SemaOverload.cpp revision bad0e656c3732e3539a9cd6525de721d7e47408b
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 "SemaInherit.h" 16#include "clang/Basic/Diagnostic.h" 17#include "clang/Lex/Preprocessor.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/AST/Expr.h" 20#include "clang/AST/ExprCXX.h" 21#include "clang/AST/TypeOrdering.h" 22#include "llvm/ADT/SmallPtrSet.h" 23#include "llvm/ADT/STLExtras.h" 24#include "llvm/Support/Compiler.h" 25#include <algorithm> 26 27namespace clang { 28 29/// GetConversionCategory - Retrieve the implicit conversion 30/// category corresponding to the given implicit conversion kind. 31ImplicitConversionCategory 32GetConversionCategory(ImplicitConversionKind Kind) { 33 static const ImplicitConversionCategory 34 Category[(int)ICK_Num_Conversion_Kinds] = { 35 ICC_Identity, 36 ICC_Lvalue_Transformation, 37 ICC_Lvalue_Transformation, 38 ICC_Lvalue_Transformation, 39 ICC_Qualification_Adjustment, 40 ICC_Promotion, 41 ICC_Promotion, 42 ICC_Promotion, 43 ICC_Conversion, 44 ICC_Conversion, 45 ICC_Conversion, 46 ICC_Conversion, 47 ICC_Conversion, 48 ICC_Conversion, 49 ICC_Conversion, 50 ICC_Conversion, 51 ICC_Conversion, 52 ICC_Conversion 53 }; 54 return Category[(int)Kind]; 55} 56 57/// GetConversionRank - Retrieve the implicit conversion rank 58/// corresponding to the given implicit conversion kind. 59ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind) { 60 static const ImplicitConversionRank 61 Rank[(int)ICK_Num_Conversion_Kinds] = { 62 ICR_Exact_Match, 63 ICR_Exact_Match, 64 ICR_Exact_Match, 65 ICR_Exact_Match, 66 ICR_Exact_Match, 67 ICR_Promotion, 68 ICR_Promotion, 69 ICR_Promotion, 70 ICR_Conversion, 71 ICR_Conversion, 72 ICR_Conversion, 73 ICR_Conversion, 74 ICR_Conversion, 75 ICR_Conversion, 76 ICR_Conversion, 77 ICR_Conversion, 78 ICR_Conversion, 79 ICR_Conversion 80 }; 81 return Rank[(int)Kind]; 82} 83 84/// GetImplicitConversionName - Return the name of this kind of 85/// implicit conversion. 86const char* GetImplicitConversionName(ImplicitConversionKind Kind) { 87 static const char* Name[(int)ICK_Num_Conversion_Kinds] = { 88 "No conversion", 89 "Lvalue-to-rvalue", 90 "Array-to-pointer", 91 "Function-to-pointer", 92 "Qualification", 93 "Integral promotion", 94 "Floating point promotion", 95 "Complex promotion", 96 "Integral conversion", 97 "Floating conversion", 98 "Complex conversion", 99 "Floating-integral conversion", 100 "Complex-real conversion", 101 "Pointer conversion", 102 "Pointer-to-member conversion", 103 "Boolean conversion", 104 "Compatible-types conversion", 105 "Derived-to-base conversion" 106 }; 107 return Name[Kind]; 108} 109 110/// StandardConversionSequence - Set the standard conversion 111/// sequence to the identity conversion. 112void StandardConversionSequence::setAsIdentityConversion() { 113 First = ICK_Identity; 114 Second = ICK_Identity; 115 Third = ICK_Identity; 116 Deprecated = false; 117 ReferenceBinding = false; 118 DirectBinding = false; 119 CopyConstructor = 0; 120} 121 122/// getRank - Retrieve the rank of this standard conversion sequence 123/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 124/// implicit conversions. 125ImplicitConversionRank StandardConversionSequence::getRank() const { 126 ImplicitConversionRank Rank = ICR_Exact_Match; 127 if (GetConversionRank(First) > Rank) 128 Rank = GetConversionRank(First); 129 if (GetConversionRank(Second) > Rank) 130 Rank = GetConversionRank(Second); 131 if (GetConversionRank(Third) > Rank) 132 Rank = GetConversionRank(Third); 133 return Rank; 134} 135 136/// isPointerConversionToBool - Determines whether this conversion is 137/// a conversion of a pointer or pointer-to-member to bool. This is 138/// used as part of the ranking of standard conversion sequences 139/// (C++ 13.3.3.2p4). 140bool StandardConversionSequence::isPointerConversionToBool() const 141{ 142 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 143 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 144 145 // Note that FromType has not necessarily been transformed by the 146 // array-to-pointer or function-to-pointer implicit conversions, so 147 // check for their presence as well as checking whether FromType is 148 // a pointer. 149 if (ToType->isBooleanType() && 150 (FromType->isPointerType() || FromType->isBlockPointerType() || 151 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 152 return true; 153 154 return false; 155} 156 157/// isPointerConversionToVoidPointer - Determines whether this 158/// conversion is a conversion of a pointer to a void pointer. This is 159/// used as part of the ranking of standard conversion sequences (C++ 160/// 13.3.3.2p4). 161bool 162StandardConversionSequence:: 163isPointerConversionToVoidPointer(ASTContext& Context) const 164{ 165 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 166 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 167 168 // Note that FromType has not necessarily been transformed by the 169 // array-to-pointer implicit conversion, so check for its presence 170 // and redo the conversion to get a pointer. 171 if (First == ICK_Array_To_Pointer) 172 FromType = Context.getArrayDecayedType(FromType); 173 174 if (Second == ICK_Pointer_Conversion) 175 if (const PointerType* ToPtrType = ToType->getAsPointerType()) 176 return ToPtrType->getPointeeType()->isVoidType(); 177 178 return false; 179} 180 181/// DebugPrint - Print this standard conversion sequence to standard 182/// error. Useful for debugging overloading issues. 183void StandardConversionSequence::DebugPrint() const { 184 bool PrintedSomething = false; 185 if (First != ICK_Identity) { 186 fprintf(stderr, "%s", GetImplicitConversionName(First)); 187 PrintedSomething = true; 188 } 189 190 if (Second != ICK_Identity) { 191 if (PrintedSomething) { 192 fprintf(stderr, " -> "); 193 } 194 fprintf(stderr, "%s", GetImplicitConversionName(Second)); 195 196 if (CopyConstructor) { 197 fprintf(stderr, " (by copy constructor)"); 198 } else if (DirectBinding) { 199 fprintf(stderr, " (direct reference binding)"); 200 } else if (ReferenceBinding) { 201 fprintf(stderr, " (reference binding)"); 202 } 203 PrintedSomething = true; 204 } 205 206 if (Third != ICK_Identity) { 207 if (PrintedSomething) { 208 fprintf(stderr, " -> "); 209 } 210 fprintf(stderr, "%s", GetImplicitConversionName(Third)); 211 PrintedSomething = true; 212 } 213 214 if (!PrintedSomething) { 215 fprintf(stderr, "No conversions required"); 216 } 217} 218 219/// DebugPrint - Print this user-defined conversion sequence to standard 220/// error. Useful for debugging overloading issues. 221void UserDefinedConversionSequence::DebugPrint() const { 222 if (Before.First || Before.Second || Before.Third) { 223 Before.DebugPrint(); 224 fprintf(stderr, " -> "); 225 } 226 fprintf(stderr, "'%s'", ConversionFunction->getNameAsString().c_str()); 227 if (After.First || After.Second || After.Third) { 228 fprintf(stderr, " -> "); 229 After.DebugPrint(); 230 } 231} 232 233/// DebugPrint - Print this implicit conversion sequence to standard 234/// error. Useful for debugging overloading issues. 235void ImplicitConversionSequence::DebugPrint() const { 236 switch (ConversionKind) { 237 case StandardConversion: 238 fprintf(stderr, "Standard conversion: "); 239 Standard.DebugPrint(); 240 break; 241 case UserDefinedConversion: 242 fprintf(stderr, "User-defined conversion: "); 243 UserDefined.DebugPrint(); 244 break; 245 case EllipsisConversion: 246 fprintf(stderr, "Ellipsis conversion"); 247 break; 248 case BadConversion: 249 fprintf(stderr, "Bad conversion"); 250 break; 251 } 252 253 fprintf(stderr, "\n"); 254} 255 256// IsOverload - Determine whether the given New declaration is an 257// overload of the Old declaration. This routine returns false if New 258// and Old cannot be overloaded, e.g., if they are functions with the 259// same signature (C++ 1.3.10) or if the Old declaration isn't a 260// function (or overload set). When it does return false and Old is an 261// OverloadedFunctionDecl, MatchedDecl will be set to point to the 262// FunctionDecl that New cannot be overloaded with. 263// 264// Example: Given the following input: 265// 266// void f(int, float); // #1 267// void f(int, int); // #2 268// int f(int, int); // #3 269// 270// When we process #1, there is no previous declaration of "f", 271// so IsOverload will not be used. 272// 273// When we process #2, Old is a FunctionDecl for #1. By comparing the 274// parameter types, we see that #1 and #2 are overloaded (since they 275// have different signatures), so this routine returns false; 276// MatchedDecl is unchanged. 277// 278// When we process #3, Old is an OverloadedFunctionDecl containing #1 279// and #2. We compare the signatures of #3 to #1 (they're overloaded, 280// so we do nothing) and then #3 to #2. Since the signatures of #3 and 281// #2 are identical (return types of functions are not part of the 282// signature), IsOverload returns false and MatchedDecl will be set to 283// point to the FunctionDecl for #2. 284bool 285Sema::IsOverload(FunctionDecl *New, Decl* OldD, 286 OverloadedFunctionDecl::function_iterator& MatchedDecl) 287{ 288 if (OverloadedFunctionDecl* Ovl = dyn_cast<OverloadedFunctionDecl>(OldD)) { 289 // Is this new function an overload of every function in the 290 // overload set? 291 OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 292 FuncEnd = Ovl->function_end(); 293 for (; Func != FuncEnd; ++Func) { 294 if (!IsOverload(New, *Func, MatchedDecl)) { 295 MatchedDecl = Func; 296 return false; 297 } 298 } 299 300 // This function overloads every function in the overload set. 301 return true; 302 } else if (FunctionDecl* Old = dyn_cast<FunctionDecl>(OldD)) { 303 // Is the function New an overload of the function Old? 304 QualType OldQType = Context.getCanonicalType(Old->getType()); 305 QualType NewQType = Context.getCanonicalType(New->getType()); 306 307 // Compare the signatures (C++ 1.3.10) of the two functions to 308 // determine whether they are overloads. If we find any mismatch 309 // in the signature, they are overloads. 310 311 // If either of these functions is a K&R-style function (no 312 // prototype), then we consider them to have matching signatures. 313 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 314 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 315 return false; 316 317 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType.getTypePtr()); 318 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType.getTypePtr()); 319 320 // The signature of a function includes the types of its 321 // parameters (C++ 1.3.10), which includes the presence or absence 322 // of the ellipsis; see C++ DR 357). 323 if (OldQType != NewQType && 324 (OldType->getNumArgs() != NewType->getNumArgs() || 325 OldType->isVariadic() != NewType->isVariadic() || 326 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 327 NewType->arg_type_begin()))) 328 return true; 329 330 // If the function is a class member, its signature includes the 331 // cv-qualifiers (if any) on the function itself. 332 // 333 // As part of this, also check whether one of the member functions 334 // is static, in which case they are not overloads (C++ 335 // 13.1p2). While not part of the definition of the signature, 336 // this check is important to determine whether these functions 337 // can be overloaded. 338 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 339 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 340 if (OldMethod && NewMethod && 341 !OldMethod->isStatic() && !NewMethod->isStatic() && 342 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 343 return true; 344 345 // The signatures match; this is not an overload. 346 return false; 347 } else { 348 // (C++ 13p1): 349 // Only function declarations can be overloaded; object and type 350 // declarations cannot be overloaded. 351 return false; 352 } 353} 354 355/// TryImplicitConversion - Attempt to perform an implicit conversion 356/// from the given expression (Expr) to the given type (ToType). This 357/// function returns an implicit conversion sequence that can be used 358/// to perform the initialization. Given 359/// 360/// void f(float f); 361/// void g(int i) { f(i); } 362/// 363/// this routine would produce an implicit conversion sequence to 364/// describe the initialization of f from i, which will be a standard 365/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 366/// 4.1) followed by a floating-integral conversion (C++ 4.9). 367// 368/// Note that this routine only determines how the conversion can be 369/// performed; it does not actually perform the conversion. As such, 370/// it will not produce any diagnostics if no conversion is available, 371/// but will instead return an implicit conversion sequence of kind 372/// "BadConversion". 373/// 374/// If @p SuppressUserConversions, then user-defined conversions are 375/// not permitted. 376/// If @p AllowExplicit, then explicit user-defined conversions are 377/// permitted. 378ImplicitConversionSequence 379Sema::TryImplicitConversion(Expr* From, QualType ToType, 380 bool SuppressUserConversions, 381 bool AllowExplicit) 382{ 383 ImplicitConversionSequence ICS; 384 if (IsStandardConversion(From, ToType, ICS.Standard)) 385 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 386 else if (getLangOptions().CPlusPlus && 387 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 388 !SuppressUserConversions, AllowExplicit)) { 389 ICS.ConversionKind = ImplicitConversionSequence::UserDefinedConversion; 390 // C++ [over.ics.user]p4: 391 // A conversion of an expression of class type to the same class 392 // type is given Exact Match rank, and a conversion of an 393 // expression of class type to a base class of that type is 394 // given Conversion rank, in spite of the fact that a copy 395 // constructor (i.e., a user-defined conversion function) is 396 // called for those cases. 397 if (CXXConstructorDecl *Constructor 398 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 399 QualType FromCanon 400 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 401 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 402 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 403 // Turn this into a "standard" conversion sequence, so that it 404 // gets ranked with standard conversion sequences. 405 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 406 ICS.Standard.setAsIdentityConversion(); 407 ICS.Standard.FromTypePtr = From->getType().getAsOpaquePtr(); 408 ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr(); 409 ICS.Standard.CopyConstructor = Constructor; 410 if (ToCanon != FromCanon) 411 ICS.Standard.Second = ICK_Derived_To_Base; 412 } 413 } 414 415 // C++ [over.best.ics]p4: 416 // However, when considering the argument of a user-defined 417 // conversion function that is a candidate by 13.3.1.3 when 418 // invoked for the copying of the temporary in the second step 419 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 420 // 13.3.1.6 in all cases, only standard conversion sequences and 421 // ellipsis conversion sequences are allowed. 422 if (SuppressUserConversions && 423 ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion) 424 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 425 } else 426 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 427 428 return ICS; 429} 430 431/// IsStandardConversion - Determines whether there is a standard 432/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 433/// expression From to the type ToType. Standard conversion sequences 434/// only consider non-class types; for conversions that involve class 435/// types, use TryImplicitConversion. If a conversion exists, SCS will 436/// contain the standard conversion sequence required to perform this 437/// conversion and this routine will return true. Otherwise, this 438/// routine will return false and the value of SCS is unspecified. 439bool 440Sema::IsStandardConversion(Expr* From, QualType ToType, 441 StandardConversionSequence &SCS) 442{ 443 QualType FromType = From->getType(); 444 445 // Standard conversions (C++ [conv]) 446 SCS.setAsIdentityConversion(); 447 SCS.Deprecated = false; 448 SCS.IncompatibleObjC = false; 449 SCS.FromTypePtr = FromType.getAsOpaquePtr(); 450 SCS.CopyConstructor = 0; 451 452 // There are no standard conversions for class types in C++, so 453 // abort early. When overloading in C, however, we do permit 454 if (FromType->isRecordType() || ToType->isRecordType()) { 455 if (getLangOptions().CPlusPlus) 456 return false; 457 458 // When we're overloading in C, we allow, as standard conversions, 459 } 460 461 // The first conversion can be an lvalue-to-rvalue conversion, 462 // array-to-pointer conversion, or function-to-pointer conversion 463 // (C++ 4p1). 464 465 // Lvalue-to-rvalue conversion (C++ 4.1): 466 // An lvalue (3.10) of a non-function, non-array type T can be 467 // converted to an rvalue. 468 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 469 if (argIsLvalue == Expr::LV_Valid && 470 !FromType->isFunctionType() && !FromType->isArrayType() && 471 Context.getCanonicalType(FromType) != Context.OverloadTy) { 472 SCS.First = ICK_Lvalue_To_Rvalue; 473 474 // If T is a non-class type, the type of the rvalue is the 475 // cv-unqualified version of T. Otherwise, the type of the rvalue 476 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 477 // just strip the qualifiers because they don't matter. 478 479 // FIXME: Doesn't see through to qualifiers behind a typedef! 480 FromType = FromType.getUnqualifiedType(); 481 } 482 // Array-to-pointer conversion (C++ 4.2) 483 else if (FromType->isArrayType()) { 484 SCS.First = ICK_Array_To_Pointer; 485 486 // An lvalue or rvalue of type "array of N T" or "array of unknown 487 // bound of T" can be converted to an rvalue of type "pointer to 488 // T" (C++ 4.2p1). 489 FromType = Context.getArrayDecayedType(FromType); 490 491 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 492 // This conversion is deprecated. (C++ D.4). 493 SCS.Deprecated = true; 494 495 // For the purpose of ranking in overload resolution 496 // (13.3.3.1.1), this conversion is considered an 497 // array-to-pointer conversion followed by a qualification 498 // conversion (4.4). (C++ 4.2p2) 499 SCS.Second = ICK_Identity; 500 SCS.Third = ICK_Qualification; 501 SCS.ToTypePtr = ToType.getAsOpaquePtr(); 502 return true; 503 } 504 } 505 // Function-to-pointer conversion (C++ 4.3). 506 else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 507 SCS.First = ICK_Function_To_Pointer; 508 509 // An lvalue of function type T can be converted to an rvalue of 510 // type "pointer to T." The result is a pointer to the 511 // function. (C++ 4.3p1). 512 FromType = Context.getPointerType(FromType); 513 } 514 // Address of overloaded function (C++ [over.over]). 515 else if (FunctionDecl *Fn 516 = ResolveAddressOfOverloadedFunction(From, ToType, false)) { 517 SCS.First = ICK_Function_To_Pointer; 518 519 // We were able to resolve the address of the overloaded function, 520 // so we can convert to the type of that function. 521 FromType = Fn->getType(); 522 if (ToType->isLValueReferenceType()) 523 FromType = Context.getLValueReferenceType(FromType); 524 else if (ToType->isRValueReferenceType()) 525 FromType = Context.getRValueReferenceType(FromType); 526 else if (ToType->isMemberPointerType()) { 527 // Resolve address only succeeds if both sides are member pointers, 528 // but it doesn't have to be the same class. See DR 247. 529 // Note that this means that the type of &Derived::fn can be 530 // Ret (Base::*)(Args) if the fn overload actually found is from the 531 // base class, even if it was brought into the derived class via a 532 // using declaration. The standard isn't clear on this issue at all. 533 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 534 FromType = Context.getMemberPointerType(FromType, 535 Context.getTypeDeclType(M->getParent()).getTypePtr()); 536 } else 537 FromType = Context.getPointerType(FromType); 538 } 539 // We don't require any conversions for the first step. 540 else { 541 SCS.First = ICK_Identity; 542 } 543 544 // The second conversion can be an integral promotion, floating 545 // point promotion, integral conversion, floating point conversion, 546 // floating-integral conversion, pointer conversion, 547 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 548 // For overloading in C, this can also be a "compatible-type" 549 // conversion. 550 bool IncompatibleObjC = false; 551 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 552 // The unqualified versions of the types are the same: there's no 553 // conversion to do. 554 SCS.Second = ICK_Identity; 555 } 556 // Integral promotion (C++ 4.5). 557 else if (IsIntegralPromotion(From, FromType, ToType)) { 558 SCS.Second = ICK_Integral_Promotion; 559 FromType = ToType.getUnqualifiedType(); 560 } 561 // Floating point promotion (C++ 4.6). 562 else if (IsFloatingPointPromotion(FromType, ToType)) { 563 SCS.Second = ICK_Floating_Promotion; 564 FromType = ToType.getUnqualifiedType(); 565 } 566 // Complex promotion (Clang extension) 567 else if (IsComplexPromotion(FromType, ToType)) { 568 SCS.Second = ICK_Complex_Promotion; 569 FromType = ToType.getUnqualifiedType(); 570 } 571 // Integral conversions (C++ 4.7). 572 // FIXME: isIntegralType shouldn't be true for enums in C++. 573 else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 574 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 575 SCS.Second = ICK_Integral_Conversion; 576 FromType = ToType.getUnqualifiedType(); 577 } 578 // Floating point conversions (C++ 4.8). 579 else if (FromType->isFloatingType() && ToType->isFloatingType()) { 580 SCS.Second = ICK_Floating_Conversion; 581 FromType = ToType.getUnqualifiedType(); 582 } 583 // Complex conversions (C99 6.3.1.6) 584 else if (FromType->isComplexType() && ToType->isComplexType()) { 585 SCS.Second = ICK_Complex_Conversion; 586 FromType = ToType.getUnqualifiedType(); 587 } 588 // Floating-integral conversions (C++ 4.9). 589 // FIXME: isIntegralType shouldn't be true for enums in C++. 590 else if ((FromType->isFloatingType() && 591 ToType->isIntegralType() && !ToType->isBooleanType() && 592 !ToType->isEnumeralType()) || 593 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 594 ToType->isFloatingType())) { 595 SCS.Second = ICK_Floating_Integral; 596 FromType = ToType.getUnqualifiedType(); 597 } 598 // Complex-real conversions (C99 6.3.1.7) 599 else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 600 (ToType->isComplexType() && FromType->isArithmeticType())) { 601 SCS.Second = ICK_Complex_Real; 602 FromType = ToType.getUnqualifiedType(); 603 } 604 // Pointer conversions (C++ 4.10). 605 else if (IsPointerConversion(From, FromType, ToType, FromType, 606 IncompatibleObjC)) { 607 SCS.Second = ICK_Pointer_Conversion; 608 SCS.IncompatibleObjC = IncompatibleObjC; 609 } 610 // Pointer to member conversions (4.11). 611 else if (IsMemberPointerConversion(From, FromType, ToType, FromType)) { 612 SCS.Second = ICK_Pointer_Member; 613 } 614 // Boolean conversions (C++ 4.12). 615 else if (ToType->isBooleanType() && 616 (FromType->isArithmeticType() || 617 FromType->isEnumeralType() || 618 FromType->isPointerType() || 619 FromType->isBlockPointerType() || 620 FromType->isMemberPointerType())) { 621 SCS.Second = ICK_Boolean_Conversion; 622 FromType = Context.BoolTy; 623 } 624 // Compatible conversions (Clang extension for C function overloading) 625 else if (!getLangOptions().CPlusPlus && 626 Context.typesAreCompatible(ToType, FromType)) { 627 SCS.Second = ICK_Compatible_Conversion; 628 } else { 629 // No second conversion required. 630 SCS.Second = ICK_Identity; 631 } 632 633 QualType CanonFrom; 634 QualType CanonTo; 635 // The third conversion can be a qualification conversion (C++ 4p1). 636 if (IsQualificationConversion(FromType, ToType)) { 637 SCS.Third = ICK_Qualification; 638 FromType = ToType; 639 CanonFrom = Context.getCanonicalType(FromType); 640 CanonTo = Context.getCanonicalType(ToType); 641 } else { 642 // No conversion required 643 SCS.Third = ICK_Identity; 644 645 // C++ [over.best.ics]p6: 646 // [...] Any difference in top-level cv-qualification is 647 // subsumed by the initialization itself and does not constitute 648 // a conversion. [...] 649 CanonFrom = Context.getCanonicalType(FromType); 650 CanonTo = Context.getCanonicalType(ToType); 651 if (CanonFrom.getUnqualifiedType() == CanonTo.getUnqualifiedType() && 652 CanonFrom.getCVRQualifiers() != CanonTo.getCVRQualifiers()) { 653 FromType = ToType; 654 CanonFrom = CanonTo; 655 } 656 } 657 658 // If we have not converted the argument type to the parameter type, 659 // this is a bad conversion sequence. 660 if (CanonFrom != CanonTo) 661 return false; 662 663 SCS.ToTypePtr = FromType.getAsOpaquePtr(); 664 return true; 665} 666 667/// IsIntegralPromotion - Determines whether the conversion from the 668/// expression From (whose potentially-adjusted type is FromType) to 669/// ToType is an integral promotion (C++ 4.5). If so, returns true and 670/// sets PromotedType to the promoted type. 671bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) 672{ 673 const BuiltinType *To = ToType->getAsBuiltinType(); 674 // All integers are built-in. 675 if (!To) { 676 return false; 677 } 678 679 // An rvalue of type char, signed char, unsigned char, short int, or 680 // unsigned short int can be converted to an rvalue of type int if 681 // int can represent all the values of the source type; otherwise, 682 // the source rvalue can be converted to an rvalue of type unsigned 683 // int (C++ 4.5p1). 684 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType()) { 685 if (// We can promote any signed, promotable integer type to an int 686 (FromType->isSignedIntegerType() || 687 // We can promote any unsigned integer type whose size is 688 // less than int to an int. 689 (!FromType->isSignedIntegerType() && 690 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 691 return To->getKind() == BuiltinType::Int; 692 } 693 694 return To->getKind() == BuiltinType::UInt; 695 } 696 697 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 698 // can be converted to an rvalue of the first of the following types 699 // that can represent all the values of its underlying type: int, 700 // unsigned int, long, or unsigned long (C++ 4.5p2). 701 if ((FromType->isEnumeralType() || FromType->isWideCharType()) 702 && ToType->isIntegerType()) { 703 // Determine whether the type we're converting from is signed or 704 // unsigned. 705 bool FromIsSigned; 706 uint64_t FromSize = Context.getTypeSize(FromType); 707 if (const EnumType *FromEnumType = FromType->getAsEnumType()) { 708 QualType UnderlyingType = FromEnumType->getDecl()->getIntegerType(); 709 FromIsSigned = UnderlyingType->isSignedIntegerType(); 710 } else { 711 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 712 FromIsSigned = true; 713 } 714 715 // The types we'll try to promote to, in the appropriate 716 // order. Try each of these types. 717 QualType PromoteTypes[6] = { 718 Context.IntTy, Context.UnsignedIntTy, 719 Context.LongTy, Context.UnsignedLongTy , 720 Context.LongLongTy, Context.UnsignedLongLongTy 721 }; 722 for (int Idx = 0; Idx < 6; ++Idx) { 723 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 724 if (FromSize < ToSize || 725 (FromSize == ToSize && 726 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 727 // We found the type that we can promote to. If this is the 728 // type we wanted, we have a promotion. Otherwise, no 729 // promotion. 730 return Context.getCanonicalType(ToType).getUnqualifiedType() 731 == Context.getCanonicalType(PromoteTypes[Idx]).getUnqualifiedType(); 732 } 733 } 734 } 735 736 // An rvalue for an integral bit-field (9.6) can be converted to an 737 // rvalue of type int if int can represent all the values of the 738 // bit-field; otherwise, it can be converted to unsigned int if 739 // unsigned int can represent all the values of the bit-field. If 740 // the bit-field is larger yet, no integral promotion applies to 741 // it. If the bit-field has an enumerated type, it is treated as any 742 // other value of that type for promotion purposes (C++ 4.5p3). 743 // FIXME: We should delay checking of bit-fields until we actually 744 // perform the conversion. 745 if (MemberExpr *MemRef = dyn_cast_or_null<MemberExpr>(From)) { 746 using llvm::APSInt; 747 if (FieldDecl *MemberDecl = dyn_cast<FieldDecl>(MemRef->getMemberDecl())) { 748 APSInt BitWidth; 749 if (MemberDecl->isBitField() && 750 FromType->isIntegralType() && !FromType->isEnumeralType() && 751 From->isIntegerConstantExpr(BitWidth, Context)) { 752 APSInt ToSize(Context.getTypeSize(ToType)); 753 754 // Are we promoting to an int from a bitfield that fits in an int? 755 if (BitWidth < ToSize || 756 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 757 return To->getKind() == BuiltinType::Int; 758 } 759 760 // Are we promoting to an unsigned int from an unsigned bitfield 761 // that fits into an unsigned int? 762 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 763 return To->getKind() == BuiltinType::UInt; 764 } 765 766 return false; 767 } 768 } 769 } 770 771 // An rvalue of type bool can be converted to an rvalue of type int, 772 // with false becoming zero and true becoming one (C++ 4.5p4). 773 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 774 return true; 775 } 776 777 return false; 778} 779 780/// IsFloatingPointPromotion - Determines whether the conversion from 781/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 782/// returns true and sets PromotedType to the promoted type. 783bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) 784{ 785 /// An rvalue of type float can be converted to an rvalue of type 786 /// double. (C++ 4.6p1). 787 if (const BuiltinType *FromBuiltin = FromType->getAsBuiltinType()) 788 if (const BuiltinType *ToBuiltin = ToType->getAsBuiltinType()) { 789 if (FromBuiltin->getKind() == BuiltinType::Float && 790 ToBuiltin->getKind() == BuiltinType::Double) 791 return true; 792 793 // C99 6.3.1.5p1: 794 // When a float is promoted to double or long double, or a 795 // double is promoted to long double [...]. 796 if (!getLangOptions().CPlusPlus && 797 (FromBuiltin->getKind() == BuiltinType::Float || 798 FromBuiltin->getKind() == BuiltinType::Double) && 799 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 800 return true; 801 } 802 803 return false; 804} 805 806/// \brief Determine if a conversion is a complex promotion. 807/// 808/// A complex promotion is defined as a complex -> complex conversion 809/// where the conversion between the underlying real types is a 810/// floating-point or integral promotion. 811bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 812 const ComplexType *FromComplex = FromType->getAsComplexType(); 813 if (!FromComplex) 814 return false; 815 816 const ComplexType *ToComplex = ToType->getAsComplexType(); 817 if (!ToComplex) 818 return false; 819 820 return IsFloatingPointPromotion(FromComplex->getElementType(), 821 ToComplex->getElementType()) || 822 IsIntegralPromotion(0, FromComplex->getElementType(), 823 ToComplex->getElementType()); 824} 825 826/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 827/// the pointer type FromPtr to a pointer to type ToPointee, with the 828/// same type qualifiers as FromPtr has on its pointee type. ToType, 829/// if non-empty, will be a pointer to ToType that may or may not have 830/// the right set of qualifiers on its pointee. 831static QualType 832BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 833 QualType ToPointee, QualType ToType, 834 ASTContext &Context) { 835 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 836 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 837 unsigned Quals = CanonFromPointee.getCVRQualifiers(); 838 839 // Exact qualifier match -> return the pointer type we're converting to. 840 if (CanonToPointee.getCVRQualifiers() == Quals) { 841 // ToType is exactly what we need. Return it. 842 if (ToType.getTypePtr()) 843 return ToType; 844 845 // Build a pointer to ToPointee. It has the right qualifiers 846 // already. 847 return Context.getPointerType(ToPointee); 848 } 849 850 // Just build a canonical type that has the right qualifiers. 851 return Context.getPointerType(CanonToPointee.getQualifiedType(Quals)); 852} 853 854/// IsPointerConversion - Determines whether the conversion of the 855/// expression From, which has the (possibly adjusted) type FromType, 856/// can be converted to the type ToType via a pointer conversion (C++ 857/// 4.10). If so, returns true and places the converted type (that 858/// might differ from ToType in its cv-qualifiers at some level) into 859/// ConvertedType. 860/// 861/// This routine also supports conversions to and from block pointers 862/// and conversions with Objective-C's 'id', 'id<protocols...>', and 863/// pointers to interfaces. FIXME: Once we've determined the 864/// appropriate overloading rules for Objective-C, we may want to 865/// split the Objective-C checks into a different routine; however, 866/// GCC seems to consider all of these conversions to be pointer 867/// conversions, so for now they live here. IncompatibleObjC will be 868/// set if the conversion is an allowed Objective-C conversion that 869/// should result in a warning. 870bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 871 QualType& ConvertedType, 872 bool &IncompatibleObjC) 873{ 874 IncompatibleObjC = false; 875 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 876 return true; 877 878 // Conversion from a null pointer constant to any Objective-C pointer type. 879 if (Context.isObjCObjectPointerType(ToType) && 880 From->isNullPointerConstant(Context)) { 881 ConvertedType = ToType; 882 return true; 883 } 884 885 // Blocks: Block pointers can be converted to void*. 886 if (FromType->isBlockPointerType() && ToType->isPointerType() && 887 ToType->getAsPointerType()->getPointeeType()->isVoidType()) { 888 ConvertedType = ToType; 889 return true; 890 } 891 // Blocks: A null pointer constant can be converted to a block 892 // pointer type. 893 if (ToType->isBlockPointerType() && From->isNullPointerConstant(Context)) { 894 ConvertedType = ToType; 895 return true; 896 } 897 898 const PointerType* ToTypePtr = ToType->getAsPointerType(); 899 if (!ToTypePtr) 900 return false; 901 902 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 903 if (From->isNullPointerConstant(Context)) { 904 ConvertedType = ToType; 905 return true; 906 } 907 908 // Beyond this point, both types need to be pointers. 909 const PointerType *FromTypePtr = FromType->getAsPointerType(); 910 if (!FromTypePtr) 911 return false; 912 913 QualType FromPointeeType = FromTypePtr->getPointeeType(); 914 QualType ToPointeeType = ToTypePtr->getPointeeType(); 915 916 // An rvalue of type "pointer to cv T," where T is an object type, 917 // can be converted to an rvalue of type "pointer to cv void" (C++ 918 // 4.10p2). 919 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 920 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 921 ToPointeeType, 922 ToType, Context); 923 return true; 924 } 925 926 // When we're overloading in C, we allow a special kind of pointer 927 // conversion for compatible-but-not-identical pointee types. 928 if (!getLangOptions().CPlusPlus && 929 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 930 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 931 ToPointeeType, 932 ToType, Context); 933 return true; 934 } 935 936 // C++ [conv.ptr]p3: 937 // 938 // An rvalue of type "pointer to cv D," where D is a class type, 939 // can be converted to an rvalue of type "pointer to cv B," where 940 // B is a base class (clause 10) of D. If B is an inaccessible 941 // (clause 11) or ambiguous (10.2) base class of D, a program that 942 // necessitates this conversion is ill-formed. The result of the 943 // conversion is a pointer to the base class sub-object of the 944 // derived class object. The null pointer value is converted to 945 // the null pointer value of the destination type. 946 // 947 // Note that we do not check for ambiguity or inaccessibility 948 // here. That is handled by CheckPointerConversion. 949 if (getLangOptions().CPlusPlus && 950 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 951 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 952 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 953 ToPointeeType, 954 ToType, Context); 955 return true; 956 } 957 958 return false; 959} 960 961/// isObjCPointerConversion - Determines whether this is an 962/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 963/// with the same arguments and return values. 964bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 965 QualType& ConvertedType, 966 bool &IncompatibleObjC) { 967 if (!getLangOptions().ObjC1) 968 return false; 969 970 // Conversions with Objective-C's id<...>. 971 if ((FromType->isObjCQualifiedIdType() || ToType->isObjCQualifiedIdType()) && 972 ObjCQualifiedIdTypesAreCompatible(ToType, FromType, /*compare=*/false)) { 973 ConvertedType = ToType; 974 return true; 975 } 976 977 // Beyond this point, both types need to be pointers or block pointers. 978 QualType ToPointeeType; 979 const PointerType* ToTypePtr = ToType->getAsPointerType(); 980 if (ToTypePtr) 981 ToPointeeType = ToTypePtr->getPointeeType(); 982 else if (const BlockPointerType *ToBlockPtr = ToType->getAsBlockPointerType()) 983 ToPointeeType = ToBlockPtr->getPointeeType(); 984 else 985 return false; 986 987 QualType FromPointeeType; 988 const PointerType *FromTypePtr = FromType->getAsPointerType(); 989 if (FromTypePtr) 990 FromPointeeType = FromTypePtr->getPointeeType(); 991 else if (const BlockPointerType *FromBlockPtr 992 = FromType->getAsBlockPointerType()) 993 FromPointeeType = FromBlockPtr->getPointeeType(); 994 else 995 return false; 996 997 // Objective C++: We're able to convert from a pointer to an 998 // interface to a pointer to a different interface. 999 const ObjCInterfaceType* FromIface = FromPointeeType->getAsObjCInterfaceType(); 1000 const ObjCInterfaceType* ToIface = ToPointeeType->getAsObjCInterfaceType(); 1001 if (FromIface && ToIface && 1002 Context.canAssignObjCInterfaces(ToIface, FromIface)) { 1003 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1004 ToPointeeType, 1005 ToType, Context); 1006 return true; 1007 } 1008 1009 if (FromIface && ToIface && 1010 Context.canAssignObjCInterfaces(FromIface, ToIface)) { 1011 // Okay: this is some kind of implicit downcast of Objective-C 1012 // interfaces, which is permitted. However, we're going to 1013 // complain about it. 1014 IncompatibleObjC = true; 1015 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1016 ToPointeeType, 1017 ToType, Context); 1018 return true; 1019 } 1020 1021 // Objective C++: We're able to convert between "id" and a pointer 1022 // to any interface (in both directions). 1023 if ((FromIface && Context.isObjCIdStructType(ToPointeeType)) 1024 || (ToIface && Context.isObjCIdStructType(FromPointeeType))) { 1025 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1026 ToPointeeType, 1027 ToType, Context); 1028 return true; 1029 } 1030 1031 // Objective C++: Allow conversions between the Objective-C "id" and 1032 // "Class", in either direction. 1033 if ((Context.isObjCIdStructType(FromPointeeType) && 1034 Context.isObjCClassStructType(ToPointeeType)) || 1035 (Context.isObjCClassStructType(FromPointeeType) && 1036 Context.isObjCIdStructType(ToPointeeType))) { 1037 ConvertedType = ToType; 1038 return true; 1039 } 1040 1041 // If we have pointers to pointers, recursively check whether this 1042 // is an Objective-C conversion. 1043 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1044 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1045 IncompatibleObjC)) { 1046 // We always complain about this conversion. 1047 IncompatibleObjC = true; 1048 ConvertedType = ToType; 1049 return true; 1050 } 1051 1052 // If we have pointers to functions or blocks, check whether the only 1053 // differences in the argument and result types are in Objective-C 1054 // pointer conversions. If so, we permit the conversion (but 1055 // complain about it). 1056 const FunctionProtoType *FromFunctionType 1057 = FromPointeeType->getAsFunctionProtoType(); 1058 const FunctionProtoType *ToFunctionType 1059 = ToPointeeType->getAsFunctionProtoType(); 1060 if (FromFunctionType && ToFunctionType) { 1061 // If the function types are exactly the same, this isn't an 1062 // Objective-C pointer conversion. 1063 if (Context.getCanonicalType(FromPointeeType) 1064 == Context.getCanonicalType(ToPointeeType)) 1065 return false; 1066 1067 // Perform the quick checks that will tell us whether these 1068 // function types are obviously different. 1069 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1070 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1071 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1072 return false; 1073 1074 bool HasObjCConversion = false; 1075 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1076 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1077 // Okay, the types match exactly. Nothing to do. 1078 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1079 ToFunctionType->getResultType(), 1080 ConvertedType, IncompatibleObjC)) { 1081 // Okay, we have an Objective-C pointer conversion. 1082 HasObjCConversion = true; 1083 } else { 1084 // Function types are too different. Abort. 1085 return false; 1086 } 1087 1088 // Check argument types. 1089 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1090 ArgIdx != NumArgs; ++ArgIdx) { 1091 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1092 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1093 if (Context.getCanonicalType(FromArgType) 1094 == Context.getCanonicalType(ToArgType)) { 1095 // Okay, the types match exactly. Nothing to do. 1096 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1097 ConvertedType, IncompatibleObjC)) { 1098 // Okay, we have an Objective-C pointer conversion. 1099 HasObjCConversion = true; 1100 } else { 1101 // Argument types are too different. Abort. 1102 return false; 1103 } 1104 } 1105 1106 if (HasObjCConversion) { 1107 // We had an Objective-C conversion. Allow this pointer 1108 // conversion, but complain about it. 1109 ConvertedType = ToType; 1110 IncompatibleObjC = true; 1111 return true; 1112 } 1113 } 1114 1115 return false; 1116} 1117 1118/// CheckPointerConversion - Check the pointer conversion from the 1119/// expression From to the type ToType. This routine checks for 1120/// ambiguous (FIXME: or inaccessible) derived-to-base pointer 1121/// conversions for which IsPointerConversion has already returned 1122/// true. It returns true and produces a diagnostic if there was an 1123/// error, or returns false otherwise. 1124bool Sema::CheckPointerConversion(Expr *From, QualType ToType) { 1125 QualType FromType = From->getType(); 1126 1127 if (const PointerType *FromPtrType = FromType->getAsPointerType()) 1128 if (const PointerType *ToPtrType = ToType->getAsPointerType()) { 1129 QualType FromPointeeType = FromPtrType->getPointeeType(), 1130 ToPointeeType = ToPtrType->getPointeeType(); 1131 1132 // Objective-C++ conversions are always okay. 1133 // FIXME: We should have a different class of conversions for 1134 // the Objective-C++ implicit conversions. 1135 if (Context.isObjCIdStructType(FromPointeeType) || 1136 Context.isObjCIdStructType(ToPointeeType) || 1137 Context.isObjCClassStructType(FromPointeeType) || 1138 Context.isObjCClassStructType(ToPointeeType)) 1139 return false; 1140 1141 if (FromPointeeType->isRecordType() && 1142 ToPointeeType->isRecordType()) { 1143 // We must have a derived-to-base conversion. Check an 1144 // ambiguous or inaccessible conversion. 1145 return CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1146 From->getExprLoc(), 1147 From->getSourceRange()); 1148 } 1149 } 1150 1151 return false; 1152} 1153 1154/// IsMemberPointerConversion - Determines whether the conversion of the 1155/// expression From, which has the (possibly adjusted) type FromType, can be 1156/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1157/// If so, returns true and places the converted type (that might differ from 1158/// ToType in its cv-qualifiers at some level) into ConvertedType. 1159bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1160 QualType ToType, QualType &ConvertedType) 1161{ 1162 const MemberPointerType *ToTypePtr = ToType->getAsMemberPointerType(); 1163 if (!ToTypePtr) 1164 return false; 1165 1166 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1167 if (From->isNullPointerConstant(Context)) { 1168 ConvertedType = ToType; 1169 return true; 1170 } 1171 1172 // Otherwise, both types have to be member pointers. 1173 const MemberPointerType *FromTypePtr = FromType->getAsMemberPointerType(); 1174 if (!FromTypePtr) 1175 return false; 1176 1177 // A pointer to member of B can be converted to a pointer to member of D, 1178 // where D is derived from B (C++ 4.11p2). 1179 QualType FromClass(FromTypePtr->getClass(), 0); 1180 QualType ToClass(ToTypePtr->getClass(), 0); 1181 // FIXME: What happens when these are dependent? Is this function even called? 1182 1183 if (IsDerivedFrom(ToClass, FromClass)) { 1184 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1185 ToClass.getTypePtr()); 1186 return true; 1187 } 1188 1189 return false; 1190} 1191 1192/// CheckMemberPointerConversion - Check the member pointer conversion from the 1193/// expression From to the type ToType. This routine checks for ambiguous or 1194/// virtual (FIXME: or inaccessible) base-to-derived member pointer conversions 1195/// for which IsMemberPointerConversion has already returned true. It returns 1196/// true and produces a diagnostic if there was an error, or returns false 1197/// otherwise. 1198bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType) { 1199 QualType FromType = From->getType(); 1200 const MemberPointerType *FromPtrType = FromType->getAsMemberPointerType(); 1201 if (!FromPtrType) 1202 return false; 1203 1204 const MemberPointerType *ToPtrType = ToType->getAsMemberPointerType(); 1205 assert(ToPtrType && "No member pointer cast has a target type " 1206 "that is not a member pointer."); 1207 1208 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1209 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1210 1211 // FIXME: What about dependent types? 1212 assert(FromClass->isRecordType() && "Pointer into non-class."); 1213 assert(ToClass->isRecordType() && "Pointer into non-class."); 1214 1215 BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, 1216 /*DetectVirtual=*/true); 1217 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1218 assert(DerivationOkay && 1219 "Should not have been called if derivation isn't OK."); 1220 (void)DerivationOkay; 1221 1222 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1223 getUnqualifiedType())) { 1224 // Derivation is ambiguous. Redo the check to find the exact paths. 1225 Paths.clear(); 1226 Paths.setRecordingPaths(true); 1227 bool StillOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1228 assert(StillOkay && "Derivation changed due to quantum fluctuation."); 1229 (void)StillOkay; 1230 1231 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1232 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1233 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1234 return true; 1235 } 1236 1237 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1238 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1239 << FromClass << ToClass << QualType(VBase, 0) 1240 << From->getSourceRange(); 1241 return true; 1242 } 1243 1244 return false; 1245} 1246 1247/// IsQualificationConversion - Determines whether the conversion from 1248/// an rvalue of type FromType to ToType is a qualification conversion 1249/// (C++ 4.4). 1250bool 1251Sema::IsQualificationConversion(QualType FromType, QualType ToType) 1252{ 1253 FromType = Context.getCanonicalType(FromType); 1254 ToType = Context.getCanonicalType(ToType); 1255 1256 // If FromType and ToType are the same type, this is not a 1257 // qualification conversion. 1258 if (FromType == ToType) 1259 return false; 1260 1261 // (C++ 4.4p4): 1262 // A conversion can add cv-qualifiers at levels other than the first 1263 // in multi-level pointers, subject to the following rules: [...] 1264 bool PreviousToQualsIncludeConst = true; 1265 bool UnwrappedAnyPointer = false; 1266 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1267 // Within each iteration of the loop, we check the qualifiers to 1268 // determine if this still looks like a qualification 1269 // conversion. Then, if all is well, we unwrap one more level of 1270 // pointers or pointers-to-members and do it all again 1271 // until there are no more pointers or pointers-to-members left to 1272 // unwrap. 1273 UnwrappedAnyPointer = true; 1274 1275 // -- for every j > 0, if const is in cv 1,j then const is in cv 1276 // 2,j, and similarly for volatile. 1277 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1278 return false; 1279 1280 // -- if the cv 1,j and cv 2,j are different, then const is in 1281 // every cv for 0 < k < j. 1282 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1283 && !PreviousToQualsIncludeConst) 1284 return false; 1285 1286 // Keep track of whether all prior cv-qualifiers in the "to" type 1287 // include const. 1288 PreviousToQualsIncludeConst 1289 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1290 } 1291 1292 // We are left with FromType and ToType being the pointee types 1293 // after unwrapping the original FromType and ToType the same number 1294 // of types. If we unwrapped any pointers, and if FromType and 1295 // ToType have the same unqualified type (since we checked 1296 // qualifiers above), then this is a qualification conversion. 1297 return UnwrappedAnyPointer && 1298 FromType.getUnqualifiedType() == ToType.getUnqualifiedType(); 1299} 1300 1301/// Determines whether there is a user-defined conversion sequence 1302/// (C++ [over.ics.user]) that converts expression From to the type 1303/// ToType. If such a conversion exists, User will contain the 1304/// user-defined conversion sequence that performs such a conversion 1305/// and this routine will return true. Otherwise, this routine returns 1306/// false and User is unspecified. 1307/// 1308/// \param AllowConversionFunctions true if the conversion should 1309/// consider conversion functions at all. If false, only constructors 1310/// will be considered. 1311/// 1312/// \param AllowExplicit true if the conversion should consider C++0x 1313/// "explicit" conversion functions as well as non-explicit conversion 1314/// functions (C++0x [class.conv.fct]p2). 1315bool Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1316 UserDefinedConversionSequence& User, 1317 bool AllowConversionFunctions, 1318 bool AllowExplicit) 1319{ 1320 OverloadCandidateSet CandidateSet; 1321 if (const RecordType *ToRecordType = ToType->getAsRecordType()) { 1322 if (CXXRecordDecl *ToRecordDecl 1323 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1324 // C++ [over.match.ctor]p1: 1325 // When objects of class type are direct-initialized (8.5), or 1326 // copy-initialized from an expression of the same or a 1327 // derived class type (8.5), overload resolution selects the 1328 // constructor. [...] For copy-initialization, the candidate 1329 // functions are all the converting constructors (12.3.1) of 1330 // that class. The argument list is the expression-list within 1331 // the parentheses of the initializer. 1332 DeclarationName ConstructorName 1333 = Context.DeclarationNames.getCXXConstructorName( 1334 Context.getCanonicalType(ToType).getUnqualifiedType()); 1335 DeclContext::lookup_iterator Con, ConEnd; 1336 for (llvm::tie(Con, ConEnd) = ToRecordDecl->lookup(ConstructorName); 1337 Con != ConEnd; ++Con) { 1338 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con); 1339 if (Constructor->isConvertingConstructor()) 1340 AddOverloadCandidate(Constructor, &From, 1, CandidateSet, 1341 /*SuppressUserConversions=*/true); 1342 } 1343 } 1344 } 1345 1346 if (!AllowConversionFunctions) { 1347 // Don't allow any conversion functions to enter the overload set. 1348 } else if (const RecordType *FromRecordType 1349 = From->getType()->getAsRecordType()) { 1350 if (CXXRecordDecl *FromRecordDecl 1351 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1352 // Add all of the conversion functions as candidates. 1353 // FIXME: Look for conversions in base classes! 1354 OverloadedFunctionDecl *Conversions 1355 = FromRecordDecl->getConversionFunctions(); 1356 for (OverloadedFunctionDecl::function_iterator Func 1357 = Conversions->function_begin(); 1358 Func != Conversions->function_end(); ++Func) { 1359 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 1360 if (AllowExplicit || !Conv->isExplicit()) 1361 AddConversionCandidate(Conv, From, ToType, CandidateSet); 1362 } 1363 } 1364 } 1365 1366 OverloadCandidateSet::iterator Best; 1367 switch (BestViableFunction(CandidateSet, Best)) { 1368 case OR_Success: 1369 // Record the standard conversion we used and the conversion function. 1370 if (CXXConstructorDecl *Constructor 1371 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1372 // C++ [over.ics.user]p1: 1373 // If the user-defined conversion is specified by a 1374 // constructor (12.3.1), the initial standard conversion 1375 // sequence converts the source type to the type required by 1376 // the argument of the constructor. 1377 // 1378 // FIXME: What about ellipsis conversions? 1379 QualType ThisType = Constructor->getThisType(Context); 1380 User.Before = Best->Conversions[0].Standard; 1381 User.ConversionFunction = Constructor; 1382 User.After.setAsIdentityConversion(); 1383 User.After.FromTypePtr 1384 = ThisType->getAsPointerType()->getPointeeType().getAsOpaquePtr(); 1385 User.After.ToTypePtr = ToType.getAsOpaquePtr(); 1386 return true; 1387 } else if (CXXConversionDecl *Conversion 1388 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1389 // C++ [over.ics.user]p1: 1390 // 1391 // [...] If the user-defined conversion is specified by a 1392 // conversion function (12.3.2), the initial standard 1393 // conversion sequence converts the source type to the 1394 // implicit object parameter of the conversion function. 1395 User.Before = Best->Conversions[0].Standard; 1396 User.ConversionFunction = Conversion; 1397 1398 // C++ [over.ics.user]p2: 1399 // The second standard conversion sequence converts the 1400 // result of the user-defined conversion to the target type 1401 // for the sequence. Since an implicit conversion sequence 1402 // is an initialization, the special rules for 1403 // initialization by user-defined conversion apply when 1404 // selecting the best user-defined conversion for a 1405 // user-defined conversion sequence (see 13.3.3 and 1406 // 13.3.3.1). 1407 User.After = Best->FinalConversion; 1408 return true; 1409 } else { 1410 assert(false && "Not a constructor or conversion function?"); 1411 return false; 1412 } 1413 1414 case OR_No_Viable_Function: 1415 case OR_Deleted: 1416 // No conversion here! We're done. 1417 return false; 1418 1419 case OR_Ambiguous: 1420 // FIXME: See C++ [over.best.ics]p10 for the handling of 1421 // ambiguous conversion sequences. 1422 return false; 1423 } 1424 1425 return false; 1426} 1427 1428/// CompareImplicitConversionSequences - Compare two implicit 1429/// conversion sequences to determine whether one is better than the 1430/// other or if they are indistinguishable (C++ 13.3.3.2). 1431ImplicitConversionSequence::CompareKind 1432Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1433 const ImplicitConversionSequence& ICS2) 1434{ 1435 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1436 // conversion sequences (as defined in 13.3.3.1) 1437 // -- a standard conversion sequence (13.3.3.1.1) is a better 1438 // conversion sequence than a user-defined conversion sequence or 1439 // an ellipsis conversion sequence, and 1440 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1441 // conversion sequence than an ellipsis conversion sequence 1442 // (13.3.3.1.3). 1443 // 1444 if (ICS1.ConversionKind < ICS2.ConversionKind) 1445 return ImplicitConversionSequence::Better; 1446 else if (ICS2.ConversionKind < ICS1.ConversionKind) 1447 return ImplicitConversionSequence::Worse; 1448 1449 // Two implicit conversion sequences of the same form are 1450 // indistinguishable conversion sequences unless one of the 1451 // following rules apply: (C++ 13.3.3.2p3): 1452 if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion) 1453 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1454 else if (ICS1.ConversionKind == 1455 ImplicitConversionSequence::UserDefinedConversion) { 1456 // User-defined conversion sequence U1 is a better conversion 1457 // sequence than another user-defined conversion sequence U2 if 1458 // they contain the same user-defined conversion function or 1459 // constructor and if the second standard conversion sequence of 1460 // U1 is better than the second standard conversion sequence of 1461 // U2 (C++ 13.3.3.2p3). 1462 if (ICS1.UserDefined.ConversionFunction == 1463 ICS2.UserDefined.ConversionFunction) 1464 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1465 ICS2.UserDefined.After); 1466 } 1467 1468 return ImplicitConversionSequence::Indistinguishable; 1469} 1470 1471/// CompareStandardConversionSequences - Compare two standard 1472/// conversion sequences to determine whether one is better than the 1473/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1474ImplicitConversionSequence::CompareKind 1475Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1476 const StandardConversionSequence& SCS2) 1477{ 1478 // Standard conversion sequence S1 is a better conversion sequence 1479 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1480 1481 // -- S1 is a proper subsequence of S2 (comparing the conversion 1482 // sequences in the canonical form defined by 13.3.3.1.1, 1483 // excluding any Lvalue Transformation; the identity conversion 1484 // sequence is considered to be a subsequence of any 1485 // non-identity conversion sequence) or, if not that, 1486 if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third) 1487 // Neither is a proper subsequence of the other. Do nothing. 1488 ; 1489 else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) || 1490 (SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) || 1491 (SCS1.Second == ICK_Identity && 1492 SCS1.Third == ICK_Identity)) 1493 // SCS1 is a proper subsequence of SCS2. 1494 return ImplicitConversionSequence::Better; 1495 else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) || 1496 (SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) || 1497 (SCS2.Second == ICK_Identity && 1498 SCS2.Third == ICK_Identity)) 1499 // SCS2 is a proper subsequence of SCS1. 1500 return ImplicitConversionSequence::Worse; 1501 1502 // -- the rank of S1 is better than the rank of S2 (by the rules 1503 // defined below), or, if not that, 1504 ImplicitConversionRank Rank1 = SCS1.getRank(); 1505 ImplicitConversionRank Rank2 = SCS2.getRank(); 1506 if (Rank1 < Rank2) 1507 return ImplicitConversionSequence::Better; 1508 else if (Rank2 < Rank1) 1509 return ImplicitConversionSequence::Worse; 1510 1511 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1512 // are indistinguishable unless one of the following rules 1513 // applies: 1514 1515 // A conversion that is not a conversion of a pointer, or 1516 // pointer to member, to bool is better than another conversion 1517 // that is such a conversion. 1518 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1519 return SCS2.isPointerConversionToBool() 1520 ? ImplicitConversionSequence::Better 1521 : ImplicitConversionSequence::Worse; 1522 1523 // C++ [over.ics.rank]p4b2: 1524 // 1525 // If class B is derived directly or indirectly from class A, 1526 // conversion of B* to A* is better than conversion of B* to 1527 // void*, and conversion of A* to void* is better than conversion 1528 // of B* to void*. 1529 bool SCS1ConvertsToVoid 1530 = SCS1.isPointerConversionToVoidPointer(Context); 1531 bool SCS2ConvertsToVoid 1532 = SCS2.isPointerConversionToVoidPointer(Context); 1533 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1534 // Exactly one of the conversion sequences is a conversion to 1535 // a void pointer; it's the worse conversion. 1536 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1537 : ImplicitConversionSequence::Worse; 1538 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1539 // Neither conversion sequence converts to a void pointer; compare 1540 // their derived-to-base conversions. 1541 if (ImplicitConversionSequence::CompareKind DerivedCK 1542 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1543 return DerivedCK; 1544 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1545 // Both conversion sequences are conversions to void 1546 // pointers. Compare the source types to determine if there's an 1547 // inheritance relationship in their sources. 1548 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1549 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1550 1551 // Adjust the types we're converting from via the array-to-pointer 1552 // conversion, if we need to. 1553 if (SCS1.First == ICK_Array_To_Pointer) 1554 FromType1 = Context.getArrayDecayedType(FromType1); 1555 if (SCS2.First == ICK_Array_To_Pointer) 1556 FromType2 = Context.getArrayDecayedType(FromType2); 1557 1558 QualType FromPointee1 1559 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1560 QualType FromPointee2 1561 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1562 1563 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1564 return ImplicitConversionSequence::Better; 1565 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1566 return ImplicitConversionSequence::Worse; 1567 1568 // Objective-C++: If one interface is more specific than the 1569 // other, it is the better one. 1570 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1571 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1572 if (FromIface1 && FromIface1) { 1573 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1574 return ImplicitConversionSequence::Better; 1575 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1576 return ImplicitConversionSequence::Worse; 1577 } 1578 } 1579 1580 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1581 // bullet 3). 1582 if (ImplicitConversionSequence::CompareKind QualCK 1583 = CompareQualificationConversions(SCS1, SCS2)) 1584 return QualCK; 1585 1586 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 1587 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1588 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1589 // C++0x [over.ics.rank]p3b4: 1590 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an 1591 // implicit object parameter of a non-static member function declared 1592 // without a ref-qualifier, and S1 binds an rvalue reference to an 1593 // rvalue and S2 binds an lvalue reference. 1594 // FIXME: We have far too little information for this check. We don't know 1595 // if the bound object is an rvalue. We don't know if the binding type is 1596 // an rvalue or lvalue reference. We don't know if we're dealing with the 1597 // implicit object parameter, or if the member function in this case has 1598 // a ref qualifier. 1599 1600 // C++ [over.ics.rank]p3b4: 1601 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1602 // which the references refer are the same type except for 1603 // top-level cv-qualifiers, and the type to which the reference 1604 // initialized by S2 refers is more cv-qualified than the type 1605 // to which the reference initialized by S1 refers. 1606 T1 = Context.getCanonicalType(T1); 1607 T2 = Context.getCanonicalType(T2); 1608 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) { 1609 if (T2.isMoreQualifiedThan(T1)) 1610 return ImplicitConversionSequence::Better; 1611 else if (T1.isMoreQualifiedThan(T2)) 1612 return ImplicitConversionSequence::Worse; 1613 } 1614 } 1615 1616 return ImplicitConversionSequence::Indistinguishable; 1617} 1618 1619/// CompareQualificationConversions - Compares two standard conversion 1620/// sequences to determine whether they can be ranked based on their 1621/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1622ImplicitConversionSequence::CompareKind 1623Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1624 const StandardConversionSequence& SCS2) 1625{ 1626 // C++ 13.3.3.2p3: 1627 // -- S1 and S2 differ only in their qualification conversion and 1628 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1629 // cv-qualification signature of type T1 is a proper subset of 1630 // the cv-qualification signature of type T2, and S1 is not the 1631 // deprecated string literal array-to-pointer conversion (4.2). 1632 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1633 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1634 return ImplicitConversionSequence::Indistinguishable; 1635 1636 // FIXME: the example in the standard doesn't use a qualification 1637 // conversion (!) 1638 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1639 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1640 T1 = Context.getCanonicalType(T1); 1641 T2 = Context.getCanonicalType(T2); 1642 1643 // If the types are the same, we won't learn anything by unwrapped 1644 // them. 1645 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1646 return ImplicitConversionSequence::Indistinguishable; 1647 1648 ImplicitConversionSequence::CompareKind Result 1649 = ImplicitConversionSequence::Indistinguishable; 1650 while (UnwrapSimilarPointerTypes(T1, T2)) { 1651 // Within each iteration of the loop, we check the qualifiers to 1652 // determine if this still looks like a qualification 1653 // conversion. Then, if all is well, we unwrap one more level of 1654 // pointers or pointers-to-members and do it all again 1655 // until there are no more pointers or pointers-to-members left 1656 // to unwrap. This essentially mimics what 1657 // IsQualificationConversion does, but here we're checking for a 1658 // strict subset of qualifiers. 1659 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1660 // The qualifiers are the same, so this doesn't tell us anything 1661 // about how the sequences rank. 1662 ; 1663 else if (T2.isMoreQualifiedThan(T1)) { 1664 // T1 has fewer qualifiers, so it could be the better sequence. 1665 if (Result == ImplicitConversionSequence::Worse) 1666 // Neither has qualifiers that are a subset of the other's 1667 // qualifiers. 1668 return ImplicitConversionSequence::Indistinguishable; 1669 1670 Result = ImplicitConversionSequence::Better; 1671 } else if (T1.isMoreQualifiedThan(T2)) { 1672 // T2 has fewer qualifiers, so it could be the better sequence. 1673 if (Result == ImplicitConversionSequence::Better) 1674 // Neither has qualifiers that are a subset of the other's 1675 // qualifiers. 1676 return ImplicitConversionSequence::Indistinguishable; 1677 1678 Result = ImplicitConversionSequence::Worse; 1679 } else { 1680 // Qualifiers are disjoint. 1681 return ImplicitConversionSequence::Indistinguishable; 1682 } 1683 1684 // If the types after this point are equivalent, we're done. 1685 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1686 break; 1687 } 1688 1689 // Check that the winning standard conversion sequence isn't using 1690 // the deprecated string literal array to pointer conversion. 1691 switch (Result) { 1692 case ImplicitConversionSequence::Better: 1693 if (SCS1.Deprecated) 1694 Result = ImplicitConversionSequence::Indistinguishable; 1695 break; 1696 1697 case ImplicitConversionSequence::Indistinguishable: 1698 break; 1699 1700 case ImplicitConversionSequence::Worse: 1701 if (SCS2.Deprecated) 1702 Result = ImplicitConversionSequence::Indistinguishable; 1703 break; 1704 } 1705 1706 return Result; 1707} 1708 1709/// CompareDerivedToBaseConversions - Compares two standard conversion 1710/// sequences to determine whether they can be ranked based on their 1711/// various kinds of derived-to-base conversions (C++ 1712/// [over.ics.rank]p4b3). As part of these checks, we also look at 1713/// conversions between Objective-C interface types. 1714ImplicitConversionSequence::CompareKind 1715Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 1716 const StandardConversionSequence& SCS2) { 1717 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1718 QualType ToType1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1719 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1720 QualType ToType2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1721 1722 // Adjust the types we're converting from via the array-to-pointer 1723 // conversion, if we need to. 1724 if (SCS1.First == ICK_Array_To_Pointer) 1725 FromType1 = Context.getArrayDecayedType(FromType1); 1726 if (SCS2.First == ICK_Array_To_Pointer) 1727 FromType2 = Context.getArrayDecayedType(FromType2); 1728 1729 // Canonicalize all of the types. 1730 FromType1 = Context.getCanonicalType(FromType1); 1731 ToType1 = Context.getCanonicalType(ToType1); 1732 FromType2 = Context.getCanonicalType(FromType2); 1733 ToType2 = Context.getCanonicalType(ToType2); 1734 1735 // C++ [over.ics.rank]p4b3: 1736 // 1737 // If class B is derived directly or indirectly from class A and 1738 // class C is derived directly or indirectly from B, 1739 // 1740 // For Objective-C, we let A, B, and C also be Objective-C 1741 // interfaces. 1742 1743 // Compare based on pointer conversions. 1744 if (SCS1.Second == ICK_Pointer_Conversion && 1745 SCS2.Second == ICK_Pointer_Conversion && 1746 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 1747 FromType1->isPointerType() && FromType2->isPointerType() && 1748 ToType1->isPointerType() && ToType2->isPointerType()) { 1749 QualType FromPointee1 1750 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1751 QualType ToPointee1 1752 = ToType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1753 QualType FromPointee2 1754 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1755 QualType ToPointee2 1756 = ToType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1757 1758 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1759 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1760 const ObjCInterfaceType* ToIface1 = ToPointee1->getAsObjCInterfaceType(); 1761 const ObjCInterfaceType* ToIface2 = ToPointee2->getAsObjCInterfaceType(); 1762 1763 // -- conversion of C* to B* is better than conversion of C* to A*, 1764 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 1765 if (IsDerivedFrom(ToPointee1, ToPointee2)) 1766 return ImplicitConversionSequence::Better; 1767 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 1768 return ImplicitConversionSequence::Worse; 1769 1770 if (ToIface1 && ToIface2) { 1771 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 1772 return ImplicitConversionSequence::Better; 1773 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 1774 return ImplicitConversionSequence::Worse; 1775 } 1776 } 1777 1778 // -- conversion of B* to A* is better than conversion of C* to A*, 1779 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 1780 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1781 return ImplicitConversionSequence::Better; 1782 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1783 return ImplicitConversionSequence::Worse; 1784 1785 if (FromIface1 && FromIface2) { 1786 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1787 return ImplicitConversionSequence::Better; 1788 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1789 return ImplicitConversionSequence::Worse; 1790 } 1791 } 1792 } 1793 1794 // Compare based on reference bindings. 1795 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding && 1796 SCS1.Second == ICK_Derived_To_Base) { 1797 // -- binding of an expression of type C to a reference of type 1798 // B& is better than binding an expression of type C to a 1799 // reference of type A&, 1800 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1801 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1802 if (IsDerivedFrom(ToType1, ToType2)) 1803 return ImplicitConversionSequence::Better; 1804 else if (IsDerivedFrom(ToType2, ToType1)) 1805 return ImplicitConversionSequence::Worse; 1806 } 1807 1808 // -- binding of an expression of type B to a reference of type 1809 // A& is better than binding an expression of type C to a 1810 // reference of type A&, 1811 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1812 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1813 if (IsDerivedFrom(FromType2, FromType1)) 1814 return ImplicitConversionSequence::Better; 1815 else if (IsDerivedFrom(FromType1, FromType2)) 1816 return ImplicitConversionSequence::Worse; 1817 } 1818 } 1819 1820 1821 // FIXME: conversion of A::* to B::* is better than conversion of 1822 // A::* to C::*, 1823 1824 // FIXME: conversion of B::* to C::* is better than conversion of 1825 // A::* to C::*, and 1826 1827 if (SCS1.CopyConstructor && SCS2.CopyConstructor && 1828 SCS1.Second == ICK_Derived_To_Base) { 1829 // -- conversion of C to B is better than conversion of C to A, 1830 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1831 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1832 if (IsDerivedFrom(ToType1, ToType2)) 1833 return ImplicitConversionSequence::Better; 1834 else if (IsDerivedFrom(ToType2, ToType1)) 1835 return ImplicitConversionSequence::Worse; 1836 } 1837 1838 // -- conversion of B to A is better than conversion of C to A. 1839 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1840 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1841 if (IsDerivedFrom(FromType2, FromType1)) 1842 return ImplicitConversionSequence::Better; 1843 else if (IsDerivedFrom(FromType1, FromType2)) 1844 return ImplicitConversionSequence::Worse; 1845 } 1846 } 1847 1848 return ImplicitConversionSequence::Indistinguishable; 1849} 1850 1851/// TryCopyInitialization - Try to copy-initialize a value of type 1852/// ToType from the expression From. Return the implicit conversion 1853/// sequence required to pass this argument, which may be a bad 1854/// conversion sequence (meaning that the argument cannot be passed to 1855/// a parameter of this type). If @p SuppressUserConversions, then we 1856/// do not permit any user-defined conversion sequences. 1857ImplicitConversionSequence 1858Sema::TryCopyInitialization(Expr *From, QualType ToType, 1859 bool SuppressUserConversions) { 1860 if (ToType->isReferenceType()) { 1861 ImplicitConversionSequence ICS; 1862 CheckReferenceInit(From, ToType, &ICS, SuppressUserConversions); 1863 return ICS; 1864 } else { 1865 return TryImplicitConversion(From, ToType, SuppressUserConversions); 1866 } 1867} 1868 1869/// PerformArgumentPassing - Pass the argument Arg into a parameter of 1870/// type ToType. Returns true (and emits a diagnostic) if there was 1871/// an error, returns false if the initialization succeeded. 1872bool Sema::PerformCopyInitialization(Expr *&From, QualType ToType, 1873 const char* Flavor) { 1874 if (!getLangOptions().CPlusPlus) { 1875 // In C, argument passing is the same as performing an assignment. 1876 QualType FromType = From->getType(); 1877 AssignConvertType ConvTy = 1878 CheckSingleAssignmentConstraints(ToType, From); 1879 1880 return DiagnoseAssignmentResult(ConvTy, From->getLocStart(), ToType, 1881 FromType, From, Flavor); 1882 } 1883 1884 if (ToType->isReferenceType()) 1885 return CheckReferenceInit(From, ToType); 1886 1887 if (!PerformImplicitConversion(From, ToType, Flavor)) 1888 return false; 1889 1890 return Diag(From->getSourceRange().getBegin(), 1891 diag::err_typecheck_convert_incompatible) 1892 << ToType << From->getType() << Flavor << From->getSourceRange(); 1893} 1894 1895/// TryObjectArgumentInitialization - Try to initialize the object 1896/// parameter of the given member function (@c Method) from the 1897/// expression @p From. 1898ImplicitConversionSequence 1899Sema::TryObjectArgumentInitialization(Expr *From, CXXMethodDecl *Method) { 1900 QualType ClassType = Context.getTypeDeclType(Method->getParent()); 1901 unsigned MethodQuals = Method->getTypeQualifiers(); 1902 QualType ImplicitParamType = ClassType.getQualifiedType(MethodQuals); 1903 1904 // Set up the conversion sequence as a "bad" conversion, to allow us 1905 // to exit early. 1906 ImplicitConversionSequence ICS; 1907 ICS.Standard.setAsIdentityConversion(); 1908 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 1909 1910 // We need to have an object of class type. 1911 QualType FromType = From->getType(); 1912 if (!FromType->isRecordType()) 1913 return ICS; 1914 1915 // The implicit object parmeter is has the type "reference to cv X", 1916 // where X is the class of which the function is a member 1917 // (C++ [over.match.funcs]p4). However, when finding an implicit 1918 // conversion sequence for the argument, we are not allowed to 1919 // create temporaries or perform user-defined conversions 1920 // (C++ [over.match.funcs]p5). We perform a simplified version of 1921 // reference binding here, that allows class rvalues to bind to 1922 // non-constant references. 1923 1924 // First check the qualifiers. We don't care about lvalue-vs-rvalue 1925 // with the implicit object parameter (C++ [over.match.funcs]p5). 1926 QualType FromTypeCanon = Context.getCanonicalType(FromType); 1927 if (ImplicitParamType.getCVRQualifiers() != FromType.getCVRQualifiers() && 1928 !ImplicitParamType.isAtLeastAsQualifiedAs(FromType)) 1929 return ICS; 1930 1931 // Check that we have either the same type or a derived type. It 1932 // affects the conversion rank. 1933 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 1934 if (ClassTypeCanon == FromTypeCanon.getUnqualifiedType()) 1935 ICS.Standard.Second = ICK_Identity; 1936 else if (IsDerivedFrom(FromType, ClassType)) 1937 ICS.Standard.Second = ICK_Derived_To_Base; 1938 else 1939 return ICS; 1940 1941 // Success. Mark this as a reference binding. 1942 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 1943 ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr(); 1944 ICS.Standard.ToTypePtr = ImplicitParamType.getAsOpaquePtr(); 1945 ICS.Standard.ReferenceBinding = true; 1946 ICS.Standard.DirectBinding = true; 1947 return ICS; 1948} 1949 1950/// PerformObjectArgumentInitialization - Perform initialization of 1951/// the implicit object parameter for the given Method with the given 1952/// expression. 1953bool 1954Sema::PerformObjectArgumentInitialization(Expr *&From, CXXMethodDecl *Method) { 1955 QualType ImplicitParamType 1956 = Method->getThisType(Context)->getAsPointerType()->getPointeeType(); 1957 ImplicitConversionSequence ICS 1958 = TryObjectArgumentInitialization(From, Method); 1959 if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) 1960 return Diag(From->getSourceRange().getBegin(), 1961 diag::err_implicit_object_parameter_init) 1962 << ImplicitParamType << From->getType() << From->getSourceRange(); 1963 1964 if (ICS.Standard.Second == ICK_Derived_To_Base && 1965 CheckDerivedToBaseConversion(From->getType(), ImplicitParamType, 1966 From->getSourceRange().getBegin(), 1967 From->getSourceRange())) 1968 return true; 1969 1970 ImpCastExprToType(From, ImplicitParamType, /*isLvalue=*/true); 1971 return false; 1972} 1973 1974/// TryContextuallyConvertToBool - Attempt to contextually convert the 1975/// expression From to bool (C++0x [conv]p3). 1976ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 1977 return TryImplicitConversion(From, Context.BoolTy, false, true); 1978} 1979 1980/// PerformContextuallyConvertToBool - Perform a contextual conversion 1981/// of the expression From to bool (C++0x [conv]p3). 1982bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 1983 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 1984 if (!PerformImplicitConversion(From, Context.BoolTy, ICS, "converting")) 1985 return false; 1986 1987 return Diag(From->getSourceRange().getBegin(), 1988 diag::err_typecheck_bool_condition) 1989 << From->getType() << From->getSourceRange(); 1990} 1991 1992/// AddOverloadCandidate - Adds the given function to the set of 1993/// candidate functions, using the given function call arguments. If 1994/// @p SuppressUserConversions, then don't allow user-defined 1995/// conversions via constructors or conversion operators. 1996void 1997Sema::AddOverloadCandidate(FunctionDecl *Function, 1998 Expr **Args, unsigned NumArgs, 1999 OverloadCandidateSet& CandidateSet, 2000 bool SuppressUserConversions) 2001{ 2002 const FunctionProtoType* Proto 2003 = dyn_cast<FunctionProtoType>(Function->getType()->getAsFunctionType()); 2004 assert(Proto && "Functions without a prototype cannot be overloaded"); 2005 assert(!isa<CXXConversionDecl>(Function) && 2006 "Use AddConversionCandidate for conversion functions"); 2007 2008 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2009 // If we get here, it's because we're calling a member function 2010 // that is named without a member access expression (e.g., 2011 // "this->f") that was either written explicitly or created 2012 // implicitly. This can happen with a qualified call to a member 2013 // function, e.g., X::f(). We use a NULL object as the implied 2014 // object argument (C++ [over.call.func]p3). 2015 AddMethodCandidate(Method, 0, Args, NumArgs, CandidateSet, 2016 SuppressUserConversions); 2017 return; 2018 } 2019 2020 2021 // Add this candidate 2022 CandidateSet.push_back(OverloadCandidate()); 2023 OverloadCandidate& Candidate = CandidateSet.back(); 2024 Candidate.Function = Function; 2025 Candidate.Viable = true; 2026 Candidate.IsSurrogate = false; 2027 Candidate.IgnoreObjectArgument = false; 2028 2029 unsigned NumArgsInProto = Proto->getNumArgs(); 2030 2031 // (C++ 13.3.2p2): A candidate function having fewer than m 2032 // parameters is viable only if it has an ellipsis in its parameter 2033 // list (8.3.5). 2034 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2035 Candidate.Viable = false; 2036 return; 2037 } 2038 2039 // (C++ 13.3.2p2): A candidate function having more than m parameters 2040 // is viable only if the (m+1)st parameter has a default argument 2041 // (8.3.6). For the purposes of overload resolution, the 2042 // parameter list is truncated on the right, so that there are 2043 // exactly m parameters. 2044 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2045 if (NumArgs < MinRequiredArgs) { 2046 // Not enough arguments. 2047 Candidate.Viable = false; 2048 return; 2049 } 2050 2051 // Determine the implicit conversion sequences for each of the 2052 // arguments. 2053 Candidate.Conversions.resize(NumArgs); 2054 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2055 if (ArgIdx < NumArgsInProto) { 2056 // (C++ 13.3.2p3): for F to be a viable function, there shall 2057 // exist for each argument an implicit conversion sequence 2058 // (13.3.3.1) that converts that argument to the corresponding 2059 // parameter of F. 2060 QualType ParamType = Proto->getArgType(ArgIdx); 2061 Candidate.Conversions[ArgIdx] 2062 = TryCopyInitialization(Args[ArgIdx], ParamType, 2063 SuppressUserConversions); 2064 if (Candidate.Conversions[ArgIdx].ConversionKind 2065 == ImplicitConversionSequence::BadConversion) { 2066 Candidate.Viable = false; 2067 break; 2068 } 2069 } else { 2070 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2071 // argument for which there is no corresponding parameter is 2072 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2073 Candidate.Conversions[ArgIdx].ConversionKind 2074 = ImplicitConversionSequence::EllipsisConversion; 2075 } 2076 } 2077} 2078 2079/// \brief Add all of the function declarations in the given function set to 2080/// the overload canddiate set. 2081void Sema::AddFunctionCandidates(const FunctionSet &Functions, 2082 Expr **Args, unsigned NumArgs, 2083 OverloadCandidateSet& CandidateSet, 2084 bool SuppressUserConversions) { 2085 for (FunctionSet::const_iterator F = Functions.begin(), 2086 FEnd = Functions.end(); 2087 F != FEnd; ++F) 2088 AddOverloadCandidate(*F, Args, NumArgs, CandidateSet, 2089 SuppressUserConversions); 2090} 2091 2092/// AddMethodCandidate - Adds the given C++ member function to the set 2093/// of candidate functions, using the given function call arguments 2094/// and the object argument (@c Object). For example, in a call 2095/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2096/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2097/// allow user-defined conversions via constructors or conversion 2098/// operators. 2099void 2100Sema::AddMethodCandidate(CXXMethodDecl *Method, Expr *Object, 2101 Expr **Args, unsigned NumArgs, 2102 OverloadCandidateSet& CandidateSet, 2103 bool SuppressUserConversions) 2104{ 2105 const FunctionProtoType* Proto 2106 = dyn_cast<FunctionProtoType>(Method->getType()->getAsFunctionType()); 2107 assert(Proto && "Methods without a prototype cannot be overloaded"); 2108 assert(!isa<CXXConversionDecl>(Method) && 2109 "Use AddConversionCandidate for conversion functions"); 2110 2111 // Add this candidate 2112 CandidateSet.push_back(OverloadCandidate()); 2113 OverloadCandidate& Candidate = CandidateSet.back(); 2114 Candidate.Function = Method; 2115 Candidate.IsSurrogate = false; 2116 Candidate.IgnoreObjectArgument = false; 2117 2118 unsigned NumArgsInProto = Proto->getNumArgs(); 2119 2120 // (C++ 13.3.2p2): A candidate function having fewer than m 2121 // parameters is viable only if it has an ellipsis in its parameter 2122 // list (8.3.5). 2123 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2124 Candidate.Viable = false; 2125 return; 2126 } 2127 2128 // (C++ 13.3.2p2): A candidate function having more than m parameters 2129 // is viable only if the (m+1)st parameter has a default argument 2130 // (8.3.6). For the purposes of overload resolution, the 2131 // parameter list is truncated on the right, so that there are 2132 // exactly m parameters. 2133 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2134 if (NumArgs < MinRequiredArgs) { 2135 // Not enough arguments. 2136 Candidate.Viable = false; 2137 return; 2138 } 2139 2140 Candidate.Viable = true; 2141 Candidate.Conversions.resize(NumArgs + 1); 2142 2143 if (Method->isStatic() || !Object) 2144 // The implicit object argument is ignored. 2145 Candidate.IgnoreObjectArgument = true; 2146 else { 2147 // Determine the implicit conversion sequence for the object 2148 // parameter. 2149 Candidate.Conversions[0] = TryObjectArgumentInitialization(Object, Method); 2150 if (Candidate.Conversions[0].ConversionKind 2151 == ImplicitConversionSequence::BadConversion) { 2152 Candidate.Viable = false; 2153 return; 2154 } 2155 } 2156 2157 // Determine the implicit conversion sequences for each of the 2158 // arguments. 2159 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2160 if (ArgIdx < NumArgsInProto) { 2161 // (C++ 13.3.2p3): for F to be a viable function, there shall 2162 // exist for each argument an implicit conversion sequence 2163 // (13.3.3.1) that converts that argument to the corresponding 2164 // parameter of F. 2165 QualType ParamType = Proto->getArgType(ArgIdx); 2166 Candidate.Conversions[ArgIdx + 1] 2167 = TryCopyInitialization(Args[ArgIdx], ParamType, 2168 SuppressUserConversions); 2169 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2170 == ImplicitConversionSequence::BadConversion) { 2171 Candidate.Viable = false; 2172 break; 2173 } 2174 } else { 2175 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2176 // argument for which there is no corresponding parameter is 2177 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2178 Candidate.Conversions[ArgIdx + 1].ConversionKind 2179 = ImplicitConversionSequence::EllipsisConversion; 2180 } 2181 } 2182} 2183 2184/// AddConversionCandidate - Add a C++ conversion function as a 2185/// candidate in the candidate set (C++ [over.match.conv], 2186/// C++ [over.match.copy]). From is the expression we're converting from, 2187/// and ToType is the type that we're eventually trying to convert to 2188/// (which may or may not be the same type as the type that the 2189/// conversion function produces). 2190void 2191Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 2192 Expr *From, QualType ToType, 2193 OverloadCandidateSet& CandidateSet) { 2194 // Add this candidate 2195 CandidateSet.push_back(OverloadCandidate()); 2196 OverloadCandidate& Candidate = CandidateSet.back(); 2197 Candidate.Function = Conversion; 2198 Candidate.IsSurrogate = false; 2199 Candidate.IgnoreObjectArgument = false; 2200 Candidate.FinalConversion.setAsIdentityConversion(); 2201 Candidate.FinalConversion.FromTypePtr 2202 = Conversion->getConversionType().getAsOpaquePtr(); 2203 Candidate.FinalConversion.ToTypePtr = ToType.getAsOpaquePtr(); 2204 2205 // Determine the implicit conversion sequence for the implicit 2206 // object parameter. 2207 Candidate.Viable = true; 2208 Candidate.Conversions.resize(1); 2209 Candidate.Conversions[0] = TryObjectArgumentInitialization(From, Conversion); 2210 2211 if (Candidate.Conversions[0].ConversionKind 2212 == ImplicitConversionSequence::BadConversion) { 2213 Candidate.Viable = false; 2214 return; 2215 } 2216 2217 // To determine what the conversion from the result of calling the 2218 // conversion function to the type we're eventually trying to 2219 // convert to (ToType), we need to synthesize a call to the 2220 // conversion function and attempt copy initialization from it. This 2221 // makes sure that we get the right semantics with respect to 2222 // lvalues/rvalues and the type. Fortunately, we can allocate this 2223 // call on the stack and we don't need its arguments to be 2224 // well-formed. 2225 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 2226 SourceLocation()); 2227 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 2228 &ConversionRef, false); 2229 2230 // Note that it is safe to allocate CallExpr on the stack here because 2231 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 2232 // allocator). 2233 CallExpr Call(Context, &ConversionFn, 0, 0, 2234 Conversion->getConversionType().getNonReferenceType(), 2235 SourceLocation()); 2236 ImplicitConversionSequence ICS = TryCopyInitialization(&Call, ToType, true); 2237 switch (ICS.ConversionKind) { 2238 case ImplicitConversionSequence::StandardConversion: 2239 Candidate.FinalConversion = ICS.Standard; 2240 break; 2241 2242 case ImplicitConversionSequence::BadConversion: 2243 Candidate.Viable = false; 2244 break; 2245 2246 default: 2247 assert(false && 2248 "Can only end up with a standard conversion sequence or failure"); 2249 } 2250} 2251 2252/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 2253/// converts the given @c Object to a function pointer via the 2254/// conversion function @c Conversion, and then attempts to call it 2255/// with the given arguments (C++ [over.call.object]p2-4). Proto is 2256/// the type of function that we'll eventually be calling. 2257void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 2258 const FunctionProtoType *Proto, 2259 Expr *Object, Expr **Args, unsigned NumArgs, 2260 OverloadCandidateSet& CandidateSet) { 2261 CandidateSet.push_back(OverloadCandidate()); 2262 OverloadCandidate& Candidate = CandidateSet.back(); 2263 Candidate.Function = 0; 2264 Candidate.Surrogate = Conversion; 2265 Candidate.Viable = true; 2266 Candidate.IsSurrogate = true; 2267 Candidate.IgnoreObjectArgument = false; 2268 Candidate.Conversions.resize(NumArgs + 1); 2269 2270 // Determine the implicit conversion sequence for the implicit 2271 // object parameter. 2272 ImplicitConversionSequence ObjectInit 2273 = TryObjectArgumentInitialization(Object, Conversion); 2274 if (ObjectInit.ConversionKind == ImplicitConversionSequence::BadConversion) { 2275 Candidate.Viable = false; 2276 return; 2277 } 2278 2279 // The first conversion is actually a user-defined conversion whose 2280 // first conversion is ObjectInit's standard conversion (which is 2281 // effectively a reference binding). Record it as such. 2282 Candidate.Conversions[0].ConversionKind 2283 = ImplicitConversionSequence::UserDefinedConversion; 2284 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 2285 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 2286 Candidate.Conversions[0].UserDefined.After 2287 = Candidate.Conversions[0].UserDefined.Before; 2288 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 2289 2290 // Find the 2291 unsigned NumArgsInProto = Proto->getNumArgs(); 2292 2293 // (C++ 13.3.2p2): A candidate function having fewer than m 2294 // parameters is viable only if it has an ellipsis in its parameter 2295 // list (8.3.5). 2296 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2297 Candidate.Viable = false; 2298 return; 2299 } 2300 2301 // Function types don't have any default arguments, so just check if 2302 // we have enough arguments. 2303 if (NumArgs < NumArgsInProto) { 2304 // Not enough arguments. 2305 Candidate.Viable = false; 2306 return; 2307 } 2308 2309 // Determine the implicit conversion sequences for each of the 2310 // arguments. 2311 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2312 if (ArgIdx < NumArgsInProto) { 2313 // (C++ 13.3.2p3): for F to be a viable function, there shall 2314 // exist for each argument an implicit conversion sequence 2315 // (13.3.3.1) that converts that argument to the corresponding 2316 // parameter of F. 2317 QualType ParamType = Proto->getArgType(ArgIdx); 2318 Candidate.Conversions[ArgIdx + 1] 2319 = TryCopyInitialization(Args[ArgIdx], ParamType, 2320 /*SuppressUserConversions=*/false); 2321 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2322 == ImplicitConversionSequence::BadConversion) { 2323 Candidate.Viable = false; 2324 break; 2325 } 2326 } else { 2327 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2328 // argument for which there is no corresponding parameter is 2329 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2330 Candidate.Conversions[ArgIdx + 1].ConversionKind 2331 = ImplicitConversionSequence::EllipsisConversion; 2332 } 2333 } 2334} 2335 2336// FIXME: This will eventually be removed, once we've migrated all of 2337// the operator overloading logic over to the scheme used by binary 2338// operators, which works for template instantiation. 2339void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 2340 SourceLocation OpLoc, 2341 Expr **Args, unsigned NumArgs, 2342 OverloadCandidateSet& CandidateSet, 2343 SourceRange OpRange) { 2344 2345 FunctionSet Functions; 2346 2347 QualType T1 = Args[0]->getType(); 2348 QualType T2; 2349 if (NumArgs > 1) 2350 T2 = Args[1]->getType(); 2351 2352 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2353 LookupOverloadedOperatorName(Op, S, T1, T2, Functions); 2354 ArgumentDependentLookup(OpName, Args, NumArgs, Functions); 2355 AddFunctionCandidates(Functions, Args, NumArgs, CandidateSet); 2356 AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange); 2357 AddBuiltinOperatorCandidates(Op, Args, NumArgs, CandidateSet); 2358} 2359 2360/// \brief Add overload candidates for overloaded operators that are 2361/// member functions. 2362/// 2363/// Add the overloaded operator candidates that are member functions 2364/// for the operator Op that was used in an operator expression such 2365/// as "x Op y". , Args/NumArgs provides the operator arguments, and 2366/// CandidateSet will store the added overload candidates. (C++ 2367/// [over.match.oper]). 2368void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 2369 SourceLocation OpLoc, 2370 Expr **Args, unsigned NumArgs, 2371 OverloadCandidateSet& CandidateSet, 2372 SourceRange OpRange) { 2373 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2374 2375 // C++ [over.match.oper]p3: 2376 // For a unary operator @ with an operand of a type whose 2377 // cv-unqualified version is T1, and for a binary operator @ with 2378 // a left operand of a type whose cv-unqualified version is T1 and 2379 // a right operand of a type whose cv-unqualified version is T2, 2380 // three sets of candidate functions, designated member 2381 // candidates, non-member candidates and built-in candidates, are 2382 // constructed as follows: 2383 QualType T1 = Args[0]->getType(); 2384 QualType T2; 2385 if (NumArgs > 1) 2386 T2 = Args[1]->getType(); 2387 2388 // -- If T1 is a class type, the set of member candidates is the 2389 // result of the qualified lookup of T1::operator@ 2390 // (13.3.1.1.1); otherwise, the set of member candidates is 2391 // empty. 2392 // FIXME: Lookup in base classes, too! 2393 if (const RecordType *T1Rec = T1->getAsRecordType()) { 2394 DeclContext::lookup_const_iterator Oper, OperEnd; 2395 for (llvm::tie(Oper, OperEnd) = T1Rec->getDecl()->lookup(OpName); 2396 Oper != OperEnd; ++Oper) 2397 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Args[0], 2398 Args+1, NumArgs - 1, CandidateSet, 2399 /*SuppressUserConversions=*/false); 2400 } 2401} 2402 2403/// AddBuiltinCandidate - Add a candidate for a built-in 2404/// operator. ResultTy and ParamTys are the result and parameter types 2405/// of the built-in candidate, respectively. Args and NumArgs are the 2406/// arguments being passed to the candidate. IsAssignmentOperator 2407/// should be true when this built-in candidate is an assignment 2408/// operator. NumContextualBoolArguments is the number of arguments 2409/// (at the beginning of the argument list) that will be contextually 2410/// converted to bool. 2411void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 2412 Expr **Args, unsigned NumArgs, 2413 OverloadCandidateSet& CandidateSet, 2414 bool IsAssignmentOperator, 2415 unsigned NumContextualBoolArguments) { 2416 // Add this candidate 2417 CandidateSet.push_back(OverloadCandidate()); 2418 OverloadCandidate& Candidate = CandidateSet.back(); 2419 Candidate.Function = 0; 2420 Candidate.IsSurrogate = false; 2421 Candidate.IgnoreObjectArgument = false; 2422 Candidate.BuiltinTypes.ResultTy = ResultTy; 2423 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2424 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 2425 2426 // Determine the implicit conversion sequences for each of the 2427 // arguments. 2428 Candidate.Viable = true; 2429 Candidate.Conversions.resize(NumArgs); 2430 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2431 // C++ [over.match.oper]p4: 2432 // For the built-in assignment operators, conversions of the 2433 // left operand are restricted as follows: 2434 // -- no temporaries are introduced to hold the left operand, and 2435 // -- no user-defined conversions are applied to the left 2436 // operand to achieve a type match with the left-most 2437 // parameter of a built-in candidate. 2438 // 2439 // We block these conversions by turning off user-defined 2440 // conversions, since that is the only way that initialization of 2441 // a reference to a non-class type can occur from something that 2442 // is not of the same type. 2443 if (ArgIdx < NumContextualBoolArguments) { 2444 assert(ParamTys[ArgIdx] == Context.BoolTy && 2445 "Contextual conversion to bool requires bool type"); 2446 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 2447 } else { 2448 Candidate.Conversions[ArgIdx] 2449 = TryCopyInitialization(Args[ArgIdx], ParamTys[ArgIdx], 2450 ArgIdx == 0 && IsAssignmentOperator); 2451 } 2452 if (Candidate.Conversions[ArgIdx].ConversionKind 2453 == ImplicitConversionSequence::BadConversion) { 2454 Candidate.Viable = false; 2455 break; 2456 } 2457 } 2458} 2459 2460/// BuiltinCandidateTypeSet - A set of types that will be used for the 2461/// candidate operator functions for built-in operators (C++ 2462/// [over.built]). The types are separated into pointer types and 2463/// enumeration types. 2464class BuiltinCandidateTypeSet { 2465 /// TypeSet - A set of types. 2466 typedef llvm::SmallPtrSet<void*, 8> TypeSet; 2467 2468 /// PointerTypes - The set of pointer types that will be used in the 2469 /// built-in candidates. 2470 TypeSet PointerTypes; 2471 2472 /// EnumerationTypes - The set of enumeration types that will be 2473 /// used in the built-in candidates. 2474 TypeSet EnumerationTypes; 2475 2476 /// Context - The AST context in which we will build the type sets. 2477 ASTContext &Context; 2478 2479 bool AddWithMoreQualifiedTypeVariants(QualType Ty); 2480 2481public: 2482 /// iterator - Iterates through the types that are part of the set. 2483 class iterator { 2484 TypeSet::iterator Base; 2485 2486 public: 2487 typedef QualType value_type; 2488 typedef QualType reference; 2489 typedef QualType pointer; 2490 typedef std::ptrdiff_t difference_type; 2491 typedef std::input_iterator_tag iterator_category; 2492 2493 iterator(TypeSet::iterator B) : Base(B) { } 2494 2495 iterator& operator++() { 2496 ++Base; 2497 return *this; 2498 } 2499 2500 iterator operator++(int) { 2501 iterator tmp(*this); 2502 ++(*this); 2503 return tmp; 2504 } 2505 2506 reference operator*() const { 2507 return QualType::getFromOpaquePtr(*Base); 2508 } 2509 2510 pointer operator->() const { 2511 return **this; 2512 } 2513 2514 friend bool operator==(iterator LHS, iterator RHS) { 2515 return LHS.Base == RHS.Base; 2516 } 2517 2518 friend bool operator!=(iterator LHS, iterator RHS) { 2519 return LHS.Base != RHS.Base; 2520 } 2521 }; 2522 2523 BuiltinCandidateTypeSet(ASTContext &Context) : Context(Context) { } 2524 2525 void AddTypesConvertedFrom(QualType Ty, bool AllowUserConversions, 2526 bool AllowExplicitConversions); 2527 2528 /// pointer_begin - First pointer type found; 2529 iterator pointer_begin() { return PointerTypes.begin(); } 2530 2531 /// pointer_end - Last pointer type found; 2532 iterator pointer_end() { return PointerTypes.end(); } 2533 2534 /// enumeration_begin - First enumeration type found; 2535 iterator enumeration_begin() { return EnumerationTypes.begin(); } 2536 2537 /// enumeration_end - Last enumeration type found; 2538 iterator enumeration_end() { return EnumerationTypes.end(); } 2539}; 2540 2541/// AddWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 2542/// the set of pointer types along with any more-qualified variants of 2543/// that type. For example, if @p Ty is "int const *", this routine 2544/// will add "int const *", "int const volatile *", "int const 2545/// restrict *", and "int const volatile restrict *" to the set of 2546/// pointer types. Returns true if the add of @p Ty itself succeeded, 2547/// false otherwise. 2548bool BuiltinCandidateTypeSet::AddWithMoreQualifiedTypeVariants(QualType Ty) { 2549 // Insert this type. 2550 if (!PointerTypes.insert(Ty.getAsOpaquePtr())) 2551 return false; 2552 2553 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2554 QualType PointeeTy = PointerTy->getPointeeType(); 2555 // FIXME: Optimize this so that we don't keep trying to add the same types. 2556 2557 // FIXME: Do we have to add CVR qualifiers at *all* levels to deal 2558 // with all pointer conversions that don't cast away constness? 2559 if (!PointeeTy.isConstQualified()) 2560 AddWithMoreQualifiedTypeVariants 2561 (Context.getPointerType(PointeeTy.withConst())); 2562 if (!PointeeTy.isVolatileQualified()) 2563 AddWithMoreQualifiedTypeVariants 2564 (Context.getPointerType(PointeeTy.withVolatile())); 2565 if (!PointeeTy.isRestrictQualified()) 2566 AddWithMoreQualifiedTypeVariants 2567 (Context.getPointerType(PointeeTy.withRestrict())); 2568 } 2569 2570 return true; 2571} 2572 2573/// AddTypesConvertedFrom - Add each of the types to which the type @p 2574/// Ty can be implicit converted to the given set of @p Types. We're 2575/// primarily interested in pointer types and enumeration types. 2576/// AllowUserConversions is true if we should look at the conversion 2577/// functions of a class type, and AllowExplicitConversions if we 2578/// should also include the explicit conversion functions of a class 2579/// type. 2580void 2581BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 2582 bool AllowUserConversions, 2583 bool AllowExplicitConversions) { 2584 // Only deal with canonical types. 2585 Ty = Context.getCanonicalType(Ty); 2586 2587 // Look through reference types; they aren't part of the type of an 2588 // expression for the purposes of conversions. 2589 if (const ReferenceType *RefTy = Ty->getAsReferenceType()) 2590 Ty = RefTy->getPointeeType(); 2591 2592 // We don't care about qualifiers on the type. 2593 Ty = Ty.getUnqualifiedType(); 2594 2595 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2596 QualType PointeeTy = PointerTy->getPointeeType(); 2597 2598 // Insert our type, and its more-qualified variants, into the set 2599 // of types. 2600 if (!AddWithMoreQualifiedTypeVariants(Ty)) 2601 return; 2602 2603 // Add 'cv void*' to our set of types. 2604 if (!Ty->isVoidType()) { 2605 QualType QualVoid 2606 = Context.VoidTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2607 AddWithMoreQualifiedTypeVariants(Context.getPointerType(QualVoid)); 2608 } 2609 2610 // If this is a pointer to a class type, add pointers to its bases 2611 // (with the same level of cv-qualification as the original 2612 // derived class, of course). 2613 if (const RecordType *PointeeRec = PointeeTy->getAsRecordType()) { 2614 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(PointeeRec->getDecl()); 2615 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 2616 Base != ClassDecl->bases_end(); ++Base) { 2617 QualType BaseTy = Context.getCanonicalType(Base->getType()); 2618 BaseTy = BaseTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2619 2620 // Add the pointer type, recursively, so that we get all of 2621 // the indirect base classes, too. 2622 AddTypesConvertedFrom(Context.getPointerType(BaseTy), false, false); 2623 } 2624 } 2625 } else if (Ty->isEnumeralType()) { 2626 EnumerationTypes.insert(Ty.getAsOpaquePtr()); 2627 } else if (AllowUserConversions) { 2628 if (const RecordType *TyRec = Ty->getAsRecordType()) { 2629 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 2630 // FIXME: Visit conversion functions in the base classes, too. 2631 OverloadedFunctionDecl *Conversions 2632 = ClassDecl->getConversionFunctions(); 2633 for (OverloadedFunctionDecl::function_iterator Func 2634 = Conversions->function_begin(); 2635 Func != Conversions->function_end(); ++Func) { 2636 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 2637 if (AllowExplicitConversions || !Conv->isExplicit()) 2638 AddTypesConvertedFrom(Conv->getConversionType(), false, false); 2639 } 2640 } 2641 } 2642} 2643 2644/// AddBuiltinOperatorCandidates - Add the appropriate built-in 2645/// operator overloads to the candidate set (C++ [over.built]), based 2646/// on the operator @p Op and the arguments given. For example, if the 2647/// operator is a binary '+', this routine might add "int 2648/// operator+(int, int)" to cover integer addition. 2649void 2650Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 2651 Expr **Args, unsigned NumArgs, 2652 OverloadCandidateSet& CandidateSet) { 2653 // The set of "promoted arithmetic types", which are the arithmetic 2654 // types are that preserved by promotion (C++ [over.built]p2). Note 2655 // that the first few of these types are the promoted integral 2656 // types; these types need to be first. 2657 // FIXME: What about complex? 2658 const unsigned FirstIntegralType = 0; 2659 const unsigned LastIntegralType = 13; 2660 const unsigned FirstPromotedIntegralType = 7, 2661 LastPromotedIntegralType = 13; 2662 const unsigned FirstPromotedArithmeticType = 7, 2663 LastPromotedArithmeticType = 16; 2664 const unsigned NumArithmeticTypes = 16; 2665 QualType ArithmeticTypes[NumArithmeticTypes] = { 2666 Context.BoolTy, Context.CharTy, Context.WCharTy, 2667 Context.SignedCharTy, Context.ShortTy, 2668 Context.UnsignedCharTy, Context.UnsignedShortTy, 2669 Context.IntTy, Context.LongTy, Context.LongLongTy, 2670 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 2671 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 2672 }; 2673 2674 // Find all of the types that the arguments can convert to, but only 2675 // if the operator we're looking at has built-in operator candidates 2676 // that make use of these types. 2677 BuiltinCandidateTypeSet CandidateTypes(Context); 2678 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 2679 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 2680 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 2681 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 2682 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 2683 (Op == OO_Star && NumArgs == 1)) { 2684 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2685 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 2686 true, 2687 (Op == OO_Exclaim || 2688 Op == OO_AmpAmp || 2689 Op == OO_PipePipe)); 2690 } 2691 2692 bool isComparison = false; 2693 switch (Op) { 2694 case OO_None: 2695 case NUM_OVERLOADED_OPERATORS: 2696 assert(false && "Expected an overloaded operator"); 2697 break; 2698 2699 case OO_Star: // '*' is either unary or binary 2700 if (NumArgs == 1) 2701 goto UnaryStar; 2702 else 2703 goto BinaryStar; 2704 break; 2705 2706 case OO_Plus: // '+' is either unary or binary 2707 if (NumArgs == 1) 2708 goto UnaryPlus; 2709 else 2710 goto BinaryPlus; 2711 break; 2712 2713 case OO_Minus: // '-' is either unary or binary 2714 if (NumArgs == 1) 2715 goto UnaryMinus; 2716 else 2717 goto BinaryMinus; 2718 break; 2719 2720 case OO_Amp: // '&' is either unary or binary 2721 if (NumArgs == 1) 2722 goto UnaryAmp; 2723 else 2724 goto BinaryAmp; 2725 2726 case OO_PlusPlus: 2727 case OO_MinusMinus: 2728 // C++ [over.built]p3: 2729 // 2730 // For every pair (T, VQ), where T is an arithmetic type, and VQ 2731 // is either volatile or empty, there exist candidate operator 2732 // functions of the form 2733 // 2734 // VQ T& operator++(VQ T&); 2735 // T operator++(VQ T&, int); 2736 // 2737 // C++ [over.built]p4: 2738 // 2739 // For every pair (T, VQ), where T is an arithmetic type other 2740 // than bool, and VQ is either volatile or empty, there exist 2741 // candidate operator functions of the form 2742 // 2743 // VQ T& operator--(VQ T&); 2744 // T operator--(VQ T&, int); 2745 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 2746 Arith < NumArithmeticTypes; ++Arith) { 2747 QualType ArithTy = ArithmeticTypes[Arith]; 2748 QualType ParamTypes[2] 2749 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 2750 2751 // Non-volatile version. 2752 if (NumArgs == 1) 2753 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2754 else 2755 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2756 2757 // Volatile version 2758 ParamTypes[0] = Context.getLValueReferenceType(ArithTy.withVolatile()); 2759 if (NumArgs == 1) 2760 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2761 else 2762 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2763 } 2764 2765 // C++ [over.built]p5: 2766 // 2767 // For every pair (T, VQ), where T is a cv-qualified or 2768 // cv-unqualified object type, and VQ is either volatile or 2769 // empty, there exist candidate operator functions of the form 2770 // 2771 // T*VQ& operator++(T*VQ&); 2772 // T*VQ& operator--(T*VQ&); 2773 // T* operator++(T*VQ&, int); 2774 // T* operator--(T*VQ&, int); 2775 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2776 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2777 // Skip pointer types that aren't pointers to object types. 2778 if (!(*Ptr)->getAsPointerType()->getPointeeType()->isObjectType()) 2779 continue; 2780 2781 QualType ParamTypes[2] = { 2782 Context.getLValueReferenceType(*Ptr), Context.IntTy 2783 }; 2784 2785 // Without volatile 2786 if (NumArgs == 1) 2787 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2788 else 2789 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2790 2791 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 2792 // With volatile 2793 ParamTypes[0] = Context.getLValueReferenceType((*Ptr).withVolatile()); 2794 if (NumArgs == 1) 2795 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2796 else 2797 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2798 } 2799 } 2800 break; 2801 2802 UnaryStar: 2803 // C++ [over.built]p6: 2804 // For every cv-qualified or cv-unqualified object type T, there 2805 // exist candidate operator functions of the form 2806 // 2807 // T& operator*(T*); 2808 // 2809 // C++ [over.built]p7: 2810 // For every function type T, there exist candidate operator 2811 // functions of the form 2812 // T& operator*(T*); 2813 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2814 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2815 QualType ParamTy = *Ptr; 2816 QualType PointeeTy = ParamTy->getAsPointerType()->getPointeeType(); 2817 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 2818 &ParamTy, Args, 1, CandidateSet); 2819 } 2820 break; 2821 2822 UnaryPlus: 2823 // C++ [over.built]p8: 2824 // For every type T, there exist candidate operator functions of 2825 // the form 2826 // 2827 // T* operator+(T*); 2828 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2829 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2830 QualType ParamTy = *Ptr; 2831 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 2832 } 2833 2834 // Fall through 2835 2836 UnaryMinus: 2837 // C++ [over.built]p9: 2838 // For every promoted arithmetic type T, there exist candidate 2839 // operator functions of the form 2840 // 2841 // T operator+(T); 2842 // T operator-(T); 2843 for (unsigned Arith = FirstPromotedArithmeticType; 2844 Arith < LastPromotedArithmeticType; ++Arith) { 2845 QualType ArithTy = ArithmeticTypes[Arith]; 2846 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 2847 } 2848 break; 2849 2850 case OO_Tilde: 2851 // C++ [over.built]p10: 2852 // For every promoted integral type T, there exist candidate 2853 // operator functions of the form 2854 // 2855 // T operator~(T); 2856 for (unsigned Int = FirstPromotedIntegralType; 2857 Int < LastPromotedIntegralType; ++Int) { 2858 QualType IntTy = ArithmeticTypes[Int]; 2859 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 2860 } 2861 break; 2862 2863 case OO_New: 2864 case OO_Delete: 2865 case OO_Array_New: 2866 case OO_Array_Delete: 2867 case OO_Call: 2868 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 2869 break; 2870 2871 case OO_Comma: 2872 UnaryAmp: 2873 case OO_Arrow: 2874 // C++ [over.match.oper]p3: 2875 // -- For the operator ',', the unary operator '&', or the 2876 // operator '->', the built-in candidates set is empty. 2877 break; 2878 2879 case OO_Less: 2880 case OO_Greater: 2881 case OO_LessEqual: 2882 case OO_GreaterEqual: 2883 case OO_EqualEqual: 2884 case OO_ExclaimEqual: 2885 // C++ [over.built]p15: 2886 // 2887 // For every pointer or enumeration type T, there exist 2888 // candidate operator functions of the form 2889 // 2890 // bool operator<(T, T); 2891 // bool operator>(T, T); 2892 // bool operator<=(T, T); 2893 // bool operator>=(T, T); 2894 // bool operator==(T, T); 2895 // bool operator!=(T, T); 2896 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2897 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2898 QualType ParamTypes[2] = { *Ptr, *Ptr }; 2899 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2900 } 2901 for (BuiltinCandidateTypeSet::iterator Enum 2902 = CandidateTypes.enumeration_begin(); 2903 Enum != CandidateTypes.enumeration_end(); ++Enum) { 2904 QualType ParamTypes[2] = { *Enum, *Enum }; 2905 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2906 } 2907 2908 // Fall through. 2909 isComparison = true; 2910 2911 BinaryPlus: 2912 BinaryMinus: 2913 if (!isComparison) { 2914 // We didn't fall through, so we must have OO_Plus or OO_Minus. 2915 2916 // C++ [over.built]p13: 2917 // 2918 // For every cv-qualified or cv-unqualified object type T 2919 // there exist candidate operator functions of the form 2920 // 2921 // T* operator+(T*, ptrdiff_t); 2922 // T& operator[](T*, ptrdiff_t); [BELOW] 2923 // T* operator-(T*, ptrdiff_t); 2924 // T* operator+(ptrdiff_t, T*); 2925 // T& operator[](ptrdiff_t, T*); [BELOW] 2926 // 2927 // C++ [over.built]p14: 2928 // 2929 // For every T, where T is a pointer to object type, there 2930 // exist candidate operator functions of the form 2931 // 2932 // ptrdiff_t operator-(T, T); 2933 for (BuiltinCandidateTypeSet::iterator Ptr 2934 = CandidateTypes.pointer_begin(); 2935 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2936 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 2937 2938 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 2939 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2940 2941 if (Op == OO_Plus) { 2942 // T* operator+(ptrdiff_t, T*); 2943 ParamTypes[0] = ParamTypes[1]; 2944 ParamTypes[1] = *Ptr; 2945 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2946 } else { 2947 // ptrdiff_t operator-(T, T); 2948 ParamTypes[1] = *Ptr; 2949 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 2950 Args, 2, CandidateSet); 2951 } 2952 } 2953 } 2954 // Fall through 2955 2956 case OO_Slash: 2957 BinaryStar: 2958 // C++ [over.built]p12: 2959 // 2960 // For every pair of promoted arithmetic types L and R, there 2961 // exist candidate operator functions of the form 2962 // 2963 // LR operator*(L, R); 2964 // LR operator/(L, R); 2965 // LR operator+(L, R); 2966 // LR operator-(L, R); 2967 // bool operator<(L, R); 2968 // bool operator>(L, R); 2969 // bool operator<=(L, R); 2970 // bool operator>=(L, R); 2971 // bool operator==(L, R); 2972 // bool operator!=(L, R); 2973 // 2974 // where LR is the result of the usual arithmetic conversions 2975 // between types L and R. 2976 for (unsigned Left = FirstPromotedArithmeticType; 2977 Left < LastPromotedArithmeticType; ++Left) { 2978 for (unsigned Right = FirstPromotedArithmeticType; 2979 Right < LastPromotedArithmeticType; ++Right) { 2980 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 2981 QualType Result 2982 = isComparison? Context.BoolTy 2983 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 2984 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 2985 } 2986 } 2987 break; 2988 2989 case OO_Percent: 2990 BinaryAmp: 2991 case OO_Caret: 2992 case OO_Pipe: 2993 case OO_LessLess: 2994 case OO_GreaterGreater: 2995 // C++ [over.built]p17: 2996 // 2997 // For every pair of promoted integral types L and R, there 2998 // exist candidate operator functions of the form 2999 // 3000 // LR operator%(L, R); 3001 // LR operator&(L, R); 3002 // LR operator^(L, R); 3003 // LR operator|(L, R); 3004 // L operator<<(L, R); 3005 // L operator>>(L, R); 3006 // 3007 // where LR is the result of the usual arithmetic conversions 3008 // between types L and R. 3009 for (unsigned Left = FirstPromotedIntegralType; 3010 Left < LastPromotedIntegralType; ++Left) { 3011 for (unsigned Right = FirstPromotedIntegralType; 3012 Right < LastPromotedIntegralType; ++Right) { 3013 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 3014 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 3015 ? LandR[0] 3016 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 3017 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 3018 } 3019 } 3020 break; 3021 3022 case OO_Equal: 3023 // C++ [over.built]p20: 3024 // 3025 // For every pair (T, VQ), where T is an enumeration or 3026 // (FIXME:) pointer to member type and VQ is either volatile or 3027 // empty, there exist candidate operator functions of the form 3028 // 3029 // VQ T& operator=(VQ T&, T); 3030 for (BuiltinCandidateTypeSet::iterator Enum 3031 = CandidateTypes.enumeration_begin(); 3032 Enum != CandidateTypes.enumeration_end(); ++Enum) { 3033 QualType ParamTypes[2]; 3034 3035 // T& operator=(T&, T) 3036 ParamTypes[0] = Context.getLValueReferenceType(*Enum); 3037 ParamTypes[1] = *Enum; 3038 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3039 /*IsAssignmentOperator=*/false); 3040 3041 if (!Context.getCanonicalType(*Enum).isVolatileQualified()) { 3042 // volatile T& operator=(volatile T&, T) 3043 ParamTypes[0] = Context.getLValueReferenceType((*Enum).withVolatile()); 3044 ParamTypes[1] = *Enum; 3045 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3046 /*IsAssignmentOperator=*/false); 3047 } 3048 } 3049 // Fall through. 3050 3051 case OO_PlusEqual: 3052 case OO_MinusEqual: 3053 // C++ [over.built]p19: 3054 // 3055 // For every pair (T, VQ), where T is any type and VQ is either 3056 // volatile or empty, there exist candidate operator functions 3057 // of the form 3058 // 3059 // T*VQ& operator=(T*VQ&, T*); 3060 // 3061 // C++ [over.built]p21: 3062 // 3063 // For every pair (T, VQ), where T is a cv-qualified or 3064 // cv-unqualified object type and VQ is either volatile or 3065 // empty, there exist candidate operator functions of the form 3066 // 3067 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 3068 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 3069 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3070 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3071 QualType ParamTypes[2]; 3072 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 3073 3074 // non-volatile version 3075 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 3076 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3077 /*IsAssigmentOperator=*/Op == OO_Equal); 3078 3079 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 3080 // volatile version 3081 ParamTypes[0] = Context.getLValueReferenceType((*Ptr).withVolatile()); 3082 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3083 /*IsAssigmentOperator=*/Op == OO_Equal); 3084 } 3085 } 3086 // Fall through. 3087 3088 case OO_StarEqual: 3089 case OO_SlashEqual: 3090 // C++ [over.built]p18: 3091 // 3092 // For every triple (L, VQ, R), where L is an arithmetic type, 3093 // VQ is either volatile or empty, and R is a promoted 3094 // arithmetic type, there exist candidate operator functions of 3095 // the form 3096 // 3097 // VQ L& operator=(VQ L&, R); 3098 // VQ L& operator*=(VQ L&, R); 3099 // VQ L& operator/=(VQ L&, R); 3100 // VQ L& operator+=(VQ L&, R); 3101 // VQ L& operator-=(VQ L&, R); 3102 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 3103 for (unsigned Right = FirstPromotedArithmeticType; 3104 Right < LastPromotedArithmeticType; ++Right) { 3105 QualType ParamTypes[2]; 3106 ParamTypes[1] = ArithmeticTypes[Right]; 3107 3108 // Add this built-in operator as a candidate (VQ is empty). 3109 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3110 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3111 /*IsAssigmentOperator=*/Op == OO_Equal); 3112 3113 // Add this built-in operator as a candidate (VQ is 'volatile'). 3114 ParamTypes[0] = ArithmeticTypes[Left].withVolatile(); 3115 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3116 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3117 /*IsAssigmentOperator=*/Op == OO_Equal); 3118 } 3119 } 3120 break; 3121 3122 case OO_PercentEqual: 3123 case OO_LessLessEqual: 3124 case OO_GreaterGreaterEqual: 3125 case OO_AmpEqual: 3126 case OO_CaretEqual: 3127 case OO_PipeEqual: 3128 // C++ [over.built]p22: 3129 // 3130 // For every triple (L, VQ, R), where L is an integral type, VQ 3131 // is either volatile or empty, and R is a promoted integral 3132 // type, there exist candidate operator functions of the form 3133 // 3134 // VQ L& operator%=(VQ L&, R); 3135 // VQ L& operator<<=(VQ L&, R); 3136 // VQ L& operator>>=(VQ L&, R); 3137 // VQ L& operator&=(VQ L&, R); 3138 // VQ L& operator^=(VQ L&, R); 3139 // VQ L& operator|=(VQ L&, R); 3140 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 3141 for (unsigned Right = FirstPromotedIntegralType; 3142 Right < LastPromotedIntegralType; ++Right) { 3143 QualType ParamTypes[2]; 3144 ParamTypes[1] = ArithmeticTypes[Right]; 3145 3146 // Add this built-in operator as a candidate (VQ is empty). 3147 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3148 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3149 3150 // Add this built-in operator as a candidate (VQ is 'volatile'). 3151 ParamTypes[0] = ArithmeticTypes[Left]; 3152 ParamTypes[0].addVolatile(); 3153 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3154 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3155 } 3156 } 3157 break; 3158 3159 case OO_Exclaim: { 3160 // C++ [over.operator]p23: 3161 // 3162 // There also exist candidate operator functions of the form 3163 // 3164 // bool operator!(bool); 3165 // bool operator&&(bool, bool); [BELOW] 3166 // bool operator||(bool, bool); [BELOW] 3167 QualType ParamTy = Context.BoolTy; 3168 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 3169 /*IsAssignmentOperator=*/false, 3170 /*NumContextualBoolArguments=*/1); 3171 break; 3172 } 3173 3174 case OO_AmpAmp: 3175 case OO_PipePipe: { 3176 // C++ [over.operator]p23: 3177 // 3178 // There also exist candidate operator functions of the form 3179 // 3180 // bool operator!(bool); [ABOVE] 3181 // bool operator&&(bool, bool); 3182 // bool operator||(bool, bool); 3183 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 3184 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 3185 /*IsAssignmentOperator=*/false, 3186 /*NumContextualBoolArguments=*/2); 3187 break; 3188 } 3189 3190 case OO_Subscript: 3191 // C++ [over.built]p13: 3192 // 3193 // For every cv-qualified or cv-unqualified object type T there 3194 // exist candidate operator functions of the form 3195 // 3196 // T* operator+(T*, ptrdiff_t); [ABOVE] 3197 // T& operator[](T*, ptrdiff_t); 3198 // T* operator-(T*, ptrdiff_t); [ABOVE] 3199 // T* operator+(ptrdiff_t, T*); [ABOVE] 3200 // T& operator[](ptrdiff_t, T*); 3201 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3202 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3203 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 3204 QualType PointeeType = (*Ptr)->getAsPointerType()->getPointeeType(); 3205 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 3206 3207 // T& operator[](T*, ptrdiff_t) 3208 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3209 3210 // T& operator[](ptrdiff_t, T*); 3211 ParamTypes[0] = ParamTypes[1]; 3212 ParamTypes[1] = *Ptr; 3213 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3214 } 3215 break; 3216 3217 case OO_ArrowStar: 3218 // FIXME: No support for pointer-to-members yet. 3219 break; 3220 } 3221} 3222 3223/// \brief Add function candidates found via argument-dependent lookup 3224/// to the set of overloading candidates. 3225/// 3226/// This routine performs argument-dependent name lookup based on the 3227/// given function name (which may also be an operator name) and adds 3228/// all of the overload candidates found by ADL to the overload 3229/// candidate set (C++ [basic.lookup.argdep]). 3230void 3231Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 3232 Expr **Args, unsigned NumArgs, 3233 OverloadCandidateSet& CandidateSet) { 3234 FunctionSet Functions; 3235 3236 // Record all of the function candidates that we've already 3237 // added to the overload set, so that we don't add those same 3238 // candidates a second time. 3239 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3240 CandEnd = CandidateSet.end(); 3241 Cand != CandEnd; ++Cand) 3242 if (Cand->Function) 3243 Functions.insert(Cand->Function); 3244 3245 ArgumentDependentLookup(Name, Args, NumArgs, Functions); 3246 3247 // Erase all of the candidates we already knew about. 3248 // FIXME: This is suboptimal. Is there a better way? 3249 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3250 CandEnd = CandidateSet.end(); 3251 Cand != CandEnd; ++Cand) 3252 if (Cand->Function) 3253 Functions.erase(Cand->Function); 3254 3255 // For each of the ADL candidates we found, add it to the overload 3256 // set. 3257 for (FunctionSet::iterator Func = Functions.begin(), 3258 FuncEnd = Functions.end(); 3259 Func != FuncEnd; ++Func) 3260 AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet); 3261} 3262 3263/// isBetterOverloadCandidate - Determines whether the first overload 3264/// candidate is a better candidate than the second (C++ 13.3.3p1). 3265bool 3266Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 3267 const OverloadCandidate& Cand2) 3268{ 3269 // Define viable functions to be better candidates than non-viable 3270 // functions. 3271 if (!Cand2.Viable) 3272 return Cand1.Viable; 3273 else if (!Cand1.Viable) 3274 return false; 3275 3276 // C++ [over.match.best]p1: 3277 // 3278 // -- if F is a static member function, ICS1(F) is defined such 3279 // that ICS1(F) is neither better nor worse than ICS1(G) for 3280 // any function G, and, symmetrically, ICS1(G) is neither 3281 // better nor worse than ICS1(F). 3282 unsigned StartArg = 0; 3283 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 3284 StartArg = 1; 3285 3286 // (C++ 13.3.3p1): a viable function F1 is defined to be a better 3287 // function than another viable function F2 if for all arguments i, 3288 // ICSi(F1) is not a worse conversion sequence than ICSi(F2), and 3289 // then... 3290 unsigned NumArgs = Cand1.Conversions.size(); 3291 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 3292 bool HasBetterConversion = false; 3293 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 3294 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 3295 Cand2.Conversions[ArgIdx])) { 3296 case ImplicitConversionSequence::Better: 3297 // Cand1 has a better conversion sequence. 3298 HasBetterConversion = true; 3299 break; 3300 3301 case ImplicitConversionSequence::Worse: 3302 // Cand1 can't be better than Cand2. 3303 return false; 3304 3305 case ImplicitConversionSequence::Indistinguishable: 3306 // Do nothing. 3307 break; 3308 } 3309 } 3310 3311 if (HasBetterConversion) 3312 return true; 3313 3314 // FIXME: Several other bullets in (C++ 13.3.3p1) need to be 3315 // implemented, but they require template support. 3316 3317 // C++ [over.match.best]p1b4: 3318 // 3319 // -- the context is an initialization by user-defined conversion 3320 // (see 8.5, 13.3.1.5) and the standard conversion sequence 3321 // from the return type of F1 to the destination type (i.e., 3322 // the type of the entity being initialized) is a better 3323 // conversion sequence than the standard conversion sequence 3324 // from the return type of F2 to the destination type. 3325 if (Cand1.Function && Cand2.Function && 3326 isa<CXXConversionDecl>(Cand1.Function) && 3327 isa<CXXConversionDecl>(Cand2.Function)) { 3328 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 3329 Cand2.FinalConversion)) { 3330 case ImplicitConversionSequence::Better: 3331 // Cand1 has a better conversion sequence. 3332 return true; 3333 3334 case ImplicitConversionSequence::Worse: 3335 // Cand1 can't be better than Cand2. 3336 return false; 3337 3338 case ImplicitConversionSequence::Indistinguishable: 3339 // Do nothing 3340 break; 3341 } 3342 } 3343 3344 return false; 3345} 3346 3347/// BestViableFunction - Computes the best viable function (C++ 13.3.3) 3348/// within an overload candidate set. If overloading is successful, 3349/// the result will be OR_Success and Best will be set to point to the 3350/// best viable function within the candidate set. Otherwise, one of 3351/// several kinds of errors will be returned; see 3352/// Sema::OverloadingResult. 3353Sema::OverloadingResult 3354Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 3355 OverloadCandidateSet::iterator& Best) 3356{ 3357 // Find the best viable function. 3358 Best = CandidateSet.end(); 3359 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3360 Cand != CandidateSet.end(); ++Cand) { 3361 if (Cand->Viable) { 3362 if (Best == CandidateSet.end() || isBetterOverloadCandidate(*Cand, *Best)) 3363 Best = Cand; 3364 } 3365 } 3366 3367 // If we didn't find any viable functions, abort. 3368 if (Best == CandidateSet.end()) 3369 return OR_No_Viable_Function; 3370 3371 // Make sure that this function is better than every other viable 3372 // function. If not, we have an ambiguity. 3373 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3374 Cand != CandidateSet.end(); ++Cand) { 3375 if (Cand->Viable && 3376 Cand != Best && 3377 !isBetterOverloadCandidate(*Best, *Cand)) { 3378 Best = CandidateSet.end(); 3379 return OR_Ambiguous; 3380 } 3381 } 3382 3383 // Best is the best viable function. 3384 if (Best->Function && 3385 (Best->Function->isDeleted() || 3386 Best->Function->getAttr<UnavailableAttr>())) 3387 return OR_Deleted; 3388 3389 // If Best refers to a function that is either deleted (C++0x) or 3390 // unavailable (Clang extension) report an error. 3391 3392 return OR_Success; 3393} 3394 3395/// PrintOverloadCandidates - When overload resolution fails, prints 3396/// diagnostic messages containing the candidates in the candidate 3397/// set. If OnlyViable is true, only viable candidates will be printed. 3398void 3399Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 3400 bool OnlyViable) 3401{ 3402 OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3403 LastCand = CandidateSet.end(); 3404 for (; Cand != LastCand; ++Cand) { 3405 if (Cand->Viable || !OnlyViable) { 3406 if (Cand->Function) { 3407 if (Cand->Function->isDeleted() || 3408 Cand->Function->getAttr<UnavailableAttr>()) { 3409 // Deleted or "unavailable" function. 3410 Diag(Cand->Function->getLocation(), diag::err_ovl_candidate_deleted) 3411 << Cand->Function->isDeleted(); 3412 } else { 3413 // Normal function 3414 // FIXME: Give a better reason! 3415 Diag(Cand->Function->getLocation(), diag::err_ovl_candidate); 3416 } 3417 } else if (Cand->IsSurrogate) { 3418 // Desugar the type of the surrogate down to a function type, 3419 // retaining as many typedefs as possible while still showing 3420 // the function type (and, therefore, its parameter types). 3421 QualType FnType = Cand->Surrogate->getConversionType(); 3422 bool isLValueReference = false; 3423 bool isRValueReference = false; 3424 bool isPointer = false; 3425 if (const LValueReferenceType *FnTypeRef = 3426 FnType->getAsLValueReferenceType()) { 3427 FnType = FnTypeRef->getPointeeType(); 3428 isLValueReference = true; 3429 } else if (const RValueReferenceType *FnTypeRef = 3430 FnType->getAsRValueReferenceType()) { 3431 FnType = FnTypeRef->getPointeeType(); 3432 isRValueReference = true; 3433 } 3434 if (const PointerType *FnTypePtr = FnType->getAsPointerType()) { 3435 FnType = FnTypePtr->getPointeeType(); 3436 isPointer = true; 3437 } 3438 // Desugar down to a function type. 3439 FnType = QualType(FnType->getAsFunctionType(), 0); 3440 // Reconstruct the pointer/reference as appropriate. 3441 if (isPointer) FnType = Context.getPointerType(FnType); 3442 if (isRValueReference) FnType = Context.getRValueReferenceType(FnType); 3443 if (isLValueReference) FnType = Context.getLValueReferenceType(FnType); 3444 3445 Diag(Cand->Surrogate->getLocation(), diag::err_ovl_surrogate_cand) 3446 << FnType; 3447 } else { 3448 // FIXME: We need to get the identifier in here 3449 // FIXME: Do we want the error message to point at the 3450 // operator? (built-ins won't have a location) 3451 QualType FnType 3452 = Context.getFunctionType(Cand->BuiltinTypes.ResultTy, 3453 Cand->BuiltinTypes.ParamTypes, 3454 Cand->Conversions.size(), 3455 false, 0); 3456 3457 Diag(SourceLocation(), diag::err_ovl_builtin_candidate) << FnType; 3458 } 3459 } 3460 } 3461} 3462 3463/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 3464/// an overloaded function (C++ [over.over]), where @p From is an 3465/// expression with overloaded function type and @p ToType is the type 3466/// we're trying to resolve to. For example: 3467/// 3468/// @code 3469/// int f(double); 3470/// int f(int); 3471/// 3472/// int (*pfd)(double) = f; // selects f(double) 3473/// @endcode 3474/// 3475/// This routine returns the resulting FunctionDecl if it could be 3476/// resolved, and NULL otherwise. When @p Complain is true, this 3477/// routine will emit diagnostics if there is an error. 3478FunctionDecl * 3479Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 3480 bool Complain) { 3481 QualType FunctionType = ToType; 3482 bool IsMember = false; 3483 if (const PointerType *ToTypePtr = ToType->getAsPointerType()) 3484 FunctionType = ToTypePtr->getPointeeType(); 3485 else if (const ReferenceType *ToTypeRef = ToType->getAsReferenceType()) 3486 FunctionType = ToTypeRef->getPointeeType(); 3487 else if (const MemberPointerType *MemTypePtr = 3488 ToType->getAsMemberPointerType()) { 3489 FunctionType = MemTypePtr->getPointeeType(); 3490 IsMember = true; 3491 } 3492 3493 // We only look at pointers or references to functions. 3494 if (!FunctionType->isFunctionType()) 3495 return 0; 3496 3497 // Find the actual overloaded function declaration. 3498 OverloadedFunctionDecl *Ovl = 0; 3499 3500 // C++ [over.over]p1: 3501 // [...] [Note: any redundant set of parentheses surrounding the 3502 // overloaded function name is ignored (5.1). ] 3503 Expr *OvlExpr = From->IgnoreParens(); 3504 3505 // C++ [over.over]p1: 3506 // [...] The overloaded function name can be preceded by the & 3507 // operator. 3508 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(OvlExpr)) { 3509 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 3510 OvlExpr = UnOp->getSubExpr()->IgnoreParens(); 3511 } 3512 3513 // Try to dig out the overloaded function. 3514 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(OvlExpr)) 3515 Ovl = dyn_cast<OverloadedFunctionDecl>(DR->getDecl()); 3516 3517 // If there's no overloaded function declaration, we're done. 3518 if (!Ovl) 3519 return 0; 3520 3521 // Look through all of the overloaded functions, searching for one 3522 // whose type matches exactly. 3523 // FIXME: When templates or using declarations come along, we'll actually 3524 // have to deal with duplicates, partial ordering, etc. For now, we 3525 // can just do a simple search. 3526 FunctionType = Context.getCanonicalType(FunctionType.getUnqualifiedType()); 3527 for (OverloadedFunctionDecl::function_iterator Fun = Ovl->function_begin(); 3528 Fun != Ovl->function_end(); ++Fun) { 3529 // C++ [over.over]p3: 3530 // Non-member functions and static member functions match 3531 // targets of type "pointer-to-function" or "reference-to-function." 3532 // Nonstatic member functions match targets of 3533 // type "pointer-to-member-function." 3534 // Note that according to DR 247, the containing class does not matter. 3535 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(*Fun)) { 3536 // Skip non-static functions when converting to pointer, and static 3537 // when converting to member pointer. 3538 if (Method->isStatic() == IsMember) 3539 continue; 3540 } else if (IsMember) 3541 continue; 3542 3543 if (FunctionType == Context.getCanonicalType((*Fun)->getType())) 3544 return *Fun; 3545 } 3546 3547 return 0; 3548} 3549 3550/// ResolveOverloadedCallFn - Given the call expression that calls Fn 3551/// (which eventually refers to the declaration Func) and the call 3552/// arguments Args/NumArgs, attempt to resolve the function call down 3553/// to a specific function. If overload resolution succeeds, returns 3554/// the function declaration produced by overload 3555/// resolution. Otherwise, emits diagnostics, deletes all of the 3556/// arguments and Fn, and returns NULL. 3557FunctionDecl *Sema::ResolveOverloadedCallFn(Expr *Fn, NamedDecl *Callee, 3558 DeclarationName UnqualifiedName, 3559 SourceLocation LParenLoc, 3560 Expr **Args, unsigned NumArgs, 3561 SourceLocation *CommaLocs, 3562 SourceLocation RParenLoc, 3563 bool &ArgumentDependentLookup) { 3564 OverloadCandidateSet CandidateSet; 3565 3566 // Add the functions denoted by Callee to the set of candidate 3567 // functions. While we're doing so, track whether argument-dependent 3568 // lookup still applies, per: 3569 // 3570 // C++0x [basic.lookup.argdep]p3: 3571 // Let X be the lookup set produced by unqualified lookup (3.4.1) 3572 // and let Y be the lookup set produced by argument dependent 3573 // lookup (defined as follows). If X contains 3574 // 3575 // -- a declaration of a class member, or 3576 // 3577 // -- a block-scope function declaration that is not a 3578 // using-declaration, or 3579 // 3580 // -- a declaration that is neither a function or a function 3581 // template 3582 // 3583 // then Y is empty. 3584 if (OverloadedFunctionDecl *Ovl 3585 = dyn_cast_or_null<OverloadedFunctionDecl>(Callee)) { 3586 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 3587 FuncEnd = Ovl->function_end(); 3588 Func != FuncEnd; ++Func) { 3589 AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet); 3590 3591 if ((*Func)->getDeclContext()->isRecord() || 3592 (*Func)->getDeclContext()->isFunctionOrMethod()) 3593 ArgumentDependentLookup = false; 3594 } 3595 } else if (FunctionDecl *Func = dyn_cast_or_null<FunctionDecl>(Callee)) { 3596 AddOverloadCandidate(Func, Args, NumArgs, CandidateSet); 3597 3598 if (Func->getDeclContext()->isRecord() || 3599 Func->getDeclContext()->isFunctionOrMethod()) 3600 ArgumentDependentLookup = false; 3601 } 3602 3603 if (Callee) 3604 UnqualifiedName = Callee->getDeclName(); 3605 3606 if (ArgumentDependentLookup) 3607 AddArgumentDependentLookupCandidates(UnqualifiedName, Args, NumArgs, 3608 CandidateSet); 3609 3610 OverloadCandidateSet::iterator Best; 3611 switch (BestViableFunction(CandidateSet, Best)) { 3612 case OR_Success: 3613 return Best->Function; 3614 3615 case OR_No_Viable_Function: 3616 Diag(Fn->getSourceRange().getBegin(), 3617 diag::err_ovl_no_viable_function_in_call) 3618 << UnqualifiedName << Fn->getSourceRange(); 3619 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3620 break; 3621 3622 case OR_Ambiguous: 3623 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 3624 << UnqualifiedName << Fn->getSourceRange(); 3625 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3626 break; 3627 3628 case OR_Deleted: 3629 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 3630 << Best->Function->isDeleted() 3631 << UnqualifiedName 3632 << Fn->getSourceRange(); 3633 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3634 break; 3635 } 3636 3637 // Overload resolution failed. Destroy all of the subexpressions and 3638 // return NULL. 3639 Fn->Destroy(Context); 3640 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 3641 Args[Arg]->Destroy(Context); 3642 return 0; 3643} 3644 3645/// \brief Create a unary operation that may resolve to an overloaded 3646/// operator. 3647/// 3648/// \param OpLoc The location of the operator itself (e.g., '*'). 3649/// 3650/// \param OpcIn The UnaryOperator::Opcode that describes this 3651/// operator. 3652/// 3653/// \param Functions The set of non-member functions that will be 3654/// considered by overload resolution. The caller needs to build this 3655/// set based on the context using, e.g., 3656/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 3657/// set should not contain any member functions; those will be added 3658/// by CreateOverloadedUnaryOp(). 3659/// 3660/// \param input The input argument. 3661Sema::OwningExprResult Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, 3662 unsigned OpcIn, 3663 FunctionSet &Functions, 3664 ExprArg input) { 3665 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 3666 Expr *Input = (Expr *)input.get(); 3667 3668 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 3669 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 3670 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3671 3672 Expr *Args[2] = { Input, 0 }; 3673 unsigned NumArgs = 1; 3674 3675 // For post-increment and post-decrement, add the implicit '0' as 3676 // the second argument, so that we know this is a post-increment or 3677 // post-decrement. 3678 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 3679 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 3680 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 3681 SourceLocation()); 3682 NumArgs = 2; 3683 } 3684 3685 if (Input->isTypeDependent()) { 3686 OverloadedFunctionDecl *Overloads 3687 = OverloadedFunctionDecl::Create(Context, CurContext, OpName); 3688 for (FunctionSet::iterator Func = Functions.begin(), 3689 FuncEnd = Functions.end(); 3690 Func != FuncEnd; ++Func) 3691 Overloads->addOverload(*Func); 3692 3693 DeclRefExpr *Fn = new (Context) DeclRefExpr(Overloads, Context.OverloadTy, 3694 OpLoc, false, false); 3695 3696 input.release(); 3697 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 3698 &Args[0], NumArgs, 3699 Context.DependentTy, 3700 OpLoc)); 3701 } 3702 3703 // Build an empty overload set. 3704 OverloadCandidateSet CandidateSet; 3705 3706 // Add the candidates from the given function set. 3707 AddFunctionCandidates(Functions, &Args[0], NumArgs, CandidateSet, false); 3708 3709 // Add operator candidates that are member functions. 3710 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 3711 3712 // Add builtin operator candidates. 3713 AddBuiltinOperatorCandidates(Op, &Args[0], NumArgs, CandidateSet); 3714 3715 // Perform overload resolution. 3716 OverloadCandidateSet::iterator Best; 3717 switch (BestViableFunction(CandidateSet, Best)) { 3718 case OR_Success: { 3719 // We found a built-in operator or an overloaded operator. 3720 FunctionDecl *FnDecl = Best->Function; 3721 3722 if (FnDecl) { 3723 // We matched an overloaded operator. Build a call to that 3724 // operator. 3725 3726 // Convert the arguments. 3727 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 3728 if (PerformObjectArgumentInitialization(Input, Method)) 3729 return ExprError(); 3730 } else { 3731 // Convert the arguments. 3732 if (PerformCopyInitialization(Input, 3733 FnDecl->getParamDecl(0)->getType(), 3734 "passing")) 3735 return ExprError(); 3736 } 3737 3738 // Determine the result type 3739 QualType ResultTy 3740 = FnDecl->getType()->getAsFunctionType()->getResultType(); 3741 ResultTy = ResultTy.getNonReferenceType(); 3742 3743 // Build the actual expression node. 3744 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 3745 SourceLocation()); 3746 UsualUnaryConversions(FnExpr); 3747 3748 input.release(); 3749 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 3750 &Input, 1, ResultTy, 3751 OpLoc)); 3752 } else { 3753 // We matched a built-in operator. Convert the arguments, then 3754 // break out so that we will build the appropriate built-in 3755 // operator node. 3756 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 3757 Best->Conversions[0], "passing")) 3758 return ExprError(); 3759 3760 break; 3761 } 3762 } 3763 3764 case OR_No_Viable_Function: 3765 // No viable function; fall through to handling this as a 3766 // built-in operator, which will produce an error message for us. 3767 break; 3768 3769 case OR_Ambiguous: 3770 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 3771 << UnaryOperator::getOpcodeStr(Opc) 3772 << Input->getSourceRange(); 3773 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3774 return ExprError(); 3775 3776 case OR_Deleted: 3777 Diag(OpLoc, diag::err_ovl_deleted_oper) 3778 << Best->Function->isDeleted() 3779 << UnaryOperator::getOpcodeStr(Opc) 3780 << Input->getSourceRange(); 3781 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3782 return ExprError(); 3783 } 3784 3785 // Either we found no viable overloaded operator or we matched a 3786 // built-in operator. In either case, fall through to trying to 3787 // build a built-in operation. 3788 input.release(); 3789 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 3790} 3791 3792/// \brief Create a binary operation that may resolve to an overloaded 3793/// operator. 3794/// 3795/// \param OpLoc The location of the operator itself (e.g., '+'). 3796/// 3797/// \param OpcIn The BinaryOperator::Opcode that describes this 3798/// operator. 3799/// 3800/// \param Functions The set of non-member functions that will be 3801/// considered by overload resolution. The caller needs to build this 3802/// set based on the context using, e.g., 3803/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 3804/// set should not contain any member functions; those will be added 3805/// by CreateOverloadedBinOp(). 3806/// 3807/// \param LHS Left-hand argument. 3808/// \param RHS Right-hand argument. 3809Sema::OwningExprResult 3810Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 3811 unsigned OpcIn, 3812 FunctionSet &Functions, 3813 Expr *LHS, Expr *RHS) { 3814 Expr *Args[2] = { LHS, RHS }; 3815 3816 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 3817 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 3818 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3819 3820 // If either side is type-dependent, create an appropriate dependent 3821 // expression. 3822 if (LHS->isTypeDependent() || RHS->isTypeDependent()) { 3823 // .* cannot be overloaded. 3824 if (Opc == BinaryOperator::PtrMemD) 3825 return Owned(new (Context) BinaryOperator(LHS, RHS, Opc, 3826 Context.DependentTy, OpLoc)); 3827 3828 OverloadedFunctionDecl *Overloads 3829 = OverloadedFunctionDecl::Create(Context, CurContext, OpName); 3830 for (FunctionSet::iterator Func = Functions.begin(), 3831 FuncEnd = Functions.end(); 3832 Func != FuncEnd; ++Func) 3833 Overloads->addOverload(*Func); 3834 3835 DeclRefExpr *Fn = new (Context) DeclRefExpr(Overloads, Context.OverloadTy, 3836 OpLoc, false, false); 3837 3838 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 3839 Args, 2, 3840 Context.DependentTy, 3841 OpLoc)); 3842 } 3843 3844 // If this is the .* operator, which is not overloadable, just 3845 // create a built-in binary operator. 3846 if (Opc == BinaryOperator::PtrMemD) 3847 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3848 3849 // If this is one of the assignment operators, we only perform 3850 // overload resolution if the left-hand side is a class or 3851 // enumeration type (C++ [expr.ass]p3). 3852 if (Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign && 3853 !LHS->getType()->isOverloadableType()) 3854 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3855 3856 // Build an empty overload set. 3857 OverloadCandidateSet CandidateSet; 3858 3859 // Add the candidates from the given function set. 3860 AddFunctionCandidates(Functions, Args, 2, CandidateSet, false); 3861 3862 // Add operator candidates that are member functions. 3863 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 3864 3865 // Add builtin operator candidates. 3866 AddBuiltinOperatorCandidates(Op, Args, 2, CandidateSet); 3867 3868 // Perform overload resolution. 3869 OverloadCandidateSet::iterator Best; 3870 switch (BestViableFunction(CandidateSet, Best)) { 3871 case OR_Success: { 3872 // We found a built-in operator or an overloaded operator. 3873 FunctionDecl *FnDecl = Best->Function; 3874 3875 if (FnDecl) { 3876 // We matched an overloaded operator. Build a call to that 3877 // operator. 3878 3879 // Convert the arguments. 3880 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 3881 if (PerformObjectArgumentInitialization(LHS, Method) || 3882 PerformCopyInitialization(RHS, FnDecl->getParamDecl(0)->getType(), 3883 "passing")) 3884 return ExprError(); 3885 } else { 3886 // Convert the arguments. 3887 if (PerformCopyInitialization(LHS, FnDecl->getParamDecl(0)->getType(), 3888 "passing") || 3889 PerformCopyInitialization(RHS, FnDecl->getParamDecl(1)->getType(), 3890 "passing")) 3891 return ExprError(); 3892 } 3893 3894 // Determine the result type 3895 QualType ResultTy 3896 = FnDecl->getType()->getAsFunctionType()->getResultType(); 3897 ResultTy = ResultTy.getNonReferenceType(); 3898 3899 // Build the actual expression node. 3900 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 3901 SourceLocation()); 3902 UsualUnaryConversions(FnExpr); 3903 3904 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 3905 Args, 2, ResultTy, 3906 OpLoc)); 3907 } else { 3908 // We matched a built-in operator. Convert the arguments, then 3909 // break out so that we will build the appropriate built-in 3910 // operator node. 3911 if (PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0], 3912 Best->Conversions[0], "passing") || 3913 PerformImplicitConversion(RHS, Best->BuiltinTypes.ParamTypes[1], 3914 Best->Conversions[1], "passing")) 3915 return ExprError(); 3916 3917 break; 3918 } 3919 } 3920 3921 case OR_No_Viable_Function: 3922 // No viable function; fall through to handling this as a 3923 // built-in operator, which will produce an error message for us. 3924 break; 3925 3926 case OR_Ambiguous: 3927 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 3928 << BinaryOperator::getOpcodeStr(Opc) 3929 << LHS->getSourceRange() << RHS->getSourceRange(); 3930 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3931 return ExprError(); 3932 3933 case OR_Deleted: 3934 Diag(OpLoc, diag::err_ovl_deleted_oper) 3935 << Best->Function->isDeleted() 3936 << BinaryOperator::getOpcodeStr(Opc) 3937 << LHS->getSourceRange() << RHS->getSourceRange(); 3938 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3939 return ExprError(); 3940 } 3941 3942 // Either we found no viable overloaded operator or we matched a 3943 // built-in operator. In either case, try to build a built-in 3944 // operation. 3945 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3946} 3947 3948/// BuildCallToMemberFunction - Build a call to a member 3949/// function. MemExpr is the expression that refers to the member 3950/// function (and includes the object parameter), Args/NumArgs are the 3951/// arguments to the function call (not including the object 3952/// parameter). The caller needs to validate that the member 3953/// expression refers to a member function or an overloaded member 3954/// function. 3955Sema::ExprResult 3956Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 3957 SourceLocation LParenLoc, Expr **Args, 3958 unsigned NumArgs, SourceLocation *CommaLocs, 3959 SourceLocation RParenLoc) { 3960 // Dig out the member expression. This holds both the object 3961 // argument and the member function we're referring to. 3962 MemberExpr *MemExpr = 0; 3963 if (ParenExpr *ParenE = dyn_cast<ParenExpr>(MemExprE)) 3964 MemExpr = dyn_cast<MemberExpr>(ParenE->getSubExpr()); 3965 else 3966 MemExpr = dyn_cast<MemberExpr>(MemExprE); 3967 assert(MemExpr && "Building member call without member expression"); 3968 3969 // Extract the object argument. 3970 Expr *ObjectArg = MemExpr->getBase(); 3971 if (MemExpr->isArrow()) 3972 ObjectArg = new (Context) UnaryOperator(ObjectArg, UnaryOperator::Deref, 3973 ObjectArg->getType()->getAsPointerType()->getPointeeType(), 3974 ObjectArg->getLocStart()); 3975 CXXMethodDecl *Method = 0; 3976 if (OverloadedFunctionDecl *Ovl 3977 = dyn_cast<OverloadedFunctionDecl>(MemExpr->getMemberDecl())) { 3978 // Add overload candidates 3979 OverloadCandidateSet CandidateSet; 3980 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 3981 FuncEnd = Ovl->function_end(); 3982 Func != FuncEnd; ++Func) { 3983 assert(isa<CXXMethodDecl>(*Func) && "Function is not a method"); 3984 Method = cast<CXXMethodDecl>(*Func); 3985 AddMethodCandidate(Method, ObjectArg, Args, NumArgs, CandidateSet, 3986 /*SuppressUserConversions=*/false); 3987 } 3988 3989 OverloadCandidateSet::iterator Best; 3990 switch (BestViableFunction(CandidateSet, Best)) { 3991 case OR_Success: 3992 Method = cast<CXXMethodDecl>(Best->Function); 3993 break; 3994 3995 case OR_No_Viable_Function: 3996 Diag(MemExpr->getSourceRange().getBegin(), 3997 diag::err_ovl_no_viable_member_function_in_call) 3998 << Ovl->getDeclName() << MemExprE->getSourceRange(); 3999 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4000 // FIXME: Leaking incoming expressions! 4001 return true; 4002 4003 case OR_Ambiguous: 4004 Diag(MemExpr->getSourceRange().getBegin(), 4005 diag::err_ovl_ambiguous_member_call) 4006 << Ovl->getDeclName() << MemExprE->getSourceRange(); 4007 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4008 // FIXME: Leaking incoming expressions! 4009 return true; 4010 4011 case OR_Deleted: 4012 Diag(MemExpr->getSourceRange().getBegin(), 4013 diag::err_ovl_deleted_member_call) 4014 << Best->Function->isDeleted() 4015 << Ovl->getDeclName() << MemExprE->getSourceRange(); 4016 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4017 // FIXME: Leaking incoming expressions! 4018 return true; 4019 } 4020 4021 FixOverloadedFunctionReference(MemExpr, Method); 4022 } else { 4023 Method = dyn_cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 4024 } 4025 4026 assert(Method && "Member call to something that isn't a method?"); 4027 ExprOwningPtr<CXXMemberCallExpr> 4028 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExpr, Args, 4029 NumArgs, 4030 Method->getResultType().getNonReferenceType(), 4031 RParenLoc)); 4032 4033 // Convert the object argument (for a non-static member function call). 4034 if (!Method->isStatic() && 4035 PerformObjectArgumentInitialization(ObjectArg, Method)) 4036 return true; 4037 MemExpr->setBase(ObjectArg); 4038 4039 // Convert the rest of the arguments 4040 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 4041 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 4042 RParenLoc)) 4043 return true; 4044 4045 return CheckFunctionCall(Method, TheCall.take()).release(); 4046} 4047 4048/// BuildCallToObjectOfClassType - Build a call to an object of class 4049/// type (C++ [over.call.object]), which can end up invoking an 4050/// overloaded function call operator (@c operator()) or performing a 4051/// user-defined conversion on the object argument. 4052Sema::ExprResult 4053Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 4054 SourceLocation LParenLoc, 4055 Expr **Args, unsigned NumArgs, 4056 SourceLocation *CommaLocs, 4057 SourceLocation RParenLoc) { 4058 assert(Object->getType()->isRecordType() && "Requires object type argument"); 4059 const RecordType *Record = Object->getType()->getAsRecordType(); 4060 4061 // C++ [over.call.object]p1: 4062 // If the primary-expression E in the function call syntax 4063 // evaluates to a class object of type “cv T”, then the set of 4064 // candidate functions includes at least the function call 4065 // operators of T. The function call operators of T are obtained by 4066 // ordinary lookup of the name operator() in the context of 4067 // (E).operator(). 4068 OverloadCandidateSet CandidateSet; 4069 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 4070 DeclContext::lookup_const_iterator Oper, OperEnd; 4071 for (llvm::tie(Oper, OperEnd) = Record->getDecl()->lookup(OpName); 4072 Oper != OperEnd; ++Oper) 4073 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Object, Args, NumArgs, 4074 CandidateSet, /*SuppressUserConversions=*/false); 4075 4076 // C++ [over.call.object]p2: 4077 // In addition, for each conversion function declared in T of the 4078 // form 4079 // 4080 // operator conversion-type-id () cv-qualifier; 4081 // 4082 // where cv-qualifier is the same cv-qualification as, or a 4083 // greater cv-qualification than, cv, and where conversion-type-id 4084 // denotes the type "pointer to function of (P1,...,Pn) returning 4085 // R", or the type "reference to pointer to function of 4086 // (P1,...,Pn) returning R", or the type "reference to function 4087 // of (P1,...,Pn) returning R", a surrogate call function [...] 4088 // is also considered as a candidate function. Similarly, 4089 // surrogate call functions are added to the set of candidate 4090 // functions for each conversion function declared in an 4091 // accessible base class provided the function is not hidden 4092 // within T by another intervening declaration. 4093 // 4094 // FIXME: Look in base classes for more conversion operators! 4095 OverloadedFunctionDecl *Conversions 4096 = cast<CXXRecordDecl>(Record->getDecl())->getConversionFunctions(); 4097 for (OverloadedFunctionDecl::function_iterator 4098 Func = Conversions->function_begin(), 4099 FuncEnd = Conversions->function_end(); 4100 Func != FuncEnd; ++Func) { 4101 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 4102 4103 // Strip the reference type (if any) and then the pointer type (if 4104 // any) to get down to what might be a function type. 4105 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 4106 if (const PointerType *ConvPtrType = ConvType->getAsPointerType()) 4107 ConvType = ConvPtrType->getPointeeType(); 4108 4109 if (const FunctionProtoType *Proto = ConvType->getAsFunctionProtoType()) 4110 AddSurrogateCandidate(Conv, Proto, Object, Args, NumArgs, CandidateSet); 4111 } 4112 4113 // Perform overload resolution. 4114 OverloadCandidateSet::iterator Best; 4115 switch (BestViableFunction(CandidateSet, Best)) { 4116 case OR_Success: 4117 // Overload resolution succeeded; we'll build the appropriate call 4118 // below. 4119 break; 4120 4121 case OR_No_Viable_Function: 4122 Diag(Object->getSourceRange().getBegin(), 4123 diag::err_ovl_no_viable_object_call) 4124 << Object->getType() << Object->getSourceRange(); 4125 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4126 break; 4127 4128 case OR_Ambiguous: 4129 Diag(Object->getSourceRange().getBegin(), 4130 diag::err_ovl_ambiguous_object_call) 4131 << Object->getType() << Object->getSourceRange(); 4132 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4133 break; 4134 4135 case OR_Deleted: 4136 Diag(Object->getSourceRange().getBegin(), 4137 diag::err_ovl_deleted_object_call) 4138 << Best->Function->isDeleted() 4139 << Object->getType() << Object->getSourceRange(); 4140 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4141 break; 4142 } 4143 4144 if (Best == CandidateSet.end()) { 4145 // We had an error; delete all of the subexpressions and return 4146 // the error. 4147 Object->Destroy(Context); 4148 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4149 Args[ArgIdx]->Destroy(Context); 4150 return true; 4151 } 4152 4153 if (Best->Function == 0) { 4154 // Since there is no function declaration, this is one of the 4155 // surrogate candidates. Dig out the conversion function. 4156 CXXConversionDecl *Conv 4157 = cast<CXXConversionDecl>( 4158 Best->Conversions[0].UserDefined.ConversionFunction); 4159 4160 // We selected one of the surrogate functions that converts the 4161 // object parameter to a function pointer. Perform the conversion 4162 // on the object argument, then let ActOnCallExpr finish the job. 4163 // FIXME: Represent the user-defined conversion in the AST! 4164 ImpCastExprToType(Object, 4165 Conv->getConversionType().getNonReferenceType(), 4166 Conv->getConversionType()->isLValueReferenceType()); 4167 return ActOnCallExpr(S, ExprArg(*this, Object), LParenLoc, 4168 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 4169 CommaLocs, RParenLoc).release(); 4170 } 4171 4172 // We found an overloaded operator(). Build a CXXOperatorCallExpr 4173 // that calls this method, using Object for the implicit object 4174 // parameter and passing along the remaining arguments. 4175 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 4176 const FunctionProtoType *Proto = Method->getType()->getAsFunctionProtoType(); 4177 4178 unsigned NumArgsInProto = Proto->getNumArgs(); 4179 unsigned NumArgsToCheck = NumArgs; 4180 4181 // Build the full argument list for the method call (the 4182 // implicit object parameter is placed at the beginning of the 4183 // list). 4184 Expr **MethodArgs; 4185 if (NumArgs < NumArgsInProto) { 4186 NumArgsToCheck = NumArgsInProto; 4187 MethodArgs = new Expr*[NumArgsInProto + 1]; 4188 } else { 4189 MethodArgs = new Expr*[NumArgs + 1]; 4190 } 4191 MethodArgs[0] = Object; 4192 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4193 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 4194 4195 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 4196 SourceLocation()); 4197 UsualUnaryConversions(NewFn); 4198 4199 // Once we've built TheCall, all of the expressions are properly 4200 // owned. 4201 QualType ResultTy = Method->getResultType().getNonReferenceType(); 4202 ExprOwningPtr<CXXOperatorCallExpr> 4203 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 4204 MethodArgs, NumArgs + 1, 4205 ResultTy, RParenLoc)); 4206 delete [] MethodArgs; 4207 4208 // We may have default arguments. If so, we need to allocate more 4209 // slots in the call for them. 4210 if (NumArgs < NumArgsInProto) 4211 TheCall->setNumArgs(Context, NumArgsInProto + 1); 4212 else if (NumArgs > NumArgsInProto) 4213 NumArgsToCheck = NumArgsInProto; 4214 4215 // Initialize the implicit object parameter. 4216 if (PerformObjectArgumentInitialization(Object, Method)) 4217 return true; 4218 TheCall->setArg(0, Object); 4219 4220 // Check the argument types. 4221 for (unsigned i = 0; i != NumArgsToCheck; i++) { 4222 Expr *Arg; 4223 if (i < NumArgs) { 4224 Arg = Args[i]; 4225 4226 // Pass the argument. 4227 QualType ProtoArgType = Proto->getArgType(i); 4228 if (PerformCopyInitialization(Arg, ProtoArgType, "passing")) 4229 return true; 4230 } else { 4231 Arg = new (Context) CXXDefaultArgExpr(Method->getParamDecl(i)); 4232 } 4233 4234 TheCall->setArg(i + 1, Arg); 4235 } 4236 4237 // If this is a variadic call, handle args passed through "...". 4238 if (Proto->isVariadic()) { 4239 // Promote the arguments (C99 6.5.2.2p7). 4240 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 4241 Expr *Arg = Args[i]; 4242 4243 DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 4244 TheCall->setArg(i + 1, Arg); 4245 } 4246 } 4247 4248 return CheckFunctionCall(Method, TheCall.take()).release(); 4249} 4250 4251/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 4252/// (if one exists), where @c Base is an expression of class type and 4253/// @c Member is the name of the member we're trying to find. 4254Action::ExprResult 4255Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc, 4256 SourceLocation MemberLoc, 4257 IdentifierInfo &Member) { 4258 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 4259 4260 // C++ [over.ref]p1: 4261 // 4262 // [...] An expression x->m is interpreted as (x.operator->())->m 4263 // for a class object x of type T if T::operator->() exists and if 4264 // the operator is selected as the best match function by the 4265 // overload resolution mechanism (13.3). 4266 // FIXME: look in base classes. 4267 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 4268 OverloadCandidateSet CandidateSet; 4269 const RecordType *BaseRecord = Base->getType()->getAsRecordType(); 4270 4271 DeclContext::lookup_const_iterator Oper, OperEnd; 4272 for (llvm::tie(Oper, OperEnd) = BaseRecord->getDecl()->lookup(OpName); 4273 Oper != OperEnd; ++Oper) 4274 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Base, 0, 0, CandidateSet, 4275 /*SuppressUserConversions=*/false); 4276 4277 ExprOwningPtr<Expr> BasePtr(this, Base); 4278 4279 // Perform overload resolution. 4280 OverloadCandidateSet::iterator Best; 4281 switch (BestViableFunction(CandidateSet, Best)) { 4282 case OR_Success: 4283 // Overload resolution succeeded; we'll build the call below. 4284 break; 4285 4286 case OR_No_Viable_Function: 4287 if (CandidateSet.empty()) 4288 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 4289 << BasePtr->getType() << BasePtr->getSourceRange(); 4290 else 4291 Diag(OpLoc, diag::err_ovl_no_viable_oper) 4292 << "operator->" << BasePtr->getSourceRange(); 4293 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4294 return true; 4295 4296 case OR_Ambiguous: 4297 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 4298 << "operator->" << BasePtr->getSourceRange(); 4299 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4300 return true; 4301 4302 case OR_Deleted: 4303 Diag(OpLoc, diag::err_ovl_deleted_oper) 4304 << Best->Function->isDeleted() 4305 << "operator->" << BasePtr->getSourceRange(); 4306 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4307 return true; 4308 } 4309 4310 // Convert the object parameter. 4311 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 4312 if (PerformObjectArgumentInitialization(Base, Method)) 4313 return true; 4314 4315 // No concerns about early exits now. 4316 BasePtr.take(); 4317 4318 // Build the operator call. 4319 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 4320 SourceLocation()); 4321 UsualUnaryConversions(FnExpr); 4322 Base = new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, &Base, 1, 4323 Method->getResultType().getNonReferenceType(), 4324 OpLoc); 4325 return ActOnMemberReferenceExpr(S, ExprArg(*this, Base), OpLoc, tok::arrow, 4326 MemberLoc, Member).release(); 4327} 4328 4329/// FixOverloadedFunctionReference - E is an expression that refers to 4330/// a C++ overloaded function (possibly with some parentheses and 4331/// perhaps a '&' around it). We have resolved the overloaded function 4332/// to the function declaration Fn, so patch up the expression E to 4333/// refer (possibly indirectly) to Fn. 4334void Sema::FixOverloadedFunctionReference(Expr *E, FunctionDecl *Fn) { 4335 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 4336 FixOverloadedFunctionReference(PE->getSubExpr(), Fn); 4337 E->setType(PE->getSubExpr()->getType()); 4338 } else if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 4339 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 4340 "Can only take the address of an overloaded function"); 4341 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 4342 if (Method->isStatic()) { 4343 // Do nothing: static member functions aren't any different 4344 // from non-member functions. 4345 } 4346 else if (QualifiedDeclRefExpr *DRE 4347 = dyn_cast<QualifiedDeclRefExpr>(UnOp->getSubExpr())) { 4348 // We have taken the address of a pointer to member 4349 // function. Perform the computation here so that we get the 4350 // appropriate pointer to member type. 4351 DRE->setDecl(Fn); 4352 DRE->setType(Fn->getType()); 4353 QualType ClassType 4354 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 4355 E->setType(Context.getMemberPointerType(Fn->getType(), 4356 ClassType.getTypePtr())); 4357 return; 4358 } 4359 } 4360 FixOverloadedFunctionReference(UnOp->getSubExpr(), Fn); 4361 E->setType(Context.getPointerType(UnOp->getSubExpr()->getType())); 4362 } else if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E)) { 4363 assert(isa<OverloadedFunctionDecl>(DR->getDecl()) && 4364 "Expected overloaded function"); 4365 DR->setDecl(Fn); 4366 E->setType(Fn->getType()); 4367 } else if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(E)) { 4368 MemExpr->setMemberDecl(Fn); 4369 E->setType(Fn->getType()); 4370 } else { 4371 assert(false && "Invalid reference to overloaded function"); 4372 } 4373} 4374 4375} // end namespace clang 4376