it 514 // gets ranked with standard conversion sequences. 515 ICS.setStandard(); 516 ICS.Standard.setAsIdentityConversion(); 517 ICS.Standard.setFromType(From->getType()); 518 ICS.Standard.setAllToTypes(ToType); 519 ICS.Standard.CopyConstructor = Constructor; 520 if (ToCanon != FromCanon) 521 ICS.Standard.Second = ICK_Derived_To_Base; 522 } 523 } 524 525 // C++ [over.best.ics]p4: 526 // However, when considering the argument of a user-defined 527 // conversion function that is a candidate by 13.3.1.3 when 528 // invoked for the copying of the temporary in the second step 529 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 530 // 13.3.1.6 in all cases, only standard conversion sequences and 531 // ellipsis conversion sequences are allowed. 532 if (SuppressUserConversions && ICS.isUserDefined()) { 533 ICS.setBad(BadConversionSequence::suppressed_user, From, ToType); 534 } 535 } else if (UserDefResult == OR_Ambiguous && !SuppressUserConversions) { 536 ICS.setAmbiguous(); 537 ICS.Ambiguous.setFromType(From->getType()); 538 ICS.Ambiguous.setToType(ToType); 539 for (OverloadCandidateSet::iterator Cand = Conversions.begin(); 540 Cand != Conversions.end(); ++Cand) 541 if (Cand->Viable) 542 ICS.Ambiguous.addConversion(Cand->Function); 543 } else { 544 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 545 } 546 547 return ICS; 548} 549 550/// PerformImplicitConversion - Perform an implicit conversion of the 551/// expression From to the type ToType. Returns true if there was an 552/// error, false otherwise. The expression From is replaced with the 553/// converted expression. Flavor is the kind of conversion we're 554/// performing, used in the error message. If @p AllowExplicit, 555/// explicit user-defined conversions are permitted. 556bool 557Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 558 AssignmentAction Action, bool AllowExplicit) { 559 ImplicitConversionSequence ICS; 560 return PerformImplicitConversion(From, ToType, Action, AllowExplicit, ICS); 561} 562 563bool 564Sema::PerformImplicitConversion(Expr *&From, QualType ToType, 565 AssignmentAction Action, bool AllowExplicit, 566 ImplicitConversionSequence& ICS) { 567 ICS = TryImplicitConversion(From, ToType, 568 /*SuppressUserConversions=*/false, 569 AllowExplicit, 570 /*InOverloadResolution=*/false); 571 return PerformImplicitConversion(From, ToType, ICS, Action); 572} 573 574/// \brief Determine whether the conversion from FromType to ToType is a valid 575/// conversion that strips "noreturn" off the nested function type. 576static bool IsNoReturnConversion(ASTContext &Context, QualType FromType, 577 QualType ToType, QualType &ResultTy) { 578 if (Context.hasSameUnqualifiedType(FromType, ToType)) 579 return false; 580 581 // Strip the noreturn off the type we're converting from; noreturn can 582 // safely be removed. 583 FromType = Context.getNoReturnType(FromType, false); 584 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 585 return false; 586 587 ResultTy = FromType; 588 return true; 589} 590 591/// IsStandardConversion - Determines whether there is a standard 592/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 593/// expression From to the type ToType. Standard conversion sequences 594/// only consider non-class types; for conversions that involve class 595/// types, use TryImplicitConversion. If a conversion exists, SCS will 596/// contain the standard conversion sequence required to perform this 597/// conversion and this routine will return true. Otherwise, this 598/// routine will return false and the value of SCS is unspecified. 599bool 600Sema::IsStandardConversion(Expr* From, QualType ToType, 601 bool InOverloadResolution, 602 StandardConversionSequence &SCS) { 603 QualType FromType = From->getType(); 604 605 // Standard conversions (C++ [conv]) 606 SCS.setAsIdentityConversion(); 607 SCS.DeprecatedStringLiteralToCharPtr = false; 608 SCS.IncompatibleObjC = false; 609 SCS.setFromType(FromType); 610 SCS.CopyConstructor = 0; 611 612 // There are no standard conversions for class types in C++, so 613 // abort early. When overloading in C, however, we do permit 614 if (FromType->isRecordType() || ToType->isRecordType()) { 615 if (getLangOptions().CPlusPlus) 616 return false; 617 618 // When we're overloading in C, we allow, as standard conversions, 619 } 620 621 // The first conversion can be an lvalue-to-rvalue conversion, 622 // array-to-pointer conversion, or function-to-pointer conversion 623 // (C++ 4p1). 624 625 DeclAccessPair AccessPair; 626 627 // Lvalue-to-rvalue conversion (C++ 4.1): 628 // An lvalue (3.10) of a non-function, non-array type T can be 629 // converted to an rvalue. 630 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 631 if (argIsLvalue == Expr::LV_Valid && 632 !FromType->isFunctionType() && !FromType->isArrayType() && 633 Context.getCanonicalType(FromType) != Context.OverloadTy) { 634 SCS.First = ICK_Lvalue_To_Rvalue; 635 636 // If T is a non-class type, the type of the rvalue is the 637 // cv-unqualified version of T. Otherwise, the type of the rvalue 638 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 639 // just strip the qualifiers because they don't matter. 640 FromType = FromType.getUnqualifiedType(); 641 } else if (FromType->isArrayType()) { 642 // Array-to-pointer conversion (C++ 4.2) 643 SCS.First = ICK_Array_To_Pointer; 644 645 // An lvalue or rvalue of type "array of N T" or "array of unknown 646 // bound of T" can be converted to an rvalue of type "pointer to 647 // T" (C++ 4.2p1). 648 FromType = Context.getArrayDecayedType(FromType); 649 650 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 651 // This conversion is deprecated. (C++ D.4). 652 SCS.DeprecatedStringLiteralToCharPtr = true; 653 654 // For the purpose of ranking in overload resolution 655 // (13.3.3.1.1), this conversion is considered an 656 // array-to-pointer conversion followed by a qualification 657 // conversion (4.4). (C++ 4.2p2) 658 SCS.Second = ICK_Identity; 659 SCS.Third = ICK_Qualification; 660 SCS.setAllToTypes(FromType); 661 return true; 662 } 663 } else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 664 // Function-to-pointer conversion (C++ 4.3). 665 SCS.First = ICK_Function_To_Pointer; 666 667 // An lvalue of function type T can be converted to an rvalue of 668 // type "pointer to T." The result is a pointer to the 669 // function. (C++ 4.3p1). 670 FromType = Context.getPointerType(FromType); 671 } else if (From->getType() == Context.OverloadTy) { 672 if (FunctionDecl *Fn 673 = ResolveAddressOfOverloadedFunction(From, ToType, false, 674 AccessPair)) { 675 // Address of overloaded function (C++ [over.over]). 676 SCS.First = ICK_Function_To_Pointer; 677 678 // We were able to resolve the address of the overloaded function, 679 // so we can convert to the type of that function. 680 FromType = Fn->getType(); 681 if (ToType->isLValueReferenceType()) 682 FromType = Context.getLValueReferenceType(FromType); 683 else if (ToType->isRValueReferenceType()) 684 FromType = Context.getRValueReferenceType(FromType); 685 else if (ToType->isMemberPointerType()) { 686 // Resolve address only succeeds if both sides are member pointers, 687 // but it doesn't have to be the same class. See DR 247. 688 // Note that this means that the type of &Derived::fn can be 689 // Ret (Base::*)(Args) if the fn overload actually found is from the 690 // base class, even if it was brought into the derived class via a 691 // using declaration. The standard isn't clear on this issue at all. 692 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 693 FromType = Context.getMemberPointerType(FromType, 694 Context.getTypeDeclType(M->getParent()).getTypePtr()); 695 } else { 696 FromType = Context.getPointerType(FromType); 697 } 698 } else { 699 return false; 700 } 701 } else { 702 // We don't require any conversions for the first step. 703 SCS.First = ICK_Identity; 704 } 705 SCS.setToType(0, FromType); 706 707 // The second conversion can be an integral promotion, floating 708 // point promotion, integral conversion, floating point conversion, 709 // floating-integral conversion, pointer conversion, 710 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 711 // For overloading in C, this can also be a "compatible-type" 712 // conversion. 713 bool IncompatibleObjC = false; 714 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 715 // The unqualified versions of the types are the same: there's no 716 // conversion to do. 717 SCS.Second = ICK_Identity; 718 } else if (IsIntegralPromotion(From, FromType, ToType)) { 719 // Integral promotion (C++ 4.5). 720 SCS.Second = ICK_Integral_Promotion; 721 FromType = ToType.getUnqualifiedType(); 722 } else if (IsFloatingPointPromotion(FromType, ToType)) { 723 // Floating point promotion (C++ 4.6). 724 SCS.Second = ICK_Floating_Promotion; 725 FromType = ToType.getUnqualifiedType(); 726 } else if (IsComplexPromotion(FromType, ToType)) { 727 // Complex promotion (Clang extension) 728 SCS.Second = ICK_Complex_Promotion; 729 FromType = ToType.getUnqualifiedType(); 730 } else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 731 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 732 // Integral conversions (C++ 4.7). 733 SCS.Second = ICK_Integral_Conversion; 734 FromType = ToType.getUnqualifiedType(); 735 } else if (FromType->isComplexType() && ToType->isComplexType()) { 736 // Complex conversions (C99 6.3.1.6) 737 SCS.Second = ICK_Complex_Conversion; 738 FromType = ToType.getUnqualifiedType(); 739 } else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 740 (ToType->isComplexType() && FromType->isArithmeticType())) { 741 // Complex-real conversions (C99 6.3.1.7) 742 SCS.Second = ICK_Complex_Real; 743 FromType = ToType.getUnqualifiedType(); 744 } else if (FromType->isFloatingType() && ToType->isFloatingType()) { 745 // Floating point conversions (C++ 4.8). 746 SCS.Second = ICK_Floating_Conversion; 747 FromType = ToType.getUnqualifiedType(); 748 } else if ((FromType->isFloatingType() && 749 ToType->isIntegralType() && (!ToType->isBooleanType() && 750 !ToType->isEnumeralType())) || 751 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 752 ToType->isFloatingType())) { 753 // Floating-integral conversions (C++ 4.9). 754 SCS.Second = ICK_Floating_Integral; 755 FromType = ToType.getUnqualifiedType(); 756 } else if (IsPointerConversion(From, FromType, ToType, InOverloadResolution, 757 FromType, IncompatibleObjC)) { 758 // Pointer conversions (C++ 4.10). 759 SCS.Second = ICK_Pointer_Conversion; 760 SCS.IncompatibleObjC = IncompatibleObjC; 761 } else if (IsMemberPointerConversion(From, FromType, ToType, 762 InOverloadResolution, FromType)) { 763 // Pointer to member conversions (4.11). 764 SCS.Second = ICK_Pointer_Member; 765 } else if (ToType->isBooleanType() && 766 (FromType->isArithmeticType() || 767 FromType->isEnumeralType() || 768 FromType->isAnyPointerType() || 769 FromType->isBlockPointerType() || 770 FromType->isMemberPointerType() || 771 FromType->isNullPtrType())) { 772 // Boolean conversions (C++ 4.12). 773 SCS.Second = ICK_Boolean_Conversion; 774 FromType = Context.BoolTy; 775 } else if (!getLangOptions().CPlusPlus && 776 Context.typesAreCompatible(ToType, FromType)) { 777 // Compatible conversions (Clang extension for C function overloading) 778 SCS.Second = ICK_Compatible_Conversion; 779 } else if (IsNoReturnConversion(Context, FromType, ToType, FromType)) { 780 // Treat a conversion that strips "noreturn" as an identity conversion. 781 SCS.Second = ICK_NoReturn_Adjustment; 782 } else { 783 // No second conversion required. 784 SCS.Second = ICK_Identity; 785 } 786 SCS.setToType(1, FromType); 787 788 QualType CanonFrom; 789 QualType CanonTo; 790 // The third conversion can be a qualification conversion (C++ 4p1). 791 if (IsQualificationConversion(FromType, ToType)) { 792 SCS.Third = ICK_Qualification; 793 FromType = ToType; 794 CanonFrom = Context.getCanonicalType(FromType); 795 CanonTo = Context.getCanonicalType(ToType); 796 } else { 797 // No conversion required 798 SCS.Third = ICK_Identity; 799 800 // C++ [over.best.ics]p6: 801 // [...] Any difference in top-level cv-qualification is 802 // subsumed by the initialization itself and does not constitute 803 // a conversion. [...] 804 CanonFrom = Context.getCanonicalType(FromType); 805 CanonTo = Context.getCanonicalType(ToType); 806 if (CanonFrom.getLocalUnqualifiedType() 807 == CanonTo.getLocalUnqualifiedType() && 808 CanonFrom.getLocalCVRQualifiers() != CanonTo.getLocalCVRQualifiers()) { 809 FromType = ToType; 810 CanonFrom = CanonTo; 811 } 812 } 813 SCS.setToType(2, FromType); 814 815 // If we have not converted the argument type to the parameter type, 816 // this is a bad conversion sequence. 817 if (CanonFrom != CanonTo) 818 return false; 819 820 return true; 821} 822 823/// IsIntegralPromotion - Determines whether the conversion from the 824/// expression From (whose potentially-adjusted type is FromType) to 825/// ToType is an integral promotion (C++ 4.5). If so, returns true and 826/// sets PromotedType to the promoted type. 827bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { 828 const BuiltinType *To = ToType->getAs<BuiltinType>(); 829 // All integers are built-in. 830 if (!To) { 831 return false; 832 } 833 834 // An rvalue of type char, signed char, unsigned char, short int, or 835 // unsigned short int can be converted to an rvalue of type int if 836 // int can represent all the values of the source type; otherwise, 837 // the source rvalue can be converted to an rvalue of type unsigned 838 // int (C++ 4.5p1). 839 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && 840 !FromType->isEnumeralType()) { 841 if (// We can promote any signed, promotable integer type to an int 842 (FromType->isSignedIntegerType() || 843 // We can promote any unsigned integer type whose size is 844 // less than int to an int. 845 (!FromType->isSignedIntegerType() && 846 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 847 return To->getKind() == BuiltinType::Int; 848 } 849 850 return To->getKind() == BuiltinType::UInt; 851 } 852 853 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 854 // can be converted to an rvalue of the first of the following types 855 // that can represent all the values of its underlying type: int, 856 // unsigned int, long, or unsigned long (C++ 4.5p2). 857 858 // We pre-calculate the promotion type for enum types. 859 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) 860 if (ToType->isIntegerType()) 861 return Context.hasSameUnqualifiedType(ToType, 862 FromEnumType->getDecl()->getPromotionType()); 863 864 if (FromType->isWideCharType() && ToType->isIntegerType()) { 865 // Determine whether the type we're converting from is signed or 866 // unsigned. 867 bool FromIsSigned; 868 uint64_t FromSize = Context.getTypeSize(FromType); 869 870 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 871 FromIsSigned = true; 872 873 // The types we'll try to promote to, in the appropriate 874 // order. Try each of these types. 875 QualType PromoteTypes[6] = { 876 Context.IntTy, Context.UnsignedIntTy, 877 Context.LongTy, Context.UnsignedLongTy , 878 Context.LongLongTy, Context.UnsignedLongLongTy 879 }; 880 for (int Idx = 0; Idx < 6; ++Idx) { 881 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 882 if (FromSize < ToSize || 883 (FromSize == ToSize && 884 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 885 // We found the type that we can promote to. If this is the 886 // type we wanted, we have a promotion. Otherwise, no 887 // promotion. 888 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); 889 } 890 } 891 } 892 893 // An rvalue for an integral bit-field (9.6) can be converted to an 894 // rvalue of type int if int can represent all the values of the 895 // bit-field; otherwise, it can be converted to unsigned int if 896 // unsigned int can represent all the values of the bit-field. If 897 // the bit-field is larger yet, no integral promotion applies to 898 // it. If the bit-field has an enumerated type, it is treated as any 899 // other value of that type for promotion purposes (C++ 4.5p3). 900 // FIXME: We should delay checking of bit-fields until we actually perform the 901 // conversion. 902 using llvm::APSInt; 903 if (From) 904 if (FieldDecl *MemberDecl = From->getBitField()) { 905 APSInt BitWidth; 906 if (FromType->isIntegralType() && !FromType->isEnumeralType() && 907 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { 908 APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned()); 909 ToSize = Context.getTypeSize(ToType); 910 911 // Are we promoting to an int from a bitfield that fits in an int? 912 if (BitWidth < ToSize || 913 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 914 return To->getKind() == BuiltinType::Int; 915 } 916 917 // Are we promoting to an unsigned int from an unsigned bitfield 918 // that fits into an unsigned int? 919 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 920 return To->getKind() == BuiltinType::UInt; 921 } 922 923 return false; 924 } 925 } 926 927 // An rvalue of type bool can be converted to an rvalue of type int, 928 // with false becoming zero and true becoming one (C++ 4.5p4). 929 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 930 return true; 931 } 932 933 return false; 934} 935 936/// IsFloatingPointPromotion - Determines whether the conversion from 937/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 938/// returns true and sets PromotedType to the promoted type. 939bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { 940 /// An rvalue of type float can be converted to an rvalue of type 941 /// double. (C++ 4.6p1). 942 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) 943 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { 944 if (FromBuiltin->getKind() == BuiltinType::Float && 945 ToBuiltin->getKind() == BuiltinType::Double) 946 return true; 947 948 // C99 6.3.1.5p1: 949 // When a float is promoted to double or long double, or a 950 // double is promoted to long double [...]. 951 if (!getLangOptions().CPlusPlus && 952 (FromBuiltin->getKind() == BuiltinType::Float || 953 FromBuiltin->getKind() == BuiltinType::Double) && 954 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 955 return true; 956 } 957 958 return false; 959} 960 961/// \brief Determine if a conversion is a complex promotion. 962/// 963/// A complex promotion is defined as a complex -> complex conversion 964/// where the conversion between the underlying real types is a 965/// floating-point or integral promotion. 966bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 967 const ComplexType *FromComplex = FromType->getAs<ComplexType>(); 968 if (!FromComplex) 969 return false; 970 971 const ComplexType *ToComplex = ToType->getAs<ComplexType>(); 972 if (!ToComplex) 973 return false; 974 975 return IsFloatingPointPromotion(FromComplex->getElementType(), 976 ToComplex->getElementType()) || 977 IsIntegralPromotion(0, FromComplex->getElementType(), 978 ToComplex->getElementType()); 979} 980 981/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 982/// the pointer type FromPtr to a pointer to type ToPointee, with the 983/// same type qualifiers as FromPtr has on its pointee type. ToType, 984/// if non-empty, will be a pointer to ToType that may or may not have 985/// the right set of qualifiers on its pointee. 986static QualType 987BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 988 QualType ToPointee, QualType ToType, 989 ASTContext &Context) { 990 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 991 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 992 Qualifiers Quals = CanonFromPointee.getQualifiers(); 993 994 // Exact qualifier match -> return the pointer type we're converting to. 995 if (CanonToPointee.getLocalQualifiers() == Quals) { 996 // ToType is exactly what we need. Return it. 997 if (!ToType.isNull()) 998 return ToType; 999 1000 // Build a pointer to ToPointee. It has the right qualifiers 1001 // already. 1002 return Context.getPointerType(ToPointee); 1003 } 1004 1005 // Just build a canonical type that has the right qualifiers. 1006 return Context.getPointerType( 1007 Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), 1008 Quals)); 1009} 1010 1011/// BuildSimilarlyQualifiedObjCObjectPointerType - In a pointer conversion from 1012/// the FromType, which is an objective-c pointer, to ToType, which may or may 1013/// not have the right set of qualifiers. 1014static QualType 1015BuildSimilarlyQualifiedObjCObjectPointerType(QualType FromType, 1016 QualType ToType, 1017 ASTContext &Context) { 1018 QualType CanonFromType = Context.getCanonicalType(FromType); 1019 QualType CanonToType = Context.getCanonicalType(ToType); 1020 Qualifiers Quals = CanonFromType.getQualifiers(); 1021 1022 // Exact qualifier match -> return the pointer type we're converting to. 1023 if (CanonToType.getLocalQualifiers() == Quals) 1024 return ToType; 1025 1026 // Just build a canonical type that has the right qualifiers. 1027 return Context.getQualifiedType(CanonToType.getLocalUnqualifiedType(), Quals); 1028} 1029 1030static bool isNullPointerConstantForConversion(Expr *Expr, 1031 bool InOverloadResolution, 1032 ASTContext &Context) { 1033 // Handle value-dependent integral null pointer constants correctly. 1034 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 1035 if (Expr->isValueDependent() && !Expr->isTypeDependent() && 1036 Expr->getType()->isIntegralType()) 1037 return !InOverloadResolution; 1038 1039 return Expr->isNullPointerConstant(Context, 1040 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1041 : Expr::NPC_ValueDependentIsNull); 1042} 1043 1044/// IsPointerConversion - Determines whether the conversion of the 1045/// expression From, which has the (possibly adjusted) type FromType, 1046/// can be converted to the type ToType via a pointer conversion (C++ 1047/// 4.10). If so, returns true and places the converted type (that 1048/// might differ from ToType in its cv-qualifiers at some level) into 1049/// ConvertedType. 1050/// 1051/// This routine also supports conversions to and from block pointers 1052/// and conversions with Objective-C's 'id', 'id<protocols...>', and 1053/// pointers to interfaces. FIXME: Once we've determined the 1054/// appropriate overloading rules for Objective-C, we may want to 1055/// split the Objective-C checks into a different routine; however, 1056/// GCC seems to consider all of these conversions to be pointer 1057/// conversions, so for now they live here. IncompatibleObjC will be 1058/// set if the conversion is an allowed Objective-C conversion that 1059/// should result in a warning. 1060bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 1061 bool InOverloadResolution, 1062 QualType& ConvertedType, 1063 bool &IncompatibleObjC) { 1064 IncompatibleObjC = false; 1065 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 1066 return true; 1067 1068 // Conversion from a null pointer constant to any Objective-C pointer type. 1069 if (ToType->isObjCObjectPointerType() && 1070 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1071 ConvertedType = ToType; 1072 return true; 1073 } 1074 1075 // Blocks: Block pointers can be converted to void*. 1076 if (FromType->isBlockPointerType() && ToType->isPointerType() && 1077 ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) { 1078 ConvertedType = ToType; 1079 return true; 1080 } 1081 // Blocks: A null pointer constant can be converted to a block 1082 // pointer type. 1083 if (ToType->isBlockPointerType() && 1084 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1085 ConvertedType = ToType; 1086 return true; 1087 } 1088 1089 // If the left-hand-side is nullptr_t, the right side can be a null 1090 // pointer constant. 1091 if (ToType->isNullPtrType() && 1092 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1093 ConvertedType = ToType; 1094 return true; 1095 } 1096 1097 const PointerType* ToTypePtr = ToType->getAs<PointerType>(); 1098 if (!ToTypePtr) 1099 return false; 1100 1101 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 1102 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1103 ConvertedType = ToType; 1104 return true; 1105 } 1106 1107 // Beyond this point, both types need to be pointers 1108 // , including objective-c pointers. 1109 QualType ToPointeeType = ToTypePtr->getPointeeType(); 1110 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType()) { 1111 ConvertedType = BuildSimilarlyQualifiedObjCObjectPointerType(FromType, 1112 ToType, Context); 1113 return true; 1114 1115 } 1116 const PointerType *FromTypePtr = FromType->getAs<PointerType>(); 1117 if (!FromTypePtr) 1118 return false; 1119 1120 QualType FromPointeeType = FromTypePtr->getPointeeType(); 1121 1122 // An rvalue of type "pointer to cv T," where T is an object type, 1123 // can be converted to an rvalue of type "pointer to cv void" (C++ 1124 // 4.10p2). 1125 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 1126 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1127 ToPointeeType, 1128 ToType, Context); 1129 return true; 1130 } 1131 1132 // When we're overloading in C, we allow a special kind of pointer 1133 // conversion for compatible-but-not-identical pointee types. 1134 if (!getLangOptions().CPlusPlus && 1135 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 1136 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1137 ToPointeeType, 1138 ToType, Context); 1139 return true; 1140 } 1141 1142 // C++ [conv.ptr]p3: 1143 // 1144 // An rvalue of type "pointer to cv D," where D is a class type, 1145 // can be converted to an rvalue of type "pointer to cv B," where 1146 // B is a base class (clause 10) of D. If B is an inaccessible 1147 // (clause 11) or ambiguous (10.2) base class of D, a program that 1148 // necessitates this conversion is ill-formed. The result of the 1149 // conversion is a pointer to the base class sub-object of the 1150 // derived class object. The null pointer value is converted to 1151 // the null pointer value of the destination type. 1152 // 1153 // Note that we do not check for ambiguity or inaccessibility 1154 // here. That is handled by CheckPointerConversion. 1155 if (getLangOptions().CPlusPlus && 1156 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1157 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && 1158 !RequireCompleteType(From->getLocStart(), FromPointeeType, PDiag()) && 1159 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 1160 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1161 ToPointeeType, 1162 ToType, Context); 1163 return true; 1164 } 1165 1166 return false; 1167} 1168 1169/// isObjCPointerConversion - Determines whether this is an 1170/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 1171/// with the same arguments and return values. 1172bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 1173 QualType& ConvertedType, 1174 bool &IncompatibleObjC) { 1175 if (!getLangOptions().ObjC1) 1176 return false; 1177 1178 // First, we handle all conversions on ObjC object pointer types. 1179 const ObjCObjectPointerType* ToObjCPtr = ToType->getAs<ObjCObjectPointerType>(); 1180 const ObjCObjectPointerType *FromObjCPtr = 1181 FromType->getAs<ObjCObjectPointerType>(); 1182 1183 if (ToObjCPtr && FromObjCPtr) { 1184 // Objective C++: We're able to convert between "id" or "Class" and a 1185 // pointer to any interface (in both directions). 1186 if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) { 1187 ConvertedType = ToType; 1188 return true; 1189 } 1190 // Conversions with Objective-C's id<...>. 1191 if ((FromObjCPtr->isObjCQualifiedIdType() || 1192 ToObjCPtr->isObjCQualifiedIdType()) && 1193 Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType, 1194 /*compare=*/false)) { 1195 ConvertedType = ToType; 1196 return true; 1197 } 1198 // Objective C++: We're able to convert from a pointer to an 1199 // interface to a pointer to a different interface. 1200 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { 1201 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); 1202 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); 1203 if (getLangOptions().CPlusPlus && LHS && RHS && 1204 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( 1205 FromObjCPtr->getPointeeType())) 1206 return false; 1207 ConvertedType = ToType; 1208 return true; 1209 } 1210 1211 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { 1212 // Okay: this is some kind of implicit downcast of Objective-C 1213 // interfaces, which is permitted. However, we're going to 1214 // complain about it. 1215 IncompatibleObjC = true; 1216 ConvertedType = FromType; 1217 return true; 1218 } 1219 } 1220 // Beyond this point, both types need to be C pointers or block pointers. 1221 QualType ToPointeeType; 1222 if (const PointerType *ToCPtr = ToType->getAs<PointerType>()) 1223 ToPointeeType = ToCPtr->getPointeeType(); 1224 else if (const BlockPointerType *ToBlockPtr = 1225 ToType->getAs<BlockPointerType>()) { 1226 // Objective C++: We're able to convert from a pointer to any object 1227 // to a block pointer type. 1228 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { 1229 ConvertedType = ToType; 1230 return true; 1231 } 1232 ToPointeeType = ToBlockPtr->getPointeeType(); 1233 } 1234 else if (FromType->getAs<BlockPointerType>() && 1235 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { 1236 // Objective C++: We're able to convert from a block pointer type to a 1237 // pointer to any object. 1238 ConvertedType = ToType; 1239 return true; 1240 } 1241 else 1242 return false; 1243 1244 QualType FromPointeeType; 1245 if (const PointerType *FromCPtr = FromType->getAs<PointerType>()) 1246 FromPointeeType = FromCPtr->getPointeeType(); 1247 else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>()) 1248 FromPointeeType = FromBlockPtr->getPointeeType(); 1249 else 1250 return false; 1251 1252 // If we have pointers to pointers, recursively check whether this 1253 // is an Objective-C conversion. 1254 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1255 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1256 IncompatibleObjC)) { 1257 // We always complain about this conversion. 1258 IncompatibleObjC = true; 1259 ConvertedType = ToType; 1260 return true; 1261 } 1262 // Allow conversion of pointee being objective-c pointer to another one; 1263 // as in I* to id. 1264 if (FromPointeeType->getAs<ObjCObjectPointerType>() && 1265 ToPointeeType->getAs<ObjCObjectPointerType>() && 1266 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1267 IncompatibleObjC)) { 1268 ConvertedType = ToType; 1269 return true; 1270 } 1271 1272 // If we have pointers to functions or blocks, check whether the only 1273 // differences in the argument and result types are in Objective-C 1274 // pointer conversions. If so, we permit the conversion (but 1275 // complain about it). 1276 const FunctionProtoType *FromFunctionType 1277 = FromPointeeType->getAs<FunctionProtoType>(); 1278 const FunctionProtoType *ToFunctionType 1279 = ToPointeeType->getAs<FunctionProtoType>(); 1280 if (FromFunctionType && ToFunctionType) { 1281 // If the function types are exactly the same, this isn't an 1282 // Objective-C pointer conversion. 1283 if (Context.getCanonicalType(FromPointeeType) 1284 == Context.getCanonicalType(ToPointeeType)) 1285 return false; 1286 1287 // Perform the quick checks that will tell us whether these 1288 // function types are obviously different. 1289 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1290 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1291 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1292 return false; 1293 1294 bool HasObjCConversion = false; 1295 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1296 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1297 // Okay, the types match exactly. Nothing to do. 1298 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1299 ToFunctionType->getResultType(), 1300 ConvertedType, IncompatibleObjC)) { 1301 // Okay, we have an Objective-C pointer conversion. 1302 HasObjCConversion = true; 1303 } else { 1304 // Function types are too different. Abort. 1305 return false; 1306 } 1307 1308 // Check argument types. 1309 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1310 ArgIdx != NumArgs; ++ArgIdx) { 1311 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1312 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1313 if (Context.getCanonicalType(FromArgType) 1314 == Context.getCanonicalType(ToArgType)) { 1315 // Okay, the types match exactly. Nothing to do. 1316 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1317 ConvertedType, IncompatibleObjC)) { 1318 // Okay, we have an Objective-C pointer conversion. 1319 HasObjCConversion = true; 1320 } else { 1321 // Argument types are too different. Abort. 1322 return false; 1323 } 1324 } 1325 1326 if (HasObjCConversion) { 1327 // We had an Objective-C conversion. Allow this pointer 1328 // conversion, but complain about it. 1329 ConvertedType = ToType; 1330 IncompatibleObjC = true; 1331 return true; 1332 } 1333 } 1334 1335 return false; 1336} 1337 1338/// CheckPointerConversion - Check the pointer conversion from the 1339/// expression From to the type ToType. This routine checks for 1340/// ambiguous or inaccessible derived-to-base pointer 1341/// conversions for which IsPointerConversion has already returned 1342/// true. It returns true and produces a diagnostic if there was an 1343/// error, or returns false otherwise. 1344bool Sema::CheckPointerConversion(Expr *From, QualType ToType, 1345 CastExpr::CastKind &Kind, 1346 bool IgnoreBaseAccess) { 1347 QualType FromType = From->getType(); 1348 1349 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) 1350 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { 1351 QualType FromPointeeType = FromPtrType->getPointeeType(), 1352 ToPointeeType = ToPtrType->getPointeeType(); 1353 1354 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1355 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { 1356 // We must have a derived-to-base conversion. Check an 1357 // ambiguous or inaccessible conversion. 1358 if (CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1359 From->getExprLoc(), 1360 From->getSourceRange(), 0, 1361 IgnoreBaseAccess)) 1362 return true; 1363 1364 // The conversion was successful. 1365 Kind = CastExpr::CK_DerivedToBase; 1366 } 1367 } 1368 if (const ObjCObjectPointerType *FromPtrType = 1369 FromType->getAs<ObjCObjectPointerType>()) 1370 if (const ObjCObjectPointerType *ToPtrType = 1371 ToType->getAs<ObjCObjectPointerType>()) { 1372 // Objective-C++ conversions are always okay. 1373 // FIXME: We should have a different class of conversions for the 1374 // Objective-C++ implicit conversions. 1375 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) 1376 return false; 1377 1378 } 1379 return false; 1380} 1381 1382/// IsMemberPointerConversion - Determines whether the conversion of the 1383/// expression From, which has the (possibly adjusted) type FromType, can be 1384/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1385/// If so, returns true and places the converted type (that might differ from 1386/// ToType in its cv-qualifiers at some level) into ConvertedType. 1387bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1388 QualType ToType, 1389 bool InOverloadResolution, 1390 QualType &ConvertedType) { 1391 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>(); 1392 if (!ToTypePtr) 1393 return false; 1394 1395 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1396 if (From->isNullPointerConstant(Context, 1397 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1398 : Expr::NPC_ValueDependentIsNull)) { 1399 ConvertedType = ToType; 1400 return true; 1401 } 1402 1403 // Otherwise, both types have to be member pointers. 1404 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>(); 1405 if (!FromTypePtr) 1406 return false; 1407 1408 // A pointer to member of B can be converted to a pointer to member of D, 1409 // where D is derived from B (C++ 4.11p2). 1410 QualType FromClass(FromTypePtr->getClass(), 0); 1411 QualType ToClass(ToTypePtr->getClass(), 0); 1412 // FIXME: What happens when these are dependent? Is this function even called? 1413 1414 if (IsDerivedFrom(ToClass, FromClass)) { 1415 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1416 ToClass.getTypePtr()); 1417 return true; 1418 } 1419 1420 return false; 1421} 1422 1423/// CheckMemberPointerConversion - Check the member pointer conversion from the 1424/// expression From to the type ToType. This routine checks for ambiguous or 1425/// virtual or inaccessible base-to-derived member pointer conversions 1426/// for which IsMemberPointerConversion has already returned true. It returns 1427/// true and produces a diagnostic if there was an error, or returns false 1428/// otherwise. 1429bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, 1430 CastExpr::CastKind &Kind, 1431 bool IgnoreBaseAccess) { 1432 QualType FromType = From->getType(); 1433 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); 1434 if (!FromPtrType) { 1435 // This must be a null pointer to member pointer conversion 1436 assert(From->isNullPointerConstant(Context, 1437 Expr::NPC_ValueDependentIsNull) && 1438 "Expr must be null pointer constant!"); 1439 Kind = CastExpr::CK_NullToMemberPointer; 1440 return false; 1441 } 1442 1443 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>(); 1444 assert(ToPtrType && "No member pointer cast has a target type " 1445 "that is not a member pointer."); 1446 1447 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1448 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1449 1450 // FIXME: What about dependent types? 1451 assert(FromClass->isRecordType() && "Pointer into non-class."); 1452 assert(ToClass->isRecordType() && "Pointer into non-class."); 1453 1454 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/ true, 1455 /*DetectVirtual=*/true); 1456 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1457 assert(DerivationOkay && 1458 "Should not have been called if derivation isn't OK."); 1459 (void)DerivationOkay; 1460 1461 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1462 getUnqualifiedType())) { 1463 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1464 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1465 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1466 return true; 1467 } 1468 1469 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1470 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1471 << FromClass << ToClass << QualType(VBase, 0) 1472 << From->getSourceRange(); 1473 return true; 1474 } 1475 1476 if (!IgnoreBaseAccess) 1477 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, 1478 Paths.front(), 1479 diag::err_downcast_from_inaccessible_base); 1480 1481 // Must be a base to derived member conversion. 1482 Kind = CastExpr::CK_BaseToDerivedMemberPointer; 1483 return false; 1484} 1485 1486/// IsQualificationConversion - Determines whether the conversion from 1487/// an rvalue of type FromType to ToType is a qualification conversion 1488/// (C++ 4.4). 1489bool 1490Sema::IsQualificationConversion(QualType FromType, QualType ToType) { 1491 FromType = Context.getCanonicalType(FromType); 1492 ToType = Context.getCanonicalType(ToType); 1493 1494 // If FromType and ToType are the same type, this is not a 1495 // qualification conversion. 1496 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) 1497 return false; 1498 1499 // (C++ 4.4p4): 1500 // A conversion can add cv-qualifiers at levels other than the first 1501 // in multi-level pointers, subject to the following rules: [...] 1502 bool PreviousToQualsIncludeConst = true; 1503 bool UnwrappedAnyPointer = false; 1504 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1505 // Within each iteration of the loop, we check the qualifiers to 1506 // determine if this still looks like a qualification 1507 // conversion. Then, if all is well, we unwrap one more level of 1508 // pointers or pointers-to-members and do it all again 1509 // until there are no more pointers or pointers-to-members left to 1510 // unwrap. 1511 UnwrappedAnyPointer = true; 1512 1513 // -- for every j > 0, if const is in cv 1,j then const is in cv 1514 // 2,j, and similarly for volatile. 1515 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1516 return false; 1517 1518 // -- if the cv 1,j and cv 2,j are different, then const is in 1519 // every cv for 0 < k < j. 1520 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1521 && !PreviousToQualsIncludeConst) 1522 return false; 1523 1524 // Keep track of whether all prior cv-qualifiers in the "to" type 1525 // include const. 1526 PreviousToQualsIncludeConst 1527 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1528 } 1529 1530 // We are left with FromType and ToType being the pointee types 1531 // after unwrapping the original FromType and ToType the same number 1532 // of types. If we unwrapped any pointers, and if FromType and 1533 // ToType have the same unqualified type (since we checked 1534 // qualifiers above), then this is a qualification conversion. 1535 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); 1536} 1537 1538/// Determines whether there is a user-defined conversion sequence 1539/// (C++ [over.ics.user]) that converts expression From to the type 1540/// ToType. If such a conversion exists, User will contain the 1541/// user-defined conversion sequence that performs such a conversion 1542/// and this routine will return true. Otherwise, this routine returns 1543/// false and User is unspecified. 1544/// 1545/// \param AllowExplicit true if the conversion should consider C++0x 1546/// "explicit" conversion functions as well as non-explicit conversion 1547/// functions (C++0x [class.conv.fct]p2). 1548OverloadingResult Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1549 UserDefinedConversionSequence& User, 1550 OverloadCandidateSet& CandidateSet, 1551 bool AllowExplicit) { 1552 // Whether we will only visit constructors. 1553 bool ConstructorsOnly = false; 1554 1555 // If the type we are conversion to is a class type, enumerate its 1556 // constructors. 1557 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { 1558 // C++ [over.match.ctor]p1: 1559 // When objects of class type are direct-initialized (8.5), or 1560 // copy-initialized from an expression of the same or a 1561 // derived class type (8.5), overload resolution selects the 1562 // constructor. [...] For copy-initialization, the candidate 1563 // functions are all the converting constructors (12.3.1) of 1564 // that class. The argument list is the expression-list within 1565 // the parentheses of the initializer. 1566 if (Context.hasSameUnqualifiedType(ToType, From->getType()) || 1567 (From->getType()->getAs<RecordType>() && 1568 IsDerivedFrom(From->getType(), ToType))) 1569 ConstructorsOnly = true; 1570 1571 if (RequireCompleteType(From->getLocStart(), ToType, PDiag())) { 1572 // We're not going to find any constructors. 1573 } else if (CXXRecordDecl *ToRecordDecl 1574 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1575 DeclarationName ConstructorName 1576 = Context.DeclarationNames.getCXXConstructorName( 1577 Context.getCanonicalType(ToType).getUnqualifiedType()); 1578 DeclContext::lookup_iterator Con, ConEnd; 1579 for (llvm::tie(Con, ConEnd) 1580 = ToRecordDecl->lookup(ConstructorName); 1581 Con != ConEnd; ++Con) { 1582 NamedDecl *D = *Con; 1583 DeclAccessPair FoundDecl = DeclAccessPair::make(D, D->getAccess()); 1584 1585 // Find the constructor (which may be a template). 1586 CXXConstructorDecl *Constructor = 0; 1587 FunctionTemplateDecl *ConstructorTmpl 1588 = dyn_cast<FunctionTemplateDecl>(D); 1589 if (ConstructorTmpl) 1590 Constructor 1591 = cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl()); 1592 else 1593 Constructor = cast<CXXConstructorDecl>(D); 1594 1595 if (!Constructor->isInvalidDecl() && 1596 Constructor->isConvertingConstructor(AllowExplicit)) { 1597 if (ConstructorTmpl) 1598 AddTemplateOverloadCandidate(ConstructorTmpl, FoundDecl, 1599 /*ExplicitArgs*/ 0, 1600 &From, 1, CandidateSet, 1601 /*SuppressUserConversions=*/!ConstructorsOnly); 1602 else 1603 // Allow one user-defined conversion when user specifies a 1604 // From->ToType conversion via an static cast (c-style, etc). 1605 AddOverloadCandidate(Constructor, FoundDecl, 1606 &From, 1, CandidateSet, 1607 /*SuppressUserConversions=*/!ConstructorsOnly); 1608 } 1609 } 1610 } 1611 } 1612 1613 // Enumerate conversion functions, if we're allowed to. 1614 if (ConstructorsOnly) { 1615 } else if (RequireCompleteType(From->getLocStart(), From->getType(), 1616 PDiag(0) << From->getSourceRange())) { 1617 // No conversion functions from incomplete types. 1618 } else if (const RecordType *FromRecordType 1619 = From->getType()->getAs<RecordType>()) { 1620 if (CXXRecordDecl *FromRecordDecl 1621 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1622 // Add all of the conversion functions as candidates. 1623 const UnresolvedSetImpl *Conversions 1624 = FromRecordDecl->getVisibleConversionFunctions(); 1625 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 1626 E = Conversions->end(); I != E; ++I) { 1627 DeclAccessPair FoundDecl = I.getPair(); 1628 NamedDecl *D = FoundDecl.getDecl(); 1629 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 1630 if (isa<UsingShadowDecl>(D)) 1631 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 1632 1633 CXXConversionDecl *Conv; 1634 FunctionTemplateDecl *ConvTemplate; 1635 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) 1636 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 1637 else 1638 Conv = cast<CXXConversionDecl>(D); 1639 1640 if (AllowExplicit || !Conv->isExplicit()) { 1641 if (ConvTemplate) 1642 AddTemplateConversionCandidate(ConvTemplate, FoundDecl, 1643 ActingContext, From, ToType, 1644 CandidateSet); 1645 else 1646 AddConversionCandidate(Conv, FoundDecl, ActingContext, 1647 From, ToType, CandidateSet); 1648 } 1649 } 1650 } 1651 } 1652 1653 OverloadCandidateSet::iterator Best; 1654 switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) { 1655 case OR_Success: 1656 // Record the standard conversion we used and the conversion function. 1657 if (CXXConstructorDecl *Constructor 1658 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1659 // C++ [over.ics.user]p1: 1660 // If the user-defined conversion is specified by a 1661 // constructor (12.3.1), the initial standard conversion 1662 // sequence converts the source type to the type required by 1663 // the argument of the constructor. 1664 // 1665 QualType ThisType = Constructor->getThisType(Context); 1666 if (Best->Conversions[0].isEllipsis()) 1667 User.EllipsisConversion = true; 1668 else { 1669 User.Before = Best->Conversions[0].Standard; 1670 User.EllipsisConversion = false; 1671 } 1672 User.ConversionFunction = Constructor; 1673 User.After.setAsIdentityConversion(); 1674 User.After.setFromType( 1675 ThisType->getAs<PointerType>()->getPointeeType()); 1676 User.After.setAllToTypes(ToType); 1677 return OR_Success; 1678 } else if (CXXConversionDecl *Conversion 1679 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1680 // C++ [over.ics.user]p1: 1681 // 1682 // [...] If the user-defined conversion is specified by a 1683 // conversion function (12.3.2), the initial standard 1684 // conversion sequence converts the source type to the 1685 // implicit object parameter of the conversion function. 1686 User.Before = Best->Conversions[0].Standard; 1687 User.ConversionFunction = Conversion; 1688 User.EllipsisConversion = false; 1689 1690 // C++ [over.ics.user]p2: 1691 // The second standard conversion sequence converts the 1692 // result of the user-defined conversion to the target type 1693 // for the sequence. Since an implicit conversion sequence 1694 // is an initialization, the special rules for 1695 // initialization by user-defined conversion apply when 1696 // selecting the best user-defined conversion for a 1697 // user-defined conversion sequence (see 13.3.3 and 1698 // 13.3.3.1). 1699 User.After = Best->FinalConversion; 1700 return OR_Success; 1701 } else { 1702 assert(false && "Not a constructor or conversion function?"); 1703 return OR_No_Viable_Function; 1704 } 1705 1706 case OR_No_Viable_Function: 1707 return OR_No_Viable_Function; 1708 case OR_Deleted: 1709 // No conversion here! We're done. 1710 return OR_Deleted; 1711 1712 case OR_Ambiguous: 1713 return OR_Ambiguous; 1714 } 1715 1716 return OR_No_Viable_Function; 1717} 1718 1719bool 1720Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { 1721 ImplicitConversionSequence ICS; 1722 OverloadCandidateSet CandidateSet(From->getExprLoc()); 1723 OverloadingResult OvResult = 1724 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 1725 CandidateSet, false); 1726 if (OvResult == OR_Ambiguous) 1727 Diag(From->getSourceRange().getBegin(), 1728 diag::err_typecheck_ambiguous_condition) 1729 << From->getType() << ToType << From->getSourceRange(); 1730 else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) 1731 Diag(From->getSourceRange().getBegin(), 1732 diag::err_typecheck_nonviable_condition) 1733 << From->getType() << ToType << From->getSourceRange(); 1734 else 1735 return false; 1736 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &From, 1); 1737 return true; 1738} 1739 1740/// CompareImplicitConversionSequences - Compare two implicit 1741/// conversion sequences to determine whether one is better than the 1742/// other or if they are indistinguishable (C++ 13.3.3.2). 1743ImplicitConversionSequence::CompareKind 1744Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1745 const ImplicitConversionSequence& ICS2) 1746{ 1747 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1748 // conversion sequences (as defined in 13.3.3.1) 1749 // -- a standard conversion sequence (13.3.3.1.1) is a better 1750 // conversion sequence than a user-defined conversion sequence or 1751 // an ellipsis conversion sequence, and 1752 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1753 // conversion sequence than an ellipsis conversion sequence 1754 // (13.3.3.1.3). 1755 // 1756 // C++0x [over.best.ics]p10: 1757 // For the purpose of ranking implicit conversion sequences as 1758 // described in 13.3.3.2, the ambiguous conversion sequence is 1759 // treated as a user-defined sequence that is indistinguishable 1760 // from any other user-defined conversion sequence. 1761 if (ICS1.getKindRank() < ICS2.getKindRank()) 1762 return ImplicitConversionSequence::Better; 1763 else if (ICS2.getKindRank() < ICS1.getKindRank()) 1764 return ImplicitConversionSequence::Worse; 1765 1766 // The following checks require both conversion sequences to be of 1767 // the same kind. 1768 if (ICS1.getKind() != ICS2.getKind()) 1769 return ImplicitConversionSequence::Indistinguishable; 1770 1771 // Two implicit conversion sequences of the same form are 1772 // indistinguishable conversion sequences unless one of the 1773 // following rules apply: (C++ 13.3.3.2p3): 1774 if (ICS1.isStandard()) 1775 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1776 else if (ICS1.isUserDefined()) { 1777 // User-defined conversion sequence U1 is a better conversion 1778 // sequence than another user-defined conversion sequence U2 if 1779 // they contain the same user-defined conversion function or 1780 // constructor and if the second standard conversion sequence of 1781 // U1 is better than the second standard conversion sequence of 1782 // U2 (C++ 13.3.3.2p3). 1783 if (ICS1.UserDefined.ConversionFunction == 1784 ICS2.UserDefined.ConversionFunction) 1785 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1786 ICS2.UserDefined.After); 1787 } 1788 1789 return ImplicitConversionSequence::Indistinguishable; 1790} 1791 1792// Per 13.3.3.2p3, compare the given standard conversion sequences to 1793// determine if one is a proper subset of the other. 1794static ImplicitConversionSequence::CompareKind 1795compareStandardConversionSubsets(ASTContext &Context, 1796 const StandardConversionSequence& SCS1, 1797 const StandardConversionSequence& SCS2) { 1798 ImplicitConversionSequence::CompareKind Result 1799 = ImplicitConversionSequence::Indistinguishable; 1800 1801 if (SCS1.Second != SCS2.Second) { 1802 if (SCS1.Second == ICK_Identity) 1803 Result = ImplicitConversionSequence::Better; 1804 else if (SCS2.Second == ICK_Identity) 1805 Result = ImplicitConversionSequence::Worse; 1806 else 1807 return ImplicitConversionSequence::Indistinguishable; 1808 } else if (!Context.hasSameType(SCS1.getToType(1), SCS2.getToType(1))) 1809 return ImplicitConversionSequence::Indistinguishable; 1810 1811 if (SCS1.Third == SCS2.Third) { 1812 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result 1813 : ImplicitConversionSequence::Indistinguishable; 1814 } 1815 1816 if (SCS1.Third == ICK_Identity) 1817 return Result == ImplicitConversionSequence::Worse 1818 ? ImplicitConversionSequence::Indistinguishable 1819 : ImplicitConversionSequence::Better; 1820 1821 if (SCS2.Third == ICK_Identity) 1822 return Result == ImplicitConversionSequence::Better 1823 ? ImplicitConversionSequence::Indistinguishable 1824 : ImplicitConversionSequence::Worse; 1825 1826 return ImplicitConversionSequence::Indistinguishable; 1827} 1828 1829/// CompareStandardConversionSequences - Compare two standard 1830/// conversion sequences to determine whether one is better than the 1831/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1832ImplicitConversionSequence::CompareKind 1833Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1834 const StandardConversionSequence& SCS2) 1835{ 1836 // Standard conversion sequence S1 is a better conversion sequence 1837 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1838 1839 // -- S1 is a proper subsequence of S2 (comparing the conversion 1840 // sequences in the canonical form defined by 13.3.3.1.1, 1841 // excluding any Lvalue Transformation; the identity conversion 1842 // sequence is considered to be a subsequence of any 1843 // non-identity conversion sequence) or, if not that, 1844 if (ImplicitConversionSequence::CompareKind CK 1845 = compareStandardConversionSubsets(Context, SCS1, SCS2)) 1846 return CK; 1847 1848 // -- the rank of S1 is better than the rank of S2 (by the rules 1849 // defined below), or, if not that, 1850 ImplicitConversionRank Rank1 = SCS1.getRank(); 1851 ImplicitConversionRank Rank2 = SCS2.getRank(); 1852 if (Rank1 < Rank2) 1853 return ImplicitConversionSequence::Better; 1854 else if (Rank2 < Rank1) 1855 return ImplicitConversionSequence::Worse; 1856 1857 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1858 // are indistinguishable unless one of the following rules 1859 // applies: 1860 1861 // A conversion that is not a conversion of a pointer, or 1862 // pointer to member, to bool is better than another conversion 1863 // that is such a conversion. 1864 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1865 return SCS2.isPointerConversionToBool() 1866 ? ImplicitConversionSequence::Better 1867 : ImplicitConversionSequence::Worse; 1868 1869 // C++ [over.ics.rank]p4b2: 1870 // 1871 // If class B is derived directly or indirectly from class A, 1872 // conversion of B* to A* is better than conversion of B* to 1873 // void*, and conversion of A* to void* is better than conversion 1874 // of B* to void*. 1875 bool SCS1ConvertsToVoid 1876 = SCS1.isPointerConversionToVoidPointer(Context); 1877 bool SCS2ConvertsToVoid 1878 = SCS2.isPointerConversionToVoidPointer(Context); 1879 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1880 // Exactly one of the conversion sequences is a conversion to 1881 // a void pointer; it's the worse conversion. 1882 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1883 : ImplicitConversionSequence::Worse; 1884 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1885 // Neither conversion sequence converts to a void pointer; compare 1886 // their derived-to-base conversions. 1887 if (ImplicitConversionSequence::CompareKind DerivedCK 1888 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1889 return DerivedCK; 1890 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1891 // Both conversion sequences are conversions to void 1892 // pointers. Compare the source types to determine if there's an 1893 // inheritance relationship in their sources. 1894 QualType FromType1 = SCS1.getFromType(); 1895 QualType FromType2 = SCS2.getFromType(); 1896 1897 // Adjust the types we're converting from via the array-to-pointer 1898 // conversion, if we need to. 1899 if (SCS1.First == ICK_Array_To_Pointer) 1900 FromType1 = Context.getArrayDecayedType(FromType1); 1901 if (SCS2.First == ICK_Array_To_Pointer) 1902 FromType2 = Context.getArrayDecayedType(FromType2); 1903 1904 QualType FromPointee1 1905 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1906 QualType FromPointee2 1907 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1908 1909 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1910 return ImplicitConversionSequence::Better; 1911 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1912 return ImplicitConversionSequence::Worse; 1913 1914 // Objective-C++: If one interface is more specific than the 1915 // other, it is the better one. 1916 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 1917 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 1918 if (FromIface1 && FromIface1) { 1919 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1920 return ImplicitConversionSequence::Better; 1921 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1922 return ImplicitConversionSequence::Worse; 1923 } 1924 } 1925 1926 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1927 // bullet 3). 1928 if (ImplicitConversionSequence::CompareKind QualCK 1929 = CompareQualificationConversions(SCS1, SCS2)) 1930 return QualCK; 1931 1932 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1933 // C++0x [over.ics.rank]p3b4: 1934 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 1935 // implicit object parameter of a non-static member function declared 1936 // without a ref-qualifier, and S1 binds an rvalue reference to an 1937 // rvalue and S2 binds an lvalue reference. 1938 // FIXME: We don't know if we're dealing with the implicit object parameter, 1939 // or if the member function in this case has a ref qualifier. 1940 // (Of course, we don't have ref qualifiers yet.) 1941 if (SCS1.RRefBinding != SCS2.RRefBinding) 1942 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 1943 : ImplicitConversionSequence::Worse; 1944 1945 // C++ [over.ics.rank]p3b4: 1946 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1947 // which the references refer are the same type except for 1948 // top-level cv-qualifiers, and the type to which the reference 1949 // initialized by S2 refers is more cv-qualified than the type 1950 // to which the reference initialized by S1 refers. 1951 QualType T1 = SCS1.getToType(2); 1952 QualType T2 = SCS2.getToType(2); 1953 T1 = Context.getCanonicalType(T1); 1954 T2 = Context.getCanonicalType(T2); 1955 Qualifiers T1Quals, T2Quals; 1956 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1957 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1958 if (UnqualT1 == UnqualT2) { 1959 // If the type is an array type, promote the element qualifiers to the type 1960 // for comparison. 1961 if (isa<ArrayType>(T1) && T1Quals) 1962 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 1963 if (isa<ArrayType>(T2) && T2Quals) 1964 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 1965 if (T2.isMoreQualifiedThan(T1)) 1966 return ImplicitConversionSequence::Better; 1967 else if (T1.isMoreQualifiedThan(T2)) 1968 return ImplicitConversionSequence::Worse; 1969 } 1970 } 1971 1972 return ImplicitConversionSequence::Indistinguishable; 1973} 1974 1975/// CompareQualificationConversions - Compares two standard conversion 1976/// sequences to determine whether they can be ranked based on their 1977/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1978ImplicitConversionSequence::CompareKind 1979Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1980 const StandardConversionSequence& SCS2) { 1981 // C++ 13.3.3.2p3: 1982 // -- S1 and S2 differ only in their qualification conversion and 1983 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1984 // cv-qualification signature of type T1 is a proper subset of 1985 // the cv-qualification signature of type T2, and S1 is not the 1986 // deprecated string literal array-to-pointer conversion (4.2). 1987 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1988 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1989 return ImplicitConversionSequence::Indistinguishable; 1990 1991 // FIXME: the example in the standard doesn't use a qualification 1992 // conversion (!) 1993 QualType T1 = SCS1.getToType(2); 1994 QualType T2 = SCS2.getToType(2); 1995 T1 = Context.getCanonicalType(T1); 1996 T2 = Context.getCanonicalType(T2); 1997 Qualifiers T1Quals, T2Quals; 1998 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1999 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2000 2001 // If the types are the same, we won't learn anything by unwrapped 2002 // them. 2003 if (UnqualT1 == UnqualT2) 2004 return ImplicitConversionSequence::Indistinguishable; 2005 2006 // If the type is an array type, promote the element qualifiers to the type 2007 // for comparison. 2008 if (isa<ArrayType>(T1) && T1Quals) 2009 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2010 if (isa<ArrayType>(T2) && T2Quals) 2011 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2012 2013 ImplicitConversionSequence::CompareKind Result 2014 = ImplicitConversionSequence::Indistinguishable; 2015 while (UnwrapSimilarPointerTypes(T1, T2)) { 2016 // Within each iteration of the loop, we check the qualifiers to 2017 // determine if this still looks like a qualification 2018 // conversion. Then, if all is well, we unwrap one more level of 2019 // pointers or pointers-to-members and do it all again 2020 // until there are no more pointers or pointers-to-members left 2021 // to unwrap. This essentially mimics what 2022 // IsQualificationConversion does, but here we're checking for a 2023 // strict subset of qualifiers. 2024 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 2025 // The qualifiers are the same, so this doesn't tell us anything 2026 // about how the sequences rank. 2027 ; 2028 else if (T2.isMoreQualifiedThan(T1)) { 2029 // T1 has fewer qualifiers, so it could be the better sequence. 2030 if (Result == ImplicitConversionSequence::Worse) 2031 // Neither has qualifiers that are a subset of the other's 2032 // qualifiers. 2033 return ImplicitConversionSequence::Indistinguishable; 2034 2035 Result = ImplicitConversionSequence::Better; 2036 } else if (T1.isMoreQualifiedThan(T2)) { 2037 // T2 has fewer qualifiers, so it could be the better sequence. 2038 if (Result == ImplicitConversionSequence::Better) 2039 // Neither has qualifiers that are a subset of the other's 2040 // qualifiers. 2041 return ImplicitConversionSequence::Indistinguishable; 2042 2043 Result = ImplicitConversionSequence::Worse; 2044 } else { 2045 // Qualifiers are disjoint. 2046 return ImplicitConversionSequence::Indistinguishable; 2047 } 2048 2049 // If the types after this point are equivalent, we're done. 2050 if (Context.hasSameUnqualifiedType(T1, T2)) 2051 break; 2052 } 2053 2054 // Check that the winning standard conversion sequence isn't using 2055 // the deprecated string literal array to pointer conversion. 2056 switch (Result) { 2057 case ImplicitConversionSequence::Better: 2058 if (SCS1.DeprecatedStringLiteralToCharPtr) 2059 Result = ImplicitConversionSequence::Indistinguishable; 2060 break; 2061 2062 case ImplicitConversionSequence::Indistinguishable: 2063 break; 2064 2065 case ImplicitConversionSequence::Worse: 2066 if (SCS2.DeprecatedStringLiteralToCharPtr) 2067 Result = ImplicitConversionSequence::Indistinguishable; 2068 break; 2069 } 2070 2071 return Result; 2072} 2073 2074/// CompareDerivedToBaseConversions - Compares two standard conversion 2075/// sequences to determine whether they can be ranked based on their 2076/// various kinds of derived-to-base conversions (C++ 2077/// [over.ics.rank]p4b3). As part of these checks, we also look at 2078/// conversions between Objective-C interface types. 2079ImplicitConversionSequence::CompareKind 2080Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 2081 const StandardConversionSequence& SCS2) { 2082 QualType FromType1 = SCS1.getFromType(); 2083 QualType ToType1 = SCS1.getToType(1); 2084 QualType FromType2 = SCS2.getFromType(); 2085 QualType ToType2 = SCS2.getToType(1); 2086 2087 // Adjust the types we're converting from via the array-to-pointer 2088 // conversion, if we need to. 2089 if (SCS1.First == ICK_Array_To_Pointer) 2090 FromType1 = Context.getArrayDecayedType(FromType1); 2091 if (SCS2.First == ICK_Array_To_Pointer) 2092 FromType2 = Context.getArrayDecayedType(FromType2); 2093 2094 // Canonicalize all of the types. 2095 FromType1 = Context.getCanonicalType(FromType1); 2096 ToType1 = Context.getCanonicalType(ToType1); 2097 FromType2 = Context.getCanonicalType(FromType2); 2098 ToType2 = Context.getCanonicalType(ToType2); 2099 2100 // C++ [over.ics.rank]p4b3: 2101 // 2102 // If class B is derived directly or indirectly from class A and 2103 // class C is derived directly or indirectly from B, 2104 // 2105 // For Objective-C, we let A, B, and C also be Objective-C 2106 // interfaces. 2107 2108 // Compare based on pointer conversions. 2109 if (SCS1.Second == ICK_Pointer_Conversion && 2110 SCS2.Second == ICK_Pointer_Conversion && 2111 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 2112 FromType1->isPointerType() && FromType2->isPointerType() && 2113 ToType1->isPointerType() && ToType2->isPointerType()) { 2114 QualType FromPointee1 2115 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2116 QualType ToPointee1 2117 = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2118 QualType FromPointee2 2119 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2120 QualType ToPointee2 2121 = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2122 2123 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 2124 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 2125 const ObjCInterfaceType* ToIface1 = ToPointee1->getAs<ObjCInterfaceType>(); 2126 const ObjCInterfaceType* ToIface2 = ToPointee2->getAs<ObjCInterfaceType>(); 2127 2128 // -- conversion of C* to B* is better than conversion of C* to A*, 2129 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2130 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2131 return ImplicitConversionSequence::Better; 2132 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2133 return ImplicitConversionSequence::Worse; 2134 2135 if (ToIface1 && ToIface2) { 2136 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 2137 return ImplicitConversionSequence::Better; 2138 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 2139 return ImplicitConversionSequence::Worse; 2140 } 2141 } 2142 2143 // -- conversion of B* to A* is better than conversion of C* to A*, 2144 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 2145 if (IsDerivedFrom(FromPointee2, FromPointee1)) 2146 return ImplicitConversionSequence::Better; 2147 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 2148 return ImplicitConversionSequence::Worse; 2149 2150 if (FromIface1 && FromIface2) { 2151 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2152 return ImplicitConversionSequence::Better; 2153 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2154 return ImplicitConversionSequence::Worse; 2155 } 2156 } 2157 } 2158 2159 // Ranking of member-pointer types. 2160 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && 2161 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && 2162 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { 2163 const MemberPointerType * FromMemPointer1 = 2164 FromType1->getAs<MemberPointerType>(); 2165 const MemberPointerType * ToMemPointer1 = 2166 ToType1->getAs<MemberPointerType>(); 2167 const MemberPointerType * FromMemPointer2 = 2168 FromType2->getAs<MemberPointerType>(); 2169 const MemberPointerType * ToMemPointer2 = 2170 ToType2->getAs<MemberPointerType>(); 2171 const Type *FromPointeeType1 = FromMemPointer1->getClass(); 2172 const Type *ToPointeeType1 = ToMemPointer1->getClass(); 2173 const Type *FromPointeeType2 = FromMemPointer2->getClass(); 2174 const Type *ToPointeeType2 = ToMemPointer2->getClass(); 2175 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); 2176 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); 2177 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); 2178 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); 2179 // conversion of A::* to B::* is better than conversion of A::* to C::*, 2180 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2181 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2182 return ImplicitConversionSequence::Worse; 2183 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2184 return ImplicitConversionSequence::Better; 2185 } 2186 // conversion of B::* to C::* is better than conversion of A::* to C::* 2187 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { 2188 if (IsDerivedFrom(FromPointee1, FromPointee2)) 2189 return ImplicitConversionSequence::Better; 2190 else if (IsDerivedFrom(FromPointee2, FromPointee1)) 2191 return ImplicitConversionSequence::Worse; 2192 } 2193 } 2194 2195 if (SCS1.Second == ICK_Derived_To_Base) { 2196 // -- conversion of C to B is better than conversion of C to A, 2197 // -- binding of an expression of type C to a reference of type 2198 // B& is better than binding an expression of type C to a 2199 // reference of type A&, 2200 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2201 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2202 if (IsDerivedFrom(ToType1, ToType2)) 2203 return ImplicitConversionSequence::Better; 2204 else if (IsDerivedFrom(ToType2, ToType1)) 2205 return ImplicitConversionSequence::Worse; 2206 } 2207 2208 // -- conversion of B to A is better than conversion of C to A. 2209 // -- binding of an expression of type B to a reference of type 2210 // A& is better than binding an expression of type C to a 2211 // reference of type A&, 2212 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2213 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2214 if (IsDerivedFrom(FromType2, FromType1)) 2215 return ImplicitConversionSequence::Better; 2216 else if (IsDerivedFrom(FromType1, FromType2)) 2217 return ImplicitConversionSequence::Worse; 2218 } 2219 } 2220 2221 return ImplicitConversionSequence::Indistinguishable; 2222} 2223 2224/// CompareReferenceRelationship - Compare the two types T1 and T2 to 2225/// determine whether they are reference-related, 2226/// reference-compatible, reference-compatible with added 2227/// qualification, or incompatible, for use in C++ initialization by 2228/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 2229/// type, and the first type (T1) is the pointee type of the reference 2230/// type being initialized. 2231Sema::ReferenceCompareResult 2232Sema::CompareReferenceRelationship(SourceLocation Loc, 2233 QualType OrigT1, QualType OrigT2, 2234 bool& DerivedToBase) { 2235 assert(!OrigT1->isReferenceType() && 2236 "T1 must be the pointee type of the reference type"); 2237 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); 2238 2239 QualType T1 = Context.getCanonicalType(OrigT1); 2240 QualType T2 = Context.getCanonicalType(OrigT2); 2241 Qualifiers T1Quals, T2Quals; 2242 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2243 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2244 2245 // C++ [dcl.init.ref]p4: 2246 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is 2247 // reference-related to "cv2 T2" if T1 is the same type as T2, or 2248 // T1 is a base class of T2. 2249 if (UnqualT1 == UnqualT2) 2250 DerivedToBase = false; 2251 else if (!RequireCompleteType(Loc, OrigT1, PDiag()) && 2252 !RequireCompleteType(Loc, OrigT2, PDiag()) && 2253 IsDerivedFrom(UnqualT2, UnqualT1)) 2254 DerivedToBase = true; 2255 else 2256 return Ref_Incompatible; 2257 2258 // At this point, we know that T1 and T2 are reference-related (at 2259 // least). 2260 2261 // If the type is an array type, promote the element qualifiers to the type 2262 // for comparison. 2263 if (isa<ArrayType>(T1) && T1Quals) 2264 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2265 if (isa<ArrayType>(T2) && T2Quals) 2266 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2267 2268 // C++ [dcl.init.ref]p4: 2269 // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is 2270 // reference-related to T2 and cv1 is the same cv-qualification 2271 // as, or greater cv-qualification than, cv2. For purposes of 2272 // overload resolution, cases for which cv1 is greater 2273 // cv-qualification than cv2 are identified as 2274 // reference-compatible with added qualification (see 13.3.3.2). 2275 if (T1Quals.getCVRQualifiers() == T2Quals.getCVRQualifiers()) 2276 return Ref_Compatible; 2277 else if (T1.isMoreQualifiedThan(T2)) 2278 return Ref_Compatible_With_Added_Qualification; 2279 else 2280 return Ref_Related; 2281} 2282 2283/// \brief Compute an implicit conversion sequence for reference 2284/// initialization. 2285static ImplicitConversionSequence 2286TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType, 2287 SourceLocation DeclLoc, 2288 bool SuppressUserConversions, 2289 bool AllowExplicit) { 2290 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 2291 2292 // Most paths end in a failed conversion. 2293 ImplicitConversionSequence ICS; 2294 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); 2295 2296 QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType(); 2297 QualType T2 = Init->getType(); 2298 2299 // If the initializer is the address of an overloaded function, try 2300 // to resolve the overloaded function. If all goes well, T2 is the 2301 // type of the resulting function. 2302 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { 2303 DeclAccessPair Found; 2304 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, 2305 false, Found)) 2306 T2 = Fn->getType(); 2307 } 2308 2309 // Compute some basic properties of the types and the initializer. 2310 bool isRValRef = DeclType->isRValueReferenceType(); 2311 bool DerivedToBase = false; 2312 Expr::isLvalueResult InitLvalue = Init->isLvalue(S.Context); 2313 Sema::ReferenceCompareResult RefRelationship 2314 = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase); 2315 2316 2317 // C++ [over.ics.ref]p3: 2318 // Except for an implicit object parameter, for which see 13.3.1, 2319 // a standard conversion sequence cannot be formed if it requires 2320 // binding an lvalue reference to non-const to an rvalue or 2321 // binding an rvalue reference to an lvalue. 2322 // 2323 // FIXME: DPG doesn't trust this code. It seems far too early to 2324 // abort because of a binding of an rvalue reference to an lvalue. 2325 if (isRValRef && InitLvalue == Expr::LV_Valid) 2326 return ICS; 2327 2328 // C++0x [dcl.init.ref]p16: 2329 // A reference to type "cv1 T1" is initialized by an expression 2330 // of type "cv2 T2" as follows: 2331 2332 // -- If the initializer expression 2333 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is 2334 // reference-compatible with "cv2 T2," or 2335 // 2336 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. 2337 if (InitLvalue == Expr::LV_Valid && 2338 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2339 // C++ [over.ics.ref]p1: 2340 // When a parameter of reference type binds directly (8.5.3) 2341 // to an argument expression, the implicit conversion sequence 2342 // is the identity conversion, unless the argument expression 2343 // has a type that is a derived class of the parameter type, 2344 // in which case the implicit conversion sequence is a 2345 // derived-to-base Conversion (13.3.3.1). 2346 ICS.setStandard(); 2347 ICS.Standard.First = ICK_Identity; 2348 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2349 ICS.Standard.Third = ICK_Identity; 2350 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2351 ICS.Standard.setToType(0, T2); 2352 ICS.Standard.setToType(1, T1); 2353 ICS.Standard.setToType(2, T1); 2354 ICS.Standard.ReferenceBinding = true; 2355 ICS.Standard.DirectBinding = true; 2356 ICS.Standard.RRefBinding = false; 2357 ICS.Standard.CopyConstructor = 0; 2358 2359 // Nothing more to do: the inaccessibility/ambiguity check for 2360 // derived-to-base conversions is suppressed when we're 2361 // computing the implicit conversion sequence (C++ 2362 // [over.best.ics]p2). 2363 return ICS; 2364 } 2365 2366 // -- has a class type (i.e., T2 is a class type), where T1 is 2367 // not reference-related to T2, and can be implicitly 2368 // converted to an lvalue of type "cv3 T3," where "cv1 T1" 2369 // is reference-compatible with "cv3 T3" 92) (this 2370 // conversion is selected by enumerating the applicable 2371 // conversion functions (13.3.1.6) and choosing the best 2372 // one through overload resolution (13.3)), 2373 if (!isRValRef && !SuppressUserConversions && T2->isRecordType() && 2374 !S.RequireCompleteType(DeclLoc, T2, 0) && 2375 RefRelationship == Sema::Ref_Incompatible) { 2376 CXXRecordDecl *T2RecordDecl 2377 = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl()); 2378 2379 OverloadCandidateSet CandidateSet(DeclLoc); 2380 const UnresolvedSetImpl *Conversions 2381 = T2RecordDecl->getVisibleConversionFunctions(); 2382 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 2383 E = Conversions->end(); I != E; ++I) { 2384 NamedDecl *D = *I; 2385 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext()); 2386 if (isa<UsingShadowDecl>(D)) 2387 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 2388 2389 FunctionTemplateDecl *ConvTemplate 2390 = dyn_cast<FunctionTemplateDecl>(D); 2391 CXXConversionDecl *Conv; 2392 if (ConvTemplate) 2393 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 2394 else 2395 Conv = cast<CXXConversionDecl>(D); 2396 2397 // If the conversion function doesn't return a reference type, 2398 // it can't be considered for this conversion. 2399 if (Conv->getConversionType()->isLValueReferenceType() && 2400 (AllowExplicit || !Conv->isExplicit())) { 2401 if (ConvTemplate) 2402 S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC, 2403 Init, DeclType, CandidateSet); 2404 else 2405 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init, 2406 DeclType, CandidateSet); 2407 } 2408 } 2409 2410 OverloadCandidateSet::iterator Best; 2411 switch (S.BestViableFunction(CandidateSet, DeclLoc, Best)) { 2412 case OR_Success: 2413 // C++ [over.ics.ref]p1: 2414 // 2415 // [...] If the parameter binds directly to the result of 2416 // applying a conversion function to the argument 2417 // expression, the implicit conversion sequence is a 2418 // user-defined conversion sequence (13.3.3.1.2), with the 2419 // second standard conversion sequence either an identity 2420 // conversion or, if the conversion function returns an 2421 // entity of a type that is a derived class of the parameter 2422 // type, a derived-to-base Conversion. 2423 if (!Best->FinalConversion.DirectBinding) 2424 break; 2425 2426 ICS.setUserDefined(); 2427 ICS.UserDefined.Before = Best->Conversions[0].Standard; 2428 ICS.UserDefined.After = Best->FinalConversion; 2429 ICS.UserDefined.ConversionFunction = Best->Function; 2430 ICS.UserDefined.EllipsisConversion = false; 2431 assert(ICS.UserDefined.After.ReferenceBinding && 2432 ICS.UserDefined.After.DirectBinding && 2433 "Expected a direct reference binding!"); 2434 return ICS; 2435 2436 case OR_Ambiguous: 2437 ICS.setAmbiguous(); 2438 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 2439 Cand != CandidateSet.end(); ++Cand) 2440 if (Cand->Viable) 2441 ICS.Ambiguous.addConversion(Cand->Function); 2442 return ICS; 2443 2444 case OR_No_Viable_Function: 2445 case OR_Deleted: 2446 // There was no suitable conversion, or we found a deleted 2447 // conversion; continue with other checks. 2448 break; 2449 } 2450 } 2451 2452 // -- Otherwise, the reference shall be to a non-volatile const 2453 // type (i.e., cv1 shall be const), or the reference shall be an 2454 // rvalue reference and the initializer expression shall be an rvalue. 2455 // 2456 // We actually handle one oddity of C++ [over.ics.ref] at this 2457 // point, which is that, due to p2 (which short-circuits reference 2458 // binding by only attempting a simple conversion for non-direct 2459 // bindings) and p3's strange wording, we allow a const volatile 2460 // reference to bind to an rvalue. Hence the check for the presence 2461 // of "const" rather than checking for "const" being the only 2462 // qualifier. 2463 if (!isRValRef && !T1.isConstQualified()) 2464 return ICS; 2465 2466 // -- if T2 is a class type and 2467 // -- the initializer expression is an rvalue and "cv1 T1" 2468 // is reference-compatible with "cv2 T2," or 2469 // 2470 // -- T1 is not reference-related to T2 and the initializer 2471 // expression can be implicitly converted to an rvalue 2472 // of type "cv3 T3" (this conversion is selected by 2473 // enumerating the applicable conversion functions 2474 // (13.3.1.6) and choosing the best one through overload 2475 // resolution (13.3)), 2476 // 2477 // then the reference is bound to the initializer 2478 // expression rvalue in the first case and to the object 2479 // that is the result of the conversion in the second case 2480 // (or, in either case, to the appropriate base class 2481 // subobject of the object). 2482 // 2483 // We're only checking the first case here, which is a direct 2484 // binding in C++0x but not in C++03. 2485 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 2486 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2487 ICS.setStandard(); 2488 ICS.Standard.First = ICK_Identity; 2489 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2490 ICS.Standard.Third = ICK_Identity; 2491 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2492 ICS.Standard.setToType(0, T2); 2493 ICS.Standard.setToType(1, T1); 2494 ICS.Standard.setToType(2, T1); 2495 ICS.Standard.ReferenceBinding = true; 2496 ICS.Standard.DirectBinding = S.getLangOptions().CPlusPlus0x; 2497 ICS.Standard.RRefBinding = isRValRef; 2498 ICS.Standard.CopyConstructor = 0; 2499 return ICS; 2500 } 2501 2502 // -- Otherwise, a temporary of type "cv1 T1" is created and 2503 // initialized from the initializer expression using the 2504 // rules for a non-reference copy initialization (8.5). The 2505 // reference is then bound to the temporary. If T1 is 2506 // reference-related to T2, cv1 must be the same 2507 // cv-qualification as, or greater cv-qualification than, 2508 // cv2; otherwise, the program is ill-formed. 2509 if (RefRelationship == Sema::Ref_Related) { 2510 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 2511 // we would be reference-compatible or reference-compatible with 2512 // added qualification. But that wasn't the case, so the reference 2513 // initialization fails. 2514 return ICS; 2515 } 2516 2517 // If at least one of the types is a class type, the types are not 2518 // related, and we aren't allowed any user conversions, the 2519 // reference binding fails. This case is important for breaking 2520 // recursion, since TryImplicitConversion below will attempt to 2521 // create a temporary through the use of a copy constructor. 2522 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && 2523 (T1->isRecordType() || T2->isRecordType())) 2524 return ICS; 2525 2526 // C++ [over.ics.ref]p2: 2527 // When a parameter of reference type is not bound directly to 2528 // an argument expression, the conversion sequence is the one 2529 // required to convert the argument expression to the 2530 // underlying type of the reference according to 2531 // 13.3.3.1. Conceptually, this conversion sequence corresponds 2532 // to copy-initializing a temporary of the underlying type with 2533 // the argument expression. Any difference in top-level 2534 // cv-qualification is subsumed by the initialization itself 2535 // and does not constitute a conversion. 2536 ICS = S.TryImplicitConversion(Init, T1, SuppressUserConversions, 2537 /*AllowExplicit=*/false, 2538 /*InOverloadResolution=*/false); 2539 2540 // Of course, that's still a reference binding. 2541 if (ICS.isStandard()) { 2542 ICS.Standard.ReferenceBinding = true; 2543 ICS.Standard.RRefBinding = isRValRef; 2544 } else if (ICS.isUserDefined()) { 2545 ICS.UserDefined.After.ReferenceBinding = true; 2546 ICS.UserDefined.After.RRefBinding = isRValRef; 2547 } 2548 return ICS; 2549} 2550 2551/// TryCopyInitialization - Try to copy-initialize a value of type 2552/// ToType from the expression From. Return the implicit conversion 2553/// sequence required to pass this argument, which may be a bad 2554/// conversion sequence (meaning that the argument cannot be passed to 2555/// a parameter of this type). If @p SuppressUserConversions, then we 2556/// do not permit any user-defined conversion sequences. 2557static ImplicitConversionSequence 2558TryCopyInitialization(Sema &S, Expr *From, QualType ToType, 2559 bool SuppressUserConversions, 2560 bool InOverloadResolution) { 2561 if (ToType->isReferenceType()) 2562 return TryReferenceInit(S, From, ToType, 2563 /*FIXME:*/From->getLocStart(), 2564 SuppressUserConversions, 2565 /*AllowExplicit=*/false); 2566 2567 return S.TryImplicitConversion(From, ToType, 2568 SuppressUserConversions, 2569 /*AllowExplicit=*/false, 2570 InOverloadResolution); 2571} 2572 2573/// TryObjectArgumentInitialization - Try to initialize the object 2574/// parameter of the given member function (@c Method) from the 2575/// expression @p From. 2576ImplicitConversionSequence 2577Sema::TryObjectArgumentInitialization(QualType OrigFromType, 2578 CXXMethodDecl *Method, 2579 CXXRecordDecl *ActingContext) { 2580 QualType ClassType = Context.getTypeDeclType(ActingContext); 2581 // [class.dtor]p2: A destructor can be invoked for a const, volatile or 2582 // const volatile object. 2583 unsigned Quals = isa<CXXDestructorDecl>(Method) ? 2584 Qualifiers::Const | Qualifiers::Volatile : Method->getTypeQualifiers(); 2585 QualType ImplicitParamType = Context.getCVRQualifiedType(ClassType, Quals); 2586 2587 // Set up the conversion sequence as a "bad" conversion, to allow us 2588 // to exit early. 2589 ImplicitConversionSequence ICS; 2590 2591 // We need to have an object of class type. 2592 QualType FromType = OrigFromType; 2593 if (const PointerType *PT = FromType->getAs<PointerType>()) 2594 FromType = PT->getPointeeType(); 2595 2596 assert(FromType->isRecordType()); 2597 2598 // The implicit object parameter is has the type "reference to cv X", 2599 // where X is the class of which the function is a member 2600 // (C++ [over.match.funcs]p4). However, when finding an implicit 2601 // conversion sequence for the argument, we are not allowed to 2602 // create temporaries or perform user-defined conversions 2603 // (C++ [over.match.funcs]p5). We perform a simplified version of 2604 // reference binding here, that allows class rvalues to bind to 2605 // non-constant references. 2606 2607 // First check the qualifiers. We don't care about lvalue-vs-rvalue 2608 // with the implicit object parameter (C++ [over.match.funcs]p5). 2609 QualType FromTypeCanon = Context.getCanonicalType(FromType); 2610 if (ImplicitParamType.getCVRQualifiers() 2611 != FromTypeCanon.getLocalCVRQualifiers() && 2612 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { 2613 ICS.setBad(BadConversionSequence::bad_qualifiers, 2614 OrigFromType, ImplicitParamType); 2615 return ICS; 2616 } 2617 2618 // Check that we have either the same type or a derived type. It 2619 // affects the conversion rank. 2620 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 2621 ImplicitConversionKind SecondKind; 2622 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { 2623 SecondKind = ICK_Identity; 2624 } else if (IsDerivedFrom(FromType, ClassType)) 2625 SecondKind = ICK_Derived_To_Base; 2626 else { 2627 ICS.setBad(BadConversionSequence::unrelated_class, 2628 FromType, ImplicitParamType); 2629 return ICS; 2630 } 2631 2632 // Success. Mark this as a reference binding. 2633 ICS.setStandard(); 2634 ICS.Standard.setAsIdentityConversion(); 2635 ICS.Standard.Second = SecondKind; 2636 ICS.Standard.setFromType(FromType); 2637 ICS.Standard.setAllToTypes(ImplicitParamType); 2638 ICS.Standard.ReferenceBinding = true; 2639 ICS.Standard.DirectBinding = true; 2640 ICS.Standard.RRefBinding = false; 2641 return ICS; 2642} 2643 2644/// PerformObjectArgumentInitialization - Perform initialization of 2645/// the implicit object parameter for the given Method with the given 2646/// expression. 2647bool 2648Sema::PerformObjectArgumentInitialization(Expr *&From, 2649 NestedNameSpecifier *Qualifier, 2650 NamedDecl *FoundDecl, 2651 CXXMethodDecl *Method) { 2652 QualType FromRecordType, DestType; 2653 QualType ImplicitParamRecordType = 2654 Method->getThisType(Context)->getAs<PointerType>()->getPointeeType(); 2655 2656 if (const PointerType *PT = From->getType()->getAs<PointerType>()) { 2657 FromRecordType = PT->getPointeeType(); 2658 DestType = Method->getThisType(Context); 2659 } else { 2660 FromRecordType = From->getType(); 2661 DestType = ImplicitParamRecordType; 2662 } 2663 2664 // Note that we always use the true parent context when performing 2665 // the actual argument initialization. 2666 ImplicitConversionSequence ICS 2667 = TryObjectArgumentInitialization(From->getType(), Method, 2668 Method->getParent()); 2669 if (ICS.isBad()) 2670 return Diag(From->getSourceRange().getBegin(), 2671 diag::err_implicit_object_parameter_init) 2672 << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); 2673 2674 if (ICS.Standard.Second == ICK_Derived_To_Base) 2675 return PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); 2676 2677 if (!Context.hasSameType(From->getType(), DestType)) 2678 ImpCastExprToType(From, DestType, CastExpr::CK_NoOp, 2679 /*isLvalue=*/!From->getType()->isPointerType()); 2680 return false; 2681} 2682 2683/// TryContextuallyConvertToBool - Attempt to contextually convert the 2684/// expression From to bool (C++0x [conv]p3). 2685ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 2686 return TryImplicitConversion(From, Context.BoolTy, 2687 // FIXME: Are these flags correct? 2688 /*SuppressUserConversions=*/false, 2689 /*AllowExplicit=*/true, 2690 /*InOverloadResolution=*/false); 2691} 2692 2693/// PerformContextuallyConvertToBool - Perform a contextual conversion 2694/// of the expression From to bool (C++0x [conv]p3). 2695bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2696 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2697 if (!ICS.isBad()) 2698 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); 2699 2700 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2701 return Diag(From->getSourceRange().getBegin(), 2702 diag::err_typecheck_bool_condition) 2703 << From->getType() << From->getSourceRange(); 2704 return true; 2705} 2706 2707/// AddOverloadCandidate - Adds the given function to the set of 2708/// candidate functions, using the given function call arguments. If 2709/// @p SuppressUserConversions, then don't allow user-defined 2710/// conversions via constructors or conversion operators. 2711/// 2712/// \para PartialOverloading true if we are performing "partial" overloading 2713/// based on an incomplete set of function arguments. This feature is used by 2714/// code completion. 2715void 2716Sema::AddOverloadCandidate(FunctionDecl *Function, 2717 DeclAccessPair FoundDecl, 2718 Expr **Args, unsigned NumArgs, 2719 OverloadCandidateSet& CandidateSet, 2720 bool SuppressUserConversions, 2721 bool PartialOverloading) { 2722 const FunctionProtoType* Proto 2723 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2724 assert(Proto && "Functions without a prototype cannot be overloaded"); 2725 assert(!Function->getDescribedFunctionTemplate() && 2726 "Use AddTemplateOverloadCandidate for function templates"); 2727 2728 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2729 if (!isa<CXXConstructorDecl>(Method)) { 2730 // If we get here, it's because we're calling a member function 2731 // that is named without a member access expression (e.g., 2732 // "this->f") that was either written explicitly or created 2733 // implicitly. This can happen with a qualified call to a member 2734 // function, e.g., X::f(). We use an empty type for the implied 2735 // object argument (C++ [over.call.func]p3), and the acting context 2736 // is irrelevant. 2737 AddMethodCandidate(Method, FoundDecl, Method->getParent(), 2738 QualType(), Args, NumArgs, CandidateSet, 2739 SuppressUserConversions); 2740 return; 2741 } 2742 // We treat a constructor like a non-member function, since its object 2743 // argument doesn't participate in overload resolution. 2744 } 2745 2746 if (!CandidateSet.isNewCandidate(Function)) 2747 return; 2748 2749 // Overload resolution is always an unevaluated context. 2750 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2751 2752 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2753 // C++ [class.copy]p3: 2754 // A member function template is never instantiated to perform the copy 2755 // of a class object to an object of its class type. 2756 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2757 if (NumArgs == 1 && 2758 Constructor->isCopyConstructorLikeSpecialization() && 2759 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || 2760 IsDerivedFrom(Args[0]->getType(), ClassType))) 2761 return; 2762 } 2763 2764 // Add this candidate 2765 CandidateSet.push_back(OverloadCandidate()); 2766 OverloadCandidate& Candidate = CandidateSet.back(); 2767 Candidate.FoundDecl = FoundDecl; 2768 Candidate.Function = Function; 2769 Candidate.Viable = true; 2770 Candidate.IsSurrogate = false; 2771 Candidate.IgnoreObjectArgument = false; 2772 2773 unsigned NumArgsInProto = Proto->getNumArgs(); 2774 2775 // (C++ 13.3.2p2): A candidate function having fewer than m 2776 // parameters is viable only if it has an ellipsis in its parameter 2777 // list (8.3.5). 2778 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 2779 !Proto->isVariadic()) { 2780 Candidate.Viable = false; 2781 Candidate.FailureKind = ovl_fail_too_many_arguments; 2782 return; 2783 } 2784 2785 // (C++ 13.3.2p2): A candidate function having more than m parameters 2786 // is viable only if the (m+1)st parameter has a default argument 2787 // (8.3.6). For the purposes of overload resolution, the 2788 // parameter list is truncated on the right, so that there are 2789 // exactly m parameters. 2790 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2791 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 2792 // Not enough arguments. 2793 Candidate.Viable = false; 2794 Candidate.FailureKind = ovl_fail_too_few_arguments; 2795 return; 2796 } 2797 2798 // Determine the implicit conversion sequences for each of the 2799 // arguments. 2800 Candidate.Conversions.resize(NumArgs); 2801 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2802 if (ArgIdx < NumArgsInProto) { 2803 // (C++ 13.3.2p3): for F to be a viable function, there shall 2804 // exist for each argument an implicit conversion sequence 2805 // (13.3.3.1) that converts that argument to the corresponding 2806 // parameter of F. 2807 QualType ParamType = Proto->getArgType(ArgIdx); 2808 Candidate.Conversions[ArgIdx] 2809 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 2810 SuppressUserConversions, 2811 /*InOverloadResolution=*/true); 2812 if (Candidate.Conversions[ArgIdx].isBad()) { 2813 Candidate.Viable = false; 2814 Candidate.FailureKind = ovl_fail_bad_conversion; 2815 break; 2816 } 2817 } else { 2818 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2819 // argument for which there is no corresponding parameter is 2820 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2821 Candidate.Conversions[ArgIdx].setEllipsis(); 2822 } 2823 } 2824} 2825 2826/// \brief Add all of the function declarations in the given function set to 2827/// the overload canddiate set. 2828void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, 2829 Expr **Args, unsigned NumArgs, 2830 OverloadCandidateSet& CandidateSet, 2831 bool SuppressUserConversions) { 2832 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { 2833 NamedDecl *D = F.getDecl()->getUnderlyingDecl(); 2834 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 2835 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 2836 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), 2837 cast<CXXMethodDecl>(FD)->getParent(), 2838 Args[0]->getType(), Args + 1, NumArgs - 1, 2839 CandidateSet, SuppressUserConversions); 2840 else 2841 AddOverloadCandidate(FD, F.getPair(), Args, NumArgs, CandidateSet, 2842 SuppressUserConversions); 2843 } else { 2844 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D); 2845 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 2846 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 2847 AddMethodTemplateCandidate(FunTmpl, F.getPair(), 2848 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 2849 /*FIXME: explicit args */ 0, 2850 Args[0]->getType(), Args + 1, NumArgs - 1, 2851 CandidateSet, 2852 SuppressUserConversions); 2853 else 2854 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), 2855 /*FIXME: explicit args */ 0, 2856 Args, NumArgs, CandidateSet, 2857 SuppressUserConversions); 2858 } 2859 } 2860} 2861 2862/// AddMethodCandidate - Adds a named decl (which is some kind of 2863/// method) as a method candidate to the given overload set. 2864void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, 2865 QualType ObjectType, 2866 Expr **Args, unsigned NumArgs, 2867 OverloadCandidateSet& CandidateSet, 2868 bool SuppressUserConversions) { 2869 NamedDecl *Decl = FoundDecl.getDecl(); 2870 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 2871 2872 if (isa<UsingShadowDecl>(Decl)) 2873 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 2874 2875 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 2876 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 2877 "Expected a member function template"); 2878 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, 2879 /*ExplicitArgs*/ 0, 2880 ObjectType, Args, NumArgs, 2881 CandidateSet, 2882 SuppressUserConversions); 2883 } else { 2884 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, 2885 ObjectType, Args, NumArgs, 2886 CandidateSet, SuppressUserConversions); 2887 } 2888} 2889 2890/// AddMethodCandidate - Adds the given C++ member function to the set 2891/// of candidate functions, using the given function call arguments 2892/// and the object argument (@c Object). For example, in a call 2893/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2894/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2895/// allow user-defined conversions via constructors or conversion 2896/// operators. 2897void 2898Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, 2899 CXXRecordDecl *ActingContext, QualType ObjectType, 2900 Expr **Args, unsigned NumArgs, 2901 OverloadCandidateSet& CandidateSet, 2902 bool SuppressUserConversions) { 2903 const FunctionProtoType* Proto 2904 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 2905 assert(Proto && "Methods without a prototype cannot be overloaded"); 2906 assert(!isa<CXXConstructorDecl>(Method) && 2907 "Use AddOverloadCandidate for constructors"); 2908 2909 if (!CandidateSet.isNewCandidate(Method)) 2910 return; 2911 2912 // Overload resolution is always an unevaluated context. 2913 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2914 2915 // Add this candidate 2916 CandidateSet.push_back(OverloadCandidate()); 2917 OverloadCandidate& Candidate = CandidateSet.back(); 2918 Candidate.FoundDecl = FoundDecl; 2919 Candidate.Function = Method; 2920 Candidate.IsSurrogate = false; 2921 Candidate.IgnoreObjectArgument = false; 2922 2923 unsigned NumArgsInProto = Proto->getNumArgs(); 2924 2925 // (C++ 13.3.2p2): A candidate function having fewer than m 2926 // parameters is viable only if it has an ellipsis in its parameter 2927 // list (8.3.5). 2928 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2929 Candidate.Viable = false; 2930 Candidate.FailureKind = ovl_fail_too_many_arguments; 2931 return; 2932 } 2933 2934 // (C++ 13.3.2p2): A candidate function having more than m parameters 2935 // is viable only if the (m+1)st parameter has a default argument 2936 // (8.3.6). For the purposes of overload resolution, the 2937 // parameter list is truncated on the right, so that there are 2938 // exactly m parameters. 2939 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2940 if (NumArgs < MinRequiredArgs) { 2941 // Not enough arguments. 2942 Candidate.Viable = false; 2943 Candidate.FailureKind = ovl_fail_too_few_arguments; 2944 return; 2945 } 2946 2947 Candidate.Viable = true; 2948 Candidate.Conversions.resize(NumArgs + 1); 2949 2950 if (Method->isStatic() || ObjectType.isNull()) 2951 // The implicit object argument is ignored. 2952 Candidate.IgnoreObjectArgument = true; 2953 else { 2954 // Determine the implicit conversion sequence for the object 2955 // parameter. 2956 Candidate.Conversions[0] 2957 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 2958 if (Candidate.Conversions[0].isBad()) { 2959 Candidate.Viable = false; 2960 Candidate.FailureKind = ovl_fail_bad_conversion; 2961 return; 2962 } 2963 } 2964 2965 // Determine the implicit conversion sequences for each of the 2966 // arguments. 2967 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2968 if (ArgIdx < NumArgsInProto) { 2969 // (C++ 13.3.2p3): for F to be a viable function, there shall 2970 // exist for each argument an implicit conversion sequence 2971 // (13.3.3.1) that converts that argument to the corresponding 2972 // parameter of F. 2973 QualType ParamType = Proto->getArgType(ArgIdx); 2974 Candidate.Conversions[ArgIdx + 1] 2975 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 2976 SuppressUserConversions, 2977 /*InOverloadResolution=*/true); 2978 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 2979 Candidate.Viable = false; 2980 Candidate.FailureKind = ovl_fail_bad_conversion; 2981 break; 2982 } 2983 } else { 2984 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2985 // argument for which there is no corresponding parameter is 2986 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2987 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 2988 } 2989 } 2990} 2991 2992/// \brief Add a C++ member function template as a candidate to the candidate 2993/// set, using template argument deduction to produce an appropriate member 2994/// function template specialization. 2995void 2996Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 2997 DeclAccessPair FoundDecl, 2998 CXXRecordDecl *ActingContext, 2999 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3000 QualType ObjectType, 3001 Expr **Args, unsigned NumArgs, 3002 OverloadCandidateSet& CandidateSet, 3003 bool SuppressUserConversions) { 3004 if (!CandidateSet.isNewCandidate(MethodTmpl)) 3005 return; 3006 3007 // C++ [over.match.funcs]p7: 3008 // In each case where a candidate is a function template, candidate 3009 // function template specializations are generated using template argument 3010 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3011 // candidate functions in the usual way.113) A given name can refer to one 3012 // or more function templates and also to a set of overloaded non-template 3013 // functions. In such a case, the candidate functions generated from each 3014 // function template are combined with the set of non-template candidate 3015 // functions. 3016 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3017 FunctionDecl *Specialization = 0; 3018 if (TemplateDeductionResult Result 3019 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 3020 Args, NumArgs, Specialization, Info)) { 3021 // FIXME: Record what happened with template argument deduction, so 3022 // that we can give the user a beautiful diagnostic. 3023 (void)Result; 3024 return; 3025 } 3026 3027 // Add the function template specialization produced by template argument 3028 // deduction as a candidate. 3029 assert(Specialization && "Missing member function template specialization?"); 3030 assert(isa<CXXMethodDecl>(Specialization) && 3031 "Specialization is not a member function?"); 3032 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl, 3033 ActingContext, ObjectType, Args, NumArgs, 3034 CandidateSet, SuppressUserConversions); 3035} 3036 3037/// \brief Add a C++ function template specialization as a candidate 3038/// in the candidate set, using template argument deduction to produce 3039/// an appropriate function template specialization. 3040void 3041Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 3042 DeclAccessPair FoundDecl, 3043 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3044 Expr **Args, unsigned NumArgs, 3045 OverloadCandidateSet& CandidateSet, 3046 bool SuppressUserConversions) { 3047 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3048 return; 3049 3050 // C++ [over.match.funcs]p7: 3051 // In each case where a candidate is a function template, candidate 3052 // function template specializations are generated using template argument 3053 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3054 // candidate functions in the usual way.113) A given name can refer to one 3055 // or more function templates and also to a set of overloaded non-template 3056 // functions. In such a case, the candidate functions generated from each 3057 // function template are combined with the set of non-template candidate 3058 // functions. 3059 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3060 FunctionDecl *Specialization = 0; 3061 if (TemplateDeductionResult Result 3062 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3063 Args, NumArgs, Specialization, Info)) { 3064 CandidateSet.push_back(OverloadCandidate()); 3065 OverloadCandidate &Candidate = CandidateSet.back(); 3066 Candidate.FoundDecl = FoundDecl; 3067 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3068 Candidate.Viable = false; 3069 Candidate.FailureKind = ovl_fail_bad_deduction; 3070 Candidate.IsSurrogate = false; 3071 Candidate.IgnoreObjectArgument = false; 3072 3073 // TODO: record more information about failed template arguments 3074 Candidate.DeductionFailure.Result = Result; 3075 Candidate.DeductionFailure.TemplateParameter = Info.Param.getOpaqueValue(); 3076 return; 3077 } 3078 3079 // Add the function template specialization produced by template argument 3080 // deduction as a candidate. 3081 assert(Specialization && "Missing function template specialization?"); 3082 AddOverloadCandidate(Specialization, FoundDecl, Args, NumArgs, CandidateSet, 3083 SuppressUserConversions); 3084} 3085 3086/// AddConversionCandidate - Add a C++ conversion function as a 3087/// candidate in the candidate set (C++ [over.match.conv], 3088/// C++ [over.match.copy]). From is the expression we're converting from, 3089/// and ToType is the type that we're eventually trying to convert to 3090/// (which may or may not be the same type as the type that the 3091/// conversion function produces). 3092void 3093Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 3094 DeclAccessPair FoundDecl, 3095 CXXRecordDecl *ActingContext, 3096 Expr *From, QualType ToType, 3097 OverloadCandidateSet& CandidateSet) { 3098 assert(!Conversion->getDescribedFunctionTemplate() && 3099 "Conversion function templates use AddTemplateConversionCandidate"); 3100 QualType ConvType = Conversion->getConversionType().getNonReferenceType(); 3101 if (!CandidateSet.isNewCandidate(Conversion)) 3102 return; 3103 3104 // Overload resolution is always an unevaluated context. 3105 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3106 3107 // Add this candidate 3108 CandidateSet.push_back(OverloadCandidate()); 3109 OverloadCandidate& Candidate = CandidateSet.back(); 3110 Candidate.FoundDecl = FoundDecl; 3111 Candidate.Function = Conversion; 3112 Candidate.IsSurrogate = false; 3113 Candidate.IgnoreObjectArgument = false; 3114 Candidate.FinalConversion.setAsIdentityConversion(); 3115 Candidate.FinalConversion.setFromType(ConvType); 3116 Candidate.FinalConversion.setAllToTypes(ToType); 3117 3118 // Determine the implicit conversion sequence for the implicit 3119 // object parameter. 3120 Candidate.Viable = true; 3121 Candidate.Conversions.resize(1); 3122 Candidate.Conversions[0] 3123 = TryObjectArgumentInitialization(From->getType(), Conversion, 3124 ActingContext); 3125 // Conversion functions to a different type in the base class is visible in 3126 // the derived class. So, a derived to base conversion should not participate 3127 // in overload resolution. 3128 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 3129 Candidate.Conversions[0].Standard.Second = ICK_Identity; 3130 if (Candidate.Conversions[0].isBad()) { 3131 Candidate.Viable = false; 3132 Candidate.FailureKind = ovl_fail_bad_conversion; 3133 return; 3134 } 3135 3136 // We won't go through a user-define type conversion function to convert a 3137 // derived to base as such conversions are given Conversion Rank. They only 3138 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 3139 QualType FromCanon 3140 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 3141 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 3142 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 3143 Candidate.Viable = false; 3144 Candidate.FailureKind = ovl_fail_trivial_conversion; 3145 return; 3146 } 3147 3148 // To determine what the conversion from the result of calling the 3149 // conversion function to the type we're eventually trying to 3150 // convert to (ToType), we need to synthesize a call to the 3151 // conversion function and attempt copy initialization from it. This 3152 // makes sure that we get the right semantics with respect to 3153 // lvalues/rvalues and the type. Fortunately, we can allocate this 3154 // call on the stack and we don't need its arguments to be 3155 // well-formed. 3156 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 3157 From->getLocStart()); 3158 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 3159 CastExpr::CK_FunctionToPointerDecay, 3160 &ConversionRef, CXXBaseSpecifierArray(), false); 3161 3162 // Note that it is safe to allocate CallExpr on the stack here because 3163 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 3164 // allocator). 3165 CallExpr Call(Context, &ConversionFn, 0, 0, 3166 Conversion->getConversionType().getNonReferenceType(), 3167 From->getLocStart()); 3168 ImplicitConversionSequence ICS = 3169 TryCopyInitialization(*this, &Call, ToType, 3170 /*SuppressUserConversions=*/true, 3171 /*InOverloadResolution=*/false); 3172 3173 switch (ICS.getKind()) { 3174 case ImplicitConversionSequence::StandardConversion: 3175 Candidate.FinalConversion = ICS.Standard; 3176 3177 // C++ [over.ics.user]p3: 3178 // If the user-defined conversion is specified by a specialization of a 3179 // conversion function template, the second standard conversion sequence 3180 // shall have exact match rank. 3181 if (Conversion->getPrimaryTemplate() && 3182 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { 3183 Candidate.Viable = false; 3184 Candidate.FailureKind = ovl_fail_final_conversion_not_exact; 3185 } 3186 3187 break; 3188 3189 case ImplicitConversionSequence::BadConversion: 3190 Candidate.Viable = false; 3191 Candidate.FailureKind = ovl_fail_bad_final_conversion; 3192 break; 3193 3194 default: 3195 assert(false && 3196 "Can only end up with a standard conversion sequence or failure"); 3197 } 3198} 3199 3200/// \brief Adds a conversion function template specialization 3201/// candidate to the overload set, using template argument deduction 3202/// to deduce the template arguments of the conversion function 3203/// template from the type that we are converting to (C++ 3204/// [temp.deduct.conv]). 3205void 3206Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 3207 DeclAccessPair FoundDecl, 3208 CXXRecordDecl *ActingDC, 3209 Expr *From, QualType ToType, 3210 OverloadCandidateSet &CandidateSet) { 3211 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 3212 "Only conversion function templates permitted here"); 3213 3214 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3215 return; 3216 3217 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3218 CXXConversionDecl *Specialization = 0; 3219 if (TemplateDeductionResult Result 3220 = DeduceTemplateArguments(FunctionTemplate, ToType, 3221 Specialization, Info)) { 3222 // FIXME: Record what happened with template argument deduction, so 3223 // that we can give the user a beautiful diagnostic. 3224 (void)Result; 3225 return; 3226 } 3227 3228 // Add the conversion function template specialization produced by 3229 // template argument deduction as a candidate. 3230 assert(Specialization && "Missing function template specialization?"); 3231 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, 3232 CandidateSet); 3233} 3234 3235/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 3236/// converts the given @c Object to a function pointer via the 3237/// conversion function @c Conversion, and then attempts to call it 3238/// with the given arguments (C++ [over.call.object]p2-4). Proto is 3239/// the type of function that we'll eventually be calling. 3240void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 3241 DeclAccessPair FoundDecl, 3242 CXXRecordDecl *ActingContext, 3243 const FunctionProtoType *Proto, 3244 QualType ObjectType, 3245 Expr **Args, unsigned NumArgs, 3246 OverloadCandidateSet& CandidateSet) { 3247 if (!CandidateSet.isNewCandidate(Conversion)) 3248 return; 3249 3250 // Overload resolution is always an unevaluated context. 3251 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3252 3253 CandidateSet.push_back(OverloadCandidate()); 3254 OverloadCandidate& Candidate = CandidateSet.back(); 3255 Candidate.FoundDecl = FoundDecl; 3256 Candidate.Function = 0; 3257 Candidate.Surrogate = Conversion; 3258 Candidate.Viable = true; 3259 Candidate.IsSurrogate = true; 3260 Candidate.IgnoreObjectArgument = false; 3261 Candidate.Conversions.resize(NumArgs + 1); 3262 3263 // Determine the implicit conversion sequence for the implicit 3264 // object parameter. 3265 ImplicitConversionSequence ObjectInit 3266 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 3267 if (ObjectInit.isBad()) { 3268 Candidate.Viable = false; 3269 Candidate.FailureKind = ovl_fail_bad_conversion; 3270 Candidate.Conversions[0] = ObjectInit; 3271 return; 3272 } 3273 3274 // The first conversion is actually a user-defined conversion whose 3275 // first conversion is ObjectInit's standard conversion (which is 3276 // effectively a reference binding). Record it as such. 3277 Candidate.Conversions[0].setUserDefined(); 3278 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 3279 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 3280 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 3281 Candidate.Conversions[0].UserDefined.After 3282 = Candidate.Conversions[0].UserDefined.Before; 3283 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 3284 3285 // Find the 3286 unsigned NumArgsInProto = Proto->getNumArgs(); 3287 3288 // (C++ 13.3.2p2): A candidate function having fewer than m 3289 // parameters is viable only if it has an ellipsis in its parameter 3290 // list (8.3.5). 3291 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3292 Candidate.Viable = false; 3293 Candidate.FailureKind = ovl_fail_too_many_arguments; 3294 return; 3295 } 3296 3297 // Function types don't have any default arguments, so just check if 3298 // we have enough arguments. 3299 if (NumArgs < NumArgsInProto) { 3300 // Not enough arguments. 3301 Candidate.Viable = false; 3302 Candidate.FailureKind = ovl_fail_too_few_arguments; 3303 return; 3304 } 3305 3306 // Determine the implicit conversion sequences for each of the 3307 // arguments. 3308 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3309 if (ArgIdx < NumArgsInProto) { 3310 // (C++ 13.3.2p3): for F to be a viable function, there shall 3311 // exist for each argument an implicit conversion sequence 3312 // (13.3.3.1) that converts that argument to the corresponding 3313 // parameter of F. 3314 QualType ParamType = Proto->getArgType(ArgIdx); 3315 Candidate.Conversions[ArgIdx + 1] 3316 = TryCopyInitialization(*this, Args[ArgIdx], ParamType, 3317 /*SuppressUserConversions=*/false, 3318 /*InOverloadResolution=*/false); 3319 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3320 Candidate.Viable = false; 3321 Candidate.FailureKind = ovl_fail_bad_conversion; 3322 break; 3323 } 3324 } else { 3325 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3326 // argument for which there is no corresponding parameter is 3327 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3328 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3329 } 3330 } 3331} 3332 3333/// \brief Add overload candidates for overloaded operators that are 3334/// member functions. 3335/// 3336/// Add the overloaded operator candidates that are member functions 3337/// for the operator Op that was used in an operator expression such 3338/// as "x Op y". , Args/NumArgs provides the operator arguments, and 3339/// CandidateSet will store the added overload candidates. (C++ 3340/// [over.match.oper]). 3341void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 3342 SourceLocation OpLoc, 3343 Expr **Args, unsigned NumArgs, 3344 OverloadCandidateSet& CandidateSet, 3345 SourceRange OpRange) { 3346 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3347 3348 // C++ [over.match.oper]p3: 3349 // For a unary operator @ with an operand of a type whose 3350 // cv-unqualified version is T1, and for a binary operator @ with 3351 // a left operand of a type whose cv-unqualified version is T1 and 3352 // a right operand of a type whose cv-unqualified version is T2, 3353 // three sets of candidate functions, designated member 3354 // candidates, non-member candidates and built-in candidates, are 3355 // constructed as follows: 3356 QualType T1 = Args[0]->getType(); 3357 QualType T2; 3358 if (NumArgs > 1) 3359 T2 = Args[1]->getType(); 3360 3361 // -- If T1 is a class type, the set of member candidates is the 3362 // result of the qualified lookup of T1::operator@ 3363 // (13.3.1.1.1); otherwise, the set of member candidates is 3364 // empty. 3365 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 3366 // Complete the type if it can be completed. Otherwise, we're done. 3367 if (RequireCompleteType(OpLoc, T1, PDiag())) 3368 return; 3369 3370 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 3371 LookupQualifiedName(Operators, T1Rec->getDecl()); 3372 Operators.suppressDiagnostics(); 3373 3374 for (LookupResult::iterator Oper = Operators.begin(), 3375 OperEnd = Operators.end(); 3376 Oper != OperEnd; 3377 ++Oper) 3378 AddMethodCandidate(Oper.getPair(), Args[0]->getType(), 3379 Args + 1, NumArgs - 1, CandidateSet, 3380 /* SuppressUserConversions = */ false); 3381 } 3382} 3383 3384/// AddBuiltinCandidate - Add a candidate for a built-in 3385/// operator. ResultTy and ParamTys are the result and parameter types 3386/// of the built-in candidate, respectively. Args and NumArgs are the 3387/// arguments being passed to the candidate. IsAssignmentOperator 3388/// should be true when this built-in candidate is an assignment 3389/// operator. NumContextualBoolArguments is the number of arguments 3390/// (at the beginning of the argument list) that will be contextually 3391/// converted to bool. 3392void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3393 Expr **Args, unsigned NumArgs, 3394 OverloadCandidateSet& CandidateSet, 3395 bool IsAssignmentOperator, 3396 unsigned NumContextualBoolArguments) { 3397 // Overload resolution is always an unevaluated context. 3398 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3399 3400 // Add this candidate 3401 CandidateSet.push_back(OverloadCandidate()); 3402 OverloadCandidate& Candidate = CandidateSet.back(); 3403 Candidate.FoundDecl = DeclAccessPair::make(0, AS_none); 3404 Candidate.Function = 0; 3405 Candidate.IsSurrogate = false; 3406 Candidate.IgnoreObjectArgument = false; 3407 Candidate.BuiltinTypes.ResultTy = ResultTy; 3408 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3409 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3410 3411 // Determine the implicit conversion sequences for each of the 3412 // arguments. 3413 Candidate.Viable = true; 3414 Candidate.Conversions.resize(NumArgs); 3415 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3416 // C++ [over.match.oper]p4: 3417 // For the built-in assignment operators, conversions of the 3418 // left operand are restricted as follows: 3419 // -- no temporaries are introduced to hold the left operand, and 3420 // -- no user-defined conversions are applied to the left 3421 // operand to achieve a type match with the left-most 3422 // parameter of a built-in candidate. 3423 // 3424 // We block these conversions by turning off user-defined 3425 // conversions, since that is the only way that initialization of 3426 // a reference to a non-class type can occur from something that 3427 // is not of the same type. 3428 if (ArgIdx < NumContextualBoolArguments) { 3429 assert(ParamTys[ArgIdx] == Context.BoolTy && 3430 "Contextual conversion to bool requires bool type"); 3431 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3432 } else { 3433 Candidate.Conversions[ArgIdx] 3434 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx], 3435 ArgIdx == 0 && IsAssignmentOperator, 3436 /*InOverloadResolution=*/false); 3437 } 3438 if (Candidate.Conversions[ArgIdx].isBad()) { 3439 Candidate.Viable = false; 3440 Candidate.FailureKind = ovl_fail_bad_conversion; 3441 break; 3442 } 3443 } 3444} 3445 3446/// BuiltinCandidateTypeSet - A set of types that will be used for the 3447/// candidate operator functions for built-in operators (C++ 3448/// [over.built]). The types are separated into pointer types and 3449/// enumeration types. 3450class BuiltinCandidateTypeSet { 3451 /// TypeSet - A set of types. 3452 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3453 3454 /// PointerTypes - The set of pointer types that will be used in the 3455 /// built-in candidates. 3456 TypeSet PointerTypes; 3457 3458 /// MemberPointerTypes - The set of member pointer types that will be 3459 /// used in the built-in candidates. 3460 TypeSet MemberPointerTypes; 3461 3462 /// EnumerationTypes - The set of enumeration types that will be 3463 /// used in the built-in candidates. 3464 TypeSet EnumerationTypes; 3465 3466 /// Sema - The semantic analysis instance where we are building the 3467 /// candidate type set. 3468 Sema &SemaRef; 3469 3470 /// Context - The AST context in which we will build the type sets. 3471 ASTContext &Context; 3472 3473 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3474 const Qualifiers &VisibleQuals); 3475 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3476 3477public: 3478 /// iterator - Iterates through the types that are part of the set. 3479 typedef TypeSet::iterator iterator; 3480 3481 BuiltinCandidateTypeSet(Sema &SemaRef) 3482 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3483 3484 void AddTypesConvertedFrom(QualType Ty, 3485 SourceLocation Loc, 3486 bool AllowUserConversions, 3487 bool AllowExplicitConversions, 3488 const Qualifiers &VisibleTypeConversionsQuals); 3489 3490 /// pointer_begin - First pointer type found; 3491 iterator pointer_begin() { return PointerTypes.begin(); } 3492 3493 /// pointer_end - Past the last pointer type found; 3494 iterator pointer_end() { return PointerTypes.end(); } 3495 3496 /// member_pointer_begin - First member pointer type found; 3497 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3498 3499 /// member_pointer_end - Past the last member pointer type found; 3500 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3501 3502 /// enumeration_begin - First enumeration type found; 3503 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3504 3505 /// enumeration_end - Past the last enumeration type found; 3506 iterator enumeration_end() { return EnumerationTypes.end(); } 3507}; 3508 3509/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3510/// the set of pointer types along with any more-qualified variants of 3511/// that type. For example, if @p Ty is "int const *", this routine 3512/// will add "int const *", "int const volatile *", "int const 3513/// restrict *", and "int const volatile restrict *" to the set of 3514/// pointer types. Returns true if the add of @p Ty itself succeeded, 3515/// false otherwise. 3516/// 3517/// FIXME: what to do about extended qualifiers? 3518bool 3519BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3520 const Qualifiers &VisibleQuals) { 3521 3522 // Insert this type. 3523 if (!PointerTypes.insert(Ty)) 3524 return false; 3525 3526 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3527 assert(PointerTy && "type was not a pointer type!"); 3528 3529 QualType PointeeTy = PointerTy->getPointeeType(); 3530 // Don't add qualified variants of arrays. For one, they're not allowed 3531 // (the qualifier would sink to the element type), and for another, the 3532 // only overload situation where it matters is subscript or pointer +- int, 3533 // and those shouldn't have qualifier variants anyway. 3534 if (PointeeTy->isArrayType()) 3535 return true; 3536 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3537 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3538 BaseCVR = Array->getElementType().getCVRQualifiers(); 3539 bool hasVolatile = VisibleQuals.hasVolatile(); 3540 bool hasRestrict = VisibleQuals.hasRestrict(); 3541 3542 // Iterate through all strict supersets of BaseCVR. 3543 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3544 if ((CVR | BaseCVR) != CVR) continue; 3545 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3546 // in the types. 3547 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3548 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3549 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3550 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3551 } 3552 3553 return true; 3554} 3555 3556/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3557/// to the set of pointer types along with any more-qualified variants of 3558/// that type. For example, if @p Ty is "int const *", this routine 3559/// will add "int const *", "int const volatile *", "int const 3560/// restrict *", and "int const volatile restrict *" to the set of 3561/// pointer types. Returns true if the add of @p Ty itself succeeded, 3562/// false otherwise. 3563/// 3564/// FIXME: what to do about extended qualifiers? 3565bool 3566BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3567 QualType Ty) { 3568 // Insert this type. 3569 if (!MemberPointerTypes.insert(Ty)) 3570 return false; 3571 3572 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3573 assert(PointerTy && "type was not a member pointer type!"); 3574 3575 QualType PointeeTy = PointerTy->getPointeeType(); 3576 // Don't add qualified variants of arrays. For one, they're not allowed 3577 // (the qualifier would sink to the element type), and for another, the 3578 // only overload situation where it matters is subscript or pointer +- int, 3579 // and those shouldn't have qualifier variants anyway. 3580 if (PointeeTy->isArrayType()) 3581 return true; 3582 const Type *ClassTy = PointerTy->getClass(); 3583 3584 // Iterate through all strict supersets of the pointee type's CVR 3585 // qualifiers. 3586 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3587 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3588 if ((CVR | BaseCVR) != CVR) continue; 3589 3590 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3591 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3592 } 3593 3594 return true; 3595} 3596 3597/// AddTypesConvertedFrom - Add each of the types to which the type @p 3598/// Ty can be implicit converted to the given set of @p Types. We're 3599/// primarily interested in pointer types and enumeration types. We also 3600/// take member pointer types, for the conditional operator. 3601/// AllowUserConversions is true if we should look at the conversion 3602/// functions of a class type, and AllowExplicitConversions if we 3603/// should also include the explicit conversion functions of a class 3604/// type. 3605void 3606BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3607 SourceLocation Loc, 3608 bool AllowUserConversions, 3609 bool AllowExplicitConversions, 3610 const Qualifiers &VisibleQuals) { 3611 // Only deal with canonical types. 3612 Ty = Context.getCanonicalType(Ty); 3613 3614 // Look through reference types; they aren't part of the type of an 3615 // expression for the purposes of conversions. 3616 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3617 Ty = RefTy->getPointeeType(); 3618 3619 // We don't care about qualifiers on the type. 3620 Ty = Ty.getLocalUnqualifiedType(); 3621 3622 // If we're dealing with an array type, decay to the pointer. 3623 if (Ty->isArrayType()) 3624 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3625 3626 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3627 QualType PointeeTy = PointerTy->getPointeeType(); 3628 3629 // Insert our type, and its more-qualified variants, into the set 3630 // of types. 3631 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3632 return; 3633 } else if (Ty->isMemberPointerType()) { 3634 // Member pointers are far easier, since the pointee can't be converted. 3635 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3636 return; 3637 } else if (Ty->isEnumeralType()) { 3638 EnumerationTypes.insert(Ty); 3639 } else if (AllowUserConversions) { 3640 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3641 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3642 // No conversion functions in incomplete types. 3643 return; 3644 } 3645 3646 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3647 const UnresolvedSetImpl *Conversions 3648 = ClassDecl->getVisibleConversionFunctions(); 3649 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3650 E = Conversions->end(); I != E; ++I) { 3651 NamedDecl *D = I.getDecl(); 3652 if (isa<UsingShadowDecl>(D)) 3653 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3654 3655 // Skip conversion function templates; they don't tell us anything 3656 // about which builtin types we can convert to. 3657 if (isa<FunctionTemplateDecl>(D)) 3658 continue; 3659 3660 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 3661 if (AllowExplicitConversions || !Conv->isExplicit()) { 3662 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3663 VisibleQuals); 3664 } 3665 } 3666 } 3667 } 3668} 3669 3670/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3671/// the volatile- and non-volatile-qualified assignment operators for the 3672/// given type to the candidate set. 3673static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3674 QualType T, 3675 Expr **Args, 3676 unsigned NumArgs, 3677 OverloadCandidateSet &CandidateSet) { 3678 QualType ParamTypes[2]; 3679 3680 // T& operator=(T&, T) 3681 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3682 ParamTypes[1] = T; 3683 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3684 /*IsAssignmentOperator=*/true); 3685 3686 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3687 // volatile T& operator=(volatile T&, T) 3688 ParamTypes[0] 3689 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3690 ParamTypes[1] = T; 3691 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3692 /*IsAssignmentOperator=*/true); 3693 } 3694} 3695 3696/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3697/// if any, found in visible type conversion functions found in ArgExpr's type. 3698static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3699 Qualifiers VRQuals; 3700 const RecordType *TyRec; 3701 if (const MemberPointerType *RHSMPType = 3702 ArgExpr->getType()->getAs<MemberPointerType>()) 3703 TyRec = cast<RecordType>(RHSMPType->getClass()); 3704 else 3705 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3706 if (!TyRec) { 3707 // Just to be safe, assume the worst case. 3708 VRQuals.addVolatile(); 3709 VRQuals.addRestrict(); 3710 return VRQuals; 3711 } 3712 3713 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3714 if (!ClassDecl->hasDefinition()) 3715 return VRQuals; 3716 3717 const UnresolvedSetImpl *Conversions = 3718 ClassDecl->getVisibleConversionFunctions(); 3719 3720 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3721 E = Conversions->end(); I != E; ++I) { 3722 NamedDecl *D = I.getDecl(); 3723 if (isa<UsingShadowDecl>(D)) 3724 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3725 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { 3726 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3727 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3728 CanTy = ResTypeRef->getPointeeType(); 3729 // Need to go down the pointer/mempointer chain and add qualifiers 3730 // as see them. 3731 bool done = false; 3732 while (!done) { 3733 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3734 CanTy = ResTypePtr->getPointeeType(); 3735 else if (const MemberPointerType *ResTypeMPtr = 3736 CanTy->getAs<MemberPointerType>()) 3737 CanTy = ResTypeMPtr->getPointeeType(); 3738 else 3739 done = true; 3740 if (CanTy.isVolatileQualified()) 3741 VRQuals.addVolatile(); 3742 if (CanTy.isRestrictQualified()) 3743 VRQuals.addRestrict(); 3744 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3745 return VRQuals; 3746 } 3747 } 3748 } 3749 return VRQuals; 3750} 3751 3752/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3753/// operator overloads to the candidate set (C++ [over.built]), based 3754/// on the operator @p Op and the arguments given. For example, if the 3755/// operator is a binary '+', this routine might add "int 3756/// operator+(int, int)" to cover integer addition. 3757void 3758Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3759 SourceLocation OpLoc, 3760 Expr **Args, unsigned NumArgs, 3761 OverloadCandidateSet& CandidateSet) { 3762 // The set of "promoted arithmetic types", which are the arithmetic 3763 // types are that preserved by promotion (C++ [over.built]p2). Note 3764 // that the first few of these types are the promoted integral 3765 // types; these types need to be first. 3766 // FIXME: What about complex? 3767 const unsigned FirstIntegralType = 0; 3768 const unsigned LastIntegralType = 13; 3769 const unsigned FirstPromotedIntegralType = 7, 3770 LastPromotedIntegralType = 13; 3771 const unsigned FirstPromotedArithmeticType = 7, 3772 LastPromotedArithmeticType = 16; 3773 const unsigned NumArithmeticTypes = 16; 3774 QualType ArithmeticTypes[NumArithmeticTypes] = { 3775 Context.BoolTy, Context.CharTy, Context.WCharTy, 3776// FIXME: Context.Char16Ty, Context.Char32Ty, 3777 Context.SignedCharTy, Context.ShortTy, 3778 Context.UnsignedCharTy, Context.UnsignedShortTy, 3779 Context.IntTy, Context.LongTy, Context.LongLongTy, 3780 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 3781 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 3782 }; 3783 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 3784 "Invalid first promoted integral type"); 3785 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 3786 == Context.UnsignedLongLongTy && 3787 "Invalid last promoted integral type"); 3788 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 3789 "Invalid first promoted arithmetic type"); 3790 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 3791 == Context.LongDoubleTy && 3792 "Invalid last promoted arithmetic type"); 3793 3794 // Find all of the types that the arguments can convert to, but only 3795 // if the operator we're looking at has built-in operator candidates 3796 // that make use of these types. 3797 Qualifiers VisibleTypeConversionsQuals; 3798 VisibleTypeConversionsQuals.addConst(); 3799 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3800 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 3801 3802 BuiltinCandidateTypeSet CandidateTypes(*this); 3803 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 3804 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 3805 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 3806 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 3807 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 3808 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 3809 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3810 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 3811 OpLoc, 3812 true, 3813 (Op == OO_Exclaim || 3814 Op == OO_AmpAmp || 3815 Op == OO_PipePipe), 3816 VisibleTypeConversionsQuals); 3817 } 3818 3819 bool isComparison = false; 3820 switch (Op) { 3821 case OO_None: 3822 case NUM_OVERLOADED_OPERATORS: 3823 assert(false && "Expected an overloaded operator"); 3824 break; 3825 3826 case OO_Star: // '*' is either unary or binary 3827 if (NumArgs == 1) 3828 goto UnaryStar; 3829 else 3830 goto BinaryStar; 3831 break; 3832 3833 case OO_Plus: // '+' is either unary or binary 3834 if (NumArgs == 1) 3835 goto UnaryPlus; 3836 else 3837 goto BinaryPlus; 3838 break; 3839 3840 case OO_Minus: // '-' is either unary or binary 3841 if (NumArgs == 1) 3842 goto UnaryMinus; 3843 else 3844 goto BinaryMinus; 3845 break; 3846 3847 case OO_Amp: // '&' is either unary or binary 3848 if (NumArgs == 1) 3849 goto UnaryAmp; 3850 else 3851 goto BinaryAmp; 3852 3853 case OO_PlusPlus: 3854 case OO_MinusMinus: 3855 // C++ [over.built]p3: 3856 // 3857 // For every pair (T, VQ), where T is an arithmetic type, and VQ 3858 // is either volatile or empty, there exist candidate operator 3859 // functions of the form 3860 // 3861 // VQ T& operator++(VQ T&); 3862 // T operator++(VQ T&, int); 3863 // 3864 // C++ [over.built]p4: 3865 // 3866 // For every pair (T, VQ), where T is an arithmetic type other 3867 // than bool, and VQ is either volatile or empty, there exist 3868 // candidate operator functions of the form 3869 // 3870 // VQ T& operator--(VQ T&); 3871 // T operator--(VQ T&, int); 3872 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 3873 Arith < NumArithmeticTypes; ++Arith) { 3874 QualType ArithTy = ArithmeticTypes[Arith]; 3875 QualType ParamTypes[2] 3876 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 3877 3878 // Non-volatile version. 3879 if (NumArgs == 1) 3880 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3881 else 3882 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3883 // heuristic to reduce number of builtin candidates in the set. 3884 // Add volatile version only if there are conversions to a volatile type. 3885 if (VisibleTypeConversionsQuals.hasVolatile()) { 3886 // Volatile version 3887 ParamTypes[0] 3888 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 3889 if (NumArgs == 1) 3890 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3891 else 3892 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3893 } 3894 } 3895 3896 // C++ [over.built]p5: 3897 // 3898 // For every pair (T, VQ), where T is a cv-qualified or 3899 // cv-unqualified object type, and VQ is either volatile or 3900 // empty, there exist candidate operator functions of the form 3901 // 3902 // T*VQ& operator++(T*VQ&); 3903 // T*VQ& operator--(T*VQ&); 3904 // T* operator++(T*VQ&, int); 3905 // T* operator--(T*VQ&, int); 3906 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3907 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3908 // Skip pointer types that aren't pointers to object types. 3909 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 3910 continue; 3911 3912 QualType ParamTypes[2] = { 3913 Context.getLValueReferenceType(*Ptr), Context.IntTy 3914 }; 3915 3916 // Without volatile 3917 if (NumArgs == 1) 3918 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3919 else 3920 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3921 3922 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 3923 VisibleTypeConversionsQuals.hasVolatile()) { 3924 // With volatile 3925 ParamTypes[0] 3926 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 3927 if (NumArgs == 1) 3928 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3929 else 3930 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3931 } 3932 } 3933 break; 3934 3935 UnaryStar: 3936 // C++ [over.built]p6: 3937 // For every cv-qualified or cv-unqualified object type T, there 3938 // exist candidate operator functions of the form 3939 // 3940 // T& operator*(T*); 3941 // 3942 // C++ [over.built]p7: 3943 // For every function type T, there exist candidate operator 3944 // functions of the form 3945 // T& operator*(T*); 3946 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3947 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3948 QualType ParamTy = *Ptr; 3949 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 3950 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 3951 &ParamTy, Args, 1, CandidateSet); 3952 } 3953 break; 3954 3955 UnaryPlus: 3956 // C++ [over.built]p8: 3957 // For every type T, there exist candidate operator functions of 3958 // the form 3959 // 3960 // T* operator+(T*); 3961 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3962 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3963 QualType ParamTy = *Ptr; 3964 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 3965 } 3966 3967 // Fall through 3968 3969 UnaryMinus: 3970 // C++ [over.built]p9: 3971 // For every promoted arithmetic type T, there exist candidate 3972 // operator functions of the form 3973 // 3974 // T operator+(T); 3975 // T operator-(T); 3976 for (unsigned Arith = FirstPromotedArithmeticType; 3977 Arith < LastPromotedArithmeticType; ++Arith) { 3978 QualType ArithTy = ArithmeticTypes[Arith]; 3979 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 3980 } 3981 break; 3982 3983 case OO_Tilde: 3984 // C++ [over.built]p10: 3985 // For every promoted integral type T, there exist candidate 3986 // operator functions of the form 3987 // 3988 // T operator~(T); 3989 for (unsigned Int = FirstPromotedIntegralType; 3990 Int < LastPromotedIntegralType; ++Int) { 3991 QualType IntTy = ArithmeticTypes[Int]; 3992 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 3993 } 3994 break; 3995 3996 case OO_New: 3997 case OO_Delete: 3998 case OO_Array_New: 3999 case OO_Array_Delete: 4000 case OO_Call: 4001 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 4002 break; 4003 4004 case OO_Comma: 4005 UnaryAmp: 4006 case OO_Arrow: 4007 // C++ [over.match.oper]p3: 4008 // -- For the operator ',', the unary operator '&', or the 4009 // operator '->', the built-in candidates set is empty. 4010 break; 4011 4012 case OO_EqualEqual: 4013 case OO_ExclaimEqual: 4014 // C++ [over.match.oper]p16: 4015 // For every pointer to member type T, there exist candidate operator 4016 // functions of the form 4017 // 4018 // bool operator==(T,T); 4019 // bool operator!=(T,T); 4020 for (BuiltinCandidateTypeSet::iterator 4021 MemPtr = CandidateTypes.member_pointer_begin(), 4022 MemPtrEnd = CandidateTypes.member_pointer_end(); 4023 MemPtr != MemPtrEnd; 4024 ++MemPtr) { 4025 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 4026 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4027 } 4028 4029 // Fall through 4030 4031 case OO_Less: 4032 case OO_Greater: 4033 case OO_LessEqual: 4034 case OO_GreaterEqual: 4035 // C++ [over.built]p15: 4036 // 4037 // For every pointer or enumeration type T, there exist 4038 // candidate operator functions of the form 4039 // 4040 // bool operator<(T, T); 4041 // bool operator>(T, T); 4042 // bool operator<=(T, T); 4043 // bool operator>=(T, T); 4044 // bool operator==(T, T); 4045 // bool operator!=(T, T); 4046 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4047 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4048 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4049 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4050 } 4051 for (BuiltinCandidateTypeSet::iterator Enum 4052 = CandidateTypes.enumeration_begin(); 4053 Enum != CandidateTypes.enumeration_end(); ++Enum) { 4054 QualType ParamTypes[2] = { *Enum, *Enum }; 4055 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4056 } 4057 4058 // Fall through. 4059 isComparison = true; 4060 4061 BinaryPlus: 4062 BinaryMinus: 4063 if (!isComparison) { 4064 // We didn't fall through, so we must have OO_Plus or OO_Minus. 4065 4066 // C++ [over.built]p13: 4067 // 4068 // For every cv-qualified or cv-unqualified object type T 4069 // there exist candidate operator functions of the form 4070 // 4071 // T* operator+(T*, ptrdiff_t); 4072 // T& operator[](T*, ptrdiff_t); [BELOW] 4073 // T* operator-(T*, ptrdiff_t); 4074 // T* operator+(ptrdiff_t, T*); 4075 // T& operator[](ptrdiff_t, T*); [BELOW] 4076 // 4077 // C++ [over.built]p14: 4078 // 4079 // For every T, where T is a pointer to object type, there 4080 // exist candidate operator functions of the form 4081 // 4082 // ptrdiff_t operator-(T, T); 4083 for (BuiltinCandidateTypeSet::iterator Ptr 4084 = CandidateTypes.pointer_begin(); 4085 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4086 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4087 4088 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 4089 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4090 4091 if (Op == OO_Plus) { 4092 // T* operator+(ptrdiff_t, T*); 4093 ParamTypes[0] = ParamTypes[1]; 4094 ParamTypes[1] = *Ptr; 4095 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4096 } else { 4097 // ptrdiff_t operator-(T, T); 4098 ParamTypes[1] = *Ptr; 4099 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 4100 Args, 2, CandidateSet); 4101 } 4102 } 4103 } 4104 // Fall through 4105 4106 case OO_Slash: 4107 BinaryStar: 4108 Conditional: 4109 // C++ [over.built]p12: 4110 // 4111 // For every pair of promoted arithmetic types L and R, there 4112 // exist candidate operator functions of the form 4113 // 4114 // LR operator*(L, R); 4115 // LR operator/(L, R); 4116 // LR operator+(L, R); 4117 // LR operator-(L, R); 4118 // bool operator<(L, R); 4119 // bool operator>(L, R); 4120 // bool operator<=(L, R); 4121 // bool operator>=(L, R); 4122 // bool operator==(L, R); 4123 // bool operator!=(L, R); 4124 // 4125 // where LR is the result of the usual arithmetic conversions 4126 // between types L and R. 4127 // 4128 // C++ [over.built]p24: 4129 // 4130 // For every pair of promoted arithmetic types L and R, there exist 4131 // candidate operator functions of the form 4132 // 4133 // LR operator?(bool, L, R); 4134 // 4135 // where LR is the result of the usual arithmetic conversions 4136 // between types L and R. 4137 // Our candidates ignore the first parameter. 4138 for (unsigned Left = FirstPromotedArithmeticType; 4139 Left < LastPromotedArithmeticType; ++Left) { 4140 for (unsigned Right = FirstPromotedArithmeticType; 4141 Right < LastPromotedArithmeticType; ++Right) { 4142 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4143 QualType Result 4144 = isComparison 4145 ? Context.BoolTy 4146 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4147 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4148 } 4149 } 4150 break; 4151 4152 case OO_Percent: 4153 BinaryAmp: 4154 case OO_Caret: 4155 case OO_Pipe: 4156 case OO_LessLess: 4157 case OO_GreaterGreater: 4158 // C++ [over.built]p17: 4159 // 4160 // For every pair of promoted integral types L and R, there 4161 // exist candidate operator functions of the form 4162 // 4163 // LR operator%(L, R); 4164 // LR operator&(L, R); 4165 // LR operator^(L, R); 4166 // LR operator|(L, R); 4167 // L operator<<(L, R); 4168 // L operator>>(L, R); 4169 // 4170 // where LR is the result of the usual arithmetic conversions 4171 // between types L and R. 4172 for (unsigned Left = FirstPromotedIntegralType; 4173 Left < LastPromotedIntegralType; ++Left) { 4174 for (unsigned Right = FirstPromotedIntegralType; 4175 Right < LastPromotedIntegralType; ++Right) { 4176 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4177 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 4178 ? LandR[0] 4179 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4180 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4181 } 4182 } 4183 break; 4184 4185 case OO_Equal: 4186 // C++ [over.built]p20: 4187 // 4188 // For every pair (T, VQ), where T is an enumeration or 4189 // pointer to member type and VQ is either volatile or 4190 // empty, there exist candidate operator functions of the form 4191 // 4192 // VQ T& operator=(VQ T&, T); 4193 for (BuiltinCandidateTypeSet::iterator 4194 Enum = CandidateTypes.enumeration_begin(), 4195 EnumEnd = CandidateTypes.enumeration_end(); 4196 Enum != EnumEnd; ++Enum) 4197 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 4198 CandidateSet); 4199 for (BuiltinCandidateTypeSet::iterator 4200 MemPtr = CandidateTypes.member_pointer_begin(), 4201 MemPtrEnd = CandidateTypes.member_pointer_end(); 4202 MemPtr != MemPtrEnd; ++MemPtr) 4203 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 4204 CandidateSet); 4205 // Fall through. 4206 4207 case OO_PlusEqual: 4208 case OO_MinusEqual: 4209 // C++ [over.built]p19: 4210 // 4211 // For every pair (T, VQ), where T is any type and VQ is either 4212 // volatile or empty, there exist candidate operator functions 4213 // of the form 4214 // 4215 // T*VQ& operator=(T*VQ&, T*); 4216 // 4217 // C++ [over.built]p21: 4218 // 4219 // For every pair (T, VQ), where T is a cv-qualified or 4220 // cv-unqualified object type and VQ is either volatile or 4221 // empty, there exist candidate operator functions of the form 4222 // 4223 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 4224 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 4225 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4226 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4227 QualType ParamTypes[2]; 4228 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 4229 4230 // non-volatile version 4231 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 4232 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4233 /*IsAssigmentOperator=*/Op == OO_Equal); 4234 4235 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4236 VisibleTypeConversionsQuals.hasVolatile()) { 4237 // volatile version 4238 ParamTypes[0] 4239 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4240 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4241 /*IsAssigmentOperator=*/Op == OO_Equal); 4242 } 4243 } 4244 // Fall through. 4245 4246 case OO_StarEqual: 4247 case OO_SlashEqual: 4248 // C++ [over.built]p18: 4249 // 4250 // For every triple (L, VQ, R), where L is an arithmetic type, 4251 // VQ is either volatile or empty, and R is a promoted 4252 // arithmetic type, there exist candidate operator functions of 4253 // the form 4254 // 4255 // VQ L& operator=(VQ L&, R); 4256 // VQ L& operator*=(VQ L&, R); 4257 // VQ L& operator/=(VQ L&, R); 4258 // VQ L& operator+=(VQ L&, R); 4259 // VQ L& operator-=(VQ L&, R); 4260 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 4261 for (unsigned Right = FirstPromotedArithmeticType; 4262 Right < LastPromotedArithmeticType; ++Right) { 4263 QualType ParamTypes[2]; 4264 ParamTypes[1] = ArithmeticTypes[Right]; 4265 4266 // Add this built-in operator as a candidate (VQ is empty). 4267 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4268 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4269 /*IsAssigmentOperator=*/Op == OO_Equal); 4270 4271 // Add this built-in operator as a candidate (VQ is 'volatile'). 4272 if (VisibleTypeConversionsQuals.hasVolatile()) { 4273 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 4274 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4275 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4276 /*IsAssigmentOperator=*/Op == OO_Equal); 4277 } 4278 } 4279 } 4280 break; 4281 4282 case OO_PercentEqual: 4283 case OO_LessLessEqual: 4284 case OO_GreaterGreaterEqual: 4285 case OO_AmpEqual: 4286 case OO_CaretEqual: 4287 case OO_PipeEqual: 4288 // C++ [over.built]p22: 4289 // 4290 // For every triple (L, VQ, R), where L is an integral type, VQ 4291 // is either volatile or empty, and R is a promoted integral 4292 // type, there exist candidate operator functions of the form 4293 // 4294 // VQ L& operator%=(VQ L&, R); 4295 // VQ L& operator<<=(VQ L&, R); 4296 // VQ L& operator>>=(VQ L&, R); 4297 // VQ L& operator&=(VQ L&, R); 4298 // VQ L& operator^=(VQ L&, R); 4299 // VQ L& operator|=(VQ L&, R); 4300 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 4301 for (unsigned Right = FirstPromotedIntegralType; 4302 Right < LastPromotedIntegralType; ++Right) { 4303 QualType ParamTypes[2]; 4304 ParamTypes[1] = ArithmeticTypes[Right]; 4305 4306 // Add this built-in operator as a candidate (VQ is empty). 4307 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4308 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4309 if (VisibleTypeConversionsQuals.hasVolatile()) { 4310 // Add this built-in operator as a candidate (VQ is 'volatile'). 4311 ParamTypes[0] = ArithmeticTypes[Left]; 4312 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 4313 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4314 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4315 } 4316 } 4317 } 4318 break; 4319 4320 case OO_Exclaim: { 4321 // C++ [over.operator]p23: 4322 // 4323 // There also exist candidate operator functions of the form 4324 // 4325 // bool operator!(bool); 4326 // bool operator&&(bool, bool); [BELOW] 4327 // bool operator||(bool, bool); [BELOW] 4328 QualType ParamTy = Context.BoolTy; 4329 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 4330 /*IsAssignmentOperator=*/false, 4331 /*NumContextualBoolArguments=*/1); 4332 break; 4333 } 4334 4335 case OO_AmpAmp: 4336 case OO_PipePipe: { 4337 // C++ [over.operator]p23: 4338 // 4339 // There also exist candidate operator functions of the form 4340 // 4341 // bool operator!(bool); [ABOVE] 4342 // bool operator&&(bool, bool); 4343 // bool operator||(bool, bool); 4344 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 4345 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 4346 /*IsAssignmentOperator=*/false, 4347 /*NumContextualBoolArguments=*/2); 4348 break; 4349 } 4350 4351 case OO_Subscript: 4352 // C++ [over.built]p13: 4353 // 4354 // For every cv-qualified or cv-unqualified object type T there 4355 // exist candidate operator functions of the form 4356 // 4357 // T* operator+(T*, ptrdiff_t); [ABOVE] 4358 // T& operator[](T*, ptrdiff_t); 4359 // T* operator-(T*, ptrdiff_t); [ABOVE] 4360 // T* operator+(ptrdiff_t, T*); [ABOVE] 4361 // T& operator[](ptrdiff_t, T*); 4362 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4363 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4364 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4365 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 4366 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 4367 4368 // T& operator[](T*, ptrdiff_t) 4369 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4370 4371 // T& operator[](ptrdiff_t, T*); 4372 ParamTypes[0] = ParamTypes[1]; 4373 ParamTypes[1] = *Ptr; 4374 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4375 } 4376 break; 4377 4378 case OO_ArrowStar: 4379 // C++ [over.built]p11: 4380 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 4381 // C1 is the same type as C2 or is a derived class of C2, T is an object 4382 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 4383 // there exist candidate operator functions of the form 4384 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 4385 // where CV12 is the union of CV1 and CV2. 4386 { 4387 for (BuiltinCandidateTypeSet::iterator Ptr = 4388 CandidateTypes.pointer_begin(); 4389 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4390 QualType C1Ty = (*Ptr); 4391 QualType C1; 4392 QualifierCollector Q1; 4393 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 4394 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 4395 if (!isa<RecordType>(C1)) 4396 continue; 4397 // heuristic to reduce number of builtin candidates in the set. 4398 // Add volatile/restrict version only if there are conversions to a 4399 // volatile/restrict type. 4400 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 4401 continue; 4402 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4403 continue; 4404 } 4405 for (BuiltinCandidateTypeSet::iterator 4406 MemPtr = CandidateTypes.member_pointer_begin(), 4407 MemPtrEnd = CandidateTypes.member_pointer_end(); 4408 MemPtr != MemPtrEnd; ++MemPtr) { 4409 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4410 QualType C2 = QualType(mptr->getClass(), 0); 4411 C2 = C2.getUnqualifiedType(); 4412 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4413 break; 4414 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4415 // build CV12 T& 4416 QualType T = mptr->getPointeeType(); 4417 if (!VisibleTypeConversionsQuals.hasVolatile() && 4418 T.isVolatileQualified()) 4419 continue; 4420 if (!VisibleTypeConversionsQuals.hasRestrict() && 4421 T.isRestrictQualified()) 4422 continue; 4423 T = Q1.apply(T); 4424 QualType ResultTy = Context.getLValueReferenceType(T); 4425 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4426 } 4427 } 4428 } 4429 break; 4430 4431 case OO_Conditional: 4432 // Note that we don't consider the first argument, since it has been 4433 // contextually converted to bool long ago. The candidates below are 4434 // therefore added as binary. 4435 // 4436 // C++ [over.built]p24: 4437 // For every type T, where T is a pointer or pointer-to-member type, 4438 // there exist candidate operator functions of the form 4439 // 4440 // T operator?(bool, T, T); 4441 // 4442 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4443 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4444 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4445 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4446 } 4447 for (BuiltinCandidateTypeSet::iterator Ptr = 4448 CandidateTypes.member_pointer_begin(), 4449 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4450 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4451 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4452 } 4453 goto Conditional; 4454 } 4455} 4456 4457/// \brief Add function candidates found via argument-dependent lookup 4458/// to the set of overloading candidates. 4459/// 4460/// This routine performs argument-dependent name lookup based on the 4461/// given function name (which may also be an operator name) and adds 4462/// all of the overload candidates found by ADL to the overload 4463/// candidate set (C++ [basic.lookup.argdep]). 4464void 4465Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4466 bool Operator, 4467 Expr **Args, unsigned NumArgs, 4468 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4469 OverloadCandidateSet& CandidateSet, 4470 bool PartialOverloading) { 4471 ADLResult Fns; 4472 4473 // FIXME: This approach for uniquing ADL results (and removing 4474 // redundant candidates from the set) relies on pointer-equality, 4475 // which means we need to key off the canonical decl. However, 4476 // always going back to the canonical decl might not get us the 4477 // right set of default arguments. What default arguments are 4478 // we supposed to consider on ADL candidates, anyway? 4479 4480 // FIXME: Pass in the explicit template arguments? 4481 ArgumentDependentLookup(Name, Operator, Args, NumArgs, Fns); 4482 4483 // Erase all of the candidates we already knew about. 4484 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4485 CandEnd = CandidateSet.end(); 4486 Cand != CandEnd; ++Cand) 4487 if (Cand->Function) { 4488 Fns.erase(Cand->Function); 4489 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4490 Fns.erase(FunTmpl); 4491 } 4492 4493 // For each of the ADL candidates we found, add it to the overload 4494 // set. 4495 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 4496 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); 4497 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 4498 if (ExplicitTemplateArgs) 4499 continue; 4500 4501 AddOverloadCandidate(FD, FoundDecl, Args, NumArgs, CandidateSet, 4502 false, PartialOverloading); 4503 } else 4504 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), 4505 FoundDecl, ExplicitTemplateArgs, 4506 Args, NumArgs, CandidateSet); 4507 } 4508} 4509 4510/// isBetterOverloadCandidate - Determines whether the first overload 4511/// candidate is a better candidate than the second (C++ 13.3.3p1). 4512bool 4513Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4514 const OverloadCandidate& Cand2, 4515 SourceLocation Loc) { 4516 // Define viable functions to be better candidates than non-viable 4517 // functions. 4518 if (!Cand2.Viable) 4519 return Cand1.Viable; 4520 else if (!Cand1.Viable) 4521 return false; 4522 4523 // C++ [over.match.best]p1: 4524 // 4525 // -- if F is a static member function, ICS1(F) is defined such 4526 // that ICS1(F) is neither better nor worse than ICS1(G) for 4527 // any function G, and, symmetrically, ICS1(G) is neither 4528 // better nor worse than ICS1(F). 4529 unsigned StartArg = 0; 4530 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4531 StartArg = 1; 4532 4533 // C++ [over.match.best]p1: 4534 // A viable function F1 is defined to be a better function than another 4535 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4536 // conversion sequence than ICSi(F2), and then... 4537 unsigned NumArgs = Cand1.Conversions.size(); 4538 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4539 bool HasBetterConversion = false; 4540 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4541 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4542 Cand2.Conversions[ArgIdx])) { 4543 case ImplicitConversionSequence::Better: 4544 // Cand1 has a better conversion sequence. 4545 HasBetterConversion = true; 4546 break; 4547 4548 case ImplicitConversionSequence::Worse: 4549 // Cand1 can't be better than Cand2. 4550 return false; 4551 4552 case ImplicitConversionSequence::Indistinguishable: 4553 // Do nothing. 4554 break; 4555 } 4556 } 4557 4558 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4559 // ICSj(F2), or, if not that, 4560 if (HasBetterConversion) 4561 return true; 4562 4563 // - F1 is a non-template function and F2 is a function template 4564 // specialization, or, if not that, 4565 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4566 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4567 return true; 4568 4569 // -- F1 and F2 are function template specializations, and the function 4570 // template for F1 is more specialized than the template for F2 4571 // according to the partial ordering rules described in 14.5.5.2, or, 4572 // if not that, 4573 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4574 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4575 if (FunctionTemplateDecl *BetterTemplate 4576 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4577 Cand2.Function->getPrimaryTemplate(), 4578 Loc, 4579 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4580 : TPOC_Call)) 4581 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4582 4583 // -- the context is an initialization by user-defined conversion 4584 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4585 // from the return type of F1 to the destination type (i.e., 4586 // the type of the entity being initialized) is a better 4587 // conversion sequence than the standard conversion sequence 4588 // from the return type of F2 to the destination type. 4589 if (Cand1.Function && Cand2.Function && 4590 isa<CXXConversionDecl>(Cand1.Function) && 4591 isa<CXXConversionDecl>(Cand2.Function)) { 4592 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4593 Cand2.FinalConversion)) { 4594 case ImplicitConversionSequence::Better: 4595 // Cand1 has a better conversion sequence. 4596 return true; 4597 4598 case ImplicitConversionSequence::Worse: 4599 // Cand1 can't be better than Cand2. 4600 return false; 4601 4602 case ImplicitConversionSequence::Indistinguishable: 4603 // Do nothing 4604 break; 4605 } 4606 } 4607 4608 return false; 4609} 4610 4611/// \brief Computes the best viable function (C++ 13.3.3) 4612/// within an overload candidate set. 4613/// 4614/// \param CandidateSet the set of candidate functions. 4615/// 4616/// \param Loc the location of the function name (or operator symbol) for 4617/// which overload resolution occurs. 4618/// 4619/// \param Best f overload resolution was successful or found a deleted 4620/// function, Best points to the candidate function found. 4621/// 4622/// \returns The result of overload resolution. 4623OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4624 SourceLocation Loc, 4625 OverloadCandidateSet::iterator& Best) { 4626 // Find the best viable function. 4627 Best = CandidateSet.end(); 4628 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4629 Cand != CandidateSet.end(); ++Cand) { 4630 if (Cand->Viable) { 4631 if (Best == CandidateSet.end() || 4632 isBetterOverloadCandidate(*Cand, *Best, Loc)) 4633 Best = Cand; 4634 } 4635 } 4636 4637 // If we didn't find any viable functions, abort. 4638 if (Best == CandidateSet.end()) 4639 return OR_No_Viable_Function; 4640 4641 // Make sure that this function is better than every other viable 4642 // function. If not, we have an ambiguity. 4643 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4644 Cand != CandidateSet.end(); ++Cand) { 4645 if (Cand->Viable && 4646 Cand != Best && 4647 !isBetterOverloadCandidate(*Best, *Cand, Loc)) { 4648 Best = CandidateSet.end(); 4649 return OR_Ambiguous; 4650 } 4651 } 4652 4653 // Best is the best viable function. 4654 if (Best->Function && 4655 (Best->Function->isDeleted() || 4656 Best->Function->getAttr<UnavailableAttr>())) 4657 return OR_Deleted; 4658 4659 // C++ [basic.def.odr]p2: 4660 // An overloaded function is used if it is selected by overload resolution 4661 // when referred to from a potentially-evaluated expression. [Note: this 4662 // covers calls to named functions (5.2.2), operator overloading 4663 // (clause 13), user-defined conversions (12.3.2), allocation function for 4664 // placement new (5.3.4), as well as non-default initialization (8.5). 4665 if (Best->Function) 4666 MarkDeclarationReferenced(Loc, Best->Function); 4667 return OR_Success; 4668} 4669 4670namespace { 4671 4672enum OverloadCandidateKind { 4673 oc_function, 4674 oc_method, 4675 oc_constructor, 4676 oc_function_template, 4677 oc_method_template, 4678 oc_constructor_template, 4679 oc_implicit_default_constructor, 4680 oc_implicit_copy_constructor, 4681 oc_implicit_copy_assignment 4682}; 4683 4684OverloadCandidateKind ClassifyOverloadCandidate(Sema &S, 4685 FunctionDecl *Fn, 4686 std::string &Description) { 4687 bool isTemplate = false; 4688 4689 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { 4690 isTemplate = true; 4691 Description = S.getTemplateArgumentBindingsText( 4692 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); 4693 } 4694 4695 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4696 if (!Ctor->isImplicit()) 4697 return isTemplate ? oc_constructor_template : oc_constructor; 4698 4699 return Ctor->isCopyConstructor() ? oc_implicit_copy_constructor 4700 : oc_implicit_default_constructor; 4701 } 4702 4703 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4704 // This actually gets spelled 'candidate function' for now, but 4705 // it doesn't hurt to split it out. 4706 if (!Meth->isImplicit()) 4707 return isTemplate ? oc_method_template : oc_method; 4708 4709 assert(Meth->isCopyAssignment() 4710 && "implicit method is not copy assignment operator?"); 4711 return oc_implicit_copy_assignment; 4712 } 4713 4714 return isTemplate ? oc_function_template : oc_function; 4715} 4716 4717} // end anonymous namespace 4718 4719// Notes the location of an overload candidate. 4720void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4721 std::string FnDesc; 4722 OverloadCandidateKind K = ClassifyOverloadCandidate(*this, Fn, FnDesc); 4723 Diag(Fn->getLocation(), diag::note_ovl_candidate) 4724 << (unsigned) K << FnDesc; 4725} 4726 4727/// Diagnoses an ambiguous conversion. The partial diagnostic is the 4728/// "lead" diagnostic; it will be given two arguments, the source and 4729/// target types of the conversion. 4730void Sema::DiagnoseAmbiguousConversion(const ImplicitConversionSequence &ICS, 4731 SourceLocation CaretLoc, 4732 const PartialDiagnostic &PDiag) { 4733 Diag(CaretLoc, PDiag) 4734 << ICS.Ambiguous.getFromType() << ICS.Ambiguous.getToType(); 4735 for (AmbiguousConversionSequence::const_iterator 4736 I = ICS.Ambiguous.begin(), E = ICS.Ambiguous.end(); I != E; ++I) { 4737 NoteOverloadCandidate(*I); 4738 } 4739} 4740 4741namespace { 4742 4743void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I) { 4744 const ImplicitConversionSequence &Conv = Cand->Conversions[I]; 4745 assert(Conv.isBad()); 4746 assert(Cand->Function && "for now, candidate must be a function"); 4747 FunctionDecl *Fn = Cand->Function; 4748 4749 // There's a conversion slot for the object argument if this is a 4750 // non-constructor method. Note that 'I' corresponds the 4751 // conversion-slot index. 4752 bool isObjectArgument = false; 4753 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { 4754 if (I == 0) 4755 isObjectArgument = true; 4756 else 4757 I--; 4758 } 4759 4760 std::string FnDesc; 4761 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4762 4763 Expr *FromExpr = Conv.Bad.FromExpr; 4764 QualType FromTy = Conv.Bad.getFromType(); 4765 QualType ToTy = Conv.Bad.getToType(); 4766 4767 if (FromTy == S.Context.OverloadTy) { 4768 assert(FromExpr && "overload set argument came from implicit argument?"); 4769 Expr *E = FromExpr->IgnoreParens(); 4770 if (isa<UnaryOperator>(E)) 4771 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 4772 DeclarationName Name = cast<OverloadExpr>(E)->getName(); 4773 4774 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) 4775 << (unsigned) FnKind << FnDesc 4776 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4777 << ToTy << Name << I+1; 4778 return; 4779 } 4780 4781 // Do some hand-waving analysis to see if the non-viability is due 4782 // to a qualifier mismatch. 4783 CanQualType CFromTy = S.Context.getCanonicalType(FromTy); 4784 CanQualType CToTy = S.Context.getCanonicalType(ToTy); 4785 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) 4786 CToTy = RT->getPointeeType(); 4787 else { 4788 // TODO: detect and diagnose the full richness of const mismatches. 4789 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) 4790 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) 4791 CFromTy = FromPT->getPointeeType(), CToTy = ToPT->getPointeeType(); 4792 } 4793 4794 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && 4795 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { 4796 // It is dumb that we have to do this here. 4797 while (isa<ArrayType>(CFromTy)) 4798 CFromTy = CFromTy->getAs<ArrayType>()->getElementType(); 4799 while (isa<ArrayType>(CToTy)) 4800 CToTy = CFromTy->getAs<ArrayType>()->getElementType(); 4801 4802 Qualifiers FromQs = CFromTy.getQualifiers(); 4803 Qualifiers ToQs = CToTy.getQualifiers(); 4804 4805 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { 4806 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) 4807 << (unsigned) FnKind << FnDesc 4808 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4809 << FromTy 4810 << FromQs.getAddressSpace() << ToQs.getAddressSpace() 4811 << (unsigned) isObjectArgument << I+1; 4812 return; 4813 } 4814 4815 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); 4816 assert(CVR && "unexpected qualifiers mismatch"); 4817 4818 if (isObjectArgument) { 4819 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) 4820 << (unsigned) FnKind << FnDesc 4821 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4822 << FromTy << (CVR - 1); 4823 } else { 4824 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) 4825 << (unsigned) FnKind << FnDesc 4826 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4827 << FromTy << (CVR - 1) << I+1; 4828 } 4829 return; 4830 } 4831 4832 // Diagnose references or pointers to incomplete types differently, 4833 // since it's far from impossible that the incompleteness triggered 4834 // the failure. 4835 QualType TempFromTy = FromTy.getNonReferenceType(); 4836 if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) 4837 TempFromTy = PTy->getPointeeType(); 4838 if (TempFromTy->isIncompleteType()) { 4839 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) 4840 << (unsigned) FnKind << FnDesc 4841 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4842 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4843 return; 4844 } 4845 4846 // TODO: specialize more based on the kind of mismatch 4847 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv) 4848 << (unsigned) FnKind << FnDesc 4849 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4850 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4851} 4852 4853void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, 4854 unsigned NumFormalArgs) { 4855 // TODO: treat calls to a missing default constructor as a special case 4856 4857 FunctionDecl *Fn = Cand->Function; 4858 const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); 4859 4860 unsigned MinParams = Fn->getMinRequiredArguments(); 4861 4862 // at least / at most / exactly 4863 unsigned mode, modeCount; 4864 if (NumFormalArgs < MinParams) { 4865 assert(Cand->FailureKind == ovl_fail_too_few_arguments); 4866 if (MinParams != FnTy->getNumArgs() || FnTy->isVariadic()) 4867 mode = 0; // "at least" 4868 else 4869 mode = 2; // "exactly" 4870 modeCount = MinParams; 4871 } else { 4872 assert(Cand->FailureKind == ovl_fail_too_many_arguments); 4873 if (MinParams != FnTy->getNumArgs()) 4874 mode = 1; // "at most" 4875 else 4876 mode = 2; // "exactly" 4877 modeCount = FnTy->getNumArgs(); 4878 } 4879 4880 std::string Description; 4881 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, Description); 4882 4883 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) 4884 << (unsigned) FnKind << Description << mode << modeCount << NumFormalArgs; 4885} 4886 4887/// Diagnose a failed template-argument deduction. 4888void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, 4889 Expr **Args, unsigned NumArgs) { 4890 FunctionDecl *Fn = Cand->Function; // pattern 4891 4892 TemplateParameter Param = TemplateParameter::getFromOpaqueValue( 4893 Cand->DeductionFailure.TemplateParameter); 4894 4895 switch (Cand->DeductionFailure.Result) { 4896 case Sema::TDK_Success: 4897 llvm_unreachable("TDK_success while diagnosing bad deduction"); 4898 4899 case Sema::TDK_Incomplete: { 4900 NamedDecl *ParamD; 4901 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || 4902 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || 4903 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); 4904 assert(ParamD && "no parameter found for incomplete deduction result"); 4905 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_incomplete_deduction) 4906 << ParamD->getDeclName(); 4907 return; 4908 } 4909 4910 // TODO: diagnose these individually, then kill off 4911 // note_ovl_candidate_bad_deduction, which is uselessly vague. 4912 case Sema::TDK_InstantiationDepth: 4913 case Sema::TDK_Inconsistent: 4914 case Sema::TDK_InconsistentQuals: 4915 case Sema::TDK_SubstitutionFailure: 4916 case Sema::TDK_NonDeducedMismatch: 4917 case Sema::TDK_TooManyArguments: 4918 case Sema::TDK_TooFewArguments: 4919 case Sema::TDK_InvalidExplicitArguments: 4920 case Sema::TDK_FailedOverloadResolution: 4921 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction); 4922 return; 4923 } 4924} 4925 4926/// Generates a 'note' diagnostic for an overload candidate. We've 4927/// already generated a primary error at the call site. 4928/// 4929/// It really does need to be a single diagnostic with its caret 4930/// pointed at the candidate declaration. Yes, this creates some 4931/// major challenges of technical writing. Yes, this makes pointing 4932/// out problems with specific arguments quite awkward. It's still 4933/// better than generating twenty screens of text for every failed 4934/// overload. 4935/// 4936/// It would be great to be able to express per-candidate problems 4937/// more richly for those diagnostic clients that cared, but we'd 4938/// still have to be just as careful with the default diagnostics. 4939void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, 4940 Expr **Args, unsigned NumArgs) { 4941 FunctionDecl *Fn = Cand->Function; 4942 4943 // Note deleted candidates, but only if they're viable. 4944 if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) { 4945 std::string FnDesc; 4946 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4947 4948 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) 4949 << FnKind << FnDesc << Fn->isDeleted(); 4950 return; 4951 } 4952 4953 // We don't really have anything else to say about viable candidates. 4954 if (Cand->Viable) { 4955 S.NoteOverloadCandidate(Fn); 4956 return; 4957 } 4958 4959 switch (Cand->FailureKind) { 4960 case ovl_fail_too_many_arguments: 4961 case ovl_fail_too_few_arguments: 4962 return DiagnoseArityMismatch(S, Cand, NumArgs); 4963 4964 case ovl_fail_bad_deduction: 4965 return DiagnoseBadDeduction(S, Cand, Args, NumArgs); 4966 4967 case ovl_fail_trivial_conversion: 4968 case ovl_fail_bad_final_conversion: 4969 case ovl_fail_final_conversion_not_exact: 4970 return S.NoteOverloadCandidate(Fn); 4971 4972 case ovl_fail_bad_conversion: { 4973 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); 4974 for (unsigned N = Cand->Conversions.size(); I != N; ++I) 4975 if (Cand->Conversions[I].isBad()) 4976 return DiagnoseBadConversion(S, Cand, I); 4977 4978 // FIXME: this currently happens when we're called from SemaInit 4979 // when user-conversion overload fails. Figure out how to handle 4980 // those conditions and diagnose them well. 4981 return S.NoteOverloadCandidate(Fn); 4982 } 4983 } 4984} 4985 4986void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 4987 // Desugar the type of the surrogate down to a function type, 4988 // retaining as many typedefs as possible while still showing 4989 // the function type (and, therefore, its parameter types). 4990 QualType FnType = Cand->Surrogate->getConversionType(); 4991 bool isLValueReference = false; 4992 bool isRValueReference = false; 4993 bool isPointer = false; 4994 if (const LValueReferenceType *FnTypeRef = 4995 FnType->getAs<LValueReferenceType>()) { 4996 FnType = FnTypeRef->getPointeeType(); 4997 isLValueReference = true; 4998 } else if (const RValueReferenceType *FnTypeRef = 4999 FnType->getAs<RValueReferenceType>()) { 5000 FnType = FnTypeRef->getPointeeType(); 5001 isRValueReference = true; 5002 } 5003 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 5004 FnType = FnTypePtr->getPointeeType(); 5005 isPointer = true; 5006 } 5007 // Desugar down to a function type. 5008 FnType = QualType(FnType->getAs<FunctionType>(), 0); 5009 // Reconstruct the pointer/reference as appropriate. 5010 if (isPointer) FnType = S.Context.getPointerType(FnType); 5011 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 5012 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 5013 5014 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 5015 << FnType; 5016} 5017 5018void NoteBuiltinOperatorCandidate(Sema &S, 5019 const char *Opc, 5020 SourceLocation OpLoc, 5021 OverloadCandidate *Cand) { 5022 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 5023 std::string TypeStr("operator"); 5024 TypeStr += Opc; 5025 TypeStr += "("; 5026 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 5027 if (Cand->Conversions.size() == 1) { 5028 TypeStr += ")"; 5029 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 5030 } else { 5031 TypeStr += ", "; 5032 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 5033 TypeStr += ")"; 5034 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 5035 } 5036} 5037 5038void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 5039 OverloadCandidate *Cand) { 5040 unsigned NoOperands = Cand->Conversions.size(); 5041 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 5042 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 5043 if (ICS.isBad()) break; // all meaningless after first invalid 5044 if (!ICS.isAmbiguous()) continue; 5045 5046 S.DiagnoseAmbiguousConversion(ICS, OpLoc, 5047 S.PDiag(diag::note_ambiguous_type_conversion)); 5048 } 5049} 5050 5051SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { 5052 if (Cand->Function) 5053 return Cand->Function->getLocation(); 5054 if (Cand->IsSurrogate) 5055 return Cand->Surrogate->getLocation(); 5056 return SourceLocation(); 5057} 5058 5059struct CompareOverloadCandidatesForDisplay { 5060 Sema &S; 5061 CompareOverloadCandidatesForDisplay(Sema &S) : S(S) {} 5062 5063 bool operator()(const OverloadCandidate *L, 5064 const OverloadCandidate *R) { 5065 // Fast-path this check. 5066 if (L == R) return false; 5067 5068 // Order first by viability. 5069 if (L->Viable) { 5070 if (!R->Viable) return true; 5071 5072 // TODO: introduce a tri-valued comparison for overload 5073 // candidates. Would be more worthwhile if we had a sort 5074 // that could exploit it. 5075 if (S.isBetterOverloadCandidate(*L, *R, SourceLocation())) return true; 5076 if (S.isBetterOverloadCandidate(*R, *L, SourceLocation())) return false; 5077 } else if (R->Viable) 5078 return false; 5079 5080 assert(L->Viable == R->Viable); 5081 5082 // Criteria by which we can sort non-viable candidates: 5083 if (!L->Viable) { 5084 // 1. Arity mismatches come after other candidates. 5085 if (L->FailureKind == ovl_fail_too_many_arguments || 5086 L->FailureKind == ovl_fail_too_few_arguments) 5087 return false; 5088 if (R->FailureKind == ovl_fail_too_many_arguments || 5089 R->FailureKind == ovl_fail_too_few_arguments) 5090 return true; 5091 5092 // 2. Bad conversions come first and are ordered by the number 5093 // of bad conversions and quality of good conversions. 5094 if (L->FailureKind == ovl_fail_bad_conversion) { 5095 if (R->FailureKind != ovl_fail_bad_conversion) 5096 return true; 5097 5098 // If there's any ordering between the defined conversions... 5099 // FIXME: this might not be transitive. 5100 assert(L->Conversions.size() == R->Conversions.size()); 5101 5102 int leftBetter = 0; 5103 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); 5104 for (unsigned E = L->Conversions.size(); I != E; ++I) { 5105 switch (S.CompareImplicitConversionSequences(L->Conversions[I], 5106 R->Conversions[I])) { 5107 case ImplicitConversionSequence::Better: 5108 leftBetter++; 5109 break; 5110 5111 case ImplicitConversionSequence::Worse: 5112 leftBetter--; 5113 break; 5114 5115 case ImplicitConversionSequence::Indistinguishable: 5116 break; 5117 } 5118 } 5119 if (leftBetter > 0) return true; 5120 if (leftBetter < 0) return false; 5121 5122 } else if (R->FailureKind == ovl_fail_bad_conversion) 5123 return false; 5124 5125 // TODO: others? 5126 } 5127 5128 // Sort everything else by location. 5129 SourceLocation LLoc = GetLocationForCandidate(L); 5130 SourceLocation RLoc = GetLocationForCandidate(R); 5131 5132 // Put candidates without locations (e.g. builtins) at the end. 5133 if (LLoc.isInvalid()) return false; 5134 if (RLoc.isInvalid()) return true; 5135 5136 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); 5137 } 5138}; 5139 5140/// CompleteNonViableCandidate - Normally, overload resolution only 5141/// computes up to the first 5142void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, 5143 Expr **Args, unsigned NumArgs) { 5144 assert(!Cand->Viable); 5145 5146 // Don't do anything on failures other than bad conversion. 5147 if (Cand->FailureKind != ovl_fail_bad_conversion) return; 5148 5149 // Skip forward to the first bad conversion. 5150 unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); 5151 unsigned ConvCount = Cand->Conversions.size(); 5152 while (true) { 5153 assert(ConvIdx != ConvCount && "no bad conversion in candidate"); 5154 ConvIdx++; 5155 if (Cand->Conversions[ConvIdx - 1].isBad()) 5156 break; 5157 } 5158 5159 if (ConvIdx == ConvCount) 5160 return; 5161 5162 assert(!Cand->Conversions[ConvIdx].isInitialized() && 5163 "remaining conversion is initialized?"); 5164 5165 // FIXME: this should probably be preserved from the overload 5166 // operation somehow. 5167 bool SuppressUserConversions = false; 5168 5169 const FunctionProtoType* Proto; 5170 unsigned ArgIdx = ConvIdx; 5171 5172 if (Cand->IsSurrogate) { 5173 QualType ConvType 5174 = Cand->Surrogate->getConversionType().getNonReferenceType(); 5175 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5176 ConvType = ConvPtrType->getPointeeType(); 5177 Proto = ConvType->getAs<FunctionProtoType>(); 5178 ArgIdx--; 5179 } else if (Cand->Function) { 5180 Proto = Cand->Function->getType()->getAs<FunctionProtoType>(); 5181 if (isa<CXXMethodDecl>(Cand->Function) && 5182 !isa<CXXConstructorDecl>(Cand->Function)) 5183 ArgIdx--; 5184 } else { 5185 // Builtin binary operator with a bad first conversion. 5186 assert(ConvCount <= 3); 5187 for (; ConvIdx != ConvCount; ++ConvIdx) 5188 Cand->Conversions[ConvIdx] 5189 = TryCopyInitialization(S, Args[ConvIdx], 5190 Cand->BuiltinTypes.ParamTypes[ConvIdx], 5191 SuppressUserConversions, 5192 /*InOverloadResolution*/ true); 5193 return; 5194 } 5195 5196 // Fill in the rest of the conversions. 5197 unsigned NumArgsInProto = Proto->getNumArgs(); 5198 for (; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { 5199 if (ArgIdx < NumArgsInProto) 5200 Cand->Conversions[ConvIdx] 5201 = TryCopyInitialization(S, Args[ArgIdx], Proto->getArgType(ArgIdx), 5202 SuppressUserConversions, 5203 /*InOverloadResolution=*/true); 5204 else 5205 Cand->Conversions[ConvIdx].setEllipsis(); 5206 } 5207} 5208 5209} // end anonymous namespace 5210 5211/// PrintOverloadCandidates - When overload resolution fails, prints 5212/// diagnostic messages containing the candidates in the candidate 5213/// set. 5214void 5215Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 5216 OverloadCandidateDisplayKind OCD, 5217 Expr **Args, unsigned NumArgs, 5218 const char *Opc, 5219 SourceLocation OpLoc) { 5220 // Sort the candidates by viability and position. Sorting directly would 5221 // be prohibitive, so we make a set of pointers and sort those. 5222 llvm::SmallVector<OverloadCandidate*, 32> Cands; 5223 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 5224 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 5225 LastCand = CandidateSet.end(); 5226 Cand != LastCand; ++Cand) { 5227 if (Cand->Viable) 5228 Cands.push_back(Cand); 5229 else if (OCD == OCD_AllCandidates) { 5230 CompleteNonViableCandidate(*this, Cand, Args, NumArgs); 5231 Cands.push_back(Cand); 5232 } 5233 } 5234 5235 std::sort(Cands.begin(), Cands.end(), 5236 CompareOverloadCandidatesForDisplay(*this)); 5237 5238 bool ReportedAmbiguousConversions = false; 5239 5240 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 5241 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 5242 OverloadCandidate *Cand = *I; 5243 5244 if (Cand->Function) 5245 NoteFunctionCandidate(*this, Cand, Args, NumArgs); 5246 else if (Cand->IsSurrogate) 5247 NoteSurrogateCandidate(*this, Cand); 5248 5249 // This a builtin candidate. We do not, in general, want to list 5250 // every possible builtin candidate. 5251 else if (Cand->Viable) { 5252 // Generally we only see ambiguities including viable builtin 5253 // operators if overload resolution got screwed up by an 5254 // ambiguous user-defined conversion. 5255 // 5256 // FIXME: It's quite possible for different conversions to see 5257 // different ambiguities, though. 5258 if (!ReportedAmbiguousConversions) { 5259 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 5260 ReportedAmbiguousConversions = true; 5261 } 5262 5263 // If this is a viable builtin, print it. 5264 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 5265 } 5266 } 5267} 5268 5269static bool CheckUnresolvedAccess(Sema &S, OverloadExpr *E, DeclAccessPair D) { 5270 if (isa<UnresolvedLookupExpr>(E)) 5271 return S.CheckUnresolvedLookupAccess(cast<UnresolvedLookupExpr>(E), D); 5272 5273 return S.CheckUnresolvedMemberAccess(cast<UnresolvedMemberExpr>(E), D); 5274} 5275 5276/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 5277/// an overloaded function (C++ [over.over]), where @p From is an 5278/// expression with overloaded function type and @p ToType is the type 5279/// we're trying to resolve to. For example: 5280/// 5281/// @code 5282/// int f(double); 5283/// int f(int); 5284/// 5285/// int (*pfd)(double) = f; // selects f(double) 5286/// @endcode 5287/// 5288/// This routine returns the resulting FunctionDecl if it could be 5289/// resolved, and NULL otherwise. When @p Complain is true, this 5290/// routine will emit diagnostics if there is an error. 5291FunctionDecl * 5292Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 5293 bool Complain, 5294 DeclAccessPair &FoundResult) { 5295 QualType FunctionType = ToType; 5296 bool IsMember = false; 5297 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 5298 FunctionType = ToTypePtr->getPointeeType(); 5299 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 5300 FunctionType = ToTypeRef->getPointeeType(); 5301 else if (const MemberPointerType *MemTypePtr = 5302 ToType->getAs<MemberPointerType>()) { 5303 FunctionType = MemTypePtr->getPointeeType(); 5304 IsMember = true; 5305 } 5306 5307 // C++ [over.over]p1: 5308 // [...] [Note: any redundant set of parentheses surrounding the 5309 // overloaded function name is ignored (5.1). ] 5310 // C++ [over.over]p1: 5311 // [...] The overloaded function name can be preceded by the & 5312 // operator. 5313 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5314 TemplateArgumentListInfo ETABuffer, *ExplicitTemplateArgs = 0; 5315 if (OvlExpr->hasExplicitTemplateArgs()) { 5316 OvlExpr->getExplicitTemplateArgs().copyInto(ETABuffer); 5317 ExplicitTemplateArgs = &ETABuffer; 5318 } 5319 5320 // We expect a pointer or reference to function, or a function pointer. 5321 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 5322 if (!FunctionType->isFunctionType()) { 5323 if (Complain) 5324 Diag(From->getLocStart(), diag::err_addr_ovl_not_func_ptrref) 5325 << OvlExpr->getName() << ToType; 5326 5327 return 0; 5328 } 5329 5330 assert(From->getType() == Context.OverloadTy); 5331 5332 // Look through all of the overloaded functions, searching for one 5333 // whose type matches exactly. 5334 llvm::SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; 5335 llvm::SmallVector<FunctionDecl *, 4> NonMatches; 5336 5337 bool FoundNonTemplateFunction = false; 5338 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5339 E = OvlExpr->decls_end(); I != E; ++I) { 5340 // Look through any using declarations to find the underlying function. 5341 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 5342 5343 // C++ [over.over]p3: 5344 // Non-member functions and static member functions match 5345 // targets of type "pointer-to-function" or "reference-to-function." 5346 // Nonstatic member functions match targets of 5347 // type "pointer-to-member-function." 5348 // Note that according to DR 247, the containing class does not matter. 5349 5350 if (FunctionTemplateDecl *FunctionTemplate 5351 = dyn_cast<FunctionTemplateDecl>(Fn)) { 5352 if (CXXMethodDecl *Method 5353 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 5354 // Skip non-static function templates when converting to pointer, and 5355 // static when converting to member pointer. 5356 if (Method->isStatic() == IsMember) 5357 continue; 5358 } else if (IsMember) 5359 continue; 5360 5361 // C++ [over.over]p2: 5362 // If the name is a function template, template argument deduction is 5363 // done (14.8.2.2), and if the argument deduction succeeds, the 5364 // resulting template argument list is used to generate a single 5365 // function template specialization, which is added to the set of 5366 // overloaded functions considered. 5367 // FIXME: We don't really want to build the specialization here, do we? 5368 FunctionDecl *Specialization = 0; 5369 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5370 if (TemplateDeductionResult Result 5371 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 5372 FunctionType, Specialization, Info)) { 5373 // FIXME: make a note of the failed deduction for diagnostics. 5374 (void)Result; 5375 } else { 5376 // FIXME: If the match isn't exact, shouldn't we just drop this as 5377 // a candidate? Find a testcase before changing the code. 5378 assert(FunctionType 5379 == Context.getCanonicalType(Specialization->getType())); 5380 Matches.push_back(std::make_pair(I.getPair(), 5381 cast<FunctionDecl>(Specialization->getCanonicalDecl()))); 5382 } 5383 5384 continue; 5385 } 5386 5387 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 5388 // Skip non-static functions when converting to pointer, and static 5389 // when converting to member pointer. 5390 if (Method->isStatic() == IsMember) 5391 continue; 5392 5393 // If we have explicit template arguments, skip non-templates. 5394 if (OvlExpr->hasExplicitTemplateArgs()) 5395 continue; 5396 } else if (IsMember) 5397 continue; 5398 5399 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 5400 QualType ResultTy; 5401 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 5402 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 5403 ResultTy)) { 5404 Matches.push_back(std::make_pair(I.getPair(), 5405 cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); 5406 FoundNonTemplateFunction = true; 5407 } 5408 } 5409 } 5410 5411 // If there were 0 or 1 matches, we're done. 5412 if (Matches.empty()) { 5413 if (Complain) { 5414 Diag(From->getLocStart(), diag::err_addr_ovl_no_viable) 5415 << OvlExpr->getName() << FunctionType; 5416 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5417 E = OvlExpr->decls_end(); 5418 I != E; ++I) 5419 if (FunctionDecl *F = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) 5420 NoteOverloadCandidate(F); 5421 } 5422 5423 return 0; 5424 } else if (Matches.size() == 1) { 5425 FunctionDecl *Result = Matches[0].second; 5426 FoundResult = Matches[0].first; 5427 MarkDeclarationReferenced(From->getLocStart(), Result); 5428 if (Complain) 5429 CheckAddressOfMemberAccess(OvlExpr, Matches[0].first); 5430 return Result; 5431 } 5432 5433 // C++ [over.over]p4: 5434 // If more than one function is selected, [...] 5435 if (!FoundNonTemplateFunction) { 5436 // [...] and any given function template specialization F1 is 5437 // eliminated if the set contains a second function template 5438 // specialization whose function template is more specialized 5439 // than the function template of F1 according to the partial 5440 // ordering rules of 14.5.5.2. 5441 5442 // The algorithm specified above is quadratic. We instead use a 5443 // two-pass algorithm (similar to the one used to identify the 5444 // best viable function in an overload set) that identifies the 5445 // best function template (if it exists). 5446 5447 UnresolvedSet<4> MatchesCopy; // TODO: avoid! 5448 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5449 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); 5450 5451 UnresolvedSetIterator Result = 5452 getMostSpecialized(MatchesCopy.begin(), MatchesCopy.end(), 5453 TPOC_Other, From->getLocStart(), 5454 PDiag(), 5455 PDiag(diag::err_addr_ovl_ambiguous) 5456 << Matches[0].second->getDeclName(), 5457 PDiag(diag::note_ovl_candidate) 5458 << (unsigned) oc_function_template); 5459 assert(Result != MatchesCopy.end() && "no most-specialized template"); 5460 MarkDeclarationReferenced(From->getLocStart(), *Result); 5461 FoundResult = Matches[Result - MatchesCopy.begin()].first; 5462 if (Complain) 5463 CheckUnresolvedAccess(*this, OvlExpr, FoundResult); 5464 return cast<FunctionDecl>(*Result); 5465 } 5466 5467 // [...] any function template specializations in the set are 5468 // eliminated if the set also contains a non-template function, [...] 5469 for (unsigned I = 0, N = Matches.size(); I != N; ) { 5470 if (Matches[I].second->getPrimaryTemplate() == 0) 5471 ++I; 5472 else { 5473 Matches[I] = Matches[--N]; 5474 Matches.set_size(N); 5475 } 5476 } 5477 5478 // [...] After such eliminations, if any, there shall remain exactly one 5479 // selected function. 5480 if (Matches.size() == 1) { 5481 MarkDeclarationReferenced(From->getLocStart(), Matches[0].second); 5482 FoundResult = Matches[0].first; 5483 if (Complain) 5484 CheckUnresolvedAccess(*this, OvlExpr, Matches[0].first); 5485 return cast<FunctionDecl>(Matches[0].second); 5486 } 5487 5488 // FIXME: We should probably return the same thing that BestViableFunction 5489 // returns (even if we issue the diagnostics here). 5490 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 5491 << Matches[0].second->getDeclName(); 5492 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5493 NoteOverloadCandidate(Matches[I].second); 5494 return 0; 5495} 5496 5497/// \brief Given an expression that refers to an overloaded function, try to 5498/// resolve that overloaded function expression down to a single function. 5499/// 5500/// This routine can only resolve template-ids that refer to a single function 5501/// template, where that template-id refers to a single template whose template 5502/// arguments are either provided by the template-id or have defaults, 5503/// as described in C++0x [temp.arg.explicit]p3. 5504FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 5505 // C++ [over.over]p1: 5506 // [...] [Note: any redundant set of parentheses surrounding the 5507 // overloaded function name is ignored (5.1). ] 5508 // C++ [over.over]p1: 5509 // [...] The overloaded function name can be preceded by the & 5510 // operator. 5511 5512 if (From->getType() != Context.OverloadTy) 5513 return 0; 5514 5515 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5516 5517 // If we didn't actually find any template-ids, we're done. 5518 if (!OvlExpr->hasExplicitTemplateArgs()) 5519 return 0; 5520 5521 TemplateArgumentListInfo ExplicitTemplateArgs; 5522 OvlExpr->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 5523 5524 // Look through all of the overloaded functions, searching for one 5525 // whose type matches exactly. 5526 FunctionDecl *Matched = 0; 5527 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5528 E = OvlExpr->decls_end(); I != E; ++I) { 5529 // C++0x [temp.arg.explicit]p3: 5530 // [...] In contexts where deduction is done and fails, or in contexts 5531 // where deduction is not done, if a template argument list is 5532 // specified and it, along with any default template arguments, 5533 // identifies a single function template specialization, then the 5534 // template-id is an lvalue for the function template specialization. 5535 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 5536 5537 // C++ [over.over]p2: 5538 // If the name is a function template, template argument deduction is 5539 // done (14.8.2.2), and if the argument deduction succeeds, the 5540 // resulting template argument list is used to generate a single 5541 // function template specialization, which is added to the set of 5542 // overloaded functions considered. 5543 FunctionDecl *Specialization = 0; 5544 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5545 if (TemplateDeductionResult Result 5546 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 5547 Specialization, Info)) { 5548 // FIXME: make a note of the failed deduction for diagnostics. 5549 (void)Result; 5550 continue; 5551 } 5552 5553 // Multiple matches; we can't resolve to a single declaration. 5554 if (Matched) 5555 return 0; 5556 5557 Matched = Specialization; 5558 } 5559 5560 return Matched; 5561} 5562 5563/// \brief Add a single candidate to the overload set. 5564static void AddOverloadedCallCandidate(Sema &S, 5565 DeclAccessPair FoundDecl, 5566 const TemplateArgumentListInfo *ExplicitTemplateArgs, 5567 Expr **Args, unsigned NumArgs, 5568 OverloadCandidateSet &CandidateSet, 5569 bool PartialOverloading) { 5570 NamedDecl *Callee = FoundDecl.getDecl(); 5571 if (isa<UsingShadowDecl>(Callee)) 5572 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 5573 5574 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 5575 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 5576 S.AddOverloadCandidate(Func, FoundDecl, Args, NumArgs, CandidateSet, 5577 false, PartialOverloading); 5578 return; 5579 } 5580 5581 if (FunctionTemplateDecl *FuncTemplate 5582 = dyn_cast<FunctionTemplateDecl>(Callee)) { 5583 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, 5584 ExplicitTemplateArgs, 5585 Args, NumArgs, CandidateSet); 5586 return; 5587 } 5588 5589 assert(false && "unhandled case in overloaded call candidate"); 5590 5591 // do nothing? 5592} 5593 5594/// \brief Add the overload candidates named by callee and/or found by argument 5595/// dependent lookup to the given overload set. 5596void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 5597 Expr **Args, unsigned NumArgs, 5598 OverloadCandidateSet &CandidateSet, 5599 bool PartialOverloading) { 5600 5601#ifndef NDEBUG 5602 // Verify that ArgumentDependentLookup is consistent with the rules 5603 // in C++0x [basic.lookup.argdep]p3: 5604 // 5605 // Let X be the lookup set produced by unqualified lookup (3.4.1) 5606 // and let Y be the lookup set produced by argument dependent 5607 // lookup (defined as follows). If X contains 5608 // 5609 // -- a declaration of a class member, or 5610 // 5611 // -- a block-scope function declaration that is not a 5612 // using-declaration, or 5613 // 5614 // -- a declaration that is neither a function or a function 5615 // template 5616 // 5617 // then Y is empty. 5618 5619 if (ULE->requiresADL()) { 5620 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5621 E = ULE->decls_end(); I != E; ++I) { 5622 assert(!(*I)->getDeclContext()->isRecord()); 5623 assert(isa<UsingShadowDecl>(*I) || 5624 !(*I)->getDeclContext()->isFunctionOrMethod()); 5625 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 5626 } 5627 } 5628#endif 5629 5630 // It would be nice to avoid this copy. 5631 TemplateArgumentListInfo TABuffer; 5632 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5633 if (ULE->hasExplicitTemplateArgs()) { 5634 ULE->copyTemplateArgumentsInto(TABuffer); 5635 ExplicitTemplateArgs = &TABuffer; 5636 } 5637 5638 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5639 E = ULE->decls_end(); I != E; ++I) 5640 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, 5641 Args, NumArgs, CandidateSet, 5642 PartialOverloading); 5643 5644 if (ULE->requiresADL()) 5645 AddArgumentDependentLookupCandidates(ULE->getName(), /*Operator*/ false, 5646 Args, NumArgs, 5647 ExplicitTemplateArgs, 5648 CandidateSet, 5649 PartialOverloading); 5650} 5651 5652static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 5653 Expr **Args, unsigned NumArgs) { 5654 Fn->Destroy(SemaRef.Context); 5655 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5656 Args[Arg]->Destroy(SemaRef.Context); 5657 return SemaRef.ExprError(); 5658} 5659 5660/// Attempts to recover from a call where no functions were found. 5661/// 5662/// Returns true if new candidates were found. 5663static Sema::OwningExprResult 5664BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, 5665 UnresolvedLookupExpr *ULE, 5666 SourceLocation LParenLoc, 5667 Expr **Args, unsigned NumArgs, 5668 SourceLocation *CommaLocs, 5669 SourceLocation RParenLoc) { 5670 5671 CXXScopeSpec SS; 5672 if (ULE->getQualifier()) { 5673 SS.setScopeRep(ULE->getQualifier()); 5674 SS.setRange(ULE->getQualifierRange()); 5675 } 5676 5677 TemplateArgumentListInfo TABuffer; 5678 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5679 if (ULE->hasExplicitTemplateArgs()) { 5680 ULE->copyTemplateArgumentsInto(TABuffer); 5681 ExplicitTemplateArgs = &TABuffer; 5682 } 5683 5684 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 5685 Sema::LookupOrdinaryName); 5686 if (SemaRef.DiagnoseEmptyLookup(S, SS, R)) 5687 return Destroy(SemaRef, Fn, Args, NumArgs); 5688 5689 assert(!R.empty() && "lookup results empty despite recovery"); 5690 5691 // Build an implicit member call if appropriate. Just drop the 5692 // casts and such from the call, we don't really care. 5693 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 5694 if ((*R.begin())->isCXXClassMember()) 5695 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 5696 else if (ExplicitTemplateArgs) 5697 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 5698 else 5699 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 5700 5701 if (NewFn.isInvalid()) 5702 return Destroy(SemaRef, Fn, Args, NumArgs); 5703 5704 Fn->Destroy(SemaRef.Context); 5705 5706 // This shouldn't cause an infinite loop because we're giving it 5707 // an expression with non-empty lookup results, which should never 5708 // end up here. 5709 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 5710 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 5711 CommaLocs, RParenLoc); 5712} 5713 5714/// ResolveOverloadedCallFn - Given the call expression that calls Fn 5715/// (which eventually refers to the declaration Func) and the call 5716/// arguments Args/NumArgs, attempt to resolve the function call down 5717/// to a specific function. If overload resolution succeeds, returns 5718/// the function declaration produced by overload 5719/// resolution. Otherwise, emits diagnostics, deletes all of the 5720/// arguments and Fn, and returns NULL. 5721Sema::OwningExprResult 5722Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, 5723 SourceLocation LParenLoc, 5724 Expr **Args, unsigned NumArgs, 5725 SourceLocation *CommaLocs, 5726 SourceLocation RParenLoc) { 5727#ifndef NDEBUG 5728 if (ULE->requiresADL()) { 5729 // To do ADL, we must have found an unqualified name. 5730 assert(!ULE->getQualifier() && "qualified name with ADL"); 5731 5732 // We don't perform ADL for implicit declarations of builtins. 5733 // Verify that this was correctly set up. 5734 FunctionDecl *F; 5735 if (ULE->decls_begin() + 1 == ULE->decls_end() && 5736 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 5737 F->getBuiltinID() && F->isImplicit()) 5738 assert(0 && "performing ADL for builtin"); 5739 5740 // We don't perform ADL in C. 5741 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 5742 } 5743#endif 5744 5745 OverloadCandidateSet CandidateSet(Fn->getExprLoc()); 5746 5747 // Add the functions denoted by the callee to the set of candidate 5748 // functions, including those from argument-dependent lookup. 5749 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 5750 5751 // If we found nothing, try to recover. 5752 // AddRecoveryCallCandidates diagnoses the error itself, so we just 5753 // bailout out if it fails. 5754 if (CandidateSet.empty()) 5755 return BuildRecoveryCallExpr(*this, S, Fn, ULE, LParenLoc, Args, NumArgs, 5756 CommaLocs, RParenLoc); 5757 5758 OverloadCandidateSet::iterator Best; 5759 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 5760 case OR_Success: { 5761 FunctionDecl *FDecl = Best->Function; 5762 CheckUnresolvedLookupAccess(ULE, Best->FoundDecl); 5763 Fn = FixOverloadedFunctionReference(Fn, Best->FoundDecl, FDecl); 5764 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 5765 } 5766 5767 case OR_No_Viable_Function: 5768 Diag(Fn->getSourceRange().getBegin(), 5769 diag::err_ovl_no_viable_function_in_call) 5770 << ULE->getName() << Fn->getSourceRange(); 5771 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5772 break; 5773 5774 case OR_Ambiguous: 5775 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 5776 << ULE->getName() << Fn->getSourceRange(); 5777 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 5778 break; 5779 5780 case OR_Deleted: 5781 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 5782 << Best->Function->isDeleted() 5783 << ULE->getName() 5784 << Fn->getSourceRange(); 5785 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5786 break; 5787 } 5788 5789 // Overload resolution failed. Destroy all of the subexpressions and 5790 // return NULL. 5791 Fn->Destroy(Context); 5792 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5793 Args[Arg]->Destroy(Context); 5794 return ExprError(); 5795} 5796 5797static bool IsOverloaded(const UnresolvedSetImpl &Functions) { 5798 return Functions.size() > 1 || 5799 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 5800} 5801 5802/// \brief Create a unary operation that may resolve to an overloaded 5803/// operator. 5804/// 5805/// \param OpLoc The location of the operator itself (e.g., '*'). 5806/// 5807/// \param OpcIn The UnaryOperator::Opcode that describes this 5808/// operator. 5809/// 5810/// \param Functions The set of non-member functions that will be 5811/// considered by overload resolution. The caller needs to build this 5812/// set based on the context using, e.g., 5813/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5814/// set should not contain any member functions; those will be added 5815/// by CreateOverloadedUnaryOp(). 5816/// 5817/// \param input The input argument. 5818Sema::OwningExprResult 5819Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn, 5820 const UnresolvedSetImpl &Fns, 5821 ExprArg input) { 5822 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 5823 Expr *Input = (Expr *)input.get(); 5824 5825 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 5826 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 5827 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5828 5829 Expr *Args[2] = { Input, 0 }; 5830 unsigned NumArgs = 1; 5831 5832 // For post-increment and post-decrement, add the implicit '0' as 5833 // the second argument, so that we know this is a post-increment or 5834 // post-decrement. 5835 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 5836 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 5837 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 5838 SourceLocation()); 5839 NumArgs = 2; 5840 } 5841 5842 if (Input->isTypeDependent()) { 5843 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 5844 UnresolvedLookupExpr *Fn 5845 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 5846 0, SourceRange(), OpName, OpLoc, 5847 /*ADL*/ true, IsOverloaded(Fns)); 5848 Fn->addDecls(Fns.begin(), Fns.end()); 5849 5850 input.release(); 5851 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 5852 &Args[0], NumArgs, 5853 Context.DependentTy, 5854 OpLoc)); 5855 } 5856 5857 // Build an empty overload set. 5858 OverloadCandidateSet CandidateSet(OpLoc); 5859 5860 // Add the candidates from the given function set. 5861 AddFunctionCandidates(Fns, &Args[0], NumArgs, CandidateSet, false); 5862 5863 // Add operator candidates that are member functions. 5864 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5865 5866 // Add candidates from ADL. 5867 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 5868 Args, NumArgs, 5869 /*ExplicitTemplateArgs*/ 0, 5870 CandidateSet); 5871 5872 // Add builtin operator candidates. 5873 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5874 5875 // Perform overload resolution. 5876 OverloadCandidateSet::iterator Best; 5877 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5878 case OR_Success: { 5879 // We found a built-in operator or an overloaded operator. 5880 FunctionDecl *FnDecl = Best->Function; 5881 5882 if (FnDecl) { 5883 // We matched an overloaded operator. Build a call to that 5884 // operator. 5885 5886 // Convert the arguments. 5887 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 5888 CheckMemberOperatorAccess(OpLoc, Args[0], 0, Best->FoundDecl); 5889 5890 if (PerformObjectArgumentInitialization(Input, /*Qualifier=*/0, 5891 Best->FoundDecl, Method)) 5892 return ExprError(); 5893 } else { 5894 // Convert the arguments. 5895 OwningExprResult InputInit 5896 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 5897 FnDecl->getParamDecl(0)), 5898 SourceLocation(), 5899 move(input)); 5900 if (InputInit.isInvalid()) 5901 return ExprError(); 5902 5903 input = move(InputInit); 5904 Input = (Expr *)input.get(); 5905 } 5906 5907 // Determine the result type 5908 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 5909 5910 // Build the actual expression node. 5911 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5912 SourceLocation()); 5913 UsualUnaryConversions(FnExpr); 5914 5915 input.release(); 5916 Args[0] = Input; 5917 ExprOwningPtr<CallExpr> TheCall(this, 5918 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 5919 Args, NumArgs, ResultTy, OpLoc)); 5920 5921 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 5922 FnDecl)) 5923 return ExprError(); 5924 5925 return MaybeBindToTemporary(TheCall.release()); 5926 } else { 5927 // We matched a built-in operator. Convert the arguments, then 5928 // break out so that we will build the appropriate built-in 5929 // operator node. 5930 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 5931 Best->Conversions[0], AA_Passing)) 5932 return ExprError(); 5933 5934 break; 5935 } 5936 } 5937 5938 case OR_No_Viable_Function: 5939 // No viable function; fall through to handling this as a 5940 // built-in operator, which will produce an error message for us. 5941 break; 5942 5943 case OR_Ambiguous: 5944 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5945 << UnaryOperator::getOpcodeStr(Opc) 5946 << Input->getSourceRange(); 5947 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs, 5948 UnaryOperator::getOpcodeStr(Opc), OpLoc); 5949 return ExprError(); 5950 5951 case OR_Deleted: 5952 Diag(OpLoc, diag::err_ovl_deleted_oper) 5953 << Best->Function->isDeleted() 5954 << UnaryOperator::getOpcodeStr(Opc) 5955 << Input->getSourceRange(); 5956 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5957 return ExprError(); 5958 } 5959 5960 // Either we found no viable overloaded operator or we matched a 5961 // built-in operator. In either case, fall through to trying to 5962 // build a built-in operation. 5963 input.release(); 5964 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 5965} 5966 5967/// \brief Create a binary operation that may resolve to an overloaded 5968/// operator. 5969/// 5970/// \param OpLoc The location of the operator itself (e.g., '+'). 5971/// 5972/// \param OpcIn The BinaryOperator::Opcode that describes this 5973/// operator. 5974/// 5975/// \param Functions The set of non-member functions that will be 5976/// considered by overload resolution. The caller needs to build this 5977/// set based on the context using, e.g., 5978/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5979/// set should not contain any member functions; those will be added 5980/// by CreateOverloadedBinOp(). 5981/// 5982/// \param LHS Left-hand argument. 5983/// \param RHS Right-hand argument. 5984Sema::OwningExprResult 5985Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 5986 unsigned OpcIn, 5987 const UnresolvedSetImpl &Fns, 5988 Expr *LHS, Expr *RHS) { 5989 Expr *Args[2] = { LHS, RHS }; 5990 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 5991 5992 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 5993 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 5994 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5995 5996 // If either side is type-dependent, create an appropriate dependent 5997 // expression. 5998 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 5999 if (Fns.empty()) { 6000 // If there are no functions to store, just build a dependent 6001 // BinaryOperator or CompoundAssignment. 6002 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 6003 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 6004 Context.DependentTy, OpLoc)); 6005 6006 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 6007 Context.DependentTy, 6008 Context.DependentTy, 6009 Context.DependentTy, 6010 OpLoc)); 6011 } 6012 6013 // FIXME: save results of ADL from here? 6014 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6015 UnresolvedLookupExpr *Fn 6016 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6017 0, SourceRange(), OpName, OpLoc, 6018 /*ADL*/ true, IsOverloaded(Fns)); 6019 6020 Fn->addDecls(Fns.begin(), Fns.end()); 6021 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6022 Args, 2, 6023 Context.DependentTy, 6024 OpLoc)); 6025 } 6026 6027 // If this is the .* operator, which is not overloadable, just 6028 // create a built-in binary operator. 6029 if (Opc == BinaryOperator::PtrMemD) 6030 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6031 6032 // If this is the assignment operator, we only perform overload resolution 6033 // if the left-hand side is a class or enumeration type. This is actually 6034 // a hack. The standard requires that we do overload resolution between the 6035 // various built-in candidates, but as DR507 points out, this can lead to 6036 // problems. So we do it this way, which pretty much follows what GCC does. 6037 // Note that we go the traditional code path for compound assignment forms. 6038 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 6039 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6040 6041 // Build an empty overload set. 6042 OverloadCandidateSet CandidateSet(OpLoc); 6043 6044 // Add the candidates from the given function set. 6045 AddFunctionCandidates(Fns, Args, 2, CandidateSet, false); 6046 6047 // Add operator candidates that are member functions. 6048 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6049 6050 // Add candidates from ADL. 6051 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6052 Args, 2, 6053 /*ExplicitTemplateArgs*/ 0, 6054 CandidateSet); 6055 6056 // Add builtin operator candidates. 6057 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6058 6059 // Perform overload resolution. 6060 OverloadCandidateSet::iterator Best; 6061 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6062 case OR_Success: { 6063 // We found a built-in operator or an overloaded operator. 6064 FunctionDecl *FnDecl = Best->Function; 6065 6066 if (FnDecl) { 6067 // We matched an overloaded operator. Build a call to that 6068 // operator. 6069 6070 // Convert the arguments. 6071 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6072 // Best->Access is only meaningful for class members. 6073 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); 6074 6075 OwningExprResult Arg1 6076 = PerformCopyInitialization( 6077 InitializedEntity::InitializeParameter( 6078 FnDecl->getParamDecl(0)), 6079 SourceLocation(), 6080 Owned(Args[1])); 6081 if (Arg1.isInvalid()) 6082 return ExprError(); 6083 6084 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6085 Best->FoundDecl, Method)) 6086 return ExprError(); 6087 6088 Args[1] = RHS = Arg1.takeAs<Expr>(); 6089 } else { 6090 // Convert the arguments. 6091 OwningExprResult Arg0 6092 = PerformCopyInitialization( 6093 InitializedEntity::InitializeParameter( 6094 FnDecl->getParamDecl(0)), 6095 SourceLocation(), 6096 Owned(Args[0])); 6097 if (Arg0.isInvalid()) 6098 return ExprError(); 6099 6100 OwningExprResult Arg1 6101 = PerformCopyInitialization( 6102 InitializedEntity::InitializeParameter( 6103 FnDecl->getParamDecl(1)), 6104 SourceLocation(), 6105 Owned(Args[1])); 6106 if (Arg1.isInvalid()) 6107 return ExprError(); 6108 Args[0] = LHS = Arg0.takeAs<Expr>(); 6109 Args[1] = RHS = Arg1.takeAs<Expr>(); 6110 } 6111 6112 // Determine the result type 6113 QualType ResultTy 6114 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6115 ResultTy = ResultTy.getNonReferenceType(); 6116 6117 // Build the actual expression node. 6118 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6119 OpLoc); 6120 UsualUnaryConversions(FnExpr); 6121 6122 ExprOwningPtr<CXXOperatorCallExpr> 6123 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6124 Args, 2, ResultTy, 6125 OpLoc)); 6126 6127 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6128 FnDecl)) 6129 return ExprError(); 6130 6131 return MaybeBindToTemporary(TheCall.release()); 6132 } else { 6133 // We matched a built-in operator. Convert the arguments, then 6134 // break out so that we will build the appropriate built-in 6135 // operator node. 6136 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6137 Best->Conversions[0], AA_Passing) || 6138 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6139 Best->Conversions[1], AA_Passing)) 6140 return ExprError(); 6141 6142 break; 6143 } 6144 } 6145 6146 case OR_No_Viable_Function: { 6147 // C++ [over.match.oper]p9: 6148 // If the operator is the operator , [...] and there are no 6149 // viable functions, then the operator is assumed to be the 6150 // built-in operator and interpreted according to clause 5. 6151 if (Opc == BinaryOperator::Comma) 6152 break; 6153 6154 // For class as left operand for assignment or compound assigment operator 6155 // do not fall through to handling in built-in, but report that no overloaded 6156 // assignment operator found 6157 OwningExprResult Result = ExprError(); 6158 if (Args[0]->getType()->isRecordType() && 6159 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 6160 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6161 << BinaryOperator::getOpcodeStr(Opc) 6162 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6163 } else { 6164 // No viable function; try to create a built-in operation, which will 6165 // produce an error. Then, show the non-viable candidates. 6166 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6167 } 6168 assert(Result.isInvalid() && 6169 "C++ binary operator overloading is missing candidates!"); 6170 if (Result.isInvalid()) 6171 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6172 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6173 return move(Result); 6174 } 6175 6176 case OR_Ambiguous: 6177 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6178 << BinaryOperator::getOpcodeStr(Opc) 6179 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6180 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6181 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6182 return ExprError(); 6183 6184 case OR_Deleted: 6185 Diag(OpLoc, diag::err_ovl_deleted_oper) 6186 << Best->Function->isDeleted() 6187 << BinaryOperator::getOpcodeStr(Opc) 6188 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6189 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2); 6190 return ExprError(); 6191 } 6192 6193 // We matched a built-in operator; build it. 6194 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6195} 6196 6197Action::OwningExprResult 6198Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 6199 SourceLocation RLoc, 6200 ExprArg Base, ExprArg Idx) { 6201 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 6202 static_cast<Expr*>(Idx.get()) }; 6203 DeclarationName OpName = 6204 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 6205 6206 // If either side is type-dependent, create an appropriate dependent 6207 // expression. 6208 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6209 6210 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6211 UnresolvedLookupExpr *Fn 6212 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6213 0, SourceRange(), OpName, LLoc, 6214 /*ADL*/ true, /*Overloaded*/ false); 6215 // Can't add any actual overloads yet 6216 6217 Base.release(); 6218 Idx.release(); 6219 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 6220 Args, 2, 6221 Context.DependentTy, 6222 RLoc)); 6223 } 6224 6225 // Build an empty overload set. 6226 OverloadCandidateSet CandidateSet(LLoc); 6227 6228 // Subscript can only be overloaded as a member function. 6229 6230 // Add operator candidates that are member functions. 6231 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6232 6233 // Add builtin operator candidates. 6234 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6235 6236 // Perform overload resolution. 6237 OverloadCandidateSet::iterator Best; 6238 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 6239 case OR_Success: { 6240 // We found a built-in operator or an overloaded operator. 6241 FunctionDecl *FnDecl = Best->Function; 6242 6243 if (FnDecl) { 6244 // We matched an overloaded operator. Build a call to that 6245 // operator. 6246 6247 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); 6248 6249 // Convert the arguments. 6250 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 6251 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6252 Best->FoundDecl, Method)) 6253 return ExprError(); 6254 6255 // Convert the arguments. 6256 OwningExprResult InputInit 6257 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6258 FnDecl->getParamDecl(0)), 6259 SourceLocation(), 6260 Owned(Args[1])); 6261 if (InputInit.isInvalid()) 6262 return ExprError(); 6263 6264 Args[1] = InputInit.takeAs<Expr>(); 6265 6266 // Determine the result type 6267 QualType ResultTy 6268 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6269 ResultTy = ResultTy.getNonReferenceType(); 6270 6271 // Build the actual expression node. 6272 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6273 LLoc); 6274 UsualUnaryConversions(FnExpr); 6275 6276 Base.release(); 6277 Idx.release(); 6278 ExprOwningPtr<CXXOperatorCallExpr> 6279 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 6280 FnExpr, Args, 2, 6281 ResultTy, RLoc)); 6282 6283 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 6284 FnDecl)) 6285 return ExprError(); 6286 6287 return MaybeBindToTemporary(TheCall.release()); 6288 } else { 6289 // We matched a built-in operator. Convert the arguments, then 6290 // break out so that we will build the appropriate built-in 6291 // operator node. 6292 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6293 Best->Conversions[0], AA_Passing) || 6294 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6295 Best->Conversions[1], AA_Passing)) 6296 return ExprError(); 6297 6298 break; 6299 } 6300 } 6301 6302 case OR_No_Viable_Function: { 6303 if (CandidateSet.empty()) 6304 Diag(LLoc, diag::err_ovl_no_oper) 6305 << Args[0]->getType() << /*subscript*/ 0 6306 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6307 else 6308 Diag(LLoc, diag::err_ovl_no_viable_subscript) 6309 << Args[0]->getType() 6310 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6311 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6312 "[]", LLoc); 6313 return ExprError(); 6314 } 6315 6316 case OR_Ambiguous: 6317 Diag(LLoc, diag::err_ovl_ambiguous_oper) 6318 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6319 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6320 "[]", LLoc); 6321 return ExprError(); 6322 6323 case OR_Deleted: 6324 Diag(LLoc, diag::err_ovl_deleted_oper) 6325 << Best->Function->isDeleted() << "[]" 6326 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6327 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6328 "[]", LLoc); 6329 return ExprError(); 6330 } 6331 6332 // We matched a built-in operator; build it. 6333 Base.release(); 6334 Idx.release(); 6335 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 6336 Owned(Args[1]), RLoc); 6337} 6338 6339/// BuildCallToMemberFunction - Build a call to a member 6340/// function. MemExpr is the expression that refers to the member 6341/// function (and includes the object parameter), Args/NumArgs are the 6342/// arguments to the function call (not including the object 6343/// parameter). The caller needs to validate that the member 6344/// expression refers to a member function or an overloaded member 6345/// function. 6346Sema::OwningExprResult 6347Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 6348 SourceLocation LParenLoc, Expr **Args, 6349 unsigned NumArgs, SourceLocation *CommaLocs, 6350 SourceLocation RParenLoc) { 6351 // Dig out the member expression. This holds both the object 6352 // argument and the member function we're referring to. 6353 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 6354 6355 MemberExpr *MemExpr; 6356 CXXMethodDecl *Method = 0; 6357 DeclAccessPair FoundDecl = DeclAccessPair::make(0, AS_public); 6358 NestedNameSpecifier *Qualifier = 0; 6359 if (isa<MemberExpr>(NakedMemExpr)) { 6360 MemExpr = cast<MemberExpr>(NakedMemExpr); 6361 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 6362 FoundDecl = MemExpr->getFoundDecl(); 6363 Qualifier = MemExpr->getQualifier(); 6364 } else { 6365 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 6366 Qualifier = UnresExpr->getQualifier(); 6367 6368 QualType ObjectType = UnresExpr->getBaseType(); 6369 6370 // Add overload candidates 6371 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc()); 6372 6373 // FIXME: avoid copy. 6374 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6375 if (UnresExpr->hasExplicitTemplateArgs()) { 6376 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6377 TemplateArgs = &TemplateArgsBuffer; 6378 } 6379 6380 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 6381 E = UnresExpr->decls_end(); I != E; ++I) { 6382 6383 NamedDecl *Func = *I; 6384 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 6385 if (isa<UsingShadowDecl>(Func)) 6386 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 6387 6388 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 6389 // If explicit template arguments were provided, we can't call a 6390 // non-template member function. 6391 if (TemplateArgs) 6392 continue; 6393 6394 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, 6395 Args, NumArgs, 6396 CandidateSet, /*SuppressUserConversions=*/false); 6397 } else { 6398 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 6399 I.getPair(), ActingDC, TemplateArgs, 6400 ObjectType, Args, NumArgs, 6401 CandidateSet, 6402 /*SuppressUsedConversions=*/false); 6403 } 6404 } 6405 6406 DeclarationName DeclName = UnresExpr->getMemberName(); 6407 6408 OverloadCandidateSet::iterator Best; 6409 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 6410 case OR_Success: 6411 Method = cast<CXXMethodDecl>(Best->Function); 6412 FoundDecl = Best->FoundDecl; 6413 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); 6414 break; 6415 6416 case OR_No_Viable_Function: 6417 Diag(UnresExpr->getMemberLoc(), 6418 diag::err_ovl_no_viable_member_function_in_call) 6419 << DeclName << MemExprE->getSourceRange(); 6420 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6421 // FIXME: Leaking incoming expressions! 6422 return ExprError(); 6423 6424 case OR_Ambiguous: 6425 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 6426 << DeclName << MemExprE->getSourceRange(); 6427 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6428 // FIXME: Leaking incoming expressions! 6429 return ExprError(); 6430 6431 case OR_Deleted: 6432 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 6433 << Best->Function->isDeleted() 6434 << DeclName << MemExprE->getSourceRange(); 6435 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6436 // FIXME: Leaking incoming expressions! 6437 return ExprError(); 6438 } 6439 6440 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); 6441 6442 // If overload resolution picked a static member, build a 6443 // non-member call based on that function. 6444 if (Method->isStatic()) { 6445 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 6446 Args, NumArgs, RParenLoc); 6447 } 6448 6449 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 6450 } 6451 6452 assert(Method && "Member call to something that isn't a method?"); 6453 ExprOwningPtr<CXXMemberCallExpr> 6454 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 6455 NumArgs, 6456 Method->getResultType().getNonReferenceType(), 6457 RParenLoc)); 6458 6459 // Check for a valid return type. 6460 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 6461 TheCall.get(), Method)) 6462 return ExprError(); 6463 6464 // Convert the object argument (for a non-static member function call). 6465 // We only need to do this if there was actually an overload; otherwise 6466 // it was done at lookup. 6467 Expr *ObjectArg = MemExpr->getBase(); 6468 if (!Method->isStatic() && 6469 PerformObjectArgumentInitialization(ObjectArg, Qualifier, 6470 FoundDecl, Method)) 6471 return ExprError(); 6472 MemExpr->setBase(ObjectArg); 6473 6474 // Convert the rest of the arguments 6475 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 6476 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 6477 RParenLoc)) 6478 return ExprError(); 6479 6480 if (CheckFunctionCall(Method, TheCall.get())) 6481 return ExprError(); 6482 6483 return MaybeBindToTemporary(TheCall.release()); 6484} 6485 6486/// BuildCallToObjectOfClassType - Build a call to an object of class 6487/// type (C++ [over.call.object]), which can end up invoking an 6488/// overloaded function call operator (@c operator()) or performing a 6489/// user-defined conversion on the object argument. 6490Sema::ExprResult 6491Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 6492 SourceLocation LParenLoc, 6493 Expr **Args, unsigned NumArgs, 6494 SourceLocation *CommaLocs, 6495 SourceLocation RParenLoc) { 6496 assert(Object->getType()->isRecordType() && "Requires object type argument"); 6497 const RecordType *Record = Object->getType()->getAs<RecordType>(); 6498 6499 // C++ [over.call.object]p1: 6500 // If the primary-expression E in the function call syntax 6501 // evaluates to a class object of type "cv T", then the set of 6502 // candidate functions includes at least the function call 6503 // operators of T. The function call operators of T are obtained by 6504 // ordinary lookup of the name operator() in the context of 6505 // (E).operator(). 6506 OverloadCandidateSet CandidateSet(LParenLoc); 6507 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 6508 6509 if (RequireCompleteType(LParenLoc, Object->getType(), 6510 PDiag(diag::err_incomplete_object_call) 6511 << Object->getSourceRange())) 6512 return true; 6513 6514 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 6515 LookupQualifiedName(R, Record->getDecl()); 6516 R.suppressDiagnostics(); 6517 6518 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6519 Oper != OperEnd; ++Oper) { 6520 AddMethodCandidate(Oper.getPair(), Object->getType(), 6521 Args, NumArgs, CandidateSet, 6522 /*SuppressUserConversions=*/ false); 6523 } 6524 6525 // C++ [over.call.object]p2: 6526 // In addition, for each conversion function declared in T of the 6527 // form 6528 // 6529 // operator conversion-type-id () cv-qualifier; 6530 // 6531 // where cv-qualifier is the same cv-qualification as, or a 6532 // greater cv-qualification than, cv, and where conversion-type-id 6533 // denotes the type "pointer to function of (P1,...,Pn) returning 6534 // R", or the type "reference to pointer to function of 6535 // (P1,...,Pn) returning R", or the type "reference to function 6536 // of (P1,...,Pn) returning R", a surrogate call function [...] 6537 // is also considered as a candidate function. Similarly, 6538 // surrogate call functions are added to the set of candidate 6539 // functions for each conversion function declared in an 6540 // accessible base class provided the function is not hidden 6541 // within T by another intervening declaration. 6542 const UnresolvedSetImpl *Conversions 6543 = cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); 6544 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 6545 E = Conversions->end(); I != E; ++I) { 6546 NamedDecl *D = *I; 6547 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 6548 if (isa<UsingShadowDecl>(D)) 6549 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 6550 6551 // Skip over templated conversion functions; they aren't 6552 // surrogates. 6553 if (isa<FunctionTemplateDecl>(D)) 6554 continue; 6555 6556 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 6557 6558 // Strip the reference type (if any) and then the pointer type (if 6559 // any) to get down to what might be a function type. 6560 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 6561 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 6562 ConvType = ConvPtrType->getPointeeType(); 6563 6564 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 6565 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, 6566 Object->getType(), Args, NumArgs, 6567 CandidateSet); 6568 } 6569 6570 // Perform overload resolution. 6571 OverloadCandidateSet::iterator Best; 6572 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 6573 case OR_Success: 6574 // Overload resolution succeeded; we'll build the appropriate call 6575 // below. 6576 break; 6577 6578 case OR_No_Viable_Function: 6579 if (CandidateSet.empty()) 6580 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 6581 << Object->getType() << /*call*/ 1 6582 << Object->getSourceRange(); 6583 else 6584 Diag(Object->getSourceRange().getBegin(), 6585 diag::err_ovl_no_viable_object_call) 6586 << Object->getType() << Object->getSourceRange(); 6587 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6588 break; 6589 6590 case OR_Ambiguous: 6591 Diag(Object->getSourceRange().getBegin(), 6592 diag::err_ovl_ambiguous_object_call) 6593 << Object->getType() << Object->getSourceRange(); 6594 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6595 break; 6596 6597 case OR_Deleted: 6598 Diag(Object->getSourceRange().getBegin(), 6599 diag::err_ovl_deleted_object_call) 6600 << Best->Function->isDeleted() 6601 << Object->getType() << Object->getSourceRange(); 6602 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6603 break; 6604 } 6605 6606 if (Best == CandidateSet.end()) { 6607 // We had an error; delete all of the subexpressions and return 6608 // the error. 6609 Object->Destroy(Context); 6610 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6611 Args[ArgIdx]->Destroy(Context); 6612 return true; 6613 } 6614 6615 if (Best->Function == 0) { 6616 // Since there is no function declaration, this is one of the 6617 // surrogate candidates. Dig out the conversion function. 6618 CXXConversionDecl *Conv 6619 = cast<CXXConversionDecl>( 6620 Best->Conversions[0].UserDefined.ConversionFunction); 6621 6622 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6623 6624 // We selected one of the surrogate functions that converts the 6625 // object parameter to a function pointer. Perform the conversion 6626 // on the object argument, then let ActOnCallExpr finish the job. 6627 6628 // Create an implicit member expr to refer to the conversion operator. 6629 // and then call it. 6630 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Best->FoundDecl, 6631 Conv); 6632 6633 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 6634 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 6635 CommaLocs, RParenLoc).result(); 6636 } 6637 6638 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6639 6640 // We found an overloaded operator(). Build a CXXOperatorCallExpr 6641 // that calls this method, using Object for the implicit object 6642 // parameter and passing along the remaining arguments. 6643 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6644 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6645 6646 unsigned NumArgsInProto = Proto->getNumArgs(); 6647 unsigned NumArgsToCheck = NumArgs; 6648 6649 // Build the full argument list for the method call (the 6650 // implicit object parameter is placed at the beginning of the 6651 // list). 6652 Expr **MethodArgs; 6653 if (NumArgs < NumArgsInProto) { 6654 NumArgsToCheck = NumArgsInProto; 6655 MethodArgs = new Expr*[NumArgsInProto + 1]; 6656 } else { 6657 MethodArgs = new Expr*[NumArgs + 1]; 6658 } 6659 MethodArgs[0] = Object; 6660 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6661 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 6662 6663 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 6664 SourceLocation()); 6665 UsualUnaryConversions(NewFn); 6666 6667 // Once we've built TheCall, all of the expressions are properly 6668 // owned. 6669 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6670 ExprOwningPtr<CXXOperatorCallExpr> 6671 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 6672 MethodArgs, NumArgs + 1, 6673 ResultTy, RParenLoc)); 6674 delete [] MethodArgs; 6675 6676 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 6677 Method)) 6678 return true; 6679 6680 // We may have default arguments. If so, we need to allocate more 6681 // slots in the call for them. 6682 if (NumArgs < NumArgsInProto) 6683 TheCall->setNumArgs(Context, NumArgsInProto + 1); 6684 else if (NumArgs > NumArgsInProto) 6685 NumArgsToCheck = NumArgsInProto; 6686 6687 bool IsError = false; 6688 6689 // Initialize the implicit object parameter. 6690 IsError |= PerformObjectArgumentInitialization(Object, /*Qualifier=*/0, 6691 Best->FoundDecl, Method); 6692 TheCall->setArg(0, Object); 6693 6694 6695 // Check the argument types. 6696 for (unsigned i = 0; i != NumArgsToCheck; i++) { 6697 Expr *Arg; 6698 if (i < NumArgs) { 6699 Arg = Args[i]; 6700 6701 // Pass the argument. 6702 6703 OwningExprResult InputInit 6704 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6705 Method->getParamDecl(i)), 6706 SourceLocation(), Owned(Arg)); 6707 6708 IsError |= InputInit.isInvalid(); 6709 Arg = InputInit.takeAs<Expr>(); 6710 } else { 6711 OwningExprResult DefArg 6712 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 6713 if (DefArg.isInvalid()) { 6714 IsError = true; 6715 break; 6716 } 6717 6718 Arg = DefArg.takeAs<Expr>(); 6719 } 6720 6721 TheCall->setArg(i + 1, Arg); 6722 } 6723 6724 // If this is a variadic call, handle args passed through "...". 6725 if (Proto->isVariadic()) { 6726 // Promote the arguments (C99 6.5.2.2p7). 6727 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 6728 Expr *Arg = Args[i]; 6729 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 6730 TheCall->setArg(i + 1, Arg); 6731 } 6732 } 6733 6734 if (IsError) return true; 6735 6736 if (CheckFunctionCall(Method, TheCall.get())) 6737 return true; 6738 6739 return MaybeBindToTemporary(TheCall.release()).result(); 6740} 6741 6742/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 6743/// (if one exists), where @c Base is an expression of class type and 6744/// @c Member is the name of the member we're trying to find. 6745Sema::OwningExprResult 6746Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 6747 Expr *Base = static_cast<Expr *>(BaseIn.get()); 6748 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 6749 6750 SourceLocation Loc = Base->getExprLoc(); 6751 6752 // C++ [over.ref]p1: 6753 // 6754 // [...] An expression x->m is interpreted as (x.operator->())->m 6755 // for a class object x of type T if T::operator->() exists and if 6756 // the operator is selected as the best match function by the 6757 // overload resolution mechanism (13.3). 6758 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 6759 OverloadCandidateSet CandidateSet(Loc); 6760 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 6761 6762 if (RequireCompleteType(Loc, Base->getType(), 6763 PDiag(diag::err_typecheck_incomplete_tag) 6764 << Base->getSourceRange())) 6765 return ExprError(); 6766 6767 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 6768 LookupQualifiedName(R, BaseRecord->getDecl()); 6769 R.suppressDiagnostics(); 6770 6771 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6772 Oper != OperEnd; ++Oper) { 6773 AddMethodCandidate(Oper.getPair(), Base->getType(), 0, 0, CandidateSet, 6774 /*SuppressUserConversions=*/false); 6775 } 6776 6777 // Perform overload resolution. 6778 OverloadCandidateSet::iterator Best; 6779 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6780 case OR_Success: 6781 // Overload resolution succeeded; we'll build the call below. 6782 break; 6783 6784 case OR_No_Viable_Function: 6785 if (CandidateSet.empty()) 6786 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 6787 << Base->getType() << Base->getSourceRange(); 6788 else 6789 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6790 << "operator->" << Base->getSourceRange(); 6791 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6792 return ExprError(); 6793 6794 case OR_Ambiguous: 6795 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6796 << "->" << Base->getSourceRange(); 6797 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, &Base, 1); 6798 return ExprError(); 6799 6800 case OR_Deleted: 6801 Diag(OpLoc, diag::err_ovl_deleted_oper) 6802 << Best->Function->isDeleted() 6803 << "->" << Base->getSourceRange(); 6804 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6805 return ExprError(); 6806 } 6807 6808 CheckMemberOperatorAccess(OpLoc, Base, 0, Best->FoundDecl); 6809 6810 // Convert the object parameter. 6811 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6812 if (PerformObjectArgumentInitialization(Base, /*Qualifier=*/0, 6813 Best->FoundDecl, Method)) 6814 return ExprError(); 6815 6816 // No concerns about early exits now. 6817 BaseIn.release(); 6818 6819 // Build the operator call. 6820 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 6821 SourceLocation()); 6822 UsualUnaryConversions(FnExpr); 6823 6824 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6825 ExprOwningPtr<CXXOperatorCallExpr> 6826 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 6827 &Base, 1, ResultTy, OpLoc)); 6828 6829 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 6830 Method)) 6831 return ExprError(); 6832 return move(TheCall); 6833} 6834 6835/// FixOverloadedFunctionReference - E is an expression that refers to 6836/// a C++ overloaded function (possibly with some parentheses and 6837/// perhaps a '&' around it). We have resolved the overloaded function 6838/// to the function declaration Fn, so patch up the expression E to 6839/// refer (possibly indirectly) to Fn. Returns the new expr. 6840Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, 6841 FunctionDecl *Fn) { 6842 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 6843 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), 6844 Found, Fn); 6845 if (SubExpr == PE->getSubExpr()) 6846 return PE->Retain(); 6847 6848 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 6849 } 6850 6851 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6852 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), 6853 Found, Fn); 6854 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 6855 SubExpr->getType()) && 6856 "Implicit cast type cannot be determined from overload"); 6857 if (SubExpr == ICE->getSubExpr()) 6858 return ICE->Retain(); 6859 6860 return new (Context) ImplicitCastExpr(ICE->getType(), 6861 ICE->getCastKind(), 6862 SubExpr, CXXBaseSpecifierArray(), 6863 ICE->isLvalueCast()); 6864 } 6865 6866 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 6867 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 6868 "Can only take the address of an overloaded function"); 6869 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 6870 if (Method->isStatic()) { 6871 // Do nothing: static member functions aren't any different 6872 // from non-member functions. 6873 } else { 6874 // Fix the sub expression, which really has to be an 6875 // UnresolvedLookupExpr holding an overloaded member function 6876 // or template. 6877 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6878 Found, Fn); 6879 if (SubExpr == UnOp->getSubExpr()) 6880 return UnOp->Retain(); 6881 6882 assert(isa<DeclRefExpr>(SubExpr) 6883 && "fixed to something other than a decl ref"); 6884 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 6885 && "fixed to a member ref with no nested name qualifier"); 6886 6887 // We have taken the address of a pointer to member 6888 // function. Perform the computation here so that we get the 6889 // appropriate pointer to member type. 6890 QualType ClassType 6891 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 6892 QualType MemPtrType 6893 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 6894 6895 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6896 MemPtrType, UnOp->getOperatorLoc()); 6897 } 6898 } 6899 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6900 Found, Fn); 6901 if (SubExpr == UnOp->getSubExpr()) 6902 return UnOp->Retain(); 6903 6904 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6905 Context.getPointerType(SubExpr->getType()), 6906 UnOp->getOperatorLoc()); 6907 } 6908 6909 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 6910 // FIXME: avoid copy. 6911 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6912 if (ULE->hasExplicitTemplateArgs()) { 6913 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 6914 TemplateArgs = &TemplateArgsBuffer; 6915 } 6916 6917 return DeclRefExpr::Create(Context, 6918 ULE->getQualifier(), 6919 ULE->getQualifierRange(), 6920 Fn, 6921 ULE->getNameLoc(), 6922 Fn->getType(), 6923 TemplateArgs); 6924 } 6925 6926 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 6927 // FIXME: avoid copy. 6928 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6929 if (MemExpr->hasExplicitTemplateArgs()) { 6930 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6931 TemplateArgs = &TemplateArgsBuffer; 6932 } 6933 6934 Expr *Base; 6935 6936 // If we're filling in 6937 if (MemExpr->isImplicitAccess()) { 6938 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 6939 return DeclRefExpr::Create(Context, 6940 MemExpr->getQualifier(), 6941 MemExpr->getQualifierRange(), 6942 Fn, 6943 MemExpr->getMemberLoc(), 6944 Fn->getType(), 6945 TemplateArgs); 6946 } else { 6947 SourceLocation Loc = MemExpr->getMemberLoc(); 6948 if (MemExpr->getQualifier()) 6949 Loc = MemExpr->getQualifierRange().getBegin(); 6950 Base = new (Context) CXXThisExpr(Loc, 6951 MemExpr->getBaseType(), 6952 /*isImplicit=*/true); 6953 } 6954 } else 6955 Base = MemExpr->getBase()->Retain(); 6956 6957 return MemberExpr::Create(Context, Base, 6958 MemExpr->isArrow(), 6959 MemExpr->getQualifier(), 6960 MemExpr->getQualifierRange(), 6961 Fn, 6962 Found, 6963 MemExpr->getMemberLoc(), 6964 TemplateArgs, 6965 Fn->getType()); 6966 } 6967 6968 assert(false && "Invalid reference to overloaded function"); 6969 return E->Retain(); 6970} 6971 6972Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 6973 DeclAccessPair Found, 6974 FunctionDecl *Fn) { 6975 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Found, Fn)); 6976} 6977 6978} // end namespace clang 6979