Initialization.h revision 0f163e964289bc18e9bc1ec37a6a01018ba62640
1//===--- Initialization.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 /// \brief The entity being initialized is the field that captures a 75 /// variable in a lambda. 76 EK_LambdaCapture 77 }; 78 79private: 80 /// \brief The kind of entity being initialized. 81 EntityKind Kind; 82 83 /// \brief If non-NULL, the parent entity in which this 84 /// initialization occurs. 85 const InitializedEntity *Parent; 86 87 /// \brief The type of the object or reference being initialized. 88 QualType Type; 89 90 union { 91 /// \brief When Kind == EK_Variable, or EK_Member, the VarDecl or 92 /// FieldDecl, respectively. 93 DeclaratorDecl *VariableOrMember; 94 95 /// \brief When Kind == EK_Parameter, the ParmVarDecl, with the 96 /// low bit indicating whether the parameter is "consumed". 97 uintptr_t Parameter; 98 99 /// \brief When Kind == EK_Temporary, the type source information for 100 /// the temporary. 101 TypeSourceInfo *TypeInfo; 102 103 struct { 104 /// \brief When Kind == EK_Result, EK_Exception, EK_New, the 105 /// location of the 'return', 'throw', or 'new' keyword, 106 /// respectively. When Kind == EK_Temporary, the location where 107 /// the temporary is being created. 108 unsigned Location; 109 110 /// \brief Whether the entity being initialized may end up using the 111 /// named return value optimization (NRVO). 112 bool NRVO; 113 } LocAndNRVO; 114 115 /// \brief When Kind == EK_Base, the base specifier that provides the 116 /// base class. The lower bit specifies whether the base is an inherited 117 /// virtual base. 118 uintptr_t Base; 119 120 /// \brief When Kind == EK_ArrayElement, EK_VectorElement, or 121 /// EK_ComplexElement, the index of the array or vector element being 122 /// initialized. 123 unsigned Index; 124 125 struct { 126 /// \brief The variable being captured by an EK_LambdaCapture. 127 VarDecl *Var; 128 129 /// \brief The source location at which the capture occurs. 130 unsigned Location; 131 } Capture; 132 }; 133 134 InitializedEntity() { } 135 136 /// \brief Create the initialization entity for a variable. 137 InitializedEntity(VarDecl *Var) 138 : Kind(EK_Variable), Parent(0), Type(Var->getType()), 139 VariableOrMember(Var) { } 140 141 /// \brief Create the initialization entity for the result of a 142 /// function, throwing an object, performing an explicit cast, or 143 /// initializing a parameter for which there is no declaration. 144 InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type, 145 bool NRVO = false) 146 : Kind(Kind), Parent(0), Type(Type) 147 { 148 LocAndNRVO.Location = Loc.getRawEncoding(); 149 LocAndNRVO.NRVO = NRVO; 150 } 151 152 /// \brief Create the initialization entity for a member subobject. 153 InitializedEntity(FieldDecl *Member, const InitializedEntity *Parent) 154 : Kind(EK_Member), Parent(Parent), Type(Member->getType()), 155 VariableOrMember(Member) { } 156 157 /// \brief Create the initialization entity for an array element. 158 InitializedEntity(ASTContext &Context, unsigned Index, 159 const InitializedEntity &Parent); 160 161 /// \brief Create the initialization entity for a lambda capture. 162 InitializedEntity(VarDecl *Var, FieldDecl *Field, SourceLocation Loc) 163 : Kind(EK_LambdaCapture), Parent(0), Type(Field->getType()) 164 { 165 Capture.Var = Var; 166 Capture.Location = Loc.getRawEncoding(); 167 } 168 169public: 170 /// \brief Create the initialization entity for a variable. 171 static InitializedEntity InitializeVariable(VarDecl *Var) { 172 return InitializedEntity(Var); 173 } 174 175 /// \brief Create the initialization entity for a parameter. 176 static InitializedEntity InitializeParameter(ASTContext &Context, 177 ParmVarDecl *Parm) { 178 bool Consumed = (Context.getLangOptions().ObjCAutoRefCount && 179 Parm->hasAttr<NSConsumedAttr>()); 180 181 InitializedEntity Entity; 182 Entity.Kind = EK_Parameter; 183 Entity.Type = Context.getVariableArrayDecayedType( 184 Parm->getType().getUnqualifiedType()); 185 Entity.Parent = 0; 186 Entity.Parameter 187 = (static_cast<uintptr_t>(Consumed) | reinterpret_cast<uintptr_t>(Parm)); 188 return Entity; 189 } 190 191 /// \brief Create the initialization entity for a parameter that is 192 /// only known by its type. 193 static InitializedEntity InitializeParameter(ASTContext &Context, 194 QualType Type, 195 bool Consumed) { 196 InitializedEntity Entity; 197 Entity.Kind = EK_Parameter; 198 Entity.Type = Context.getVariableArrayDecayedType(Type); 199 Entity.Parent = 0; 200 Entity.Parameter = (Consumed); 201 return Entity; 202 } 203 204 /// \brief Create the initialization entity for the result of a function. 205 static InitializedEntity InitializeResult(SourceLocation ReturnLoc, 206 QualType Type, bool NRVO) { 207 return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO); 208 } 209 210 static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc, 211 QualType Type, bool NRVO) { 212 return InitializedEntity(EK_BlockElement, BlockVarLoc, Type, NRVO); 213 } 214 215 /// \brief Create the initialization entity for an exception object. 216 static InitializedEntity InitializeException(SourceLocation ThrowLoc, 217 QualType Type, bool NRVO) { 218 return InitializedEntity(EK_Exception, ThrowLoc, Type, NRVO); 219 } 220 221 /// \brief Create the initialization entity for an object allocated via new. 222 static InitializedEntity InitializeNew(SourceLocation NewLoc, QualType Type) { 223 return InitializedEntity(EK_New, NewLoc, Type); 224 } 225 226 /// \brief Create the initialization entity for a temporary. 227 static InitializedEntity InitializeTemporary(QualType Type) { 228 return InitializedEntity(EK_Temporary, SourceLocation(), Type); 229 } 230 231 /// \brief Create the initialization entity for a temporary. 232 static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo) { 233 InitializedEntity Result(EK_Temporary, SourceLocation(), 234 TypeInfo->getType()); 235 Result.TypeInfo = TypeInfo; 236 return Result; 237 } 238 239 /// \brief Create the initialization entity for a base class subobject. 240 static InitializedEntity InitializeBase(ASTContext &Context, 241 CXXBaseSpecifier *Base, 242 bool IsInheritedVirtualBase); 243 244 /// \brief Create the initialization entity for a delegated constructor. 245 static InitializedEntity InitializeDelegation(QualType Type) { 246 return InitializedEntity(EK_Delegating, SourceLocation(), Type); 247 } 248 249 /// \brief Create the initialization entity for a member subobject. 250 static InitializedEntity InitializeMember(FieldDecl *Member, 251 const InitializedEntity *Parent = 0) { 252 return InitializedEntity(Member, Parent); 253 } 254 255 /// \brief Create the initialization entity for a member subobject. 256 static InitializedEntity InitializeMember(IndirectFieldDecl *Member, 257 const InitializedEntity *Parent = 0) { 258 return InitializedEntity(Member->getAnonField(), Parent); 259 } 260 261 /// \brief Create the initialization entity for an array element. 262 static InitializedEntity InitializeElement(ASTContext &Context, 263 unsigned Index, 264 const InitializedEntity &Parent) { 265 return InitializedEntity(Context, Index, Parent); 266 } 267 268 /// \brief Create the initialization entity for a lambda capture. 269 static InitializedEntity InitializeLambdaCapture(VarDecl *Var, 270 FieldDecl *Field, 271 SourceLocation Loc) { 272 return InitializedEntity(Var, Field, Loc); 273 } 274 275 /// \brief Determine the kind of initialization. 276 EntityKind getKind() const { return Kind; } 277 278 /// \brief Retrieve the parent of the entity being initialized, when 279 /// the initialization itself is occurring within the context of a 280 /// larger initialization. 281 const InitializedEntity *getParent() const { return Parent; } 282 283 /// \brief Retrieve type being initialized. 284 QualType getType() const { return Type; } 285 286 /// \brief Retrieve complete type-source information for the object being 287 /// constructed, if known. 288 TypeSourceInfo *getTypeSourceInfo() const { 289 if (Kind == EK_Temporary) 290 return TypeInfo; 291 292 return 0; 293 } 294 295 /// \brief Retrieve the name of the entity being initialized. 296 DeclarationName getName() const; 297 298 /// \brief Retrieve the variable, parameter, or field being 299 /// initialized. 300 DeclaratorDecl *getDecl() const; 301 302 /// \brief Determine whether this initialization allows the named return 303 /// value optimization, which also applies to thrown objects. 304 bool allowsNRVO() const; 305 306 /// \brief Determine whether this initialization consumes the 307 /// parameter. 308 bool isParameterConsumed() const { 309 assert(getKind() == EK_Parameter && "Not a parameter"); 310 return (Parameter & 1); 311 } 312 313 /// \brief Retrieve the base specifier. 314 CXXBaseSpecifier *getBaseSpecifier() const { 315 assert(getKind() == EK_Base && "Not a base specifier"); 316 return reinterpret_cast<CXXBaseSpecifier *>(Base & ~0x1); 317 } 318 319 /// \brief Return whether the base is an inherited virtual base. 320 bool isInheritedVirtualBase() const { 321 assert(getKind() == EK_Base && "Not a base specifier"); 322 return Base & 0x1; 323 } 324 325 /// \brief Determine the location of the 'return' keyword when initializing 326 /// the result of a function call. 327 SourceLocation getReturnLoc() const { 328 assert(getKind() == EK_Result && "No 'return' location!"); 329 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location); 330 } 331 332 /// \brief Determine the location of the 'throw' keyword when initializing 333 /// an exception object. 334 SourceLocation getThrowLoc() const { 335 assert(getKind() == EK_Exception && "No 'throw' location!"); 336 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location); 337 } 338 339 /// \brief If this is already the initializer for an array or vector 340 /// element, sets the element index. 341 void setElementIndex(unsigned Index) { 342 assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement || 343 EK_ComplexElement); 344 this->Index = Index; 345 } 346 347 /// \brief Retrieve the variable for a captured variable in a lambda. 348 VarDecl *getCapturedVar() const { 349 assert(getKind() == EK_LambdaCapture && "Not a lambda capture!"); 350 return Capture.Var; 351 } 352 353 /// \brief Determine the location of the capture when initializing 354 /// field from a captured variable in a lambda. 355 SourceLocation getCaptureLoc() const { 356 assert(getKind() == EK_LambdaCapture && "Not a lambda capture!"); 357 return SourceLocation::getFromRawEncoding(Capture.Location); 358 } 359}; 360 361/// \brief Describes the kind of initialization being performed, along with 362/// location information for tokens related to the initialization (equal sign, 363/// parentheses). 364class InitializationKind { 365public: 366 /// \brief The kind of initialization being performed. 367 enum InitKind { 368 IK_Direct, ///< Direct initialization 369 IK_DirectList, ///< Direct list-initialization 370 IK_Copy, ///< Copy initialization 371 IK_Default, ///< Default initialization 372 IK_Value ///< Value initialization 373 }; 374 375private: 376 /// \brief The context of the initialization. 377 enum InitContext { 378 IC_Normal, ///< Normal context 379 IC_Implicit, ///< Implicit context (value initialization) 380 IC_StaticCast, ///< Static cast context 381 IC_CStyleCast, ///< C-style cast context 382 IC_FunctionalCast ///< Functional cast context 383 }; 384 385 /// \brief The kind of initialization being performed. 386 InitKind Kind : 8; 387 388 /// \brief The context of the initialization. 389 InitContext Context : 8; 390 391 /// \brief The source locations involved in the initialization. 392 SourceLocation Locations[3]; 393 394 InitializationKind(InitKind Kind, InitContext Context, SourceLocation Loc1, 395 SourceLocation Loc2, SourceLocation Loc3) 396 : Kind(Kind), Context(Context) 397 { 398 Locations[0] = Loc1; 399 Locations[1] = Loc2; 400 Locations[2] = Loc3; 401 } 402 403public: 404 /// \brief Create a direct initialization. 405 static InitializationKind CreateDirect(SourceLocation InitLoc, 406 SourceLocation LParenLoc, 407 SourceLocation RParenLoc) { 408 return InitializationKind(IK_Direct, IC_Normal, 409 InitLoc, LParenLoc, RParenLoc); 410 } 411 412 static InitializationKind CreateDirectList(SourceLocation InitLoc) { 413 return InitializationKind(IK_DirectList, IC_Normal, 414 InitLoc, InitLoc, InitLoc); 415 } 416 417 /// \brief Create a direct initialization due to a cast that isn't a C-style 418 /// or functional cast. 419 static InitializationKind CreateCast(SourceRange TypeRange) { 420 return InitializationKind(IK_Direct, IC_StaticCast, TypeRange.getBegin(), 421 TypeRange.getBegin(), TypeRange.getEnd()); 422 } 423 424 /// \brief Create a direct initialization for a C-style cast. 425 static InitializationKind CreateCStyleCast(SourceLocation StartLoc, 426 SourceRange TypeRange, 427 bool InitList) { 428 // C++ cast syntax doesn't permit init lists, but C compound literals are 429 // exactly that. 430 return InitializationKind(InitList ? IK_DirectList : IK_Direct, 431 IC_CStyleCast, StartLoc, TypeRange.getBegin(), 432 TypeRange.getEnd()); 433 } 434 435 /// \brief Create a direct initialization for a functional cast. 436 static InitializationKind CreateFunctionalCast(SourceRange TypeRange, 437 bool InitList) { 438 return InitializationKind(InitList ? IK_DirectList : IK_Direct, 439 IC_FunctionalCast, TypeRange.getBegin(), 440 TypeRange.getBegin(), TypeRange.getEnd()); 441 } 442 443 /// \brief Create a copy initialization. 444 static InitializationKind CreateCopy(SourceLocation InitLoc, 445 SourceLocation EqualLoc) { 446 return InitializationKind(IK_Copy, IC_Normal, InitLoc, EqualLoc, EqualLoc); 447 } 448 449 /// \brief Create a default initialization. 450 static InitializationKind CreateDefault(SourceLocation InitLoc) { 451 return InitializationKind(IK_Default, IC_Normal, InitLoc, InitLoc, InitLoc); 452 } 453 454 /// \brief Create a value initialization. 455 static InitializationKind CreateValue(SourceLocation InitLoc, 456 SourceLocation LParenLoc, 457 SourceLocation RParenLoc, 458 bool isImplicit = false) { 459 return InitializationKind(IK_Value, isImplicit ? IC_Implicit : IC_Normal, 460 InitLoc, LParenLoc, RParenLoc); 461 } 462 463 /// \brief Determine the initialization kind. 464 InitKind getKind() const { 465 return Kind; 466 } 467 468 /// \brief Determine whether this initialization is an explicit cast. 469 bool isExplicitCast() const { 470 return Context >= IC_StaticCast; 471 } 472 473 /// \brief Determine whether this initialization is a C-style cast. 474 bool isCStyleOrFunctionalCast() const { 475 return Context >= IC_CStyleCast; 476 } 477 478 /// \brief Determine whether this is a C-style cast. 479 bool isCStyleCast() const { 480 return Context == IC_CStyleCast; 481 } 482 483 /// \brief Determine whether this is a functional-style cast. 484 bool isFunctionalCast() const { 485 return Context == IC_FunctionalCast; 486 } 487 488 /// \brief Determine whether this initialization is an implicit 489 /// value-initialization, e.g., as occurs during aggregate 490 /// initialization. 491 bool isImplicitValueInit() const { return Context == IC_Implicit; } 492 493 /// \brief Retrieve the location at which initialization is occurring. 494 SourceLocation getLocation() const { return Locations[0]; } 495 496 /// \brief Retrieve the source range that covers the initialization. 497 SourceRange getRange() const { 498 return SourceRange(Locations[0], Locations[2]); 499 } 500 501 /// \brief Retrieve the location of the equal sign for copy initialization 502 /// (if present). 503 SourceLocation getEqualLoc() const { 504 assert(Kind == IK_Copy && "Only copy initialization has an '='"); 505 return Locations[1]; 506 } 507 508 bool isCopyInit() const { return Kind == IK_Copy; } 509 510 /// \brief Retrieve whether this initialization allows the use of explicit 511 /// constructors. 512 bool AllowExplicit() const { return !isCopyInit(); } 513 514 /// \brief Retrieve the source range containing the locations of the open 515 /// and closing parentheses for value and direct initializations. 516 SourceRange getParenRange() const { 517 assert((Kind == IK_Direct || Kind == IK_Value) && 518 "Only direct- and value-initialization have parentheses"); 519 return SourceRange(Locations[1], Locations[2]); 520 } 521}; 522 523/// \brief Describes the sequence of initializations required to initialize 524/// a given object or reference with a set of arguments. 525class InitializationSequence { 526public: 527 /// \brief Describes the kind of initialization sequence computed. 528 enum SequenceKind { 529 /// \brief A failed initialization sequence. The failure kind tells what 530 /// happened. 531 FailedSequence = 0, 532 533 /// \brief A dependent initialization, which could not be 534 /// type-checked due to the presence of dependent types or 535 /// dependently-typed expressions. 536 DependentSequence, 537 538 /// \brief A normal sequence. 539 NormalSequence 540 }; 541 542 /// \brief Describes the kind of a particular step in an initialization 543 /// sequence. 544 enum StepKind { 545 /// \brief Resolve the address of an overloaded function to a specific 546 /// function declaration. 547 SK_ResolveAddressOfOverloadedFunction, 548 /// \brief Perform a derived-to-base cast, producing an rvalue. 549 SK_CastDerivedToBaseRValue, 550 /// \brief Perform a derived-to-base cast, producing an xvalue. 551 SK_CastDerivedToBaseXValue, 552 /// \brief Perform a derived-to-base cast, producing an lvalue. 553 SK_CastDerivedToBaseLValue, 554 /// \brief Reference binding to an lvalue. 555 SK_BindReference, 556 /// \brief Reference binding to a temporary. 557 SK_BindReferenceToTemporary, 558 /// \brief An optional copy of a temporary object to another 559 /// temporary object, which is permitted (but not required) by 560 /// C++98/03 but not C++0x. 561 SK_ExtraneousCopyToTemporary, 562 /// \brief Perform a user-defined conversion, either via a conversion 563 /// function or via a constructor. 564 SK_UserConversion, 565 /// \brief Perform a qualification conversion, producing an rvalue. 566 SK_QualificationConversionRValue, 567 /// \brief Perform a qualification conversion, producing an xvalue. 568 SK_QualificationConversionXValue, 569 /// \brief Perform a qualification conversion, producing an lvalue. 570 SK_QualificationConversionLValue, 571 /// \brief Perform an implicit conversion sequence. 572 SK_ConversionSequence, 573 /// \brief Perform list-initialization without a constructor 574 SK_ListInitialization, 575 /// \brief Perform list-initialization with a constructor. 576 SK_ListConstructorCall, 577 /// \brief Unwrap the single-element initializer list for a reference. 578 SK_UnwrapInitList, 579 /// \brief Rewrap the single-element initializer list for a reference. 580 SK_RewrapInitList, 581 /// \brief Perform initialization via a constructor. 582 SK_ConstructorInitialization, 583 /// \brief Zero-initialize the object 584 SK_ZeroInitialization, 585 /// \brief C assignment 586 SK_CAssignment, 587 /// \brief Initialization by string 588 SK_StringInit, 589 /// \brief An initialization that "converts" an Objective-C object 590 /// (not a point to an object) to another Objective-C object type. 591 SK_ObjCObjectConversion, 592 /// \brief Array initialization (from an array rvalue). 593 /// This is a GNU C extension. 594 SK_ArrayInit, 595 /// \brief Array initialization from a parenthesized initializer list. 596 /// This is a GNU C++ extension. 597 SK_ParenthesizedArrayInit, 598 /// \brief Pass an object by indirect copy-and-restore. 599 SK_PassByIndirectCopyRestore, 600 /// \brief Pass an object by indirect restore. 601 SK_PassByIndirectRestore, 602 /// \brief Produce an Objective-C object pointer. 603 SK_ProduceObjCObject, 604 /// \brief Construct a std::initializer_list from an initializer list. 605 SK_StdInitializerList 606 }; 607 608 /// \brief A single step in the initialization sequence. 609 class Step { 610 public: 611 /// \brief The kind of conversion or initialization step we are taking. 612 StepKind Kind; 613 614 // \brief The type that results from this initialization. 615 QualType Type; 616 617 union { 618 /// \brief When Kind == SK_ResolvedOverloadedFunction or Kind == 619 /// SK_UserConversion, the function that the expression should be 620 /// resolved to or the conversion function to call, respectively. 621 /// When Kind == SK_ConstructorInitialization or SK_ListConstruction, 622 /// the constructor to be called. 623 /// 624 /// Always a FunctionDecl, plus a Boolean flag telling if it was 625 /// selected from an overloaded set having size greater than 1. 626 /// For conversion decls, the naming class is the source type. 627 /// For construct decls, the naming class is the target type. 628 struct { 629 bool HadMultipleCandidates; 630 FunctionDecl *Function; 631 DeclAccessPair FoundDecl; 632 } Function; 633 634 /// \brief When Kind = SK_ConversionSequence, the implicit conversion 635 /// sequence. 636 ImplicitConversionSequence *ICS; 637 638 /// \brief When Kind = SK_RewrapInitList, the syntactic form of the 639 /// wrapping list. 640 InitListExpr *WrappingSyntacticList; 641 }; 642 643 void Destroy(); 644 }; 645 646private: 647 /// \brief The kind of initialization sequence computed. 648 enum SequenceKind SequenceKind; 649 650 /// \brief Steps taken by this initialization. 651 SmallVector<Step, 4> Steps; 652 653public: 654 /// \brief Describes why initialization failed. 655 enum FailureKind { 656 /// \brief Too many initializers provided for a reference. 657 FK_TooManyInitsForReference, 658 /// \brief Array must be initialized with an initializer list. 659 FK_ArrayNeedsInitList, 660 /// \brief Array must be initialized with an initializer list or a 661 /// string literal. 662 FK_ArrayNeedsInitListOrStringLiteral, 663 /// \brief Array type mismatch. 664 FK_ArrayTypeMismatch, 665 /// \brief Non-constant array initializer 666 FK_NonConstantArrayInit, 667 /// \brief Cannot resolve the address of an overloaded function. 668 FK_AddressOfOverloadFailed, 669 /// \brief Overloading due to reference initialization failed. 670 FK_ReferenceInitOverloadFailed, 671 /// \brief Non-const lvalue reference binding to a temporary. 672 FK_NonConstLValueReferenceBindingToTemporary, 673 /// \brief Non-const lvalue reference binding to an lvalue of unrelated 674 /// type. 675 FK_NonConstLValueReferenceBindingToUnrelated, 676 /// \brief Rvalue reference binding to an lvalue. 677 FK_RValueReferenceBindingToLValue, 678 /// \brief Reference binding drops qualifiers. 679 FK_ReferenceInitDropsQualifiers, 680 /// \brief Reference binding failed. 681 FK_ReferenceInitFailed, 682 /// \brief Implicit conversion failed. 683 FK_ConversionFailed, 684 /// \brief Implicit conversion failed. 685 FK_ConversionFromPropertyFailed, 686 /// \brief Too many initializers for scalar 687 FK_TooManyInitsForScalar, 688 /// \brief Reference initialization from an initializer list 689 FK_ReferenceBindingToInitList, 690 /// \brief Initialization of some unused destination type with an 691 /// initializer list. 692 FK_InitListBadDestinationType, 693 /// \brief Overloading for a user-defined conversion failed. 694 FK_UserConversionOverloadFailed, 695 /// \brief Overloading for initialization by constructor failed. 696 FK_ConstructorOverloadFailed, 697 /// \brief Overloading for list-initialization by constructor failed. 698 FK_ListConstructorOverloadFailed, 699 /// \brief Default-initialization of a 'const' object. 700 FK_DefaultInitOfConst, 701 /// \brief Initialization of an incomplete type. 702 FK_Incomplete, 703 /// \brief Variable-length array must not have an initializer. 704 FK_VariableLengthArrayHasInitializer, 705 /// \brief List initialization failed at some point. 706 FK_ListInitializationFailed, 707 /// \brief Initializer has a placeholder type which cannot be 708 /// resolved by initialization. 709 FK_PlaceholderType, 710 /// \brief Failed to initialize a std::initializer_list because copy 711 /// construction of some element failed. 712 FK_InitListElementCopyFailure 713 }; 714 715private: 716 /// \brief The reason why initialization failed. 717 FailureKind Failure; 718 719 /// \brief The failed result of overload resolution. 720 OverloadingResult FailedOverloadResult; 721 722 /// \brief The candidate set created when initialization failed. 723 OverloadCandidateSet FailedCandidateSet; 724 725 /// \brief Prints a follow-up note that highlights the location of 726 /// the initialized entity, if it's remote. 727 void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity); 728 729public: 730 /// \brief Try to perform initialization of the given entity, creating a 731 /// record of the steps required to perform the initialization. 732 /// 733 /// The generated initialization sequence will either contain enough 734 /// information to diagnose 735 /// 736 /// \param S the semantic analysis object. 737 /// 738 /// \param Entity the entity being initialized. 739 /// 740 /// \param Kind the kind of initialization being performed. 741 /// 742 /// \param Args the argument(s) provided for initialization. 743 /// 744 /// \param NumArgs the number of arguments provided for initialization. 745 InitializationSequence(Sema &S, 746 const InitializedEntity &Entity, 747 const InitializationKind &Kind, 748 Expr **Args, 749 unsigned NumArgs); 750 751 ~InitializationSequence(); 752 753 /// \brief Perform the actual initialization of the given entity based on 754 /// the computed initialization sequence. 755 /// 756 /// \param S the semantic analysis object. 757 /// 758 /// \param Entity the entity being initialized. 759 /// 760 /// \param Kind the kind of initialization being performed. 761 /// 762 /// \param Args the argument(s) provided for initialization, ownership of 763 /// which is transferred into the routine. 764 /// 765 /// \param ResultType if non-NULL, will be set to the type of the 766 /// initialized object, which is the type of the declaration in most 767 /// cases. However, when the initialized object is a variable of 768 /// incomplete array type and the initializer is an initializer 769 /// list, this type will be set to the completed array type. 770 /// 771 /// \returns an expression that performs the actual object initialization, if 772 /// the initialization is well-formed. Otherwise, emits diagnostics 773 /// and returns an invalid expression. 774 ExprResult Perform(Sema &S, 775 const InitializedEntity &Entity, 776 const InitializationKind &Kind, 777 MultiExprArg Args, 778 QualType *ResultType = 0); 779 780 /// \brief Diagnose an potentially-invalid initialization sequence. 781 /// 782 /// \returns true if the initialization sequence was ill-formed, 783 /// false otherwise. 784 bool Diagnose(Sema &S, 785 const InitializedEntity &Entity, 786 const InitializationKind &Kind, 787 Expr **Args, unsigned NumArgs); 788 789 /// \brief Determine the kind of initialization sequence computed. 790 enum SequenceKind getKind() const { return SequenceKind; } 791 792 /// \brief Set the kind of sequence computed. 793 void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; } 794 795 /// \brief Determine whether the initialization sequence is valid. 796 operator bool() const { return !Failed(); } 797 798 /// \brief Determine whether the initialization sequence is invalid. 799 bool Failed() const { return SequenceKind == FailedSequence; } 800 801 typedef SmallVector<Step, 4>::const_iterator step_iterator; 802 step_iterator step_begin() const { return Steps.begin(); } 803 step_iterator step_end() const { return Steps.end(); } 804 805 /// \brief Determine whether this initialization is a direct reference 806 /// binding (C++ [dcl.init.ref]). 807 bool isDirectReferenceBinding() const; 808 809 /// \brief Determine whether this initialization failed due to an ambiguity. 810 bool isAmbiguous() const; 811 812 /// \brief Determine whether this initialization is direct call to a 813 /// constructor. 814 bool isConstructorInitialization() const; 815 816 /// \brief Returns whether the last step in this initialization sequence is a 817 /// narrowing conversion, defined by C++0x [dcl.init.list]p7. 818 /// 819 /// If this function returns true, *isInitializerConstant will be set to 820 /// describe whether *Initializer was a constant expression. If 821 /// *isInitializerConstant is set to true, *ConstantValue will be set to the 822 /// evaluated value of *Initializer. 823 bool endsWithNarrowing(ASTContext &Ctx, const Expr *Initializer, 824 bool *isInitializerConstant, 825 APValue *ConstantValue) const; 826 827 /// \brief Add a new step in the initialization that resolves the address 828 /// of an overloaded function to a specific function declaration. 829 /// 830 /// \param Function the function to which the overloaded function reference 831 /// resolves. 832 void AddAddressOverloadResolutionStep(FunctionDecl *Function, 833 DeclAccessPair Found, 834 bool HadMultipleCandidates); 835 836 /// \brief Add a new step in the initialization that performs a derived-to- 837 /// base cast. 838 /// 839 /// \param BaseType the base type to which we will be casting. 840 /// 841 /// \param IsLValue true if the result of this cast will be treated as 842 /// an lvalue. 843 void AddDerivedToBaseCastStep(QualType BaseType, 844 ExprValueKind Category); 845 846 /// \brief Add a new step binding a reference to an object. 847 /// 848 /// \param BindingTemporary True if we are binding a reference to a temporary 849 /// object (thereby extending its lifetime); false if we are binding to an 850 /// lvalue or an lvalue treated as an rvalue. 851 /// 852 /// \param UnnecessaryCopy True if we should check for a copy 853 /// constructor for a completely unnecessary but 854 void AddReferenceBindingStep(QualType T, bool BindingTemporary); 855 856 /// \brief Add a new step that makes an extraneous copy of the input 857 /// to a temporary of the same class type. 858 /// 859 /// This extraneous copy only occurs during reference binding in 860 /// C++98/03, where we are permitted (but not required) to introduce 861 /// an extra copy. At a bare minimum, we must check that we could 862 /// call the copy constructor, and produce a diagnostic if the copy 863 /// constructor is inaccessible or no copy constructor matches. 864 // 865 /// \param T The type of the temporary being created. 866 void AddExtraneousCopyToTemporary(QualType T); 867 868 /// \brief Add a new step invoking a conversion function, which is either 869 /// a constructor or a conversion function. 870 void AddUserConversionStep(FunctionDecl *Function, 871 DeclAccessPair FoundDecl, 872 QualType T, 873 bool HadMultipleCandidates); 874 875 /// \brief Add a new step that performs a qualification conversion to the 876 /// given type. 877 void AddQualificationConversionStep(QualType Ty, 878 ExprValueKind Category); 879 880 /// \brief Add a new step that applies an implicit conversion sequence. 881 void AddConversionSequenceStep(const ImplicitConversionSequence &ICS, 882 QualType T); 883 884 /// \brief Add a list-initialization step. 885 void AddListInitializationStep(QualType T); 886 887 /// \brief Add a constructor-initialization step. 888 /// 889 /// \arg FromInitList The constructor call is syntactically an initializer 890 /// list. 891 /// \arg AsInitList The constructor is called as an init list constructor. 892 void AddConstructorInitializationStep(CXXConstructorDecl *Constructor, 893 AccessSpecifier Access, 894 QualType T, 895 bool HadMultipleCandidates, 896 bool FromInitList, bool AsInitList); 897 898 /// \brief Add a zero-initialization step. 899 void AddZeroInitializationStep(QualType T); 900 901 /// \brief Add a C assignment step. 902 // 903 // FIXME: It isn't clear whether this should ever be needed; 904 // ideally, we would handle everything needed in C in the common 905 // path. However, that isn't the case yet. 906 void AddCAssignmentStep(QualType T); 907 908 /// \brief Add a string init step. 909 void AddStringInitStep(QualType T); 910 911 /// \brief Add an Objective-C object conversion step, which is 912 /// always a no-op. 913 void AddObjCObjectConversionStep(QualType T); 914 915 /// \brief Add an array initialization step. 916 void AddArrayInitStep(QualType T); 917 918 /// \brief Add a parenthesized array initialization step. 919 void AddParenthesizedArrayInitStep(QualType T); 920 921 /// \brief Add a step to pass an object by indirect copy-restore. 922 void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy); 923 924 /// \brief Add a step to "produce" an Objective-C object (by 925 /// retaining it). 926 void AddProduceObjCObjectStep(QualType T); 927 928 /// \brief Add a step to construct a std::initializer_list object from an 929 /// initializer list. 930 void AddStdInitializerListConstructionStep(QualType T); 931 932 /// \brief Add steps to unwrap a initializer list for a reference around a 933 /// single element and rewrap it at the end. 934 void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic); 935 936 /// \brief Note that this initialization sequence failed. 937 void SetFailed(FailureKind Failure) { 938 SequenceKind = FailedSequence; 939 this->Failure = Failure; 940 } 941 942 /// \brief Note that this initialization sequence failed due to failed 943 /// overload resolution. 944 void SetOverloadFailure(FailureKind Failure, OverloadingResult Result); 945 946 /// \brief Retrieve a reference to the candidate set when overload 947 /// resolution fails. 948 OverloadCandidateSet &getFailedCandidateSet() { 949 return FailedCandidateSet; 950 } 951 952 /// \brief Get the overloading result, for when the initialization 953 /// sequence failed due to a bad overload. 954 OverloadingResult getFailedOverloadResult() const { 955 return FailedOverloadResult; 956 } 957 958 /// \brief Determine why initialization failed. 959 FailureKind getFailureKind() const { 960 assert(Failed() && "Not an initialization failure!"); 961 return Failure; 962 } 963 964 /// \brief Dump a representation of this initialization sequence to 965 /// the given stream, for debugging purposes. 966 void dump(raw_ostream &OS) const; 967 968 /// \brief Dump a representation of this initialization sequence to 969 /// standard error, for debugging purposes. 970 void dump() const; 971}; 972 973} // end namespace clang 974 975#endif // LLVM_CLANG_SEMA_INITIALIZATION_H 976