Initialization.h revision 6cd03dbb310f472b14b8d6d69d8c9b5b7f1200e2
1//===--- SemaInit.h - Semantic Analysis for Initializers --------*- 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 supporting data types for initialization of objects. 11// 12//===----------------------------------------------------------------------===// 13#ifndef LLVM_CLANG_SEMA_INITIALIZATION_H 14#define LLVM_CLANG_SEMA_INITIALIZATION_H 15 16#include "clang/Sema/Ownership.h" 17#include "clang/Sema/Overload.h" 18#include "clang/AST/Type.h" 19#include "clang/AST/UnresolvedSet.h" 20#include "clang/Basic/SourceLocation.h" 21#include "llvm/ADT/PointerIntPair.h" 22#include "llvm/ADT/SmallVector.h" 23#include <cassert> 24 25namespace clang { 26 27class CXXBaseSpecifier; 28class DeclaratorDecl; 29class DeclaratorInfo; 30class FieldDecl; 31class FunctionDecl; 32class ParmVarDecl; 33class Sema; 34class TypeLoc; 35class VarDecl; 36 37/// \brief Describes an entity that is being initialized. 38class InitializedEntity { 39public: 40 /// \brief Specifies the kind of entity being initialized. 41 enum EntityKind { 42 /// \brief The entity being initialized is a variable. 43 EK_Variable, 44 /// \brief The entity being initialized is a function parameter. 45 EK_Parameter, 46 /// \brief The entity being initialized is the result of a function call. 47 EK_Result, 48 /// \brief The entity being initialized is an exception object that 49 /// is being thrown. 50 EK_Exception, 51 /// \brief The entity being initialized is a non-static data member 52 /// subobject. 53 EK_Member, 54 /// \brief The entity being initialized is an element of an array. 55 EK_ArrayElement, 56 /// \brief The entity being initialized is an object (or array of 57 /// objects) allocated via new. 58 EK_New, 59 /// \brief The entity being initialized is a temporary object. 60 EK_Temporary, 61 /// \brief The entity being initialized is a base member subobject. 62 EK_Base, 63 /// \brief The initialization is being done by a delegating constructor. 64 EK_Delegating, 65 /// \brief The entity being initialized is an element of a vector. 66 /// or vector. 67 EK_VectorElement, 68 /// \brief The entity being initialized is a field of block descriptor for 69 /// the copied-in c++ object. 70 EK_BlockElement, 71 /// \brief The entity being initialized is the real or imaginary part of a 72 /// complex number. 73 EK_ComplexElement 74 }; 75 76private: 77 /// \brief The kind of entity being initialized. 78 EntityKind Kind; 79 80 /// \brief If non-NULL, the parent entity in which this 81 /// initialization occurs. 82 const InitializedEntity *Parent; 83 84 /// \brief The type of the object or reference being initialized. 85 QualType Type; 86 87 union { 88 /// \brief When Kind == EK_Variable or EK_Member, the VarDecl or 89 /// FieldDecl, respectively. 90 DeclaratorDecl *VariableOrMember; 91 92 /// \brief When Kind == EK_Parameter, the ParmVarDecl, with the 93 /// low bit indicating whether the parameter is "consumed". 94 uintptr_t Parameter; 95 96 /// \brief When Kind == EK_Temporary, the type source information for 97 /// the temporary. 98 TypeSourceInfo *TypeInfo; 99 100 struct { 101 /// \brief When Kind == EK_Result, EK_Exception, or EK_New, the 102 /// location of the 'return', 'throw', or 'new' keyword, 103 /// respectively. When Kind == EK_Temporary, the location where 104 /// the temporary is being created. 105 unsigned Location; 106 107 /// \brief Whether the entity being initialized may end up using the 108 /// named return value optimization (NRVO). 109 bool NRVO; 110 } LocAndNRVO; 111 112 /// \brief When Kind == EK_Base, the base specifier that provides the 113 /// base class. The lower bit specifies whether the base is an inherited 114 /// virtual base. 115 uintptr_t Base; 116 117 /// \brief When Kind == EK_ArrayElement, EK_VectorElement, or 118 /// EK_ComplexElement, the index of the array or vector element being 119 /// initialized. 120 unsigned Index; 121 }; 122 123 InitializedEntity() { } 124 125 /// \brief Create the initialization entity for a variable. 126 InitializedEntity(VarDecl *Var) 127 : Kind(EK_Variable), Parent(0), Type(Var->getType()), 128 VariableOrMember(Var) { } 129 130 /// \brief Create the initialization entity for the result of a 131 /// function, throwing an object, performing an explicit cast, or 132 /// initializing a parameter for which there is no declaration. 133 InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type, 134 bool NRVO = false) 135 : Kind(Kind), Parent(0), Type(Type) 136 { 137 LocAndNRVO.Location = Loc.getRawEncoding(); 138 LocAndNRVO.NRVO = NRVO; 139 } 140 141 /// \brief Create the initialization entity for a member subobject. 142 InitializedEntity(FieldDecl *Member, const InitializedEntity *Parent) 143 : Kind(EK_Member), Parent(Parent), Type(Member->getType()), 144 VariableOrMember(Member) { } 145 146 /// \brief Create the initialization entity for an array element. 147 InitializedEntity(ASTContext &Context, unsigned Index, 148 const InitializedEntity &Parent); 149 150public: 151 /// \brief Create the initialization entity for a variable. 152 static InitializedEntity InitializeVariable(VarDecl *Var) { 153 return InitializedEntity(Var); 154 } 155 156 /// \brief Create the initialization entity for a parameter. 157 static InitializedEntity InitializeParameter(ASTContext &Context, 158 ParmVarDecl *Parm) { 159 bool Consumed = (Context.getLangOptions().ObjCAutoRefCount && 160 Parm->hasAttr<NSConsumedAttr>()); 161 162 InitializedEntity Entity; 163 Entity.Kind = EK_Parameter; 164 Entity.Type = Context.getVariableArrayDecayedType( 165 Parm->getType().getUnqualifiedType()); 166 Entity.Parent = 0; 167 Entity.Parameter 168 = (static_cast<uintptr_t>(Consumed) | reinterpret_cast<uintptr_t>(Parm)); 169 return Entity; 170 } 171 172 /// \brief Create the initialization entity for a parameter that is 173 /// only known by its type. 174 static InitializedEntity InitializeParameter(ASTContext &Context, 175 QualType Type, 176 bool Consumed) { 177 InitializedEntity Entity; 178 Entity.Kind = EK_Parameter; 179 Entity.Type = Context.getVariableArrayDecayedType(Type); 180 Entity.Parent = 0; 181 Entity.Parameter = (Consumed); 182 return Entity; 183 } 184 185 /// \brief Create the initialization entity for the result of a function. 186 static InitializedEntity InitializeResult(SourceLocation ReturnLoc, 187 QualType Type, bool NRVO) { 188 return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO); 189 } 190 191 static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc, 192 QualType Type, bool NRVO) { 193 return InitializedEntity(EK_BlockElement, BlockVarLoc, Type, NRVO); 194 } 195 196 /// \brief Create the initialization entity for an exception object. 197 static InitializedEntity InitializeException(SourceLocation ThrowLoc, 198 QualType Type, bool NRVO) { 199 return InitializedEntity(EK_Exception, ThrowLoc, Type, NRVO); 200 } 201 202 /// \brief Create the initialization entity for an object allocated via new. 203 static InitializedEntity InitializeNew(SourceLocation NewLoc, QualType Type) { 204 return InitializedEntity(EK_New, NewLoc, Type); 205 } 206 207 /// \brief Create the initialization entity for a temporary. 208 static InitializedEntity InitializeTemporary(QualType Type) { 209 return InitializedEntity(EK_Temporary, SourceLocation(), Type); 210 } 211 212 /// \brief Create the initialization entity for a temporary. 213 static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo) { 214 InitializedEntity Result(EK_Temporary, SourceLocation(), 215 TypeInfo->getType()); 216 Result.TypeInfo = TypeInfo; 217 return Result; 218 } 219 220 /// \brief Create the initialization entity for a base class subobject. 221 static InitializedEntity InitializeBase(ASTContext &Context, 222 CXXBaseSpecifier *Base, 223 bool IsInheritedVirtualBase); 224 225 /// \brief Create the initialization entity for a delegated constructor. 226 static InitializedEntity InitializeDelegation(QualType Type) { 227 return InitializedEntity(EK_Delegating, SourceLocation(), Type); 228 } 229 230 /// \brief Create the initialization entity for a member subobject. 231 static InitializedEntity InitializeMember(FieldDecl *Member, 232 const InitializedEntity *Parent = 0) { 233 return InitializedEntity(Member, Parent); 234 } 235 236 /// \brief Create the initialization entity for a member subobject. 237 static InitializedEntity InitializeMember(IndirectFieldDecl *Member, 238 const InitializedEntity *Parent = 0) { 239 return InitializedEntity(Member->getAnonField(), Parent); 240 } 241 242 /// \brief Create the initialization entity for an array element. 243 static InitializedEntity InitializeElement(ASTContext &Context, 244 unsigned Index, 245 const InitializedEntity &Parent) { 246 return InitializedEntity(Context, Index, Parent); 247 } 248 249 /// \brief Determine the kind of initialization. 250 EntityKind getKind() const { return Kind; } 251 252 /// \brief Retrieve the parent of the entity being initialized, when 253 /// the initialization itself is occurring within the context of a 254 /// larger initialization. 255 const InitializedEntity *getParent() const { return Parent; } 256 257 /// \brief Retrieve type being initialized. 258 QualType getType() const { return Type; } 259 260 /// \brief Retrieve complete type-source information for the object being 261 /// constructed, if known. 262 TypeSourceInfo *getTypeSourceInfo() const { 263 if (Kind == EK_Temporary) 264 return TypeInfo; 265 266 return 0; 267 } 268 269 /// \brief Retrieve the name of the entity being initialized. 270 DeclarationName getName() const; 271 272 /// \brief Retrieve the variable, parameter, or field being 273 /// initialized. 274 DeclaratorDecl *getDecl() const; 275 276 /// \brief Determine whether this initialization allows the named return 277 /// value optimization, which also applies to thrown objects. 278 bool allowsNRVO() const; 279 280 /// \brief Determine whether this initialization consumes the 281 /// parameter. 282 bool isParameterConsumed() const { 283 assert(getKind() == EK_Parameter && "Not a parameter"); 284 return (Parameter & 1); 285 } 286 287 /// \brief Retrieve the base specifier. 288 CXXBaseSpecifier *getBaseSpecifier() const { 289 assert(getKind() == EK_Base && "Not a base specifier"); 290 return reinterpret_cast<CXXBaseSpecifier *>(Base & ~0x1); 291 } 292 293 /// \brief Return whether the base is an inherited virtual base. 294 bool isInheritedVirtualBase() const { 295 assert(getKind() == EK_Base && "Not a base specifier"); 296 return Base & 0x1; 297 } 298 299 /// \brief Determine the location of the 'return' keyword when initializing 300 /// the result of a function call. 301 SourceLocation getReturnLoc() const { 302 assert(getKind() == EK_Result && "No 'return' location!"); 303 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location); 304 } 305 306 /// \brief Determine the location of the 'throw' keyword when initializing 307 /// an exception object. 308 SourceLocation getThrowLoc() const { 309 assert(getKind() == EK_Exception && "No 'throw' location!"); 310 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location); 311 } 312 313 /// \brief If this is already the initializer for an array or vector 314 /// element, sets the element index. 315 void setElementIndex(unsigned Index) { 316 assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement || 317 EK_ComplexElement); 318 this->Index = Index; 319 } 320}; 321 322/// \brief Describes the kind of initialization being performed, along with 323/// location information for tokens related to the initialization (equal sign, 324/// parentheses). 325class InitializationKind { 326public: 327 /// \brief The kind of initialization being performed. 328 enum InitKind { 329 IK_Direct, ///< Direct initialization 330 IK_Copy, ///< Copy initialization 331 IK_Default, ///< Default initialization 332 IK_Value ///< Value initialization 333 }; 334 335private: 336 /// \brief The kind of initialization that we're storing. 337 enum StoredInitKind { 338 SIK_Direct = IK_Direct, ///< Direct initialization 339 SIK_Copy = IK_Copy, ///< Copy initialization 340 SIK_Default = IK_Default, ///< Default initialization 341 SIK_Value = IK_Value, ///< Value initialization 342 SIK_ImplicitValue, ///< Implicit value initialization 343 SIK_DirectCast, ///< Direct initialization due to a cast 344 /// \brief Direct initialization due to a C-style cast. 345 SIK_DirectCStyleCast, 346 /// \brief Direct initialization due to a functional-style cast. 347 SIK_DirectFunctionalCast 348 }; 349 350 /// \brief The kind of initialization being performed. 351 StoredInitKind Kind; 352 353 /// \brief The source locations involved in the initialization. 354 SourceLocation Locations[3]; 355 356 InitializationKind(StoredInitKind Kind, SourceLocation Loc1, 357 SourceLocation Loc2, SourceLocation Loc3) 358 : Kind(Kind) 359 { 360 Locations[0] = Loc1; 361 Locations[1] = Loc2; 362 Locations[2] = Loc3; 363 } 364 365public: 366 /// \brief Create a direct initialization. 367 static InitializationKind CreateDirect(SourceLocation InitLoc, 368 SourceLocation LParenLoc, 369 SourceLocation RParenLoc) { 370 return InitializationKind(SIK_Direct, InitLoc, LParenLoc, RParenLoc); 371 } 372 373 /// \brief Create a direct initialization due to a cast that isn't a C-style 374 /// or functional cast. 375 static InitializationKind CreateCast(SourceRange TypeRange) { 376 return InitializationKind(SIK_DirectCast, 377 TypeRange.getBegin(), TypeRange.getBegin(), 378 TypeRange.getEnd()); 379 } 380 381 /// \brief Create a direct initialization for a C-style cast. 382 static InitializationKind CreateCStyleCast(SourceLocation StartLoc, 383 SourceRange TypeRange) { 384 return InitializationKind(SIK_DirectCStyleCast, 385 StartLoc, TypeRange.getBegin(), 386 TypeRange.getEnd()); 387 } 388 389 /// \brief Create a direct initialization for a functional cast. 390 static InitializationKind CreateFunctionalCast(SourceRange TypeRange) { 391 return InitializationKind(SIK_DirectFunctionalCast, 392 TypeRange.getBegin(), TypeRange.getBegin(), 393 TypeRange.getEnd()); 394 } 395 396 /// \brief Create a copy initialization. 397 static InitializationKind CreateCopy(SourceLocation InitLoc, 398 SourceLocation EqualLoc) { 399 return InitializationKind(SIK_Copy, InitLoc, EqualLoc, EqualLoc); 400 } 401 402 /// \brief Create a default initialization. 403 static InitializationKind CreateDefault(SourceLocation InitLoc) { 404 return InitializationKind(SIK_Default, InitLoc, InitLoc, InitLoc); 405 } 406 407 /// \brief Create a value initialization. 408 static InitializationKind CreateValue(SourceLocation InitLoc, 409 SourceLocation LParenLoc, 410 SourceLocation RParenLoc, 411 bool isImplicit = false) { 412 return InitializationKind(isImplicit? SIK_ImplicitValue : SIK_Value, 413 InitLoc, LParenLoc, RParenLoc); 414 } 415 416 /// \brief Determine the initialization kind. 417 InitKind getKind() const { 418 if (Kind > SIK_ImplicitValue) 419 return IK_Direct; 420 if (Kind == SIK_ImplicitValue) 421 return IK_Value; 422 423 return (InitKind)Kind; 424 } 425 426 /// \brief Determine whether this initialization is an explicit cast. 427 bool isExplicitCast() const { 428 return Kind == SIK_DirectCast || 429 Kind == SIK_DirectCStyleCast || 430 Kind == SIK_DirectFunctionalCast; 431 } 432 433 /// \brief Determine whether this initialization is a C-style cast. 434 bool isCStyleOrFunctionalCast() const { 435 return Kind == SIK_DirectCStyleCast || Kind == SIK_DirectFunctionalCast; 436 } 437 438 /// brief Determine whether this is a C-style cast. 439 bool isCStyleCast() const { 440 return Kind == SIK_DirectCStyleCast; 441 } 442 443 /// brief Determine whether this is a functional-style cast. 444 bool isFunctionalCast() const { 445 return Kind == SIK_DirectFunctionalCast; 446 } 447 448 /// \brief Determine whether this initialization is an implicit 449 /// value-initialization, e.g., as occurs during aggregate 450 /// initialization. 451 bool isImplicitValueInit() const { return Kind == SIK_ImplicitValue; } 452 453 /// \brief Retrieve the location at which initialization is occurring. 454 SourceLocation getLocation() const { return Locations[0]; } 455 456 /// \brief Retrieve the source range that covers the initialization. 457 SourceRange getRange() const { 458 return SourceRange(Locations[0], Locations[2]); 459 } 460 461 /// \brief Retrieve the location of the equal sign for copy initialization 462 /// (if present). 463 SourceLocation getEqualLoc() const { 464 assert(Kind == SIK_Copy && "Only copy initialization has an '='"); 465 return Locations[1]; 466 } 467 468 bool isCopyInit() const { return Kind == SIK_Copy; } 469 470 /// \brief Retrieve the source range containing the locations of the open 471 /// and closing parentheses for value and direct initializations. 472 SourceRange getParenRange() const { 473 assert((getKind() == IK_Direct || Kind == SIK_Value) && 474 "Only direct- and value-initialization have parentheses"); 475 return SourceRange(Locations[1], Locations[2]); 476 } 477}; 478 479/// \brief Describes the sequence of initializations required to initialize 480/// a given object or reference with a set of arguments. 481class InitializationSequence { 482public: 483 /// \brief Describes the kind of initialization sequence computed. 484 enum SequenceKind { 485 /// \brief A failed initialization sequence. The failure kind tells what 486 /// happened. 487 FailedSequence = 0, 488 489 /// \brief A dependent initialization, which could not be 490 /// type-checked due to the presence of dependent types or 491 /// dependently-typed expressions. 492 DependentSequence, 493 494 /// \brief A normal sequence. 495 NormalSequence 496 }; 497 498 /// \brief Describes the kind of a particular step in an initialization 499 /// sequence. 500 enum StepKind { 501 /// \brief Resolve the address of an overloaded function to a specific 502 /// function declaration. 503 SK_ResolveAddressOfOverloadedFunction, 504 /// \brief Perform a derived-to-base cast, producing an rvalue. 505 SK_CastDerivedToBaseRValue, 506 /// \brief Perform a derived-to-base cast, producing an xvalue. 507 SK_CastDerivedToBaseXValue, 508 /// \brief Perform a derived-to-base cast, producing an lvalue. 509 SK_CastDerivedToBaseLValue, 510 /// \brief Reference binding to an lvalue. 511 SK_BindReference, 512 /// \brief Reference binding to a temporary. 513 SK_BindReferenceToTemporary, 514 /// \brief An optional copy of a temporary object to another 515 /// temporary object, which is permitted (but not required) by 516 /// C++98/03 but not C++0x. 517 SK_ExtraneousCopyToTemporary, 518 /// \brief Perform a user-defined conversion, either via a conversion 519 /// function or via a constructor. 520 SK_UserConversion, 521 /// \brief Perform a qualification conversion, producing an rvalue. 522 SK_QualificationConversionRValue, 523 /// \brief Perform a qualification conversion, producing an xvalue. 524 SK_QualificationConversionXValue, 525 /// \brief Perform a qualification conversion, producing an lvalue. 526 SK_QualificationConversionLValue, 527 /// \brief Perform an implicit conversion sequence. 528 SK_ConversionSequence, 529 /// \brief Perform list-initialization without a constructor 530 SK_ListInitialization, 531 /// \brief Perform list-initialization with a constructor. 532 SK_ListConstructorCall, 533 /// \brief Unwrap the single-element initializer list for a reference. 534 SK_UnwrapInitList, 535 /// \brief Rewrap the single-element initializer list for a reference. 536 SK_RewrapInitList, 537 /// \brief Perform initialization via a constructor. 538 SK_ConstructorInitialization, 539 /// \brief Zero-initialize the object 540 SK_ZeroInitialization, 541 /// \brief C assignment 542 SK_CAssignment, 543 /// \brief Initialization by string 544 SK_StringInit, 545 /// \brief An initialization that "converts" an Objective-C object 546 /// (not a point to an object) to another Objective-C object type. 547 SK_ObjCObjectConversion, 548 /// \brief Array initialization (from an array rvalue). 549 /// This is a GNU C extension. 550 SK_ArrayInit, 551 /// \brief Pass an object by indirect copy-and-restore. 552 SK_PassByIndirectCopyRestore, 553 /// \brief Pass an object by indirect restore. 554 SK_PassByIndirectRestore, 555 /// \brief Produce an Objective-C object pointer. 556 SK_ProduceObjCObject, 557 /// \brief Construct a std::initializer_list from an initializer list. 558 SK_StdInitializerList 559 }; 560 561 /// \brief A single step in the initialization sequence. 562 class Step { 563 public: 564 /// \brief The kind of conversion or initialization step we are taking. 565 StepKind Kind; 566 567 // \brief The type that results from this initialization. 568 QualType Type; 569 570 union { 571 /// \brief When Kind == SK_ResolvedOverloadedFunction or Kind == 572 /// SK_UserConversion, the function that the expression should be 573 /// resolved to or the conversion function to call, respectively. 574 /// When Kind == SK_ConstructorInitialization or SK_ListConstruction, 575 /// the constructor to be called. 576 /// 577 /// Always a FunctionDecl, plus a Boolean flag telling if it was 578 /// selected from an overloaded set having size greater than 1. 579 /// For conversion decls, the naming class is the source type. 580 /// For construct decls, the naming class is the target type. 581 struct { 582 bool HadMultipleCandidates; 583 FunctionDecl *Function; 584 DeclAccessPair FoundDecl; 585 } Function; 586 587 /// \brief When Kind = SK_ConversionSequence, the implicit conversion 588 /// sequence. 589 ImplicitConversionSequence *ICS; 590 591 /// \brief When Kind = SK_RewrapInitList, the syntactic form of the 592 /// wrapping list. 593 InitListExpr *WrappingSyntacticList; 594 }; 595 596 void Destroy(); 597 }; 598 599private: 600 /// \brief The kind of initialization sequence computed. 601 enum SequenceKind SequenceKind; 602 603 /// \brief Steps taken by this initialization. 604 SmallVector<Step, 4> Steps; 605 606public: 607 /// \brief Describes why initialization failed. 608 enum FailureKind { 609 /// \brief Too many initializers provided for a reference. 610 FK_TooManyInitsForReference, 611 /// \brief Array must be initialized with an initializer list. 612 FK_ArrayNeedsInitList, 613 /// \brief Array must be initialized with an initializer list or a 614 /// string literal. 615 FK_ArrayNeedsInitListOrStringLiteral, 616 /// \brief Array type mismatch. 617 FK_ArrayTypeMismatch, 618 /// \brief Non-constant array initializer 619 FK_NonConstantArrayInit, 620 /// \brief Cannot resolve the address of an overloaded function. 621 FK_AddressOfOverloadFailed, 622 /// \brief Overloading due to reference initialization failed. 623 FK_ReferenceInitOverloadFailed, 624 /// \brief Non-const lvalue reference binding to a temporary. 625 FK_NonConstLValueReferenceBindingToTemporary, 626 /// \brief Non-const lvalue reference binding to an lvalue of unrelated 627 /// type. 628 FK_NonConstLValueReferenceBindingToUnrelated, 629 /// \brief Rvalue reference binding to an lvalue. 630 FK_RValueReferenceBindingToLValue, 631 /// \brief Reference binding drops qualifiers. 632 FK_ReferenceInitDropsQualifiers, 633 /// \brief Reference binding failed. 634 FK_ReferenceInitFailed, 635 /// \brief Implicit conversion failed. 636 FK_ConversionFailed, 637 /// \brief Implicit conversion failed. 638 FK_ConversionFromPropertyFailed, 639 /// \brief Too many initializers for scalar 640 FK_TooManyInitsForScalar, 641 /// \brief Reference initialization from an initializer list 642 FK_ReferenceBindingToInitList, 643 /// \brief Initialization of some unused destination type with an 644 /// initializer list. 645 FK_InitListBadDestinationType, 646 /// \brief Overloading for a user-defined conversion failed. 647 FK_UserConversionOverloadFailed, 648 /// \brief Overloading for initialization by constructor failed. 649 FK_ConstructorOverloadFailed, 650 /// \brief Overloading for list-initialization by constructor failed. 651 FK_ListConstructorOverloadFailed, 652 /// \brief Default-initialization of a 'const' object. 653 FK_DefaultInitOfConst, 654 /// \brief Initialization of an incomplete type. 655 FK_Incomplete, 656 /// \brief Variable-length array must not have an initializer. 657 FK_VariableLengthArrayHasInitializer, 658 /// \brief List initialization failed at some point. 659 FK_ListInitializationFailed, 660 /// \brief Initializer has a placeholder type which cannot be 661 /// resolved by initialization. 662 FK_PlaceholderType, 663 /// \brief Failed to initialize a std::initializer_list because copy 664 /// construction of some element failed. 665 FK_InitListElementCopyFailure 666 }; 667 668private: 669 /// \brief The reason why initialization failed. 670 FailureKind Failure; 671 672 /// \brief The failed result of overload resolution. 673 OverloadingResult FailedOverloadResult; 674 675 /// \brief The candidate set created when initialization failed. 676 OverloadCandidateSet FailedCandidateSet; 677 678 /// \brief Prints a follow-up note that highlights the location of 679 /// the initialized entity, if it's remote. 680 void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity); 681 682public: 683 /// \brief Try to perform initialization of the given entity, creating a 684 /// record of the steps required to perform the initialization. 685 /// 686 /// The generated initialization sequence will either contain enough 687 /// information to diagnose 688 /// 689 /// \param S the semantic analysis object. 690 /// 691 /// \param Entity the entity being initialized. 692 /// 693 /// \param Kind the kind of initialization being performed. 694 /// 695 /// \param Args the argument(s) provided for initialization. 696 /// 697 /// \param NumArgs the number of arguments provided for initialization. 698 InitializationSequence(Sema &S, 699 const InitializedEntity &Entity, 700 const InitializationKind &Kind, 701 Expr **Args, 702 unsigned NumArgs); 703 704 ~InitializationSequence(); 705 706 /// \brief Perform the actual initialization of the given entity based on 707 /// the computed initialization sequence. 708 /// 709 /// \param S the semantic analysis object. 710 /// 711 /// \param Entity the entity being initialized. 712 /// 713 /// \param Kind the kind of initialization being performed. 714 /// 715 /// \param Args the argument(s) provided for initialization, ownership of 716 /// which is transferred into the routine. 717 /// 718 /// \param ResultType if non-NULL, will be set to the type of the 719 /// initialized object, which is the type of the declaration in most 720 /// cases. However, when the initialized object is a variable of 721 /// incomplete array type and the initializer is an initializer 722 /// list, this type will be set to the completed array type. 723 /// 724 /// \returns an expression that performs the actual object initialization, if 725 /// the initialization is well-formed. Otherwise, emits diagnostics 726 /// and returns an invalid expression. 727 ExprResult Perform(Sema &S, 728 const InitializedEntity &Entity, 729 const InitializationKind &Kind, 730 MultiExprArg Args, 731 QualType *ResultType = 0); 732 733 /// \brief Diagnose an potentially-invalid initialization sequence. 734 /// 735 /// \returns true if the initialization sequence was ill-formed, 736 /// false otherwise. 737 bool Diagnose(Sema &S, 738 const InitializedEntity &Entity, 739 const InitializationKind &Kind, 740 Expr **Args, unsigned NumArgs); 741 742 /// \brief Determine the kind of initialization sequence computed. 743 enum SequenceKind getKind() const { return SequenceKind; } 744 745 /// \brief Set the kind of sequence computed. 746 void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; } 747 748 /// \brief Determine whether the initialization sequence is valid. 749 operator bool() const { return !Failed(); } 750 751 /// \brief Determine whether the initialization sequence is invalid. 752 bool Failed() const { return SequenceKind == FailedSequence; } 753 754 typedef SmallVector<Step, 4>::const_iterator step_iterator; 755 step_iterator step_begin() const { return Steps.begin(); } 756 step_iterator step_end() const { return Steps.end(); } 757 758 /// \brief Determine whether this initialization is a direct reference 759 /// binding (C++ [dcl.init.ref]). 760 bool isDirectReferenceBinding() const; 761 762 /// \brief Determine whether this initialization failed due to an ambiguity. 763 bool isAmbiguous() const; 764 765 /// \brief Determine whether this initialization is direct call to a 766 /// constructor. 767 bool isConstructorInitialization() const; 768 769 /// \brief Returns whether the last step in this initialization sequence is a 770 /// narrowing conversion, defined by C++0x [dcl.init.list]p7. 771 /// 772 /// If this function returns true, *isInitializerConstant will be set to 773 /// describe whether *Initializer was a constant expression. If 774 /// *isInitializerConstant is set to true, *ConstantValue will be set to the 775 /// evaluated value of *Initializer. 776 bool endsWithNarrowing(ASTContext &Ctx, const Expr *Initializer, 777 bool *isInitializerConstant, 778 APValue *ConstantValue) const; 779 780 /// \brief Add a new step in the initialization that resolves the address 781 /// of an overloaded function to a specific function declaration. 782 /// 783 /// \param Function the function to which the overloaded function reference 784 /// resolves. 785 void AddAddressOverloadResolutionStep(FunctionDecl *Function, 786 DeclAccessPair Found, 787 bool HadMultipleCandidates); 788 789 /// \brief Add a new step in the initialization that performs a derived-to- 790 /// base cast. 791 /// 792 /// \param BaseType the base type to which we will be casting. 793 /// 794 /// \param IsLValue true if the result of this cast will be treated as 795 /// an lvalue. 796 void AddDerivedToBaseCastStep(QualType BaseType, 797 ExprValueKind Category); 798 799 /// \brief Add a new step binding a reference to an object. 800 /// 801 /// \param BindingTemporary True if we are binding a reference to a temporary 802 /// object (thereby extending its lifetime); false if we are binding to an 803 /// lvalue or an lvalue treated as an rvalue. 804 /// 805 /// \param UnnecessaryCopy True if we should check for a copy 806 /// constructor for a completely unnecessary but 807 void AddReferenceBindingStep(QualType T, bool BindingTemporary); 808 809 /// \brief Add a new step that makes an extraneous copy of the input 810 /// to a temporary of the same class type. 811 /// 812 /// This extraneous copy only occurs during reference binding in 813 /// C++98/03, where we are permitted (but not required) to introduce 814 /// an extra copy. At a bare minimum, we must check that we could 815 /// call the copy constructor, and produce a diagnostic if the copy 816 /// constructor is inaccessible or no copy constructor matches. 817 // 818 /// \param T The type of the temporary being created. 819 void AddExtraneousCopyToTemporary(QualType T); 820 821 /// \brief Add a new step invoking a conversion function, which is either 822 /// a constructor or a conversion function. 823 void AddUserConversionStep(FunctionDecl *Function, 824 DeclAccessPair FoundDecl, 825 QualType T, 826 bool HadMultipleCandidates); 827 828 /// \brief Add a new step that performs a qualification conversion to the 829 /// given type. 830 void AddQualificationConversionStep(QualType Ty, 831 ExprValueKind Category); 832 833 /// \brief Add a new step that applies an implicit conversion sequence. 834 void AddConversionSequenceStep(const ImplicitConversionSequence &ICS, 835 QualType T); 836 837 /// \brief Add a list-initialization step. 838 void AddListInitializationStep(QualType T); 839 840 /// \brief Add a constructor-initialization step. 841 /// 842 /// \arg FromInitList The constructor call is syntactically an initializer 843 /// list. 844 /// \arg AsInitList The constructor is called as an init list constructor. 845 void AddConstructorInitializationStep(CXXConstructorDecl *Constructor, 846 AccessSpecifier Access, 847 QualType T, 848 bool HadMultipleCandidates, 849 bool FromInitList, bool AsInitList); 850 851 /// \brief Add a zero-initialization step. 852 void AddZeroInitializationStep(QualType T); 853 854 /// \brief Add a C assignment step. 855 // 856 // FIXME: It isn't clear whether this should ever be needed; 857 // ideally, we would handle everything needed in C in the common 858 // path. However, that isn't the case yet. 859 void AddCAssignmentStep(QualType T); 860 861 /// \brief Add a string init step. 862 void AddStringInitStep(QualType T); 863 864 /// \brief Add an Objective-C object conversion step, which is 865 /// always a no-op. 866 void AddObjCObjectConversionStep(QualType T); 867 868 /// \brief Add an array initialization step. 869 void AddArrayInitStep(QualType T); 870 871 /// \brief Add a step to pass an object by indirect copy-restore. 872 void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy); 873 874 /// \brief Add a step to "produce" an Objective-C object (by 875 /// retaining it). 876 void AddProduceObjCObjectStep(QualType T); 877 878 /// \brief Add a step to construct a std::initializer_list object from an 879 /// initializer list. 880 void AddStdInitializerListConstructionStep(QualType T); 881 882 /// \brief Add steps to unwrap a initializer list for a reference around a 883 /// single element and rewrap it at the end. 884 void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic); 885 886 /// \brief Note that this initialization sequence failed. 887 void SetFailed(FailureKind Failure) { 888 SequenceKind = FailedSequence; 889 this->Failure = Failure; 890 } 891 892 /// \brief Note that this initialization sequence failed due to failed 893 /// overload resolution. 894 void SetOverloadFailure(FailureKind Failure, OverloadingResult Result); 895 896 /// \brief Retrieve a reference to the candidate set when overload 897 /// resolution fails. 898 OverloadCandidateSet &getFailedCandidateSet() { 899 return FailedCandidateSet; 900 } 901 902 /// \brief Get the overloading result, for when the initialization 903 /// sequence failed due to a bad overload. 904 OverloadingResult getFailedOverloadResult() const { 905 return FailedOverloadResult; 906 } 907 908 /// \brief Determine why initialization failed. 909 FailureKind getFailureKind() const { 910 assert(Failed() && "Not an initialization failure!"); 911 return Failure; 912 } 913 914 /// \brief Dump a representation of this initialization sequence to 915 /// the given stream, for debugging purposes. 916 void dump(raw_ostream &OS) const; 917 918 /// \brief Dump a representation of this initialization sequence to 919 /// standard error, for debugging purposes. 920 void dump() const; 921}; 922 923} // end namespace clang 924 925#endif // LLVM_CLANG_SEMA_INITIALIZATION_H 926