1 //===--- Overload.h - C++ Overloading ---------------------------*- 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 defines the data structures and types used in C++
11 // overload resolution.
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CLANG_SEMA_OVERLOAD_H
16 #define LLVM_CLANG_SEMA_OVERLOAD_H
18 #include "clang/AST/Decl.h"
19 #include "clang/AST/DeclTemplate.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/AST/TemplateBase.h"
22 #include "clang/AST/Type.h"
23 #include "clang/AST/UnresolvedSet.h"
24 #include "clang/Sema/SemaFixItUtils.h"
25 #include "clang/Sema/TemplateDeduction.h"
26 #include "llvm/ADT/SmallPtrSet.h"
27 #include "llvm/ADT/SmallVector.h"
28 #include "llvm/Support/AlignOf.h"
29 #include "llvm/Support/Allocator.h"
33 class CXXConstructorDecl;
34 class CXXConversionDecl;
38 /// OverloadingResult - Capture the result of performing overload
40 enum OverloadingResult {
41 OR_Success, ///< Overload resolution succeeded.
42 OR_No_Viable_Function, ///< No viable function found.
43 OR_Ambiguous, ///< Ambiguous candidates found.
44 OR_Deleted ///< Succeeded, but refers to a deleted function.
47 enum OverloadCandidateDisplayKind {
48 /// Requests that all candidates be shown. Viable candidates will
52 /// Requests that only viable candidates be shown.
56 /// ImplicitConversionKind - The kind of implicit conversion used to
57 /// convert an argument to a parameter's type. The enumerator values
58 /// match with Table 9 of (C++ 13.3.3.1.1) and are listed such that
59 /// better conversion kinds have smaller values.
60 enum ImplicitConversionKind {
61 ICK_Identity = 0, ///< Identity conversion (no conversion)
62 ICK_Lvalue_To_Rvalue, ///< Lvalue-to-rvalue conversion (C++ 4.1)
63 ICK_Array_To_Pointer, ///< Array-to-pointer conversion (C++ 4.2)
64 ICK_Function_To_Pointer, ///< Function-to-pointer (C++ 4.3)
65 ICK_NoReturn_Adjustment, ///< Removal of noreturn from a type (Clang)
66 ICK_Qualification, ///< Qualification conversions (C++ 4.4)
67 ICK_Integral_Promotion, ///< Integral promotions (C++ 4.5)
68 ICK_Floating_Promotion, ///< Floating point promotions (C++ 4.6)
69 ICK_Complex_Promotion, ///< Complex promotions (Clang extension)
70 ICK_Integral_Conversion, ///< Integral conversions (C++ 4.7)
71 ICK_Floating_Conversion, ///< Floating point conversions (C++ 4.8)
72 ICK_Complex_Conversion, ///< Complex conversions (C99 6.3.1.6)
73 ICK_Floating_Integral, ///< Floating-integral conversions (C++ 4.9)
74 ICK_Pointer_Conversion, ///< Pointer conversions (C++ 4.10)
75 ICK_Pointer_Member, ///< Pointer-to-member conversions (C++ 4.11)
76 ICK_Boolean_Conversion, ///< Boolean conversions (C++ 4.12)
77 ICK_Compatible_Conversion, ///< Conversions between compatible types in C99
78 ICK_Derived_To_Base, ///< Derived-to-base (C++ [over.best.ics])
79 ICK_Vector_Conversion, ///< Vector conversions
80 ICK_Vector_Splat, ///< A vector splat from an arithmetic type
81 ICK_Complex_Real, ///< Complex-real conversions (C99 6.3.1.7)
82 ICK_Block_Pointer_Conversion, ///< Block Pointer conversions
83 ICK_TransparentUnionConversion, ///< Transparent Union Conversions
84 ICK_Writeback_Conversion, ///< Objective-C ARC writeback conversion
85 ICK_Zero_Event_Conversion, ///< Zero constant to event (OpenCL1.2 6.12.10)
86 ICK_C_Only_Conversion, ///< Conversions allowed in C, but not C++
87 ICK_Num_Conversion_Kinds, ///< The number of conversion kinds
90 /// ImplicitConversionRank - The rank of an implicit conversion
91 /// kind. The enumerator values match with Table 9 of (C++
92 /// 13.3.3.1.1) and are listed such that better conversion ranks
93 /// have smaller values.
94 enum ImplicitConversionRank {
95 ICR_Exact_Match = 0, ///< Exact Match
96 ICR_Promotion, ///< Promotion
97 ICR_Conversion, ///< Conversion
98 ICR_Complex_Real_Conversion, ///< Complex <-> Real conversion
99 ICR_Writeback_Conversion, ///< ObjC ARC writeback conversion
100 ICR_C_Conversion ///< Conversion only allowed in the C standard.
101 /// (e.g. void* to char*)
104 ImplicitConversionRank GetConversionRank(ImplicitConversionKind Kind);
106 /// NarrowingKind - The kind of narrowing conversion being performed by a
107 /// standard conversion sequence according to C++11 [dcl.init.list]p7.
109 /// Not a narrowing conversion.
112 /// A narrowing conversion by virtue of the source and destination types.
115 /// A narrowing conversion, because a constant expression got narrowed.
116 NK_Constant_Narrowing,
118 /// A narrowing conversion, because a non-constant-expression variable might
119 /// have got narrowed.
120 NK_Variable_Narrowing
123 /// StandardConversionSequence - represents a standard conversion
124 /// sequence (C++ 13.3.3.1.1). A standard conversion sequence
125 /// contains between zero and three conversions. If a particular
126 /// conversion is not needed, it will be set to the identity conversion
127 /// (ICK_Identity). Note that the three conversions are
128 /// specified as separate members (rather than in an array) so that
129 /// we can keep the size of a standard conversion sequence to a
131 class StandardConversionSequence {
133 /// First -- The first conversion can be an lvalue-to-rvalue
134 /// conversion, array-to-pointer conversion, or
135 /// function-to-pointer conversion.
136 ImplicitConversionKind First : 8;
138 /// Second - The second conversion can be an integral promotion,
139 /// floating point promotion, integral conversion, floating point
140 /// conversion, floating-integral conversion, pointer conversion,
141 /// pointer-to-member conversion, or boolean conversion.
142 ImplicitConversionKind Second : 8;
144 /// Third - The third conversion can be a qualification conversion.
145 ImplicitConversionKind Third : 8;
147 /// \brief Whether this is the deprecated conversion of a
148 /// string literal to a pointer to non-const character data
150 unsigned DeprecatedStringLiteralToCharPtr : 1;
152 /// \brief Whether the qualification conversion involves a change in the
153 /// Objective-C lifetime (for automatic reference counting).
154 unsigned QualificationIncludesObjCLifetime : 1;
156 /// IncompatibleObjC - Whether this is an Objective-C conversion
157 /// that we should warn about (if we actually use it).
158 unsigned IncompatibleObjC : 1;
160 /// ReferenceBinding - True when this is a reference binding
161 /// (C++ [over.ics.ref]).
162 unsigned ReferenceBinding : 1;
164 /// DirectBinding - True when this is a reference binding that is a
165 /// direct binding (C++ [dcl.init.ref]).
166 unsigned DirectBinding : 1;
168 /// \brief Whether this is an lvalue reference binding (otherwise, it's
169 /// an rvalue reference binding).
170 unsigned IsLvalueReference : 1;
172 /// \brief Whether we're binding to a function lvalue.
173 unsigned BindsToFunctionLvalue : 1;
175 /// \brief Whether we're binding to an rvalue.
176 unsigned BindsToRvalue : 1;
178 /// \brief Whether this binds an implicit object argument to a
179 /// non-static member function without a ref-qualifier.
180 unsigned BindsImplicitObjectArgumentWithoutRefQualifier : 1;
182 /// \brief Whether this binds a reference to an object with a different
183 /// Objective-C lifetime qualifier.
184 unsigned ObjCLifetimeConversionBinding : 1;
186 /// FromType - The type that this conversion is converting
187 /// from. This is an opaque pointer that can be translated into a
191 /// ToType - The types that this conversion is converting to in
192 /// each step. This is an opaque pointer that can be translated
196 /// CopyConstructor - The copy constructor that is used to perform
197 /// this conversion, when the conversion is actually just the
198 /// initialization of an object via copy constructor. Such
199 /// conversions are either identity conversions or derived-to-base
201 CXXConstructorDecl *CopyConstructor;
203 void setFromType(QualType T) { FromTypePtr = T.getAsOpaquePtr(); }
204 void setToType(unsigned Idx, QualType T) {
205 assert(Idx < 3 && "To type index is out of range");
206 ToTypePtrs[Idx] = T.getAsOpaquePtr();
208 void setAllToTypes(QualType T) {
209 ToTypePtrs[0] = T.getAsOpaquePtr();
210 ToTypePtrs[1] = ToTypePtrs[0];
211 ToTypePtrs[2] = ToTypePtrs[0];
214 QualType getFromType() const {
215 return QualType::getFromOpaquePtr(FromTypePtr);
217 QualType getToType(unsigned Idx) const {
218 assert(Idx < 3 && "To type index is out of range");
219 return QualType::getFromOpaquePtr(ToTypePtrs[Idx]);
222 void setAsIdentityConversion();
224 bool isIdentityConversion() const {
225 return Second == ICK_Identity && Third == ICK_Identity;
228 ImplicitConversionRank getRank() const;
229 NarrowingKind getNarrowingKind(ASTContext &Context, const Expr *Converted,
230 APValue &ConstantValue,
231 QualType &ConstantType) const;
232 bool isPointerConversionToBool() const;
233 bool isPointerConversionToVoidPointer(ASTContext& Context) const;
237 /// UserDefinedConversionSequence - Represents a user-defined
238 /// conversion sequence (C++ 13.3.3.1.2).
239 struct UserDefinedConversionSequence {
240 /// \brief Represents the standard conversion that occurs before
241 /// the actual user-defined conversion.
243 /// C++11 13.3.3.1.2p1:
244 /// If the user-defined conversion is specified by a constructor
245 /// (12.3.1), the initial standard conversion sequence converts
246 /// the source type to the type required by the argument of the
247 /// constructor. If the user-defined conversion is specified by
248 /// a conversion function (12.3.2), the initial standard
249 /// conversion sequence converts the source type to the implicit
250 /// object parameter of the conversion function.
251 StandardConversionSequence Before;
253 /// EllipsisConversion - When this is true, it means user-defined
254 /// conversion sequence starts with a ... (ellipsis) conversion, instead of
255 /// a standard conversion. In this case, 'Before' field must be ignored.
256 // FIXME. I much rather put this as the first field. But there seems to be
257 // a gcc code gen. bug which causes a crash in a test. Putting it here seems
258 // to work around the crash.
259 bool EllipsisConversion : 1;
261 /// HadMultipleCandidates - When this is true, it means that the
262 /// conversion function was resolved from an overloaded set having
263 /// size greater than 1.
264 bool HadMultipleCandidates : 1;
266 /// After - Represents the standard conversion that occurs after
267 /// the actual user-defined conversion.
268 StandardConversionSequence After;
270 /// ConversionFunction - The function that will perform the
271 /// user-defined conversion. Null if the conversion is an
272 /// aggregate initialization from an initializer list.
273 FunctionDecl* ConversionFunction;
275 /// \brief The declaration that we found via name lookup, which might be
276 /// the same as \c ConversionFunction or it might be a using declaration
277 /// that refers to \c ConversionFunction.
278 DeclAccessPair FoundConversionFunction;
283 /// Represents an ambiguous user-defined conversion sequence.
284 struct AmbiguousConversionSequence {
285 typedef SmallVector<FunctionDecl*, 4> ConversionSet;
289 char Buffer[sizeof(ConversionSet)];
291 QualType getFromType() const {
292 return QualType::getFromOpaquePtr(FromTypePtr);
294 QualType getToType() const {
295 return QualType::getFromOpaquePtr(ToTypePtr);
297 void setFromType(QualType T) { FromTypePtr = T.getAsOpaquePtr(); }
298 void setToType(QualType T) { ToTypePtr = T.getAsOpaquePtr(); }
300 ConversionSet &conversions() {
301 return *reinterpret_cast<ConversionSet*>(Buffer);
304 const ConversionSet &conversions() const {
305 return *reinterpret_cast<const ConversionSet*>(Buffer);
308 void addConversion(FunctionDecl *D) {
309 conversions().push_back(D);
312 typedef ConversionSet::iterator iterator;
313 iterator begin() { return conversions().begin(); }
314 iterator end() { return conversions().end(); }
316 typedef ConversionSet::const_iterator const_iterator;
317 const_iterator begin() const { return conversions().begin(); }
318 const_iterator end() const { return conversions().end(); }
322 void copyFrom(const AmbiguousConversionSequence &);
325 /// BadConversionSequence - Records information about an invalid
326 /// conversion sequence.
327 struct BadConversionSequence {
332 lvalue_ref_to_rvalue,
336 // This can be null, e.g. for implicit object arguments.
342 // The type we're converting from (an opaque QualType).
345 // The type we're converting to (an opaque QualType).
349 void init(FailureKind K, Expr *From, QualType To) {
350 init(K, From->getType(), To);
353 void init(FailureKind K, QualType From, QualType To) {
360 QualType getFromType() const { return QualType::getFromOpaquePtr(FromTy); }
361 QualType getToType() const { return QualType::getFromOpaquePtr(ToTy); }
363 void setFromExpr(Expr *E) {
365 setFromType(E->getType());
367 void setFromType(QualType T) { FromTy = T.getAsOpaquePtr(); }
368 void setToType(QualType T) { ToTy = T.getAsOpaquePtr(); }
371 /// ImplicitConversionSequence - Represents an implicit conversion
372 /// sequence, which may be a standard conversion sequence
373 /// (C++ 13.3.3.1.1), user-defined conversion sequence (C++ 13.3.3.1.2),
374 /// or an ellipsis conversion sequence (C++ 13.3.3.1.3).
375 class ImplicitConversionSequence {
377 /// Kind - The kind of implicit conversion sequence. BadConversion
378 /// specifies that there is no conversion from the source type to
379 /// the target type. AmbiguousConversion represents the unique
380 /// ambiguous conversion (C++0x [over.best.ics]p10).
382 StandardConversion = 0,
383 UserDefinedConversion,
391 Uninitialized = BadConversion + 1
394 /// ConversionKind - The kind of implicit conversion sequence.
395 unsigned ConversionKind : 30;
397 /// \brief Whether the target is really a std::initializer_list, and the
398 /// sequence only represents the worst element conversion.
399 bool StdInitializerListElement : 1;
401 void setKind(Kind K) {
407 if (ConversionKind == AmbiguousConversion) Ambiguous.destruct();
412 /// When ConversionKind == StandardConversion, provides the
413 /// details of the standard conversion sequence.
414 StandardConversionSequence Standard;
416 /// When ConversionKind == UserDefinedConversion, provides the
417 /// details of the user-defined conversion sequence.
418 UserDefinedConversionSequence UserDefined;
420 /// When ConversionKind == AmbiguousConversion, provides the
421 /// details of the ambiguous conversion.
422 AmbiguousConversionSequence Ambiguous;
424 /// When ConversionKind == BadConversion, provides the details
425 /// of the bad conversion.
426 BadConversionSequence Bad;
429 ImplicitConversionSequence()
430 : ConversionKind(Uninitialized), StdInitializerListElement(false)
432 ~ImplicitConversionSequence() {
435 ImplicitConversionSequence(const ImplicitConversionSequence &Other)
436 : ConversionKind(Other.ConversionKind),
437 StdInitializerListElement(Other.StdInitializerListElement)
439 switch (ConversionKind) {
440 case Uninitialized: break;
441 case StandardConversion: Standard = Other.Standard; break;
442 case UserDefinedConversion: UserDefined = Other.UserDefined; break;
443 case AmbiguousConversion: Ambiguous.copyFrom(Other.Ambiguous); break;
444 case EllipsisConversion: break;
445 case BadConversion: Bad = Other.Bad; break;
449 ImplicitConversionSequence &
450 operator=(const ImplicitConversionSequence &Other) {
452 new (this) ImplicitConversionSequence(Other);
456 Kind getKind() const {
457 assert(isInitialized() && "querying uninitialized conversion");
458 return Kind(ConversionKind);
461 /// \brief Return a ranking of the implicit conversion sequence
462 /// kind, where smaller ranks represent better conversion
465 /// In particular, this routine gives user-defined conversion
466 /// sequences and ambiguous conversion sequences the same rank,
467 /// per C++ [over.best.ics]p10.
468 unsigned getKindRank() const {
470 case StandardConversion:
473 case UserDefinedConversion:
474 case AmbiguousConversion:
477 case EllipsisConversion:
484 llvm_unreachable("Invalid ImplicitConversionSequence::Kind!");
487 bool isBad() const { return getKind() == BadConversion; }
488 bool isStandard() const { return getKind() == StandardConversion; }
489 bool isEllipsis() const { return getKind() == EllipsisConversion; }
490 bool isAmbiguous() const { return getKind() == AmbiguousConversion; }
491 bool isUserDefined() const { return getKind() == UserDefinedConversion; }
492 bool isFailure() const { return isBad() || isAmbiguous(); }
494 /// Determines whether this conversion sequence has been
495 /// initialized. Most operations should never need to query
496 /// uninitialized conversions and should assert as above.
497 bool isInitialized() const { return ConversionKind != Uninitialized; }
499 /// Sets this sequence as a bad conversion for an explicit argument.
500 void setBad(BadConversionSequence::FailureKind Failure,
501 Expr *FromExpr, QualType ToType) {
502 setKind(BadConversion);
503 Bad.init(Failure, FromExpr, ToType);
506 /// Sets this sequence as a bad conversion for an implicit argument.
507 void setBad(BadConversionSequence::FailureKind Failure,
508 QualType FromType, QualType ToType) {
509 setKind(BadConversion);
510 Bad.init(Failure, FromType, ToType);
513 void setStandard() { setKind(StandardConversion); }
514 void setEllipsis() { setKind(EllipsisConversion); }
515 void setUserDefined() { setKind(UserDefinedConversion); }
516 void setAmbiguous() {
517 if (ConversionKind == AmbiguousConversion) return;
518 ConversionKind = AmbiguousConversion;
519 Ambiguous.construct();
522 /// \brief Whether the target is really a std::initializer_list, and the
523 /// sequence only represents the worst element conversion.
524 bool isStdInitializerListElement() const {
525 return StdInitializerListElement;
528 void setStdInitializerListElement(bool V = true) {
529 StdInitializerListElement = V;
532 // The result of a comparison between implicit conversion
533 // sequences. Use Sema::CompareImplicitConversionSequences to
534 // actually perform the comparison.
537 Indistinguishable = 0,
541 void DiagnoseAmbiguousConversion(Sema &S,
542 SourceLocation CaretLoc,
543 const PartialDiagnostic &PDiag) const;
548 enum OverloadFailureKind {
549 ovl_fail_too_many_arguments,
550 ovl_fail_too_few_arguments,
551 ovl_fail_bad_conversion,
552 ovl_fail_bad_deduction,
554 /// This conversion candidate was not considered because it
555 /// duplicates the work of a trivial or derived-to-base
557 ovl_fail_trivial_conversion,
559 /// This conversion candidate was not considered because it is
560 /// an illegal instantiation of a constructor temploid: it is
561 /// callable with one argument, we only have one argument, and
562 /// its first parameter type is exactly the type of the class.
564 /// Defining such a constructor directly is illegal, and
565 /// template-argument deduction is supposed to ignore such
566 /// instantiations, but we can still get one with the right
567 /// kind of implicit instantiation.
568 ovl_fail_illegal_constructor,
570 /// This conversion candidate is not viable because its result
571 /// type is not implicitly convertible to the desired type.
572 ovl_fail_bad_final_conversion,
574 /// This conversion function template specialization candidate is not
575 /// viable because the final conversion was not an exact match.
576 ovl_fail_final_conversion_not_exact,
578 /// (CUDA) This candidate was not viable because the callee
579 /// was not accessible from the caller's target (i.e. host->device,
580 /// global->host, device->host).
583 /// This candidate function was not viable because an enable_if
584 /// attribute disabled it.
587 /// This candidate was not viable because its address could not be taken.
588 ovl_fail_addr_not_available
591 /// OverloadCandidate - A single candidate in an overload set (C++ 13.3).
592 struct OverloadCandidate {
593 /// Function - The actual function that this candidate
594 /// represents. When NULL, this is a built-in candidate
595 /// (C++ [over.oper]) or a surrogate for a conversion to a
596 /// function pointer or reference (C++ [over.call.object]).
597 FunctionDecl *Function;
599 /// FoundDecl - The original declaration that was looked up /
600 /// invented / otherwise found, together with its access.
601 /// Might be a UsingShadowDecl or a FunctionTemplateDecl.
602 DeclAccessPair FoundDecl;
604 // BuiltinTypes - Provides the return and parameter types of a
605 // built-in overload candidate. Only valid when Function is NULL.
608 QualType ParamTypes[3];
611 /// Surrogate - The conversion function for which this candidate
612 /// is a surrogate, but only if IsSurrogate is true.
613 CXXConversionDecl *Surrogate;
615 /// Conversions - The conversion sequences used to convert the
616 /// function arguments to the function parameters, the pointer points to a
617 /// fixed size array with NumConversions elements. The memory is owned by
618 /// the OverloadCandidateSet.
619 ImplicitConversionSequence *Conversions;
621 /// The FixIt hints which can be used to fix the Bad candidate.
622 ConversionFixItGenerator Fix;
624 /// NumConversions - The number of elements in the Conversions array.
625 unsigned NumConversions;
627 /// Viable - True to indicate that this overload candidate is viable.
630 /// IsSurrogate - True to indicate that this candidate is a
631 /// surrogate for a conversion to a function pointer or reference
632 /// (C++ [over.call.object]).
635 /// IgnoreObjectArgument - True to indicate that the first
636 /// argument's conversion, which for this function represents the
637 /// implicit object argument, should be ignored. This will be true
638 /// when the candidate is a static member function (where the
639 /// implicit object argument is just a placeholder) or a
640 /// non-static member function when the call doesn't have an
642 bool IgnoreObjectArgument;
644 /// FailureKind - The reason why this candidate is not viable.
645 /// Actually an OverloadFailureKind.
646 unsigned char FailureKind;
648 /// \brief The number of call arguments that were explicitly provided,
649 /// to be used while performing partial ordering of function templates.
650 unsigned ExplicitCallArguments;
653 DeductionFailureInfo DeductionFailure;
655 /// FinalConversion - For a conversion function (where Function is
656 /// a CXXConversionDecl), the standard conversion that occurs
657 /// after the call to the overload candidate to convert the result
658 /// of calling the conversion function to the required type.
659 StandardConversionSequence FinalConversion;
662 /// hasAmbiguousConversion - Returns whether this overload
663 /// candidate requires an ambiguous conversion or not.
664 bool hasAmbiguousConversion() const {
665 for (unsigned i = 0, e = NumConversions; i != e; ++i) {
666 if (!Conversions[i].isInitialized()) return false;
667 if (Conversions[i].isAmbiguous()) return true;
672 bool TryToFixBadConversion(unsigned Idx, Sema &S) {
673 bool CanFix = Fix.tryToFixConversion(
674 Conversions[Idx].Bad.FromExpr,
675 Conversions[Idx].Bad.getFromType(),
676 Conversions[Idx].Bad.getToType(), S);
678 // If at least one conversion fails, the candidate cannot be fixed.
685 unsigned getNumParams() const {
687 auto STy = Surrogate->getConversionType();
688 while (STy->isPointerType() || STy->isReferenceType())
689 STy = STy->getPointeeType();
690 return STy->getAs<FunctionProtoType>()->getNumParams();
693 return Function->getNumParams();
694 return ExplicitCallArguments;
698 /// OverloadCandidateSet - A set of overload candidates, used in C++
699 /// overload resolution (C++ 13.3).
700 class OverloadCandidateSet {
702 enum CandidateSetKind {
705 /// Lookup for candidates for a call using operator syntax. Candidates
706 /// that have no parameters of class type will be skipped unless there
707 /// is a parameter of (reference to) enum type and the corresponding
708 /// argument is of the same enum type.
713 SmallVector<OverloadCandidate, 16> Candidates;
714 llvm::SmallPtrSet<Decl *, 16> Functions;
716 // Allocator for OverloadCandidate::Conversions. We store the first few
717 // elements inline to avoid allocation for small sets.
718 llvm::BumpPtrAllocator ConversionSequenceAllocator;
721 CandidateSetKind Kind;
723 unsigned NumInlineSequences;
724 llvm::AlignedCharArray<llvm::AlignOf<ImplicitConversionSequence>::Alignment,
725 16 * sizeof(ImplicitConversionSequence)> InlineSpace;
727 OverloadCandidateSet(const OverloadCandidateSet &) = delete;
728 void operator=(const OverloadCandidateSet &) = delete;
730 void destroyCandidates();
733 OverloadCandidateSet(SourceLocation Loc, CandidateSetKind CSK)
734 : Loc(Loc), Kind(CSK), NumInlineSequences(0) {}
735 ~OverloadCandidateSet() { destroyCandidates(); }
737 SourceLocation getLocation() const { return Loc; }
738 CandidateSetKind getKind() const { return Kind; }
740 /// \brief Determine when this overload candidate will be new to the
742 bool isNewCandidate(Decl *F) {
743 return Functions.insert(F->getCanonicalDecl()).second;
746 /// \brief Clear out all of the candidates.
749 typedef SmallVectorImpl<OverloadCandidate>::iterator iterator;
750 iterator begin() { return Candidates.begin(); }
751 iterator end() { return Candidates.end(); }
753 size_t size() const { return Candidates.size(); }
754 bool empty() const { return Candidates.empty(); }
756 /// \brief Add a new candidate with NumConversions conversion sequence slots
757 /// to the overload set.
758 OverloadCandidate &addCandidate(unsigned NumConversions = 0) {
759 Candidates.push_back(OverloadCandidate());
760 OverloadCandidate &C = Candidates.back();
762 // Assign space from the inline array if there are enough free slots
764 if (NumConversions + NumInlineSequences <= 16) {
765 ImplicitConversionSequence *I =
766 (ImplicitConversionSequence *)InlineSpace.buffer;
767 C.Conversions = &I[NumInlineSequences];
768 NumInlineSequences += NumConversions;
770 // Otherwise get memory from the allocator.
771 C.Conversions = ConversionSequenceAllocator
772 .Allocate<ImplicitConversionSequence>(NumConversions);
775 // Construct the new objects.
776 for (unsigned i = 0; i != NumConversions; ++i)
777 new (&C.Conversions[i]) ImplicitConversionSequence();
779 C.NumConversions = NumConversions;
783 /// Find the best viable function on this overload set, if it exists.
784 OverloadingResult BestViableFunction(Sema &S, SourceLocation Loc,
785 OverloadCandidateSet::iterator& Best,
786 bool UserDefinedConversion = false);
788 void NoteCandidates(Sema &S,
789 OverloadCandidateDisplayKind OCD,
790 ArrayRef<Expr *> Args,
792 SourceLocation Loc = SourceLocation());
795 bool isBetterOverloadCandidate(Sema &S,
796 const OverloadCandidate& Cand1,
797 const OverloadCandidate& Cand2,
799 bool UserDefinedConversion = false);
800 } // end namespace clang
802 #endif // LLVM_CLANG_SEMA_OVERLOAD_H