SemaOverload.cpp revision 48026d26fb58e413544874eead5491b1452e2ebf
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#include <cstdio> 29 30namespace clang { 31 32/// GetConversionCategory - Retrieve the implicit conversion 33/// category corresponding to the given implicit conversion kind. 34ImplicitConversionCategory 35GetConversionCategory(ImplicitConversionKind Kind) { 36 static const ImplicitConversionCategory 37 Category[(int)ICK_Num_Conversion_Kinds] = { 38 ICC_Identity, 39 ICC_Lvalue_Transformation, 40 ICC_Lvalue_Transformation, 41 ICC_Lvalue_Transformation, 42 ICC_Identity, 43 ICC_Qualification_Adjustment, 44 ICC_Promotion, 45 ICC_Promotion, 46 ICC_Promotion, 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 ICC_Conversion 57 }; 58 return Category[(int)Kind]; 59} 60 61/// GetConversionRank - Retrieve the implicit conversion rank 62/// corresponding to the given implicit conversion kind. 63ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) { 64 static const ImplicitConversionRank 65 Rank[(int)ICK_Num_Conversion_Kinds] = { 66 ICR_Exact_Match, 67 ICR_Exact_Match, 68 ICR_Exact_Match, 69 ICR_Exact_Match, 70 ICR_Exact_Match, 71 ICR_Exact_Match, 72 ICR_Promotion, 73 ICR_Promotion, 74 ICR_Promotion, 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_Conversion, 84 ICR_Conversion 85 }; 86 return Rank[(int)Kind]; 87} 88 89/// GetImplicitConversionName - Return the name of this kind of 90/// implicit conversion. 91const char* GetImplicitConversionName(ImplicitConversionKind Kind) { 92 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = { 93 "No conversion", 94 "Lvalue-to-rvalue", 95 "Array-to-pointer", 96 "Function-to-pointer", 97 "Noreturn adjustment", 98 "Qualification", 99 "Integral promotion", 100 "Floating point promotion", 101 "Complex promotion", 102 "Integral conversion", 103 "Floating conversion", 104 "Complex conversion", 105 "Floating-integral conversion", 106 "Complex-real conversion", 107 "Pointer conversion", 108 "Pointer-to-member conversion", 109 "Boolean conversion", 110 "Compatible-types conversion", 111 "Derived-to-base conversion" 112 }; 113 return Name[Kind]; 114} 115 116/// StandardConversionSequence - Set the standard conversion 117/// sequence to the identity conversion. 118void StandardConversionSequence::setAsIdentityConversion() { 119 First = ICK_Identity; 120 Second = ICK_Identity; 121 Third = ICK_Identity; 122 Deprecated = false; 123 ReferenceBinding = false; 124 DirectBinding = false; 125 RRefBinding = false; 126 CopyConstructor = 0; 127} 128 129/// getRank - Retrieve the rank of this standard conversion sequence 130/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 131/// implicit conversions. 132ImplicitConversionRank StandardConversionSequence::getRank() const { 133 ImplicitConversionRank Rank = ICR_Exact_Match; 134 if (GetConversionRank(First) > Rank) 135 Rank = GetConversionRank(First); 136 if (GetConversionRank(Second) > Rank) 137 Rank = GetConversionRank(Second); 138 if (GetConversionRank(Third) > Rank) 139 Rank = GetConversionRank(Third); 140 return Rank; 141} 142 143/// isPointerConversionToBool - Determines whether this conversion is 144/// a conversion of a pointer or pointer-to-member to bool. This is 145/// used as part of the ranking of standard conversion sequences 146/// (C++ 13.3.3.2p4). 147bool StandardConversionSequence::isPointerConversionToBool() const { 148 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 149 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 150 151 // Note that FromType has not necessarily been transformed by the 152 // array-to-pointer or function-to-pointer implicit conversions, so 153 // check for their presence as well as checking whether FromType is 154 // a pointer. 155 if (ToType->isBooleanType() && 156 (FromType->isPointerType() || FromType->isBlockPointerType() || 157 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 158 return true; 159 160 return false; 161} 162 163/// isPointerConversionToVoidPointer - Determines whether this 164/// conversion is a conversion of a pointer to a void pointer. This is 165/// used as part of the ranking of standard conversion sequences (C++ 166/// 13.3.3.2p4). 167bool 168StandardConversionSequence:: 169isPointerConversionToVoidPointer(ASTContext& Context) const { 170 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 171 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 172 173 // Note that FromType has not necessarily been transformed by the 174 // array-to-pointer implicit conversion, so check for its presence 175 // and redo the conversion to get a pointer. 176 if (First == ICK_Array_To_Pointer) 177 FromType = Context.getArrayDecayedType(FromType); 178 179 if (Second == ICK_Pointer_Conversion && FromType->isPointerType()) 180 if (const PointerType* ToPtrType = ToType->getAs<PointerType>()) 181 return ToPtrType->getPointeeType()->isVoidType(); 182 183 return false; 184} 185 186/// DebugPrint - Print this standard conversion sequence to standard 187/// error. Useful for debugging overloading issues. 188void StandardConversionSequence::DebugPrint() const { 189 bool PrintedSomething = false; 190 if (First != ICK_Identity) { 191 fprintf(stderr, "%s", GetImplicitConversionName(First)); 192 PrintedSomething = true; 193 } 194 195 if (Second != ICK_Identity) { 196 if (PrintedSomething) { 197 fprintf(stderr, " -> "); 198 } 199 fprintf(stderr, "%s", GetImplicitConversionName(Second)); 200 201 if (CopyConstructor) { 202 fprintf(stderr, " (by copy constructor)"); 203 } else if (DirectBinding) { 204 fprintf(stderr, " (direct reference binding)"); 205 } else if (ReferenceBinding) { 206 fprintf(stderr, " (reference binding)"); 207 } 208 PrintedSomething = true; 209 } 210 211 if (Third != ICK_Identity) { 212 if (PrintedSomething) { 213 fprintf(stderr, " -> "); 214 } 215 fprintf(stderr, "%s", GetImplicitConversionName(Third)); 216 PrintedSomething = true; 217 } 218 219 if (!PrintedSomething) { 220 fprintf(stderr, "No conversions required"); 221 } 222} 223 224/// DebugPrint - Print this user-defined conversion sequence to standard 225/// error. Useful for debugging overloading issues. 226void UserDefinedConversionSequence::DebugPrint() const { 227 if (Before.First || Before.Second || Before.Third) { 228 Before.DebugPrint(); 229 fprintf(stderr, " -> "); 230 } 231 fprintf(stderr, "'%s'", ConversionFunction->getNameAsString().c_str()); 232 if (After.First || After.Second || After.Third) { 233 fprintf(stderr, " -> "); 234 After.DebugPrint(); 235 } 236} 237 238/// DebugPrint - Print this implicit conversion sequence to standard 239/// error. Useful for debugging overloading issues. 240void ImplicitConversionSequence::DebugPrint() const { 241 switch (ConversionKind) { 242 case StandardConversion: 243 fprintf(stderr, "Standard conversion: "); 244 Standard.DebugPrint(); 245 break; 246 case UserDefinedConversion: 247 fprintf(stderr, "User-defined conversion: "); 248 UserDefined.DebugPrint(); 249 break; 250 case EllipsisConversion: 251 fprintf(stderr, "Ellipsis conversion"); 252 break; 253 case BadConversion: 254 fprintf(stderr, "Bad conversion"); 255 break; 256 } 257 258 fprintf(stderr, "\n"); 259} 260 261// IsOverload - Determine whether the given New declaration is an 262// overload of the declarations in Old. This routine returns false if 263// New and Old cannot be overloaded, e.g., if New has the same 264// signature as some function in Old (C++ 1.3.10) or if the Old 265// declarations aren't functions (or function templates) at all. When 266// it does return false, MatchedDecl will point to the decl that New 267// cannot be overloaded with. This decl may be a UsingShadowDecl on 268// top of the underlying declaration. 269// 270// Example: Given the following input: 271// 272// void f(int, float); // #1 273// void f(int, int); // #2 274// int f(int, int); // #3 275// 276// When we process #1, there is no previous declaration of "f", 277// so IsOverload will not be used. 278// 279// When we process #2, Old contains only the FunctionDecl for #1. By 280// comparing the parameter types, we see that #1 and #2 are overloaded 281// (since they have different signatures), so this routine returns 282// false; MatchedDecl is unchanged. 283// 284// When we process #3, Old is an overload set containing #1 and #2. We 285// compare the signatures of #3 to #1 (they're overloaded, so we do 286// nothing) and then #3 to #2. Since the signatures of #3 and #2 are 287// identical (return types of functions are not part of the 288// signature), IsOverload returns false and MatchedDecl will be set to 289// point to the FunctionDecl for #2. 290Sema::OverloadKind 291Sema::CheckOverload(FunctionDecl *New, const LookupResult &Old, 292 NamedDecl *&Match) { 293 for (LookupResult::iterator I = Old.begin(), E = Old.end(); 294 I != E; ++I) { 295 NamedDecl *OldD = (*I)->getUnderlyingDecl(); 296 if (FunctionTemplateDecl *OldT = dyn_cast<FunctionTemplateDecl>(OldD)) { 297 if (!IsOverload(New, OldT->getTemplatedDecl())) { 298 Match = *I; 299 return Ovl_Match; 300 } 301 } else if (FunctionDecl *OldF = dyn_cast<FunctionDecl>(OldD)) { 302 if (!IsOverload(New, OldF)) { 303 Match = *I; 304 return Ovl_Match; 305 } 306 } else if (isa<UsingDecl>(OldD) || isa<TagDecl>(OldD)) { 307 // We can overload with these, which can show up when doing 308 // redeclaration checks for UsingDecls. 309 assert(Old.getLookupKind() == LookupUsingDeclName); 310 } else if (isa<UnresolvedUsingValueDecl>(OldD)) { 311 // Optimistically assume that an unresolved using decl will 312 // overload; if it doesn't, we'll have to diagnose during 313 // template instantiation. 314 } else { 315 // (C++ 13p1): 316 // Only function declarations can be overloaded; object and type 317 // declarations cannot be overloaded. 318 Match = *I; 319 return Ovl_NonFunction; 320 } 321 } 322 323 return Ovl_Overload; 324} 325 326bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old) { 327 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate(); 328 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate(); 329 330 // C++ [temp.fct]p2: 331 // A function template can be overloaded with other function templates 332 // and with normal (non-template) functions. 333 if ((OldTemplate == 0) != (NewTemplate == 0)) 334 return true; 335 336 // Is the function New an overload of the function Old? 337 QualType OldQType = Context.getCanonicalType(Old->getType()); 338 QualType NewQType = Context.getCanonicalType(New->getType()); 339 340 // Compare the signatures (C++ 1.3.10) of the two functions to 341 // determine whether they are overloads. If we find any mismatch 342 // in the signature, they are overloads. 343 344 // If either of these functions is a K&R-style function (no 345 // prototype), then we consider them to have matching signatures. 346 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 347 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 348 return false; 349 350 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType); 351 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType); 352 353 // The signature of a function includes the types of its 354 // parameters (C++ 1.3.10), which includes the presence or absence 355 // of the ellipsis; see C++ DR 357). 356 if (OldQType != NewQType && 357 (OldType->getNumArgs() != NewType->getNumArgs() || 358 OldType->isVariadic() != NewType->isVariadic() || 359 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 360 NewType->arg_type_begin()))) 361 return true; 362 363 // C++ [temp.over.link]p4: 364 // The signature of a function template consists of its function 365 // signature, its return type and its template parameter list. The names 366 // of the template parameters are significant only for establishing the 367 // relationship between the template parameters and the rest of the 368 // signature. 369 // 370 // We check the return type and template parameter lists for function 371 // templates first; the remaining checks follow. 372 if (NewTemplate && 373 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(), 374 OldTemplate->getTemplateParameters(), 375 false, TPL_TemplateMatch) || 376 OldType->getResultType() != NewType->getResultType())) 377 return true; 378 379 // If the function is a class member, its signature includes the 380 // cv-qualifiers (if any) on the function itself. 381 // 382 // As part of this, also check whether one of the member functions 383 // is static, in which case they are not overloads (C++ 384 // 13.1p2). While not part of the definition of the signature, 385 // this check is important to determine whether these functions 386 // can be overloaded. 387 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 388 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 389 if (OldMethod && NewMethod && 390 !OldMethod->isStatic() && !NewMethod->isStatic() && 391 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 392 return true; 393 394 // The signatures match; this is not an overload. 395 return false; 396} 397 398/// TryImplicitConversion - Attempt to perform an implicit conversion 399/// from the given expression (Expr) to the given type (ToType). This 400/// function returns an implicit conversion sequence that can be used 401/// to perform the initialization. Given 402/// 403/// void f(float f); 404/// void g(int i) { f(i); } 405/// 406/// this routine would produce an implicit conversion sequence to 407/// describe the initialization of f from i, which will be a standard 408/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 409/// 4.1) followed by a floating-integral conversion (C++ 4.9). 410// 411/// Note that this routine only determines how the conversion can be 412/// performed; it does not actually perform the conversion. As such, 413/// it will not produce any diagnostics if no conversion is available, 414/// but will instead return an implicit conversion sequence of kind 415/// "BadConversion". 416/// 417/// If @p SuppressUserConversions, then user-defined conversions are 418/// not permitted. 419/// If @p AllowExplicit, then explicit user-defined conversions are 420/// permitted. 421/// If @p ForceRValue, then overloading is performed as if From was an rvalue, 422/// no matter its actual lvalueness. 423/// If @p UserCast, the implicit conversion is being done for a user-specified 424/// cast. 425ImplicitConversionSequence 426Sema::TryImplicitConversion(Expr* From, QualType ToType, 427 bool SuppressUserConversions, 428 bool AllowExplicit, bool ForceRValue, 429 bool InOverloadResolution, 430 bool UserCast) { 431 ImplicitConversionSequence ICS; 432 OverloadCandidateSet Conversions; 433 OverloadingResult UserDefResult = OR_Success; 434 if (IsStandardConversion(From, ToType, InOverloadResolution, ICS.Standard)) 435 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 436 else if (getLangOptions().CPlusPlus && 437 (UserDefResult = IsUserDefinedConversion(From, ToType, 438 ICS.UserDefined, 439 Conversions, 440 !SuppressUserConversions, AllowExplicit, 441 ForceRValue, UserCast)) == OR_Success) { 442 ICS.ConversionKind = ImplicitConversionSequence::UserDefinedConversion; 443 // C++ [over.ics.user]p4: 444 // A conversion of an expression of class type to the same class 445 // type is given Exact Match rank, and a conversion of an 446 // expression of class type to a base class of that type is 447 // given Conversion rank, in spite of the fact that a copy 448 // constructor (i.e., a user-defined conversion function) is 449 // called for those cases. 450 if (CXXConstructorDecl *Constructor 451 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 452 QualType FromCanon 453 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 454 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 455 if (Constructor->isCopyConstructor() && 456 (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon))) { 457 // Turn this into a "standard" conversion sequence, so that it 458 // gets ranked with standard conversion sequences. 459 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 460 ICS.Standard.setAsIdentityConversion(); 461 ICS.Standard.FromTypePtr = From->getType().getAsOpaquePtr(); 462 ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr(); 463 ICS.Standard.CopyConstructor = Constructor; 464 if (ToCanon != FromCanon) 465 ICS.Standard.Second = ICK_Derived_To_Base; 466 } 467 } 468 469 // C++ [over.best.ics]p4: 470 // However, when considering the argument of a user-defined 471 // conversion function that is a candidate by 13.3.1.3 when 472 // invoked for the copying of the temporary in the second step 473 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 474 // 13.3.1.6 in all cases, only standard conversion sequences and 475 // ellipsis conversion sequences are allowed. 476 if (SuppressUserConversions && 477 ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion) 478 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 479 } else { 480 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 481 if (UserDefResult == OR_Ambiguous) { 482 for (OverloadCandidateSet::iterator Cand = Conversions.begin(); 483 Cand != Conversions.end(); ++Cand) 484 if (Cand->Viable) 485 ICS.ConversionFunctionSet.push_back(Cand->Function); 486 } 487 } 488 489 return ICS; 490} 491 492/// \brief Determine whether the conversion from FromType to ToType is a valid 493/// conversion that strips "noreturn" off the nested function type. 494static bool IsNoReturnConversion(ASTContext &Context, QualType FromType, 495 QualType ToType, QualType &ResultTy) { 496 if (Context.hasSameUnqualifiedType(FromType, ToType)) 497 return false; 498 499 // Strip the noreturn off the type we're converting from; noreturn can 500 // safely be removed. 501 FromType = Context.getNoReturnType(FromType, false); 502 if (!Context.hasSameUnqualifiedType(FromType, ToType)) 503 return false; 504 505 ResultTy = FromType; 506 return true; 507} 508 509/// IsStandardConversion - Determines whether there is a standard 510/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 511/// expression From to the type ToType. Standard conversion sequences 512/// only consider non-class types; for conversions that involve class 513/// types, use TryImplicitConversion. If a conversion exists, SCS will 514/// contain the standard conversion sequence required to perform this 515/// conversion and this routine will return true. Otherwise, this 516/// routine will return false and the value of SCS is unspecified. 517bool 518Sema::IsStandardConversion(Expr* From, QualType ToType, 519 bool InOverloadResolution, 520 StandardConversionSequence &SCS) { 521 QualType FromType = From->getType(); 522 523 // Standard conversions (C++ [conv]) 524 SCS.setAsIdentityConversion(); 525 SCS.Deprecated = false; 526 SCS.IncompatibleObjC = false; 527 SCS.FromTypePtr = FromType.getAsOpaquePtr(); 528 SCS.CopyConstructor = 0; 529 530 // There are no standard conversions for class types in C++, so 531 // abort early. When overloading in C, however, we do permit 532 if (FromType->isRecordType() || ToType->isRecordType()) { 533 if (getLangOptions().CPlusPlus) 534 return false; 535 536 // When we're overloading in C, we allow, as standard conversions, 537 } 538 539 // The first conversion can be an lvalue-to-rvalue conversion, 540 // array-to-pointer conversion, or function-to-pointer conversion 541 // (C++ 4p1). 542 543 // Lvalue-to-rvalue conversion (C++ 4.1): 544 // An lvalue (3.10) of a non-function, non-array type T can be 545 // converted to an rvalue. 546 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 547 if (argIsLvalue == Expr::LV_Valid && 548 !FromType->isFunctionType() && !FromType->isArrayType() && 549 Context.getCanonicalType(FromType) != Context.OverloadTy) { 550 SCS.First = ICK_Lvalue_To_Rvalue; 551 552 // If T is a non-class type, the type of the rvalue is the 553 // cv-unqualified version of T. Otherwise, the type of the rvalue 554 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 555 // just strip the qualifiers because they don't matter. 556 FromType = FromType.getUnqualifiedType(); 557 } else if (FromType->isArrayType()) { 558 // Array-to-pointer conversion (C++ 4.2) 559 SCS.First = ICK_Array_To_Pointer; 560 561 // An lvalue or rvalue of type "array of N T" or "array of unknown 562 // bound of T" can be converted to an rvalue of type "pointer to 563 // T" (C++ 4.2p1). 564 FromType = Context.getArrayDecayedType(FromType); 565 566 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 567 // This conversion is deprecated. (C++ D.4). 568 SCS.Deprecated = true; 569 570 // For the purpose of ranking in overload resolution 571 // (13.3.3.1.1), this conversion is considered an 572 // array-to-pointer conversion followed by a qualification 573 // conversion (4.4). (C++ 4.2p2) 574 SCS.Second = ICK_Identity; 575 SCS.Third = ICK_Qualification; 576 SCS.ToTypePtr = ToType.getAsOpaquePtr(); 577 return true; 578 } 579 } else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 580 // Function-to-pointer conversion (C++ 4.3). 581 SCS.First = ICK_Function_To_Pointer; 582 583 // An lvalue of function type T can be converted to an rvalue of 584 // type "pointer to T." The result is a pointer to the 585 // function. (C++ 4.3p1). 586 FromType = Context.getPointerType(FromType); 587 } else if (FunctionDecl *Fn 588 = ResolveAddressOfOverloadedFunction(From, ToType, false)) { 589 // Address of overloaded function (C++ [over.over]). 590 SCS.First = ICK_Function_To_Pointer; 591 592 // We were able to resolve the address of the overloaded function, 593 // so we can convert to the type of that function. 594 FromType = Fn->getType(); 595 if (ToType->isLValueReferenceType()) 596 FromType = Context.getLValueReferenceType(FromType); 597 else if (ToType->isRValueReferenceType()) 598 FromType = Context.getRValueReferenceType(FromType); 599 else if (ToType->isMemberPointerType()) { 600 // Resolve address only succeeds if both sides are member pointers, 601 // but it doesn't have to be the same class. See DR 247. 602 // Note that this means that the type of &Derived::fn can be 603 // Ret (Base::*)(Args) if the fn overload actually found is from the 604 // base class, even if it was brought into the derived class via a 605 // using declaration. The standard isn't clear on this issue at all. 606 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 607 FromType = Context.getMemberPointerType(FromType, 608 Context.getTypeDeclType(M->getParent()).getTypePtr()); 609 } else 610 FromType = Context.getPointerType(FromType); 611 } else { 612 // We don't require any conversions for the first step. 613 SCS.First = ICK_Identity; 614 } 615 616 // The second conversion can be an integral promotion, floating 617 // point promotion, integral conversion, floating point conversion, 618 // floating-integral conversion, pointer conversion, 619 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 620 // For overloading in C, this can also be a "compatible-type" 621 // conversion. 622 bool IncompatibleObjC = false; 623 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 624 // The unqualified versions of the types are the same: there's no 625 // conversion to do. 626 SCS.Second = ICK_Identity; 627 } else if (IsIntegralPromotion(From, FromType, ToType)) { 628 // Integral promotion (C++ 4.5). 629 SCS.Second = ICK_Integral_Promotion; 630 FromType = ToType.getUnqualifiedType(); 631 } else if (IsFloatingPointPromotion(FromType, ToType)) { 632 // Floating point promotion (C++ 4.6). 633 SCS.Second = ICK_Floating_Promotion; 634 FromType = ToType.getUnqualifiedType(); 635 } else if (IsComplexPromotion(FromType, ToType)) { 636 // Complex promotion (Clang extension) 637 SCS.Second = ICK_Complex_Promotion; 638 FromType = ToType.getUnqualifiedType(); 639 } else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 640 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 641 // Integral conversions (C++ 4.7). 642 // FIXME: isIntegralType shouldn't be true for enums in C++. 643 SCS.Second = ICK_Integral_Conversion; 644 FromType = ToType.getUnqualifiedType(); 645 } else if (FromType->isFloatingType() && ToType->isFloatingType()) { 646 // Floating point conversions (C++ 4.8). 647 SCS.Second = ICK_Floating_Conversion; 648 FromType = ToType.getUnqualifiedType(); 649 } else if (FromType->isComplexType() && ToType->isComplexType()) { 650 // Complex conversions (C99 6.3.1.6) 651 SCS.Second = ICK_Complex_Conversion; 652 FromType = ToType.getUnqualifiedType(); 653 } else if ((FromType->isFloatingType() && 654 ToType->isIntegralType() && (!ToType->isBooleanType() && 655 !ToType->isEnumeralType())) || 656 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 657 ToType->isFloatingType())) { 658 // Floating-integral conversions (C++ 4.9). 659 // FIXME: isIntegralType shouldn't be true for enums in C++. 660 SCS.Second = ICK_Floating_Integral; 661 FromType = ToType.getUnqualifiedType(); 662 } else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 663 (ToType->isComplexType() && FromType->isArithmeticType())) { 664 // Complex-real conversions (C99 6.3.1.7) 665 SCS.Second = ICK_Complex_Real; 666 FromType = ToType.getUnqualifiedType(); 667 } else if (IsPointerConversion(From, FromType, ToType, InOverloadResolution, 668 FromType, IncompatibleObjC)) { 669 // Pointer conversions (C++ 4.10). 670 SCS.Second = ICK_Pointer_Conversion; 671 SCS.IncompatibleObjC = IncompatibleObjC; 672 } else if (IsMemberPointerConversion(From, FromType, ToType, 673 InOverloadResolution, FromType)) { 674 // Pointer to member conversions (4.11). 675 SCS.Second = ICK_Pointer_Member; 676 } else if (ToType->isBooleanType() && 677 (FromType->isArithmeticType() || 678 FromType->isEnumeralType() || 679 FromType->isAnyPointerType() || 680 FromType->isBlockPointerType() || 681 FromType->isMemberPointerType() || 682 FromType->isNullPtrType())) { 683 // Boolean conversions (C++ 4.12). 684 SCS.Second = ICK_Boolean_Conversion; 685 FromType = Context.BoolTy; 686 } else if (!getLangOptions().CPlusPlus && 687 Context.typesAreCompatible(ToType, FromType)) { 688 // Compatible conversions (Clang extension for C function overloading) 689 SCS.Second = ICK_Compatible_Conversion; 690 } else if (IsNoReturnConversion(Context, FromType, ToType, FromType)) { 691 // Treat a conversion that strips "noreturn" as an identity conversion. 692 SCS.Second = ICK_NoReturn_Adjustment; 693 } else { 694 // No second conversion required. 695 SCS.Second = ICK_Identity; 696 } 697 698 QualType CanonFrom; 699 QualType CanonTo; 700 // The third conversion can be a qualification conversion (C++ 4p1). 701 if (IsQualificationConversion(FromType, ToType)) { 702 SCS.Third = ICK_Qualification; 703 FromType = ToType; 704 CanonFrom = Context.getCanonicalType(FromType); 705 CanonTo = Context.getCanonicalType(ToType); 706 } else { 707 // No conversion required 708 SCS.Third = ICK_Identity; 709 710 // C++ [over.best.ics]p6: 711 // [...] Any difference in top-level cv-qualification is 712 // subsumed by the initialization itself and does not constitute 713 // a conversion. [...] 714 CanonFrom = Context.getCanonicalType(FromType); 715 CanonTo = Context.getCanonicalType(ToType); 716 if (CanonFrom.getLocalUnqualifiedType() 717 == CanonTo.getLocalUnqualifiedType() && 718 CanonFrom.getLocalCVRQualifiers() != CanonTo.getLocalCVRQualifiers()) { 719 FromType = ToType; 720 CanonFrom = CanonTo; 721 } 722 } 723 724 // If we have not converted the argument type to the parameter type, 725 // this is a bad conversion sequence. 726 if (CanonFrom != CanonTo) 727 return false; 728 729 SCS.ToTypePtr = FromType.getAsOpaquePtr(); 730 return true; 731} 732 733/// IsIntegralPromotion - Determines whether the conversion from the 734/// expression From (whose potentially-adjusted type is FromType) to 735/// ToType is an integral promotion (C++ 4.5). If so, returns true and 736/// sets PromotedType to the promoted type. 737bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) { 738 const BuiltinType *To = ToType->getAs<BuiltinType>(); 739 // All integers are built-in. 740 if (!To) { 741 return false; 742 } 743 744 // An rvalue of type char, signed char, unsigned char, short int, or 745 // unsigned short int can be converted to an rvalue of type int if 746 // int can represent all the values of the source type; otherwise, 747 // the source rvalue can be converted to an rvalue of type unsigned 748 // int (C++ 4.5p1). 749 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType()) { 750 if (// We can promote any signed, promotable integer type to an int 751 (FromType->isSignedIntegerType() || 752 // We can promote any unsigned integer type whose size is 753 // less than int to an int. 754 (!FromType->isSignedIntegerType() && 755 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 756 return To->getKind() == BuiltinType::Int; 757 } 758 759 return To->getKind() == BuiltinType::UInt; 760 } 761 762 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 763 // can be converted to an rvalue of the first of the following types 764 // that can represent all the values of its underlying type: int, 765 // unsigned int, long, or unsigned long (C++ 4.5p2). 766 767 // We pre-calculate the promotion type for enum types. 768 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) 769 if (ToType->isIntegerType()) 770 return Context.hasSameUnqualifiedType(ToType, 771 FromEnumType->getDecl()->getPromotionType()); 772 773 if (FromType->isWideCharType() && ToType->isIntegerType()) { 774 // Determine whether the type we're converting from is signed or 775 // unsigned. 776 bool FromIsSigned; 777 uint64_t FromSize = Context.getTypeSize(FromType); 778 779 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 780 FromIsSigned = true; 781 782 // The types we'll try to promote to, in the appropriate 783 // order. Try each of these types. 784 QualType PromoteTypes[6] = { 785 Context.IntTy, Context.UnsignedIntTy, 786 Context.LongTy, Context.UnsignedLongTy , 787 Context.LongLongTy, Context.UnsignedLongLongTy 788 }; 789 for (int Idx = 0; Idx < 6; ++Idx) { 790 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 791 if (FromSize < ToSize || 792 (FromSize == ToSize && 793 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 794 // We found the type that we can promote to. If this is the 795 // type we wanted, we have a promotion. Otherwise, no 796 // promotion. 797 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]); 798 } 799 } 800 } 801 802 // An rvalue for an integral bit-field (9.6) can be converted to an 803 // rvalue of type int if int can represent all the values of the 804 // bit-field; otherwise, it can be converted to unsigned int if 805 // unsigned int can represent all the values of the bit-field. If 806 // the bit-field is larger yet, no integral promotion applies to 807 // it. If the bit-field has an enumerated type, it is treated as any 808 // other value of that type for promotion purposes (C++ 4.5p3). 809 // FIXME: We should delay checking of bit-fields until we actually perform the 810 // conversion. 811 using llvm::APSInt; 812 if (From) 813 if (FieldDecl *MemberDecl = From->getBitField()) { 814 APSInt BitWidth; 815 if (FromType->isIntegralType() && !FromType->isEnumeralType() && 816 MemberDecl->getBitWidth()->isIntegerConstantExpr(BitWidth, Context)) { 817 APSInt ToSize(BitWidth.getBitWidth(), BitWidth.isUnsigned()); 818 ToSize = Context.getTypeSize(ToType); 819 820 // Are we promoting to an int from a bitfield that fits in an int? 821 if (BitWidth < ToSize || 822 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 823 return To->getKind() == BuiltinType::Int; 824 } 825 826 // Are we promoting to an unsigned int from an unsigned bitfield 827 // that fits into an unsigned int? 828 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 829 return To->getKind() == BuiltinType::UInt; 830 } 831 832 return false; 833 } 834 } 835 836 // An rvalue of type bool can be converted to an rvalue of type int, 837 // with false becoming zero and true becoming one (C++ 4.5p4). 838 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 839 return true; 840 } 841 842 return false; 843} 844 845/// IsFloatingPointPromotion - Determines whether the conversion from 846/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 847/// returns true and sets PromotedType to the promoted type. 848bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) { 849 /// An rvalue of type float can be converted to an rvalue of type 850 /// double. (C++ 4.6p1). 851 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>()) 852 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) { 853 if (FromBuiltin->getKind() == BuiltinType::Float && 854 ToBuiltin->getKind() == BuiltinType::Double) 855 return true; 856 857 // C99 6.3.1.5p1: 858 // When a float is promoted to double or long double, or a 859 // double is promoted to long double [...]. 860 if (!getLangOptions().CPlusPlus && 861 (FromBuiltin->getKind() == BuiltinType::Float || 862 FromBuiltin->getKind() == BuiltinType::Double) && 863 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 864 return true; 865 } 866 867 return false; 868} 869 870/// \brief Determine if a conversion is a complex promotion. 871/// 872/// A complex promotion is defined as a complex -> complex conversion 873/// where the conversion between the underlying real types is a 874/// floating-point or integral promotion. 875bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 876 const ComplexType *FromComplex = FromType->getAs<ComplexType>(); 877 if (!FromComplex) 878 return false; 879 880 const ComplexType *ToComplex = ToType->getAs<ComplexType>(); 881 if (!ToComplex) 882 return false; 883 884 return IsFloatingPointPromotion(FromComplex->getElementType(), 885 ToComplex->getElementType()) || 886 IsIntegralPromotion(0, FromComplex->getElementType(), 887 ToComplex->getElementType()); 888} 889 890/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 891/// the pointer type FromPtr to a pointer to type ToPointee, with the 892/// same type qualifiers as FromPtr has on its pointee type. ToType, 893/// if non-empty, will be a pointer to ToType that may or may not have 894/// the right set of qualifiers on its pointee. 895static QualType 896BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 897 QualType ToPointee, QualType ToType, 898 ASTContext &Context) { 899 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 900 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 901 Qualifiers Quals = CanonFromPointee.getQualifiers(); 902 903 // Exact qualifier match -> return the pointer type we're converting to. 904 if (CanonToPointee.getLocalQualifiers() == Quals) { 905 // ToType is exactly what we need. Return it. 906 if (!ToType.isNull()) 907 return ToType; 908 909 // Build a pointer to ToPointee. It has the right qualifiers 910 // already. 911 return Context.getPointerType(ToPointee); 912 } 913 914 // Just build a canonical type that has the right qualifiers. 915 return Context.getPointerType( 916 Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), 917 Quals)); 918} 919 920/// BuildSimilarlyQualifiedObjCObjectPointerType - In a pointer conversion from 921/// the FromType, which is an objective-c pointer, to ToType, which may or may 922/// not have the right set of qualifiers. 923static QualType 924BuildSimilarlyQualifiedObjCObjectPointerType(QualType FromType, 925 QualType ToType, 926 ASTContext &Context) { 927 QualType CanonFromType = Context.getCanonicalType(FromType); 928 QualType CanonToType = Context.getCanonicalType(ToType); 929 Qualifiers Quals = CanonFromType.getQualifiers(); 930 931 // Exact qualifier match -> return the pointer type we're converting to. 932 if (CanonToType.getLocalQualifiers() == Quals) 933 return ToType; 934 935 // Just build a canonical type that has the right qualifiers. 936 return Context.getQualifiedType(CanonToType.getLocalUnqualifiedType(), Quals); 937} 938 939static bool isNullPointerConstantForConversion(Expr *Expr, 940 bool InOverloadResolution, 941 ASTContext &Context) { 942 // Handle value-dependent integral null pointer constants correctly. 943 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903 944 if (Expr->isValueDependent() && !Expr->isTypeDependent() && 945 Expr->getType()->isIntegralType()) 946 return !InOverloadResolution; 947 948 return Expr->isNullPointerConstant(Context, 949 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 950 : Expr::NPC_ValueDependentIsNull); 951} 952 953/// IsPointerConversion - Determines whether the conversion of the 954/// expression From, which has the (possibly adjusted) type FromType, 955/// can be converted to the type ToType via a pointer conversion (C++ 956/// 4.10). If so, returns true and places the converted type (that 957/// might differ from ToType in its cv-qualifiers at some level) into 958/// ConvertedType. 959/// 960/// This routine also supports conversions to and from block pointers 961/// and conversions with Objective-C's 'id', 'id<protocols...>', and 962/// pointers to interfaces. FIXME: Once we've determined the 963/// appropriate overloading rules for Objective-C, we may want to 964/// split the Objective-C checks into a different routine; however, 965/// GCC seems to consider all of these conversions to be pointer 966/// conversions, so for now they live here. IncompatibleObjC will be 967/// set if the conversion is an allowed Objective-C conversion that 968/// should result in a warning. 969bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 970 bool InOverloadResolution, 971 QualType& ConvertedType, 972 bool &IncompatibleObjC) { 973 IncompatibleObjC = false; 974 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 975 return true; 976 977 // Conversion from a null pointer constant to any Objective-C pointer type. 978 if (ToType->isObjCObjectPointerType() && 979 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 980 ConvertedType = ToType; 981 return true; 982 } 983 984 // Blocks: Block pointers can be converted to void*. 985 if (FromType->isBlockPointerType() && ToType->isPointerType() && 986 ToType->getAs<PointerType>()->getPointeeType()->isVoidType()) { 987 ConvertedType = ToType; 988 return true; 989 } 990 // Blocks: A null pointer constant can be converted to a block 991 // pointer type. 992 if (ToType->isBlockPointerType() && 993 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 994 ConvertedType = ToType; 995 return true; 996 } 997 998 // If the left-hand-side is nullptr_t, the right side can be a null 999 // pointer constant. 1000 if (ToType->isNullPtrType() && 1001 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1002 ConvertedType = ToType; 1003 return true; 1004 } 1005 1006 const PointerType* ToTypePtr = ToType->getAs<PointerType>(); 1007 if (!ToTypePtr) 1008 return false; 1009 1010 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 1011 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) { 1012 ConvertedType = ToType; 1013 return true; 1014 } 1015 1016 // Beyond this point, both types need to be pointers 1017 // , including objective-c pointers. 1018 QualType ToPointeeType = ToTypePtr->getPointeeType(); 1019 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType()) { 1020 ConvertedType = BuildSimilarlyQualifiedObjCObjectPointerType(FromType, 1021 ToType, Context); 1022 return true; 1023 1024 } 1025 const PointerType *FromTypePtr = FromType->getAs<PointerType>(); 1026 if (!FromTypePtr) 1027 return false; 1028 1029 QualType FromPointeeType = FromTypePtr->getPointeeType(); 1030 1031 // An rvalue of type "pointer to cv T," where T is an object type, 1032 // can be converted to an rvalue of type "pointer to cv void" (C++ 1033 // 4.10p2). 1034 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 1035 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1036 ToPointeeType, 1037 ToType, Context); 1038 return true; 1039 } 1040 1041 // When we're overloading in C, we allow a special kind of pointer 1042 // conversion for compatible-but-not-identical pointee types. 1043 if (!getLangOptions().CPlusPlus && 1044 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 1045 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1046 ToPointeeType, 1047 ToType, Context); 1048 return true; 1049 } 1050 1051 // C++ [conv.ptr]p3: 1052 // 1053 // An rvalue of type "pointer to cv D," where D is a class type, 1054 // can be converted to an rvalue of type "pointer to cv B," where 1055 // B is a base class (clause 10) of D. If B is an inaccessible 1056 // (clause 11) or ambiguous (10.2) base class of D, a program that 1057 // necessitates this conversion is ill-formed. The result of the 1058 // conversion is a pointer to the base class sub-object of the 1059 // derived class object. The null pointer value is converted to 1060 // the null pointer value of the destination type. 1061 // 1062 // Note that we do not check for ambiguity or inaccessibility 1063 // here. That is handled by CheckPointerConversion. 1064 if (getLangOptions().CPlusPlus && 1065 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 1066 !RequireCompleteType(From->getLocStart(), FromPointeeType, PDiag()) && 1067 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 1068 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1069 ToPointeeType, 1070 ToType, Context); 1071 return true; 1072 } 1073 1074 return false; 1075} 1076 1077/// isObjCPointerConversion - Determines whether this is an 1078/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 1079/// with the same arguments and return values. 1080bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 1081 QualType& ConvertedType, 1082 bool &IncompatibleObjC) { 1083 if (!getLangOptions().ObjC1) 1084 return false; 1085 1086 // First, we handle all conversions on ObjC object pointer types. 1087 const ObjCObjectPointerType* ToObjCPtr = ToType->getAs<ObjCObjectPointerType>(); 1088 const ObjCObjectPointerType *FromObjCPtr = 1089 FromType->getAs<ObjCObjectPointerType>(); 1090 1091 if (ToObjCPtr && FromObjCPtr) { 1092 // Objective C++: We're able to convert between "id" or "Class" and a 1093 // pointer to any interface (in both directions). 1094 if (ToObjCPtr->isObjCBuiltinType() && FromObjCPtr->isObjCBuiltinType()) { 1095 ConvertedType = ToType; 1096 return true; 1097 } 1098 // Conversions with Objective-C's id<...>. 1099 if ((FromObjCPtr->isObjCQualifiedIdType() || 1100 ToObjCPtr->isObjCQualifiedIdType()) && 1101 Context.ObjCQualifiedIdTypesAreCompatible(ToType, FromType, 1102 /*compare=*/false)) { 1103 ConvertedType = ToType; 1104 return true; 1105 } 1106 // Objective C++: We're able to convert from a pointer to an 1107 // interface to a pointer to a different interface. 1108 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) { 1109 ConvertedType = ToType; 1110 return true; 1111 } 1112 1113 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) { 1114 // Okay: this is some kind of implicit downcast of Objective-C 1115 // interfaces, which is permitted. However, we're going to 1116 // complain about it. 1117 IncompatibleObjC = true; 1118 ConvertedType = FromType; 1119 return true; 1120 } 1121 } 1122 // Beyond this point, both types need to be C pointers or block pointers. 1123 QualType ToPointeeType; 1124 if (const PointerType *ToCPtr = ToType->getAs<PointerType>()) 1125 ToPointeeType = ToCPtr->getPointeeType(); 1126 else if (const BlockPointerType *ToBlockPtr = ToType->getAs<BlockPointerType>()) 1127 ToPointeeType = ToBlockPtr->getPointeeType(); 1128 else 1129 return false; 1130 1131 QualType FromPointeeType; 1132 if (const PointerType *FromCPtr = FromType->getAs<PointerType>()) 1133 FromPointeeType = FromCPtr->getPointeeType(); 1134 else if (const BlockPointerType *FromBlockPtr = FromType->getAs<BlockPointerType>()) 1135 FromPointeeType = FromBlockPtr->getPointeeType(); 1136 else 1137 return false; 1138 1139 // If we have pointers to pointers, recursively check whether this 1140 // is an Objective-C conversion. 1141 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1142 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1143 IncompatibleObjC)) { 1144 // We always complain about this conversion. 1145 IncompatibleObjC = true; 1146 ConvertedType = ToType; 1147 return true; 1148 } 1149 // If we have pointers to functions or blocks, check whether the only 1150 // differences in the argument and result types are in Objective-C 1151 // pointer conversions. If so, we permit the conversion (but 1152 // complain about it). 1153 const FunctionProtoType *FromFunctionType 1154 = FromPointeeType->getAs<FunctionProtoType>(); 1155 const FunctionProtoType *ToFunctionType 1156 = ToPointeeType->getAs<FunctionProtoType>(); 1157 if (FromFunctionType && ToFunctionType) { 1158 // If the function types are exactly the same, this isn't an 1159 // Objective-C pointer conversion. 1160 if (Context.getCanonicalType(FromPointeeType) 1161 == Context.getCanonicalType(ToPointeeType)) 1162 return false; 1163 1164 // Perform the quick checks that will tell us whether these 1165 // function types are obviously different. 1166 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1167 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1168 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1169 return false; 1170 1171 bool HasObjCConversion = false; 1172 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1173 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1174 // Okay, the types match exactly. Nothing to do. 1175 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1176 ToFunctionType->getResultType(), 1177 ConvertedType, IncompatibleObjC)) { 1178 // Okay, we have an Objective-C pointer conversion. 1179 HasObjCConversion = true; 1180 } else { 1181 // Function types are too different. Abort. 1182 return false; 1183 } 1184 1185 // Check argument types. 1186 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1187 ArgIdx != NumArgs; ++ArgIdx) { 1188 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1189 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1190 if (Context.getCanonicalType(FromArgType) 1191 == Context.getCanonicalType(ToArgType)) { 1192 // Okay, the types match exactly. Nothing to do. 1193 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1194 ConvertedType, IncompatibleObjC)) { 1195 // Okay, we have an Objective-C pointer conversion. 1196 HasObjCConversion = true; 1197 } else { 1198 // Argument types are too different. Abort. 1199 return false; 1200 } 1201 } 1202 1203 if (HasObjCConversion) { 1204 // We had an Objective-C conversion. Allow this pointer 1205 // conversion, but complain about it. 1206 ConvertedType = ToType; 1207 IncompatibleObjC = true; 1208 return true; 1209 } 1210 } 1211 1212 return false; 1213} 1214 1215/// CheckPointerConversion - Check the pointer conversion from the 1216/// expression From to the type ToType. This routine checks for 1217/// ambiguous or inaccessible derived-to-base pointer 1218/// conversions for which IsPointerConversion has already returned 1219/// true. It returns true and produces a diagnostic if there was an 1220/// error, or returns false otherwise. 1221bool Sema::CheckPointerConversion(Expr *From, QualType ToType, 1222 CastExpr::CastKind &Kind, 1223 bool IgnoreBaseAccess) { 1224 QualType FromType = From->getType(); 1225 1226 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) 1227 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) { 1228 QualType FromPointeeType = FromPtrType->getPointeeType(), 1229 ToPointeeType = ToPtrType->getPointeeType(); 1230 1231 if (FromPointeeType->isRecordType() && 1232 ToPointeeType->isRecordType()) { 1233 // We must have a derived-to-base conversion. Check an 1234 // ambiguous or inaccessible conversion. 1235 if (CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1236 From->getExprLoc(), 1237 From->getSourceRange(), 1238 IgnoreBaseAccess)) 1239 return true; 1240 1241 // The conversion was successful. 1242 Kind = CastExpr::CK_DerivedToBase; 1243 } 1244 } 1245 if (const ObjCObjectPointerType *FromPtrType = 1246 FromType->getAs<ObjCObjectPointerType>()) 1247 if (const ObjCObjectPointerType *ToPtrType = 1248 ToType->getAs<ObjCObjectPointerType>()) { 1249 // Objective-C++ conversions are always okay. 1250 // FIXME: We should have a different class of conversions for the 1251 // Objective-C++ implicit conversions. 1252 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType()) 1253 return false; 1254 1255 } 1256 return false; 1257} 1258 1259/// IsMemberPointerConversion - Determines whether the conversion of the 1260/// expression From, which has the (possibly adjusted) type FromType, can be 1261/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1262/// If so, returns true and places the converted type (that might differ from 1263/// ToType in its cv-qualifiers at some level) into ConvertedType. 1264bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1265 QualType ToType, 1266 bool InOverloadResolution, 1267 QualType &ConvertedType) { 1268 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>(); 1269 if (!ToTypePtr) 1270 return false; 1271 1272 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1273 if (From->isNullPointerConstant(Context, 1274 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull 1275 : Expr::NPC_ValueDependentIsNull)) { 1276 ConvertedType = ToType; 1277 return true; 1278 } 1279 1280 // Otherwise, both types have to be member pointers. 1281 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>(); 1282 if (!FromTypePtr) 1283 return false; 1284 1285 // A pointer to member of B can be converted to a pointer to member of D, 1286 // where D is derived from B (C++ 4.11p2). 1287 QualType FromClass(FromTypePtr->getClass(), 0); 1288 QualType ToClass(ToTypePtr->getClass(), 0); 1289 // FIXME: What happens when these are dependent? Is this function even called? 1290 1291 if (IsDerivedFrom(ToClass, FromClass)) { 1292 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1293 ToClass.getTypePtr()); 1294 return true; 1295 } 1296 1297 return false; 1298} 1299 1300/// CheckMemberPointerConversion - Check the member pointer conversion from the 1301/// expression From to the type ToType. This routine checks for ambiguous or 1302/// virtual (FIXME: or inaccessible) base-to-derived member pointer conversions 1303/// for which IsMemberPointerConversion has already returned true. It returns 1304/// true and produces a diagnostic if there was an error, or returns false 1305/// otherwise. 1306bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType, 1307 CastExpr::CastKind &Kind, 1308 bool IgnoreBaseAccess) { 1309 (void)IgnoreBaseAccess; 1310 QualType FromType = From->getType(); 1311 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>(); 1312 if (!FromPtrType) { 1313 // This must be a null pointer to member pointer conversion 1314 assert(From->isNullPointerConstant(Context, 1315 Expr::NPC_ValueDependentIsNull) && 1316 "Expr must be null pointer constant!"); 1317 Kind = CastExpr::CK_NullToMemberPointer; 1318 return false; 1319 } 1320 1321 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>(); 1322 assert(ToPtrType && "No member pointer cast has a target type " 1323 "that is not a member pointer."); 1324 1325 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1326 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1327 1328 // FIXME: What about dependent types? 1329 assert(FromClass->isRecordType() && "Pointer into non-class."); 1330 assert(ToClass->isRecordType() && "Pointer into non-class."); 1331 1332 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, 1333 /*DetectVirtual=*/true); 1334 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1335 assert(DerivationOkay && 1336 "Should not have been called if derivation isn't OK."); 1337 (void)DerivationOkay; 1338 1339 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1340 getUnqualifiedType())) { 1341 // Derivation is ambiguous. Redo the check to find the exact paths. 1342 Paths.clear(); 1343 Paths.setRecordingPaths(true); 1344 bool StillOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1345 assert(StillOkay && "Derivation changed due to quantum fluctuation."); 1346 (void)StillOkay; 1347 1348 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1349 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1350 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1351 return true; 1352 } 1353 1354 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1355 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1356 << FromClass << ToClass << QualType(VBase, 0) 1357 << From->getSourceRange(); 1358 return true; 1359 } 1360 1361 // Must be a base to derived member conversion. 1362 Kind = CastExpr::CK_BaseToDerivedMemberPointer; 1363 return false; 1364} 1365 1366/// IsQualificationConversion - Determines whether the conversion from 1367/// an rvalue of type FromType to ToType is a qualification conversion 1368/// (C++ 4.4). 1369bool 1370Sema::IsQualificationConversion(QualType FromType, QualType ToType) { 1371 FromType = Context.getCanonicalType(FromType); 1372 ToType = Context.getCanonicalType(ToType); 1373 1374 // If FromType and ToType are the same type, this is not a 1375 // qualification conversion. 1376 if (FromType == ToType) 1377 return false; 1378 1379 // (C++ 4.4p4): 1380 // A conversion can add cv-qualifiers at levels other than the first 1381 // in multi-level pointers, subject to the following rules: [...] 1382 bool PreviousToQualsIncludeConst = true; 1383 bool UnwrappedAnyPointer = false; 1384 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1385 // Within each iteration of the loop, we check the qualifiers to 1386 // determine if this still looks like a qualification 1387 // conversion. Then, if all is well, we unwrap one more level of 1388 // pointers or pointers-to-members and do it all again 1389 // until there are no more pointers or pointers-to-members left to 1390 // unwrap. 1391 UnwrappedAnyPointer = true; 1392 1393 // -- for every j > 0, if const is in cv 1,j then const is in cv 1394 // 2,j, and similarly for volatile. 1395 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1396 return false; 1397 1398 // -- if the cv 1,j and cv 2,j are different, then const is in 1399 // every cv for 0 < k < j. 1400 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1401 && !PreviousToQualsIncludeConst) 1402 return false; 1403 1404 // Keep track of whether all prior cv-qualifiers in the "to" type 1405 // include const. 1406 PreviousToQualsIncludeConst 1407 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1408 } 1409 1410 // We are left with FromType and ToType being the pointee types 1411 // after unwrapping the original FromType and ToType the same number 1412 // of types. If we unwrapped any pointers, and if FromType and 1413 // ToType have the same unqualified type (since we checked 1414 // qualifiers above), then this is a qualification conversion. 1415 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType); 1416} 1417 1418/// Determines whether there is a user-defined conversion sequence 1419/// (C++ [over.ics.user]) that converts expression From to the type 1420/// ToType. If such a conversion exists, User will contain the 1421/// user-defined conversion sequence that performs such a conversion 1422/// and this routine will return true. Otherwise, this routine returns 1423/// false and User is unspecified. 1424/// 1425/// \param AllowConversionFunctions true if the conversion should 1426/// consider conversion functions at all. If false, only constructors 1427/// will be considered. 1428/// 1429/// \param AllowExplicit true if the conversion should consider C++0x 1430/// "explicit" conversion functions as well as non-explicit conversion 1431/// functions (C++0x [class.conv.fct]p2). 1432/// 1433/// \param ForceRValue true if the expression should be treated as an rvalue 1434/// for overload resolution. 1435/// \param UserCast true if looking for user defined conversion for a static 1436/// cast. 1437OverloadingResult Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1438 UserDefinedConversionSequence& User, 1439 OverloadCandidateSet& CandidateSet, 1440 bool AllowConversionFunctions, 1441 bool AllowExplicit, 1442 bool ForceRValue, 1443 bool UserCast) { 1444 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) { 1445 if (RequireCompleteType(From->getLocStart(), ToType, PDiag())) { 1446 // We're not going to find any constructors. 1447 } else if (CXXRecordDecl *ToRecordDecl 1448 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1449 // C++ [over.match.ctor]p1: 1450 // When objects of class type are direct-initialized (8.5), or 1451 // copy-initialized from an expression of the same or a 1452 // derived class type (8.5), overload resolution selects the 1453 // constructor. [...] For copy-initialization, the candidate 1454 // functions are all the converting constructors (12.3.1) of 1455 // that class. The argument list is the expression-list within 1456 // the parentheses of the initializer. 1457 bool SuppressUserConversions = !UserCast; 1458 if (Context.hasSameUnqualifiedType(ToType, From->getType()) || 1459 IsDerivedFrom(From->getType(), ToType)) { 1460 SuppressUserConversions = false; 1461 AllowConversionFunctions = false; 1462 } 1463 1464 DeclarationName ConstructorName 1465 = Context.DeclarationNames.getCXXConstructorName( 1466 Context.getCanonicalType(ToType).getUnqualifiedType()); 1467 DeclContext::lookup_iterator Con, ConEnd; 1468 for (llvm::tie(Con, ConEnd) 1469 = ToRecordDecl->lookup(ConstructorName); 1470 Con != ConEnd; ++Con) { 1471 // Find the constructor (which may be a template). 1472 CXXConstructorDecl *Constructor = 0; 1473 FunctionTemplateDecl *ConstructorTmpl 1474 = dyn_cast<FunctionTemplateDecl>(*Con); 1475 if (ConstructorTmpl) 1476 Constructor 1477 = cast<CXXConstructorDecl>(ConstructorTmpl->getTemplatedDecl()); 1478 else 1479 Constructor = cast<CXXConstructorDecl>(*Con); 1480 1481 if (!Constructor->isInvalidDecl() && 1482 Constructor->isConvertingConstructor(AllowExplicit)) { 1483 if (ConstructorTmpl) 1484 AddTemplateOverloadCandidate(ConstructorTmpl, /*ExplicitArgs*/ 0, 1485 &From, 1, CandidateSet, 1486 SuppressUserConversions, ForceRValue); 1487 else 1488 // Allow one user-defined conversion when user specifies a 1489 // From->ToType conversion via an static cast (c-style, etc). 1490 AddOverloadCandidate(Constructor, &From, 1, CandidateSet, 1491 SuppressUserConversions, ForceRValue); 1492 } 1493 } 1494 } 1495 } 1496 1497 if (!AllowConversionFunctions) { 1498 // Don't allow any conversion functions to enter the overload set. 1499 } else if (RequireCompleteType(From->getLocStart(), From->getType(), 1500 PDiag(0) 1501 << From->getSourceRange())) { 1502 // No conversion functions from incomplete types. 1503 } else if (const RecordType *FromRecordType 1504 = From->getType()->getAs<RecordType>()) { 1505 if (CXXRecordDecl *FromRecordDecl 1506 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1507 // Add all of the conversion functions as candidates. 1508 const UnresolvedSet *Conversions 1509 = FromRecordDecl->getVisibleConversionFunctions(); 1510 for (UnresolvedSet::iterator I = Conversions->begin(), 1511 E = Conversions->end(); I != E; ++I) { 1512 NamedDecl *D = *I; 1513 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 1514 if (isa<UsingShadowDecl>(D)) 1515 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 1516 1517 CXXConversionDecl *Conv; 1518 FunctionTemplateDecl *ConvTemplate; 1519 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(*I))) 1520 Conv = dyn_cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl()); 1521 else 1522 Conv = dyn_cast<CXXConversionDecl>(*I); 1523 1524 if (AllowExplicit || !Conv->isExplicit()) { 1525 if (ConvTemplate) 1526 AddTemplateConversionCandidate(ConvTemplate, ActingContext, 1527 From, ToType, CandidateSet); 1528 else 1529 AddConversionCandidate(Conv, ActingContext, From, ToType, 1530 CandidateSet); 1531 } 1532 } 1533 } 1534 } 1535 1536 OverloadCandidateSet::iterator Best; 1537 switch (BestViableFunction(CandidateSet, From->getLocStart(), Best)) { 1538 case OR_Success: 1539 // Record the standard conversion we used and the conversion function. 1540 if (CXXConstructorDecl *Constructor 1541 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1542 // C++ [over.ics.user]p1: 1543 // If the user-defined conversion is specified by a 1544 // constructor (12.3.1), the initial standard conversion 1545 // sequence converts the source type to the type required by 1546 // the argument of the constructor. 1547 // 1548 QualType ThisType = Constructor->getThisType(Context); 1549 if (Best->Conversions[0].ConversionKind == 1550 ImplicitConversionSequence::EllipsisConversion) 1551 User.EllipsisConversion = true; 1552 else { 1553 User.Before = Best->Conversions[0].Standard; 1554 User.EllipsisConversion = false; 1555 } 1556 User.ConversionFunction = Constructor; 1557 User.After.setAsIdentityConversion(); 1558 User.After.FromTypePtr 1559 = ThisType->getAs<PointerType>()->getPointeeType().getAsOpaquePtr(); 1560 User.After.ToTypePtr = ToType.getAsOpaquePtr(); 1561 return OR_Success; 1562 } else if (CXXConversionDecl *Conversion 1563 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1564 // C++ [over.ics.user]p1: 1565 // 1566 // [...] If the user-defined conversion is specified by a 1567 // conversion function (12.3.2), the initial standard 1568 // conversion sequence converts the source type to the 1569 // implicit object parameter of the conversion function. 1570 User.Before = Best->Conversions[0].Standard; 1571 User.ConversionFunction = Conversion; 1572 User.EllipsisConversion = false; 1573 1574 // C++ [over.ics.user]p2: 1575 // The second standard conversion sequence converts the 1576 // result of the user-defined conversion to the target type 1577 // for the sequence. Since an implicit conversion sequence 1578 // is an initialization, the special rules for 1579 // initialization by user-defined conversion apply when 1580 // selecting the best user-defined conversion for a 1581 // user-defined conversion sequence (see 13.3.3 and 1582 // 13.3.3.1). 1583 User.After = Best->FinalConversion; 1584 return OR_Success; 1585 } else { 1586 assert(false && "Not a constructor or conversion function?"); 1587 return OR_No_Viable_Function; 1588 } 1589 1590 case OR_No_Viable_Function: 1591 return OR_No_Viable_Function; 1592 case OR_Deleted: 1593 // No conversion here! We're done. 1594 return OR_Deleted; 1595 1596 case OR_Ambiguous: 1597 return OR_Ambiguous; 1598 } 1599 1600 return OR_No_Viable_Function; 1601} 1602 1603bool 1604Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) { 1605 ImplicitConversionSequence ICS; 1606 OverloadCandidateSet CandidateSet; 1607 OverloadingResult OvResult = 1608 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 1609 CandidateSet, true, false, false); 1610 if (OvResult == OR_Ambiguous) 1611 Diag(From->getSourceRange().getBegin(), 1612 diag::err_typecheck_ambiguous_condition) 1613 << From->getType() << ToType << From->getSourceRange(); 1614 else if (OvResult == OR_No_Viable_Function && !CandidateSet.empty()) 1615 Diag(From->getSourceRange().getBegin(), 1616 diag::err_typecheck_nonviable_condition) 1617 << From->getType() << ToType << From->getSourceRange(); 1618 else 1619 return false; 1620 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 1621 return true; 1622} 1623 1624/// CompareImplicitConversionSequences - Compare two implicit 1625/// conversion sequences to determine whether one is better than the 1626/// other or if they are indistinguishable (C++ 13.3.3.2). 1627ImplicitConversionSequence::CompareKind 1628Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1629 const ImplicitConversionSequence& ICS2) 1630{ 1631 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1632 // conversion sequences (as defined in 13.3.3.1) 1633 // -- a standard conversion sequence (13.3.3.1.1) is a better 1634 // conversion sequence than a user-defined conversion sequence or 1635 // an ellipsis conversion sequence, and 1636 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1637 // conversion sequence than an ellipsis conversion sequence 1638 // (13.3.3.1.3). 1639 // 1640 if (ICS1.ConversionKind < ICS2.ConversionKind) 1641 return ImplicitConversionSequence::Better; 1642 else if (ICS2.ConversionKind < ICS1.ConversionKind) 1643 return ImplicitConversionSequence::Worse; 1644 1645 // Two implicit conversion sequences of the same form are 1646 // indistinguishable conversion sequences unless one of the 1647 // following rules apply: (C++ 13.3.3.2p3): 1648 if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion) 1649 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1650 else if (ICS1.ConversionKind == 1651 ImplicitConversionSequence::UserDefinedConversion) { 1652 // User-defined conversion sequence U1 is a better conversion 1653 // sequence than another user-defined conversion sequence U2 if 1654 // they contain the same user-defined conversion function or 1655 // constructor and if the second standard conversion sequence of 1656 // U1 is better than the second standard conversion sequence of 1657 // U2 (C++ 13.3.3.2p3). 1658 if (ICS1.UserDefined.ConversionFunction == 1659 ICS2.UserDefined.ConversionFunction) 1660 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1661 ICS2.UserDefined.After); 1662 } 1663 1664 return ImplicitConversionSequence::Indistinguishable; 1665} 1666 1667/// CompareStandardConversionSequences - Compare two standard 1668/// conversion sequences to determine whether one is better than the 1669/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1670ImplicitConversionSequence::CompareKind 1671Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1672 const StandardConversionSequence& SCS2) 1673{ 1674 // Standard conversion sequence S1 is a better conversion sequence 1675 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1676 1677 // -- S1 is a proper subsequence of S2 (comparing the conversion 1678 // sequences in the canonical form defined by 13.3.3.1.1, 1679 // excluding any Lvalue Transformation; the identity conversion 1680 // sequence is considered to be a subsequence of any 1681 // non-identity conversion sequence) or, if not that, 1682 if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third) 1683 // Neither is a proper subsequence of the other. Do nothing. 1684 ; 1685 else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) || 1686 (SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) || 1687 (SCS1.Second == ICK_Identity && 1688 SCS1.Third == ICK_Identity)) 1689 // SCS1 is a proper subsequence of SCS2. 1690 return ImplicitConversionSequence::Better; 1691 else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) || 1692 (SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) || 1693 (SCS2.Second == ICK_Identity && 1694 SCS2.Third == ICK_Identity)) 1695 // SCS2 is a proper subsequence of SCS1. 1696 return ImplicitConversionSequence::Worse; 1697 1698 // -- the rank of S1 is better than the rank of S2 (by the rules 1699 // defined below), or, if not that, 1700 ImplicitConversionRank Rank1 = SCS1.getRank(); 1701 ImplicitConversionRank Rank2 = SCS2.getRank(); 1702 if (Rank1 < Rank2) 1703 return ImplicitConversionSequence::Better; 1704 else if (Rank2 < Rank1) 1705 return ImplicitConversionSequence::Worse; 1706 1707 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1708 // are indistinguishable unless one of the following rules 1709 // applies: 1710 1711 // A conversion that is not a conversion of a pointer, or 1712 // pointer to member, to bool is better than another conversion 1713 // that is such a conversion. 1714 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1715 return SCS2.isPointerConversionToBool() 1716 ? ImplicitConversionSequence::Better 1717 : ImplicitConversionSequence::Worse; 1718 1719 // C++ [over.ics.rank]p4b2: 1720 // 1721 // If class B is derived directly or indirectly from class A, 1722 // conversion of B* to A* is better than conversion of B* to 1723 // void*, and conversion of A* to void* is better than conversion 1724 // of B* to void*. 1725 bool SCS1ConvertsToVoid 1726 = SCS1.isPointerConversionToVoidPointer(Context); 1727 bool SCS2ConvertsToVoid 1728 = SCS2.isPointerConversionToVoidPointer(Context); 1729 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1730 // Exactly one of the conversion sequences is a conversion to 1731 // a void pointer; it's the worse conversion. 1732 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1733 : ImplicitConversionSequence::Worse; 1734 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1735 // Neither conversion sequence converts to a void pointer; compare 1736 // their derived-to-base conversions. 1737 if (ImplicitConversionSequence::CompareKind DerivedCK 1738 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1739 return DerivedCK; 1740 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1741 // Both conversion sequences are conversions to void 1742 // pointers. Compare the source types to determine if there's an 1743 // inheritance relationship in their sources. 1744 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1745 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1746 1747 // Adjust the types we're converting from via the array-to-pointer 1748 // conversion, if we need to. 1749 if (SCS1.First == ICK_Array_To_Pointer) 1750 FromType1 = Context.getArrayDecayedType(FromType1); 1751 if (SCS2.First == ICK_Array_To_Pointer) 1752 FromType2 = Context.getArrayDecayedType(FromType2); 1753 1754 QualType FromPointee1 1755 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1756 QualType FromPointee2 1757 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1758 1759 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1760 return ImplicitConversionSequence::Better; 1761 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1762 return ImplicitConversionSequence::Worse; 1763 1764 // Objective-C++: If one interface is more specific than the 1765 // other, it is the better one. 1766 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 1767 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 1768 if (FromIface1 && FromIface1) { 1769 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1770 return ImplicitConversionSequence::Better; 1771 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1772 return ImplicitConversionSequence::Worse; 1773 } 1774 } 1775 1776 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1777 // bullet 3). 1778 if (ImplicitConversionSequence::CompareKind QualCK 1779 = CompareQualificationConversions(SCS1, SCS2)) 1780 return QualCK; 1781 1782 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1783 // C++0x [over.ics.rank]p3b4: 1784 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 1785 // implicit object parameter of a non-static member function declared 1786 // without a ref-qualifier, and S1 binds an rvalue reference to an 1787 // rvalue and S2 binds an lvalue reference. 1788 // FIXME: We don't know if we're dealing with the implicit object parameter, 1789 // or if the member function in this case has a ref qualifier. 1790 // (Of course, we don't have ref qualifiers yet.) 1791 if (SCS1.RRefBinding != SCS2.RRefBinding) 1792 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 1793 : ImplicitConversionSequence::Worse; 1794 1795 // C++ [over.ics.rank]p3b4: 1796 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1797 // which the references refer are the same type except for 1798 // top-level cv-qualifiers, and the type to which the reference 1799 // initialized by S2 refers is more cv-qualified than the type 1800 // to which the reference initialized by S1 refers. 1801 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1802 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1803 T1 = Context.getCanonicalType(T1); 1804 T2 = Context.getCanonicalType(T2); 1805 Qualifiers T1Quals, T2Quals; 1806 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1807 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1808 if (UnqualT1 == UnqualT2) { 1809 // If the type is an array type, promote the element qualifiers to the type 1810 // for comparison. 1811 if (isa<ArrayType>(T1) && T1Quals) 1812 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 1813 if (isa<ArrayType>(T2) && T2Quals) 1814 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 1815 if (T2.isMoreQualifiedThan(T1)) 1816 return ImplicitConversionSequence::Better; 1817 else if (T1.isMoreQualifiedThan(T2)) 1818 return ImplicitConversionSequence::Worse; 1819 } 1820 } 1821 1822 return ImplicitConversionSequence::Indistinguishable; 1823} 1824 1825/// CompareQualificationConversions - Compares two standard conversion 1826/// sequences to determine whether they can be ranked based on their 1827/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1828ImplicitConversionSequence::CompareKind 1829Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1830 const StandardConversionSequence& SCS2) { 1831 // C++ 13.3.3.2p3: 1832 // -- S1 and S2 differ only in their qualification conversion and 1833 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1834 // cv-qualification signature of type T1 is a proper subset of 1835 // the cv-qualification signature of type T2, and S1 is not the 1836 // deprecated string literal array-to-pointer conversion (4.2). 1837 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1838 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1839 return ImplicitConversionSequence::Indistinguishable; 1840 1841 // FIXME: the example in the standard doesn't use a qualification 1842 // conversion (!) 1843 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1844 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1845 T1 = Context.getCanonicalType(T1); 1846 T2 = Context.getCanonicalType(T2); 1847 Qualifiers T1Quals, T2Quals; 1848 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals); 1849 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals); 1850 1851 // If the types are the same, we won't learn anything by unwrapped 1852 // them. 1853 if (UnqualT1 == UnqualT2) 1854 return ImplicitConversionSequence::Indistinguishable; 1855 1856 // If the type is an array type, promote the element qualifiers to the type 1857 // for comparison. 1858 if (isa<ArrayType>(T1) && T1Quals) 1859 T1 = Context.getQualifiedType(UnqualT1, T1Quals); 1860 if (isa<ArrayType>(T2) && T2Quals) 1861 T2 = Context.getQualifiedType(UnqualT2, T2Quals); 1862 1863 ImplicitConversionSequence::CompareKind Result 1864 = ImplicitConversionSequence::Indistinguishable; 1865 while (UnwrapSimilarPointerTypes(T1, T2)) { 1866 // Within each iteration of the loop, we check the qualifiers to 1867 // determine if this still looks like a qualification 1868 // conversion. Then, if all is well, we unwrap one more level of 1869 // pointers or pointers-to-members and do it all again 1870 // until there are no more pointers or pointers-to-members left 1871 // to unwrap. This essentially mimics what 1872 // IsQualificationConversion does, but here we're checking for a 1873 // strict subset of qualifiers. 1874 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1875 // The qualifiers are the same, so this doesn't tell us anything 1876 // about how the sequences rank. 1877 ; 1878 else if (T2.isMoreQualifiedThan(T1)) { 1879 // T1 has fewer qualifiers, so it could be the better sequence. 1880 if (Result == ImplicitConversionSequence::Worse) 1881 // Neither has qualifiers that are a subset of the other's 1882 // qualifiers. 1883 return ImplicitConversionSequence::Indistinguishable; 1884 1885 Result = ImplicitConversionSequence::Better; 1886 } else if (T1.isMoreQualifiedThan(T2)) { 1887 // T2 has fewer qualifiers, so it could be the better sequence. 1888 if (Result == ImplicitConversionSequence::Better) 1889 // Neither has qualifiers that are a subset of the other's 1890 // qualifiers. 1891 return ImplicitConversionSequence::Indistinguishable; 1892 1893 Result = ImplicitConversionSequence::Worse; 1894 } else { 1895 // Qualifiers are disjoint. 1896 return ImplicitConversionSequence::Indistinguishable; 1897 } 1898 1899 // If the types after this point are equivalent, we're done. 1900 if (Context.hasSameUnqualifiedType(T1, T2)) 1901 break; 1902 } 1903 1904 // Check that the winning standard conversion sequence isn't using 1905 // the deprecated string literal array to pointer conversion. 1906 switch (Result) { 1907 case ImplicitConversionSequence::Better: 1908 if (SCS1.Deprecated) 1909 Result = ImplicitConversionSequence::Indistinguishable; 1910 break; 1911 1912 case ImplicitConversionSequence::Indistinguishable: 1913 break; 1914 1915 case ImplicitConversionSequence::Worse: 1916 if (SCS2.Deprecated) 1917 Result = ImplicitConversionSequence::Indistinguishable; 1918 break; 1919 } 1920 1921 return Result; 1922} 1923 1924/// CompareDerivedToBaseConversions - Compares two standard conversion 1925/// sequences to determine whether they can be ranked based on their 1926/// various kinds of derived-to-base conversions (C++ 1927/// [over.ics.rank]p4b3). As part of these checks, we also look at 1928/// conversions between Objective-C interface types. 1929ImplicitConversionSequence::CompareKind 1930Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 1931 const StandardConversionSequence& SCS2) { 1932 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1933 QualType ToType1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1934 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1935 QualType ToType2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1936 1937 // Adjust the types we're converting from via the array-to-pointer 1938 // conversion, if we need to. 1939 if (SCS1.First == ICK_Array_To_Pointer) 1940 FromType1 = Context.getArrayDecayedType(FromType1); 1941 if (SCS2.First == ICK_Array_To_Pointer) 1942 FromType2 = Context.getArrayDecayedType(FromType2); 1943 1944 // Canonicalize all of the types. 1945 FromType1 = Context.getCanonicalType(FromType1); 1946 ToType1 = Context.getCanonicalType(ToType1); 1947 FromType2 = Context.getCanonicalType(FromType2); 1948 ToType2 = Context.getCanonicalType(ToType2); 1949 1950 // C++ [over.ics.rank]p4b3: 1951 // 1952 // If class B is derived directly or indirectly from class A and 1953 // class C is derived directly or indirectly from B, 1954 // 1955 // For Objective-C, we let A, B, and C also be Objective-C 1956 // interfaces. 1957 1958 // Compare based on pointer conversions. 1959 if (SCS1.Second == ICK_Pointer_Conversion && 1960 SCS2.Second == ICK_Pointer_Conversion && 1961 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 1962 FromType1->isPointerType() && FromType2->isPointerType() && 1963 ToType1->isPointerType() && ToType2->isPointerType()) { 1964 QualType FromPointee1 1965 = FromType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1966 QualType ToPointee1 1967 = ToType1->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1968 QualType FromPointee2 1969 = FromType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1970 QualType ToPointee2 1971 = ToType2->getAs<PointerType>()->getPointeeType().getUnqualifiedType(); 1972 1973 const ObjCInterfaceType* FromIface1 = FromPointee1->getAs<ObjCInterfaceType>(); 1974 const ObjCInterfaceType* FromIface2 = FromPointee2->getAs<ObjCInterfaceType>(); 1975 const ObjCInterfaceType* ToIface1 = ToPointee1->getAs<ObjCInterfaceType>(); 1976 const ObjCInterfaceType* ToIface2 = ToPointee2->getAs<ObjCInterfaceType>(); 1977 1978 // -- conversion of C* to B* is better than conversion of C* to A*, 1979 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 1980 if (IsDerivedFrom(ToPointee1, ToPointee2)) 1981 return ImplicitConversionSequence::Better; 1982 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 1983 return ImplicitConversionSequence::Worse; 1984 1985 if (ToIface1 && ToIface2) { 1986 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 1987 return ImplicitConversionSequence::Better; 1988 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 1989 return ImplicitConversionSequence::Worse; 1990 } 1991 } 1992 1993 // -- conversion of B* to A* is better than conversion of C* to A*, 1994 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 1995 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1996 return ImplicitConversionSequence::Better; 1997 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1998 return ImplicitConversionSequence::Worse; 1999 2000 if (FromIface1 && FromIface2) { 2001 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 2002 return ImplicitConversionSequence::Better; 2003 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 2004 return ImplicitConversionSequence::Worse; 2005 } 2006 } 2007 } 2008 2009 // Compare based on reference bindings. 2010 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding && 2011 SCS1.Second == ICK_Derived_To_Base) { 2012 // -- binding of an expression of type C to a reference of type 2013 // B& is better than binding an expression of type C to a 2014 // reference of type A&, 2015 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2016 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2017 if (IsDerivedFrom(ToType1, ToType2)) 2018 return ImplicitConversionSequence::Better; 2019 else if (IsDerivedFrom(ToType2, ToType1)) 2020 return ImplicitConversionSequence::Worse; 2021 } 2022 2023 // -- binding of an expression of type B to a reference of type 2024 // A& is better than binding an expression of type C to a 2025 // reference of type A&, 2026 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2027 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2028 if (IsDerivedFrom(FromType2, FromType1)) 2029 return ImplicitConversionSequence::Better; 2030 else if (IsDerivedFrom(FromType1, FromType2)) 2031 return ImplicitConversionSequence::Worse; 2032 } 2033 } 2034 2035 // Ranking of member-pointer types. 2036 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member && 2037 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() && 2038 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) { 2039 const MemberPointerType * FromMemPointer1 = 2040 FromType1->getAs<MemberPointerType>(); 2041 const MemberPointerType * ToMemPointer1 = 2042 ToType1->getAs<MemberPointerType>(); 2043 const MemberPointerType * FromMemPointer2 = 2044 FromType2->getAs<MemberPointerType>(); 2045 const MemberPointerType * ToMemPointer2 = 2046 ToType2->getAs<MemberPointerType>(); 2047 const Type *FromPointeeType1 = FromMemPointer1->getClass(); 2048 const Type *ToPointeeType1 = ToMemPointer1->getClass(); 2049 const Type *FromPointeeType2 = FromMemPointer2->getClass(); 2050 const Type *ToPointeeType2 = ToMemPointer2->getClass(); 2051 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType(); 2052 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType(); 2053 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType(); 2054 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType(); 2055 // conversion of A::* to B::* is better than conversion of A::* to C::*, 2056 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 2057 if (IsDerivedFrom(ToPointee1, ToPointee2)) 2058 return ImplicitConversionSequence::Worse; 2059 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 2060 return ImplicitConversionSequence::Better; 2061 } 2062 // conversion of B::* to C::* is better than conversion of A::* to C::* 2063 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) { 2064 if (IsDerivedFrom(FromPointee1, FromPointee2)) 2065 return ImplicitConversionSequence::Better; 2066 else if (IsDerivedFrom(FromPointee2, FromPointee1)) 2067 return ImplicitConversionSequence::Worse; 2068 } 2069 } 2070 2071 if (SCS1.CopyConstructor && SCS2.CopyConstructor && 2072 SCS1.Second == ICK_Derived_To_Base) { 2073 // -- conversion of C to B is better than conversion of C to A, 2074 if (Context.hasSameUnqualifiedType(FromType1, FromType2) && 2075 !Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2076 if (IsDerivedFrom(ToType1, ToType2)) 2077 return ImplicitConversionSequence::Better; 2078 else if (IsDerivedFrom(ToType2, ToType1)) 2079 return ImplicitConversionSequence::Worse; 2080 } 2081 2082 // -- conversion of B to A is better than conversion of C to A. 2083 if (!Context.hasSameUnqualifiedType(FromType1, FromType2) && 2084 Context.hasSameUnqualifiedType(ToType1, ToType2)) { 2085 if (IsDerivedFrom(FromType2, FromType1)) 2086 return ImplicitConversionSequence::Better; 2087 else if (IsDerivedFrom(FromType1, FromType2)) 2088 return ImplicitConversionSequence::Worse; 2089 } 2090 } 2091 2092 return ImplicitConversionSequence::Indistinguishable; 2093} 2094 2095/// TryCopyInitialization - Try to copy-initialize a value of type 2096/// ToType from the expression From. Return the implicit conversion 2097/// sequence required to pass this argument, which may be a bad 2098/// conversion sequence (meaning that the argument cannot be passed to 2099/// a parameter of this type). If @p SuppressUserConversions, then we 2100/// do not permit any user-defined conversion sequences. If @p ForceRValue, 2101/// then we treat @p From as an rvalue, even if it is an lvalue. 2102ImplicitConversionSequence 2103Sema::TryCopyInitialization(Expr *From, QualType ToType, 2104 bool SuppressUserConversions, bool ForceRValue, 2105 bool InOverloadResolution) { 2106 if (ToType->isReferenceType()) { 2107 ImplicitConversionSequence ICS; 2108 CheckReferenceInit(From, ToType, 2109 /*FIXME:*/From->getLocStart(), 2110 SuppressUserConversions, 2111 /*AllowExplicit=*/false, 2112 ForceRValue, 2113 &ICS); 2114 return ICS; 2115 } else { 2116 return TryImplicitConversion(From, ToType, 2117 SuppressUserConversions, 2118 /*AllowExplicit=*/false, 2119 ForceRValue, 2120 InOverloadResolution); 2121 } 2122} 2123 2124/// PerformCopyInitialization - Copy-initialize an object of type @p ToType with 2125/// the expression @p From. Returns true (and emits a diagnostic) if there was 2126/// an error, returns false if the initialization succeeded. Elidable should 2127/// be true when the copy may be elided (C++ 12.8p15). Overload resolution works 2128/// differently in C++0x for this case. 2129bool Sema::PerformCopyInitialization(Expr *&From, QualType ToType, 2130 AssignmentAction Action, bool Elidable) { 2131 if (!getLangOptions().CPlusPlus) { 2132 // In C, argument passing is the same as performing an assignment. 2133 QualType FromType = From->getType(); 2134 2135 AssignConvertType ConvTy = 2136 CheckSingleAssignmentConstraints(ToType, From); 2137 if (ConvTy != Compatible && 2138 CheckTransparentUnionArgumentConstraints(ToType, From) == Compatible) 2139 ConvTy = Compatible; 2140 2141 return DiagnoseAssignmentResult(ConvTy, From->getLocStart(), ToType, 2142 FromType, From, Action); 2143 } 2144 2145 if (ToType->isReferenceType()) 2146 return CheckReferenceInit(From, ToType, 2147 /*FIXME:*/From->getLocStart(), 2148 /*SuppressUserConversions=*/false, 2149 /*AllowExplicit=*/false, 2150 /*ForceRValue=*/false); 2151 2152 if (!PerformImplicitConversion(From, ToType, Action, 2153 /*AllowExplicit=*/false, Elidable)) 2154 return false; 2155 if (!DiagnoseMultipleUserDefinedConversion(From, ToType)) 2156 return Diag(From->getSourceRange().getBegin(), 2157 diag::err_typecheck_convert_incompatible) 2158 << ToType << From->getType() << Action << From->getSourceRange(); 2159 return true; 2160} 2161 2162/// TryObjectArgumentInitialization - Try to initialize the object 2163/// parameter of the given member function (@c Method) from the 2164/// expression @p From. 2165ImplicitConversionSequence 2166Sema::TryObjectArgumentInitialization(QualType FromType, 2167 CXXMethodDecl *Method, 2168 CXXRecordDecl *ActingContext) { 2169 QualType ClassType = Context.getTypeDeclType(ActingContext); 2170 // [class.dtor]p2: A destructor can be invoked for a const, volatile or 2171 // const volatile object. 2172 unsigned Quals = isa<CXXDestructorDecl>(Method) ? 2173 Qualifiers::Const | Qualifiers::Volatile : Method->getTypeQualifiers(); 2174 QualType ImplicitParamType = Context.getCVRQualifiedType(ClassType, Quals); 2175 2176 // Set up the conversion sequence as a "bad" conversion, to allow us 2177 // to exit early. 2178 ImplicitConversionSequence ICS; 2179 ICS.Standard.setAsIdentityConversion(); 2180 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 2181 2182 // We need to have an object of class type. 2183 if (const PointerType *PT = FromType->getAs<PointerType>()) 2184 FromType = PT->getPointeeType(); 2185 2186 assert(FromType->isRecordType()); 2187 2188 // The implicit object parameter is has the type "reference to cv X", 2189 // where X is the class of which the function is a member 2190 // (C++ [over.match.funcs]p4). However, when finding an implicit 2191 // conversion sequence for the argument, we are not allowed to 2192 // create temporaries or perform user-defined conversions 2193 // (C++ [over.match.funcs]p5). We perform a simplified version of 2194 // reference binding here, that allows class rvalues to bind to 2195 // non-constant references. 2196 2197 // First check the qualifiers. We don't care about lvalue-vs-rvalue 2198 // with the implicit object parameter (C++ [over.match.funcs]p5). 2199 QualType FromTypeCanon = Context.getCanonicalType(FromType); 2200 if (ImplicitParamType.getCVRQualifiers() 2201 != FromTypeCanon.getLocalCVRQualifiers() && 2202 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) 2203 return ICS; 2204 2205 // Check that we have either the same type or a derived type. It 2206 // affects the conversion rank. 2207 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 2208 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) 2209 ICS.Standard.Second = ICK_Identity; 2210 else if (IsDerivedFrom(FromType, ClassType)) 2211 ICS.Standard.Second = ICK_Derived_To_Base; 2212 else 2213 return ICS; 2214 2215 // Success. Mark this as a reference binding. 2216 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 2217 ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr(); 2218 ICS.Standard.ToTypePtr = ImplicitParamType.getAsOpaquePtr(); 2219 ICS.Standard.ReferenceBinding = true; 2220 ICS.Standard.DirectBinding = true; 2221 ICS.Standard.RRefBinding = false; 2222 return ICS; 2223} 2224 2225/// PerformObjectArgumentInitialization - Perform initialization of 2226/// the implicit object parameter for the given Method with the given 2227/// expression. 2228bool 2229Sema::PerformObjectArgumentInitialization(Expr *&From, CXXMethodDecl *Method) { 2230 QualType FromRecordType, DestType; 2231 QualType ImplicitParamRecordType = 2232 Method->getThisType(Context)->getAs<PointerType>()->getPointeeType(); 2233 2234 if (const PointerType *PT = From->getType()->getAs<PointerType>()) { 2235 FromRecordType = PT->getPointeeType(); 2236 DestType = Method->getThisType(Context); 2237 } else { 2238 FromRecordType = From->getType(); 2239 DestType = ImplicitParamRecordType; 2240 } 2241 2242 // Note that we always use the true parent context when performing 2243 // the actual argument initialization. 2244 ImplicitConversionSequence ICS 2245 = TryObjectArgumentInitialization(From->getType(), Method, 2246 Method->getParent()); 2247 if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) 2248 return Diag(From->getSourceRange().getBegin(), 2249 diag::err_implicit_object_parameter_init) 2250 << ImplicitParamRecordType << FromRecordType << From->getSourceRange(); 2251 2252 if (ICS.Standard.Second == ICK_Derived_To_Base && 2253 CheckDerivedToBaseConversion(FromRecordType, 2254 ImplicitParamRecordType, 2255 From->getSourceRange().getBegin(), 2256 From->getSourceRange())) 2257 return true; 2258 2259 ImpCastExprToType(From, DestType, CastExpr::CK_DerivedToBase, 2260 /*isLvalue=*/true); 2261 return false; 2262} 2263 2264/// TryContextuallyConvertToBool - Attempt to contextually convert the 2265/// expression From to bool (C++0x [conv]p3). 2266ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 2267 return TryImplicitConversion(From, Context.BoolTy, 2268 // FIXME: Are these flags correct? 2269 /*SuppressUserConversions=*/false, 2270 /*AllowExplicit=*/true, 2271 /*ForceRValue=*/false, 2272 /*InOverloadResolution=*/false); 2273} 2274 2275/// PerformContextuallyConvertToBool - Perform a contextual conversion 2276/// of the expression From to bool (C++0x [conv]p3). 2277bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 2278 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 2279 if (!PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting)) 2280 return false; 2281 2282 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy)) 2283 return Diag(From->getSourceRange().getBegin(), 2284 diag::err_typecheck_bool_condition) 2285 << From->getType() << From->getSourceRange(); 2286 return true; 2287} 2288 2289/// AddOverloadCandidate - Adds the given function to the set of 2290/// candidate functions, using the given function call arguments. If 2291/// @p SuppressUserConversions, then don't allow user-defined 2292/// conversions via constructors or conversion operators. 2293/// If @p ForceRValue, treat all arguments as rvalues. This is a slightly 2294/// hacky way to implement the overloading rules for elidable copy 2295/// initialization in C++0x (C++0x 12.8p15). 2296/// 2297/// \para PartialOverloading true if we are performing "partial" overloading 2298/// based on an incomplete set of function arguments. This feature is used by 2299/// code completion. 2300void 2301Sema::AddOverloadCandidate(FunctionDecl *Function, 2302 Expr **Args, unsigned NumArgs, 2303 OverloadCandidateSet& CandidateSet, 2304 bool SuppressUserConversions, 2305 bool ForceRValue, 2306 bool PartialOverloading) { 2307 const FunctionProtoType* Proto 2308 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>()); 2309 assert(Proto && "Functions without a prototype cannot be overloaded"); 2310 assert(!Function->getDescribedFunctionTemplate() && 2311 "Use AddTemplateOverloadCandidate for function templates"); 2312 2313 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2314 if (!isa<CXXConstructorDecl>(Method)) { 2315 // If we get here, it's because we're calling a member function 2316 // that is named without a member access expression (e.g., 2317 // "this->f") that was either written explicitly or created 2318 // implicitly. This can happen with a qualified call to a member 2319 // function, e.g., X::f(). We use an empty type for the implied 2320 // object argument (C++ [over.call.func]p3), and the acting context 2321 // is irrelevant. 2322 AddMethodCandidate(Method, Method->getParent(), 2323 QualType(), Args, NumArgs, CandidateSet, 2324 SuppressUserConversions, ForceRValue); 2325 return; 2326 } 2327 // We treat a constructor like a non-member function, since its object 2328 // argument doesn't participate in overload resolution. 2329 } 2330 2331 if (!CandidateSet.isNewCandidate(Function)) 2332 return; 2333 2334 // Overload resolution is always an unevaluated context. 2335 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2336 2337 if (CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function)){ 2338 // C++ [class.copy]p3: 2339 // A member function template is never instantiated to perform the copy 2340 // of a class object to an object of its class type. 2341 QualType ClassType = Context.getTypeDeclType(Constructor->getParent()); 2342 if (NumArgs == 1 && 2343 Constructor->isCopyConstructorLikeSpecialization() && 2344 Context.hasSameUnqualifiedType(ClassType, Args[0]->getType())) 2345 return; 2346 } 2347 2348 // Add this candidate 2349 CandidateSet.push_back(OverloadCandidate()); 2350 OverloadCandidate& Candidate = CandidateSet.back(); 2351 Candidate.Function = Function; 2352 Candidate.Viable = true; 2353 Candidate.IsSurrogate = false; 2354 Candidate.IgnoreObjectArgument = false; 2355 2356 unsigned NumArgsInProto = Proto->getNumArgs(); 2357 2358 // (C++ 13.3.2p2): A candidate function having fewer than m 2359 // parameters is viable only if it has an ellipsis in its parameter 2360 // list (8.3.5). 2361 if ((NumArgs + (PartialOverloading && NumArgs)) > NumArgsInProto && 2362 !Proto->isVariadic()) { 2363 Candidate.Viable = false; 2364 return; 2365 } 2366 2367 // (C++ 13.3.2p2): A candidate function having more than m parameters 2368 // is viable only if the (m+1)st parameter has a default argument 2369 // (8.3.6). For the purposes of overload resolution, the 2370 // parameter list is truncated on the right, so that there are 2371 // exactly m parameters. 2372 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2373 if (NumArgs < MinRequiredArgs && !PartialOverloading) { 2374 // Not enough arguments. 2375 Candidate.Viable = false; 2376 return; 2377 } 2378 2379 // Determine the implicit conversion sequences for each of the 2380 // arguments. 2381 Candidate.Conversions.resize(NumArgs); 2382 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2383 if (ArgIdx < NumArgsInProto) { 2384 // (C++ 13.3.2p3): for F to be a viable function, there shall 2385 // exist for each argument an implicit conversion sequence 2386 // (13.3.3.1) that converts that argument to the corresponding 2387 // parameter of F. 2388 QualType ParamType = Proto->getArgType(ArgIdx); 2389 Candidate.Conversions[ArgIdx] 2390 = TryCopyInitialization(Args[ArgIdx], ParamType, 2391 SuppressUserConversions, ForceRValue, 2392 /*InOverloadResolution=*/true); 2393 if (Candidate.Conversions[ArgIdx].ConversionKind 2394 == ImplicitConversionSequence::BadConversion) { 2395 // 13.3.3.1-p10 If several different sequences of conversions exist that 2396 // each convert the argument to the parameter type, the implicit conversion 2397 // sequence associated with the parameter is defined to be the unique conversion 2398 // sequence designated the ambiguous conversion sequence. For the purpose of 2399 // ranking implicit conversion sequences as described in 13.3.3.2, the ambiguous 2400 // conversion sequence is treated as a user-defined sequence that is 2401 // indistinguishable from any other user-defined conversion sequence 2402 if (!Candidate.Conversions[ArgIdx].ConversionFunctionSet.empty()) { 2403 Candidate.Conversions[ArgIdx].ConversionKind = 2404 ImplicitConversionSequence::UserDefinedConversion; 2405 // Set the conversion function to one of them. As due to ambiguity, 2406 // they carry the same weight and is needed for overload resolution 2407 // later. 2408 Candidate.Conversions[ArgIdx].UserDefined.ConversionFunction = 2409 Candidate.Conversions[ArgIdx].ConversionFunctionSet[0]; 2410 } 2411 else { 2412 Candidate.Viable = false; 2413 break; 2414 } 2415 } 2416 } else { 2417 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2418 // argument for which there is no corresponding parameter is 2419 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2420 Candidate.Conversions[ArgIdx].ConversionKind 2421 = ImplicitConversionSequence::EllipsisConversion; 2422 } 2423 } 2424} 2425 2426/// \brief Add all of the function declarations in the given function set to 2427/// the overload canddiate set. 2428void Sema::AddFunctionCandidates(const FunctionSet &Functions, 2429 Expr **Args, unsigned NumArgs, 2430 OverloadCandidateSet& CandidateSet, 2431 bool SuppressUserConversions) { 2432 for (FunctionSet::const_iterator F = Functions.begin(), 2433 FEnd = Functions.end(); 2434 F != FEnd; ++F) { 2435 // FIXME: using declarations 2436 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*F)) { 2437 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) 2438 AddMethodCandidate(cast<CXXMethodDecl>(FD), 2439 cast<CXXMethodDecl>(FD)->getParent(), 2440 Args[0]->getType(), Args + 1, NumArgs - 1, 2441 CandidateSet, SuppressUserConversions); 2442 else 2443 AddOverloadCandidate(FD, Args, NumArgs, CandidateSet, 2444 SuppressUserConversions); 2445 } else { 2446 FunctionTemplateDecl *FunTmpl = cast<FunctionTemplateDecl>(*F); 2447 if (isa<CXXMethodDecl>(FunTmpl->getTemplatedDecl()) && 2448 !cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl())->isStatic()) 2449 AddMethodTemplateCandidate(FunTmpl, 2450 cast<CXXRecordDecl>(FunTmpl->getDeclContext()), 2451 /*FIXME: explicit args */ 0, 2452 Args[0]->getType(), Args + 1, NumArgs - 1, 2453 CandidateSet, 2454 SuppressUserConversions); 2455 else 2456 AddTemplateOverloadCandidate(FunTmpl, 2457 /*FIXME: explicit args */ 0, 2458 Args, NumArgs, CandidateSet, 2459 SuppressUserConversions); 2460 } 2461 } 2462} 2463 2464/// AddMethodCandidate - Adds a named decl (which is some kind of 2465/// method) as a method candidate to the given overload set. 2466void Sema::AddMethodCandidate(NamedDecl *Decl, 2467 QualType ObjectType, 2468 Expr **Args, unsigned NumArgs, 2469 OverloadCandidateSet& CandidateSet, 2470 bool SuppressUserConversions, bool ForceRValue) { 2471 2472 // FIXME: use this 2473 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext()); 2474 2475 if (isa<UsingShadowDecl>(Decl)) 2476 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl(); 2477 2478 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) { 2479 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) && 2480 "Expected a member function template"); 2481 AddMethodTemplateCandidate(TD, ActingContext, /*ExplicitArgs*/ 0, 2482 ObjectType, Args, NumArgs, 2483 CandidateSet, 2484 SuppressUserConversions, 2485 ForceRValue); 2486 } else { 2487 AddMethodCandidate(cast<CXXMethodDecl>(Decl), ActingContext, 2488 ObjectType, Args, NumArgs, 2489 CandidateSet, SuppressUserConversions, ForceRValue); 2490 } 2491} 2492 2493/// AddMethodCandidate - Adds the given C++ member function to the set 2494/// of candidate functions, using the given function call arguments 2495/// and the object argument (@c Object). For example, in a call 2496/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2497/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2498/// allow user-defined conversions via constructors or conversion 2499/// operators. If @p ForceRValue, treat all arguments as rvalues. This is 2500/// a slightly hacky way to implement the overloading rules for elidable copy 2501/// initialization in C++0x (C++0x 12.8p15). 2502void 2503Sema::AddMethodCandidate(CXXMethodDecl *Method, CXXRecordDecl *ActingContext, 2504 QualType ObjectType, Expr **Args, unsigned NumArgs, 2505 OverloadCandidateSet& CandidateSet, 2506 bool SuppressUserConversions, bool ForceRValue) { 2507 const FunctionProtoType* Proto 2508 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>()); 2509 assert(Proto && "Methods without a prototype cannot be overloaded"); 2510 assert(!isa<CXXConstructorDecl>(Method) && 2511 "Use AddOverloadCandidate for constructors"); 2512 2513 if (!CandidateSet.isNewCandidate(Method)) 2514 return; 2515 2516 // Overload resolution is always an unevaluated context. 2517 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2518 2519 // Add this candidate 2520 CandidateSet.push_back(OverloadCandidate()); 2521 OverloadCandidate& Candidate = CandidateSet.back(); 2522 Candidate.Function = Method; 2523 Candidate.IsSurrogate = false; 2524 Candidate.IgnoreObjectArgument = false; 2525 2526 unsigned NumArgsInProto = Proto->getNumArgs(); 2527 2528 // (C++ 13.3.2p2): A candidate function having fewer than m 2529 // parameters is viable only if it has an ellipsis in its parameter 2530 // list (8.3.5). 2531 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2532 Candidate.Viable = false; 2533 return; 2534 } 2535 2536 // (C++ 13.3.2p2): A candidate function having more than m parameters 2537 // is viable only if the (m+1)st parameter has a default argument 2538 // (8.3.6). For the purposes of overload resolution, the 2539 // parameter list is truncated on the right, so that there are 2540 // exactly m parameters. 2541 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2542 if (NumArgs < MinRequiredArgs) { 2543 // Not enough arguments. 2544 Candidate.Viable = false; 2545 return; 2546 } 2547 2548 Candidate.Viable = true; 2549 Candidate.Conversions.resize(NumArgs + 1); 2550 2551 if (Method->isStatic() || ObjectType.isNull()) 2552 // The implicit object argument is ignored. 2553 Candidate.IgnoreObjectArgument = true; 2554 else { 2555 // Determine the implicit conversion sequence for the object 2556 // parameter. 2557 Candidate.Conversions[0] 2558 = TryObjectArgumentInitialization(ObjectType, Method, ActingContext); 2559 if (Candidate.Conversions[0].ConversionKind 2560 == ImplicitConversionSequence::BadConversion) { 2561 Candidate.Viable = false; 2562 return; 2563 } 2564 } 2565 2566 // Determine the implicit conversion sequences for each of the 2567 // arguments. 2568 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2569 if (ArgIdx < NumArgsInProto) { 2570 // (C++ 13.3.2p3): for F to be a viable function, there shall 2571 // exist for each argument an implicit conversion sequence 2572 // (13.3.3.1) that converts that argument to the corresponding 2573 // parameter of F. 2574 QualType ParamType = Proto->getArgType(ArgIdx); 2575 Candidate.Conversions[ArgIdx + 1] 2576 = TryCopyInitialization(Args[ArgIdx], ParamType, 2577 SuppressUserConversions, ForceRValue, 2578 /*InOverloadResolution=*/true); 2579 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2580 == ImplicitConversionSequence::BadConversion) { 2581 Candidate.Viable = false; 2582 break; 2583 } 2584 } else { 2585 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2586 // argument for which there is no corresponding parameter is 2587 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2588 Candidate.Conversions[ArgIdx + 1].ConversionKind 2589 = ImplicitConversionSequence::EllipsisConversion; 2590 } 2591 } 2592} 2593 2594/// \brief Add a C++ member function template as a candidate to the candidate 2595/// set, using template argument deduction to produce an appropriate member 2596/// function template specialization. 2597void 2598Sema::AddMethodTemplateCandidate(FunctionTemplateDecl *MethodTmpl, 2599 CXXRecordDecl *ActingContext, 2600 const TemplateArgumentListInfo *ExplicitTemplateArgs, 2601 QualType ObjectType, 2602 Expr **Args, unsigned NumArgs, 2603 OverloadCandidateSet& CandidateSet, 2604 bool SuppressUserConversions, 2605 bool ForceRValue) { 2606 if (!CandidateSet.isNewCandidate(MethodTmpl)) 2607 return; 2608 2609 // C++ [over.match.funcs]p7: 2610 // In each case where a candidate is a function template, candidate 2611 // function template specializations are generated using template argument 2612 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 2613 // candidate functions in the usual way.113) A given name can refer to one 2614 // or more function templates and also to a set of overloaded non-template 2615 // functions. In such a case, the candidate functions generated from each 2616 // function template are combined with the set of non-template candidate 2617 // functions. 2618 TemplateDeductionInfo Info(Context); 2619 FunctionDecl *Specialization = 0; 2620 if (TemplateDeductionResult Result 2621 = DeduceTemplateArguments(MethodTmpl, ExplicitTemplateArgs, 2622 Args, NumArgs, Specialization, Info)) { 2623 // FIXME: Record what happened with template argument deduction, so 2624 // that we can give the user a beautiful diagnostic. 2625 (void)Result; 2626 return; 2627 } 2628 2629 // Add the function template specialization produced by template argument 2630 // deduction as a candidate. 2631 assert(Specialization && "Missing member function template specialization?"); 2632 assert(isa<CXXMethodDecl>(Specialization) && 2633 "Specialization is not a member function?"); 2634 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), ActingContext, 2635 ObjectType, Args, NumArgs, 2636 CandidateSet, SuppressUserConversions, ForceRValue); 2637} 2638 2639/// \brief Add a C++ function template specialization as a candidate 2640/// in the candidate set, using template argument deduction to produce 2641/// an appropriate function template specialization. 2642void 2643Sema::AddTemplateOverloadCandidate(FunctionTemplateDecl *FunctionTemplate, 2644 const TemplateArgumentListInfo *ExplicitTemplateArgs, 2645 Expr **Args, unsigned NumArgs, 2646 OverloadCandidateSet& CandidateSet, 2647 bool SuppressUserConversions, 2648 bool ForceRValue) { 2649 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 2650 return; 2651 2652 // C++ [over.match.funcs]p7: 2653 // In each case where a candidate is a function template, candidate 2654 // function template specializations are generated using template argument 2655 // deduction (14.8.3, 14.8.2). Those candidates are then handled as 2656 // candidate functions in the usual way.113) A given name can refer to one 2657 // or more function templates and also to a set of overloaded non-template 2658 // functions. In such a case, the candidate functions generated from each 2659 // function template are combined with the set of non-template candidate 2660 // functions. 2661 TemplateDeductionInfo Info(Context); 2662 FunctionDecl *Specialization = 0; 2663 if (TemplateDeductionResult Result 2664 = DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs, 2665 Args, NumArgs, Specialization, Info)) { 2666 // FIXME: Record what happened with template argument deduction, so 2667 // that we can give the user a beautiful diagnostic. 2668 (void) Result; 2669 2670 CandidateSet.push_back(OverloadCandidate()); 2671 OverloadCandidate &Candidate = CandidateSet.back(); 2672 Candidate.Function = FunctionTemplate->getTemplatedDecl(); 2673 Candidate.Viable = false; 2674 Candidate.IsSurrogate = false; 2675 Candidate.IgnoreObjectArgument = false; 2676 return; 2677 } 2678 2679 // Add the function template specialization produced by template argument 2680 // deduction as a candidate. 2681 assert(Specialization && "Missing function template specialization?"); 2682 AddOverloadCandidate(Specialization, Args, NumArgs, CandidateSet, 2683 SuppressUserConversions, ForceRValue); 2684} 2685 2686/// AddConversionCandidate - Add a C++ conversion function as a 2687/// candidate in the candidate set (C++ [over.match.conv], 2688/// C++ [over.match.copy]). From is the expression we're converting from, 2689/// and ToType is the type that we're eventually trying to convert to 2690/// (which may or may not be the same type as the type that the 2691/// conversion function produces). 2692void 2693Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 2694 CXXRecordDecl *ActingContext, 2695 Expr *From, QualType ToType, 2696 OverloadCandidateSet& CandidateSet) { 2697 assert(!Conversion->getDescribedFunctionTemplate() && 2698 "Conversion function templates use AddTemplateConversionCandidate"); 2699 2700 if (!CandidateSet.isNewCandidate(Conversion)) 2701 return; 2702 2703 // Overload resolution is always an unevaluated context. 2704 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2705 2706 // Add this candidate 2707 CandidateSet.push_back(OverloadCandidate()); 2708 OverloadCandidate& Candidate = CandidateSet.back(); 2709 Candidate.Function = Conversion; 2710 Candidate.IsSurrogate = false; 2711 Candidate.IgnoreObjectArgument = false; 2712 Candidate.FinalConversion.setAsIdentityConversion(); 2713 Candidate.FinalConversion.FromTypePtr 2714 = Conversion->getConversionType().getAsOpaquePtr(); 2715 Candidate.FinalConversion.ToTypePtr = ToType.getAsOpaquePtr(); 2716 2717 // Determine the implicit conversion sequence for the implicit 2718 // object parameter. 2719 Candidate.Viable = true; 2720 Candidate.Conversions.resize(1); 2721 Candidate.Conversions[0] 2722 = TryObjectArgumentInitialization(From->getType(), Conversion, 2723 ActingContext); 2724 // Conversion functions to a different type in the base class is visible in 2725 // the derived class. So, a derived to base conversion should not participate 2726 // in overload resolution. 2727 if (Candidate.Conversions[0].Standard.Second == ICK_Derived_To_Base) 2728 Candidate.Conversions[0].Standard.Second = ICK_Identity; 2729 if (Candidate.Conversions[0].ConversionKind 2730 == ImplicitConversionSequence::BadConversion) { 2731 Candidate.Viable = false; 2732 return; 2733 } 2734 2735 // We won't go through a user-define type conversion function to convert a 2736 // derived to base as such conversions are given Conversion Rank. They only 2737 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user] 2738 QualType FromCanon 2739 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 2740 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 2741 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 2742 Candidate.Viable = false; 2743 return; 2744 } 2745 2746 2747 // To determine what the conversion from the result of calling the 2748 // conversion function to the type we're eventually trying to 2749 // convert to (ToType), we need to synthesize a call to the 2750 // conversion function and attempt copy initialization from it. This 2751 // makes sure that we get the right semantics with respect to 2752 // lvalues/rvalues and the type. Fortunately, we can allocate this 2753 // call on the stack and we don't need its arguments to be 2754 // well-formed. 2755 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 2756 From->getLocStart()); 2757 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 2758 CastExpr::CK_FunctionToPointerDecay, 2759 &ConversionRef, false); 2760 2761 // Note that it is safe to allocate CallExpr on the stack here because 2762 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 2763 // allocator). 2764 CallExpr Call(Context, &ConversionFn, 0, 0, 2765 Conversion->getConversionType().getNonReferenceType(), 2766 From->getLocStart()); 2767 ImplicitConversionSequence ICS = 2768 TryCopyInitialization(&Call, ToType, 2769 /*SuppressUserConversions=*/true, 2770 /*ForceRValue=*/false, 2771 /*InOverloadResolution=*/false); 2772 2773 switch (ICS.ConversionKind) { 2774 case ImplicitConversionSequence::StandardConversion: 2775 Candidate.FinalConversion = ICS.Standard; 2776 break; 2777 2778 case ImplicitConversionSequence::BadConversion: 2779 Candidate.Viable = false; 2780 break; 2781 2782 default: 2783 assert(false && 2784 "Can only end up with a standard conversion sequence or failure"); 2785 } 2786} 2787 2788/// \brief Adds a conversion function template specialization 2789/// candidate to the overload set, using template argument deduction 2790/// to deduce the template arguments of the conversion function 2791/// template from the type that we are converting to (C++ 2792/// [temp.deduct.conv]). 2793void 2794Sema::AddTemplateConversionCandidate(FunctionTemplateDecl *FunctionTemplate, 2795 CXXRecordDecl *ActingDC, 2796 Expr *From, QualType ToType, 2797 OverloadCandidateSet &CandidateSet) { 2798 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) && 2799 "Only conversion function templates permitted here"); 2800 2801 if (!CandidateSet.isNewCandidate(FunctionTemplate)) 2802 return; 2803 2804 TemplateDeductionInfo Info(Context); 2805 CXXConversionDecl *Specialization = 0; 2806 if (TemplateDeductionResult Result 2807 = DeduceTemplateArguments(FunctionTemplate, ToType, 2808 Specialization, Info)) { 2809 // FIXME: Record what happened with template argument deduction, so 2810 // that we can give the user a beautiful diagnostic. 2811 (void)Result; 2812 return; 2813 } 2814 2815 // Add the conversion function template specialization produced by 2816 // template argument deduction as a candidate. 2817 assert(Specialization && "Missing function template specialization?"); 2818 AddConversionCandidate(Specialization, ActingDC, From, ToType, CandidateSet); 2819} 2820 2821/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 2822/// converts the given @c Object to a function pointer via the 2823/// conversion function @c Conversion, and then attempts to call it 2824/// with the given arguments (C++ [over.call.object]p2-4). Proto is 2825/// the type of function that we'll eventually be calling. 2826void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 2827 CXXRecordDecl *ActingContext, 2828 const FunctionProtoType *Proto, 2829 QualType ObjectType, 2830 Expr **Args, unsigned NumArgs, 2831 OverloadCandidateSet& CandidateSet) { 2832 if (!CandidateSet.isNewCandidate(Conversion)) 2833 return; 2834 2835 // Overload resolution is always an unevaluated context. 2836 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 2837 2838 CandidateSet.push_back(OverloadCandidate()); 2839 OverloadCandidate& Candidate = CandidateSet.back(); 2840 Candidate.Function = 0; 2841 Candidate.Surrogate = Conversion; 2842 Candidate.Viable = true; 2843 Candidate.IsSurrogate = true; 2844 Candidate.IgnoreObjectArgument = false; 2845 Candidate.Conversions.resize(NumArgs + 1); 2846 2847 // Determine the implicit conversion sequence for the implicit 2848 // object parameter. 2849 ImplicitConversionSequence ObjectInit 2850 = TryObjectArgumentInitialization(ObjectType, Conversion, ActingContext); 2851 if (ObjectInit.ConversionKind == ImplicitConversionSequence::BadConversion) { 2852 Candidate.Viable = false; 2853 return; 2854 } 2855 2856 // The first conversion is actually a user-defined conversion whose 2857 // first conversion is ObjectInit's standard conversion (which is 2858 // effectively a reference binding). Record it as such. 2859 Candidate.Conversions[0].ConversionKind 2860 = ImplicitConversionSequence::UserDefinedConversion; 2861 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 2862 Candidate.Conversions[0].UserDefined.EllipsisConversion = false; 2863 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 2864 Candidate.Conversions[0].UserDefined.After 2865 = Candidate.Conversions[0].UserDefined.Before; 2866 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 2867 2868 // Find the 2869 unsigned NumArgsInProto = Proto->getNumArgs(); 2870 2871 // (C++ 13.3.2p2): A candidate function having fewer than m 2872 // parameters is viable only if it has an ellipsis in its parameter 2873 // list (8.3.5). 2874 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2875 Candidate.Viable = false; 2876 return; 2877 } 2878 2879 // Function types don't have any default arguments, so just check if 2880 // we have enough arguments. 2881 if (NumArgs < NumArgsInProto) { 2882 // Not enough arguments. 2883 Candidate.Viable = false; 2884 return; 2885 } 2886 2887 // Determine the implicit conversion sequences for each of the 2888 // arguments. 2889 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2890 if (ArgIdx < NumArgsInProto) { 2891 // (C++ 13.3.2p3): for F to be a viable function, there shall 2892 // exist for each argument an implicit conversion sequence 2893 // (13.3.3.1) that converts that argument to the corresponding 2894 // parameter of F. 2895 QualType ParamType = Proto->getArgType(ArgIdx); 2896 Candidate.Conversions[ArgIdx + 1] 2897 = TryCopyInitialization(Args[ArgIdx], ParamType, 2898 /*SuppressUserConversions=*/false, 2899 /*ForceRValue=*/false, 2900 /*InOverloadResolution=*/false); 2901 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2902 == ImplicitConversionSequence::BadConversion) { 2903 Candidate.Viable = false; 2904 break; 2905 } 2906 } else { 2907 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2908 // argument for which there is no corresponding parameter is 2909 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2910 Candidate.Conversions[ArgIdx + 1].ConversionKind 2911 = ImplicitConversionSequence::EllipsisConversion; 2912 } 2913 } 2914} 2915 2916// FIXME: This will eventually be removed, once we've migrated all of the 2917// operator overloading logic over to the scheme used by binary operators, which 2918// works for template instantiation. 2919void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 2920 SourceLocation OpLoc, 2921 Expr **Args, unsigned NumArgs, 2922 OverloadCandidateSet& CandidateSet, 2923 SourceRange OpRange) { 2924 FunctionSet Functions; 2925 2926 QualType T1 = Args[0]->getType(); 2927 QualType T2; 2928 if (NumArgs > 1) 2929 T2 = Args[1]->getType(); 2930 2931 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2932 if (S) 2933 LookupOverloadedOperatorName(Op, S, T1, T2, Functions); 2934 ArgumentDependentLookup(OpName, /*Operator*/true, Args, NumArgs, Functions); 2935 AddFunctionCandidates(Functions, Args, NumArgs, CandidateSet); 2936 AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange); 2937 AddBuiltinOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet); 2938} 2939 2940/// \brief Add overload candidates for overloaded operators that are 2941/// member functions. 2942/// 2943/// Add the overloaded operator candidates that are member functions 2944/// for the operator Op that was used in an operator expression such 2945/// as "x Op y". , Args/NumArgs provides the operator arguments, and 2946/// CandidateSet will store the added overload candidates. (C++ 2947/// [over.match.oper]). 2948void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 2949 SourceLocation OpLoc, 2950 Expr **Args, unsigned NumArgs, 2951 OverloadCandidateSet& CandidateSet, 2952 SourceRange OpRange) { 2953 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2954 2955 // C++ [over.match.oper]p3: 2956 // For a unary operator @ with an operand of a type whose 2957 // cv-unqualified version is T1, and for a binary operator @ with 2958 // a left operand of a type whose cv-unqualified version is T1 and 2959 // a right operand of a type whose cv-unqualified version is T2, 2960 // three sets of candidate functions, designated member 2961 // candidates, non-member candidates and built-in candidates, are 2962 // constructed as follows: 2963 QualType T1 = Args[0]->getType(); 2964 QualType T2; 2965 if (NumArgs > 1) 2966 T2 = Args[1]->getType(); 2967 2968 // -- If T1 is a class type, the set of member candidates is the 2969 // result of the qualified lookup of T1::operator@ 2970 // (13.3.1.1.1); otherwise, the set of member candidates is 2971 // empty. 2972 if (const RecordType *T1Rec = T1->getAs<RecordType>()) { 2973 // Complete the type if it can be completed. Otherwise, we're done. 2974 if (RequireCompleteType(OpLoc, T1, PDiag())) 2975 return; 2976 2977 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName); 2978 LookupQualifiedName(Operators, T1Rec->getDecl()); 2979 Operators.suppressDiagnostics(); 2980 2981 for (LookupResult::iterator Oper = Operators.begin(), 2982 OperEnd = Operators.end(); 2983 Oper != OperEnd; 2984 ++Oper) 2985 AddMethodCandidate(*Oper, Args[0]->getType(), 2986 Args + 1, NumArgs - 1, CandidateSet, 2987 /* SuppressUserConversions = */ false); 2988 } 2989} 2990 2991/// AddBuiltinCandidate - Add a candidate for a built-in 2992/// operator. ResultTy and ParamTys are the result and parameter types 2993/// of the built-in candidate, respectively. Args and NumArgs are the 2994/// arguments being passed to the candidate. IsAssignmentOperator 2995/// should be true when this built-in candidate is an assignment 2996/// operator. NumContextualBoolArguments is the number of arguments 2997/// (at the beginning of the argument list) that will be contextually 2998/// converted to bool. 2999void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 3000 Expr **Args, unsigned NumArgs, 3001 OverloadCandidateSet& CandidateSet, 3002 bool IsAssignmentOperator, 3003 unsigned NumContextualBoolArguments) { 3004 // Overload resolution is always an unevaluated context. 3005 EnterExpressionEvaluationContext Unevaluated(*this, Action::Unevaluated); 3006 3007 // Add this candidate 3008 CandidateSet.push_back(OverloadCandidate()); 3009 OverloadCandidate& Candidate = CandidateSet.back(); 3010 Candidate.Function = 0; 3011 Candidate.IsSurrogate = false; 3012 Candidate.IgnoreObjectArgument = false; 3013 Candidate.BuiltinTypes.ResultTy = ResultTy; 3014 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3015 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 3016 3017 // Determine the implicit conversion sequences for each of the 3018 // arguments. 3019 Candidate.Viable = true; 3020 Candidate.Conversions.resize(NumArgs); 3021 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 3022 // C++ [over.match.oper]p4: 3023 // For the built-in assignment operators, conversions of the 3024 // left operand are restricted as follows: 3025 // -- no temporaries are introduced to hold the left operand, and 3026 // -- no user-defined conversions are applied to the left 3027 // operand to achieve a type match with the left-most 3028 // parameter of a built-in candidate. 3029 // 3030 // We block these conversions by turning off user-defined 3031 // conversions, since that is the only way that initialization of 3032 // a reference to a non-class type can occur from something that 3033 // is not of the same type. 3034 if (ArgIdx < NumContextualBoolArguments) { 3035 assert(ParamTys[ArgIdx] == Context.BoolTy && 3036 "Contextual conversion to bool requires bool type"); 3037 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 3038 } else { 3039 Candidate.Conversions[ArgIdx] 3040 = TryCopyInitialization(Args[ArgIdx], ParamTys[ArgIdx], 3041 ArgIdx == 0 && IsAssignmentOperator, 3042 /*ForceRValue=*/false, 3043 /*InOverloadResolution=*/false); 3044 } 3045 if (Candidate.Conversions[ArgIdx].ConversionKind 3046 == ImplicitConversionSequence::BadConversion) { 3047 Candidate.Viable = false; 3048 break; 3049 } 3050 } 3051} 3052 3053/// BuiltinCandidateTypeSet - A set of types that will be used for the 3054/// candidate operator functions for built-in operators (C++ 3055/// [over.built]). The types are separated into pointer types and 3056/// enumeration types. 3057class BuiltinCandidateTypeSet { 3058 /// TypeSet - A set of types. 3059 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 3060 3061 /// PointerTypes - The set of pointer types that will be used in the 3062 /// built-in candidates. 3063 TypeSet PointerTypes; 3064 3065 /// MemberPointerTypes - The set of member pointer types that will be 3066 /// used in the built-in candidates. 3067 TypeSet MemberPointerTypes; 3068 3069 /// EnumerationTypes - The set of enumeration types that will be 3070 /// used in the built-in candidates. 3071 TypeSet EnumerationTypes; 3072 3073 /// Sema - The semantic analysis instance where we are building the 3074 /// candidate type set. 3075 Sema &SemaRef; 3076 3077 /// Context - The AST context in which we will build the type sets. 3078 ASTContext &Context; 3079 3080 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3081 const Qualifiers &VisibleQuals); 3082 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty); 3083 3084public: 3085 /// iterator - Iterates through the types that are part of the set. 3086 typedef TypeSet::iterator iterator; 3087 3088 BuiltinCandidateTypeSet(Sema &SemaRef) 3089 : SemaRef(SemaRef), Context(SemaRef.Context) { } 3090 3091 void AddTypesConvertedFrom(QualType Ty, 3092 SourceLocation Loc, 3093 bool AllowUserConversions, 3094 bool AllowExplicitConversions, 3095 const Qualifiers &VisibleTypeConversionsQuals); 3096 3097 /// pointer_begin - First pointer type found; 3098 iterator pointer_begin() { return PointerTypes.begin(); } 3099 3100 /// pointer_end - Past the last pointer type found; 3101 iterator pointer_end() { return PointerTypes.end(); } 3102 3103 /// member_pointer_begin - First member pointer type found; 3104 iterator member_pointer_begin() { return MemberPointerTypes.begin(); } 3105 3106 /// member_pointer_end - Past the last member pointer type found; 3107 iterator member_pointer_end() { return MemberPointerTypes.end(); } 3108 3109 /// enumeration_begin - First enumeration type found; 3110 iterator enumeration_begin() { return EnumerationTypes.begin(); } 3111 3112 /// enumeration_end - Past the last enumeration type found; 3113 iterator enumeration_end() { return EnumerationTypes.end(); } 3114}; 3115 3116/// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 3117/// the set of pointer types along with any more-qualified variants of 3118/// that type. For example, if @p Ty is "int const *", this routine 3119/// will add "int const *", "int const volatile *", "int const 3120/// restrict *", and "int const volatile restrict *" to the set of 3121/// pointer types. Returns true if the add of @p Ty itself succeeded, 3122/// false otherwise. 3123/// 3124/// FIXME: what to do about extended qualifiers? 3125bool 3126BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty, 3127 const Qualifiers &VisibleQuals) { 3128 3129 // Insert this type. 3130 if (!PointerTypes.insert(Ty)) 3131 return false; 3132 3133 const PointerType *PointerTy = Ty->getAs<PointerType>(); 3134 assert(PointerTy && "type was not a pointer type!"); 3135 3136 QualType PointeeTy = PointerTy->getPointeeType(); 3137 // Don't add qualified variants of arrays. For one, they're not allowed 3138 // (the qualifier would sink to the element type), and for another, the 3139 // only overload situation where it matters is subscript or pointer +- int, 3140 // and those shouldn't have qualifier variants anyway. 3141 if (PointeeTy->isArrayType()) 3142 return true; 3143 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3144 if (const ConstantArrayType *Array =Context.getAsConstantArrayType(PointeeTy)) 3145 BaseCVR = Array->getElementType().getCVRQualifiers(); 3146 bool hasVolatile = VisibleQuals.hasVolatile(); 3147 bool hasRestrict = VisibleQuals.hasRestrict(); 3148 3149 // Iterate through all strict supersets of BaseCVR. 3150 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3151 if ((CVR | BaseCVR) != CVR) continue; 3152 // Skip over Volatile/Restrict if no Volatile/Restrict found anywhere 3153 // in the types. 3154 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue; 3155 if ((CVR & Qualifiers::Restrict) && !hasRestrict) continue; 3156 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3157 PointerTypes.insert(Context.getPointerType(QPointeeTy)); 3158 } 3159 3160 return true; 3161} 3162 3163/// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty 3164/// to the set of pointer types along with any more-qualified variants of 3165/// that type. For example, if @p Ty is "int const *", this routine 3166/// will add "int const *", "int const volatile *", "int const 3167/// restrict *", and "int const volatile restrict *" to the set of 3168/// pointer types. Returns true if the add of @p Ty itself succeeded, 3169/// false otherwise. 3170/// 3171/// FIXME: what to do about extended qualifiers? 3172bool 3173BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants( 3174 QualType Ty) { 3175 // Insert this type. 3176 if (!MemberPointerTypes.insert(Ty)) 3177 return false; 3178 3179 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>(); 3180 assert(PointerTy && "type was not a member pointer type!"); 3181 3182 QualType PointeeTy = PointerTy->getPointeeType(); 3183 // Don't add qualified variants of arrays. For one, they're not allowed 3184 // (the qualifier would sink to the element type), and for another, the 3185 // only overload situation where it matters is subscript or pointer +- int, 3186 // and those shouldn't have qualifier variants anyway. 3187 if (PointeeTy->isArrayType()) 3188 return true; 3189 const Type *ClassTy = PointerTy->getClass(); 3190 3191 // Iterate through all strict supersets of the pointee type's CVR 3192 // qualifiers. 3193 unsigned BaseCVR = PointeeTy.getCVRQualifiers(); 3194 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) { 3195 if ((CVR | BaseCVR) != CVR) continue; 3196 3197 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR); 3198 MemberPointerTypes.insert(Context.getMemberPointerType(QPointeeTy, ClassTy)); 3199 } 3200 3201 return true; 3202} 3203 3204/// AddTypesConvertedFrom - Add each of the types to which the type @p 3205/// Ty can be implicit converted to the given set of @p Types. We're 3206/// primarily interested in pointer types and enumeration types. We also 3207/// take member pointer types, for the conditional operator. 3208/// AllowUserConversions is true if we should look at the conversion 3209/// functions of a class type, and AllowExplicitConversions if we 3210/// should also include the explicit conversion functions of a class 3211/// type. 3212void 3213BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 3214 SourceLocation Loc, 3215 bool AllowUserConversions, 3216 bool AllowExplicitConversions, 3217 const Qualifiers &VisibleQuals) { 3218 // Only deal with canonical types. 3219 Ty = Context.getCanonicalType(Ty); 3220 3221 // Look through reference types; they aren't part of the type of an 3222 // expression for the purposes of conversions. 3223 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>()) 3224 Ty = RefTy->getPointeeType(); 3225 3226 // We don't care about qualifiers on the type. 3227 Ty = Ty.getLocalUnqualifiedType(); 3228 3229 // If we're dealing with an array type, decay to the pointer. 3230 if (Ty->isArrayType()) 3231 Ty = SemaRef.Context.getArrayDecayedType(Ty); 3232 3233 if (const PointerType *PointerTy = Ty->getAs<PointerType>()) { 3234 QualType PointeeTy = PointerTy->getPointeeType(); 3235 3236 // Insert our type, and its more-qualified variants, into the set 3237 // of types. 3238 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals)) 3239 return; 3240 } else if (Ty->isMemberPointerType()) { 3241 // Member pointers are far easier, since the pointee can't be converted. 3242 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty)) 3243 return; 3244 } else if (Ty->isEnumeralType()) { 3245 EnumerationTypes.insert(Ty); 3246 } else if (AllowUserConversions) { 3247 if (const RecordType *TyRec = Ty->getAs<RecordType>()) { 3248 if (SemaRef.RequireCompleteType(Loc, Ty, 0)) { 3249 // No conversion functions in incomplete types. 3250 return; 3251 } 3252 3253 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3254 const UnresolvedSet *Conversions 3255 = ClassDecl->getVisibleConversionFunctions(); 3256 for (UnresolvedSet::iterator I = Conversions->begin(), 3257 E = Conversions->end(); I != E; ++I) { 3258 3259 // Skip conversion function templates; they don't tell us anything 3260 // about which builtin types we can convert to. 3261 if (isa<FunctionTemplateDecl>(*I)) 3262 continue; 3263 3264 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*I); 3265 if (AllowExplicitConversions || !Conv->isExplicit()) { 3266 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false, 3267 VisibleQuals); 3268 } 3269 } 3270 } 3271 } 3272} 3273 3274/// \brief Helper function for AddBuiltinOperatorCandidates() that adds 3275/// the volatile- and non-volatile-qualified assignment operators for the 3276/// given type to the candidate set. 3277static void AddBuiltinAssignmentOperatorCandidates(Sema &S, 3278 QualType T, 3279 Expr **Args, 3280 unsigned NumArgs, 3281 OverloadCandidateSet &CandidateSet) { 3282 QualType ParamTypes[2]; 3283 3284 // T& operator=(T&, T) 3285 ParamTypes[0] = S.Context.getLValueReferenceType(T); 3286 ParamTypes[1] = T; 3287 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3288 /*IsAssignmentOperator=*/true); 3289 3290 if (!S.Context.getCanonicalType(T).isVolatileQualified()) { 3291 // volatile T& operator=(volatile T&, T) 3292 ParamTypes[0] 3293 = S.Context.getLValueReferenceType(S.Context.getVolatileType(T)); 3294 ParamTypes[1] = T; 3295 S.AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3296 /*IsAssignmentOperator=*/true); 3297 } 3298} 3299 3300/// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers, 3301/// if any, found in visible type conversion functions found in ArgExpr's type. 3302static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) { 3303 Qualifiers VRQuals; 3304 const RecordType *TyRec; 3305 if (const MemberPointerType *RHSMPType = 3306 ArgExpr->getType()->getAs<MemberPointerType>()) 3307 TyRec = cast<RecordType>(RHSMPType->getClass()); 3308 else 3309 TyRec = ArgExpr->getType()->getAs<RecordType>(); 3310 if (!TyRec) { 3311 // Just to be safe, assume the worst case. 3312 VRQuals.addVolatile(); 3313 VRQuals.addRestrict(); 3314 return VRQuals; 3315 } 3316 3317 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 3318 const UnresolvedSet *Conversions = 3319 ClassDecl->getVisibleConversionFunctions(); 3320 3321 for (UnresolvedSet::iterator I = Conversions->begin(), 3322 E = Conversions->end(); I != E; ++I) { 3323 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(*I)) { 3324 QualType CanTy = Context.getCanonicalType(Conv->getConversionType()); 3325 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>()) 3326 CanTy = ResTypeRef->getPointeeType(); 3327 // Need to go down the pointer/mempointer chain and add qualifiers 3328 // as see them. 3329 bool done = false; 3330 while (!done) { 3331 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>()) 3332 CanTy = ResTypePtr->getPointeeType(); 3333 else if (const MemberPointerType *ResTypeMPtr = 3334 CanTy->getAs<MemberPointerType>()) 3335 CanTy = ResTypeMPtr->getPointeeType(); 3336 else 3337 done = true; 3338 if (CanTy.isVolatileQualified()) 3339 VRQuals.addVolatile(); 3340 if (CanTy.isRestrictQualified()) 3341 VRQuals.addRestrict(); 3342 if (VRQuals.hasRestrict() && VRQuals.hasVolatile()) 3343 return VRQuals; 3344 } 3345 } 3346 } 3347 return VRQuals; 3348} 3349 3350/// AddBuiltinOperatorCandidates - Add the appropriate built-in 3351/// operator overloads to the candidate set (C++ [over.built]), based 3352/// on the operator @p Op and the arguments given. For example, if the 3353/// operator is a binary '+', this routine might add "int 3354/// operator+(int, int)" to cover integer addition. 3355void 3356Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 3357 SourceLocation OpLoc, 3358 Expr **Args, unsigned NumArgs, 3359 OverloadCandidateSet& CandidateSet) { 3360 // The set of "promoted arithmetic types", which are the arithmetic 3361 // types are that preserved by promotion (C++ [over.built]p2). Note 3362 // that the first few of these types are the promoted integral 3363 // types; these types need to be first. 3364 // FIXME: What about complex? 3365 const unsigned FirstIntegralType = 0; 3366 const unsigned LastIntegralType = 13; 3367 const unsigned FirstPromotedIntegralType = 7, 3368 LastPromotedIntegralType = 13; 3369 const unsigned FirstPromotedArithmeticType = 7, 3370 LastPromotedArithmeticType = 16; 3371 const unsigned NumArithmeticTypes = 16; 3372 QualType ArithmeticTypes[NumArithmeticTypes] = { 3373 Context.BoolTy, Context.CharTy, Context.WCharTy, 3374// FIXME: Context.Char16Ty, Context.Char32Ty, 3375 Context.SignedCharTy, Context.ShortTy, 3376 Context.UnsignedCharTy, Context.UnsignedShortTy, 3377 Context.IntTy, Context.LongTy, Context.LongLongTy, 3378 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 3379 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 3380 }; 3381 assert(ArithmeticTypes[FirstPromotedIntegralType] == Context.IntTy && 3382 "Invalid first promoted integral type"); 3383 assert(ArithmeticTypes[LastPromotedIntegralType - 1] 3384 == Context.UnsignedLongLongTy && 3385 "Invalid last promoted integral type"); 3386 assert(ArithmeticTypes[FirstPromotedArithmeticType] == Context.IntTy && 3387 "Invalid first promoted arithmetic type"); 3388 assert(ArithmeticTypes[LastPromotedArithmeticType - 1] 3389 == Context.LongDoubleTy && 3390 "Invalid last promoted arithmetic type"); 3391 3392 // Find all of the types that the arguments can convert to, but only 3393 // if the operator we're looking at has built-in operator candidates 3394 // that make use of these types. 3395 Qualifiers VisibleTypeConversionsQuals; 3396 VisibleTypeConversionsQuals.addConst(); 3397 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3398 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]); 3399 3400 BuiltinCandidateTypeSet CandidateTypes(*this); 3401 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 3402 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 3403 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 3404 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 3405 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 3406 (Op == OO_Star && NumArgs == 1) || Op == OO_Conditional) { 3407 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 3408 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 3409 OpLoc, 3410 true, 3411 (Op == OO_Exclaim || 3412 Op == OO_AmpAmp || 3413 Op == OO_PipePipe), 3414 VisibleTypeConversionsQuals); 3415 } 3416 3417 bool isComparison = false; 3418 switch (Op) { 3419 case OO_None: 3420 case NUM_OVERLOADED_OPERATORS: 3421 assert(false && "Expected an overloaded operator"); 3422 break; 3423 3424 case OO_Star: // '*' is either unary or binary 3425 if (NumArgs == 1) 3426 goto UnaryStar; 3427 else 3428 goto BinaryStar; 3429 break; 3430 3431 case OO_Plus: // '+' is either unary or binary 3432 if (NumArgs == 1) 3433 goto UnaryPlus; 3434 else 3435 goto BinaryPlus; 3436 break; 3437 3438 case OO_Minus: // '-' is either unary or binary 3439 if (NumArgs == 1) 3440 goto UnaryMinus; 3441 else 3442 goto BinaryMinus; 3443 break; 3444 3445 case OO_Amp: // '&' is either unary or binary 3446 if (NumArgs == 1) 3447 goto UnaryAmp; 3448 else 3449 goto BinaryAmp; 3450 3451 case OO_PlusPlus: 3452 case OO_MinusMinus: 3453 // C++ [over.built]p3: 3454 // 3455 // For every pair (T, VQ), where T is an arithmetic type, and VQ 3456 // is either volatile or empty, there exist candidate operator 3457 // functions of the form 3458 // 3459 // VQ T& operator++(VQ T&); 3460 // T operator++(VQ T&, int); 3461 // 3462 // C++ [over.built]p4: 3463 // 3464 // For every pair (T, VQ), where T is an arithmetic type other 3465 // than bool, and VQ is either volatile or empty, there exist 3466 // candidate operator functions of the form 3467 // 3468 // VQ T& operator--(VQ T&); 3469 // T operator--(VQ T&, int); 3470 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 3471 Arith < NumArithmeticTypes; ++Arith) { 3472 QualType ArithTy = ArithmeticTypes[Arith]; 3473 QualType ParamTypes[2] 3474 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 3475 3476 // Non-volatile version. 3477 if (NumArgs == 1) 3478 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3479 else 3480 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3481 // heuristic to reduce number of builtin candidates in the set. 3482 // Add volatile version only if there are conversions to a volatile type. 3483 if (VisibleTypeConversionsQuals.hasVolatile()) { 3484 // Volatile version 3485 ParamTypes[0] 3486 = Context.getLValueReferenceType(Context.getVolatileType(ArithTy)); 3487 if (NumArgs == 1) 3488 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3489 else 3490 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 3491 } 3492 } 3493 3494 // C++ [over.built]p5: 3495 // 3496 // For every pair (T, VQ), where T is a cv-qualified or 3497 // cv-unqualified object type, and VQ is either volatile or 3498 // empty, there exist candidate operator functions of the form 3499 // 3500 // T*VQ& operator++(T*VQ&); 3501 // T*VQ& operator--(T*VQ&); 3502 // T* operator++(T*VQ&, int); 3503 // T* operator--(T*VQ&, int); 3504 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3505 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3506 // Skip pointer types that aren't pointers to object types. 3507 if (!(*Ptr)->getAs<PointerType>()->getPointeeType()->isObjectType()) 3508 continue; 3509 3510 QualType ParamTypes[2] = { 3511 Context.getLValueReferenceType(*Ptr), Context.IntTy 3512 }; 3513 3514 // Without volatile 3515 if (NumArgs == 1) 3516 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3517 else 3518 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3519 3520 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 3521 VisibleTypeConversionsQuals.hasVolatile()) { 3522 // With volatile 3523 ParamTypes[0] 3524 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 3525 if (NumArgs == 1) 3526 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 3527 else 3528 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3529 } 3530 } 3531 break; 3532 3533 UnaryStar: 3534 // C++ [over.built]p6: 3535 // For every cv-qualified or cv-unqualified object type T, there 3536 // exist candidate operator functions of the form 3537 // 3538 // T& operator*(T*); 3539 // 3540 // C++ [over.built]p7: 3541 // For every function type T, there exist candidate operator 3542 // functions of the form 3543 // T& operator*(T*); 3544 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3545 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3546 QualType ParamTy = *Ptr; 3547 QualType PointeeTy = ParamTy->getAs<PointerType>()->getPointeeType(); 3548 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 3549 &ParamTy, Args, 1, CandidateSet); 3550 } 3551 break; 3552 3553 UnaryPlus: 3554 // C++ [over.built]p8: 3555 // For every type T, there exist candidate operator functions of 3556 // the form 3557 // 3558 // T* operator+(T*); 3559 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3560 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3561 QualType ParamTy = *Ptr; 3562 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 3563 } 3564 3565 // Fall through 3566 3567 UnaryMinus: 3568 // C++ [over.built]p9: 3569 // For every promoted arithmetic type T, there exist candidate 3570 // operator functions of the form 3571 // 3572 // T operator+(T); 3573 // T operator-(T); 3574 for (unsigned Arith = FirstPromotedArithmeticType; 3575 Arith < LastPromotedArithmeticType; ++Arith) { 3576 QualType ArithTy = ArithmeticTypes[Arith]; 3577 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 3578 } 3579 break; 3580 3581 case OO_Tilde: 3582 // C++ [over.built]p10: 3583 // For every promoted integral type T, there exist candidate 3584 // operator functions of the form 3585 // 3586 // T operator~(T); 3587 for (unsigned Int = FirstPromotedIntegralType; 3588 Int < LastPromotedIntegralType; ++Int) { 3589 QualType IntTy = ArithmeticTypes[Int]; 3590 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 3591 } 3592 break; 3593 3594 case OO_New: 3595 case OO_Delete: 3596 case OO_Array_New: 3597 case OO_Array_Delete: 3598 case OO_Call: 3599 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 3600 break; 3601 3602 case OO_Comma: 3603 UnaryAmp: 3604 case OO_Arrow: 3605 // C++ [over.match.oper]p3: 3606 // -- For the operator ',', the unary operator '&', or the 3607 // operator '->', the built-in candidates set is empty. 3608 break; 3609 3610 case OO_EqualEqual: 3611 case OO_ExclaimEqual: 3612 // C++ [over.match.oper]p16: 3613 // For every pointer to member type T, there exist candidate operator 3614 // functions of the form 3615 // 3616 // bool operator==(T,T); 3617 // bool operator!=(T,T); 3618 for (BuiltinCandidateTypeSet::iterator 3619 MemPtr = CandidateTypes.member_pointer_begin(), 3620 MemPtrEnd = CandidateTypes.member_pointer_end(); 3621 MemPtr != MemPtrEnd; 3622 ++MemPtr) { 3623 QualType ParamTypes[2] = { *MemPtr, *MemPtr }; 3624 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 3625 } 3626 3627 // Fall through 3628 3629 case OO_Less: 3630 case OO_Greater: 3631 case OO_LessEqual: 3632 case OO_GreaterEqual: 3633 // C++ [over.built]p15: 3634 // 3635 // For every pointer or enumeration type T, there exist 3636 // candidate operator functions of the form 3637 // 3638 // bool operator<(T, T); 3639 // bool operator>(T, T); 3640 // bool operator<=(T, T); 3641 // bool operator>=(T, T); 3642 // bool operator==(T, T); 3643 // bool operator!=(T, T); 3644 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3645 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3646 QualType ParamTypes[2] = { *Ptr, *Ptr }; 3647 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 3648 } 3649 for (BuiltinCandidateTypeSet::iterator Enum 3650 = CandidateTypes.enumeration_begin(); 3651 Enum != CandidateTypes.enumeration_end(); ++Enum) { 3652 QualType ParamTypes[2] = { *Enum, *Enum }; 3653 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 3654 } 3655 3656 // Fall through. 3657 isComparison = true; 3658 3659 BinaryPlus: 3660 BinaryMinus: 3661 if (!isComparison) { 3662 // We didn't fall through, so we must have OO_Plus or OO_Minus. 3663 3664 // C++ [over.built]p13: 3665 // 3666 // For every cv-qualified or cv-unqualified object type T 3667 // there exist candidate operator functions of the form 3668 // 3669 // T* operator+(T*, ptrdiff_t); 3670 // T& operator[](T*, ptrdiff_t); [BELOW] 3671 // T* operator-(T*, ptrdiff_t); 3672 // T* operator+(ptrdiff_t, T*); 3673 // T& operator[](ptrdiff_t, T*); [BELOW] 3674 // 3675 // C++ [over.built]p14: 3676 // 3677 // For every T, where T is a pointer to object type, there 3678 // exist candidate operator functions of the form 3679 // 3680 // ptrdiff_t operator-(T, T); 3681 for (BuiltinCandidateTypeSet::iterator Ptr 3682 = CandidateTypes.pointer_begin(); 3683 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3684 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 3685 3686 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 3687 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3688 3689 if (Op == OO_Plus) { 3690 // T* operator+(ptrdiff_t, T*); 3691 ParamTypes[0] = ParamTypes[1]; 3692 ParamTypes[1] = *Ptr; 3693 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 3694 } else { 3695 // ptrdiff_t operator-(T, T); 3696 ParamTypes[1] = *Ptr; 3697 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 3698 Args, 2, CandidateSet); 3699 } 3700 } 3701 } 3702 // Fall through 3703 3704 case OO_Slash: 3705 BinaryStar: 3706 Conditional: 3707 // C++ [over.built]p12: 3708 // 3709 // For every pair of promoted arithmetic types L and R, there 3710 // exist candidate operator functions of the form 3711 // 3712 // LR operator*(L, R); 3713 // LR operator/(L, R); 3714 // LR operator+(L, R); 3715 // LR operator-(L, R); 3716 // bool operator<(L, R); 3717 // bool operator>(L, R); 3718 // bool operator<=(L, R); 3719 // bool operator>=(L, R); 3720 // bool operator==(L, R); 3721 // bool operator!=(L, R); 3722 // 3723 // where LR is the result of the usual arithmetic conversions 3724 // between types L and R. 3725 // 3726 // C++ [over.built]p24: 3727 // 3728 // For every pair of promoted arithmetic types L and R, there exist 3729 // candidate operator functions of the form 3730 // 3731 // LR operator?(bool, L, R); 3732 // 3733 // where LR is the result of the usual arithmetic conversions 3734 // between types L and R. 3735 // Our candidates ignore the first parameter. 3736 for (unsigned Left = FirstPromotedArithmeticType; 3737 Left < LastPromotedArithmeticType; ++Left) { 3738 for (unsigned Right = FirstPromotedArithmeticType; 3739 Right < LastPromotedArithmeticType; ++Right) { 3740 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 3741 QualType Result 3742 = isComparison 3743 ? Context.BoolTy 3744 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 3745 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 3746 } 3747 } 3748 break; 3749 3750 case OO_Percent: 3751 BinaryAmp: 3752 case OO_Caret: 3753 case OO_Pipe: 3754 case OO_LessLess: 3755 case OO_GreaterGreater: 3756 // C++ [over.built]p17: 3757 // 3758 // For every pair of promoted integral types L and R, there 3759 // exist candidate operator functions of the form 3760 // 3761 // LR operator%(L, R); 3762 // LR operator&(L, R); 3763 // LR operator^(L, R); 3764 // LR operator|(L, R); 3765 // L operator<<(L, R); 3766 // L operator>>(L, R); 3767 // 3768 // where LR is the result of the usual arithmetic conversions 3769 // between types L and R. 3770 for (unsigned Left = FirstPromotedIntegralType; 3771 Left < LastPromotedIntegralType; ++Left) { 3772 for (unsigned Right = FirstPromotedIntegralType; 3773 Right < LastPromotedIntegralType; ++Right) { 3774 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 3775 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 3776 ? LandR[0] 3777 : Context.UsualArithmeticConversionsType(LandR[0], LandR[1]); 3778 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 3779 } 3780 } 3781 break; 3782 3783 case OO_Equal: 3784 // C++ [over.built]p20: 3785 // 3786 // For every pair (T, VQ), where T is an enumeration or 3787 // pointer to member type and VQ is either volatile or 3788 // empty, there exist candidate operator functions of the form 3789 // 3790 // VQ T& operator=(VQ T&, T); 3791 for (BuiltinCandidateTypeSet::iterator 3792 Enum = CandidateTypes.enumeration_begin(), 3793 EnumEnd = CandidateTypes.enumeration_end(); 3794 Enum != EnumEnd; ++Enum) 3795 AddBuiltinAssignmentOperatorCandidates(*this, *Enum, Args, 2, 3796 CandidateSet); 3797 for (BuiltinCandidateTypeSet::iterator 3798 MemPtr = CandidateTypes.member_pointer_begin(), 3799 MemPtrEnd = CandidateTypes.member_pointer_end(); 3800 MemPtr != MemPtrEnd; ++MemPtr) 3801 AddBuiltinAssignmentOperatorCandidates(*this, *MemPtr, Args, 2, 3802 CandidateSet); 3803 // Fall through. 3804 3805 case OO_PlusEqual: 3806 case OO_MinusEqual: 3807 // C++ [over.built]p19: 3808 // 3809 // For every pair (T, VQ), where T is any type and VQ is either 3810 // volatile or empty, there exist candidate operator functions 3811 // of the form 3812 // 3813 // T*VQ& operator=(T*VQ&, T*); 3814 // 3815 // C++ [over.built]p21: 3816 // 3817 // For every pair (T, VQ), where T is a cv-qualified or 3818 // cv-unqualified object type and VQ is either volatile or 3819 // empty, there exist candidate operator functions of the form 3820 // 3821 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 3822 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 3823 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3824 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3825 QualType ParamTypes[2]; 3826 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 3827 3828 // non-volatile version 3829 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 3830 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3831 /*IsAssigmentOperator=*/Op == OO_Equal); 3832 3833 if (!Context.getCanonicalType(*Ptr).isVolatileQualified() && 3834 VisibleTypeConversionsQuals.hasVolatile()) { 3835 // volatile version 3836 ParamTypes[0] 3837 = Context.getLValueReferenceType(Context.getVolatileType(*Ptr)); 3838 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3839 /*IsAssigmentOperator=*/Op == OO_Equal); 3840 } 3841 } 3842 // Fall through. 3843 3844 case OO_StarEqual: 3845 case OO_SlashEqual: 3846 // C++ [over.built]p18: 3847 // 3848 // For every triple (L, VQ, R), where L is an arithmetic type, 3849 // VQ is either volatile or empty, and R is a promoted 3850 // arithmetic type, there exist candidate operator functions of 3851 // the form 3852 // 3853 // VQ L& operator=(VQ L&, R); 3854 // VQ L& operator*=(VQ L&, R); 3855 // VQ L& operator/=(VQ L&, R); 3856 // VQ L& operator+=(VQ L&, R); 3857 // VQ L& operator-=(VQ L&, R); 3858 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 3859 for (unsigned Right = FirstPromotedArithmeticType; 3860 Right < LastPromotedArithmeticType; ++Right) { 3861 QualType ParamTypes[2]; 3862 ParamTypes[1] = ArithmeticTypes[Right]; 3863 3864 // Add this built-in operator as a candidate (VQ is empty). 3865 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3866 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3867 /*IsAssigmentOperator=*/Op == OO_Equal); 3868 3869 // Add this built-in operator as a candidate (VQ is 'volatile'). 3870 if (VisibleTypeConversionsQuals.hasVolatile()) { 3871 ParamTypes[0] = Context.getVolatileType(ArithmeticTypes[Left]); 3872 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3873 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3874 /*IsAssigmentOperator=*/Op == OO_Equal); 3875 } 3876 } 3877 } 3878 break; 3879 3880 case OO_PercentEqual: 3881 case OO_LessLessEqual: 3882 case OO_GreaterGreaterEqual: 3883 case OO_AmpEqual: 3884 case OO_CaretEqual: 3885 case OO_PipeEqual: 3886 // C++ [over.built]p22: 3887 // 3888 // For every triple (L, VQ, R), where L is an integral type, VQ 3889 // is either volatile or empty, and R is a promoted integral 3890 // type, there exist candidate operator functions of the form 3891 // 3892 // VQ L& operator%=(VQ L&, R); 3893 // VQ L& operator<<=(VQ L&, R); 3894 // VQ L& operator>>=(VQ L&, R); 3895 // VQ L& operator&=(VQ L&, R); 3896 // VQ L& operator^=(VQ L&, R); 3897 // VQ L& operator|=(VQ L&, R); 3898 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 3899 for (unsigned Right = FirstPromotedIntegralType; 3900 Right < LastPromotedIntegralType; ++Right) { 3901 QualType ParamTypes[2]; 3902 ParamTypes[1] = ArithmeticTypes[Right]; 3903 3904 // Add this built-in operator as a candidate (VQ is empty). 3905 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3906 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3907 if (VisibleTypeConversionsQuals.hasVolatile()) { 3908 // Add this built-in operator as a candidate (VQ is 'volatile'). 3909 ParamTypes[0] = ArithmeticTypes[Left]; 3910 ParamTypes[0] = Context.getVolatileType(ParamTypes[0]); 3911 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3912 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3913 } 3914 } 3915 } 3916 break; 3917 3918 case OO_Exclaim: { 3919 // C++ [over.operator]p23: 3920 // 3921 // There also exist candidate operator functions of the form 3922 // 3923 // bool operator!(bool); 3924 // bool operator&&(bool, bool); [BELOW] 3925 // bool operator||(bool, bool); [BELOW] 3926 QualType ParamTy = Context.BoolTy; 3927 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 3928 /*IsAssignmentOperator=*/false, 3929 /*NumContextualBoolArguments=*/1); 3930 break; 3931 } 3932 3933 case OO_AmpAmp: 3934 case OO_PipePipe: { 3935 // C++ [over.operator]p23: 3936 // 3937 // There also exist candidate operator functions of the form 3938 // 3939 // bool operator!(bool); [ABOVE] 3940 // bool operator&&(bool, bool); 3941 // bool operator||(bool, bool); 3942 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 3943 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 3944 /*IsAssignmentOperator=*/false, 3945 /*NumContextualBoolArguments=*/2); 3946 break; 3947 } 3948 3949 case OO_Subscript: 3950 // C++ [over.built]p13: 3951 // 3952 // For every cv-qualified or cv-unqualified object type T there 3953 // exist candidate operator functions of the form 3954 // 3955 // T* operator+(T*, ptrdiff_t); [ABOVE] 3956 // T& operator[](T*, ptrdiff_t); 3957 // T* operator-(T*, ptrdiff_t); [ABOVE] 3958 // T* operator+(ptrdiff_t, T*); [ABOVE] 3959 // T& operator[](ptrdiff_t, T*); 3960 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3961 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3962 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 3963 QualType PointeeType = (*Ptr)->getAs<PointerType>()->getPointeeType(); 3964 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 3965 3966 // T& operator[](T*, ptrdiff_t) 3967 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3968 3969 // T& operator[](ptrdiff_t, T*); 3970 ParamTypes[0] = ParamTypes[1]; 3971 ParamTypes[1] = *Ptr; 3972 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3973 } 3974 break; 3975 3976 case OO_ArrowStar: 3977 // C++ [over.built]p11: 3978 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type, 3979 // C1 is the same type as C2 or is a derived class of C2, T is an object 3980 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs, 3981 // there exist candidate operator functions of the form 3982 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*); 3983 // where CV12 is the union of CV1 and CV2. 3984 { 3985 for (BuiltinCandidateTypeSet::iterator Ptr = 3986 CandidateTypes.pointer_begin(); 3987 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3988 QualType C1Ty = (*Ptr); 3989 QualType C1; 3990 QualifierCollector Q1; 3991 if (const PointerType *PointerTy = C1Ty->getAs<PointerType>()) { 3992 C1 = QualType(Q1.strip(PointerTy->getPointeeType()), 0); 3993 if (!isa<RecordType>(C1)) 3994 continue; 3995 // heuristic to reduce number of builtin candidates in the set. 3996 // Add volatile/restrict version only if there are conversions to a 3997 // volatile/restrict type. 3998 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile()) 3999 continue; 4000 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict()) 4001 continue; 4002 } 4003 for (BuiltinCandidateTypeSet::iterator 4004 MemPtr = CandidateTypes.member_pointer_begin(), 4005 MemPtrEnd = CandidateTypes.member_pointer_end(); 4006 MemPtr != MemPtrEnd; ++MemPtr) { 4007 const MemberPointerType *mptr = cast<MemberPointerType>(*MemPtr); 4008 QualType C2 = QualType(mptr->getClass(), 0); 4009 C2 = C2.getUnqualifiedType(); 4010 if (C1 != C2 && !IsDerivedFrom(C1, C2)) 4011 break; 4012 QualType ParamTypes[2] = { *Ptr, *MemPtr }; 4013 // build CV12 T& 4014 QualType T = mptr->getPointeeType(); 4015 if (!VisibleTypeConversionsQuals.hasVolatile() && 4016 T.isVolatileQualified()) 4017 continue; 4018 if (!VisibleTypeConversionsQuals.hasRestrict() && 4019 T.isRestrictQualified()) 4020 continue; 4021 T = Q1.apply(T); 4022 QualType ResultTy = Context.getLValueReferenceType(T); 4023 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 4024 } 4025 } 4026 } 4027 break; 4028 4029 case OO_Conditional: 4030 // Note that we don't consider the first argument, since it has been 4031 // contextually converted to bool long ago. The candidates below are 4032 // therefore added as binary. 4033 // 4034 // C++ [over.built]p24: 4035 // For every type T, where T is a pointer or pointer-to-member type, 4036 // there exist candidate operator functions of the form 4037 // 4038 // T operator?(bool, T, T); 4039 // 4040 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(), 4041 E = CandidateTypes.pointer_end(); Ptr != E; ++Ptr) { 4042 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4043 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4044 } 4045 for (BuiltinCandidateTypeSet::iterator Ptr = 4046 CandidateTypes.member_pointer_begin(), 4047 E = CandidateTypes.member_pointer_end(); Ptr != E; ++Ptr) { 4048 QualType ParamTypes[2] = { *Ptr, *Ptr }; 4049 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 4050 } 4051 goto Conditional; 4052 } 4053} 4054 4055/// \brief Add function candidates found via argument-dependent lookup 4056/// to the set of overloading candidates. 4057/// 4058/// This routine performs argument-dependent name lookup based on the 4059/// given function name (which may also be an operator name) and adds 4060/// all of the overload candidates found by ADL to the overload 4061/// candidate set (C++ [basic.lookup.argdep]). 4062void 4063Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 4064 Expr **Args, unsigned NumArgs, 4065 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4066 OverloadCandidateSet& CandidateSet, 4067 bool PartialOverloading) { 4068 FunctionSet Functions; 4069 4070 // FIXME: Should we be trafficking in canonical function decls throughout? 4071 4072 // Record all of the function candidates that we've already 4073 // added to the overload set, so that we don't add those same 4074 // candidates a second time. 4075 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4076 CandEnd = CandidateSet.end(); 4077 Cand != CandEnd; ++Cand) 4078 if (Cand->Function) { 4079 Functions.insert(Cand->Function); 4080 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4081 Functions.insert(FunTmpl); 4082 } 4083 4084 // FIXME: Pass in the explicit template arguments? 4085 ArgumentDependentLookup(Name, /*Operator*/false, Args, NumArgs, Functions); 4086 4087 // Erase all of the candidates we already knew about. 4088 // FIXME: This is suboptimal. Is there a better way? 4089 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4090 CandEnd = CandidateSet.end(); 4091 Cand != CandEnd; ++Cand) 4092 if (Cand->Function) { 4093 Functions.erase(Cand->Function); 4094 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate()) 4095 Functions.erase(FunTmpl); 4096 } 4097 4098 // For each of the ADL candidates we found, add it to the overload 4099 // set. 4100 for (FunctionSet::iterator Func = Functions.begin(), 4101 FuncEnd = Functions.end(); 4102 Func != FuncEnd; ++Func) { 4103 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*Func)) { 4104 if (ExplicitTemplateArgs) 4105 continue; 4106 4107 AddOverloadCandidate(FD, Args, NumArgs, CandidateSet, 4108 false, false, PartialOverloading); 4109 } else 4110 AddTemplateOverloadCandidate(cast<FunctionTemplateDecl>(*Func), 4111 ExplicitTemplateArgs, 4112 Args, NumArgs, CandidateSet); 4113 } 4114} 4115 4116/// isBetterOverloadCandidate - Determines whether the first overload 4117/// candidate is a better candidate than the second (C++ 13.3.3p1). 4118bool 4119Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 4120 const OverloadCandidate& Cand2) { 4121 // Define viable functions to be better candidates than non-viable 4122 // functions. 4123 if (!Cand2.Viable) 4124 return Cand1.Viable; 4125 else if (!Cand1.Viable) 4126 return false; 4127 4128 // C++ [over.match.best]p1: 4129 // 4130 // -- if F is a static member function, ICS1(F) is defined such 4131 // that ICS1(F) is neither better nor worse than ICS1(G) for 4132 // any function G, and, symmetrically, ICS1(G) is neither 4133 // better nor worse than ICS1(F). 4134 unsigned StartArg = 0; 4135 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 4136 StartArg = 1; 4137 4138 // C++ [over.match.best]p1: 4139 // A viable function F1 is defined to be a better function than another 4140 // viable function F2 if for all arguments i, ICSi(F1) is not a worse 4141 // conversion sequence than ICSi(F2), and then... 4142 unsigned NumArgs = Cand1.Conversions.size(); 4143 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 4144 bool HasBetterConversion = false; 4145 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 4146 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 4147 Cand2.Conversions[ArgIdx])) { 4148 case ImplicitConversionSequence::Better: 4149 // Cand1 has a better conversion sequence. 4150 HasBetterConversion = true; 4151 break; 4152 4153 case ImplicitConversionSequence::Worse: 4154 // Cand1 can't be better than Cand2. 4155 return false; 4156 4157 case ImplicitConversionSequence::Indistinguishable: 4158 // Do nothing. 4159 break; 4160 } 4161 } 4162 4163 // -- for some argument j, ICSj(F1) is a better conversion sequence than 4164 // ICSj(F2), or, if not that, 4165 if (HasBetterConversion) 4166 return true; 4167 4168 // - F1 is a non-template function and F2 is a function template 4169 // specialization, or, if not that, 4170 if (Cand1.Function && !Cand1.Function->getPrimaryTemplate() && 4171 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4172 return true; 4173 4174 // -- F1 and F2 are function template specializations, and the function 4175 // template for F1 is more specialized than the template for F2 4176 // according to the partial ordering rules described in 14.5.5.2, or, 4177 // if not that, 4178 if (Cand1.Function && Cand1.Function->getPrimaryTemplate() && 4179 Cand2.Function && Cand2.Function->getPrimaryTemplate()) 4180 if (FunctionTemplateDecl *BetterTemplate 4181 = getMoreSpecializedTemplate(Cand1.Function->getPrimaryTemplate(), 4182 Cand2.Function->getPrimaryTemplate(), 4183 isa<CXXConversionDecl>(Cand1.Function)? TPOC_Conversion 4184 : TPOC_Call)) 4185 return BetterTemplate == Cand1.Function->getPrimaryTemplate(); 4186 4187 // -- the context is an initialization by user-defined conversion 4188 // (see 8.5, 13.3.1.5) and the standard conversion sequence 4189 // from the return type of F1 to the destination type (i.e., 4190 // the type of the entity being initialized) is a better 4191 // conversion sequence than the standard conversion sequence 4192 // from the return type of F2 to the destination type. 4193 if (Cand1.Function && Cand2.Function && 4194 isa<CXXConversionDecl>(Cand1.Function) && 4195 isa<CXXConversionDecl>(Cand2.Function)) { 4196 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 4197 Cand2.FinalConversion)) { 4198 case ImplicitConversionSequence::Better: 4199 // Cand1 has a better conversion sequence. 4200 return true; 4201 4202 case ImplicitConversionSequence::Worse: 4203 // Cand1 can't be better than Cand2. 4204 return false; 4205 4206 case ImplicitConversionSequence::Indistinguishable: 4207 // Do nothing 4208 break; 4209 } 4210 } 4211 4212 return false; 4213} 4214 4215/// \brief Computes the best viable function (C++ 13.3.3) 4216/// within an overload candidate set. 4217/// 4218/// \param CandidateSet the set of candidate functions. 4219/// 4220/// \param Loc the location of the function name (or operator symbol) for 4221/// which overload resolution occurs. 4222/// 4223/// \param Best f overload resolution was successful or found a deleted 4224/// function, Best points to the candidate function found. 4225/// 4226/// \returns The result of overload resolution. 4227OverloadingResult Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 4228 SourceLocation Loc, 4229 OverloadCandidateSet::iterator& Best) { 4230 // Find the best viable function. 4231 Best = CandidateSet.end(); 4232 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4233 Cand != CandidateSet.end(); ++Cand) { 4234 if (Cand->Viable) { 4235 if (Best == CandidateSet.end() || isBetterOverloadCandidate(*Cand, *Best)) 4236 Best = Cand; 4237 } 4238 } 4239 4240 // If we didn't find any viable functions, abort. 4241 if (Best == CandidateSet.end()) 4242 return OR_No_Viable_Function; 4243 4244 // Make sure that this function is better than every other viable 4245 // function. If not, we have an ambiguity. 4246 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 4247 Cand != CandidateSet.end(); ++Cand) { 4248 if (Cand->Viable && 4249 Cand != Best && 4250 !isBetterOverloadCandidate(*Best, *Cand)) { 4251 Best = CandidateSet.end(); 4252 return OR_Ambiguous; 4253 } 4254 } 4255 4256 // Best is the best viable function. 4257 if (Best->Function && 4258 (Best->Function->isDeleted() || 4259 Best->Function->getAttr<UnavailableAttr>())) 4260 return OR_Deleted; 4261 4262 // C++ [basic.def.odr]p2: 4263 // An overloaded function is used if it is selected by overload resolution 4264 // when referred to from a potentially-evaluated expression. [Note: this 4265 // covers calls to named functions (5.2.2), operator overloading 4266 // (clause 13), user-defined conversions (12.3.2), allocation function for 4267 // placement new (5.3.4), as well as non-default initialization (8.5). 4268 if (Best->Function) 4269 MarkDeclarationReferenced(Loc, Best->Function); 4270 return OR_Success; 4271} 4272 4273/// Notes the location of an overload candidate. 4274void Sema::NoteOverloadCandidate(FunctionDecl *Fn) { 4275 4276 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) { 4277 // At least call it a 'constructor'. 4278 if (!Ctor->isImplicit()) { 4279 Diag(Ctor->getLocation(), diag::note_ovl_candidate_ctor); 4280 return; 4281 } 4282 4283 CXXRecordDecl *Record = Ctor->getParent(); 4284 if (Ctor->isCopyConstructor()) { 4285 Diag(Record->getLocation(), diag::note_ovl_candidate_implicit_copy_ctor); 4286 return; 4287 } 4288 4289 Diag(Record->getLocation(), diag::note_ovl_candidate_implicit_default_ctor); 4290 return; 4291 } 4292 4293 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) { 4294 // This actually gets spelled 'candidate function' for now, but 4295 // it doesn't hurt to split it out. 4296 if (!Meth->isImplicit()) { 4297 Diag(Meth->getLocation(), diag::note_ovl_candidate_meth); 4298 return; 4299 } 4300 4301 assert(Meth->isCopyAssignment() 4302 && "implicit method is not copy assignment operator?"); 4303 Diag(Meth->getParent()->getLocation(), 4304 diag::note_ovl_candidate_implicit_copy_assign); 4305 return; 4306 } 4307 4308 Diag(Fn->getLocation(), diag::note_ovl_candidate); 4309} 4310 4311namespace { 4312 4313void NoteDeletedCandidate(Sema &S, OverloadCandidate *Cand) { 4314} 4315 4316void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand) { 4317 // Note deleted candidates, but only if they're viable. 4318 if (Cand->Viable && 4319 (Cand->Function->isDeleted() || 4320 Cand->Function->hasAttr<UnavailableAttr>())) { 4321 S.Diag(Cand->Function->getLocation(), diag::note_ovl_candidate_deleted) 4322 << Cand->Function->isDeleted(); 4323 return; 4324 } 4325 4326 if (FunctionTemplateDecl *FunTmpl 4327 = Cand->Function->getPrimaryTemplate()) { 4328 // Function template specialization 4329 // FIXME: Give a better reason! 4330 S.Diag(Cand->Function->getLocation(), diag::note_ovl_template_candidate) 4331 << S.getTemplateArgumentBindingsText(FunTmpl->getTemplateParameters(), 4332 *Cand->Function->getTemplateSpecializationArgs()); 4333 return; 4334 } 4335 4336 // Normal function 4337 bool errReported = false; 4338 if (!Cand->Viable && Cand->Conversions.size() > 0) { 4339 for (int i = Cand->Conversions.size()-1; i >= 0; i--) { 4340 const ImplicitConversionSequence &Conversion = 4341 Cand->Conversions[i]; 4342 if ((Conversion.ConversionKind != 4343 ImplicitConversionSequence::BadConversion) || 4344 Conversion.ConversionFunctionSet.size() == 0) 4345 continue; 4346 S.Diag(Cand->Function->getLocation(), 4347 diag::note_ovl_candidate_not_viable) << (i+1); 4348 errReported = true; 4349 for (int j = Conversion.ConversionFunctionSet.size()-1; 4350 j >= 0; j--) { 4351 FunctionDecl *Func = Conversion.ConversionFunctionSet[j]; 4352 S.NoteOverloadCandidate(Func); 4353 } 4354 } 4355 } 4356 4357 if (!errReported) 4358 S.NoteOverloadCandidate(Cand->Function); 4359} 4360 4361void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) { 4362 // Desugar the type of the surrogate down to a function type, 4363 // retaining as many typedefs as possible while still showing 4364 // the function type (and, therefore, its parameter types). 4365 QualType FnType = Cand->Surrogate->getConversionType(); 4366 bool isLValueReference = false; 4367 bool isRValueReference = false; 4368 bool isPointer = false; 4369 if (const LValueReferenceType *FnTypeRef = 4370 FnType->getAs<LValueReferenceType>()) { 4371 FnType = FnTypeRef->getPointeeType(); 4372 isLValueReference = true; 4373 } else if (const RValueReferenceType *FnTypeRef = 4374 FnType->getAs<RValueReferenceType>()) { 4375 FnType = FnTypeRef->getPointeeType(); 4376 isRValueReference = true; 4377 } 4378 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) { 4379 FnType = FnTypePtr->getPointeeType(); 4380 isPointer = true; 4381 } 4382 // Desugar down to a function type. 4383 FnType = QualType(FnType->getAs<FunctionType>(), 0); 4384 // Reconstruct the pointer/reference as appropriate. 4385 if (isPointer) FnType = S.Context.getPointerType(FnType); 4386 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType); 4387 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType); 4388 4389 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand) 4390 << FnType; 4391} 4392 4393void NoteBuiltinOperatorCandidate(Sema &S, 4394 const char *Opc, 4395 SourceLocation OpLoc, 4396 OverloadCandidate *Cand) { 4397 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary"); 4398 std::string TypeStr("operator"); 4399 TypeStr += Opc; 4400 TypeStr += "("; 4401 TypeStr += Cand->BuiltinTypes.ParamTypes[0].getAsString(); 4402 if (Cand->Conversions.size() == 1) { 4403 TypeStr += ")"; 4404 S.Diag(OpLoc, diag::note_ovl_builtin_unary_candidate) << TypeStr; 4405 } else { 4406 TypeStr += ", "; 4407 TypeStr += Cand->BuiltinTypes.ParamTypes[1].getAsString(); 4408 TypeStr += ")"; 4409 S.Diag(OpLoc, diag::note_ovl_builtin_binary_candidate) << TypeStr; 4410 } 4411} 4412 4413void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc, 4414 OverloadCandidate *Cand) { 4415 unsigned NoOperands = Cand->Conversions.size(); 4416 for (unsigned ArgIdx = 0; ArgIdx < NoOperands; ++ArgIdx) { 4417 const ImplicitConversionSequence &ICS = Cand->Conversions[ArgIdx]; 4418 if (ICS.ConversionKind != ImplicitConversionSequence::BadConversion || 4419 ICS.ConversionFunctionSet.empty()) 4420 continue; 4421 if (CXXConversionDecl *Func = dyn_cast<CXXConversionDecl>( 4422 Cand->Conversions[ArgIdx].ConversionFunctionSet[0])) { 4423 QualType FromTy = 4424 QualType(static_cast<Type*>(ICS.UserDefined.Before.FromTypePtr),0); 4425 S.Diag(OpLoc, diag::note_ambiguous_type_conversion) 4426 << FromTy << Func->getConversionType(); 4427 } 4428 for (unsigned j = 0; j < ICS.ConversionFunctionSet.size(); j++) { 4429 FunctionDecl *Func = 4430 Cand->Conversions[ArgIdx].ConversionFunctionSet[j]; 4431 S.NoteOverloadCandidate(Func); 4432 } 4433 } 4434} 4435 4436struct CompareOverloadCandidates { 4437 SourceManager &SM; 4438 CompareOverloadCandidates(SourceManager &SM) : SM(SM) {} 4439 4440 bool operator()(const OverloadCandidate *L, 4441 const OverloadCandidate *R) { 4442 // Order first by viability. 4443 if (L->Viable != R->Viable) 4444 return L->Viable; 4445 4446 // Put declared functions first. 4447 if (L->Function) { 4448 if (!R->Function) return true; 4449 return SM.isBeforeInTranslationUnit(L->Function->getLocation(), 4450 R->Function->getLocation()); 4451 } else if (R->Function) return false; 4452 4453 // Then surrogates. 4454 if (L->IsSurrogate) { 4455 if (!R->IsSurrogate) return true; 4456 return SM.isBeforeInTranslationUnit(L->Surrogate->getLocation(), 4457 R->Surrogate->getLocation()); 4458 } else if (R->IsSurrogate) return false; 4459 4460 // And builtins just come in a jumble. 4461 return false; 4462 } 4463}; 4464 4465} // end anonymous namespace 4466 4467/// PrintOverloadCandidates - When overload resolution fails, prints 4468/// diagnostic messages containing the candidates in the candidate 4469/// set. 4470void 4471Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 4472 OverloadCandidateDisplayKind OCD, 4473 const char *Opc, 4474 SourceLocation OpLoc) { 4475 // Sort the candidates by viability and position. Sorting directly would 4476 // be prohibitive, so we make a set of pointers and sort those. 4477 llvm::SmallVector<OverloadCandidate*, 32> Cands; 4478 if (OCD == OCD_AllCandidates) Cands.reserve(CandidateSet.size()); 4479 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 4480 LastCand = CandidateSet.end(); 4481 Cand != LastCand; ++Cand) 4482 if (Cand->Viable || OCD == OCD_AllCandidates) 4483 Cands.push_back(Cand); 4484 std::sort(Cands.begin(), Cands.end(), CompareOverloadCandidates(SourceMgr)); 4485 4486 bool ReportedNonViableOperator = false; 4487 4488 llvm::SmallVectorImpl<OverloadCandidate*>::iterator I, E; 4489 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) { 4490 OverloadCandidate *Cand = *I; 4491 4492 if (Cand->Function) 4493 NoteFunctionCandidate(*this, Cand); 4494 else if (Cand->IsSurrogate) 4495 NoteSurrogateCandidate(*this, Cand); 4496 4497 // This a builtin candidate. We do not, in general, want to list 4498 // every possible builtin candidate. 4499 4500 // If this is a viable builtin, print it. 4501 else if (Cand->Viable) 4502 NoteBuiltinOperatorCandidate(*this, Opc, OpLoc, Cand); 4503 4504 // Otherwise, non-viability might be due to ambiguous user-defined 4505 // conversions. Report them exactly once. 4506 else if (!ReportedNonViableOperator) { 4507 NoteAmbiguousUserConversions(*this, OpLoc, Cand); 4508 ReportedNonViableOperator = true; 4509 } 4510 } 4511} 4512 4513/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 4514/// an overloaded function (C++ [over.over]), where @p From is an 4515/// expression with overloaded function type and @p ToType is the type 4516/// we're trying to resolve to. For example: 4517/// 4518/// @code 4519/// int f(double); 4520/// int f(int); 4521/// 4522/// int (*pfd)(double) = f; // selects f(double) 4523/// @endcode 4524/// 4525/// This routine returns the resulting FunctionDecl if it could be 4526/// resolved, and NULL otherwise. When @p Complain is true, this 4527/// routine will emit diagnostics if there is an error. 4528FunctionDecl * 4529Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 4530 bool Complain) { 4531 QualType FunctionType = ToType; 4532 bool IsMember = false; 4533 if (const PointerType *ToTypePtr = ToType->getAs<PointerType>()) 4534 FunctionType = ToTypePtr->getPointeeType(); 4535 else if (const ReferenceType *ToTypeRef = ToType->getAs<ReferenceType>()) 4536 FunctionType = ToTypeRef->getPointeeType(); 4537 else if (const MemberPointerType *MemTypePtr = 4538 ToType->getAs<MemberPointerType>()) { 4539 FunctionType = MemTypePtr->getPointeeType(); 4540 IsMember = true; 4541 } 4542 4543 // We only look at pointers or references to functions. 4544 FunctionType = Context.getCanonicalType(FunctionType).getUnqualifiedType(); 4545 if (!FunctionType->isFunctionType()) 4546 return 0; 4547 4548 // Find the actual overloaded function declaration. 4549 4550 // C++ [over.over]p1: 4551 // [...] [Note: any redundant set of parentheses surrounding the 4552 // overloaded function name is ignored (5.1). ] 4553 Expr *OvlExpr = From->IgnoreParens(); 4554 4555 // C++ [over.over]p1: 4556 // [...] The overloaded function name can be preceded by the & 4557 // operator. 4558 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(OvlExpr)) { 4559 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 4560 OvlExpr = UnOp->getSubExpr()->IgnoreParens(); 4561 } 4562 4563 bool HasExplicitTemplateArgs = false; 4564 TemplateArgumentListInfo ExplicitTemplateArgs; 4565 4566 llvm::SmallVector<NamedDecl*,8> Fns; 4567 4568 // Look into the overloaded expression. 4569 if (UnresolvedLookupExpr *UL 4570 = dyn_cast<UnresolvedLookupExpr>(OvlExpr)) { 4571 Fns.append(UL->decls_begin(), UL->decls_end()); 4572 if (UL->hasExplicitTemplateArgs()) { 4573 HasExplicitTemplateArgs = true; 4574 UL->copyTemplateArgumentsInto(ExplicitTemplateArgs); 4575 } 4576 } else if (UnresolvedMemberExpr *ME 4577 = dyn_cast<UnresolvedMemberExpr>(OvlExpr)) { 4578 Fns.append(ME->decls_begin(), ME->decls_end()); 4579 if (ME->hasExplicitTemplateArgs()) { 4580 HasExplicitTemplateArgs = true; 4581 ME->copyTemplateArgumentsInto(ExplicitTemplateArgs); 4582 } 4583 } 4584 4585 // If we didn't actually find anything, we're done. 4586 if (Fns.empty()) 4587 return 0; 4588 4589 // Look through all of the overloaded functions, searching for one 4590 // whose type matches exactly. 4591 llvm::SmallPtrSet<FunctionDecl *, 4> Matches; 4592 bool FoundNonTemplateFunction = false; 4593 for (llvm::SmallVectorImpl<NamedDecl*>::iterator I = Fns.begin(), 4594 E = Fns.end(); I != E; ++I) { 4595 // Look through any using declarations to find the underlying function. 4596 NamedDecl *Fn = (*I)->getUnderlyingDecl(); 4597 4598 // C++ [over.over]p3: 4599 // Non-member functions and static member functions match 4600 // targets of type "pointer-to-function" or "reference-to-function." 4601 // Nonstatic member functions match targets of 4602 // type "pointer-to-member-function." 4603 // Note that according to DR 247, the containing class does not matter. 4604 4605 if (FunctionTemplateDecl *FunctionTemplate 4606 = dyn_cast<FunctionTemplateDecl>(Fn)) { 4607 if (CXXMethodDecl *Method 4608 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) { 4609 // Skip non-static function templates when converting to pointer, and 4610 // static when converting to member pointer. 4611 if (Method->isStatic() == IsMember) 4612 continue; 4613 } else if (IsMember) 4614 continue; 4615 4616 // C++ [over.over]p2: 4617 // If the name is a function template, template argument deduction is 4618 // done (14.8.2.2), and if the argument deduction succeeds, the 4619 // resulting template argument list is used to generate a single 4620 // function template specialization, which is added to the set of 4621 // overloaded functions considered. 4622 // FIXME: We don't really want to build the specialization here, do we? 4623 FunctionDecl *Specialization = 0; 4624 TemplateDeductionInfo Info(Context); 4625 if (TemplateDeductionResult Result 4626 = DeduceTemplateArguments(FunctionTemplate, 4627 (HasExplicitTemplateArgs ? &ExplicitTemplateArgs : 0), 4628 FunctionType, Specialization, Info)) { 4629 // FIXME: make a note of the failed deduction for diagnostics. 4630 (void)Result; 4631 } else { 4632 // FIXME: If the match isn't exact, shouldn't we just drop this as 4633 // a candidate? Find a testcase before changing the code. 4634 assert(FunctionType 4635 == Context.getCanonicalType(Specialization->getType())); 4636 Matches.insert( 4637 cast<FunctionDecl>(Specialization->getCanonicalDecl())); 4638 } 4639 4640 continue; 4641 } 4642 4643 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 4644 // Skip non-static functions when converting to pointer, and static 4645 // when converting to member pointer. 4646 if (Method->isStatic() == IsMember) 4647 continue; 4648 4649 // If we have explicit template arguments, skip non-templates. 4650 if (HasExplicitTemplateArgs) 4651 continue; 4652 } else if (IsMember) 4653 continue; 4654 4655 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) { 4656 QualType ResultTy; 4657 if (Context.hasSameUnqualifiedType(FunctionType, FunDecl->getType()) || 4658 IsNoReturnConversion(Context, FunDecl->getType(), FunctionType, 4659 ResultTy)) { 4660 Matches.insert(cast<FunctionDecl>(FunDecl->getCanonicalDecl())); 4661 FoundNonTemplateFunction = true; 4662 } 4663 } 4664 } 4665 4666 // If there were 0 or 1 matches, we're done. 4667 if (Matches.empty()) 4668 return 0; 4669 else if (Matches.size() == 1) { 4670 FunctionDecl *Result = *Matches.begin(); 4671 MarkDeclarationReferenced(From->getLocStart(), Result); 4672 return Result; 4673 } 4674 4675 // C++ [over.over]p4: 4676 // If more than one function is selected, [...] 4677 typedef llvm::SmallPtrSet<FunctionDecl *, 4>::iterator MatchIter; 4678 if (!FoundNonTemplateFunction) { 4679 // [...] and any given function template specialization F1 is 4680 // eliminated if the set contains a second function template 4681 // specialization whose function template is more specialized 4682 // than the function template of F1 according to the partial 4683 // ordering rules of 14.5.5.2. 4684 4685 // The algorithm specified above is quadratic. We instead use a 4686 // two-pass algorithm (similar to the one used to identify the 4687 // best viable function in an overload set) that identifies the 4688 // best function template (if it exists). 4689 llvm::SmallVector<FunctionDecl *, 8> TemplateMatches(Matches.begin(), 4690 Matches.end()); 4691 FunctionDecl *Result = 4692 getMostSpecialized(TemplateMatches.data(), TemplateMatches.size(), 4693 TPOC_Other, From->getLocStart(), 4694 PDiag(), 4695 PDiag(diag::err_addr_ovl_ambiguous) 4696 << TemplateMatches[0]->getDeclName(), 4697 PDiag(diag::note_ovl_template_candidate)); 4698 MarkDeclarationReferenced(From->getLocStart(), Result); 4699 return Result; 4700 } 4701 4702 // [...] any function template specializations in the set are 4703 // eliminated if the set also contains a non-template function, [...] 4704 llvm::SmallVector<FunctionDecl *, 4> RemainingMatches; 4705 for (MatchIter M = Matches.begin(), MEnd = Matches.end(); M != MEnd; ++M) 4706 if ((*M)->getPrimaryTemplate() == 0) 4707 RemainingMatches.push_back(*M); 4708 4709 // [...] After such eliminations, if any, there shall remain exactly one 4710 // selected function. 4711 if (RemainingMatches.size() == 1) { 4712 FunctionDecl *Result = RemainingMatches.front(); 4713 MarkDeclarationReferenced(From->getLocStart(), Result); 4714 return Result; 4715 } 4716 4717 // FIXME: We should probably return the same thing that BestViableFunction 4718 // returns (even if we issue the diagnostics here). 4719 Diag(From->getLocStart(), diag::err_addr_ovl_ambiguous) 4720 << RemainingMatches[0]->getDeclName(); 4721 for (unsigned I = 0, N = RemainingMatches.size(); I != N; ++I) 4722 NoteOverloadCandidate(RemainingMatches[I]); 4723 return 0; 4724} 4725 4726/// \brief Given an expression that refers to an overloaded function, try to 4727/// resolve that overloaded function expression down to a single function. 4728/// 4729/// This routine can only resolve template-ids that refer to a single function 4730/// template, where that template-id refers to a single template whose template 4731/// arguments are either provided by the template-id or have defaults, 4732/// as described in C++0x [temp.arg.explicit]p3. 4733FunctionDecl *Sema::ResolveSingleFunctionTemplateSpecialization(Expr *From) { 4734 // C++ [over.over]p1: 4735 // [...] [Note: any redundant set of parentheses surrounding the 4736 // overloaded function name is ignored (5.1). ] 4737 Expr *OvlExpr = From->IgnoreParens(); 4738 4739 // C++ [over.over]p1: 4740 // [...] The overloaded function name can be preceded by the & 4741 // operator. 4742 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(OvlExpr)) { 4743 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 4744 OvlExpr = UnOp->getSubExpr()->IgnoreParens(); 4745 } 4746 4747 bool HasExplicitTemplateArgs = false; 4748 TemplateArgumentListInfo ExplicitTemplateArgs; 4749 4750 llvm::SmallVector<NamedDecl*,8> Fns; 4751 4752 // Look into the overloaded expression. 4753 if (UnresolvedLookupExpr *UL 4754 = dyn_cast<UnresolvedLookupExpr>(OvlExpr)) { 4755 Fns.append(UL->decls_begin(), UL->decls_end()); 4756 if (UL->hasExplicitTemplateArgs()) { 4757 HasExplicitTemplateArgs = true; 4758 UL->copyTemplateArgumentsInto(ExplicitTemplateArgs); 4759 } 4760 } else if (UnresolvedMemberExpr *ME 4761 = dyn_cast<UnresolvedMemberExpr>(OvlExpr)) { 4762 Fns.append(ME->decls_begin(), ME->decls_end()); 4763 if (ME->hasExplicitTemplateArgs()) { 4764 HasExplicitTemplateArgs = true; 4765 ME->copyTemplateArgumentsInto(ExplicitTemplateArgs); 4766 } 4767 } 4768 4769 // If we didn't actually find any template-ids, we're done. 4770 if (Fns.empty() || !HasExplicitTemplateArgs) 4771 return 0; 4772 4773 // Look through all of the overloaded functions, searching for one 4774 // whose type matches exactly. 4775 FunctionDecl *Matched = 0; 4776 for (llvm::SmallVectorImpl<NamedDecl*>::iterator I = Fns.begin(), 4777 E = Fns.end(); I != E; ++I) { 4778 // C++0x [temp.arg.explicit]p3: 4779 // [...] In contexts where deduction is done and fails, or in contexts 4780 // where deduction is not done, if a template argument list is 4781 // specified and it, along with any default template arguments, 4782 // identifies a single function template specialization, then the 4783 // template-id is an lvalue for the function template specialization. 4784 FunctionTemplateDecl *FunctionTemplate = cast<FunctionTemplateDecl>(*I); 4785 4786 // C++ [over.over]p2: 4787 // If the name is a function template, template argument deduction is 4788 // done (14.8.2.2), and if the argument deduction succeeds, the 4789 // resulting template argument list is used to generate a single 4790 // function template specialization, which is added to the set of 4791 // overloaded functions considered. 4792 // FIXME: We don't really want to build the specialization here, do we? 4793 FunctionDecl *Specialization = 0; 4794 TemplateDeductionInfo Info(Context); 4795 if (TemplateDeductionResult Result 4796 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs, 4797 Specialization, Info)) { 4798 // FIXME: make a note of the failed deduction for diagnostics. 4799 (void)Result; 4800 continue; 4801 } 4802 4803 // Multiple matches; we can't resolve to a single declaration. 4804 if (Matched) 4805 return 0; 4806 4807 Matched = Specialization; 4808 } 4809 4810 return Matched; 4811} 4812 4813/// \brief Add a single candidate to the overload set. 4814static void AddOverloadedCallCandidate(Sema &S, 4815 NamedDecl *Callee, 4816 const TemplateArgumentListInfo *ExplicitTemplateArgs, 4817 Expr **Args, unsigned NumArgs, 4818 OverloadCandidateSet &CandidateSet, 4819 bool PartialOverloading) { 4820 if (isa<UsingShadowDecl>(Callee)) 4821 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl(); 4822 4823 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) { 4824 assert(!ExplicitTemplateArgs && "Explicit template arguments?"); 4825 S.AddOverloadCandidate(Func, Args, NumArgs, CandidateSet, false, false, 4826 PartialOverloading); 4827 return; 4828 } 4829 4830 if (FunctionTemplateDecl *FuncTemplate 4831 = dyn_cast<FunctionTemplateDecl>(Callee)) { 4832 S.AddTemplateOverloadCandidate(FuncTemplate, ExplicitTemplateArgs, 4833 Args, NumArgs, CandidateSet); 4834 return; 4835 } 4836 4837 assert(false && "unhandled case in overloaded call candidate"); 4838 4839 // do nothing? 4840} 4841 4842/// \brief Add the overload candidates named by callee and/or found by argument 4843/// dependent lookup to the given overload set. 4844void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE, 4845 Expr **Args, unsigned NumArgs, 4846 OverloadCandidateSet &CandidateSet, 4847 bool PartialOverloading) { 4848 4849#ifndef NDEBUG 4850 // Verify that ArgumentDependentLookup is consistent with the rules 4851 // in C++0x [basic.lookup.argdep]p3: 4852 // 4853 // Let X be the lookup set produced by unqualified lookup (3.4.1) 4854 // and let Y be the lookup set produced by argument dependent 4855 // lookup (defined as follows). If X contains 4856 // 4857 // -- a declaration of a class member, or 4858 // 4859 // -- a block-scope function declaration that is not a 4860 // using-declaration, or 4861 // 4862 // -- a declaration that is neither a function or a function 4863 // template 4864 // 4865 // then Y is empty. 4866 4867 if (ULE->requiresADL()) { 4868 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 4869 E = ULE->decls_end(); I != E; ++I) { 4870 assert(!(*I)->getDeclContext()->isRecord()); 4871 assert(isa<UsingShadowDecl>(*I) || 4872 !(*I)->getDeclContext()->isFunctionOrMethod()); 4873 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate()); 4874 } 4875 } 4876#endif 4877 4878 // It would be nice to avoid this copy. 4879 TemplateArgumentListInfo TABuffer; 4880 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 4881 if (ULE->hasExplicitTemplateArgs()) { 4882 ULE->copyTemplateArgumentsInto(TABuffer); 4883 ExplicitTemplateArgs = &TABuffer; 4884 } 4885 4886 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(), 4887 E = ULE->decls_end(); I != E; ++I) 4888 AddOverloadedCallCandidate(*this, *I, ExplicitTemplateArgs, 4889 Args, NumArgs, CandidateSet, 4890 PartialOverloading); 4891 4892 if (ULE->requiresADL()) 4893 AddArgumentDependentLookupCandidates(ULE->getName(), Args, NumArgs, 4894 ExplicitTemplateArgs, 4895 CandidateSet, 4896 PartialOverloading); 4897} 4898 4899static Sema::OwningExprResult Destroy(Sema &SemaRef, Expr *Fn, 4900 Expr **Args, unsigned NumArgs) { 4901 Fn->Destroy(SemaRef.Context); 4902 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 4903 Args[Arg]->Destroy(SemaRef.Context); 4904 return SemaRef.ExprError(); 4905} 4906 4907/// Attempts to recover from a call where no functions were found. 4908/// 4909/// Returns true if new candidates were found. 4910static Sema::OwningExprResult 4911BuildRecoveryCallExpr(Sema &SemaRef, Expr *Fn, 4912 UnresolvedLookupExpr *ULE, 4913 SourceLocation LParenLoc, 4914 Expr **Args, unsigned NumArgs, 4915 SourceLocation *CommaLocs, 4916 SourceLocation RParenLoc) { 4917 4918 CXXScopeSpec SS; 4919 if (ULE->getQualifier()) { 4920 SS.setScopeRep(ULE->getQualifier()); 4921 SS.setRange(ULE->getQualifierRange()); 4922 } 4923 4924 TemplateArgumentListInfo TABuffer; 4925 const TemplateArgumentListInfo *ExplicitTemplateArgs = 0; 4926 if (ULE->hasExplicitTemplateArgs()) { 4927 ULE->copyTemplateArgumentsInto(TABuffer); 4928 ExplicitTemplateArgs = &TABuffer; 4929 } 4930 4931 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(), 4932 Sema::LookupOrdinaryName); 4933 if (SemaRef.DiagnoseEmptyLookup(/*Scope=*/0, SS, R)) 4934 return Destroy(SemaRef, Fn, Args, NumArgs); 4935 4936 assert(!R.empty() && "lookup results empty despite recovery"); 4937 4938 // Build an implicit member call if appropriate. Just drop the 4939 // casts and such from the call, we don't really care. 4940 Sema::OwningExprResult NewFn = SemaRef.ExprError(); 4941 if ((*R.begin())->isCXXClassMember()) 4942 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, R, ExplicitTemplateArgs); 4943 else if (ExplicitTemplateArgs) 4944 NewFn = SemaRef.BuildTemplateIdExpr(SS, R, false, *ExplicitTemplateArgs); 4945 else 4946 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false); 4947 4948 if (NewFn.isInvalid()) 4949 return Destroy(SemaRef, Fn, Args, NumArgs); 4950 4951 Fn->Destroy(SemaRef.Context); 4952 4953 // This shouldn't cause an infinite loop because we're giving it 4954 // an expression with non-empty lookup results, which should never 4955 // end up here. 4956 return SemaRef.ActOnCallExpr(/*Scope*/ 0, move(NewFn), LParenLoc, 4957 Sema::MultiExprArg(SemaRef, (void**) Args, NumArgs), 4958 CommaLocs, RParenLoc); 4959} 4960 4961/// ResolveOverloadedCallFn - Given the call expression that calls Fn 4962/// (which eventually refers to the declaration Func) and the call 4963/// arguments Args/NumArgs, attempt to resolve the function call down 4964/// to a specific function. If overload resolution succeeds, returns 4965/// the function declaration produced by overload 4966/// resolution. Otherwise, emits diagnostics, deletes all of the 4967/// arguments and Fn, and returns NULL. 4968Sema::OwningExprResult 4969Sema::BuildOverloadedCallExpr(Expr *Fn, UnresolvedLookupExpr *ULE, 4970 SourceLocation LParenLoc, 4971 Expr **Args, unsigned NumArgs, 4972 SourceLocation *CommaLocs, 4973 SourceLocation RParenLoc) { 4974#ifndef NDEBUG 4975 if (ULE->requiresADL()) { 4976 // To do ADL, we must have found an unqualified name. 4977 assert(!ULE->getQualifier() && "qualified name with ADL"); 4978 4979 // We don't perform ADL for implicit declarations of builtins. 4980 // Verify that this was correctly set up. 4981 FunctionDecl *F; 4982 if (ULE->decls_begin() + 1 == ULE->decls_end() && 4983 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) && 4984 F->getBuiltinID() && F->isImplicit()) 4985 assert(0 && "performing ADL for builtin"); 4986 4987 // We don't perform ADL in C. 4988 assert(getLangOptions().CPlusPlus && "ADL enabled in C"); 4989 } 4990#endif 4991 4992 OverloadCandidateSet CandidateSet; 4993 4994 // Add the functions denoted by the callee to the set of candidate 4995 // functions, including those from argument-dependent lookup. 4996 AddOverloadedCallCandidates(ULE, Args, NumArgs, CandidateSet); 4997 4998 // If we found nothing, try to recover. 4999 // AddRecoveryCallCandidates diagnoses the error itself, so we just 5000 // bailout out if it fails. 5001 if (CandidateSet.empty()) 5002 return BuildRecoveryCallExpr(*this, Fn, ULE, LParenLoc, Args, NumArgs, 5003 CommaLocs, RParenLoc); 5004 5005 OverloadCandidateSet::iterator Best; 5006 switch (BestViableFunction(CandidateSet, Fn->getLocStart(), Best)) { 5007 case OR_Success: { 5008 FunctionDecl *FDecl = Best->Function; 5009 Fn = FixOverloadedFunctionReference(Fn, FDecl); 5010 return BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, NumArgs, RParenLoc); 5011 } 5012 5013 case OR_No_Viable_Function: 5014 Diag(Fn->getSourceRange().getBegin(), 5015 diag::err_ovl_no_viable_function_in_call) 5016 << ULE->getName() << Fn->getSourceRange(); 5017 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5018 break; 5019 5020 case OR_Ambiguous: 5021 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 5022 << ULE->getName() << Fn->getSourceRange(); 5023 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates); 5024 break; 5025 5026 case OR_Deleted: 5027 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 5028 << Best->Function->isDeleted() 5029 << ULE->getName() 5030 << Fn->getSourceRange(); 5031 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5032 break; 5033 } 5034 5035 // Overload resolution failed. Destroy all of the subexpressions and 5036 // return NULL. 5037 Fn->Destroy(Context); 5038 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 5039 Args[Arg]->Destroy(Context); 5040 return ExprError(); 5041} 5042 5043static bool IsOverloaded(const Sema::FunctionSet &Functions) { 5044 return Functions.size() > 1 || 5045 (Functions.size() == 1 && isa<FunctionTemplateDecl>(*Functions.begin())); 5046} 5047 5048/// \brief Create a unary operation that may resolve to an overloaded 5049/// operator. 5050/// 5051/// \param OpLoc The location of the operator itself (e.g., '*'). 5052/// 5053/// \param OpcIn The UnaryOperator::Opcode that describes this 5054/// operator. 5055/// 5056/// \param Functions The set of non-member functions that will be 5057/// considered by overload resolution. The caller needs to build this 5058/// set based on the context using, e.g., 5059/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5060/// set should not contain any member functions; those will be added 5061/// by CreateOverloadedUnaryOp(). 5062/// 5063/// \param input The input argument. 5064Sema::OwningExprResult Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, 5065 unsigned OpcIn, 5066 FunctionSet &Functions, 5067 ExprArg input) { 5068 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 5069 Expr *Input = (Expr *)input.get(); 5070 5071 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 5072 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 5073 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5074 5075 Expr *Args[2] = { Input, 0 }; 5076 unsigned NumArgs = 1; 5077 5078 // For post-increment and post-decrement, add the implicit '0' as 5079 // the second argument, so that we know this is a post-increment or 5080 // post-decrement. 5081 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 5082 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 5083 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 5084 SourceLocation()); 5085 NumArgs = 2; 5086 } 5087 5088 if (Input->isTypeDependent()) { 5089 UnresolvedLookupExpr *Fn 5090 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, 5091 0, SourceRange(), OpName, OpLoc, 5092 /*ADL*/ true, IsOverloaded(Functions)); 5093 for (FunctionSet::iterator Func = Functions.begin(), 5094 FuncEnd = Functions.end(); 5095 Func != FuncEnd; ++Func) 5096 Fn->addDecl(*Func); 5097 5098 input.release(); 5099 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 5100 &Args[0], NumArgs, 5101 Context.DependentTy, 5102 OpLoc)); 5103 } 5104 5105 // Build an empty overload set. 5106 OverloadCandidateSet CandidateSet; 5107 5108 // Add the candidates from the given function set. 5109 AddFunctionCandidates(Functions, &Args[0], NumArgs, CandidateSet, false); 5110 5111 // Add operator candidates that are member functions. 5112 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5113 5114 // Add builtin operator candidates. 5115 AddBuiltinOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 5116 5117 // Perform overload resolution. 5118 OverloadCandidateSet::iterator Best; 5119 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5120 case OR_Success: { 5121 // We found a built-in operator or an overloaded operator. 5122 FunctionDecl *FnDecl = Best->Function; 5123 5124 if (FnDecl) { 5125 // We matched an overloaded operator. Build a call to that 5126 // operator. 5127 5128 // Convert the arguments. 5129 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 5130 if (PerformObjectArgumentInitialization(Input, Method)) 5131 return ExprError(); 5132 } else { 5133 // Convert the arguments. 5134 OwningExprResult InputInit 5135 = PerformCopyInitialization(InitializedEntity::InitializeParameter( 5136 FnDecl->getParamDecl(0)), 5137 SourceLocation(), 5138 move(input)); 5139 if (InputInit.isInvalid()) 5140 return ExprError(); 5141 5142 input = move(InputInit); 5143 Input = (Expr *)input.get(); 5144 } 5145 5146 // Determine the result type 5147 QualType ResultTy = FnDecl->getResultType().getNonReferenceType(); 5148 5149 // Build the actual expression node. 5150 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5151 SourceLocation()); 5152 UsualUnaryConversions(FnExpr); 5153 5154 input.release(); 5155 Args[0] = Input; 5156 ExprOwningPtr<CallExpr> TheCall(this, 5157 new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 5158 Args, NumArgs, ResultTy, OpLoc)); 5159 5160 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 5161 FnDecl)) 5162 return ExprError(); 5163 5164 return MaybeBindToTemporary(TheCall.release()); 5165 } else { 5166 // We matched a built-in operator. Convert the arguments, then 5167 // break out so that we will build the appropriate built-in 5168 // operator node. 5169 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 5170 Best->Conversions[0], AA_Passing)) 5171 return ExprError(); 5172 5173 break; 5174 } 5175 } 5176 5177 case OR_No_Viable_Function: 5178 // No viable function; fall through to handling this as a 5179 // built-in operator, which will produce an error message for us. 5180 break; 5181 5182 case OR_Ambiguous: 5183 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5184 << UnaryOperator::getOpcodeStr(Opc) 5185 << Input->getSourceRange(); 5186 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, 5187 UnaryOperator::getOpcodeStr(Opc), OpLoc); 5188 return ExprError(); 5189 5190 case OR_Deleted: 5191 Diag(OpLoc, diag::err_ovl_deleted_oper) 5192 << Best->Function->isDeleted() 5193 << UnaryOperator::getOpcodeStr(Opc) 5194 << Input->getSourceRange(); 5195 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5196 return ExprError(); 5197 } 5198 5199 // Either we found no viable overloaded operator or we matched a 5200 // built-in operator. In either case, fall through to trying to 5201 // build a built-in operation. 5202 input.release(); 5203 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 5204} 5205 5206/// \brief Create a binary operation that may resolve to an overloaded 5207/// operator. 5208/// 5209/// \param OpLoc The location of the operator itself (e.g., '+'). 5210/// 5211/// \param OpcIn The BinaryOperator::Opcode that describes this 5212/// operator. 5213/// 5214/// \param Functions The set of non-member functions that will be 5215/// considered by overload resolution. The caller needs to build this 5216/// set based on the context using, e.g., 5217/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 5218/// set should not contain any member functions; those will be added 5219/// by CreateOverloadedBinOp(). 5220/// 5221/// \param LHS Left-hand argument. 5222/// \param RHS Right-hand argument. 5223Sema::OwningExprResult 5224Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 5225 unsigned OpcIn, 5226 FunctionSet &Functions, 5227 Expr *LHS, Expr *RHS) { 5228 Expr *Args[2] = { LHS, RHS }; 5229 LHS=RHS=0; //Please use only Args instead of LHS/RHS couple 5230 5231 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 5232 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 5233 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 5234 5235 // If either side is type-dependent, create an appropriate dependent 5236 // expression. 5237 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 5238 if (Functions.empty()) { 5239 // If there are no functions to store, just build a dependent 5240 // BinaryOperator or CompoundAssignment. 5241 if (Opc <= BinaryOperator::Assign || Opc > BinaryOperator::OrAssign) 5242 return Owned(new (Context) BinaryOperator(Args[0], Args[1], Opc, 5243 Context.DependentTy, OpLoc)); 5244 5245 return Owned(new (Context) CompoundAssignOperator(Args[0], Args[1], Opc, 5246 Context.DependentTy, 5247 Context.DependentTy, 5248 Context.DependentTy, 5249 OpLoc)); 5250 } 5251 5252 UnresolvedLookupExpr *Fn 5253 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, 5254 0, SourceRange(), OpName, OpLoc, 5255 /* ADL */ true, IsOverloaded(Functions)); 5256 5257 for (FunctionSet::iterator Func = Functions.begin(), 5258 FuncEnd = Functions.end(); 5259 Func != FuncEnd; ++Func) 5260 Fn->addDecl(*Func); 5261 5262 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 5263 Args, 2, 5264 Context.DependentTy, 5265 OpLoc)); 5266 } 5267 5268 // If this is the .* operator, which is not overloadable, just 5269 // create a built-in binary operator. 5270 if (Opc == BinaryOperator::PtrMemD) 5271 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 5272 5273 // If this is the assignment operator, we only perform overload resolution 5274 // if the left-hand side is a class or enumeration type. This is actually 5275 // a hack. The standard requires that we do overload resolution between the 5276 // various built-in candidates, but as DR507 points out, this can lead to 5277 // problems. So we do it this way, which pretty much follows what GCC does. 5278 // Note that we go the traditional code path for compound assignment forms. 5279 if (Opc==BinaryOperator::Assign && !Args[0]->getType()->isOverloadableType()) 5280 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 5281 5282 // Build an empty overload set. 5283 OverloadCandidateSet CandidateSet; 5284 5285 // Add the candidates from the given function set. 5286 AddFunctionCandidates(Functions, Args, 2, CandidateSet, false); 5287 5288 // Add operator candidates that are member functions. 5289 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 5290 5291 // Add builtin operator candidates. 5292 AddBuiltinOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 5293 5294 // Perform overload resolution. 5295 OverloadCandidateSet::iterator Best; 5296 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5297 case OR_Success: { 5298 // We found a built-in operator or an overloaded operator. 5299 FunctionDecl *FnDecl = Best->Function; 5300 5301 if (FnDecl) { 5302 // We matched an overloaded operator. Build a call to that 5303 // operator. 5304 5305 // Convert the arguments. 5306 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 5307 OwningExprResult Arg1 5308 = PerformCopyInitialization( 5309 InitializedEntity::InitializeParameter( 5310 FnDecl->getParamDecl(0)), 5311 SourceLocation(), 5312 Owned(Args[1])); 5313 if (Arg1.isInvalid()) 5314 return ExprError(); 5315 5316 if (PerformObjectArgumentInitialization(Args[0], Method)) 5317 return ExprError(); 5318 5319 Args[1] = RHS = Arg1.takeAs<Expr>(); 5320 } else { 5321 // Convert the arguments. 5322 OwningExprResult Arg0 5323 = PerformCopyInitialization( 5324 InitializedEntity::InitializeParameter( 5325 FnDecl->getParamDecl(0)), 5326 SourceLocation(), 5327 Owned(Args[0])); 5328 if (Arg0.isInvalid()) 5329 return ExprError(); 5330 5331 OwningExprResult Arg1 5332 = PerformCopyInitialization( 5333 InitializedEntity::InitializeParameter( 5334 FnDecl->getParamDecl(1)), 5335 SourceLocation(), 5336 Owned(Args[1])); 5337 if (Arg1.isInvalid()) 5338 return ExprError(); 5339 Args[0] = LHS = Arg0.takeAs<Expr>(); 5340 Args[1] = RHS = Arg1.takeAs<Expr>(); 5341 } 5342 5343 // Determine the result type 5344 QualType ResultTy 5345 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 5346 ResultTy = ResultTy.getNonReferenceType(); 5347 5348 // Build the actual expression node. 5349 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5350 OpLoc); 5351 UsualUnaryConversions(FnExpr); 5352 5353 ExprOwningPtr<CXXOperatorCallExpr> 5354 TheCall(this, new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 5355 Args, 2, ResultTy, 5356 OpLoc)); 5357 5358 if (CheckCallReturnType(FnDecl->getResultType(), OpLoc, TheCall.get(), 5359 FnDecl)) 5360 return ExprError(); 5361 5362 return MaybeBindToTemporary(TheCall.release()); 5363 } else { 5364 // We matched a built-in operator. Convert the arguments, then 5365 // break out so that we will build the appropriate built-in 5366 // operator node. 5367 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 5368 Best->Conversions[0], AA_Passing) || 5369 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 5370 Best->Conversions[1], AA_Passing)) 5371 return ExprError(); 5372 5373 break; 5374 } 5375 } 5376 5377 case OR_No_Viable_Function: { 5378 // C++ [over.match.oper]p9: 5379 // If the operator is the operator , [...] and there are no 5380 // viable functions, then the operator is assumed to be the 5381 // built-in operator and interpreted according to clause 5. 5382 if (Opc == BinaryOperator::Comma) 5383 break; 5384 5385 // For class as left operand for assignment or compound assigment operator 5386 // do not fall through to handling in built-in, but report that no overloaded 5387 // assignment operator found 5388 OwningExprResult Result = ExprError(); 5389 if (Args[0]->getType()->isRecordType() && 5390 Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign) { 5391 Diag(OpLoc, diag::err_ovl_no_viable_oper) 5392 << BinaryOperator::getOpcodeStr(Opc) 5393 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5394 } else { 5395 // No viable function; try to create a built-in operation, which will 5396 // produce an error. Then, show the non-viable candidates. 5397 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 5398 } 5399 assert(Result.isInvalid() && 5400 "C++ binary operator overloading is missing candidates!"); 5401 if (Result.isInvalid()) 5402 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, 5403 BinaryOperator::getOpcodeStr(Opc), OpLoc); 5404 return move(Result); 5405 } 5406 5407 case OR_Ambiguous: 5408 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5409 << BinaryOperator::getOpcodeStr(Opc) 5410 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5411 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, 5412 BinaryOperator::getOpcodeStr(Opc), OpLoc); 5413 return ExprError(); 5414 5415 case OR_Deleted: 5416 Diag(OpLoc, diag::err_ovl_deleted_oper) 5417 << Best->Function->isDeleted() 5418 << BinaryOperator::getOpcodeStr(Opc) 5419 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5420 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5421 return ExprError(); 5422 } 5423 5424 // We matched a built-in operator; build it. 5425 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]); 5426} 5427 5428Action::OwningExprResult 5429Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc, 5430 SourceLocation RLoc, 5431 ExprArg Base, ExprArg Idx) { 5432 Expr *Args[2] = { static_cast<Expr*>(Base.get()), 5433 static_cast<Expr*>(Idx.get()) }; 5434 DeclarationName OpName = 5435 Context.DeclarationNames.getCXXOperatorName(OO_Subscript); 5436 5437 // If either side is type-dependent, create an appropriate dependent 5438 // expression. 5439 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) { 5440 5441 UnresolvedLookupExpr *Fn 5442 = UnresolvedLookupExpr::Create(Context, /*Dependent*/ true, 5443 0, SourceRange(), OpName, LLoc, 5444 /*ADL*/ true, /*Overloaded*/ false); 5445 // Can't add any actual overloads yet 5446 5447 Base.release(); 5448 Idx.release(); 5449 return Owned(new (Context) CXXOperatorCallExpr(Context, OO_Subscript, Fn, 5450 Args, 2, 5451 Context.DependentTy, 5452 RLoc)); 5453 } 5454 5455 // Build an empty overload set. 5456 OverloadCandidateSet CandidateSet; 5457 5458 // Subscript can only be overloaded as a member function. 5459 5460 // Add operator candidates that are member functions. 5461 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 5462 5463 // Add builtin operator candidates. 5464 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, 2, CandidateSet); 5465 5466 // Perform overload resolution. 5467 OverloadCandidateSet::iterator Best; 5468 switch (BestViableFunction(CandidateSet, LLoc, Best)) { 5469 case OR_Success: { 5470 // We found a built-in operator or an overloaded operator. 5471 FunctionDecl *FnDecl = Best->Function; 5472 5473 if (FnDecl) { 5474 // We matched an overloaded operator. Build a call to that 5475 // operator. 5476 5477 // Convert the arguments. 5478 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl); 5479 if (PerformObjectArgumentInitialization(Args[0], Method) || 5480 PerformCopyInitialization(Args[1], 5481 FnDecl->getParamDecl(0)->getType(), 5482 AA_Passing)) 5483 return ExprError(); 5484 5485 // Determine the result type 5486 QualType ResultTy 5487 = FnDecl->getType()->getAs<FunctionType>()->getResultType(); 5488 ResultTy = ResultTy.getNonReferenceType(); 5489 5490 // Build the actual expression node. 5491 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 5492 LLoc); 5493 UsualUnaryConversions(FnExpr); 5494 5495 Base.release(); 5496 Idx.release(); 5497 ExprOwningPtr<CXXOperatorCallExpr> 5498 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Subscript, 5499 FnExpr, Args, 2, 5500 ResultTy, RLoc)); 5501 5502 if (CheckCallReturnType(FnDecl->getResultType(), LLoc, TheCall.get(), 5503 FnDecl)) 5504 return ExprError(); 5505 5506 return MaybeBindToTemporary(TheCall.release()); 5507 } else { 5508 // We matched a built-in operator. Convert the arguments, then 5509 // break out so that we will build the appropriate built-in 5510 // operator node. 5511 if (PerformImplicitConversion(Args[0], Best->BuiltinTypes.ParamTypes[0], 5512 Best->Conversions[0], AA_Passing) || 5513 PerformImplicitConversion(Args[1], Best->BuiltinTypes.ParamTypes[1], 5514 Best->Conversions[1], AA_Passing)) 5515 return ExprError(); 5516 5517 break; 5518 } 5519 } 5520 5521 case OR_No_Viable_Function: { 5522 if (CandidateSet.empty()) 5523 Diag(LLoc, diag::err_ovl_no_oper) 5524 << Args[0]->getType() << /*subscript*/ 0 5525 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5526 else 5527 Diag(LLoc, diag::err_ovl_no_viable_subscript) 5528 << Args[0]->getType() 5529 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5530 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, 5531 "[]", LLoc); 5532 return ExprError(); 5533 } 5534 5535 case OR_Ambiguous: 5536 Diag(LLoc, diag::err_ovl_ambiguous_oper) 5537 << "[]" << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5538 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates, 5539 "[]", LLoc); 5540 return ExprError(); 5541 5542 case OR_Deleted: 5543 Diag(LLoc, diag::err_ovl_deleted_oper) 5544 << Best->Function->isDeleted() << "[]" 5545 << Args[0]->getSourceRange() << Args[1]->getSourceRange(); 5546 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates, 5547 "[]", LLoc); 5548 return ExprError(); 5549 } 5550 5551 // We matched a built-in operator; build it. 5552 Base.release(); 5553 Idx.release(); 5554 return CreateBuiltinArraySubscriptExpr(Owned(Args[0]), LLoc, 5555 Owned(Args[1]), RLoc); 5556} 5557 5558/// BuildCallToMemberFunction - Build a call to a member 5559/// function. MemExpr is the expression that refers to the member 5560/// function (and includes the object parameter), Args/NumArgs are the 5561/// arguments to the function call (not including the object 5562/// parameter). The caller needs to validate that the member 5563/// expression refers to a member function or an overloaded member 5564/// function. 5565Sema::OwningExprResult 5566Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 5567 SourceLocation LParenLoc, Expr **Args, 5568 unsigned NumArgs, SourceLocation *CommaLocs, 5569 SourceLocation RParenLoc) { 5570 // Dig out the member expression. This holds both the object 5571 // argument and the member function we're referring to. 5572 Expr *NakedMemExpr = MemExprE->IgnoreParens(); 5573 5574 MemberExpr *MemExpr; 5575 CXXMethodDecl *Method = 0; 5576 if (isa<MemberExpr>(NakedMemExpr)) { 5577 MemExpr = cast<MemberExpr>(NakedMemExpr); 5578 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 5579 } else { 5580 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr); 5581 5582 QualType ObjectType = UnresExpr->getBaseType(); 5583 5584 // Add overload candidates 5585 OverloadCandidateSet CandidateSet; 5586 5587 // FIXME: avoid copy. 5588 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 5589 if (UnresExpr->hasExplicitTemplateArgs()) { 5590 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 5591 TemplateArgs = &TemplateArgsBuffer; 5592 } 5593 5594 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(), 5595 E = UnresExpr->decls_end(); I != E; ++I) { 5596 5597 NamedDecl *Func = *I; 5598 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext()); 5599 if (isa<UsingShadowDecl>(Func)) 5600 Func = cast<UsingShadowDecl>(Func)->getTargetDecl(); 5601 5602 if ((Method = dyn_cast<CXXMethodDecl>(Func))) { 5603 // If explicit template arguments were provided, we can't call a 5604 // non-template member function. 5605 if (TemplateArgs) 5606 continue; 5607 5608 AddMethodCandidate(Method, ActingDC, ObjectType, Args, NumArgs, 5609 CandidateSet, /*SuppressUserConversions=*/false); 5610 } else { 5611 AddMethodTemplateCandidate(cast<FunctionTemplateDecl>(Func), 5612 ActingDC, TemplateArgs, 5613 ObjectType, Args, NumArgs, 5614 CandidateSet, 5615 /*SuppressUsedConversions=*/false); 5616 } 5617 } 5618 5619 DeclarationName DeclName = UnresExpr->getMemberName(); 5620 5621 OverloadCandidateSet::iterator Best; 5622 switch (BestViableFunction(CandidateSet, UnresExpr->getLocStart(), Best)) { 5623 case OR_Success: 5624 Method = cast<CXXMethodDecl>(Best->Function); 5625 break; 5626 5627 case OR_No_Viable_Function: 5628 Diag(UnresExpr->getMemberLoc(), 5629 diag::err_ovl_no_viable_member_function_in_call) 5630 << DeclName << MemExprE->getSourceRange(); 5631 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5632 // FIXME: Leaking incoming expressions! 5633 return ExprError(); 5634 5635 case OR_Ambiguous: 5636 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_ambiguous_member_call) 5637 << DeclName << MemExprE->getSourceRange(); 5638 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5639 // FIXME: Leaking incoming expressions! 5640 return ExprError(); 5641 5642 case OR_Deleted: 5643 Diag(UnresExpr->getMemberLoc(), diag::err_ovl_deleted_member_call) 5644 << Best->Function->isDeleted() 5645 << DeclName << MemExprE->getSourceRange(); 5646 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5647 // FIXME: Leaking incoming expressions! 5648 return ExprError(); 5649 } 5650 5651 MemExprE = FixOverloadedFunctionReference(MemExprE, Method); 5652 5653 // If overload resolution picked a static member, build a 5654 // non-member call based on that function. 5655 if (Method->isStatic()) { 5656 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, 5657 Args, NumArgs, RParenLoc); 5658 } 5659 5660 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens()); 5661 } 5662 5663 assert(Method && "Member call to something that isn't a method?"); 5664 ExprOwningPtr<CXXMemberCallExpr> 5665 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExprE, Args, 5666 NumArgs, 5667 Method->getResultType().getNonReferenceType(), 5668 RParenLoc)); 5669 5670 // Check for a valid return type. 5671 if (CheckCallReturnType(Method->getResultType(), MemExpr->getMemberLoc(), 5672 TheCall.get(), Method)) 5673 return ExprError(); 5674 5675 // Convert the object argument (for a non-static member function call). 5676 Expr *ObjectArg = MemExpr->getBase(); 5677 if (!Method->isStatic() && 5678 PerformObjectArgumentInitialization(ObjectArg, Method)) 5679 return ExprError(); 5680 MemExpr->setBase(ObjectArg); 5681 5682 // Convert the rest of the arguments 5683 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 5684 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 5685 RParenLoc)) 5686 return ExprError(); 5687 5688 if (CheckFunctionCall(Method, TheCall.get())) 5689 return ExprError(); 5690 5691 return MaybeBindToTemporary(TheCall.release()); 5692} 5693 5694/// BuildCallToObjectOfClassType - Build a call to an object of class 5695/// type (C++ [over.call.object]), which can end up invoking an 5696/// overloaded function call operator (@c operator()) or performing a 5697/// user-defined conversion on the object argument. 5698Sema::ExprResult 5699Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 5700 SourceLocation LParenLoc, 5701 Expr **Args, unsigned NumArgs, 5702 SourceLocation *CommaLocs, 5703 SourceLocation RParenLoc) { 5704 assert(Object->getType()->isRecordType() && "Requires object type argument"); 5705 const RecordType *Record = Object->getType()->getAs<RecordType>(); 5706 5707 // C++ [over.call.object]p1: 5708 // If the primary-expression E in the function call syntax 5709 // evaluates to a class object of type "cv T", then the set of 5710 // candidate functions includes at least the function call 5711 // operators of T. The function call operators of T are obtained by 5712 // ordinary lookup of the name operator() in the context of 5713 // (E).operator(). 5714 OverloadCandidateSet CandidateSet; 5715 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 5716 5717 if (RequireCompleteType(LParenLoc, Object->getType(), 5718 PartialDiagnostic(diag::err_incomplete_object_call) 5719 << Object->getSourceRange())) 5720 return true; 5721 5722 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName); 5723 LookupQualifiedName(R, Record->getDecl()); 5724 R.suppressDiagnostics(); 5725 5726 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 5727 Oper != OperEnd; ++Oper) { 5728 AddMethodCandidate(*Oper, Object->getType(), Args, NumArgs, CandidateSet, 5729 /*SuppressUserConversions=*/ false); 5730 } 5731 5732 // C++ [over.call.object]p2: 5733 // In addition, for each conversion function declared in T of the 5734 // form 5735 // 5736 // operator conversion-type-id () cv-qualifier; 5737 // 5738 // where cv-qualifier is the same cv-qualification as, or a 5739 // greater cv-qualification than, cv, and where conversion-type-id 5740 // denotes the type "pointer to function of (P1,...,Pn) returning 5741 // R", or the type "reference to pointer to function of 5742 // (P1,...,Pn) returning R", or the type "reference to function 5743 // of (P1,...,Pn) returning R", a surrogate call function [...] 5744 // is also considered as a candidate function. Similarly, 5745 // surrogate call functions are added to the set of candidate 5746 // functions for each conversion function declared in an 5747 // accessible base class provided the function is not hidden 5748 // within T by another intervening declaration. 5749 // FIXME: Look in base classes for more conversion operators! 5750 const UnresolvedSet *Conversions 5751 = cast<CXXRecordDecl>(Record->getDecl())->getConversionFunctions(); 5752 for (UnresolvedSet::iterator I = Conversions->begin(), 5753 E = Conversions->end(); I != E; ++I) { 5754 NamedDecl *D = *I; 5755 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 5756 if (isa<UsingShadowDecl>(D)) 5757 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 5758 5759 // Skip over templated conversion functions; they aren't 5760 // surrogates. 5761 if (isa<FunctionTemplateDecl>(D)) 5762 continue; 5763 5764 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D); 5765 5766 // Strip the reference type (if any) and then the pointer type (if 5767 // any) to get down to what might be a function type. 5768 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 5769 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>()) 5770 ConvType = ConvPtrType->getPointeeType(); 5771 5772 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>()) 5773 AddSurrogateCandidate(Conv, ActingContext, Proto, 5774 Object->getType(), Args, NumArgs, 5775 CandidateSet); 5776 } 5777 5778 // Perform overload resolution. 5779 OverloadCandidateSet::iterator Best; 5780 switch (BestViableFunction(CandidateSet, Object->getLocStart(), Best)) { 5781 case OR_Success: 5782 // Overload resolution succeeded; we'll build the appropriate call 5783 // below. 5784 break; 5785 5786 case OR_No_Viable_Function: 5787 if (CandidateSet.empty()) 5788 Diag(Object->getSourceRange().getBegin(), diag::err_ovl_no_oper) 5789 << Object->getType() << /*call*/ 1 5790 << Object->getSourceRange(); 5791 else 5792 Diag(Object->getSourceRange().getBegin(), 5793 diag::err_ovl_no_viable_object_call) 5794 << Object->getType() << Object->getSourceRange(); 5795 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5796 break; 5797 5798 case OR_Ambiguous: 5799 Diag(Object->getSourceRange().getBegin(), 5800 diag::err_ovl_ambiguous_object_call) 5801 << Object->getType() << Object->getSourceRange(); 5802 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates); 5803 break; 5804 5805 case OR_Deleted: 5806 Diag(Object->getSourceRange().getBegin(), 5807 diag::err_ovl_deleted_object_call) 5808 << Best->Function->isDeleted() 5809 << Object->getType() << Object->getSourceRange(); 5810 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5811 break; 5812 } 5813 5814 if (Best == CandidateSet.end()) { 5815 // We had an error; delete all of the subexpressions and return 5816 // the error. 5817 Object->Destroy(Context); 5818 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 5819 Args[ArgIdx]->Destroy(Context); 5820 return true; 5821 } 5822 5823 if (Best->Function == 0) { 5824 // Since there is no function declaration, this is one of the 5825 // surrogate candidates. Dig out the conversion function. 5826 CXXConversionDecl *Conv 5827 = cast<CXXConversionDecl>( 5828 Best->Conversions[0].UserDefined.ConversionFunction); 5829 5830 // We selected one of the surrogate functions that converts the 5831 // object parameter to a function pointer. Perform the conversion 5832 // on the object argument, then let ActOnCallExpr finish the job. 5833 5834 // Create an implicit member expr to refer to the conversion operator. 5835 // and then call it. 5836 CXXMemberCallExpr *CE = BuildCXXMemberCallExpr(Object, Conv); 5837 5838 return ActOnCallExpr(S, ExprArg(*this, CE), LParenLoc, 5839 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 5840 CommaLocs, RParenLoc).release(); 5841 } 5842 5843 // We found an overloaded operator(). Build a CXXOperatorCallExpr 5844 // that calls this method, using Object for the implicit object 5845 // parameter and passing along the remaining arguments. 5846 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 5847 const FunctionProtoType *Proto = Method->getType()->getAs<FunctionProtoType>(); 5848 5849 unsigned NumArgsInProto = Proto->getNumArgs(); 5850 unsigned NumArgsToCheck = NumArgs; 5851 5852 // Build the full argument list for the method call (the 5853 // implicit object parameter is placed at the beginning of the 5854 // list). 5855 Expr **MethodArgs; 5856 if (NumArgs < NumArgsInProto) { 5857 NumArgsToCheck = NumArgsInProto; 5858 MethodArgs = new Expr*[NumArgsInProto + 1]; 5859 } else { 5860 MethodArgs = new Expr*[NumArgs + 1]; 5861 } 5862 MethodArgs[0] = Object; 5863 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 5864 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 5865 5866 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 5867 SourceLocation()); 5868 UsualUnaryConversions(NewFn); 5869 5870 // Once we've built TheCall, all of the expressions are properly 5871 // owned. 5872 QualType ResultTy = Method->getResultType().getNonReferenceType(); 5873 ExprOwningPtr<CXXOperatorCallExpr> 5874 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 5875 MethodArgs, NumArgs + 1, 5876 ResultTy, RParenLoc)); 5877 delete [] MethodArgs; 5878 5879 if (CheckCallReturnType(Method->getResultType(), LParenLoc, TheCall.get(), 5880 Method)) 5881 return true; 5882 5883 // We may have default arguments. If so, we need to allocate more 5884 // slots in the call for them. 5885 if (NumArgs < NumArgsInProto) 5886 TheCall->setNumArgs(Context, NumArgsInProto + 1); 5887 else if (NumArgs > NumArgsInProto) 5888 NumArgsToCheck = NumArgsInProto; 5889 5890 bool IsError = false; 5891 5892 // Initialize the implicit object parameter. 5893 IsError |= PerformObjectArgumentInitialization(Object, Method); 5894 TheCall->setArg(0, Object); 5895 5896 5897 // Check the argument types. 5898 for (unsigned i = 0; i != NumArgsToCheck; i++) { 5899 Expr *Arg; 5900 if (i < NumArgs) { 5901 Arg = Args[i]; 5902 5903 // Pass the argument. 5904 QualType ProtoArgType = Proto->getArgType(i); 5905 IsError |= PerformCopyInitialization(Arg, ProtoArgType, AA_Passing); 5906 } else { 5907 OwningExprResult DefArg 5908 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i)); 5909 if (DefArg.isInvalid()) { 5910 IsError = true; 5911 break; 5912 } 5913 5914 Arg = DefArg.takeAs<Expr>(); 5915 } 5916 5917 TheCall->setArg(i + 1, Arg); 5918 } 5919 5920 // If this is a variadic call, handle args passed through "...". 5921 if (Proto->isVariadic()) { 5922 // Promote the arguments (C99 6.5.2.2p7). 5923 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 5924 Expr *Arg = Args[i]; 5925 IsError |= DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 5926 TheCall->setArg(i + 1, Arg); 5927 } 5928 } 5929 5930 if (IsError) return true; 5931 5932 if (CheckFunctionCall(Method, TheCall.get())) 5933 return true; 5934 5935 return MaybeBindToTemporary(TheCall.release()).release(); 5936} 5937 5938/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 5939/// (if one exists), where @c Base is an expression of class type and 5940/// @c Member is the name of the member we're trying to find. 5941Sema::OwningExprResult 5942Sema::BuildOverloadedArrowExpr(Scope *S, ExprArg BaseIn, SourceLocation OpLoc) { 5943 Expr *Base = static_cast<Expr *>(BaseIn.get()); 5944 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 5945 5946 // C++ [over.ref]p1: 5947 // 5948 // [...] An expression x->m is interpreted as (x.operator->())->m 5949 // for a class object x of type T if T::operator->() exists and if 5950 // the operator is selected as the best match function by the 5951 // overload resolution mechanism (13.3). 5952 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 5953 OverloadCandidateSet CandidateSet; 5954 const RecordType *BaseRecord = Base->getType()->getAs<RecordType>(); 5955 5956 if (RequireCompleteType(Base->getLocStart(), Base->getType(), 5957 PDiag(diag::err_typecheck_incomplete_tag) 5958 << Base->getSourceRange())) 5959 return ExprError(); 5960 5961 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName); 5962 LookupQualifiedName(R, BaseRecord->getDecl()); 5963 R.suppressDiagnostics(); 5964 5965 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end(); 5966 Oper != OperEnd; ++Oper) { 5967 NamedDecl *D = *Oper; 5968 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext()); 5969 if (isa<UsingShadowDecl>(D)) 5970 D = cast<UsingShadowDecl>(D)->getTargetDecl(); 5971 5972 AddMethodCandidate(cast<CXXMethodDecl>(D), ActingContext, 5973 Base->getType(), 0, 0, CandidateSet, 5974 /*SuppressUserConversions=*/false); 5975 } 5976 5977 // Perform overload resolution. 5978 OverloadCandidateSet::iterator Best; 5979 switch (BestViableFunction(CandidateSet, OpLoc, Best)) { 5980 case OR_Success: 5981 // Overload resolution succeeded; we'll build the call below. 5982 break; 5983 5984 case OR_No_Viable_Function: 5985 if (CandidateSet.empty()) 5986 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 5987 << Base->getType() << Base->getSourceRange(); 5988 else 5989 Diag(OpLoc, diag::err_ovl_no_viable_oper) 5990 << "operator->" << Base->getSourceRange(); 5991 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 5992 return ExprError(); 5993 5994 case OR_Ambiguous: 5995 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 5996 << "->" << Base->getSourceRange(); 5997 PrintOverloadCandidates(CandidateSet, OCD_ViableCandidates); 5998 return ExprError(); 5999 6000 case OR_Deleted: 6001 Diag(OpLoc, diag::err_ovl_deleted_oper) 6002 << Best->Function->isDeleted() 6003 << "->" << Base->getSourceRange(); 6004 PrintOverloadCandidates(CandidateSet, OCD_AllCandidates); 6005 return ExprError(); 6006 } 6007 6008 // Convert the object parameter. 6009 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 6010 if (PerformObjectArgumentInitialization(Base, Method)) 6011 return ExprError(); 6012 6013 // No concerns about early exits now. 6014 BaseIn.release(); 6015 6016 // Build the operator call. 6017 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 6018 SourceLocation()); 6019 UsualUnaryConversions(FnExpr); 6020 6021 QualType ResultTy = Method->getResultType().getNonReferenceType(); 6022 ExprOwningPtr<CXXOperatorCallExpr> 6023 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, 6024 &Base, 1, ResultTy, OpLoc)); 6025 6026 if (CheckCallReturnType(Method->getResultType(), OpLoc, TheCall.get(), 6027 Method)) 6028 return ExprError(); 6029 return move(TheCall); 6030} 6031 6032/// FixOverloadedFunctionReference - E is an expression that refers to 6033/// a C++ overloaded function (possibly with some parentheses and 6034/// perhaps a '&' around it). We have resolved the overloaded function 6035/// to the function declaration Fn, so patch up the expression E to 6036/// refer (possibly indirectly) to Fn. Returns the new expr. 6037Expr *Sema::FixOverloadedFunctionReference(Expr *E, FunctionDecl *Fn) { 6038 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 6039 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(), Fn); 6040 if (SubExpr == PE->getSubExpr()) 6041 return PE->Retain(); 6042 6043 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr); 6044 } 6045 6046 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) { 6047 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(), Fn); 6048 assert(Context.hasSameType(ICE->getSubExpr()->getType(), 6049 SubExpr->getType()) && 6050 "Implicit cast type cannot be determined from overload"); 6051 if (SubExpr == ICE->getSubExpr()) 6052 return ICE->Retain(); 6053 6054 return new (Context) ImplicitCastExpr(ICE->getType(), 6055 ICE->getCastKind(), 6056 SubExpr, 6057 ICE->isLvalueCast()); 6058 } 6059 6060 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 6061 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 6062 "Can only take the address of an overloaded function"); 6063 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 6064 if (Method->isStatic()) { 6065 // Do nothing: static member functions aren't any different 6066 // from non-member functions. 6067 } else { 6068 // Fix the sub expression, which really has to be an 6069 // UnresolvedLookupExpr holding an overloaded member function 6070 // or template. 6071 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), Fn); 6072 if (SubExpr == UnOp->getSubExpr()) 6073 return UnOp->Retain(); 6074 6075 assert(isa<DeclRefExpr>(SubExpr) 6076 && "fixed to something other than a decl ref"); 6077 assert(cast<DeclRefExpr>(SubExpr)->getQualifier() 6078 && "fixed to a member ref with no nested name qualifier"); 6079 6080 // We have taken the address of a pointer to member 6081 // function. Perform the computation here so that we get the 6082 // appropriate pointer to member type. 6083 QualType ClassType 6084 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 6085 QualType MemPtrType 6086 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr()); 6087 6088 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6089 MemPtrType, UnOp->getOperatorLoc()); 6090 } 6091 } 6092 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(), Fn); 6093 if (SubExpr == UnOp->getSubExpr()) 6094 return UnOp->Retain(); 6095 6096 return new (Context) UnaryOperator(SubExpr, UnaryOperator::AddrOf, 6097 Context.getPointerType(SubExpr->getType()), 6098 UnOp->getOperatorLoc()); 6099 } 6100 6101 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) { 6102 // FIXME: avoid copy. 6103 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6104 if (ULE->hasExplicitTemplateArgs()) { 6105 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer); 6106 TemplateArgs = &TemplateArgsBuffer; 6107 } 6108 6109 return DeclRefExpr::Create(Context, 6110 ULE->getQualifier(), 6111 ULE->getQualifierRange(), 6112 Fn, 6113 ULE->getNameLoc(), 6114 Fn->getType(), 6115 TemplateArgs); 6116 } 6117 6118 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) { 6119 // FIXME: avoid copy. 6120 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = 0; 6121 if (MemExpr->hasExplicitTemplateArgs()) { 6122 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer); 6123 TemplateArgs = &TemplateArgsBuffer; 6124 } 6125 6126 Expr *Base; 6127 6128 // If we're filling in 6129 if (MemExpr->isImplicitAccess()) { 6130 if (cast<CXXMethodDecl>(Fn)->isStatic()) { 6131 return DeclRefExpr::Create(Context, 6132 MemExpr->getQualifier(), 6133 MemExpr->getQualifierRange(), 6134 Fn, 6135 MemExpr->getMemberLoc(), 6136 Fn->getType(), 6137 TemplateArgs); 6138 } else { 6139 SourceLocation Loc = MemExpr->getMemberLoc(); 6140 if (MemExpr->getQualifier()) 6141 Loc = MemExpr->getQualifierRange().getBegin(); 6142 Base = new (Context) CXXThisExpr(Loc, 6143 MemExpr->getBaseType(), 6144 /*isImplicit=*/true); 6145 } 6146 } else 6147 Base = MemExpr->getBase()->Retain(); 6148 6149 return MemberExpr::Create(Context, Base, 6150 MemExpr->isArrow(), 6151 MemExpr->getQualifier(), 6152 MemExpr->getQualifierRange(), 6153 Fn, 6154 MemExpr->getMemberLoc(), 6155 TemplateArgs, 6156 Fn->getType()); 6157 } 6158 6159 assert(false && "Invalid reference to overloaded function"); 6160 return E->Retain(); 6161} 6162 6163Sema::OwningExprResult Sema::FixOverloadedFunctionReference(OwningExprResult E, 6164 FunctionDecl *Fn) { 6165 return Owned(FixOverloadedFunctionReference((Expr *)E.get(), Fn)); 6166} 6167 6168} // end namespace clang 6169