SemaOverload.cpp revision 66aba360b69b620be996e81eb370dd6e00c50361
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->getNameAsString() << "'"; 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. 439/// If @p ForceRValue, then overloading is performed as if From was an rvalue, 440/// no matter its actual lvalueness. 441/// If @p UserCast, the implicit conversion is being done for a user-specified 442/// cast. 443ImplicitConversionSequence 444Sema::TryImplicitConversion(Expr* From, QualType ToType, 445 bool SuppressUserConversions, 446 bool AllowExplicit, bool ForceRValue, 447 bool InOverloadResolution, 448 bool UserCast) { 449 ImplicitConversionSequence ICS; 450 if (IsStandardConversion(From, ToType, InOverloadResolution, ICS.Standard)) { 451 ICS.setStandard(); 452 return ICS; 453 } 454 455 if (!getLangOptions().CPlusPlus) { 456 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 457 return ICS; 458 } 459 460 OverloadCandidateSet Conversions(From->getExprLoc()); 461 OverloadingResult UserDefResult 462 = IsUserDefinedConversion(From, ToType, ICS.UserDefined, Conversions, 463 !SuppressUserConversions, AllowExplicit, 464 UserCast); 465 466 if (UserDefResult == OR_Success) { 467 ICS.setUserDefined(); 468 // C++ [over.ics.user]p4: 469 // A conversion of an expression of class type to the same class 470 // type is given Exact Match rank, and a conversion of an 471 // expression of class type to a base class of that type is 472 // given Conversion rank, in spite of the fact that a copy 473 // constructor (i.e., a user-defined conversion function) is 474 // called for those cases. 475 if (CXXConstructorDecl *Constructor 476 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 477 QualType FromCanon 478 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 479 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 480 if (Constructor->isCopyConstructor() && 481 (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) { 482 // Turn this into a "standard" conversion sequence, so that it 483 // gets ranked with standard conversion sequences. 484 ICS.setStandard(); 485 ICS.Standard.setAsIdentityConversion(); 486 ICS.Standard.setFromType(From->getType()); 487 ICS.Standard.setAllToTypes(ToType); 488 ICS.Standard.CopyConstructor = Constructor; 489 if (ToCanon != FromCanon) 490 ICS.Standard.Second = ICK_Derived_To_Base; 491 } 492 } 493 494 // C++ [over.best.ics]p4: 495 // However, when considering the argument of a user-defined 496 // conversion function that is a candidate by 13.3.1.3 when 497 // invoked for the copying of the temporary in the second step 498 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 499 // 13.3.1.6 in all cases, only standard conversion sequences and 500 // ellipsis conversion sequences are allowed. 501 if (SuppressUserConversions && ICS.isUserDefined()) { 502 ICS.setBad(BadConversionSequence::suppressed_user, From, ToType); 503 } 504 } else if (UserDefResult == OR_Ambiguous && !SuppressUserConversions) { 505 ICS.setAmbiguous(); 506 ICS.Ambiguous.setFromType(From->getType()); 507 ICS.Ambiguous.setToType(ToType); 508 for (OverloadCandidateSet::iterator Cand = Conversions.begin(); 509 Cand != Conversions.end(); ++Cand) 510 if (Cand->Viable) 511 ICS.Ambiguous.addConversion(Cand->Function); 512 } else { 513 ICS.setBad(BadConversionSequence::no_conversion, From, ToType); 514 } 515 516 return ICS; 517} 518 519/// \brief Determine whether the conversion from FromType to ToType is a valid 520/// conversion that strips "noreturn" off the nested function type. 521static bool IsNoReturnConversion(ASTContext &Context, QualType FromType, 522 QualType ToType, QualType &ResultTy) { 523 if (Context.hasSameUnqualifiedType(FromType, ToType)) 524 return false; 525 526 // Strip the noreturn off the type we're converting from; noreturn can 527 // safely be removed. 528 FromType = Context.getNoReturnType(FromType, false); 529 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 530 return false; 531 532 ResultTy = FromType; 533 return true; 534} 535 536/// IsStandardConversion - Determines whether there is a standard 537/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 538/// expression From to the type ToType. Standard conversion sequences 539/// only consider non-class types; for conversions that involve class 540/// types, use TryImplicitConversion. If a conversion exists, SCS will 541/// contain the standard conversion sequence required to perform this 542/// conversion and this routine will return true. Otherwise, this 543/// routine will return false and the value of SCS is unspecified. 544bool 545Sema::IsStandardConversion(Expr* From, QualType ToType, 546 bool InOverloadResolution, 547 StandardConversionSequence &SCS) { 548 QualType FromType = From->getType(); 549 550 // Standard conversions (C++ [conv]) 551 SCS.setAsIdentityConversion(); 552 SCS.DeprecatedStringLiteralToCharPtr = false; 553 SCS.IncompatibleObjC = false; 554 SCS.setFromType(FromType); 555 SCS.CopyConstructor = 0; 556 557 // There are no standard conversions for class types in C++, so 558 // abort early. When overloading in C, however, we do permit 559 if (FromType->isRecordType() || ToType->isRecordType()) { 560 if (getLangOptions().CPlusPlus) 561 return false; 562 563 // When we're overloading in C, we allow, as standard conversions, 564 } 565 566 // The first conversion can be an lvalue-to-rvalue conversion, 567 // array-to-pointer conversion, or function-to-pointer conversion 568 // (C++ 4p1). 569 570 DeclAccessPair AccessPair; 571 572 // Lvalue-to-rvalue conversion (C++ 4.1): 573 // An lvalue (3.10) of a non-function, non-array type T can be 574 // converted to an rvalue. 575 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 576 if (argIsLvalue == Expr::LV_Valid && 577 !FromType->isFunctionType() && !FromType->isArrayType() && 578 Context.getCanonicalType(FromType) != Context.OverloadTy) { 579 SCS.First = ICK_Lvalue_To_Rvalue; 580 581 // If T is a non-class type, the type of the rvalue is the 582 // cv-unqualified version of T. Otherwise, the type of the rvalue 583 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 584 // just strip the qualifiers because they don't matter. 585 FromType = FromType.getUnqualifiedType(); 586 } else if (FromType->isArrayType()) { 587 // Array-to-pointer conversion (C++ 4.2) 588 SCS.First = ICK_Array_To_Pointer; 589 590 // An lvalue or rvalue of type "array of N T" or "array of unknown 591 // bound of T" can be converted to an rvalue of type "pointer to 592 // T" (C++ 4.2p1). 593 FromType = Context.getArrayDecayedType(FromType); 594 595 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 596 // This conversion is deprecated. (C++ D.4). 597 SCS.DeprecatedStringLiteralToCharPtr = true; 598 599 // For the purpose of ranking in overload resolution 600 // (13.3.3.1.1), this conversion is considered an 601 // array-to-pointer conversion followed by a qualification 602 // conversion (4.4). (C++ 4.2p2) 603 SCS.Second = ICK_Identity; 604 SCS.Third = ICK_Qualification; 605 SCS.setAllToTypes(FromType); 606 return true; 607 } 608 } else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 609 // Function-to-pointer conversion (C++ 4.3). 610 SCS.First = ICK_Function_To_Pointer; 611 612 // An lvalue of function type T can be converted to an rvalue of 613 // type "pointer to T." The result is a pointer to the 614 // function. (C++ 4.3p1). 615 FromType = Context.getPointerType(FromType); 616 } else if (From->getType() == Context.OverloadTy) { 617 if (FunctionDecl *Fn 618 = ResolveAddressOfOverloadedFunction(From, ToType, false, 619 AccessPair)) { 620 // Address of overloaded function (C++ [over.over]). 621 SCS.First = ICK_Function_To_Pointer; 622 623 // We were able to resolve the address of the overloaded function, 624 // so we can convert to the type of that function. 625 FromType = Fn->getType(); 626 if (ToType->isLValueReferenceType()) 627 FromType = Context.getLValueReferenceType(FromType); 628 else if (ToType->isRValueReferenceType()) 629 FromType = Context.getRValueReferenceType(FromType); 630 else if (ToType->isMemberPointerType()) { 631 // Resolve address only succeeds if both sides are member pointers, 632 // but it doesn't have to be the same class. See DR 247. 633 // Note that this means that the type of &Derived::fn can be 634 // Ret (Base::*)(Args) if the fn overload actually found is from the 635 // base class, even if it was brought into the derived class via a 636 // using declaration. The standard isn't clear on this issue at all. 637 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 638 FromType = Context.getMemberPointerType(FromType, 639 Context.getTypeDeclType(M->getParent()).getTypePtr()); 640 } else { 641 FromType = Context.getPointerType(FromType); 642 } 643 } else { 644 return false; 645 } 646 } else { 647 // We don't require any conversions for the first step. 648 SCS.First = ICK_Identity; 649 } 650 SCS.setToType(0, FromType); 651 652 // The second conversion can be an integral promotion, floating 653 // point promotion, integral conversion, floating point conversion, 654 // floating-integral conversion, pointer conversion, 655 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 656 // For overloading in C, this can also be a "compatible-type" 657 // conversion. 658 bool IncompatibleObjC = false; 659 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 660 // The unqualified versions of the types are the same: there's no 661 // conversion to do. 662 SCS.Second = ICK_Identity; 663 } else if (IsIntegralPromotion(From, FromType, ToType)) { 664 // Integral promotion (C++ 4.5). 665 SCS.Second = ICK_Integral_Promotion; 666 FromType = ToType.getUnqualifiedType(); 667 } else if (IsFloatingPointPromotion(FromType, ToType)) { 668 // Floating point promotion (C++ 4.6). 669 SCS.Second = ICK_Floating_Promotion; 670 FromType = ToType.getUnqualifiedType(); 671 } else if (IsComplexPromotion(FromType, ToType)) { 672 // Complex promotion (Clang extension) 673 SCS.Second = ICK_Complex_Promotion; 674 FromType = ToType.getUnqualifiedType(); 675 } else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 676 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 677 // Integral conversions (C++ 4.7). 678 SCS.Second = ICK_Integral_Conversion; 679 FromType = ToType.getUnqualifiedType(); 680 } else if (FromType->isComplexType() && ToType->isComplexType()) { 681 // Complex conversions (C99 6.3.1.6) 682 SCS.Second = ICK_Complex_Conversion; 683 FromType = ToType.getUnqualifiedType(); 684 } else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 685 (ToType->isComplexType() && FromType->isArithmeticType())) { 686 // Complex-real conversions (C99 6.3.1.7) 687 SCS.Second = ICK_Complex_Real; 688 FromType = ToType.getUnqualifiedType(); 689 } else if (FromType->isFloatingType() && ToType->isFloatingType()) { 690 // Floating point conversions (C++ 4.8). 691 SCS.Second = ICK_Floating_Conversion; 692 FromType = ToType.getUnqualifiedType(); 693 } else if ((FromType->isFloatingType() && 694 ToType->isIntegralType() && (!ToType->isBooleanType() && 695 !ToType->isEnumeralType())) || 696 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 697 ToType->isFloatingType())) { 698 // Floating-integral conversions (C++ 4.9). 699 SCS.Second = ICK_Floating_Integral; 700 FromType = ToType.getUnqualifiedType(); 701 } else if (IsPointerConversion(From, FromType, ToType, InOverloadResolution, 702 FromType, IncompatibleObjC)) { 703 // Pointer conversions (C++ 4.10). 704 SCS.Second = ICK_Pointer_Conversion; 705 SCS.IncompatibleObjC = IncompatibleObjC; 706 } else if (IsMemberPointerConversion(From, FromType, ToType, 707 InOverloadResolution, FromType)) { 708 // Pointer to member conversions (4.11). 709 SCS.Second = ICK_Pointer_Member; 710 } else if (ToType->isBooleanType() && 711 (FromType->isArithmeticType() || 712 FromType->isEnumeralType() || 713 FromType->isAnyPointerType() || 714 FromType->isBlockPointerType() || 715 FromType->isMemberPointerType() || 716 FromType->isNullPtrType())) { 717 // Boolean conversions (C++ 4.12). 718 SCS.Second = ICK_Boolean_Conversion; 719 FromType = Context.BoolTy; 720 } else if (!getLangOptions().CPlusPlus && 721 Context.typesAreCompatible(ToType, FromType)) { 722 // Compatible conversions (Clang extension for C function overloading) 723 SCS.Second = ICK_Compatible_Conversion; 724 } else if (IsNoReturnConversion(Context, FromType, ToType, FromType)) { 725 // Treat a conversion that strips "noreturn" as an identity conversion. 726 SCS.Second = ICK_NoReturn_Adjustment; 727 } else { 728 // No second conversion required. 729 SCS.Second = ICK_Identity; 730 } 731 SCS.setToType(1, FromType); 732 733 QualType CanonFrom; 734 QualType CanonTo; 735 // The third conversion can be a qualification conversion (C++ 4p1). 736 if (IsQualificationConversion(FromType, ToType)) { 737 SCS.Third = ICK_Qualification; 738 FromType = ToType; 739 CanonFrom = Context.getCanonicalType(FromType); 740 CanonTo = Context.getCanonicalType(ToType); 741 } else { 742 // No conversion required 743 SCS.Third = ICK_Identity; 744 745 // C++ [over.best.ics]p6: 746 // [...] Any difference in top-level cv-qualification is 747 // subsumed by the initialization itself and does not constitute 748 // a conversion. [...] 749 CanonFrom = Context.getCanonicalType(FromType); 750 CanonTo = Context.getCanonicalType(ToType); 751 if (CanonFrom.getLocalUnqualifiedType() 752 == CanonTo.getLocalUnqualifiedType() && 753 CanonFrom.getLocalCVRQualifiers() != CanonTo.getLocalCVRQualifiers()) { 754 FromType = ToType; 755 CanonFrom = CanonTo; 756 } 757 } 758 SCS.setToType(2, FromType); 759 760 // If we have not converted the argument type to the parameter type, 761 // this is a bad conversion sequence. 762 if (CanonFrom != CanonTo) 763 return false; 764 765 return true; 766} 767 768/// IsIntegralPromotion - Determines whether the conversion from the 769/// expression From (whose potentially-adjusted type is FromType) to 770/// ToType is an integral promotion (C++ 4.5). If so, returns true and 771/// sets PromotedType to the promoted type. 772bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { 773 const BuiltinType *To = ToType->getAs<BuiltinType>(); 774 // All integers are built-in. 775 if (!To) { 776 return false; 777 } 778 779 // An rvalue of type char, signed char, unsigned char, short int, or 780 // unsigned short int can be converted to an rvalue of type int if 781 // int can represent all the values of the source type; otherwise, 782 // the source rvalue can be converted to an rvalue of type unsigned 783 // int (C++ 4.5p1). 784 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() && 785 !FromType->isEnumeralType()) { 786 if (// We can promote any signed, promotable integer type to an int 787 (FromType->isSignedIntegerType() || 788 // We can promote any unsigned integer type whose size is 789 // less than int to an int. 790 (!FromType->isSignedIntegerType() && 791 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 792 return To->getKind() == BuiltinType::Int; 793 } 794 795 return To->getKind() == BuiltinType::UInt; 796 } 797 798 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 799 // can be converted to an rvalue of the first of the following types 800 // that can represent all the values of its underlying type: int, 801 // unsigned int, long, or unsigned long (C++ 4.5p2). 802 803 // We pre-calculate the promotion type for enum types. 804 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) 805 if (ToType->isIntegerType()) 806 return Context.hasSameUnqualifiedType(ToType, 807 FromEnumType->getDecl()->getPromotionType()); 808 809 if (FromType->isWideCharType() && ToType->isIntegerType()) { 810 // Determine whether the type we're converting from is signed or 811 // unsigned. 812 bool FromIsSigned; 813 uint64_t FromSize = Context.getTypeSize(FromType); 814 815 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 816 FromIsSigned = true; 817 818 // The types we'll try to promote to, in the appropriate 819 // order. Try each of these types. 820 QualType PromoteTypes[6] = { 821 Context.IntTy, Context.UnsignedIntTy, 822 Context.LongTy, Context.UnsignedLongTy , 823 Context.LongLongTy, Context.UnsignedLongLongTy 824 }; 825 for (int Idx = 0; Idx < 6; ++Idx) { 826 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 827 if (FromSize < ToSize || 828 (FromSize == ToSize && 829 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 830 // We found the type that we can promote to. If this is the 831 // type we wanted, we have a promotion. Otherwise, no 832 // promotion. 833 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); 834 } 835 } 836 } 837 838 // An rvalue for an integral bit-field (9.6) can be converted to an 839 // rvalue of type int if int can represent all the values of the 840 // bit-field; otherwise, it can be converted to unsigned int if 841 // unsigned int can represent all the values of the bit-field. If 842 // the bit-field is larger yet, no integral promotion applies to 843 // it. If the bit-field has an enumerated type, it is treated as any 844 // other value of that type for promotion purposes (C++ 4.5p3). 845 // FIXME: We should delay checking of bit-fields until we actually perform the 846 // conversion. 847 using llvm::APSInt; 848 if (From) 849 if (FieldDecl *MemberDecl = From->getBitField()) { 850 APSInt BitWidth; 851 if (FromType->isIntegralType() && !FromType->isEnumeralType() && 852 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { 853 APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned()); 854 ToSize = Context.getTypeSize(ToType); 855 856 // Are we promoting to an int from a bitfield that fits in an int? 857 if (BitWidth < ToSize || 858 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 859 return To->getKind() == BuiltinType::Int; 860 } 861 862 // Are we promoting to an unsigned int from an unsigned bitfield 863 // that fits into an unsigned int? 864 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 865 return To->getKind() == BuiltinType::UInt; 866 } 867 868 return false; 869 } 870 } 871 872 // An rvalue of type bool can be converted to an rvalue of type int, 873 // with false becoming zero and true becoming one (C++ 4.5p4). 874 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 875 return true; 876 } 877 878 return false; 879} 880 881/// IsFloatingPointPromotion - Determines whether the conversion from 882/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 883/// returns true and sets PromotedType to the promoted type. 884bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { 885 /// An rvalue of type float can be converted to an rvalue of type 886 /// double. (C++ 4.6p1). 887 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) 888 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { 889 if (FromBuiltin->getKind() == BuiltinType::Float && 890 ToBuiltin->getKind() == BuiltinType::Double) 891 return true; 892 893 // C99 6.3.1.5p1: 894 // When a float is promoted to double or long double, or a 895 // double is promoted to long double [...]. 896 if (!getLangOptions().CPlusPlus && 897 (FromBuiltin->getKind() == BuiltinType::Float || 898 FromBuiltin->getKind() == BuiltinType::Double) && 899 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 900 return true; 901 } 902 903 return false; 904} 905 906/// \brief Determine if a conversion is a complex promotion. 907/// 908/// A complex promotion is defined as a complex -> complex conversion 909/// where the conversion between the underlying real types is a 910/// floating-point or integral promotion. 911bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 912 const ComplexType *FromComplex = FromType->getAs<ComplexType>(); 913 if (!FromComplex) 914 return false; 915 916 const ComplexType *ToComplex = ToType->getAs<ComplexType>(); 917 if (!ToComplex) 918 return false; 919 920 return IsFloatingPointPromotion(FromComplex->getElementType(), 921 ToComplex->getElementType()) || 922 IsIntegralPromotion(0, FromComplex->getElementType(), 923 ToComplex->getElementType()); 924} 925 926/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 927/// the pointer type FromPtr to a pointer to type ToPointee, with the 928/// same type qualifiers as FromPtr has on its pointee type. ToType, 929/// if non-empty, will be a pointer to ToType that may or may not have 930/// the right set of qualifiers on its pointee. 931static QualType 932BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 933 QualType ToPointee, QualType ToType, 934 ASTContext &Context) { 935 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 936 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 937 Qualifiers Quals = CanonFromPointee.getQualifiers(); 938 939 // Exact qualifier match -> return the pointer type we're converting to. 940 if (CanonToPointee.getLocalQualifiers() == Quals) { 941 // ToType is exactly what we need. Return it. 942 if (!ToType.isNull()) 943 return ToType; 944 945 // Build a pointer to ToPointee. It has the right qualifiers 946 // already. 947 return Context.getPointerType(ToPointee); 948 } 949 950 // Just build a canonical type that has the right qualifiers. 951 return Context.getPointerType( 952 Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), 953 Quals)); 954} 955 956/// BuildSimilarlyQualifiedObjCObjectPointerType - In a pointer conversion from 957/// the FromType, which is an objective-c pointer, to ToType, which may or may 958/// not have the right set of qualifiers. 959static QualType 960BuildSimilarlyQualifiedObjCObjectPointerType(QualType FromType, 961 QualType ToType, 962 ASTContext &Context) { 963 QualType CanonFromType = Context.getCanonicalType(FromType); 964 QualType CanonToType = Context.getCanonicalType(ToType); 965 Qualifiers Quals = CanonFromType.getQualifiers(); 966 967 // Exact qualifier match -> return the pointer type we're converting to. 968 if (CanonToType.getLocalQualifiers() == Quals) 969 return ToType; 970 971 // Just build a canonical type that has the right qualifiers. 972 return Context.getQualifiedType(CanonToType.getLocalUnqualifiedType(), Quals); 973} 974 975static bool isNullPointerConstantForConversion(Expr *Expr, 976 bool InOverloadResolution, 977 ASTContext &Context) { 978 // Handle value-dependent integral null pointer constants correctly. 979 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 980 if (Expr->isValueDependent() && !Expr->isTypeDependent() && 981 Expr->getType()->isIntegralType()) 982 return !InOverloadResolution; 983 984 return Expr->isNullPointerConstant(Context, 985 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 986 : Expr::NPC_ValueDependentIsNull); 987} 988 989/// IsPointerConversion - Determines whether the conversion of the 990/// expression From, which has the (possibly adjusted) type FromType, 991/// can be converted to the type ToType via a pointer conversion (C++ 992/// 4.10). If so, returns true and places the converted type (that 993/// might differ from ToType in its cv-qualifiers at some level) into 994/// ConvertedType. 995/// 996/// This routine also supports conversions to and from block pointers 997/// and conversions with Objective-C's 'id', 'id<protocols...>', and 998/// pointers to interfaces. FIXME: Once we've determined the 999/// appropriate overloading rules for Objective-C, we may want to 1000/// split the Objective-C checks into a different routine; however, 1001/// GCC seems to consider all of these conversions to be pointer 1002/// conversions, so for now they live here. IncompatibleObjC will be 1003/// set if the conversion is an allowed Objective-C conversion that 1004/// should result in a warning. 1005bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 1006 bool InOverloadResolution, 1007 QualType& ConvertedType, 1008 bool &IncompatibleObjC) { 1009 IncompatibleObjC = false; 1010 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 1011 return true; 1012 1013 // Conversion from a null pointer constant to any Objective-C pointer type. 1014 if (ToType->isObjCObjectPointerType() && 1015 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1016 ConvertedType = ToType; 1017 return true; 1018 } 1019 1020 // Blocks: Block pointers can be converted to void*. 1021 if (FromType->isBlockPointerType() && ToType->isPointerType() && 1022 ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) { 1023 ConvertedType = ToType; 1024 return true; 1025 } 1026 // Blocks: A null pointer constant can be converted to a block 1027 // pointer type. 1028 if (ToType->isBlockPointerType() && 1029 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1030 ConvertedType = ToType; 1031 return true; 1032 } 1033 1034 // If the left-hand-side is nullptr_t, the right side can be a null 1035 // pointer constant. 1036 if (ToType->isNullPtrType() && 1037 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1038 ConvertedType = ToType; 1039 return true; 1040 } 1041 1042 const PointerType* ToTypePtr = ToType->getAs<PointerType>(); 1043 if (!ToTypePtr) 1044 return false; 1045 1046 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 1047 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1048 ConvertedType = ToType; 1049 return true; 1050 } 1051 1052 // Beyond this point, both types need to be pointers 1053 // , including objective-c pointers. 1054 QualType ToPointeeType = ToTypePtr->getPointeeType(); 1055 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType()) { 1056 ConvertedType = BuildSimilarlyQualifiedObjCObjectPointerType(FromType, 1057 ToType, Context); 1058 return true; 1059 1060 } 1061 const PointerType *FromTypePtr = FromType->getAs<PointerType>(); 1062 if (!FromTypePtr) 1063 return false; 1064 1065 QualType FromPointeeType = FromTypePtr->getPointeeType(); 1066 1067 // An rvalue of type "pointer to cv T," where T is an object type, 1068 // can be converted to an rvalue of type "pointer to cv void" (C++ 1069 // 4.10p2). 1070 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 1071 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1072 ToPointeeType, 1073 ToType, Context); 1074 return true; 1075 } 1076 1077 // When we're overloading in C, we allow a special kind of pointer 1078 // conversion for compatible-but-not-identical pointee types. 1079 if (!getLangOptions().CPlusPlus && 1080 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 1081 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1082 ToPointeeType, 1083 ToType, Context); 1084 return true; 1085 } 1086 1087 // C++ [conv.ptr]p3: 1088 // 1089 // An rvalue of type "pointer to cv D," where D is a class type, 1090 // can be converted to an rvalue of type "pointer to cv B," where 1091 // B is a base class (clause 10) of D. If B is an inaccessible 1092 // (clause 11) or ambiguous (10.2) base class of D, a program that 1093 // necessitates this conversion is ill-formed. The result of the 1094 // conversion is a pointer to the base class sub-object of the 1095 // derived class object. The null pointer value is converted to 1096 // the null pointer value of the destination type. 1097 // 1098 // Note that we do not check for ambiguity or inaccessibility 1099 // here. That is handled by CheckPointerConversion. 1100 if (getLangOptions().CPlusPlus && 1101 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1102 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) && 1103 !RequireCompleteType(From->getLocStart(), FromPointeeType, PDiag()) && 1104 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 1105 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1106 ToPointeeType, 1107 ToType, Context); 1108 return true; 1109 } 1110 1111 return false; 1112} 1113 1114/// isObjCPointerConversion - Determines whether this is an 1115/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 1116/// with the same arguments and return values. 1117bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 1118 QualType& ConvertedType, 1119 bool &IncompatibleObjC) { 1120 if (!getLangOptions().ObjC1) 1121 return false; 1122 1123 // First, we handle all conversions on ObjC object pointer types. 1124 const ObjCObjectPointerType* ToObjCPtr = ToType->getAs<ObjCObjectPointerType>(); 1125 const ObjCObjectPointerType *FromObjCPtr = 1126 FromType->getAs<ObjCObjectPointerType>(); 1127 1128 if (ToObjCPtr && FromObjCPtr) { 1129 // Objective C++: We're able to convert between "id" or "Class" and a 1130 // pointer to any interface (in both directions). 1131 if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) { 1132 ConvertedType = ToType; 1133 return true; 1134 } 1135 // Conversions with Objective-C's id<...>. 1136 if ((FromObjCPtr->isObjCQualifiedIdType() || 1137 ToObjCPtr->isObjCQualifiedIdType()) && 1138 Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType, 1139 /*compare=*/false)) { 1140 ConvertedType = ToType; 1141 return true; 1142 } 1143 // Objective C++: We're able to convert from a pointer to an 1144 // interface to a pointer to a different interface. 1145 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { 1146 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType(); 1147 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType(); 1148 if (getLangOptions().CPlusPlus && LHS && RHS && 1149 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs( 1150 FromObjCPtr->getPointeeType())) 1151 return false; 1152 ConvertedType = ToType; 1153 return true; 1154 } 1155 1156 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { 1157 // Okay: this is some kind of implicit downcast of Objective-C 1158 // interfaces, which is permitted. However, we're going to 1159 // complain about it. 1160 IncompatibleObjC = true; 1161 ConvertedType = FromType; 1162 return true; 1163 } 1164 } 1165 // Beyond this point, both types need to be C pointers or block pointers. 1166 QualType ToPointeeType; 1167 if (const PointerType *ToCPtr = ToType->getAs<PointerType>()) 1168 ToPointeeType = ToCPtr->getPointeeType(); 1169 else if (const BlockPointerType *ToBlockPtr = 1170 ToType->getAs<BlockPointerType>()) { 1171 // Objective C++: We're able to convert from a pointer to any object 1172 // to a block pointer type. 1173 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) { 1174 ConvertedType = ToType; 1175 return true; 1176 } 1177 ToPointeeType = ToBlockPtr->getPointeeType(); 1178 } 1179 else if (FromType->getAs<BlockPointerType>() && 1180 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) { 1181 // Objective C++: We're able to convert from a block pointer type to a 1182 // pointer to any object. 1183 ConvertedType = ToType; 1184 return true; 1185 } 1186 else 1187 return false; 1188 1189 QualType FromPointeeType; 1190 if (const PointerType *FromCPtr = FromType->getAs<PointerType>()) 1191 FromPointeeType = FromCPtr->getPointeeType(); 1192 else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>()) 1193 FromPointeeType = FromBlockPtr->getPointeeType(); 1194 else 1195 return false; 1196 1197 // If we have pointers to pointers, recursively check whether this 1198 // is an Objective-C conversion. 1199 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1200 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1201 IncompatibleObjC)) { 1202 // We always complain about this conversion. 1203 IncompatibleObjC = true; 1204 ConvertedType = ToType; 1205 return true; 1206 } 1207 // Allow conversion of pointee being objective-c pointer to another one; 1208 // as in I* to id. 1209 if (FromPointeeType->getAs<ObjCObjectPointerType>() && 1210 ToPointeeType->getAs<ObjCObjectPointerType>() && 1211 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1212 IncompatibleObjC)) { 1213 ConvertedType = ToType; 1214 return true; 1215 } 1216 1217 // If we have pointers to functions or blocks, check whether the only 1218 // differences in the argument and result types are in Objective-C 1219 // pointer conversions. If so, we permit the conversion (but 1220 // complain about it). 1221 const FunctionProtoType *FromFunctionType 1222 = FromPointeeType->getAs<FunctionProtoType>(); 1223 const FunctionProtoType *ToFunctionType 1224 = ToPointeeType->getAs<FunctionProtoType>(); 1225 if (FromFunctionType && ToFunctionType) { 1226 // If the function types are exactly the same, this isn't an 1227 // Objective-C pointer conversion. 1228 if (Context.getCanonicalType(FromPointeeType) 1229 == Context.getCanonicalType(ToPointeeType)) 1230 return false; 1231 1232 // Perform the quick checks that will tell us whether these 1233 // function types are obviously different. 1234 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1235 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1236 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1237 return false; 1238 1239 bool HasObjCConversion = false; 1240 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1241 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1242 // Okay, the types match exactly. Nothing to do. 1243 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1244 ToFunctionType->getResultType(), 1245 ConvertedType, IncompatibleObjC)) { 1246 // Okay, we have an Objective-C pointer conversion. 1247 HasObjCConversion = true; 1248 } else { 1249 // Function types are too different. Abort. 1250 return false; 1251 } 1252 1253 // Check argument types. 1254 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1255 ArgIdx != NumArgs; ++ArgIdx) { 1256 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1257 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1258 if (Context.getCanonicalType(FromArgType) 1259 == Context.getCanonicalType(ToArgType)) { 1260 // Okay, the types match exactly. Nothing to do. 1261 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1262 ConvertedType, IncompatibleObjC)) { 1263 // Okay, we have an Objective-C pointer conversion. 1264 HasObjCConversion = true; 1265 } else { 1266 // Argument types are too different. Abort. 1267 return false; 1268 } 1269 } 1270 1271 if (HasObjCConversion) { 1272 // We had an Objective-C conversion. Allow this pointer 1273 // conversion, but complain about it. 1274 ConvertedType = ToType; 1275 IncompatibleObjC = true; 1276 return true; 1277 } 1278 } 1279 1280 return false; 1281} 1282 1283/// CheckPointerConversion - Check the pointer conversion from the 1284/// expression From to the type ToType. This routine checks for 1285/// ambiguous or inaccessible derived-to-base pointer 1286/// conversions for which IsPointerConversion has already returned 1287/// true. It returns true and produces a diagnostic if there was an 1288/// error, or returns false otherwise. 1289bool Sema::CheckPointerConversion(Expr *From, QualType ToType, 1290 CastExpr::CastKind &Kind, 1291 bool IgnoreBaseAccess) { 1292 QualType FromType = From->getType(); 1293 1294 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) 1295 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { 1296 QualType FromPointeeType = FromPtrType->getPointeeType(), 1297 ToPointeeType = ToPtrType->getPointeeType(); 1298 1299 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1300 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) { 1301 // We must have a derived-to-base conversion. Check an 1302 // ambiguous or inaccessible conversion. 1303 if (CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1304 From->getExprLoc(), 1305 From->getSourceRange(), 1306 IgnoreBaseAccess)) 1307 return true; 1308 1309 // The conversion was successful. 1310 Kind = CastExpr::CK_DerivedToBase; 1311 } 1312 } 1313 if (const ObjCObjectPointerType *FromPtrType = 1314 FromType->getAs<ObjCObjectPointerType>()) 1315 if (const ObjCObjectPointerType *ToPtrType = 1316 ToType->getAs<ObjCObjectPointerType>()) { 1317 // Objective-C++ conversions are always okay. 1318 // FIXME: We should have a different class of conversions for the 1319 // Objective-C++ implicit conversions. 1320 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) 1321 return false; 1322 1323 } 1324 return false; 1325} 1326 1327/// IsMemberPointerConversion - Determines whether the conversion of the 1328/// expression From, which has the (possibly adjusted) type FromType, can be 1329/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1330/// If so, returns true and places the converted type (that might differ from 1331/// ToType in its cv-qualifiers at some level) into ConvertedType. 1332bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1333 QualType ToType, 1334 bool InOverloadResolution, 1335 QualType &ConvertedType) { 1336 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>(); 1337 if (!ToTypePtr) 1338 return false; 1339 1340 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1341 if (From->isNullPointerConstant(Context, 1342 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1343 : Expr::NPC_ValueDependentIsNull)) { 1344 ConvertedType = ToType; 1345 return true; 1346 } 1347 1348 // Otherwise, both types have to be member pointers. 1349 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>(); 1350 if (!FromTypePtr) 1351 return false; 1352 1353 // A pointer to member of B can be converted to a pointer to member of D, 1354 // where D is derived from B (C++ 4.11p2). 1355 QualType FromClass(FromTypePtr->getClass(), 0); 1356 QualType ToClass(ToTypePtr->getClass(), 0); 1357 // FIXME: What happens when these are dependent? Is this function even called? 1358 1359 if (IsDerivedFrom(ToClass, FromClass)) { 1360 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1361 ToClass.getTypePtr()); 1362 return true; 1363 } 1364 1365 return false; 1366} 1367 1368/// CheckMemberPointerConversion - Check the member pointer conversion from the 1369/// expression From to the type ToType. This routine checks for ambiguous or 1370/// virtual or inaccessible base-to-derived member pointer conversions 1371/// for which IsMemberPointerConversion has already returned true. It returns 1372/// true and produces a diagnostic if there was an error, or returns false 1373/// otherwise. 1374bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, 1375 CastExpr::CastKind &Kind, 1376 bool IgnoreBaseAccess) { 1377 QualType FromType = From->getType(); 1378 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); 1379 if (!FromPtrType) { 1380 // This must be a null pointer to member pointer conversion 1381 assert(From->isNullPointerConstant(Context, 1382 Expr::NPC_ValueDependentIsNull) && 1383 "Expr must be null pointer constant!"); 1384 Kind = CastExpr::CK_NullToMemberPointer; 1385 return false; 1386 } 1387 1388 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>(); 1389 assert(ToPtrType && "No member pointer cast has a target type " 1390 "that is not a member pointer."); 1391 1392 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1393 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1394 1395 // FIXME: What about dependent types? 1396 assert(FromClass->isRecordType() && "Pointer into non-class."); 1397 assert(ToClass->isRecordType() && "Pointer into non-class."); 1398 1399 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/ true, 1400 /*DetectVirtual=*/true); 1401 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1402 assert(DerivationOkay && 1403 "Should not have been called if derivation isn't OK."); 1404 (void)DerivationOkay; 1405 1406 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1407 getUnqualifiedType())) { 1408 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1409 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1410 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1411 return true; 1412 } 1413 1414 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1415 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1416 << FromClass << ToClass << QualType(VBase, 0) 1417 << From->getSourceRange(); 1418 return true; 1419 } 1420 1421 if (!IgnoreBaseAccess) 1422 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass, 1423 Paths.front(), 1424 diag::err_downcast_from_inaccessible_base); 1425 1426 // Must be a base to derived member conversion. 1427 Kind = CastExpr::CK_BaseToDerivedMemberPointer; 1428 return false; 1429} 1430 1431/// IsQualificationConversion - Determines whether the conversion from 1432/// an rvalue of type FromType to ToType is a qualification conversion 1433/// (C++ 4.4). 1434bool 1435Sema::IsQualificationConversion(QualType FromType, QualType ToType) { 1436 FromType = Context.getCanonicalType(FromType); 1437 ToType = Context.getCanonicalType(ToType); 1438 1439 // If FromType and ToType are the same type, this is not a 1440 // qualification conversion. 1441 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType()) 1442 return false; 1443 1444 // (C++ 4.4p4): 1445 // A conversion can add cv-qualifiers at levels other than the first 1446 // in multi-level pointers, subject to the following rules: [...] 1447 bool PreviousToQualsIncludeConst = true; 1448 bool UnwrappedAnyPointer = false; 1449 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1450 // Within each iteration of the loop, we check the qualifiers to 1451 // determine if this still looks like a qualification 1452 // conversion. Then, if all is well, we unwrap one more level of 1453 // pointers or pointers-to-members and do it all again 1454 // until there are no more pointers or pointers-to-members left to 1455 // unwrap. 1456 UnwrappedAnyPointer = true; 1457 1458 // -- for every j > 0, if const is in cv 1,j then const is in cv 1459 // 2,j, and similarly for volatile. 1460 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1461 return false; 1462 1463 // -- if the cv 1,j and cv 2,j are different, then const is in 1464 // every cv for 0 < k < j. 1465 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1466 && !PreviousToQualsIncludeConst) 1467 return false; 1468 1469 // Keep track of whether all prior cv-qualifiers in the "to" type 1470 // include const. 1471 PreviousToQualsIncludeConst 1472 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1473 } 1474 1475 // We are left with FromType and ToType being the pointee types 1476 // after unwrapping the original FromType and ToType the same number 1477 // of types. If we unwrapped any pointers, and if FromType and 1478 // ToType have the same unqualified type (since we checked 1479 // qualifiers above), then this is a qualification conversion. 1480 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); 1481} 1482 1483/// Determines whether there is a user-defined conversion sequence 1484/// (C++ [over.ics.user]) that converts expression From to the type 1485/// ToType. If such a conversion exists, User will contain the 1486/// user-defined conversion sequence that performs such a conversion 1487/// and this routine will return true. Otherwise, this routine returns 1488/// false and User is unspecified. 1489/// 1490/// \param AllowConversionFunctions true if the conversion should 1491/// consider conversion functions at all. If false, only constructors 1492/// will be considered. 1493/// 1494/// \param AllowExplicit true if the conversion should consider C++0x 1495/// "explicit" conversion functions as well as non-explicit conversion 1496/// functions (C++0x [class.conv.fct]p2). 1497/// 1498/// \param UserCast true if looking for user defined conversion for a static 1499/// cast. 1500OverloadingResult Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1501 UserDefinedConversionSequence& User, 1502 OverloadCandidateSet& CandidateSet, 1503 bool AllowConversionFunctions, 1504 bool AllowExplicit, 1505 bool UserCast) { 1506 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { 1507 if (RequireCompleteType(From->getLocStart(), ToType, PDiag())) { 1508 // We're not going to find any constructors. 1509 } else if (CXXRecordDecl *ToRecordDecl 1510 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1511 // C++ [over.match.ctor]p1: 1512 // When objects of class type are direct-initialized (8.5), or 1513 // copy-initialized from an expression of the same or a 1514 // derived class type (8.5), overload resolution selects the 1515 // constructor. [...] For copy-initialization, the candidate 1516 // functions are all the converting constructors (12.3.1) of 1517 // that class. The argument list is the expression-list within 1518 // the parentheses of the initializer. 1519 bool SuppressUserConversions = !UserCast; 1520 if (Context.hasSameUnqualifiedType(ToType, From->getType()) || 1521 IsDerivedFrom(From->getType(), ToType)) { 1522 SuppressUserConversions = false; 1523 AllowConversionFunctions = false; 1524 } 1525 1526 DeclarationName ConstructorName 1527 = Context.DeclarationNames.getCXXConstructorName( 1528 Context.getCanonicalType(ToType).getUnqualifiedType()); 1529 DeclContext::lookup_iterator Con, ConEnd; 1530 for (llvm::tie(Con, ConEnd) 1531 = ToRecordDecl->lookup(ConstructorName); 1532 Con != ConEnd; ++Con) { 1533 NamedDecl *D = *Con; 1534 DeclAccessPair FoundDecl = DeclAccessPair::make(D, D->getAccess()); 1535 1536 // Find the constructor (which may be a template). 1537 CXXConstructorDecl *Constructor = 0; 1538 FunctionTemplateDecl *ConstructorTmpl 1539 = dyn_cast<FunctionTemplateDecl>(D); 1540 if (ConstructorTmpl) 1541 Constructor 1542 = cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl()); 1543 else 1544 Constructor = cast<CXXConstructorDecl>(D); 1545 1546 if (!Constructor->isInvalidDecl() && 1547 Constructor->isConvertingConstructor(AllowExplicit)) { 1548 if (ConstructorTmpl) 1549 AddTemplateOverloadCandidate(ConstructorTmpl, FoundDecl, 1550 /*ExplicitArgs*/ 0, 1551 &From, 1, CandidateSet, 1552 SuppressUserConversions, false); 1553 else 1554 // Allow one user-defined conversion when user specifies a 1555 // From->ToType conversion via an static cast (c-style, etc). 1556 AddOverloadCandidate(Constructor, FoundDecl, 1557 &From, 1, CandidateSet, 1558 SuppressUserConversions, false); 1559 } 1560 } 1561 } 1562 } 1563 1564 if (!AllowConversionFunctions) { 1565 // Don't allow any conversion functions to enter the overload set. 1566 } else if (RequireCompleteType(From->getLocStart(), From->getType(), 1567 PDiag(0) 1568 << From->getSourceRange())) { 1569 // No conversion functions from incomplete types. 1570 } else if (const RecordType *FromRecordType 1571 = From->getType()->getAs<RecordType>()) { 1572 if (CXXRecordDecl *FromRecordDecl 1573 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1574 // Add all of the conversion functions as candidates. 1575 const UnresolvedSetImpl *Conversions 1576 = FromRecordDecl->getVisibleConversionFunctions(); 1577 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 1578 E = Conversions->end(); I != E; ++I) { 1579 DeclAccessPair FoundDecl = I.getPair(); 1580 NamedDecl *D = FoundDecl.getDecl(); 1581 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 1582 if (isa<UsingShadowDecl>(D)) 1583 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 1584 1585 CXXConversionDecl *Conv; 1586 FunctionTemplateDecl *ConvTemplate; 1587 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D))) 1588 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 1589 else 1590 Conv = cast<CXXConversionDecl>(D); 1591 1592 if (AllowExplicit || !Conv->isExplicit()) { 1593 if (ConvTemplate) 1594 AddTemplateConversionCandidate(ConvTemplate, FoundDecl, 1595 ActingContext, From, ToType, 1596 CandidateSet); 1597 else 1598 AddConversionCandidate(Conv, FoundDecl, ActingContext, 1599 From, ToType, CandidateSet); 1600 } 1601 } 1602 } 1603 } 1604 1605 OverloadCandidateSet::iterator Best; 1606 switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) { 1607 case OR_Success: 1608 // Record the standard conversion we used and the conversion function. 1609 if (CXXConstructorDecl *Constructor 1610 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1611 // C++ [over.ics.user]p1: 1612 // If the user-defined conversion is specified by a 1613 // constructor (12.3.1), the initial standard conversion 1614 // sequence converts the source type to the type required by 1615 // the argument of the constructor. 1616 // 1617 QualType ThisType = Constructor->getThisType(Context); 1618 if (Best->Conversions[0].isEllipsis()) 1619 User.EllipsisConversion = true; 1620 else { 1621 User.Before = Best->Conversions[0].Standard; 1622 User.EllipsisConversion = false; 1623 } 1624 User.ConversionFunction = Constructor; 1625 User.After.setAsIdentityConversion(); 1626 User.After.setFromType( 1627 ThisType->getAs<PointerType>()->getPointeeType()); 1628 User.After.setAllToTypes(ToType); 1629 return OR_Success; 1630 } else if (CXXConversionDecl *Conversion 1631 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1632 // C++ [over.ics.user]p1: 1633 // 1634 // [...] If the user-defined conversion is specified by a 1635 // conversion function (12.3.2), the initial standard 1636 // conversion sequence converts the source type to the 1637 // implicit object parameter of the conversion function. 1638 User.Before = Best->Conversions[0].Standard; 1639 User.ConversionFunction = Conversion; 1640 User.EllipsisConversion = false; 1641 1642 // C++ [over.ics.user]p2: 1643 // The second standard conversion sequence converts the 1644 // result of the user-defined conversion to the target type 1645 // for the sequence. Since an implicit conversion sequence 1646 // is an initialization, the special rules for 1647 // initialization by user-defined conversion apply when 1648 // selecting the best user-defined conversion for a 1649 // user-defined conversion sequence (see 13.3.3 and 1650 // 13.3.3.1). 1651 User.After = Best->FinalConversion; 1652 return OR_Success; 1653 } else { 1654 assert(false && "Not a constructor or conversion function?"); 1655 return OR_No_Viable_Function; 1656 } 1657 1658 case OR_No_Viable_Function: 1659 return OR_No_Viable_Function; 1660 case OR_Deleted: 1661 // No conversion here! We're done. 1662 return OR_Deleted; 1663 1664 case OR_Ambiguous: 1665 return OR_Ambiguous; 1666 } 1667 1668 return OR_No_Viable_Function; 1669} 1670 1671bool 1672Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { 1673 ImplicitConversionSequence ICS; 1674 OverloadCandidateSet CandidateSet(From->getExprLoc()); 1675 OverloadingResult OvResult = 1676 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 1677 CandidateSet, true, false, false); 1678 if (OvResult == OR_Ambiguous) 1679 Diag(From->getSourceRange().getBegin(), 1680 diag::err_typecheck_ambiguous_condition) 1681 << From->getType() << ToType << From->getSourceRange(); 1682 else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) 1683 Diag(From->getSourceRange().getBegin(), 1684 diag::err_typecheck_nonviable_condition) 1685 << From->getType() << ToType << From->getSourceRange(); 1686 else 1687 return false; 1688 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &From, 1); 1689 return true; 1690} 1691 1692/// CompareImplicitConversionSequences - Compare two implicit 1693/// conversion sequences to determine whether one is better than the 1694/// other or if they are indistinguishable (C++ 13.3.3.2). 1695ImplicitConversionSequence::CompareKind 1696Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1697 const ImplicitConversionSequence& ICS2) 1698{ 1699 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1700 // conversion sequences (as defined in 13.3.3.1) 1701 // -- a standard conversion sequence (13.3.3.1.1) is a better 1702 // conversion sequence than a user-defined conversion sequence or 1703 // an ellipsis conversion sequence, and 1704 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1705 // conversion sequence than an ellipsis conversion sequence 1706 // (13.3.3.1.3). 1707 // 1708 // C++0x [over.best.ics]p10: 1709 // For the purpose of ranking implicit conversion sequences as 1710 // described in 13.3.3.2, the ambiguous conversion sequence is 1711 // treated as a user-defined sequence that is indistinguishable 1712 // from any other user-defined conversion sequence. 1713 if (ICS1.getKind() < ICS2.getKind()) { 1714 if (!(ICS1.isUserDefined() && ICS2.isAmbiguous())) 1715 return ImplicitConversionSequence::Better; 1716 } else if (ICS2.getKind() < ICS1.getKind()) { 1717 if (!(ICS2.isUserDefined() && ICS1.isAmbiguous())) 1718 return ImplicitConversionSequence::Worse; 1719 } 1720 1721 if (ICS1.isAmbiguous() || ICS2.isAmbiguous()) 1722 return ImplicitConversionSequence::Indistinguishable; 1723 1724 // Two implicit conversion sequences of the same form are 1725 // indistinguishable conversion sequences unless one of the 1726 // following rules apply: (C++ 13.3.3.2p3): 1727 if (ICS1.isStandard()) 1728 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1729 else if (ICS1.isUserDefined()) { 1730 // User-defined conversion sequence U1 is a better conversion 1731 // sequence than another user-defined conversion sequence U2 if 1732 // they contain the same user-defined conversion function or 1733 // constructor and if the second standard conversion sequence of 1734 // U1 is better than the second standard conversion sequence of 1735 // U2 (C++ 13.3.3.2p3). 1736 if (ICS1.UserDefined.ConversionFunction == 1737 ICS2.UserDefined.ConversionFunction) 1738 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1739 ICS2.UserDefined.After); 1740 } 1741 1742 return ImplicitConversionSequence::Indistinguishable; 1743} 1744 1745// Per 13.3.3.2p3, compare the given standard conversion sequences to 1746// determine if one is a proper subset of the other. 1747static ImplicitConversionSequence::CompareKind 1748compareStandardConversionSubsets(ASTContext &Context, 1749 const StandardConversionSequence& SCS1, 1750 const StandardConversionSequence& SCS2) { 1751 ImplicitConversionSequence::CompareKind Result 1752 = ImplicitConversionSequence::Indistinguishable; 1753 1754 if (SCS1.Second != SCS2.Second) { 1755 if (SCS1.Second == ICK_Identity) 1756 Result = ImplicitConversionSequence::Better; 1757 else if (SCS2.Second == ICK_Identity) 1758 Result = ImplicitConversionSequence::Worse; 1759 else 1760 return ImplicitConversionSequence::Indistinguishable; 1761 } else if (!Context.hasSameType(SCS1.getToType(1), SCS2.getToType(1))) 1762 return ImplicitConversionSequence::Indistinguishable; 1763 1764 if (SCS1.Third == SCS2.Third) { 1765 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result 1766 : ImplicitConversionSequence::Indistinguishable; 1767 } 1768 1769 if (SCS1.Third == ICK_Identity) 1770 return Result == ImplicitConversionSequence::Worse 1771 ? ImplicitConversionSequence::Indistinguishable 1772 : ImplicitConversionSequence::Better; 1773 1774 if (SCS2.Third == ICK_Identity) 1775 return Result == ImplicitConversionSequence::Better 1776 ? ImplicitConversionSequence::Indistinguishable 1777 : ImplicitConversionSequence::Worse; 1778 1779 return ImplicitConversionSequence::Indistinguishable; 1780} 1781 1782/// CompareStandardConversionSequences - Compare two standard 1783/// conversion sequences to determine whether one is better than the 1784/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1785ImplicitConversionSequence::CompareKind 1786Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1787 const StandardConversionSequence& SCS2) 1788{ 1789 // Standard conversion sequence S1 is a better conversion sequence 1790 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1791 1792 // -- S1 is a proper subsequence of S2 (comparing the conversion 1793 // sequences in the canonical form defined by 13.3.3.1.1, 1794 // excluding any Lvalue Transformation; the identity conversion 1795 // sequence is considered to be a subsequence of any 1796 // non-identity conversion sequence) or, if not that, 1797 if (ImplicitConversionSequence::CompareKind CK 1798 = compareStandardConversionSubsets(Context, SCS1, SCS2)) 1799 return CK; 1800 1801 // -- the rank of S1 is better than the rank of S2 (by the rules 1802 // defined below), or, if not that, 1803 ImplicitConversionRank Rank1 = SCS1.getRank(); 1804 ImplicitConversionRank Rank2 = SCS2.getRank(); 1805 if (Rank1 < Rank2) 1806 return ImplicitConversionSequence::Better; 1807 else if (Rank2 < Rank1) 1808 return ImplicitConversionSequence::Worse; 1809 1810 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1811 // are indistinguishable unless one of the following rules 1812 // applies: 1813 1814 // A conversion that is not a conversion of a pointer, or 1815 // pointer to member, to bool is better than another conversion 1816 // that is such a conversion. 1817 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1818 return SCS2.isPointerConversionToBool() 1819 ? ImplicitConversionSequence::Better 1820 : ImplicitConversionSequence::Worse; 1821 1822 // C++ [over.ics.rank]p4b2: 1823 // 1824 // If class B is derived directly or indirectly from class A, 1825 // conversion of B* to A* is better than conversion of B* to 1826 // void*, and conversion of A* to void* is better than conversion 1827 // of B* to void*. 1828 bool SCS1ConvertsToVoid 1829 = SCS1.isPointerConversionToVoidPointer(Context); 1830 bool SCS2ConvertsToVoid 1831 = SCS2.isPointerConversionToVoidPointer(Context); 1832 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1833 // Exactly one of the conversion sequences is a conversion to 1834 // a void pointer; it's the worse conversion. 1835 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1836 : ImplicitConversionSequence::Worse; 1837 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1838 // Neither conversion sequence converts to a void pointer; compare 1839 // their derived-to-base conversions. 1840 if (ImplicitConversionSequence::CompareKind DerivedCK 1841 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1842 return DerivedCK; 1843 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1844 // Both conversion sequences are conversions to void 1845 // pointers. Compare the source types to determine if there's an 1846 // inheritance relationship in their sources. 1847 QualType FromType1 = SCS1.getFromType(); 1848 QualType FromType2 = SCS2.getFromType(); 1849 1850 // Adjust the types we're converting from via the array-to-pointer 1851 // conversion, if we need to. 1852 if (SCS1.First == ICK_Array_To_Pointer) 1853 FromType1 = Context.getArrayDecayedType(FromType1); 1854 if (SCS2.First == ICK_Array_To_Pointer) 1855 FromType2 = Context.getArrayDecayedType(FromType2); 1856 1857 QualType FromPointee1 1858 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1859 QualType FromPointee2 1860 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1861 1862 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1863 return ImplicitConversionSequence::Better; 1864 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1865 return ImplicitConversionSequence::Worse; 1866 1867 // Objective-C++: If one interface is more specific than the 1868 // other, it is the better one. 1869 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 1870 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 1871 if (FromIface1 && FromIface1) { 1872 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1873 return ImplicitConversionSequence::Better; 1874 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1875 return ImplicitConversionSequence::Worse; 1876 } 1877 } 1878 1879 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1880 // bullet 3). 1881 if (ImplicitConversionSequence::CompareKind QualCK 1882 = CompareQualificationConversions(SCS1, SCS2)) 1883 return QualCK; 1884 1885 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1886 // C++0x [over.ics.rank]p3b4: 1887 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 1888 // implicit object parameter of a non-static member function declared 1889 // without a ref-qualifier, and S1 binds an rvalue reference to an 1890 // rvalue and S2 binds an lvalue reference. 1891 // FIXME: We don't know if we're dealing with the implicit object parameter, 1892 // or if the member function in this case has a ref qualifier. 1893 // (Of course, we don't have ref qualifiers yet.) 1894 if (SCS1.RRefBinding != SCS2.RRefBinding) 1895 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 1896 : ImplicitConversionSequence::Worse; 1897 1898 // C++ [over.ics.rank]p3b4: 1899 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1900 // which the references refer are the same type except for 1901 // top-level cv-qualifiers, and the type to which the reference 1902 // initialized by S2 refers is more cv-qualified than the type 1903 // to which the reference initialized by S1 refers. 1904 QualType T1 = SCS1.getToType(2); 1905 QualType T2 = SCS2.getToType(2); 1906 T1 = Context.getCanonicalType(T1); 1907 T2 = Context.getCanonicalType(T2); 1908 Qualifiers T1Quals, T2Quals; 1909 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1910 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1911 if (UnqualT1 == UnqualT2) { 1912 // If the type is an array type, promote the element qualifiers to the type 1913 // for comparison. 1914 if (isa<ArrayType>(T1) && T1Quals) 1915 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 1916 if (isa<ArrayType>(T2) && T2Quals) 1917 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 1918 if (T2.isMoreQualifiedThan(T1)) 1919 return ImplicitConversionSequence::Better; 1920 else if (T1.isMoreQualifiedThan(T2)) 1921 return ImplicitConversionSequence::Worse; 1922 } 1923 } 1924 1925 return ImplicitConversionSequence::Indistinguishable; 1926} 1927 1928/// CompareQualificationConversions - Compares two standard conversion 1929/// sequences to determine whether they can be ranked based on their 1930/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1931ImplicitConversionSequence::CompareKind 1932Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1933 const StandardConversionSequence& SCS2) { 1934 // C++ 13.3.3.2p3: 1935 // -- S1 and S2 differ only in their qualification conversion and 1936 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1937 // cv-qualification signature of type T1 is a proper subset of 1938 // the cv-qualification signature of type T2, and S1 is not the 1939 // deprecated string literal array-to-pointer conversion (4.2). 1940 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1941 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1942 return ImplicitConversionSequence::Indistinguishable; 1943 1944 // FIXME: the example in the standard doesn't use a qualification 1945 // conversion (!) 1946 QualType T1 = SCS1.getToType(2); 1947 QualType T2 = SCS2.getToType(2); 1948 T1 = Context.getCanonicalType(T1); 1949 T2 = Context.getCanonicalType(T2); 1950 Qualifiers T1Quals, T2Quals; 1951 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1952 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1953 1954 // If the types are the same, we won't learn anything by unwrapped 1955 // them. 1956 if (UnqualT1 == UnqualT2) 1957 return ImplicitConversionSequence::Indistinguishable; 1958 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 1966 ImplicitConversionSequence::CompareKind Result 1967 = ImplicitConversionSequence::Indistinguishable; 1968 while (UnwrapSimilarPointerTypes(T1, T2)) { 1969 // Within each iteration of the loop, we check the qualifiers to 1970 // determine if this still looks like a qualification 1971 // conversion. Then, if all is well, we unwrap one more level of 1972 // pointers or pointers-to-members and do it all again 1973 // until there are no more pointers or pointers-to-members left 1974 // to unwrap. This essentially mimics what 1975 // IsQualificationConversion does, but here we're checking for a 1976 // strict subset of qualifiers. 1977 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1978 // The qualifiers are the same, so this doesn't tell us anything 1979 // about how the sequences rank. 1980 ; 1981 else if (T2.isMoreQualifiedThan(T1)) { 1982 // T1 has fewer qualifiers, so it could be the better sequence. 1983 if (Result == ImplicitConversionSequence::Worse) 1984 // Neither has qualifiers that are a subset of the other's 1985 // qualifiers. 1986 return ImplicitConversionSequence::Indistinguishable; 1987 1988 Result = ImplicitConversionSequence::Better; 1989 } else if (T1.isMoreQualifiedThan(T2)) { 1990 // T2 has fewer qualifiers, so it could be the better sequence. 1991 if (Result == ImplicitConversionSequence::Better) 1992 // Neither has qualifiers that are a subset of the other's 1993 // qualifiers. 1994 return ImplicitConversionSequence::Indistinguishable; 1995 1996 Result = ImplicitConversionSequence::Worse; 1997 } else { 1998 // Qualifiers are disjoint. 1999 return ImplicitConversionSequence::Indistinguishable; 2000 } 2001 2002 // If the types after this point are equivalent, we're done. 2003 if (Context.hasSameUnqualifiedType(T1, T2)) 2004 break; 2005 } 2006 2007 // Check that the winning standard conversion sequence isn't using 2008 // the deprecated string literal array to pointer conversion. 2009 switch (Result) { 2010 case ImplicitConversionSequence::Better: 2011 if (SCS1.DeprecatedStringLiteralToCharPtr) 2012 Result = ImplicitConversionSequence::Indistinguishable; 2013 break; 2014 2015 case ImplicitConversionSequence::Indistinguishable: 2016 break; 2017 2018 case ImplicitConversionSequence::Worse: 2019 if (SCS2.DeprecatedStringLiteralToCharPtr) 2020 Result = ImplicitConversionSequence::Indistinguishable; 2021 break; 2022 } 2023 2024 return Result; 2025} 2026 2027/// CompareDerivedToBaseConversions - Compares two standard conversion 2028/// sequences to determine whether they can be ranked based on their 2029/// various kinds of derived-to-base conversions (C++ 2030/// [over.ics.rank]p4b3). As part of these checks, we also look at 2031/// conversions between Objective-C interface types. 2032ImplicitConversionSequence::CompareKind 2033Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 2034 const StandardConversionSequence& SCS2) { 2035 QualType FromType1 = SCS1.getFromType(); 2036 QualType ToType1 = SCS1.getToType(1); 2037 QualType FromType2 = SCS2.getFromType(); 2038 QualType ToType2 = SCS2.getToType(1); 2039 2040 // Adjust the types we're converting from via the array-to-pointer 2041 // conversion, if we need to. 2042 if (SCS1.First == ICK_Array_To_Pointer) 2043 FromType1 = Context.getArrayDecayedType(FromType1); 2044 if (SCS2.First == ICK_Array_To_Pointer) 2045 FromType2 = Context.getArrayDecayedType(FromType2); 2046 2047 // Canonicalize all of the types. 2048 FromType1 = Context.getCanonicalType(FromType1); 2049 ToType1 = Context.getCanonicalType(ToType1); 2050 FromType2 = Context.getCanonicalType(FromType2); 2051 ToType2 = Context.getCanonicalType(ToType2); 2052 2053 // C++ [over.ics.rank]p4b3: 2054 // 2055 // If class B is derived directly or indirectly from class A and 2056 // class C is derived directly or indirectly from B, 2057 // 2058 // For Objective-C, we let A, B, and C also be Objective-C 2059 // interfaces. 2060 2061 // Compare based on pointer conversions. 2062 if (SCS1.Second == ICK_Pointer_Conversion && 2063 SCS2.Second == ICK_Pointer_Conversion && 2064 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 2065 FromType1->isPointerType() && FromType2->isPointerType() && 2066 ToType1->isPointerType() && ToType2->isPointerType()) { 2067 QualType FromPointee1 2068 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2069 QualType ToPointee1 2070 = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2071 QualType FromPointee2 2072 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2073 QualType ToPointee2 2074 = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 2075 2076 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 2077 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 2078 const ObjCInterfaceType* ToIface1 = ToPointee1->getAs<ObjCInterfaceType>(); 2079 const ObjCInterfaceType* ToIface2 = ToPointee2->getAs<ObjCInterfaceType>(); 2080 2081 // -- conversion of C* to B* is better than conversion of C* to A*, 2082 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2083 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2084 return ImplicitConversionSequence::Better; 2085 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2086 return ImplicitConversionSequence::Worse; 2087 2088 if (ToIface1 && ToIface2) { 2089 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 2090 return ImplicitConversionSequence::Better; 2091 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 2092 return ImplicitConversionSequence::Worse; 2093 } 2094 } 2095 2096 // -- conversion of B* to A* is better than conversion of C* to A*, 2097 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 2098 if (IsDerivedFrom(FromPointee2, FromPointee1)) 2099 return ImplicitConversionSequence::Better; 2100 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 2101 return ImplicitConversionSequence::Worse; 2102 2103 if (FromIface1 && FromIface2) { 2104 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2105 return ImplicitConversionSequence::Better; 2106 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2107 return ImplicitConversionSequence::Worse; 2108 } 2109 } 2110 } 2111 2112 // Ranking of member-pointer types. 2113 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && 2114 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && 2115 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { 2116 const MemberPointerType * FromMemPointer1 = 2117 FromType1->getAs<MemberPointerType>(); 2118 const MemberPointerType * ToMemPointer1 = 2119 ToType1->getAs<MemberPointerType>(); 2120 const MemberPointerType * FromMemPointer2 = 2121 FromType2->getAs<MemberPointerType>(); 2122 const MemberPointerType * ToMemPointer2 = 2123 ToType2->getAs<MemberPointerType>(); 2124 const Type *FromPointeeType1 = FromMemPointer1->getClass(); 2125 const Type *ToPointeeType1 = ToMemPointer1->getClass(); 2126 const Type *FromPointeeType2 = FromMemPointer2->getClass(); 2127 const Type *ToPointeeType2 = ToMemPointer2->getClass(); 2128 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); 2129 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); 2130 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); 2131 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); 2132 // conversion of A::* to B::* is better than conversion of A::* to C::*, 2133 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2134 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2135 return ImplicitConversionSequence::Worse; 2136 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2137 return ImplicitConversionSequence::Better; 2138 } 2139 // conversion of B::* to C::* is better than conversion of A::* to C::* 2140 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { 2141 if (IsDerivedFrom(FromPointee1, FromPointee2)) 2142 return ImplicitConversionSequence::Better; 2143 else if (IsDerivedFrom(FromPointee2, FromPointee1)) 2144 return ImplicitConversionSequence::Worse; 2145 } 2146 } 2147 2148 if ((SCS1.ReferenceBinding || SCS1.CopyConstructor) && 2149 (SCS2.ReferenceBinding || SCS2.CopyConstructor) && 2150 SCS1.Second == ICK_Derived_To_Base) { 2151 // -- conversion of C to B is better than conversion of C to A, 2152 // -- binding of an expression of type C to a reference of type 2153 // B& is better than binding an expression of type C to a 2154 // reference of type A&, 2155 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2156 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2157 if (IsDerivedFrom(ToType1, ToType2)) 2158 return ImplicitConversionSequence::Better; 2159 else if (IsDerivedFrom(ToType2, ToType1)) 2160 return ImplicitConversionSequence::Worse; 2161 } 2162 2163 // -- conversion of B to A is better than conversion of C to A. 2164 // -- binding of an expression of type B to a reference of type 2165 // A& is better than binding an expression of type C to a 2166 // reference of type A&, 2167 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2168 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2169 if (IsDerivedFrom(FromType2, FromType1)) 2170 return ImplicitConversionSequence::Better; 2171 else if (IsDerivedFrom(FromType1, FromType2)) 2172 return ImplicitConversionSequence::Worse; 2173 } 2174 } 2175 2176 return ImplicitConversionSequence::Indistinguishable; 2177} 2178 2179/// CompareReferenceRelationship - Compare the two types T1 and T2 to 2180/// determine whether they are reference-related, 2181/// reference-compatible, reference-compatible with added 2182/// qualification, or incompatible, for use in C++ initialization by 2183/// reference (C++ [dcl.ref.init]p4). Neither type can be a reference 2184/// type, and the first type (T1) is the pointee type of the reference 2185/// type being initialized. 2186Sema::ReferenceCompareResult 2187Sema::CompareReferenceRelationship(SourceLocation Loc, 2188 QualType OrigT1, QualType OrigT2, 2189 bool& DerivedToBase) { 2190 assert(!OrigT1->isReferenceType() && 2191 "T1 must be the pointee type of the reference type"); 2192 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type"); 2193 2194 QualType T1 = Context.getCanonicalType(OrigT1); 2195 QualType T2 = Context.getCanonicalType(OrigT2); 2196 Qualifiers T1Quals, T2Quals; 2197 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 2198 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 2199 2200 // C++ [dcl.init.ref]p4: 2201 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is 2202 // reference-related to "cv2 T2" if T1 is the same type as T2, or 2203 // T1 is a base class of T2. 2204 if (UnqualT1 == UnqualT2) 2205 DerivedToBase = false; 2206 else if (!RequireCompleteType(Loc, OrigT1, PDiag()) && 2207 !RequireCompleteType(Loc, OrigT2, PDiag()) && 2208 IsDerivedFrom(UnqualT2, UnqualT1)) 2209 DerivedToBase = true; 2210 else 2211 return Ref_Incompatible; 2212 2213 // At this point, we know that T1 and T2 are reference-related (at 2214 // least). 2215 2216 // If the type is an array type, promote the element qualifiers to the type 2217 // for comparison. 2218 if (isa<ArrayType>(T1) && T1Quals) 2219 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 2220 if (isa<ArrayType>(T2) && T2Quals) 2221 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 2222 2223 // C++ [dcl.init.ref]p4: 2224 // "cv1 T1" is reference-compatible with "cv2 T2" if T1 is 2225 // reference-related to T2 and cv1 is the same cv-qualification 2226 // as, or greater cv-qualification than, cv2. For purposes of 2227 // overload resolution, cases for which cv1 is greater 2228 // cv-qualification than cv2 are identified as 2229 // reference-compatible with added qualification (see 13.3.3.2). 2230 if (T1Quals.getCVRQualifiers() == T2Quals.getCVRQualifiers()) 2231 return Ref_Compatible; 2232 else if (T1.isMoreQualifiedThan(T2)) 2233 return Ref_Compatible_With_Added_Qualification; 2234 else 2235 return Ref_Related; 2236} 2237 2238/// \brief Compute an implicit conversion sequence for reference 2239/// initialization. 2240static ImplicitConversionSequence 2241TryReferenceInit(Sema &S, Expr *&Init, QualType DeclType, 2242 SourceLocation DeclLoc, 2243 bool SuppressUserConversions, 2244 bool AllowExplicit, bool ForceRValue) { 2245 assert(DeclType->isReferenceType() && "Reference init needs a reference"); 2246 2247 // Most paths end in a failed conversion. 2248 ImplicitConversionSequence ICS; 2249 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType); 2250 2251 QualType T1 = DeclType->getAs<ReferenceType>()->getPointeeType(); 2252 QualType T2 = Init->getType(); 2253 2254 // If the initializer is the address of an overloaded function, try 2255 // to resolve the overloaded function. If all goes well, T2 is the 2256 // type of the resulting function. 2257 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) { 2258 DeclAccessPair Found; 2259 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType, 2260 false, Found)) 2261 T2 = Fn->getType(); 2262 } 2263 2264 // Compute some basic properties of the types and the initializer. 2265 bool isRValRef = DeclType->isRValueReferenceType(); 2266 bool DerivedToBase = false; 2267 Expr::isLvalueResult InitLvalue = ForceRValue ? Expr::LV_InvalidExpression : 2268 Init->isLvalue(S.Context); 2269 Sema::ReferenceCompareResult RefRelationship 2270 = S.CompareReferenceRelationship(DeclLoc, T1, T2, DerivedToBase); 2271 2272 // C++ [dcl.init.ref]p5: 2273 // A reference to type "cv1 T1" is initialized by an expression 2274 // of type "cv2 T2" as follows: 2275 2276 // -- If the initializer expression 2277 2278 // C++ [over.ics.ref]p3: 2279 // Except for an implicit object parameter, for which see 13.3.1, 2280 // a standard conversion sequence cannot be formed if it requires 2281 // binding an lvalue reference to non-const to an rvalue or 2282 // binding an rvalue reference to an lvalue. 2283 if (isRValRef && InitLvalue == Expr::LV_Valid) 2284 return ICS; 2285 2286 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is 2287 // reference-compatible with "cv2 T2," or 2288 // 2289 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here. 2290 if (InitLvalue == Expr::LV_Valid && 2291 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2292 // C++ [over.ics.ref]p1: 2293 // When a parameter of reference type binds directly (8.5.3) 2294 // to an argument expression, the implicit conversion sequence 2295 // is the identity conversion, unless the argument expression 2296 // has a type that is a derived class of the parameter type, 2297 // in which case the implicit conversion sequence is a 2298 // derived-to-base Conversion (13.3.3.1). 2299 ICS.setStandard(); 2300 ICS.Standard.First = ICK_Identity; 2301 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2302 ICS.Standard.Third = ICK_Identity; 2303 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2304 ICS.Standard.setToType(0, T2); 2305 ICS.Standard.setToType(1, T1); 2306 ICS.Standard.setToType(2, T1); 2307 ICS.Standard.ReferenceBinding = true; 2308 ICS.Standard.DirectBinding = true; 2309 ICS.Standard.RRefBinding = false; 2310 ICS.Standard.CopyConstructor = 0; 2311 2312 // Nothing more to do: the inaccessibility/ambiguity check for 2313 // derived-to-base conversions is suppressed when we're 2314 // computing the implicit conversion sequence (C++ 2315 // [over.best.ics]p2). 2316 return ICS; 2317 } 2318 2319 // -- has a class type (i.e., T2 is a class type), where T1 is 2320 // not reference-related to T2, and can be implicitly 2321 // converted to an lvalue of type "cv3 T3," where "cv1 T1" 2322 // is reference-compatible with "cv3 T3" 92) (this 2323 // conversion is selected by enumerating the applicable 2324 // conversion functions (13.3.1.6) and choosing the best 2325 // one through overload resolution (13.3)), 2326 if (!isRValRef && !SuppressUserConversions && T2->isRecordType() && 2327 !S.RequireCompleteType(DeclLoc, T2, 0) && 2328 RefRelationship == Sema::Ref_Incompatible) { 2329 CXXRecordDecl *T2RecordDecl 2330 = dyn_cast<CXXRecordDecl>(T2->getAs<RecordType>()->getDecl()); 2331 2332 OverloadCandidateSet CandidateSet(DeclLoc); 2333 const UnresolvedSetImpl *Conversions 2334 = T2RecordDecl->getVisibleConversionFunctions(); 2335 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 2336 E = Conversions->end(); I != E; ++I) { 2337 NamedDecl *D = *I; 2338 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext()); 2339 if (isa<UsingShadowDecl>(D)) 2340 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 2341 2342 FunctionTemplateDecl *ConvTemplate 2343 = dyn_cast<FunctionTemplateDecl>(D); 2344 CXXConversionDecl *Conv; 2345 if (ConvTemplate) 2346 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 2347 else 2348 Conv = cast<CXXConversionDecl>(D); 2349 2350 // If the conversion function doesn't return a reference type, 2351 // it can't be considered for this conversion. 2352 if (Conv->getConversionType()->isLValueReferenceType() && 2353 (AllowExplicit || !Conv->isExplicit())) { 2354 if (ConvTemplate) 2355 S.AddTemplateConversionCandidate(ConvTemplate, I.getPair(), ActingDC, 2356 Init, DeclType, CandidateSet); 2357 else 2358 S.AddConversionCandidate(Conv, I.getPair(), ActingDC, Init, 2359 DeclType, CandidateSet); 2360 } 2361 } 2362 2363 OverloadCandidateSet::iterator Best; 2364 switch (S.BestViableFunction(CandidateSet, DeclLoc, Best)) { 2365 case OR_Success: 2366 // C++ [over.ics.ref]p1: 2367 // 2368 // [...] If the parameter binds directly to the result of 2369 // applying a conversion function to the argument 2370 // expression, the implicit conversion sequence is a 2371 // user-defined conversion sequence (13.3.3.1.2), with the 2372 // second standard conversion sequence either an identity 2373 // conversion or, if the conversion function returns an 2374 // entity of a type that is a derived class of the parameter 2375 // type, a derived-to-base Conversion. 2376 if (!Best->FinalConversion.DirectBinding) 2377 break; 2378 2379 ICS.setUserDefined(); 2380 ICS.UserDefined.Before = Best->Conversions[0].Standard; 2381 ICS.UserDefined.After = Best->FinalConversion; 2382 ICS.UserDefined.ConversionFunction = Best->Function; 2383 ICS.UserDefined.EllipsisConversion = false; 2384 assert(ICS.UserDefined.After.ReferenceBinding && 2385 ICS.UserDefined.After.DirectBinding && 2386 "Expected a direct reference binding!"); 2387 return ICS; 2388 2389 case OR_Ambiguous: 2390 ICS.setAmbiguous(); 2391 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 2392 Cand != CandidateSet.end(); ++Cand) 2393 if (Cand->Viable) 2394 ICS.Ambiguous.addConversion(Cand->Function); 2395 return ICS; 2396 2397 case OR_No_Viable_Function: 2398 case OR_Deleted: 2399 // There was no suitable conversion, or we found a deleted 2400 // conversion; continue with other checks. 2401 break; 2402 } 2403 } 2404 2405 // -- Otherwise, the reference shall be to a non-volatile const 2406 // type (i.e., cv1 shall be const), or the reference shall be an 2407 // rvalue reference and the initializer expression shall be an rvalue. 2408 if (!isRValRef && T1.getCVRQualifiers() != Qualifiers::Const) 2409 return ICS; 2410 2411 // -- If the initializer expression is an rvalue, with T2 a 2412 // class type, and "cv1 T1" is reference-compatible with 2413 // "cv2 T2," the reference is bound in one of the 2414 // following ways (the choice is implementation-defined): 2415 // 2416 // -- The reference is bound to the object represented by 2417 // the rvalue (see 3.10) or to a sub-object within that 2418 // object. 2419 // 2420 // -- A temporary of type "cv1 T2" [sic] is created, and 2421 // a constructor is called to copy the entire rvalue 2422 // object into the temporary. The reference is bound to 2423 // the temporary or to a sub-object within the 2424 // temporary. 2425 // 2426 // The constructor that would be used to make the copy 2427 // shall be callable whether or not the copy is actually 2428 // done. 2429 // 2430 // Note that C++0x [dcl.init.ref]p5 takes away this implementation 2431 // freedom, so we will always take the first option and never build 2432 // a temporary in this case. 2433 if (InitLvalue != Expr::LV_Valid && T2->isRecordType() && 2434 RefRelationship >= Sema::Ref_Compatible_With_Added_Qualification) { 2435 ICS.setStandard(); 2436 ICS.Standard.First = ICK_Identity; 2437 ICS.Standard.Second = DerivedToBase? ICK_Derived_To_Base : ICK_Identity; 2438 ICS.Standard.Third = ICK_Identity; 2439 ICS.Standard.FromTypePtr = T2.getAsOpaquePtr(); 2440 ICS.Standard.setToType(0, T2); 2441 ICS.Standard.setToType(1, T1); 2442 ICS.Standard.setToType(2, T1); 2443 ICS.Standard.ReferenceBinding = true; 2444 ICS.Standard.DirectBinding = false; 2445 ICS.Standard.RRefBinding = isRValRef; 2446 ICS.Standard.CopyConstructor = 0; 2447 return ICS; 2448 } 2449 2450 // -- Otherwise, a temporary of type "cv1 T1" is created and 2451 // initialized from the initializer expression using the 2452 // rules for a non-reference copy initialization (8.5). The 2453 // reference is then bound to the temporary. If T1 is 2454 // reference-related to T2, cv1 must be the same 2455 // cv-qualification as, or greater cv-qualification than, 2456 // cv2; otherwise, the program is ill-formed. 2457 if (RefRelationship == Sema::Ref_Related) { 2458 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then 2459 // we would be reference-compatible or reference-compatible with 2460 // added qualification. But that wasn't the case, so the reference 2461 // initialization fails. 2462 return ICS; 2463 } 2464 2465 // If at least one of the types is a class type, the types are not 2466 // related, and we aren't allowed any user conversions, the 2467 // reference binding fails. This case is important for breaking 2468 // recursion, since TryImplicitConversion below will attempt to 2469 // create a temporary through the use of a copy constructor. 2470 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible && 2471 (T1->isRecordType() || T2->isRecordType())) 2472 return ICS; 2473 2474 // C++ [over.ics.ref]p2: 2475 // 2476 // When a parameter of reference type is not bound directly to 2477 // an argument expression, the conversion sequence is the one 2478 // required to convert the argument expression to the 2479 // underlying type of the reference according to 2480 // 13.3.3.1. Conceptually, this conversion sequence corresponds 2481 // to copy-initializing a temporary of the underlying type with 2482 // the argument expression. Any difference in top-level 2483 // cv-qualification is subsumed by the initialization itself 2484 // and does not constitute a conversion. 2485 ICS = S.TryImplicitConversion(Init, T1, SuppressUserConversions, 2486 /*AllowExplicit=*/false, 2487 /*ForceRValue=*/false, 2488 /*InOverloadResolution=*/false); 2489 2490 // Of course, that's still a reference binding. 2491 if (ICS.isStandard()) { 2492 ICS.Standard.ReferenceBinding = true; 2493 ICS.Standard.RRefBinding = isRValRef; 2494 } else if (ICS.isUserDefined()) { 2495 ICS.UserDefined.After.ReferenceBinding = true; 2496 ICS.UserDefined.After.RRefBinding = isRValRef; 2497 } 2498 return ICS; 2499} 2500 2501/// TryCopyInitialization - Try to copy-initialize a value of type 2502/// ToType from the expression From. Return the implicit conversion 2503/// sequence required to pass this argument, which may be a bad 2504/// conversion sequence (meaning that the argument cannot be passed to 2505/// a parameter of this type). If @p SuppressUserConversions, then we 2506/// do not permit any user-defined conversion sequences. If @p ForceRValue, 2507/// then we treat @p From as an rvalue, even if it is an lvalue. 2508ImplicitConversionSequence 2509Sema::TryCopyInitialization(Expr *From, QualType ToType, 2510 bool SuppressUserConversions, bool ForceRValue, 2511 bool InOverloadResolution) { 2512 if (ToType->isReferenceType()) 2513 return TryReferenceInit(*this, From, ToType, 2514 /*FIXME:*/From->getLocStart(), 2515 SuppressUserConversions, 2516 /*AllowExplicit=*/false, 2517 ForceRValue); 2518 2519 return TryImplicitConversion(From, ToType, 2520 SuppressUserConversions, 2521 /*AllowExplicit=*/false, 2522 ForceRValue, 2523 InOverloadResolution); 2524} 2525 2526/// TryObjectArgumentInitialization - Try to initialize the object 2527/// parameter of the given member function (@c Method) from the 2528/// expression @p From. 2529ImplicitConversionSequence 2530Sema::TryObjectArgumentInitialization(QualType OrigFromType, 2531 CXXMethodDecl *Method, 2532 CXXRecordDecl *ActingContext) { 2533 QualType ClassType = Context.getTypeDeclType(ActingContext); 2534 // [class.dtor]p2: A destructor can be invoked for a const, volatile or 2535 // const volatile object. 2536 unsigned Quals = isa<CXXDestructorDecl>(Method) ? 2537 Qualifiers::Const | Qualifiers::Volatile : Method->getTypeQualifiers(); 2538 QualType ImplicitParamType = Context.getCVRQualifiedType(ClassType, Quals); 2539 2540 // Set up the conversion sequence as a "bad" conversion, to allow us 2541 // to exit early. 2542 ImplicitConversionSequence ICS; 2543 2544 // We need to have an object of class type. 2545 QualType FromType = OrigFromType; 2546 if (const PointerType *PT = FromType->getAs<PointerType>()) 2547 FromType = PT->getPointeeType(); 2548 2549 assert(FromType->isRecordType()); 2550 2551 // The implicit object parameter is has the type "reference to cv X", 2552 // where X is the class of which the function is a member 2553 // (C++ [over.match.funcs]p4). However, when finding an implicit 2554 // conversion sequence for the argument, we are not allowed to 2555 // create temporaries or perform user-defined conversions 2556 // (C++ [over.match.funcs]p5). We perform a simplified version of 2557 // reference binding here, that allows class rvalues to bind to 2558 // non-constant references. 2559 2560 // First check the qualifiers. We don't care about lvalue-vs-rvalue 2561 // with the implicit object parameter (C++ [over.match.funcs]p5). 2562 QualType FromTypeCanon = Context.getCanonicalType(FromType); 2563 if (ImplicitParamType.getCVRQualifiers() 2564 != FromTypeCanon.getLocalCVRQualifiers() && 2565 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) { 2566 ICS.setBad(BadConversionSequence::bad_qualifiers, 2567 OrigFromType, ImplicitParamType); 2568 return ICS; 2569 } 2570 2571 // Check that we have either the same type or a derived type. It 2572 // affects the conversion rank. 2573 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 2574 ImplicitConversionKind SecondKind; 2575 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) { 2576 SecondKind = ICK_Identity; 2577 } else if (IsDerivedFrom(FromType, ClassType)) 2578 SecondKind = ICK_Derived_To_Base; 2579 else { 2580 ICS.setBad(BadConversionSequence::unrelated_class, 2581 FromType, ImplicitParamType); 2582 return ICS; 2583 } 2584 2585 // Success. Mark this as a reference binding. 2586 ICS.setStandard(); 2587 ICS.Standard.setAsIdentityConversion(); 2588 ICS.Standard.Second = SecondKind; 2589 ICS.Standard.setFromType(FromType); 2590 ICS.Standard.setAllToTypes(ImplicitParamType); 2591 ICS.Standard.ReferenceBinding = true; 2592 ICS.Standard.DirectBinding = true; 2593 ICS.Standard.RRefBinding = false; 2594 return ICS; 2595} 2596 2597/// PerformObjectArgumentInitialization - Perform initialization of 2598/// the implicit object parameter for the given Method with the given 2599/// expression. 2600bool 2601Sema::PerformObjectArgumentInitialization(Expr *&From, 2602 NestedNameSpecifier *Qualifier, 2603 NamedDecl *FoundDecl, 2604 CXXMethodDecl *Method) { 2605 QualType FromRecordType, DestType; 2606 QualType ImplicitParamRecordType = 2607 Method->getThisType(Context)->getAs<PointerType>()->getPointeeType(); 2608 2609 if (const PointerType *PT = From->getType()->getAs<PointerType>()) { 2610 FromRecordType = PT->getPointeeType(); 2611 DestType = Method->getThisType(Context); 2612 } else { 2613 FromRecordType = From->getType(); 2614 DestType = ImplicitParamRecordType; 2615 } 2616 2617 // Note that we always use the true parent context when performing 2618 // the actual argument initialization. 2619 ImplicitConversionSequence ICS 2620 = TryObjectArgumentInitialization(From->getType(), Method, 2621 Method->getParent()); 2622 if (ICS.isBad()) 2623 return Diag(From->getSourceRange().getBegin(), 2624 diag::err_implicit_object_parameter_init) 2625 << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); 2626 2627 if (ICS.Standard.Second == ICK_Derived_To_Base) 2628 return PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method); 2629 2630 if (!Context.hasSameType(From->getType(), DestType)) 2631 ImpCastExprToType(From, DestType, CastExpr::CK_NoOp, 2632 /*isLvalue=*/!From->getType()->getAs<PointerType>()); 2633 return false; 2634} 2635 2636/// TryContextuallyConvertToBool - Attempt to contextually convert the 2637/// expression From to bool (C++0x [conv]p3). 2638ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 2639 return TryImplicitConversion(From, Context.BoolTy, 2640 // FIXME: Are these flags correct? 2641 /*SuppressUserConversions=*/false, 2642 /*AllowExplicit=*/true, 2643 /*ForceRValue=*/false, 2644 /*InOverloadResolution=*/false); 2645} 2646 2647/// PerformContextuallyConvertToBool - Perform a contextual conversion 2648/// of the expression From to bool (C++0x [conv]p3). 2649bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2650 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2651 if (!ICS.isBad()) 2652 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting); 2653 2654 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2655 return Diag(From->getSourceRange().getBegin(), 2656 diag::err_typecheck_bool_condition) 2657 << From->getType() << From->getSourceRange(); 2658 return true; 2659} 2660 2661/// AddOverloadCandidate - Adds the given function to the set of 2662/// candidate functions, using the given function call arguments. If 2663/// @p SuppressUserConversions, then don't allow user-defined 2664/// conversions via constructors or conversion operators. 2665/// If @p ForceRValue, treat all arguments as rvalues. This is a slightly 2666/// hacky way to implement the overloading rules for elidable copy 2667/// initialization in C++0x (C++0x 12.8p15). 2668/// 2669/// \para PartialOverloading true if we are performing "partial" overloading 2670/// based on an incomplete set of function arguments. This feature is used by 2671/// code completion. 2672void 2673Sema::AddOverloadCandidate(FunctionDecl *Function, 2674 DeclAccessPair FoundDecl, 2675 Expr **Args, unsigned NumArgs, 2676 OverloadCandidateSet& CandidateSet, 2677 bool SuppressUserConversions, 2678 bool ForceRValue, 2679 bool PartialOverloading) { 2680 const FunctionProtoType* Proto 2681 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2682 assert(Proto && "Functions without a prototype cannot be overloaded"); 2683 assert(!Function->getDescribedFunctionTemplate() && 2684 "Use AddTemplateOverloadCandidate for function templates"); 2685 2686 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2687 if (!isa<CXXConstructorDecl>(Method)) { 2688 // If we get here, it's because we're calling a member function 2689 // that is named without a member access expression (e.g., 2690 // "this->f") that was either written explicitly or created 2691 // implicitly. This can happen with a qualified call to a member 2692 // function, e.g., X::f(). We use an empty type for the implied 2693 // object argument (C++ [over.call.func]p3), and the acting context 2694 // is irrelevant. 2695 AddMethodCandidate(Method, FoundDecl, Method->getParent(), 2696 QualType(), Args, NumArgs, CandidateSet, 2697 SuppressUserConversions, ForceRValue); 2698 return; 2699 } 2700 // We treat a constructor like a non-member function, since its object 2701 // argument doesn't participate in overload resolution. 2702 } 2703 2704 if (!CandidateSet.isNewCandidate(Function)) 2705 return; 2706 2707 // Overload resolution is always an unevaluated context. 2708 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2709 2710 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2711 // C++ [class.copy]p3: 2712 // A member function template is never instantiated to perform the copy 2713 // of a class object to an object of its class type. 2714 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2715 if (NumArgs == 1 && 2716 Constructor->isCopyConstructorLikeSpecialization() && 2717 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) || 2718 IsDerivedFrom(Args[0]->getType(), ClassType))) 2719 return; 2720 } 2721 2722 // Add this candidate 2723 CandidateSet.push_back(OverloadCandidate()); 2724 OverloadCandidate& Candidate = CandidateSet.back(); 2725 Candidate.FoundDecl = FoundDecl; 2726 Candidate.Function = Function; 2727 Candidate.Viable = true; 2728 Candidate.IsSurrogate = false; 2729 Candidate.IgnoreObjectArgument = false; 2730 2731 unsigned NumArgsInProto = Proto->getNumArgs(); 2732 2733 // (C++ 13.3.2p2): A candidate function having fewer than m 2734 // parameters is viable only if it has an ellipsis in its parameter 2735 // list (8.3.5). 2736 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 2737 !Proto->isVariadic()) { 2738 Candidate.Viable = false; 2739 Candidate.FailureKind = ovl_fail_too_many_arguments; 2740 return; 2741 } 2742 2743 // (C++ 13.3.2p2): A candidate function having more than m parameters 2744 // is viable only if the (m+1)st parameter has a default argument 2745 // (8.3.6). For the purposes of overload resolution, the 2746 // parameter list is truncated on the right, so that there are 2747 // exactly m parameters. 2748 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2749 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 2750 // Not enough arguments. 2751 Candidate.Viable = false; 2752 Candidate.FailureKind = ovl_fail_too_few_arguments; 2753 return; 2754 } 2755 2756 // Determine the implicit conversion sequences for each of the 2757 // arguments. 2758 Candidate.Conversions.resize(NumArgs); 2759 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2760 if (ArgIdx < NumArgsInProto) { 2761 // (C++ 13.3.2p3): for F to be a viable function, there shall 2762 // exist for each argument an implicit conversion sequence 2763 // (13.3.3.1) that converts that argument to the corresponding 2764 // parameter of F. 2765 QualType ParamType = Proto->getArgType(ArgIdx); 2766 Candidate.Conversions[ArgIdx] 2767 = TryCopyInitialization(Args[ArgIdx], ParamType, 2768 SuppressUserConversions, ForceRValue, 2769 /*InOverloadResolution=*/true); 2770 if (Candidate.Conversions[ArgIdx].isBad()) { 2771 Candidate.Viable = false; 2772 Candidate.FailureKind = ovl_fail_bad_conversion; 2773 break; 2774 } 2775 } else { 2776 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2777 // argument for which there is no corresponding parameter is 2778 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2779 Candidate.Conversions[ArgIdx].setEllipsis(); 2780 } 2781 } 2782} 2783 2784/// \brief Add all of the function declarations in the given function set to 2785/// the overload canddiate set. 2786void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns, 2787 Expr **Args, unsigned NumArgs, 2788 OverloadCandidateSet& CandidateSet, 2789 bool SuppressUserConversions) { 2790 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) { 2791 NamedDecl *D = F.getDecl()->getUnderlyingDecl(); 2792 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 2793 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 2794 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(), 2795 cast<CXXMethodDecl>(FD)->getParent(), 2796 Args[0]->getType(), Args + 1, NumArgs - 1, 2797 CandidateSet, SuppressUserConversions); 2798 else 2799 AddOverloadCandidate(FD, F.getPair(), Args, NumArgs, CandidateSet, 2800 SuppressUserConversions); 2801 } else { 2802 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(D); 2803 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 2804 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 2805 AddMethodTemplateCandidate(FunTmpl, F.getPair(), 2806 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 2807 /*FIXME: explicit args */ 0, 2808 Args[0]->getType(), Args + 1, NumArgs - 1, 2809 CandidateSet, 2810 SuppressUserConversions); 2811 else 2812 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), 2813 /*FIXME: explicit args */ 0, 2814 Args, NumArgs, CandidateSet, 2815 SuppressUserConversions); 2816 } 2817 } 2818} 2819 2820/// AddMethodCandidate - Adds a named decl (which is some kind of 2821/// method) as a method candidate to the given overload set. 2822void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, 2823 QualType ObjectType, 2824 Expr **Args, unsigned NumArgs, 2825 OverloadCandidateSet& CandidateSet, 2826 bool SuppressUserConversions, bool ForceRValue) { 2827 NamedDecl *Decl = FoundDecl.getDecl(); 2828 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 2829 2830 if (isa<UsingShadowDecl>(Decl)) 2831 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 2832 2833 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 2834 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 2835 "Expected a member function template"); 2836 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext, 2837 /*ExplicitArgs*/ 0, 2838 ObjectType, Args, NumArgs, 2839 CandidateSet, 2840 SuppressUserConversions, 2841 ForceRValue); 2842 } else { 2843 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext, 2844 ObjectType, Args, NumArgs, 2845 CandidateSet, SuppressUserConversions, ForceRValue); 2846 } 2847} 2848 2849/// AddMethodCandidate - Adds the given C++ member function to the set 2850/// of candidate functions, using the given function call arguments 2851/// and the object argument (@c Object). For example, in a call 2852/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2853/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2854/// allow user-defined conversions via constructors or conversion 2855/// operators. If @p ForceRValue, treat all arguments as rvalues. This is 2856/// a slightly hacky way to implement the overloading rules for elidable copy 2857/// initialization in C++0x (C++0x 12.8p15). 2858void 2859Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl, 2860 CXXRecordDecl *ActingContext, QualType ObjectType, 2861 Expr **Args, unsigned NumArgs, 2862 OverloadCandidateSet& CandidateSet, 2863 bool SuppressUserConversions, bool ForceRValue) { 2864 const FunctionProtoType* Proto 2865 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 2866 assert(Proto && "Methods without a prototype cannot be overloaded"); 2867 assert(!isa<CXXConstructorDecl>(Method) && 2868 "Use AddOverloadCandidate for constructors"); 2869 2870 if (!CandidateSet.isNewCandidate(Method)) 2871 return; 2872 2873 // Overload resolution is always an unevaluated context. 2874 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2875 2876 // Add this candidate 2877 CandidateSet.push_back(OverloadCandidate()); 2878 OverloadCandidate& Candidate = CandidateSet.back(); 2879 Candidate.FoundDecl = FoundDecl; 2880 Candidate.Function = Method; 2881 Candidate.IsSurrogate = false; 2882 Candidate.IgnoreObjectArgument = false; 2883 2884 unsigned NumArgsInProto = Proto->getNumArgs(); 2885 2886 // (C++ 13.3.2p2): A candidate function having fewer than m 2887 // parameters is viable only if it has an ellipsis in its parameter 2888 // list (8.3.5). 2889 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2890 Candidate.Viable = false; 2891 Candidate.FailureKind = ovl_fail_too_many_arguments; 2892 return; 2893 } 2894 2895 // (C++ 13.3.2p2): A candidate function having more than m parameters 2896 // is viable only if the (m+1)st parameter has a default argument 2897 // (8.3.6). For the purposes of overload resolution, the 2898 // parameter list is truncated on the right, so that there are 2899 // exactly m parameters. 2900 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2901 if (NumArgs < MinRequiredArgs) { 2902 // Not enough arguments. 2903 Candidate.Viable = false; 2904 Candidate.FailureKind = ovl_fail_too_few_arguments; 2905 return; 2906 } 2907 2908 Candidate.Viable = true; 2909 Candidate.Conversions.resize(NumArgs + 1); 2910 2911 if (Method->isStatic() || ObjectType.isNull()) 2912 // The implicit object argument is ignored. 2913 Candidate.IgnoreObjectArgument = true; 2914 else { 2915 // Determine the implicit conversion sequence for the object 2916 // parameter. 2917 Candidate.Conversions[0] 2918 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 2919 if (Candidate.Conversions[0].isBad()) { 2920 Candidate.Viable = false; 2921 Candidate.FailureKind = ovl_fail_bad_conversion; 2922 return; 2923 } 2924 } 2925 2926 // Determine the implicit conversion sequences for each of the 2927 // arguments. 2928 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2929 if (ArgIdx < NumArgsInProto) { 2930 // (C++ 13.3.2p3): for F to be a viable function, there shall 2931 // exist for each argument an implicit conversion sequence 2932 // (13.3.3.1) that converts that argument to the corresponding 2933 // parameter of F. 2934 QualType ParamType = Proto->getArgType(ArgIdx); 2935 Candidate.Conversions[ArgIdx + 1] 2936 = TryCopyInitialization(Args[ArgIdx], ParamType, 2937 SuppressUserConversions, ForceRValue, 2938 /*InOverloadResolution=*/true); 2939 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 2940 Candidate.Viable = false; 2941 Candidate.FailureKind = ovl_fail_bad_conversion; 2942 break; 2943 } 2944 } else { 2945 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2946 // argument for which there is no corresponding parameter is 2947 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2948 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 2949 } 2950 } 2951} 2952 2953/// \brief Add a C++ member function template as a candidate to the candidate 2954/// set, using template argument deduction to produce an appropriate member 2955/// function template specialization. 2956void 2957Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 2958 DeclAccessPair FoundDecl, 2959 CXXRecordDecl *ActingContext, 2960 const TemplateArgumentListInfo *ExplicitTemplateArgs, 2961 QualType ObjectType, 2962 Expr **Args, unsigned NumArgs, 2963 OverloadCandidateSet& CandidateSet, 2964 bool SuppressUserConversions, 2965 bool ForceRValue) { 2966 if (!CandidateSet.isNewCandidate(MethodTmpl)) 2967 return; 2968 2969 // C++ [over.match.funcs]p7: 2970 // In each case where a candidate is a function template, candidate 2971 // function template specializations are generated using template argument 2972 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 2973 // candidate functions in the usual way.113) A given name can refer to one 2974 // or more function templates and also to a set of overloaded non-template 2975 // functions. In such a case, the candidate functions generated from each 2976 // function template are combined with the set of non-template candidate 2977 // functions. 2978 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 2979 FunctionDecl *Specialization = 0; 2980 if (TemplateDeductionResult Result 2981 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 2982 Args, NumArgs, Specialization, Info)) { 2983 // FIXME: Record what happened with template argument deduction, so 2984 // that we can give the user a beautiful diagnostic. 2985 (void)Result; 2986 return; 2987 } 2988 2989 // Add the function template specialization produced by template argument 2990 // deduction as a candidate. 2991 assert(Specialization && "Missing member function template specialization?"); 2992 assert(isa<CXXMethodDecl>(Specialization) && 2993 "Specialization is not a member function?"); 2994 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl, 2995 ActingContext, ObjectType, Args, NumArgs, 2996 CandidateSet, SuppressUserConversions, ForceRValue); 2997} 2998 2999/// \brief Add a C++ function template specialization as a candidate 3000/// in the candidate set, using template argument deduction to produce 3001/// an appropriate function template specialization. 3002void 3003Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 3004 DeclAccessPair FoundDecl, 3005 const TemplateArgumentListInfo *ExplicitTemplateArgs, 3006 Expr **Args, unsigned NumArgs, 3007 OverloadCandidateSet& CandidateSet, 3008 bool SuppressUserConversions, 3009 bool ForceRValue) { 3010 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3011 return; 3012 3013 // C++ [over.match.funcs]p7: 3014 // In each case where a candidate is a function template, candidate 3015 // function template specializations are generated using template argument 3016 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 3017 // candidate functions in the usual way.113) A given name can refer to one 3018 // or more function templates and also to a set of overloaded non-template 3019 // functions. In such a case, the candidate functions generated from each 3020 // function template are combined with the set of non-template candidate 3021 // functions. 3022 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3023 FunctionDecl *Specialization = 0; 3024 if (TemplateDeductionResult Result 3025 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 3026 Args, NumArgs, Specialization, Info)) { 3027 CandidateSet.push_back(OverloadCandidate()); 3028 OverloadCandidate &Candidate = CandidateSet.back(); 3029 Candidate.FoundDecl = FoundDecl; 3030 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 3031 Candidate.Viable = false; 3032 Candidate.FailureKind = ovl_fail_bad_deduction; 3033 Candidate.IsSurrogate = false; 3034 Candidate.IgnoreObjectArgument = false; 3035 3036 // TODO: record more information about failed template arguments 3037 Candidate.DeductionFailure.Result = Result; 3038 Candidate.DeductionFailure.TemplateParameter = Info.Param.getOpaqueValue(); 3039 return; 3040 } 3041 3042 // Add the function template specialization produced by template argument 3043 // deduction as a candidate. 3044 assert(Specialization && "Missing function template specialization?"); 3045 AddOverloadCandidate(Specialization, FoundDecl, Args, NumArgs, CandidateSet, 3046 SuppressUserConversions, ForceRValue); 3047} 3048 3049/// AddConversionCandidate - Add a C++ conversion function as a 3050/// candidate in the candidate set (C++ [over.match.conv], 3051/// C++ [over.match.copy]). From is the expression we're converting from, 3052/// and ToType is the type that we're eventually trying to convert to 3053/// (which may or may not be the same type as the type that the 3054/// conversion function produces). 3055void 3056Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 3057 DeclAccessPair FoundDecl, 3058 CXXRecordDecl *ActingContext, 3059 Expr *From, QualType ToType, 3060 OverloadCandidateSet& CandidateSet) { 3061 assert(!Conversion->getDescribedFunctionTemplate() && 3062 "Conversion function templates use AddTemplateConversionCandidate"); 3063 3064 if (!CandidateSet.isNewCandidate(Conversion)) 3065 return; 3066 3067 // Overload resolution is always an unevaluated context. 3068 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3069 3070 // Add this candidate 3071 CandidateSet.push_back(OverloadCandidate()); 3072 OverloadCandidate& Candidate = CandidateSet.back(); 3073 Candidate.FoundDecl = FoundDecl; 3074 Candidate.Function = Conversion; 3075 Candidate.IsSurrogate = false; 3076 Candidate.IgnoreObjectArgument = false; 3077 Candidate.FinalConversion.setAsIdentityConversion(); 3078 Candidate.FinalConversion.setFromType(Conversion->getConversionType()); 3079 Candidate.FinalConversion.setAllToTypes(ToType); 3080 3081 // Determine the implicit conversion sequence for the implicit 3082 // object parameter. 3083 Candidate.Viable = true; 3084 Candidate.Conversions.resize(1); 3085 Candidate.Conversions[0] 3086 = TryObjectArgumentInitialization(From->getType(), Conversion, 3087 ActingContext); 3088 // Conversion functions to a different type in the base class is visible in 3089 // the derived class. So, a derived to base conversion should not participate 3090 // in overload resolution. 3091 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 3092 Candidate.Conversions[0].Standard.Second = ICK_Identity; 3093 if (Candidate.Conversions[0].isBad()) { 3094 Candidate.Viable = false; 3095 Candidate.FailureKind = ovl_fail_bad_conversion; 3096 return; 3097 } 3098 3099 // We won't go through a user-define type conversion function to convert a 3100 // derived to base as such conversions are given Conversion Rank. They only 3101 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 3102 QualType FromCanon 3103 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 3104 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 3105 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 3106 Candidate.Viable = false; 3107 Candidate.FailureKind = ovl_fail_trivial_conversion; 3108 return; 3109 } 3110 3111 3112 // To determine what the conversion from the result of calling the 3113 // conversion function to the type we're eventually trying to 3114 // convert to (ToType), we need to synthesize a call to the 3115 // conversion function and attempt copy initialization from it. This 3116 // makes sure that we get the right semantics with respect to 3117 // lvalues/rvalues and the type. Fortunately, we can allocate this 3118 // call on the stack and we don't need its arguments to be 3119 // well-formed. 3120 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 3121 From->getLocStart()); 3122 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 3123 CastExpr::CK_FunctionToPointerDecay, 3124 &ConversionRef, false); 3125 3126 // Note that it is safe to allocate CallExpr on the stack here because 3127 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 3128 // allocator). 3129 CallExpr Call(Context, &ConversionFn, 0, 0, 3130 Conversion->getConversionType().getNonReferenceType(), 3131 From->getLocStart()); 3132 ImplicitConversionSequence ICS = 3133 TryCopyInitialization(&Call, ToType, 3134 /*SuppressUserConversions=*/true, 3135 /*ForceRValue=*/false, 3136 /*InOverloadResolution=*/false); 3137 3138 switch (ICS.getKind()) { 3139 case ImplicitConversionSequence::StandardConversion: 3140 Candidate.FinalConversion = ICS.Standard; 3141 3142 // C++ [over.ics.user]p3: 3143 // If the user-defined conversion is specified by a specialization of a 3144 // conversion function template, the second standard conversion sequence 3145 // shall have exact match rank. 3146 if (Conversion->getPrimaryTemplate() && 3147 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) { 3148 Candidate.Viable = false; 3149 Candidate.FailureKind = ovl_fail_final_conversion_not_exact; 3150 } 3151 3152 break; 3153 3154 case ImplicitConversionSequence::BadConversion: 3155 Candidate.Viable = false; 3156 Candidate.FailureKind = ovl_fail_bad_final_conversion; 3157 break; 3158 3159 default: 3160 assert(false && 3161 "Can only end up with a standard conversion sequence or failure"); 3162 } 3163} 3164 3165/// \brief Adds a conversion function template specialization 3166/// candidate to the overload set, using template argument deduction 3167/// to deduce the template arguments of the conversion function 3168/// template from the type that we are converting to (C++ 3169/// [temp.deduct.conv]). 3170void 3171Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 3172 DeclAccessPair FoundDecl, 3173 CXXRecordDecl *ActingDC, 3174 Expr *From, QualType ToType, 3175 OverloadCandidateSet &CandidateSet) { 3176 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 3177 "Only conversion function templates permitted here"); 3178 3179 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 3180 return; 3181 3182 TemplateDeductionInfo Info(Context, CandidateSet.getLocation()); 3183 CXXConversionDecl *Specialization = 0; 3184 if (TemplateDeductionResult Result 3185 = DeduceTemplateArguments(FunctionTemplate, ToType, 3186 Specialization, Info)) { 3187 // FIXME: Record what happened with template argument deduction, so 3188 // that we can give the user a beautiful diagnostic. 3189 (void)Result; 3190 return; 3191 } 3192 3193 // Add the conversion function template specialization produced by 3194 // template argument deduction as a candidate. 3195 assert(Specialization && "Missing function template specialization?"); 3196 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType, 3197 CandidateSet); 3198} 3199 3200/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 3201/// converts the given @c Object to a function pointer via the 3202/// conversion function @c Conversion, and then attempts to call it 3203/// with the given arguments (C++ [over.call.object]p2-4). Proto is 3204/// the type of function that we'll eventually be calling. 3205void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 3206 DeclAccessPair FoundDecl, 3207 CXXRecordDecl *ActingContext, 3208 const FunctionProtoType *Proto, 3209 QualType ObjectType, 3210 Expr **Args, unsigned NumArgs, 3211 OverloadCandidateSet& CandidateSet) { 3212 if (!CandidateSet.isNewCandidate(Conversion)) 3213 return; 3214 3215 // Overload resolution is always an unevaluated context. 3216 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3217 3218 CandidateSet.push_back(OverloadCandidate()); 3219 OverloadCandidate& Candidate = CandidateSet.back(); 3220 Candidate.FoundDecl = FoundDecl; 3221 Candidate.Function = 0; 3222 Candidate.Surrogate = Conversion; 3223 Candidate.Viable = true; 3224 Candidate.IsSurrogate = true; 3225 Candidate.IgnoreObjectArgument = false; 3226 Candidate.Conversions.resize(NumArgs + 1); 3227 3228 // Determine the implicit conversion sequence for the implicit 3229 // object parameter. 3230 ImplicitConversionSequence ObjectInit 3231 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 3232 if (ObjectInit.isBad()) { 3233 Candidate.Viable = false; 3234 Candidate.FailureKind = ovl_fail_bad_conversion; 3235 Candidate.Conversions[0] = ObjectInit; 3236 return; 3237 } 3238 3239 // The first conversion is actually a user-defined conversion whose 3240 // first conversion is ObjectInit's standard conversion (which is 3241 // effectively a reference binding). Record it as such. 3242 Candidate.Conversions[0].setUserDefined(); 3243 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 3244 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 3245 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 3246 Candidate.Conversions[0].UserDefined.After 3247 = Candidate.Conversions[0].UserDefined.Before; 3248 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 3249 3250 // Find the 3251 unsigned NumArgsInProto = Proto->getNumArgs(); 3252 3253 // (C++ 13.3.2p2): A candidate function having fewer than m 3254 // parameters is viable only if it has an ellipsis in its parameter 3255 // list (8.3.5). 3256 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 3257 Candidate.Viable = false; 3258 Candidate.FailureKind = ovl_fail_too_many_arguments; 3259 return; 3260 } 3261 3262 // Function types don't have any default arguments, so just check if 3263 // we have enough arguments. 3264 if (NumArgs < NumArgsInProto) { 3265 // Not enough arguments. 3266 Candidate.Viable = false; 3267 Candidate.FailureKind = ovl_fail_too_few_arguments; 3268 return; 3269 } 3270 3271 // Determine the implicit conversion sequences for each of the 3272 // arguments. 3273 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3274 if (ArgIdx < NumArgsInProto) { 3275 // (C++ 13.3.2p3): for F to be a viable function, there shall 3276 // exist for each argument an implicit conversion sequence 3277 // (13.3.3.1) that converts that argument to the corresponding 3278 // parameter of F. 3279 QualType ParamType = Proto->getArgType(ArgIdx); 3280 Candidate.Conversions[ArgIdx + 1] 3281 = TryCopyInitialization(Args[ArgIdx], ParamType, 3282 /*SuppressUserConversions=*/false, 3283 /*ForceRValue=*/false, 3284 /*InOverloadResolution=*/false); 3285 if (Candidate.Conversions[ArgIdx + 1].isBad()) { 3286 Candidate.Viable = false; 3287 Candidate.FailureKind = ovl_fail_bad_conversion; 3288 break; 3289 } 3290 } else { 3291 // (C++ 13.3.2p2): For the purposes of overload resolution, any 3292 // argument for which there is no corresponding parameter is 3293 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 3294 Candidate.Conversions[ArgIdx + 1].setEllipsis(); 3295 } 3296 } 3297} 3298 3299// FIXME: This will eventually be removed, once we've migrated all of the 3300// operator overloading logic over to the scheme used by binary operators, which 3301// works for template instantiation. 3302void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 3303 SourceLocation OpLoc, 3304 Expr **Args, unsigned NumArgs, 3305 OverloadCandidateSet& CandidateSet, 3306 SourceRange OpRange) { 3307 UnresolvedSet<16> Fns; 3308 3309 QualType T1 = Args[0]->getType(); 3310 QualType T2; 3311 if (NumArgs > 1) 3312 T2 = Args[1]->getType(); 3313 3314 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3315 if (S) 3316 LookupOverloadedOperatorName(Op, S, T1, T2, Fns); 3317 AddFunctionCandidates(Fns, Args, NumArgs, CandidateSet, false); 3318 AddArgumentDependentLookupCandidates(OpName, false, Args, NumArgs, 0, 3319 CandidateSet); 3320 AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange); 3321 AddBuiltinOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet); 3322} 3323 3324/// \brief Add overload candidates for overloaded operators that are 3325/// member functions. 3326/// 3327/// Add the overloaded operator candidates that are member functions 3328/// for the operator Op that was used in an operator expression such 3329/// as "x Op y". , Args/NumArgs provides the operator arguments, and 3330/// CandidateSet will store the added overload candidates. (C++ 3331/// [over.match.oper]). 3332void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 3333 SourceLocation OpLoc, 3334 Expr **Args, unsigned NumArgs, 3335 OverloadCandidateSet& CandidateSet, 3336 SourceRange OpRange) { 3337 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3338 3339 // C++ [over.match.oper]p3: 3340 // For a unary operator @ with an operand of a type whose 3341 // cv-unqualified version is T1, and for a binary operator @ with 3342 // a left operand of a type whose cv-unqualified version is T1 and 3343 // a right operand of a type whose cv-unqualified version is T2, 3344 // three sets of candidate functions, designated member 3345 // candidates, non-member candidates and built-in candidates, are 3346 // constructed as follows: 3347 QualType T1 = Args[0]->getType(); 3348 QualType T2; 3349 if (NumArgs > 1) 3350 T2 = Args[1]->getType(); 3351 3352 // -- If T1 is a class type, the set of member candidates is the 3353 // result of the qualified lookup of T1::operator@ 3354 // (13.3.1.1.1); otherwise, the set of member candidates is 3355 // empty. 3356 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 3357 // Complete the type if it can be completed. Otherwise, we're done. 3358 if (RequireCompleteType(OpLoc, T1, PDiag())) 3359 return; 3360 3361 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 3362 LookupQualifiedName(Operators, T1Rec->getDecl()); 3363 Operators.suppressDiagnostics(); 3364 3365 for (LookupResult::iterator Oper = Operators.begin(), 3366 OperEnd = Operators.end(); 3367 Oper != OperEnd; 3368 ++Oper) 3369 AddMethodCandidate(Oper.getPair(), Args[0]->getType(), 3370 Args + 1, NumArgs - 1, CandidateSet, 3371 /* SuppressUserConversions = */ false); 3372 } 3373} 3374 3375/// AddBuiltinCandidate - Add a candidate for a built-in 3376/// operator. ResultTy and ParamTys are the result and parameter types 3377/// of the built-in candidate, respectively. Args and NumArgs are the 3378/// arguments being passed to the candidate. IsAssignmentOperator 3379/// should be true when this built-in candidate is an assignment 3380/// operator. NumContextualBoolArguments is the number of arguments 3381/// (at the beginning of the argument list) that will be contextually 3382/// converted to bool. 3383void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3384 Expr **Args, unsigned NumArgs, 3385 OverloadCandidateSet& CandidateSet, 3386 bool IsAssignmentOperator, 3387 unsigned NumContextualBoolArguments) { 3388 // Overload resolution is always an unevaluated context. 3389 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3390 3391 // Add this candidate 3392 CandidateSet.push_back(OverloadCandidate()); 3393 OverloadCandidate& Candidate = CandidateSet.back(); 3394 Candidate.FoundDecl = DeclAccessPair::make(0, AS_none); 3395 Candidate.Function = 0; 3396 Candidate.IsSurrogate = false; 3397 Candidate.IgnoreObjectArgument = false; 3398 Candidate.BuiltinTypes.ResultTy = ResultTy; 3399 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3400 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3401 3402 // Determine the implicit conversion sequences for each of the 3403 // arguments. 3404 Candidate.Viable = true; 3405 Candidate.Conversions.resize(NumArgs); 3406 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3407 // C++ [over.match.oper]p4: 3408 // For the built-in assignment operators, conversions of the 3409 // left operand are restricted as follows: 3410 // -- no temporaries are introduced to hold the left operand, and 3411 // -- no user-defined conversions are applied to the left 3412 // operand to achieve a type match with the left-most 3413 // parameter of a built-in candidate. 3414 // 3415 // We block these conversions by turning off user-defined 3416 // conversions, since that is the only way that initialization of 3417 // a reference to a non-class type can occur from something that 3418 // is not of the same type. 3419 if (ArgIdx < NumContextualBoolArguments) { 3420 assert(ParamTys[ArgIdx] == Context.BoolTy && 3421 "Contextual conversion to bool requires bool type"); 3422 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3423 } else { 3424 Candidate.Conversions[ArgIdx] 3425 = TryCopyInitialization(Args[ArgIdx], ParamTys[ArgIdx], 3426 ArgIdx == 0 && IsAssignmentOperator, 3427 /*ForceRValue=*/false, 3428 /*InOverloadResolution=*/false); 3429 } 3430 if (Candidate.Conversions[ArgIdx].isBad()) { 3431 Candidate.Viable = false; 3432 Candidate.FailureKind = ovl_fail_bad_conversion; 3433 break; 3434 } 3435 } 3436} 3437 3438/// BuiltinCandidateTypeSet - A set of types that will be used for the 3439/// candidate operator functions for built-in operators (C++ 3440/// [over.built]). The types are separated into pointer types and 3441/// enumeration types. 3442class BuiltinCandidateTypeSet { 3443 /// TypeSet - A set of types. 3444 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3445 3446 /// PointerTypes - The set of pointer types that will be used in the 3447 /// built-in candidates. 3448 TypeSet PointerTypes; 3449 3450 /// MemberPointerTypes - The set of member pointer types that will be 3451 /// used in the built-in candidates. 3452 TypeSet MemberPointerTypes; 3453 3454 /// EnumerationTypes - The set of enumeration types that will be 3455 /// used in the built-in candidates. 3456 TypeSet EnumerationTypes; 3457 3458 /// Sema - The semantic analysis instance where we are building the 3459 /// candidate type set. 3460 Sema &SemaRef; 3461 3462 /// Context - The AST context in which we will build the type sets. 3463 ASTContext &Context; 3464 3465 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3466 const Qualifiers &VisibleQuals); 3467 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3468 3469public: 3470 /// iterator - Iterates through the types that are part of the set. 3471 typedef TypeSet::iterator iterator; 3472 3473 BuiltinCandidateTypeSet(Sema &SemaRef) 3474 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3475 3476 void AddTypesConvertedFrom(QualType Ty, 3477 SourceLocation Loc, 3478 bool AllowUserConversions, 3479 bool AllowExplicitConversions, 3480 const Qualifiers &VisibleTypeConversionsQuals); 3481 3482 /// pointer_begin - First pointer type found; 3483 iterator pointer_begin() { return PointerTypes.begin(); } 3484 3485 /// pointer_end - Past the last pointer type found; 3486 iterator pointer_end() { return PointerTypes.end(); } 3487 3488 /// member_pointer_begin - First member pointer type found; 3489 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3490 3491 /// member_pointer_end - Past the last member pointer type found; 3492 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3493 3494 /// enumeration_begin - First enumeration type found; 3495 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3496 3497 /// enumeration_end - Past the last enumeration type found; 3498 iterator enumeration_end() { return EnumerationTypes.end(); } 3499}; 3500 3501/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3502/// the set of pointer types along with any more-qualified variants of 3503/// that type. For example, if @p Ty is "int const *", this routine 3504/// will add "int const *", "int const volatile *", "int const 3505/// restrict *", and "int const volatile restrict *" to the set of 3506/// pointer types. Returns true if the add of @p Ty itself succeeded, 3507/// false otherwise. 3508/// 3509/// FIXME: what to do about extended qualifiers? 3510bool 3511BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3512 const Qualifiers &VisibleQuals) { 3513 3514 // Insert this type. 3515 if (!PointerTypes.insert(Ty)) 3516 return false; 3517 3518 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3519 assert(PointerTy && "type was not a pointer type!"); 3520 3521 QualType PointeeTy = PointerTy->getPointeeType(); 3522 // Don't add qualified variants of arrays. For one, they're not allowed 3523 // (the qualifier would sink to the element type), and for another, the 3524 // only overload situation where it matters is subscript or pointer +- int, 3525 // and those shouldn't have qualifier variants anyway. 3526 if (PointeeTy->isArrayType()) 3527 return true; 3528 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3529 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3530 BaseCVR = Array->getElementType().getCVRQualifiers(); 3531 bool hasVolatile = VisibleQuals.hasVolatile(); 3532 bool hasRestrict = VisibleQuals.hasRestrict(); 3533 3534 // Iterate through all strict supersets of BaseCVR. 3535 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3536 if ((CVR | BaseCVR) != CVR) continue; 3537 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3538 // in the types. 3539 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3540 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3541 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3542 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3543 } 3544 3545 return true; 3546} 3547 3548/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3549/// to the set of pointer types along with any more-qualified variants of 3550/// that type. For example, if @p Ty is "int const *", this routine 3551/// will add "int const *", "int const volatile *", "int const 3552/// restrict *", and "int const volatile restrict *" to the set of 3553/// pointer types. Returns true if the add of @p Ty itself succeeded, 3554/// false otherwise. 3555/// 3556/// FIXME: what to do about extended qualifiers? 3557bool 3558BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3559 QualType Ty) { 3560 // Insert this type. 3561 if (!MemberPointerTypes.insert(Ty)) 3562 return false; 3563 3564 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3565 assert(PointerTy && "type was not a member pointer type!"); 3566 3567 QualType PointeeTy = PointerTy->getPointeeType(); 3568 // Don't add qualified variants of arrays. For one, they're not allowed 3569 // (the qualifier would sink to the element type), and for another, the 3570 // only overload situation where it matters is subscript or pointer +- int, 3571 // and those shouldn't have qualifier variants anyway. 3572 if (PointeeTy->isArrayType()) 3573 return true; 3574 const Type *ClassTy = PointerTy->getClass(); 3575 3576 // Iterate through all strict supersets of the pointee type's CVR 3577 // qualifiers. 3578 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3579 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3580 if ((CVR | BaseCVR) != CVR) continue; 3581 3582 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3583 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3584 } 3585 3586 return true; 3587} 3588 3589/// AddTypesConvertedFrom - Add each of the types to which the type @p 3590/// Ty can be implicit converted to the given set of @p Types. We're 3591/// primarily interested in pointer types and enumeration types. We also 3592/// take member pointer types, for the conditional operator. 3593/// AllowUserConversions is true if we should look at the conversion 3594/// functions of a class type, and AllowExplicitConversions if we 3595/// should also include the explicit conversion functions of a class 3596/// type. 3597void 3598BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3599 SourceLocation Loc, 3600 bool AllowUserConversions, 3601 bool AllowExplicitConversions, 3602 const Qualifiers &VisibleQuals) { 3603 // Only deal with canonical types. 3604 Ty = Context.getCanonicalType(Ty); 3605 3606 // Look through reference types; they aren't part of the type of an 3607 // expression for the purposes of conversions. 3608 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3609 Ty = RefTy->getPointeeType(); 3610 3611 // We don't care about qualifiers on the type. 3612 Ty = Ty.getLocalUnqualifiedType(); 3613 3614 // If we're dealing with an array type, decay to the pointer. 3615 if (Ty->isArrayType()) 3616 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3617 3618 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3619 QualType PointeeTy = PointerTy->getPointeeType(); 3620 3621 // Insert our type, and its more-qualified variants, into the set 3622 // of types. 3623 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3624 return; 3625 } else if (Ty->isMemberPointerType()) { 3626 // Member pointers are far easier, since the pointee can't be converted. 3627 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3628 return; 3629 } else if (Ty->isEnumeralType()) { 3630 EnumerationTypes.insert(Ty); 3631 } else if (AllowUserConversions) { 3632 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3633 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3634 // No conversion functions in incomplete types. 3635 return; 3636 } 3637 3638 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3639 const UnresolvedSetImpl *Conversions 3640 = ClassDecl->getVisibleConversionFunctions(); 3641 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3642 E = Conversions->end(); I != E; ++I) { 3643 NamedDecl *D = I.getDecl(); 3644 if (isa<UsingShadowDecl>(D)) 3645 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3646 3647 // Skip conversion function templates; they don't tell us anything 3648 // about which builtin types we can convert to. 3649 if (isa<FunctionTemplateDecl>(D)) 3650 continue; 3651 3652 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 3653 if (AllowExplicitConversions || !Conv->isExplicit()) { 3654 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3655 VisibleQuals); 3656 } 3657 } 3658 } 3659 } 3660} 3661 3662/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3663/// the volatile- and non-volatile-qualified assignment operators for the 3664/// given type to the candidate set. 3665static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3666 QualType T, 3667 Expr **Args, 3668 unsigned NumArgs, 3669 OverloadCandidateSet &CandidateSet) { 3670 QualType ParamTypes[2]; 3671 3672 // T& operator=(T&, T) 3673 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3674 ParamTypes[1] = T; 3675 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3676 /*IsAssignmentOperator=*/true); 3677 3678 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3679 // volatile T& operator=(volatile T&, T) 3680 ParamTypes[0] 3681 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3682 ParamTypes[1] = T; 3683 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3684 /*IsAssignmentOperator=*/true); 3685 } 3686} 3687 3688/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3689/// if any, found in visible type conversion functions found in ArgExpr's type. 3690static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3691 Qualifiers VRQuals; 3692 const RecordType *TyRec; 3693 if (const MemberPointerType *RHSMPType = 3694 ArgExpr->getType()->getAs<MemberPointerType>()) 3695 TyRec = cast<RecordType>(RHSMPType->getClass()); 3696 else 3697 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3698 if (!TyRec) { 3699 // Just to be safe, assume the worst case. 3700 VRQuals.addVolatile(); 3701 VRQuals.addRestrict(); 3702 return VRQuals; 3703 } 3704 3705 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3706 if (!ClassDecl->hasDefinition()) 3707 return VRQuals; 3708 3709 const UnresolvedSetImpl *Conversions = 3710 ClassDecl->getVisibleConversionFunctions(); 3711 3712 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 3713 E = Conversions->end(); I != E; ++I) { 3714 NamedDecl *D = I.getDecl(); 3715 if (isa<UsingShadowDecl>(D)) 3716 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 3717 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) { 3718 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3719 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3720 CanTy = ResTypeRef->getPointeeType(); 3721 // Need to go down the pointer/mempointer chain and add qualifiers 3722 // as see them. 3723 bool done = false; 3724 while (!done) { 3725 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3726 CanTy = ResTypePtr->getPointeeType(); 3727 else if (const MemberPointerType *ResTypeMPtr = 3728 CanTy->getAs<MemberPointerType>()) 3729 CanTy = ResTypeMPtr->getPointeeType(); 3730 else 3731 done = true; 3732 if (CanTy.isVolatileQualified()) 3733 VRQuals.addVolatile(); 3734 if (CanTy.isRestrictQualified()) 3735 VRQuals.addRestrict(); 3736 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3737 return VRQuals; 3738 } 3739 } 3740 } 3741 return VRQuals; 3742} 3743 3744/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3745/// operator overloads to the candidate set (C++ [over.built]), based 3746/// on the operator @p Op and the arguments given. For example, if the 3747/// operator is a binary '+', this routine might add "int 3748/// operator+(int, int)" to cover integer addition. 3749void 3750Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3751 SourceLocation OpLoc, 3752 Expr **Args, unsigned NumArgs, 3753 OverloadCandidateSet& CandidateSet) { 3754 // The set of "promoted arithmetic types", which are the arithmetic 3755 // types are that preserved by promotion (C++ [over.built]p2). Note 3756 // that the first few of these types are the promoted integral 3757 // types; these types need to be first. 3758 // FIXME: What about complex? 3759 const unsigned FirstIntegralType = 0; 3760 const unsigned LastIntegralType = 13; 3761 const unsigned FirstPromotedIntegralType = 7, 3762 LastPromotedIntegralType = 13; 3763 const unsigned FirstPromotedArithmeticType = 7, 3764 LastPromotedArithmeticType = 16; 3765 const unsigned NumArithmeticTypes = 16; 3766 QualType ArithmeticTypes[NumArithmeticTypes] = { 3767 Context.BoolTy, Context.CharTy, Context.WCharTy, 3768// FIXME: Context.Char16Ty, Context.Char32Ty, 3769 Context.SignedCharTy, Context.ShortTy, 3770 Context.UnsignedCharTy, Context.UnsignedShortTy, 3771 Context.IntTy, Context.LongTy, Context.LongLongTy, 3772 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 3773 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 3774 }; 3775 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 3776 "Invalid first promoted integral type"); 3777 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 3778 == Context.UnsignedLongLongTy && 3779 "Invalid last promoted integral type"); 3780 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 3781 "Invalid first promoted arithmetic type"); 3782 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 3783 == Context.LongDoubleTy && 3784 "Invalid last promoted arithmetic type"); 3785 3786 // Find all of the types that the arguments can convert to, but only 3787 // if the operator we're looking at has built-in operator candidates 3788 // that make use of these types. 3789 Qualifiers VisibleTypeConversionsQuals; 3790 VisibleTypeConversionsQuals.addConst(); 3791 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3792 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 3793 3794 BuiltinCandidateTypeSet CandidateTypes(*this); 3795 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 3796 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 3797 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 3798 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 3799 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 3800 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 3801 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3802 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 3803 OpLoc, 3804 true, 3805 (Op == OO_Exclaim || 3806 Op == OO_AmpAmp || 3807 Op == OO_PipePipe), 3808 VisibleTypeConversionsQuals); 3809 } 3810 3811 bool isComparison = false; 3812 switch (Op) { 3813 case OO_None: 3814 case NUM_OVERLOADED_OPERATORS: 3815 assert(false && "Expected an overloaded operator"); 3816 break; 3817 3818 case OO_Star: // '*' is either unary or binary 3819 if (NumArgs == 1) 3820 goto UnaryStar; 3821 else 3822 goto BinaryStar; 3823 break; 3824 3825 case OO_Plus: // '+' is either unary or binary 3826 if (NumArgs == 1) 3827 goto UnaryPlus; 3828 else 3829 goto BinaryPlus; 3830 break; 3831 3832 case OO_Minus: // '-' is either unary or binary 3833 if (NumArgs == 1) 3834 goto UnaryMinus; 3835 else 3836 goto BinaryMinus; 3837 break; 3838 3839 case OO_Amp: // '&' is either unary or binary 3840 if (NumArgs == 1) 3841 goto UnaryAmp; 3842 else 3843 goto BinaryAmp; 3844 3845 case OO_PlusPlus: 3846 case OO_MinusMinus: 3847 // C++ [over.built]p3: 3848 // 3849 // For every pair (T, VQ), where T is an arithmetic type, and VQ 3850 // is either volatile or empty, there exist candidate operator 3851 // functions of the form 3852 // 3853 // VQ T& operator++(VQ T&); 3854 // T operator++(VQ T&, int); 3855 // 3856 // C++ [over.built]p4: 3857 // 3858 // For every pair (T, VQ), where T is an arithmetic type other 3859 // than bool, and VQ is either volatile or empty, there exist 3860 // candidate operator functions of the form 3861 // 3862 // VQ T& operator--(VQ T&); 3863 // T operator--(VQ T&, int); 3864 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 3865 Arith < NumArithmeticTypes; ++Arith) { 3866 QualType ArithTy = ArithmeticTypes[Arith]; 3867 QualType ParamTypes[2] 3868 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 3869 3870 // Non-volatile version. 3871 if (NumArgs == 1) 3872 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3873 else 3874 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3875 // heuristic to reduce number of builtin candidates in the set. 3876 // Add volatile version only if there are conversions to a volatile type. 3877 if (VisibleTypeConversionsQuals.hasVolatile()) { 3878 // Volatile version 3879 ParamTypes[0] 3880 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 3881 if (NumArgs == 1) 3882 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3883 else 3884 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3885 } 3886 } 3887 3888 // C++ [over.built]p5: 3889 // 3890 // For every pair (T, VQ), where T is a cv-qualified or 3891 // cv-unqualified object type, and VQ is either volatile or 3892 // empty, there exist candidate operator functions of the form 3893 // 3894 // T*VQ& operator++(T*VQ&); 3895 // T*VQ& operator--(T*VQ&); 3896 // T* operator++(T*VQ&, int); 3897 // T* operator--(T*VQ&, int); 3898 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3899 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3900 // Skip pointer types that aren't pointers to object types. 3901 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 3902 continue; 3903 3904 QualType ParamTypes[2] = { 3905 Context.getLValueReferenceType(*Ptr), Context.IntTy 3906 }; 3907 3908 // Without volatile 3909 if (NumArgs == 1) 3910 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3911 else 3912 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3913 3914 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 3915 VisibleTypeConversionsQuals.hasVolatile()) { 3916 // With volatile 3917 ParamTypes[0] 3918 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 3919 if (NumArgs == 1) 3920 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3921 else 3922 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3923 } 3924 } 3925 break; 3926 3927 UnaryStar: 3928 // C++ [over.built]p6: 3929 // For every cv-qualified or cv-unqualified object type T, there 3930 // exist candidate operator functions of the form 3931 // 3932 // T& operator*(T*); 3933 // 3934 // C++ [over.built]p7: 3935 // For every function type T, there exist candidate operator 3936 // functions of the form 3937 // T& operator*(T*); 3938 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3939 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3940 QualType ParamTy = *Ptr; 3941 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 3942 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 3943 &ParamTy, Args, 1, CandidateSet); 3944 } 3945 break; 3946 3947 UnaryPlus: 3948 // C++ [over.built]p8: 3949 // For every type T, there exist candidate operator functions of 3950 // the form 3951 // 3952 // T* operator+(T*); 3953 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3954 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3955 QualType ParamTy = *Ptr; 3956 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 3957 } 3958 3959 // Fall through 3960 3961 UnaryMinus: 3962 // C++ [over.built]p9: 3963 // For every promoted arithmetic type T, there exist candidate 3964 // operator functions of the form 3965 // 3966 // T operator+(T); 3967 // T operator-(T); 3968 for (unsigned Arith = FirstPromotedArithmeticType; 3969 Arith < LastPromotedArithmeticType; ++Arith) { 3970 QualType ArithTy = ArithmeticTypes[Arith]; 3971 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 3972 } 3973 break; 3974 3975 case OO_Tilde: 3976 // C++ [over.built]p10: 3977 // For every promoted integral type T, there exist candidate 3978 // operator functions of the form 3979 // 3980 // T operator~(T); 3981 for (unsigned Int = FirstPromotedIntegralType; 3982 Int < LastPromotedIntegralType; ++Int) { 3983 QualType IntTy = ArithmeticTypes[Int]; 3984 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 3985 } 3986 break; 3987 3988 case OO_New: 3989 case OO_Delete: 3990 case OO_Array_New: 3991 case OO_Array_Delete: 3992 case OO_Call: 3993 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 3994 break; 3995 3996 case OO_Comma: 3997 UnaryAmp: 3998 case OO_Arrow: 3999 // C++ [over.match.oper]p3: 4000 // -- For the operator ',', the unary operator '&', or the 4001 // operator '->', the built-in candidates set is empty. 4002 break; 4003 4004 case OO_EqualEqual: 4005 case OO_ExclaimEqual: 4006 // C++ [over.match.oper]p16: 4007 // For every pointer to member type T, there exist candidate operator 4008 // functions of the form 4009 // 4010 // bool operator==(T,T); 4011 // bool operator!=(T,T); 4012 for (BuiltinCandidateTypeSet::iterator 4013 MemPtr = CandidateTypes.member_pointer_begin(), 4014 MemPtrEnd = CandidateTypes.member_pointer_end(); 4015 MemPtr != MemPtrEnd; 4016 ++MemPtr) { 4017 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 4018 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4019 } 4020 4021 // Fall through 4022 4023 case OO_Less: 4024 case OO_Greater: 4025 case OO_LessEqual: 4026 case OO_GreaterEqual: 4027 // C++ [over.built]p15: 4028 // 4029 // For every pointer or enumeration type T, there exist 4030 // candidate operator functions of the form 4031 // 4032 // bool operator<(T, T); 4033 // bool operator>(T, T); 4034 // bool operator<=(T, T); 4035 // bool operator>=(T, T); 4036 // bool operator==(T, T); 4037 // bool operator!=(T, T); 4038 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4039 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4040 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4041 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4042 } 4043 for (BuiltinCandidateTypeSet::iterator Enum 4044 = CandidateTypes.enumeration_begin(); 4045 Enum != CandidateTypes.enumeration_end(); ++Enum) { 4046 QualType ParamTypes[2] = { *Enum, *Enum }; 4047 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 4048 } 4049 4050 // Fall through. 4051 isComparison = true; 4052 4053 BinaryPlus: 4054 BinaryMinus: 4055 if (!isComparison) { 4056 // We didn't fall through, so we must have OO_Plus or OO_Minus. 4057 4058 // C++ [over.built]p13: 4059 // 4060 // For every cv-qualified or cv-unqualified object type T 4061 // there exist candidate operator functions of the form 4062 // 4063 // T* operator+(T*, ptrdiff_t); 4064 // T& operator[](T*, ptrdiff_t); [BELOW] 4065 // T* operator-(T*, ptrdiff_t); 4066 // T* operator+(ptrdiff_t, T*); 4067 // T& operator[](ptrdiff_t, T*); [BELOW] 4068 // 4069 // C++ [over.built]p14: 4070 // 4071 // For every T, where T is a pointer to object type, there 4072 // exist candidate operator functions of the form 4073 // 4074 // ptrdiff_t operator-(T, T); 4075 for (BuiltinCandidateTypeSet::iterator Ptr 4076 = CandidateTypes.pointer_begin(); 4077 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4078 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4079 4080 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 4081 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4082 4083 if (Op == OO_Plus) { 4084 // T* operator+(ptrdiff_t, T*); 4085 ParamTypes[0] = ParamTypes[1]; 4086 ParamTypes[1] = *Ptr; 4087 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4088 } else { 4089 // ptrdiff_t operator-(T, T); 4090 ParamTypes[1] = *Ptr; 4091 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 4092 Args, 2, CandidateSet); 4093 } 4094 } 4095 } 4096 // Fall through 4097 4098 case OO_Slash: 4099 BinaryStar: 4100 Conditional: 4101 // C++ [over.built]p12: 4102 // 4103 // For every pair of promoted arithmetic types L and R, there 4104 // exist candidate operator functions of the form 4105 // 4106 // LR operator*(L, R); 4107 // LR operator/(L, R); 4108 // LR operator+(L, R); 4109 // LR operator-(L, R); 4110 // bool operator<(L, R); 4111 // bool operator>(L, R); 4112 // bool operator<=(L, R); 4113 // bool operator>=(L, R); 4114 // bool operator==(L, R); 4115 // bool operator!=(L, R); 4116 // 4117 // where LR is the result of the usual arithmetic conversions 4118 // between types L and R. 4119 // 4120 // C++ [over.built]p24: 4121 // 4122 // For every pair of promoted arithmetic types L and R, there exist 4123 // candidate operator functions of the form 4124 // 4125 // LR operator?(bool, L, R); 4126 // 4127 // where LR is the result of the usual arithmetic conversions 4128 // between types L and R. 4129 // Our candidates ignore the first parameter. 4130 for (unsigned Left = FirstPromotedArithmeticType; 4131 Left < LastPromotedArithmeticType; ++Left) { 4132 for (unsigned Right = FirstPromotedArithmeticType; 4133 Right < LastPromotedArithmeticType; ++Right) { 4134 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4135 QualType Result 4136 = isComparison 4137 ? Context.BoolTy 4138 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4139 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4140 } 4141 } 4142 break; 4143 4144 case OO_Percent: 4145 BinaryAmp: 4146 case OO_Caret: 4147 case OO_Pipe: 4148 case OO_LessLess: 4149 case OO_GreaterGreater: 4150 // C++ [over.built]p17: 4151 // 4152 // For every pair of promoted integral types L and R, there 4153 // exist candidate operator functions of the form 4154 // 4155 // LR operator%(L, R); 4156 // LR operator&(L, R); 4157 // LR operator^(L, R); 4158 // LR operator|(L, R); 4159 // L operator<<(L, R); 4160 // L operator>>(L, R); 4161 // 4162 // where LR is the result of the usual arithmetic conversions 4163 // between types L and R. 4164 for (unsigned Left = FirstPromotedIntegralType; 4165 Left < LastPromotedIntegralType; ++Left) { 4166 for (unsigned Right = FirstPromotedIntegralType; 4167 Right < LastPromotedIntegralType; ++Right) { 4168 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 4169 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 4170 ? LandR[0] 4171 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 4172 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 4173 } 4174 } 4175 break; 4176 4177 case OO_Equal: 4178 // C++ [over.built]p20: 4179 // 4180 // For every pair (T, VQ), where T is an enumeration or 4181 // pointer to member type and VQ is either volatile or 4182 // empty, there exist candidate operator functions of the form 4183 // 4184 // VQ T& operator=(VQ T&, T); 4185 for (BuiltinCandidateTypeSet::iterator 4186 Enum = CandidateTypes.enumeration_begin(), 4187 EnumEnd = CandidateTypes.enumeration_end(); 4188 Enum != EnumEnd; ++Enum) 4189 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 4190 CandidateSet); 4191 for (BuiltinCandidateTypeSet::iterator 4192 MemPtr = CandidateTypes.member_pointer_begin(), 4193 MemPtrEnd = CandidateTypes.member_pointer_end(); 4194 MemPtr != MemPtrEnd; ++MemPtr) 4195 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 4196 CandidateSet); 4197 // Fall through. 4198 4199 case OO_PlusEqual: 4200 case OO_MinusEqual: 4201 // C++ [over.built]p19: 4202 // 4203 // For every pair (T, VQ), where T is any type and VQ is either 4204 // volatile or empty, there exist candidate operator functions 4205 // of the form 4206 // 4207 // T*VQ& operator=(T*VQ&, T*); 4208 // 4209 // C++ [over.built]p21: 4210 // 4211 // For every pair (T, VQ), where T is a cv-qualified or 4212 // cv-unqualified object type and VQ is either volatile or 4213 // empty, there exist candidate operator functions of the form 4214 // 4215 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 4216 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 4217 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4218 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4219 QualType ParamTypes[2]; 4220 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 4221 4222 // non-volatile version 4223 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 4224 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4225 /*IsAssigmentOperator=*/Op == OO_Equal); 4226 4227 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 4228 VisibleTypeConversionsQuals.hasVolatile()) { 4229 // volatile version 4230 ParamTypes[0] 4231 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 4232 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4233 /*IsAssigmentOperator=*/Op == OO_Equal); 4234 } 4235 } 4236 // Fall through. 4237 4238 case OO_StarEqual: 4239 case OO_SlashEqual: 4240 // C++ [over.built]p18: 4241 // 4242 // For every triple (L, VQ, R), where L is an arithmetic type, 4243 // VQ is either volatile or empty, and R is a promoted 4244 // arithmetic type, there exist candidate operator functions of 4245 // the form 4246 // 4247 // VQ L& operator=(VQ L&, R); 4248 // VQ L& operator*=(VQ L&, R); 4249 // VQ L& operator/=(VQ L&, R); 4250 // VQ L& operator+=(VQ L&, R); 4251 // VQ L& operator-=(VQ L&, R); 4252 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 4253 for (unsigned Right = FirstPromotedArithmeticType; 4254 Right < LastPromotedArithmeticType; ++Right) { 4255 QualType ParamTypes[2]; 4256 ParamTypes[1] = ArithmeticTypes[Right]; 4257 4258 // Add this built-in operator as a candidate (VQ is empty). 4259 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4260 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4261 /*IsAssigmentOperator=*/Op == OO_Equal); 4262 4263 // Add this built-in operator as a candidate (VQ is 'volatile'). 4264 if (VisibleTypeConversionsQuals.hasVolatile()) { 4265 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 4266 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4267 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 4268 /*IsAssigmentOperator=*/Op == OO_Equal); 4269 } 4270 } 4271 } 4272 break; 4273 4274 case OO_PercentEqual: 4275 case OO_LessLessEqual: 4276 case OO_GreaterGreaterEqual: 4277 case OO_AmpEqual: 4278 case OO_CaretEqual: 4279 case OO_PipeEqual: 4280 // C++ [over.built]p22: 4281 // 4282 // For every triple (L, VQ, R), where L is an integral type, VQ 4283 // is either volatile or empty, and R is a promoted integral 4284 // type, there exist candidate operator functions of the form 4285 // 4286 // VQ L& operator%=(VQ L&, R); 4287 // VQ L& operator<<=(VQ L&, R); 4288 // VQ L& operator>>=(VQ L&, R); 4289 // VQ L& operator&=(VQ L&, R); 4290 // VQ L& operator^=(VQ L&, R); 4291 // VQ L& operator|=(VQ L&, R); 4292 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 4293 for (unsigned Right = FirstPromotedIntegralType; 4294 Right < LastPromotedIntegralType; ++Right) { 4295 QualType ParamTypes[2]; 4296 ParamTypes[1] = ArithmeticTypes[Right]; 4297 4298 // Add this built-in operator as a candidate (VQ is empty). 4299 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 4300 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4301 if (VisibleTypeConversionsQuals.hasVolatile()) { 4302 // Add this built-in operator as a candidate (VQ is 'volatile'). 4303 ParamTypes[0] = ArithmeticTypes[Left]; 4304 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 4305 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 4306 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 4307 } 4308 } 4309 } 4310 break; 4311 4312 case OO_Exclaim: { 4313 // C++ [over.operator]p23: 4314 // 4315 // There also exist candidate operator functions of the form 4316 // 4317 // bool operator!(bool); 4318 // bool operator&&(bool, bool); [BELOW] 4319 // bool operator||(bool, bool); [BELOW] 4320 QualType ParamTy = Context.BoolTy; 4321 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 4322 /*IsAssignmentOperator=*/false, 4323 /*NumContextualBoolArguments=*/1); 4324 break; 4325 } 4326 4327 case OO_AmpAmp: 4328 case OO_PipePipe: { 4329 // C++ [over.operator]p23: 4330 // 4331 // There also exist candidate operator functions of the form 4332 // 4333 // bool operator!(bool); [ABOVE] 4334 // bool operator&&(bool, bool); 4335 // bool operator||(bool, bool); 4336 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 4337 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 4338 /*IsAssignmentOperator=*/false, 4339 /*NumContextualBoolArguments=*/2); 4340 break; 4341 } 4342 4343 case OO_Subscript: 4344 // C++ [over.built]p13: 4345 // 4346 // For every cv-qualified or cv-unqualified object type T there 4347 // exist candidate operator functions of the form 4348 // 4349 // T* operator+(T*, ptrdiff_t); [ABOVE] 4350 // T& operator[](T*, ptrdiff_t); 4351 // T* operator-(T*, ptrdiff_t); [ABOVE] 4352 // T* operator+(ptrdiff_t, T*); [ABOVE] 4353 // T& operator[](ptrdiff_t, T*); 4354 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 4355 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4356 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 4357 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 4358 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 4359 4360 // T& operator[](T*, ptrdiff_t) 4361 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4362 4363 // T& operator[](ptrdiff_t, T*); 4364 ParamTypes[0] = ParamTypes[1]; 4365 ParamTypes[1] = *Ptr; 4366 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4367 } 4368 break; 4369 4370 case OO_ArrowStar: 4371 // C++ [over.built]p11: 4372 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 4373 // C1 is the same type as C2 or is a derived class of C2, T is an object 4374 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 4375 // there exist candidate operator functions of the form 4376 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 4377 // where CV12 is the union of CV1 and CV2. 4378 { 4379 for (BuiltinCandidateTypeSet::iterator Ptr = 4380 CandidateTypes.pointer_begin(); 4381 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 4382 QualType C1Ty = (*Ptr); 4383 QualType C1; 4384 QualifierCollector Q1; 4385 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 4386 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 4387 if (!isa<RecordType>(C1)) 4388 continue; 4389 // heuristic to reduce number of builtin candidates in the set. 4390 // Add volatile/restrict version only if there are conversions to a 4391 // volatile/restrict type. 4392 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 4393 continue; 4394 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4395 continue; 4396 } 4397 for (BuiltinCandidateTypeSet::iterator 4398 MemPtr = CandidateTypes.member_pointer_begin(), 4399 MemPtrEnd = CandidateTypes.member_pointer_end(); 4400 MemPtr != MemPtrEnd; ++MemPtr) { 4401 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4402 QualType C2 = QualType(mptr->getClass(), 0); 4403 C2 = C2.getUnqualifiedType(); 4404 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4405 break; 4406 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4407 // build CV12 T& 4408 QualType T = mptr->getPointeeType(); 4409 if (!VisibleTypeConversionsQuals.hasVolatile() && 4410 T.isVolatileQualified()) 4411 continue; 4412 if (!VisibleTypeConversionsQuals.hasRestrict() && 4413 T.isRestrictQualified()) 4414 continue; 4415 T = Q1.apply(T); 4416 QualType ResultTy = Context.getLValueReferenceType(T); 4417 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4418 } 4419 } 4420 } 4421 break; 4422 4423 case OO_Conditional: 4424 // Note that we don't consider the first argument, since it has been 4425 // contextually converted to bool long ago. The candidates below are 4426 // therefore added as binary. 4427 // 4428 // C++ [over.built]p24: 4429 // For every type T, where T is a pointer or pointer-to-member type, 4430 // there exist candidate operator functions of the form 4431 // 4432 // T operator?(bool, T, T); 4433 // 4434 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4435 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4436 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4437 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4438 } 4439 for (BuiltinCandidateTypeSet::iterator Ptr = 4440 CandidateTypes.member_pointer_begin(), 4441 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4442 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4443 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4444 } 4445 goto Conditional; 4446 } 4447} 4448 4449/// \brief Add function candidates found via argument-dependent lookup 4450/// to the set of overloading candidates. 4451/// 4452/// This routine performs argument-dependent name lookup based on the 4453/// given function name (which may also be an operator name) and adds 4454/// all of the overload candidates found by ADL to the overload 4455/// candidate set (C++ [basic.lookup.argdep]). 4456void 4457Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4458 bool Operator, 4459 Expr **Args, unsigned NumArgs, 4460 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4461 OverloadCandidateSet& CandidateSet, 4462 bool PartialOverloading) { 4463 ADLResult Fns; 4464 4465 // FIXME: This approach for uniquing ADL results (and removing 4466 // redundant candidates from the set) relies on pointer-equality, 4467 // which means we need to key off the canonical decl. However, 4468 // always going back to the canonical decl might not get us the 4469 // right set of default arguments. What default arguments are 4470 // we supposed to consider on ADL candidates, anyway? 4471 4472 // FIXME: Pass in the explicit template arguments? 4473 ArgumentDependentLookup(Name, Operator, Args, NumArgs, Fns); 4474 4475 // Erase all of the candidates we already knew about. 4476 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4477 CandEnd = CandidateSet.end(); 4478 Cand != CandEnd; ++Cand) 4479 if (Cand->Function) { 4480 Fns.erase(Cand->Function); 4481 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4482 Fns.erase(FunTmpl); 4483 } 4484 4485 // For each of the ADL candidates we found, add it to the overload 4486 // set. 4487 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) { 4488 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none); 4489 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) { 4490 if (ExplicitTemplateArgs) 4491 continue; 4492 4493 AddOverloadCandidate(FD, FoundDecl, Args, NumArgs, CandidateSet, 4494 false, false, PartialOverloading); 4495 } else 4496 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*I), 4497 FoundDecl, ExplicitTemplateArgs, 4498 Args, NumArgs, CandidateSet); 4499 } 4500} 4501 4502/// isBetterOverloadCandidate - Determines whether the first overload 4503/// candidate is a better candidate than the second (C++ 13.3.3p1). 4504bool 4505Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4506 const OverloadCandidate& Cand2, 4507 SourceLocation Loc) { 4508 // Define viable functions to be better candidates than non-viable 4509 // functions. 4510 if (!Cand2.Viable) 4511 return Cand1.Viable; 4512 else if (!Cand1.Viable) 4513 return false; 4514 4515 // C++ [over.match.best]p1: 4516 // 4517 // -- if F is a static member function, ICS1(F) is defined such 4518 // that ICS1(F) is neither better nor worse than ICS1(G) for 4519 // any function G, and, symmetrically, ICS1(G) is neither 4520 // better nor worse than ICS1(F). 4521 unsigned StartArg = 0; 4522 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4523 StartArg = 1; 4524 4525 // C++ [over.match.best]p1: 4526 // A viable function F1 is defined to be a better function than another 4527 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4528 // conversion sequence than ICSi(F2), and then... 4529 unsigned NumArgs = Cand1.Conversions.size(); 4530 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4531 bool HasBetterConversion = false; 4532 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4533 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4534 Cand2.Conversions[ArgIdx])) { 4535 case ImplicitConversionSequence::Better: 4536 // Cand1 has a better conversion sequence. 4537 HasBetterConversion = true; 4538 break; 4539 4540 case ImplicitConversionSequence::Worse: 4541 // Cand1 can't be better than Cand2. 4542 return false; 4543 4544 case ImplicitConversionSequence::Indistinguishable: 4545 // Do nothing. 4546 break; 4547 } 4548 } 4549 4550 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4551 // ICSj(F2), or, if not that, 4552 if (HasBetterConversion) 4553 return true; 4554 4555 // - F1 is a non-template function and F2 is a function template 4556 // specialization, or, if not that, 4557 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4558 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4559 return true; 4560 4561 // -- F1 and F2 are function template specializations, and the function 4562 // template for F1 is more specialized than the template for F2 4563 // according to the partial ordering rules described in 14.5.5.2, or, 4564 // if not that, 4565 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4566 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4567 if (FunctionTemplateDecl *BetterTemplate 4568 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4569 Cand2.Function->getPrimaryTemplate(), 4570 Loc, 4571 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4572 : TPOC_Call)) 4573 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4574 4575 // -- the context is an initialization by user-defined conversion 4576 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4577 // from the return type of F1 to the destination type (i.e., 4578 // the type of the entity being initialized) is a better 4579 // conversion sequence than the standard conversion sequence 4580 // from the return type of F2 to the destination type. 4581 if (Cand1.Function && Cand2.Function && 4582 isa<CXXConversionDecl>(Cand1.Function) && 4583 isa<CXXConversionDecl>(Cand2.Function)) { 4584 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4585 Cand2.FinalConversion)) { 4586 case ImplicitConversionSequence::Better: 4587 // Cand1 has a better conversion sequence. 4588 return true; 4589 4590 case ImplicitConversionSequence::Worse: 4591 // Cand1 can't be better than Cand2. 4592 return false; 4593 4594 case ImplicitConversionSequence::Indistinguishable: 4595 // Do nothing 4596 break; 4597 } 4598 } 4599 4600 return false; 4601} 4602 4603/// \brief Computes the best viable function (C++ 13.3.3) 4604/// within an overload candidate set. 4605/// 4606/// \param CandidateSet the set of candidate functions. 4607/// 4608/// \param Loc the location of the function name (or operator symbol) for 4609/// which overload resolution occurs. 4610/// 4611/// \param Best f overload resolution was successful or found a deleted 4612/// function, Best points to the candidate function found. 4613/// 4614/// \returns The result of overload resolution. 4615OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4616 SourceLocation Loc, 4617 OverloadCandidateSet::iterator& Best) { 4618 // Find the best viable function. 4619 Best = CandidateSet.end(); 4620 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4621 Cand != CandidateSet.end(); ++Cand) { 4622 if (Cand->Viable) { 4623 if (Best == CandidateSet.end() || 4624 isBetterOverloadCandidate(*Cand, *Best, Loc)) 4625 Best = Cand; 4626 } 4627 } 4628 4629 // If we didn't find any viable functions, abort. 4630 if (Best == CandidateSet.end()) 4631 return OR_No_Viable_Function; 4632 4633 // Make sure that this function is better than every other viable 4634 // function. If not, we have an ambiguity. 4635 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4636 Cand != CandidateSet.end(); ++Cand) { 4637 if (Cand->Viable && 4638 Cand != Best && 4639 !isBetterOverloadCandidate(*Best, *Cand, Loc)) { 4640 Best = CandidateSet.end(); 4641 return OR_Ambiguous; 4642 } 4643 } 4644 4645 // Best is the best viable function. 4646 if (Best->Function && 4647 (Best->Function->isDeleted() || 4648 Best->Function->getAttr<UnavailableAttr>())) 4649 return OR_Deleted; 4650 4651 // C++ [basic.def.odr]p2: 4652 // An overloaded function is used if it is selected by overload resolution 4653 // when referred to from a potentially-evaluated expression. [Note: this 4654 // covers calls to named functions (5.2.2), operator overloading 4655 // (clause 13), user-defined conversions (12.3.2), allocation function for 4656 // placement new (5.3.4), as well as non-default initialization (8.5). 4657 if (Best->Function) 4658 MarkDeclarationReferenced(Loc, Best->Function); 4659 return OR_Success; 4660} 4661 4662namespace { 4663 4664enum OverloadCandidateKind { 4665 oc_function, 4666 oc_method, 4667 oc_constructor, 4668 oc_function_template, 4669 oc_method_template, 4670 oc_constructor_template, 4671 oc_implicit_default_constructor, 4672 oc_implicit_copy_constructor, 4673 oc_implicit_copy_assignment 4674}; 4675 4676OverloadCandidateKind ClassifyOverloadCandidate(Sema &S, 4677 FunctionDecl *Fn, 4678 std::string &Description) { 4679 bool isTemplate = false; 4680 4681 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) { 4682 isTemplate = true; 4683 Description = S.getTemplateArgumentBindingsText( 4684 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs()); 4685 } 4686 4687 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4688 if (!Ctor->isImplicit()) 4689 return isTemplate ? oc_constructor_template : oc_constructor; 4690 4691 return Ctor->isCopyConstructor() ? oc_implicit_copy_constructor 4692 : oc_implicit_default_constructor; 4693 } 4694 4695 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4696 // This actually gets spelled 'candidate function' for now, but 4697 // it doesn't hurt to split it out. 4698 if (!Meth->isImplicit()) 4699 return isTemplate ? oc_method_template : oc_method; 4700 4701 assert(Meth->isCopyAssignment() 4702 && "implicit method is not copy assignment operator?"); 4703 return oc_implicit_copy_assignment; 4704 } 4705 4706 return isTemplate ? oc_function_template : oc_function; 4707} 4708 4709} // end anonymous namespace 4710 4711// Notes the location of an overload candidate. 4712void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4713 std::string FnDesc; 4714 OverloadCandidateKind K = ClassifyOverloadCandidate(*this, Fn, FnDesc); 4715 Diag(Fn->getLocation(), diag::note_ovl_candidate) 4716 << (unsigned) K << FnDesc; 4717} 4718 4719/// Diagnoses an ambiguous conversion. The partial diagnostic is the 4720/// "lead" diagnostic; it will be given two arguments, the source and 4721/// target types of the conversion. 4722void Sema::DiagnoseAmbiguousConversion(const ImplicitConversionSequence &ICS, 4723 SourceLocation CaretLoc, 4724 const PartialDiagnostic &PDiag) { 4725 Diag(CaretLoc, PDiag) 4726 << ICS.Ambiguous.getFromType() << ICS.Ambiguous.getToType(); 4727 for (AmbiguousConversionSequence::const_iterator 4728 I = ICS.Ambiguous.begin(), E = ICS.Ambiguous.end(); I != E; ++I) { 4729 NoteOverloadCandidate(*I); 4730 } 4731} 4732 4733namespace { 4734 4735void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand, unsigned I) { 4736 const ImplicitConversionSequence &Conv = Cand->Conversions[I]; 4737 assert(Conv.isBad()); 4738 assert(Cand->Function && "for now, candidate must be a function"); 4739 FunctionDecl *Fn = Cand->Function; 4740 4741 // There's a conversion slot for the object argument if this is a 4742 // non-constructor method. Note that 'I' corresponds the 4743 // conversion-slot index. 4744 bool isObjectArgument = false; 4745 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) { 4746 if (I == 0) 4747 isObjectArgument = true; 4748 else 4749 I--; 4750 } 4751 4752 std::string FnDesc; 4753 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4754 4755 Expr *FromExpr = Conv.Bad.FromExpr; 4756 QualType FromTy = Conv.Bad.getFromType(); 4757 QualType ToTy = Conv.Bad.getToType(); 4758 4759 if (FromTy == S.Context.OverloadTy) { 4760 assert(FromExpr && "overload set argument came from implicit argument?"); 4761 Expr *E = FromExpr->IgnoreParens(); 4762 if (isa<UnaryOperator>(E)) 4763 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens(); 4764 DeclarationName Name = cast<OverloadExpr>(E)->getName(); 4765 4766 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload) 4767 << (unsigned) FnKind << FnDesc 4768 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4769 << ToTy << Name << I+1; 4770 return; 4771 } 4772 4773 // Do some hand-waving analysis to see if the non-viability is due 4774 // to a qualifier mismatch. 4775 CanQualType CFromTy = S.Context.getCanonicalType(FromTy); 4776 CanQualType CToTy = S.Context.getCanonicalType(ToTy); 4777 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>()) 4778 CToTy = RT->getPointeeType(); 4779 else { 4780 // TODO: detect and diagnose the full richness of const mismatches. 4781 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>()) 4782 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) 4783 CFromTy = FromPT->getPointeeType(), CToTy = ToPT->getPointeeType(); 4784 } 4785 4786 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() && 4787 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) { 4788 // It is dumb that we have to do this here. 4789 while (isa<ArrayType>(CFromTy)) 4790 CFromTy = CFromTy->getAs<ArrayType>()->getElementType(); 4791 while (isa<ArrayType>(CToTy)) 4792 CToTy = CFromTy->getAs<ArrayType>()->getElementType(); 4793 4794 Qualifiers FromQs = CFromTy.getQualifiers(); 4795 Qualifiers ToQs = CToTy.getQualifiers(); 4796 4797 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) { 4798 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace) 4799 << (unsigned) FnKind << FnDesc 4800 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4801 << FromTy 4802 << FromQs.getAddressSpace() << ToQs.getAddressSpace() 4803 << (unsigned) isObjectArgument << I+1; 4804 return; 4805 } 4806 4807 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers(); 4808 assert(CVR && "unexpected qualifiers mismatch"); 4809 4810 if (isObjectArgument) { 4811 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this) 4812 << (unsigned) FnKind << FnDesc 4813 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4814 << FromTy << (CVR - 1); 4815 } else { 4816 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr) 4817 << (unsigned) FnKind << FnDesc 4818 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4819 << FromTy << (CVR - 1) << I+1; 4820 } 4821 return; 4822 } 4823 4824 // Diagnose references or pointers to incomplete types differently, 4825 // since it's far from impossible that the incompleteness triggered 4826 // the failure. 4827 QualType TempFromTy = FromTy.getNonReferenceType(); 4828 if (const PointerType *PTy = TempFromTy->getAs<PointerType>()) 4829 TempFromTy = PTy->getPointeeType(); 4830 if (TempFromTy->isIncompleteType()) { 4831 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete) 4832 << (unsigned) FnKind << FnDesc 4833 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4834 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4835 return; 4836 } 4837 4838 // TODO: specialize more based on the kind of mismatch 4839 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv) 4840 << (unsigned) FnKind << FnDesc 4841 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) 4842 << FromTy << ToTy << (unsigned) isObjectArgument << I+1; 4843} 4844 4845void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand, 4846 unsigned NumFormalArgs) { 4847 // TODO: treat calls to a missing default constructor as a special case 4848 4849 FunctionDecl *Fn = Cand->Function; 4850 const FunctionProtoType *FnTy = Fn->getType()->getAs<FunctionProtoType>(); 4851 4852 unsigned MinParams = Fn->getMinRequiredArguments(); 4853 4854 // at least / at most / exactly 4855 unsigned mode, modeCount; 4856 if (NumFormalArgs < MinParams) { 4857 assert(Cand->FailureKind == ovl_fail_too_few_arguments); 4858 if (MinParams != FnTy->getNumArgs() || FnTy->isVariadic()) 4859 mode = 0; // "at least" 4860 else 4861 mode = 2; // "exactly" 4862 modeCount = MinParams; 4863 } else { 4864 assert(Cand->FailureKind == ovl_fail_too_many_arguments); 4865 if (MinParams != FnTy->getNumArgs()) 4866 mode = 1; // "at most" 4867 else 4868 mode = 2; // "exactly" 4869 modeCount = FnTy->getNumArgs(); 4870 } 4871 4872 std::string Description; 4873 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, Description); 4874 4875 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity) 4876 << (unsigned) FnKind << Description << mode << modeCount << NumFormalArgs; 4877} 4878 4879/// Diagnose a failed template-argument deduction. 4880void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand, 4881 Expr **Args, unsigned NumArgs) { 4882 FunctionDecl *Fn = Cand->Function; // pattern 4883 4884 TemplateParameter Param = TemplateParameter::getFromOpaqueValue( 4885 Cand->DeductionFailure.TemplateParameter); 4886 4887 switch (Cand->DeductionFailure.Result) { 4888 case Sema::TDK_Success: 4889 llvm_unreachable("TDK_success while diagnosing bad deduction"); 4890 4891 case Sema::TDK_Incomplete: { 4892 NamedDecl *ParamD; 4893 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) || 4894 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) || 4895 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>()); 4896 assert(ParamD && "no parameter found for incomplete deduction result"); 4897 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_incomplete_deduction) 4898 << ParamD->getDeclName(); 4899 return; 4900 } 4901 4902 // TODO: diagnose these individually, then kill off 4903 // note_ovl_candidate_bad_deduction, which is uselessly vague. 4904 case Sema::TDK_InstantiationDepth: 4905 case Sema::TDK_Inconsistent: 4906 case Sema::TDK_InconsistentQuals: 4907 case Sema::TDK_SubstitutionFailure: 4908 case Sema::TDK_NonDeducedMismatch: 4909 case Sema::TDK_TooManyArguments: 4910 case Sema::TDK_TooFewArguments: 4911 case Sema::TDK_InvalidExplicitArguments: 4912 case Sema::TDK_FailedOverloadResolution: 4913 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_deduction); 4914 return; 4915 } 4916} 4917 4918/// Generates a 'note' diagnostic for an overload candidate. We've 4919/// already generated a primary error at the call site. 4920/// 4921/// It really does need to be a single diagnostic with its caret 4922/// pointed at the candidate declaration. Yes, this creates some 4923/// major challenges of technical writing. Yes, this makes pointing 4924/// out problems with specific arguments quite awkward. It's still 4925/// better than generating twenty screens of text for every failed 4926/// overload. 4927/// 4928/// It would be great to be able to express per-candidate problems 4929/// more richly for those diagnostic clients that cared, but we'd 4930/// still have to be just as careful with the default diagnostics. 4931void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand, 4932 Expr **Args, unsigned NumArgs) { 4933 FunctionDecl *Fn = Cand->Function; 4934 4935 // Note deleted candidates, but only if they're viable. 4936 if (Cand->Viable && (Fn->isDeleted() || Fn->hasAttr<UnavailableAttr>())) { 4937 std::string FnDesc; 4938 OverloadCandidateKind FnKind = ClassifyOverloadCandidate(S, Fn, FnDesc); 4939 4940 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted) 4941 << FnKind << FnDesc << Fn->isDeleted(); 4942 return; 4943 } 4944 4945 // We don't really have anything else to say about viable candidates. 4946 if (Cand->Viable) { 4947 S.NoteOverloadCandidate(Fn); 4948 return; 4949 } 4950 4951 switch (Cand->FailureKind) { 4952 case ovl_fail_too_many_arguments: 4953 case ovl_fail_too_few_arguments: 4954 return DiagnoseArityMismatch(S, Cand, NumArgs); 4955 4956 case ovl_fail_bad_deduction: 4957 return DiagnoseBadDeduction(S, Cand, Args, NumArgs); 4958 4959 case ovl_fail_trivial_conversion: 4960 case ovl_fail_bad_final_conversion: 4961 case ovl_fail_final_conversion_not_exact: 4962 return S.NoteOverloadCandidate(Fn); 4963 4964 case ovl_fail_bad_conversion: { 4965 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0); 4966 for (unsigned N = Cand->Conversions.size(); I != N; ++I) 4967 if (Cand->Conversions[I].isBad()) 4968 return DiagnoseBadConversion(S, Cand, I); 4969 4970 // FIXME: this currently happens when we're called from SemaInit 4971 // when user-conversion overload fails. Figure out how to handle 4972 // those conditions and diagnose them well. 4973 return S.NoteOverloadCandidate(Fn); 4974 } 4975 } 4976} 4977 4978void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 4979 // Desugar the type of the surrogate down to a function type, 4980 // retaining as many typedefs as possible while still showing 4981 // the function type (and, therefore, its parameter types). 4982 QualType FnType = Cand->Surrogate->getConversionType(); 4983 bool isLValueReference = false; 4984 bool isRValueReference = false; 4985 bool isPointer = false; 4986 if (const LValueReferenceType *FnTypeRef = 4987 FnType->getAs<LValueReferenceType>()) { 4988 FnType = FnTypeRef->getPointeeType(); 4989 isLValueReference = true; 4990 } else if (const RValueReferenceType *FnTypeRef = 4991 FnType->getAs<RValueReferenceType>()) { 4992 FnType = FnTypeRef->getPointeeType(); 4993 isRValueReference = true; 4994 } 4995 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 4996 FnType = FnTypePtr->getPointeeType(); 4997 isPointer = true; 4998 } 4999 // Desugar down to a function type. 5000 FnType = QualType(FnType->getAs<FunctionType>(), 0); 5001 // Reconstruct the pointer/reference as appropriate. 5002 if (isPointer) FnType = S.Context.getPointerType(FnType); 5003 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 5004 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 5005 5006 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 5007 << FnType; 5008} 5009 5010void NoteBuiltinOperatorCandidate(Sema &S, 5011 const char *Opc, 5012 SourceLocation OpLoc, 5013 OverloadCandidate *Cand) { 5014 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 5015 std::string TypeStr("operator"); 5016 TypeStr += Opc; 5017 TypeStr += "("; 5018 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 5019 if (Cand->Conversions.size() == 1) { 5020 TypeStr += ")"; 5021 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 5022 } else { 5023 TypeStr += ", "; 5024 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 5025 TypeStr += ")"; 5026 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 5027 } 5028} 5029 5030void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 5031 OverloadCandidate *Cand) { 5032 unsigned NoOperands = Cand->Conversions.size(); 5033 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 5034 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 5035 if (ICS.isBad()) break; // all meaningless after first invalid 5036 if (!ICS.isAmbiguous()) continue; 5037 5038 S.DiagnoseAmbiguousConversion(ICS, OpLoc, 5039 S.PDiag(diag::note_ambiguous_type_conversion)); 5040 } 5041} 5042 5043SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) { 5044 if (Cand->Function) 5045 return Cand->Function->getLocation(); 5046 if (Cand->IsSurrogate) 5047 return Cand->Surrogate->getLocation(); 5048 return SourceLocation(); 5049} 5050 5051struct CompareOverloadCandidatesForDisplay { 5052 Sema &S; 5053 CompareOverloadCandidatesForDisplay(Sema &S) : S(S) {} 5054 5055 bool operator()(const OverloadCandidate *L, 5056 const OverloadCandidate *R) { 5057 // Fast-path this check. 5058 if (L == R) return false; 5059 5060 // Order first by viability. 5061 if (L->Viable) { 5062 if (!R->Viable) return true; 5063 5064 // TODO: introduce a tri-valued comparison for overload 5065 // candidates. Would be more worthwhile if we had a sort 5066 // that could exploit it. 5067 if (S.isBetterOverloadCandidate(*L, *R, SourceLocation())) return true; 5068 if (S.isBetterOverloadCandidate(*R, *L, SourceLocation())) return false; 5069 } else if (R->Viable) 5070 return false; 5071 5072 assert(L->Viable == R->Viable); 5073 5074 // Criteria by which we can sort non-viable candidates: 5075 if (!L->Viable) { 5076 // 1. Arity mismatches come after other candidates. 5077 if (L->FailureKind == ovl_fail_too_many_arguments || 5078 L->FailureKind == ovl_fail_too_few_arguments) 5079 return false; 5080 if (R->FailureKind == ovl_fail_too_many_arguments || 5081 R->FailureKind == ovl_fail_too_few_arguments) 5082 return true; 5083 5084 // 2. Bad conversions come first and are ordered by the number 5085 // of bad conversions and quality of good conversions. 5086 if (L->FailureKind == ovl_fail_bad_conversion) { 5087 if (R->FailureKind != ovl_fail_bad_conversion) 5088 return true; 5089 5090 // If there's any ordering between the defined conversions... 5091 // FIXME: this might not be transitive. 5092 assert(L->Conversions.size() == R->Conversions.size()); 5093 5094 int leftBetter = 0; 5095 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument); 5096 for (unsigned E = L->Conversions.size(); I != E; ++I) { 5097 switch (S.CompareImplicitConversionSequences(L->Conversions[I], 5098 R->Conversions[I])) { 5099 case ImplicitConversionSequence::Better: 5100 leftBetter++; 5101 break; 5102 5103 case ImplicitConversionSequence::Worse: 5104 leftBetter--; 5105 break; 5106 5107 case ImplicitConversionSequence::Indistinguishable: 5108 break; 5109 } 5110 } 5111 if (leftBetter > 0) return true; 5112 if (leftBetter < 0) return false; 5113 5114 } else if (R->FailureKind == ovl_fail_bad_conversion) 5115 return false; 5116 5117 // TODO: others? 5118 } 5119 5120 // Sort everything else by location. 5121 SourceLocation LLoc = GetLocationForCandidate(L); 5122 SourceLocation RLoc = GetLocationForCandidate(R); 5123 5124 // Put candidates without locations (e.g. builtins) at the end. 5125 if (LLoc.isInvalid()) return false; 5126 if (RLoc.isInvalid()) return true; 5127 5128 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc); 5129 } 5130}; 5131 5132/// CompleteNonViableCandidate - Normally, overload resolution only 5133/// computes up to the first 5134void CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand, 5135 Expr **Args, unsigned NumArgs) { 5136 assert(!Cand->Viable); 5137 5138 // Don't do anything on failures other than bad conversion. 5139 if (Cand->FailureKind != ovl_fail_bad_conversion) return; 5140 5141 // Skip forward to the first bad conversion. 5142 unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); 5143 unsigned ConvCount = Cand->Conversions.size(); 5144 while (true) { 5145 assert(ConvIdx != ConvCount && "no bad conversion in candidate"); 5146 ConvIdx++; 5147 if (Cand->Conversions[ConvIdx - 1].isBad()) 5148 break; 5149 } 5150 5151 if (ConvIdx == ConvCount) 5152 return; 5153 5154 assert(!Cand->Conversions[ConvIdx].isInitialized() && 5155 "remaining conversion is initialized?"); 5156 5157 // FIXME: these should probably be preserved from the overload 5158 // operation somehow. 5159 bool SuppressUserConversions = false; 5160 bool ForceRValue = false; 5161 5162 const FunctionProtoType* Proto; 5163 unsigned ArgIdx = ConvIdx; 5164 5165 if (Cand->IsSurrogate) { 5166 QualType ConvType 5167 = Cand->Surrogate->getConversionType().getNonReferenceType(); 5168 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5169 ConvType = ConvPtrType->getPointeeType(); 5170 Proto = ConvType->getAs<FunctionProtoType>(); 5171 ArgIdx--; 5172 } else if (Cand->Function) { 5173 Proto = Cand->Function->getType()->getAs<FunctionProtoType>(); 5174 if (isa<CXXMethodDecl>(Cand->Function) && 5175 !isa<CXXConstructorDecl>(Cand->Function)) 5176 ArgIdx--; 5177 } else { 5178 // Builtin binary operator with a bad first conversion. 5179 assert(ConvCount <= 3); 5180 for (; ConvIdx != ConvCount; ++ConvIdx) 5181 Cand->Conversions[ConvIdx] 5182 = S.TryCopyInitialization(Args[ConvIdx], 5183 Cand->BuiltinTypes.ParamTypes[ConvIdx], 5184 SuppressUserConversions, ForceRValue, 5185 /*InOverloadResolution*/ true); 5186 return; 5187 } 5188 5189 // Fill in the rest of the conversions. 5190 unsigned NumArgsInProto = Proto->getNumArgs(); 5191 for (; ConvIdx != ConvCount; ++ConvIdx, ++ArgIdx) { 5192 if (ArgIdx < NumArgsInProto) 5193 Cand->Conversions[ConvIdx] 5194 = S.TryCopyInitialization(Args[ArgIdx], Proto->getArgType(ArgIdx), 5195 SuppressUserConversions, ForceRValue, 5196 /*InOverloadResolution=*/true); 5197 else 5198 Cand->Conversions[ConvIdx].setEllipsis(); 5199 } 5200} 5201 5202} // end anonymous namespace 5203 5204/// PrintOverloadCandidates - When overload resolution fails, prints 5205/// diagnostic messages containing the candidates in the candidate 5206/// set. 5207void 5208Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 5209 OverloadCandidateDisplayKind OCD, 5210 Expr **Args, unsigned NumArgs, 5211 const char *Opc, 5212 SourceLocation OpLoc) { 5213 // Sort the candidates by viability and position. Sorting directly would 5214 // be prohibitive, so we make a set of pointers and sort those. 5215 llvm::SmallVector<OverloadCandidate*, 32> Cands; 5216 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 5217 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 5218 LastCand = CandidateSet.end(); 5219 Cand != LastCand; ++Cand) { 5220 if (Cand->Viable) 5221 Cands.push_back(Cand); 5222 else if (OCD == OCD_AllCandidates) { 5223 CompleteNonViableCandidate(*this, Cand, Args, NumArgs); 5224 Cands.push_back(Cand); 5225 } 5226 } 5227 5228 std::sort(Cands.begin(), Cands.end(), 5229 CompareOverloadCandidatesForDisplay(*this)); 5230 5231 bool ReportedAmbiguousConversions = false; 5232 5233 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 5234 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 5235 OverloadCandidate *Cand = *I; 5236 5237 if (Cand->Function) 5238 NoteFunctionCandidate(*this, Cand, Args, NumArgs); 5239 else if (Cand->IsSurrogate) 5240 NoteSurrogateCandidate(*this, Cand); 5241 5242 // This a builtin candidate. We do not, in general, want to list 5243 // every possible builtin candidate. 5244 else if (Cand->Viable) { 5245 // Generally we only see ambiguities including viable builtin 5246 // operators if overload resolution got screwed up by an 5247 // ambiguous user-defined conversion. 5248 // 5249 // FIXME: It's quite possible for different conversions to see 5250 // different ambiguities, though. 5251 if (!ReportedAmbiguousConversions) { 5252 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 5253 ReportedAmbiguousConversions = true; 5254 } 5255 5256 // If this is a viable builtin, print it. 5257 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 5258 } 5259 } 5260} 5261 5262static bool CheckUnresolvedAccess(Sema &S, OverloadExpr *E, DeclAccessPair D) { 5263 if (isa<UnresolvedLookupExpr>(E)) 5264 return S.CheckUnresolvedLookupAccess(cast<UnresolvedLookupExpr>(E), D); 5265 5266 return S.CheckUnresolvedMemberAccess(cast<UnresolvedMemberExpr>(E), D); 5267} 5268 5269/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 5270/// an overloaded function (C++ [over.over]), where @p From is an 5271/// expression with overloaded function type and @p ToType is the type 5272/// we're trying to resolve to. For example: 5273/// 5274/// @code 5275/// int f(double); 5276/// int f(int); 5277/// 5278/// int (*pfd)(double) = f; // selects f(double) 5279/// @endcode 5280/// 5281/// This routine returns the resulting FunctionDecl if it could be 5282/// resolved, and NULL otherwise. When @p Complain is true, this 5283/// routine will emit diagnostics if there is an error. 5284FunctionDecl * 5285Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 5286 bool Complain, 5287 DeclAccessPair &FoundResult) { 5288 QualType FunctionType = ToType; 5289 bool IsMember = false; 5290 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 5291 FunctionType = ToTypePtr->getPointeeType(); 5292 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 5293 FunctionType = ToTypeRef->getPointeeType(); 5294 else if (const MemberPointerType *MemTypePtr = 5295 ToType->getAs<MemberPointerType>()) { 5296 FunctionType = MemTypePtr->getPointeeType(); 5297 IsMember = true; 5298 } 5299 5300 // C++ [over.over]p1: 5301 // [...] [Note: any redundant set of parentheses surrounding the 5302 // overloaded function name is ignored (5.1). ] 5303 // C++ [over.over]p1: 5304 // [...] The overloaded function name can be preceded by the & 5305 // operator. 5306 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5307 TemplateArgumentListInfo ETABuffer, *ExplicitTemplateArgs = 0; 5308 if (OvlExpr->hasExplicitTemplateArgs()) { 5309 OvlExpr->getExplicitTemplateArgs().copyInto(ETABuffer); 5310 ExplicitTemplateArgs = &ETABuffer; 5311 } 5312 5313 // We expect a pointer or reference to function, or a function pointer. 5314 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 5315 if (!FunctionType->isFunctionType()) { 5316 if (Complain) 5317 Diag(From->getLocStart(), diag::err_addr_ovl_not_func_ptrref) 5318 << OvlExpr->getName() << ToType; 5319 5320 return 0; 5321 } 5322 5323 assert(From->getType() == Context.OverloadTy); 5324 5325 // Look through all of the overloaded functions, searching for one 5326 // whose type matches exactly. 5327 llvm::SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches; 5328 llvm::SmallVector<FunctionDecl *, 4> NonMatches; 5329 5330 bool FoundNonTemplateFunction = false; 5331 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5332 E = OvlExpr->decls_end(); I != E; ++I) { 5333 // Look through any using declarations to find the underlying function. 5334 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 5335 5336 // C++ [over.over]p3: 5337 // Non-member functions and static member functions match 5338 // targets of type "pointer-to-function" or "reference-to-function." 5339 // Nonstatic member functions match targets of 5340 // type "pointer-to-member-function." 5341 // Note that according to DR 247, the containing class does not matter. 5342 5343 if (FunctionTemplateDecl *FunctionTemplate 5344 = dyn_cast<FunctionTemplateDecl>(Fn)) { 5345 if (CXXMethodDecl *Method 5346 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 5347 // Skip non-static function templates when converting to pointer, and 5348 // static when converting to member pointer. 5349 if (Method->isStatic() == IsMember) 5350 continue; 5351 } else if (IsMember) 5352 continue; 5353 5354 // C++ [over.over]p2: 5355 // If the name is a function template, template argument deduction is 5356 // done (14.8.2.2), and if the argument deduction succeeds, the 5357 // resulting template argument list is used to generate a single 5358 // function template specialization, which is added to the set of 5359 // overloaded functions considered. 5360 // FIXME: We don't really want to build the specialization here, do we? 5361 FunctionDecl *Specialization = 0; 5362 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5363 if (TemplateDeductionResult Result 5364 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 5365 FunctionType, Specialization, Info)) { 5366 // FIXME: make a note of the failed deduction for diagnostics. 5367 (void)Result; 5368 } else { 5369 // FIXME: If the match isn't exact, shouldn't we just drop this as 5370 // a candidate? Find a testcase before changing the code. 5371 assert(FunctionType 5372 == Context.getCanonicalType(Specialization->getType())); 5373 Matches.push_back(std::make_pair(I.getPair(), 5374 cast<FunctionDecl>(Specialization->getCanonicalDecl()))); 5375 } 5376 5377 continue; 5378 } 5379 5380 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 5381 // Skip non-static functions when converting to pointer, and static 5382 // when converting to member pointer. 5383 if (Method->isStatic() == IsMember) 5384 continue; 5385 5386 // If we have explicit template arguments, skip non-templates. 5387 if (OvlExpr->hasExplicitTemplateArgs()) 5388 continue; 5389 } else if (IsMember) 5390 continue; 5391 5392 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 5393 QualType ResultTy; 5394 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 5395 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 5396 ResultTy)) { 5397 Matches.push_back(std::make_pair(I.getPair(), 5398 cast<FunctionDecl>(FunDecl->getCanonicalDecl()))); 5399 FoundNonTemplateFunction = true; 5400 } 5401 } 5402 } 5403 5404 // If there were 0 or 1 matches, we're done. 5405 if (Matches.empty()) { 5406 if (Complain) { 5407 Diag(From->getLocStart(), diag::err_addr_ovl_no_viable) 5408 << OvlExpr->getName() << FunctionType; 5409 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5410 E = OvlExpr->decls_end(); 5411 I != E; ++I) 5412 if (FunctionDecl *F = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl())) 5413 NoteOverloadCandidate(F); 5414 } 5415 5416 return 0; 5417 } else if (Matches.size() == 1) { 5418 FunctionDecl *Result = Matches[0].second; 5419 FoundResult = Matches[0].first; 5420 MarkDeclarationReferenced(From->getLocStart(), Result); 5421 if (Complain) 5422 CheckAddressOfMemberAccess(OvlExpr, Matches[0].first); 5423 return Result; 5424 } 5425 5426 // C++ [over.over]p4: 5427 // If more than one function is selected, [...] 5428 if (!FoundNonTemplateFunction) { 5429 // [...] and any given function template specialization F1 is 5430 // eliminated if the set contains a second function template 5431 // specialization whose function template is more specialized 5432 // than the function template of F1 according to the partial 5433 // ordering rules of 14.5.5.2. 5434 5435 // The algorithm specified above is quadratic. We instead use a 5436 // two-pass algorithm (similar to the one used to identify the 5437 // best viable function in an overload set) that identifies the 5438 // best function template (if it exists). 5439 5440 UnresolvedSet<4> MatchesCopy; // TODO: avoid! 5441 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5442 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess()); 5443 5444 UnresolvedSetIterator Result = 5445 getMostSpecialized(MatchesCopy.begin(), MatchesCopy.end(), 5446 TPOC_Other, From->getLocStart(), 5447 PDiag(), 5448 PDiag(diag::err_addr_ovl_ambiguous) 5449 << Matches[0].second->getDeclName(), 5450 PDiag(diag::note_ovl_candidate) 5451 << (unsigned) oc_function_template); 5452 assert(Result != MatchesCopy.end() && "no most-specialized template"); 5453 MarkDeclarationReferenced(From->getLocStart(), *Result); 5454 FoundResult = Matches[Result - MatchesCopy.begin()].first; 5455 if (Complain) 5456 CheckUnresolvedAccess(*this, OvlExpr, FoundResult); 5457 return cast<FunctionDecl>(*Result); 5458 } 5459 5460 // [...] any function template specializations in the set are 5461 // eliminated if the set also contains a non-template function, [...] 5462 for (unsigned I = 0, N = Matches.size(); I != N; ) { 5463 if (Matches[I].second->getPrimaryTemplate() == 0) 5464 ++I; 5465 else { 5466 Matches[I] = Matches[--N]; 5467 Matches.set_size(N); 5468 } 5469 } 5470 5471 // [...] After such eliminations, if any, there shall remain exactly one 5472 // selected function. 5473 if (Matches.size() == 1) { 5474 MarkDeclarationReferenced(From->getLocStart(), Matches[0].second); 5475 FoundResult = Matches[0].first; 5476 if (Complain) 5477 CheckUnresolvedAccess(*this, OvlExpr, Matches[0].first); 5478 return cast<FunctionDecl>(Matches[0].second); 5479 } 5480 5481 // FIXME: We should probably return the same thing that BestViableFunction 5482 // returns (even if we issue the diagnostics here). 5483 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 5484 << Matches[0].second->getDeclName(); 5485 for (unsigned I = 0, E = Matches.size(); I != E; ++I) 5486 NoteOverloadCandidate(Matches[I].second); 5487 return 0; 5488} 5489 5490/// \brief Given an expression that refers to an overloaded function, try to 5491/// resolve that overloaded function expression down to a single function. 5492/// 5493/// This routine can only resolve template-ids that refer to a single function 5494/// template, where that template-id refers to a single template whose template 5495/// arguments are either provided by the template-id or have defaults, 5496/// as described in C++0x [temp.arg.explicit]p3. 5497FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 5498 // C++ [over.over]p1: 5499 // [...] [Note: any redundant set of parentheses surrounding the 5500 // overloaded function name is ignored (5.1). ] 5501 // C++ [over.over]p1: 5502 // [...] The overloaded function name can be preceded by the & 5503 // operator. 5504 5505 if (From->getType() != Context.OverloadTy) 5506 return 0; 5507 5508 OverloadExpr *OvlExpr = OverloadExpr::find(From).getPointer(); 5509 5510 // If we didn't actually find any template-ids, we're done. 5511 if (!OvlExpr->hasExplicitTemplateArgs()) 5512 return 0; 5513 5514 TemplateArgumentListInfo ExplicitTemplateArgs; 5515 OvlExpr->getExplicitTemplateArgs().copyInto(ExplicitTemplateArgs); 5516 5517 // Look through all of the overloaded functions, searching for one 5518 // whose type matches exactly. 5519 FunctionDecl *Matched = 0; 5520 for (UnresolvedSetIterator I = OvlExpr->decls_begin(), 5521 E = OvlExpr->decls_end(); I != E; ++I) { 5522 // C++0x [temp.arg.explicit]p3: 5523 // [...] In contexts where deduction is done and fails, or in contexts 5524 // where deduction is not done, if a template argument list is 5525 // specified and it, along with any default template arguments, 5526 // identifies a single function template specialization, then the 5527 // template-id is an lvalue for the function template specialization. 5528 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 5529 5530 // C++ [over.over]p2: 5531 // If the name is a function template, template argument deduction is 5532 // done (14.8.2.2), and if the argument deduction succeeds, the 5533 // resulting template argument list is used to generate a single 5534 // function template specialization, which is added to the set of 5535 // overloaded functions considered. 5536 FunctionDecl *Specialization = 0; 5537 TemplateDeductionInfo Info(Context, OvlExpr->getNameLoc()); 5538 if (TemplateDeductionResult Result 5539 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 5540 Specialization, Info)) { 5541 // FIXME: make a note of the failed deduction for diagnostics. 5542 (void)Result; 5543 continue; 5544 } 5545 5546 // Multiple matches; we can't resolve to a single declaration. 5547 if (Matched) 5548 return 0; 5549 5550 Matched = Specialization; 5551 } 5552 5553 return Matched; 5554} 5555 5556/// \brief Add a single candidate to the overload set. 5557static void AddOverloadedCallCandidate(Sema &S, 5558 DeclAccessPair FoundDecl, 5559 const TemplateArgumentListInfo *ExplicitTemplateArgs, 5560 Expr **Args, unsigned NumArgs, 5561 OverloadCandidateSet &CandidateSet, 5562 bool PartialOverloading) { 5563 NamedDecl *Callee = FoundDecl.getDecl(); 5564 if (isa<UsingShadowDecl>(Callee)) 5565 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 5566 5567 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 5568 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 5569 S.AddOverloadCandidate(Func, FoundDecl, Args, NumArgs, CandidateSet, 5570 false, false, PartialOverloading); 5571 return; 5572 } 5573 5574 if (FunctionTemplateDecl *FuncTemplate 5575 = dyn_cast<FunctionTemplateDecl>(Callee)) { 5576 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl, 5577 ExplicitTemplateArgs, 5578 Args, NumArgs, CandidateSet); 5579 return; 5580 } 5581 5582 assert(false && "unhandled case in overloaded call candidate"); 5583 5584 // do nothing? 5585} 5586 5587/// \brief Add the overload candidates named by callee and/or found by argument 5588/// dependent lookup to the given overload set. 5589void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 5590 Expr **Args, unsigned NumArgs, 5591 OverloadCandidateSet &CandidateSet, 5592 bool PartialOverloading) { 5593 5594#ifndef NDEBUG 5595 // Verify that ArgumentDependentLookup is consistent with the rules 5596 // in C++0x [basic.lookup.argdep]p3: 5597 // 5598 // Let X be the lookup set produced by unqualified lookup (3.4.1) 5599 // and let Y be the lookup set produced by argument dependent 5600 // lookup (defined as follows). If X contains 5601 // 5602 // -- a declaration of a class member, or 5603 // 5604 // -- a block-scope function declaration that is not a 5605 // using-declaration, or 5606 // 5607 // -- a declaration that is neither a function or a function 5608 // template 5609 // 5610 // then Y is empty. 5611 5612 if (ULE->requiresADL()) { 5613 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5614 E = ULE->decls_end(); I != E; ++I) { 5615 assert(!(*I)->getDeclContext()->isRecord()); 5616 assert(isa<UsingShadowDecl>(*I) || 5617 !(*I)->getDeclContext()->isFunctionOrMethod()); 5618 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 5619 } 5620 } 5621#endif 5622 5623 // It would be nice to avoid this copy. 5624 TemplateArgumentListInfo TABuffer; 5625 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5626 if (ULE->hasExplicitTemplateArgs()) { 5627 ULE->copyTemplateArgumentsInto(TABuffer); 5628 ExplicitTemplateArgs = &TABuffer; 5629 } 5630 5631 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 5632 E = ULE->decls_end(); I != E; ++I) 5633 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, 5634 Args, NumArgs, CandidateSet, 5635 PartialOverloading); 5636 5637 if (ULE->requiresADL()) 5638 AddArgumentDependentLookupCandidates(ULE->getName(), /*Operator*/ false, 5639 Args, NumArgs, 5640 ExplicitTemplateArgs, 5641 CandidateSet, 5642 PartialOverloading); 5643} 5644 5645static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 5646 Expr **Args, unsigned NumArgs) { 5647 Fn->Destroy(SemaRef.Context); 5648 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5649 Args[Arg]->Destroy(SemaRef.Context); 5650 return SemaRef.ExprError(); 5651} 5652 5653/// Attempts to recover from a call where no functions were found. 5654/// 5655/// Returns true if new candidates were found. 5656static Sema::OwningExprResult 5657BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn, 5658 UnresolvedLookupExpr *ULE, 5659 SourceLocation LParenLoc, 5660 Expr **Args, unsigned NumArgs, 5661 SourceLocation *CommaLocs, 5662 SourceLocation RParenLoc) { 5663 5664 CXXScopeSpec SS; 5665 if (ULE->getQualifier()) { 5666 SS.setScopeRep(ULE->getQualifier()); 5667 SS.setRange(ULE->getQualifierRange()); 5668 } 5669 5670 TemplateArgumentListInfo TABuffer; 5671 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 5672 if (ULE->hasExplicitTemplateArgs()) { 5673 ULE->copyTemplateArgumentsInto(TABuffer); 5674 ExplicitTemplateArgs = &TABuffer; 5675 } 5676 5677 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 5678 Sema::LookupOrdinaryName); 5679 if (SemaRef.DiagnoseEmptyLookup(S, SS, R)) 5680 return Destroy(SemaRef, Fn, Args, NumArgs); 5681 5682 assert(!R.empty() && "lookup results empty despite recovery"); 5683 5684 // Build an implicit member call if appropriate. Just drop the 5685 // casts and such from the call, we don't really care. 5686 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 5687 if ((*R.begin())->isCXXClassMember()) 5688 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 5689 else if (ExplicitTemplateArgs) 5690 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 5691 else 5692 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 5693 5694 if (NewFn.isInvalid()) 5695 return Destroy(SemaRef, Fn, Args, NumArgs); 5696 5697 Fn->Destroy(SemaRef.Context); 5698 5699 // This shouldn't cause an infinite loop because we're giving it 5700 // an expression with non-empty lookup results, which should never 5701 // end up here. 5702 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 5703 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 5704 CommaLocs, RParenLoc); 5705} 5706 5707/// ResolveOverloadedCallFn - Given the call expression that calls Fn 5708/// (which eventually refers to the declaration Func) and the call 5709/// arguments Args/NumArgs, attempt to resolve the function call down 5710/// to a specific function. If overload resolution succeeds, returns 5711/// the function declaration produced by overload 5712/// resolution. Otherwise, emits diagnostics, deletes all of the 5713/// arguments and Fn, and returns NULL. 5714Sema::OwningExprResult 5715Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn, UnresolvedLookupExpr *ULE, 5716 SourceLocation LParenLoc, 5717 Expr **Args, unsigned NumArgs, 5718 SourceLocation *CommaLocs, 5719 SourceLocation RParenLoc) { 5720#ifndef NDEBUG 5721 if (ULE->requiresADL()) { 5722 // To do ADL, we must have found an unqualified name. 5723 assert(!ULE->getQualifier() && "qualified name with ADL"); 5724 5725 // We don't perform ADL for implicit declarations of builtins. 5726 // Verify that this was correctly set up. 5727 FunctionDecl *F; 5728 if (ULE->decls_begin() + 1 == ULE->decls_end() && 5729 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 5730 F->getBuiltinID() && F->isImplicit()) 5731 assert(0 && "performing ADL for builtin"); 5732 5733 // We don't perform ADL in C. 5734 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 5735 } 5736#endif 5737 5738 OverloadCandidateSet CandidateSet(Fn->getExprLoc()); 5739 5740 // Add the functions denoted by the callee to the set of candidate 5741 // functions, including those from argument-dependent lookup. 5742 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 5743 5744 // If we found nothing, try to recover. 5745 // AddRecoveryCallCandidates diagnoses the error itself, so we just 5746 // bailout out if it fails. 5747 if (CandidateSet.empty()) 5748 return BuildRecoveryCallExpr(*this, S, Fn, ULE, LParenLoc, Args, NumArgs, 5749 CommaLocs, RParenLoc); 5750 5751 OverloadCandidateSet::iterator Best; 5752 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 5753 case OR_Success: { 5754 FunctionDecl *FDecl = Best->Function; 5755 CheckUnresolvedLookupAccess(ULE, Best->FoundDecl); 5756 Fn = FixOverloadedFunctionReference(Fn, Best->FoundDecl, FDecl); 5757 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 5758 } 5759 5760 case OR_No_Viable_Function: 5761 Diag(Fn->getSourceRange().getBegin(), 5762 diag::err_ovl_no_viable_function_in_call) 5763 << ULE->getName() << Fn->getSourceRange(); 5764 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5765 break; 5766 5767 case OR_Ambiguous: 5768 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 5769 << ULE->getName() << Fn->getSourceRange(); 5770 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 5771 break; 5772 5773 case OR_Deleted: 5774 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 5775 << Best->Function->isDeleted() 5776 << ULE->getName() 5777 << Fn->getSourceRange(); 5778 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5779 break; 5780 } 5781 5782 // Overload resolution failed. Destroy all of the subexpressions and 5783 // return NULL. 5784 Fn->Destroy(Context); 5785 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5786 Args[Arg]->Destroy(Context); 5787 return ExprError(); 5788} 5789 5790static bool IsOverloaded(const UnresolvedSetImpl &Functions) { 5791 return Functions.size() > 1 || 5792 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 5793} 5794 5795/// \brief Create a unary operation that may resolve to an overloaded 5796/// operator. 5797/// 5798/// \param OpLoc The location of the operator itself (e.g., '*'). 5799/// 5800/// \param OpcIn The UnaryOperator::Opcode that describes this 5801/// operator. 5802/// 5803/// \param Functions The set of non-member functions that will be 5804/// considered by overload resolution. The caller needs to build this 5805/// set based on the context using, e.g., 5806/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5807/// set should not contain any member functions; those will be added 5808/// by CreateOverloadedUnaryOp(). 5809/// 5810/// \param input The input argument. 5811Sema::OwningExprResult 5812Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, unsigned OpcIn, 5813 const UnresolvedSetImpl &Fns, 5814 ExprArg input) { 5815 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 5816 Expr *Input = (Expr *)input.get(); 5817 5818 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 5819 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 5820 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5821 5822 Expr *Args[2] = { Input, 0 }; 5823 unsigned NumArgs = 1; 5824 5825 // For post-increment and post-decrement, add the implicit '0' as 5826 // the second argument, so that we know this is a post-increment or 5827 // post-decrement. 5828 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 5829 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 5830 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 5831 SourceLocation()); 5832 NumArgs = 2; 5833 } 5834 5835 if (Input->isTypeDependent()) { 5836 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 5837 UnresolvedLookupExpr *Fn 5838 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 5839 0, SourceRange(), OpName, OpLoc, 5840 /*ADL*/ true, IsOverloaded(Fns)); 5841 Fn->addDecls(Fns.begin(), Fns.end()); 5842 5843 input.release(); 5844 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 5845 &Args[0], NumArgs, 5846 Context.DependentTy, 5847 OpLoc)); 5848 } 5849 5850 // Build an empty overload set. 5851 OverloadCandidateSet CandidateSet(OpLoc); 5852 5853 // Add the candidates from the given function set. 5854 AddFunctionCandidates(Fns, &Args[0], NumArgs, CandidateSet, false); 5855 5856 // Add operator candidates that are member functions. 5857 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5858 5859 // Add candidates from ADL. 5860 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 5861 Args, NumArgs, 5862 /*ExplicitTemplateArgs*/ 0, 5863 CandidateSet); 5864 5865 // Add builtin operator candidates. 5866 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5867 5868 // Perform overload resolution. 5869 OverloadCandidateSet::iterator Best; 5870 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5871 case OR_Success: { 5872 // We found a built-in operator or an overloaded operator. 5873 FunctionDecl *FnDecl = Best->Function; 5874 5875 if (FnDecl) { 5876 // We matched an overloaded operator. Build a call to that 5877 // operator. 5878 5879 // Convert the arguments. 5880 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 5881 CheckMemberOperatorAccess(OpLoc, Args[0], 0, Best->FoundDecl); 5882 5883 if (PerformObjectArgumentInitialization(Input, /*Qualifier=*/0, 5884 Best->FoundDecl, Method)) 5885 return ExprError(); 5886 } else { 5887 // Convert the arguments. 5888 OwningExprResult InputInit 5889 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 5890 FnDecl->getParamDecl(0)), 5891 SourceLocation(), 5892 move(input)); 5893 if (InputInit.isInvalid()) 5894 return ExprError(); 5895 5896 input = move(InputInit); 5897 Input = (Expr *)input.get(); 5898 } 5899 5900 // Determine the result type 5901 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 5902 5903 // Build the actual expression node. 5904 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5905 SourceLocation()); 5906 UsualUnaryConversions(FnExpr); 5907 5908 input.release(); 5909 Args[0] = Input; 5910 ExprOwningPtr<CallExpr> TheCall(this, 5911 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 5912 Args, NumArgs, ResultTy, OpLoc)); 5913 5914 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 5915 FnDecl)) 5916 return ExprError(); 5917 5918 return MaybeBindToTemporary(TheCall.release()); 5919 } else { 5920 // We matched a built-in operator. Convert the arguments, then 5921 // break out so that we will build the appropriate built-in 5922 // operator node. 5923 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 5924 Best->Conversions[0], AA_Passing)) 5925 return ExprError(); 5926 5927 break; 5928 } 5929 } 5930 5931 case OR_No_Viable_Function: 5932 // No viable function; fall through to handling this as a 5933 // built-in operator, which will produce an error message for us. 5934 break; 5935 5936 case OR_Ambiguous: 5937 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5938 << UnaryOperator::getOpcodeStr(Opc) 5939 << Input->getSourceRange(); 5940 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs, 5941 UnaryOperator::getOpcodeStr(Opc), OpLoc); 5942 return ExprError(); 5943 5944 case OR_Deleted: 5945 Diag(OpLoc, diag::err_ovl_deleted_oper) 5946 << Best->Function->isDeleted() 5947 << UnaryOperator::getOpcodeStr(Opc) 5948 << Input->getSourceRange(); 5949 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 5950 return ExprError(); 5951 } 5952 5953 // Either we found no viable overloaded operator or we matched a 5954 // built-in operator. In either case, fall through to trying to 5955 // build a built-in operation. 5956 input.release(); 5957 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 5958} 5959 5960/// \brief Create a binary operation that may resolve to an overloaded 5961/// operator. 5962/// 5963/// \param OpLoc The location of the operator itself (e.g., '+'). 5964/// 5965/// \param OpcIn The BinaryOperator::Opcode that describes this 5966/// operator. 5967/// 5968/// \param Functions The set of non-member functions that will be 5969/// considered by overload resolution. The caller needs to build this 5970/// set based on the context using, e.g., 5971/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5972/// set should not contain any member functions; those will be added 5973/// by CreateOverloadedBinOp(). 5974/// 5975/// \param LHS Left-hand argument. 5976/// \param RHS Right-hand argument. 5977Sema::OwningExprResult 5978Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 5979 unsigned OpcIn, 5980 const UnresolvedSetImpl &Fns, 5981 Expr *LHS, Expr *RHS) { 5982 Expr *Args[2] = { LHS, RHS }; 5983 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 5984 5985 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 5986 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 5987 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5988 5989 // If either side is type-dependent, create an appropriate dependent 5990 // expression. 5991 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 5992 if (Fns.empty()) { 5993 // If there are no functions to store, just build a dependent 5994 // BinaryOperator or CompoundAssignment. 5995 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 5996 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 5997 Context.DependentTy, OpLoc)); 5998 5999 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 6000 Context.DependentTy, 6001 Context.DependentTy, 6002 Context.DependentTy, 6003 OpLoc)); 6004 } 6005 6006 // FIXME: save results of ADL from here? 6007 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6008 UnresolvedLookupExpr *Fn 6009 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6010 0, SourceRange(), OpName, OpLoc, 6011 /*ADL*/ true, IsOverloaded(Fns)); 6012 6013 Fn->addDecls(Fns.begin(), Fns.end()); 6014 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 6015 Args, 2, 6016 Context.DependentTy, 6017 OpLoc)); 6018 } 6019 6020 // If this is the .* operator, which is not overloadable, just 6021 // create a built-in binary operator. 6022 if (Opc == BinaryOperator::PtrMemD) 6023 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6024 6025 // If this is the assignment operator, we only perform overload resolution 6026 // if the left-hand side is a class or enumeration type. This is actually 6027 // a hack. The standard requires that we do overload resolution between the 6028 // various built-in candidates, but as DR507 points out, this can lead to 6029 // problems. So we do it this way, which pretty much follows what GCC does. 6030 // Note that we go the traditional code path for compound assignment forms. 6031 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 6032 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6033 6034 // Build an empty overload set. 6035 OverloadCandidateSet CandidateSet(OpLoc); 6036 6037 // Add the candidates from the given function set. 6038 AddFunctionCandidates(Fns, Args, 2, CandidateSet, false); 6039 6040 // Add operator candidates that are member functions. 6041 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6042 6043 // Add candidates from ADL. 6044 AddArgumentDependentLookupCandidates(OpName, /*Operator*/ true, 6045 Args, 2, 6046 /*ExplicitTemplateArgs*/ 0, 6047 CandidateSet); 6048 6049 // Add builtin operator candidates. 6050 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 6051 6052 // Perform overload resolution. 6053 OverloadCandidateSet::iterator Best; 6054 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6055 case OR_Success: { 6056 // We found a built-in operator or an overloaded operator. 6057 FunctionDecl *FnDecl = Best->Function; 6058 6059 if (FnDecl) { 6060 // We matched an overloaded operator. Build a call to that 6061 // operator. 6062 6063 // Convert the arguments. 6064 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 6065 // Best->Access is only meaningful for class members. 6066 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl); 6067 6068 OwningExprResult Arg1 6069 = PerformCopyInitialization( 6070 InitializedEntity::InitializeParameter( 6071 FnDecl->getParamDecl(0)), 6072 SourceLocation(), 6073 Owned(Args[1])); 6074 if (Arg1.isInvalid()) 6075 return ExprError(); 6076 6077 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6078 Best->FoundDecl, Method)) 6079 return ExprError(); 6080 6081 Args[1] = RHS = Arg1.takeAs<Expr>(); 6082 } else { 6083 // Convert the arguments. 6084 OwningExprResult Arg0 6085 = PerformCopyInitialization( 6086 InitializedEntity::InitializeParameter( 6087 FnDecl->getParamDecl(0)), 6088 SourceLocation(), 6089 Owned(Args[0])); 6090 if (Arg0.isInvalid()) 6091 return ExprError(); 6092 6093 OwningExprResult Arg1 6094 = PerformCopyInitialization( 6095 InitializedEntity::InitializeParameter( 6096 FnDecl->getParamDecl(1)), 6097 SourceLocation(), 6098 Owned(Args[1])); 6099 if (Arg1.isInvalid()) 6100 return ExprError(); 6101 Args[0] = LHS = Arg0.takeAs<Expr>(); 6102 Args[1] = RHS = Arg1.takeAs<Expr>(); 6103 } 6104 6105 // Determine the result type 6106 QualType ResultTy 6107 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6108 ResultTy = ResultTy.getNonReferenceType(); 6109 6110 // Build the actual expression node. 6111 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6112 OpLoc); 6113 UsualUnaryConversions(FnExpr); 6114 6115 ExprOwningPtr<CXXOperatorCallExpr> 6116 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 6117 Args, 2, ResultTy, 6118 OpLoc)); 6119 6120 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 6121 FnDecl)) 6122 return ExprError(); 6123 6124 return MaybeBindToTemporary(TheCall.release()); 6125 } else { 6126 // We matched a built-in operator. Convert the arguments, then 6127 // break out so that we will build the appropriate built-in 6128 // operator node. 6129 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6130 Best->Conversions[0], AA_Passing) || 6131 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6132 Best->Conversions[1], AA_Passing)) 6133 return ExprError(); 6134 6135 break; 6136 } 6137 } 6138 6139 case OR_No_Viable_Function: { 6140 // C++ [over.match.oper]p9: 6141 // If the operator is the operator , [...] and there are no 6142 // viable functions, then the operator is assumed to be the 6143 // built-in operator and interpreted according to clause 5. 6144 if (Opc == BinaryOperator::Comma) 6145 break; 6146 6147 // For class as left operand for assignment or compound assigment operator 6148 // do not fall through to handling in built-in, but report that no overloaded 6149 // assignment operator found 6150 OwningExprResult Result = ExprError(); 6151 if (Args[0]->getType()->isRecordType() && 6152 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 6153 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6154 << BinaryOperator::getOpcodeStr(Opc) 6155 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6156 } else { 6157 // No viable function; try to create a built-in operation, which will 6158 // produce an error. Then, show the non-viable candidates. 6159 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6160 } 6161 assert(Result.isInvalid() && 6162 "C++ binary operator overloading is missing candidates!"); 6163 if (Result.isInvalid()) 6164 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6165 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6166 return move(Result); 6167 } 6168 6169 case OR_Ambiguous: 6170 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6171 << BinaryOperator::getOpcodeStr(Opc) 6172 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6173 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6174 BinaryOperator::getOpcodeStr(Opc), OpLoc); 6175 return ExprError(); 6176 6177 case OR_Deleted: 6178 Diag(OpLoc, diag::err_ovl_deleted_oper) 6179 << Best->Function->isDeleted() 6180 << BinaryOperator::getOpcodeStr(Opc) 6181 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6182 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2); 6183 return ExprError(); 6184 } 6185 6186 // We matched a built-in operator; build it. 6187 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 6188} 6189 6190Action::OwningExprResult 6191Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 6192 SourceLocation RLoc, 6193 ExprArg Base, ExprArg Idx) { 6194 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 6195 static_cast<Expr*>(Idx.get()) }; 6196 DeclarationName OpName = 6197 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 6198 6199 // If either side is type-dependent, create an appropriate dependent 6200 // expression. 6201 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 6202 6203 CXXRecordDecl *NamingClass = 0; // because lookup ignores member operators 6204 UnresolvedLookupExpr *Fn 6205 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, NamingClass, 6206 0, SourceRange(), OpName, LLoc, 6207 /*ADL*/ true, /*Overloaded*/ false); 6208 // Can't add any actual overloads yet 6209 6210 Base.release(); 6211 Idx.release(); 6212 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 6213 Args, 2, 6214 Context.DependentTy, 6215 RLoc)); 6216 } 6217 6218 // Build an empty overload set. 6219 OverloadCandidateSet CandidateSet(LLoc); 6220 6221 // Subscript can only be overloaded as a member function. 6222 6223 // Add operator candidates that are member functions. 6224 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6225 6226 // Add builtin operator candidates. 6227 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 6228 6229 // Perform overload resolution. 6230 OverloadCandidateSet::iterator Best; 6231 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 6232 case OR_Success: { 6233 // We found a built-in operator or an overloaded operator. 6234 FunctionDecl *FnDecl = Best->Function; 6235 6236 if (FnDecl) { 6237 // We matched an overloaded operator. Build a call to that 6238 // operator. 6239 6240 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl); 6241 6242 // Convert the arguments. 6243 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 6244 if (PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/0, 6245 Best->FoundDecl, Method)) 6246 return ExprError(); 6247 6248 // Convert the arguments. 6249 OwningExprResult InputInit 6250 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6251 FnDecl->getParamDecl(0)), 6252 SourceLocation(), 6253 Owned(Args[1])); 6254 if (InputInit.isInvalid()) 6255 return ExprError(); 6256 6257 Args[1] = InputInit.takeAs<Expr>(); 6258 6259 // Determine the result type 6260 QualType ResultTy 6261 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 6262 ResultTy = ResultTy.getNonReferenceType(); 6263 6264 // Build the actual expression node. 6265 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 6266 LLoc); 6267 UsualUnaryConversions(FnExpr); 6268 6269 Base.release(); 6270 Idx.release(); 6271 ExprOwningPtr<CXXOperatorCallExpr> 6272 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 6273 FnExpr, Args, 2, 6274 ResultTy, RLoc)); 6275 6276 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 6277 FnDecl)) 6278 return ExprError(); 6279 6280 return MaybeBindToTemporary(TheCall.release()); 6281 } else { 6282 // We matched a built-in operator. Convert the arguments, then 6283 // break out so that we will build the appropriate built-in 6284 // operator node. 6285 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 6286 Best->Conversions[0], AA_Passing) || 6287 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 6288 Best->Conversions[1], AA_Passing)) 6289 return ExprError(); 6290 6291 break; 6292 } 6293 } 6294 6295 case OR_No_Viable_Function: { 6296 if (CandidateSet.empty()) 6297 Diag(LLoc, diag::err_ovl_no_oper) 6298 << Args[0]->getType() << /*subscript*/ 0 6299 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6300 else 6301 Diag(LLoc, diag::err_ovl_no_viable_subscript) 6302 << Args[0]->getType() 6303 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6304 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6305 "[]", LLoc); 6306 return ExprError(); 6307 } 6308 6309 case OR_Ambiguous: 6310 Diag(LLoc, diag::err_ovl_ambiguous_oper) 6311 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6312 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, 2, 6313 "[]", LLoc); 6314 return ExprError(); 6315 6316 case OR_Deleted: 6317 Diag(LLoc, diag::err_ovl_deleted_oper) 6318 << Best->Function->isDeleted() << "[]" 6319 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 6320 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, 2, 6321 "[]", LLoc); 6322 return ExprError(); 6323 } 6324 6325 // We matched a built-in operator; build it. 6326 Base.release(); 6327 Idx.release(); 6328 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 6329 Owned(Args[1]), RLoc); 6330} 6331 6332/// BuildCallToMemberFunction - Build a call to a member 6333/// function. MemExpr is the expression that refers to the member 6334/// function (and includes the object parameter), Args/NumArgs are the 6335/// arguments to the function call (not including the object 6336/// parameter). The caller needs to validate that the member 6337/// expression refers to a member function or an overloaded member 6338/// function. 6339Sema::OwningExprResult 6340Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 6341 SourceLocation LParenLoc, Expr **Args, 6342 unsigned NumArgs, SourceLocation *CommaLocs, 6343 SourceLocation RParenLoc) { 6344 // Dig out the member expression. This holds both the object 6345 // argument and the member function we're referring to. 6346 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 6347 6348 MemberExpr *MemExpr; 6349 CXXMethodDecl *Method = 0; 6350 DeclAccessPair FoundDecl = DeclAccessPair::make(0, AS_public); 6351 NestedNameSpecifier *Qualifier = 0; 6352 if (isa<MemberExpr>(NakedMemExpr)) { 6353 MemExpr = cast<MemberExpr>(NakedMemExpr); 6354 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 6355 FoundDecl = MemExpr->getFoundDecl(); 6356 Qualifier = MemExpr->getQualifier(); 6357 } else { 6358 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 6359 Qualifier = UnresExpr->getQualifier(); 6360 6361 QualType ObjectType = UnresExpr->getBaseType(); 6362 6363 // Add overload candidates 6364 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc()); 6365 6366 // FIXME: avoid copy. 6367 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6368 if (UnresExpr->hasExplicitTemplateArgs()) { 6369 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6370 TemplateArgs = &TemplateArgsBuffer; 6371 } 6372 6373 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 6374 E = UnresExpr->decls_end(); I != E; ++I) { 6375 6376 NamedDecl *Func = *I; 6377 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 6378 if (isa<UsingShadowDecl>(Func)) 6379 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 6380 6381 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 6382 // If explicit template arguments were provided, we can't call a 6383 // non-template member function. 6384 if (TemplateArgs) 6385 continue; 6386 6387 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType, 6388 Args, NumArgs, 6389 CandidateSet, /*SuppressUserConversions=*/false); 6390 } else { 6391 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 6392 I.getPair(), ActingDC, TemplateArgs, 6393 ObjectType, Args, NumArgs, 6394 CandidateSet, 6395 /*SuppressUsedConversions=*/false); 6396 } 6397 } 6398 6399 DeclarationName DeclName = UnresExpr->getMemberName(); 6400 6401 OverloadCandidateSet::iterator Best; 6402 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 6403 case OR_Success: 6404 Method = cast<CXXMethodDecl>(Best->Function); 6405 FoundDecl = Best->FoundDecl; 6406 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl); 6407 break; 6408 6409 case OR_No_Viable_Function: 6410 Diag(UnresExpr->getMemberLoc(), 6411 diag::err_ovl_no_viable_member_function_in_call) 6412 << DeclName << MemExprE->getSourceRange(); 6413 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6414 // FIXME: Leaking incoming expressions! 6415 return ExprError(); 6416 6417 case OR_Ambiguous: 6418 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 6419 << DeclName << MemExprE->getSourceRange(); 6420 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6421 // FIXME: Leaking incoming expressions! 6422 return ExprError(); 6423 6424 case OR_Deleted: 6425 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 6426 << Best->Function->isDeleted() 6427 << DeclName << MemExprE->getSourceRange(); 6428 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6429 // FIXME: Leaking incoming expressions! 6430 return ExprError(); 6431 } 6432 6433 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method); 6434 6435 // If overload resolution picked a static member, build a 6436 // non-member call based on that function. 6437 if (Method->isStatic()) { 6438 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 6439 Args, NumArgs, RParenLoc); 6440 } 6441 6442 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 6443 } 6444 6445 assert(Method && "Member call to something that isn't a method?"); 6446 ExprOwningPtr<CXXMemberCallExpr> 6447 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 6448 NumArgs, 6449 Method->getResultType().getNonReferenceType(), 6450 RParenLoc)); 6451 6452 // Check for a valid return type. 6453 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 6454 TheCall.get(), Method)) 6455 return ExprError(); 6456 6457 // Convert the object argument (for a non-static member function call). 6458 // We only need to do this if there was actually an overload; otherwise 6459 // it was done at lookup. 6460 Expr *ObjectArg = MemExpr->getBase(); 6461 if (!Method->isStatic() && 6462 PerformObjectArgumentInitialization(ObjectArg, Qualifier, 6463 FoundDecl, Method)) 6464 return ExprError(); 6465 MemExpr->setBase(ObjectArg); 6466 6467 // Convert the rest of the arguments 6468 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 6469 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 6470 RParenLoc)) 6471 return ExprError(); 6472 6473 if (CheckFunctionCall(Method, TheCall.get())) 6474 return ExprError(); 6475 6476 return MaybeBindToTemporary(TheCall.release()); 6477} 6478 6479/// BuildCallToObjectOfClassType - Build a call to an object of class 6480/// type (C++ [over.call.object]), which can end up invoking an 6481/// overloaded function call operator (@c operator()) or performing a 6482/// user-defined conversion on the object argument. 6483Sema::ExprResult 6484Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 6485 SourceLocation LParenLoc, 6486 Expr **Args, unsigned NumArgs, 6487 SourceLocation *CommaLocs, 6488 SourceLocation RParenLoc) { 6489 assert(Object->getType()->isRecordType() && "Requires object type argument"); 6490 const RecordType *Record = Object->getType()->getAs<RecordType>(); 6491 6492 // C++ [over.call.object]p1: 6493 // If the primary-expression E in the function call syntax 6494 // evaluates to a class object of type "cv T", then the set of 6495 // candidate functions includes at least the function call 6496 // operators of T. The function call operators of T are obtained by 6497 // ordinary lookup of the name operator() in the context of 6498 // (E).operator(). 6499 OverloadCandidateSet CandidateSet(LParenLoc); 6500 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 6501 6502 if (RequireCompleteType(LParenLoc, Object->getType(), 6503 PDiag(diag::err_incomplete_object_call) 6504 << Object->getSourceRange())) 6505 return true; 6506 6507 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 6508 LookupQualifiedName(R, Record->getDecl()); 6509 R.suppressDiagnostics(); 6510 6511 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6512 Oper != OperEnd; ++Oper) { 6513 AddMethodCandidate(Oper.getPair(), Object->getType(), 6514 Args, NumArgs, CandidateSet, 6515 /*SuppressUserConversions=*/ false); 6516 } 6517 6518 // C++ [over.call.object]p2: 6519 // In addition, for each conversion function declared in T of the 6520 // form 6521 // 6522 // operator conversion-type-id () cv-qualifier; 6523 // 6524 // where cv-qualifier is the same cv-qualification as, or a 6525 // greater cv-qualification than, cv, and where conversion-type-id 6526 // denotes the type "pointer to function of (P1,...,Pn) returning 6527 // R", or the type "reference to pointer to function of 6528 // (P1,...,Pn) returning R", or the type "reference to function 6529 // of (P1,...,Pn) returning R", a surrogate call function [...] 6530 // is also considered as a candidate function. Similarly, 6531 // surrogate call functions are added to the set of candidate 6532 // functions for each conversion function declared in an 6533 // accessible base class provided the function is not hidden 6534 // within T by another intervening declaration. 6535 const UnresolvedSetImpl *Conversions 6536 = cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions(); 6537 for (UnresolvedSetImpl::iterator I = Conversions->begin(), 6538 E = Conversions->end(); I != E; ++I) { 6539 NamedDecl *D = *I; 6540 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 6541 if (isa<UsingShadowDecl>(D)) 6542 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 6543 6544 // Skip over templated conversion functions; they aren't 6545 // surrogates. 6546 if (isa<FunctionTemplateDecl>(D)) 6547 continue; 6548 6549 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 6550 6551 // Strip the reference type (if any) and then the pointer type (if 6552 // any) to get down to what might be a function type. 6553 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 6554 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 6555 ConvType = ConvPtrType->getPointeeType(); 6556 6557 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 6558 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto, 6559 Object->getType(), Args, NumArgs, 6560 CandidateSet); 6561 } 6562 6563 // Perform overload resolution. 6564 OverloadCandidateSet::iterator Best; 6565 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 6566 case OR_Success: 6567 // Overload resolution succeeded; we'll build the appropriate call 6568 // below. 6569 break; 6570 6571 case OR_No_Viable_Function: 6572 if (CandidateSet.empty()) 6573 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 6574 << Object->getType() << /*call*/ 1 6575 << Object->getSourceRange(); 6576 else 6577 Diag(Object->getSourceRange().getBegin(), 6578 diag::err_ovl_no_viable_object_call) 6579 << Object->getType() << Object->getSourceRange(); 6580 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6581 break; 6582 6583 case OR_Ambiguous: 6584 Diag(Object->getSourceRange().getBegin(), 6585 diag::err_ovl_ambiguous_object_call) 6586 << Object->getType() << Object->getSourceRange(); 6587 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, Args, NumArgs); 6588 break; 6589 6590 case OR_Deleted: 6591 Diag(Object->getSourceRange().getBegin(), 6592 diag::err_ovl_deleted_object_call) 6593 << Best->Function->isDeleted() 6594 << Object->getType() << Object->getSourceRange(); 6595 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, Args, NumArgs); 6596 break; 6597 } 6598 6599 if (Best == CandidateSet.end()) { 6600 // We had an error; delete all of the subexpressions and return 6601 // the error. 6602 Object->Destroy(Context); 6603 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6604 Args[ArgIdx]->Destroy(Context); 6605 return true; 6606 } 6607 6608 if (Best->Function == 0) { 6609 // Since there is no function declaration, this is one of the 6610 // surrogate candidates. Dig out the conversion function. 6611 CXXConversionDecl *Conv 6612 = cast<CXXConversionDecl>( 6613 Best->Conversions[0].UserDefined.ConversionFunction); 6614 6615 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6616 6617 // We selected one of the surrogate functions that converts the 6618 // object parameter to a function pointer. Perform the conversion 6619 // on the object argument, then let ActOnCallExpr finish the job. 6620 6621 // Create an implicit member expr to refer to the conversion operator. 6622 // and then call it. 6623 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Best->FoundDecl, 6624 Conv); 6625 6626 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 6627 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 6628 CommaLocs, RParenLoc).result(); 6629 } 6630 6631 CheckMemberOperatorAccess(LParenLoc, Object, 0, Best->FoundDecl); 6632 6633 // We found an overloaded operator(). Build a CXXOperatorCallExpr 6634 // that calls this method, using Object for the implicit object 6635 // parameter and passing along the remaining arguments. 6636 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6637 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 6638 6639 unsigned NumArgsInProto = Proto->getNumArgs(); 6640 unsigned NumArgsToCheck = NumArgs; 6641 6642 // Build the full argument list for the method call (the 6643 // implicit object parameter is placed at the beginning of the 6644 // list). 6645 Expr **MethodArgs; 6646 if (NumArgs < NumArgsInProto) { 6647 NumArgsToCheck = NumArgsInProto; 6648 MethodArgs = new Expr*[NumArgsInProto + 1]; 6649 } else { 6650 MethodArgs = new Expr*[NumArgs + 1]; 6651 } 6652 MethodArgs[0] = Object; 6653 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 6654 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 6655 6656 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 6657 SourceLocation()); 6658 UsualUnaryConversions(NewFn); 6659 6660 // Once we've built TheCall, all of the expressions are properly 6661 // owned. 6662 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6663 ExprOwningPtr<CXXOperatorCallExpr> 6664 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 6665 MethodArgs, NumArgs + 1, 6666 ResultTy, RParenLoc)); 6667 delete [] MethodArgs; 6668 6669 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 6670 Method)) 6671 return true; 6672 6673 // We may have default arguments. If so, we need to allocate more 6674 // slots in the call for them. 6675 if (NumArgs < NumArgsInProto) 6676 TheCall->setNumArgs(Context, NumArgsInProto + 1); 6677 else if (NumArgs > NumArgsInProto) 6678 NumArgsToCheck = NumArgsInProto; 6679 6680 bool IsError = false; 6681 6682 // Initialize the implicit object parameter. 6683 IsError |= PerformObjectArgumentInitialization(Object, /*Qualifier=*/0, 6684 Best->FoundDecl, Method); 6685 TheCall->setArg(0, Object); 6686 6687 6688 // Check the argument types. 6689 for (unsigned i = 0; i != NumArgsToCheck; i++) { 6690 Expr *Arg; 6691 if (i < NumArgs) { 6692 Arg = Args[i]; 6693 6694 // Pass the argument. 6695 6696 OwningExprResult InputInit 6697 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 6698 Method->getParamDecl(i)), 6699 SourceLocation(), Owned(Arg)); 6700 6701 IsError |= InputInit.isInvalid(); 6702 Arg = InputInit.takeAs<Expr>(); 6703 } else { 6704 OwningExprResult DefArg 6705 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 6706 if (DefArg.isInvalid()) { 6707 IsError = true; 6708 break; 6709 } 6710 6711 Arg = DefArg.takeAs<Expr>(); 6712 } 6713 6714 TheCall->setArg(i + 1, Arg); 6715 } 6716 6717 // If this is a variadic call, handle args passed through "...". 6718 if (Proto->isVariadic()) { 6719 // Promote the arguments (C99 6.5.2.2p7). 6720 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 6721 Expr *Arg = Args[i]; 6722 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 6723 TheCall->setArg(i + 1, Arg); 6724 } 6725 } 6726 6727 if (IsError) return true; 6728 6729 if (CheckFunctionCall(Method, TheCall.get())) 6730 return true; 6731 6732 return MaybeBindToTemporary(TheCall.release()).result(); 6733} 6734 6735/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 6736/// (if one exists), where @c Base is an expression of class type and 6737/// @c Member is the name of the member we're trying to find. 6738Sema::OwningExprResult 6739Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 6740 Expr *Base = static_cast<Expr *>(BaseIn.get()); 6741 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 6742 6743 SourceLocation Loc = Base->getExprLoc(); 6744 6745 // C++ [over.ref]p1: 6746 // 6747 // [...] An expression x->m is interpreted as (x.operator->())->m 6748 // for a class object x of type T if T::operator->() exists and if 6749 // the operator is selected as the best match function by the 6750 // overload resolution mechanism (13.3). 6751 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 6752 OverloadCandidateSet CandidateSet(Loc); 6753 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 6754 6755 if (RequireCompleteType(Loc, Base->getType(), 6756 PDiag(diag::err_typecheck_incomplete_tag) 6757 << Base->getSourceRange())) 6758 return ExprError(); 6759 6760 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 6761 LookupQualifiedName(R, BaseRecord->getDecl()); 6762 R.suppressDiagnostics(); 6763 6764 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 6765 Oper != OperEnd; ++Oper) { 6766 AddMethodCandidate(Oper.getPair(), Base->getType(), 0, 0, CandidateSet, 6767 /*SuppressUserConversions=*/false); 6768 } 6769 6770 // Perform overload resolution. 6771 OverloadCandidateSet::iterator Best; 6772 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 6773 case OR_Success: 6774 // Overload resolution succeeded; we'll build the call below. 6775 break; 6776 6777 case OR_No_Viable_Function: 6778 if (CandidateSet.empty()) 6779 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 6780 << Base->getType() << Base->getSourceRange(); 6781 else 6782 Diag(OpLoc, diag::err_ovl_no_viable_oper) 6783 << "operator->" << Base->getSourceRange(); 6784 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6785 return ExprError(); 6786 6787 case OR_Ambiguous: 6788 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 6789 << "->" << Base->getSourceRange(); 6790 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, &Base, 1); 6791 return ExprError(); 6792 6793 case OR_Deleted: 6794 Diag(OpLoc, diag::err_ovl_deleted_oper) 6795 << Best->Function->isDeleted() 6796 << "->" << Base->getSourceRange(); 6797 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, &Base, 1); 6798 return ExprError(); 6799 } 6800 6801 CheckMemberOperatorAccess(OpLoc, Base, 0, Best->FoundDecl); 6802 6803 // Convert the object parameter. 6804 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6805 if (PerformObjectArgumentInitialization(Base, /*Qualifier=*/0, 6806 Best->FoundDecl, Method)) 6807 return ExprError(); 6808 6809 // No concerns about early exits now. 6810 BaseIn.release(); 6811 6812 // Build the operator call. 6813 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 6814 SourceLocation()); 6815 UsualUnaryConversions(FnExpr); 6816 6817 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6818 ExprOwningPtr<CXXOperatorCallExpr> 6819 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 6820 &Base, 1, ResultTy, OpLoc)); 6821 6822 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 6823 Method)) 6824 return ExprError(); 6825 return move(TheCall); 6826} 6827 6828/// FixOverloadedFunctionReference - E is an expression that refers to 6829/// a C++ overloaded function (possibly with some parentheses and 6830/// perhaps a '&' around it). We have resolved the overloaded function 6831/// to the function declaration Fn, so patch up the expression E to 6832/// refer (possibly indirectly) to Fn. Returns the new expr. 6833Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found, 6834 FunctionDecl *Fn) { 6835 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 6836 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), 6837 Found, Fn); 6838 if (SubExpr == PE->getSubExpr()) 6839 return PE->Retain(); 6840 6841 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 6842 } 6843 6844 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6845 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), 6846 Found, Fn); 6847 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 6848 SubExpr->getType()) && 6849 "Implicit cast type cannot be determined from overload"); 6850 if (SubExpr == ICE->getSubExpr()) 6851 return ICE->Retain(); 6852 6853 return new (Context) ImplicitCastExpr(ICE->getType(), 6854 ICE->getCastKind(), 6855 SubExpr, 6856 ICE->isLvalueCast()); 6857 } 6858 6859 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 6860 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 6861 "Can only take the address of an overloaded function"); 6862 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 6863 if (Method->isStatic()) { 6864 // Do nothing: static member functions aren't any different 6865 // from non-member functions. 6866 } else { 6867 // Fix the sub expression, which really has to be an 6868 // UnresolvedLookupExpr holding an overloaded member function 6869 // or template. 6870 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6871 Found, Fn); 6872 if (SubExpr == UnOp->getSubExpr()) 6873 return UnOp->Retain(); 6874 6875 assert(isa<DeclRefExpr>(SubExpr) 6876 && "fixed to something other than a decl ref"); 6877 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 6878 && "fixed to a member ref with no nested name qualifier"); 6879 6880 // We have taken the address of a pointer to member 6881 // function. Perform the computation here so that we get the 6882 // appropriate pointer to member type. 6883 QualType ClassType 6884 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 6885 QualType MemPtrType 6886 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 6887 6888 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6889 MemPtrType, UnOp->getOperatorLoc()); 6890 } 6891 } 6892 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), 6893 Found, Fn); 6894 if (SubExpr == UnOp->getSubExpr()) 6895 return UnOp->Retain(); 6896 6897 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6898 Context.getPointerType(SubExpr->getType()), 6899 UnOp->getOperatorLoc()); 6900 } 6901 6902 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 6903 // FIXME: avoid copy. 6904 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6905 if (ULE->hasExplicitTemplateArgs()) { 6906 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 6907 TemplateArgs = &TemplateArgsBuffer; 6908 } 6909 6910 return DeclRefExpr::Create(Context, 6911 ULE->getQualifier(), 6912 ULE->getQualifierRange(), 6913 Fn, 6914 ULE->getNameLoc(), 6915 Fn->getType(), 6916 TemplateArgs); 6917 } 6918 6919 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 6920 // FIXME: avoid copy. 6921 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6922 if (MemExpr->hasExplicitTemplateArgs()) { 6923 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6924 TemplateArgs = &TemplateArgsBuffer; 6925 } 6926 6927 Expr *Base; 6928 6929 // If we're filling in 6930 if (MemExpr->isImplicitAccess()) { 6931 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 6932 return DeclRefExpr::Create(Context, 6933 MemExpr->getQualifier(), 6934 MemExpr->getQualifierRange(), 6935 Fn, 6936 MemExpr->getMemberLoc(), 6937 Fn->getType(), 6938 TemplateArgs); 6939 } else { 6940 SourceLocation Loc = MemExpr->getMemberLoc(); 6941 if (MemExpr->getQualifier()) 6942 Loc = MemExpr->getQualifierRange().getBegin(); 6943 Base = new (Context) CXXThisExpr(Loc, 6944 MemExpr->getBaseType(), 6945 /*isImplicit=*/true); 6946 } 6947 } else 6948 Base = MemExpr->getBase()->Retain(); 6949 6950 return MemberExpr::Create(Context, Base, 6951 MemExpr->isArrow(), 6952 MemExpr->getQualifier(), 6953 MemExpr->getQualifierRange(), 6954 Fn, 6955 Found, 6956 MemExpr->getMemberLoc(), 6957 TemplateArgs, 6958 Fn->getType()); 6959 } 6960 6961 assert(false && "Invalid reference to overloaded function"); 6962 return E->Retain(); 6963} 6964 6965Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 6966 DeclAccessPair Found, 6967 FunctionDecl *Fn) { 6968 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Found, Fn)); 6969} 6970 6971} // end namespace clang 6972