1 //===- Initialization.h - Semantic Analysis for Initializers ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file provides supporting data types for initialization of objects.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_SEMA_INITIALIZATION_H
15 #define LLVM_CLANG_SEMA_INITIALIZATION_H
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/Attr.h"
19 #include "clang/AST/Decl.h"
20 #include "clang/AST/DeclAccessPair.h"
21 #include "clang/AST/DeclarationName.h"
22 #include "clang/AST/Expr.h"
23 #include "clang/AST/Type.h"
24 #include "clang/Basic/IdentifierTable.h"
25 #include "clang/Basic/LLVM.h"
26 #include "clang/Basic/LangOptions.h"
27 #include "clang/Basic/SourceLocation.h"
28 #include "clang/Basic/Specifiers.h"
29 #include "clang/Sema/Overload.h"
30 #include "clang/Sema/Ownership.h"
31 #include "llvm/ADT/ArrayRef.h"
32 #include "llvm/ADT/SmallVector.h"
33 #include "llvm/ADT/StringRef.h"
34 #include "llvm/ADT/iterator_range.h"
35 #include "llvm/Support/Casting.h"
43 class CXXBaseSpecifier;
44 class CXXConstructorDecl;
48 /// Describes an entity that is being initialized.
49 class alignas(8) InitializedEntity {
51 /// Specifies the kind of entity being initialized.
53 /// The entity being initialized is a variable.
56 /// The entity being initialized is a function parameter.
59 /// The entity being initialized is the result of a function call.
62 /// The entity being initialized is the result of a statement expression.
65 /// The entity being initialized is an exception object that
69 /// The entity being initialized is a non-static data member
73 /// The entity being initialized is an element of an array.
76 /// The entity being initialized is an object (or array of
77 /// objects) allocated via new.
80 /// The entity being initialized is a temporary object.
83 /// The entity being initialized is a base member subobject.
86 /// The initialization is being done by a delegating constructor.
89 /// The entity being initialized is an element of a vector.
93 /// The entity being initialized is a field of block descriptor for
94 /// the copied-in c++ object.
97 /// The entity being initialized is a field of block descriptor for the
98 /// copied-in lambda object that's used in the lambda to block conversion.
99 EK_LambdaToBlockConversionBlockElement,
101 /// The entity being initialized is the real or imaginary part of a
105 /// The entity being initialized is the field that captures a
106 /// variable in a lambda.
109 /// The entity being initialized is the initializer for a compound
111 EK_CompoundLiteralInit,
113 /// The entity being implicitly initialized back to the formal
117 /// The entity being initialized is a function parameter; function
118 /// is member of group of audited CF APIs.
119 EK_Parameter_CF_Audited,
121 /// The entity being initialized is a structured binding of a
122 /// decomposition declaration.
125 // Note: err_init_conversion_failed in DiagnosticSemaKinds.td uses this
126 // enum as an index for its first %select. When modifying this list,
127 // that diagnostic text needs to be updated as well.
131 /// The kind of entity being initialized.
134 /// If non-NULL, the parent entity in which this
135 /// initialization occurs.
136 const InitializedEntity *Parent = nullptr;
138 /// The type of the object or reference being initialized.
141 /// The mangling number for the next reference temporary to be created.
142 mutable unsigned ManglingNumber = 0;
145 /// When Kind == EK_Result, EK_Exception, EK_New, the
146 /// location of the 'return', 'throw', or 'new' keyword,
147 /// respectively. When Kind == EK_Temporary, the location where
148 /// the temporary is being created.
151 /// Whether the entity being initialized may end up using the
152 /// named return value optimization (NRVO).
157 /// The VarDecl, FieldDecl, or BindingDecl being initialized.
158 ValueDecl *VariableOrMember;
160 /// When Kind == EK_Member, whether this is an implicit member
161 /// initialization in a copy or move constructor. These can perform array
163 bool IsImplicitFieldInit;
165 /// When Kind == EK_Member, whether this is the initial initialization
166 /// check for a default member initializer.
167 bool IsDefaultMemberInit;
171 /// The name of the variable being captured by an EK_LambdaCapture.
172 IdentifierInfo *VarID;
174 /// The source location at which the capture occurs.
179 /// When Kind == EK_Variable, EK_Member or EK_Binding, the variable.
182 /// When Kind == EK_RelatedResult, the ObjectiveC method where
183 /// result type was implicitly changed to accommodate ARC semantics.
184 ObjCMethodDecl *MethodDecl;
186 /// When Kind == EK_Parameter, the ParmVarDecl, with the
187 /// low bit indicating whether the parameter is "consumed".
190 /// When Kind == EK_Temporary or EK_CompoundLiteralInit, the type
191 /// source information for the temporary.
192 TypeSourceInfo *TypeInfo;
194 struct LN LocAndNRVO;
196 /// When Kind == EK_Base, the base specifier that provides the
197 /// base class. The lower bit specifies whether the base is an inherited
201 /// When Kind == EK_ArrayElement, EK_VectorElement, or
202 /// EK_ComplexElement, the index of the array or vector element being
209 InitializedEntity() = default;
211 /// Create the initialization entity for a variable.
212 InitializedEntity(VarDecl *Var, EntityKind EK = EK_Variable)
213 : Kind(EK), Type(Var->getType()), Variable{Var, false, false} {}
215 /// Create the initialization entity for the result of a
216 /// function, throwing an object, performing an explicit cast, or
217 /// initializing a parameter for which there is no declaration.
218 InitializedEntity(EntityKind Kind, SourceLocation Loc, QualType Type,
220 : Kind(Kind), Type(Type) {
221 LocAndNRVO.Location = Loc.getRawEncoding();
222 LocAndNRVO.NRVO = NRVO;
225 /// Create the initialization entity for a member subobject.
226 InitializedEntity(FieldDecl *Member, const InitializedEntity *Parent,
227 bool Implicit, bool DefaultMemberInit)
228 : Kind(EK_Member), Parent(Parent), Type(Member->getType()),
229 Variable{Member, Implicit, DefaultMemberInit} {}
231 /// Create the initialization entity for an array element.
232 InitializedEntity(ASTContext &Context, unsigned Index,
233 const InitializedEntity &Parent);
235 /// Create the initialization entity for a lambda capture.
236 InitializedEntity(IdentifierInfo *VarID, QualType FieldType, SourceLocation Loc)
237 : Kind(EK_LambdaCapture), Type(FieldType) {
238 Capture.VarID = VarID;
239 Capture.Location = Loc.getRawEncoding();
243 /// Create the initialization entity for a variable.
244 static InitializedEntity InitializeVariable(VarDecl *Var) {
245 return InitializedEntity(Var);
248 /// Create the initialization entity for a parameter.
249 static InitializedEntity InitializeParameter(ASTContext &Context,
250 const ParmVarDecl *Parm) {
251 return InitializeParameter(Context, Parm, Parm->getType());
254 /// Create the initialization entity for a parameter, but use
256 static InitializedEntity InitializeParameter(ASTContext &Context,
257 const ParmVarDecl *Parm,
259 bool Consumed = (Context.getLangOpts().ObjCAutoRefCount &&
260 Parm->hasAttr<NSConsumedAttr>());
262 InitializedEntity Entity;
263 Entity.Kind = EK_Parameter;
265 Context.getVariableArrayDecayedType(Type.getUnqualifiedType());
266 Entity.Parent = nullptr;
268 = (static_cast<uintptr_t>(Consumed) | reinterpret_cast<uintptr_t>(Parm));
272 /// Create the initialization entity for a parameter that is
273 /// only known by its type.
274 static InitializedEntity InitializeParameter(ASTContext &Context,
277 InitializedEntity Entity;
278 Entity.Kind = EK_Parameter;
279 Entity.Type = Context.getVariableArrayDecayedType(Type);
280 Entity.Parent = nullptr;
281 Entity.Parameter = (Consumed);
285 /// Create the initialization entity for the result of a function.
286 static InitializedEntity InitializeResult(SourceLocation ReturnLoc,
287 QualType Type, bool NRVO) {
288 return InitializedEntity(EK_Result, ReturnLoc, Type, NRVO);
291 static InitializedEntity InitializeStmtExprResult(SourceLocation ReturnLoc,
293 return InitializedEntity(EK_StmtExprResult, ReturnLoc, Type);
296 static InitializedEntity InitializeBlock(SourceLocation BlockVarLoc,
297 QualType Type, bool NRVO) {
298 return InitializedEntity(EK_BlockElement, BlockVarLoc, Type, NRVO);
301 static InitializedEntity InitializeLambdaToBlock(SourceLocation BlockVarLoc,
302 QualType Type, bool NRVO) {
303 return InitializedEntity(EK_LambdaToBlockConversionBlockElement,
304 BlockVarLoc, Type, NRVO);
307 /// Create the initialization entity for an exception object.
308 static InitializedEntity InitializeException(SourceLocation ThrowLoc,
309 QualType Type, bool NRVO) {
310 return InitializedEntity(EK_Exception, ThrowLoc, Type, NRVO);
313 /// Create the initialization entity for an object allocated via new.
314 static InitializedEntity InitializeNew(SourceLocation NewLoc, QualType Type) {
315 return InitializedEntity(EK_New, NewLoc, Type);
318 /// Create the initialization entity for a temporary.
319 static InitializedEntity InitializeTemporary(QualType Type) {
320 return InitializeTemporary(nullptr, Type);
323 /// Create the initialization entity for a temporary.
324 static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo) {
325 return InitializeTemporary(TypeInfo, TypeInfo->getType());
328 /// Create the initialization entity for a temporary.
329 static InitializedEntity InitializeTemporary(TypeSourceInfo *TypeInfo,
331 InitializedEntity Result(EK_Temporary, SourceLocation(), Type);
332 Result.TypeInfo = TypeInfo;
336 /// Create the initialization entity for a related result.
337 static InitializedEntity InitializeRelatedResult(ObjCMethodDecl *MD,
339 InitializedEntity Result(EK_RelatedResult, SourceLocation(), Type);
340 Result.MethodDecl = MD;
344 /// Create the initialization entity for a base class subobject.
345 static InitializedEntity
346 InitializeBase(ASTContext &Context, const CXXBaseSpecifier *Base,
347 bool IsInheritedVirtualBase,
348 const InitializedEntity *Parent = nullptr);
350 /// Create the initialization entity for a delegated constructor.
351 static InitializedEntity InitializeDelegation(QualType Type) {
352 return InitializedEntity(EK_Delegating, SourceLocation(), Type);
355 /// Create the initialization entity for a member subobject.
356 static InitializedEntity
357 InitializeMember(FieldDecl *Member,
358 const InitializedEntity *Parent = nullptr,
359 bool Implicit = false) {
360 return InitializedEntity(Member, Parent, Implicit, false);
363 /// Create the initialization entity for a member subobject.
364 static InitializedEntity
365 InitializeMember(IndirectFieldDecl *Member,
366 const InitializedEntity *Parent = nullptr,
367 bool Implicit = false) {
368 return InitializedEntity(Member->getAnonField(), Parent, Implicit, false);
371 /// Create the initialization entity for a default member initializer.
372 static InitializedEntity
373 InitializeMemberFromDefaultMemberInitializer(FieldDecl *Member) {
374 return InitializedEntity(Member, nullptr, false, true);
377 /// Create the initialization entity for an array element.
378 static InitializedEntity InitializeElement(ASTContext &Context,
380 const InitializedEntity &Parent) {
381 return InitializedEntity(Context, Index, Parent);
384 /// Create the initialization entity for a structured binding.
385 static InitializedEntity InitializeBinding(VarDecl *Binding) {
386 return InitializedEntity(Binding, EK_Binding);
389 /// Create the initialization entity for a lambda capture.
390 static InitializedEntity InitializeLambdaCapture(IdentifierInfo *VarID,
392 SourceLocation Loc) {
393 return InitializedEntity(VarID, FieldType, Loc);
396 /// Create the entity for a compound literal initializer.
397 static InitializedEntity InitializeCompoundLiteralInit(TypeSourceInfo *TSI) {
398 InitializedEntity Result(EK_CompoundLiteralInit, SourceLocation(),
400 Result.TypeInfo = TSI;
404 /// Determine the kind of initialization.
405 EntityKind getKind() const { return Kind; }
407 /// Retrieve the parent of the entity being initialized, when
408 /// the initialization itself is occurring within the context of a
409 /// larger initialization.
410 const InitializedEntity *getParent() const { return Parent; }
412 /// Retrieve type being initialized.
413 QualType getType() const { return Type; }
415 /// Retrieve complete type-source information for the object being
416 /// constructed, if known.
417 TypeSourceInfo *getTypeSourceInfo() const {
418 if (Kind == EK_Temporary || Kind == EK_CompoundLiteralInit)
424 /// Retrieve the name of the entity being initialized.
425 DeclarationName getName() const;
427 /// Retrieve the variable, parameter, or field being
429 ValueDecl *getDecl() const;
431 /// Retrieve the ObjectiveC method being initialized.
432 ObjCMethodDecl *getMethodDecl() const { return MethodDecl; }
434 /// Determine whether this initialization allows the named return
435 /// value optimization, which also applies to thrown objects.
436 bool allowsNRVO() const;
438 bool isParameterKind() const {
439 return (getKind() == EK_Parameter ||
440 getKind() == EK_Parameter_CF_Audited);
443 /// Determine whether this initialization consumes the
445 bool isParameterConsumed() const {
446 assert(isParameterKind() && "Not a parameter");
447 return (Parameter & 1);
450 /// Retrieve the base specifier.
451 const CXXBaseSpecifier *getBaseSpecifier() const {
452 assert(getKind() == EK_Base && "Not a base specifier");
453 return reinterpret_cast<const CXXBaseSpecifier *>(Base & ~0x1);
456 /// Return whether the base is an inherited virtual base.
457 bool isInheritedVirtualBase() const {
458 assert(getKind() == EK_Base && "Not a base specifier");
462 /// Determine whether this is an array new with an unknown bound.
463 bool isVariableLengthArrayNew() const {
464 return getKind() == EK_New && dyn_cast_or_null<IncompleteArrayType>(
465 getType()->getAsArrayTypeUnsafe());
468 /// Is this the implicit initialization of a member of a class from
469 /// a defaulted constructor?
470 bool isImplicitMemberInitializer() const {
471 return getKind() == EK_Member && Variable.IsImplicitFieldInit;
474 /// Is this the default member initializer of a member (specified inside
475 /// the class definition)?
476 bool isDefaultMemberInitializer() const {
477 return getKind() == EK_Member && Variable.IsDefaultMemberInit;
480 /// Determine the location of the 'return' keyword when initializing
481 /// the result of a function call.
482 SourceLocation getReturnLoc() const {
483 assert(getKind() == EK_Result && "No 'return' location!");
484 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location);
487 /// Determine the location of the 'throw' keyword when initializing
488 /// an exception object.
489 SourceLocation getThrowLoc() const {
490 assert(getKind() == EK_Exception && "No 'throw' location!");
491 return SourceLocation::getFromRawEncoding(LocAndNRVO.Location);
494 /// If this is an array, vector, or complex number element, get the
496 unsigned getElementIndex() const {
497 assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
498 getKind() == EK_ComplexElement);
502 /// If this is already the initializer for an array or vector
503 /// element, sets the element index.
504 void setElementIndex(unsigned Index) {
505 assert(getKind() == EK_ArrayElement || getKind() == EK_VectorElement ||
506 getKind() == EK_ComplexElement);
510 /// For a lambda capture, return the capture's name.
511 StringRef getCapturedVarName() const {
512 assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
513 return Capture.VarID->getName();
516 /// Determine the location of the capture when initializing
517 /// field from a captured variable in a lambda.
518 SourceLocation getCaptureLoc() const {
519 assert(getKind() == EK_LambdaCapture && "Not a lambda capture!");
520 return SourceLocation::getFromRawEncoding(Capture.Location);
523 void setParameterCFAudited() {
524 Kind = EK_Parameter_CF_Audited;
527 unsigned allocateManglingNumber() const { return ++ManglingNumber; }
529 /// Dump a representation of the initialized entity to standard error,
530 /// for debugging purposes.
534 unsigned dumpImpl(raw_ostream &OS) const;
537 /// Describes the kind of initialization being performed, along with
538 /// location information for tokens related to the initialization (equal sign,
540 class InitializationKind {
542 /// The kind of initialization being performed.
544 /// Direct initialization
547 /// Direct list-initialization
550 /// Copy initialization
553 /// Default initialization
556 /// Value initialization
561 /// The context of the initialization.
566 /// Normal context, but allows explicit conversion functionss
569 /// Implicit context (value initialization)
572 /// Static cast context
575 /// C-style cast context
578 /// Functional cast context
582 /// The kind of initialization being performed.
585 /// The context of the initialization.
586 InitContext Context : 8;
588 /// The source locations involved in the initialization.
589 SourceLocation Locations[3];
591 InitializationKind(InitKind Kind, InitContext Context, SourceLocation Loc1,
592 SourceLocation Loc2, SourceLocation Loc3)
593 : Kind(Kind), Context(Context) {
600 /// Create a direct initialization.
601 static InitializationKind CreateDirect(SourceLocation InitLoc,
602 SourceLocation LParenLoc,
603 SourceLocation RParenLoc) {
604 return InitializationKind(IK_Direct, IC_Normal,
605 InitLoc, LParenLoc, RParenLoc);
608 static InitializationKind CreateDirectList(SourceLocation InitLoc) {
609 return InitializationKind(IK_DirectList, IC_Normal, InitLoc, InitLoc,
613 static InitializationKind CreateDirectList(SourceLocation InitLoc,
614 SourceLocation LBraceLoc,
615 SourceLocation RBraceLoc) {
616 return InitializationKind(IK_DirectList, IC_Normal, InitLoc, LBraceLoc,
620 /// Create a direct initialization due to a cast that isn't a C-style
621 /// or functional cast.
622 static InitializationKind CreateCast(SourceRange TypeRange) {
623 return InitializationKind(IK_Direct, IC_StaticCast, TypeRange.getBegin(),
624 TypeRange.getBegin(), TypeRange.getEnd());
627 /// Create a direct initialization for a C-style cast.
628 static InitializationKind CreateCStyleCast(SourceLocation StartLoc,
629 SourceRange TypeRange,
631 // C++ cast syntax doesn't permit init lists, but C compound literals are
633 return InitializationKind(InitList ? IK_DirectList : IK_Direct,
634 IC_CStyleCast, StartLoc, TypeRange.getBegin(),
638 /// Create a direct initialization for a functional cast.
639 static InitializationKind CreateFunctionalCast(SourceRange TypeRange,
641 return InitializationKind(InitList ? IK_DirectList : IK_Direct,
642 IC_FunctionalCast, TypeRange.getBegin(),
643 TypeRange.getBegin(), TypeRange.getEnd());
646 /// Create a copy initialization.
647 static InitializationKind CreateCopy(SourceLocation InitLoc,
648 SourceLocation EqualLoc,
649 bool AllowExplicitConvs = false) {
650 return InitializationKind(IK_Copy,
651 AllowExplicitConvs? IC_ExplicitConvs : IC_Normal,
652 InitLoc, EqualLoc, EqualLoc);
655 /// Create a default initialization.
656 static InitializationKind CreateDefault(SourceLocation InitLoc) {
657 return InitializationKind(IK_Default, IC_Normal, InitLoc, InitLoc, InitLoc);
660 /// Create a value initialization.
661 static InitializationKind CreateValue(SourceLocation InitLoc,
662 SourceLocation LParenLoc,
663 SourceLocation RParenLoc,
664 bool isImplicit = false) {
665 return InitializationKind(IK_Value, isImplicit ? IC_Implicit : IC_Normal,
666 InitLoc, LParenLoc, RParenLoc);
669 /// Create an initialization from an initializer (which, for direct
670 /// initialization from a parenthesized list, will be a ParenListExpr).
671 static InitializationKind CreateForInit(SourceLocation Loc, bool DirectInit,
673 if (!Init) return CreateDefault(Loc);
674 if (!DirectInit) return CreateCopy(Loc, Init->getLocStart());
675 if (isa<InitListExpr>(Init))
676 return CreateDirectList(Loc, Init->getLocStart(), Init->getLocEnd());
677 return CreateDirect(Loc, Init->getLocStart(), Init->getLocEnd());
680 /// Determine the initialization kind.
681 InitKind getKind() const {
685 /// Determine whether this initialization is an explicit cast.
686 bool isExplicitCast() const {
687 return Context >= IC_StaticCast;
690 /// Determine whether this initialization is a C-style cast.
691 bool isCStyleOrFunctionalCast() const {
692 return Context >= IC_CStyleCast;
695 /// Determine whether this is a C-style cast.
696 bool isCStyleCast() const {
697 return Context == IC_CStyleCast;
700 /// Determine whether this is a functional-style cast.
701 bool isFunctionalCast() const {
702 return Context == IC_FunctionalCast;
705 /// Determine whether this initialization is an implicit
706 /// value-initialization, e.g., as occurs during aggregate
708 bool isImplicitValueInit() const { return Context == IC_Implicit; }
710 /// Retrieve the location at which initialization is occurring.
711 SourceLocation getLocation() const { return Locations[0]; }
713 /// Retrieve the source range that covers the initialization.
714 SourceRange getRange() const {
715 return SourceRange(Locations[0], Locations[2]);
718 /// Retrieve the location of the equal sign for copy initialization
720 SourceLocation getEqualLoc() const {
721 assert(Kind == IK_Copy && "Only copy initialization has an '='");
725 bool isCopyInit() const { return Kind == IK_Copy; }
727 /// Retrieve whether this initialization allows the use of explicit
729 bool AllowExplicit() const { return !isCopyInit(); }
731 /// Retrieve whether this initialization allows the use of explicit
732 /// conversion functions when binding a reference. If the reference is the
733 /// first parameter in a copy or move constructor, such conversions are
734 /// permitted even though we are performing copy-initialization.
735 bool allowExplicitConversionFunctionsInRefBinding() const {
736 return !isCopyInit() || Context == IC_ExplicitConvs;
739 /// Determine whether this initialization has a source range containing the
740 /// locations of open and closing parentheses or braces.
741 bool hasParenOrBraceRange() const {
742 return Kind == IK_Direct || Kind == IK_Value || Kind == IK_DirectList;
745 /// Retrieve the source range containing the locations of the open
746 /// and closing parentheses or braces for value, direct, and direct list
748 SourceRange getParenOrBraceRange() const {
749 assert(hasParenOrBraceRange() && "Only direct, value, and direct-list "
750 "initialization have parentheses or "
752 return SourceRange(Locations[1], Locations[2]);
756 /// Describes the sequence of initializations required to initialize
757 /// a given object or reference with a set of arguments.
758 class InitializationSequence {
760 /// Describes the kind of initialization sequence computed.
762 /// A failed initialization sequence. The failure kind tells what
766 /// A dependent initialization, which could not be
767 /// type-checked due to the presence of dependent types or
768 /// dependently-typed expressions.
771 /// A normal sequence.
775 /// Describes the kind of a particular step in an initialization
778 /// Resolve the address of an overloaded function to a specific
779 /// function declaration.
780 SK_ResolveAddressOfOverloadedFunction,
782 /// Perform a derived-to-base cast, producing an rvalue.
783 SK_CastDerivedToBaseRValue,
785 /// Perform a derived-to-base cast, producing an xvalue.
786 SK_CastDerivedToBaseXValue,
788 /// Perform a derived-to-base cast, producing an lvalue.
789 SK_CastDerivedToBaseLValue,
791 /// Reference binding to an lvalue.
794 /// Reference binding to a temporary.
795 SK_BindReferenceToTemporary,
797 /// An optional copy of a temporary object to another
798 /// temporary object, which is permitted (but not required) by
799 /// C++98/03 but not C++0x.
800 SK_ExtraneousCopyToTemporary,
802 /// Direct-initialization from a reference-related object in the
803 /// final stage of class copy-initialization.
806 /// Perform a user-defined conversion, either via a conversion
807 /// function or via a constructor.
810 /// Perform a qualification conversion, producing an rvalue.
811 SK_QualificationConversionRValue,
813 /// Perform a qualification conversion, producing an xvalue.
814 SK_QualificationConversionXValue,
816 /// Perform a qualification conversion, producing an lvalue.
817 SK_QualificationConversionLValue,
819 /// Perform a conversion adding _Atomic to a type.
822 /// Perform a load from a glvalue, producing an rvalue.
825 /// Perform an implicit conversion sequence.
826 SK_ConversionSequence,
828 /// Perform an implicit conversion sequence without narrowing.
829 SK_ConversionSequenceNoNarrowing,
831 /// Perform list-initialization without a constructor.
832 SK_ListInitialization,
834 /// Unwrap the single-element initializer list for a reference.
837 /// Rewrap the single-element initializer list for a reference.
840 /// Perform initialization via a constructor.
841 SK_ConstructorInitialization,
843 /// Perform initialization via a constructor, taking arguments from
844 /// a single InitListExpr.
845 SK_ConstructorInitializationFromList,
847 /// Zero-initialize the object
848 SK_ZeroInitialization,
853 /// Initialization by string
856 /// An initialization that "converts" an Objective-C object
857 /// (not a point to an object) to another Objective-C object type.
858 SK_ObjCObjectConversion,
860 /// Array indexing for initialization by elementwise copy.
863 /// Array initialization by elementwise copy.
866 /// Array initialization (from an array rvalue).
869 /// Array initialization (from an array rvalue) as a GNU extension.
872 /// Array initialization from a parenthesized initializer list.
873 /// This is a GNU C++ extension.
874 SK_ParenthesizedArrayInit,
876 /// Pass an object by indirect copy-and-restore.
877 SK_PassByIndirectCopyRestore,
879 /// Pass an object by indirect restore.
880 SK_PassByIndirectRestore,
882 /// Produce an Objective-C object pointer.
883 SK_ProduceObjCObject,
885 /// Construct a std::initializer_list from an initializer list.
886 SK_StdInitializerList,
888 /// Perform initialization via a constructor taking a single
889 /// std::initializer_list argument.
890 SK_StdInitializerListConstructorCall,
892 /// Initialize an OpenCL sampler from an integer.
895 /// Initialize queue_t from 0.
898 /// Passing zero to a function where OpenCL event_t is expected.
902 /// A single step in the initialization sequence.
905 /// The kind of conversion or initialization step we are taking.
908 // The type that results from this initialization.
912 bool HadMultipleCandidates;
913 FunctionDecl *Function;
914 DeclAccessPair FoundDecl;
918 /// When Kind == SK_ResolvedOverloadedFunction or Kind ==
919 /// SK_UserConversion, the function that the expression should be
920 /// resolved to or the conversion function to call, respectively.
921 /// When Kind == SK_ConstructorInitialization or SK_ListConstruction,
922 /// the constructor to be called.
924 /// Always a FunctionDecl, plus a Boolean flag telling if it was
925 /// selected from an overloaded set having size greater than 1.
926 /// For conversion decls, the naming class is the source type.
927 /// For construct decls, the naming class is the target type.
930 /// When Kind = SK_ConversionSequence, the implicit conversion
932 ImplicitConversionSequence *ICS;
934 /// When Kind = SK_RewrapInitList, the syntactic form of the
936 InitListExpr *WrappingSyntacticList;
943 /// The kind of initialization sequence computed.
944 enum SequenceKind SequenceKind;
946 /// Steps taken by this initialization.
947 SmallVector<Step, 4> Steps;
950 /// Describes why initialization failed.
952 /// Too many initializers provided for a reference.
953 FK_TooManyInitsForReference,
955 /// Reference initialized from a parenthesized initializer list.
956 FK_ParenthesizedListInitForReference,
958 /// Array must be initialized with an initializer list.
959 FK_ArrayNeedsInitList,
961 /// Array must be initialized with an initializer list or a
963 FK_ArrayNeedsInitListOrStringLiteral,
965 /// Array must be initialized with an initializer list or a
966 /// wide string literal.
967 FK_ArrayNeedsInitListOrWideStringLiteral,
969 /// Initializing a wide char array with narrow string literal.
970 FK_NarrowStringIntoWideCharArray,
972 /// Initializing char array with wide string literal.
973 FK_WideStringIntoCharArray,
975 /// Initializing wide char array with incompatible wide string
977 FK_IncompatWideStringIntoWideChar,
979 /// Initializing char8_t array with plain string literal.
980 FK_PlainStringIntoUTF8Char,
982 /// Initializing char array with UTF-8 string literal.
983 FK_UTF8StringIntoPlainChar,
985 /// Array type mismatch.
986 FK_ArrayTypeMismatch,
988 /// Non-constant array initializer
989 FK_NonConstantArrayInit,
991 /// Cannot resolve the address of an overloaded function.
992 FK_AddressOfOverloadFailed,
994 /// Overloading due to reference initialization failed.
995 FK_ReferenceInitOverloadFailed,
997 /// Non-const lvalue reference binding to a temporary.
998 FK_NonConstLValueReferenceBindingToTemporary,
1000 /// Non-const lvalue reference binding to a bit-field.
1001 FK_NonConstLValueReferenceBindingToBitfield,
1003 /// Non-const lvalue reference binding to a vector element.
1004 FK_NonConstLValueReferenceBindingToVectorElement,
1006 /// Non-const lvalue reference binding to an lvalue of unrelated
1008 FK_NonConstLValueReferenceBindingToUnrelated,
1010 /// Rvalue reference binding to an lvalue.
1011 FK_RValueReferenceBindingToLValue,
1013 /// Reference binding drops qualifiers.
1014 FK_ReferenceInitDropsQualifiers,
1016 /// Reference binding failed.
1017 FK_ReferenceInitFailed,
1019 /// Implicit conversion failed.
1020 FK_ConversionFailed,
1022 /// Implicit conversion failed.
1023 FK_ConversionFromPropertyFailed,
1025 /// Too many initializers for scalar
1026 FK_TooManyInitsForScalar,
1028 /// Scalar initialized from a parenthesized initializer list.
1029 FK_ParenthesizedListInitForScalar,
1031 /// Reference initialization from an initializer list
1032 FK_ReferenceBindingToInitList,
1034 /// Initialization of some unused destination type with an
1035 /// initializer list.
1036 FK_InitListBadDestinationType,
1038 /// Overloading for a user-defined conversion failed.
1039 FK_UserConversionOverloadFailed,
1041 /// Overloading for initialization by constructor failed.
1042 FK_ConstructorOverloadFailed,
1044 /// Overloading for list-initialization by constructor failed.
1045 FK_ListConstructorOverloadFailed,
1047 /// Default-initialization of a 'const' object.
1048 FK_DefaultInitOfConst,
1050 /// Initialization of an incomplete type.
1053 /// Variable-length array must not have an initializer.
1054 FK_VariableLengthArrayHasInitializer,
1056 /// List initialization failed at some point.
1057 FK_ListInitializationFailed,
1059 /// Initializer has a placeholder type which cannot be
1060 /// resolved by initialization.
1063 /// Trying to take the address of a function that doesn't support
1064 /// having its address taken.
1065 FK_AddressOfUnaddressableFunction,
1067 /// List-copy-initialization chose an explicit constructor.
1068 FK_ExplicitConstructor,
1072 /// The reason why initialization failed.
1073 FailureKind Failure;
1075 /// The failed result of overload resolution.
1076 OverloadingResult FailedOverloadResult;
1078 /// The candidate set created when initialization failed.
1079 OverloadCandidateSet FailedCandidateSet;
1081 /// The incomplete type that caused a failure.
1082 QualType FailedIncompleteType;
1084 /// The fixit that needs to be applied to make this initialization
1086 std::string ZeroInitializationFixit;
1087 SourceLocation ZeroInitializationFixitLoc;
1090 /// Call for initializations are invalid but that would be valid
1091 /// zero initialzations if Fixit was applied.
1092 void SetZeroInitializationFixit(const std::string& Fixit, SourceLocation L) {
1093 ZeroInitializationFixit = Fixit;
1094 ZeroInitializationFixitLoc = L;
1098 /// Prints a follow-up note that highlights the location of
1099 /// the initialized entity, if it's remote.
1100 void PrintInitLocationNote(Sema &S, const InitializedEntity &Entity);
1103 /// Try to perform initialization of the given entity, creating a
1104 /// record of the steps required to perform the initialization.
1106 /// The generated initialization sequence will either contain enough
1107 /// information to diagnose
1109 /// \param S the semantic analysis object.
1111 /// \param Entity the entity being initialized.
1113 /// \param Kind the kind of initialization being performed.
1115 /// \param Args the argument(s) provided for initialization.
1117 /// \param TopLevelOfInitList true if we are initializing from an expression
1118 /// at the top level inside an initializer list. This disallows
1119 /// narrowing conversions in C++11 onwards.
1120 /// \param TreatUnavailableAsInvalid true if we want to treat unavailable
1122 InitializationSequence(Sema &S,
1123 const InitializedEntity &Entity,
1124 const InitializationKind &Kind,
1126 bool TopLevelOfInitList = false,
1127 bool TreatUnavailableAsInvalid = true);
1128 void InitializeFrom(Sema &S, const InitializedEntity &Entity,
1129 const InitializationKind &Kind, MultiExprArg Args,
1130 bool TopLevelOfInitList, bool TreatUnavailableAsInvalid);
1132 ~InitializationSequence();
1134 /// Perform the actual initialization of the given entity based on
1135 /// the computed initialization sequence.
1137 /// \param S the semantic analysis object.
1139 /// \param Entity the entity being initialized.
1141 /// \param Kind the kind of initialization being performed.
1143 /// \param Args the argument(s) provided for initialization, ownership of
1144 /// which is transferred into the routine.
1146 /// \param ResultType if non-NULL, will be set to the type of the
1147 /// initialized object, which is the type of the declaration in most
1148 /// cases. However, when the initialized object is a variable of
1149 /// incomplete array type and the initializer is an initializer
1150 /// list, this type will be set to the completed array type.
1152 /// \returns an expression that performs the actual object initialization, if
1153 /// the initialization is well-formed. Otherwise, emits diagnostics
1154 /// and returns an invalid expression.
1155 ExprResult Perform(Sema &S,
1156 const InitializedEntity &Entity,
1157 const InitializationKind &Kind,
1159 QualType *ResultType = nullptr);
1161 /// Diagnose an potentially-invalid initialization sequence.
1163 /// \returns true if the initialization sequence was ill-formed,
1164 /// false otherwise.
1165 bool Diagnose(Sema &S,
1166 const InitializedEntity &Entity,
1167 const InitializationKind &Kind,
1168 ArrayRef<Expr *> Args);
1170 /// Determine the kind of initialization sequence computed.
1171 enum SequenceKind getKind() const { return SequenceKind; }
1173 /// Set the kind of sequence computed.
1174 void setSequenceKind(enum SequenceKind SK) { SequenceKind = SK; }
1176 /// Determine whether the initialization sequence is valid.
1177 explicit operator bool() const { return !Failed(); }
1179 /// Determine whether the initialization sequence is invalid.
1180 bool Failed() const { return SequenceKind == FailedSequence; }
1182 using step_iterator = SmallVectorImpl<Step>::const_iterator;
1184 step_iterator step_begin() const { return Steps.begin(); }
1185 step_iterator step_end() const { return Steps.end(); }
1187 using step_range = llvm::iterator_range<step_iterator>;
1189 step_range steps() const { return {step_begin(), step_end()}; }
1191 /// Determine whether this initialization is a direct reference
1192 /// binding (C++ [dcl.init.ref]).
1193 bool isDirectReferenceBinding() const;
1195 /// Determine whether this initialization failed due to an ambiguity.
1196 bool isAmbiguous() const;
1198 /// Determine whether this initialization is direct call to a
1200 bool isConstructorInitialization() const;
1202 /// Returns whether the last step in this initialization sequence is a
1203 /// narrowing conversion, defined by C++0x [dcl.init.list]p7.
1205 /// If this function returns true, *isInitializerConstant will be set to
1206 /// describe whether *Initializer was a constant expression. If
1207 /// *isInitializerConstant is set to true, *ConstantValue will be set to the
1208 /// evaluated value of *Initializer.
1209 bool endsWithNarrowing(ASTContext &Ctx, const Expr *Initializer,
1210 bool *isInitializerConstant,
1211 APValue *ConstantValue) const;
1213 /// Add a new step in the initialization that resolves the address
1214 /// of an overloaded function to a specific function declaration.
1216 /// \param Function the function to which the overloaded function reference
1218 void AddAddressOverloadResolutionStep(FunctionDecl *Function,
1219 DeclAccessPair Found,
1220 bool HadMultipleCandidates);
1222 /// Add a new step in the initialization that performs a derived-to-
1225 /// \param BaseType the base type to which we will be casting.
1227 /// \param Category Indicates whether the result will be treated as an
1228 /// rvalue, an xvalue, or an lvalue.
1229 void AddDerivedToBaseCastStep(QualType BaseType,
1230 ExprValueKind Category);
1232 /// Add a new step binding a reference to an object.
1234 /// \param BindingTemporary True if we are binding a reference to a temporary
1235 /// object (thereby extending its lifetime); false if we are binding to an
1236 /// lvalue or an lvalue treated as an rvalue.
1237 void AddReferenceBindingStep(QualType T, bool BindingTemporary);
1239 /// Add a new step that makes an extraneous copy of the input
1240 /// to a temporary of the same class type.
1242 /// This extraneous copy only occurs during reference binding in
1243 /// C++98/03, where we are permitted (but not required) to introduce
1244 /// an extra copy. At a bare minimum, we must check that we could
1245 /// call the copy constructor, and produce a diagnostic if the copy
1246 /// constructor is inaccessible or no copy constructor matches.
1248 /// \param T The type of the temporary being created.
1249 void AddExtraneousCopyToTemporary(QualType T);
1251 /// Add a new step that makes a copy of the input to an object of
1252 /// the given type, as the final step in class copy-initialization.
1253 void AddFinalCopy(QualType T);
1255 /// Add a new step invoking a conversion function, which is either
1256 /// a constructor or a conversion function.
1257 void AddUserConversionStep(FunctionDecl *Function,
1258 DeclAccessPair FoundDecl,
1260 bool HadMultipleCandidates);
1262 /// Add a new step that performs a qualification conversion to the
1264 void AddQualificationConversionStep(QualType Ty,
1265 ExprValueKind Category);
1267 /// Add a new step that performs conversion from non-atomic to atomic
1269 void AddAtomicConversionStep(QualType Ty);
1271 /// Add a new step that performs a load of the given type.
1273 /// Although the term "LValueToRValue" is conventional, this applies to both
1274 /// lvalues and xvalues.
1275 void AddLValueToRValueStep(QualType Ty);
1277 /// Add a new step that applies an implicit conversion sequence.
1278 void AddConversionSequenceStep(const ImplicitConversionSequence &ICS,
1279 QualType T, bool TopLevelOfInitList = false);
1281 /// Add a list-initialization step.
1282 void AddListInitializationStep(QualType T);
1284 /// Add a constructor-initialization step.
1286 /// \param FromInitList The constructor call is syntactically an initializer
1288 /// \param AsInitList The constructor is called as an init list constructor.
1289 void AddConstructorInitializationStep(DeclAccessPair FoundDecl,
1290 CXXConstructorDecl *Constructor,
1292 bool HadMultipleCandidates,
1293 bool FromInitList, bool AsInitList);
1295 /// Add a zero-initialization step.
1296 void AddZeroInitializationStep(QualType T);
1298 /// Add a C assignment step.
1300 // FIXME: It isn't clear whether this should ever be needed;
1301 // ideally, we would handle everything needed in C in the common
1302 // path. However, that isn't the case yet.
1303 void AddCAssignmentStep(QualType T);
1305 /// Add a string init step.
1306 void AddStringInitStep(QualType T);
1308 /// Add an Objective-C object conversion step, which is
1310 void AddObjCObjectConversionStep(QualType T);
1312 /// Add an array initialization loop step.
1313 void AddArrayInitLoopStep(QualType T, QualType EltTy);
1315 /// Add an array initialization step.
1316 void AddArrayInitStep(QualType T, bool IsGNUExtension);
1318 /// Add a parenthesized array initialization step.
1319 void AddParenthesizedArrayInitStep(QualType T);
1321 /// Add a step to pass an object by indirect copy-restore.
1322 void AddPassByIndirectCopyRestoreStep(QualType T, bool shouldCopy);
1324 /// Add a step to "produce" an Objective-C object (by
1326 void AddProduceObjCObjectStep(QualType T);
1328 /// Add a step to construct a std::initializer_list object from an
1329 /// initializer list.
1330 void AddStdInitializerListConstructionStep(QualType T);
1332 /// Add a step to initialize an OpenCL sampler from an integer
1334 void AddOCLSamplerInitStep(QualType T);
1336 /// Add a step to initialize an OpenCL event_t from a NULL
1338 void AddOCLZeroEventStep(QualType T);
1340 /// Add a step to initialize an OpenCL queue_t from 0.
1341 void AddOCLZeroQueueStep(QualType T);
1343 /// Add steps to unwrap a initializer list for a reference around a
1344 /// single element and rewrap it at the end.
1345 void RewrapReferenceInitList(QualType T, InitListExpr *Syntactic);
1347 /// Note that this initialization sequence failed.
1348 void SetFailed(FailureKind Failure) {
1349 SequenceKind = FailedSequence;
1350 this->Failure = Failure;
1351 assert((Failure != FK_Incomplete || !FailedIncompleteType.isNull()) &&
1352 "Incomplete type failure requires a type!");
1355 /// Note that this initialization sequence failed due to failed
1356 /// overload resolution.
1357 void SetOverloadFailure(FailureKind Failure, OverloadingResult Result);
1359 /// Retrieve a reference to the candidate set when overload
1360 /// resolution fails.
1361 OverloadCandidateSet &getFailedCandidateSet() {
1362 return FailedCandidateSet;
1365 /// Get the overloading result, for when the initialization
1366 /// sequence failed due to a bad overload.
1367 OverloadingResult getFailedOverloadResult() const {
1368 return FailedOverloadResult;
1371 /// Note that this initialization sequence failed due to an
1372 /// incomplete type.
1373 void setIncompleteTypeFailure(QualType IncompleteType) {
1374 FailedIncompleteType = IncompleteType;
1375 SetFailed(FK_Incomplete);
1378 /// Determine why initialization failed.
1379 FailureKind getFailureKind() const {
1380 assert(Failed() && "Not an initialization failure!");
1384 /// Dump a representation of this initialization sequence to
1385 /// the given stream, for debugging purposes.
1386 void dump(raw_ostream &OS) const;
1388 /// Dump a representation of this initialization sequence to
1389 /// standard error, for debugging purposes.
1393 } // namespace clang
1395 #endif // LLVM_CLANG_SEMA_INITIALIZATION_H