SemaOverload.cpp revision 6ab3524f72a6e64aa04973fa9433b5559abb3525
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 RRefBinding = false; 120 CopyConstructor = 0; 121} 122 123/// getRank - Retrieve the rank of this standard conversion sequence 124/// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the 125/// implicit conversions. 126ImplicitConversionRank StandardConversionSequence::getRank() const { 127 ImplicitConversionRank Rank = ICR_Exact_Match; 128 if (GetConversionRank(First) > Rank) 129 Rank = GetConversionRank(First); 130 if (GetConversionRank(Second) > Rank) 131 Rank = GetConversionRank(Second); 132 if (GetConversionRank(Third) > Rank) 133 Rank = GetConversionRank(Third); 134 return Rank; 135} 136 137/// isPointerConversionToBool - Determines whether this conversion is 138/// a conversion of a pointer or pointer-to-member to bool. This is 139/// used as part of the ranking of standard conversion sequences 140/// (C++ 13.3.3.2p4). 141bool StandardConversionSequence::isPointerConversionToBool() const 142{ 143 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 144 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 145 146 // Note that FromType has not necessarily been transformed by the 147 // array-to-pointer or function-to-pointer implicit conversions, so 148 // check for their presence as well as checking whether FromType is 149 // a pointer. 150 if (ToType->isBooleanType() && 151 (FromType->isPointerType() || FromType->isBlockPointerType() || 152 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer)) 153 return true; 154 155 return false; 156} 157 158/// isPointerConversionToVoidPointer - Determines whether this 159/// conversion is a conversion of a pointer to a void pointer. This is 160/// used as part of the ranking of standard conversion sequences (C++ 161/// 13.3.3.2p4). 162bool 163StandardConversionSequence:: 164isPointerConversionToVoidPointer(ASTContext& Context) const 165{ 166 QualType FromType = QualType::getFromOpaquePtr(FromTypePtr); 167 QualType ToType = QualType::getFromOpaquePtr(ToTypePtr); 168 169 // Note that FromType has not necessarily been transformed by the 170 // array-to-pointer implicit conversion, so check for its presence 171 // and redo the conversion to get a pointer. 172 if (First == ICK_Array_To_Pointer) 173 FromType = Context.getArrayDecayedType(FromType); 174 175 if (Second == ICK_Pointer_Conversion) 176 if (const PointerType* ToPtrType = ToType->getAsPointerType()) 177 return ToPtrType->getPointeeType()->isVoidType(); 178 179 return false; 180} 181 182/// DebugPrint - Print this standard conversion sequence to standard 183/// error. Useful for debugging overloading issues. 184void StandardConversionSequence::DebugPrint() const { 185 bool PrintedSomething = false; 186 if (First != ICK_Identity) { 187 fprintf(stderr, "%s", GetImplicitConversionName(First)); 188 PrintedSomething = true; 189 } 190 191 if (Second != ICK_Identity) { 192 if (PrintedSomething) { 193 fprintf(stderr, " -> "); 194 } 195 fprintf(stderr, "%s", GetImplicitConversionName(Second)); 196 197 if (CopyConstructor) { 198 fprintf(stderr, " (by copy constructor)"); 199 } else if (DirectBinding) { 200 fprintf(stderr, " (direct reference binding)"); 201 } else if (ReferenceBinding) { 202 fprintf(stderr, " (reference binding)"); 203 } 204 PrintedSomething = true; 205 } 206 207 if (Third != ICK_Identity) { 208 if (PrintedSomething) { 209 fprintf(stderr, " -> "); 210 } 211 fprintf(stderr, "%s", GetImplicitConversionName(Third)); 212 PrintedSomething = true; 213 } 214 215 if (!PrintedSomething) { 216 fprintf(stderr, "No conversions required"); 217 } 218} 219 220/// DebugPrint - Print this user-defined conversion sequence to standard 221/// error. Useful for debugging overloading issues. 222void UserDefinedConversionSequence::DebugPrint() const { 223 if (Before.First || Before.Second || Before.Third) { 224 Before.DebugPrint(); 225 fprintf(stderr, " -> "); 226 } 227 fprintf(stderr, "'%s'", ConversionFunction->getNameAsString().c_str()); 228 if (After.First || After.Second || After.Third) { 229 fprintf(stderr, " -> "); 230 After.DebugPrint(); 231 } 232} 233 234/// DebugPrint - Print this implicit conversion sequence to standard 235/// error. Useful for debugging overloading issues. 236void ImplicitConversionSequence::DebugPrint() const { 237 switch (ConversionKind) { 238 case StandardConversion: 239 fprintf(stderr, "Standard conversion: "); 240 Standard.DebugPrint(); 241 break; 242 case UserDefinedConversion: 243 fprintf(stderr, "User-defined conversion: "); 244 UserDefined.DebugPrint(); 245 break; 246 case EllipsisConversion: 247 fprintf(stderr, "Ellipsis conversion"); 248 break; 249 case BadConversion: 250 fprintf(stderr, "Bad conversion"); 251 break; 252 } 253 254 fprintf(stderr, "\n"); 255} 256 257// IsOverload - Determine whether the given New declaration is an 258// overload of the Old declaration. This routine returns false if New 259// and Old cannot be overloaded, e.g., if they are functions with the 260// same signature (C++ 1.3.10) or if the Old declaration isn't a 261// function (or overload set). When it does return false and Old is an 262// OverloadedFunctionDecl, MatchedDecl will be set to point to the 263// FunctionDecl that New cannot be overloaded with. 264// 265// Example: Given the following input: 266// 267// void f(int, float); // #1 268// void f(int, int); // #2 269// int f(int, int); // #3 270// 271// When we process #1, there is no previous declaration of "f", 272// so IsOverload will not be used. 273// 274// When we process #2, Old is a FunctionDecl for #1. By comparing the 275// parameter types, we see that #1 and #2 are overloaded (since they 276// have different signatures), so this routine returns false; 277// MatchedDecl is unchanged. 278// 279// When we process #3, Old is an OverloadedFunctionDecl containing #1 280// and #2. We compare the signatures of #3 to #1 (they're overloaded, 281// so we do nothing) and then #3 to #2. Since the signatures of #3 and 282// #2 are identical (return types of functions are not part of the 283// signature), IsOverload returns false and MatchedDecl will be set to 284// point to the FunctionDecl for #2. 285bool 286Sema::IsOverload(FunctionDecl *New, Decl* OldD, 287 OverloadedFunctionDecl::function_iterator& MatchedDecl) 288{ 289 if (OverloadedFunctionDecl* Ovl = dyn_cast<OverloadedFunctionDecl>(OldD)) { 290 // Is this new function an overload of every function in the 291 // overload set? 292 OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 293 FuncEnd = Ovl->function_end(); 294 for (; Func != FuncEnd; ++Func) { 295 if (!IsOverload(New, *Func, MatchedDecl)) { 296 MatchedDecl = Func; 297 return false; 298 } 299 } 300 301 // This function overloads every function in the overload set. 302 return true; 303 } else if (FunctionDecl* Old = dyn_cast<FunctionDecl>(OldD)) { 304 // Is the function New an overload of the function Old? 305 QualType OldQType = Context.getCanonicalType(Old->getType()); 306 QualType NewQType = Context.getCanonicalType(New->getType()); 307 308 // Compare the signatures (C++ 1.3.10) of the two functions to 309 // determine whether they are overloads. If we find any mismatch 310 // in the signature, they are overloads. 311 312 // If either of these functions is a K&R-style function (no 313 // prototype), then we consider them to have matching signatures. 314 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) || 315 isa<FunctionNoProtoType>(NewQType.getTypePtr())) 316 return false; 317 318 FunctionProtoType* OldType = cast<FunctionProtoType>(OldQType.getTypePtr()); 319 FunctionProtoType* NewType = cast<FunctionProtoType>(NewQType.getTypePtr()); 320 321 // The signature of a function includes the types of its 322 // parameters (C++ 1.3.10), which includes the presence or absence 323 // of the ellipsis; see C++ DR 357). 324 if (OldQType != NewQType && 325 (OldType->getNumArgs() != NewType->getNumArgs() || 326 OldType->isVariadic() != NewType->isVariadic() || 327 !std::equal(OldType->arg_type_begin(), OldType->arg_type_end(), 328 NewType->arg_type_begin()))) 329 return true; 330 331 // If the function is a class member, its signature includes the 332 // cv-qualifiers (if any) on the function itself. 333 // 334 // As part of this, also check whether one of the member functions 335 // is static, in which case they are not overloads (C++ 336 // 13.1p2). While not part of the definition of the signature, 337 // this check is important to determine whether these functions 338 // can be overloaded. 339 CXXMethodDecl* OldMethod = dyn_cast<CXXMethodDecl>(Old); 340 CXXMethodDecl* NewMethod = dyn_cast<CXXMethodDecl>(New); 341 if (OldMethod && NewMethod && 342 !OldMethod->isStatic() && !NewMethod->isStatic() && 343 OldMethod->getTypeQualifiers() != NewMethod->getTypeQualifiers()) 344 return true; 345 346 // The signatures match; this is not an overload. 347 return false; 348 } else { 349 // (C++ 13p1): 350 // Only function declarations can be overloaded; object and type 351 // declarations cannot be overloaded. 352 return false; 353 } 354} 355 356/// TryImplicitConversion - Attempt to perform an implicit conversion 357/// from the given expression (Expr) to the given type (ToType). This 358/// function returns an implicit conversion sequence that can be used 359/// to perform the initialization. Given 360/// 361/// void f(float f); 362/// void g(int i) { f(i); } 363/// 364/// this routine would produce an implicit conversion sequence to 365/// describe the initialization of f from i, which will be a standard 366/// conversion sequence containing an lvalue-to-rvalue conversion (C++ 367/// 4.1) followed by a floating-integral conversion (C++ 4.9). 368// 369/// Note that this routine only determines how the conversion can be 370/// performed; it does not actually perform the conversion. As such, 371/// it will not produce any diagnostics if no conversion is available, 372/// but will instead return an implicit conversion sequence of kind 373/// "BadConversion". 374/// 375/// If @p SuppressUserConversions, then user-defined conversions are 376/// not permitted. 377/// If @p AllowExplicit, then explicit user-defined conversions are 378/// permitted. 379ImplicitConversionSequence 380Sema::TryImplicitConversion(Expr* From, QualType ToType, 381 bool SuppressUserConversions, 382 bool AllowExplicit) 383{ 384 ImplicitConversionSequence ICS; 385 if (IsStandardConversion(From, ToType, ICS.Standard)) 386 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 387 else if (getLangOptions().CPlusPlus && 388 IsUserDefinedConversion(From, ToType, ICS.UserDefined, 389 !SuppressUserConversions, AllowExplicit)) { 390 ICS.ConversionKind = ImplicitConversionSequence::UserDefinedConversion; 391 // C++ [over.ics.user]p4: 392 // A conversion of an expression of class type to the same class 393 // type is given Exact Match rank, and a conversion of an 394 // expression of class type to a base class of that type is 395 // given Conversion rank, in spite of the fact that a copy 396 // constructor (i.e., a user-defined conversion function) is 397 // called for those cases. 398 if (CXXConstructorDecl *Constructor 399 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) { 400 QualType FromCanon 401 = Context.getCanonicalType(From->getType().getUnqualifiedType()); 402 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType(); 403 if (FromCanon == ToCanon || IsDerivedFrom(FromCanon, ToCanon)) { 404 // Turn this into a "standard" conversion sequence, so that it 405 // gets ranked with standard conversion sequences. 406 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 407 ICS.Standard.setAsIdentityConversion(); 408 ICS.Standard.FromTypePtr = From->getType().getAsOpaquePtr(); 409 ICS.Standard.ToTypePtr = ToType.getAsOpaquePtr(); 410 ICS.Standard.CopyConstructor = Constructor; 411 if (ToCanon != FromCanon) 412 ICS.Standard.Second = ICK_Derived_To_Base; 413 } 414 } 415 416 // C++ [over.best.ics]p4: 417 // However, when considering the argument of a user-defined 418 // conversion function that is a candidate by 13.3.1.3 when 419 // invoked for the copying of the temporary in the second step 420 // of a class copy-initialization, or by 13.3.1.4, 13.3.1.5, or 421 // 13.3.1.6 in all cases, only standard conversion sequences and 422 // ellipsis conversion sequences are allowed. 423 if (SuppressUserConversions && 424 ICS.ConversionKind == ImplicitConversionSequence::UserDefinedConversion) 425 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 426 } else 427 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 428 429 return ICS; 430} 431 432/// IsStandardConversion - Determines whether there is a standard 433/// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the 434/// expression From to the type ToType. Standard conversion sequences 435/// only consider non-class types; for conversions that involve class 436/// types, use TryImplicitConversion. If a conversion exists, SCS will 437/// contain the standard conversion sequence required to perform this 438/// conversion and this routine will return true. Otherwise, this 439/// routine will return false and the value of SCS is unspecified. 440bool 441Sema::IsStandardConversion(Expr* From, QualType ToType, 442 StandardConversionSequence &SCS) 443{ 444 QualType FromType = From->getType(); 445 446 // Standard conversions (C++ [conv]) 447 SCS.setAsIdentityConversion(); 448 SCS.Deprecated = false; 449 SCS.IncompatibleObjC = false; 450 SCS.FromTypePtr = FromType.getAsOpaquePtr(); 451 SCS.CopyConstructor = 0; 452 453 // There are no standard conversions for class types in C++, so 454 // abort early. When overloading in C, however, we do permit 455 if (FromType->isRecordType() || ToType->isRecordType()) { 456 if (getLangOptions().CPlusPlus) 457 return false; 458 459 // When we're overloading in C, we allow, as standard conversions, 460 } 461 462 // The first conversion can be an lvalue-to-rvalue conversion, 463 // array-to-pointer conversion, or function-to-pointer conversion 464 // (C++ 4p1). 465 466 // Lvalue-to-rvalue conversion (C++ 4.1): 467 // An lvalue (3.10) of a non-function, non-array type T can be 468 // converted to an rvalue. 469 Expr::isLvalueResult argIsLvalue = From->isLvalue(Context); 470 if (argIsLvalue == Expr::LV_Valid && 471 !FromType->isFunctionType() && !FromType->isArrayType() && 472 Context.getCanonicalType(FromType) != Context.OverloadTy) { 473 SCS.First = ICK_Lvalue_To_Rvalue; 474 475 // If T is a non-class type, the type of the rvalue is the 476 // cv-unqualified version of T. Otherwise, the type of the rvalue 477 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we 478 // just strip the qualifiers because they don't matter. 479 480 // FIXME: Doesn't see through to qualifiers behind a typedef! 481 FromType = FromType.getUnqualifiedType(); 482 } 483 // Array-to-pointer conversion (C++ 4.2) 484 else if (FromType->isArrayType()) { 485 SCS.First = ICK_Array_To_Pointer; 486 487 // An lvalue or rvalue of type "array of N T" or "array of unknown 488 // bound of T" can be converted to an rvalue of type "pointer to 489 // T" (C++ 4.2p1). 490 FromType = Context.getArrayDecayedType(FromType); 491 492 if (IsStringLiteralToNonConstPointerConversion(From, ToType)) { 493 // This conversion is deprecated. (C++ D.4). 494 SCS.Deprecated = true; 495 496 // For the purpose of ranking in overload resolution 497 // (13.3.3.1.1), this conversion is considered an 498 // array-to-pointer conversion followed by a qualification 499 // conversion (4.4). (C++ 4.2p2) 500 SCS.Second = ICK_Identity; 501 SCS.Third = ICK_Qualification; 502 SCS.ToTypePtr = ToType.getAsOpaquePtr(); 503 return true; 504 } 505 } 506 // Function-to-pointer conversion (C++ 4.3). 507 else if (FromType->isFunctionType() && argIsLvalue == Expr::LV_Valid) { 508 SCS.First = ICK_Function_To_Pointer; 509 510 // An lvalue of function type T can be converted to an rvalue of 511 // type "pointer to T." The result is a pointer to the 512 // function. (C++ 4.3p1). 513 FromType = Context.getPointerType(FromType); 514 } 515 // Address of overloaded function (C++ [over.over]). 516 else if (FunctionDecl *Fn 517 = ResolveAddressOfOverloadedFunction(From, ToType, false)) { 518 SCS.First = ICK_Function_To_Pointer; 519 520 // We were able to resolve the address of the overloaded function, 521 // so we can convert to the type of that function. 522 FromType = Fn->getType(); 523 if (ToType->isLValueReferenceType()) 524 FromType = Context.getLValueReferenceType(FromType); 525 else if (ToType->isRValueReferenceType()) 526 FromType = Context.getRValueReferenceType(FromType); 527 else if (ToType->isMemberPointerType()) { 528 // Resolve address only succeeds if both sides are member pointers, 529 // but it doesn't have to be the same class. See DR 247. 530 // Note that this means that the type of &Derived::fn can be 531 // Ret (Base::*)(Args) if the fn overload actually found is from the 532 // base class, even if it was brought into the derived class via a 533 // using declaration. The standard isn't clear on this issue at all. 534 CXXMethodDecl *M = cast<CXXMethodDecl>(Fn); 535 FromType = Context.getMemberPointerType(FromType, 536 Context.getTypeDeclType(M->getParent()).getTypePtr()); 537 } else 538 FromType = Context.getPointerType(FromType); 539 } 540 // We don't require any conversions for the first step. 541 else { 542 SCS.First = ICK_Identity; 543 } 544 545 // The second conversion can be an integral promotion, floating 546 // point promotion, integral conversion, floating point conversion, 547 // floating-integral conversion, pointer conversion, 548 // pointer-to-member conversion, or boolean conversion (C++ 4p1). 549 // For overloading in C, this can also be a "compatible-type" 550 // conversion. 551 bool IncompatibleObjC = false; 552 if (Context.hasSameUnqualifiedType(FromType, ToType)) { 553 // The unqualified versions of the types are the same: there's no 554 // conversion to do. 555 SCS.Second = ICK_Identity; 556 } 557 // Integral promotion (C++ 4.5). 558 else if (IsIntegralPromotion(From, FromType, ToType)) { 559 SCS.Second = ICK_Integral_Promotion; 560 FromType = ToType.getUnqualifiedType(); 561 } 562 // Floating point promotion (C++ 4.6). 563 else if (IsFloatingPointPromotion(FromType, ToType)) { 564 SCS.Second = ICK_Floating_Promotion; 565 FromType = ToType.getUnqualifiedType(); 566 } 567 // Complex promotion (Clang extension) 568 else if (IsComplexPromotion(FromType, ToType)) { 569 SCS.Second = ICK_Complex_Promotion; 570 FromType = ToType.getUnqualifiedType(); 571 } 572 // Integral conversions (C++ 4.7). 573 // FIXME: isIntegralType shouldn't be true for enums in C++. 574 else if ((FromType->isIntegralType() || FromType->isEnumeralType()) && 575 (ToType->isIntegralType() && !ToType->isEnumeralType())) { 576 SCS.Second = ICK_Integral_Conversion; 577 FromType = ToType.getUnqualifiedType(); 578 } 579 // Floating point conversions (C++ 4.8). 580 else if (FromType->isFloatingType() && ToType->isFloatingType()) { 581 SCS.Second = ICK_Floating_Conversion; 582 FromType = ToType.getUnqualifiedType(); 583 } 584 // Complex conversions (C99 6.3.1.6) 585 else if (FromType->isComplexType() && ToType->isComplexType()) { 586 SCS.Second = ICK_Complex_Conversion; 587 FromType = ToType.getUnqualifiedType(); 588 } 589 // Floating-integral conversions (C++ 4.9). 590 // FIXME: isIntegralType shouldn't be true for enums in C++. 591 else if ((FromType->isFloatingType() && 592 ToType->isIntegralType() && !ToType->isBooleanType() && 593 !ToType->isEnumeralType()) || 594 ((FromType->isIntegralType() || FromType->isEnumeralType()) && 595 ToType->isFloatingType())) { 596 SCS.Second = ICK_Floating_Integral; 597 FromType = ToType.getUnqualifiedType(); 598 } 599 // Complex-real conversions (C99 6.3.1.7) 600 else if ((FromType->isComplexType() && ToType->isArithmeticType()) || 601 (ToType->isComplexType() && FromType->isArithmeticType())) { 602 SCS.Second = ICK_Complex_Real; 603 FromType = ToType.getUnqualifiedType(); 604 } 605 // Pointer conversions (C++ 4.10). 606 else if (IsPointerConversion(From, FromType, ToType, FromType, 607 IncompatibleObjC)) { 608 SCS.Second = ICK_Pointer_Conversion; 609 SCS.IncompatibleObjC = IncompatibleObjC; 610 } 611 // Pointer to member conversions (4.11). 612 else if (IsMemberPointerConversion(From, FromType, ToType, FromType)) { 613 SCS.Second = ICK_Pointer_Member; 614 } 615 // Boolean conversions (C++ 4.12). 616 else if (ToType->isBooleanType() && 617 (FromType->isArithmeticType() || 618 FromType->isEnumeralType() || 619 FromType->isPointerType() || 620 FromType->isBlockPointerType() || 621 FromType->isMemberPointerType())) { 622 SCS.Second = ICK_Boolean_Conversion; 623 FromType = Context.BoolTy; 624 } 625 // Compatible conversions (Clang extension for C function overloading) 626 else if (!getLangOptions().CPlusPlus && 627 Context.typesAreCompatible(ToType, FromType)) { 628 SCS.Second = ICK_Compatible_Conversion; 629 } else { 630 // No second conversion required. 631 SCS.Second = ICK_Identity; 632 } 633 634 QualType CanonFrom; 635 QualType CanonTo; 636 // The third conversion can be a qualification conversion (C++ 4p1). 637 if (IsQualificationConversion(FromType, ToType)) { 638 SCS.Third = ICK_Qualification; 639 FromType = ToType; 640 CanonFrom = Context.getCanonicalType(FromType); 641 CanonTo = Context.getCanonicalType(ToType); 642 } else { 643 // No conversion required 644 SCS.Third = ICK_Identity; 645 646 // C++ [over.best.ics]p6: 647 // [...] Any difference in top-level cv-qualification is 648 // subsumed by the initialization itself and does not constitute 649 // a conversion. [...] 650 CanonFrom = Context.getCanonicalType(FromType); 651 CanonTo = Context.getCanonicalType(ToType); 652 if (CanonFrom.getUnqualifiedType() == CanonTo.getUnqualifiedType() && 653 CanonFrom.getCVRQualifiers() != CanonTo.getCVRQualifiers()) { 654 FromType = ToType; 655 CanonFrom = CanonTo; 656 } 657 } 658 659 // If we have not converted the argument type to the parameter type, 660 // this is a bad conversion sequence. 661 if (CanonFrom != CanonTo) 662 return false; 663 664 SCS.ToTypePtr = FromType.getAsOpaquePtr(); 665 return true; 666} 667 668/// IsIntegralPromotion - Determines whether the conversion from the 669/// expression From (whose potentially-adjusted type is FromType) to 670/// ToType is an integral promotion (C++ 4.5). If so, returns true and 671/// sets PromotedType to the promoted type. 672bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) 673{ 674 const BuiltinType *To = ToType->getAsBuiltinType(); 675 // All integers are built-in. 676 if (!To) { 677 return false; 678 } 679 680 // An rvalue of type char, signed char, unsigned char, short int, or 681 // unsigned short int can be converted to an rvalue of type int if 682 // int can represent all the values of the source type; otherwise, 683 // the source rvalue can be converted to an rvalue of type unsigned 684 // int (C++ 4.5p1). 685 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType()) { 686 if (// We can promote any signed, promotable integer type to an int 687 (FromType->isSignedIntegerType() || 688 // We can promote any unsigned integer type whose size is 689 // less than int to an int. 690 (!FromType->isSignedIntegerType() && 691 Context.getTypeSize(FromType) < Context.getTypeSize(ToType)))) { 692 return To->getKind() == BuiltinType::Int; 693 } 694 695 return To->getKind() == BuiltinType::UInt; 696 } 697 698 // An rvalue of type wchar_t (3.9.1) or an enumeration type (7.2) 699 // can be converted to an rvalue of the first of the following types 700 // that can represent all the values of its underlying type: int, 701 // unsigned int, long, or unsigned long (C++ 4.5p2). 702 if ((FromType->isEnumeralType() || FromType->isWideCharType()) 703 && ToType->isIntegerType()) { 704 // Determine whether the type we're converting from is signed or 705 // unsigned. 706 bool FromIsSigned; 707 uint64_t FromSize = Context.getTypeSize(FromType); 708 if (const EnumType *FromEnumType = FromType->getAsEnumType()) { 709 QualType UnderlyingType = FromEnumType->getDecl()->getIntegerType(); 710 FromIsSigned = UnderlyingType->isSignedIntegerType(); 711 } else { 712 // FIXME: Is wchar_t signed or unsigned? We assume it's signed for now. 713 FromIsSigned = true; 714 } 715 716 // The types we'll try to promote to, in the appropriate 717 // order. Try each of these types. 718 QualType PromoteTypes[6] = { 719 Context.IntTy, Context.UnsignedIntTy, 720 Context.LongTy, Context.UnsignedLongTy , 721 Context.LongLongTy, Context.UnsignedLongLongTy 722 }; 723 for (int Idx = 0; Idx < 6; ++Idx) { 724 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]); 725 if (FromSize < ToSize || 726 (FromSize == ToSize && 727 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) { 728 // We found the type that we can promote to. If this is the 729 // type we wanted, we have a promotion. Otherwise, no 730 // promotion. 731 return Context.getCanonicalType(ToType).getUnqualifiedType() 732 == Context.getCanonicalType(PromoteTypes[Idx]).getUnqualifiedType(); 733 } 734 } 735 } 736 737 // An rvalue for an integral bit-field (9.6) can be converted to an 738 // rvalue of type int if int can represent all the values of the 739 // bit-field; otherwise, it can be converted to unsigned int if 740 // unsigned int can represent all the values of the bit-field. If 741 // the bit-field is larger yet, no integral promotion applies to 742 // it. If the bit-field has an enumerated type, it is treated as any 743 // other value of that type for promotion purposes (C++ 4.5p3). 744 // FIXME: We should delay checking of bit-fields until we actually 745 // perform the conversion. 746 if (MemberExpr *MemRef = dyn_cast_or_null<MemberExpr>(From)) { 747 using llvm::APSInt; 748 if (FieldDecl *MemberDecl = dyn_cast<FieldDecl>(MemRef->getMemberDecl())) { 749 APSInt BitWidth; 750 if (MemberDecl->isBitField() && 751 FromType->isIntegralType() && !FromType->isEnumeralType() && 752 From->isIntegerConstantExpr(BitWidth, Context)) { 753 APSInt ToSize(Context.getTypeSize(ToType)); 754 755 // Are we promoting to an int from a bitfield that fits in an int? 756 if (BitWidth < ToSize || 757 (FromType->isSignedIntegerType() && BitWidth <= ToSize)) { 758 return To->getKind() == BuiltinType::Int; 759 } 760 761 // Are we promoting to an unsigned int from an unsigned bitfield 762 // that fits into an unsigned int? 763 if (FromType->isUnsignedIntegerType() && BitWidth <= ToSize) { 764 return To->getKind() == BuiltinType::UInt; 765 } 766 767 return false; 768 } 769 } 770 } 771 772 // An rvalue of type bool can be converted to an rvalue of type int, 773 // with false becoming zero and true becoming one (C++ 4.5p4). 774 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) { 775 return true; 776 } 777 778 return false; 779} 780 781/// IsFloatingPointPromotion - Determines whether the conversion from 782/// FromType to ToType is a floating point promotion (C++ 4.6). If so, 783/// returns true and sets PromotedType to the promoted type. 784bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) 785{ 786 /// An rvalue of type float can be converted to an rvalue of type 787 /// double. (C++ 4.6p1). 788 if (const BuiltinType *FromBuiltin = FromType->getAsBuiltinType()) 789 if (const BuiltinType *ToBuiltin = ToType->getAsBuiltinType()) { 790 if (FromBuiltin->getKind() == BuiltinType::Float && 791 ToBuiltin->getKind() == BuiltinType::Double) 792 return true; 793 794 // C99 6.3.1.5p1: 795 // When a float is promoted to double or long double, or a 796 // double is promoted to long double [...]. 797 if (!getLangOptions().CPlusPlus && 798 (FromBuiltin->getKind() == BuiltinType::Float || 799 FromBuiltin->getKind() == BuiltinType::Double) && 800 (ToBuiltin->getKind() == BuiltinType::LongDouble)) 801 return true; 802 } 803 804 return false; 805} 806 807/// \brief Determine if a conversion is a complex promotion. 808/// 809/// A complex promotion is defined as a complex -> complex conversion 810/// where the conversion between the underlying real types is a 811/// floating-point or integral promotion. 812bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) { 813 const ComplexType *FromComplex = FromType->getAsComplexType(); 814 if (!FromComplex) 815 return false; 816 817 const ComplexType *ToComplex = ToType->getAsComplexType(); 818 if (!ToComplex) 819 return false; 820 821 return IsFloatingPointPromotion(FromComplex->getElementType(), 822 ToComplex->getElementType()) || 823 IsIntegralPromotion(0, FromComplex->getElementType(), 824 ToComplex->getElementType()); 825} 826 827/// BuildSimilarlyQualifiedPointerType - In a pointer conversion from 828/// the pointer type FromPtr to a pointer to type ToPointee, with the 829/// same type qualifiers as FromPtr has on its pointee type. ToType, 830/// if non-empty, will be a pointer to ToType that may or may not have 831/// the right set of qualifiers on its pointee. 832static QualType 833BuildSimilarlyQualifiedPointerType(const PointerType *FromPtr, 834 QualType ToPointee, QualType ToType, 835 ASTContext &Context) { 836 QualType CanonFromPointee = Context.getCanonicalType(FromPtr->getPointeeType()); 837 QualType CanonToPointee = Context.getCanonicalType(ToPointee); 838 unsigned Quals = CanonFromPointee.getCVRQualifiers(); 839 840 // Exact qualifier match -> return the pointer type we're converting to. 841 if (CanonToPointee.getCVRQualifiers() == Quals) { 842 // ToType is exactly what we need. Return it. 843 if (ToType.getTypePtr()) 844 return ToType; 845 846 // Build a pointer to ToPointee. It has the right qualifiers 847 // already. 848 return Context.getPointerType(ToPointee); 849 } 850 851 // Just build a canonical type that has the right qualifiers. 852 return Context.getPointerType(CanonToPointee.getQualifiedType(Quals)); 853} 854 855/// IsPointerConversion - Determines whether the conversion of the 856/// expression From, which has the (possibly adjusted) type FromType, 857/// can be converted to the type ToType via a pointer conversion (C++ 858/// 4.10). If so, returns true and places the converted type (that 859/// might differ from ToType in its cv-qualifiers at some level) into 860/// ConvertedType. 861/// 862/// This routine also supports conversions to and from block pointers 863/// and conversions with Objective-C's 'id', 'id<protocols...>', and 864/// pointers to interfaces. FIXME: Once we've determined the 865/// appropriate overloading rules for Objective-C, we may want to 866/// split the Objective-C checks into a different routine; however, 867/// GCC seems to consider all of these conversions to be pointer 868/// conversions, so for now they live here. IncompatibleObjC will be 869/// set if the conversion is an allowed Objective-C conversion that 870/// should result in a warning. 871bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType, 872 QualType& ConvertedType, 873 bool &IncompatibleObjC) 874{ 875 IncompatibleObjC = false; 876 if (isObjCPointerConversion(FromType, ToType, ConvertedType, IncompatibleObjC)) 877 return true; 878 879 // Conversion from a null pointer constant to any Objective-C pointer type. 880 if (Context.isObjCObjectPointerType(ToType) && 881 From->isNullPointerConstant(Context)) { 882 ConvertedType = ToType; 883 return true; 884 } 885 886 // Blocks: Block pointers can be converted to void*. 887 if (FromType->isBlockPointerType() && ToType->isPointerType() && 888 ToType->getAsPointerType()->getPointeeType()->isVoidType()) { 889 ConvertedType = ToType; 890 return true; 891 } 892 // Blocks: A null pointer constant can be converted to a block 893 // pointer type. 894 if (ToType->isBlockPointerType() && From->isNullPointerConstant(Context)) { 895 ConvertedType = ToType; 896 return true; 897 } 898 899 const PointerType* ToTypePtr = ToType->getAsPointerType(); 900 if (!ToTypePtr) 901 return false; 902 903 // A null pointer constant can be converted to a pointer type (C++ 4.10p1). 904 if (From->isNullPointerConstant(Context)) { 905 ConvertedType = ToType; 906 return true; 907 } 908 909 // Beyond this point, both types need to be pointers. 910 const PointerType *FromTypePtr = FromType->getAsPointerType(); 911 if (!FromTypePtr) 912 return false; 913 914 QualType FromPointeeType = FromTypePtr->getPointeeType(); 915 QualType ToPointeeType = ToTypePtr->getPointeeType(); 916 917 // An rvalue of type "pointer to cv T," where T is an object type, 918 // can be converted to an rvalue of type "pointer to cv void" (C++ 919 // 4.10p2). 920 if (FromPointeeType->isObjectType() && ToPointeeType->isVoidType()) { 921 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 922 ToPointeeType, 923 ToType, Context); 924 return true; 925 } 926 927 // When we're overloading in C, we allow a special kind of pointer 928 // conversion for compatible-but-not-identical pointee types. 929 if (!getLangOptions().CPlusPlus && 930 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) { 931 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 932 ToPointeeType, 933 ToType, Context); 934 return true; 935 } 936 937 // C++ [conv.ptr]p3: 938 // 939 // An rvalue of type "pointer to cv D," where D is a class type, 940 // can be converted to an rvalue of type "pointer to cv B," where 941 // B is a base class (clause 10) of D. If B is an inaccessible 942 // (clause 11) or ambiguous (10.2) base class of D, a program that 943 // necessitates this conversion is ill-formed. The result of the 944 // conversion is a pointer to the base class sub-object of the 945 // derived class object. The null pointer value is converted to 946 // the null pointer value of the destination type. 947 // 948 // Note that we do not check for ambiguity or inaccessibility 949 // here. That is handled by CheckPointerConversion. 950 if (getLangOptions().CPlusPlus && 951 FromPointeeType->isRecordType() && ToPointeeType->isRecordType() && 952 IsDerivedFrom(FromPointeeType, ToPointeeType)) { 953 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 954 ToPointeeType, 955 ToType, Context); 956 return true; 957 } 958 959 return false; 960} 961 962/// isObjCPointerConversion - Determines whether this is an 963/// Objective-C pointer conversion. Subroutine of IsPointerConversion, 964/// with the same arguments and return values. 965bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType, 966 QualType& ConvertedType, 967 bool &IncompatibleObjC) { 968 if (!getLangOptions().ObjC1) 969 return false; 970 971 // Conversions with Objective-C's id<...>. 972 if ((FromType->isObjCQualifiedIdType() || ToType->isObjCQualifiedIdType()) && 973 ObjCQualifiedIdTypesAreCompatible(ToType, FromType, /*compare=*/false)) { 974 ConvertedType = ToType; 975 return true; 976 } 977 978 // Beyond this point, both types need to be pointers or block pointers. 979 QualType ToPointeeType; 980 const PointerType* ToTypePtr = ToType->getAsPointerType(); 981 if (ToTypePtr) 982 ToPointeeType = ToTypePtr->getPointeeType(); 983 else if (const BlockPointerType *ToBlockPtr = ToType->getAsBlockPointerType()) 984 ToPointeeType = ToBlockPtr->getPointeeType(); 985 else 986 return false; 987 988 QualType FromPointeeType; 989 const PointerType *FromTypePtr = FromType->getAsPointerType(); 990 if (FromTypePtr) 991 FromPointeeType = FromTypePtr->getPointeeType(); 992 else if (const BlockPointerType *FromBlockPtr 993 = FromType->getAsBlockPointerType()) 994 FromPointeeType = FromBlockPtr->getPointeeType(); 995 else 996 return false; 997 998 // Objective C++: We're able to convert from a pointer to an 999 // interface to a pointer to a different interface. 1000 const ObjCInterfaceType* FromIface = FromPointeeType->getAsObjCInterfaceType(); 1001 const ObjCInterfaceType* ToIface = ToPointeeType->getAsObjCInterfaceType(); 1002 if (FromIface && ToIface && 1003 Context.canAssignObjCInterfaces(ToIface, FromIface)) { 1004 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1005 ToPointeeType, 1006 ToType, Context); 1007 return true; 1008 } 1009 1010 if (FromIface && ToIface && 1011 Context.canAssignObjCInterfaces(FromIface, ToIface)) { 1012 // Okay: this is some kind of implicit downcast of Objective-C 1013 // interfaces, which is permitted. However, we're going to 1014 // complain about it. 1015 IncompatibleObjC = true; 1016 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1017 ToPointeeType, 1018 ToType, Context); 1019 return true; 1020 } 1021 1022 // Objective C++: We're able to convert between "id" and a pointer 1023 // to any interface (in both directions). 1024 if ((FromIface && Context.isObjCIdStructType(ToPointeeType)) 1025 || (ToIface && Context.isObjCIdStructType(FromPointeeType))) { 1026 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr, 1027 ToPointeeType, 1028 ToType, Context); 1029 return true; 1030 } 1031 1032 // Objective C++: Allow conversions between the Objective-C "id" and 1033 // "Class", in either direction. 1034 if ((Context.isObjCIdStructType(FromPointeeType) && 1035 Context.isObjCClassStructType(ToPointeeType)) || 1036 (Context.isObjCClassStructType(FromPointeeType) && 1037 Context.isObjCIdStructType(ToPointeeType))) { 1038 ConvertedType = ToType; 1039 return true; 1040 } 1041 1042 // If we have pointers to pointers, recursively check whether this 1043 // is an Objective-C conversion. 1044 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() && 1045 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType, 1046 IncompatibleObjC)) { 1047 // We always complain about this conversion. 1048 IncompatibleObjC = true; 1049 ConvertedType = ToType; 1050 return true; 1051 } 1052 1053 // If we have pointers to functions or blocks, check whether the only 1054 // differences in the argument and result types are in Objective-C 1055 // pointer conversions. If so, we permit the conversion (but 1056 // complain about it). 1057 const FunctionProtoType *FromFunctionType 1058 = FromPointeeType->getAsFunctionProtoType(); 1059 const FunctionProtoType *ToFunctionType 1060 = ToPointeeType->getAsFunctionProtoType(); 1061 if (FromFunctionType && ToFunctionType) { 1062 // If the function types are exactly the same, this isn't an 1063 // Objective-C pointer conversion. 1064 if (Context.getCanonicalType(FromPointeeType) 1065 == Context.getCanonicalType(ToPointeeType)) 1066 return false; 1067 1068 // Perform the quick checks that will tell us whether these 1069 // function types are obviously different. 1070 if (FromFunctionType->getNumArgs() != ToFunctionType->getNumArgs() || 1071 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() || 1072 FromFunctionType->getTypeQuals() != ToFunctionType->getTypeQuals()) 1073 return false; 1074 1075 bool HasObjCConversion = false; 1076 if (Context.getCanonicalType(FromFunctionType->getResultType()) 1077 == Context.getCanonicalType(ToFunctionType->getResultType())) { 1078 // Okay, the types match exactly. Nothing to do. 1079 } else if (isObjCPointerConversion(FromFunctionType->getResultType(), 1080 ToFunctionType->getResultType(), 1081 ConvertedType, IncompatibleObjC)) { 1082 // Okay, we have an Objective-C pointer conversion. 1083 HasObjCConversion = true; 1084 } else { 1085 // Function types are too different. Abort. 1086 return false; 1087 } 1088 1089 // Check argument types. 1090 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumArgs(); 1091 ArgIdx != NumArgs; ++ArgIdx) { 1092 QualType FromArgType = FromFunctionType->getArgType(ArgIdx); 1093 QualType ToArgType = ToFunctionType->getArgType(ArgIdx); 1094 if (Context.getCanonicalType(FromArgType) 1095 == Context.getCanonicalType(ToArgType)) { 1096 // Okay, the types match exactly. Nothing to do. 1097 } else if (isObjCPointerConversion(FromArgType, ToArgType, 1098 ConvertedType, IncompatibleObjC)) { 1099 // Okay, we have an Objective-C pointer conversion. 1100 HasObjCConversion = true; 1101 } else { 1102 // Argument types are too different. Abort. 1103 return false; 1104 } 1105 } 1106 1107 if (HasObjCConversion) { 1108 // We had an Objective-C conversion. Allow this pointer 1109 // conversion, but complain about it. 1110 ConvertedType = ToType; 1111 IncompatibleObjC = true; 1112 return true; 1113 } 1114 } 1115 1116 return false; 1117} 1118 1119/// CheckPointerConversion - Check the pointer conversion from the 1120/// expression From to the type ToType. This routine checks for 1121/// ambiguous (FIXME: or inaccessible) derived-to-base pointer 1122/// conversions for which IsPointerConversion has already returned 1123/// true. It returns true and produces a diagnostic if there was an 1124/// error, or returns false otherwise. 1125bool Sema::CheckPointerConversion(Expr *From, QualType ToType) { 1126 QualType FromType = From->getType(); 1127 1128 if (const PointerType *FromPtrType = FromType->getAsPointerType()) 1129 if (const PointerType *ToPtrType = ToType->getAsPointerType()) { 1130 QualType FromPointeeType = FromPtrType->getPointeeType(), 1131 ToPointeeType = ToPtrType->getPointeeType(); 1132 1133 // Objective-C++ conversions are always okay. 1134 // FIXME: We should have a different class of conversions for 1135 // the Objective-C++ implicit conversions. 1136 if (Context.isObjCIdStructType(FromPointeeType) || 1137 Context.isObjCIdStructType(ToPointeeType) || 1138 Context.isObjCClassStructType(FromPointeeType) || 1139 Context.isObjCClassStructType(ToPointeeType)) 1140 return false; 1141 1142 if (FromPointeeType->isRecordType() && 1143 ToPointeeType->isRecordType()) { 1144 // We must have a derived-to-base conversion. Check an 1145 // ambiguous or inaccessible conversion. 1146 return CheckDerivedToBaseConversion(FromPointeeType, ToPointeeType, 1147 From->getExprLoc(), 1148 From->getSourceRange()); 1149 } 1150 } 1151 1152 return false; 1153} 1154 1155/// IsMemberPointerConversion - Determines whether the conversion of the 1156/// expression From, which has the (possibly adjusted) type FromType, can be 1157/// converted to the type ToType via a member pointer conversion (C++ 4.11). 1158/// If so, returns true and places the converted type (that might differ from 1159/// ToType in its cv-qualifiers at some level) into ConvertedType. 1160bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType, 1161 QualType ToType, QualType &ConvertedType) 1162{ 1163 const MemberPointerType *ToTypePtr = ToType->getAsMemberPointerType(); 1164 if (!ToTypePtr) 1165 return false; 1166 1167 // A null pointer constant can be converted to a member pointer (C++ 4.11p1) 1168 if (From->isNullPointerConstant(Context)) { 1169 ConvertedType = ToType; 1170 return true; 1171 } 1172 1173 // Otherwise, both types have to be member pointers. 1174 const MemberPointerType *FromTypePtr = FromType->getAsMemberPointerType(); 1175 if (!FromTypePtr) 1176 return false; 1177 1178 // A pointer to member of B can be converted to a pointer to member of D, 1179 // where D is derived from B (C++ 4.11p2). 1180 QualType FromClass(FromTypePtr->getClass(), 0); 1181 QualType ToClass(ToTypePtr->getClass(), 0); 1182 // FIXME: What happens when these are dependent? Is this function even called? 1183 1184 if (IsDerivedFrom(ToClass, FromClass)) { 1185 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(), 1186 ToClass.getTypePtr()); 1187 return true; 1188 } 1189 1190 return false; 1191} 1192 1193/// CheckMemberPointerConversion - Check the member pointer conversion from the 1194/// expression From to the type ToType. This routine checks for ambiguous or 1195/// virtual (FIXME: or inaccessible) base-to-derived member pointer conversions 1196/// for which IsMemberPointerConversion has already returned true. It returns 1197/// true and produces a diagnostic if there was an error, or returns false 1198/// otherwise. 1199bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType) { 1200 QualType FromType = From->getType(); 1201 const MemberPointerType *FromPtrType = FromType->getAsMemberPointerType(); 1202 if (!FromPtrType) 1203 return false; 1204 1205 const MemberPointerType *ToPtrType = ToType->getAsMemberPointerType(); 1206 assert(ToPtrType && "No member pointer cast has a target type " 1207 "that is not a member pointer."); 1208 1209 QualType FromClass = QualType(FromPtrType->getClass(), 0); 1210 QualType ToClass = QualType(ToPtrType->getClass(), 0); 1211 1212 // FIXME: What about dependent types? 1213 assert(FromClass->isRecordType() && "Pointer into non-class."); 1214 assert(ToClass->isRecordType() && "Pointer into non-class."); 1215 1216 BasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/false, 1217 /*DetectVirtual=*/true); 1218 bool DerivationOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1219 assert(DerivationOkay && 1220 "Should not have been called if derivation isn't OK."); 1221 (void)DerivationOkay; 1222 1223 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass). 1224 getUnqualifiedType())) { 1225 // Derivation is ambiguous. Redo the check to find the exact paths. 1226 Paths.clear(); 1227 Paths.setRecordingPaths(true); 1228 bool StillOkay = IsDerivedFrom(ToClass, FromClass, Paths); 1229 assert(StillOkay && "Derivation changed due to quantum fluctuation."); 1230 (void)StillOkay; 1231 1232 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths); 1233 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv) 1234 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange(); 1235 return true; 1236 } 1237 1238 if (const RecordType *VBase = Paths.getDetectedVirtual()) { 1239 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual) 1240 << FromClass << ToClass << QualType(VBase, 0) 1241 << From->getSourceRange(); 1242 return true; 1243 } 1244 1245 return false; 1246} 1247 1248/// IsQualificationConversion - Determines whether the conversion from 1249/// an rvalue of type FromType to ToType is a qualification conversion 1250/// (C++ 4.4). 1251bool 1252Sema::IsQualificationConversion(QualType FromType, QualType ToType) 1253{ 1254 FromType = Context.getCanonicalType(FromType); 1255 ToType = Context.getCanonicalType(ToType); 1256 1257 // If FromType and ToType are the same type, this is not a 1258 // qualification conversion. 1259 if (FromType == ToType) 1260 return false; 1261 1262 // (C++ 4.4p4): 1263 // A conversion can add cv-qualifiers at levels other than the first 1264 // in multi-level pointers, subject to the following rules: [...] 1265 bool PreviousToQualsIncludeConst = true; 1266 bool UnwrappedAnyPointer = false; 1267 while (UnwrapSimilarPointerTypes(FromType, ToType)) { 1268 // Within each iteration of the loop, we check the qualifiers to 1269 // determine if this still looks like a qualification 1270 // conversion. Then, if all is well, we unwrap one more level of 1271 // pointers or pointers-to-members and do it all again 1272 // until there are no more pointers or pointers-to-members left to 1273 // unwrap. 1274 UnwrappedAnyPointer = true; 1275 1276 // -- for every j > 0, if const is in cv 1,j then const is in cv 1277 // 2,j, and similarly for volatile. 1278 if (!ToType.isAtLeastAsQualifiedAs(FromType)) 1279 return false; 1280 1281 // -- if the cv 1,j and cv 2,j are different, then const is in 1282 // every cv for 0 < k < j. 1283 if (FromType.getCVRQualifiers() != ToType.getCVRQualifiers() 1284 && !PreviousToQualsIncludeConst) 1285 return false; 1286 1287 // Keep track of whether all prior cv-qualifiers in the "to" type 1288 // include const. 1289 PreviousToQualsIncludeConst 1290 = PreviousToQualsIncludeConst && ToType.isConstQualified(); 1291 } 1292 1293 // We are left with FromType and ToType being the pointee types 1294 // after unwrapping the original FromType and ToType the same number 1295 // of types. If we unwrapped any pointers, and if FromType and 1296 // ToType have the same unqualified type (since we checked 1297 // qualifiers above), then this is a qualification conversion. 1298 return UnwrappedAnyPointer && 1299 FromType.getUnqualifiedType() == ToType.getUnqualifiedType(); 1300} 1301 1302/// Determines whether there is a user-defined conversion sequence 1303/// (C++ [over.ics.user]) that converts expression From to the type 1304/// ToType. If such a conversion exists, User will contain the 1305/// user-defined conversion sequence that performs such a conversion 1306/// and this routine will return true. Otherwise, this routine returns 1307/// false and User is unspecified. 1308/// 1309/// \param AllowConversionFunctions true if the conversion should 1310/// consider conversion functions at all. If false, only constructors 1311/// will be considered. 1312/// 1313/// \param AllowExplicit true if the conversion should consider C++0x 1314/// "explicit" conversion functions as well as non-explicit conversion 1315/// functions (C++0x [class.conv.fct]p2). 1316bool Sema::IsUserDefinedConversion(Expr *From, QualType ToType, 1317 UserDefinedConversionSequence& User, 1318 bool AllowConversionFunctions, 1319 bool AllowExplicit) 1320{ 1321 OverloadCandidateSet CandidateSet; 1322 if (const RecordType *ToRecordType = ToType->getAsRecordType()) { 1323 if (CXXRecordDecl *ToRecordDecl 1324 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) { 1325 // C++ [over.match.ctor]p1: 1326 // When objects of class type are direct-initialized (8.5), or 1327 // copy-initialized from an expression of the same or a 1328 // derived class type (8.5), overload resolution selects the 1329 // constructor. [...] For copy-initialization, the candidate 1330 // functions are all the converting constructors (12.3.1) of 1331 // that class. The argument list is the expression-list within 1332 // the parentheses of the initializer. 1333 DeclarationName ConstructorName 1334 = Context.DeclarationNames.getCXXConstructorName( 1335 Context.getCanonicalType(ToType).getUnqualifiedType()); 1336 DeclContext::lookup_iterator Con, ConEnd; 1337 for (llvm::tie(Con, ConEnd) 1338 = ToRecordDecl->lookup(Context, ConstructorName); 1339 Con != ConEnd; ++Con) { 1340 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(*Con); 1341 if (Constructor->isConvertingConstructor()) 1342 AddOverloadCandidate(Constructor, &From, 1, CandidateSet, 1343 /*SuppressUserConversions=*/true); 1344 } 1345 } 1346 } 1347 1348 if (!AllowConversionFunctions) { 1349 // Don't allow any conversion functions to enter the overload set. 1350 } else if (const RecordType *FromRecordType 1351 = From->getType()->getAsRecordType()) { 1352 if (CXXRecordDecl *FromRecordDecl 1353 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) { 1354 // Add all of the conversion functions as candidates. 1355 // FIXME: Look for conversions in base classes! 1356 OverloadedFunctionDecl *Conversions 1357 = FromRecordDecl->getConversionFunctions(); 1358 for (OverloadedFunctionDecl::function_iterator Func 1359 = Conversions->function_begin(); 1360 Func != Conversions->function_end(); ++Func) { 1361 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 1362 if (AllowExplicit || !Conv->isExplicit()) 1363 AddConversionCandidate(Conv, From, ToType, CandidateSet); 1364 } 1365 } 1366 } 1367 1368 OverloadCandidateSet::iterator Best; 1369 switch (BestViableFunction(CandidateSet, Best)) { 1370 case OR_Success: 1371 // Record the standard conversion we used and the conversion function. 1372 if (CXXConstructorDecl *Constructor 1373 = dyn_cast<CXXConstructorDecl>(Best->Function)) { 1374 // C++ [over.ics.user]p1: 1375 // If the user-defined conversion is specified by a 1376 // constructor (12.3.1), the initial standard conversion 1377 // sequence converts the source type to the type required by 1378 // the argument of the constructor. 1379 // 1380 // FIXME: What about ellipsis conversions? 1381 QualType ThisType = Constructor->getThisType(Context); 1382 User.Before = Best->Conversions[0].Standard; 1383 User.ConversionFunction = Constructor; 1384 User.After.setAsIdentityConversion(); 1385 User.After.FromTypePtr 1386 = ThisType->getAsPointerType()->getPointeeType().getAsOpaquePtr(); 1387 User.After.ToTypePtr = ToType.getAsOpaquePtr(); 1388 return true; 1389 } else if (CXXConversionDecl *Conversion 1390 = dyn_cast<CXXConversionDecl>(Best->Function)) { 1391 // C++ [over.ics.user]p1: 1392 // 1393 // [...] If the user-defined conversion is specified by a 1394 // conversion function (12.3.2), the initial standard 1395 // conversion sequence converts the source type to the 1396 // implicit object parameter of the conversion function. 1397 User.Before = Best->Conversions[0].Standard; 1398 User.ConversionFunction = Conversion; 1399 1400 // C++ [over.ics.user]p2: 1401 // The second standard conversion sequence converts the 1402 // result of the user-defined conversion to the target type 1403 // for the sequence. Since an implicit conversion sequence 1404 // is an initialization, the special rules for 1405 // initialization by user-defined conversion apply when 1406 // selecting the best user-defined conversion for a 1407 // user-defined conversion sequence (see 13.3.3 and 1408 // 13.3.3.1). 1409 User.After = Best->FinalConversion; 1410 return true; 1411 } else { 1412 assert(false && "Not a constructor or conversion function?"); 1413 return false; 1414 } 1415 1416 case OR_No_Viable_Function: 1417 case OR_Deleted: 1418 // No conversion here! We're done. 1419 return false; 1420 1421 case OR_Ambiguous: 1422 // FIXME: See C++ [over.best.ics]p10 for the handling of 1423 // ambiguous conversion sequences. 1424 return false; 1425 } 1426 1427 return false; 1428} 1429 1430/// CompareImplicitConversionSequences - Compare two implicit 1431/// conversion sequences to determine whether one is better than the 1432/// other or if they are indistinguishable (C++ 13.3.3.2). 1433ImplicitConversionSequence::CompareKind 1434Sema::CompareImplicitConversionSequences(const ImplicitConversionSequence& ICS1, 1435 const ImplicitConversionSequence& ICS2) 1436{ 1437 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit 1438 // conversion sequences (as defined in 13.3.3.1) 1439 // -- a standard conversion sequence (13.3.3.1.1) is a better 1440 // conversion sequence than a user-defined conversion sequence or 1441 // an ellipsis conversion sequence, and 1442 // -- a user-defined conversion sequence (13.3.3.1.2) is a better 1443 // conversion sequence than an ellipsis conversion sequence 1444 // (13.3.3.1.3). 1445 // 1446 if (ICS1.ConversionKind < ICS2.ConversionKind) 1447 return ImplicitConversionSequence::Better; 1448 else if (ICS2.ConversionKind < ICS1.ConversionKind) 1449 return ImplicitConversionSequence::Worse; 1450 1451 // Two implicit conversion sequences of the same form are 1452 // indistinguishable conversion sequences unless one of the 1453 // following rules apply: (C++ 13.3.3.2p3): 1454 if (ICS1.ConversionKind == ImplicitConversionSequence::StandardConversion) 1455 return CompareStandardConversionSequences(ICS1.Standard, ICS2.Standard); 1456 else if (ICS1.ConversionKind == 1457 ImplicitConversionSequence::UserDefinedConversion) { 1458 // User-defined conversion sequence U1 is a better conversion 1459 // sequence than another user-defined conversion sequence U2 if 1460 // they contain the same user-defined conversion function or 1461 // constructor and if the second standard conversion sequence of 1462 // U1 is better than the second standard conversion sequence of 1463 // U2 (C++ 13.3.3.2p3). 1464 if (ICS1.UserDefined.ConversionFunction == 1465 ICS2.UserDefined.ConversionFunction) 1466 return CompareStandardConversionSequences(ICS1.UserDefined.After, 1467 ICS2.UserDefined.After); 1468 } 1469 1470 return ImplicitConversionSequence::Indistinguishable; 1471} 1472 1473/// CompareStandardConversionSequences - Compare two standard 1474/// conversion sequences to determine whether one is better than the 1475/// other or if they are indistinguishable (C++ 13.3.3.2p3). 1476ImplicitConversionSequence::CompareKind 1477Sema::CompareStandardConversionSequences(const StandardConversionSequence& SCS1, 1478 const StandardConversionSequence& SCS2) 1479{ 1480 // Standard conversion sequence S1 is a better conversion sequence 1481 // than standard conversion sequence S2 if (C++ 13.3.3.2p3): 1482 1483 // -- S1 is a proper subsequence of S2 (comparing the conversion 1484 // sequences in the canonical form defined by 13.3.3.1.1, 1485 // excluding any Lvalue Transformation; the identity conversion 1486 // sequence is considered to be a subsequence of any 1487 // non-identity conversion sequence) or, if not that, 1488 if (SCS1.Second == SCS2.Second && SCS1.Third == SCS2.Third) 1489 // Neither is a proper subsequence of the other. Do nothing. 1490 ; 1491 else if ((SCS1.Second == ICK_Identity && SCS1.Third == SCS2.Third) || 1492 (SCS1.Third == ICK_Identity && SCS1.Second == SCS2.Second) || 1493 (SCS1.Second == ICK_Identity && 1494 SCS1.Third == ICK_Identity)) 1495 // SCS1 is a proper subsequence of SCS2. 1496 return ImplicitConversionSequence::Better; 1497 else if ((SCS2.Second == ICK_Identity && SCS2.Third == SCS1.Third) || 1498 (SCS2.Third == ICK_Identity && SCS2.Second == SCS1.Second) || 1499 (SCS2.Second == ICK_Identity && 1500 SCS2.Third == ICK_Identity)) 1501 // SCS2 is a proper subsequence of SCS1. 1502 return ImplicitConversionSequence::Worse; 1503 1504 // -- the rank of S1 is better than the rank of S2 (by the rules 1505 // defined below), or, if not that, 1506 ImplicitConversionRank Rank1 = SCS1.getRank(); 1507 ImplicitConversionRank Rank2 = SCS2.getRank(); 1508 if (Rank1 < Rank2) 1509 return ImplicitConversionSequence::Better; 1510 else if (Rank2 < Rank1) 1511 return ImplicitConversionSequence::Worse; 1512 1513 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank 1514 // are indistinguishable unless one of the following rules 1515 // applies: 1516 1517 // A conversion that is not a conversion of a pointer, or 1518 // pointer to member, to bool is better than another conversion 1519 // that is such a conversion. 1520 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool()) 1521 return SCS2.isPointerConversionToBool() 1522 ? ImplicitConversionSequence::Better 1523 : ImplicitConversionSequence::Worse; 1524 1525 // C++ [over.ics.rank]p4b2: 1526 // 1527 // If class B is derived directly or indirectly from class A, 1528 // conversion of B* to A* is better than conversion of B* to 1529 // void*, and conversion of A* to void* is better than conversion 1530 // of B* to void*. 1531 bool SCS1ConvertsToVoid 1532 = SCS1.isPointerConversionToVoidPointer(Context); 1533 bool SCS2ConvertsToVoid 1534 = SCS2.isPointerConversionToVoidPointer(Context); 1535 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) { 1536 // Exactly one of the conversion sequences is a conversion to 1537 // a void pointer; it's the worse conversion. 1538 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better 1539 : ImplicitConversionSequence::Worse; 1540 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) { 1541 // Neither conversion sequence converts to a void pointer; compare 1542 // their derived-to-base conversions. 1543 if (ImplicitConversionSequence::CompareKind DerivedCK 1544 = CompareDerivedToBaseConversions(SCS1, SCS2)) 1545 return DerivedCK; 1546 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid) { 1547 // Both conversion sequences are conversions to void 1548 // pointers. Compare the source types to determine if there's an 1549 // inheritance relationship in their sources. 1550 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1551 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1552 1553 // Adjust the types we're converting from via the array-to-pointer 1554 // conversion, if we need to. 1555 if (SCS1.First == ICK_Array_To_Pointer) 1556 FromType1 = Context.getArrayDecayedType(FromType1); 1557 if (SCS2.First == ICK_Array_To_Pointer) 1558 FromType2 = Context.getArrayDecayedType(FromType2); 1559 1560 QualType FromPointee1 1561 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1562 QualType FromPointee2 1563 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1564 1565 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1566 return ImplicitConversionSequence::Better; 1567 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1568 return ImplicitConversionSequence::Worse; 1569 1570 // Objective-C++: If one interface is more specific than the 1571 // other, it is the better one. 1572 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1573 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1574 if (FromIface1 && FromIface1) { 1575 if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1576 return ImplicitConversionSequence::Better; 1577 else if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1578 return ImplicitConversionSequence::Worse; 1579 } 1580 } 1581 1582 // Compare based on qualification conversions (C++ 13.3.3.2p3, 1583 // bullet 3). 1584 if (ImplicitConversionSequence::CompareKind QualCK 1585 = CompareQualificationConversions(SCS1, SCS2)) 1586 return QualCK; 1587 1588 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) { 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 don't know if we're dealing with the implicit object parameter, 1595 // or if the member function in this case has a ref qualifier. 1596 // (Of course, we don't have ref qualifiers yet.) 1597 if (SCS1.RRefBinding != SCS2.RRefBinding) 1598 return SCS1.RRefBinding ? ImplicitConversionSequence::Better 1599 : ImplicitConversionSequence::Worse; 1600 1601 // C++ [over.ics.rank]p3b4: 1602 // -- S1 and S2 are reference bindings (8.5.3), and the types to 1603 // which the references refer are the same type except for 1604 // top-level cv-qualifiers, and the type to which the reference 1605 // initialized by S2 refers is more cv-qualified than the type 1606 // to which the reference initialized by S1 refers. 1607 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1608 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1609 T1 = Context.getCanonicalType(T1); 1610 T2 = Context.getCanonicalType(T2); 1611 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) { 1612 if (T2.isMoreQualifiedThan(T1)) 1613 return ImplicitConversionSequence::Better; 1614 else if (T1.isMoreQualifiedThan(T2)) 1615 return ImplicitConversionSequence::Worse; 1616 } 1617 } 1618 1619 return ImplicitConversionSequence::Indistinguishable; 1620} 1621 1622/// CompareQualificationConversions - Compares two standard conversion 1623/// sequences to determine whether they can be ranked based on their 1624/// qualification conversions (C++ 13.3.3.2p3 bullet 3). 1625ImplicitConversionSequence::CompareKind 1626Sema::CompareQualificationConversions(const StandardConversionSequence& SCS1, 1627 const StandardConversionSequence& SCS2) 1628{ 1629 // C++ 13.3.3.2p3: 1630 // -- S1 and S2 differ only in their qualification conversion and 1631 // yield similar types T1 and T2 (C++ 4.4), respectively, and the 1632 // cv-qualification signature of type T1 is a proper subset of 1633 // the cv-qualification signature of type T2, and S1 is not the 1634 // deprecated string literal array-to-pointer conversion (4.2). 1635 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second || 1636 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification) 1637 return ImplicitConversionSequence::Indistinguishable; 1638 1639 // FIXME: the example in the standard doesn't use a qualification 1640 // conversion (!) 1641 QualType T1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1642 QualType T2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1643 T1 = Context.getCanonicalType(T1); 1644 T2 = Context.getCanonicalType(T2); 1645 1646 // If the types are the same, we won't learn anything by unwrapped 1647 // them. 1648 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1649 return ImplicitConversionSequence::Indistinguishable; 1650 1651 ImplicitConversionSequence::CompareKind Result 1652 = ImplicitConversionSequence::Indistinguishable; 1653 while (UnwrapSimilarPointerTypes(T1, T2)) { 1654 // Within each iteration of the loop, we check the qualifiers to 1655 // determine if this still looks like a qualification 1656 // conversion. Then, if all is well, we unwrap one more level of 1657 // pointers or pointers-to-members and do it all again 1658 // until there are no more pointers or pointers-to-members left 1659 // to unwrap. This essentially mimics what 1660 // IsQualificationConversion does, but here we're checking for a 1661 // strict subset of qualifiers. 1662 if (T1.getCVRQualifiers() == T2.getCVRQualifiers()) 1663 // The qualifiers are the same, so this doesn't tell us anything 1664 // about how the sequences rank. 1665 ; 1666 else if (T2.isMoreQualifiedThan(T1)) { 1667 // T1 has fewer qualifiers, so it could be the better sequence. 1668 if (Result == ImplicitConversionSequence::Worse) 1669 // Neither has qualifiers that are a subset of the other's 1670 // qualifiers. 1671 return ImplicitConversionSequence::Indistinguishable; 1672 1673 Result = ImplicitConversionSequence::Better; 1674 } else if (T1.isMoreQualifiedThan(T2)) { 1675 // T2 has fewer qualifiers, so it could be the better sequence. 1676 if (Result == ImplicitConversionSequence::Better) 1677 // Neither has qualifiers that are a subset of the other's 1678 // qualifiers. 1679 return ImplicitConversionSequence::Indistinguishable; 1680 1681 Result = ImplicitConversionSequence::Worse; 1682 } else { 1683 // Qualifiers are disjoint. 1684 return ImplicitConversionSequence::Indistinguishable; 1685 } 1686 1687 // If the types after this point are equivalent, we're done. 1688 if (T1.getUnqualifiedType() == T2.getUnqualifiedType()) 1689 break; 1690 } 1691 1692 // Check that the winning standard conversion sequence isn't using 1693 // the deprecated string literal array to pointer conversion. 1694 switch (Result) { 1695 case ImplicitConversionSequence::Better: 1696 if (SCS1.Deprecated) 1697 Result = ImplicitConversionSequence::Indistinguishable; 1698 break; 1699 1700 case ImplicitConversionSequence::Indistinguishable: 1701 break; 1702 1703 case ImplicitConversionSequence::Worse: 1704 if (SCS2.Deprecated) 1705 Result = ImplicitConversionSequence::Indistinguishable; 1706 break; 1707 } 1708 1709 return Result; 1710} 1711 1712/// CompareDerivedToBaseConversions - Compares two standard conversion 1713/// sequences to determine whether they can be ranked based on their 1714/// various kinds of derived-to-base conversions (C++ 1715/// [over.ics.rank]p4b3). As part of these checks, we also look at 1716/// conversions between Objective-C interface types. 1717ImplicitConversionSequence::CompareKind 1718Sema::CompareDerivedToBaseConversions(const StandardConversionSequence& SCS1, 1719 const StandardConversionSequence& SCS2) { 1720 QualType FromType1 = QualType::getFromOpaquePtr(SCS1.FromTypePtr); 1721 QualType ToType1 = QualType::getFromOpaquePtr(SCS1.ToTypePtr); 1722 QualType FromType2 = QualType::getFromOpaquePtr(SCS2.FromTypePtr); 1723 QualType ToType2 = QualType::getFromOpaquePtr(SCS2.ToTypePtr); 1724 1725 // Adjust the types we're converting from via the array-to-pointer 1726 // conversion, if we need to. 1727 if (SCS1.First == ICK_Array_To_Pointer) 1728 FromType1 = Context.getArrayDecayedType(FromType1); 1729 if (SCS2.First == ICK_Array_To_Pointer) 1730 FromType2 = Context.getArrayDecayedType(FromType2); 1731 1732 // Canonicalize all of the types. 1733 FromType1 = Context.getCanonicalType(FromType1); 1734 ToType1 = Context.getCanonicalType(ToType1); 1735 FromType2 = Context.getCanonicalType(FromType2); 1736 ToType2 = Context.getCanonicalType(ToType2); 1737 1738 // C++ [over.ics.rank]p4b3: 1739 // 1740 // If class B is derived directly or indirectly from class A and 1741 // class C is derived directly or indirectly from B, 1742 // 1743 // For Objective-C, we let A, B, and C also be Objective-C 1744 // interfaces. 1745 1746 // Compare based on pointer conversions. 1747 if (SCS1.Second == ICK_Pointer_Conversion && 1748 SCS2.Second == ICK_Pointer_Conversion && 1749 /*FIXME: Remove if Objective-C id conversions get their own rank*/ 1750 FromType1->isPointerType() && FromType2->isPointerType() && 1751 ToType1->isPointerType() && ToType2->isPointerType()) { 1752 QualType FromPointee1 1753 = FromType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1754 QualType ToPointee1 1755 = ToType1->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1756 QualType FromPointee2 1757 = FromType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1758 QualType ToPointee2 1759 = ToType2->getAsPointerType()->getPointeeType().getUnqualifiedType(); 1760 1761 const ObjCInterfaceType* FromIface1 = FromPointee1->getAsObjCInterfaceType(); 1762 const ObjCInterfaceType* FromIface2 = FromPointee2->getAsObjCInterfaceType(); 1763 const ObjCInterfaceType* ToIface1 = ToPointee1->getAsObjCInterfaceType(); 1764 const ObjCInterfaceType* ToIface2 = ToPointee2->getAsObjCInterfaceType(); 1765 1766 // -- conversion of C* to B* is better than conversion of C* to A*, 1767 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) { 1768 if (IsDerivedFrom(ToPointee1, ToPointee2)) 1769 return ImplicitConversionSequence::Better; 1770 else if (IsDerivedFrom(ToPointee2, ToPointee1)) 1771 return ImplicitConversionSequence::Worse; 1772 1773 if (ToIface1 && ToIface2) { 1774 if (Context.canAssignObjCInterfaces(ToIface2, ToIface1)) 1775 return ImplicitConversionSequence::Better; 1776 else if (Context.canAssignObjCInterfaces(ToIface1, ToIface2)) 1777 return ImplicitConversionSequence::Worse; 1778 } 1779 } 1780 1781 // -- conversion of B* to A* is better than conversion of C* to A*, 1782 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) { 1783 if (IsDerivedFrom(FromPointee2, FromPointee1)) 1784 return ImplicitConversionSequence::Better; 1785 else if (IsDerivedFrom(FromPointee1, FromPointee2)) 1786 return ImplicitConversionSequence::Worse; 1787 1788 if (FromIface1 && FromIface2) { 1789 if (Context.canAssignObjCInterfaces(FromIface1, FromIface2)) 1790 return ImplicitConversionSequence::Better; 1791 else if (Context.canAssignObjCInterfaces(FromIface2, FromIface1)) 1792 return ImplicitConversionSequence::Worse; 1793 } 1794 } 1795 } 1796 1797 // Compare based on reference bindings. 1798 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding && 1799 SCS1.Second == ICK_Derived_To_Base) { 1800 // -- binding of an expression of type C to a reference of type 1801 // B& is better than binding an expression of type C to a 1802 // reference of type A&, 1803 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1804 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1805 if (IsDerivedFrom(ToType1, ToType2)) 1806 return ImplicitConversionSequence::Better; 1807 else if (IsDerivedFrom(ToType2, ToType1)) 1808 return ImplicitConversionSequence::Worse; 1809 } 1810 1811 // -- binding of an expression of type B to a reference of type 1812 // A& is better than binding an expression of type C to a 1813 // reference of type A&, 1814 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1815 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1816 if (IsDerivedFrom(FromType2, FromType1)) 1817 return ImplicitConversionSequence::Better; 1818 else if (IsDerivedFrom(FromType1, FromType2)) 1819 return ImplicitConversionSequence::Worse; 1820 } 1821 } 1822 1823 1824 // FIXME: conversion of A::* to B::* is better than conversion of 1825 // A::* to C::*, 1826 1827 // FIXME: conversion of B::* to C::* is better than conversion of 1828 // A::* to C::*, and 1829 1830 if (SCS1.CopyConstructor && SCS2.CopyConstructor && 1831 SCS1.Second == ICK_Derived_To_Base) { 1832 // -- conversion of C to B is better than conversion of C to A, 1833 if (FromType1.getUnqualifiedType() == FromType2.getUnqualifiedType() && 1834 ToType1.getUnqualifiedType() != ToType2.getUnqualifiedType()) { 1835 if (IsDerivedFrom(ToType1, ToType2)) 1836 return ImplicitConversionSequence::Better; 1837 else if (IsDerivedFrom(ToType2, ToType1)) 1838 return ImplicitConversionSequence::Worse; 1839 } 1840 1841 // -- conversion of B to A is better than conversion of C to A. 1842 if (FromType1.getUnqualifiedType() != FromType2.getUnqualifiedType() && 1843 ToType1.getUnqualifiedType() == ToType2.getUnqualifiedType()) { 1844 if (IsDerivedFrom(FromType2, FromType1)) 1845 return ImplicitConversionSequence::Better; 1846 else if (IsDerivedFrom(FromType1, FromType2)) 1847 return ImplicitConversionSequence::Worse; 1848 } 1849 } 1850 1851 return ImplicitConversionSequence::Indistinguishable; 1852} 1853 1854/// TryCopyInitialization - Try to copy-initialize a value of type 1855/// ToType from the expression From. Return the implicit conversion 1856/// sequence required to pass this argument, which may be a bad 1857/// conversion sequence (meaning that the argument cannot be passed to 1858/// a parameter of this type). If @p SuppressUserConversions, then we 1859/// do not permit any user-defined conversion sequences. 1860ImplicitConversionSequence 1861Sema::TryCopyInitialization(Expr *From, QualType ToType, 1862 bool SuppressUserConversions) { 1863 if (ToType->isReferenceType()) { 1864 ImplicitConversionSequence ICS; 1865 CheckReferenceInit(From, ToType, &ICS, SuppressUserConversions); 1866 return ICS; 1867 } else { 1868 return TryImplicitConversion(From, ToType, SuppressUserConversions); 1869 } 1870} 1871 1872/// PerformArgumentPassing - Pass the argument Arg into a parameter of 1873/// type ToType. Returns true (and emits a diagnostic) if there was 1874/// an error, returns false if the initialization succeeded. 1875bool Sema::PerformCopyInitialization(Expr *&From, QualType ToType, 1876 const char* Flavor) { 1877 if (!getLangOptions().CPlusPlus) { 1878 // In C, argument passing is the same as performing an assignment. 1879 QualType FromType = From->getType(); 1880 AssignConvertType ConvTy = 1881 CheckSingleAssignmentConstraints(ToType, From); 1882 1883 return DiagnoseAssignmentResult(ConvTy, From->getLocStart(), ToType, 1884 FromType, From, Flavor); 1885 } 1886 1887 if (ToType->isReferenceType()) 1888 return CheckReferenceInit(From, ToType); 1889 1890 if (!PerformImplicitConversion(From, ToType, Flavor)) 1891 return false; 1892 1893 return Diag(From->getSourceRange().getBegin(), 1894 diag::err_typecheck_convert_incompatible) 1895 << ToType << From->getType() << Flavor << From->getSourceRange(); 1896} 1897 1898/// TryObjectArgumentInitialization - Try to initialize the object 1899/// parameter of the given member function (@c Method) from the 1900/// expression @p From. 1901ImplicitConversionSequence 1902Sema::TryObjectArgumentInitialization(Expr *From, CXXMethodDecl *Method) { 1903 QualType ClassType = Context.getTypeDeclType(Method->getParent()); 1904 unsigned MethodQuals = Method->getTypeQualifiers(); 1905 QualType ImplicitParamType = ClassType.getQualifiedType(MethodQuals); 1906 1907 // Set up the conversion sequence as a "bad" conversion, to allow us 1908 // to exit early. 1909 ImplicitConversionSequence ICS; 1910 ICS.Standard.setAsIdentityConversion(); 1911 ICS.ConversionKind = ImplicitConversionSequence::BadConversion; 1912 1913 // We need to have an object of class type. 1914 QualType FromType = From->getType(); 1915 if (!FromType->isRecordType()) 1916 return ICS; 1917 1918 // The implicit object parmeter is has the type "reference to cv X", 1919 // where X is the class of which the function is a member 1920 // (C++ [over.match.funcs]p4). However, when finding an implicit 1921 // conversion sequence for the argument, we are not allowed to 1922 // create temporaries or perform user-defined conversions 1923 // (C++ [over.match.funcs]p5). We perform a simplified version of 1924 // reference binding here, that allows class rvalues to bind to 1925 // non-constant references. 1926 1927 // First check the qualifiers. We don't care about lvalue-vs-rvalue 1928 // with the implicit object parameter (C++ [over.match.funcs]p5). 1929 QualType FromTypeCanon = Context.getCanonicalType(FromType); 1930 if (ImplicitParamType.getCVRQualifiers() != FromType.getCVRQualifiers() && 1931 !ImplicitParamType.isAtLeastAsQualifiedAs(FromType)) 1932 return ICS; 1933 1934 // Check that we have either the same type or a derived type. It 1935 // affects the conversion rank. 1936 QualType ClassTypeCanon = Context.getCanonicalType(ClassType); 1937 if (ClassTypeCanon == FromTypeCanon.getUnqualifiedType()) 1938 ICS.Standard.Second = ICK_Identity; 1939 else if (IsDerivedFrom(FromType, ClassType)) 1940 ICS.Standard.Second = ICK_Derived_To_Base; 1941 else 1942 return ICS; 1943 1944 // Success. Mark this as a reference binding. 1945 ICS.ConversionKind = ImplicitConversionSequence::StandardConversion; 1946 ICS.Standard.FromTypePtr = FromType.getAsOpaquePtr(); 1947 ICS.Standard.ToTypePtr = ImplicitParamType.getAsOpaquePtr(); 1948 ICS.Standard.ReferenceBinding = true; 1949 ICS.Standard.DirectBinding = true; 1950 ICS.Standard.RRefBinding = false; 1951 return ICS; 1952} 1953 1954/// PerformObjectArgumentInitialization - Perform initialization of 1955/// the implicit object parameter for the given Method with the given 1956/// expression. 1957bool 1958Sema::PerformObjectArgumentInitialization(Expr *&From, CXXMethodDecl *Method) { 1959 QualType ImplicitParamType 1960 = Method->getThisType(Context)->getAsPointerType()->getPointeeType(); 1961 ImplicitConversionSequence ICS 1962 = TryObjectArgumentInitialization(From, Method); 1963 if (ICS.ConversionKind == ImplicitConversionSequence::BadConversion) 1964 return Diag(From->getSourceRange().getBegin(), 1965 diag::err_implicit_object_parameter_init) 1966 << ImplicitParamType << From->getType() << From->getSourceRange(); 1967 1968 if (ICS.Standard.Second == ICK_Derived_To_Base && 1969 CheckDerivedToBaseConversion(From->getType(), ImplicitParamType, 1970 From->getSourceRange().getBegin(), 1971 From->getSourceRange())) 1972 return true; 1973 1974 ImpCastExprToType(From, ImplicitParamType, /*isLvalue=*/true); 1975 return false; 1976} 1977 1978/// TryContextuallyConvertToBool - Attempt to contextually convert the 1979/// expression From to bool (C++0x [conv]p3). 1980ImplicitConversionSequence Sema::TryContextuallyConvertToBool(Expr *From) { 1981 return TryImplicitConversion(From, Context.BoolTy, false, true); 1982} 1983 1984/// PerformContextuallyConvertToBool - Perform a contextual conversion 1985/// of the expression From to bool (C++0x [conv]p3). 1986bool Sema::PerformContextuallyConvertToBool(Expr *&From) { 1987 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(From); 1988 if (!PerformImplicitConversion(From, Context.BoolTy, ICS, "converting")) 1989 return false; 1990 1991 return Diag(From->getSourceRange().getBegin(), 1992 diag::err_typecheck_bool_condition) 1993 << From->getType() << From->getSourceRange(); 1994} 1995 1996/// AddOverloadCandidate - Adds the given function to the set of 1997/// candidate functions, using the given function call arguments. If 1998/// @p SuppressUserConversions, then don't allow user-defined 1999/// conversions via constructors or conversion operators. 2000void 2001Sema::AddOverloadCandidate(FunctionDecl *Function, 2002 Expr **Args, unsigned NumArgs, 2003 OverloadCandidateSet& CandidateSet, 2004 bool SuppressUserConversions) 2005{ 2006 const FunctionProtoType* Proto 2007 = dyn_cast<FunctionProtoType>(Function->getType()->getAsFunctionType()); 2008 assert(Proto && "Functions without a prototype cannot be overloaded"); 2009 assert(!isa<CXXConversionDecl>(Function) && 2010 "Use AddConversionCandidate for conversion functions"); 2011 2012 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) { 2013 // If we get here, it's because we're calling a member function 2014 // that is named without a member access expression (e.g., 2015 // "this->f") that was either written explicitly or created 2016 // implicitly. This can happen with a qualified call to a member 2017 // function, e.g., X::f(). We use a NULL object as the implied 2018 // object argument (C++ [over.call.func]p3). 2019 AddMethodCandidate(Method, 0, Args, NumArgs, CandidateSet, 2020 SuppressUserConversions); 2021 return; 2022 } 2023 2024 2025 // Add this candidate 2026 CandidateSet.push_back(OverloadCandidate()); 2027 OverloadCandidate& Candidate = CandidateSet.back(); 2028 Candidate.Function = Function; 2029 Candidate.Viable = true; 2030 Candidate.IsSurrogate = false; 2031 Candidate.IgnoreObjectArgument = false; 2032 2033 unsigned NumArgsInProto = Proto->getNumArgs(); 2034 2035 // (C++ 13.3.2p2): A candidate function having fewer than m 2036 // parameters is viable only if it has an ellipsis in its parameter 2037 // list (8.3.5). 2038 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2039 Candidate.Viable = false; 2040 return; 2041 } 2042 2043 // (C++ 13.3.2p2): A candidate function having more than m parameters 2044 // is viable only if the (m+1)st parameter has a default argument 2045 // (8.3.6). For the purposes of overload resolution, the 2046 // parameter list is truncated on the right, so that there are 2047 // exactly m parameters. 2048 unsigned MinRequiredArgs = Function->getMinRequiredArguments(); 2049 if (NumArgs < MinRequiredArgs) { 2050 // Not enough arguments. 2051 Candidate.Viable = false; 2052 return; 2053 } 2054 2055 // Determine the implicit conversion sequences for each of the 2056 // arguments. 2057 Candidate.Conversions.resize(NumArgs); 2058 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2059 if (ArgIdx < NumArgsInProto) { 2060 // (C++ 13.3.2p3): for F to be a viable function, there shall 2061 // exist for each argument an implicit conversion sequence 2062 // (13.3.3.1) that converts that argument to the corresponding 2063 // parameter of F. 2064 QualType ParamType = Proto->getArgType(ArgIdx); 2065 Candidate.Conversions[ArgIdx] 2066 = TryCopyInitialization(Args[ArgIdx], ParamType, 2067 SuppressUserConversions); 2068 if (Candidate.Conversions[ArgIdx].ConversionKind 2069 == ImplicitConversionSequence::BadConversion) { 2070 Candidate.Viable = false; 2071 break; 2072 } 2073 } else { 2074 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2075 // argument for which there is no corresponding parameter is 2076 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2077 Candidate.Conversions[ArgIdx].ConversionKind 2078 = ImplicitConversionSequence::EllipsisConversion; 2079 } 2080 } 2081} 2082 2083/// \brief Add all of the function declarations in the given function set to 2084/// the overload canddiate set. 2085void Sema::AddFunctionCandidates(const FunctionSet &Functions, 2086 Expr **Args, unsigned NumArgs, 2087 OverloadCandidateSet& CandidateSet, 2088 bool SuppressUserConversions) { 2089 for (FunctionSet::const_iterator F = Functions.begin(), 2090 FEnd = Functions.end(); 2091 F != FEnd; ++F) 2092 AddOverloadCandidate(*F, Args, NumArgs, CandidateSet, 2093 SuppressUserConversions); 2094} 2095 2096/// AddMethodCandidate - Adds the given C++ member function to the set 2097/// of candidate functions, using the given function call arguments 2098/// and the object argument (@c Object). For example, in a call 2099/// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain 2100/// both @c a1 and @c a2. If @p SuppressUserConversions, then don't 2101/// allow user-defined conversions via constructors or conversion 2102/// operators. 2103void 2104Sema::AddMethodCandidate(CXXMethodDecl *Method, Expr *Object, 2105 Expr **Args, unsigned NumArgs, 2106 OverloadCandidateSet& CandidateSet, 2107 bool SuppressUserConversions) 2108{ 2109 const FunctionProtoType* Proto 2110 = dyn_cast<FunctionProtoType>(Method->getType()->getAsFunctionType()); 2111 assert(Proto && "Methods without a prototype cannot be overloaded"); 2112 assert(!isa<CXXConversionDecl>(Method) && 2113 "Use AddConversionCandidate for conversion functions"); 2114 2115 // Add this candidate 2116 CandidateSet.push_back(OverloadCandidate()); 2117 OverloadCandidate& Candidate = CandidateSet.back(); 2118 Candidate.Function = Method; 2119 Candidate.IsSurrogate = false; 2120 Candidate.IgnoreObjectArgument = false; 2121 2122 unsigned NumArgsInProto = Proto->getNumArgs(); 2123 2124 // (C++ 13.3.2p2): A candidate function having fewer than m 2125 // parameters is viable only if it has an ellipsis in its parameter 2126 // list (8.3.5). 2127 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2128 Candidate.Viable = false; 2129 return; 2130 } 2131 2132 // (C++ 13.3.2p2): A candidate function having more than m parameters 2133 // is viable only if the (m+1)st parameter has a default argument 2134 // (8.3.6). For the purposes of overload resolution, the 2135 // parameter list is truncated on the right, so that there are 2136 // exactly m parameters. 2137 unsigned MinRequiredArgs = Method->getMinRequiredArguments(); 2138 if (NumArgs < MinRequiredArgs) { 2139 // Not enough arguments. 2140 Candidate.Viable = false; 2141 return; 2142 } 2143 2144 Candidate.Viable = true; 2145 Candidate.Conversions.resize(NumArgs + 1); 2146 2147 if (Method->isStatic() || !Object) 2148 // The implicit object argument is ignored. 2149 Candidate.IgnoreObjectArgument = true; 2150 else { 2151 // Determine the implicit conversion sequence for the object 2152 // parameter. 2153 Candidate.Conversions[0] = TryObjectArgumentInitialization(Object, Method); 2154 if (Candidate.Conversions[0].ConversionKind 2155 == ImplicitConversionSequence::BadConversion) { 2156 Candidate.Viable = false; 2157 return; 2158 } 2159 } 2160 2161 // Determine the implicit conversion sequences for each of the 2162 // arguments. 2163 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2164 if (ArgIdx < NumArgsInProto) { 2165 // (C++ 13.3.2p3): for F to be a viable function, there shall 2166 // exist for each argument an implicit conversion sequence 2167 // (13.3.3.1) that converts that argument to the corresponding 2168 // parameter of F. 2169 QualType ParamType = Proto->getArgType(ArgIdx); 2170 Candidate.Conversions[ArgIdx + 1] 2171 = TryCopyInitialization(Args[ArgIdx], ParamType, 2172 SuppressUserConversions); 2173 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2174 == ImplicitConversionSequence::BadConversion) { 2175 Candidate.Viable = false; 2176 break; 2177 } 2178 } else { 2179 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2180 // argument for which there is no corresponding parameter is 2181 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2182 Candidate.Conversions[ArgIdx + 1].ConversionKind 2183 = ImplicitConversionSequence::EllipsisConversion; 2184 } 2185 } 2186} 2187 2188/// AddConversionCandidate - Add a C++ conversion function as a 2189/// candidate in the candidate set (C++ [over.match.conv], 2190/// C++ [over.match.copy]). From is the expression we're converting from, 2191/// and ToType is the type that we're eventually trying to convert to 2192/// (which may or may not be the same type as the type that the 2193/// conversion function produces). 2194void 2195Sema::AddConversionCandidate(CXXConversionDecl *Conversion, 2196 Expr *From, QualType ToType, 2197 OverloadCandidateSet& CandidateSet) { 2198 // Add this candidate 2199 CandidateSet.push_back(OverloadCandidate()); 2200 OverloadCandidate& Candidate = CandidateSet.back(); 2201 Candidate.Function = Conversion; 2202 Candidate.IsSurrogate = false; 2203 Candidate.IgnoreObjectArgument = false; 2204 Candidate.FinalConversion.setAsIdentityConversion(); 2205 Candidate.FinalConversion.FromTypePtr 2206 = Conversion->getConversionType().getAsOpaquePtr(); 2207 Candidate.FinalConversion.ToTypePtr = ToType.getAsOpaquePtr(); 2208 2209 // Determine the implicit conversion sequence for the implicit 2210 // object parameter. 2211 Candidate.Viable = true; 2212 Candidate.Conversions.resize(1); 2213 Candidate.Conversions[0] = TryObjectArgumentInitialization(From, Conversion); 2214 2215 if (Candidate.Conversions[0].ConversionKind 2216 == ImplicitConversionSequence::BadConversion) { 2217 Candidate.Viable = false; 2218 return; 2219 } 2220 2221 // To determine what the conversion from the result of calling the 2222 // conversion function to the type we're eventually trying to 2223 // convert to (ToType), we need to synthesize a call to the 2224 // conversion function and attempt copy initialization from it. This 2225 // makes sure that we get the right semantics with respect to 2226 // lvalues/rvalues and the type. Fortunately, we can allocate this 2227 // call on the stack and we don't need its arguments to be 2228 // well-formed. 2229 DeclRefExpr ConversionRef(Conversion, Conversion->getType(), 2230 SourceLocation()); 2231 ImplicitCastExpr ConversionFn(Context.getPointerType(Conversion->getType()), 2232 &ConversionRef, false); 2233 2234 // Note that it is safe to allocate CallExpr on the stack here because 2235 // there are 0 arguments (i.e., nothing is allocated using ASTContext's 2236 // allocator). 2237 CallExpr Call(Context, &ConversionFn, 0, 0, 2238 Conversion->getConversionType().getNonReferenceType(), 2239 SourceLocation()); 2240 ImplicitConversionSequence ICS = TryCopyInitialization(&Call, ToType, true); 2241 switch (ICS.ConversionKind) { 2242 case ImplicitConversionSequence::StandardConversion: 2243 Candidate.FinalConversion = ICS.Standard; 2244 break; 2245 2246 case ImplicitConversionSequence::BadConversion: 2247 Candidate.Viable = false; 2248 break; 2249 2250 default: 2251 assert(false && 2252 "Can only end up with a standard conversion sequence or failure"); 2253 } 2254} 2255 2256/// AddSurrogateCandidate - Adds a "surrogate" candidate function that 2257/// converts the given @c Object to a function pointer via the 2258/// conversion function @c Conversion, and then attempts to call it 2259/// with the given arguments (C++ [over.call.object]p2-4). Proto is 2260/// the type of function that we'll eventually be calling. 2261void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion, 2262 const FunctionProtoType *Proto, 2263 Expr *Object, Expr **Args, unsigned NumArgs, 2264 OverloadCandidateSet& CandidateSet) { 2265 CandidateSet.push_back(OverloadCandidate()); 2266 OverloadCandidate& Candidate = CandidateSet.back(); 2267 Candidate.Function = 0; 2268 Candidate.Surrogate = Conversion; 2269 Candidate.Viable = true; 2270 Candidate.IsSurrogate = true; 2271 Candidate.IgnoreObjectArgument = false; 2272 Candidate.Conversions.resize(NumArgs + 1); 2273 2274 // Determine the implicit conversion sequence for the implicit 2275 // object parameter. 2276 ImplicitConversionSequence ObjectInit 2277 = TryObjectArgumentInitialization(Object, Conversion); 2278 if (ObjectInit.ConversionKind == ImplicitConversionSequence::BadConversion) { 2279 Candidate.Viable = false; 2280 return; 2281 } 2282 2283 // The first conversion is actually a user-defined conversion whose 2284 // first conversion is ObjectInit's standard conversion (which is 2285 // effectively a reference binding). Record it as such. 2286 Candidate.Conversions[0].ConversionKind 2287 = ImplicitConversionSequence::UserDefinedConversion; 2288 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard; 2289 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion; 2290 Candidate.Conversions[0].UserDefined.After 2291 = Candidate.Conversions[0].UserDefined.Before; 2292 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion(); 2293 2294 // Find the 2295 unsigned NumArgsInProto = Proto->getNumArgs(); 2296 2297 // (C++ 13.3.2p2): A candidate function having fewer than m 2298 // parameters is viable only if it has an ellipsis in its parameter 2299 // list (8.3.5). 2300 if (NumArgs > NumArgsInProto && !Proto->isVariadic()) { 2301 Candidate.Viable = false; 2302 return; 2303 } 2304 2305 // Function types don't have any default arguments, so just check if 2306 // we have enough arguments. 2307 if (NumArgs < NumArgsInProto) { 2308 // Not enough arguments. 2309 Candidate.Viable = false; 2310 return; 2311 } 2312 2313 // Determine the implicit conversion sequences for each of the 2314 // arguments. 2315 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2316 if (ArgIdx < NumArgsInProto) { 2317 // (C++ 13.3.2p3): for F to be a viable function, there shall 2318 // exist for each argument an implicit conversion sequence 2319 // (13.3.3.1) that converts that argument to the corresponding 2320 // parameter of F. 2321 QualType ParamType = Proto->getArgType(ArgIdx); 2322 Candidate.Conversions[ArgIdx + 1] 2323 = TryCopyInitialization(Args[ArgIdx], ParamType, 2324 /*SuppressUserConversions=*/false); 2325 if (Candidate.Conversions[ArgIdx + 1].ConversionKind 2326 == ImplicitConversionSequence::BadConversion) { 2327 Candidate.Viable = false; 2328 break; 2329 } 2330 } else { 2331 // (C++ 13.3.2p2): For the purposes of overload resolution, any 2332 // argument for which there is no corresponding parameter is 2333 // considered to ""match the ellipsis" (C+ 13.3.3.1.3). 2334 Candidate.Conversions[ArgIdx + 1].ConversionKind 2335 = ImplicitConversionSequence::EllipsisConversion; 2336 } 2337 } 2338} 2339 2340// FIXME: This will eventually be removed, once we've migrated all of 2341// the operator overloading logic over to the scheme used by binary 2342// operators, which works for template instantiation. 2343void Sema::AddOperatorCandidates(OverloadedOperatorKind Op, Scope *S, 2344 SourceLocation OpLoc, 2345 Expr **Args, unsigned NumArgs, 2346 OverloadCandidateSet& CandidateSet, 2347 SourceRange OpRange) { 2348 2349 FunctionSet Functions; 2350 2351 QualType T1 = Args[0]->getType(); 2352 QualType T2; 2353 if (NumArgs > 1) 2354 T2 = Args[1]->getType(); 2355 2356 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2357 LookupOverloadedOperatorName(Op, S, T1, T2, Functions); 2358 ArgumentDependentLookup(OpName, Args, NumArgs, Functions); 2359 AddFunctionCandidates(Functions, Args, NumArgs, CandidateSet); 2360 AddMemberOperatorCandidates(Op, OpLoc, Args, NumArgs, CandidateSet, OpRange); 2361 AddBuiltinOperatorCandidates(Op, Args, NumArgs, CandidateSet); 2362} 2363 2364/// \brief Add overload candidates for overloaded operators that are 2365/// member functions. 2366/// 2367/// Add the overloaded operator candidates that are member functions 2368/// for the operator Op that was used in an operator expression such 2369/// as "x Op y". , Args/NumArgs provides the operator arguments, and 2370/// CandidateSet will store the added overload candidates. (C++ 2371/// [over.match.oper]). 2372void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op, 2373 SourceLocation OpLoc, 2374 Expr **Args, unsigned NumArgs, 2375 OverloadCandidateSet& CandidateSet, 2376 SourceRange OpRange) { 2377 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 2378 2379 // C++ [over.match.oper]p3: 2380 // For a unary operator @ with an operand of a type whose 2381 // cv-unqualified version is T1, and for a binary operator @ with 2382 // a left operand of a type whose cv-unqualified version is T1 and 2383 // a right operand of a type whose cv-unqualified version is T2, 2384 // three sets of candidate functions, designated member 2385 // candidates, non-member candidates and built-in candidates, are 2386 // constructed as follows: 2387 QualType T1 = Args[0]->getType(); 2388 QualType T2; 2389 if (NumArgs > 1) 2390 T2 = Args[1]->getType(); 2391 2392 // -- If T1 is a class type, the set of member candidates is the 2393 // result of the qualified lookup of T1::operator@ 2394 // (13.3.1.1.1); otherwise, the set of member candidates is 2395 // empty. 2396 // FIXME: Lookup in base classes, too! 2397 if (const RecordType *T1Rec = T1->getAsRecordType()) { 2398 DeclContext::lookup_const_iterator Oper, OperEnd; 2399 for (llvm::tie(Oper, OperEnd) = T1Rec->getDecl()->lookup(Context, OpName); 2400 Oper != OperEnd; ++Oper) 2401 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Args[0], 2402 Args+1, NumArgs - 1, CandidateSet, 2403 /*SuppressUserConversions=*/false); 2404 } 2405} 2406 2407/// AddBuiltinCandidate - Add a candidate for a built-in 2408/// operator. ResultTy and ParamTys are the result and parameter types 2409/// of the built-in candidate, respectively. Args and NumArgs are the 2410/// arguments being passed to the candidate. IsAssignmentOperator 2411/// should be true when this built-in candidate is an assignment 2412/// operator. NumContextualBoolArguments is the number of arguments 2413/// (at the beginning of the argument list) that will be contextually 2414/// converted to bool. 2415void Sema::AddBuiltinCandidate(QualType ResultTy, QualType *ParamTys, 2416 Expr **Args, unsigned NumArgs, 2417 OverloadCandidateSet& CandidateSet, 2418 bool IsAssignmentOperator, 2419 unsigned NumContextualBoolArguments) { 2420 // Add this candidate 2421 CandidateSet.push_back(OverloadCandidate()); 2422 OverloadCandidate& Candidate = CandidateSet.back(); 2423 Candidate.Function = 0; 2424 Candidate.IsSurrogate = false; 2425 Candidate.IgnoreObjectArgument = false; 2426 Candidate.BuiltinTypes.ResultTy = ResultTy; 2427 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2428 Candidate.BuiltinTypes.ParamTypes[ArgIdx] = ParamTys[ArgIdx]; 2429 2430 // Determine the implicit conversion sequences for each of the 2431 // arguments. 2432 Candidate.Viable = true; 2433 Candidate.Conversions.resize(NumArgs); 2434 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) { 2435 // C++ [over.match.oper]p4: 2436 // For the built-in assignment operators, conversions of the 2437 // left operand are restricted as follows: 2438 // -- no temporaries are introduced to hold the left operand, and 2439 // -- no user-defined conversions are applied to the left 2440 // operand to achieve a type match with the left-most 2441 // parameter of a built-in candidate. 2442 // 2443 // We block these conversions by turning off user-defined 2444 // conversions, since that is the only way that initialization of 2445 // a reference to a non-class type can occur from something that 2446 // is not of the same type. 2447 if (ArgIdx < NumContextualBoolArguments) { 2448 assert(ParamTys[ArgIdx] == Context.BoolTy && 2449 "Contextual conversion to bool requires bool type"); 2450 Candidate.Conversions[ArgIdx] = TryContextuallyConvertToBool(Args[ArgIdx]); 2451 } else { 2452 Candidate.Conversions[ArgIdx] 2453 = TryCopyInitialization(Args[ArgIdx], ParamTys[ArgIdx], 2454 ArgIdx == 0 && IsAssignmentOperator); 2455 } 2456 if (Candidate.Conversions[ArgIdx].ConversionKind 2457 == ImplicitConversionSequence::BadConversion) { 2458 Candidate.Viable = false; 2459 break; 2460 } 2461 } 2462} 2463 2464/// BuiltinCandidateTypeSet - A set of types that will be used for the 2465/// candidate operator functions for built-in operators (C++ 2466/// [over.built]). The types are separated into pointer types and 2467/// enumeration types. 2468class BuiltinCandidateTypeSet { 2469 /// TypeSet - A set of types. 2470 typedef llvm::SmallPtrSet<QualType, 8> TypeSet; 2471 2472 /// PointerTypes - The set of pointer types that will be used in the 2473 /// built-in candidates. 2474 TypeSet PointerTypes; 2475 2476 /// EnumerationTypes - The set of enumeration types that will be 2477 /// used in the built-in candidates. 2478 TypeSet EnumerationTypes; 2479 2480 /// Context - The AST context in which we will build the type sets. 2481 ASTContext &Context; 2482 2483 bool AddWithMoreQualifiedTypeVariants(QualType Ty); 2484 2485public: 2486 /// iterator - Iterates through the types that are part of the set. 2487 typedef TypeSet::iterator iterator; 2488 2489 BuiltinCandidateTypeSet(ASTContext &Context) : Context(Context) { } 2490 2491 void AddTypesConvertedFrom(QualType Ty, bool AllowUserConversions, 2492 bool AllowExplicitConversions); 2493 2494 /// pointer_begin - First pointer type found; 2495 iterator pointer_begin() { return PointerTypes.begin(); } 2496 2497 /// pointer_end - Last pointer type found; 2498 iterator pointer_end() { return PointerTypes.end(); } 2499 2500 /// enumeration_begin - First enumeration type found; 2501 iterator enumeration_begin() { return EnumerationTypes.begin(); } 2502 2503 /// enumeration_end - Last enumeration type found; 2504 iterator enumeration_end() { return EnumerationTypes.end(); } 2505}; 2506 2507/// AddWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to 2508/// the set of pointer types along with any more-qualified variants of 2509/// that type. For example, if @p Ty is "int const *", this routine 2510/// will add "int const *", "int const volatile *", "int const 2511/// restrict *", and "int const volatile restrict *" to the set of 2512/// pointer types. Returns true if the add of @p Ty itself succeeded, 2513/// false otherwise. 2514bool BuiltinCandidateTypeSet::AddWithMoreQualifiedTypeVariants(QualType Ty) { 2515 // Insert this type. 2516 if (!PointerTypes.insert(Ty)) 2517 return false; 2518 2519 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2520 QualType PointeeTy = PointerTy->getPointeeType(); 2521 // FIXME: Optimize this so that we don't keep trying to add the same types. 2522 2523 // FIXME: Do we have to add CVR qualifiers at *all* levels to deal 2524 // with all pointer conversions that don't cast away constness? 2525 if (!PointeeTy.isConstQualified()) 2526 AddWithMoreQualifiedTypeVariants 2527 (Context.getPointerType(PointeeTy.withConst())); 2528 if (!PointeeTy.isVolatileQualified()) 2529 AddWithMoreQualifiedTypeVariants 2530 (Context.getPointerType(PointeeTy.withVolatile())); 2531 if (!PointeeTy.isRestrictQualified()) 2532 AddWithMoreQualifiedTypeVariants 2533 (Context.getPointerType(PointeeTy.withRestrict())); 2534 } 2535 2536 return true; 2537} 2538 2539/// AddTypesConvertedFrom - Add each of the types to which the type @p 2540/// Ty can be implicit converted to the given set of @p Types. We're 2541/// primarily interested in pointer types and enumeration types. 2542/// AllowUserConversions is true if we should look at the conversion 2543/// functions of a class type, and AllowExplicitConversions if we 2544/// should also include the explicit conversion functions of a class 2545/// type. 2546void 2547BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty, 2548 bool AllowUserConversions, 2549 bool AllowExplicitConversions) { 2550 // Only deal with canonical types. 2551 Ty = Context.getCanonicalType(Ty); 2552 2553 // Look through reference types; they aren't part of the type of an 2554 // expression for the purposes of conversions. 2555 if (const ReferenceType *RefTy = Ty->getAsReferenceType()) 2556 Ty = RefTy->getPointeeType(); 2557 2558 // We don't care about qualifiers on the type. 2559 Ty = Ty.getUnqualifiedType(); 2560 2561 if (const PointerType *PointerTy = Ty->getAsPointerType()) { 2562 QualType PointeeTy = PointerTy->getPointeeType(); 2563 2564 // Insert our type, and its more-qualified variants, into the set 2565 // of types. 2566 if (!AddWithMoreQualifiedTypeVariants(Ty)) 2567 return; 2568 2569 // Add 'cv void*' to our set of types. 2570 if (!Ty->isVoidType()) { 2571 QualType QualVoid 2572 = Context.VoidTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2573 AddWithMoreQualifiedTypeVariants(Context.getPointerType(QualVoid)); 2574 } 2575 2576 // If this is a pointer to a class type, add pointers to its bases 2577 // (with the same level of cv-qualification as the original 2578 // derived class, of course). 2579 if (const RecordType *PointeeRec = PointeeTy->getAsRecordType()) { 2580 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(PointeeRec->getDecl()); 2581 for (CXXRecordDecl::base_class_iterator Base = ClassDecl->bases_begin(); 2582 Base != ClassDecl->bases_end(); ++Base) { 2583 QualType BaseTy = Context.getCanonicalType(Base->getType()); 2584 BaseTy = BaseTy.getQualifiedType(PointeeTy.getCVRQualifiers()); 2585 2586 // Add the pointer type, recursively, so that we get all of 2587 // the indirect base classes, too. 2588 AddTypesConvertedFrom(Context.getPointerType(BaseTy), false, false); 2589 } 2590 } 2591 } else if (Ty->isEnumeralType()) { 2592 EnumerationTypes.insert(Ty); 2593 } else if (AllowUserConversions) { 2594 if (const RecordType *TyRec = Ty->getAsRecordType()) { 2595 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl()); 2596 // FIXME: Visit conversion functions in the base classes, too. 2597 OverloadedFunctionDecl *Conversions 2598 = ClassDecl->getConversionFunctions(); 2599 for (OverloadedFunctionDecl::function_iterator Func 2600 = Conversions->function_begin(); 2601 Func != Conversions->function_end(); ++Func) { 2602 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 2603 if (AllowExplicitConversions || !Conv->isExplicit()) 2604 AddTypesConvertedFrom(Conv->getConversionType(), false, false); 2605 } 2606 } 2607 } 2608} 2609 2610/// AddBuiltinOperatorCandidates - Add the appropriate built-in 2611/// operator overloads to the candidate set (C++ [over.built]), based 2612/// on the operator @p Op and the arguments given. For example, if the 2613/// operator is a binary '+', this routine might add "int 2614/// operator+(int, int)" to cover integer addition. 2615void 2616Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op, 2617 Expr **Args, unsigned NumArgs, 2618 OverloadCandidateSet& CandidateSet) { 2619 // The set of "promoted arithmetic types", which are the arithmetic 2620 // types are that preserved by promotion (C++ [over.built]p2). Note 2621 // that the first few of these types are the promoted integral 2622 // types; these types need to be first. 2623 // FIXME: What about complex? 2624 const unsigned FirstIntegralType = 0; 2625 const unsigned LastIntegralType = 13; 2626 const unsigned FirstPromotedIntegralType = 7, 2627 LastPromotedIntegralType = 13; 2628 const unsigned FirstPromotedArithmeticType = 7, 2629 LastPromotedArithmeticType = 16; 2630 const unsigned NumArithmeticTypes = 16; 2631 QualType ArithmeticTypes[NumArithmeticTypes] = { 2632 Context.BoolTy, Context.CharTy, Context.WCharTy, 2633 Context.SignedCharTy, Context.ShortTy, 2634 Context.UnsignedCharTy, Context.UnsignedShortTy, 2635 Context.IntTy, Context.LongTy, Context.LongLongTy, 2636 Context.UnsignedIntTy, Context.UnsignedLongTy, Context.UnsignedLongLongTy, 2637 Context.FloatTy, Context.DoubleTy, Context.LongDoubleTy 2638 }; 2639 2640 // Find all of the types that the arguments can convert to, but only 2641 // if the operator we're looking at has built-in operator candidates 2642 // that make use of these types. 2643 BuiltinCandidateTypeSet CandidateTypes(Context); 2644 if (Op == OO_Less || Op == OO_Greater || Op == OO_LessEqual || 2645 Op == OO_GreaterEqual || Op == OO_EqualEqual || Op == OO_ExclaimEqual || 2646 Op == OO_Plus || (Op == OO_Minus && NumArgs == 2) || Op == OO_Equal || 2647 Op == OO_PlusEqual || Op == OO_MinusEqual || Op == OO_Subscript || 2648 Op == OO_ArrowStar || Op == OO_PlusPlus || Op == OO_MinusMinus || 2649 (Op == OO_Star && NumArgs == 1)) { 2650 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 2651 CandidateTypes.AddTypesConvertedFrom(Args[ArgIdx]->getType(), 2652 true, 2653 (Op == OO_Exclaim || 2654 Op == OO_AmpAmp || 2655 Op == OO_PipePipe)); 2656 } 2657 2658 bool isComparison = false; 2659 switch (Op) { 2660 case OO_None: 2661 case NUM_OVERLOADED_OPERATORS: 2662 assert(false && "Expected an overloaded operator"); 2663 break; 2664 2665 case OO_Star: // '*' is either unary or binary 2666 if (NumArgs == 1) 2667 goto UnaryStar; 2668 else 2669 goto BinaryStar; 2670 break; 2671 2672 case OO_Plus: // '+' is either unary or binary 2673 if (NumArgs == 1) 2674 goto UnaryPlus; 2675 else 2676 goto BinaryPlus; 2677 break; 2678 2679 case OO_Minus: // '-' is either unary or binary 2680 if (NumArgs == 1) 2681 goto UnaryMinus; 2682 else 2683 goto BinaryMinus; 2684 break; 2685 2686 case OO_Amp: // '&' is either unary or binary 2687 if (NumArgs == 1) 2688 goto UnaryAmp; 2689 else 2690 goto BinaryAmp; 2691 2692 case OO_PlusPlus: 2693 case OO_MinusMinus: 2694 // C++ [over.built]p3: 2695 // 2696 // For every pair (T, VQ), where T is an arithmetic type, and VQ 2697 // is either volatile or empty, there exist candidate operator 2698 // functions of the form 2699 // 2700 // VQ T& operator++(VQ T&); 2701 // T operator++(VQ T&, int); 2702 // 2703 // C++ [over.built]p4: 2704 // 2705 // For every pair (T, VQ), where T is an arithmetic type other 2706 // than bool, and VQ is either volatile or empty, there exist 2707 // candidate operator functions of the form 2708 // 2709 // VQ T& operator--(VQ T&); 2710 // T operator--(VQ T&, int); 2711 for (unsigned Arith = (Op == OO_PlusPlus? 0 : 1); 2712 Arith < NumArithmeticTypes; ++Arith) { 2713 QualType ArithTy = ArithmeticTypes[Arith]; 2714 QualType ParamTypes[2] 2715 = { Context.getLValueReferenceType(ArithTy), Context.IntTy }; 2716 2717 // Non-volatile version. 2718 if (NumArgs == 1) 2719 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2720 else 2721 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2722 2723 // Volatile version 2724 ParamTypes[0] = Context.getLValueReferenceType(ArithTy.withVolatile()); 2725 if (NumArgs == 1) 2726 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2727 else 2728 AddBuiltinCandidate(ArithTy, ParamTypes, Args, 2, CandidateSet); 2729 } 2730 2731 // C++ [over.built]p5: 2732 // 2733 // For every pair (T, VQ), where T is a cv-qualified or 2734 // cv-unqualified object type, and VQ is either volatile or 2735 // empty, there exist candidate operator functions of the form 2736 // 2737 // T*VQ& operator++(T*VQ&); 2738 // T*VQ& operator--(T*VQ&); 2739 // T* operator++(T*VQ&, int); 2740 // T* operator--(T*VQ&, int); 2741 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2742 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2743 // Skip pointer types that aren't pointers to object types. 2744 if (!(*Ptr)->getAsPointerType()->getPointeeType()->isObjectType()) 2745 continue; 2746 2747 QualType ParamTypes[2] = { 2748 Context.getLValueReferenceType(*Ptr), Context.IntTy 2749 }; 2750 2751 // Without volatile 2752 if (NumArgs == 1) 2753 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2754 else 2755 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2756 2757 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 2758 // With volatile 2759 ParamTypes[0] = Context.getLValueReferenceType((*Ptr).withVolatile()); 2760 if (NumArgs == 1) 2761 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 1, CandidateSet); 2762 else 2763 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2764 } 2765 } 2766 break; 2767 2768 UnaryStar: 2769 // C++ [over.built]p6: 2770 // For every cv-qualified or cv-unqualified object type T, there 2771 // exist candidate operator functions of the form 2772 // 2773 // T& operator*(T*); 2774 // 2775 // C++ [over.built]p7: 2776 // For every function type T, there exist candidate operator 2777 // functions of the form 2778 // T& operator*(T*); 2779 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2780 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2781 QualType ParamTy = *Ptr; 2782 QualType PointeeTy = ParamTy->getAsPointerType()->getPointeeType(); 2783 AddBuiltinCandidate(Context.getLValueReferenceType(PointeeTy), 2784 &ParamTy, Args, 1, CandidateSet); 2785 } 2786 break; 2787 2788 UnaryPlus: 2789 // C++ [over.built]p8: 2790 // For every type T, there exist candidate operator functions of 2791 // the form 2792 // 2793 // T* operator+(T*); 2794 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2795 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2796 QualType ParamTy = *Ptr; 2797 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet); 2798 } 2799 2800 // Fall through 2801 2802 UnaryMinus: 2803 // C++ [over.built]p9: 2804 // For every promoted arithmetic type T, there exist candidate 2805 // operator functions of the form 2806 // 2807 // T operator+(T); 2808 // T operator-(T); 2809 for (unsigned Arith = FirstPromotedArithmeticType; 2810 Arith < LastPromotedArithmeticType; ++Arith) { 2811 QualType ArithTy = ArithmeticTypes[Arith]; 2812 AddBuiltinCandidate(ArithTy, &ArithTy, Args, 1, CandidateSet); 2813 } 2814 break; 2815 2816 case OO_Tilde: 2817 // C++ [over.built]p10: 2818 // For every promoted integral type T, there exist candidate 2819 // operator functions of the form 2820 // 2821 // T operator~(T); 2822 for (unsigned Int = FirstPromotedIntegralType; 2823 Int < LastPromotedIntegralType; ++Int) { 2824 QualType IntTy = ArithmeticTypes[Int]; 2825 AddBuiltinCandidate(IntTy, &IntTy, Args, 1, CandidateSet); 2826 } 2827 break; 2828 2829 case OO_New: 2830 case OO_Delete: 2831 case OO_Array_New: 2832 case OO_Array_Delete: 2833 case OO_Call: 2834 assert(false && "Special operators don't use AddBuiltinOperatorCandidates"); 2835 break; 2836 2837 case OO_Comma: 2838 UnaryAmp: 2839 case OO_Arrow: 2840 // C++ [over.match.oper]p3: 2841 // -- For the operator ',', the unary operator '&', or the 2842 // operator '->', the built-in candidates set is empty. 2843 break; 2844 2845 case OO_Less: 2846 case OO_Greater: 2847 case OO_LessEqual: 2848 case OO_GreaterEqual: 2849 case OO_EqualEqual: 2850 case OO_ExclaimEqual: 2851 // C++ [over.built]p15: 2852 // 2853 // For every pointer or enumeration type T, there exist 2854 // candidate operator functions of the form 2855 // 2856 // bool operator<(T, T); 2857 // bool operator>(T, T); 2858 // bool operator<=(T, T); 2859 // bool operator>=(T, T); 2860 // bool operator==(T, T); 2861 // bool operator!=(T, T); 2862 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 2863 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2864 QualType ParamTypes[2] = { *Ptr, *Ptr }; 2865 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2866 } 2867 for (BuiltinCandidateTypeSet::iterator Enum 2868 = CandidateTypes.enumeration_begin(); 2869 Enum != CandidateTypes.enumeration_end(); ++Enum) { 2870 QualType ParamTypes[2] = { *Enum, *Enum }; 2871 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet); 2872 } 2873 2874 // Fall through. 2875 isComparison = true; 2876 2877 BinaryPlus: 2878 BinaryMinus: 2879 if (!isComparison) { 2880 // We didn't fall through, so we must have OO_Plus or OO_Minus. 2881 2882 // C++ [over.built]p13: 2883 // 2884 // For every cv-qualified or cv-unqualified object type T 2885 // there exist candidate operator functions of the form 2886 // 2887 // T* operator+(T*, ptrdiff_t); 2888 // T& operator[](T*, ptrdiff_t); [BELOW] 2889 // T* operator-(T*, ptrdiff_t); 2890 // T* operator+(ptrdiff_t, T*); 2891 // T& operator[](ptrdiff_t, T*); [BELOW] 2892 // 2893 // C++ [over.built]p14: 2894 // 2895 // For every T, where T is a pointer to object type, there 2896 // exist candidate operator functions of the form 2897 // 2898 // ptrdiff_t operator-(T, T); 2899 for (BuiltinCandidateTypeSet::iterator Ptr 2900 = CandidateTypes.pointer_begin(); 2901 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 2902 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 2903 2904 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t) 2905 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2906 2907 if (Op == OO_Plus) { 2908 // T* operator+(ptrdiff_t, T*); 2909 ParamTypes[0] = ParamTypes[1]; 2910 ParamTypes[1] = *Ptr; 2911 AddBuiltinCandidate(*Ptr, ParamTypes, Args, 2, CandidateSet); 2912 } else { 2913 // ptrdiff_t operator-(T, T); 2914 ParamTypes[1] = *Ptr; 2915 AddBuiltinCandidate(Context.getPointerDiffType(), ParamTypes, 2916 Args, 2, CandidateSet); 2917 } 2918 } 2919 } 2920 // Fall through 2921 2922 case OO_Slash: 2923 BinaryStar: 2924 // C++ [over.built]p12: 2925 // 2926 // For every pair of promoted arithmetic types L and R, there 2927 // exist candidate operator functions of the form 2928 // 2929 // LR operator*(L, R); 2930 // LR operator/(L, R); 2931 // LR operator+(L, R); 2932 // LR operator-(L, R); 2933 // bool operator<(L, R); 2934 // bool operator>(L, R); 2935 // bool operator<=(L, R); 2936 // bool operator>=(L, R); 2937 // bool operator==(L, R); 2938 // bool operator!=(L, R); 2939 // 2940 // where LR is the result of the usual arithmetic conversions 2941 // between types L and R. 2942 for (unsigned Left = FirstPromotedArithmeticType; 2943 Left < LastPromotedArithmeticType; ++Left) { 2944 for (unsigned Right = FirstPromotedArithmeticType; 2945 Right < LastPromotedArithmeticType; ++Right) { 2946 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 2947 QualType Result 2948 = isComparison? Context.BoolTy 2949 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 2950 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 2951 } 2952 } 2953 break; 2954 2955 case OO_Percent: 2956 BinaryAmp: 2957 case OO_Caret: 2958 case OO_Pipe: 2959 case OO_LessLess: 2960 case OO_GreaterGreater: 2961 // C++ [over.built]p17: 2962 // 2963 // For every pair of promoted integral types L and R, there 2964 // exist candidate operator functions of the form 2965 // 2966 // LR operator%(L, R); 2967 // LR operator&(L, R); 2968 // LR operator^(L, R); 2969 // LR operator|(L, R); 2970 // L operator<<(L, R); 2971 // L operator>>(L, R); 2972 // 2973 // where LR is the result of the usual arithmetic conversions 2974 // between types L and R. 2975 for (unsigned Left = FirstPromotedIntegralType; 2976 Left < LastPromotedIntegralType; ++Left) { 2977 for (unsigned Right = FirstPromotedIntegralType; 2978 Right < LastPromotedIntegralType; ++Right) { 2979 QualType LandR[2] = { ArithmeticTypes[Left], ArithmeticTypes[Right] }; 2980 QualType Result = (Op == OO_LessLess || Op == OO_GreaterGreater) 2981 ? LandR[0] 2982 : UsualArithmeticConversionsType(LandR[0], LandR[1]); 2983 AddBuiltinCandidate(Result, LandR, Args, 2, CandidateSet); 2984 } 2985 } 2986 break; 2987 2988 case OO_Equal: 2989 // C++ [over.built]p20: 2990 // 2991 // For every pair (T, VQ), where T is an enumeration or 2992 // (FIXME:) pointer to member type and VQ is either volatile or 2993 // empty, there exist candidate operator functions of the form 2994 // 2995 // VQ T& operator=(VQ T&, T); 2996 for (BuiltinCandidateTypeSet::iterator Enum 2997 = CandidateTypes.enumeration_begin(); 2998 Enum != CandidateTypes.enumeration_end(); ++Enum) { 2999 QualType ParamTypes[2]; 3000 3001 // T& operator=(T&, T) 3002 ParamTypes[0] = Context.getLValueReferenceType(*Enum); 3003 ParamTypes[1] = *Enum; 3004 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3005 /*IsAssignmentOperator=*/false); 3006 3007 if (!Context.getCanonicalType(*Enum).isVolatileQualified()) { 3008 // volatile T& operator=(volatile T&, T) 3009 ParamTypes[0] = Context.getLValueReferenceType((*Enum).withVolatile()); 3010 ParamTypes[1] = *Enum; 3011 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3012 /*IsAssignmentOperator=*/false); 3013 } 3014 } 3015 // Fall through. 3016 3017 case OO_PlusEqual: 3018 case OO_MinusEqual: 3019 // C++ [over.built]p19: 3020 // 3021 // For every pair (T, VQ), where T is any type and VQ is either 3022 // volatile or empty, there exist candidate operator functions 3023 // of the form 3024 // 3025 // T*VQ& operator=(T*VQ&, T*); 3026 // 3027 // C++ [over.built]p21: 3028 // 3029 // For every pair (T, VQ), where T is a cv-qualified or 3030 // cv-unqualified object type and VQ is either volatile or 3031 // empty, there exist candidate operator functions of the form 3032 // 3033 // T*VQ& operator+=(T*VQ&, ptrdiff_t); 3034 // T*VQ& operator-=(T*VQ&, ptrdiff_t); 3035 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3036 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3037 QualType ParamTypes[2]; 3038 ParamTypes[1] = (Op == OO_Equal)? *Ptr : Context.getPointerDiffType(); 3039 3040 // non-volatile version 3041 ParamTypes[0] = Context.getLValueReferenceType(*Ptr); 3042 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3043 /*IsAssigmentOperator=*/Op == OO_Equal); 3044 3045 if (!Context.getCanonicalType(*Ptr).isVolatileQualified()) { 3046 // volatile version 3047 ParamTypes[0] = Context.getLValueReferenceType((*Ptr).withVolatile()); 3048 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3049 /*IsAssigmentOperator=*/Op == OO_Equal); 3050 } 3051 } 3052 // Fall through. 3053 3054 case OO_StarEqual: 3055 case OO_SlashEqual: 3056 // C++ [over.built]p18: 3057 // 3058 // For every triple (L, VQ, R), where L is an arithmetic type, 3059 // VQ is either volatile or empty, and R is a promoted 3060 // arithmetic type, there exist candidate operator functions of 3061 // the form 3062 // 3063 // VQ L& operator=(VQ L&, R); 3064 // VQ L& operator*=(VQ L&, R); 3065 // VQ L& operator/=(VQ L&, R); 3066 // VQ L& operator+=(VQ L&, R); 3067 // VQ L& operator-=(VQ L&, R); 3068 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) { 3069 for (unsigned Right = FirstPromotedArithmeticType; 3070 Right < LastPromotedArithmeticType; ++Right) { 3071 QualType ParamTypes[2]; 3072 ParamTypes[1] = ArithmeticTypes[Right]; 3073 3074 // Add this built-in operator as a candidate (VQ is empty). 3075 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3076 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3077 /*IsAssigmentOperator=*/Op == OO_Equal); 3078 3079 // Add this built-in operator as a candidate (VQ is 'volatile'). 3080 ParamTypes[0] = ArithmeticTypes[Left].withVolatile(); 3081 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3082 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet, 3083 /*IsAssigmentOperator=*/Op == OO_Equal); 3084 } 3085 } 3086 break; 3087 3088 case OO_PercentEqual: 3089 case OO_LessLessEqual: 3090 case OO_GreaterGreaterEqual: 3091 case OO_AmpEqual: 3092 case OO_CaretEqual: 3093 case OO_PipeEqual: 3094 // C++ [over.built]p22: 3095 // 3096 // For every triple (L, VQ, R), where L is an integral type, VQ 3097 // is either volatile or empty, and R is a promoted integral 3098 // type, there exist candidate operator functions of the form 3099 // 3100 // VQ L& operator%=(VQ L&, R); 3101 // VQ L& operator<<=(VQ L&, R); 3102 // VQ L& operator>>=(VQ L&, R); 3103 // VQ L& operator&=(VQ L&, R); 3104 // VQ L& operator^=(VQ L&, R); 3105 // VQ L& operator|=(VQ L&, R); 3106 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) { 3107 for (unsigned Right = FirstPromotedIntegralType; 3108 Right < LastPromotedIntegralType; ++Right) { 3109 QualType ParamTypes[2]; 3110 ParamTypes[1] = ArithmeticTypes[Right]; 3111 3112 // Add this built-in operator as a candidate (VQ is empty). 3113 ParamTypes[0] = Context.getLValueReferenceType(ArithmeticTypes[Left]); 3114 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3115 3116 // Add this built-in operator as a candidate (VQ is 'volatile'). 3117 ParamTypes[0] = ArithmeticTypes[Left]; 3118 ParamTypes[0].addVolatile(); 3119 ParamTypes[0] = Context.getLValueReferenceType(ParamTypes[0]); 3120 AddBuiltinCandidate(ParamTypes[0], ParamTypes, Args, 2, CandidateSet); 3121 } 3122 } 3123 break; 3124 3125 case OO_Exclaim: { 3126 // C++ [over.operator]p23: 3127 // 3128 // There also exist candidate operator functions of the form 3129 // 3130 // bool operator!(bool); 3131 // bool operator&&(bool, bool); [BELOW] 3132 // bool operator||(bool, bool); [BELOW] 3133 QualType ParamTy = Context.BoolTy; 3134 AddBuiltinCandidate(ParamTy, &ParamTy, Args, 1, CandidateSet, 3135 /*IsAssignmentOperator=*/false, 3136 /*NumContextualBoolArguments=*/1); 3137 break; 3138 } 3139 3140 case OO_AmpAmp: 3141 case OO_PipePipe: { 3142 // C++ [over.operator]p23: 3143 // 3144 // There also exist candidate operator functions of the form 3145 // 3146 // bool operator!(bool); [ABOVE] 3147 // bool operator&&(bool, bool); 3148 // bool operator||(bool, bool); 3149 QualType ParamTypes[2] = { Context.BoolTy, Context.BoolTy }; 3150 AddBuiltinCandidate(Context.BoolTy, ParamTypes, Args, 2, CandidateSet, 3151 /*IsAssignmentOperator=*/false, 3152 /*NumContextualBoolArguments=*/2); 3153 break; 3154 } 3155 3156 case OO_Subscript: 3157 // C++ [over.built]p13: 3158 // 3159 // For every cv-qualified or cv-unqualified object type T there 3160 // exist candidate operator functions of the form 3161 // 3162 // T* operator+(T*, ptrdiff_t); [ABOVE] 3163 // T& operator[](T*, ptrdiff_t); 3164 // T* operator-(T*, ptrdiff_t); [ABOVE] 3165 // T* operator+(ptrdiff_t, T*); [ABOVE] 3166 // T& operator[](ptrdiff_t, T*); 3167 for (BuiltinCandidateTypeSet::iterator Ptr = CandidateTypes.pointer_begin(); 3168 Ptr != CandidateTypes.pointer_end(); ++Ptr) { 3169 QualType ParamTypes[2] = { *Ptr, Context.getPointerDiffType() }; 3170 QualType PointeeType = (*Ptr)->getAsPointerType()->getPointeeType(); 3171 QualType ResultTy = Context.getLValueReferenceType(PointeeType); 3172 3173 // T& operator[](T*, ptrdiff_t) 3174 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3175 3176 // T& operator[](ptrdiff_t, T*); 3177 ParamTypes[0] = ParamTypes[1]; 3178 ParamTypes[1] = *Ptr; 3179 AddBuiltinCandidate(ResultTy, ParamTypes, Args, 2, CandidateSet); 3180 } 3181 break; 3182 3183 case OO_ArrowStar: 3184 // FIXME: No support for pointer-to-members yet. 3185 break; 3186 } 3187} 3188 3189/// \brief Add function candidates found via argument-dependent lookup 3190/// to the set of overloading candidates. 3191/// 3192/// This routine performs argument-dependent name lookup based on the 3193/// given function name (which may also be an operator name) and adds 3194/// all of the overload candidates found by ADL to the overload 3195/// candidate set (C++ [basic.lookup.argdep]). 3196void 3197Sema::AddArgumentDependentLookupCandidates(DeclarationName Name, 3198 Expr **Args, unsigned NumArgs, 3199 OverloadCandidateSet& CandidateSet) { 3200 FunctionSet Functions; 3201 3202 // Record all of the function candidates that we've already 3203 // added to the overload set, so that we don't add those same 3204 // candidates a second time. 3205 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3206 CandEnd = CandidateSet.end(); 3207 Cand != CandEnd; ++Cand) 3208 if (Cand->Function) 3209 Functions.insert(Cand->Function); 3210 3211 ArgumentDependentLookup(Name, Args, NumArgs, Functions); 3212 3213 // Erase all of the candidates we already knew about. 3214 // FIXME: This is suboptimal. Is there a better way? 3215 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3216 CandEnd = CandidateSet.end(); 3217 Cand != CandEnd; ++Cand) 3218 if (Cand->Function) 3219 Functions.erase(Cand->Function); 3220 3221 // For each of the ADL candidates we found, add it to the overload 3222 // set. 3223 for (FunctionSet::iterator Func = Functions.begin(), 3224 FuncEnd = Functions.end(); 3225 Func != FuncEnd; ++Func) 3226 AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet); 3227} 3228 3229/// isBetterOverloadCandidate - Determines whether the first overload 3230/// candidate is a better candidate than the second (C++ 13.3.3p1). 3231bool 3232Sema::isBetterOverloadCandidate(const OverloadCandidate& Cand1, 3233 const OverloadCandidate& Cand2) 3234{ 3235 // Define viable functions to be better candidates than non-viable 3236 // functions. 3237 if (!Cand2.Viable) 3238 return Cand1.Viable; 3239 else if (!Cand1.Viable) 3240 return false; 3241 3242 // C++ [over.match.best]p1: 3243 // 3244 // -- if F is a static member function, ICS1(F) is defined such 3245 // that ICS1(F) is neither better nor worse than ICS1(G) for 3246 // any function G, and, symmetrically, ICS1(G) is neither 3247 // better nor worse than ICS1(F). 3248 unsigned StartArg = 0; 3249 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument) 3250 StartArg = 1; 3251 3252 // (C++ 13.3.3p1): a viable function F1 is defined to be a better 3253 // function than another viable function F2 if for all arguments i, 3254 // ICSi(F1) is not a worse conversion sequence than ICSi(F2), and 3255 // then... 3256 unsigned NumArgs = Cand1.Conversions.size(); 3257 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch"); 3258 bool HasBetterConversion = false; 3259 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) { 3260 switch (CompareImplicitConversionSequences(Cand1.Conversions[ArgIdx], 3261 Cand2.Conversions[ArgIdx])) { 3262 case ImplicitConversionSequence::Better: 3263 // Cand1 has a better conversion sequence. 3264 HasBetterConversion = true; 3265 break; 3266 3267 case ImplicitConversionSequence::Worse: 3268 // Cand1 can't be better than Cand2. 3269 return false; 3270 3271 case ImplicitConversionSequence::Indistinguishable: 3272 // Do nothing. 3273 break; 3274 } 3275 } 3276 3277 if (HasBetterConversion) 3278 return true; 3279 3280 // FIXME: Several other bullets in (C++ 13.3.3p1) need to be 3281 // implemented, but they require template support. 3282 3283 // C++ [over.match.best]p1b4: 3284 // 3285 // -- the context is an initialization by user-defined conversion 3286 // (see 8.5, 13.3.1.5) and the standard conversion sequence 3287 // from the return type of F1 to the destination type (i.e., 3288 // the type of the entity being initialized) is a better 3289 // conversion sequence than the standard conversion sequence 3290 // from the return type of F2 to the destination type. 3291 if (Cand1.Function && Cand2.Function && 3292 isa<CXXConversionDecl>(Cand1.Function) && 3293 isa<CXXConversionDecl>(Cand2.Function)) { 3294 switch (CompareStandardConversionSequences(Cand1.FinalConversion, 3295 Cand2.FinalConversion)) { 3296 case ImplicitConversionSequence::Better: 3297 // Cand1 has a better conversion sequence. 3298 return true; 3299 3300 case ImplicitConversionSequence::Worse: 3301 // Cand1 can't be better than Cand2. 3302 return false; 3303 3304 case ImplicitConversionSequence::Indistinguishable: 3305 // Do nothing 3306 break; 3307 } 3308 } 3309 3310 return false; 3311} 3312 3313/// BestViableFunction - Computes the best viable function (C++ 13.3.3) 3314/// within an overload candidate set. If overloading is successful, 3315/// the result will be OR_Success and Best will be set to point to the 3316/// best viable function within the candidate set. Otherwise, one of 3317/// several kinds of errors will be returned; see 3318/// Sema::OverloadingResult. 3319Sema::OverloadingResult 3320Sema::BestViableFunction(OverloadCandidateSet& CandidateSet, 3321 OverloadCandidateSet::iterator& Best) 3322{ 3323 // Find the best viable function. 3324 Best = CandidateSet.end(); 3325 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3326 Cand != CandidateSet.end(); ++Cand) { 3327 if (Cand->Viable) { 3328 if (Best == CandidateSet.end() || isBetterOverloadCandidate(*Cand, *Best)) 3329 Best = Cand; 3330 } 3331 } 3332 3333 // If we didn't find any viable functions, abort. 3334 if (Best == CandidateSet.end()) 3335 return OR_No_Viable_Function; 3336 3337 // Make sure that this function is better than every other viable 3338 // function. If not, we have an ambiguity. 3339 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(); 3340 Cand != CandidateSet.end(); ++Cand) { 3341 if (Cand->Viable && 3342 Cand != Best && 3343 !isBetterOverloadCandidate(*Best, *Cand)) { 3344 Best = CandidateSet.end(); 3345 return OR_Ambiguous; 3346 } 3347 } 3348 3349 // Best is the best viable function. 3350 if (Best->Function && 3351 (Best->Function->isDeleted() || 3352 Best->Function->getAttr<UnavailableAttr>())) 3353 return OR_Deleted; 3354 3355 // If Best refers to a function that is either deleted (C++0x) or 3356 // unavailable (Clang extension) report an error. 3357 3358 return OR_Success; 3359} 3360 3361/// PrintOverloadCandidates - When overload resolution fails, prints 3362/// diagnostic messages containing the candidates in the candidate 3363/// set. If OnlyViable is true, only viable candidates will be printed. 3364void 3365Sema::PrintOverloadCandidates(OverloadCandidateSet& CandidateSet, 3366 bool OnlyViable) 3367{ 3368 OverloadCandidateSet::iterator Cand = CandidateSet.begin(), 3369 LastCand = CandidateSet.end(); 3370 for (; Cand != LastCand; ++Cand) { 3371 if (Cand->Viable || !OnlyViable) { 3372 if (Cand->Function) { 3373 if (Cand->Function->isDeleted() || 3374 Cand->Function->getAttr<UnavailableAttr>()) { 3375 // Deleted or "unavailable" function. 3376 Diag(Cand->Function->getLocation(), diag::err_ovl_candidate_deleted) 3377 << Cand->Function->isDeleted(); 3378 } else { 3379 // Normal function 3380 // FIXME: Give a better reason! 3381 Diag(Cand->Function->getLocation(), diag::err_ovl_candidate); 3382 } 3383 } else if (Cand->IsSurrogate) { 3384 // Desugar the type of the surrogate down to a function type, 3385 // retaining as many typedefs as possible while still showing 3386 // the function type (and, therefore, its parameter types). 3387 QualType FnType = Cand->Surrogate->getConversionType(); 3388 bool isLValueReference = false; 3389 bool isRValueReference = false; 3390 bool isPointer = false; 3391 if (const LValueReferenceType *FnTypeRef = 3392 FnType->getAsLValueReferenceType()) { 3393 FnType = FnTypeRef->getPointeeType(); 3394 isLValueReference = true; 3395 } else if (const RValueReferenceType *FnTypeRef = 3396 FnType->getAsRValueReferenceType()) { 3397 FnType = FnTypeRef->getPointeeType(); 3398 isRValueReference = true; 3399 } 3400 if (const PointerType *FnTypePtr = FnType->getAsPointerType()) { 3401 FnType = FnTypePtr->getPointeeType(); 3402 isPointer = true; 3403 } 3404 // Desugar down to a function type. 3405 FnType = QualType(FnType->getAsFunctionType(), 0); 3406 // Reconstruct the pointer/reference as appropriate. 3407 if (isPointer) FnType = Context.getPointerType(FnType); 3408 if (isRValueReference) FnType = Context.getRValueReferenceType(FnType); 3409 if (isLValueReference) FnType = Context.getLValueReferenceType(FnType); 3410 3411 Diag(Cand->Surrogate->getLocation(), diag::err_ovl_surrogate_cand) 3412 << FnType; 3413 } else { 3414 // FIXME: We need to get the identifier in here 3415 // FIXME: Do we want the error message to point at the 3416 // operator? (built-ins won't have a location) 3417 QualType FnType 3418 = Context.getFunctionType(Cand->BuiltinTypes.ResultTy, 3419 Cand->BuiltinTypes.ParamTypes, 3420 Cand->Conversions.size(), 3421 false, 0); 3422 3423 Diag(SourceLocation(), diag::err_ovl_builtin_candidate) << FnType; 3424 } 3425 } 3426 } 3427} 3428 3429/// ResolveAddressOfOverloadedFunction - Try to resolve the address of 3430/// an overloaded function (C++ [over.over]), where @p From is an 3431/// expression with overloaded function type and @p ToType is the type 3432/// we're trying to resolve to. For example: 3433/// 3434/// @code 3435/// int f(double); 3436/// int f(int); 3437/// 3438/// int (*pfd)(double) = f; // selects f(double) 3439/// @endcode 3440/// 3441/// This routine returns the resulting FunctionDecl if it could be 3442/// resolved, and NULL otherwise. When @p Complain is true, this 3443/// routine will emit diagnostics if there is an error. 3444FunctionDecl * 3445Sema::ResolveAddressOfOverloadedFunction(Expr *From, QualType ToType, 3446 bool Complain) { 3447 QualType FunctionType = ToType; 3448 bool IsMember = false; 3449 if (const PointerType *ToTypePtr = ToType->getAsPointerType()) 3450 FunctionType = ToTypePtr->getPointeeType(); 3451 else if (const ReferenceType *ToTypeRef = ToType->getAsReferenceType()) 3452 FunctionType = ToTypeRef->getPointeeType(); 3453 else if (const MemberPointerType *MemTypePtr = 3454 ToType->getAsMemberPointerType()) { 3455 FunctionType = MemTypePtr->getPointeeType(); 3456 IsMember = true; 3457 } 3458 3459 // We only look at pointers or references to functions. 3460 if (!FunctionType->isFunctionType()) 3461 return 0; 3462 3463 // Find the actual overloaded function declaration. 3464 OverloadedFunctionDecl *Ovl = 0; 3465 3466 // C++ [over.over]p1: 3467 // [...] [Note: any redundant set of parentheses surrounding the 3468 // overloaded function name is ignored (5.1). ] 3469 Expr *OvlExpr = From->IgnoreParens(); 3470 3471 // C++ [over.over]p1: 3472 // [...] The overloaded function name can be preceded by the & 3473 // operator. 3474 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(OvlExpr)) { 3475 if (UnOp->getOpcode() == UnaryOperator::AddrOf) 3476 OvlExpr = UnOp->getSubExpr()->IgnoreParens(); 3477 } 3478 3479 // Try to dig out the overloaded function. 3480 if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(OvlExpr)) 3481 Ovl = dyn_cast<OverloadedFunctionDecl>(DR->getDecl()); 3482 3483 // If there's no overloaded function declaration, we're done. 3484 if (!Ovl) 3485 return 0; 3486 3487 // Look through all of the overloaded functions, searching for one 3488 // whose type matches exactly. 3489 // FIXME: When templates or using declarations come along, we'll actually 3490 // have to deal with duplicates, partial ordering, etc. For now, we 3491 // can just do a simple search. 3492 FunctionType = Context.getCanonicalType(FunctionType.getUnqualifiedType()); 3493 for (OverloadedFunctionDecl::function_iterator Fun = Ovl->function_begin(); 3494 Fun != Ovl->function_end(); ++Fun) { 3495 // C++ [over.over]p3: 3496 // Non-member functions and static member functions match 3497 // targets of type "pointer-to-function" or "reference-to-function." 3498 // Nonstatic member functions match targets of 3499 // type "pointer-to-member-function." 3500 // Note that according to DR 247, the containing class does not matter. 3501 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(*Fun)) { 3502 // Skip non-static functions when converting to pointer, and static 3503 // when converting to member pointer. 3504 if (Method->isStatic() == IsMember) 3505 continue; 3506 } else if (IsMember) 3507 continue; 3508 3509 if (FunctionType == Context.getCanonicalType((*Fun)->getType())) 3510 return *Fun; 3511 } 3512 3513 return 0; 3514} 3515 3516/// ResolveOverloadedCallFn - Given the call expression that calls Fn 3517/// (which eventually refers to the declaration Func) and the call 3518/// arguments Args/NumArgs, attempt to resolve the function call down 3519/// to a specific function. If overload resolution succeeds, returns 3520/// the function declaration produced by overload 3521/// resolution. Otherwise, emits diagnostics, deletes all of the 3522/// arguments and Fn, and returns NULL. 3523FunctionDecl *Sema::ResolveOverloadedCallFn(Expr *Fn, NamedDecl *Callee, 3524 DeclarationName UnqualifiedName, 3525 SourceLocation LParenLoc, 3526 Expr **Args, unsigned NumArgs, 3527 SourceLocation *CommaLocs, 3528 SourceLocation RParenLoc, 3529 bool &ArgumentDependentLookup) { 3530 OverloadCandidateSet CandidateSet; 3531 3532 // Add the functions denoted by Callee to the set of candidate 3533 // functions. While we're doing so, track whether argument-dependent 3534 // lookup still applies, per: 3535 // 3536 // C++0x [basic.lookup.argdep]p3: 3537 // Let X be the lookup set produced by unqualified lookup (3.4.1) 3538 // and let Y be the lookup set produced by argument dependent 3539 // lookup (defined as follows). If X contains 3540 // 3541 // -- a declaration of a class member, or 3542 // 3543 // -- a block-scope function declaration that is not a 3544 // using-declaration, or 3545 // 3546 // -- a declaration that is neither a function or a function 3547 // template 3548 // 3549 // then Y is empty. 3550 if (OverloadedFunctionDecl *Ovl 3551 = dyn_cast_or_null<OverloadedFunctionDecl>(Callee)) { 3552 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 3553 FuncEnd = Ovl->function_end(); 3554 Func != FuncEnd; ++Func) { 3555 AddOverloadCandidate(*Func, Args, NumArgs, CandidateSet); 3556 3557 if ((*Func)->getDeclContext()->isRecord() || 3558 (*Func)->getDeclContext()->isFunctionOrMethod()) 3559 ArgumentDependentLookup = false; 3560 } 3561 } else if (FunctionDecl *Func = dyn_cast_or_null<FunctionDecl>(Callee)) { 3562 AddOverloadCandidate(Func, Args, NumArgs, CandidateSet); 3563 3564 if (Func->getDeclContext()->isRecord() || 3565 Func->getDeclContext()->isFunctionOrMethod()) 3566 ArgumentDependentLookup = false; 3567 } 3568 3569 if (Callee) 3570 UnqualifiedName = Callee->getDeclName(); 3571 3572 if (ArgumentDependentLookup) 3573 AddArgumentDependentLookupCandidates(UnqualifiedName, Args, NumArgs, 3574 CandidateSet); 3575 3576 OverloadCandidateSet::iterator Best; 3577 switch (BestViableFunction(CandidateSet, Best)) { 3578 case OR_Success: 3579 return Best->Function; 3580 3581 case OR_No_Viable_Function: 3582 Diag(Fn->getSourceRange().getBegin(), 3583 diag::err_ovl_no_viable_function_in_call) 3584 << UnqualifiedName << Fn->getSourceRange(); 3585 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3586 break; 3587 3588 case OR_Ambiguous: 3589 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_ambiguous_call) 3590 << UnqualifiedName << Fn->getSourceRange(); 3591 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3592 break; 3593 3594 case OR_Deleted: 3595 Diag(Fn->getSourceRange().getBegin(), diag::err_ovl_deleted_call) 3596 << Best->Function->isDeleted() 3597 << UnqualifiedName 3598 << Fn->getSourceRange(); 3599 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3600 break; 3601 } 3602 3603 // Overload resolution failed. Destroy all of the subexpressions and 3604 // return NULL. 3605 Fn->Destroy(Context); 3606 for (unsigned Arg = 0; Arg < NumArgs; ++Arg) 3607 Args[Arg]->Destroy(Context); 3608 return 0; 3609} 3610 3611/// \brief Create a unary operation that may resolve to an overloaded 3612/// operator. 3613/// 3614/// \param OpLoc The location of the operator itself (e.g., '*'). 3615/// 3616/// \param OpcIn The UnaryOperator::Opcode that describes this 3617/// operator. 3618/// 3619/// \param Functions The set of non-member functions that will be 3620/// considered by overload resolution. The caller needs to build this 3621/// set based on the context using, e.g., 3622/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 3623/// set should not contain any member functions; those will be added 3624/// by CreateOverloadedUnaryOp(). 3625/// 3626/// \param input The input argument. 3627Sema::OwningExprResult Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, 3628 unsigned OpcIn, 3629 FunctionSet &Functions, 3630 ExprArg input) { 3631 UnaryOperator::Opcode Opc = static_cast<UnaryOperator::Opcode>(OpcIn); 3632 Expr *Input = (Expr *)input.get(); 3633 3634 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc); 3635 assert(Op != OO_None && "Invalid opcode for overloaded unary operator"); 3636 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3637 3638 Expr *Args[2] = { Input, 0 }; 3639 unsigned NumArgs = 1; 3640 3641 // For post-increment and post-decrement, add the implicit '0' as 3642 // the second argument, so that we know this is a post-increment or 3643 // post-decrement. 3644 if (Opc == UnaryOperator::PostInc || Opc == UnaryOperator::PostDec) { 3645 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false); 3646 Args[1] = new (Context) IntegerLiteral(Zero, Context.IntTy, 3647 SourceLocation()); 3648 NumArgs = 2; 3649 } 3650 3651 if (Input->isTypeDependent()) { 3652 OverloadedFunctionDecl *Overloads 3653 = OverloadedFunctionDecl::Create(Context, CurContext, OpName); 3654 for (FunctionSet::iterator Func = Functions.begin(), 3655 FuncEnd = Functions.end(); 3656 Func != FuncEnd; ++Func) 3657 Overloads->addOverload(*Func); 3658 3659 DeclRefExpr *Fn = new (Context) DeclRefExpr(Overloads, Context.OverloadTy, 3660 OpLoc, false, false); 3661 3662 input.release(); 3663 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 3664 &Args[0], NumArgs, 3665 Context.DependentTy, 3666 OpLoc)); 3667 } 3668 3669 // Build an empty overload set. 3670 OverloadCandidateSet CandidateSet; 3671 3672 // Add the candidates from the given function set. 3673 AddFunctionCandidates(Functions, &Args[0], NumArgs, CandidateSet, false); 3674 3675 // Add operator candidates that are member functions. 3676 AddMemberOperatorCandidates(Op, OpLoc, &Args[0], NumArgs, CandidateSet); 3677 3678 // Add builtin operator candidates. 3679 AddBuiltinOperatorCandidates(Op, &Args[0], NumArgs, CandidateSet); 3680 3681 // Perform overload resolution. 3682 OverloadCandidateSet::iterator Best; 3683 switch (BestViableFunction(CandidateSet, Best)) { 3684 case OR_Success: { 3685 // We found a built-in operator or an overloaded operator. 3686 FunctionDecl *FnDecl = Best->Function; 3687 3688 if (FnDecl) { 3689 // We matched an overloaded operator. Build a call to that 3690 // operator. 3691 3692 // Convert the arguments. 3693 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 3694 if (PerformObjectArgumentInitialization(Input, Method)) 3695 return ExprError(); 3696 } else { 3697 // Convert the arguments. 3698 if (PerformCopyInitialization(Input, 3699 FnDecl->getParamDecl(0)->getType(), 3700 "passing")) 3701 return ExprError(); 3702 } 3703 3704 // Determine the result type 3705 QualType ResultTy 3706 = FnDecl->getType()->getAsFunctionType()->getResultType(); 3707 ResultTy = ResultTy.getNonReferenceType(); 3708 3709 // Build the actual expression node. 3710 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 3711 SourceLocation()); 3712 UsualUnaryConversions(FnExpr); 3713 3714 input.release(); 3715 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 3716 &Input, 1, ResultTy, 3717 OpLoc)); 3718 } else { 3719 // We matched a built-in operator. Convert the arguments, then 3720 // break out so that we will build the appropriate built-in 3721 // operator node. 3722 if (PerformImplicitConversion(Input, Best->BuiltinTypes.ParamTypes[0], 3723 Best->Conversions[0], "passing")) 3724 return ExprError(); 3725 3726 break; 3727 } 3728 } 3729 3730 case OR_No_Viable_Function: 3731 // No viable function; fall through to handling this as a 3732 // built-in operator, which will produce an error message for us. 3733 break; 3734 3735 case OR_Ambiguous: 3736 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 3737 << UnaryOperator::getOpcodeStr(Opc) 3738 << Input->getSourceRange(); 3739 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3740 return ExprError(); 3741 3742 case OR_Deleted: 3743 Diag(OpLoc, diag::err_ovl_deleted_oper) 3744 << Best->Function->isDeleted() 3745 << UnaryOperator::getOpcodeStr(Opc) 3746 << Input->getSourceRange(); 3747 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3748 return ExprError(); 3749 } 3750 3751 // Either we found no viable overloaded operator or we matched a 3752 // built-in operator. In either case, fall through to trying to 3753 // build a built-in operation. 3754 input.release(); 3755 return CreateBuiltinUnaryOp(OpLoc, Opc, Owned(Input)); 3756} 3757 3758/// \brief Create a binary operation that may resolve to an overloaded 3759/// operator. 3760/// 3761/// \param OpLoc The location of the operator itself (e.g., '+'). 3762/// 3763/// \param OpcIn The BinaryOperator::Opcode that describes this 3764/// operator. 3765/// 3766/// \param Functions The set of non-member functions that will be 3767/// considered by overload resolution. The caller needs to build this 3768/// set based on the context using, e.g., 3769/// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This 3770/// set should not contain any member functions; those will be added 3771/// by CreateOverloadedBinOp(). 3772/// 3773/// \param LHS Left-hand argument. 3774/// \param RHS Right-hand argument. 3775Sema::OwningExprResult 3776Sema::CreateOverloadedBinOp(SourceLocation OpLoc, 3777 unsigned OpcIn, 3778 FunctionSet &Functions, 3779 Expr *LHS, Expr *RHS) { 3780 Expr *Args[2] = { LHS, RHS }; 3781 3782 BinaryOperator::Opcode Opc = static_cast<BinaryOperator::Opcode>(OpcIn); 3783 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc); 3784 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op); 3785 3786 // If either side is type-dependent, create an appropriate dependent 3787 // expression. 3788 if (LHS->isTypeDependent() || RHS->isTypeDependent()) { 3789 // .* cannot be overloaded. 3790 if (Opc == BinaryOperator::PtrMemD) 3791 return Owned(new (Context) BinaryOperator(LHS, RHS, Opc, 3792 Context.DependentTy, OpLoc)); 3793 3794 OverloadedFunctionDecl *Overloads 3795 = OverloadedFunctionDecl::Create(Context, CurContext, OpName); 3796 for (FunctionSet::iterator Func = Functions.begin(), 3797 FuncEnd = Functions.end(); 3798 Func != FuncEnd; ++Func) 3799 Overloads->addOverload(*Func); 3800 3801 DeclRefExpr *Fn = new (Context) DeclRefExpr(Overloads, Context.OverloadTy, 3802 OpLoc, false, false); 3803 3804 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, Fn, 3805 Args, 2, 3806 Context.DependentTy, 3807 OpLoc)); 3808 } 3809 3810 // If this is the .* operator, which is not overloadable, just 3811 // create a built-in binary operator. 3812 if (Opc == BinaryOperator::PtrMemD) 3813 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3814 3815 // If this is one of the assignment operators, we only perform 3816 // overload resolution if the left-hand side is a class or 3817 // enumeration type (C++ [expr.ass]p3). 3818 if (Opc >= BinaryOperator::Assign && Opc <= BinaryOperator::OrAssign && 3819 !LHS->getType()->isOverloadableType()) 3820 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3821 3822 // Build an empty overload set. 3823 OverloadCandidateSet CandidateSet; 3824 3825 // Add the candidates from the given function set. 3826 AddFunctionCandidates(Functions, Args, 2, CandidateSet, false); 3827 3828 // Add operator candidates that are member functions. 3829 AddMemberOperatorCandidates(Op, OpLoc, Args, 2, CandidateSet); 3830 3831 // Add builtin operator candidates. 3832 AddBuiltinOperatorCandidates(Op, Args, 2, CandidateSet); 3833 3834 // Perform overload resolution. 3835 OverloadCandidateSet::iterator Best; 3836 switch (BestViableFunction(CandidateSet, Best)) { 3837 case OR_Success: { 3838 // We found a built-in operator or an overloaded operator. 3839 FunctionDecl *FnDecl = Best->Function; 3840 3841 if (FnDecl) { 3842 // We matched an overloaded operator. Build a call to that 3843 // operator. 3844 3845 // Convert the arguments. 3846 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) { 3847 if (PerformObjectArgumentInitialization(LHS, Method) || 3848 PerformCopyInitialization(RHS, FnDecl->getParamDecl(0)->getType(), 3849 "passing")) 3850 return ExprError(); 3851 } else { 3852 // Convert the arguments. 3853 if (PerformCopyInitialization(LHS, FnDecl->getParamDecl(0)->getType(), 3854 "passing") || 3855 PerformCopyInitialization(RHS, FnDecl->getParamDecl(1)->getType(), 3856 "passing")) 3857 return ExprError(); 3858 } 3859 3860 // Determine the result type 3861 QualType ResultTy 3862 = FnDecl->getType()->getAsFunctionType()->getResultType(); 3863 ResultTy = ResultTy.getNonReferenceType(); 3864 3865 // Build the actual expression node. 3866 Expr *FnExpr = new (Context) DeclRefExpr(FnDecl, FnDecl->getType(), 3867 SourceLocation()); 3868 UsualUnaryConversions(FnExpr); 3869 3870 return Owned(new (Context) CXXOperatorCallExpr(Context, Op, FnExpr, 3871 Args, 2, ResultTy, 3872 OpLoc)); 3873 } else { 3874 // We matched a built-in operator. Convert the arguments, then 3875 // break out so that we will build the appropriate built-in 3876 // operator node. 3877 if (PerformImplicitConversion(LHS, Best->BuiltinTypes.ParamTypes[0], 3878 Best->Conversions[0], "passing") || 3879 PerformImplicitConversion(RHS, Best->BuiltinTypes.ParamTypes[1], 3880 Best->Conversions[1], "passing")) 3881 return ExprError(); 3882 3883 break; 3884 } 3885 } 3886 3887 case OR_No_Viable_Function: 3888 // No viable function; fall through to handling this as a 3889 // built-in operator, which will produce an error message for us. 3890 break; 3891 3892 case OR_Ambiguous: 3893 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 3894 << BinaryOperator::getOpcodeStr(Opc) 3895 << LHS->getSourceRange() << RHS->getSourceRange(); 3896 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3897 return ExprError(); 3898 3899 case OR_Deleted: 3900 Diag(OpLoc, diag::err_ovl_deleted_oper) 3901 << Best->Function->isDeleted() 3902 << BinaryOperator::getOpcodeStr(Opc) 3903 << LHS->getSourceRange() << RHS->getSourceRange(); 3904 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 3905 return ExprError(); 3906 } 3907 3908 // Either we found no viable overloaded operator or we matched a 3909 // built-in operator. In either case, try to build a built-in 3910 // operation. 3911 return CreateBuiltinBinOp(OpLoc, Opc, LHS, RHS); 3912} 3913 3914/// BuildCallToMemberFunction - Build a call to a member 3915/// function. MemExpr is the expression that refers to the member 3916/// function (and includes the object parameter), Args/NumArgs are the 3917/// arguments to the function call (not including the object 3918/// parameter). The caller needs to validate that the member 3919/// expression refers to a member function or an overloaded member 3920/// function. 3921Sema::ExprResult 3922Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE, 3923 SourceLocation LParenLoc, Expr **Args, 3924 unsigned NumArgs, SourceLocation *CommaLocs, 3925 SourceLocation RParenLoc) { 3926 // Dig out the member expression. This holds both the object 3927 // argument and the member function we're referring to. 3928 MemberExpr *MemExpr = 0; 3929 if (ParenExpr *ParenE = dyn_cast<ParenExpr>(MemExprE)) 3930 MemExpr = dyn_cast<MemberExpr>(ParenE->getSubExpr()); 3931 else 3932 MemExpr = dyn_cast<MemberExpr>(MemExprE); 3933 assert(MemExpr && "Building member call without member expression"); 3934 3935 // Extract the object argument. 3936 Expr *ObjectArg = MemExpr->getBase(); 3937 if (MemExpr->isArrow()) 3938 ObjectArg = new (Context) UnaryOperator(ObjectArg, UnaryOperator::Deref, 3939 ObjectArg->getType()->getAsPointerType()->getPointeeType(), 3940 ObjectArg->getLocStart()); 3941 CXXMethodDecl *Method = 0; 3942 if (OverloadedFunctionDecl *Ovl 3943 = dyn_cast<OverloadedFunctionDecl>(MemExpr->getMemberDecl())) { 3944 // Add overload candidates 3945 OverloadCandidateSet CandidateSet; 3946 for (OverloadedFunctionDecl::function_iterator Func = Ovl->function_begin(), 3947 FuncEnd = Ovl->function_end(); 3948 Func != FuncEnd; ++Func) { 3949 assert(isa<CXXMethodDecl>(*Func) && "Function is not a method"); 3950 Method = cast<CXXMethodDecl>(*Func); 3951 AddMethodCandidate(Method, ObjectArg, Args, NumArgs, CandidateSet, 3952 /*SuppressUserConversions=*/false); 3953 } 3954 3955 OverloadCandidateSet::iterator Best; 3956 switch (BestViableFunction(CandidateSet, Best)) { 3957 case OR_Success: 3958 Method = cast<CXXMethodDecl>(Best->Function); 3959 break; 3960 3961 case OR_No_Viable_Function: 3962 Diag(MemExpr->getSourceRange().getBegin(), 3963 diag::err_ovl_no_viable_member_function_in_call) 3964 << Ovl->getDeclName() << MemExprE->getSourceRange(); 3965 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3966 // FIXME: Leaking incoming expressions! 3967 return true; 3968 3969 case OR_Ambiguous: 3970 Diag(MemExpr->getSourceRange().getBegin(), 3971 diag::err_ovl_ambiguous_member_call) 3972 << Ovl->getDeclName() << MemExprE->getSourceRange(); 3973 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3974 // FIXME: Leaking incoming expressions! 3975 return true; 3976 3977 case OR_Deleted: 3978 Diag(MemExpr->getSourceRange().getBegin(), 3979 diag::err_ovl_deleted_member_call) 3980 << Best->Function->isDeleted() 3981 << Ovl->getDeclName() << MemExprE->getSourceRange(); 3982 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 3983 // FIXME: Leaking incoming expressions! 3984 return true; 3985 } 3986 3987 FixOverloadedFunctionReference(MemExpr, Method); 3988 } else { 3989 Method = dyn_cast<CXXMethodDecl>(MemExpr->getMemberDecl()); 3990 } 3991 3992 assert(Method && "Member call to something that isn't a method?"); 3993 ExprOwningPtr<CXXMemberCallExpr> 3994 TheCall(this, new (Context) CXXMemberCallExpr(Context, MemExpr, Args, 3995 NumArgs, 3996 Method->getResultType().getNonReferenceType(), 3997 RParenLoc)); 3998 3999 // Convert the object argument (for a non-static member function call). 4000 if (!Method->isStatic() && 4001 PerformObjectArgumentInitialization(ObjectArg, Method)) 4002 return true; 4003 MemExpr->setBase(ObjectArg); 4004 4005 // Convert the rest of the arguments 4006 const FunctionProtoType *Proto = cast<FunctionProtoType>(Method->getType()); 4007 if (ConvertArgumentsForCall(&*TheCall, MemExpr, Method, Proto, Args, NumArgs, 4008 RParenLoc)) 4009 return true; 4010 4011 return CheckFunctionCall(Method, TheCall.take()).release(); 4012} 4013 4014/// BuildCallToObjectOfClassType - Build a call to an object of class 4015/// type (C++ [over.call.object]), which can end up invoking an 4016/// overloaded function call operator (@c operator()) or performing a 4017/// user-defined conversion on the object argument. 4018Sema::ExprResult 4019Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Object, 4020 SourceLocation LParenLoc, 4021 Expr **Args, unsigned NumArgs, 4022 SourceLocation *CommaLocs, 4023 SourceLocation RParenLoc) { 4024 assert(Object->getType()->isRecordType() && "Requires object type argument"); 4025 const RecordType *Record = Object->getType()->getAsRecordType(); 4026 4027 // C++ [over.call.object]p1: 4028 // If the primary-expression E in the function call syntax 4029 // evaluates to a class object of type “cv T”, then the set of 4030 // candidate functions includes at least the function call 4031 // operators of T. The function call operators of T are obtained by 4032 // ordinary lookup of the name operator() in the context of 4033 // (E).operator(). 4034 OverloadCandidateSet CandidateSet; 4035 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call); 4036 DeclContext::lookup_const_iterator Oper, OperEnd; 4037 for (llvm::tie(Oper, OperEnd) = Record->getDecl()->lookup(Context, OpName); 4038 Oper != OperEnd; ++Oper) 4039 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Object, Args, NumArgs, 4040 CandidateSet, /*SuppressUserConversions=*/false); 4041 4042 // C++ [over.call.object]p2: 4043 // In addition, for each conversion function declared in T of the 4044 // form 4045 // 4046 // operator conversion-type-id () cv-qualifier; 4047 // 4048 // where cv-qualifier is the same cv-qualification as, or a 4049 // greater cv-qualification than, cv, and where conversion-type-id 4050 // denotes the type "pointer to function of (P1,...,Pn) returning 4051 // R", or the type "reference to pointer to function of 4052 // (P1,...,Pn) returning R", or the type "reference to function 4053 // of (P1,...,Pn) returning R", a surrogate call function [...] 4054 // is also considered as a candidate function. Similarly, 4055 // surrogate call functions are added to the set of candidate 4056 // functions for each conversion function declared in an 4057 // accessible base class provided the function is not hidden 4058 // within T by another intervening declaration. 4059 // 4060 // FIXME: Look in base classes for more conversion operators! 4061 OverloadedFunctionDecl *Conversions 4062 = cast<CXXRecordDecl>(Record->getDecl())->getConversionFunctions(); 4063 for (OverloadedFunctionDecl::function_iterator 4064 Func = Conversions->function_begin(), 4065 FuncEnd = Conversions->function_end(); 4066 Func != FuncEnd; ++Func) { 4067 CXXConversionDecl *Conv = cast<CXXConversionDecl>(*Func); 4068 4069 // Strip the reference type (if any) and then the pointer type (if 4070 // any) to get down to what might be a function type. 4071 QualType ConvType = Conv->getConversionType().getNonReferenceType(); 4072 if (const PointerType *ConvPtrType = ConvType->getAsPointerType()) 4073 ConvType = ConvPtrType->getPointeeType(); 4074 4075 if (const FunctionProtoType *Proto = ConvType->getAsFunctionProtoType()) 4076 AddSurrogateCandidate(Conv, Proto, Object, Args, NumArgs, CandidateSet); 4077 } 4078 4079 // Perform overload resolution. 4080 OverloadCandidateSet::iterator Best; 4081 switch (BestViableFunction(CandidateSet, Best)) { 4082 case OR_Success: 4083 // Overload resolution succeeded; we'll build the appropriate call 4084 // below. 4085 break; 4086 4087 case OR_No_Viable_Function: 4088 Diag(Object->getSourceRange().getBegin(), 4089 diag::err_ovl_no_viable_object_call) 4090 << Object->getType() << Object->getSourceRange(); 4091 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4092 break; 4093 4094 case OR_Ambiguous: 4095 Diag(Object->getSourceRange().getBegin(), 4096 diag::err_ovl_ambiguous_object_call) 4097 << Object->getType() << Object->getSourceRange(); 4098 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4099 break; 4100 4101 case OR_Deleted: 4102 Diag(Object->getSourceRange().getBegin(), 4103 diag::err_ovl_deleted_object_call) 4104 << Best->Function->isDeleted() 4105 << Object->getType() << Object->getSourceRange(); 4106 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4107 break; 4108 } 4109 4110 if (Best == CandidateSet.end()) { 4111 // We had an error; delete all of the subexpressions and return 4112 // the error. 4113 Object->Destroy(Context); 4114 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4115 Args[ArgIdx]->Destroy(Context); 4116 return true; 4117 } 4118 4119 if (Best->Function == 0) { 4120 // Since there is no function declaration, this is one of the 4121 // surrogate candidates. Dig out the conversion function. 4122 CXXConversionDecl *Conv 4123 = cast<CXXConversionDecl>( 4124 Best->Conversions[0].UserDefined.ConversionFunction); 4125 4126 // We selected one of the surrogate functions that converts the 4127 // object parameter to a function pointer. Perform the conversion 4128 // on the object argument, then let ActOnCallExpr finish the job. 4129 // FIXME: Represent the user-defined conversion in the AST! 4130 ImpCastExprToType(Object, 4131 Conv->getConversionType().getNonReferenceType(), 4132 Conv->getConversionType()->isLValueReferenceType()); 4133 return ActOnCallExpr(S, ExprArg(*this, Object), LParenLoc, 4134 MultiExprArg(*this, (ExprTy**)Args, NumArgs), 4135 CommaLocs, RParenLoc).release(); 4136 } 4137 4138 // We found an overloaded operator(). Build a CXXOperatorCallExpr 4139 // that calls this method, using Object for the implicit object 4140 // parameter and passing along the remaining arguments. 4141 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 4142 const FunctionProtoType *Proto = Method->getType()->getAsFunctionProtoType(); 4143 4144 unsigned NumArgsInProto = Proto->getNumArgs(); 4145 unsigned NumArgsToCheck = NumArgs; 4146 4147 // Build the full argument list for the method call (the 4148 // implicit object parameter is placed at the beginning of the 4149 // list). 4150 Expr **MethodArgs; 4151 if (NumArgs < NumArgsInProto) { 4152 NumArgsToCheck = NumArgsInProto; 4153 MethodArgs = new Expr*[NumArgsInProto + 1]; 4154 } else { 4155 MethodArgs = new Expr*[NumArgs + 1]; 4156 } 4157 MethodArgs[0] = Object; 4158 for (unsigned ArgIdx = 0; ArgIdx < NumArgs; ++ArgIdx) 4159 MethodArgs[ArgIdx + 1] = Args[ArgIdx]; 4160 4161 Expr *NewFn = new (Context) DeclRefExpr(Method, Method->getType(), 4162 SourceLocation()); 4163 UsualUnaryConversions(NewFn); 4164 4165 // Once we've built TheCall, all of the expressions are properly 4166 // owned. 4167 QualType ResultTy = Method->getResultType().getNonReferenceType(); 4168 ExprOwningPtr<CXXOperatorCallExpr> 4169 TheCall(this, new (Context) CXXOperatorCallExpr(Context, OO_Call, NewFn, 4170 MethodArgs, NumArgs + 1, 4171 ResultTy, RParenLoc)); 4172 delete [] MethodArgs; 4173 4174 // We may have default arguments. If so, we need to allocate more 4175 // slots in the call for them. 4176 if (NumArgs < NumArgsInProto) 4177 TheCall->setNumArgs(Context, NumArgsInProto + 1); 4178 else if (NumArgs > NumArgsInProto) 4179 NumArgsToCheck = NumArgsInProto; 4180 4181 // Initialize the implicit object parameter. 4182 if (PerformObjectArgumentInitialization(Object, Method)) 4183 return true; 4184 TheCall->setArg(0, Object); 4185 4186 // Check the argument types. 4187 for (unsigned i = 0; i != NumArgsToCheck; i++) { 4188 Expr *Arg; 4189 if (i < NumArgs) { 4190 Arg = Args[i]; 4191 4192 // Pass the argument. 4193 QualType ProtoArgType = Proto->getArgType(i); 4194 if (PerformCopyInitialization(Arg, ProtoArgType, "passing")) 4195 return true; 4196 } else { 4197 Arg = new (Context) CXXDefaultArgExpr(Method->getParamDecl(i)); 4198 } 4199 4200 TheCall->setArg(i + 1, Arg); 4201 } 4202 4203 // If this is a variadic call, handle args passed through "...". 4204 if (Proto->isVariadic()) { 4205 // Promote the arguments (C99 6.5.2.2p7). 4206 for (unsigned i = NumArgsInProto; i != NumArgs; i++) { 4207 Expr *Arg = Args[i]; 4208 4209 DefaultVariadicArgumentPromotion(Arg, VariadicMethod); 4210 TheCall->setArg(i + 1, Arg); 4211 } 4212 } 4213 4214 return CheckFunctionCall(Method, TheCall.take()).release(); 4215} 4216 4217/// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator-> 4218/// (if one exists), where @c Base is an expression of class type and 4219/// @c Member is the name of the member we're trying to find. 4220Action::ExprResult 4221Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc, 4222 SourceLocation MemberLoc, 4223 IdentifierInfo &Member) { 4224 assert(Base->getType()->isRecordType() && "left-hand side must have class type"); 4225 4226 // C++ [over.ref]p1: 4227 // 4228 // [...] An expression x->m is interpreted as (x.operator->())->m 4229 // for a class object x of type T if T::operator->() exists and if 4230 // the operator is selected as the best match function by the 4231 // overload resolution mechanism (13.3). 4232 // FIXME: look in base classes. 4233 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Arrow); 4234 OverloadCandidateSet CandidateSet; 4235 const RecordType *BaseRecord = Base->getType()->getAsRecordType(); 4236 4237 DeclContext::lookup_const_iterator Oper, OperEnd; 4238 for (llvm::tie(Oper, OperEnd) 4239 = BaseRecord->getDecl()->lookup(Context, OpName); 4240 Oper != OperEnd; ++Oper) 4241 AddMethodCandidate(cast<CXXMethodDecl>(*Oper), Base, 0, 0, CandidateSet, 4242 /*SuppressUserConversions=*/false); 4243 4244 ExprOwningPtr<Expr> BasePtr(this, Base); 4245 4246 // Perform overload resolution. 4247 OverloadCandidateSet::iterator Best; 4248 switch (BestViableFunction(CandidateSet, Best)) { 4249 case OR_Success: 4250 // Overload resolution succeeded; we'll build the call below. 4251 break; 4252 4253 case OR_No_Viable_Function: 4254 if (CandidateSet.empty()) 4255 Diag(OpLoc, diag::err_typecheck_member_reference_arrow) 4256 << BasePtr->getType() << BasePtr->getSourceRange(); 4257 else 4258 Diag(OpLoc, diag::err_ovl_no_viable_oper) 4259 << "operator->" << BasePtr->getSourceRange(); 4260 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/false); 4261 return true; 4262 4263 case OR_Ambiguous: 4264 Diag(OpLoc, diag::err_ovl_ambiguous_oper) 4265 << "operator->" << BasePtr->getSourceRange(); 4266 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4267 return true; 4268 4269 case OR_Deleted: 4270 Diag(OpLoc, diag::err_ovl_deleted_oper) 4271 << Best->Function->isDeleted() 4272 << "operator->" << BasePtr->getSourceRange(); 4273 PrintOverloadCandidates(CandidateSet, /*OnlyViable=*/true); 4274 return true; 4275 } 4276 4277 // Convert the object parameter. 4278 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function); 4279 if (PerformObjectArgumentInitialization(Base, Method)) 4280 return true; 4281 4282 // No concerns about early exits now. 4283 BasePtr.take(); 4284 4285 // Build the operator call. 4286 Expr *FnExpr = new (Context) DeclRefExpr(Method, Method->getType(), 4287 SourceLocation()); 4288 UsualUnaryConversions(FnExpr); 4289 Base = new (Context) CXXOperatorCallExpr(Context, OO_Arrow, FnExpr, &Base, 1, 4290 Method->getResultType().getNonReferenceType(), 4291 OpLoc); 4292 return ActOnMemberReferenceExpr(S, ExprArg(*this, Base), OpLoc, tok::arrow, 4293 MemberLoc, Member, DeclPtrTy()).release(); 4294} 4295 4296/// FixOverloadedFunctionReference - E is an expression that refers to 4297/// a C++ overloaded function (possibly with some parentheses and 4298/// perhaps a '&' around it). We have resolved the overloaded function 4299/// to the function declaration Fn, so patch up the expression E to 4300/// refer (possibly indirectly) to Fn. 4301void Sema::FixOverloadedFunctionReference(Expr *E, FunctionDecl *Fn) { 4302 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) { 4303 FixOverloadedFunctionReference(PE->getSubExpr(), Fn); 4304 E->setType(PE->getSubExpr()->getType()); 4305 } else if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) { 4306 assert(UnOp->getOpcode() == UnaryOperator::AddrOf && 4307 "Can only take the address of an overloaded function"); 4308 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) { 4309 if (Method->isStatic()) { 4310 // Do nothing: static member functions aren't any different 4311 // from non-member functions. 4312 } 4313 else if (QualifiedDeclRefExpr *DRE 4314 = dyn_cast<QualifiedDeclRefExpr>(UnOp->getSubExpr())) { 4315 // We have taken the address of a pointer to member 4316 // function. Perform the computation here so that we get the 4317 // appropriate pointer to member type. 4318 DRE->setDecl(Fn); 4319 DRE->setType(Fn->getType()); 4320 QualType ClassType 4321 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext())); 4322 E->setType(Context.getMemberPointerType(Fn->getType(), 4323 ClassType.getTypePtr())); 4324 return; 4325 } 4326 } 4327 FixOverloadedFunctionReference(UnOp->getSubExpr(), Fn); 4328 E->setType(Context.getPointerType(UnOp->getSubExpr()->getType())); 4329 } else if (DeclRefExpr *DR = dyn_cast<DeclRefExpr>(E)) { 4330 assert(isa<OverloadedFunctionDecl>(DR->getDecl()) && 4331 "Expected overloaded function"); 4332 DR->setDecl(Fn); 4333 E->setType(Fn->getType()); 4334 } else if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(E)) { 4335 MemExpr->setMemberDecl(Fn); 4336 E->setType(Fn->getType()); 4337 } else { 4338 assert(false && "Invalid reference to overloaded function"); 4339 } 4340} 4341 4342} // end namespace clang 4343