Initialization.h revision 70e24fccc8ef4aa8be03a778e9655bfcfa79dd14
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.getLangOpts().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_ExplicitConvs, ///< Normal context, but allows explicit conversion funcs 380 IC_Implicit, ///< Implicit context (value initialization) 381 IC_StaticCast, ///< Static cast context 382 IC_CStyleCast, ///< C-style cast context 383 IC_FunctionalCast ///< Functional cast context 384 }; 385 386 /// \brief The kind of initialization being performed. 387 InitKind Kind : 8; 388 389 /// \brief The context of the initialization. 390 InitContext Context : 8; 391 392 /// \brief The source locations involved in the initialization. 393 SourceLocation Locations[3]; 394 395 InitializationKind(InitKind Kind, InitContext Context, SourceLocation Loc1, 396 SourceLocation Loc2, SourceLocation Loc3) 397 : Kind(Kind), Context(Context) 398 { 399 Locations[0] = Loc1; 400 Locations[1] = Loc2; 401 Locations[2] = Loc3; 402 } 403 404public: 405 /// \brief Create a direct initialization. 406 static InitializationKind CreateDirect(SourceLocation InitLoc, 407 SourceLocation LParenLoc, 408 SourceLocation RParenLoc) { 409 return InitializationKind(IK_Direct, IC_Normal, 410 InitLoc, LParenLoc, RParenLoc); 411 } 412 413 static InitializationKind CreateDirectList(SourceLocation InitLoc) { 414 return InitializationKind(IK_DirectList, IC_Normal, 415 InitLoc, InitLoc, InitLoc); 416 } 417 418 /// \brief Create a direct initialization due to a cast that isn't a C-style 419 /// or functional cast. 420 static InitializationKind CreateCast(SourceRange TypeRange) { 421 return InitializationKind(IK_Direct, IC_StaticCast, TypeRange.getBegin(), 422 TypeRange.getBegin(), TypeRange.getEnd()); 423 } 424 425 /// \brief Create a direct initialization for a C-style cast. 426 static InitializationKind CreateCStyleCast(SourceLocation StartLoc, 427 SourceRange TypeRange, 428 bool InitList) { 429 // C++ cast syntax doesn't permit init lists, but C compound literals are 430 // exactly that. 431 return InitializationKind(InitList ? IK_DirectList : IK_Direct, 432 IC_CStyleCast, StartLoc, TypeRange.getBegin(), 433 TypeRange.getEnd()); 434 } 435 436 /// \brief Create a direct initialization for a functional cast. 437 static InitializationKind CreateFunctionalCast(SourceRange TypeRange, 438 bool InitList) { 439 return InitializationKind(InitList ? IK_DirectList : IK_Direct, 440 IC_FunctionalCast, TypeRange.getBegin(), 441 TypeRange.getBegin(), TypeRange.getEnd()); 442 } 443 444 /// \brief Create a copy initialization. 445 static InitializationKind CreateCopy(SourceLocation InitLoc, 446 SourceLocation EqualLoc, 447 bool AllowExplicitConvs = false) { 448 return InitializationKind(IK_Copy, 449 AllowExplicitConvs? IC_ExplicitConvs : IC_Normal, 450 InitLoc, EqualLoc, EqualLoc); 451 } 452 453 /// \brief Create a default initialization. 454 static InitializationKind CreateDefault(SourceLocation InitLoc) { 455 return InitializationKind(IK_Default, IC_Normal, InitLoc, InitLoc, InitLoc); 456 } 457 458 /// \brief Create a value initialization. 459 static InitializationKind CreateValue(SourceLocation InitLoc, 460 SourceLocation LParenLoc, 461 SourceLocation RParenLoc, 462 bool isImplicit = false) { 463 return InitializationKind(IK_Value, isImplicit ? IC_Implicit : IC_Normal, 464 InitLoc, LParenLoc, RParenLoc); 465 } 466 467 /// \brief Determine the initialization kind. 468 InitKind getKind() const { 469 return Kind; 470 } 471 472 /// \brief Determine whether this initialization is an explicit cast. 473 bool isExplicitCast() const { 474 return Context >= IC_StaticCast; 475 } 476 477 /// \brief Determine whether this initialization is a C-style cast. 478 bool isCStyleOrFunctionalCast() const { 479 return Context >= IC_CStyleCast; 480 } 481 482 /// \brief Determine whether this is a C-style cast. 483 bool isCStyleCast() const { 484 return Context == IC_CStyleCast; 485 } 486 487 /// \brief Determine whether this is a functional-style cast. 488 bool isFunctionalCast() const { 489 return Context == IC_FunctionalCast; 490 } 491 492 /// \brief Determine whether this initialization is an implicit 493 /// value-initialization, e.g., as occurs during aggregate 494 /// initialization. 495 bool isImplicitValueInit() const { return Context == IC_Implicit; } 496 497 /// \brief Retrieve the location at which initialization is occurring. 498 SourceLocation getLocation() const { return Locations[0]; } 499 500 /// \brief Retrieve the source range that covers the initialization. 501 SourceRange getRange() const { 502 return SourceRange(Locations[0], Locations[2]); 503 } 504 505 /// \brief Retrieve the location of the equal sign for copy initialization 506 /// (if present). 507 SourceLocation getEqualLoc() const { 508 assert(Kind == IK_Copy && "Only copy initialization has an '='"); 509 return Locations[1]; 510 } 511 512 bool isCopyInit() const { return Kind == IK_Copy; } 513 514 /// \brief Retrieve whether this initialization allows the use of explicit 515 /// constructors. 516 bool AllowExplicit() const { return !isCopyInit(); } 517 518 /// \brief Retrieve whether this initialization allows the use of explicit 519 /// conversion functions. 520 bool allowExplicitConversionFunctions() const { 521 return !isCopyInit() || Context == IC_ExplicitConvs; 522 } 523 524 /// \brief Retrieve the source range containing the locations of the open 525 /// and closing parentheses for value and direct initializations. 526 SourceRange getParenRange() const { 527 assert((Kind == IK_Direct || Kind == IK_Value) && 528 "Only direct- and value-initialization have parentheses"); 529 return SourceRange(Locations[1], Locations[2]); 530 } 531}; 532 533/// \brief Describes the sequence of initializations required to initialize 534/// a given object or reference with a set of arguments. 535class InitializationSequence { 536public: 537 /// \brief Describes the kind of initialization sequence computed. 538 enum SequenceKind { 539 /// \brief A failed initialization sequence. The failure kind tells what 540 /// happened. 541 FailedSequence = 0, 542 543 /// \brief A dependent initialization, which could not be 544 /// type-checked due to the presence of dependent types or 545 /// dependently-typed expressions. 546 DependentSequence, 547 548 /// \brief A normal sequence. 549 NormalSequence 550 }; 551 552 /// \brief Describes the kind of a particular step in an initialization 553 /// sequence. 554 enum StepKind { 555 /// \brief Resolve the address of an overloaded function to a specific 556 /// function declaration. 557 SK_ResolveAddressOfOverloadedFunction, 558 /// \brief Perform a derived-to-base cast, producing an rvalue. 559 SK_CastDerivedToBaseRValue, 560 /// \brief Perform a derived-to-base cast, producing an xvalue. 561 SK_CastDerivedToBaseXValue, 562 /// \brief Perform a derived-to-base cast, producing an lvalue. 563 SK_CastDerivedToBaseLValue, 564 /// \brief Reference binding to an lvalue. 565 SK_BindReference, 566 /// \brief Reference binding to a temporary. 567 SK_BindReferenceToTemporary, 568 /// \brief An optional copy of a temporary object to another 569 /// temporary object, which is permitted (but not required) by 570 /// C++98/03 but not C++0x. 571 SK_ExtraneousCopyToTemporary, 572 /// \brief Perform a user-defined conversion, either via a conversion 573 /// function or via a constructor. 574 SK_UserConversion, 575 /// \brief Perform a qualification conversion, producing an rvalue. 576 SK_QualificationConversionRValue, 577 /// \brief Perform a qualification conversion, producing an xvalue. 578 SK_QualificationConversionXValue, 579 /// \brief Perform a qualification conversion, producing an lvalue. 580 SK_QualificationConversionLValue, 581 /// \brief Perform an implicit conversion sequence. 582 SK_ConversionSequence, 583 /// \brief Perform list-initialization without a constructor 584 SK_ListInitialization, 585 /// \brief Perform list-initialization with a constructor. 586 SK_ListConstructorCall, 587 /// \brief Unwrap the single-element initializer list for a reference. 588 SK_UnwrapInitList, 589 /// \brief Rewrap the single-element initializer list for a reference. 590 SK_RewrapInitList, 591 /// \brief Perform initialization via a constructor. 592 SK_ConstructorInitialization, 593 /// \brief Zero-initialize the object 594 SK_ZeroInitialization, 595 /// \brief C assignment 596 SK_CAssignment, 597 /// \brief Initialization by string 598 SK_StringInit, 599 /// \brief An initialization that "converts" an Objective-C object 600 /// (not a point to an object) to another Objective-C object type. 601 SK_ObjCObjectConversion, 602 /// \brief Array initialization (from an array rvalue). 603 /// This is a GNU C extension. 604 SK_ArrayInit, 605 /// \brief Array initialization from a parenthesized initializer list. 606 /// This is a GNU C++ extension. 607 SK_ParenthesizedArrayInit, 608 /// \brief Pass an object by indirect copy-and-restore. 609 SK_PassByIndirectCopyRestore, 610 /// \brief Pass an object by indirect restore. 611 SK_PassByIndirectRestore, 612 /// \brief Produce an Objective-C object pointer. 613 SK_ProduceObjCObject, 614 /// \brief Construct a std::initializer_list from an initializer list. 615 SK_StdInitializerList 616 }; 617 618 /// \brief A single step in the initialization sequence. 619 class Step { 620 public: 621 /// \brief The kind of conversion or initialization step we are taking. 622 StepKind Kind; 623 624 // \brief The type that results from this initialization. 625 QualType Type; 626 627 union { 628 /// \brief When Kind == SK_ResolvedOverloadedFunction or Kind == 629 /// SK_UserConversion, the function that the expression should be 630 /// resolved to or the conversion function to call, respectively. 631 /// When Kind == SK_ConstructorInitialization or SK_ListConstruction, 632 /// the constructor to be called. 633 /// 634 /// Always a FunctionDecl, plus a Boolean flag telling if it was 635 /// selected from an overloaded set having size greater than 1. 636 /// For conversion decls, the naming class is the source type. 637 /// For construct decls, the naming class is the target type. 638 struct { 639 bool HadMultipleCandidates; 640 FunctionDecl *Function; 641 DeclAccessPair FoundDecl; 642 } Function; 643 644 /// \brief When Kind = SK_ConversionSequence, the implicit conversion 645 /// sequence. 646 ImplicitConversionSequence *ICS; 647 648 /// \brief When Kind = SK_RewrapInitList, the syntactic form of the 649 /// wrapping list. 650 InitListExpr *WrappingSyntacticList; 651 }; 652 653 void Destroy(); 654 }; 655 656private: 657 /// \brief The kind of initialization sequence computed. 658 enum SequenceKind SequenceKind; 659 660 /// \brief Steps taken by this initialization. 661 SmallVector<Step, 4> Steps; 662 663public: 664 /// \brief Describes why initialization failed. 665 enum FailureKind { 666 /// \brief Too many initializers provided for a reference. 667 FK_TooManyInitsForReference, 668 /// \brief Array must be initialized with an initializer list. 669 FK_ArrayNeedsInitList, 670 /// \brief Array must be initialized with an initializer list or a 671 /// string literal. 672 FK_ArrayNeedsInitListOrStringLiteral, 673 /// \brief Array type mismatch. 674 FK_ArrayTypeMismatch, 675 /// \brief Non-constant array initializer 676 FK_NonConstantArrayInit, 677 /// \brief Cannot resolve the address of an overloaded function. 678 FK_AddressOfOverloadFailed, 679 /// \brief Overloading due to reference initialization failed. 680 FK_ReferenceInitOverloadFailed, 681 /// \brief Non-const lvalue reference binding to a temporary. 682 FK_NonConstLValueReferenceBindingToTemporary, 683 /// \brief Non-const lvalue reference binding to an lvalue of unrelated 684 /// type. 685 FK_NonConstLValueReferenceBindingToUnrelated, 686 /// \brief Rvalue reference binding to an lvalue. 687 FK_RValueReferenceBindingToLValue, 688 /// \brief Reference binding drops qualifiers. 689 FK_ReferenceInitDropsQualifiers, 690 /// \brief Reference binding failed. 691 FK_ReferenceInitFailed, 692 /// \brief Implicit conversion failed. 693 FK_ConversionFailed, 694 /// \brief Implicit conversion failed. 695 FK_ConversionFromPropertyFailed, 696 /// \brief Too many initializers for scalar 697 FK_TooManyInitsForScalar, 698 /// \brief Reference initialization from an initializer list 699 FK_ReferenceBindingToInitList, 700 /// \brief Initialization of some unused destination type with an 701 /// initializer list. 702 FK_InitListBadDestinationType, 703 /// \brief Overloading for a user-defined conversion failed. 704 FK_UserConversionOverloadFailed, 705 /// \brief Overloading for initialization by constructor failed. 706 FK_ConstructorOverloadFailed, 707 /// \brief Overloading for list-initialization by constructor failed. 708 FK_ListConstructorOverloadFailed, 709 /// \brief Default-initialization of a 'const' object. 710 FK_DefaultInitOfConst, 711 /// \brief Initialization of an incomplete type. 712 FK_Incomplete, 713 /// \brief Variable-length array must not have an initializer. 714 FK_VariableLengthArrayHasInitializer, 715 /// \brief List initialization failed at some point. 716 FK_ListInitializationFailed, 717 /// \brief Initializer has a placeholder type which cannot be 718 /// resolved by initialization. 719 FK_PlaceholderType, 720 /// \brief Failed to initialize a std::initializer_list because copy 721 /// construction of some element failed. 722 FK_InitListElementCopyFailure, 723 /// \brief List-copy-initialization chose an explicit constructor. 724 FK_ExplicitConstructor 725 }; 726 727private: 728 /// \brief The reason why initialization failed. 729 FailureKind Failure; 730 731 /// \brief The failed result of overload resolution. 732 OverloadingResult FailedOverloadResult; 733 734 /// \brief The candidate set created when initialization failed. 735 OverloadCandidateSet FailedCandidateSet; 736 737 /// \brief Prints a follow-up note that highlights the location of 738 /// the initialized entity, if it's remote. 739 void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity); 740 741public: 742 /// \brief Try to perform initialization of the given entity, creating a 743 /// record of the steps required to perform the initialization. 744 /// 745 /// The generated initialization sequence will either contain enough 746 /// information to diagnose 747 /// 748 /// \param S the semantic analysis object. 749 /// 750 /// \param Entity the entity being initialized. 751 /// 752 /// \param Kind the kind of initialization being performed. 753 /// 754 /// \param Args the argument(s) provided for initialization. 755 /// 756 /// \param NumArgs the number of arguments provided for initialization. 757 InitializationSequence(Sema &S, 758 const InitializedEntity &Entity, 759 const InitializationKind &Kind, 760 Expr **Args, 761 unsigned NumArgs); 762 763 ~InitializationSequence(); 764 765 /// \brief Perform the actual initialization of the given entity based on 766 /// the computed initialization sequence. 767 /// 768 /// \param S the semantic analysis object. 769 /// 770 /// \param Entity the entity being initialized. 771 /// 772 /// \param Kind the kind of initialization being performed. 773 /// 774 /// \param Args the argument(s) provided for initialization, ownership of 775 /// which is transferred into the routine. 776 /// 777 /// \param ResultType if non-NULL, will be set to the type of the 778 /// initialized object, which is the type of the declaration in most 779 /// cases. However, when the initialized object is a variable of 780 /// incomplete array type and the initializer is an initializer 781 /// list, this type will be set to the completed array type. 782 /// 783 /// \returns an expression that performs the actual object initialization, if 784 /// the initialization is well-formed. Otherwise, emits diagnostics 785 /// and returns an invalid expression. 786 ExprResult Perform(Sema &S, 787 const InitializedEntity &Entity, 788 const InitializationKind &Kind, 789 MultiExprArg Args, 790 QualType *ResultType = 0); 791 792 /// \brief Diagnose an potentially-invalid initialization sequence. 793 /// 794 /// \returns true if the initialization sequence was ill-formed, 795 /// false otherwise. 796 bool Diagnose(Sema &S, 797 const InitializedEntity &Entity, 798 const InitializationKind &Kind, 799 Expr **Args, unsigned NumArgs); 800 801 /// \brief Determine the kind of initialization sequence computed. 802 enum SequenceKind getKind() const { return SequenceKind; } 803 804 /// \brief Set the kind of sequence computed. 805 void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; } 806 807 /// \brief Determine whether the initialization sequence is valid. 808 operator bool() const { return !Failed(); } 809 810 /// \brief Determine whether the initialization sequence is invalid. 811 bool Failed() const { return SequenceKind == FailedSequence; } 812 813 typedef SmallVector<Step, 4>::const_iterator step_iterator; 814 step_iterator step_begin() const { return Steps.begin(); } 815 step_iterator step_end() const { return Steps.end(); } 816 817 /// \brief Determine whether this initialization is a direct reference 818 /// binding (C++ [dcl.init.ref]). 819 bool isDirectReferenceBinding() const; 820 821 /// \brief Determine whether this initialization failed due to an ambiguity. 822 bool isAmbiguous() const; 823 824 /// \brief Determine whether this initialization is direct call to a 825 /// constructor. 826 bool isConstructorInitialization() const; 827 828 /// \brief Returns whether the last step in this initialization sequence is a 829 /// narrowing conversion, defined by C++0x [dcl.init.list]p7. 830 /// 831 /// If this function returns true, *isInitializerConstant will be set to 832 /// describe whether *Initializer was a constant expression. If 833 /// *isInitializerConstant is set to true, *ConstantValue will be set to the 834 /// evaluated value of *Initializer. 835 bool endsWithNarrowing(ASTContext &Ctx, const Expr *Initializer, 836 bool *isInitializerConstant, 837 APValue *ConstantValue) const; 838 839 /// \brief Add a new step in the initialization that resolves the address 840 /// of an overloaded function to a specific function declaration. 841 /// 842 /// \param Function the function to which the overloaded function reference 843 /// resolves. 844 void AddAddressOverloadResolutionStep(FunctionDecl *Function, 845 DeclAccessPair Found, 846 bool HadMultipleCandidates); 847 848 /// \brief Add a new step in the initialization that performs a derived-to- 849 /// base cast. 850 /// 851 /// \param BaseType the base type to which we will be casting. 852 /// 853 /// \param IsLValue true if the result of this cast will be treated as 854 /// an lvalue. 855 void AddDerivedToBaseCastStep(QualType BaseType, 856 ExprValueKind Category); 857 858 /// \brief Add a new step binding a reference to an object. 859 /// 860 /// \param BindingTemporary True if we are binding a reference to a temporary 861 /// object (thereby extending its lifetime); false if we are binding to an 862 /// lvalue or an lvalue treated as an rvalue. 863 /// 864 /// \param UnnecessaryCopy True if we should check for a copy 865 /// constructor for a completely unnecessary but 866 void AddReferenceBindingStep(QualType T, bool BindingTemporary); 867 868 /// \brief Add a new step that makes an extraneous copy of the input 869 /// to a temporary of the same class type. 870 /// 871 /// This extraneous copy only occurs during reference binding in 872 /// C++98/03, where we are permitted (but not required) to introduce 873 /// an extra copy. At a bare minimum, we must check that we could 874 /// call the copy constructor, and produce a diagnostic if the copy 875 /// constructor is inaccessible or no copy constructor matches. 876 // 877 /// \param T The type of the temporary being created. 878 void AddExtraneousCopyToTemporary(QualType T); 879 880 /// \brief Add a new step invoking a conversion function, which is either 881 /// a constructor or a conversion function. 882 void AddUserConversionStep(FunctionDecl *Function, 883 DeclAccessPair FoundDecl, 884 QualType T, 885 bool HadMultipleCandidates); 886 887 /// \brief Add a new step that performs a qualification conversion to the 888 /// given type. 889 void AddQualificationConversionStep(QualType Ty, 890 ExprValueKind Category); 891 892 /// \brief Add a new step that applies an implicit conversion sequence. 893 void AddConversionSequenceStep(const ImplicitConversionSequence &ICS, 894 QualType T); 895 896 /// \brief Add a list-initialization step. 897 void AddListInitializationStep(QualType T); 898 899 /// \brief Add a constructor-initialization step. 900 /// 901 /// \arg FromInitList The constructor call is syntactically an initializer 902 /// list. 903 /// \arg AsInitList The constructor is called as an init list constructor. 904 void AddConstructorInitializationStep(CXXConstructorDecl *Constructor, 905 AccessSpecifier Access, 906 QualType T, 907 bool HadMultipleCandidates, 908 bool FromInitList, bool AsInitList); 909 910 /// \brief Add a zero-initialization step. 911 void AddZeroInitializationStep(QualType T); 912 913 /// \brief Add a C assignment step. 914 // 915 // FIXME: It isn't clear whether this should ever be needed; 916 // ideally, we would handle everything needed in C in the common 917 // path. However, that isn't the case yet. 918 void AddCAssignmentStep(QualType T); 919 920 /// \brief Add a string init step. 921 void AddStringInitStep(QualType T); 922 923 /// \brief Add an Objective-C object conversion step, which is 924 /// always a no-op. 925 void AddObjCObjectConversionStep(QualType T); 926 927 /// \brief Add an array initialization step. 928 void AddArrayInitStep(QualType T); 929 930 /// \brief Add a parenthesized array initialization step. 931 void AddParenthesizedArrayInitStep(QualType T); 932 933 /// \brief Add a step to pass an object by indirect copy-restore. 934 void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy); 935 936 /// \brief Add a step to "produce" an Objective-C object (by 937 /// retaining it). 938 void AddProduceObjCObjectStep(QualType T); 939 940 /// \brief Add a step to construct a std::initializer_list object from an 941 /// initializer list. 942 void AddStdInitializerListConstructionStep(QualType T); 943 944 /// \brief Add steps to unwrap a initializer list for a reference around a 945 /// single element and rewrap it at the end. 946 void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic); 947 948 /// \brief Note that this initialization sequence failed. 949 void SetFailed(FailureKind Failure) { 950 SequenceKind = FailedSequence; 951 this->Failure = Failure; 952 } 953 954 /// \brief Note that this initialization sequence failed due to failed 955 /// overload resolution. 956 void SetOverloadFailure(FailureKind Failure, OverloadingResult Result); 957 958 /// \brief Retrieve a reference to the candidate set when overload 959 /// resolution fails. 960 OverloadCandidateSet &getFailedCandidateSet() { 961 return FailedCandidateSet; 962 } 963 964 /// \brief Get the overloading result, for when the initialization 965 /// sequence failed due to a bad overload. 966 OverloadingResult getFailedOverloadResult() const { 967 return FailedOverloadResult; 968 } 969 970 /// \brief Determine why initialization failed. 971 FailureKind getFailureKind() const { 972 assert(Failed() && "Not an initialization failure!"); 973 return Failure; 974 } 975 976 /// \brief Dump a representation of this initialization sequence to 977 /// the given stream, for debugging purposes. 978 void dump(raw_ostream &OS) const; 979 980 /// \brief Dump a representation of this initialization sequence to 981 /// standard error, for debugging purposes. 982 void dump() const; 983}; 984 985} // end namespace clang 986 987#endif // LLVM_CLANG_SEMA_INITIALIZATION_H 988