1 //===--- SemaOverload.cpp - C++ Overloading -------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file provides Sema routines for C++ overloading.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/CXXInheritance.h"
15 #include "clang/AST/DeclObjC.h"
16 #include "clang/AST/DependenceFlags.h"
17 #include "clang/AST/Expr.h"
18 #include "clang/AST/ExprCXX.h"
19 #include "clang/AST/ExprObjC.h"
20 #include "clang/AST/TypeOrdering.h"
21 #include "clang/Basic/Diagnostic.h"
22 #include "clang/Basic/DiagnosticOptions.h"
23 #include "clang/Basic/PartialDiagnostic.h"
24 #include "clang/Basic/SourceManager.h"
25 #include "clang/Basic/TargetInfo.h"
26 #include "clang/Sema/Initialization.h"
27 #include "clang/Sema/Lookup.h"
28 #include "clang/Sema/Overload.h"
29 #include "clang/Sema/SemaInternal.h"
30 #include "clang/Sema/Template.h"
31 #include "clang/Sema/TemplateDeduction.h"
32 #include "llvm/ADT/DenseSet.h"
33 #include "llvm/ADT/Optional.h"
34 #include "llvm/ADT/STLExtras.h"
35 #include "llvm/ADT/SmallPtrSet.h"
36 #include "llvm/ADT/SmallString.h"
37 #include <algorithm>
38 #include <cstdlib>
39
40 using namespace clang;
41 using namespace sema;
42
43 using AllowedExplicit = Sema::AllowedExplicit;
44
functionHasPassObjectSizeParams(const FunctionDecl * FD)45 static bool functionHasPassObjectSizeParams(const FunctionDecl *FD) {
46 return llvm::any_of(FD->parameters(), [](const ParmVarDecl *P) {
47 return P->hasAttr<PassObjectSizeAttr>();
48 });
49 }
50
51 /// A convenience routine for creating a decayed reference to a function.
52 static ExprResult
CreateFunctionRefExpr(Sema & S,FunctionDecl * Fn,NamedDecl * FoundDecl,const Expr * Base,bool HadMultipleCandidates,SourceLocation Loc=SourceLocation (),const DeclarationNameLoc & LocInfo=DeclarationNameLoc ())53 CreateFunctionRefExpr(Sema &S, FunctionDecl *Fn, NamedDecl *FoundDecl,
54 const Expr *Base, bool HadMultipleCandidates,
55 SourceLocation Loc = SourceLocation(),
56 const DeclarationNameLoc &LocInfo = DeclarationNameLoc()){
57 if (S.DiagnoseUseOfDecl(FoundDecl, Loc))
58 return ExprError();
59 // If FoundDecl is different from Fn (such as if one is a template
60 // and the other a specialization), make sure DiagnoseUseOfDecl is
61 // called on both.
62 // FIXME: This would be more comprehensively addressed by modifying
63 // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
64 // being used.
65 if (FoundDecl != Fn && S.DiagnoseUseOfDecl(Fn, Loc))
66 return ExprError();
67 DeclRefExpr *DRE = new (S.Context)
68 DeclRefExpr(S.Context, Fn, false, Fn->getType(), VK_LValue, Loc, LocInfo);
69 if (HadMultipleCandidates)
70 DRE->setHadMultipleCandidates(true);
71
72 S.MarkDeclRefReferenced(DRE, Base);
73 if (auto *FPT = DRE->getType()->getAs<FunctionProtoType>()) {
74 if (isUnresolvedExceptionSpec(FPT->getExceptionSpecType())) {
75 S.ResolveExceptionSpec(Loc, FPT);
76 DRE->setType(Fn->getType());
77 }
78 }
79 return S.ImpCastExprToType(DRE, S.Context.getPointerType(DRE->getType()),
80 CK_FunctionToPointerDecay);
81 }
82
83 static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
84 bool InOverloadResolution,
85 StandardConversionSequence &SCS,
86 bool CStyle,
87 bool AllowObjCWritebackConversion);
88
89 static bool IsTransparentUnionStandardConversion(Sema &S, Expr* From,
90 QualType &ToType,
91 bool InOverloadResolution,
92 StandardConversionSequence &SCS,
93 bool CStyle);
94 static OverloadingResult
95 IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
96 UserDefinedConversionSequence& User,
97 OverloadCandidateSet& Conversions,
98 AllowedExplicit AllowExplicit,
99 bool AllowObjCConversionOnExplicit);
100
101 static ImplicitConversionSequence::CompareKind
102 CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
103 const StandardConversionSequence& SCS1,
104 const StandardConversionSequence& SCS2);
105
106 static ImplicitConversionSequence::CompareKind
107 CompareQualificationConversions(Sema &S,
108 const StandardConversionSequence& SCS1,
109 const StandardConversionSequence& SCS2);
110
111 static ImplicitConversionSequence::CompareKind
112 CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
113 const StandardConversionSequence& SCS1,
114 const StandardConversionSequence& SCS2);
115
116 /// GetConversionRank - Retrieve the implicit conversion rank
117 /// corresponding to the given implicit conversion kind.
GetConversionRank(ImplicitConversionKind Kind)118 ImplicitConversionRank clang::GetConversionRank(ImplicitConversionKind Kind) {
119 static const ImplicitConversionRank
120 Rank[(int)ICK_Num_Conversion_Kinds] = {
121 ICR_Exact_Match,
122 ICR_Exact_Match,
123 ICR_Exact_Match,
124 ICR_Exact_Match,
125 ICR_Exact_Match,
126 ICR_Exact_Match,
127 ICR_Promotion,
128 ICR_Promotion,
129 ICR_Promotion,
130 ICR_Conversion,
131 ICR_Conversion,
132 ICR_Conversion,
133 ICR_Conversion,
134 ICR_Conversion,
135 ICR_Conversion,
136 ICR_Conversion,
137 ICR_Conversion,
138 ICR_Conversion,
139 ICR_Conversion,
140 ICR_Conversion,
141 ICR_OCL_Scalar_Widening,
142 ICR_Complex_Real_Conversion,
143 ICR_Conversion,
144 ICR_Conversion,
145 ICR_Writeback_Conversion,
146 ICR_Exact_Match, // NOTE(gbiv): This may not be completely right --
147 // it was omitted by the patch that added
148 // ICK_Zero_Event_Conversion
149 ICR_C_Conversion,
150 ICR_C_Conversion_Extension
151 };
152 return Rank[(int)Kind];
153 }
154
155 /// GetImplicitConversionName - Return the name of this kind of
156 /// implicit conversion.
GetImplicitConversionName(ImplicitConversionKind Kind)157 static const char* GetImplicitConversionName(ImplicitConversionKind Kind) {
158 static const char* const Name[(int)ICK_Num_Conversion_Kinds] = {
159 "No conversion",
160 "Lvalue-to-rvalue",
161 "Array-to-pointer",
162 "Function-to-pointer",
163 "Function pointer conversion",
164 "Qualification",
165 "Integral promotion",
166 "Floating point promotion",
167 "Complex promotion",
168 "Integral conversion",
169 "Floating conversion",
170 "Complex conversion",
171 "Floating-integral conversion",
172 "Pointer conversion",
173 "Pointer-to-member conversion",
174 "Boolean conversion",
175 "Compatible-types conversion",
176 "Derived-to-base conversion",
177 "Vector conversion",
178 "SVE Vector conversion",
179 "Vector splat",
180 "Complex-real conversion",
181 "Block Pointer conversion",
182 "Transparent Union Conversion",
183 "Writeback conversion",
184 "OpenCL Zero Event Conversion",
185 "C specific type conversion",
186 "Incompatible pointer conversion"
187 };
188 return Name[Kind];
189 }
190
191 /// StandardConversionSequence - Set the standard conversion
192 /// sequence to the identity conversion.
setAsIdentityConversion()193 void StandardConversionSequence::setAsIdentityConversion() {
194 First = ICK_Identity;
195 Second = ICK_Identity;
196 Third = ICK_Identity;
197 DeprecatedStringLiteralToCharPtr = false;
198 QualificationIncludesObjCLifetime = false;
199 ReferenceBinding = false;
200 DirectBinding = false;
201 IsLvalueReference = true;
202 BindsToFunctionLvalue = false;
203 BindsToRvalue = false;
204 BindsImplicitObjectArgumentWithoutRefQualifier = false;
205 ObjCLifetimeConversionBinding = false;
206 CopyConstructor = nullptr;
207 }
208
209 /// getRank - Retrieve the rank of this standard conversion sequence
210 /// (C++ 13.3.3.1.1p3). The rank is the largest rank of each of the
211 /// implicit conversions.
getRank() const212 ImplicitConversionRank StandardConversionSequence::getRank() const {
213 ImplicitConversionRank Rank = ICR_Exact_Match;
214 if (GetConversionRank(First) > Rank)
215 Rank = GetConversionRank(First);
216 if (GetConversionRank(Second) > Rank)
217 Rank = GetConversionRank(Second);
218 if (GetConversionRank(Third) > Rank)
219 Rank = GetConversionRank(Third);
220 return Rank;
221 }
222
223 /// isPointerConversionToBool - Determines whether this conversion is
224 /// a conversion of a pointer or pointer-to-member to bool. This is
225 /// used as part of the ranking of standard conversion sequences
226 /// (C++ 13.3.3.2p4).
isPointerConversionToBool() const227 bool StandardConversionSequence::isPointerConversionToBool() const {
228 // Note that FromType has not necessarily been transformed by the
229 // array-to-pointer or function-to-pointer implicit conversions, so
230 // check for their presence as well as checking whether FromType is
231 // a pointer.
232 if (getToType(1)->isBooleanType() &&
233 (getFromType()->isPointerType() ||
234 getFromType()->isMemberPointerType() ||
235 getFromType()->isObjCObjectPointerType() ||
236 getFromType()->isBlockPointerType() ||
237 First == ICK_Array_To_Pointer || First == ICK_Function_To_Pointer))
238 return true;
239
240 return false;
241 }
242
243 /// isPointerConversionToVoidPointer - Determines whether this
244 /// conversion is a conversion of a pointer to a void pointer. This is
245 /// used as part of the ranking of standard conversion sequences (C++
246 /// 13.3.3.2p4).
247 bool
248 StandardConversionSequence::
isPointerConversionToVoidPointer(ASTContext & Context) const249 isPointerConversionToVoidPointer(ASTContext& Context) const {
250 QualType FromType = getFromType();
251 QualType ToType = getToType(1);
252
253 // Note that FromType has not necessarily been transformed by the
254 // array-to-pointer implicit conversion, so check for its presence
255 // and redo the conversion to get a pointer.
256 if (First == ICK_Array_To_Pointer)
257 FromType = Context.getArrayDecayedType(FromType);
258
259 if (Second == ICK_Pointer_Conversion && FromType->isAnyPointerType())
260 if (const PointerType* ToPtrType = ToType->getAs<PointerType>())
261 return ToPtrType->getPointeeType()->isVoidType();
262
263 return false;
264 }
265
266 /// Skip any implicit casts which could be either part of a narrowing conversion
267 /// or after one in an implicit conversion.
IgnoreNarrowingConversion(ASTContext & Ctx,const Expr * Converted)268 static const Expr *IgnoreNarrowingConversion(ASTContext &Ctx,
269 const Expr *Converted) {
270 // We can have cleanups wrapping the converted expression; these need to be
271 // preserved so that destructors run if necessary.
272 if (auto *EWC = dyn_cast<ExprWithCleanups>(Converted)) {
273 Expr *Inner =
274 const_cast<Expr *>(IgnoreNarrowingConversion(Ctx, EWC->getSubExpr()));
275 return ExprWithCleanups::Create(Ctx, Inner, EWC->cleanupsHaveSideEffects(),
276 EWC->getObjects());
277 }
278
279 while (auto *ICE = dyn_cast<ImplicitCastExpr>(Converted)) {
280 switch (ICE->getCastKind()) {
281 case CK_NoOp:
282 case CK_IntegralCast:
283 case CK_IntegralToBoolean:
284 case CK_IntegralToFloating:
285 case CK_BooleanToSignedIntegral:
286 case CK_FloatingToIntegral:
287 case CK_FloatingToBoolean:
288 case CK_FloatingCast:
289 Converted = ICE->getSubExpr();
290 continue;
291
292 default:
293 return Converted;
294 }
295 }
296
297 return Converted;
298 }
299
300 /// Check if this standard conversion sequence represents a narrowing
301 /// conversion, according to C++11 [dcl.init.list]p7.
302 ///
303 /// \param Ctx The AST context.
304 /// \param Converted The result of applying this standard conversion sequence.
305 /// \param ConstantValue If this is an NK_Constant_Narrowing conversion, the
306 /// value of the expression prior to the narrowing conversion.
307 /// \param ConstantType If this is an NK_Constant_Narrowing conversion, the
308 /// type of the expression prior to the narrowing conversion.
309 /// \param IgnoreFloatToIntegralConversion If true type-narrowing conversions
310 /// from floating point types to integral types should be ignored.
getNarrowingKind(ASTContext & Ctx,const Expr * Converted,APValue & ConstantValue,QualType & ConstantType,bool IgnoreFloatToIntegralConversion) const311 NarrowingKind StandardConversionSequence::getNarrowingKind(
312 ASTContext &Ctx, const Expr *Converted, APValue &ConstantValue,
313 QualType &ConstantType, bool IgnoreFloatToIntegralConversion) const {
314 assert(Ctx.getLangOpts().CPlusPlus && "narrowing check outside C++");
315
316 // C++11 [dcl.init.list]p7:
317 // A narrowing conversion is an implicit conversion ...
318 QualType FromType = getToType(0);
319 QualType ToType = getToType(1);
320
321 // A conversion to an enumeration type is narrowing if the conversion to
322 // the underlying type is narrowing. This only arises for expressions of
323 // the form 'Enum{init}'.
324 if (auto *ET = ToType->getAs<EnumType>())
325 ToType = ET->getDecl()->getIntegerType();
326
327 switch (Second) {
328 // 'bool' is an integral type; dispatch to the right place to handle it.
329 case ICK_Boolean_Conversion:
330 if (FromType->isRealFloatingType())
331 goto FloatingIntegralConversion;
332 if (FromType->isIntegralOrUnscopedEnumerationType())
333 goto IntegralConversion;
334 // -- from a pointer type or pointer-to-member type to bool, or
335 return NK_Type_Narrowing;
336
337 // -- from a floating-point type to an integer type, or
338 //
339 // -- from an integer type or unscoped enumeration type to a floating-point
340 // type, except where the source is a constant expression and the actual
341 // value after conversion will fit into the target type and will produce
342 // the original value when converted back to the original type, or
343 case ICK_Floating_Integral:
344 FloatingIntegralConversion:
345 if (FromType->isRealFloatingType() && ToType->isIntegralType(Ctx)) {
346 return NK_Type_Narrowing;
347 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
348 ToType->isRealFloatingType()) {
349 if (IgnoreFloatToIntegralConversion)
350 return NK_Not_Narrowing;
351 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
352 assert(Initializer && "Unknown conversion expression");
353
354 // If it's value-dependent, we can't tell whether it's narrowing.
355 if (Initializer->isValueDependent())
356 return NK_Dependent_Narrowing;
357
358 if (Optional<llvm::APSInt> IntConstantValue =
359 Initializer->getIntegerConstantExpr(Ctx)) {
360 // Convert the integer to the floating type.
361 llvm::APFloat Result(Ctx.getFloatTypeSemantics(ToType));
362 Result.convertFromAPInt(*IntConstantValue, IntConstantValue->isSigned(),
363 llvm::APFloat::rmNearestTiesToEven);
364 // And back.
365 llvm::APSInt ConvertedValue = *IntConstantValue;
366 bool ignored;
367 Result.convertToInteger(ConvertedValue,
368 llvm::APFloat::rmTowardZero, &ignored);
369 // If the resulting value is different, this was a narrowing conversion.
370 if (*IntConstantValue != ConvertedValue) {
371 ConstantValue = APValue(*IntConstantValue);
372 ConstantType = Initializer->getType();
373 return NK_Constant_Narrowing;
374 }
375 } else {
376 // Variables are always narrowings.
377 return NK_Variable_Narrowing;
378 }
379 }
380 return NK_Not_Narrowing;
381
382 // -- from long double to double or float, or from double to float, except
383 // where the source is a constant expression and the actual value after
384 // conversion is within the range of values that can be represented (even
385 // if it cannot be represented exactly), or
386 case ICK_Floating_Conversion:
387 if (FromType->isRealFloatingType() && ToType->isRealFloatingType() &&
388 Ctx.getFloatingTypeOrder(FromType, ToType) == 1) {
389 // FromType is larger than ToType.
390 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
391
392 // If it's value-dependent, we can't tell whether it's narrowing.
393 if (Initializer->isValueDependent())
394 return NK_Dependent_Narrowing;
395
396 if (Initializer->isCXX11ConstantExpr(Ctx, &ConstantValue)) {
397 // Constant!
398 assert(ConstantValue.isFloat());
399 llvm::APFloat FloatVal = ConstantValue.getFloat();
400 // Convert the source value into the target type.
401 bool ignored;
402 llvm::APFloat::opStatus ConvertStatus = FloatVal.convert(
403 Ctx.getFloatTypeSemantics(ToType),
404 llvm::APFloat::rmNearestTiesToEven, &ignored);
405 // If there was no overflow, the source value is within the range of
406 // values that can be represented.
407 if (ConvertStatus & llvm::APFloat::opOverflow) {
408 ConstantType = Initializer->getType();
409 return NK_Constant_Narrowing;
410 }
411 } else {
412 return NK_Variable_Narrowing;
413 }
414 }
415 return NK_Not_Narrowing;
416
417 // -- from an integer type or unscoped enumeration type to an integer type
418 // that cannot represent all the values of the original type, except where
419 // the source is a constant expression and the actual value after
420 // conversion will fit into the target type and will produce the original
421 // value when converted back to the original type.
422 case ICK_Integral_Conversion:
423 IntegralConversion: {
424 assert(FromType->isIntegralOrUnscopedEnumerationType());
425 assert(ToType->isIntegralOrUnscopedEnumerationType());
426 const bool FromSigned = FromType->isSignedIntegerOrEnumerationType();
427 const unsigned FromWidth = Ctx.getIntWidth(FromType);
428 const bool ToSigned = ToType->isSignedIntegerOrEnumerationType();
429 const unsigned ToWidth = Ctx.getIntWidth(ToType);
430
431 if (FromWidth > ToWidth ||
432 (FromWidth == ToWidth && FromSigned != ToSigned) ||
433 (FromSigned && !ToSigned)) {
434 // Not all values of FromType can be represented in ToType.
435 const Expr *Initializer = IgnoreNarrowingConversion(Ctx, Converted);
436
437 // If it's value-dependent, we can't tell whether it's narrowing.
438 if (Initializer->isValueDependent())
439 return NK_Dependent_Narrowing;
440
441 Optional<llvm::APSInt> OptInitializerValue;
442 if (!(OptInitializerValue = Initializer->getIntegerConstantExpr(Ctx))) {
443 // Such conversions on variables are always narrowing.
444 return NK_Variable_Narrowing;
445 }
446 llvm::APSInt &InitializerValue = *OptInitializerValue;
447 bool Narrowing = false;
448 if (FromWidth < ToWidth) {
449 // Negative -> unsigned is narrowing. Otherwise, more bits is never
450 // narrowing.
451 if (InitializerValue.isSigned() && InitializerValue.isNegative())
452 Narrowing = true;
453 } else {
454 // Add a bit to the InitializerValue so we don't have to worry about
455 // signed vs. unsigned comparisons.
456 InitializerValue = InitializerValue.extend(
457 InitializerValue.getBitWidth() + 1);
458 // Convert the initializer to and from the target width and signed-ness.
459 llvm::APSInt ConvertedValue = InitializerValue;
460 ConvertedValue = ConvertedValue.trunc(ToWidth);
461 ConvertedValue.setIsSigned(ToSigned);
462 ConvertedValue = ConvertedValue.extend(InitializerValue.getBitWidth());
463 ConvertedValue.setIsSigned(InitializerValue.isSigned());
464 // If the result is different, this was a narrowing conversion.
465 if (ConvertedValue != InitializerValue)
466 Narrowing = true;
467 }
468 if (Narrowing) {
469 ConstantType = Initializer->getType();
470 ConstantValue = APValue(InitializerValue);
471 return NK_Constant_Narrowing;
472 }
473 }
474 return NK_Not_Narrowing;
475 }
476
477 default:
478 // Other kinds of conversions are not narrowings.
479 return NK_Not_Narrowing;
480 }
481 }
482
483 /// dump - Print this standard conversion sequence to standard
484 /// error. Useful for debugging overloading issues.
dump() const485 LLVM_DUMP_METHOD void StandardConversionSequence::dump() const {
486 raw_ostream &OS = llvm::errs();
487 bool PrintedSomething = false;
488 if (First != ICK_Identity) {
489 OS << GetImplicitConversionName(First);
490 PrintedSomething = true;
491 }
492
493 if (Second != ICK_Identity) {
494 if (PrintedSomething) {
495 OS << " -> ";
496 }
497 OS << GetImplicitConversionName(Second);
498
499 if (CopyConstructor) {
500 OS << " (by copy constructor)";
501 } else if (DirectBinding) {
502 OS << " (direct reference binding)";
503 } else if (ReferenceBinding) {
504 OS << " (reference binding)";
505 }
506 PrintedSomething = true;
507 }
508
509 if (Third != ICK_Identity) {
510 if (PrintedSomething) {
511 OS << " -> ";
512 }
513 OS << GetImplicitConversionName(Third);
514 PrintedSomething = true;
515 }
516
517 if (!PrintedSomething) {
518 OS << "No conversions required";
519 }
520 }
521
522 /// dump - Print this user-defined conversion sequence to standard
523 /// error. Useful for debugging overloading issues.
dump() const524 void UserDefinedConversionSequence::dump() const {
525 raw_ostream &OS = llvm::errs();
526 if (Before.First || Before.Second || Before.Third) {
527 Before.dump();
528 OS << " -> ";
529 }
530 if (ConversionFunction)
531 OS << '\'' << *ConversionFunction << '\'';
532 else
533 OS << "aggregate initialization";
534 if (After.First || After.Second || After.Third) {
535 OS << " -> ";
536 After.dump();
537 }
538 }
539
540 /// dump - Print this implicit conversion sequence to standard
541 /// error. Useful for debugging overloading issues.
dump() const542 void ImplicitConversionSequence::dump() const {
543 raw_ostream &OS = llvm::errs();
544 if (hasInitializerListContainerType())
545 OS << "Worst list element conversion: ";
546 switch (ConversionKind) {
547 case StandardConversion:
548 OS << "Standard conversion: ";
549 Standard.dump();
550 break;
551 case UserDefinedConversion:
552 OS << "User-defined conversion: ";
553 UserDefined.dump();
554 break;
555 case EllipsisConversion:
556 OS << "Ellipsis conversion";
557 break;
558 case AmbiguousConversion:
559 OS << "Ambiguous conversion";
560 break;
561 case BadConversion:
562 OS << "Bad conversion";
563 break;
564 }
565
566 OS << "\n";
567 }
568
construct()569 void AmbiguousConversionSequence::construct() {
570 new (&conversions()) ConversionSet();
571 }
572
destruct()573 void AmbiguousConversionSequence::destruct() {
574 conversions().~ConversionSet();
575 }
576
577 void
copyFrom(const AmbiguousConversionSequence & O)578 AmbiguousConversionSequence::copyFrom(const AmbiguousConversionSequence &O) {
579 FromTypePtr = O.FromTypePtr;
580 ToTypePtr = O.ToTypePtr;
581 new (&conversions()) ConversionSet(O.conversions());
582 }
583
584 namespace {
585 // Structure used by DeductionFailureInfo to store
586 // template argument information.
587 struct DFIArguments {
588 TemplateArgument FirstArg;
589 TemplateArgument SecondArg;
590 };
591 // Structure used by DeductionFailureInfo to store
592 // template parameter and template argument information.
593 struct DFIParamWithArguments : DFIArguments {
594 TemplateParameter Param;
595 };
596 // Structure used by DeductionFailureInfo to store template argument
597 // information and the index of the problematic call argument.
598 struct DFIDeducedMismatchArgs : DFIArguments {
599 TemplateArgumentList *TemplateArgs;
600 unsigned CallArgIndex;
601 };
602 // Structure used by DeductionFailureInfo to store information about
603 // unsatisfied constraints.
604 struct CNSInfo {
605 TemplateArgumentList *TemplateArgs;
606 ConstraintSatisfaction Satisfaction;
607 };
608 }
609
610 /// Convert from Sema's representation of template deduction information
611 /// to the form used in overload-candidate information.
612 DeductionFailureInfo
MakeDeductionFailureInfo(ASTContext & Context,Sema::TemplateDeductionResult TDK,TemplateDeductionInfo & Info)613 clang::MakeDeductionFailureInfo(ASTContext &Context,
614 Sema::TemplateDeductionResult TDK,
615 TemplateDeductionInfo &Info) {
616 DeductionFailureInfo Result;
617 Result.Result = static_cast<unsigned>(TDK);
618 Result.HasDiagnostic = false;
619 switch (TDK) {
620 case Sema::TDK_Invalid:
621 case Sema::TDK_InstantiationDepth:
622 case Sema::TDK_TooManyArguments:
623 case Sema::TDK_TooFewArguments:
624 case Sema::TDK_MiscellaneousDeductionFailure:
625 case Sema::TDK_CUDATargetMismatch:
626 Result.Data = nullptr;
627 break;
628
629 case Sema::TDK_Incomplete:
630 case Sema::TDK_InvalidExplicitArguments:
631 Result.Data = Info.Param.getOpaqueValue();
632 break;
633
634 case Sema::TDK_DeducedMismatch:
635 case Sema::TDK_DeducedMismatchNested: {
636 // FIXME: Should allocate from normal heap so that we can free this later.
637 auto *Saved = new (Context) DFIDeducedMismatchArgs;
638 Saved->FirstArg = Info.FirstArg;
639 Saved->SecondArg = Info.SecondArg;
640 Saved->TemplateArgs = Info.take();
641 Saved->CallArgIndex = Info.CallArgIndex;
642 Result.Data = Saved;
643 break;
644 }
645
646 case Sema::TDK_NonDeducedMismatch: {
647 // FIXME: Should allocate from normal heap so that we can free this later.
648 DFIArguments *Saved = new (Context) DFIArguments;
649 Saved->FirstArg = Info.FirstArg;
650 Saved->SecondArg = Info.SecondArg;
651 Result.Data = Saved;
652 break;
653 }
654
655 case Sema::TDK_IncompletePack:
656 // FIXME: It's slightly wasteful to allocate two TemplateArguments for this.
657 case Sema::TDK_Inconsistent:
658 case Sema::TDK_Underqualified: {
659 // FIXME: Should allocate from normal heap so that we can free this later.
660 DFIParamWithArguments *Saved = new (Context) DFIParamWithArguments;
661 Saved->Param = Info.Param;
662 Saved->FirstArg = Info.FirstArg;
663 Saved->SecondArg = Info.SecondArg;
664 Result.Data = Saved;
665 break;
666 }
667
668 case Sema::TDK_SubstitutionFailure:
669 Result.Data = Info.take();
670 if (Info.hasSFINAEDiagnostic()) {
671 PartialDiagnosticAt *Diag = new (Result.Diagnostic) PartialDiagnosticAt(
672 SourceLocation(), PartialDiagnostic::NullDiagnostic());
673 Info.takeSFINAEDiagnostic(*Diag);
674 Result.HasDiagnostic = true;
675 }
676 break;
677
678 case Sema::TDK_ConstraintsNotSatisfied: {
679 CNSInfo *Saved = new (Context) CNSInfo;
680 Saved->TemplateArgs = Info.take();
681 Saved->Satisfaction = Info.AssociatedConstraintsSatisfaction;
682 Result.Data = Saved;
683 break;
684 }
685
686 case Sema::TDK_Success:
687 case Sema::TDK_NonDependentConversionFailure:
688 llvm_unreachable("not a deduction failure");
689 }
690
691 return Result;
692 }
693
Destroy()694 void DeductionFailureInfo::Destroy() {
695 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
696 case Sema::TDK_Success:
697 case Sema::TDK_Invalid:
698 case Sema::TDK_InstantiationDepth:
699 case Sema::TDK_Incomplete:
700 case Sema::TDK_TooManyArguments:
701 case Sema::TDK_TooFewArguments:
702 case Sema::TDK_InvalidExplicitArguments:
703 case Sema::TDK_CUDATargetMismatch:
704 case Sema::TDK_NonDependentConversionFailure:
705 break;
706
707 case Sema::TDK_IncompletePack:
708 case Sema::TDK_Inconsistent:
709 case Sema::TDK_Underqualified:
710 case Sema::TDK_DeducedMismatch:
711 case Sema::TDK_DeducedMismatchNested:
712 case Sema::TDK_NonDeducedMismatch:
713 // FIXME: Destroy the data?
714 Data = nullptr;
715 break;
716
717 case Sema::TDK_SubstitutionFailure:
718 // FIXME: Destroy the template argument list?
719 Data = nullptr;
720 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
721 Diag->~PartialDiagnosticAt();
722 HasDiagnostic = false;
723 }
724 break;
725
726 case Sema::TDK_ConstraintsNotSatisfied:
727 // FIXME: Destroy the template argument list?
728 Data = nullptr;
729 if (PartialDiagnosticAt *Diag = getSFINAEDiagnostic()) {
730 Diag->~PartialDiagnosticAt();
731 HasDiagnostic = false;
732 }
733 break;
734
735 // Unhandled
736 case Sema::TDK_MiscellaneousDeductionFailure:
737 break;
738 }
739 }
740
getSFINAEDiagnostic()741 PartialDiagnosticAt *DeductionFailureInfo::getSFINAEDiagnostic() {
742 if (HasDiagnostic)
743 return static_cast<PartialDiagnosticAt*>(static_cast<void*>(Diagnostic));
744 return nullptr;
745 }
746
getTemplateParameter()747 TemplateParameter DeductionFailureInfo::getTemplateParameter() {
748 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
749 case Sema::TDK_Success:
750 case Sema::TDK_Invalid:
751 case Sema::TDK_InstantiationDepth:
752 case Sema::TDK_TooManyArguments:
753 case Sema::TDK_TooFewArguments:
754 case Sema::TDK_SubstitutionFailure:
755 case Sema::TDK_DeducedMismatch:
756 case Sema::TDK_DeducedMismatchNested:
757 case Sema::TDK_NonDeducedMismatch:
758 case Sema::TDK_CUDATargetMismatch:
759 case Sema::TDK_NonDependentConversionFailure:
760 case Sema::TDK_ConstraintsNotSatisfied:
761 return TemplateParameter();
762
763 case Sema::TDK_Incomplete:
764 case Sema::TDK_InvalidExplicitArguments:
765 return TemplateParameter::getFromOpaqueValue(Data);
766
767 case Sema::TDK_IncompletePack:
768 case Sema::TDK_Inconsistent:
769 case Sema::TDK_Underqualified:
770 return static_cast<DFIParamWithArguments*>(Data)->Param;
771
772 // Unhandled
773 case Sema::TDK_MiscellaneousDeductionFailure:
774 break;
775 }
776
777 return TemplateParameter();
778 }
779
getTemplateArgumentList()780 TemplateArgumentList *DeductionFailureInfo::getTemplateArgumentList() {
781 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
782 case Sema::TDK_Success:
783 case Sema::TDK_Invalid:
784 case Sema::TDK_InstantiationDepth:
785 case Sema::TDK_TooManyArguments:
786 case Sema::TDK_TooFewArguments:
787 case Sema::TDK_Incomplete:
788 case Sema::TDK_IncompletePack:
789 case Sema::TDK_InvalidExplicitArguments:
790 case Sema::TDK_Inconsistent:
791 case Sema::TDK_Underqualified:
792 case Sema::TDK_NonDeducedMismatch:
793 case Sema::TDK_CUDATargetMismatch:
794 case Sema::TDK_NonDependentConversionFailure:
795 return nullptr;
796
797 case Sema::TDK_DeducedMismatch:
798 case Sema::TDK_DeducedMismatchNested:
799 return static_cast<DFIDeducedMismatchArgs*>(Data)->TemplateArgs;
800
801 case Sema::TDK_SubstitutionFailure:
802 return static_cast<TemplateArgumentList*>(Data);
803
804 case Sema::TDK_ConstraintsNotSatisfied:
805 return static_cast<CNSInfo*>(Data)->TemplateArgs;
806
807 // Unhandled
808 case Sema::TDK_MiscellaneousDeductionFailure:
809 break;
810 }
811
812 return nullptr;
813 }
814
getFirstArg()815 const TemplateArgument *DeductionFailureInfo::getFirstArg() {
816 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
817 case Sema::TDK_Success:
818 case Sema::TDK_Invalid:
819 case Sema::TDK_InstantiationDepth:
820 case Sema::TDK_Incomplete:
821 case Sema::TDK_TooManyArguments:
822 case Sema::TDK_TooFewArguments:
823 case Sema::TDK_InvalidExplicitArguments:
824 case Sema::TDK_SubstitutionFailure:
825 case Sema::TDK_CUDATargetMismatch:
826 case Sema::TDK_NonDependentConversionFailure:
827 case Sema::TDK_ConstraintsNotSatisfied:
828 return nullptr;
829
830 case Sema::TDK_IncompletePack:
831 case Sema::TDK_Inconsistent:
832 case Sema::TDK_Underqualified:
833 case Sema::TDK_DeducedMismatch:
834 case Sema::TDK_DeducedMismatchNested:
835 case Sema::TDK_NonDeducedMismatch:
836 return &static_cast<DFIArguments*>(Data)->FirstArg;
837
838 // Unhandled
839 case Sema::TDK_MiscellaneousDeductionFailure:
840 break;
841 }
842
843 return nullptr;
844 }
845
getSecondArg()846 const TemplateArgument *DeductionFailureInfo::getSecondArg() {
847 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
848 case Sema::TDK_Success:
849 case Sema::TDK_Invalid:
850 case Sema::TDK_InstantiationDepth:
851 case Sema::TDK_Incomplete:
852 case Sema::TDK_IncompletePack:
853 case Sema::TDK_TooManyArguments:
854 case Sema::TDK_TooFewArguments:
855 case Sema::TDK_InvalidExplicitArguments:
856 case Sema::TDK_SubstitutionFailure:
857 case Sema::TDK_CUDATargetMismatch:
858 case Sema::TDK_NonDependentConversionFailure:
859 case Sema::TDK_ConstraintsNotSatisfied:
860 return nullptr;
861
862 case Sema::TDK_Inconsistent:
863 case Sema::TDK_Underqualified:
864 case Sema::TDK_DeducedMismatch:
865 case Sema::TDK_DeducedMismatchNested:
866 case Sema::TDK_NonDeducedMismatch:
867 return &static_cast<DFIArguments*>(Data)->SecondArg;
868
869 // Unhandled
870 case Sema::TDK_MiscellaneousDeductionFailure:
871 break;
872 }
873
874 return nullptr;
875 }
876
getCallArgIndex()877 llvm::Optional<unsigned> DeductionFailureInfo::getCallArgIndex() {
878 switch (static_cast<Sema::TemplateDeductionResult>(Result)) {
879 case Sema::TDK_DeducedMismatch:
880 case Sema::TDK_DeducedMismatchNested:
881 return static_cast<DFIDeducedMismatchArgs*>(Data)->CallArgIndex;
882
883 default:
884 return llvm::None;
885 }
886 }
887
shouldAddReversed(OverloadedOperatorKind Op)888 bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
889 OverloadedOperatorKind Op) {
890 if (!AllowRewrittenCandidates)
891 return false;
892 return Op == OO_EqualEqual || Op == OO_Spaceship;
893 }
894
shouldAddReversed(ASTContext & Ctx,const FunctionDecl * FD)895 bool OverloadCandidateSet::OperatorRewriteInfo::shouldAddReversed(
896 ASTContext &Ctx, const FunctionDecl *FD) {
897 if (!shouldAddReversed(FD->getDeclName().getCXXOverloadedOperator()))
898 return false;
899 // Don't bother adding a reversed candidate that can never be a better
900 // match than the non-reversed version.
901 return FD->getNumParams() != 2 ||
902 !Ctx.hasSameUnqualifiedType(FD->getParamDecl(0)->getType(),
903 FD->getParamDecl(1)->getType()) ||
904 FD->hasAttr<EnableIfAttr>();
905 }
906
destroyCandidates()907 void OverloadCandidateSet::destroyCandidates() {
908 for (iterator i = begin(), e = end(); i != e; ++i) {
909 for (auto &C : i->Conversions)
910 C.~ImplicitConversionSequence();
911 if (!i->Viable && i->FailureKind == ovl_fail_bad_deduction)
912 i->DeductionFailure.Destroy();
913 }
914 }
915
clear(CandidateSetKind CSK)916 void OverloadCandidateSet::clear(CandidateSetKind CSK) {
917 destroyCandidates();
918 SlabAllocator.Reset();
919 NumInlineBytesUsed = 0;
920 Candidates.clear();
921 Functions.clear();
922 Kind = CSK;
923 }
924
925 namespace {
926 class UnbridgedCastsSet {
927 struct Entry {
928 Expr **Addr;
929 Expr *Saved;
930 };
931 SmallVector<Entry, 2> Entries;
932
933 public:
save(Sema & S,Expr * & E)934 void save(Sema &S, Expr *&E) {
935 assert(E->hasPlaceholderType(BuiltinType::ARCUnbridgedCast));
936 Entry entry = { &E, E };
937 Entries.push_back(entry);
938 E = S.stripARCUnbridgedCast(E);
939 }
940
restore()941 void restore() {
942 for (SmallVectorImpl<Entry>::iterator
943 i = Entries.begin(), e = Entries.end(); i != e; ++i)
944 *i->Addr = i->Saved;
945 }
946 };
947 }
948
949 /// checkPlaceholderForOverload - Do any interesting placeholder-like
950 /// preprocessing on the given expression.
951 ///
952 /// \param unbridgedCasts a collection to which to add unbridged casts;
953 /// without this, they will be immediately diagnosed as errors
954 ///
955 /// Return true on unrecoverable error.
956 static bool
checkPlaceholderForOverload(Sema & S,Expr * & E,UnbridgedCastsSet * unbridgedCasts=nullptr)957 checkPlaceholderForOverload(Sema &S, Expr *&E,
958 UnbridgedCastsSet *unbridgedCasts = nullptr) {
959 if (const BuiltinType *placeholder = E->getType()->getAsPlaceholderType()) {
960 // We can't handle overloaded expressions here because overload
961 // resolution might reasonably tweak them.
962 if (placeholder->getKind() == BuiltinType::Overload) return false;
963
964 // If the context potentially accepts unbridged ARC casts, strip
965 // the unbridged cast and add it to the collection for later restoration.
966 if (placeholder->getKind() == BuiltinType::ARCUnbridgedCast &&
967 unbridgedCasts) {
968 unbridgedCasts->save(S, E);
969 return false;
970 }
971
972 // Go ahead and check everything else.
973 ExprResult result = S.CheckPlaceholderExpr(E);
974 if (result.isInvalid())
975 return true;
976
977 E = result.get();
978 return false;
979 }
980
981 // Nothing to do.
982 return false;
983 }
984
985 /// checkArgPlaceholdersForOverload - Check a set of call operands for
986 /// placeholders.
checkArgPlaceholdersForOverload(Sema & S,MultiExprArg Args,UnbridgedCastsSet & unbridged)987 static bool checkArgPlaceholdersForOverload(Sema &S,
988 MultiExprArg Args,
989 UnbridgedCastsSet &unbridged) {
990 for (unsigned i = 0, e = Args.size(); i != e; ++i)
991 if (checkPlaceholderForOverload(S, Args[i], &unbridged))
992 return true;
993
994 return false;
995 }
996
997 /// Determine whether the given New declaration is an overload of the
998 /// declarations in Old. This routine returns Ovl_Match or Ovl_NonFunction if
999 /// New and Old cannot be overloaded, e.g., if New has the same signature as
1000 /// some function in Old (C++ 1.3.10) or if the Old declarations aren't
1001 /// functions (or function templates) at all. When it does return Ovl_Match or
1002 /// Ovl_NonFunction, MatchedDecl will point to the decl that New cannot be
1003 /// overloaded with. This decl may be a UsingShadowDecl on top of the underlying
1004 /// declaration.
1005 ///
1006 /// Example: Given the following input:
1007 ///
1008 /// void f(int, float); // #1
1009 /// void f(int, int); // #2
1010 /// int f(int, int); // #3
1011 ///
1012 /// When we process #1, there is no previous declaration of "f", so IsOverload
1013 /// will not be used.
1014 ///
1015 /// When we process #2, Old contains only the FunctionDecl for #1. By comparing
1016 /// the parameter types, we see that #1 and #2 are overloaded (since they have
1017 /// different signatures), so this routine returns Ovl_Overload; MatchedDecl is
1018 /// unchanged.
1019 ///
1020 /// When we process #3, Old is an overload set containing #1 and #2. We compare
1021 /// the signatures of #3 to #1 (they're overloaded, so we do nothing) and then
1022 /// #3 to #2. Since the signatures of #3 and #2 are identical (return types of
1023 /// functions are not part of the signature), IsOverload returns Ovl_Match and
1024 /// MatchedDecl will be set to point to the FunctionDecl for #2.
1025 ///
1026 /// 'NewIsUsingShadowDecl' indicates that 'New' is being introduced into a class
1027 /// by a using declaration. The rules for whether to hide shadow declarations
1028 /// ignore some properties which otherwise figure into a function template's
1029 /// signature.
1030 Sema::OverloadKind
CheckOverload(Scope * S,FunctionDecl * New,const LookupResult & Old,NamedDecl * & Match,bool NewIsUsingDecl)1031 Sema::CheckOverload(Scope *S, FunctionDecl *New, const LookupResult &Old,
1032 NamedDecl *&Match, bool NewIsUsingDecl) {
1033 for (LookupResult::iterator I = Old.begin(), E = Old.end();
1034 I != E; ++I) {
1035 NamedDecl *OldD = *I;
1036
1037 bool OldIsUsingDecl = false;
1038 if (isa<UsingShadowDecl>(OldD)) {
1039 OldIsUsingDecl = true;
1040
1041 // We can always introduce two using declarations into the same
1042 // context, even if they have identical signatures.
1043 if (NewIsUsingDecl) continue;
1044
1045 OldD = cast<UsingShadowDecl>(OldD)->getTargetDecl();
1046 }
1047
1048 // A using-declaration does not conflict with another declaration
1049 // if one of them is hidden.
1050 if ((OldIsUsingDecl || NewIsUsingDecl) && !isVisible(*I))
1051 continue;
1052
1053 // If either declaration was introduced by a using declaration,
1054 // we'll need to use slightly different rules for matching.
1055 // Essentially, these rules are the normal rules, except that
1056 // function templates hide function templates with different
1057 // return types or template parameter lists.
1058 bool UseMemberUsingDeclRules =
1059 (OldIsUsingDecl || NewIsUsingDecl) && CurContext->isRecord() &&
1060 !New->getFriendObjectKind();
1061
1062 if (FunctionDecl *OldF = OldD->getAsFunction()) {
1063 if (!IsOverload(New, OldF, UseMemberUsingDeclRules)) {
1064 if (UseMemberUsingDeclRules && OldIsUsingDecl) {
1065 HideUsingShadowDecl(S, cast<UsingShadowDecl>(*I));
1066 continue;
1067 }
1068
1069 if (!isa<FunctionTemplateDecl>(OldD) &&
1070 !shouldLinkPossiblyHiddenDecl(*I, New))
1071 continue;
1072
1073 Match = *I;
1074 return Ovl_Match;
1075 }
1076
1077 // Builtins that have custom typechecking or have a reference should
1078 // not be overloadable or redeclarable.
1079 if (!getASTContext().canBuiltinBeRedeclared(OldF)) {
1080 Match = *I;
1081 return Ovl_NonFunction;
1082 }
1083 } else if (isa<UsingDecl>(OldD) || isa<UsingPackDecl>(OldD)) {
1084 // We can overload with these, which can show up when doing
1085 // redeclaration checks for UsingDecls.
1086 assert(Old.getLookupKind() == LookupUsingDeclName);
1087 } else if (isa<TagDecl>(OldD)) {
1088 // We can always overload with tags by hiding them.
1089 } else if (auto *UUD = dyn_cast<UnresolvedUsingValueDecl>(OldD)) {
1090 // Optimistically assume that an unresolved using decl will
1091 // overload; if it doesn't, we'll have to diagnose during
1092 // template instantiation.
1093 //
1094 // Exception: if the scope is dependent and this is not a class
1095 // member, the using declaration can only introduce an enumerator.
1096 if (UUD->getQualifier()->isDependent() && !UUD->isCXXClassMember()) {
1097 Match = *I;
1098 return Ovl_NonFunction;
1099 }
1100 } else {
1101 // (C++ 13p1):
1102 // Only function declarations can be overloaded; object and type
1103 // declarations cannot be overloaded.
1104 Match = *I;
1105 return Ovl_NonFunction;
1106 }
1107 }
1108
1109 // C++ [temp.friend]p1:
1110 // For a friend function declaration that is not a template declaration:
1111 // -- if the name of the friend is a qualified or unqualified template-id,
1112 // [...], otherwise
1113 // -- if the name of the friend is a qualified-id and a matching
1114 // non-template function is found in the specified class or namespace,
1115 // the friend declaration refers to that function, otherwise,
1116 // -- if the name of the friend is a qualified-id and a matching function
1117 // template is found in the specified class or namespace, the friend
1118 // declaration refers to the deduced specialization of that function
1119 // template, otherwise
1120 // -- the name shall be an unqualified-id [...]
1121 // If we get here for a qualified friend declaration, we've just reached the
1122 // third bullet. If the type of the friend is dependent, skip this lookup
1123 // until instantiation.
1124 if (New->getFriendObjectKind() && New->getQualifier() &&
1125 !New->getDescribedFunctionTemplate() &&
1126 !New->getDependentSpecializationInfo() &&
1127 !New->getType()->isDependentType()) {
1128 LookupResult TemplateSpecResult(LookupResult::Temporary, Old);
1129 TemplateSpecResult.addAllDecls(Old);
1130 if (CheckFunctionTemplateSpecialization(New, nullptr, TemplateSpecResult,
1131 /*QualifiedFriend*/true)) {
1132 New->setInvalidDecl();
1133 return Ovl_Overload;
1134 }
1135
1136 Match = TemplateSpecResult.getAsSingle<FunctionDecl>();
1137 return Ovl_Match;
1138 }
1139
1140 return Ovl_Overload;
1141 }
1142
IsOverload(FunctionDecl * New,FunctionDecl * Old,bool UseMemberUsingDeclRules,bool ConsiderCudaAttrs,bool ConsiderRequiresClauses)1143 bool Sema::IsOverload(FunctionDecl *New, FunctionDecl *Old,
1144 bool UseMemberUsingDeclRules, bool ConsiderCudaAttrs,
1145 bool ConsiderRequiresClauses) {
1146 // C++ [basic.start.main]p2: This function shall not be overloaded.
1147 if (New->isMain())
1148 return false;
1149
1150 // MSVCRT user defined entry points cannot be overloaded.
1151 if (New->isMSVCRTEntryPoint())
1152 return false;
1153
1154 FunctionTemplateDecl *OldTemplate = Old->getDescribedFunctionTemplate();
1155 FunctionTemplateDecl *NewTemplate = New->getDescribedFunctionTemplate();
1156
1157 // C++ [temp.fct]p2:
1158 // A function template can be overloaded with other function templates
1159 // and with normal (non-template) functions.
1160 if ((OldTemplate == nullptr) != (NewTemplate == nullptr))
1161 return true;
1162
1163 // Is the function New an overload of the function Old?
1164 QualType OldQType = Context.getCanonicalType(Old->getType());
1165 QualType NewQType = Context.getCanonicalType(New->getType());
1166
1167 // Compare the signatures (C++ 1.3.10) of the two functions to
1168 // determine whether they are overloads. If we find any mismatch
1169 // in the signature, they are overloads.
1170
1171 // If either of these functions is a K&R-style function (no
1172 // prototype), then we consider them to have matching signatures.
1173 if (isa<FunctionNoProtoType>(OldQType.getTypePtr()) ||
1174 isa<FunctionNoProtoType>(NewQType.getTypePtr()))
1175 return false;
1176
1177 const FunctionProtoType *OldType = cast<FunctionProtoType>(OldQType);
1178 const FunctionProtoType *NewType = cast<FunctionProtoType>(NewQType);
1179
1180 // The signature of a function includes the types of its
1181 // parameters (C++ 1.3.10), which includes the presence or absence
1182 // of the ellipsis; see C++ DR 357).
1183 if (OldQType != NewQType &&
1184 (OldType->getNumParams() != NewType->getNumParams() ||
1185 OldType->isVariadic() != NewType->isVariadic() ||
1186 !FunctionParamTypesAreEqual(OldType, NewType)))
1187 return true;
1188
1189 // C++ [temp.over.link]p4:
1190 // The signature of a function template consists of its function
1191 // signature, its return type and its template parameter list. The names
1192 // of the template parameters are significant only for establishing the
1193 // relationship between the template parameters and the rest of the
1194 // signature.
1195 //
1196 // We check the return type and template parameter lists for function
1197 // templates first; the remaining checks follow.
1198 //
1199 // However, we don't consider either of these when deciding whether
1200 // a member introduced by a shadow declaration is hidden.
1201 if (!UseMemberUsingDeclRules && NewTemplate &&
1202 (!TemplateParameterListsAreEqual(NewTemplate->getTemplateParameters(),
1203 OldTemplate->getTemplateParameters(),
1204 false, TPL_TemplateMatch) ||
1205 !Context.hasSameType(Old->getDeclaredReturnType(),
1206 New->getDeclaredReturnType())))
1207 return true;
1208
1209 // If the function is a class member, its signature includes the
1210 // cv-qualifiers (if any) and ref-qualifier (if any) on the function itself.
1211 //
1212 // As part of this, also check whether one of the member functions
1213 // is static, in which case they are not overloads (C++
1214 // 13.1p2). While not part of the definition of the signature,
1215 // this check is important to determine whether these functions
1216 // can be overloaded.
1217 CXXMethodDecl *OldMethod = dyn_cast<CXXMethodDecl>(Old);
1218 CXXMethodDecl *NewMethod = dyn_cast<CXXMethodDecl>(New);
1219 if (OldMethod && NewMethod &&
1220 !OldMethod->isStatic() && !NewMethod->isStatic()) {
1221 if (OldMethod->getRefQualifier() != NewMethod->getRefQualifier()) {
1222 if (!UseMemberUsingDeclRules &&
1223 (OldMethod->getRefQualifier() == RQ_None ||
1224 NewMethod->getRefQualifier() == RQ_None)) {
1225 // C++0x [over.load]p2:
1226 // - Member function declarations with the same name and the same
1227 // parameter-type-list as well as member function template
1228 // declarations with the same name, the same parameter-type-list, and
1229 // the same template parameter lists cannot be overloaded if any of
1230 // them, but not all, have a ref-qualifier (8.3.5).
1231 Diag(NewMethod->getLocation(), diag::err_ref_qualifier_overload)
1232 << NewMethod->getRefQualifier() << OldMethod->getRefQualifier();
1233 Diag(OldMethod->getLocation(), diag::note_previous_declaration);
1234 }
1235 return true;
1236 }
1237
1238 // We may not have applied the implicit const for a constexpr member
1239 // function yet (because we haven't yet resolved whether this is a static
1240 // or non-static member function). Add it now, on the assumption that this
1241 // is a redeclaration of OldMethod.
1242 auto OldQuals = OldMethod->getMethodQualifiers();
1243 auto NewQuals = NewMethod->getMethodQualifiers();
1244 if (!getLangOpts().CPlusPlus14 && NewMethod->isConstexpr() &&
1245 !isa<CXXConstructorDecl>(NewMethod))
1246 NewQuals.addConst();
1247 // We do not allow overloading based off of '__restrict'.
1248 OldQuals.removeRestrict();
1249 NewQuals.removeRestrict();
1250 if (OldQuals != NewQuals)
1251 return true;
1252 }
1253
1254 // Though pass_object_size is placed on parameters and takes an argument, we
1255 // consider it to be a function-level modifier for the sake of function
1256 // identity. Either the function has one or more parameters with
1257 // pass_object_size or it doesn't.
1258 if (functionHasPassObjectSizeParams(New) !=
1259 functionHasPassObjectSizeParams(Old))
1260 return true;
1261
1262 // enable_if attributes are an order-sensitive part of the signature.
1263 for (specific_attr_iterator<EnableIfAttr>
1264 NewI = New->specific_attr_begin<EnableIfAttr>(),
1265 NewE = New->specific_attr_end<EnableIfAttr>(),
1266 OldI = Old->specific_attr_begin<EnableIfAttr>(),
1267 OldE = Old->specific_attr_end<EnableIfAttr>();
1268 NewI != NewE || OldI != OldE; ++NewI, ++OldI) {
1269 if (NewI == NewE || OldI == OldE)
1270 return true;
1271 llvm::FoldingSetNodeID NewID, OldID;
1272 NewI->getCond()->Profile(NewID, Context, true);
1273 OldI->getCond()->Profile(OldID, Context, true);
1274 if (NewID != OldID)
1275 return true;
1276 }
1277
1278 if (getLangOpts().CUDA && ConsiderCudaAttrs) {
1279 // Don't allow overloading of destructors. (In theory we could, but it
1280 // would be a giant change to clang.)
1281 if (!isa<CXXDestructorDecl>(New)) {
1282 CUDAFunctionTarget NewTarget = IdentifyCUDATarget(New),
1283 OldTarget = IdentifyCUDATarget(Old);
1284 if (NewTarget != CFT_InvalidTarget) {
1285 assert((OldTarget != CFT_InvalidTarget) &&
1286 "Unexpected invalid target.");
1287
1288 // Allow overloading of functions with same signature and different CUDA
1289 // target attributes.
1290 if (NewTarget != OldTarget)
1291 return true;
1292 }
1293 }
1294 }
1295
1296 if (ConsiderRequiresClauses) {
1297 Expr *NewRC = New->getTrailingRequiresClause(),
1298 *OldRC = Old->getTrailingRequiresClause();
1299 if ((NewRC != nullptr) != (OldRC != nullptr))
1300 // RC are most certainly different - these are overloads.
1301 return true;
1302
1303 if (NewRC) {
1304 llvm::FoldingSetNodeID NewID, OldID;
1305 NewRC->Profile(NewID, Context, /*Canonical=*/true);
1306 OldRC->Profile(OldID, Context, /*Canonical=*/true);
1307 if (NewID != OldID)
1308 // RCs are not equivalent - these are overloads.
1309 return true;
1310 }
1311 }
1312
1313 // The signatures match; this is not an overload.
1314 return false;
1315 }
1316
1317 /// Tries a user-defined conversion from From to ToType.
1318 ///
1319 /// Produces an implicit conversion sequence for when a standard conversion
1320 /// is not an option. See TryImplicitConversion for more information.
1321 static ImplicitConversionSequence
TryUserDefinedConversion(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion,bool AllowObjCConversionOnExplicit)1322 TryUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
1323 bool SuppressUserConversions,
1324 AllowedExplicit AllowExplicit,
1325 bool InOverloadResolution,
1326 bool CStyle,
1327 bool AllowObjCWritebackConversion,
1328 bool AllowObjCConversionOnExplicit) {
1329 ImplicitConversionSequence ICS;
1330
1331 if (SuppressUserConversions) {
1332 // We're not in the case above, so there is no conversion that
1333 // we can perform.
1334 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1335 return ICS;
1336 }
1337
1338 // Attempt user-defined conversion.
1339 OverloadCandidateSet Conversions(From->getExprLoc(),
1340 OverloadCandidateSet::CSK_Normal);
1341 switch (IsUserDefinedConversion(S, From, ToType, ICS.UserDefined,
1342 Conversions, AllowExplicit,
1343 AllowObjCConversionOnExplicit)) {
1344 case OR_Success:
1345 case OR_Deleted:
1346 ICS.setUserDefined();
1347 // C++ [over.ics.user]p4:
1348 // A conversion of an expression of class type to the same class
1349 // type is given Exact Match rank, and a conversion of an
1350 // expression of class type to a base class of that type is
1351 // given Conversion rank, in spite of the fact that a copy
1352 // constructor (i.e., a user-defined conversion function) is
1353 // called for those cases.
1354 if (CXXConstructorDecl *Constructor
1355 = dyn_cast<CXXConstructorDecl>(ICS.UserDefined.ConversionFunction)) {
1356 QualType FromCanon
1357 = S.Context.getCanonicalType(From->getType().getUnqualifiedType());
1358 QualType ToCanon
1359 = S.Context.getCanonicalType(ToType).getUnqualifiedType();
1360 if (Constructor->isCopyConstructor() &&
1361 (FromCanon == ToCanon ||
1362 S.IsDerivedFrom(From->getBeginLoc(), FromCanon, ToCanon))) {
1363 // Turn this into a "standard" conversion sequence, so that it
1364 // gets ranked with standard conversion sequences.
1365 DeclAccessPair Found = ICS.UserDefined.FoundConversionFunction;
1366 ICS.setStandard();
1367 ICS.Standard.setAsIdentityConversion();
1368 ICS.Standard.setFromType(From->getType());
1369 ICS.Standard.setAllToTypes(ToType);
1370 ICS.Standard.CopyConstructor = Constructor;
1371 ICS.Standard.FoundCopyConstructor = Found;
1372 if (ToCanon != FromCanon)
1373 ICS.Standard.Second = ICK_Derived_To_Base;
1374 }
1375 }
1376 break;
1377
1378 case OR_Ambiguous:
1379 ICS.setAmbiguous();
1380 ICS.Ambiguous.setFromType(From->getType());
1381 ICS.Ambiguous.setToType(ToType);
1382 for (OverloadCandidateSet::iterator Cand = Conversions.begin();
1383 Cand != Conversions.end(); ++Cand)
1384 if (Cand->Best)
1385 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
1386 break;
1387
1388 // Fall through.
1389 case OR_No_Viable_Function:
1390 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1391 break;
1392 }
1393
1394 return ICS;
1395 }
1396
1397 /// TryImplicitConversion - Attempt to perform an implicit conversion
1398 /// from the given expression (Expr) to the given type (ToType). This
1399 /// function returns an implicit conversion sequence that can be used
1400 /// to perform the initialization. Given
1401 ///
1402 /// void f(float f);
1403 /// void g(int i) { f(i); }
1404 ///
1405 /// this routine would produce an implicit conversion sequence to
1406 /// describe the initialization of f from i, which will be a standard
1407 /// conversion sequence containing an lvalue-to-rvalue conversion (C++
1408 /// 4.1) followed by a floating-integral conversion (C++ 4.9).
1409 //
1410 /// Note that this routine only determines how the conversion can be
1411 /// performed; it does not actually perform the conversion. As such,
1412 /// it will not produce any diagnostics if no conversion is available,
1413 /// but will instead return an implicit conversion sequence of kind
1414 /// "BadConversion".
1415 ///
1416 /// If @p SuppressUserConversions, then user-defined conversions are
1417 /// not permitted.
1418 /// If @p AllowExplicit, then explicit user-defined conversions are
1419 /// permitted.
1420 ///
1421 /// \param AllowObjCWritebackConversion Whether we allow the Objective-C
1422 /// writeback conversion, which allows __autoreleasing id* parameters to
1423 /// be initialized with __strong id* or __weak id* arguments.
1424 static ImplicitConversionSequence
TryImplicitConversion(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion,bool AllowObjCConversionOnExplicit)1425 TryImplicitConversion(Sema &S, Expr *From, QualType ToType,
1426 bool SuppressUserConversions,
1427 AllowedExplicit AllowExplicit,
1428 bool InOverloadResolution,
1429 bool CStyle,
1430 bool AllowObjCWritebackConversion,
1431 bool AllowObjCConversionOnExplicit) {
1432 ImplicitConversionSequence ICS;
1433 if (IsStandardConversion(S, From, ToType, InOverloadResolution,
1434 ICS.Standard, CStyle, AllowObjCWritebackConversion)){
1435 ICS.setStandard();
1436 return ICS;
1437 }
1438
1439 if (!S.getLangOpts().CPlusPlus) {
1440 ICS.setBad(BadConversionSequence::no_conversion, From, ToType);
1441 return ICS;
1442 }
1443
1444 // C++ [over.ics.user]p4:
1445 // A conversion of an expression of class type to the same class
1446 // type is given Exact Match rank, and a conversion of an
1447 // expression of class type to a base class of that type is
1448 // given Conversion rank, in spite of the fact that a copy/move
1449 // constructor (i.e., a user-defined conversion function) is
1450 // called for those cases.
1451 QualType FromType = From->getType();
1452 if (ToType->getAs<RecordType>() && FromType->getAs<RecordType>() &&
1453 (S.Context.hasSameUnqualifiedType(FromType, ToType) ||
1454 S.IsDerivedFrom(From->getBeginLoc(), FromType, ToType))) {
1455 ICS.setStandard();
1456 ICS.Standard.setAsIdentityConversion();
1457 ICS.Standard.setFromType(FromType);
1458 ICS.Standard.setAllToTypes(ToType);
1459
1460 // We don't actually check at this point whether there is a valid
1461 // copy/move constructor, since overloading just assumes that it
1462 // exists. When we actually perform initialization, we'll find the
1463 // appropriate constructor to copy the returned object, if needed.
1464 ICS.Standard.CopyConstructor = nullptr;
1465
1466 // Determine whether this is considered a derived-to-base conversion.
1467 if (!S.Context.hasSameUnqualifiedType(FromType, ToType))
1468 ICS.Standard.Second = ICK_Derived_To_Base;
1469
1470 return ICS;
1471 }
1472
1473 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
1474 AllowExplicit, InOverloadResolution, CStyle,
1475 AllowObjCWritebackConversion,
1476 AllowObjCConversionOnExplicit);
1477 }
1478
1479 ImplicitConversionSequence
TryImplicitConversion(Expr * From,QualType ToType,bool SuppressUserConversions,AllowedExplicit AllowExplicit,bool InOverloadResolution,bool CStyle,bool AllowObjCWritebackConversion)1480 Sema::TryImplicitConversion(Expr *From, QualType ToType,
1481 bool SuppressUserConversions,
1482 AllowedExplicit AllowExplicit,
1483 bool InOverloadResolution,
1484 bool CStyle,
1485 bool AllowObjCWritebackConversion) {
1486 return ::TryImplicitConversion(*this, From, ToType, SuppressUserConversions,
1487 AllowExplicit, InOverloadResolution, CStyle,
1488 AllowObjCWritebackConversion,
1489 /*AllowObjCConversionOnExplicit=*/false);
1490 }
1491
1492 /// PerformImplicitConversion - Perform an implicit conversion of the
1493 /// expression From to the type ToType. Returns the
1494 /// converted expression. Flavor is the kind of conversion we're
1495 /// performing, used in the error message. If @p AllowExplicit,
1496 /// explicit user-defined conversions are permitted.
PerformImplicitConversion(Expr * From,QualType ToType,AssignmentAction Action,bool AllowExplicit)1497 ExprResult Sema::PerformImplicitConversion(Expr *From, QualType ToType,
1498 AssignmentAction Action,
1499 bool AllowExplicit) {
1500 if (checkPlaceholderForOverload(*this, From))
1501 return ExprError();
1502
1503 // Objective-C ARC: Determine whether we will allow the writeback conversion.
1504 bool AllowObjCWritebackConversion
1505 = getLangOpts().ObjCAutoRefCount &&
1506 (Action == AA_Passing || Action == AA_Sending);
1507 if (getLangOpts().ObjC)
1508 CheckObjCBridgeRelatedConversions(From->getBeginLoc(), ToType,
1509 From->getType(), From);
1510 ImplicitConversionSequence ICS = ::TryImplicitConversion(
1511 *this, From, ToType,
1512 /*SuppressUserConversions=*/false,
1513 AllowExplicit ? AllowedExplicit::All : AllowedExplicit::None,
1514 /*InOverloadResolution=*/false,
1515 /*CStyle=*/false, AllowObjCWritebackConversion,
1516 /*AllowObjCConversionOnExplicit=*/false);
1517 return PerformImplicitConversion(From, ToType, ICS, Action);
1518 }
1519
1520 /// Determine whether the conversion from FromType to ToType is a valid
1521 /// conversion that strips "noexcept" or "noreturn" off the nested function
1522 /// type.
IsFunctionConversion(QualType FromType,QualType ToType,QualType & ResultTy)1523 bool Sema::IsFunctionConversion(QualType FromType, QualType ToType,
1524 QualType &ResultTy) {
1525 if (Context.hasSameUnqualifiedType(FromType, ToType))
1526 return false;
1527
1528 // Permit the conversion F(t __attribute__((noreturn))) -> F(t)
1529 // or F(t noexcept) -> F(t)
1530 // where F adds one of the following at most once:
1531 // - a pointer
1532 // - a member pointer
1533 // - a block pointer
1534 // Changes here need matching changes in FindCompositePointerType.
1535 CanQualType CanTo = Context.getCanonicalType(ToType);
1536 CanQualType CanFrom = Context.getCanonicalType(FromType);
1537 Type::TypeClass TyClass = CanTo->getTypeClass();
1538 if (TyClass != CanFrom->getTypeClass()) return false;
1539 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto) {
1540 if (TyClass == Type::Pointer) {
1541 CanTo = CanTo.castAs<PointerType>()->getPointeeType();
1542 CanFrom = CanFrom.castAs<PointerType>()->getPointeeType();
1543 } else if (TyClass == Type::BlockPointer) {
1544 CanTo = CanTo.castAs<BlockPointerType>()->getPointeeType();
1545 CanFrom = CanFrom.castAs<BlockPointerType>()->getPointeeType();
1546 } else if (TyClass == Type::MemberPointer) {
1547 auto ToMPT = CanTo.castAs<MemberPointerType>();
1548 auto FromMPT = CanFrom.castAs<MemberPointerType>();
1549 // A function pointer conversion cannot change the class of the function.
1550 if (ToMPT->getClass() != FromMPT->getClass())
1551 return false;
1552 CanTo = ToMPT->getPointeeType();
1553 CanFrom = FromMPT->getPointeeType();
1554 } else {
1555 return false;
1556 }
1557
1558 TyClass = CanTo->getTypeClass();
1559 if (TyClass != CanFrom->getTypeClass()) return false;
1560 if (TyClass != Type::FunctionProto && TyClass != Type::FunctionNoProto)
1561 return false;
1562 }
1563
1564 const auto *FromFn = cast<FunctionType>(CanFrom);
1565 FunctionType::ExtInfo FromEInfo = FromFn->getExtInfo();
1566
1567 const auto *ToFn = cast<FunctionType>(CanTo);
1568 FunctionType::ExtInfo ToEInfo = ToFn->getExtInfo();
1569
1570 bool Changed = false;
1571
1572 // Drop 'noreturn' if not present in target type.
1573 if (FromEInfo.getNoReturn() && !ToEInfo.getNoReturn()) {
1574 FromFn = Context.adjustFunctionType(FromFn, FromEInfo.withNoReturn(false));
1575 Changed = true;
1576 }
1577
1578 // Drop 'noexcept' if not present in target type.
1579 if (const auto *FromFPT = dyn_cast<FunctionProtoType>(FromFn)) {
1580 const auto *ToFPT = cast<FunctionProtoType>(ToFn);
1581 if (FromFPT->isNothrow() && !ToFPT->isNothrow()) {
1582 FromFn = cast<FunctionType>(
1583 Context.getFunctionTypeWithExceptionSpec(QualType(FromFPT, 0),
1584 EST_None)
1585 .getTypePtr());
1586 Changed = true;
1587 }
1588
1589 // Convert FromFPT's ExtParameterInfo if necessary. The conversion is valid
1590 // only if the ExtParameterInfo lists of the two function prototypes can be
1591 // merged and the merged list is identical to ToFPT's ExtParameterInfo list.
1592 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
1593 bool CanUseToFPT, CanUseFromFPT;
1594 if (Context.mergeExtParameterInfo(ToFPT, FromFPT, CanUseToFPT,
1595 CanUseFromFPT, NewParamInfos) &&
1596 CanUseToFPT && !CanUseFromFPT) {
1597 FunctionProtoType::ExtProtoInfo ExtInfo = FromFPT->getExtProtoInfo();
1598 ExtInfo.ExtParameterInfos =
1599 NewParamInfos.empty() ? nullptr : NewParamInfos.data();
1600 QualType QT = Context.getFunctionType(FromFPT->getReturnType(),
1601 FromFPT->getParamTypes(), ExtInfo);
1602 FromFn = QT->getAs<FunctionType>();
1603 Changed = true;
1604 }
1605 }
1606
1607 if (!Changed)
1608 return false;
1609
1610 assert(QualType(FromFn, 0).isCanonical());
1611 if (QualType(FromFn, 0) != CanTo) return false;
1612
1613 ResultTy = ToType;
1614 return true;
1615 }
1616
1617 /// Determine whether the conversion from FromType to ToType is a valid
1618 /// vector conversion.
1619 ///
1620 /// \param ICK Will be set to the vector conversion kind, if this is a vector
1621 /// conversion.
IsVectorConversion(Sema & S,QualType FromType,QualType ToType,ImplicitConversionKind & ICK)1622 static bool IsVectorConversion(Sema &S, QualType FromType,
1623 QualType ToType, ImplicitConversionKind &ICK) {
1624 // We need at least one of these types to be a vector type to have a vector
1625 // conversion.
1626 if (!ToType->isVectorType() && !FromType->isVectorType())
1627 return false;
1628
1629 // Identical types require no conversions.
1630 if (S.Context.hasSameUnqualifiedType(FromType, ToType))
1631 return false;
1632
1633 // There are no conversions between extended vector types, only identity.
1634 if (ToType->isExtVectorType()) {
1635 // There are no conversions between extended vector types other than the
1636 // identity conversion.
1637 if (FromType->isExtVectorType())
1638 return false;
1639
1640 // Vector splat from any arithmetic type to a vector.
1641 if (FromType->isArithmeticType()) {
1642 ICK = ICK_Vector_Splat;
1643 return true;
1644 }
1645 }
1646
1647 if (ToType->isSizelessBuiltinType() || FromType->isSizelessBuiltinType())
1648 if (S.Context.areCompatibleSveTypes(FromType, ToType) ||
1649 S.Context.areLaxCompatibleSveTypes(FromType, ToType)) {
1650 ICK = ICK_SVE_Vector_Conversion;
1651 return true;
1652 }
1653
1654 // We can perform the conversion between vector types in the following cases:
1655 // 1)vector types are equivalent AltiVec and GCC vector types
1656 // 2)lax vector conversions are permitted and the vector types are of the
1657 // same size
1658 // 3)the destination type does not have the ARM MVE strict-polymorphism
1659 // attribute, which inhibits lax vector conversion for overload resolution
1660 // only
1661 if (ToType->isVectorType() && FromType->isVectorType()) {
1662 if (S.Context.areCompatibleVectorTypes(FromType, ToType) ||
1663 (S.isLaxVectorConversion(FromType, ToType) &&
1664 !ToType->hasAttr(attr::ArmMveStrictPolymorphism))) {
1665 ICK = ICK_Vector_Conversion;
1666 return true;
1667 }
1668 }
1669
1670 return false;
1671 }
1672
1673 static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
1674 bool InOverloadResolution,
1675 StandardConversionSequence &SCS,
1676 bool CStyle);
1677
1678 /// IsStandardConversion - Determines whether there is a standard
1679 /// conversion sequence (C++ [conv], C++ [over.ics.scs]) from the
1680 /// expression From to the type ToType. Standard conversion sequences
1681 /// only consider non-class types; for conversions that involve class
1682 /// types, use TryImplicitConversion. If a conversion exists, SCS will
1683 /// contain the standard conversion sequence required to perform this
1684 /// conversion and this routine will return true. Otherwise, this
1685 /// routine will return false and the value of SCS is unspecified.
IsStandardConversion(Sema & S,Expr * From,QualType ToType,bool InOverloadResolution,StandardConversionSequence & SCS,bool CStyle,bool AllowObjCWritebackConversion)1686 static bool IsStandardConversion(Sema &S, Expr* From, QualType ToType,
1687 bool InOverloadResolution,
1688 StandardConversionSequence &SCS,
1689 bool CStyle,
1690 bool AllowObjCWritebackConversion) {
1691 QualType FromType = From->getType();
1692
1693 // Standard conversions (C++ [conv])
1694 SCS.setAsIdentityConversion();
1695 SCS.IncompatibleObjC = false;
1696 SCS.setFromType(FromType);
1697 SCS.CopyConstructor = nullptr;
1698
1699 // There are no standard conversions for class types in C++, so
1700 // abort early. When overloading in C, however, we do permit them.
1701 if (S.getLangOpts().CPlusPlus &&
1702 (FromType->isRecordType() || ToType->isRecordType()))
1703 return false;
1704
1705 // The first conversion can be an lvalue-to-rvalue conversion,
1706 // array-to-pointer conversion, or function-to-pointer conversion
1707 // (C++ 4p1).
1708
1709 if (FromType == S.Context.OverloadTy) {
1710 DeclAccessPair AccessPair;
1711 if (FunctionDecl *Fn
1712 = S.ResolveAddressOfOverloadedFunction(From, ToType, false,
1713 AccessPair)) {
1714 // We were able to resolve the address of the overloaded function,
1715 // so we can convert to the type of that function.
1716 FromType = Fn->getType();
1717 SCS.setFromType(FromType);
1718
1719 // we can sometimes resolve &foo<int> regardless of ToType, so check
1720 // if the type matches (identity) or we are converting to bool
1721 if (!S.Context.hasSameUnqualifiedType(
1722 S.ExtractUnqualifiedFunctionType(ToType), FromType)) {
1723 QualType resultTy;
1724 // if the function type matches except for [[noreturn]], it's ok
1725 if (!S.IsFunctionConversion(FromType,
1726 S.ExtractUnqualifiedFunctionType(ToType), resultTy))
1727 // otherwise, only a boolean conversion is standard
1728 if (!ToType->isBooleanType())
1729 return false;
1730 }
1731
1732 // Check if the "from" expression is taking the address of an overloaded
1733 // function and recompute the FromType accordingly. Take advantage of the
1734 // fact that non-static member functions *must* have such an address-of
1735 // expression.
1736 CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn);
1737 if (Method && !Method->isStatic()) {
1738 assert(isa<UnaryOperator>(From->IgnoreParens()) &&
1739 "Non-unary operator on non-static member address");
1740 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode()
1741 == UO_AddrOf &&
1742 "Non-address-of operator on non-static member address");
1743 const Type *ClassType
1744 = S.Context.getTypeDeclType(Method->getParent()).getTypePtr();
1745 FromType = S.Context.getMemberPointerType(FromType, ClassType);
1746 } else if (isa<UnaryOperator>(From->IgnoreParens())) {
1747 assert(cast<UnaryOperator>(From->IgnoreParens())->getOpcode() ==
1748 UO_AddrOf &&
1749 "Non-address-of operator for overloaded function expression");
1750 FromType = S.Context.getPointerType(FromType);
1751 }
1752
1753 // Check that we've computed the proper type after overload resolution.
1754 // FIXME: FixOverloadedFunctionReference has side-effects; we shouldn't
1755 // be calling it from within an NDEBUG block.
1756 assert(S.Context.hasSameType(
1757 FromType,
1758 S.FixOverloadedFunctionReference(From, AccessPair, Fn)->getType()));
1759 } else {
1760 return false;
1761 }
1762 }
1763 // Lvalue-to-rvalue conversion (C++11 4.1):
1764 // A glvalue (3.10) of a non-function, non-array type T can
1765 // be converted to a prvalue.
1766 bool argIsLValue = From->isGLValue();
1767 if (argIsLValue &&
1768 !FromType->isFunctionType() && !FromType->isArrayType() &&
1769 S.Context.getCanonicalType(FromType) != S.Context.OverloadTy) {
1770 SCS.First = ICK_Lvalue_To_Rvalue;
1771
1772 // C11 6.3.2.1p2:
1773 // ... if the lvalue has atomic type, the value has the non-atomic version
1774 // of the type of the lvalue ...
1775 if (const AtomicType *Atomic = FromType->getAs<AtomicType>())
1776 FromType = Atomic->getValueType();
1777
1778 // If T is a non-class type, the type of the rvalue is the
1779 // cv-unqualified version of T. Otherwise, the type of the rvalue
1780 // is T (C++ 4.1p1). C++ can't get here with class types; in C, we
1781 // just strip the qualifiers because they don't matter.
1782 FromType = FromType.getUnqualifiedType();
1783 } else if (FromType->isArrayType()) {
1784 // Array-to-pointer conversion (C++ 4.2)
1785 SCS.First = ICK_Array_To_Pointer;
1786
1787 // An lvalue or rvalue of type "array of N T" or "array of unknown
1788 // bound of T" can be converted to an rvalue of type "pointer to
1789 // T" (C++ 4.2p1).
1790 FromType = S.Context.getArrayDecayedType(FromType);
1791
1792 if (S.IsStringLiteralToNonConstPointerConversion(From, ToType)) {
1793 // This conversion is deprecated in C++03 (D.4)
1794 SCS.DeprecatedStringLiteralToCharPtr = true;
1795
1796 // For the purpose of ranking in overload resolution
1797 // (13.3.3.1.1), this conversion is considered an
1798 // array-to-pointer conversion followed by a qualification
1799 // conversion (4.4). (C++ 4.2p2)
1800 SCS.Second = ICK_Identity;
1801 SCS.Third = ICK_Qualification;
1802 SCS.QualificationIncludesObjCLifetime = false;
1803 SCS.setAllToTypes(FromType);
1804 return true;
1805 }
1806 } else if (FromType->isFunctionType() && argIsLValue) {
1807 // Function-to-pointer conversion (C++ 4.3).
1808 SCS.First = ICK_Function_To_Pointer;
1809
1810 if (auto *DRE = dyn_cast<DeclRefExpr>(From->IgnoreParenCasts()))
1811 if (auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl()))
1812 if (!S.checkAddressOfFunctionIsAvailable(FD))
1813 return false;
1814
1815 // An lvalue of function type T can be converted to an rvalue of
1816 // type "pointer to T." The result is a pointer to the
1817 // function. (C++ 4.3p1).
1818 FromType = S.Context.getPointerType(FromType);
1819 } else {
1820 // We don't require any conversions for the first step.
1821 SCS.First = ICK_Identity;
1822 }
1823 SCS.setToType(0, FromType);
1824
1825 // The second conversion can be an integral promotion, floating
1826 // point promotion, integral conversion, floating point conversion,
1827 // floating-integral conversion, pointer conversion,
1828 // pointer-to-member conversion, or boolean conversion (C++ 4p1).
1829 // For overloading in C, this can also be a "compatible-type"
1830 // conversion.
1831 bool IncompatibleObjC = false;
1832 ImplicitConversionKind SecondICK = ICK_Identity;
1833 if (S.Context.hasSameUnqualifiedType(FromType, ToType)) {
1834 // The unqualified versions of the types are the same: there's no
1835 // conversion to do.
1836 SCS.Second = ICK_Identity;
1837 } else if (S.IsIntegralPromotion(From, FromType, ToType)) {
1838 // Integral promotion (C++ 4.5).
1839 SCS.Second = ICK_Integral_Promotion;
1840 FromType = ToType.getUnqualifiedType();
1841 } else if (S.IsFloatingPointPromotion(FromType, ToType)) {
1842 // Floating point promotion (C++ 4.6).
1843 SCS.Second = ICK_Floating_Promotion;
1844 FromType = ToType.getUnqualifiedType();
1845 } else if (S.IsComplexPromotion(FromType, ToType)) {
1846 // Complex promotion (Clang extension)
1847 SCS.Second = ICK_Complex_Promotion;
1848 FromType = ToType.getUnqualifiedType();
1849 } else if (ToType->isBooleanType() &&
1850 (FromType->isArithmeticType() ||
1851 FromType->isAnyPointerType() ||
1852 FromType->isBlockPointerType() ||
1853 FromType->isMemberPointerType())) {
1854 // Boolean conversions (C++ 4.12).
1855 SCS.Second = ICK_Boolean_Conversion;
1856 FromType = S.Context.BoolTy;
1857 } else if (FromType->isIntegralOrUnscopedEnumerationType() &&
1858 ToType->isIntegralType(S.Context)) {
1859 // Integral conversions (C++ 4.7).
1860 SCS.Second = ICK_Integral_Conversion;
1861 FromType = ToType.getUnqualifiedType();
1862 } else if (FromType->isAnyComplexType() && ToType->isAnyComplexType()) {
1863 // Complex conversions (C99 6.3.1.6)
1864 SCS.Second = ICK_Complex_Conversion;
1865 FromType = ToType.getUnqualifiedType();
1866 } else if ((FromType->isAnyComplexType() && ToType->isArithmeticType()) ||
1867 (ToType->isAnyComplexType() && FromType->isArithmeticType())) {
1868 // Complex-real conversions (C99 6.3.1.7)
1869 SCS.Second = ICK_Complex_Real;
1870 FromType = ToType.getUnqualifiedType();
1871 } else if (FromType->isRealFloatingType() && ToType->isRealFloatingType()) {
1872 // FIXME: disable conversions between long double, __ibm128 and __float128
1873 // if their representation is different until there is back end support
1874 // We of course allow this conversion if long double is really double.
1875
1876 // Conversions between bfloat and other floats are not permitted.
1877 if (FromType == S.Context.BFloat16Ty || ToType == S.Context.BFloat16Ty)
1878 return false;
1879
1880 // Conversions between IEEE-quad and IBM-extended semantics are not
1881 // permitted.
1882 const llvm::fltSemantics &FromSem =
1883 S.Context.getFloatTypeSemantics(FromType);
1884 const llvm::fltSemantics &ToSem = S.Context.getFloatTypeSemantics(ToType);
1885 if ((&FromSem == &llvm::APFloat::PPCDoubleDouble() &&
1886 &ToSem == &llvm::APFloat::IEEEquad()) ||
1887 (&FromSem == &llvm::APFloat::IEEEquad() &&
1888 &ToSem == &llvm::APFloat::PPCDoubleDouble()))
1889 return false;
1890
1891 // Floating point conversions (C++ 4.8).
1892 SCS.Second = ICK_Floating_Conversion;
1893 FromType = ToType.getUnqualifiedType();
1894 } else if ((FromType->isRealFloatingType() &&
1895 ToType->isIntegralType(S.Context)) ||
1896 (FromType->isIntegralOrUnscopedEnumerationType() &&
1897 ToType->isRealFloatingType())) {
1898 // Conversions between bfloat and int are not permitted.
1899 if (FromType->isBFloat16Type() || ToType->isBFloat16Type())
1900 return false;
1901
1902 // Floating-integral conversions (C++ 4.9).
1903 SCS.Second = ICK_Floating_Integral;
1904 FromType = ToType.getUnqualifiedType();
1905 } else if (S.IsBlockPointerConversion(FromType, ToType, FromType)) {
1906 SCS.Second = ICK_Block_Pointer_Conversion;
1907 } else if (AllowObjCWritebackConversion &&
1908 S.isObjCWritebackConversion(FromType, ToType, FromType)) {
1909 SCS.Second = ICK_Writeback_Conversion;
1910 } else if (S.IsPointerConversion(From, FromType, ToType, InOverloadResolution,
1911 FromType, IncompatibleObjC)) {
1912 // Pointer conversions (C++ 4.10).
1913 SCS.Second = ICK_Pointer_Conversion;
1914 SCS.IncompatibleObjC = IncompatibleObjC;
1915 FromType = FromType.getUnqualifiedType();
1916 } else if (S.IsMemberPointerConversion(From, FromType, ToType,
1917 InOverloadResolution, FromType)) {
1918 // Pointer to member conversions (4.11).
1919 SCS.Second = ICK_Pointer_Member;
1920 } else if (IsVectorConversion(S, FromType, ToType, SecondICK)) {
1921 SCS.Second = SecondICK;
1922 FromType = ToType.getUnqualifiedType();
1923 } else if (!S.getLangOpts().CPlusPlus &&
1924 S.Context.typesAreCompatible(ToType, FromType)) {
1925 // Compatible conversions (Clang extension for C function overloading)
1926 SCS.Second = ICK_Compatible_Conversion;
1927 FromType = ToType.getUnqualifiedType();
1928 } else if (IsTransparentUnionStandardConversion(S, From, ToType,
1929 InOverloadResolution,
1930 SCS, CStyle)) {
1931 SCS.Second = ICK_TransparentUnionConversion;
1932 FromType = ToType;
1933 } else if (tryAtomicConversion(S, From, ToType, InOverloadResolution, SCS,
1934 CStyle)) {
1935 // tryAtomicConversion has updated the standard conversion sequence
1936 // appropriately.
1937 return true;
1938 } else if (ToType->isEventT() &&
1939 From->isIntegerConstantExpr(S.getASTContext()) &&
1940 From->EvaluateKnownConstInt(S.getASTContext()) == 0) {
1941 SCS.Second = ICK_Zero_Event_Conversion;
1942 FromType = ToType;
1943 } else if (ToType->isQueueT() &&
1944 From->isIntegerConstantExpr(S.getASTContext()) &&
1945 (From->EvaluateKnownConstInt(S.getASTContext()) == 0)) {
1946 SCS.Second = ICK_Zero_Queue_Conversion;
1947 FromType = ToType;
1948 } else if (ToType->isSamplerT() &&
1949 From->isIntegerConstantExpr(S.getASTContext())) {
1950 SCS.Second = ICK_Compatible_Conversion;
1951 FromType = ToType;
1952 } else {
1953 // No second conversion required.
1954 SCS.Second = ICK_Identity;
1955 }
1956 SCS.setToType(1, FromType);
1957
1958 // The third conversion can be a function pointer conversion or a
1959 // qualification conversion (C++ [conv.fctptr], [conv.qual]).
1960 bool ObjCLifetimeConversion;
1961 if (S.IsFunctionConversion(FromType, ToType, FromType)) {
1962 // Function pointer conversions (removing 'noexcept') including removal of
1963 // 'noreturn' (Clang extension).
1964 SCS.Third = ICK_Function_Conversion;
1965 } else if (S.IsQualificationConversion(FromType, ToType, CStyle,
1966 ObjCLifetimeConversion)) {
1967 SCS.Third = ICK_Qualification;
1968 SCS.QualificationIncludesObjCLifetime = ObjCLifetimeConversion;
1969 FromType = ToType;
1970 } else {
1971 // No conversion required
1972 SCS.Third = ICK_Identity;
1973 }
1974
1975 // C++ [over.best.ics]p6:
1976 // [...] Any difference in top-level cv-qualification is
1977 // subsumed by the initialization itself and does not constitute
1978 // a conversion. [...]
1979 QualType CanonFrom = S.Context.getCanonicalType(FromType);
1980 QualType CanonTo = S.Context.getCanonicalType(ToType);
1981 if (CanonFrom.getLocalUnqualifiedType()
1982 == CanonTo.getLocalUnqualifiedType() &&
1983 CanonFrom.getLocalQualifiers() != CanonTo.getLocalQualifiers()) {
1984 FromType = ToType;
1985 CanonFrom = CanonTo;
1986 }
1987
1988 SCS.setToType(2, FromType);
1989
1990 if (CanonFrom == CanonTo)
1991 return true;
1992
1993 // If we have not converted the argument type to the parameter type,
1994 // this is a bad conversion sequence, unless we're resolving an overload in C.
1995 if (S.getLangOpts().CPlusPlus || !InOverloadResolution)
1996 return false;
1997
1998 ExprResult ER = ExprResult{From};
1999 Sema::AssignConvertType Conv =
2000 S.CheckSingleAssignmentConstraints(ToType, ER,
2001 /*Diagnose=*/false,
2002 /*DiagnoseCFAudited=*/false,
2003 /*ConvertRHS=*/false);
2004 ImplicitConversionKind SecondConv;
2005 switch (Conv) {
2006 case Sema::Compatible:
2007 SecondConv = ICK_C_Only_Conversion;
2008 break;
2009 // For our purposes, discarding qualifiers is just as bad as using an
2010 // incompatible pointer. Note that an IncompatiblePointer conversion can drop
2011 // qualifiers, as well.
2012 case Sema::CompatiblePointerDiscardsQualifiers:
2013 case Sema::IncompatiblePointer:
2014 case Sema::IncompatiblePointerSign:
2015 SecondConv = ICK_Incompatible_Pointer_Conversion;
2016 break;
2017 default:
2018 return false;
2019 }
2020
2021 // First can only be an lvalue conversion, so we pretend that this was the
2022 // second conversion. First should already be valid from earlier in the
2023 // function.
2024 SCS.Second = SecondConv;
2025 SCS.setToType(1, ToType);
2026
2027 // Third is Identity, because Second should rank us worse than any other
2028 // conversion. This could also be ICK_Qualification, but it's simpler to just
2029 // lump everything in with the second conversion, and we don't gain anything
2030 // from making this ICK_Qualification.
2031 SCS.Third = ICK_Identity;
2032 SCS.setToType(2, ToType);
2033 return true;
2034 }
2035
2036 static bool
IsTransparentUnionStandardConversion(Sema & S,Expr * From,QualType & ToType,bool InOverloadResolution,StandardConversionSequence & SCS,bool CStyle)2037 IsTransparentUnionStandardConversion(Sema &S, Expr* From,
2038 QualType &ToType,
2039 bool InOverloadResolution,
2040 StandardConversionSequence &SCS,
2041 bool CStyle) {
2042
2043 const RecordType *UT = ToType->getAsUnionType();
2044 if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
2045 return false;
2046 // The field to initialize within the transparent union.
2047 RecordDecl *UD = UT->getDecl();
2048 // It's compatible if the expression matches any of the fields.
2049 for (const auto *it : UD->fields()) {
2050 if (IsStandardConversion(S, From, it->getType(), InOverloadResolution, SCS,
2051 CStyle, /*AllowObjCWritebackConversion=*/false)) {
2052 ToType = it->getType();
2053 return true;
2054 }
2055 }
2056 return false;
2057 }
2058
2059 /// IsIntegralPromotion - Determines whether the conversion from the
2060 /// expression From (whose potentially-adjusted type is FromType) to
2061 /// ToType is an integral promotion (C++ 4.5). If so, returns true and
2062 /// sets PromotedType to the promoted type.
IsIntegralPromotion(Expr * From,QualType FromType,QualType ToType)2063 bool Sema::IsIntegralPromotion(Expr *From, QualType FromType, QualType ToType) {
2064 const BuiltinType *To = ToType->getAs<BuiltinType>();
2065 // All integers are built-in.
2066 if (!To) {
2067 return false;
2068 }
2069
2070 // An rvalue of type char, signed char, unsigned char, short int, or
2071 // unsigned short int can be converted to an rvalue of type int if
2072 // int can represent all the values of the source type; otherwise,
2073 // the source rvalue can be converted to an rvalue of type unsigned
2074 // int (C++ 4.5p1).
2075 if (FromType->isPromotableIntegerType() && !FromType->isBooleanType() &&
2076 !FromType->isEnumeralType()) {
2077 if (// We can promote any signed, promotable integer type to an int
2078 (FromType->isSignedIntegerType() ||
2079 // We can promote any unsigned integer type whose size is
2080 // less than int to an int.
2081 Context.getTypeSize(FromType) < Context.getTypeSize(ToType))) {
2082 return To->getKind() == BuiltinType::Int;
2083 }
2084
2085 return To->getKind() == BuiltinType::UInt;
2086 }
2087
2088 // C++11 [conv.prom]p3:
2089 // A prvalue of an unscoped enumeration type whose underlying type is not
2090 // fixed (7.2) can be converted to an rvalue a prvalue of the first of the
2091 // following types that can represent all the values of the enumeration
2092 // (i.e., the values in the range bmin to bmax as described in 7.2): int,
2093 // unsigned int, long int, unsigned long int, long long int, or unsigned
2094 // long long int. If none of the types in that list can represent all the
2095 // values of the enumeration, an rvalue a prvalue of an unscoped enumeration
2096 // type can be converted to an rvalue a prvalue of the extended integer type
2097 // with lowest integer conversion rank (4.13) greater than the rank of long
2098 // long in which all the values of the enumeration can be represented. If
2099 // there are two such extended types, the signed one is chosen.
2100 // C++11 [conv.prom]p4:
2101 // A prvalue of an unscoped enumeration type whose underlying type is fixed
2102 // can be converted to a prvalue of its underlying type. Moreover, if
2103 // integral promotion can be applied to its underlying type, a prvalue of an
2104 // unscoped enumeration type whose underlying type is fixed can also be
2105 // converted to a prvalue of the promoted underlying type.
2106 if (const EnumType *FromEnumType = FromType->getAs<EnumType>()) {
2107 // C++0x 7.2p9: Note that this implicit enum to int conversion is not
2108 // provided for a scoped enumeration.
2109 if (FromEnumType->getDecl()->isScoped())
2110 return false;
2111
2112 // We can perform an integral promotion to the underlying type of the enum,
2113 // even if that's not the promoted type. Note that the check for promoting
2114 // the underlying type is based on the type alone, and does not consider
2115 // the bitfield-ness of the actual source expression.
2116 if (FromEnumType->getDecl()->isFixed()) {
2117 QualType Underlying = FromEnumType->getDecl()->getIntegerType();
2118 return Context.hasSameUnqualifiedType(Underlying, ToType) ||
2119 IsIntegralPromotion(nullptr, Underlying, ToType);
2120 }
2121
2122 // We have already pre-calculated the promotion type, so this is trivial.
2123 if (ToType->isIntegerType() &&
2124 isCompleteType(From->getBeginLoc(), FromType))
2125 return Context.hasSameUnqualifiedType(
2126 ToType, FromEnumType->getDecl()->getPromotionType());
2127
2128 // C++ [conv.prom]p5:
2129 // If the bit-field has an enumerated type, it is treated as any other
2130 // value of that type for promotion purposes.
2131 //
2132 // ... so do not fall through into the bit-field checks below in C++.
2133 if (getLangOpts().CPlusPlus)
2134 return false;
2135 }
2136
2137 // C++0x [conv.prom]p2:
2138 // A prvalue of type char16_t, char32_t, or wchar_t (3.9.1) can be converted
2139 // to an rvalue a prvalue of the first of the following types that can
2140 // represent all the values of its underlying type: int, unsigned int,
2141 // long int, unsigned long int, long long int, or unsigned long long int.
2142 // If none of the types in that list can represent all the values of its
2143 // underlying type, an rvalue a prvalue of type char16_t, char32_t,
2144 // or wchar_t can be converted to an rvalue a prvalue of its underlying
2145 // type.
2146 if (FromType->isAnyCharacterType() && !FromType->isCharType() &&
2147 ToType->isIntegerType()) {
2148 // Determine whether the type we're converting from is signed or
2149 // unsigned.
2150 bool FromIsSigned = FromType->isSignedIntegerType();
2151 uint64_t FromSize = Context.getTypeSize(FromType);
2152
2153 // The types we'll try to promote to, in the appropriate
2154 // order. Try each of these types.
2155 QualType PromoteTypes[6] = {
2156 Context.IntTy, Context.UnsignedIntTy,
2157 Context.LongTy, Context.UnsignedLongTy ,
2158 Context.LongLongTy, Context.UnsignedLongLongTy
2159 };
2160 for (int Idx = 0; Idx < 6; ++Idx) {
2161 uint64_t ToSize = Context.getTypeSize(PromoteTypes[Idx]);
2162 if (FromSize < ToSize ||
2163 (FromSize == ToSize &&
2164 FromIsSigned == PromoteTypes[Idx]->isSignedIntegerType())) {
2165 // We found the type that we can promote to. If this is the
2166 // type we wanted, we have a promotion. Otherwise, no
2167 // promotion.
2168 return Context.hasSameUnqualifiedType(ToType, PromoteTypes[Idx]);
2169 }
2170 }
2171 }
2172
2173 // An rvalue for an integral bit-field (9.6) can be converted to an
2174 // rvalue of type int if int can represent all the values of the
2175 // bit-field; otherwise, it can be converted to unsigned int if
2176 // unsigned int can represent all the values of the bit-field. If
2177 // the bit-field is larger yet, no integral promotion applies to
2178 // it. If the bit-field has an enumerated type, it is treated as any
2179 // other value of that type for promotion purposes (C++ 4.5p3).
2180 // FIXME: We should delay checking of bit-fields until we actually perform the
2181 // conversion.
2182 //
2183 // FIXME: In C, only bit-fields of types _Bool, int, or unsigned int may be
2184 // promoted, per C11 6.3.1.1/2. We promote all bit-fields (including enum
2185 // bit-fields and those whose underlying type is larger than int) for GCC
2186 // compatibility.
2187 if (From) {
2188 if (FieldDecl *MemberDecl = From->getSourceBitField()) {
2189 Optional<llvm::APSInt> BitWidth;
2190 if (FromType->isIntegralType(Context) &&
2191 (BitWidth =
2192 MemberDecl->getBitWidth()->getIntegerConstantExpr(Context))) {
2193 llvm::APSInt ToSize(BitWidth->getBitWidth(), BitWidth->isUnsigned());
2194 ToSize = Context.getTypeSize(ToType);
2195
2196 // Are we promoting to an int from a bitfield that fits in an int?
2197 if (*BitWidth < ToSize ||
2198 (FromType->isSignedIntegerType() && *BitWidth <= ToSize)) {
2199 return To->getKind() == BuiltinType::Int;
2200 }
2201
2202 // Are we promoting to an unsigned int from an unsigned bitfield
2203 // that fits into an unsigned int?
2204 if (FromType->isUnsignedIntegerType() && *BitWidth <= ToSize) {
2205 return To->getKind() == BuiltinType::UInt;
2206 }
2207
2208 return false;
2209 }
2210 }
2211 }
2212
2213 // An rvalue of type bool can be converted to an rvalue of type int,
2214 // with false becoming zero and true becoming one (C++ 4.5p4).
2215 if (FromType->isBooleanType() && To->getKind() == BuiltinType::Int) {
2216 return true;
2217 }
2218
2219 return false;
2220 }
2221
2222 /// IsFloatingPointPromotion - Determines whether the conversion from
2223 /// FromType to ToType is a floating point promotion (C++ 4.6). If so,
2224 /// returns true and sets PromotedType to the promoted type.
IsFloatingPointPromotion(QualType FromType,QualType ToType)2225 bool Sema::IsFloatingPointPromotion(QualType FromType, QualType ToType) {
2226 if (const BuiltinType *FromBuiltin = FromType->getAs<BuiltinType>())
2227 if (const BuiltinType *ToBuiltin = ToType->getAs<BuiltinType>()) {
2228 /// An rvalue of type float can be converted to an rvalue of type
2229 /// double. (C++ 4.6p1).
2230 if (FromBuiltin->getKind() == BuiltinType::Float &&
2231 ToBuiltin->getKind() == BuiltinType::Double)
2232 return true;
2233
2234 // C99 6.3.1.5p1:
2235 // When a float is promoted to double or long double, or a
2236 // double is promoted to long double [...].
2237 if (!getLangOpts().CPlusPlus &&
2238 (FromBuiltin->getKind() == BuiltinType::Float ||
2239 FromBuiltin->getKind() == BuiltinType::Double) &&
2240 (ToBuiltin->getKind() == BuiltinType::LongDouble ||
2241 ToBuiltin->getKind() == BuiltinType::Float128 ||
2242 ToBuiltin->getKind() == BuiltinType::Ibm128))
2243 return true;
2244
2245 // Half can be promoted to float.
2246 if (!getLangOpts().NativeHalfType &&
2247 FromBuiltin->getKind() == BuiltinType::Half &&
2248 ToBuiltin->getKind() == BuiltinType::Float)
2249 return true;
2250 }
2251
2252 return false;
2253 }
2254
2255 /// Determine if a conversion is a complex promotion.
2256 ///
2257 /// A complex promotion is defined as a complex -> complex conversion
2258 /// where the conversion between the underlying real types is a
2259 /// floating-point or integral promotion.
IsComplexPromotion(QualType FromType,QualType ToType)2260 bool Sema::IsComplexPromotion(QualType FromType, QualType ToType) {
2261 const ComplexType *FromComplex = FromType->getAs<ComplexType>();
2262 if (!FromComplex)
2263 return false;
2264
2265 const ComplexType *ToComplex = ToType->getAs<ComplexType>();
2266 if (!ToComplex)
2267 return false;
2268
2269 return IsFloatingPointPromotion(FromComplex->getElementType(),
2270 ToComplex->getElementType()) ||
2271 IsIntegralPromotion(nullptr, FromComplex->getElementType(),
2272 ToComplex->getElementType());
2273 }
2274
2275 /// BuildSimilarlyQualifiedPointerType - In a pointer conversion from
2276 /// the pointer type FromPtr to a pointer to type ToPointee, with the
2277 /// same type qualifiers as FromPtr has on its pointee type. ToType,
2278 /// if non-empty, will be a pointer to ToType that may or may not have
2279 /// the right set of qualifiers on its pointee.
2280 ///
2281 static QualType
BuildSimilarlyQualifiedPointerType(const Type * FromPtr,QualType ToPointee,QualType ToType,ASTContext & Context,bool StripObjCLifetime=false)2282 BuildSimilarlyQualifiedPointerType(const Type *FromPtr,
2283 QualType ToPointee, QualType ToType,
2284 ASTContext &Context,
2285 bool StripObjCLifetime = false) {
2286 assert((FromPtr->getTypeClass() == Type::Pointer ||
2287 FromPtr->getTypeClass() == Type::ObjCObjectPointer) &&
2288 "Invalid similarly-qualified pointer type");
2289
2290 /// Conversions to 'id' subsume cv-qualifier conversions.
2291 if (ToType->isObjCIdType() || ToType->isObjCQualifiedIdType())
2292 return ToType.getUnqualifiedType();
2293
2294 QualType CanonFromPointee
2295 = Context.getCanonicalType(FromPtr->getPointeeType());
2296 QualType CanonToPointee = Context.getCanonicalType(ToPointee);
2297 Qualifiers Quals = CanonFromPointee.getQualifiers();
2298
2299 if (StripObjCLifetime)
2300 Quals.removeObjCLifetime();
2301
2302 // Exact qualifier match -> return the pointer type we're converting to.
2303 if (CanonToPointee.getLocalQualifiers() == Quals) {
2304 // ToType is exactly what we need. Return it.
2305 if (!ToType.isNull())
2306 return ToType.getUnqualifiedType();
2307
2308 // Build a pointer to ToPointee. It has the right qualifiers
2309 // already.
2310 if (isa<ObjCObjectPointerType>(ToType))
2311 return Context.getObjCObjectPointerType(ToPointee);
2312 return Context.getPointerType(ToPointee);
2313 }
2314
2315 // Just build a canonical type that has the right qualifiers.
2316 QualType QualifiedCanonToPointee
2317 = Context.getQualifiedType(CanonToPointee.getLocalUnqualifiedType(), Quals);
2318
2319 if (isa<ObjCObjectPointerType>(ToType))
2320 return Context.getObjCObjectPointerType(QualifiedCanonToPointee);
2321 return Context.getPointerType(QualifiedCanonToPointee);
2322 }
2323
isNullPointerConstantForConversion(Expr * Expr,bool InOverloadResolution,ASTContext & Context)2324 static bool isNullPointerConstantForConversion(Expr *Expr,
2325 bool InOverloadResolution,
2326 ASTContext &Context) {
2327 // Handle value-dependent integral null pointer constants correctly.
2328 // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#903
2329 if (Expr->isValueDependent() && !Expr->isTypeDependent() &&
2330 Expr->getType()->isIntegerType() && !Expr->getType()->isEnumeralType())
2331 return !InOverloadResolution;
2332
2333 return Expr->isNullPointerConstant(Context,
2334 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
2335 : Expr::NPC_ValueDependentIsNull);
2336 }
2337
2338 /// IsPointerConversion - Determines whether the conversion of the
2339 /// expression From, which has the (possibly adjusted) type FromType,
2340 /// can be converted to the type ToType via a pointer conversion (C++
2341 /// 4.10). If so, returns true and places the converted type (that
2342 /// might differ from ToType in its cv-qualifiers at some level) into
2343 /// ConvertedType.
2344 ///
2345 /// This routine also supports conversions to and from block pointers
2346 /// and conversions with Objective-C's 'id', 'id<protocols...>', and
2347 /// pointers to interfaces. FIXME: Once we've determined the
2348 /// appropriate overloading rules for Objective-C, we may want to
2349 /// split the Objective-C checks into a different routine; however,
2350 /// GCC seems to consider all of these conversions to be pointer
2351 /// conversions, so for now they live here. IncompatibleObjC will be
2352 /// set if the conversion is an allowed Objective-C conversion that
2353 /// should result in a warning.
IsPointerConversion(Expr * From,QualType FromType,QualType ToType,bool InOverloadResolution,QualType & ConvertedType,bool & IncompatibleObjC)2354 bool Sema::IsPointerConversion(Expr *From, QualType FromType, QualType ToType,
2355 bool InOverloadResolution,
2356 QualType& ConvertedType,
2357 bool &IncompatibleObjC) {
2358 IncompatibleObjC = false;
2359 if (isObjCPointerConversion(FromType, ToType, ConvertedType,
2360 IncompatibleObjC))
2361 return true;
2362
2363 // Conversion from a null pointer constant to any Objective-C pointer type.
2364 if (ToType->isObjCObjectPointerType() &&
2365 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2366 ConvertedType = ToType;
2367 return true;
2368 }
2369
2370 // Blocks: Block pointers can be converted to void*.
2371 if (FromType->isBlockPointerType() && ToType->isPointerType() &&
2372 ToType->castAs<PointerType>()->getPointeeType()->isVoidType()) {
2373 ConvertedType = ToType;
2374 return true;
2375 }
2376 // Blocks: A null pointer constant can be converted to a block
2377 // pointer type.
2378 if (ToType->isBlockPointerType() &&
2379 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2380 ConvertedType = ToType;
2381 return true;
2382 }
2383
2384 // If the left-hand-side is nullptr_t, the right side can be a null
2385 // pointer constant.
2386 if (ToType->isNullPtrType() &&
2387 isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2388 ConvertedType = ToType;
2389 return true;
2390 }
2391
2392 const PointerType* ToTypePtr = ToType->getAs<PointerType>();
2393 if (!ToTypePtr)
2394 return false;
2395
2396 // A null pointer constant can be converted to a pointer type (C++ 4.10p1).
2397 if (isNullPointerConstantForConversion(From, InOverloadResolution, Context)) {
2398 ConvertedType = ToType;
2399 return true;
2400 }
2401
2402 // Beyond this point, both types need to be pointers
2403 // , including objective-c pointers.
2404 QualType ToPointeeType = ToTypePtr->getPointeeType();
2405 if (FromType->isObjCObjectPointerType() && ToPointeeType->isVoidType() &&
2406 !getLangOpts().ObjCAutoRefCount) {
2407 ConvertedType = BuildSimilarlyQualifiedPointerType(
2408 FromType->getAs<ObjCObjectPointerType>(),
2409 ToPointeeType,
2410 ToType, Context);
2411 return true;
2412 }
2413 const PointerType *FromTypePtr = FromType->getAs<PointerType>();
2414 if (!FromTypePtr)
2415 return false;
2416
2417 QualType FromPointeeType = FromTypePtr->getPointeeType();
2418
2419 // If the unqualified pointee types are the same, this can't be a
2420 // pointer conversion, so don't do all of the work below.
2421 if (Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType))
2422 return false;
2423
2424 // An rvalue of type "pointer to cv T," where T is an object type,
2425 // can be converted to an rvalue of type "pointer to cv void" (C++
2426 // 4.10p2).
2427 if (FromPointeeType->isIncompleteOrObjectType() &&
2428 ToPointeeType->isVoidType()) {
2429 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2430 ToPointeeType,
2431 ToType, Context,
2432 /*StripObjCLifetime=*/true);
2433 return true;
2434 }
2435
2436 // MSVC allows implicit function to void* type conversion.
2437 if (getLangOpts().MSVCCompat && FromPointeeType->isFunctionType() &&
2438 ToPointeeType->isVoidType()) {
2439 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2440 ToPointeeType,
2441 ToType, Context);
2442 return true;
2443 }
2444
2445 // When we're overloading in C, we allow a special kind of pointer
2446 // conversion for compatible-but-not-identical pointee types.
2447 if (!getLangOpts().CPlusPlus &&
2448 Context.typesAreCompatible(FromPointeeType, ToPointeeType)) {
2449 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2450 ToPointeeType,
2451 ToType, Context);
2452 return true;
2453 }
2454
2455 // C++ [conv.ptr]p3:
2456 //
2457 // An rvalue of type "pointer to cv D," where D is a class type,
2458 // can be converted to an rvalue of type "pointer to cv B," where
2459 // B is a base class (clause 10) of D. If B is an inaccessible
2460 // (clause 11) or ambiguous (10.2) base class of D, a program that
2461 // necessitates this conversion is ill-formed. The result of the
2462 // conversion is a pointer to the base class sub-object of the
2463 // derived class object. The null pointer value is converted to
2464 // the null pointer value of the destination type.
2465 //
2466 // Note that we do not check for ambiguity or inaccessibility
2467 // here. That is handled by CheckPointerConversion.
2468 if (getLangOpts().CPlusPlus && FromPointeeType->isRecordType() &&
2469 ToPointeeType->isRecordType() &&
2470 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType) &&
2471 IsDerivedFrom(From->getBeginLoc(), FromPointeeType, ToPointeeType)) {
2472 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2473 ToPointeeType,
2474 ToType, Context);
2475 return true;
2476 }
2477
2478 if (FromPointeeType->isVectorType() && ToPointeeType->isVectorType() &&
2479 Context.areCompatibleVectorTypes(FromPointeeType, ToPointeeType)) {
2480 ConvertedType = BuildSimilarlyQualifiedPointerType(FromTypePtr,
2481 ToPointeeType,
2482 ToType, Context);
2483 return true;
2484 }
2485
2486 return false;
2487 }
2488
2489 /// Adopt the given qualifiers for the given type.
AdoptQualifiers(ASTContext & Context,QualType T,Qualifiers Qs)2490 static QualType AdoptQualifiers(ASTContext &Context, QualType T, Qualifiers Qs){
2491 Qualifiers TQs = T.getQualifiers();
2492
2493 // Check whether qualifiers already match.
2494 if (TQs == Qs)
2495 return T;
2496
2497 if (Qs.compatiblyIncludes(TQs))
2498 return Context.getQualifiedType(T, Qs);
2499
2500 return Context.getQualifiedType(T.getUnqualifiedType(), Qs);
2501 }
2502
2503 /// isObjCPointerConversion - Determines whether this is an
2504 /// Objective-C pointer conversion. Subroutine of IsPointerConversion,
2505 /// with the same arguments and return values.
isObjCPointerConversion(QualType FromType,QualType ToType,QualType & ConvertedType,bool & IncompatibleObjC)2506 bool Sema::isObjCPointerConversion(QualType FromType, QualType ToType,
2507 QualType& ConvertedType,
2508 bool &IncompatibleObjC) {
2509 if (!getLangOpts().ObjC)
2510 return false;
2511
2512 // The set of qualifiers on the type we're converting from.
2513 Qualifiers FromQualifiers = FromType.getQualifiers();
2514
2515 // First, we handle all conversions on ObjC object pointer types.
2516 const ObjCObjectPointerType* ToObjCPtr =
2517 ToType->getAs<ObjCObjectPointerType>();
2518 const ObjCObjectPointerType *FromObjCPtr =
2519 FromType->getAs<ObjCObjectPointerType>();
2520
2521 if (ToObjCPtr && FromObjCPtr) {
2522 // If the pointee types are the same (ignoring qualifications),
2523 // then this is not a pointer conversion.
2524 if (Context.hasSameUnqualifiedType(ToObjCPtr->getPointeeType(),
2525 FromObjCPtr->getPointeeType()))
2526 return false;
2527
2528 // Conversion between Objective-C pointers.
2529 if (Context.canAssignObjCInterfaces(ToObjCPtr, FromObjCPtr)) {
2530 const ObjCInterfaceType* LHS = ToObjCPtr->getInterfaceType();
2531 const ObjCInterfaceType* RHS = FromObjCPtr->getInterfaceType();
2532 if (getLangOpts().CPlusPlus && LHS && RHS &&
2533 !ToObjCPtr->getPointeeType().isAtLeastAsQualifiedAs(
2534 FromObjCPtr->getPointeeType()))
2535 return false;
2536 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2537 ToObjCPtr->getPointeeType(),
2538 ToType, Context);
2539 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2540 return true;
2541 }
2542
2543 if (Context.canAssignObjCInterfaces(FromObjCPtr, ToObjCPtr)) {
2544 // Okay: this is some kind of implicit downcast of Objective-C
2545 // interfaces, which is permitted. However, we're going to
2546 // complain about it.
2547 IncompatibleObjC = true;
2548 ConvertedType = BuildSimilarlyQualifiedPointerType(FromObjCPtr,
2549 ToObjCPtr->getPointeeType(),
2550 ToType, Context);
2551 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2552 return true;
2553 }
2554 }
2555 // Beyond this point, both types need to be C pointers or block pointers.
2556 QualType ToPointeeType;
2557 if (const PointerType *ToCPtr = ToType->getAs<PointerType>())
2558 ToPointeeType = ToCPtr->getPointeeType();
2559 else if (const BlockPointerType *ToBlockPtr =
2560 ToType->getAs<BlockPointerType>()) {
2561 // Objective C++: We're able to convert from a pointer to any object
2562 // to a block pointer type.
2563 if (FromObjCPtr && FromObjCPtr->isObjCBuiltinType()) {
2564 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2565 return true;
2566 }
2567 ToPointeeType = ToBlockPtr->getPointeeType();
2568 }
2569 else if (FromType->getAs<BlockPointerType>() &&
2570 ToObjCPtr && ToObjCPtr->isObjCBuiltinType()) {
2571 // Objective C++: We're able to convert from a block pointer type to a
2572 // pointer to any object.
2573 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2574 return true;
2575 }
2576 else
2577 return false;
2578
2579 QualType FromPointeeType;
2580 if (const PointerType *FromCPtr = FromType->getAs<PointerType>())
2581 FromPointeeType = FromCPtr->getPointeeType();
2582 else if (const BlockPointerType *FromBlockPtr =
2583 FromType->getAs<BlockPointerType>())
2584 FromPointeeType = FromBlockPtr->getPointeeType();
2585 else
2586 return false;
2587
2588 // If we have pointers to pointers, recursively check whether this
2589 // is an Objective-C conversion.
2590 if (FromPointeeType->isPointerType() && ToPointeeType->isPointerType() &&
2591 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2592 IncompatibleObjC)) {
2593 // We always complain about this conversion.
2594 IncompatibleObjC = true;
2595 ConvertedType = Context.getPointerType(ConvertedType);
2596 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2597 return true;
2598 }
2599 // Allow conversion of pointee being objective-c pointer to another one;
2600 // as in I* to id.
2601 if (FromPointeeType->getAs<ObjCObjectPointerType>() &&
2602 ToPointeeType->getAs<ObjCObjectPointerType>() &&
2603 isObjCPointerConversion(FromPointeeType, ToPointeeType, ConvertedType,
2604 IncompatibleObjC)) {
2605
2606 ConvertedType = Context.getPointerType(ConvertedType);
2607 ConvertedType = AdoptQualifiers(Context, ConvertedType, FromQualifiers);
2608 return true;
2609 }
2610
2611 // If we have pointers to functions or blocks, check whether the only
2612 // differences in the argument and result types are in Objective-C
2613 // pointer conversions. If so, we permit the conversion (but
2614 // complain about it).
2615 const FunctionProtoType *FromFunctionType
2616 = FromPointeeType->getAs<FunctionProtoType>();
2617 const FunctionProtoType *ToFunctionType
2618 = ToPointeeType->getAs<FunctionProtoType>();
2619 if (FromFunctionType && ToFunctionType) {
2620 // If the function types are exactly the same, this isn't an
2621 // Objective-C pointer conversion.
2622 if (Context.getCanonicalType(FromPointeeType)
2623 == Context.getCanonicalType(ToPointeeType))
2624 return false;
2625
2626 // Perform the quick checks that will tell us whether these
2627 // function types are obviously different.
2628 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2629 FromFunctionType->isVariadic() != ToFunctionType->isVariadic() ||
2630 FromFunctionType->getMethodQuals() != ToFunctionType->getMethodQuals())
2631 return false;
2632
2633 bool HasObjCConversion = false;
2634 if (Context.getCanonicalType(FromFunctionType->getReturnType()) ==
2635 Context.getCanonicalType(ToFunctionType->getReturnType())) {
2636 // Okay, the types match exactly. Nothing to do.
2637 } else if (isObjCPointerConversion(FromFunctionType->getReturnType(),
2638 ToFunctionType->getReturnType(),
2639 ConvertedType, IncompatibleObjC)) {
2640 // Okay, we have an Objective-C pointer conversion.
2641 HasObjCConversion = true;
2642 } else {
2643 // Function types are too different. Abort.
2644 return false;
2645 }
2646
2647 // Check argument types.
2648 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2649 ArgIdx != NumArgs; ++ArgIdx) {
2650 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2651 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2652 if (Context.getCanonicalType(FromArgType)
2653 == Context.getCanonicalType(ToArgType)) {
2654 // Okay, the types match exactly. Nothing to do.
2655 } else if (isObjCPointerConversion(FromArgType, ToArgType,
2656 ConvertedType, IncompatibleObjC)) {
2657 // Okay, we have an Objective-C pointer conversion.
2658 HasObjCConversion = true;
2659 } else {
2660 // Argument types are too different. Abort.
2661 return false;
2662 }
2663 }
2664
2665 if (HasObjCConversion) {
2666 // We had an Objective-C conversion. Allow this pointer
2667 // conversion, but complain about it.
2668 ConvertedType = AdoptQualifiers(Context, ToType, FromQualifiers);
2669 IncompatibleObjC = true;
2670 return true;
2671 }
2672 }
2673
2674 return false;
2675 }
2676
2677 /// Determine whether this is an Objective-C writeback conversion,
2678 /// used for parameter passing when performing automatic reference counting.
2679 ///
2680 /// \param FromType The type we're converting form.
2681 ///
2682 /// \param ToType The type we're converting to.
2683 ///
2684 /// \param ConvertedType The type that will be produced after applying
2685 /// this conversion.
isObjCWritebackConversion(QualType FromType,QualType ToType,QualType & ConvertedType)2686 bool Sema::isObjCWritebackConversion(QualType FromType, QualType ToType,
2687 QualType &ConvertedType) {
2688 if (!getLangOpts().ObjCAutoRefCount ||
2689 Context.hasSameUnqualifiedType(FromType, ToType))
2690 return false;
2691
2692 // Parameter must be a pointer to __autoreleasing (with no other qualifiers).
2693 QualType ToPointee;
2694 if (const PointerType *ToPointer = ToType->getAs<PointerType>())
2695 ToPointee = ToPointer->getPointeeType();
2696 else
2697 return false;
2698
2699 Qualifiers ToQuals = ToPointee.getQualifiers();
2700 if (!ToPointee->isObjCLifetimeType() ||
2701 ToQuals.getObjCLifetime() != Qualifiers::OCL_Autoreleasing ||
2702 !ToQuals.withoutObjCLifetime().empty())
2703 return false;
2704
2705 // Argument must be a pointer to __strong to __weak.
2706 QualType FromPointee;
2707 if (const PointerType *FromPointer = FromType->getAs<PointerType>())
2708 FromPointee = FromPointer->getPointeeType();
2709 else
2710 return false;
2711
2712 Qualifiers FromQuals = FromPointee.getQualifiers();
2713 if (!FromPointee->isObjCLifetimeType() ||
2714 (FromQuals.getObjCLifetime() != Qualifiers::OCL_Strong &&
2715 FromQuals.getObjCLifetime() != Qualifiers::OCL_Weak))
2716 return false;
2717
2718 // Make sure that we have compatible qualifiers.
2719 FromQuals.setObjCLifetime(Qualifiers::OCL_Autoreleasing);
2720 if (!ToQuals.compatiblyIncludes(FromQuals))
2721 return false;
2722
2723 // Remove qualifiers from the pointee type we're converting from; they
2724 // aren't used in the compatibility check belong, and we'll be adding back
2725 // qualifiers (with __autoreleasing) if the compatibility check succeeds.
2726 FromPointee = FromPointee.getUnqualifiedType();
2727
2728 // The unqualified form of the pointee types must be compatible.
2729 ToPointee = ToPointee.getUnqualifiedType();
2730 bool IncompatibleObjC;
2731 if (Context.typesAreCompatible(FromPointee, ToPointee))
2732 FromPointee = ToPointee;
2733 else if (!isObjCPointerConversion(FromPointee, ToPointee, FromPointee,
2734 IncompatibleObjC))
2735 return false;
2736
2737 /// Construct the type we're converting to, which is a pointer to
2738 /// __autoreleasing pointee.
2739 FromPointee = Context.getQualifiedType(FromPointee, FromQuals);
2740 ConvertedType = Context.getPointerType(FromPointee);
2741 return true;
2742 }
2743
IsBlockPointerConversion(QualType FromType,QualType ToType,QualType & ConvertedType)2744 bool Sema::IsBlockPointerConversion(QualType FromType, QualType ToType,
2745 QualType& ConvertedType) {
2746 QualType ToPointeeType;
2747 if (const BlockPointerType *ToBlockPtr =
2748 ToType->getAs<BlockPointerType>())
2749 ToPointeeType = ToBlockPtr->getPointeeType();
2750 else
2751 return false;
2752
2753 QualType FromPointeeType;
2754 if (const BlockPointerType *FromBlockPtr =
2755 FromType->getAs<BlockPointerType>())
2756 FromPointeeType = FromBlockPtr->getPointeeType();
2757 else
2758 return false;
2759 // We have pointer to blocks, check whether the only
2760 // differences in the argument and result types are in Objective-C
2761 // pointer conversions. If so, we permit the conversion.
2762
2763 const FunctionProtoType *FromFunctionType
2764 = FromPointeeType->getAs<FunctionProtoType>();
2765 const FunctionProtoType *ToFunctionType
2766 = ToPointeeType->getAs<FunctionProtoType>();
2767
2768 if (!FromFunctionType || !ToFunctionType)
2769 return false;
2770
2771 if (Context.hasSameType(FromPointeeType, ToPointeeType))
2772 return true;
2773
2774 // Perform the quick checks that will tell us whether these
2775 // function types are obviously different.
2776 if (FromFunctionType->getNumParams() != ToFunctionType->getNumParams() ||
2777 FromFunctionType->isVariadic() != ToFunctionType->isVariadic())
2778 return false;
2779
2780 FunctionType::ExtInfo FromEInfo = FromFunctionType->getExtInfo();
2781 FunctionType::ExtInfo ToEInfo = ToFunctionType->getExtInfo();
2782 if (FromEInfo != ToEInfo)
2783 return false;
2784
2785 bool IncompatibleObjC = false;
2786 if (Context.hasSameType(FromFunctionType->getReturnType(),
2787 ToFunctionType->getReturnType())) {
2788 // Okay, the types match exactly. Nothing to do.
2789 } else {
2790 QualType RHS = FromFunctionType->getReturnType();
2791 QualType LHS = ToFunctionType->getReturnType();
2792 if ((!getLangOpts().CPlusPlus || !RHS->isRecordType()) &&
2793 !RHS.hasQualifiers() && LHS.hasQualifiers())
2794 LHS = LHS.getUnqualifiedType();
2795
2796 if (Context.hasSameType(RHS,LHS)) {
2797 // OK exact match.
2798 } else if (isObjCPointerConversion(RHS, LHS,
2799 ConvertedType, IncompatibleObjC)) {
2800 if (IncompatibleObjC)
2801 return false;
2802 // Okay, we have an Objective-C pointer conversion.
2803 }
2804 else
2805 return false;
2806 }
2807
2808 // Check argument types.
2809 for (unsigned ArgIdx = 0, NumArgs = FromFunctionType->getNumParams();
2810 ArgIdx != NumArgs; ++ArgIdx) {
2811 IncompatibleObjC = false;
2812 QualType FromArgType = FromFunctionType->getParamType(ArgIdx);
2813 QualType ToArgType = ToFunctionType->getParamType(ArgIdx);
2814 if (Context.hasSameType(FromArgType, ToArgType)) {
2815 // Okay, the types match exactly. Nothing to do.
2816 } else if (isObjCPointerConversion(ToArgType, FromArgType,
2817 ConvertedType, IncompatibleObjC)) {
2818 if (IncompatibleObjC)
2819 return false;
2820 // Okay, we have an Objective-C pointer conversion.
2821 } else
2822 // Argument types are too different. Abort.
2823 return false;
2824 }
2825
2826 SmallVector<FunctionProtoType::ExtParameterInfo, 4> NewParamInfos;
2827 bool CanUseToFPT, CanUseFromFPT;
2828 if (!Context.mergeExtParameterInfo(ToFunctionType, FromFunctionType,
2829 CanUseToFPT, CanUseFromFPT,
2830 NewParamInfos))
2831 return false;
2832
2833 ConvertedType = ToType;
2834 return true;
2835 }
2836
2837 enum {
2838 ft_default,
2839 ft_different_class,
2840 ft_parameter_arity,
2841 ft_parameter_mismatch,
2842 ft_return_type,
2843 ft_qualifer_mismatch,
2844 ft_noexcept
2845 };
2846
2847 /// Attempts to get the FunctionProtoType from a Type. Handles
2848 /// MemberFunctionPointers properly.
tryGetFunctionProtoType(QualType FromType)2849 static const FunctionProtoType *tryGetFunctionProtoType(QualType FromType) {
2850 if (auto *FPT = FromType->getAs<FunctionProtoType>())
2851 return FPT;
2852
2853 if (auto *MPT = FromType->getAs<MemberPointerType>())
2854 return MPT->getPointeeType()->getAs<FunctionProtoType>();
2855
2856 return nullptr;
2857 }
2858
2859 /// HandleFunctionTypeMismatch - Gives diagnostic information for differeing
2860 /// function types. Catches different number of parameter, mismatch in
2861 /// parameter types, and different return types.
HandleFunctionTypeMismatch(PartialDiagnostic & PDiag,QualType FromType,QualType ToType)2862 void Sema::HandleFunctionTypeMismatch(PartialDiagnostic &PDiag,
2863 QualType FromType, QualType ToType) {
2864 // If either type is not valid, include no extra info.
2865 if (FromType.isNull() || ToType.isNull()) {
2866 PDiag << ft_default;
2867 return;
2868 }
2869
2870 // Get the function type from the pointers.
2871 if (FromType->isMemberPointerType() && ToType->isMemberPointerType()) {
2872 const auto *FromMember = FromType->castAs<MemberPointerType>(),
2873 *ToMember = ToType->castAs<MemberPointerType>();
2874 if (!Context.hasSameType(FromMember->getClass(), ToMember->getClass())) {
2875 PDiag << ft_different_class << QualType(ToMember->getClass(), 0)
2876 << QualType(FromMember->getClass(), 0);
2877 return;
2878 }
2879 FromType = FromMember->getPointeeType();
2880 ToType = ToMember->getPointeeType();
2881 }
2882
2883 if (FromType->isPointerType())
2884 FromType = FromType->getPointeeType();
2885 if (ToType->isPointerType())
2886 ToType = ToType->getPointeeType();
2887
2888 // Remove references.
2889 FromType = FromType.getNonReferenceType();
2890 ToType = ToType.getNonReferenceType();
2891
2892 // Don't print extra info for non-specialized template functions.
2893 if (FromType->isInstantiationDependentType() &&
2894 !FromType->getAs<TemplateSpecializationType>()) {
2895 PDiag << ft_default;
2896 return;
2897 }
2898
2899 // No extra info for same types.
2900 if (Context.hasSameType(FromType, ToType)) {
2901 PDiag << ft_default;
2902 return;
2903 }
2904
2905 const FunctionProtoType *FromFunction = tryGetFunctionProtoType(FromType),
2906 *ToFunction = tryGetFunctionProtoType(ToType);
2907
2908 // Both types need to be function types.
2909 if (!FromFunction || !ToFunction) {
2910 PDiag << ft_default;
2911 return;
2912 }
2913
2914 if (FromFunction->getNumParams() != ToFunction->getNumParams()) {
2915 PDiag << ft_parameter_arity << ToFunction->getNumParams()
2916 << FromFunction->getNumParams();
2917 return;
2918 }
2919
2920 // Handle different parameter types.
2921 unsigned ArgPos;
2922 if (!FunctionParamTypesAreEqual(FromFunction, ToFunction, &ArgPos)) {
2923 PDiag << ft_parameter_mismatch << ArgPos + 1
2924 << ToFunction->getParamType(ArgPos)
2925 << FromFunction->getParamType(ArgPos);
2926 return;
2927 }
2928
2929 // Handle different return type.
2930 if (!Context.hasSameType(FromFunction->getReturnType(),
2931 ToFunction->getReturnType())) {
2932 PDiag << ft_return_type << ToFunction->getReturnType()
2933 << FromFunction->getReturnType();
2934 return;
2935 }
2936
2937 if (FromFunction->getMethodQuals() != ToFunction->getMethodQuals()) {
2938 PDiag << ft_qualifer_mismatch << ToFunction->getMethodQuals()
2939 << FromFunction->getMethodQuals();
2940 return;
2941 }
2942
2943 // Handle exception specification differences on canonical type (in C++17
2944 // onwards).
2945 if (cast<FunctionProtoType>(FromFunction->getCanonicalTypeUnqualified())
2946 ->isNothrow() !=
2947 cast<FunctionProtoType>(ToFunction->getCanonicalTypeUnqualified())
2948 ->isNothrow()) {
2949 PDiag << ft_noexcept;
2950 return;
2951 }
2952
2953 // Unable to find a difference, so add no extra info.
2954 PDiag << ft_default;
2955 }
2956
2957 /// FunctionParamTypesAreEqual - This routine checks two function proto types
2958 /// for equality of their argument types. Caller has already checked that
2959 /// they have same number of arguments. If the parameters are different,
2960 /// ArgPos will have the parameter index of the first different parameter.
FunctionParamTypesAreEqual(const FunctionProtoType * OldType,const FunctionProtoType * NewType,unsigned * ArgPos)2961 bool Sema::FunctionParamTypesAreEqual(const FunctionProtoType *OldType,
2962 const FunctionProtoType *NewType,
2963 unsigned *ArgPos) {
2964 for (FunctionProtoType::param_type_iterator O = OldType->param_type_begin(),
2965 N = NewType->param_type_begin(),
2966 E = OldType->param_type_end();
2967 O && (O != E); ++O, ++N) {
2968 // Ignore address spaces in pointee type. This is to disallow overloading
2969 // on __ptr32/__ptr64 address spaces.
2970 QualType Old = Context.removePtrSizeAddrSpace(O->getUnqualifiedType());
2971 QualType New = Context.removePtrSizeAddrSpace(N->getUnqualifiedType());
2972
2973 if (!Context.hasSameType(Old, New)) {
2974 if (ArgPos)
2975 *ArgPos = O - OldType->param_type_begin();
2976 return false;
2977 }
2978 }
2979 return true;
2980 }
2981
2982 /// CheckPointerConversion - Check the pointer conversion from the
2983 /// expression From to the type ToType. This routine checks for
2984 /// ambiguous or inaccessible derived-to-base pointer
2985 /// conversions for which IsPointerConversion has already returned
2986 /// true. It returns true and produces a diagnostic if there was an
2987 /// error, or returns false otherwise.
CheckPointerConversion(Expr * From,QualType ToType,CastKind & Kind,CXXCastPath & BasePath,bool IgnoreBaseAccess,bool Diagnose)2988 bool Sema::CheckPointerConversion(Expr *From, QualType ToType,
2989 CastKind &Kind,
2990 CXXCastPath& BasePath,
2991 bool IgnoreBaseAccess,
2992 bool Diagnose) {
2993 QualType FromType = From->getType();
2994 bool IsCStyleOrFunctionalCast = IgnoreBaseAccess;
2995
2996 Kind = CK_BitCast;
2997
2998 if (Diagnose && !IsCStyleOrFunctionalCast && !FromType->isAnyPointerType() &&
2999 From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNotNull) ==
3000 Expr::NPCK_ZeroExpression) {
3001 if (Context.hasSameUnqualifiedType(From->getType(), Context.BoolTy))
3002 DiagRuntimeBehavior(From->getExprLoc(), From,
3003 PDiag(diag::warn_impcast_bool_to_null_pointer)
3004 << ToType << From->getSourceRange());
3005 else if (!isUnevaluatedContext())
3006 Diag(From->getExprLoc(), diag::warn_non_literal_null_pointer)
3007 << ToType << From->getSourceRange();
3008 }
3009 if (const PointerType *ToPtrType = ToType->getAs<PointerType>()) {
3010 if (const PointerType *FromPtrType = FromType->getAs<PointerType>()) {
3011 QualType FromPointeeType = FromPtrType->getPointeeType(),
3012 ToPointeeType = ToPtrType->getPointeeType();
3013
3014 if (FromPointeeType->isRecordType() && ToPointeeType->isRecordType() &&
3015 !Context.hasSameUnqualifiedType(FromPointeeType, ToPointeeType)) {
3016 // We must have a derived-to-base conversion. Check an
3017 // ambiguous or inaccessible conversion.
3018 unsigned InaccessibleID = 0;
3019 unsigned AmbiguousID = 0;
3020 if (Diagnose) {
3021 InaccessibleID = diag::err_upcast_to_inaccessible_base;
3022 AmbiguousID = diag::err_ambiguous_derived_to_base_conv;
3023 }
3024 if (CheckDerivedToBaseConversion(
3025 FromPointeeType, ToPointeeType, InaccessibleID, AmbiguousID,
3026 From->getExprLoc(), From->getSourceRange(), DeclarationName(),
3027 &BasePath, IgnoreBaseAccess))
3028 return true;
3029
3030 // The conversion was successful.
3031 Kind = CK_DerivedToBase;
3032 }
3033
3034 if (Diagnose && !IsCStyleOrFunctionalCast &&
3035 FromPointeeType->isFunctionType() && ToPointeeType->isVoidType()) {
3036 assert(getLangOpts().MSVCCompat &&
3037 "this should only be possible with MSVCCompat!");
3038 Diag(From->getExprLoc(), diag::ext_ms_impcast_fn_obj)
3039 << From->getSourceRange();
3040 }
3041 }
3042 } else if (const ObjCObjectPointerType *ToPtrType =
3043 ToType->getAs<ObjCObjectPointerType>()) {
3044 if (const ObjCObjectPointerType *FromPtrType =
3045 FromType->getAs<ObjCObjectPointerType>()) {
3046 // Objective-C++ conversions are always okay.
3047 // FIXME: We should have a different class of conversions for the
3048 // Objective-C++ implicit conversions.
3049 if (FromPtrType->isObjCBuiltinType() || ToPtrType->isObjCBuiltinType())
3050 return false;
3051 } else if (FromType->isBlockPointerType()) {
3052 Kind = CK_BlockPointerToObjCPointerCast;
3053 } else {
3054 Kind = CK_CPointerToObjCPointerCast;
3055 }
3056 } else if (ToType->isBlockPointerType()) {
3057 if (!FromType->isBlockPointerType())
3058 Kind = CK_AnyPointerToBlockPointerCast;
3059 }
3060
3061 // We shouldn't fall into this case unless it's valid for other
3062 // reasons.
3063 if (From->isNullPointerConstant(Context, Expr::NPC_ValueDependentIsNull))
3064 Kind = CK_NullToPointer;
3065
3066 return false;
3067 }
3068
3069 /// IsMemberPointerConversion - Determines whether the conversion of the
3070 /// expression From, which has the (possibly adjusted) type FromType, can be
3071 /// converted to the type ToType via a member pointer conversion (C++ 4.11).
3072 /// If so, returns true and places the converted type (that might differ from
3073 /// ToType in its cv-qualifiers at some level) into ConvertedType.
IsMemberPointerConversion(Expr * From,QualType FromType,QualType ToType,bool InOverloadResolution,QualType & ConvertedType)3074 bool Sema::IsMemberPointerConversion(Expr *From, QualType FromType,
3075 QualType ToType,
3076 bool InOverloadResolution,
3077 QualType &ConvertedType) {
3078 const MemberPointerType *ToTypePtr = ToType->getAs<MemberPointerType>();
3079 if (!ToTypePtr)
3080 return false;
3081
3082 // A null pointer constant can be converted to a member pointer (C++ 4.11p1)
3083 if (From->isNullPointerConstant(Context,
3084 InOverloadResolution? Expr::NPC_ValueDependentIsNotNull
3085 : Expr::NPC_ValueDependentIsNull)) {
3086 ConvertedType = ToType;
3087 return true;
3088 }
3089
3090 // Otherwise, both types have to be member pointers.
3091 const MemberPointerType *FromTypePtr = FromType->getAs<MemberPointerType>();
3092 if (!FromTypePtr)
3093 return false;
3094
3095 // A pointer to member of B can be converted to a pointer to member of D,
3096 // where D is derived from B (C++ 4.11p2).
3097 QualType FromClass(FromTypePtr->getClass(), 0);
3098 QualType ToClass(ToTypePtr->getClass(), 0);
3099
3100 if (!Context.hasSameUnqualifiedType(FromClass, ToClass) &&
3101 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass)) {
3102 ConvertedType = Context.getMemberPointerType(FromTypePtr->getPointeeType(),
3103 ToClass.getTypePtr());
3104 return true;
3105 }
3106
3107 return false;
3108 }
3109
3110 /// CheckMemberPointerConversion - Check the member pointer conversion from the
3111 /// expression From to the type ToType. This routine checks for ambiguous or
3112 /// virtual or inaccessible base-to-derived member pointer conversions
3113 /// for which IsMemberPointerConversion has already returned true. It returns
3114 /// true and produces a diagnostic if there was an error, or returns false
3115 /// otherwise.
CheckMemberPointerConversion(Expr * From,QualType ToType,CastKind & Kind,CXXCastPath & BasePath,bool IgnoreBaseAccess)3116 bool Sema::CheckMemberPointerConversion(Expr *From, QualType ToType,
3117 CastKind &Kind,
3118 CXXCastPath &BasePath,
3119 bool IgnoreBaseAccess) {
3120 QualType FromType = From->getType();
3121 const MemberPointerType *FromPtrType = FromType->getAs<MemberPointerType>();
3122 if (!FromPtrType) {
3123 // This must be a null pointer to member pointer conversion
3124 assert(From->isNullPointerConstant(Context,
3125 Expr::NPC_ValueDependentIsNull) &&
3126 "Expr must be null pointer constant!");
3127 Kind = CK_NullToMemberPointer;
3128 return false;
3129 }
3130
3131 const MemberPointerType *ToPtrType = ToType->getAs<MemberPointerType>();
3132 assert(ToPtrType && "No member pointer cast has a target type "
3133 "that is not a member pointer.");
3134
3135 QualType FromClass = QualType(FromPtrType->getClass(), 0);
3136 QualType ToClass = QualType(ToPtrType->getClass(), 0);
3137
3138 // FIXME: What about dependent types?
3139 assert(FromClass->isRecordType() && "Pointer into non-class.");
3140 assert(ToClass->isRecordType() && "Pointer into non-class.");
3141
3142 CXXBasePaths Paths(/*FindAmbiguities=*/true, /*RecordPaths=*/true,
3143 /*DetectVirtual=*/true);
3144 bool DerivationOkay =
3145 IsDerivedFrom(From->getBeginLoc(), ToClass, FromClass, Paths);
3146 assert(DerivationOkay &&
3147 "Should not have been called if derivation isn't OK.");
3148 (void)DerivationOkay;
3149
3150 if (Paths.isAmbiguous(Context.getCanonicalType(FromClass).
3151 getUnqualifiedType())) {
3152 std::string PathDisplayStr = getAmbiguousPathsDisplayString(Paths);
3153 Diag(From->getExprLoc(), diag::err_ambiguous_memptr_conv)
3154 << 0 << FromClass << ToClass << PathDisplayStr << From->getSourceRange();
3155 return true;
3156 }
3157
3158 if (const RecordType *VBase = Paths.getDetectedVirtual()) {
3159 Diag(From->getExprLoc(), diag::err_memptr_conv_via_virtual)
3160 << FromClass << ToClass << QualType(VBase, 0)
3161 << From->getSourceRange();
3162 return true;
3163 }
3164
3165 if (!IgnoreBaseAccess)
3166 CheckBaseClassAccess(From->getExprLoc(), FromClass, ToClass,
3167 Paths.front(),
3168 diag::err_downcast_from_inaccessible_base);
3169
3170 // Must be a base to derived member conversion.
3171 BuildBasePathArray(Paths, BasePath);
3172 Kind = CK_BaseToDerivedMemberPointer;
3173 return false;
3174 }
3175
3176 /// Determine whether the lifetime conversion between the two given
3177 /// qualifiers sets is nontrivial.
isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,Qualifiers ToQuals)3178 static bool isNonTrivialObjCLifetimeConversion(Qualifiers FromQuals,
3179 Qualifiers ToQuals) {
3180 // Converting anything to const __unsafe_unretained is trivial.
3181 if (ToQuals.hasConst() &&
3182 ToQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone)
3183 return false;
3184
3185 return true;
3186 }
3187
3188 /// Perform a single iteration of the loop for checking if a qualification
3189 /// conversion is valid.
3190 ///
3191 /// Specifically, check whether any change between the qualifiers of \p
3192 /// FromType and \p ToType is permissible, given knowledge about whether every
3193 /// outer layer is const-qualified.
isQualificationConversionStep(QualType FromType,QualType ToType,bool CStyle,bool IsTopLevel,bool & PreviousToQualsIncludeConst,bool & ObjCLifetimeConversion)3194 static bool isQualificationConversionStep(QualType FromType, QualType ToType,
3195 bool CStyle, bool IsTopLevel,
3196 bool &PreviousToQualsIncludeConst,
3197 bool &ObjCLifetimeConversion) {
3198 Qualifiers FromQuals = FromType.getQualifiers();
3199 Qualifiers ToQuals = ToType.getQualifiers();
3200
3201 // Ignore __unaligned qualifier if this type is void.
3202 if (ToType.getUnqualifiedType()->isVoidType())
3203 FromQuals.removeUnaligned();
3204
3205 // Objective-C ARC:
3206 // Check Objective-C lifetime conversions.
3207 if (FromQuals.getObjCLifetime() != ToQuals.getObjCLifetime()) {
3208 if (ToQuals.compatiblyIncludesObjCLifetime(FromQuals)) {
3209 if (isNonTrivialObjCLifetimeConversion(FromQuals, ToQuals))
3210 ObjCLifetimeConversion = true;
3211 FromQuals.removeObjCLifetime();
3212 ToQuals.removeObjCLifetime();
3213 } else {
3214 // Qualification conversions cannot cast between different
3215 // Objective-C lifetime qualifiers.
3216 return false;
3217 }
3218 }
3219
3220 // Allow addition/removal of GC attributes but not changing GC attributes.
3221 if (FromQuals.getObjCGCAttr() != ToQuals.getObjCGCAttr() &&
3222 (!FromQuals.hasObjCGCAttr() || !ToQuals.hasObjCGCAttr())) {
3223 FromQuals.removeObjCGCAttr();
3224 ToQuals.removeObjCGCAttr();
3225 }
3226
3227 // -- for every j > 0, if const is in cv 1,j then const is in cv
3228 // 2,j, and similarly for volatile.
3229 if (!CStyle && !ToQuals.compatiblyIncludes(FromQuals))
3230 return false;
3231
3232 // If address spaces mismatch:
3233 // - in top level it is only valid to convert to addr space that is a
3234 // superset in all cases apart from C-style casts where we allow
3235 // conversions between overlapping address spaces.
3236 // - in non-top levels it is not a valid conversion.
3237 if (ToQuals.getAddressSpace() != FromQuals.getAddressSpace() &&
3238 (!IsTopLevel ||
3239 !(ToQuals.isAddressSpaceSupersetOf(FromQuals) ||
3240 (CStyle && FromQuals.isAddressSpaceSupersetOf(ToQuals)))))
3241 return false;
3242
3243 // -- if the cv 1,j and cv 2,j are different, then const is in
3244 // every cv for 0 < k < j.
3245 if (!CStyle && FromQuals.getCVRQualifiers() != ToQuals.getCVRQualifiers() &&
3246 !PreviousToQualsIncludeConst)
3247 return false;
3248
3249 // The following wording is from C++20, where the result of the conversion
3250 // is T3, not T2.
3251 // -- if [...] P1,i [...] is "array of unknown bound of", P3,i is
3252 // "array of unknown bound of"
3253 if (FromType->isIncompleteArrayType() && !ToType->isIncompleteArrayType())
3254 return false;
3255
3256 // -- if the resulting P3,i is different from P1,i [...], then const is
3257 // added to every cv 3_k for 0 < k < i.
3258 if (!CStyle && FromType->isConstantArrayType() &&
3259 ToType->isIncompleteArrayType() && !PreviousToQualsIncludeConst)
3260 return false;
3261
3262 // Keep track of whether all prior cv-qualifiers in the "to" type
3263 // include const.
3264 PreviousToQualsIncludeConst =
3265 PreviousToQualsIncludeConst && ToQuals.hasConst();
3266 return true;
3267 }
3268
3269 /// IsQualificationConversion - Determines whether the conversion from
3270 /// an rvalue of type FromType to ToType is a qualification conversion
3271 /// (C++ 4.4).
3272 ///
3273 /// \param ObjCLifetimeConversion Output parameter that will be set to indicate
3274 /// when the qualification conversion involves a change in the Objective-C
3275 /// object lifetime.
3276 bool
IsQualificationConversion(QualType FromType,QualType ToType,bool CStyle,bool & ObjCLifetimeConversion)3277 Sema::IsQualificationConversion(QualType FromType, QualType ToType,
3278 bool CStyle, bool &ObjCLifetimeConversion) {
3279 FromType = Context.getCanonicalType(FromType);
3280 ToType = Context.getCanonicalType(ToType);
3281 ObjCLifetimeConversion = false;
3282
3283 // If FromType and ToType are the same type, this is not a
3284 // qualification conversion.
3285 if (FromType.getUnqualifiedType() == ToType.getUnqualifiedType())
3286 return false;
3287
3288 // (C++ 4.4p4):
3289 // A conversion can add cv-qualifiers at levels other than the first
3290 // in multi-level pointers, subject to the following rules: [...]
3291 bool PreviousToQualsIncludeConst = true;
3292 bool UnwrappedAnyPointer = false;
3293 while (Context.UnwrapSimilarTypes(FromType, ToType)) {
3294 if (!isQualificationConversionStep(
3295 FromType, ToType, CStyle, !UnwrappedAnyPointer,
3296 PreviousToQualsIncludeConst, ObjCLifetimeConversion))
3297 return false;
3298 UnwrappedAnyPointer = true;
3299 }
3300
3301 // We are left with FromType and ToType being the pointee types
3302 // after unwrapping the original FromType and ToType the same number
3303 // of times. If we unwrapped any pointers, and if FromType and
3304 // ToType have the same unqualified type (since we checked
3305 // qualifiers above), then this is a qualification conversion.
3306 return UnwrappedAnyPointer && Context.hasSameUnqualifiedType(FromType,ToType);
3307 }
3308
3309 /// - Determine whether this is a conversion from a scalar type to an
3310 /// atomic type.
3311 ///
3312 /// If successful, updates \c SCS's second and third steps in the conversion
3313 /// sequence to finish the conversion.
tryAtomicConversion(Sema & S,Expr * From,QualType ToType,bool InOverloadResolution,StandardConversionSequence & SCS,bool CStyle)3314 static bool tryAtomicConversion(Sema &S, Expr *From, QualType ToType,
3315 bool InOverloadResolution,
3316 StandardConversionSequence &SCS,
3317 bool CStyle) {
3318 const AtomicType *ToAtomic = ToType->getAs<AtomicType>();
3319 if (!ToAtomic)
3320 return false;
3321
3322 StandardConversionSequence InnerSCS;
3323 if (!IsStandardConversion(S, From, ToAtomic->getValueType(),
3324 InOverloadResolution, InnerSCS,
3325 CStyle, /*AllowObjCWritebackConversion=*/false))
3326 return false;
3327
3328 SCS.Second = InnerSCS.Second;
3329 SCS.setToType(1, InnerSCS.getToType(1));
3330 SCS.Third = InnerSCS.Third;
3331 SCS.QualificationIncludesObjCLifetime
3332 = InnerSCS.QualificationIncludesObjCLifetime;
3333 SCS.setToType(2, InnerSCS.getToType(2));
3334 return true;
3335 }
3336
isFirstArgumentCompatibleWithType(ASTContext & Context,CXXConstructorDecl * Constructor,QualType Type)3337 static bool isFirstArgumentCompatibleWithType(ASTContext &Context,
3338 CXXConstructorDecl *Constructor,
3339 QualType Type) {
3340 const auto *CtorType = Constructor->getType()->castAs<FunctionProtoType>();
3341 if (CtorType->getNumParams() > 0) {
3342 QualType FirstArg = CtorType->getParamType(0);
3343 if (Context.hasSameUnqualifiedType(Type, FirstArg.getNonReferenceType()))
3344 return true;
3345 }
3346 return false;
3347 }
3348
3349 static OverloadingResult
IsInitializerListConstructorConversion(Sema & S,Expr * From,QualType ToType,CXXRecordDecl * To,UserDefinedConversionSequence & User,OverloadCandidateSet & CandidateSet,bool AllowExplicit)3350 IsInitializerListConstructorConversion(Sema &S, Expr *From, QualType ToType,
3351 CXXRecordDecl *To,
3352 UserDefinedConversionSequence &User,
3353 OverloadCandidateSet &CandidateSet,
3354 bool AllowExplicit) {
3355 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3356 for (auto *D : S.LookupConstructors(To)) {
3357 auto Info = getConstructorInfo(D);
3358 if (!Info)
3359 continue;
3360
3361 bool Usable = !Info.Constructor->isInvalidDecl() &&
3362 S.isInitListConstructor(Info.Constructor);
3363 if (Usable) {
3364 bool SuppressUserConversions = false;
3365 if (Info.ConstructorTmpl)
3366 S.AddTemplateOverloadCandidate(Info.ConstructorTmpl, Info.FoundDecl,
3367 /*ExplicitArgs*/ nullptr, From,
3368 CandidateSet, SuppressUserConversions,
3369 /*PartialOverloading*/ false,
3370 AllowExplicit);
3371 else
3372 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl, From,
3373 CandidateSet, SuppressUserConversions,
3374 /*PartialOverloading*/ false, AllowExplicit);
3375 }
3376 }
3377
3378 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3379
3380 OverloadCandidateSet::iterator Best;
3381 switch (auto Result =
3382 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3383 case OR_Deleted:
3384 case OR_Success: {
3385 // Record the standard conversion we used and the conversion function.
3386 CXXConstructorDecl *Constructor = cast<CXXConstructorDecl>(Best->Function);
3387 QualType ThisType = Constructor->getThisType();
3388 // Initializer lists don't have conversions as such.
3389 User.Before.setAsIdentityConversion();
3390 User.HadMultipleCandidates = HadMultipleCandidates;
3391 User.ConversionFunction = Constructor;
3392 User.FoundConversionFunction = Best->FoundDecl;
3393 User.After.setAsIdentityConversion();
3394 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3395 User.After.setAllToTypes(ToType);
3396 return Result;
3397 }
3398
3399 case OR_No_Viable_Function:
3400 return OR_No_Viable_Function;
3401 case OR_Ambiguous:
3402 return OR_Ambiguous;
3403 }
3404
3405 llvm_unreachable("Invalid OverloadResult!");
3406 }
3407
3408 /// Determines whether there is a user-defined conversion sequence
3409 /// (C++ [over.ics.user]) that converts expression From to the type
3410 /// ToType. If such a conversion exists, User will contain the
3411 /// user-defined conversion sequence that performs such a conversion
3412 /// and this routine will return true. Otherwise, this routine returns
3413 /// false and User is unspecified.
3414 ///
3415 /// \param AllowExplicit true if the conversion should consider C++0x
3416 /// "explicit" conversion functions as well as non-explicit conversion
3417 /// functions (C++0x [class.conv.fct]p2).
3418 ///
3419 /// \param AllowObjCConversionOnExplicit true if the conversion should
3420 /// allow an extra Objective-C pointer conversion on uses of explicit
3421 /// constructors. Requires \c AllowExplicit to also be set.
3422 static OverloadingResult
IsUserDefinedConversion(Sema & S,Expr * From,QualType ToType,UserDefinedConversionSequence & User,OverloadCandidateSet & CandidateSet,AllowedExplicit AllowExplicit,bool AllowObjCConversionOnExplicit)3423 IsUserDefinedConversion(Sema &S, Expr *From, QualType ToType,
3424 UserDefinedConversionSequence &User,
3425 OverloadCandidateSet &CandidateSet,
3426 AllowedExplicit AllowExplicit,
3427 bool AllowObjCConversionOnExplicit) {
3428 assert(AllowExplicit != AllowedExplicit::None ||
3429 !AllowObjCConversionOnExplicit);
3430 CandidateSet.clear(OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3431
3432 // Whether we will only visit constructors.
3433 bool ConstructorsOnly = false;
3434
3435 // If the type we are conversion to is a class type, enumerate its
3436 // constructors.
3437 if (const RecordType *ToRecordType = ToType->getAs<RecordType>()) {
3438 // C++ [over.match.ctor]p1:
3439 // When objects of class type are direct-initialized (8.5), or
3440 // copy-initialized from an expression of the same or a
3441 // derived class type (8.5), overload resolution selects the
3442 // constructor. [...] For copy-initialization, the candidate
3443 // functions are all the converting constructors (12.3.1) of
3444 // that class. The argument list is the expression-list within
3445 // the parentheses of the initializer.
3446 if (S.Context.hasSameUnqualifiedType(ToType, From->getType()) ||
3447 (From->getType()->getAs<RecordType>() &&
3448 S.IsDerivedFrom(From->getBeginLoc(), From->getType(), ToType)))
3449 ConstructorsOnly = true;
3450
3451 if (!S.isCompleteType(From->getExprLoc(), ToType)) {
3452 // We're not going to find any constructors.
3453 } else if (CXXRecordDecl *ToRecordDecl
3454 = dyn_cast<CXXRecordDecl>(ToRecordType->getDecl())) {
3455
3456 Expr **Args = &From;
3457 unsigned NumArgs = 1;
3458 bool ListInitializing = false;
3459 if (InitListExpr *InitList = dyn_cast<InitListExpr>(From)) {
3460 // But first, see if there is an init-list-constructor that will work.
3461 OverloadingResult Result = IsInitializerListConstructorConversion(
3462 S, From, ToType, ToRecordDecl, User, CandidateSet,
3463 AllowExplicit == AllowedExplicit::All);
3464 if (Result != OR_No_Viable_Function)
3465 return Result;
3466 // Never mind.
3467 CandidateSet.clear(
3468 OverloadCandidateSet::CSK_InitByUserDefinedConversion);
3469
3470 // If we're list-initializing, we pass the individual elements as
3471 // arguments, not the entire list.
3472 Args = InitList->getInits();
3473 NumArgs = InitList->getNumInits();
3474 ListInitializing = true;
3475 }
3476
3477 for (auto *D : S.LookupConstructors(ToRecordDecl)) {
3478 auto Info = getConstructorInfo(D);
3479 if (!Info)
3480 continue;
3481
3482 bool Usable = !Info.Constructor->isInvalidDecl();
3483 if (!ListInitializing)
3484 Usable = Usable && Info.Constructor->isConvertingConstructor(
3485 /*AllowExplicit*/ true);
3486 if (Usable) {
3487 bool SuppressUserConversions = !ConstructorsOnly;
3488 // C++20 [over.best.ics.general]/4.5:
3489 // if the target is the first parameter of a constructor [of class
3490 // X] and the constructor [...] is a candidate by [...] the second
3491 // phase of [over.match.list] when the initializer list has exactly
3492 // one element that is itself an initializer list, [...] and the
3493 // conversion is to X or reference to cv X, user-defined conversion
3494 // sequences are not cnosidered.
3495 if (SuppressUserConversions && ListInitializing) {
3496 SuppressUserConversions =
3497 NumArgs == 1 && isa<InitListExpr>(Args[0]) &&
3498 isFirstArgumentCompatibleWithType(S.Context, Info.Constructor,
3499 ToType);
3500 }
3501 if (Info.ConstructorTmpl)
3502 S.AddTemplateOverloadCandidate(
3503 Info.ConstructorTmpl, Info.FoundDecl,
3504 /*ExplicitArgs*/ nullptr, llvm::makeArrayRef(Args, NumArgs),
3505 CandidateSet, SuppressUserConversions,
3506 /*PartialOverloading*/ false,
3507 AllowExplicit == AllowedExplicit::All);
3508 else
3509 // Allow one user-defined conversion when user specifies a
3510 // From->ToType conversion via an static cast (c-style, etc).
3511 S.AddOverloadCandidate(Info.Constructor, Info.FoundDecl,
3512 llvm::makeArrayRef(Args, NumArgs),
3513 CandidateSet, SuppressUserConversions,
3514 /*PartialOverloading*/ false,
3515 AllowExplicit == AllowedExplicit::All);
3516 }
3517 }
3518 }
3519 }
3520
3521 // Enumerate conversion functions, if we're allowed to.
3522 if (ConstructorsOnly || isa<InitListExpr>(From)) {
3523 } else if (!S.isCompleteType(From->getBeginLoc(), From->getType())) {
3524 // No conversion functions from incomplete types.
3525 } else if (const RecordType *FromRecordType =
3526 From->getType()->getAs<RecordType>()) {
3527 if (CXXRecordDecl *FromRecordDecl
3528 = dyn_cast<CXXRecordDecl>(FromRecordType->getDecl())) {
3529 // Add all of the conversion functions as candidates.
3530 const auto &Conversions = FromRecordDecl->getVisibleConversionFunctions();
3531 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
3532 DeclAccessPair FoundDecl = I.getPair();
3533 NamedDecl *D = FoundDecl.getDecl();
3534 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
3535 if (isa<UsingShadowDecl>(D))
3536 D = cast<UsingShadowDecl>(D)->getTargetDecl();
3537
3538 CXXConversionDecl *Conv;
3539 FunctionTemplateDecl *ConvTemplate;
3540 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
3541 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
3542 else
3543 Conv = cast<CXXConversionDecl>(D);
3544
3545 if (ConvTemplate)
3546 S.AddTemplateConversionCandidate(
3547 ConvTemplate, FoundDecl, ActingContext, From, ToType,
3548 CandidateSet, AllowObjCConversionOnExplicit,
3549 AllowExplicit != AllowedExplicit::None);
3550 else
3551 S.AddConversionCandidate(Conv, FoundDecl, ActingContext, From, ToType,
3552 CandidateSet, AllowObjCConversionOnExplicit,
3553 AllowExplicit != AllowedExplicit::None);
3554 }
3555 }
3556 }
3557
3558 bool HadMultipleCandidates = (CandidateSet.size() > 1);
3559
3560 OverloadCandidateSet::iterator Best;
3561 switch (auto Result =
3562 CandidateSet.BestViableFunction(S, From->getBeginLoc(), Best)) {
3563 case OR_Success:
3564 case OR_Deleted:
3565 // Record the standard conversion we used and the conversion function.
3566 if (CXXConstructorDecl *Constructor
3567 = dyn_cast<CXXConstructorDecl>(Best->Function)) {
3568 // C++ [over.ics.user]p1:
3569 // If the user-defined conversion is specified by a
3570 // constructor (12.3.1), the initial standard conversion
3571 // sequence converts the source type to the type required by
3572 // the argument of the constructor.
3573 //
3574 QualType ThisType = Constructor->getThisType();
3575 if (isa<InitListExpr>(From)) {
3576 // Initializer lists don't have conversions as such.
3577 User.Before.setAsIdentityConversion();
3578 } else {
3579 if (Best->Conversions[0].isEllipsis())
3580 User.EllipsisConversion = true;
3581 else {
3582 User.Before = Best->Conversions[0].Standard;
3583 User.EllipsisConversion = false;
3584 }
3585 }
3586 User.HadMultipleCandidates = HadMultipleCandidates;
3587 User.ConversionFunction = Constructor;
3588 User.FoundConversionFunction = Best->FoundDecl;
3589 User.After.setAsIdentityConversion();
3590 User.After.setFromType(ThisType->castAs<PointerType>()->getPointeeType());
3591 User.After.setAllToTypes(ToType);
3592 return Result;
3593 }
3594 if (CXXConversionDecl *Conversion
3595 = dyn_cast<CXXConversionDecl>(Best->Function)) {
3596 // C++ [over.ics.user]p1:
3597 //
3598 // [...] If the user-defined conversion is specified by a
3599 // conversion function (12.3.2), the initial standard
3600 // conversion sequence converts the source type to the
3601 // implicit object parameter of the conversion function.
3602 User.Before = Best->Conversions[0].Standard;
3603 User.HadMultipleCandidates = HadMultipleCandidates;
3604 User.ConversionFunction = Conversion;
3605 User.FoundConversionFunction = Best->FoundDecl;
3606 User.EllipsisConversion = false;
3607
3608 // C++ [over.ics.user]p2:
3609 // The second standard conversion sequence converts the
3610 // result of the user-defined conversion to the target type
3611 // for the sequence. Since an implicit conversion sequence
3612 // is an initialization, the special rules for
3613 // initialization by user-defined conversion apply when
3614 // selecting the best user-defined conversion for a
3615 // user-defined conversion sequence (see 13.3.3 and
3616 // 13.3.3.1).
3617 User.After = Best->FinalConversion;
3618 return Result;
3619 }
3620 llvm_unreachable("Not a constructor or conversion function?");
3621
3622 case OR_No_Viable_Function:
3623 return OR_No_Viable_Function;
3624
3625 case OR_Ambiguous:
3626 return OR_Ambiguous;
3627 }
3628
3629 llvm_unreachable("Invalid OverloadResult!");
3630 }
3631
3632 bool
DiagnoseMultipleUserDefinedConversion(Expr * From,QualType ToType)3633 Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
3634 ImplicitConversionSequence ICS;
3635 OverloadCandidateSet CandidateSet(From->getExprLoc(),
3636 OverloadCandidateSet::CSK_Normal);
3637 OverloadingResult OvResult =
3638 IsUserDefinedConversion(*this, From, ToType, ICS.UserDefined,
3639 CandidateSet, AllowedExplicit::None, false);
3640
3641 if (!(OvResult == OR_Ambiguous ||
3642 (OvResult == OR_No_Viable_Function && !CandidateSet.empty())))
3643 return false;
3644
3645 auto Cands = CandidateSet.CompleteCandidates(
3646 *this,
3647 OvResult == OR_Ambiguous ? OCD_AmbiguousCandidates : OCD_AllCandidates,
3648 From);
3649 if (OvResult == OR_Ambiguous)
3650 Diag(From->getBeginLoc(), diag::err_typecheck_ambiguous_condition)
3651 << From->getType() << ToType << From->getSourceRange();
3652 else { // OR_No_Viable_Function && !CandidateSet.empty()
3653 if (!RequireCompleteType(From->getBeginLoc(), ToType,
3654 diag::err_typecheck_nonviable_condition_incomplete,
3655 From->getType(), From->getSourceRange()))
3656 Diag(From->getBeginLoc(), diag::err_typecheck_nonviable_condition)
3657 << false << From->getType() << From->getSourceRange() << ToType;
3658 }
3659
3660 CandidateSet.NoteCandidates(
3661 *this, From, Cands);
3662 return true;
3663 }
3664
3665 // Helper for compareConversionFunctions that gets the FunctionType that the
3666 // conversion-operator return value 'points' to, or nullptr.
3667 static const FunctionType *
getConversionOpReturnTyAsFunction(CXXConversionDecl * Conv)3668 getConversionOpReturnTyAsFunction(CXXConversionDecl *Conv) {
3669 const FunctionType *ConvFuncTy = Conv->getType()->castAs<FunctionType>();
3670 const PointerType *RetPtrTy =
3671 ConvFuncTy->getReturnType()->getAs<PointerType>();
3672
3673 if (!RetPtrTy)
3674 return nullptr;
3675
3676 return RetPtrTy->getPointeeType()->getAs<FunctionType>();
3677 }
3678
3679 /// Compare the user-defined conversion functions or constructors
3680 /// of two user-defined conversion sequences to determine whether any ordering
3681 /// is possible.
3682 static ImplicitConversionSequence::CompareKind
compareConversionFunctions(Sema & S,FunctionDecl * Function1,FunctionDecl * Function2)3683 compareConversionFunctions(Sema &S, FunctionDecl *Function1,
3684 FunctionDecl *Function2) {
3685 CXXConversionDecl *Conv1 = dyn_cast_or_null<CXXConversionDecl>(Function1);
3686 CXXConversionDecl *Conv2 = dyn_cast_or_null<CXXConversionDecl>(Function2);
3687 if (!Conv1 || !Conv2)
3688 return ImplicitConversionSequence::Indistinguishable;
3689
3690 if (!Conv1->getParent()->isLambda() || !Conv2->getParent()->isLambda())
3691 return ImplicitConversionSequence::Indistinguishable;
3692
3693 // Objective-C++:
3694 // If both conversion functions are implicitly-declared conversions from
3695 // a lambda closure type to a function pointer and a block pointer,
3696 // respectively, always prefer the conversion to a function pointer,
3697 // because the function pointer is more lightweight and is more likely
3698 // to keep code working.
3699 if (S.getLangOpts().ObjC && S.getLangOpts().CPlusPlus11) {
3700 bool Block1 = Conv1->getConversionType()->isBlockPointerType();
3701 bool Block2 = Conv2->getConversionType()->isBlockPointerType();
3702 if (Block1 != Block2)
3703 return Block1 ? ImplicitConversionSequence::Worse
3704 : ImplicitConversionSequence::Better;
3705 }
3706
3707 // In order to support multiple calling conventions for the lambda conversion
3708 // operator (such as when the free and member function calling convention is
3709 // different), prefer the 'free' mechanism, followed by the calling-convention
3710 // of operator(). The latter is in place to support the MSVC-like solution of
3711 // defining ALL of the possible conversions in regards to calling-convention.
3712 const FunctionType *Conv1FuncRet = getConversionOpReturnTyAsFunction(Conv1);
3713 const FunctionType *Conv2FuncRet = getConversionOpReturnTyAsFunction(Conv2);
3714
3715 if (Conv1FuncRet && Conv2FuncRet &&
3716 Conv1FuncRet->getCallConv() != Conv2FuncRet->getCallConv()) {
3717 CallingConv Conv1CC = Conv1FuncRet->getCallConv();
3718 CallingConv Conv2CC = Conv2FuncRet->getCallConv();
3719
3720 CXXMethodDecl *CallOp = Conv2->getParent()->getLambdaCallOperator();
3721 const FunctionProtoType *CallOpProto =
3722 CallOp->getType()->getAs<FunctionProtoType>();
3723
3724 CallingConv CallOpCC =
3725 CallOp->getType()->castAs<FunctionType>()->getCallConv();
3726 CallingConv DefaultFree = S.Context.getDefaultCallingConvention(
3727 CallOpProto->isVariadic(), /*IsCXXMethod=*/false);
3728 CallingConv DefaultMember = S.Context.getDefaultCallingConvention(
3729 CallOpProto->isVariadic(), /*IsCXXMethod=*/true);
3730
3731 CallingConv PrefOrder[] = {DefaultFree, DefaultMember, CallOpCC};
3732 for (CallingConv CC : PrefOrder) {
3733 if (Conv1CC == CC)
3734 return ImplicitConversionSequence::Better;
3735 if (Conv2CC == CC)
3736 return ImplicitConversionSequence::Worse;
3737 }
3738 }
3739
3740 return ImplicitConversionSequence::Indistinguishable;
3741 }
3742
hasDeprecatedStringLiteralToCharPtrConversion(const ImplicitConversionSequence & ICS)3743 static bool hasDeprecatedStringLiteralToCharPtrConversion(
3744 const ImplicitConversionSequence &ICS) {
3745 return (ICS.isStandard() && ICS.Standard.DeprecatedStringLiteralToCharPtr) ||
3746 (ICS.isUserDefined() &&
3747 ICS.UserDefined.Before.DeprecatedStringLiteralToCharPtr);
3748 }
3749
3750 /// CompareImplicitConversionSequences - Compare two implicit
3751 /// conversion sequences to determine whether one is better than the
3752 /// other or if they are indistinguishable (C++ 13.3.3.2).
3753 static ImplicitConversionSequence::CompareKind
CompareImplicitConversionSequences(Sema & S,SourceLocation Loc,const ImplicitConversionSequence & ICS1,const ImplicitConversionSequence & ICS2)3754 CompareImplicitConversionSequences(Sema &S, SourceLocation Loc,
3755 const ImplicitConversionSequence& ICS1,
3756 const ImplicitConversionSequence& ICS2)
3757 {
3758 // (C++ 13.3.3.2p2): When comparing the basic forms of implicit
3759 // conversion sequences (as defined in 13.3.3.1)
3760 // -- a standard conversion sequence (13.3.3.1.1) is a better
3761 // conversion sequence than a user-defined conversion sequence or
3762 // an ellipsis conversion sequence, and
3763 // -- a user-defined conversion sequence (13.3.3.1.2) is a better
3764 // conversion sequence than an ellipsis conversion sequence
3765 // (13.3.3.1.3).
3766 //
3767 // C++0x [over.best.ics]p10:
3768 // For the purpose of ranking implicit conversion sequences as
3769 // described in 13.3.3.2, the ambiguous conversion sequence is
3770 // treated as a user-defined sequence that is indistinguishable
3771 // from any other user-defined conversion sequence.
3772
3773 // String literal to 'char *' conversion has been deprecated in C++03. It has
3774 // been removed from C++11. We still accept this conversion, if it happens at
3775 // the best viable function. Otherwise, this conversion is considered worse
3776 // than ellipsis conversion. Consider this as an extension; this is not in the
3777 // standard. For example:
3778 //
3779 // int &f(...); // #1
3780 // void f(char*); // #2
3781 // void g() { int &r = f("foo"); }
3782 //
3783 // In C++03, we pick #2 as the best viable function.
3784 // In C++11, we pick #1 as the best viable function, because ellipsis
3785 // conversion is better than string-literal to char* conversion (since there
3786 // is no such conversion in C++11). If there was no #1 at all or #1 couldn't
3787 // convert arguments, #2 would be the best viable function in C++11.
3788 // If the best viable function has this conversion, a warning will be issued
3789 // in C++03, or an ExtWarn (+SFINAE failure) will be issued in C++11.
3790
3791 if (S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
3792 hasDeprecatedStringLiteralToCharPtrConversion(ICS1) !=
3793 hasDeprecatedStringLiteralToCharPtrConversion(ICS2) &&
3794 // Ill-formedness must not differ
3795 ICS1.isBad() == ICS2.isBad())
3796 return hasDeprecatedStringLiteralToCharPtrConversion(ICS1)
3797 ? ImplicitConversionSequence::Worse
3798 : ImplicitConversionSequence::Better;
3799
3800 if (ICS1.getKindRank() < ICS2.getKindRank())
3801 return ImplicitConversionSequence::Better;
3802 if (ICS2.getKindRank() < ICS1.getKindRank())
3803 return ImplicitConversionSequence::Worse;
3804
3805 // The following checks require both conversion sequences to be of
3806 // the same kind.
3807 if (ICS1.getKind() != ICS2.getKind())
3808 return ImplicitConversionSequence::Indistinguishable;
3809
3810 ImplicitConversionSequence::CompareKind Result =
3811 ImplicitConversionSequence::Indistinguishable;
3812
3813 // Two implicit conversion sequences of the same form are
3814 // indistinguishable conversion sequences unless one of the
3815 // following rules apply: (C++ 13.3.3.2p3):
3816
3817 // List-initialization sequence L1 is a better conversion sequence than
3818 // list-initialization sequence L2 if:
3819 // - L1 converts to std::initializer_list<X> for some X and L2 does not, or,
3820 // if not that,
3821 // — L1 and L2 convert to arrays of the same element type, and either the
3822 // number of elements n_1 initialized by L1 is less than the number of
3823 // elements n_2 initialized by L2, or (C++20) n_1 = n_2 and L2 converts to
3824 // an array of unknown bound and L1 does not,
3825 // even if one of the other rules in this paragraph would otherwise apply.
3826 if (!ICS1.isBad()) {
3827 bool StdInit1 = false, StdInit2 = false;
3828 if (ICS1.hasInitializerListContainerType())
3829 StdInit1 = S.isStdInitializerList(ICS1.getInitializerListContainerType(),
3830 nullptr);
3831 if (ICS2.hasInitializerListContainerType())
3832 StdInit2 = S.isStdInitializerList(ICS2.getInitializerListContainerType(),
3833 nullptr);
3834 if (StdInit1 != StdInit2)
3835 return StdInit1 ? ImplicitConversionSequence::Better
3836 : ImplicitConversionSequence::Worse;
3837
3838 if (ICS1.hasInitializerListContainerType() &&
3839 ICS2.hasInitializerListContainerType())
3840 if (auto *CAT1 = S.Context.getAsConstantArrayType(
3841 ICS1.getInitializerListContainerType()))
3842 if (auto *CAT2 = S.Context.getAsConstantArrayType(
3843 ICS2.getInitializerListContainerType())) {
3844 if (S.Context.hasSameUnqualifiedType(CAT1->getElementType(),
3845 CAT2->getElementType())) {
3846 // Both to arrays of the same element type
3847 if (CAT1->getSize() != CAT2->getSize())
3848 // Different sized, the smaller wins
3849 return CAT1->getSize().ult(CAT2->getSize())
3850 ? ImplicitConversionSequence::Better
3851 : ImplicitConversionSequence::Worse;
3852 if (ICS1.isInitializerListOfIncompleteArray() !=
3853 ICS2.isInitializerListOfIncompleteArray())
3854 // One is incomplete, it loses
3855 return ICS2.isInitializerListOfIncompleteArray()
3856 ? ImplicitConversionSequence::Better
3857 : ImplicitConversionSequence::Worse;
3858 }
3859 }
3860 }
3861
3862 if (ICS1.isStandard())
3863 // Standard conversion sequence S1 is a better conversion sequence than
3864 // standard conversion sequence S2 if [...]
3865 Result = CompareStandardConversionSequences(S, Loc,
3866 ICS1.Standard, ICS2.Standard);
3867 else if (ICS1.isUserDefined()) {
3868 // User-defined conversion sequence U1 is a better conversion
3869 // sequence than another user-defined conversion sequence U2 if
3870 // they contain the same user-defined conversion function or
3871 // constructor and if the second standard conversion sequence of
3872 // U1 is better than the second standard conversion sequence of
3873 // U2 (C++ 13.3.3.2p3).
3874 if (ICS1.UserDefined.ConversionFunction ==
3875 ICS2.UserDefined.ConversionFunction)
3876 Result = CompareStandardConversionSequences(S, Loc,
3877 ICS1.UserDefined.After,
3878 ICS2.UserDefined.After);
3879 else
3880 Result = compareConversionFunctions(S,
3881 ICS1.UserDefined.ConversionFunction,
3882 ICS2.UserDefined.ConversionFunction);
3883 }
3884
3885 return Result;
3886 }
3887
3888 // Per 13.3.3.2p3, compare the given standard conversion sequences to
3889 // determine if one is a proper subset of the other.
3890 static ImplicitConversionSequence::CompareKind
compareStandardConversionSubsets(ASTContext & Context,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3891 compareStandardConversionSubsets(ASTContext &Context,
3892 const StandardConversionSequence& SCS1,
3893 const StandardConversionSequence& SCS2) {
3894 ImplicitConversionSequence::CompareKind Result
3895 = ImplicitConversionSequence::Indistinguishable;
3896
3897 // the identity conversion sequence is considered to be a subsequence of
3898 // any non-identity conversion sequence
3899 if (SCS1.isIdentityConversion() && !SCS2.isIdentityConversion())
3900 return ImplicitConversionSequence::Better;
3901 else if (!SCS1.isIdentityConversion() && SCS2.isIdentityConversion())
3902 return ImplicitConversionSequence::Worse;
3903
3904 if (SCS1.Second != SCS2.Second) {
3905 if (SCS1.Second == ICK_Identity)
3906 Result = ImplicitConversionSequence::Better;
3907 else if (SCS2.Second == ICK_Identity)
3908 Result = ImplicitConversionSequence::Worse;
3909 else
3910 return ImplicitConversionSequence::Indistinguishable;
3911 } else if (!Context.hasSimilarType(SCS1.getToType(1), SCS2.getToType(1)))
3912 return ImplicitConversionSequence::Indistinguishable;
3913
3914 if (SCS1.Third == SCS2.Third) {
3915 return Context.hasSameType(SCS1.getToType(2), SCS2.getToType(2))? Result
3916 : ImplicitConversionSequence::Indistinguishable;
3917 }
3918
3919 if (SCS1.Third == ICK_Identity)
3920 return Result == ImplicitConversionSequence::Worse
3921 ? ImplicitConversionSequence::Indistinguishable
3922 : ImplicitConversionSequence::Better;
3923
3924 if (SCS2.Third == ICK_Identity)
3925 return Result == ImplicitConversionSequence::Better
3926 ? ImplicitConversionSequence::Indistinguishable
3927 : ImplicitConversionSequence::Worse;
3928
3929 return ImplicitConversionSequence::Indistinguishable;
3930 }
3931
3932 /// Determine whether one of the given reference bindings is better
3933 /// than the other based on what kind of bindings they are.
3934 static bool
isBetterReferenceBindingKind(const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3935 isBetterReferenceBindingKind(const StandardConversionSequence &SCS1,
3936 const StandardConversionSequence &SCS2) {
3937 // C++0x [over.ics.rank]p3b4:
3938 // -- S1 and S2 are reference bindings (8.5.3) and neither refers to an
3939 // implicit object parameter of a non-static member function declared
3940 // without a ref-qualifier, and *either* S1 binds an rvalue reference
3941 // to an rvalue and S2 binds an lvalue reference *or S1 binds an
3942 // lvalue reference to a function lvalue and S2 binds an rvalue
3943 // reference*.
3944 //
3945 // FIXME: Rvalue references. We're going rogue with the above edits,
3946 // because the semantics in the current C++0x working paper (N3225 at the
3947 // time of this writing) break the standard definition of std::forward
3948 // and std::reference_wrapper when dealing with references to functions.
3949 // Proposed wording changes submitted to CWG for consideration.
3950 if (SCS1.BindsImplicitObjectArgumentWithoutRefQualifier ||
3951 SCS2.BindsImplicitObjectArgumentWithoutRefQualifier)
3952 return false;
3953
3954 return (!SCS1.IsLvalueReference && SCS1.BindsToRvalue &&
3955 SCS2.IsLvalueReference) ||
3956 (SCS1.IsLvalueReference && SCS1.BindsToFunctionLvalue &&
3957 !SCS2.IsLvalueReference && SCS2.BindsToFunctionLvalue);
3958 }
3959
3960 enum class FixedEnumPromotion {
3961 None,
3962 ToUnderlyingType,
3963 ToPromotedUnderlyingType
3964 };
3965
3966 /// Returns kind of fixed enum promotion the \a SCS uses.
3967 static FixedEnumPromotion
getFixedEnumPromtion(Sema & S,const StandardConversionSequence & SCS)3968 getFixedEnumPromtion(Sema &S, const StandardConversionSequence &SCS) {
3969
3970 if (SCS.Second != ICK_Integral_Promotion)
3971 return FixedEnumPromotion::None;
3972
3973 QualType FromType = SCS.getFromType();
3974 if (!FromType->isEnumeralType())
3975 return FixedEnumPromotion::None;
3976
3977 EnumDecl *Enum = FromType->castAs<EnumType>()->getDecl();
3978 if (!Enum->isFixed())
3979 return FixedEnumPromotion::None;
3980
3981 QualType UnderlyingType = Enum->getIntegerType();
3982 if (S.Context.hasSameType(SCS.getToType(1), UnderlyingType))
3983 return FixedEnumPromotion::ToUnderlyingType;
3984
3985 return FixedEnumPromotion::ToPromotedUnderlyingType;
3986 }
3987
3988 /// CompareStandardConversionSequences - Compare two standard
3989 /// conversion sequences to determine whether one is better than the
3990 /// other or if they are indistinguishable (C++ 13.3.3.2p3).
3991 static ImplicitConversionSequence::CompareKind
CompareStandardConversionSequences(Sema & S,SourceLocation Loc,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)3992 CompareStandardConversionSequences(Sema &S, SourceLocation Loc,
3993 const StandardConversionSequence& SCS1,
3994 const StandardConversionSequence& SCS2)
3995 {
3996 // Standard conversion sequence S1 is a better conversion sequence
3997 // than standard conversion sequence S2 if (C++ 13.3.3.2p3):
3998
3999 // -- S1 is a proper subsequence of S2 (comparing the conversion
4000 // sequences in the canonical form defined by 13.3.3.1.1,
4001 // excluding any Lvalue Transformation; the identity conversion
4002 // sequence is considered to be a subsequence of any
4003 // non-identity conversion sequence) or, if not that,
4004 if (ImplicitConversionSequence::CompareKind CK
4005 = compareStandardConversionSubsets(S.Context, SCS1, SCS2))
4006 return CK;
4007
4008 // -- the rank of S1 is better than the rank of S2 (by the rules
4009 // defined below), or, if not that,
4010 ImplicitConversionRank Rank1 = SCS1.getRank();
4011 ImplicitConversionRank Rank2 = SCS2.getRank();
4012 if (Rank1 < Rank2)
4013 return ImplicitConversionSequence::Better;
4014 else if (Rank2 < Rank1)
4015 return ImplicitConversionSequence::Worse;
4016
4017 // (C++ 13.3.3.2p4): Two conversion sequences with the same rank
4018 // are indistinguishable unless one of the following rules
4019 // applies:
4020
4021 // A conversion that is not a conversion of a pointer, or
4022 // pointer to member, to bool is better than another conversion
4023 // that is such a conversion.
4024 if (SCS1.isPointerConversionToBool() != SCS2.isPointerConversionToBool())
4025 return SCS2.isPointerConversionToBool()
4026 ? ImplicitConversionSequence::Better
4027 : ImplicitConversionSequence::Worse;
4028
4029 // C++14 [over.ics.rank]p4b2:
4030 // This is retroactively applied to C++11 by CWG 1601.
4031 //
4032 // A conversion that promotes an enumeration whose underlying type is fixed
4033 // to its underlying type is better than one that promotes to the promoted
4034 // underlying type, if the two are different.
4035 FixedEnumPromotion FEP1 = getFixedEnumPromtion(S, SCS1);
4036 FixedEnumPromotion FEP2 = getFixedEnumPromtion(S, SCS2);
4037 if (FEP1 != FixedEnumPromotion::None && FEP2 != FixedEnumPromotion::None &&
4038 FEP1 != FEP2)
4039 return FEP1 == FixedEnumPromotion::ToUnderlyingType
4040 ? ImplicitConversionSequence::Better
4041 : ImplicitConversionSequence::Worse;
4042
4043 // C++ [over.ics.rank]p4b2:
4044 //
4045 // If class B is derived directly or indirectly from class A,
4046 // conversion of B* to A* is better than conversion of B* to
4047 // void*, and conversion of A* to void* is better than conversion
4048 // of B* to void*.
4049 bool SCS1ConvertsToVoid
4050 = SCS1.isPointerConversionToVoidPointer(S.Context);
4051 bool SCS2ConvertsToVoid
4052 = SCS2.isPointerConversionToVoidPointer(S.Context);
4053 if (SCS1ConvertsToVoid != SCS2ConvertsToVoid) {
4054 // Exactly one of the conversion sequences is a conversion to
4055 // a void pointer; it's the worse conversion.
4056 return SCS2ConvertsToVoid ? ImplicitConversionSequence::Better
4057 : ImplicitConversionSequence::Worse;
4058 } else if (!SCS1ConvertsToVoid && !SCS2ConvertsToVoid) {
4059 // Neither conversion sequence converts to a void pointer; compare
4060 // their derived-to-base conversions.
4061 if (ImplicitConversionSequence::CompareKind DerivedCK
4062 = CompareDerivedToBaseConversions(S, Loc, SCS1, SCS2))
4063 return DerivedCK;
4064 } else if (SCS1ConvertsToVoid && SCS2ConvertsToVoid &&
4065 !S.Context.hasSameType(SCS1.getFromType(), SCS2.getFromType())) {
4066 // Both conversion sequences are conversions to void
4067 // pointers. Compare the source types to determine if there's an
4068 // inheritance relationship in their sources.
4069 QualType FromType1 = SCS1.getFromType();
4070 QualType FromType2 = SCS2.getFromType();
4071
4072 // Adjust the types we're converting from via the array-to-pointer
4073 // conversion, if we need to.
4074 if (SCS1.First == ICK_Array_To_Pointer)
4075 FromType1 = S.Context.getArrayDecayedType(FromType1);
4076 if (SCS2.First == ICK_Array_To_Pointer)
4077 FromType2 = S.Context.getArrayDecayedType(FromType2);
4078
4079 QualType FromPointee1 = FromType1->getPointeeType().getUnqualifiedType();
4080 QualType FromPointee2 = FromType2->getPointeeType().getUnqualifiedType();
4081
4082 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4083 return ImplicitConversionSequence::Better;
4084 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4085 return ImplicitConversionSequence::Worse;
4086
4087 // Objective-C++: If one interface is more specific than the
4088 // other, it is the better one.
4089 const ObjCObjectPointerType* FromObjCPtr1
4090 = FromType1->getAs<ObjCObjectPointerType>();
4091 const ObjCObjectPointerType* FromObjCPtr2
4092 = FromType2->getAs<ObjCObjectPointerType>();
4093 if (FromObjCPtr1 && FromObjCPtr2) {
4094 bool AssignLeft = S.Context.canAssignObjCInterfaces(FromObjCPtr1,
4095 FromObjCPtr2);
4096 bool AssignRight = S.Context.canAssignObjCInterfaces(FromObjCPtr2,
4097 FromObjCPtr1);
4098 if (AssignLeft != AssignRight) {
4099 return AssignLeft? ImplicitConversionSequence::Better
4100 : ImplicitConversionSequence::Worse;
4101 }
4102 }
4103 }
4104
4105 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4106 // Check for a better reference binding based on the kind of bindings.
4107 if (isBetterReferenceBindingKind(SCS1, SCS2))
4108 return ImplicitConversionSequence::Better;
4109 else if (isBetterReferenceBindingKind(SCS2, SCS1))
4110 return ImplicitConversionSequence::Worse;
4111 }
4112
4113 // Compare based on qualification conversions (C++ 13.3.3.2p3,
4114 // bullet 3).
4115 if (ImplicitConversionSequence::CompareKind QualCK
4116 = CompareQualificationConversions(S, SCS1, SCS2))
4117 return QualCK;
4118
4119 if (SCS1.ReferenceBinding && SCS2.ReferenceBinding) {
4120 // C++ [over.ics.rank]p3b4:
4121 // -- S1 and S2 are reference bindings (8.5.3), and the types to
4122 // which the references refer are the same type except for
4123 // top-level cv-qualifiers, and the type to which the reference
4124 // initialized by S2 refers is more cv-qualified than the type
4125 // to which the reference initialized by S1 refers.
4126 QualType T1 = SCS1.getToType(2);
4127 QualType T2 = SCS2.getToType(2);
4128 T1 = S.Context.getCanonicalType(T1);
4129 T2 = S.Context.getCanonicalType(T2);
4130 Qualifiers T1Quals, T2Quals;
4131 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4132 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4133 if (UnqualT1 == UnqualT2) {
4134 // Objective-C++ ARC: If the references refer to objects with different
4135 // lifetimes, prefer bindings that don't change lifetime.
4136 if (SCS1.ObjCLifetimeConversionBinding !=
4137 SCS2.ObjCLifetimeConversionBinding) {
4138 return SCS1.ObjCLifetimeConversionBinding
4139 ? ImplicitConversionSequence::Worse
4140 : ImplicitConversionSequence::Better;
4141 }
4142
4143 // If the type is an array type, promote the element qualifiers to the
4144 // type for comparison.
4145 if (isa<ArrayType>(T1) && T1Quals)
4146 T1 = S.Context.getQualifiedType(UnqualT1, T1Quals);
4147 if (isa<ArrayType>(T2) && T2Quals)
4148 T2 = S.Context.getQualifiedType(UnqualT2, T2Quals);
4149 if (T2.isMoreQualifiedThan(T1))
4150 return ImplicitConversionSequence::Better;
4151 if (T1.isMoreQualifiedThan(T2))
4152 return ImplicitConversionSequence::Worse;
4153 }
4154 }
4155
4156 // In Microsoft mode (below 19.28), prefer an integral conversion to a
4157 // floating-to-integral conversion if the integral conversion
4158 // is between types of the same size.
4159 // For example:
4160 // void f(float);
4161 // void f(int);
4162 // int main {
4163 // long a;
4164 // f(a);
4165 // }
4166 // Here, MSVC will call f(int) instead of generating a compile error
4167 // as clang will do in standard mode.
4168 if (S.getLangOpts().MSVCCompat &&
4169 !S.getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2019_8) &&
4170 SCS1.Second == ICK_Integral_Conversion &&
4171 SCS2.Second == ICK_Floating_Integral &&
4172 S.Context.getTypeSize(SCS1.getFromType()) ==
4173 S.Context.getTypeSize(SCS1.getToType(2)))
4174 return ImplicitConversionSequence::Better;
4175
4176 // Prefer a compatible vector conversion over a lax vector conversion
4177 // For example:
4178 //
4179 // typedef float __v4sf __attribute__((__vector_size__(16)));
4180 // void f(vector float);
4181 // void f(vector signed int);
4182 // int main() {
4183 // __v4sf a;
4184 // f(a);
4185 // }
4186 // Here, we'd like to choose f(vector float) and not
4187 // report an ambiguous call error
4188 if (SCS1.Second == ICK_Vector_Conversion &&
4189 SCS2.Second == ICK_Vector_Conversion) {
4190 bool SCS1IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4191 SCS1.getFromType(), SCS1.getToType(2));
4192 bool SCS2IsCompatibleVectorConversion = S.Context.areCompatibleVectorTypes(
4193 SCS2.getFromType(), SCS2.getToType(2));
4194
4195 if (SCS1IsCompatibleVectorConversion != SCS2IsCompatibleVectorConversion)
4196 return SCS1IsCompatibleVectorConversion
4197 ? ImplicitConversionSequence::Better
4198 : ImplicitConversionSequence::Worse;
4199 }
4200
4201 if (SCS1.Second == ICK_SVE_Vector_Conversion &&
4202 SCS2.Second == ICK_SVE_Vector_Conversion) {
4203 bool SCS1IsCompatibleSVEVectorConversion =
4204 S.Context.areCompatibleSveTypes(SCS1.getFromType(), SCS1.getToType(2));
4205 bool SCS2IsCompatibleSVEVectorConversion =
4206 S.Context.areCompatibleSveTypes(SCS2.getFromType(), SCS2.getToType(2));
4207
4208 if (SCS1IsCompatibleSVEVectorConversion !=
4209 SCS2IsCompatibleSVEVectorConversion)
4210 return SCS1IsCompatibleSVEVectorConversion
4211 ? ImplicitConversionSequence::Better
4212 : ImplicitConversionSequence::Worse;
4213 }
4214
4215 return ImplicitConversionSequence::Indistinguishable;
4216 }
4217
4218 /// CompareQualificationConversions - Compares two standard conversion
4219 /// sequences to determine whether they can be ranked based on their
4220 /// qualification conversions (C++ 13.3.3.2p3 bullet 3).
4221 static ImplicitConversionSequence::CompareKind
CompareQualificationConversions(Sema & S,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)4222 CompareQualificationConversions(Sema &S,
4223 const StandardConversionSequence& SCS1,
4224 const StandardConversionSequence& SCS2) {
4225 // C++ [over.ics.rank]p3:
4226 // -- S1 and S2 differ only in their qualification conversion and
4227 // yield similar types T1 and T2 (C++ 4.4), respectively, [...]
4228 // [C++98]
4229 // [...] and the cv-qualification signature of type T1 is a proper subset
4230 // of the cv-qualification signature of type T2, and S1 is not the
4231 // deprecated string literal array-to-pointer conversion (4.2).
4232 // [C++2a]
4233 // [...] where T1 can be converted to T2 by a qualification conversion.
4234 if (SCS1.First != SCS2.First || SCS1.Second != SCS2.Second ||
4235 SCS1.Third != SCS2.Third || SCS1.Third != ICK_Qualification)
4236 return ImplicitConversionSequence::Indistinguishable;
4237
4238 // FIXME: the example in the standard doesn't use a qualification
4239 // conversion (!)
4240 QualType T1 = SCS1.getToType(2);
4241 QualType T2 = SCS2.getToType(2);
4242 T1 = S.Context.getCanonicalType(T1);
4243 T2 = S.Context.getCanonicalType(T2);
4244 assert(!T1->isReferenceType() && !T2->isReferenceType());
4245 Qualifiers T1Quals, T2Quals;
4246 QualType UnqualT1 = S.Context.getUnqualifiedArrayType(T1, T1Quals);
4247 QualType UnqualT2 = S.Context.getUnqualifiedArrayType(T2, T2Quals);
4248
4249 // If the types are the same, we won't learn anything by unwrapping
4250 // them.
4251 if (UnqualT1 == UnqualT2)
4252 return ImplicitConversionSequence::Indistinguishable;
4253
4254 // Don't ever prefer a standard conversion sequence that uses the deprecated
4255 // string literal array to pointer conversion.
4256 bool CanPick1 = !SCS1.DeprecatedStringLiteralToCharPtr;
4257 bool CanPick2 = !SCS2.DeprecatedStringLiteralToCharPtr;
4258
4259 // Objective-C++ ARC:
4260 // Prefer qualification conversions not involving a change in lifetime
4261 // to qualification conversions that do change lifetime.
4262 if (SCS1.QualificationIncludesObjCLifetime &&
4263 !SCS2.QualificationIncludesObjCLifetime)
4264 CanPick1 = false;
4265 if (SCS2.QualificationIncludesObjCLifetime &&
4266 !SCS1.QualificationIncludesObjCLifetime)
4267 CanPick2 = false;
4268
4269 bool ObjCLifetimeConversion;
4270 if (CanPick1 &&
4271 !S.IsQualificationConversion(T1, T2, false, ObjCLifetimeConversion))
4272 CanPick1 = false;
4273 // FIXME: In Objective-C ARC, we can have qualification conversions in both
4274 // directions, so we can't short-cut this second check in general.
4275 if (CanPick2 &&
4276 !S.IsQualificationConversion(T2, T1, false, ObjCLifetimeConversion))
4277 CanPick2 = false;
4278
4279 if (CanPick1 != CanPick2)
4280 return CanPick1 ? ImplicitConversionSequence::Better
4281 : ImplicitConversionSequence::Worse;
4282 return ImplicitConversionSequence::Indistinguishable;
4283 }
4284
4285 /// CompareDerivedToBaseConversions - Compares two standard conversion
4286 /// sequences to determine whether they can be ranked based on their
4287 /// various kinds of derived-to-base conversions (C++
4288 /// [over.ics.rank]p4b3). As part of these checks, we also look at
4289 /// conversions between Objective-C interface types.
4290 static ImplicitConversionSequence::CompareKind
CompareDerivedToBaseConversions(Sema & S,SourceLocation Loc,const StandardConversionSequence & SCS1,const StandardConversionSequence & SCS2)4291 CompareDerivedToBaseConversions(Sema &S, SourceLocation Loc,
4292 const StandardConversionSequence& SCS1,
4293 const StandardConversionSequence& SCS2) {
4294 QualType FromType1 = SCS1.getFromType();
4295 QualType ToType1 = SCS1.getToType(1);
4296 QualType FromType2 = SCS2.getFromType();
4297 QualType ToType2 = SCS2.getToType(1);
4298
4299 // Adjust the types we're converting from via the array-to-pointer
4300 // conversion, if we need to.
4301 if (SCS1.First == ICK_Array_To_Pointer)
4302 FromType1 = S.Context.getArrayDecayedType(FromType1);
4303 if (SCS2.First == ICK_Array_To_Pointer)
4304 FromType2 = S.Context.getArrayDecayedType(FromType2);
4305
4306 // Canonicalize all of the types.
4307 FromType1 = S.Context.getCanonicalType(FromType1);
4308 ToType1 = S.Context.getCanonicalType(ToType1);
4309 FromType2 = S.Context.getCanonicalType(FromType2);
4310 ToType2 = S.Context.getCanonicalType(ToType2);
4311
4312 // C++ [over.ics.rank]p4b3:
4313 //
4314 // If class B is derived directly or indirectly from class A and
4315 // class C is derived directly or indirectly from B,
4316 //
4317 // Compare based on pointer conversions.
4318 if (SCS1.Second == ICK_Pointer_Conversion &&
4319 SCS2.Second == ICK_Pointer_Conversion &&
4320 /*FIXME: Remove if Objective-C id conversions get their own rank*/
4321 FromType1->isPointerType() && FromType2->isPointerType() &&
4322 ToType1->isPointerType() && ToType2->isPointerType()) {
4323 QualType FromPointee1 =
4324 FromType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4325 QualType ToPointee1 =
4326 ToType1->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4327 QualType FromPointee2 =
4328 FromType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4329 QualType ToPointee2 =
4330 ToType2->castAs<PointerType>()->getPointeeType().getUnqualifiedType();
4331
4332 // -- conversion of C* to B* is better than conversion of C* to A*,
4333 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4334 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4335 return ImplicitConversionSequence::Better;
4336 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4337 return ImplicitConversionSequence::Worse;
4338 }
4339
4340 // -- conversion of B* to A* is better than conversion of C* to A*,
4341 if (FromPointee1 != FromPointee2 && ToPointee1 == ToPointee2) {
4342 if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4343 return ImplicitConversionSequence::Better;
4344 else if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4345 return ImplicitConversionSequence::Worse;
4346 }
4347 } else if (SCS1.Second == ICK_Pointer_Conversion &&
4348 SCS2.Second == ICK_Pointer_Conversion) {
4349 const ObjCObjectPointerType *FromPtr1
4350 = FromType1->getAs<ObjCObjectPointerType>();
4351 const ObjCObjectPointerType *FromPtr2
4352 = FromType2->getAs<ObjCObjectPointerType>();
4353 const ObjCObjectPointerType *ToPtr1
4354 = ToType1->getAs<ObjCObjectPointerType>();
4355 const ObjCObjectPointerType *ToPtr2
4356 = ToType2->getAs<ObjCObjectPointerType>();
4357
4358 if (FromPtr1 && FromPtr2 && ToPtr1 && ToPtr2) {
4359 // Apply the same conversion ranking rules for Objective-C pointer types
4360 // that we do for C++ pointers to class types. However, we employ the
4361 // Objective-C pseudo-subtyping relationship used for assignment of
4362 // Objective-C pointer types.
4363 bool FromAssignLeft
4364 = S.Context.canAssignObjCInterfaces(FromPtr1, FromPtr2);
4365 bool FromAssignRight
4366 = S.Context.canAssignObjCInterfaces(FromPtr2, FromPtr1);
4367 bool ToAssignLeft
4368 = S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
4369 bool ToAssignRight
4370 = S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
4371
4372 // A conversion to an a non-id object pointer type or qualified 'id'
4373 // type is better than a conversion to 'id'.
4374 if (ToPtr1->isObjCIdType() &&
4375 (ToPtr2->isObjCQualifiedIdType() || ToPtr2->getInterfaceDecl()))
4376 return ImplicitConversionSequence::Worse;
4377 if (ToPtr2->isObjCIdType() &&
4378 (ToPtr1->isObjCQualifiedIdType() || ToPtr1->getInterfaceDecl()))
4379 return ImplicitConversionSequence::Better;
4380
4381 // A conversion to a non-id object pointer type is better than a
4382 // conversion to a qualified 'id' type
4383 if (ToPtr1->isObjCQualifiedIdType() && ToPtr2->getInterfaceDecl())
4384 return ImplicitConversionSequence::Worse;
4385 if (ToPtr2->isObjCQualifiedIdType() && ToPtr1->getInterfaceDecl())
4386 return ImplicitConversionSequence::Better;
4387
4388 // A conversion to an a non-Class object pointer type or qualified 'Class'
4389 // type is better than a conversion to 'Class'.
4390 if (ToPtr1->isObjCClassType() &&
4391 (ToPtr2->isObjCQualifiedClassType() || ToPtr2->getInterfaceDecl()))
4392 return ImplicitConversionSequence::Worse;
4393 if (ToPtr2->isObjCClassType() &&
4394 (ToPtr1->isObjCQualifiedClassType() || ToPtr1->getInterfaceDecl()))
4395 return ImplicitConversionSequence::Better;
4396
4397 // A conversion to a non-Class object pointer type is better than a
4398 // conversion to a qualified 'Class' type.
4399 if (ToPtr1->isObjCQualifiedClassType() && ToPtr2->getInterfaceDecl())
4400 return ImplicitConversionSequence::Worse;
4401 if (ToPtr2->isObjCQualifiedClassType() && ToPtr1->getInterfaceDecl())
4402 return ImplicitConversionSequence::Better;
4403
4404 // -- "conversion of C* to B* is better than conversion of C* to A*,"
4405 if (S.Context.hasSameType(FromType1, FromType2) &&
4406 !FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
4407 (ToAssignLeft != ToAssignRight)) {
4408 if (FromPtr1->isSpecialized()) {
4409 // "conversion of B<A> * to B * is better than conversion of B * to
4410 // C *.
4411 bool IsFirstSame =
4412 FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
4413 bool IsSecondSame =
4414 FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
4415 if (IsFirstSame) {
4416 if (!IsSecondSame)
4417 return ImplicitConversionSequence::Better;
4418 } else if (IsSecondSame)
4419 return ImplicitConversionSequence::Worse;
4420 }
4421 return ToAssignLeft? ImplicitConversionSequence::Worse
4422 : ImplicitConversionSequence::Better;
4423 }
4424
4425 // -- "conversion of B* to A* is better than conversion of C* to A*,"
4426 if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&
4427 (FromAssignLeft != FromAssignRight))
4428 return FromAssignLeft? ImplicitConversionSequence::Better
4429 : ImplicitConversionSequence::Worse;
4430 }
4431 }
4432
4433 // Ranking of member-pointer types.
4434 if (SCS1.Second == ICK_Pointer_Member && SCS2.Second == ICK_Pointer_Member &&
4435 FromType1->isMemberPointerType() && FromType2->isMemberPointerType() &&
4436 ToType1->isMemberPointerType() && ToType2->isMemberPointerType()) {
4437 const auto *FromMemPointer1 = FromType1->castAs<MemberPointerType>();
4438 const auto *ToMemPointer1 = ToType1->castAs<MemberPointerType>();
4439 const auto *FromMemPointer2 = FromType2->castAs<MemberPointerType>();
4440 const auto *ToMemPointer2 = ToType2->castAs<MemberPointerType>();
4441 const Type *FromPointeeType1 = FromMemPointer1->getClass();
4442 const Type *ToPointeeType1 = ToMemPointer1->getClass();
4443 const Type *FromPointeeType2 = FromMemPointer2->getClass();
4444 const Type *ToPointeeType2 = ToMemPointer2->getClass();
4445 QualType FromPointee1 = QualType(FromPointeeType1, 0).getUnqualifiedType();
4446 QualType ToPointee1 = QualType(ToPointeeType1, 0).getUnqualifiedType();
4447 QualType FromPointee2 = QualType(FromPointeeType2, 0).getUnqualifiedType();
4448 QualType ToPointee2 = QualType(ToPointeeType2, 0).getUnqualifiedType();
4449 // conversion of A::* to B::* is better than conversion of A::* to C::*,
4450 if (FromPointee1 == FromPointee2 && ToPointee1 != ToPointee2) {
4451 if (S.IsDerivedFrom(Loc, ToPointee1, ToPointee2))
4452 return ImplicitConversionSequence::Worse;
4453 else if (S.IsDerivedFrom(Loc, ToPointee2, ToPointee1))
4454 return ImplicitConversionSequence::Better;
4455 }
4456 // conversion of B::* to C::* is better than conversion of A::* to C::*
4457 if (ToPointee1 == ToPointee2 && FromPointee1 != FromPointee2) {
4458 if (S.IsDerivedFrom(Loc, FromPointee1, FromPointee2))
4459 return ImplicitConversionSequence::Better;
4460 else if (S.IsDerivedFrom(Loc, FromPointee2, FromPointee1))
4461 return ImplicitConversionSequence::Worse;
4462 }
4463 }
4464
4465 if (SCS1.Second == ICK_Derived_To_Base) {
4466 // -- conversion of C to B is better than conversion of C to A,
4467 // -- binding of an expression of type C to a reference of type
4468 // B& is better than binding an expression of type C to a
4469 // reference of type A&,
4470 if (S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4471 !S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4472 if (S.IsDerivedFrom(Loc, ToType1, ToType2))
4473 return ImplicitConversionSequence::Better;
4474 else if (S.IsDerivedFrom(Loc, ToType2, ToType1))
4475 return ImplicitConversionSequence::Worse;
4476 }
4477
4478 // -- conversion of B to A is better than conversion of C to A.
4479 // -- binding of an expression of type B to a reference of type
4480 // A& is better than binding an expression of type C to a
4481 // reference of type A&,
4482 if (!S.Context.hasSameUnqualifiedType(FromType1, FromType2) &&
4483 S.Context.hasSameUnqualifiedType(ToType1, ToType2)) {
4484 if (S.IsDerivedFrom(Loc, FromType2, FromType1))
4485 return ImplicitConversionSequence::Better;
4486 else if (S.IsDerivedFrom(Loc, FromType1, FromType2))
4487 return ImplicitConversionSequence::Worse;
4488 }
4489 }
4490
4491 return ImplicitConversionSequence::Indistinguishable;
4492 }
4493
4494 /// Determine whether the given type is valid, e.g., it is not an invalid
4495 /// C++ class.
isTypeValid(QualType T)4496 static bool isTypeValid(QualType T) {
4497 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl())
4498 return !Record->isInvalidDecl();
4499
4500 return true;
4501 }
4502
withoutUnaligned(ASTContext & Ctx,QualType T)4503 static QualType withoutUnaligned(ASTContext &Ctx, QualType T) {
4504 if (!T.getQualifiers().hasUnaligned())
4505 return T;
4506
4507 Qualifiers Q;
4508 T = Ctx.getUnqualifiedArrayType(T, Q);
4509 Q.removeUnaligned();
4510 return Ctx.getQualifiedType(T, Q);
4511 }
4512
4513 /// CompareReferenceRelationship - Compare the two types T1 and T2 to
4514 /// determine whether they are reference-compatible,
4515 /// reference-related, or incompatible, for use in C++ initialization by
4516 /// reference (C++ [dcl.ref.init]p4). Neither type can be a reference
4517 /// type, and the first type (T1) is the pointee type of the reference
4518 /// type being initialized.
4519 Sema::ReferenceCompareResult
CompareReferenceRelationship(SourceLocation Loc,QualType OrigT1,QualType OrigT2,ReferenceConversions * ConvOut)4520 Sema::CompareReferenceRelationship(SourceLocation Loc,
4521 QualType OrigT1, QualType OrigT2,
4522 ReferenceConversions *ConvOut) {
4523 assert(!OrigT1->isReferenceType() &&
4524 "T1 must be the pointee type of the reference type");
4525 assert(!OrigT2->isReferenceType() && "T2 cannot be a reference type");
4526
4527 QualType T1 = Context.getCanonicalType(OrigT1);
4528 QualType T2 = Context.getCanonicalType(OrigT2);
4529 Qualifiers T1Quals, T2Quals;
4530 QualType UnqualT1 = Context.getUnqualifiedArrayType(T1, T1Quals);
4531 QualType UnqualT2 = Context.getUnqualifiedArrayType(T2, T2Quals);
4532
4533 ReferenceConversions ConvTmp;
4534 ReferenceConversions &Conv = ConvOut ? *ConvOut : ConvTmp;
4535 Conv = ReferenceConversions();
4536
4537 // C++2a [dcl.init.ref]p4:
4538 // Given types "cv1 T1" and "cv2 T2," "cv1 T1" is
4539 // reference-related to "cv2 T2" if T1 is similar to T2, or
4540 // T1 is a base class of T2.
4541 // "cv1 T1" is reference-compatible with "cv2 T2" if
4542 // a prvalue of type "pointer to cv2 T2" can be converted to the type
4543 // "pointer to cv1 T1" via a standard conversion sequence.
4544
4545 // Check for standard conversions we can apply to pointers: derived-to-base
4546 // conversions, ObjC pointer conversions, and function pointer conversions.
4547 // (Qualification conversions are checked last.)
4548 QualType ConvertedT2;
4549 if (UnqualT1 == UnqualT2) {
4550 // Nothing to do.
4551 } else if (isCompleteType(Loc, OrigT2) &&
4552 isTypeValid(UnqualT1) && isTypeValid(UnqualT2) &&
4553 IsDerivedFrom(Loc, UnqualT2, UnqualT1))
4554 Conv |= ReferenceConversions::DerivedToBase;
4555 else if (UnqualT1->isObjCObjectOrInterfaceType() &&
4556 UnqualT2->isObjCObjectOrInterfaceType() &&
4557 Context.canBindObjCObjectType(UnqualT1, UnqualT2))
4558 Conv |= ReferenceConversions::ObjC;
4559 else if (UnqualT2->isFunctionType() &&
4560 IsFunctionConversion(UnqualT2, UnqualT1, ConvertedT2)) {
4561 Conv |= ReferenceConversions::Function;
4562 // No need to check qualifiers; function types don't have them.
4563 return Ref_Compatible;
4564 }
4565 bool ConvertedReferent = Conv != 0;
4566
4567 // We can have a qualification conversion. Compute whether the types are
4568 // similar at the same time.
4569 bool PreviousToQualsIncludeConst = true;
4570 bool TopLevel = true;
4571 do {
4572 if (T1 == T2)
4573 break;
4574
4575 // We will need a qualification conversion.
4576 Conv |= ReferenceConversions::Qualification;
4577
4578 // Track whether we performed a qualification conversion anywhere other
4579 // than the top level. This matters for ranking reference bindings in
4580 // overload resolution.
4581 if (!TopLevel)
4582 Conv |= ReferenceConversions::NestedQualification;
4583
4584 // MS compiler ignores __unaligned qualifier for references; do the same.
4585 T1 = withoutUnaligned(Context, T1);
4586 T2 = withoutUnaligned(Context, T2);
4587
4588 // If we find a qualifier mismatch, the types are not reference-compatible,
4589 // but are still be reference-related if they're similar.
4590 bool ObjCLifetimeConversion = false;
4591 if (!isQualificationConversionStep(T2, T1, /*CStyle=*/false, TopLevel,
4592 PreviousToQualsIncludeConst,
4593 ObjCLifetimeConversion))
4594 return (ConvertedReferent || Context.hasSimilarType(T1, T2))
4595 ? Ref_Related
4596 : Ref_Incompatible;
4597
4598 // FIXME: Should we track this for any level other than the first?
4599 if (ObjCLifetimeConversion)
4600 Conv |= ReferenceConversions::ObjCLifetime;
4601
4602 TopLevel = false;
4603 } while (Context.UnwrapSimilarTypes(T1, T2));
4604
4605 // At this point, if the types are reference-related, we must either have the
4606 // same inner type (ignoring qualifiers), or must have already worked out how
4607 // to convert the referent.
4608 return (ConvertedReferent || Context.hasSameUnqualifiedType(T1, T2))
4609 ? Ref_Compatible
4610 : Ref_Incompatible;
4611 }
4612
4613 /// Look for a user-defined conversion to a value reference-compatible
4614 /// with DeclType. Return true if something definite is found.
4615 static bool
FindConversionForRefInit(Sema & S,ImplicitConversionSequence & ICS,QualType DeclType,SourceLocation DeclLoc,Expr * Init,QualType T2,bool AllowRvalues,bool AllowExplicit)4616 FindConversionForRefInit(Sema &S, ImplicitConversionSequence &ICS,
4617 QualType DeclType, SourceLocation DeclLoc,
4618 Expr *Init, QualType T2, bool AllowRvalues,
4619 bool AllowExplicit) {
4620 assert(T2->isRecordType() && "Can only find conversions of record types.");
4621 auto *T2RecordDecl = cast<CXXRecordDecl>(T2->castAs<RecordType>()->getDecl());
4622
4623 OverloadCandidateSet CandidateSet(
4624 DeclLoc, OverloadCandidateSet::CSK_InitByUserDefinedConversion);
4625 const auto &Conversions = T2RecordDecl->getVisibleConversionFunctions();
4626 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
4627 NamedDecl *D = *I;
4628 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(D->getDeclContext());
4629 if (isa<UsingShadowDecl>(D))
4630 D = cast<UsingShadowDecl>(D)->getTargetDecl();
4631
4632 FunctionTemplateDecl *ConvTemplate
4633 = dyn_cast<FunctionTemplateDecl>(D);
4634 CXXConversionDecl *Conv;
4635 if (ConvTemplate)
4636 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
4637 else
4638 Conv = cast<CXXConversionDecl>(D);
4639
4640 if (AllowRvalues) {
4641 // If we are initializing an rvalue reference, don't permit conversion
4642 // functions that return lvalues.
4643 if (!ConvTemplate && DeclType->isRValueReferenceType()) {
4644 const ReferenceType *RefType
4645 = Conv->getConversionType()->getAs<LValueReferenceType>();
4646 if (RefType && !RefType->getPointeeType()->isFunctionType())
4647 continue;
4648 }
4649
4650 if (!ConvTemplate &&
4651 S.CompareReferenceRelationship(
4652 DeclLoc,
4653 Conv->getConversionType()
4654 .getNonReferenceType()
4655 .getUnqualifiedType(),
4656 DeclType.getNonReferenceType().getUnqualifiedType()) ==
4657 Sema::Ref_Incompatible)
4658 continue;
4659 } else {
4660 // If the conversion function doesn't return a reference type,
4661 // it can't be considered for this conversion. An rvalue reference
4662 // is only acceptable if its referencee is a function type.
4663
4664 const ReferenceType *RefType =
4665 Conv->getConversionType()->getAs<ReferenceType>();
4666 if (!RefType ||
4667 (!RefType->isLValueReferenceType() &&
4668 !RefType->getPointeeType()->isFunctionType()))
4669 continue;
4670 }
4671
4672 if (ConvTemplate)
4673 S.AddTemplateConversionCandidate(
4674 ConvTemplate, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4675 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4676 else
4677 S.AddConversionCandidate(
4678 Conv, I.getPair(), ActingDC, Init, DeclType, CandidateSet,
4679 /*AllowObjCConversionOnExplicit=*/false, AllowExplicit);
4680 }
4681
4682 bool HadMultipleCandidates = (CandidateSet.size() > 1);
4683
4684 OverloadCandidateSet::iterator Best;
4685 switch (CandidateSet.BestViableFunction(S, DeclLoc, Best)) {
4686 case OR_Success:
4687 // C++ [over.ics.ref]p1:
4688 //
4689 // [...] If the parameter binds directly to the result of
4690 // applying a conversion function to the argument
4691 // expression, the implicit conversion sequence is a
4692 // user-defined conversion sequence (13.3.3.1.2), with the
4693 // second standard conversion sequence either an identity
4694 // conversion or, if the conversion function returns an
4695 // entity of a type that is a derived class of the parameter
4696 // type, a derived-to-base Conversion.
4697 if (!Best->FinalConversion.DirectBinding)
4698 return false;
4699
4700 ICS.setUserDefined();
4701 ICS.UserDefined.Before = Best->Conversions[0].Standard;
4702 ICS.UserDefined.After = Best->FinalConversion;
4703 ICS.UserDefined.HadMultipleCandidates = HadMultipleCandidates;
4704 ICS.UserDefined.ConversionFunction = Best->Function;
4705 ICS.UserDefined.FoundConversionFunction = Best->FoundDecl;
4706 ICS.UserDefined.EllipsisConversion = false;
4707 assert(ICS.UserDefined.After.ReferenceBinding &&
4708 ICS.UserDefined.After.DirectBinding &&
4709 "Expected a direct reference binding!");
4710 return true;
4711
4712 case OR_Ambiguous:
4713 ICS.setAmbiguous();
4714 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin();
4715 Cand != CandidateSet.end(); ++Cand)
4716 if (Cand->Best)
4717 ICS.Ambiguous.addConversion(Cand->FoundDecl, Cand->Function);
4718 return true;
4719
4720 case OR_No_Viable_Function:
4721 case OR_Deleted:
4722 // There was no suitable conversion, or we found a deleted
4723 // conversion; continue with other checks.
4724 return false;
4725 }
4726
4727 llvm_unreachable("Invalid OverloadResult!");
4728 }
4729
4730 /// Compute an implicit conversion sequence for reference
4731 /// initialization.
4732 static ImplicitConversionSequence
TryReferenceInit(Sema & S,Expr * Init,QualType DeclType,SourceLocation DeclLoc,bool SuppressUserConversions,bool AllowExplicit)4733 TryReferenceInit(Sema &S, Expr *Init, QualType DeclType,
4734 SourceLocation DeclLoc,
4735 bool SuppressUserConversions,
4736 bool AllowExplicit) {
4737 assert(DeclType->isReferenceType() && "Reference init needs a reference");
4738
4739 // Most paths end in a failed conversion.
4740 ImplicitConversionSequence ICS;
4741 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4742
4743 QualType T1 = DeclType->castAs<ReferenceType>()->getPointeeType();
4744 QualType T2 = Init->getType();
4745
4746 // If the initializer is the address of an overloaded function, try
4747 // to resolve the overloaded function. If all goes well, T2 is the
4748 // type of the resulting function.
4749 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
4750 DeclAccessPair Found;
4751 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(Init, DeclType,
4752 false, Found))
4753 T2 = Fn->getType();
4754 }
4755
4756 // Compute some basic properties of the types and the initializer.
4757 bool isRValRef = DeclType->isRValueReferenceType();
4758 Expr::Classification InitCategory = Init->Classify(S.Context);
4759
4760 Sema::ReferenceConversions RefConv;
4761 Sema::ReferenceCompareResult RefRelationship =
4762 S.CompareReferenceRelationship(DeclLoc, T1, T2, &RefConv);
4763
4764 auto SetAsReferenceBinding = [&](bool BindsDirectly) {
4765 ICS.setStandard();
4766 ICS.Standard.First = ICK_Identity;
4767 // FIXME: A reference binding can be a function conversion too. We should
4768 // consider that when ordering reference-to-function bindings.
4769 ICS.Standard.Second = (RefConv & Sema::ReferenceConversions::DerivedToBase)
4770 ? ICK_Derived_To_Base
4771 : (RefConv & Sema::ReferenceConversions::ObjC)
4772 ? ICK_Compatible_Conversion
4773 : ICK_Identity;
4774 // FIXME: As a speculative fix to a defect introduced by CWG2352, we rank
4775 // a reference binding that performs a non-top-level qualification
4776 // conversion as a qualification conversion, not as an identity conversion.
4777 ICS.Standard.Third = (RefConv &
4778 Sema::ReferenceConversions::NestedQualification)
4779 ? ICK_Qualification
4780 : ICK_Identity;
4781 ICS.Standard.setFromType(T2);
4782 ICS.Standard.setToType(0, T2);
4783 ICS.Standard.setToType(1, T1);
4784 ICS.Standard.setToType(2, T1);
4785 ICS.Standard.ReferenceBinding = true;
4786 ICS.Standard.DirectBinding = BindsDirectly;
4787 ICS.Standard.IsLvalueReference = !isRValRef;
4788 ICS.Standard.BindsToFunctionLvalue = T2->isFunctionType();
4789 ICS.Standard.BindsToRvalue = InitCategory.isRValue();
4790 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4791 ICS.Standard.ObjCLifetimeConversionBinding =
4792 (RefConv & Sema::ReferenceConversions::ObjCLifetime) != 0;
4793 ICS.Standard.CopyConstructor = nullptr;
4794 ICS.Standard.DeprecatedStringLiteralToCharPtr = false;
4795 };
4796
4797 // C++0x [dcl.init.ref]p5:
4798 // A reference to type "cv1 T1" is initialized by an expression
4799 // of type "cv2 T2" as follows:
4800
4801 // -- If reference is an lvalue reference and the initializer expression
4802 if (!isRValRef) {
4803 // -- is an lvalue (but is not a bit-field), and "cv1 T1" is
4804 // reference-compatible with "cv2 T2," or
4805 //
4806 // Per C++ [over.ics.ref]p4, we don't check the bit-field property here.
4807 if (InitCategory.isLValue() && RefRelationship == Sema::Ref_Compatible) {
4808 // C++ [over.ics.ref]p1:
4809 // When a parameter of reference type binds directly (8.5.3)
4810 // to an argument expression, the implicit conversion sequence
4811 // is the identity conversion, unless the argument expression
4812 // has a type that is a derived class of the parameter type,
4813 // in which case the implicit conversion sequence is a
4814 // derived-to-base Conversion (13.3.3.1).
4815 SetAsReferenceBinding(/*BindsDirectly=*/true);
4816
4817 // Nothing more to do: the inaccessibility/ambiguity check for
4818 // derived-to-base conversions is suppressed when we're
4819 // computing the implicit conversion sequence (C++
4820 // [over.best.ics]p2).
4821 return ICS;
4822 }
4823
4824 // -- has a class type (i.e., T2 is a class type), where T1 is
4825 // not reference-related to T2, and can be implicitly
4826 // converted to an lvalue of type "cv3 T3," where "cv1 T1"
4827 // is reference-compatible with "cv3 T3" 92) (this
4828 // conversion is selected by enumerating the applicable
4829 // conversion functions (13.3.1.6) and choosing the best
4830 // one through overload resolution (13.3)),
4831 if (!SuppressUserConversions && T2->isRecordType() &&
4832 S.isCompleteType(DeclLoc, T2) &&
4833 RefRelationship == Sema::Ref_Incompatible) {
4834 if (FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4835 Init, T2, /*AllowRvalues=*/false,
4836 AllowExplicit))
4837 return ICS;
4838 }
4839 }
4840
4841 // -- Otherwise, the reference shall be an lvalue reference to a
4842 // non-volatile const type (i.e., cv1 shall be const), or the reference
4843 // shall be an rvalue reference.
4844 if (!isRValRef && (!T1.isConstQualified() || T1.isVolatileQualified())) {
4845 if (InitCategory.isRValue() && RefRelationship != Sema::Ref_Incompatible)
4846 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, Init, DeclType);
4847 return ICS;
4848 }
4849
4850 // -- If the initializer expression
4851 //
4852 // -- is an xvalue, class prvalue, array prvalue or function
4853 // lvalue and "cv1 T1" is reference-compatible with "cv2 T2", or
4854 if (RefRelationship == Sema::Ref_Compatible &&
4855 (InitCategory.isXValue() ||
4856 (InitCategory.isPRValue() &&
4857 (T2->isRecordType() || T2->isArrayType())) ||
4858 (InitCategory.isLValue() && T2->isFunctionType()))) {
4859 // In C++11, this is always a direct binding. In C++98/03, it's a direct
4860 // binding unless we're binding to a class prvalue.
4861 // Note: Although xvalues wouldn't normally show up in C++98/03 code, we
4862 // allow the use of rvalue references in C++98/03 for the benefit of
4863 // standard library implementors; therefore, we need the xvalue check here.
4864 SetAsReferenceBinding(/*BindsDirectly=*/S.getLangOpts().CPlusPlus11 ||
4865 !(InitCategory.isPRValue() || T2->isRecordType()));
4866 return ICS;
4867 }
4868
4869 // -- has a class type (i.e., T2 is a class type), where T1 is not
4870 // reference-related to T2, and can be implicitly converted to
4871 // an xvalue, class prvalue, or function lvalue of type
4872 // "cv3 T3", where "cv1 T1" is reference-compatible with
4873 // "cv3 T3",
4874 //
4875 // then the reference is bound to the value of the initializer
4876 // expression in the first case and to the result of the conversion
4877 // in the second case (or, in either case, to an appropriate base
4878 // class subobject).
4879 if (!SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4880 T2->isRecordType() && S.isCompleteType(DeclLoc, T2) &&
4881 FindConversionForRefInit(S, ICS, DeclType, DeclLoc,
4882 Init, T2, /*AllowRvalues=*/true,
4883 AllowExplicit)) {
4884 // In the second case, if the reference is an rvalue reference
4885 // and the second standard conversion sequence of the
4886 // user-defined conversion sequence includes an lvalue-to-rvalue
4887 // conversion, the program is ill-formed.
4888 if (ICS.isUserDefined() && isRValRef &&
4889 ICS.UserDefined.After.First == ICK_Lvalue_To_Rvalue)
4890 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4891
4892 return ICS;
4893 }
4894
4895 // A temporary of function type cannot be created; don't even try.
4896 if (T1->isFunctionType())
4897 return ICS;
4898
4899 // -- Otherwise, a temporary of type "cv1 T1" is created and
4900 // initialized from the initializer expression using the
4901 // rules for a non-reference copy initialization (8.5). The
4902 // reference is then bound to the temporary. If T1 is
4903 // reference-related to T2, cv1 must be the same
4904 // cv-qualification as, or greater cv-qualification than,
4905 // cv2; otherwise, the program is ill-formed.
4906 if (RefRelationship == Sema::Ref_Related) {
4907 // If cv1 == cv2 or cv1 is a greater cv-qualified than cv2, then
4908 // we would be reference-compatible or reference-compatible with
4909 // added qualification. But that wasn't the case, so the reference
4910 // initialization fails.
4911 //
4912 // Note that we only want to check address spaces and cvr-qualifiers here.
4913 // ObjC GC, lifetime and unaligned qualifiers aren't important.
4914 Qualifiers T1Quals = T1.getQualifiers();
4915 Qualifiers T2Quals = T2.getQualifiers();
4916 T1Quals.removeObjCGCAttr();
4917 T1Quals.removeObjCLifetime();
4918 T2Quals.removeObjCGCAttr();
4919 T2Quals.removeObjCLifetime();
4920 // MS compiler ignores __unaligned qualifier for references; do the same.
4921 T1Quals.removeUnaligned();
4922 T2Quals.removeUnaligned();
4923 if (!T1Quals.compatiblyIncludes(T2Quals))
4924 return ICS;
4925 }
4926
4927 // If at least one of the types is a class type, the types are not
4928 // related, and we aren't allowed any user conversions, the
4929 // reference binding fails. This case is important for breaking
4930 // recursion, since TryImplicitConversion below will attempt to
4931 // create a temporary through the use of a copy constructor.
4932 if (SuppressUserConversions && RefRelationship == Sema::Ref_Incompatible &&
4933 (T1->isRecordType() || T2->isRecordType()))
4934 return ICS;
4935
4936 // If T1 is reference-related to T2 and the reference is an rvalue
4937 // reference, the initializer expression shall not be an lvalue.
4938 if (RefRelationship >= Sema::Ref_Related && isRValRef &&
4939 Init->Classify(S.Context).isLValue()) {
4940 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, Init, DeclType);
4941 return ICS;
4942 }
4943
4944 // C++ [over.ics.ref]p2:
4945 // When a parameter of reference type is not bound directly to
4946 // an argument expression, the conversion sequence is the one
4947 // required to convert the argument expression to the
4948 // underlying type of the reference according to
4949 // 13.3.3.1. Conceptually, this conversion sequence corresponds
4950 // to copy-initializing a temporary of the underlying type with
4951 // the argument expression. Any difference in top-level
4952 // cv-qualification is subsumed by the initialization itself
4953 // and does not constitute a conversion.
4954 ICS = TryImplicitConversion(S, Init, T1, SuppressUserConversions,
4955 AllowedExplicit::None,
4956 /*InOverloadResolution=*/false,
4957 /*CStyle=*/false,
4958 /*AllowObjCWritebackConversion=*/false,
4959 /*AllowObjCConversionOnExplicit=*/false);
4960
4961 // Of course, that's still a reference binding.
4962 if (ICS.isStandard()) {
4963 ICS.Standard.ReferenceBinding = true;
4964 ICS.Standard.IsLvalueReference = !isRValRef;
4965 ICS.Standard.BindsToFunctionLvalue = false;
4966 ICS.Standard.BindsToRvalue = true;
4967 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4968 ICS.Standard.ObjCLifetimeConversionBinding = false;
4969 } else if (ICS.isUserDefined()) {
4970 const ReferenceType *LValRefType =
4971 ICS.UserDefined.ConversionFunction->getReturnType()
4972 ->getAs<LValueReferenceType>();
4973
4974 // C++ [over.ics.ref]p3:
4975 // Except for an implicit object parameter, for which see 13.3.1, a
4976 // standard conversion sequence cannot be formed if it requires [...]
4977 // binding an rvalue reference to an lvalue other than a function
4978 // lvalue.
4979 // Note that the function case is not possible here.
4980 if (isRValRef && LValRefType) {
4981 ICS.setBad(BadConversionSequence::no_conversion, Init, DeclType);
4982 return ICS;
4983 }
4984
4985 ICS.UserDefined.After.ReferenceBinding = true;
4986 ICS.UserDefined.After.IsLvalueReference = !isRValRef;
4987 ICS.UserDefined.After.BindsToFunctionLvalue = false;
4988 ICS.UserDefined.After.BindsToRvalue = !LValRefType;
4989 ICS.UserDefined.After.BindsImplicitObjectArgumentWithoutRefQualifier = false;
4990 ICS.UserDefined.After.ObjCLifetimeConversionBinding = false;
4991 }
4992
4993 return ICS;
4994 }
4995
4996 static ImplicitConversionSequence
4997 TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
4998 bool SuppressUserConversions,
4999 bool InOverloadResolution,
5000 bool AllowObjCWritebackConversion,
5001 bool AllowExplicit = false);
5002
5003 /// TryListConversion - Try to copy-initialize a value of type ToType from the
5004 /// initializer list From.
5005 static ImplicitConversionSequence
TryListConversion(Sema & S,InitListExpr * From,QualType ToType,bool SuppressUserConversions,bool InOverloadResolution,bool AllowObjCWritebackConversion)5006 TryListConversion(Sema &S, InitListExpr *From, QualType ToType,
5007 bool SuppressUserConversions,
5008 bool InOverloadResolution,
5009 bool AllowObjCWritebackConversion) {
5010 // C++11 [over.ics.list]p1:
5011 // When an argument is an initializer list, it is not an expression and
5012 // special rules apply for converting it to a parameter type.
5013
5014 ImplicitConversionSequence Result;
5015 Result.setBad(BadConversionSequence::no_conversion, From, ToType);
5016
5017 // We need a complete type for what follows. With one C++20 exception,
5018 // incomplete types can never be initialized from init lists.
5019 QualType InitTy = ToType;
5020 const ArrayType *AT = S.Context.getAsArrayType(ToType);
5021 if (AT && S.getLangOpts().CPlusPlus20)
5022 if (const auto *IAT = dyn_cast<IncompleteArrayType>(AT))
5023 // C++20 allows list initialization of an incomplete array type.
5024 InitTy = IAT->getElementType();
5025 if (!S.isCompleteType(From->getBeginLoc(), InitTy))
5026 return Result;
5027
5028 // Per DR1467:
5029 // If the parameter type is a class X and the initializer list has a single
5030 // element of type cv U, where U is X or a class derived from X, the
5031 // implicit conversion sequence is the one required to convert the element
5032 // to the parameter type.
5033 //
5034 // Otherwise, if the parameter type is a character array [... ]
5035 // and the initializer list has a single element that is an
5036 // appropriately-typed string literal (8.5.2 [dcl.init.string]), the
5037 // implicit conversion sequence is the identity conversion.
5038 if (From->getNumInits() == 1) {
5039 if (ToType->isRecordType()) {
5040 QualType InitType = From->getInit(0)->getType();
5041 if (S.Context.hasSameUnqualifiedType(InitType, ToType) ||
5042 S.IsDerivedFrom(From->getBeginLoc(), InitType, ToType))
5043 return TryCopyInitialization(S, From->getInit(0), ToType,
5044 SuppressUserConversions,
5045 InOverloadResolution,
5046 AllowObjCWritebackConversion);
5047 }
5048
5049 if (AT && S.IsStringInit(From->getInit(0), AT)) {
5050 InitializedEntity Entity =
5051 InitializedEntity::InitializeParameter(S.Context, ToType,
5052 /*Consumed=*/false);
5053 if (S.CanPerformCopyInitialization(Entity, From)) {
5054 Result.setStandard();
5055 Result.Standard.setAsIdentityConversion();
5056 Result.Standard.setFromType(ToType);
5057 Result.Standard.setAllToTypes(ToType);
5058 return Result;
5059 }
5060 }
5061 }
5062
5063 // C++14 [over.ics.list]p2: Otherwise, if the parameter type [...] (below).
5064 // C++11 [over.ics.list]p2:
5065 // If the parameter type is std::initializer_list<X> or "array of X" and
5066 // all the elements can be implicitly converted to X, the implicit
5067 // conversion sequence is the worst conversion necessary to convert an
5068 // element of the list to X.
5069 //
5070 // C++14 [over.ics.list]p3:
5071 // Otherwise, if the parameter type is "array of N X", if the initializer
5072 // list has exactly N elements or if it has fewer than N elements and X is
5073 // default-constructible, and if all the elements of the initializer list
5074 // can be implicitly converted to X, the implicit conversion sequence is
5075 // the worst conversion necessary to convert an element of the list to X.
5076 if (AT || S.isStdInitializerList(ToType, &InitTy)) {
5077 unsigned e = From->getNumInits();
5078 ImplicitConversionSequence DfltElt;
5079 DfltElt.setBad(BadConversionSequence::no_conversion, QualType(),
5080 QualType());
5081 QualType ContTy = ToType;
5082 bool IsUnbounded = false;
5083 if (AT) {
5084 InitTy = AT->getElementType();
5085 if (ConstantArrayType const *CT = dyn_cast<ConstantArrayType>(AT)) {
5086 if (CT->getSize().ult(e)) {
5087 // Too many inits, fatally bad
5088 Result.setBad(BadConversionSequence::too_many_initializers, From,
5089 ToType);
5090 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5091 return Result;
5092 }
5093 if (CT->getSize().ugt(e)) {
5094 // Need an init from empty {}, is there one?
5095 InitListExpr EmptyList(S.Context, From->getEndLoc(), None,
5096 From->getEndLoc());
5097 EmptyList.setType(S.Context.VoidTy);
5098 DfltElt = TryListConversion(
5099 S, &EmptyList, InitTy, SuppressUserConversions,
5100 InOverloadResolution, AllowObjCWritebackConversion);
5101 if (DfltElt.isBad()) {
5102 // No {} init, fatally bad
5103 Result.setBad(BadConversionSequence::too_few_initializers, From,
5104 ToType);
5105 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5106 return Result;
5107 }
5108 }
5109 } else {
5110 assert(isa<IncompleteArrayType>(AT) && "Expected incomplete array");
5111 IsUnbounded = true;
5112 if (!e) {
5113 // Cannot convert to zero-sized.
5114 Result.setBad(BadConversionSequence::too_few_initializers, From,
5115 ToType);
5116 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5117 return Result;
5118 }
5119 llvm::APInt Size(S.Context.getTypeSize(S.Context.getSizeType()), e);
5120 ContTy = S.Context.getConstantArrayType(InitTy, Size, nullptr,
5121 ArrayType::Normal, 0);
5122 }
5123 }
5124
5125 Result.setStandard();
5126 Result.Standard.setAsIdentityConversion();
5127 Result.Standard.setFromType(InitTy);
5128 Result.Standard.setAllToTypes(InitTy);
5129 for (unsigned i = 0; i < e; ++i) {
5130 Expr *Init = From->getInit(i);
5131 ImplicitConversionSequence ICS = TryCopyInitialization(
5132 S, Init, InitTy, SuppressUserConversions, InOverloadResolution,
5133 AllowObjCWritebackConversion);
5134
5135 // Keep the worse conversion seen so far.
5136 // FIXME: Sequences are not totally ordered, so 'worse' can be
5137 // ambiguous. CWG has been informed.
5138 if (CompareImplicitConversionSequences(S, From->getBeginLoc(), ICS,
5139 Result) ==
5140 ImplicitConversionSequence::Worse) {
5141 Result = ICS;
5142 // Bail as soon as we find something unconvertible.
5143 if (Result.isBad()) {
5144 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5145 return Result;
5146 }
5147 }
5148 }
5149
5150 // If we needed any implicit {} initialization, compare that now.
5151 // over.ics.list/6 indicates we should compare that conversion. Again CWG
5152 // has been informed that this might not be the best thing.
5153 if (!DfltElt.isBad() && CompareImplicitConversionSequences(
5154 S, From->getEndLoc(), DfltElt, Result) ==
5155 ImplicitConversionSequence::Worse)
5156 Result = DfltElt;
5157 // Record the type being initialized so that we may compare sequences
5158 Result.setInitializerListContainerType(ContTy, IsUnbounded);
5159 return Result;
5160 }
5161
5162 // C++14 [over.ics.list]p4:
5163 // C++11 [over.ics.list]p3:
5164 // Otherwise, if the parameter is a non-aggregate class X and overload
5165 // resolution chooses a single best constructor [...] the implicit
5166 // conversion sequence is a user-defined conversion sequence. If multiple
5167 // constructors are viable but none is better than the others, the
5168 // implicit conversion sequence is a user-defined conversion sequence.
5169 if (ToType->isRecordType() && !ToType->isAggregateType()) {
5170 // This function can deal with initializer lists.
5171 return TryUserDefinedConversion(S, From, ToType, SuppressUserConversions,
5172 AllowedExplicit::None,
5173 InOverloadResolution, /*CStyle=*/false,
5174 AllowObjCWritebackConversion,
5175 /*AllowObjCConversionOnExplicit=*/false);
5176 }
5177
5178 // C++14 [over.ics.list]p5:
5179 // C++11 [over.ics.list]p4:
5180 // Otherwise, if the parameter has an aggregate type which can be
5181 // initialized from the initializer list [...] the implicit conversion
5182 // sequence is a user-defined conversion sequence.
5183 if (ToType->isAggregateType()) {
5184 // Type is an aggregate, argument is an init list. At this point it comes
5185 // down to checking whether the initialization works.
5186 // FIXME: Find out whether this parameter is consumed or not.
5187 InitializedEntity Entity =
5188 InitializedEntity::InitializeParameter(S.Context, ToType,
5189 /*Consumed=*/false);
5190 if (S.CanPerformAggregateInitializationForOverloadResolution(Entity,
5191 From)) {
5192 Result.setUserDefined();
5193 Result.UserDefined.Before.setAsIdentityConversion();
5194 // Initializer lists don't have a type.
5195 Result.UserDefined.Before.setFromType(QualType());
5196 Result.UserDefined.Before.setAllToTypes(QualType());
5197
5198 Result.UserDefined.After.setAsIdentityConversion();
5199 Result.UserDefined.After.setFromType(ToType);
5200 Result.UserDefined.After.setAllToTypes(ToType);
5201 Result.UserDefined.ConversionFunction = nullptr;
5202 }
5203 return Result;
5204 }
5205
5206 // C++14 [over.ics.list]p6:
5207 // C++11 [over.ics.list]p5:
5208 // Otherwise, if the parameter is a reference, see 13.3.3.1.4.
5209 if (ToType->isReferenceType()) {
5210 // The standard is notoriously unclear here, since 13.3.3.1.4 doesn't
5211 // mention initializer lists in any way. So we go by what list-
5212 // initialization would do and try to extrapolate from that.
5213
5214 QualType T1 = ToType->castAs<ReferenceType>()->getPointeeType();
5215
5216 // If the initializer list has a single element that is reference-related
5217 // to the parameter type, we initialize the reference from that.
5218 if (From->getNumInits() == 1) {
5219 Expr *Init = From->getInit(0);
5220
5221 QualType T2 = Init->getType();
5222
5223 // If the initializer is the address of an overloaded function, try
5224 // to resolve the overloaded function. If all goes well, T2 is the
5225 // type of the resulting function.
5226 if (S.Context.getCanonicalType(T2) == S.Context.OverloadTy) {
5227 DeclAccessPair Found;
5228 if (FunctionDecl *Fn = S.ResolveAddressOfOverloadedFunction(
5229 Init, ToType, false, Found))
5230 T2 = Fn->getType();
5231 }
5232
5233 // Compute some basic properties of the types and the initializer.
5234 Sema::ReferenceCompareResult RefRelationship =
5235 S.CompareReferenceRelationship(From->getBeginLoc(), T1, T2);
5236
5237 if (RefRelationship >= Sema::Ref_Related) {
5238 return TryReferenceInit(S, Init, ToType, /*FIXME*/ From->getBeginLoc(),
5239 SuppressUserConversions,
5240 /*AllowExplicit=*/false);
5241 }
5242 }
5243
5244 // Otherwise, we bind the reference to a temporary created from the
5245 // initializer list.
5246 Result = TryListConversion(S, From, T1, SuppressUserConversions,
5247 InOverloadResolution,
5248 AllowObjCWritebackConversion);
5249 if (Result.isFailure())
5250 return Result;
5251 assert(!Result.isEllipsis() &&
5252 "Sub-initialization cannot result in ellipsis conversion.");
5253
5254 // Can we even bind to a temporary?
5255 if (ToType->isRValueReferenceType() ||
5256 (T1.isConstQualified() && !T1.isVolatileQualified())) {
5257 StandardConversionSequence &SCS = Result.isStandard() ? Result.Standard :
5258 Result.UserDefined.After;
5259 SCS.ReferenceBinding = true;
5260 SCS.IsLvalueReference = ToType->isLValueReferenceType();
5261 SCS.BindsToRvalue = true;
5262 SCS.BindsToFunctionLvalue = false;
5263 SCS.BindsImplicitObjectArgumentWithoutRefQualifier = false;
5264 SCS.ObjCLifetimeConversionBinding = false;
5265 } else
5266 Result.setBad(BadConversionSequence::lvalue_ref_to_rvalue,
5267 From, ToType);
5268 return Result;
5269 }
5270
5271 // C++14 [over.ics.list]p7:
5272 // C++11 [over.ics.list]p6:
5273 // Otherwise, if the parameter type is not a class:
5274 if (!ToType->isRecordType()) {
5275 // - if the initializer list has one element that is not itself an
5276 // initializer list, the implicit conversion sequence is the one
5277 // required to convert the element to the parameter type.
5278 unsigned NumInits = From->getNumInits();
5279 if (NumInits == 1 && !isa<InitListExpr>(From->getInit(0)))
5280 Result = TryCopyInitialization(S, From->getInit(0), ToType,
5281 SuppressUserConversions,
5282 InOverloadResolution,
5283 AllowObjCWritebackConversion);
5284 // - if the initializer list has no elements, the implicit conversion
5285 // sequence is the identity conversion.
5286 else if (NumInits == 0) {
5287 Result.setStandard();
5288 Result.Standard.setAsIdentityConversion();
5289 Result.Standard.setFromType(ToType);
5290 Result.Standard.setAllToTypes(ToType);
5291 }
5292 return Result;
5293 }
5294
5295 // C++14 [over.ics.list]p8:
5296 // C++11 [over.ics.list]p7:
5297 // In all cases other than those enumerated above, no conversion is possible
5298 return Result;
5299 }
5300
5301 /// TryCopyInitialization - Try to copy-initialize a value of type
5302 /// ToType from the expression From. Return the implicit conversion
5303 /// sequence required to pass this argument, which may be a bad
5304 /// conversion sequence (meaning that the argument cannot be passed to
5305 /// a parameter of this type). If @p SuppressUserConversions, then we
5306 /// do not permit any user-defined conversion sequences.
5307 static ImplicitConversionSequence
TryCopyInitialization(Sema & S,Expr * From,QualType ToType,bool SuppressUserConversions,bool InOverloadResolution,bool AllowObjCWritebackConversion,bool AllowExplicit)5308 TryCopyInitialization(Sema &S, Expr *From, QualType ToType,
5309 bool SuppressUserConversions,
5310 bool InOverloadResolution,
5311 bool AllowObjCWritebackConversion,
5312 bool AllowExplicit) {
5313 if (InitListExpr *FromInitList = dyn_cast<InitListExpr>(From))
5314 return TryListConversion(S, FromInitList, ToType, SuppressUserConversions,
5315 InOverloadResolution,AllowObjCWritebackConversion);
5316
5317 if (ToType->isReferenceType())
5318 return TryReferenceInit(S, From, ToType,
5319 /*FIXME:*/ From->getBeginLoc(),
5320 SuppressUserConversions, AllowExplicit);
5321
5322 return TryImplicitConversion(S, From, ToType,
5323 SuppressUserConversions,
5324 AllowedExplicit::None,
5325 InOverloadResolution,
5326 /*CStyle=*/false,
5327 AllowObjCWritebackConversion,
5328 /*AllowObjCConversionOnExplicit=*/false);
5329 }
5330
TryCopyInitialization(const CanQualType FromQTy,const CanQualType ToQTy,Sema & S,SourceLocation Loc,ExprValueKind FromVK)5331 static bool TryCopyInitialization(const CanQualType FromQTy,
5332 const CanQualType ToQTy,
5333 Sema &S,
5334 SourceLocation Loc,
5335 ExprValueKind FromVK) {
5336 OpaqueValueExpr TmpExpr(Loc, FromQTy, FromVK);
5337 ImplicitConversionSequence ICS =
5338 TryCopyInitialization(S, &TmpExpr, ToQTy, true, true, false);
5339
5340 return !ICS.isBad();
5341 }
5342
5343 /// TryObjectArgumentInitialization - Try to initialize the object
5344 /// parameter of the given member function (@c Method) from the
5345 /// expression @p From.
5346 static ImplicitConversionSequence
TryObjectArgumentInitialization(Sema & S,SourceLocation Loc,QualType FromType,Expr::Classification FromClassification,CXXMethodDecl * Method,CXXRecordDecl * ActingContext)5347 TryObjectArgumentInitialization(Sema &S, SourceLocation Loc, QualType FromType,
5348 Expr::Classification FromClassification,
5349 CXXMethodDecl *Method,
5350 CXXRecordDecl *ActingContext) {
5351 QualType ClassType = S.Context.getTypeDeclType(ActingContext);
5352 // [class.dtor]p2: A destructor can be invoked for a const, volatile or
5353 // const volatile object.
5354 Qualifiers Quals = Method->getMethodQualifiers();
5355 if (isa<CXXDestructorDecl>(Method)) {
5356 Quals.addConst();
5357 Quals.addVolatile();
5358 }
5359
5360 QualType ImplicitParamType = S.Context.getQualifiedType(ClassType, Quals);
5361
5362 // Set up the conversion sequence as a "bad" conversion, to allow us
5363 // to exit early.
5364 ImplicitConversionSequence ICS;
5365
5366 // We need to have an object of class type.
5367 if (const PointerType *PT = FromType->getAs<PointerType>()) {
5368 FromType = PT->getPointeeType();
5369
5370 // When we had a pointer, it's implicitly dereferenced, so we
5371 // better have an lvalue.
5372 assert(FromClassification.isLValue());
5373 }
5374
5375 assert(FromType->isRecordType());
5376
5377 // C++0x [over.match.funcs]p4:
5378 // For non-static member functions, the type of the implicit object
5379 // parameter is
5380 //
5381 // - "lvalue reference to cv X" for functions declared without a
5382 // ref-qualifier or with the & ref-qualifier
5383 // - "rvalue reference to cv X" for functions declared with the &&
5384 // ref-qualifier
5385 //
5386 // where X is the class of which the function is a member and cv is the
5387 // cv-qualification on the member function declaration.
5388 //
5389 // However, when finding an implicit conversion sequence for the argument, we
5390 // are not allowed to perform user-defined conversions
5391 // (C++ [over.match.funcs]p5). We perform a simplified version of
5392 // reference binding here, that allows class rvalues to bind to
5393 // non-constant references.
5394
5395 // First check the qualifiers.
5396 QualType FromTypeCanon = S.Context.getCanonicalType(FromType);
5397 if (ImplicitParamType.getCVRQualifiers()
5398 != FromTypeCanon.getLocalCVRQualifiers() &&
5399 !ImplicitParamType.isAtLeastAsQualifiedAs(FromTypeCanon)) {
5400 ICS.setBad(BadConversionSequence::bad_qualifiers,
5401 FromType, ImplicitParamType);
5402 return ICS;
5403 }
5404
5405 if (FromTypeCanon.hasAddressSpace()) {
5406 Qualifiers QualsImplicitParamType = ImplicitParamType.getQualifiers();
5407 Qualifiers QualsFromType = FromTypeCanon.getQualifiers();
5408 if (!QualsImplicitParamType.isAddressSpaceSupersetOf(QualsFromType)) {
5409 ICS.setBad(BadConversionSequence::bad_qualifiers,
5410 FromType, ImplicitParamType);
5411 return ICS;
5412 }
5413 }
5414
5415 // Check that we have either the same type or a derived type. It
5416 // affects the conversion rank.
5417 QualType ClassTypeCanon = S.Context.getCanonicalType(ClassType);
5418 ImplicitConversionKind SecondKind;
5419 if (ClassTypeCanon == FromTypeCanon.getLocalUnqualifiedType()) {
5420 SecondKind = ICK_Identity;
5421 } else if (S.IsDerivedFrom(Loc, FromType, ClassType))
5422 SecondKind = ICK_Derived_To_Base;
5423 else {
5424 ICS.setBad(BadConversionSequence::unrelated_class,
5425 FromType, ImplicitParamType);
5426 return ICS;
5427 }
5428
5429 // Check the ref-qualifier.
5430 switch (Method->getRefQualifier()) {
5431 case RQ_None:
5432 // Do nothing; we don't care about lvalueness or rvalueness.
5433 break;
5434
5435 case RQ_LValue:
5436 if (!FromClassification.isLValue() && !Quals.hasOnlyConst()) {
5437 // non-const lvalue reference cannot bind to an rvalue
5438 ICS.setBad(BadConversionSequence::lvalue_ref_to_rvalue, FromType,
5439 ImplicitParamType);
5440 return ICS;
5441 }
5442 break;
5443
5444 case RQ_RValue:
5445 if (!FromClassification.isRValue()) {
5446 // rvalue reference cannot bind to an lvalue
5447 ICS.setBad(BadConversionSequence::rvalue_ref_to_lvalue, FromType,
5448 ImplicitParamType);
5449 return ICS;
5450 }
5451 break;
5452 }
5453
5454 // Success. Mark this as a reference binding.
5455 ICS.setStandard();
5456 ICS.Standard.setAsIdentityConversion();
5457 ICS.Standard.Second = SecondKind;
5458 ICS.Standard.setFromType(FromType);
5459 ICS.Standard.setAllToTypes(ImplicitParamType);
5460 ICS.Standard.ReferenceBinding = true;
5461 ICS.Standard.DirectBinding = true;
5462 ICS.Standard.IsLvalueReference = Method->getRefQualifier() != RQ_RValue;
5463 ICS.Standard.BindsToFunctionLvalue = false;
5464 ICS.Standard.BindsToRvalue = FromClassification.isRValue();
5465 ICS.Standard.BindsImplicitObjectArgumentWithoutRefQualifier
5466 = (Method->getRefQualifier() == RQ_None);
5467 return ICS;
5468 }
5469
5470 /// PerformObjectArgumentInitialization - Perform initialization of
5471 /// the implicit object parameter for the given Method with the given
5472 /// expression.
5473 ExprResult
PerformObjectArgumentInitialization(Expr * From,NestedNameSpecifier * Qualifier,NamedDecl * FoundDecl,CXXMethodDecl * Method)5474 Sema::PerformObjectArgumentInitialization(Expr *From,
5475 NestedNameSpecifier *Qualifier,
5476 NamedDecl *FoundDecl,
5477 CXXMethodDecl *Method) {
5478 QualType FromRecordType, DestType;
5479 QualType ImplicitParamRecordType =
5480 Method->getThisType()->castAs<PointerType>()->getPointeeType();
5481
5482 Expr::Classification FromClassification;
5483 if (const PointerType *PT = From->getType()->getAs<PointerType>()) {
5484 FromRecordType = PT->getPointeeType();
5485 DestType = Method->getThisType();
5486 FromClassification = Expr::Classification::makeSimpleLValue();
5487 } else {
5488 FromRecordType = From->getType();
5489 DestType = ImplicitParamRecordType;
5490 FromClassification = From->Classify(Context);
5491
5492 // When performing member access on a prvalue, materialize a temporary.
5493 if (From->isPRValue()) {
5494 From = CreateMaterializeTemporaryExpr(FromRecordType, From,
5495 Method->getRefQualifier() !=
5496 RefQualifierKind::RQ_RValue);
5497 }
5498 }
5499
5500 // Note that we always use the true parent context when performing
5501 // the actual argument initialization.
5502 ImplicitConversionSequence ICS = TryObjectArgumentInitialization(
5503 *this, From->getBeginLoc(), From->getType(), FromClassification, Method,
5504 Method->getParent());
5505 if (ICS.isBad()) {
5506 switch (ICS.Bad.Kind) {
5507 case BadConversionSequence::bad_qualifiers: {
5508 Qualifiers FromQs = FromRecordType.getQualifiers();
5509 Qualifiers ToQs = DestType.getQualifiers();
5510 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
5511 if (CVR) {
5512 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_cvr)
5513 << Method->getDeclName() << FromRecordType << (CVR - 1)
5514 << From->getSourceRange();
5515 Diag(Method->getLocation(), diag::note_previous_decl)
5516 << Method->getDeclName();
5517 return ExprError();
5518 }
5519 break;
5520 }
5521
5522 case BadConversionSequence::lvalue_ref_to_rvalue:
5523 case BadConversionSequence::rvalue_ref_to_lvalue: {
5524 bool IsRValueQualified =
5525 Method->getRefQualifier() == RefQualifierKind::RQ_RValue;
5526 Diag(From->getBeginLoc(), diag::err_member_function_call_bad_ref)
5527 << Method->getDeclName() << FromClassification.isRValue()
5528 << IsRValueQualified;
5529 Diag(Method->getLocation(), diag::note_previous_decl)
5530 << Method->getDeclName();
5531 return ExprError();
5532 }
5533
5534 case BadConversionSequence::no_conversion:
5535 case BadConversionSequence::unrelated_class:
5536 break;
5537
5538 case BadConversionSequence::too_few_initializers:
5539 case BadConversionSequence::too_many_initializers:
5540 llvm_unreachable("Lists are not objects");
5541 }
5542
5543 return Diag(From->getBeginLoc(), diag::err_member_function_call_bad_type)
5544 << ImplicitParamRecordType << FromRecordType
5545 << From->getSourceRange();
5546 }
5547
5548 if (ICS.Standard.Second == ICK_Derived_To_Base) {
5549 ExprResult FromRes =
5550 PerformObjectMemberConversion(From, Qualifier, FoundDecl, Method);
5551 if (FromRes.isInvalid())
5552 return ExprError();
5553 From = FromRes.get();
5554 }
5555
5556 if (!Context.hasSameType(From->getType(), DestType)) {
5557 CastKind CK;
5558 QualType PteeTy = DestType->getPointeeType();
5559 LangAS DestAS =
5560 PteeTy.isNull() ? DestType.getAddressSpace() : PteeTy.getAddressSpace();
5561 if (FromRecordType.getAddressSpace() != DestAS)
5562 CK = CK_AddressSpaceConversion;
5563 else
5564 CK = CK_NoOp;
5565 From = ImpCastExprToType(From, DestType, CK, From->getValueKind()).get();
5566 }
5567 return From;
5568 }
5569
5570 /// TryContextuallyConvertToBool - Attempt to contextually convert the
5571 /// expression From to bool (C++0x [conv]p3).
5572 static ImplicitConversionSequence
TryContextuallyConvertToBool(Sema & S,Expr * From)5573 TryContextuallyConvertToBool(Sema &S, Expr *From) {
5574 // C++ [dcl.init]/17.8:
5575 // - Otherwise, if the initialization is direct-initialization, the source
5576 // type is std::nullptr_t, and the destination type is bool, the initial
5577 // value of the object being initialized is false.
5578 if (From->getType()->isNullPtrType())
5579 return ImplicitConversionSequence::getNullptrToBool(From->getType(),
5580 S.Context.BoolTy,
5581 From->isGLValue());
5582
5583 // All other direct-initialization of bool is equivalent to an implicit
5584 // conversion to bool in which explicit conversions are permitted.
5585 return TryImplicitConversion(S, From, S.Context.BoolTy,
5586 /*SuppressUserConversions=*/false,
5587 AllowedExplicit::Conversions,
5588 /*InOverloadResolution=*/false,
5589 /*CStyle=*/false,
5590 /*AllowObjCWritebackConversion=*/false,
5591 /*AllowObjCConversionOnExplicit=*/false);
5592 }
5593
5594 /// PerformContextuallyConvertToBool - Perform a contextual conversion
5595 /// of the expression From to bool (C++0x [conv]p3).
PerformContextuallyConvertToBool(Expr * From)5596 ExprResult Sema::PerformContextuallyConvertToBool(Expr *From) {
5597 if (checkPlaceholderForOverload(*this, From))
5598 return ExprError();
5599
5600 ImplicitConversionSequence ICS = TryContextuallyConvertToBool(*this, From);
5601 if (!ICS.isBad())
5602 return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
5603
5604 if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
5605 return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
5606 << From->getType() << From->getSourceRange();
5607 return ExprError();
5608 }
5609
5610 /// Check that the specified conversion is permitted in a converted constant
5611 /// expression, according to C++11 [expr.const]p3. Return true if the conversion
5612 /// is acceptable.
CheckConvertedConstantConversions(Sema & S,StandardConversionSequence & SCS)5613 static bool CheckConvertedConstantConversions(Sema &S,
5614 StandardConversionSequence &SCS) {
5615 // Since we know that the target type is an integral or unscoped enumeration
5616 // type, most conversion kinds are impossible. All possible First and Third
5617 // conversions are fine.
5618 switch (SCS.Second) {
5619 case ICK_Identity:
5620 case ICK_Integral_Promotion:
5621 case ICK_Integral_Conversion: // Narrowing conversions are checked elsewhere.
5622 case ICK_Zero_Queue_Conversion:
5623 return true;
5624
5625 case ICK_Boolean_Conversion:
5626 // Conversion from an integral or unscoped enumeration type to bool is
5627 // classified as ICK_Boolean_Conversion, but it's also arguably an integral
5628 // conversion, so we allow it in a converted constant expression.
5629 //
5630 // FIXME: Per core issue 1407, we should not allow this, but that breaks
5631 // a lot of popular code. We should at least add a warning for this
5632 // (non-conforming) extension.
5633 return SCS.getFromType()->isIntegralOrUnscopedEnumerationType() &&
5634 SCS.getToType(2)->isBooleanType();
5635
5636 case ICK_Pointer_Conversion:
5637 case ICK_Pointer_Member:
5638 // C++1z: null pointer conversions and null member pointer conversions are
5639 // only permitted if the source type is std::nullptr_t.
5640 return SCS.getFromType()->isNullPtrType();
5641
5642 case ICK_Floating_Promotion:
5643 case ICK_Complex_Promotion:
5644 case ICK_Floating_Conversion:
5645 case ICK_Complex_Conversion:
5646 case ICK_Floating_Integral:
5647 case ICK_Compatible_Conversion:
5648 case ICK_Derived_To_Base:
5649 case ICK_Vector_Conversion:
5650 case ICK_SVE_Vector_Conversion:
5651 case ICK_Vector_Splat:
5652 case ICK_Complex_Real:
5653 case ICK_Block_Pointer_Conversion:
5654 case ICK_TransparentUnionConversion:
5655 case ICK_Writeback_Conversion:
5656 case ICK_Zero_Event_Conversion:
5657 case ICK_C_Only_Conversion:
5658 case ICK_Incompatible_Pointer_Conversion:
5659 return false;
5660
5661 case ICK_Lvalue_To_Rvalue:
5662 case ICK_Array_To_Pointer:
5663 case ICK_Function_To_Pointer:
5664 llvm_unreachable("found a first conversion kind in Second");
5665
5666 case ICK_Function_Conversion:
5667 case ICK_Qualification:
5668 llvm_unreachable("found a third conversion kind in Second");
5669
5670 case ICK_Num_Conversion_Kinds:
5671 break;
5672 }
5673
5674 llvm_unreachable("unknown conversion kind");
5675 }
5676
5677 /// CheckConvertedConstantExpression - Check that the expression From is a
5678 /// converted constant expression of type T, perform the conversion and produce
5679 /// the converted expression, per C++11 [expr.const]p3.
CheckConvertedConstantExpression(Sema & S,Expr * From,QualType T,APValue & Value,Sema::CCEKind CCE,bool RequireInt,NamedDecl * Dest)5680 static ExprResult CheckConvertedConstantExpression(Sema &S, Expr *From,
5681 QualType T, APValue &Value,
5682 Sema::CCEKind CCE,
5683 bool RequireInt,
5684 NamedDecl *Dest) {
5685 assert(S.getLangOpts().CPlusPlus11 &&
5686 "converted constant expression outside C++11");
5687
5688 if (checkPlaceholderForOverload(S, From))
5689 return ExprError();
5690
5691 // C++1z [expr.const]p3:
5692 // A converted constant expression of type T is an expression,
5693 // implicitly converted to type T, where the converted
5694 // expression is a constant expression and the implicit conversion
5695 // sequence contains only [... list of conversions ...].
5696 ImplicitConversionSequence ICS =
5697 (CCE == Sema::CCEK_ExplicitBool || CCE == Sema::CCEK_Noexcept)
5698 ? TryContextuallyConvertToBool(S, From)
5699 : TryCopyInitialization(S, From, T,
5700 /*SuppressUserConversions=*/false,
5701 /*InOverloadResolution=*/false,
5702 /*AllowObjCWritebackConversion=*/false,
5703 /*AllowExplicit=*/false);
5704 StandardConversionSequence *SCS = nullptr;
5705 switch (ICS.getKind()) {
5706 case ImplicitConversionSequence::StandardConversion:
5707 SCS = &ICS.Standard;
5708 break;
5709 case ImplicitConversionSequence::UserDefinedConversion:
5710 if (T->isRecordType())
5711 SCS = &ICS.UserDefined.Before;
5712 else
5713 SCS = &ICS.UserDefined.After;
5714 break;
5715 case ImplicitConversionSequence::AmbiguousConversion:
5716 case ImplicitConversionSequence::BadConversion:
5717 if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
5718 return S.Diag(From->getBeginLoc(),
5719 diag::err_typecheck_converted_constant_expression)
5720 << From->getType() << From->getSourceRange() << T;
5721 return ExprError();
5722
5723 case ImplicitConversionSequence::EllipsisConversion:
5724 llvm_unreachable("ellipsis conversion in converted constant expression");
5725 }
5726
5727 // Check that we would only use permitted conversions.
5728 if (!CheckConvertedConstantConversions(S, *SCS)) {
5729 return S.Diag(From->getBeginLoc(),
5730 diag::err_typecheck_converted_constant_expression_disallowed)
5731 << From->getType() << From->getSourceRange() << T;
5732 }
5733 // [...] and where the reference binding (if any) binds directly.
5734 if (SCS->ReferenceBinding && !SCS->DirectBinding) {
5735 return S.Diag(From->getBeginLoc(),
5736 diag::err_typecheck_converted_constant_expression_indirect)
5737 << From->getType() << From->getSourceRange() << T;
5738 }
5739
5740 // Usually we can simply apply the ImplicitConversionSequence we formed
5741 // earlier, but that's not guaranteed to work when initializing an object of
5742 // class type.
5743 ExprResult Result;
5744 if (T->isRecordType()) {
5745 assert(CCE == Sema::CCEK_TemplateArg &&
5746 "unexpected class type converted constant expr");
5747 Result = S.PerformCopyInitialization(
5748 InitializedEntity::InitializeTemplateParameter(
5749 T, cast<NonTypeTemplateParmDecl>(Dest)),
5750 SourceLocation(), From);
5751 } else {
5752 Result = S.PerformImplicitConversion(From, T, ICS, Sema::AA_Converting);
5753 }
5754 if (Result.isInvalid())
5755 return Result;
5756
5757 // C++2a [intro.execution]p5:
5758 // A full-expression is [...] a constant-expression [...]
5759 Result =
5760 S.ActOnFinishFullExpr(Result.get(), From->getExprLoc(),
5761 /*DiscardedValue=*/false, /*IsConstexpr=*/true);
5762 if (Result.isInvalid())
5763 return Result;
5764
5765 // Check for a narrowing implicit conversion.
5766 bool ReturnPreNarrowingValue = false;
5767 APValue PreNarrowingValue;
5768 QualType PreNarrowingType;
5769 switch (SCS->getNarrowingKind(S.Context, Result.get(), PreNarrowingValue,
5770 PreNarrowingType)) {
5771 case NK_Dependent_Narrowing:
5772 // Implicit conversion to a narrower type, but the expression is
5773 // value-dependent so we can't tell whether it's actually narrowing.
5774 case NK_Variable_Narrowing:
5775 // Implicit conversion to a narrower type, and the value is not a constant
5776 // expression. We'll diagnose this in a moment.
5777 case NK_Not_Narrowing:
5778 break;
5779
5780 case NK_Constant_Narrowing:
5781 if (CCE == Sema::CCEK_ArrayBound &&
5782 PreNarrowingType->isIntegralOrEnumerationType() &&
5783 PreNarrowingValue.isInt()) {
5784 // Don't diagnose array bound narrowing here; we produce more precise
5785 // errors by allowing the un-narrowed value through.
5786 ReturnPreNarrowingValue = true;
5787 break;
5788 }
5789 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5790 << CCE << /*Constant*/ 1
5791 << PreNarrowingValue.getAsString(S.Context, PreNarrowingType) << T;
5792 break;
5793
5794 case NK_Type_Narrowing:
5795 // FIXME: It would be better to diagnose that the expression is not a
5796 // constant expression.
5797 S.Diag(From->getBeginLoc(), diag::ext_cce_narrowing)
5798 << CCE << /*Constant*/ 0 << From->getType() << T;
5799 break;
5800 }
5801
5802 if (Result.get()->isValueDependent()) {
5803 Value = APValue();
5804 return Result;
5805 }
5806
5807 // Check the expression is a constant expression.
5808 SmallVector<PartialDiagnosticAt, 8> Notes;
5809 Expr::EvalResult Eval;
5810 Eval.Diag = &Notes;
5811
5812 ConstantExprKind Kind;
5813 if (CCE == Sema::CCEK_TemplateArg && T->isRecordType())
5814 Kind = ConstantExprKind::ClassTemplateArgument;
5815 else if (CCE == Sema::CCEK_TemplateArg)
5816 Kind = ConstantExprKind::NonClassTemplateArgument;
5817 else
5818 Kind = ConstantExprKind::Normal;
5819
5820 if (!Result.get()->EvaluateAsConstantExpr(Eval, S.Context, Kind) ||
5821 (RequireInt && !Eval.Val.isInt())) {
5822 // The expression can't be folded, so we can't keep it at this position in
5823 // the AST.
5824 Result = ExprError();
5825 } else {
5826 Value = Eval.Val;
5827
5828 if (Notes.empty()) {
5829 // It's a constant expression.
5830 Expr *E = ConstantExpr::Create(S.Context, Result.get(), Value);
5831 if (ReturnPreNarrowingValue)
5832 Value = std::move(PreNarrowingValue);
5833 return E;
5834 }
5835 }
5836
5837 // It's not a constant expression. Produce an appropriate diagnostic.
5838 if (Notes.size() == 1 &&
5839 Notes[0].second.getDiagID() == diag::note_invalid_subexpr_in_const_expr) {
5840 S.Diag(Notes[0].first, diag::err_expr_not_cce) << CCE;
5841 } else if (!Notes.empty() && Notes[0].second.getDiagID() ==
5842 diag::note_constexpr_invalid_template_arg) {
5843 Notes[0].second.setDiagID(diag::err_constexpr_invalid_template_arg);
5844 for (unsigned I = 0; I < Notes.size(); ++I)
5845 S.Diag(Notes[I].first, Notes[I].second);
5846 } else {
5847 S.Diag(From->getBeginLoc(), diag::err_expr_not_cce)
5848 << CCE << From->getSourceRange();
5849 for (unsigned I = 0; I < Notes.size(); ++I)
5850 S.Diag(Notes[I].first, Notes[I].second);
5851 }
5852 return ExprError();
5853 }
5854
CheckConvertedConstantExpression(Expr * From,QualType T,APValue & Value,CCEKind CCE,NamedDecl * Dest)5855 ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5856 APValue &Value, CCEKind CCE,
5857 NamedDecl *Dest) {
5858 return ::CheckConvertedConstantExpression(*this, From, T, Value, CCE, false,
5859 Dest);
5860 }
5861
CheckConvertedConstantExpression(Expr * From,QualType T,llvm::APSInt & Value,CCEKind CCE)5862 ExprResult Sema::CheckConvertedConstantExpression(Expr *From, QualType T,
5863 llvm::APSInt &Value,
5864 CCEKind CCE) {
5865 assert(T->isIntegralOrEnumerationType() && "unexpected converted const type");
5866
5867 APValue V;
5868 auto R = ::CheckConvertedConstantExpression(*this, From, T, V, CCE, true,
5869 /*Dest=*/nullptr);
5870 if (!R.isInvalid() && !R.get()->isValueDependent())
5871 Value = V.getInt();
5872 return R;
5873 }
5874
5875
5876 /// dropPointerConversions - If the given standard conversion sequence
5877 /// involves any pointer conversions, remove them. This may change
5878 /// the result type of the conversion sequence.
dropPointerConversion(StandardConversionSequence & SCS)5879 static void dropPointerConversion(StandardConversionSequence &SCS) {
5880 if (SCS.Second == ICK_Pointer_Conversion) {
5881 SCS.Second = ICK_Identity;
5882 SCS.Third = ICK_Identity;
5883 SCS.ToTypePtrs[2] = SCS.ToTypePtrs[1] = SCS.ToTypePtrs[0];
5884 }
5885 }
5886
5887 /// TryContextuallyConvertToObjCPointer - Attempt to contextually
5888 /// convert the expression From to an Objective-C pointer type.
5889 static ImplicitConversionSequence
TryContextuallyConvertToObjCPointer(Sema & S,Expr * From)5890 TryContextuallyConvertToObjCPointer(Sema &S, Expr *From) {
5891 // Do an implicit conversion to 'id'.
5892 QualType Ty = S.Context.getObjCIdType();
5893 ImplicitConversionSequence ICS
5894 = TryImplicitConversion(S, From, Ty,
5895 // FIXME: Are these flags correct?
5896 /*SuppressUserConversions=*/false,
5897 AllowedExplicit::Conversions,
5898 /*InOverloadResolution=*/false,
5899 /*CStyle=*/false,
5900 /*AllowObjCWritebackConversion=*/false,
5901 /*AllowObjCConversionOnExplicit=*/true);
5902
5903 // Strip off any final conversions to 'id'.
5904 switch (ICS.getKind()) {
5905 case ImplicitConversionSequence::BadConversion:
5906 case ImplicitConversionSequence::AmbiguousConversion:
5907 case ImplicitConversionSequence::EllipsisConversion:
5908 break;
5909
5910 case ImplicitConversionSequence::UserDefinedConversion:
5911 dropPointerConversion(ICS.UserDefined.After);
5912 break;
5913
5914 case ImplicitConversionSequence::StandardConversion:
5915 dropPointerConversion(ICS.Standard);
5916 break;
5917 }
5918
5919 return ICS;
5920 }
5921
5922 /// PerformContextuallyConvertToObjCPointer - Perform a contextual
5923 /// conversion of the expression From to an Objective-C pointer type.
5924 /// Returns a valid but null ExprResult if no conversion sequence exists.
PerformContextuallyConvertToObjCPointer(Expr * From)5925 ExprResult Sema::PerformContextuallyConvertToObjCPointer(Expr *From) {
5926 if (checkPlaceholderForOverload(*this, From))
5927 return ExprError();
5928
5929 QualType Ty = Context.getObjCIdType();
5930 ImplicitConversionSequence ICS =
5931 TryContextuallyConvertToObjCPointer(*this, From);
5932 if (!ICS.isBad())
5933 return PerformImplicitConversion(From, Ty, ICS, AA_Converting);
5934 return ExprResult();
5935 }
5936
5937 /// Determine whether the provided type is an integral type, or an enumeration
5938 /// type of a permitted flavor.
match(QualType T)5939 bool Sema::ICEConvertDiagnoser::match(QualType T) {
5940 return AllowScopedEnumerations ? T->isIntegralOrEnumerationType()
5941 : T->isIntegralOrUnscopedEnumerationType();
5942 }
5943
5944 static ExprResult
diagnoseAmbiguousConversion(Sema & SemaRef,SourceLocation Loc,Expr * From,Sema::ContextualImplicitConverter & Converter,QualType T,UnresolvedSetImpl & ViableConversions)5945 diagnoseAmbiguousConversion(Sema &SemaRef, SourceLocation Loc, Expr *From,
5946 Sema::ContextualImplicitConverter &Converter,
5947 QualType T, UnresolvedSetImpl &ViableConversions) {
5948
5949 if (Converter.Suppress)
5950 return ExprError();
5951
5952 Converter.diagnoseAmbiguous(SemaRef, Loc, T) << From->getSourceRange();
5953 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
5954 CXXConversionDecl *Conv =
5955 cast<CXXConversionDecl>(ViableConversions[I]->getUnderlyingDecl());
5956 QualType ConvTy = Conv->getConversionType().getNonReferenceType();
5957 Converter.noteAmbiguous(SemaRef, Conv, ConvTy);
5958 }
5959 return From;
5960 }
5961
5962 static bool
diagnoseNoViableConversion(Sema & SemaRef,SourceLocation Loc,Expr * & From,Sema::ContextualImplicitConverter & Converter,QualType T,bool HadMultipleCandidates,UnresolvedSetImpl & ExplicitConversions)5963 diagnoseNoViableConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
5964 Sema::ContextualImplicitConverter &Converter,
5965 QualType T, bool HadMultipleCandidates,
5966 UnresolvedSetImpl &ExplicitConversions) {
5967 if (ExplicitConversions.size() == 1 && !Converter.Suppress) {
5968 DeclAccessPair Found = ExplicitConversions[0];
5969 CXXConversionDecl *Conversion =
5970 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
5971
5972 // The user probably meant to invoke the given explicit
5973 // conversion; use it.
5974 QualType ConvTy = Conversion->getConversionType().getNonReferenceType();
5975 std::string TypeStr;
5976 ConvTy.getAsStringInternal(TypeStr, SemaRef.getPrintingPolicy());
5977
5978 Converter.diagnoseExplicitConv(SemaRef, Loc, T, ConvTy)
5979 << FixItHint::CreateInsertion(From->getBeginLoc(),
5980 "static_cast<" + TypeStr + ">(")
5981 << FixItHint::CreateInsertion(
5982 SemaRef.getLocForEndOfToken(From->getEndLoc()), ")");
5983 Converter.noteExplicitConv(SemaRef, Conversion, ConvTy);
5984
5985 // If we aren't in a SFINAE context, build a call to the
5986 // explicit conversion function.
5987 if (SemaRef.isSFINAEContext())
5988 return true;
5989
5990 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
5991 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
5992 HadMultipleCandidates);
5993 if (Result.isInvalid())
5994 return true;
5995 // Record usage of conversion in an implicit cast.
5996 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
5997 CK_UserDefinedConversion, Result.get(),
5998 nullptr, Result.get()->getValueKind(),
5999 SemaRef.CurFPFeatureOverrides());
6000 }
6001 return false;
6002 }
6003
recordConversion(Sema & SemaRef,SourceLocation Loc,Expr * & From,Sema::ContextualImplicitConverter & Converter,QualType T,bool HadMultipleCandidates,DeclAccessPair & Found)6004 static bool recordConversion(Sema &SemaRef, SourceLocation Loc, Expr *&From,
6005 Sema::ContextualImplicitConverter &Converter,
6006 QualType T, bool HadMultipleCandidates,
6007 DeclAccessPair &Found) {
6008 CXXConversionDecl *Conversion =
6009 cast<CXXConversionDecl>(Found->getUnderlyingDecl());
6010 SemaRef.CheckMemberOperatorAccess(From->getExprLoc(), From, nullptr, Found);
6011
6012 QualType ToType = Conversion->getConversionType().getNonReferenceType();
6013 if (!Converter.SuppressConversion) {
6014 if (SemaRef.isSFINAEContext())
6015 return true;
6016
6017 Converter.diagnoseConversion(SemaRef, Loc, T, ToType)
6018 << From->getSourceRange();
6019 }
6020
6021 ExprResult Result = SemaRef.BuildCXXMemberCallExpr(From, Found, Conversion,
6022 HadMultipleCandidates);
6023 if (Result.isInvalid())
6024 return true;
6025 // Record usage of conversion in an implicit cast.
6026 From = ImplicitCastExpr::Create(SemaRef.Context, Result.get()->getType(),
6027 CK_UserDefinedConversion, Result.get(),
6028 nullptr, Result.get()->getValueKind(),
6029 SemaRef.CurFPFeatureOverrides());
6030 return false;
6031 }
6032
finishContextualImplicitConversion(Sema & SemaRef,SourceLocation Loc,Expr * From,Sema::ContextualImplicitConverter & Converter)6033 static ExprResult finishContextualImplicitConversion(
6034 Sema &SemaRef, SourceLocation Loc, Expr *From,
6035 Sema::ContextualImplicitConverter &Converter) {
6036 if (!Converter.match(From->getType()) && !Converter.Suppress)
6037 Converter.diagnoseNoMatch(SemaRef, Loc, From->getType())
6038 << From->getSourceRange();
6039
6040 return SemaRef.DefaultLvalueConversion(From);
6041 }
6042
6043 static void
collectViableConversionCandidates(Sema & SemaRef,Expr * From,QualType ToType,UnresolvedSetImpl & ViableConversions,OverloadCandidateSet & CandidateSet)6044 collectViableConversionCandidates(Sema &SemaRef, Expr *From, QualType ToType,
6045 UnresolvedSetImpl &ViableConversions,
6046 OverloadCandidateSet &CandidateSet) {
6047 for (unsigned I = 0, N = ViableConversions.size(); I != N; ++I) {
6048 DeclAccessPair FoundDecl = ViableConversions[I];
6049 NamedDecl *D = FoundDecl.getDecl();
6050 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
6051 if (isa<UsingShadowDecl>(D))
6052 D = cast<UsingShadowDecl>(D)->getTargetDecl();
6053
6054 CXXConversionDecl *Conv;
6055 FunctionTemplateDecl *ConvTemplate;
6056 if ((ConvTemplate = dyn_cast<FunctionTemplateDecl>(D)))
6057 Conv = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
6058 else
6059 Conv = cast<CXXConversionDecl>(D);
6060
6061 if (ConvTemplate)
6062 SemaRef.AddTemplateConversionCandidate(
6063 ConvTemplate, FoundDecl, ActingContext, From, ToType, CandidateSet,
6064 /*AllowObjCConversionOnExplicit=*/false, /*AllowExplicit*/ true);
6065 else
6066 SemaRef.AddConversionCandidate(Conv, FoundDecl, ActingContext, From,
6067 ToType, CandidateSet,
6068 /*AllowObjCConversionOnExplicit=*/false,
6069 /*AllowExplicit*/ true);
6070 }
6071 }
6072
6073 /// Attempt to convert the given expression to a type which is accepted
6074 /// by the given converter.
6075 ///
6076 /// This routine will attempt to convert an expression of class type to a
6077 /// type accepted by the specified converter. In C++11 and before, the class
6078 /// must have a single non-explicit conversion function converting to a matching
6079 /// type. In C++1y, there can be multiple such conversion functions, but only
6080 /// one target type.
6081 ///
6082 /// \param Loc The source location of the construct that requires the
6083 /// conversion.
6084 ///
6085 /// \param From The expression we're converting from.
6086 ///
6087 /// \param Converter Used to control and diagnose the conversion process.
6088 ///
6089 /// \returns The expression, converted to an integral or enumeration type if
6090 /// successful.
PerformContextualImplicitConversion(SourceLocation Loc,Expr * From,ContextualImplicitConverter & Converter)6091 ExprResult Sema::PerformContextualImplicitConversion(
6092 SourceLocation Loc, Expr *From, ContextualImplicitConverter &Converter) {
6093 // We can't perform any more checking for type-dependent expressions.
6094 if (From->isTypeDependent())
6095 return From;
6096
6097 // Process placeholders immediately.
6098 if (From->hasPlaceholderType()) {
6099 ExprResult result = CheckPlaceholderExpr(From);
6100 if (result.isInvalid())
6101 return result;
6102 From = result.get();
6103 }
6104
6105 // If the expression already has a matching type, we're golden.
6106 QualType T = From->getType();
6107 if (Converter.match(T))
6108 return DefaultLvalueConversion(From);
6109
6110 // FIXME: Check for missing '()' if T is a function type?
6111
6112 // We can only perform contextual implicit conversions on objects of class
6113 // type.
6114 const RecordType *RecordTy = T->getAs<RecordType>();
6115 if (!RecordTy || !getLangOpts().CPlusPlus) {
6116 if (!Converter.Suppress)
6117 Converter.diagnoseNoMatch(*this, Loc, T) << From->getSourceRange();
6118 return From;
6119 }
6120
6121 // We must have a complete class type.
6122 struct TypeDiagnoserPartialDiag : TypeDiagnoser {
6123 ContextualImplicitConverter &Converter;
6124 Expr *From;
6125
6126 TypeDiagnoserPartialDiag(ContextualImplicitConverter &Converter, Expr *From)
6127 : Converter(Converter), From(From) {}
6128
6129 void diagnose(Sema &S, SourceLocation Loc, QualType T) override {
6130 Converter.diagnoseIncomplete(S, Loc, T) << From->getSourceRange();
6131 }
6132 } IncompleteDiagnoser(Converter, From);
6133
6134 if (Converter.Suppress ? !isCompleteType(Loc, T)
6135 : RequireCompleteType(Loc, T, IncompleteDiagnoser))
6136 return From;
6137
6138 // Look for a conversion to an integral or enumeration type.
6139 UnresolvedSet<4>
6140 ViableConversions; // These are *potentially* viable in C++1y.
6141 UnresolvedSet<4> ExplicitConversions;
6142 const auto &Conversions =
6143 cast<CXXRecordDecl>(RecordTy->getDecl())->getVisibleConversionFunctions();
6144
6145 bool HadMultipleCandidates =
6146 (std::distance(Conversions.begin(), Conversions.end()) > 1);
6147
6148 // To check that there is only one target type, in C++1y:
6149 QualType ToType;
6150 bool HasUniqueTargetType = true;
6151
6152 // Collect explicit or viable (potentially in C++1y) conversions.
6153 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
6154 NamedDecl *D = (*I)->getUnderlyingDecl();
6155 CXXConversionDecl *Conversion;
6156 FunctionTemplateDecl *ConvTemplate = dyn_cast<FunctionTemplateDecl>(D);
6157 if (ConvTemplate) {
6158 if (getLangOpts().CPlusPlus14)
6159 Conversion = cast<CXXConversionDecl>(ConvTemplate->getTemplatedDecl());
6160 else
6161 continue; // C++11 does not consider conversion operator templates(?).
6162 } else
6163 Conversion = cast<CXXConversionDecl>(D);
6164
6165 assert((!ConvTemplate || getLangOpts().CPlusPlus14) &&
6166 "Conversion operator templates are considered potentially "
6167 "viable in C++1y");
6168
6169 QualType CurToType = Conversion->getConversionType().getNonReferenceType();
6170 if (Converter.match(CurToType) || ConvTemplate) {
6171
6172 if (Conversion->isExplicit()) {
6173 // FIXME: For C++1y, do we need this restriction?
6174 // cf. diagnoseNoViableConversion()
6175 if (!ConvTemplate)
6176 ExplicitConversions.addDecl(I.getDecl(), I.getAccess());
6177 } else {
6178 if (!ConvTemplate && getLangOpts().CPlusPlus14) {
6179 if (ToType.isNull())
6180 ToType = CurToType.getUnqualifiedType();
6181 else if (HasUniqueTargetType &&
6182 (CurToType.getUnqualifiedType() != ToType))
6183 HasUniqueTargetType = false;
6184 }
6185 ViableConversions.addDecl(I.getDecl(), I.getAccess());
6186 }
6187 }
6188 }
6189
6190 if (getLangOpts().CPlusPlus14) {
6191 // C++1y [conv]p6:
6192 // ... An expression e of class type E appearing in such a context
6193 // is said to be contextually implicitly converted to a specified
6194 // type T and is well-formed if and only if e can be implicitly
6195 // converted to a type T that is determined as follows: E is searched
6196 // for conversion functions whose return type is cv T or reference to
6197 // cv T such that T is allowed by the context. There shall be
6198 // exactly one such T.
6199
6200 // If no unique T is found:
6201 if (ToType.isNull()) {
6202 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6203 HadMultipleCandidates,
6204 ExplicitConversions))
6205 return ExprError();
6206 return finishContextualImplicitConversion(*this, Loc, From, Converter);
6207 }
6208
6209 // If more than one unique Ts are found:
6210 if (!HasUniqueTargetType)
6211 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6212 ViableConversions);
6213
6214 // If one unique T is found:
6215 // First, build a candidate set from the previously recorded
6216 // potentially viable conversions.
6217 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Normal);
6218 collectViableConversionCandidates(*this, From, ToType, ViableConversions,
6219 CandidateSet);
6220
6221 // Then, perform overload resolution over the candidate set.
6222 OverloadCandidateSet::iterator Best;
6223 switch (CandidateSet.BestViableFunction(*this, Loc, Best)) {
6224 case OR_Success: {
6225 // Apply this conversion.
6226 DeclAccessPair Found =
6227 DeclAccessPair::make(Best->Function, Best->FoundDecl.getAccess());
6228 if (recordConversion(*this, Loc, From, Converter, T,
6229 HadMultipleCandidates, Found))
6230 return ExprError();
6231 break;
6232 }
6233 case OR_Ambiguous:
6234 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6235 ViableConversions);
6236 case OR_No_Viable_Function:
6237 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6238 HadMultipleCandidates,
6239 ExplicitConversions))
6240 return ExprError();
6241 LLVM_FALLTHROUGH;
6242 case OR_Deleted:
6243 // We'll complain below about a non-integral condition type.
6244 break;
6245 }
6246 } else {
6247 switch (ViableConversions.size()) {
6248 case 0: {
6249 if (diagnoseNoViableConversion(*this, Loc, From, Converter, T,
6250 HadMultipleCandidates,
6251 ExplicitConversions))
6252 return ExprError();
6253
6254 // We'll complain below about a non-integral condition type.
6255 break;
6256 }
6257 case 1: {
6258 // Apply this conversion.
6259 DeclAccessPair Found = ViableConversions[0];
6260 if (recordConversion(*this, Loc, From, Converter, T,
6261 HadMultipleCandidates, Found))
6262 return ExprError();
6263 break;
6264 }
6265 default:
6266 return diagnoseAmbiguousConversion(*this, Loc, From, Converter, T,
6267 ViableConversions);
6268 }
6269 }
6270
6271 return finishContextualImplicitConversion(*this, Loc, From, Converter);
6272 }
6273
6274 /// IsAcceptableNonMemberOperatorCandidate - Determine whether Fn is
6275 /// an acceptable non-member overloaded operator for a call whose
6276 /// arguments have types T1 (and, if non-empty, T2). This routine
6277 /// implements the check in C++ [over.match.oper]p3b2 concerning
6278 /// enumeration types.
IsAcceptableNonMemberOperatorCandidate(ASTContext & Context,FunctionDecl * Fn,ArrayRef<Expr * > Args)6279 static bool IsAcceptableNonMemberOperatorCandidate(ASTContext &Context,
6280 FunctionDecl *Fn,
6281 ArrayRef<Expr *> Args) {
6282 QualType T1 = Args[0]->getType();
6283 QualType T2 = Args.size() > 1 ? Args[1]->getType() : QualType();
6284
6285 if (T1->isDependentType() || (!T2.isNull() && T2->isDependentType()))
6286 return true;
6287
6288 if (T1->isRecordType() || (!T2.isNull() && T2->isRecordType()))
6289 return true;
6290
6291 const auto *Proto = Fn->getType()->castAs<FunctionProtoType>();
6292 if (Proto->getNumParams() < 1)
6293 return false;
6294
6295 if (T1->isEnumeralType()) {
6296 QualType ArgType = Proto->getParamType(0).getNonReferenceType();
6297 if (Context.hasSameUnqualifiedType(T1, ArgType))
6298 return true;
6299 }
6300
6301 if (Proto->getNumParams() < 2)
6302 return false;
6303
6304 if (!T2.isNull() && T2->isEnumeralType()) {
6305 QualType ArgType = Proto->getParamType(1).getNonReferenceType();
6306 if (Context.hasSameUnqualifiedType(T2, ArgType))
6307 return true;
6308 }
6309
6310 return false;
6311 }
6312
6313 /// AddOverloadCandidate - Adds the given function to the set of
6314 /// candidate functions, using the given function call arguments. If
6315 /// @p SuppressUserConversions, then don't allow user-defined
6316 /// conversions via constructors or conversion operators.
6317 ///
6318 /// \param PartialOverloading true if we are performing "partial" overloading
6319 /// based on an incomplete set of function arguments. This feature is used by
6320 /// code completion.
AddOverloadCandidate(FunctionDecl * Function,DeclAccessPair FoundDecl,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool SuppressUserConversions,bool PartialOverloading,bool AllowExplicit,bool AllowExplicitConversions,ADLCallKind IsADLCandidate,ConversionSequenceList EarlyConversions,OverloadCandidateParamOrder PO)6321 void Sema::AddOverloadCandidate(
6322 FunctionDecl *Function, DeclAccessPair FoundDecl, ArrayRef<Expr *> Args,
6323 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
6324 bool PartialOverloading, bool AllowExplicit, bool AllowExplicitConversions,
6325 ADLCallKind IsADLCandidate, ConversionSequenceList EarlyConversions,
6326 OverloadCandidateParamOrder PO) {
6327 const FunctionProtoType *Proto
6328 = dyn_cast<FunctionProtoType>(Function->getType()->getAs<FunctionType>());
6329 assert(Proto && "Functions without a prototype cannot be overloaded");
6330 assert(!Function->getDescribedFunctionTemplate() &&
6331 "Use AddTemplateOverloadCandidate for function templates");
6332
6333 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
6334 if (!isa<CXXConstructorDecl>(Method)) {
6335 // If we get here, it's because we're calling a member function
6336 // that is named without a member access expression (e.g.,
6337 // "this->f") that was either written explicitly or created
6338 // implicitly. This can happen with a qualified call to a member
6339 // function, e.g., X::f(). We use an empty type for the implied
6340 // object argument (C++ [over.call.func]p3), and the acting context
6341 // is irrelevant.
6342 AddMethodCandidate(Method, FoundDecl, Method->getParent(), QualType(),
6343 Expr::Classification::makeSimpleLValue(), Args,
6344 CandidateSet, SuppressUserConversions,
6345 PartialOverloading, EarlyConversions, PO);
6346 return;
6347 }
6348 // We treat a constructor like a non-member function, since its object
6349 // argument doesn't participate in overload resolution.
6350 }
6351
6352 if (!CandidateSet.isNewCandidate(Function, PO))
6353 return;
6354
6355 // C++11 [class.copy]p11: [DR1402]
6356 // A defaulted move constructor that is defined as deleted is ignored by
6357 // overload resolution.
6358 CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(Function);
6359 if (Constructor && Constructor->isDefaulted() && Constructor->isDeleted() &&
6360 Constructor->isMoveConstructor())
6361 return;
6362
6363 // Overload resolution is always an unevaluated context.
6364 EnterExpressionEvaluationContext Unevaluated(
6365 *this, Sema::ExpressionEvaluationContext::Unevaluated);
6366
6367 // C++ [over.match.oper]p3:
6368 // if no operand has a class type, only those non-member functions in the
6369 // lookup set that have a first parameter of type T1 or "reference to
6370 // (possibly cv-qualified) T1", when T1 is an enumeration type, or (if there
6371 // is a right operand) a second parameter of type T2 or "reference to
6372 // (possibly cv-qualified) T2", when T2 is an enumeration type, are
6373 // candidate functions.
6374 if (CandidateSet.getKind() == OverloadCandidateSet::CSK_Operator &&
6375 !IsAcceptableNonMemberOperatorCandidate(Context, Function, Args))
6376 return;
6377
6378 // Add this candidate
6379 OverloadCandidate &Candidate =
6380 CandidateSet.addCandidate(Args.size(), EarlyConversions);
6381 Candidate.FoundDecl = FoundDecl;
6382 Candidate.Function = Function;
6383 Candidate.Viable = true;
6384 Candidate.RewriteKind =
6385 CandidateSet.getRewriteInfo().getRewriteKind(Function, PO);
6386 Candidate.IsSurrogate = false;
6387 Candidate.IsADLCandidate = IsADLCandidate;
6388 Candidate.IgnoreObjectArgument = false;
6389 Candidate.ExplicitCallArguments = Args.size();
6390
6391 // Explicit functions are not actually candidates at all if we're not
6392 // allowing them in this context, but keep them around so we can point
6393 // to them in diagnostics.
6394 if (!AllowExplicit && ExplicitSpecifier::getFromDecl(Function).isExplicit()) {
6395 Candidate.Viable = false;
6396 Candidate.FailureKind = ovl_fail_explicit;
6397 return;
6398 }
6399
6400 if (Function->isMultiVersion() && Function->hasAttr<TargetAttr>() &&
6401 !Function->getAttr<TargetAttr>()->isDefaultVersion()) {
6402 Candidate.Viable = false;
6403 Candidate.FailureKind = ovl_non_default_multiversion_function;
6404 return;
6405 }
6406
6407 if (Constructor) {
6408 // C++ [class.copy]p3:
6409 // A member function template is never instantiated to perform the copy
6410 // of a class object to an object of its class type.
6411 QualType ClassType = Context.getTypeDeclType(Constructor->getParent());
6412 if (Args.size() == 1 && Constructor->isSpecializationCopyingObject() &&
6413 (Context.hasSameUnqualifiedType(ClassType, Args[0]->getType()) ||
6414 IsDerivedFrom(Args[0]->getBeginLoc(), Args[0]->getType(),
6415 ClassType))) {
6416 Candidate.Viable = false;
6417 Candidate.FailureKind = ovl_fail_illegal_constructor;
6418 return;
6419 }
6420
6421 // C++ [over.match.funcs]p8: (proposed DR resolution)
6422 // A constructor inherited from class type C that has a first parameter
6423 // of type "reference to P" (including such a constructor instantiated
6424 // from a template) is excluded from the set of candidate functions when
6425 // constructing an object of type cv D if the argument list has exactly
6426 // one argument and D is reference-related to P and P is reference-related
6427 // to C.
6428 auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl.getDecl());
6429 if (Shadow && Args.size() == 1 && Constructor->getNumParams() >= 1 &&
6430 Constructor->getParamDecl(0)->getType()->isReferenceType()) {
6431 QualType P = Constructor->getParamDecl(0)->getType()->getPointeeType();
6432 QualType C = Context.getRecordType(Constructor->getParent());
6433 QualType D = Context.getRecordType(Shadow->getParent());
6434 SourceLocation Loc = Args.front()->getExprLoc();
6435 if ((Context.hasSameUnqualifiedType(P, C) || IsDerivedFrom(Loc, P, C)) &&
6436 (Context.hasSameUnqualifiedType(D, P) || IsDerivedFrom(Loc, D, P))) {
6437 Candidate.Viable = false;
6438 Candidate.FailureKind = ovl_fail_inhctor_slice;
6439 return;
6440 }
6441 }
6442
6443 // Check that the constructor is capable of constructing an object in the
6444 // destination address space.
6445 if (!Qualifiers::isAddressSpaceSupersetOf(
6446 Constructor->getMethodQualifiers().getAddressSpace(),
6447 CandidateSet.getDestAS())) {
6448 Candidate.Viable = false;
6449 Candidate.FailureKind = ovl_fail_object_addrspace_mismatch;
6450 }
6451 }
6452
6453 unsigned NumParams = Proto->getNumParams();
6454
6455 // (C++ 13.3.2p2): A candidate function having fewer than m
6456 // parameters is viable only if it has an ellipsis in its parameter
6457 // list (8.3.5).
6458 if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
6459 !Proto->isVariadic()) {
6460 Candidate.Viable = false;
6461 Candidate.FailureKind = ovl_fail_too_many_arguments;
6462 return;
6463 }
6464
6465 // (C++ 13.3.2p2): A candidate function having more than m parameters
6466 // is viable only if the (m+1)st parameter has a default argument
6467 // (8.3.6). For the purposes of overload resolution, the
6468 // parameter list is truncated on the right, so that there are
6469 // exactly m parameters.
6470 unsigned MinRequiredArgs = Function->getMinRequiredArguments();
6471 if (Args.size() < MinRequiredArgs && !PartialOverloading) {
6472 // Not enough arguments.
6473 Candidate.Viable = false;
6474 Candidate.FailureKind = ovl_fail_too_few_arguments;
6475 return;
6476 }
6477
6478 // (CUDA B.1): Check for invalid calls between targets.
6479 if (getLangOpts().CUDA)
6480 if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
6481 // Skip the check for callers that are implicit members, because in this
6482 // case we may not yet know what the member's target is; the target is
6483 // inferred for the member automatically, based on the bases and fields of
6484 // the class.
6485 if (!Caller->isImplicit() && !IsAllowedCUDACall(Caller, Function)) {
6486 Candidate.Viable = false;
6487 Candidate.FailureKind = ovl_fail_bad_target;
6488 return;
6489 }
6490
6491 if (Function->getTrailingRequiresClause()) {
6492 ConstraintSatisfaction Satisfaction;
6493 if (CheckFunctionConstraints(Function, Satisfaction) ||
6494 !Satisfaction.IsSatisfied) {
6495 Candidate.Viable = false;
6496 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
6497 return;
6498 }
6499 }
6500
6501 // Determine the implicit conversion sequences for each of the
6502 // arguments.
6503 for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
6504 unsigned ConvIdx =
6505 PO == OverloadCandidateParamOrder::Reversed ? 1 - ArgIdx : ArgIdx;
6506 if (Candidate.Conversions[ConvIdx].isInitialized()) {
6507 // We already formed a conversion sequence for this parameter during
6508 // template argument deduction.
6509 } else if (ArgIdx < NumParams) {
6510 // (C++ 13.3.2p3): for F to be a viable function, there shall
6511 // exist for each argument an implicit conversion sequence
6512 // (13.3.3.1) that converts that argument to the corresponding
6513 // parameter of F.
6514 QualType ParamType = Proto->getParamType(ArgIdx);
6515 Candidate.Conversions[ConvIdx] = TryCopyInitialization(
6516 *this, Args[ArgIdx], ParamType, SuppressUserConversions,
6517 /*InOverloadResolution=*/true,
6518 /*AllowObjCWritebackConversion=*/
6519 getLangOpts().ObjCAutoRefCount, AllowExplicitConversions);
6520 if (Candidate.Conversions[ConvIdx].isBad()) {
6521 Candidate.Viable = false;
6522 Candidate.FailureKind = ovl_fail_bad_conversion;
6523 return;
6524 }
6525 } else {
6526 // (C++ 13.3.2p2): For the purposes of overload resolution, any
6527 // argument for which there is no corresponding parameter is
6528 // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
6529 Candidate.Conversions[ConvIdx].setEllipsis();
6530 }
6531 }
6532
6533 if (EnableIfAttr *FailedAttr =
6534 CheckEnableIf(Function, CandidateSet.getLocation(), Args)) {
6535 Candidate.Viable = false;
6536 Candidate.FailureKind = ovl_fail_enable_if;
6537 Candidate.DeductionFailure.Data = FailedAttr;
6538 return;
6539 }
6540 }
6541
6542 ObjCMethodDecl *
SelectBestMethod(Selector Sel,MultiExprArg Args,bool IsInstance,SmallVectorImpl<ObjCMethodDecl * > & Methods)6543 Sema::SelectBestMethod(Selector Sel, MultiExprArg Args, bool IsInstance,
6544 SmallVectorImpl<ObjCMethodDecl *> &Methods) {
6545 if (Methods.size() <= 1)
6546 return nullptr;
6547
6548 for (unsigned b = 0, e = Methods.size(); b < e; b++) {
6549 bool Match = true;
6550 ObjCMethodDecl *Method = Methods[b];
6551 unsigned NumNamedArgs = Sel.getNumArgs();
6552 // Method might have more arguments than selector indicates. This is due
6553 // to addition of c-style arguments in method.
6554 if (Method->param_size() > NumNamedArgs)
6555 NumNamedArgs = Method->param_size();
6556 if (Args.size() < NumNamedArgs)
6557 continue;
6558
6559 for (unsigned i = 0; i < NumNamedArgs; i++) {
6560 // We can't do any type-checking on a type-dependent argument.
6561 if (Args[i]->isTypeDependent()) {
6562 Match = false;
6563 break;
6564 }
6565
6566 ParmVarDecl *param = Method->parameters()[i];
6567 Expr *argExpr = Args[i];
6568 assert(argExpr && "SelectBestMethod(): missing expression");
6569
6570 // Strip the unbridged-cast placeholder expression off unless it's
6571 // a consumed argument.
6572 if (argExpr->hasPlaceholderType(BuiltinType::ARCUnbridgedCast) &&
6573 !param->hasAttr<CFConsumedAttr>())
6574 argExpr = stripARCUnbridgedCast(argExpr);
6575
6576 // If the parameter is __unknown_anytype, move on to the next method.
6577 if (param->getType() == Context.UnknownAnyTy) {
6578 Match = false;
6579 break;
6580 }
6581
6582 ImplicitConversionSequence ConversionState
6583 = TryCopyInitialization(*this, argExpr, param->getType(),
6584 /*SuppressUserConversions*/false,
6585 /*InOverloadResolution=*/true,
6586 /*AllowObjCWritebackConversion=*/
6587 getLangOpts().ObjCAutoRefCount,
6588 /*AllowExplicit*/false);
6589 // This function looks for a reasonably-exact match, so we consider
6590 // incompatible pointer conversions to be a failure here.
6591 if (ConversionState.isBad() ||
6592 (ConversionState.isStandard() &&
6593 ConversionState.Standard.Second ==
6594 ICK_Incompatible_Pointer_Conversion)) {
6595 Match = false;
6596 break;
6597 }
6598 }
6599 // Promote additional arguments to variadic methods.
6600 if (Match && Method->isVariadic()) {
6601 for (unsigned i = NumNamedArgs, e = Args.size(); i < e; ++i) {
6602 if (Args[i]->isTypeDependent()) {
6603 Match = false;
6604 break;
6605 }
6606 ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
6607 nullptr);
6608 if (Arg.isInvalid()) {
6609 Match = false;
6610 break;
6611 }
6612 }
6613 } else {
6614 // Check for extra arguments to non-variadic methods.
6615 if (Args.size() != NumNamedArgs)
6616 Match = false;
6617 else if (Match && NumNamedArgs == 0 && Methods.size() > 1) {
6618 // Special case when selectors have no argument. In this case, select
6619 // one with the most general result type of 'id'.
6620 for (unsigned b = 0, e = Methods.size(); b < e; b++) {
6621 QualType ReturnT = Methods[b]->getReturnType();
6622 if (ReturnT->isObjCIdType())
6623 return Methods[b];
6624 }
6625 }
6626 }
6627
6628 if (Match)
6629 return Method;
6630 }
6631 return nullptr;
6632 }
6633
convertArgsForAvailabilityChecks(Sema & S,FunctionDecl * Function,Expr * ThisArg,SourceLocation CallLoc,ArrayRef<Expr * > Args,Sema::SFINAETrap & Trap,bool MissingImplicitThis,Expr * & ConvertedThis,SmallVectorImpl<Expr * > & ConvertedArgs)6634 static bool convertArgsForAvailabilityChecks(
6635 Sema &S, FunctionDecl *Function, Expr *ThisArg, SourceLocation CallLoc,
6636 ArrayRef<Expr *> Args, Sema::SFINAETrap &Trap, bool MissingImplicitThis,
6637 Expr *&ConvertedThis, SmallVectorImpl<Expr *> &ConvertedArgs) {
6638 if (ThisArg) {
6639 CXXMethodDecl *Method = cast<CXXMethodDecl>(Function);
6640 assert(!isa<CXXConstructorDecl>(Method) &&
6641 "Shouldn't have `this` for ctors!");
6642 assert(!Method->isStatic() && "Shouldn't have `this` for static methods!");
6643 ExprResult R = S.PerformObjectArgumentInitialization(
6644 ThisArg, /*Qualifier=*/nullptr, Method, Method);
6645 if (R.isInvalid())
6646 return false;
6647 ConvertedThis = R.get();
6648 } else {
6649 if (auto *MD = dyn_cast<CXXMethodDecl>(Function)) {
6650 (void)MD;
6651 assert((MissingImplicitThis || MD->isStatic() ||
6652 isa<CXXConstructorDecl>(MD)) &&
6653 "Expected `this` for non-ctor instance methods");
6654 }
6655 ConvertedThis = nullptr;
6656 }
6657
6658 // Ignore any variadic arguments. Converting them is pointless, since the
6659 // user can't refer to them in the function condition.
6660 unsigned ArgSizeNoVarargs = std::min(Function->param_size(), Args.size());
6661
6662 // Convert the arguments.
6663 for (unsigned I = 0; I != ArgSizeNoVarargs; ++I) {
6664 ExprResult R;
6665 R = S.PerformCopyInitialization(InitializedEntity::InitializeParameter(
6666 S.Context, Function->getParamDecl(I)),
6667 SourceLocation(), Args[I]);
6668
6669 if (R.isInvalid())
6670 return false;
6671
6672 ConvertedArgs.push_back(R.get());
6673 }
6674
6675 if (Trap.hasErrorOccurred())
6676 return false;
6677
6678 // Push default arguments if needed.
6679 if (!Function->isVariadic() && Args.size() < Function->getNumParams()) {
6680 for (unsigned i = Args.size(), e = Function->getNumParams(); i != e; ++i) {
6681 ParmVarDecl *P = Function->getParamDecl(i);
6682 if (!P->hasDefaultArg())
6683 return false;
6684 ExprResult R = S.BuildCXXDefaultArgExpr(CallLoc, Function, P);
6685 if (R.isInvalid())
6686 return false;
6687 ConvertedArgs.push_back(R.get());
6688 }
6689
6690 if (Trap.hasErrorOccurred())
6691 return false;
6692 }
6693 return true;
6694 }
6695
CheckEnableIf(FunctionDecl * Function,SourceLocation CallLoc,ArrayRef<Expr * > Args,bool MissingImplicitThis)6696 EnableIfAttr *Sema::CheckEnableIf(FunctionDecl *Function,
6697 SourceLocation CallLoc,
6698 ArrayRef<Expr *> Args,
6699 bool MissingImplicitThis) {
6700 auto EnableIfAttrs = Function->specific_attrs<EnableIfAttr>();
6701 if (EnableIfAttrs.begin() == EnableIfAttrs.end())
6702 return nullptr;
6703
6704 SFINAETrap Trap(*this);
6705 SmallVector<Expr *, 16> ConvertedArgs;
6706 // FIXME: We should look into making enable_if late-parsed.
6707 Expr *DiscardedThis;
6708 if (!convertArgsForAvailabilityChecks(
6709 *this, Function, /*ThisArg=*/nullptr, CallLoc, Args, Trap,
6710 /*MissingImplicitThis=*/true, DiscardedThis, ConvertedArgs))
6711 return *EnableIfAttrs.begin();
6712
6713 for (auto *EIA : EnableIfAttrs) {
6714 APValue Result;
6715 // FIXME: This doesn't consider value-dependent cases, because doing so is
6716 // very difficult. Ideally, we should handle them more gracefully.
6717 if (EIA->getCond()->isValueDependent() ||
6718 !EIA->getCond()->EvaluateWithSubstitution(
6719 Result, Context, Function, llvm::makeArrayRef(ConvertedArgs)))
6720 return EIA;
6721
6722 if (!Result.isInt() || !Result.getInt().getBoolValue())
6723 return EIA;
6724 }
6725 return nullptr;
6726 }
6727
6728 template <typename CheckFn>
diagnoseDiagnoseIfAttrsWith(Sema & S,const NamedDecl * ND,bool ArgDependent,SourceLocation Loc,CheckFn && IsSuccessful)6729 static bool diagnoseDiagnoseIfAttrsWith(Sema &S, const NamedDecl *ND,
6730 bool ArgDependent, SourceLocation Loc,
6731 CheckFn &&IsSuccessful) {
6732 SmallVector<const DiagnoseIfAttr *, 8> Attrs;
6733 for (const auto *DIA : ND->specific_attrs<DiagnoseIfAttr>()) {
6734 if (ArgDependent == DIA->getArgDependent())
6735 Attrs.push_back(DIA);
6736 }
6737
6738 // Common case: No diagnose_if attributes, so we can quit early.
6739 if (Attrs.empty())
6740 return false;
6741
6742 auto WarningBegin = std::stable_partition(
6743 Attrs.begin(), Attrs.end(),
6744 [](const DiagnoseIfAttr *DIA) { return DIA->isError(); });
6745
6746 // Note that diagnose_if attributes are late-parsed, so they appear in the
6747 // correct order (unlike enable_if attributes).
6748 auto ErrAttr = llvm::find_if(llvm::make_range(Attrs.begin(), WarningBegin),
6749 IsSuccessful);
6750 if (ErrAttr != WarningBegin) {
6751 const DiagnoseIfAttr *DIA = *ErrAttr;
6752 S.Diag(Loc, diag::err_diagnose_if_succeeded) << DIA->getMessage();
6753 S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
6754 << DIA->getParent() << DIA->getCond()->getSourceRange();
6755 return true;
6756 }
6757
6758 for (const auto *DIA : llvm::make_range(WarningBegin, Attrs.end()))
6759 if (IsSuccessful(DIA)) {
6760 S.Diag(Loc, diag::warn_diagnose_if_succeeded) << DIA->getMessage();
6761 S.Diag(DIA->getLocation(), diag::note_from_diagnose_if)
6762 << DIA->getParent() << DIA->getCond()->getSourceRange();
6763 }
6764
6765 return false;
6766 }
6767
diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl * Function,const Expr * ThisArg,ArrayRef<const Expr * > Args,SourceLocation Loc)6768 bool Sema::diagnoseArgDependentDiagnoseIfAttrs(const FunctionDecl *Function,
6769 const Expr *ThisArg,
6770 ArrayRef<const Expr *> Args,
6771 SourceLocation Loc) {
6772 return diagnoseDiagnoseIfAttrsWith(
6773 *this, Function, /*ArgDependent=*/true, Loc,
6774 [&](const DiagnoseIfAttr *DIA) {
6775 APValue Result;
6776 // It's sane to use the same Args for any redecl of this function, since
6777 // EvaluateWithSubstitution only cares about the position of each
6778 // argument in the arg list, not the ParmVarDecl* it maps to.
6779 if (!DIA->getCond()->EvaluateWithSubstitution(
6780 Result, Context, cast<FunctionDecl>(DIA->getParent()), Args, ThisArg))
6781 return false;
6782 return Result.isInt() && Result.getInt().getBoolValue();
6783 });
6784 }
6785
diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl * ND,SourceLocation Loc)6786 bool Sema::diagnoseArgIndependentDiagnoseIfAttrs(const NamedDecl *ND,
6787 SourceLocation Loc) {
6788 return diagnoseDiagnoseIfAttrsWith(
6789 *this, ND, /*ArgDependent=*/false, Loc,
6790 [&](const DiagnoseIfAttr *DIA) {
6791 bool Result;
6792 return DIA->getCond()->EvaluateAsBooleanCondition(Result, Context) &&
6793 Result;
6794 });
6795 }
6796
6797 /// Add all of the function declarations in the given function set to
6798 /// the overload candidate set.
AddFunctionCandidates(const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,TemplateArgumentListInfo * ExplicitTemplateArgs,bool SuppressUserConversions,bool PartialOverloading,bool FirstArgumentIsBase)6799 void Sema::AddFunctionCandidates(const UnresolvedSetImpl &Fns,
6800 ArrayRef<Expr *> Args,
6801 OverloadCandidateSet &CandidateSet,
6802 TemplateArgumentListInfo *ExplicitTemplateArgs,
6803 bool SuppressUserConversions,
6804 bool PartialOverloading,
6805 bool FirstArgumentIsBase) {
6806 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
6807 NamedDecl *D = F.getDecl()->getUnderlyingDecl();
6808 ArrayRef<Expr *> FunctionArgs = Args;
6809
6810 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
6811 FunctionDecl *FD =
6812 FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
6813
6814 if (isa<CXXMethodDecl>(FD) && !cast<CXXMethodDecl>(FD)->isStatic()) {
6815 QualType ObjectType;
6816 Expr::Classification ObjectClassification;
6817 if (Args.size() > 0) {
6818 if (Expr *E = Args[0]) {
6819 // Use the explicit base to restrict the lookup:
6820 ObjectType = E->getType();
6821 // Pointers in the object arguments are implicitly dereferenced, so we
6822 // always classify them as l-values.
6823 if (!ObjectType.isNull() && ObjectType->isPointerType())
6824 ObjectClassification = Expr::Classification::makeSimpleLValue();
6825 else
6826 ObjectClassification = E->Classify(Context);
6827 } // .. else there is an implicit base.
6828 FunctionArgs = Args.slice(1);
6829 }
6830 if (FunTmpl) {
6831 AddMethodTemplateCandidate(
6832 FunTmpl, F.getPair(),
6833 cast<CXXRecordDecl>(FunTmpl->getDeclContext()),
6834 ExplicitTemplateArgs, ObjectType, ObjectClassification,
6835 FunctionArgs, CandidateSet, SuppressUserConversions,
6836 PartialOverloading);
6837 } else {
6838 AddMethodCandidate(cast<CXXMethodDecl>(FD), F.getPair(),
6839 cast<CXXMethodDecl>(FD)->getParent(), ObjectType,
6840 ObjectClassification, FunctionArgs, CandidateSet,
6841 SuppressUserConversions, PartialOverloading);
6842 }
6843 } else {
6844 // This branch handles both standalone functions and static methods.
6845
6846 // Slice the first argument (which is the base) when we access
6847 // static method as non-static.
6848 if (Args.size() > 0 &&
6849 (!Args[0] || (FirstArgumentIsBase && isa<CXXMethodDecl>(FD) &&
6850 !isa<CXXConstructorDecl>(FD)))) {
6851 assert(cast<CXXMethodDecl>(FD)->isStatic());
6852 FunctionArgs = Args.slice(1);
6853 }
6854 if (FunTmpl) {
6855 AddTemplateOverloadCandidate(FunTmpl, F.getPair(),
6856 ExplicitTemplateArgs, FunctionArgs,
6857 CandidateSet, SuppressUserConversions,
6858 PartialOverloading);
6859 } else {
6860 AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet,
6861 SuppressUserConversions, PartialOverloading);
6862 }
6863 }
6864 }
6865 }
6866
6867 /// AddMethodCandidate - Adds a named decl (which is some kind of
6868 /// method) as a method candidate to the given overload set.
AddMethodCandidate(DeclAccessPair FoundDecl,QualType ObjectType,Expr::Classification ObjectClassification,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool SuppressUserConversions,OverloadCandidateParamOrder PO)6869 void Sema::AddMethodCandidate(DeclAccessPair FoundDecl, QualType ObjectType,
6870 Expr::Classification ObjectClassification,
6871 ArrayRef<Expr *> Args,
6872 OverloadCandidateSet &CandidateSet,
6873 bool SuppressUserConversions,
6874 OverloadCandidateParamOrder PO) {
6875 NamedDecl *Decl = FoundDecl.getDecl();
6876 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(Decl->getDeclContext());
6877
6878 if (isa<UsingShadowDecl>(Decl))
6879 Decl = cast<UsingShadowDecl>(Decl)->getTargetDecl();
6880
6881 if (FunctionTemplateDecl *TD = dyn_cast<FunctionTemplateDecl>(Decl)) {
6882 assert(isa<CXXMethodDecl>(TD->getTemplatedDecl()) &&
6883 "Expected a member function template");
6884 AddMethodTemplateCandidate(TD, FoundDecl, ActingContext,
6885 /*ExplicitArgs*/ nullptr, ObjectType,
6886 ObjectClassification, Args, CandidateSet,
6887 SuppressUserConversions, false, PO);
6888 } else {
6889 AddMethodCandidate(cast<CXXMethodDecl>(Decl), FoundDecl, ActingContext,
6890 ObjectType, ObjectClassification, Args, CandidateSet,
6891 SuppressUserConversions, false, None, PO);
6892 }
6893 }
6894
6895 /// AddMethodCandidate - Adds the given C++ member function to the set
6896 /// of candidate functions, using the given function call arguments
6897 /// and the object argument (@c Object). For example, in a call
6898 /// @c o.f(a1,a2), @c Object will contain @c o and @c Args will contain
6899 /// both @c a1 and @c a2. If @p SuppressUserConversions, then don't
6900 /// allow user-defined conversions via constructors or conversion
6901 /// operators.
6902 void
AddMethodCandidate(CXXMethodDecl * Method,DeclAccessPair FoundDecl,CXXRecordDecl * ActingContext,QualType ObjectType,Expr::Classification ObjectClassification,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool SuppressUserConversions,bool PartialOverloading,ConversionSequenceList EarlyConversions,OverloadCandidateParamOrder PO)6903 Sema::AddMethodCandidate(CXXMethodDecl *Method, DeclAccessPair FoundDecl,
6904 CXXRecordDecl *ActingContext, QualType ObjectType,
6905 Expr::Classification ObjectClassification,
6906 ArrayRef<Expr *> Args,
6907 OverloadCandidateSet &CandidateSet,
6908 bool SuppressUserConversions,
6909 bool PartialOverloading,
6910 ConversionSequenceList EarlyConversions,
6911 OverloadCandidateParamOrder PO) {
6912 const FunctionProtoType *Proto
6913 = dyn_cast<FunctionProtoType>(Method->getType()->getAs<FunctionType>());
6914 assert(Proto && "Methods without a prototype cannot be overloaded");
6915 assert(!isa<CXXConstructorDecl>(Method) &&
6916 "Use AddOverloadCandidate for constructors");
6917
6918 if (!CandidateSet.isNewCandidate(Method, PO))
6919 return;
6920
6921 // C++11 [class.copy]p23: [DR1402]
6922 // A defaulted move assignment operator that is defined as deleted is
6923 // ignored by overload resolution.
6924 if (Method->isDefaulted() && Method->isDeleted() &&
6925 Method->isMoveAssignmentOperator())
6926 return;
6927
6928 // Overload resolution is always an unevaluated context.
6929 EnterExpressionEvaluationContext Unevaluated(
6930 *this, Sema::ExpressionEvaluationContext::Unevaluated);
6931
6932 // Add this candidate
6933 OverloadCandidate &Candidate =
6934 CandidateSet.addCandidate(Args.size() + 1, EarlyConversions);
6935 Candidate.FoundDecl = FoundDecl;
6936 Candidate.Function = Method;
6937 Candidate.RewriteKind =
6938 CandidateSet.getRewriteInfo().getRewriteKind(Method, PO);
6939 Candidate.IsSurrogate = false;
6940 Candidate.IgnoreObjectArgument = false;
6941 Candidate.ExplicitCallArguments = Args.size();
6942
6943 unsigned NumParams = Proto->getNumParams();
6944
6945 // (C++ 13.3.2p2): A candidate function having fewer than m
6946 // parameters is viable only if it has an ellipsis in its parameter
6947 // list (8.3.5).
6948 if (TooManyArguments(NumParams, Args.size(), PartialOverloading) &&
6949 !Proto->isVariadic()) {
6950 Candidate.Viable = false;
6951 Candidate.FailureKind = ovl_fail_too_many_arguments;
6952 return;
6953 }
6954
6955 // (C++ 13.3.2p2): A candidate function having more than m parameters
6956 // is viable only if the (m+1)st parameter has a default argument
6957 // (8.3.6). For the purposes of overload resolution, the
6958 // parameter list is truncated on the right, so that there are
6959 // exactly m parameters.
6960 unsigned MinRequiredArgs = Method->getMinRequiredArguments();
6961 if (Args.size() < MinRequiredArgs && !PartialOverloading) {
6962 // Not enough arguments.
6963 Candidate.Viable = false;
6964 Candidate.FailureKind = ovl_fail_too_few_arguments;
6965 return;
6966 }
6967
6968 Candidate.Viable = true;
6969
6970 if (Method->isStatic() || ObjectType.isNull())
6971 // The implicit object argument is ignored.
6972 Candidate.IgnoreObjectArgument = true;
6973 else {
6974 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
6975 // Determine the implicit conversion sequence for the object
6976 // parameter.
6977 Candidate.Conversions[ConvIdx] = TryObjectArgumentInitialization(
6978 *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
6979 Method, ActingContext);
6980 if (Candidate.Conversions[ConvIdx].isBad()) {
6981 Candidate.Viable = false;
6982 Candidate.FailureKind = ovl_fail_bad_conversion;
6983 return;
6984 }
6985 }
6986
6987 // (CUDA B.1): Check for invalid calls between targets.
6988 if (getLangOpts().CUDA)
6989 if (const FunctionDecl *Caller = dyn_cast<FunctionDecl>(CurContext))
6990 if (!IsAllowedCUDACall(Caller, Method)) {
6991 Candidate.Viable = false;
6992 Candidate.FailureKind = ovl_fail_bad_target;
6993 return;
6994 }
6995
6996 if (Method->getTrailingRequiresClause()) {
6997 ConstraintSatisfaction Satisfaction;
6998 if (CheckFunctionConstraints(Method, Satisfaction) ||
6999 !Satisfaction.IsSatisfied) {
7000 Candidate.Viable = false;
7001 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
7002 return;
7003 }
7004 }
7005
7006 // Determine the implicit conversion sequences for each of the
7007 // arguments.
7008 for (unsigned ArgIdx = 0; ArgIdx < Args.size(); ++ArgIdx) {
7009 unsigned ConvIdx =
7010 PO == OverloadCandidateParamOrder::Reversed ? 0 : (ArgIdx + 1);
7011 if (Candidate.Conversions[ConvIdx].isInitialized()) {
7012 // We already formed a conversion sequence for this parameter during
7013 // template argument deduction.
7014 } else if (ArgIdx < NumParams) {
7015 // (C++ 13.3.2p3): for F to be a viable function, there shall
7016 // exist for each argument an implicit conversion sequence
7017 // (13.3.3.1) that converts that argument to the corresponding
7018 // parameter of F.
7019 QualType ParamType = Proto->getParamType(ArgIdx);
7020 Candidate.Conversions[ConvIdx]
7021 = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
7022 SuppressUserConversions,
7023 /*InOverloadResolution=*/true,
7024 /*AllowObjCWritebackConversion=*/
7025 getLangOpts().ObjCAutoRefCount);
7026 if (Candidate.Conversions[ConvIdx].isBad()) {
7027 Candidate.Viable = false;
7028 Candidate.FailureKind = ovl_fail_bad_conversion;
7029 return;
7030 }
7031 } else {
7032 // (C++ 13.3.2p2): For the purposes of overload resolution, any
7033 // argument for which there is no corresponding parameter is
7034 // considered to "match the ellipsis" (C+ 13.3.3.1.3).
7035 Candidate.Conversions[ConvIdx].setEllipsis();
7036 }
7037 }
7038
7039 if (EnableIfAttr *FailedAttr =
7040 CheckEnableIf(Method, CandidateSet.getLocation(), Args, true)) {
7041 Candidate.Viable = false;
7042 Candidate.FailureKind = ovl_fail_enable_if;
7043 Candidate.DeductionFailure.Data = FailedAttr;
7044 return;
7045 }
7046
7047 if (Method->isMultiVersion() && Method->hasAttr<TargetAttr>() &&
7048 !Method->getAttr<TargetAttr>()->isDefaultVersion()) {
7049 Candidate.Viable = false;
7050 Candidate.FailureKind = ovl_non_default_multiversion_function;
7051 }
7052 }
7053
7054 /// Add a C++ member function template as a candidate to the candidate
7055 /// set, using template argument deduction to produce an appropriate member
7056 /// function template specialization.
AddMethodTemplateCandidate(FunctionTemplateDecl * MethodTmpl,DeclAccessPair FoundDecl,CXXRecordDecl * ActingContext,TemplateArgumentListInfo * ExplicitTemplateArgs,QualType ObjectType,Expr::Classification ObjectClassification,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool SuppressUserConversions,bool PartialOverloading,OverloadCandidateParamOrder PO)7057 void Sema::AddMethodTemplateCandidate(
7058 FunctionTemplateDecl *MethodTmpl, DeclAccessPair FoundDecl,
7059 CXXRecordDecl *ActingContext,
7060 TemplateArgumentListInfo *ExplicitTemplateArgs, QualType ObjectType,
7061 Expr::Classification ObjectClassification, ArrayRef<Expr *> Args,
7062 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
7063 bool PartialOverloading, OverloadCandidateParamOrder PO) {
7064 if (!CandidateSet.isNewCandidate(MethodTmpl, PO))
7065 return;
7066
7067 // C++ [over.match.funcs]p7:
7068 // In each case where a candidate is a function template, candidate
7069 // function template specializations are generated using template argument
7070 // deduction (14.8.3, 14.8.2). Those candidates are then handled as
7071 // candidate functions in the usual way.113) A given name can refer to one
7072 // or more function templates and also to a set of overloaded non-template
7073 // functions. In such a case, the candidate functions generated from each
7074 // function template are combined with the set of non-template candidate
7075 // functions.
7076 TemplateDeductionInfo Info(CandidateSet.getLocation());
7077 FunctionDecl *Specialization = nullptr;
7078 ConversionSequenceList Conversions;
7079 if (TemplateDeductionResult Result = DeduceTemplateArguments(
7080 MethodTmpl, ExplicitTemplateArgs, Args, Specialization, Info,
7081 PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
7082 return CheckNonDependentConversions(
7083 MethodTmpl, ParamTypes, Args, CandidateSet, Conversions,
7084 SuppressUserConversions, ActingContext, ObjectType,
7085 ObjectClassification, PO);
7086 })) {
7087 OverloadCandidate &Candidate =
7088 CandidateSet.addCandidate(Conversions.size(), Conversions);
7089 Candidate.FoundDecl = FoundDecl;
7090 Candidate.Function = MethodTmpl->getTemplatedDecl();
7091 Candidate.Viable = false;
7092 Candidate.RewriteKind =
7093 CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
7094 Candidate.IsSurrogate = false;
7095 Candidate.IgnoreObjectArgument =
7096 cast<CXXMethodDecl>(Candidate.Function)->isStatic() ||
7097 ObjectType.isNull();
7098 Candidate.ExplicitCallArguments = Args.size();
7099 if (Result == TDK_NonDependentConversionFailure)
7100 Candidate.FailureKind = ovl_fail_bad_conversion;
7101 else {
7102 Candidate.FailureKind = ovl_fail_bad_deduction;
7103 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
7104 Info);
7105 }
7106 return;
7107 }
7108
7109 // Add the function template specialization produced by template argument
7110 // deduction as a candidate.
7111 assert(Specialization && "Missing member function template specialization?");
7112 assert(isa<CXXMethodDecl>(Specialization) &&
7113 "Specialization is not a member function?");
7114 AddMethodCandidate(cast<CXXMethodDecl>(Specialization), FoundDecl,
7115 ActingContext, ObjectType, ObjectClassification, Args,
7116 CandidateSet, SuppressUserConversions, PartialOverloading,
7117 Conversions, PO);
7118 }
7119
7120 /// Determine whether a given function template has a simple explicit specifier
7121 /// or a non-value-dependent explicit-specification that evaluates to true.
isNonDependentlyExplicit(FunctionTemplateDecl * FTD)7122 static bool isNonDependentlyExplicit(FunctionTemplateDecl *FTD) {
7123 return ExplicitSpecifier::getFromDecl(FTD->getTemplatedDecl()).isExplicit();
7124 }
7125
7126 /// Add a C++ function template specialization as a candidate
7127 /// in the candidate set, using template argument deduction to produce
7128 /// an appropriate function template specialization.
AddTemplateOverloadCandidate(FunctionTemplateDecl * FunctionTemplate,DeclAccessPair FoundDecl,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool SuppressUserConversions,bool PartialOverloading,bool AllowExplicit,ADLCallKind IsADLCandidate,OverloadCandidateParamOrder PO)7129 void Sema::AddTemplateOverloadCandidate(
7130 FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
7131 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
7132 OverloadCandidateSet &CandidateSet, bool SuppressUserConversions,
7133 bool PartialOverloading, bool AllowExplicit, ADLCallKind IsADLCandidate,
7134 OverloadCandidateParamOrder PO) {
7135 if (!CandidateSet.isNewCandidate(FunctionTemplate, PO))
7136 return;
7137
7138 // If the function template has a non-dependent explicit specification,
7139 // exclude it now if appropriate; we are not permitted to perform deduction
7140 // and substitution in this case.
7141 if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
7142 OverloadCandidate &Candidate = CandidateSet.addCandidate();
7143 Candidate.FoundDecl = FoundDecl;
7144 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7145 Candidate.Viable = false;
7146 Candidate.FailureKind = ovl_fail_explicit;
7147 return;
7148 }
7149
7150 // C++ [over.match.funcs]p7:
7151 // In each case where a candidate is a function template, candidate
7152 // function template specializations are generated using template argument
7153 // deduction (14.8.3, 14.8.2). Those candidates are then handled as
7154 // candidate functions in the usual way.113) A given name can refer to one
7155 // or more function templates and also to a set of overloaded non-template
7156 // functions. In such a case, the candidate functions generated from each
7157 // function template are combined with the set of non-template candidate
7158 // functions.
7159 TemplateDeductionInfo Info(CandidateSet.getLocation());
7160 FunctionDecl *Specialization = nullptr;
7161 ConversionSequenceList Conversions;
7162 if (TemplateDeductionResult Result = DeduceTemplateArguments(
7163 FunctionTemplate, ExplicitTemplateArgs, Args, Specialization, Info,
7164 PartialOverloading, [&](ArrayRef<QualType> ParamTypes) {
7165 return CheckNonDependentConversions(
7166 FunctionTemplate, ParamTypes, Args, CandidateSet, Conversions,
7167 SuppressUserConversions, nullptr, QualType(), {}, PO);
7168 })) {
7169 OverloadCandidate &Candidate =
7170 CandidateSet.addCandidate(Conversions.size(), Conversions);
7171 Candidate.FoundDecl = FoundDecl;
7172 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7173 Candidate.Viable = false;
7174 Candidate.RewriteKind =
7175 CandidateSet.getRewriteInfo().getRewriteKind(Candidate.Function, PO);
7176 Candidate.IsSurrogate = false;
7177 Candidate.IsADLCandidate = IsADLCandidate;
7178 // Ignore the object argument if there is one, since we don't have an object
7179 // type.
7180 Candidate.IgnoreObjectArgument =
7181 isa<CXXMethodDecl>(Candidate.Function) &&
7182 !isa<CXXConstructorDecl>(Candidate.Function);
7183 Candidate.ExplicitCallArguments = Args.size();
7184 if (Result == TDK_NonDependentConversionFailure)
7185 Candidate.FailureKind = ovl_fail_bad_conversion;
7186 else {
7187 Candidate.FailureKind = ovl_fail_bad_deduction;
7188 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
7189 Info);
7190 }
7191 return;
7192 }
7193
7194 // Add the function template specialization produced by template argument
7195 // deduction as a candidate.
7196 assert(Specialization && "Missing function template specialization?");
7197 AddOverloadCandidate(
7198 Specialization, FoundDecl, Args, CandidateSet, SuppressUserConversions,
7199 PartialOverloading, AllowExplicit,
7200 /*AllowExplicitConversions*/ false, IsADLCandidate, Conversions, PO);
7201 }
7202
7203 /// Check that implicit conversion sequences can be formed for each argument
7204 /// whose corresponding parameter has a non-dependent type, per DR1391's
7205 /// [temp.deduct.call]p10.
CheckNonDependentConversions(FunctionTemplateDecl * FunctionTemplate,ArrayRef<QualType> ParamTypes,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,ConversionSequenceList & Conversions,bool SuppressUserConversions,CXXRecordDecl * ActingContext,QualType ObjectType,Expr::Classification ObjectClassification,OverloadCandidateParamOrder PO)7206 bool Sema::CheckNonDependentConversions(
7207 FunctionTemplateDecl *FunctionTemplate, ArrayRef<QualType> ParamTypes,
7208 ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet,
7209 ConversionSequenceList &Conversions, bool SuppressUserConversions,
7210 CXXRecordDecl *ActingContext, QualType ObjectType,
7211 Expr::Classification ObjectClassification, OverloadCandidateParamOrder PO) {
7212 // FIXME: The cases in which we allow explicit conversions for constructor
7213 // arguments never consider calling a constructor template. It's not clear
7214 // that is correct.
7215 const bool AllowExplicit = false;
7216
7217 auto *FD = FunctionTemplate->getTemplatedDecl();
7218 auto *Method = dyn_cast<CXXMethodDecl>(FD);
7219 bool HasThisConversion = Method && !isa<CXXConstructorDecl>(Method);
7220 unsigned ThisConversions = HasThisConversion ? 1 : 0;
7221
7222 Conversions =
7223 CandidateSet.allocateConversionSequences(ThisConversions + Args.size());
7224
7225 // Overload resolution is always an unevaluated context.
7226 EnterExpressionEvaluationContext Unevaluated(
7227 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7228
7229 // For a method call, check the 'this' conversion here too. DR1391 doesn't
7230 // require that, but this check should never result in a hard error, and
7231 // overload resolution is permitted to sidestep instantiations.
7232 if (HasThisConversion && !cast<CXXMethodDecl>(FD)->isStatic() &&
7233 !ObjectType.isNull()) {
7234 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed ? 1 : 0;
7235 Conversions[ConvIdx] = TryObjectArgumentInitialization(
7236 *this, CandidateSet.getLocation(), ObjectType, ObjectClassification,
7237 Method, ActingContext);
7238 if (Conversions[ConvIdx].isBad())
7239 return true;
7240 }
7241
7242 for (unsigned I = 0, N = std::min(ParamTypes.size(), Args.size()); I != N;
7243 ++I) {
7244 QualType ParamType = ParamTypes[I];
7245 if (!ParamType->isDependentType()) {
7246 unsigned ConvIdx = PO == OverloadCandidateParamOrder::Reversed
7247 ? 0
7248 : (ThisConversions + I);
7249 Conversions[ConvIdx]
7250 = TryCopyInitialization(*this, Args[I], ParamType,
7251 SuppressUserConversions,
7252 /*InOverloadResolution=*/true,
7253 /*AllowObjCWritebackConversion=*/
7254 getLangOpts().ObjCAutoRefCount,
7255 AllowExplicit);
7256 if (Conversions[ConvIdx].isBad())
7257 return true;
7258 }
7259 }
7260
7261 return false;
7262 }
7263
7264 /// Determine whether this is an allowable conversion from the result
7265 /// of an explicit conversion operator to the expected type, per C++
7266 /// [over.match.conv]p1 and [over.match.ref]p1.
7267 ///
7268 /// \param ConvType The return type of the conversion function.
7269 ///
7270 /// \param ToType The type we are converting to.
7271 ///
7272 /// \param AllowObjCPointerConversion Allow a conversion from one
7273 /// Objective-C pointer to another.
7274 ///
7275 /// \returns true if the conversion is allowable, false otherwise.
isAllowableExplicitConversion(Sema & S,QualType ConvType,QualType ToType,bool AllowObjCPointerConversion)7276 static bool isAllowableExplicitConversion(Sema &S,
7277 QualType ConvType, QualType ToType,
7278 bool AllowObjCPointerConversion) {
7279 QualType ToNonRefType = ToType.getNonReferenceType();
7280
7281 // Easy case: the types are the same.
7282 if (S.Context.hasSameUnqualifiedType(ConvType, ToNonRefType))
7283 return true;
7284
7285 // Allow qualification conversions.
7286 bool ObjCLifetimeConversion;
7287 if (S.IsQualificationConversion(ConvType, ToNonRefType, /*CStyle*/false,
7288 ObjCLifetimeConversion))
7289 return true;
7290
7291 // If we're not allowed to consider Objective-C pointer conversions,
7292 // we're done.
7293 if (!AllowObjCPointerConversion)
7294 return false;
7295
7296 // Is this an Objective-C pointer conversion?
7297 bool IncompatibleObjC = false;
7298 QualType ConvertedType;
7299 return S.isObjCPointerConversion(ConvType, ToNonRefType, ConvertedType,
7300 IncompatibleObjC);
7301 }
7302
7303 /// AddConversionCandidate - Add a C++ conversion function as a
7304 /// candidate in the candidate set (C++ [over.match.conv],
7305 /// C++ [over.match.copy]). From is the expression we're converting from,
7306 /// and ToType is the type that we're eventually trying to convert to
7307 /// (which may or may not be the same type as the type that the
7308 /// conversion function produces).
AddConversionCandidate(CXXConversionDecl * Conversion,DeclAccessPair FoundDecl,CXXRecordDecl * ActingContext,Expr * From,QualType ToType,OverloadCandidateSet & CandidateSet,bool AllowObjCConversionOnExplicit,bool AllowExplicit,bool AllowResultConversion)7309 void Sema::AddConversionCandidate(
7310 CXXConversionDecl *Conversion, DeclAccessPair FoundDecl,
7311 CXXRecordDecl *ActingContext, Expr *From, QualType ToType,
7312 OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
7313 bool AllowExplicit, bool AllowResultConversion) {
7314 assert(!Conversion->getDescribedFunctionTemplate() &&
7315 "Conversion function templates use AddTemplateConversionCandidate");
7316 QualType ConvType = Conversion->getConversionType().getNonReferenceType();
7317 if (!CandidateSet.isNewCandidate(Conversion))
7318 return;
7319
7320 // If the conversion function has an undeduced return type, trigger its
7321 // deduction now.
7322 if (getLangOpts().CPlusPlus14 && ConvType->isUndeducedType()) {
7323 if (DeduceReturnType(Conversion, From->getExprLoc()))
7324 return;
7325 ConvType = Conversion->getConversionType().getNonReferenceType();
7326 }
7327
7328 // If we don't allow any conversion of the result type, ignore conversion
7329 // functions that don't convert to exactly (possibly cv-qualified) T.
7330 if (!AllowResultConversion &&
7331 !Context.hasSameUnqualifiedType(Conversion->getConversionType(), ToType))
7332 return;
7333
7334 // Per C++ [over.match.conv]p1, [over.match.ref]p1, an explicit conversion
7335 // operator is only a candidate if its return type is the target type or
7336 // can be converted to the target type with a qualification conversion.
7337 //
7338 // FIXME: Include such functions in the candidate list and explain why we
7339 // can't select them.
7340 if (Conversion->isExplicit() &&
7341 !isAllowableExplicitConversion(*this, ConvType, ToType,
7342 AllowObjCConversionOnExplicit))
7343 return;
7344
7345 // Overload resolution is always an unevaluated context.
7346 EnterExpressionEvaluationContext Unevaluated(
7347 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7348
7349 // Add this candidate
7350 OverloadCandidate &Candidate = CandidateSet.addCandidate(1);
7351 Candidate.FoundDecl = FoundDecl;
7352 Candidate.Function = Conversion;
7353 Candidate.IsSurrogate = false;
7354 Candidate.IgnoreObjectArgument = false;
7355 Candidate.FinalConversion.setAsIdentityConversion();
7356 Candidate.FinalConversion.setFromType(ConvType);
7357 Candidate.FinalConversion.setAllToTypes(ToType);
7358 Candidate.Viable = true;
7359 Candidate.ExplicitCallArguments = 1;
7360
7361 // Explicit functions are not actually candidates at all if we're not
7362 // allowing them in this context, but keep them around so we can point
7363 // to them in diagnostics.
7364 if (!AllowExplicit && Conversion->isExplicit()) {
7365 Candidate.Viable = false;
7366 Candidate.FailureKind = ovl_fail_explicit;
7367 return;
7368 }
7369
7370 // C++ [over.match.funcs]p4:
7371 // For conversion functions, the function is considered to be a member of
7372 // the class of the implicit implied object argument for the purpose of
7373 // defining the type of the implicit object parameter.
7374 //
7375 // Determine the implicit conversion sequence for the implicit
7376 // object parameter.
7377 QualType ImplicitParamType = From->getType();
7378 if (const PointerType *FromPtrType = ImplicitParamType->getAs<PointerType>())
7379 ImplicitParamType = FromPtrType->getPointeeType();
7380 CXXRecordDecl *ConversionContext
7381 = cast<CXXRecordDecl>(ImplicitParamType->castAs<RecordType>()->getDecl());
7382
7383 Candidate.Conversions[0] = TryObjectArgumentInitialization(
7384 *this, CandidateSet.getLocation(), From->getType(),
7385 From->Classify(Context), Conversion, ConversionContext);
7386
7387 if (Candidate.Conversions[0].isBad()) {
7388 Candidate.Viable = false;
7389 Candidate.FailureKind = ovl_fail_bad_conversion;
7390 return;
7391 }
7392
7393 if (Conversion->getTrailingRequiresClause()) {
7394 ConstraintSatisfaction Satisfaction;
7395 if (CheckFunctionConstraints(Conversion, Satisfaction) ||
7396 !Satisfaction.IsSatisfied) {
7397 Candidate.Viable = false;
7398 Candidate.FailureKind = ovl_fail_constraints_not_satisfied;
7399 return;
7400 }
7401 }
7402
7403 // We won't go through a user-defined type conversion function to convert a
7404 // derived to base as such conversions are given Conversion Rank. They only
7405 // go through a copy constructor. 13.3.3.1.2-p4 [over.ics.user]
7406 QualType FromCanon
7407 = Context.getCanonicalType(From->getType().getUnqualifiedType());
7408 QualType ToCanon = Context.getCanonicalType(ToType).getUnqualifiedType();
7409 if (FromCanon == ToCanon ||
7410 IsDerivedFrom(CandidateSet.getLocation(), FromCanon, ToCanon)) {
7411 Candidate.Viable = false;
7412 Candidate.FailureKind = ovl_fail_trivial_conversion;
7413 return;
7414 }
7415
7416 // To determine what the conversion from the result of calling the
7417 // conversion function to the type we're eventually trying to
7418 // convert to (ToType), we need to synthesize a call to the
7419 // conversion function and attempt copy initialization from it. This
7420 // makes sure that we get the right semantics with respect to
7421 // lvalues/rvalues and the type. Fortunately, we can allocate this
7422 // call on the stack and we don't need its arguments to be
7423 // well-formed.
7424 DeclRefExpr ConversionRef(Context, Conversion, false, Conversion->getType(),
7425 VK_LValue, From->getBeginLoc());
7426 ImplicitCastExpr ConversionFn(ImplicitCastExpr::OnStack,
7427 Context.getPointerType(Conversion->getType()),
7428 CK_FunctionToPointerDecay, &ConversionRef,
7429 VK_PRValue, FPOptionsOverride());
7430
7431 QualType ConversionType = Conversion->getConversionType();
7432 if (!isCompleteType(From->getBeginLoc(), ConversionType)) {
7433 Candidate.Viable = false;
7434 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7435 return;
7436 }
7437
7438 ExprValueKind VK = Expr::getValueKindForType(ConversionType);
7439
7440 // Note that it is safe to allocate CallExpr on the stack here because
7441 // there are 0 arguments (i.e., nothing is allocated using ASTContext's
7442 // allocator).
7443 QualType CallResultType = ConversionType.getNonLValueExprType(Context);
7444
7445 alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
7446 CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
7447 Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());
7448
7449 ImplicitConversionSequence ICS =
7450 TryCopyInitialization(*this, TheTemporaryCall, ToType,
7451 /*SuppressUserConversions=*/true,
7452 /*InOverloadResolution=*/false,
7453 /*AllowObjCWritebackConversion=*/false);
7454
7455 switch (ICS.getKind()) {
7456 case ImplicitConversionSequence::StandardConversion:
7457 Candidate.FinalConversion = ICS.Standard;
7458
7459 // C++ [over.ics.user]p3:
7460 // If the user-defined conversion is specified by a specialization of a
7461 // conversion function template, the second standard conversion sequence
7462 // shall have exact match rank.
7463 if (Conversion->getPrimaryTemplate() &&
7464 GetConversionRank(ICS.Standard.Second) != ICR_Exact_Match) {
7465 Candidate.Viable = false;
7466 Candidate.FailureKind = ovl_fail_final_conversion_not_exact;
7467 return;
7468 }
7469
7470 // C++0x [dcl.init.ref]p5:
7471 // In the second case, if the reference is an rvalue reference and
7472 // the second standard conversion sequence of the user-defined
7473 // conversion sequence includes an lvalue-to-rvalue conversion, the
7474 // program is ill-formed.
7475 if (ToType->isRValueReferenceType() &&
7476 ICS.Standard.First == ICK_Lvalue_To_Rvalue) {
7477 Candidate.Viable = false;
7478 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7479 return;
7480 }
7481 break;
7482
7483 case ImplicitConversionSequence::BadConversion:
7484 Candidate.Viable = false;
7485 Candidate.FailureKind = ovl_fail_bad_final_conversion;
7486 return;
7487
7488 default:
7489 llvm_unreachable(
7490 "Can only end up with a standard conversion sequence or failure");
7491 }
7492
7493 if (EnableIfAttr *FailedAttr =
7494 CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
7495 Candidate.Viable = false;
7496 Candidate.FailureKind = ovl_fail_enable_if;
7497 Candidate.DeductionFailure.Data = FailedAttr;
7498 return;
7499 }
7500
7501 if (Conversion->isMultiVersion() && Conversion->hasAttr<TargetAttr>() &&
7502 !Conversion->getAttr<TargetAttr>()->isDefaultVersion()) {
7503 Candidate.Viable = false;
7504 Candidate.FailureKind = ovl_non_default_multiversion_function;
7505 }
7506 }
7507
7508 /// Adds a conversion function template specialization
7509 /// candidate to the overload set, using template argument deduction
7510 /// to deduce the template arguments of the conversion function
7511 /// template from the type that we are converting to (C++
7512 /// [temp.deduct.conv]).
AddTemplateConversionCandidate(FunctionTemplateDecl * FunctionTemplate,DeclAccessPair FoundDecl,CXXRecordDecl * ActingDC,Expr * From,QualType ToType,OverloadCandidateSet & CandidateSet,bool AllowObjCConversionOnExplicit,bool AllowExplicit,bool AllowResultConversion)7513 void Sema::AddTemplateConversionCandidate(
7514 FunctionTemplateDecl *FunctionTemplate, DeclAccessPair FoundDecl,
7515 CXXRecordDecl *ActingDC, Expr *From, QualType ToType,
7516 OverloadCandidateSet &CandidateSet, bool AllowObjCConversionOnExplicit,
7517 bool AllowExplicit, bool AllowResultConversion) {
7518 assert(isa<CXXConversionDecl>(FunctionTemplate->getTemplatedDecl()) &&
7519 "Only conversion function templates permitted here");
7520
7521 if (!CandidateSet.isNewCandidate(FunctionTemplate))
7522 return;
7523
7524 // If the function template has a non-dependent explicit specification,
7525 // exclude it now if appropriate; we are not permitted to perform deduction
7526 // and substitution in this case.
7527 if (!AllowExplicit && isNonDependentlyExplicit(FunctionTemplate)) {
7528 OverloadCandidate &Candidate = CandidateSet.addCandidate();
7529 Candidate.FoundDecl = FoundDecl;
7530 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7531 Candidate.Viable = false;
7532 Candidate.FailureKind = ovl_fail_explicit;
7533 return;
7534 }
7535
7536 TemplateDeductionInfo Info(CandidateSet.getLocation());
7537 CXXConversionDecl *Specialization = nullptr;
7538 if (TemplateDeductionResult Result
7539 = DeduceTemplateArguments(FunctionTemplate, ToType,
7540 Specialization, Info)) {
7541 OverloadCandidate &Candidate = CandidateSet.addCandidate();
7542 Candidate.FoundDecl = FoundDecl;
7543 Candidate.Function = FunctionTemplate->getTemplatedDecl();
7544 Candidate.Viable = false;
7545 Candidate.FailureKind = ovl_fail_bad_deduction;
7546 Candidate.IsSurrogate = false;
7547 Candidate.IgnoreObjectArgument = false;
7548 Candidate.ExplicitCallArguments = 1;
7549 Candidate.DeductionFailure = MakeDeductionFailureInfo(Context, Result,
7550 Info);
7551 return;
7552 }
7553
7554 // Add the conversion function template specialization produced by
7555 // template argument deduction as a candidate.
7556 assert(Specialization && "Missing function template specialization?");
7557 AddConversionCandidate(Specialization, FoundDecl, ActingDC, From, ToType,
7558 CandidateSet, AllowObjCConversionOnExplicit,
7559 AllowExplicit, AllowResultConversion);
7560 }
7561
7562 /// AddSurrogateCandidate - Adds a "surrogate" candidate function that
7563 /// converts the given @c Object to a function pointer via the
7564 /// conversion function @c Conversion, and then attempts to call it
7565 /// with the given arguments (C++ [over.call.object]p2-4). Proto is
7566 /// the type of function that we'll eventually be calling.
AddSurrogateCandidate(CXXConversionDecl * Conversion,DeclAccessPair FoundDecl,CXXRecordDecl * ActingContext,const FunctionProtoType * Proto,Expr * Object,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)7567 void Sema::AddSurrogateCandidate(CXXConversionDecl *Conversion,
7568 DeclAccessPair FoundDecl,
7569 CXXRecordDecl *ActingContext,
7570 const FunctionProtoType *Proto,
7571 Expr *Object,
7572 ArrayRef<Expr *> Args,
7573 OverloadCandidateSet& CandidateSet) {
7574 if (!CandidateSet.isNewCandidate(Conversion))
7575 return;
7576
7577 // Overload resolution is always an unevaluated context.
7578 EnterExpressionEvaluationContext Unevaluated(
7579 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7580
7581 OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size() + 1);
7582 Candidate.FoundDecl = FoundDecl;
7583 Candidate.Function = nullptr;
7584 Candidate.Surrogate = Conversion;
7585 Candidate.Viable = true;
7586 Candidate.IsSurrogate = true;
7587 Candidate.IgnoreObjectArgument = false;
7588 Candidate.ExplicitCallArguments = Args.size();
7589
7590 // Determine the implicit conversion sequence for the implicit
7591 // object parameter.
7592 ImplicitConversionSequence ObjectInit = TryObjectArgumentInitialization(
7593 *this, CandidateSet.getLocation(), Object->getType(),
7594 Object->Classify(Context), Conversion, ActingContext);
7595 if (ObjectInit.isBad()) {
7596 Candidate.Viable = false;
7597 Candidate.FailureKind = ovl_fail_bad_conversion;
7598 Candidate.Conversions[0] = ObjectInit;
7599 return;
7600 }
7601
7602 // The first conversion is actually a user-defined conversion whose
7603 // first conversion is ObjectInit's standard conversion (which is
7604 // effectively a reference binding). Record it as such.
7605 Candidate.Conversions[0].setUserDefined();
7606 Candidate.Conversions[0].UserDefined.Before = ObjectInit.Standard;
7607 Candidate.Conversions[0].UserDefined.EllipsisConversion = false;
7608 Candidate.Conversions[0].UserDefined.HadMultipleCandidates = false;
7609 Candidate.Conversions[0].UserDefined.ConversionFunction = Conversion;
7610 Candidate.Conversions[0].UserDefined.FoundConversionFunction = FoundDecl;
7611 Candidate.Conversions[0].UserDefined.After
7612 = Candidate.Conversions[0].UserDefined.Before;
7613 Candidate.Conversions[0].UserDefined.After.setAsIdentityConversion();
7614
7615 // Find the
7616 unsigned NumParams = Proto->getNumParams();
7617
7618 // (C++ 13.3.2p2): A candidate function having fewer than m
7619 // parameters is viable only if it has an ellipsis in its parameter
7620 // list (8.3.5).
7621 if (Args.size() > NumParams && !Proto->isVariadic()) {
7622 Candidate.Viable = false;
7623 Candidate.FailureKind = ovl_fail_too_many_arguments;
7624 return;
7625 }
7626
7627 // Function types don't have any default arguments, so just check if
7628 // we have enough arguments.
7629 if (Args.size() < NumParams) {
7630 // Not enough arguments.
7631 Candidate.Viable = false;
7632 Candidate.FailureKind = ovl_fail_too_few_arguments;
7633 return;
7634 }
7635
7636 // Determine the implicit conversion sequences for each of the
7637 // arguments.
7638 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
7639 if (ArgIdx < NumParams) {
7640 // (C++ 13.3.2p3): for F to be a viable function, there shall
7641 // exist for each argument an implicit conversion sequence
7642 // (13.3.3.1) that converts that argument to the corresponding
7643 // parameter of F.
7644 QualType ParamType = Proto->getParamType(ArgIdx);
7645 Candidate.Conversions[ArgIdx + 1]
7646 = TryCopyInitialization(*this, Args[ArgIdx], ParamType,
7647 /*SuppressUserConversions=*/false,
7648 /*InOverloadResolution=*/false,
7649 /*AllowObjCWritebackConversion=*/
7650 getLangOpts().ObjCAutoRefCount);
7651 if (Candidate.Conversions[ArgIdx + 1].isBad()) {
7652 Candidate.Viable = false;
7653 Candidate.FailureKind = ovl_fail_bad_conversion;
7654 return;
7655 }
7656 } else {
7657 // (C++ 13.3.2p2): For the purposes of overload resolution, any
7658 // argument for which there is no corresponding parameter is
7659 // considered to ""match the ellipsis" (C+ 13.3.3.1.3).
7660 Candidate.Conversions[ArgIdx + 1].setEllipsis();
7661 }
7662 }
7663
7664 if (EnableIfAttr *FailedAttr =
7665 CheckEnableIf(Conversion, CandidateSet.getLocation(), None)) {
7666 Candidate.Viable = false;
7667 Candidate.FailureKind = ovl_fail_enable_if;
7668 Candidate.DeductionFailure.Data = FailedAttr;
7669 return;
7670 }
7671 }
7672
7673 /// Add all of the non-member operator function declarations in the given
7674 /// function set to the overload candidate set.
AddNonMemberOperatorCandidates(const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,TemplateArgumentListInfo * ExplicitTemplateArgs)7675 void Sema::AddNonMemberOperatorCandidates(
7676 const UnresolvedSetImpl &Fns, ArrayRef<Expr *> Args,
7677 OverloadCandidateSet &CandidateSet,
7678 TemplateArgumentListInfo *ExplicitTemplateArgs) {
7679 for (UnresolvedSetIterator F = Fns.begin(), E = Fns.end(); F != E; ++F) {
7680 NamedDecl *D = F.getDecl()->getUnderlyingDecl();
7681 ArrayRef<Expr *> FunctionArgs = Args;
7682
7683 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D);
7684 FunctionDecl *FD =
7685 FunTmpl ? FunTmpl->getTemplatedDecl() : cast<FunctionDecl>(D);
7686
7687 // Don't consider rewritten functions if we're not rewriting.
7688 if (!CandidateSet.getRewriteInfo().isAcceptableCandidate(FD))
7689 continue;
7690
7691 assert(!isa<CXXMethodDecl>(FD) &&
7692 "unqualified operator lookup found a member function");
7693
7694 if (FunTmpl) {
7695 AddTemplateOverloadCandidate(FunTmpl, F.getPair(), ExplicitTemplateArgs,
7696 FunctionArgs, CandidateSet);
7697 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
7698 AddTemplateOverloadCandidate(
7699 FunTmpl, F.getPair(), ExplicitTemplateArgs,
7700 {FunctionArgs[1], FunctionArgs[0]}, CandidateSet, false, false,
7701 true, ADLCallKind::NotADL, OverloadCandidateParamOrder::Reversed);
7702 } else {
7703 if (ExplicitTemplateArgs)
7704 continue;
7705 AddOverloadCandidate(FD, F.getPair(), FunctionArgs, CandidateSet);
7706 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD))
7707 AddOverloadCandidate(FD, F.getPair(),
7708 {FunctionArgs[1], FunctionArgs[0]}, CandidateSet,
7709 false, false, true, false, ADLCallKind::NotADL,
7710 None, OverloadCandidateParamOrder::Reversed);
7711 }
7712 }
7713 }
7714
7715 /// Add overload candidates for overloaded operators that are
7716 /// member functions.
7717 ///
7718 /// Add the overloaded operator candidates that are member functions
7719 /// for the operator Op that was used in an operator expression such
7720 /// as "x Op y". , Args/NumArgs provides the operator arguments, and
7721 /// CandidateSet will store the added overload candidates. (C++
7722 /// [over.match.oper]).
AddMemberOperatorCandidates(OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,OverloadCandidateParamOrder PO)7723 void Sema::AddMemberOperatorCandidates(OverloadedOperatorKind Op,
7724 SourceLocation OpLoc,
7725 ArrayRef<Expr *> Args,
7726 OverloadCandidateSet &CandidateSet,
7727 OverloadCandidateParamOrder PO) {
7728 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
7729
7730 // C++ [over.match.oper]p3:
7731 // For a unary operator @ with an operand of a type whose
7732 // cv-unqualified version is T1, and for a binary operator @ with
7733 // a left operand of a type whose cv-unqualified version is T1 and
7734 // a right operand of a type whose cv-unqualified version is T2,
7735 // three sets of candidate functions, designated member
7736 // candidates, non-member candidates and built-in candidates, are
7737 // constructed as follows:
7738 QualType T1 = Args[0]->getType();
7739
7740 // -- If T1 is a complete class type or a class currently being
7741 // defined, the set of member candidates is the result of the
7742 // qualified lookup of T1::operator@ (13.3.1.1.1); otherwise,
7743 // the set of member candidates is empty.
7744 if (const RecordType *T1Rec = T1->getAs<RecordType>()) {
7745 // Complete the type if it can be completed.
7746 if (!isCompleteType(OpLoc, T1) && !T1Rec->isBeingDefined())
7747 return;
7748 // If the type is neither complete nor being defined, bail out now.
7749 if (!T1Rec->getDecl()->getDefinition())
7750 return;
7751
7752 LookupResult Operators(*this, OpName, OpLoc, LookupOrdinaryName);
7753 LookupQualifiedName(Operators, T1Rec->getDecl());
7754 Operators.suppressDiagnostics();
7755
7756 for (LookupResult::iterator Oper = Operators.begin(),
7757 OperEnd = Operators.end();
7758 Oper != OperEnd;
7759 ++Oper)
7760 AddMethodCandidate(Oper.getPair(), Args[0]->getType(),
7761 Args[0]->Classify(Context), Args.slice(1),
7762 CandidateSet, /*SuppressUserConversion=*/false, PO);
7763 }
7764 }
7765
7766 /// AddBuiltinCandidate - Add a candidate for a built-in
7767 /// operator. ResultTy and ParamTys are the result and parameter types
7768 /// of the built-in candidate, respectively. Args and NumArgs are the
7769 /// arguments being passed to the candidate. IsAssignmentOperator
7770 /// should be true when this built-in candidate is an assignment
7771 /// operator. NumContextualBoolArguments is the number of arguments
7772 /// (at the beginning of the argument list) that will be contextually
7773 /// converted to bool.
AddBuiltinCandidate(QualType * ParamTys,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool IsAssignmentOperator,unsigned NumContextualBoolArguments)7774 void Sema::AddBuiltinCandidate(QualType *ParamTys, ArrayRef<Expr *> Args,
7775 OverloadCandidateSet& CandidateSet,
7776 bool IsAssignmentOperator,
7777 unsigned NumContextualBoolArguments) {
7778 // Overload resolution is always an unevaluated context.
7779 EnterExpressionEvaluationContext Unevaluated(
7780 *this, Sema::ExpressionEvaluationContext::Unevaluated);
7781
7782 // Add this candidate
7783 OverloadCandidate &Candidate = CandidateSet.addCandidate(Args.size());
7784 Candidate.FoundDecl = DeclAccessPair::make(nullptr, AS_none);
7785 Candidate.Function = nullptr;
7786 Candidate.IsSurrogate = false;
7787 Candidate.IgnoreObjectArgument = false;
7788 std::copy(ParamTys, ParamTys + Args.size(), Candidate.BuiltinParamTypes);
7789
7790 // Determine the implicit conversion sequences for each of the
7791 // arguments.
7792 Candidate.Viable = true;
7793 Candidate.ExplicitCallArguments = Args.size();
7794 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
7795 // C++ [over.match.oper]p4:
7796 // For the built-in assignment operators, conversions of the
7797 // left operand are restricted as follows:
7798 // -- no temporaries are introduced to hold the left operand, and
7799 // -- no user-defined conversions are applied to the left
7800 // operand to achieve a type match with the left-most
7801 // parameter of a built-in candidate.
7802 //
7803 // We block these conversions by turning off user-defined
7804 // conversions, since that is the only way that initialization of
7805 // a reference to a non-class type can occur from something that
7806 // is not of the same type.
7807 if (ArgIdx < NumContextualBoolArguments) {
7808 assert(ParamTys[ArgIdx] == Context.BoolTy &&
7809 "Contextual conversion to bool requires bool type");
7810 Candidate.Conversions[ArgIdx]
7811 = TryContextuallyConvertToBool(*this, Args[ArgIdx]);
7812 } else {
7813 Candidate.Conversions[ArgIdx]
7814 = TryCopyInitialization(*this, Args[ArgIdx], ParamTys[ArgIdx],
7815 ArgIdx == 0 && IsAssignmentOperator,
7816 /*InOverloadResolution=*/false,
7817 /*AllowObjCWritebackConversion=*/
7818 getLangOpts().ObjCAutoRefCount);
7819 }
7820 if (Candidate.Conversions[ArgIdx].isBad()) {
7821 Candidate.Viable = false;
7822 Candidate.FailureKind = ovl_fail_bad_conversion;
7823 break;
7824 }
7825 }
7826 }
7827
7828 namespace {
7829
7830 /// BuiltinCandidateTypeSet - A set of types that will be used for the
7831 /// candidate operator functions for built-in operators (C++
7832 /// [over.built]). The types are separated into pointer types and
7833 /// enumeration types.
7834 class BuiltinCandidateTypeSet {
7835 /// TypeSet - A set of types.
7836 typedef llvm::SetVector<QualType, SmallVector<QualType, 8>,
7837 llvm::SmallPtrSet<QualType, 8>> TypeSet;
7838
7839 /// PointerTypes - The set of pointer types that will be used in the
7840 /// built-in candidates.
7841 TypeSet PointerTypes;
7842
7843 /// MemberPointerTypes - The set of member pointer types that will be
7844 /// used in the built-in candidates.
7845 TypeSet MemberPointerTypes;
7846
7847 /// EnumerationTypes - The set of enumeration types that will be
7848 /// used in the built-in candidates.
7849 TypeSet EnumerationTypes;
7850
7851 /// The set of vector types that will be used in the built-in
7852 /// candidates.
7853 TypeSet VectorTypes;
7854
7855 /// The set of matrix types that will be used in the built-in
7856 /// candidates.
7857 TypeSet MatrixTypes;
7858
7859 /// A flag indicating non-record types are viable candidates
7860 bool HasNonRecordTypes;
7861
7862 /// A flag indicating whether either arithmetic or enumeration types
7863 /// were present in the candidate set.
7864 bool HasArithmeticOrEnumeralTypes;
7865
7866 /// A flag indicating whether the nullptr type was present in the
7867 /// candidate set.
7868 bool HasNullPtrType;
7869
7870 /// Sema - The semantic analysis instance where we are building the
7871 /// candidate type set.
7872 Sema &SemaRef;
7873
7874 /// Context - The AST context in which we will build the type sets.
7875 ASTContext &Context;
7876
7877 bool AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
7878 const Qualifiers &VisibleQuals);
7879 bool AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty);
7880
7881 public:
7882 /// iterator - Iterates through the types that are part of the set.
7883 typedef TypeSet::iterator iterator;
7884
BuiltinCandidateTypeSet(Sema & SemaRef)7885 BuiltinCandidateTypeSet(Sema &SemaRef)
7886 : HasNonRecordTypes(false),
7887 HasArithmeticOrEnumeralTypes(false),
7888 HasNullPtrType(false),
7889 SemaRef(SemaRef),
7890 Context(SemaRef.Context) { }
7891
7892 void AddTypesConvertedFrom(QualType Ty,
7893 SourceLocation Loc,
7894 bool AllowUserConversions,
7895 bool AllowExplicitConversions,
7896 const Qualifiers &VisibleTypeConversionsQuals);
7897
pointer_types()7898 llvm::iterator_range<iterator> pointer_types() { return PointerTypes; }
member_pointer_types()7899 llvm::iterator_range<iterator> member_pointer_types() {
7900 return MemberPointerTypes;
7901 }
enumeration_types()7902 llvm::iterator_range<iterator> enumeration_types() {
7903 return EnumerationTypes;
7904 }
vector_types()7905 llvm::iterator_range<iterator> vector_types() { return VectorTypes; }
matrix_types()7906 llvm::iterator_range<iterator> matrix_types() { return MatrixTypes; }
7907
containsMatrixType(QualType Ty) const7908 bool containsMatrixType(QualType Ty) const { return MatrixTypes.count(Ty); }
hasNonRecordTypes()7909 bool hasNonRecordTypes() { return HasNonRecordTypes; }
hasArithmeticOrEnumeralTypes()7910 bool hasArithmeticOrEnumeralTypes() { return HasArithmeticOrEnumeralTypes; }
hasNullPtrType() const7911 bool hasNullPtrType() const { return HasNullPtrType; }
7912 };
7913
7914 } // end anonymous namespace
7915
7916 /// AddPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty to
7917 /// the set of pointer types along with any more-qualified variants of
7918 /// that type. For example, if @p Ty is "int const *", this routine
7919 /// will add "int const *", "int const volatile *", "int const
7920 /// restrict *", and "int const volatile restrict *" to the set of
7921 /// pointer types. Returns true if the add of @p Ty itself succeeded,
7922 /// false otherwise.
7923 ///
7924 /// FIXME: what to do about extended qualifiers?
7925 bool
AddPointerWithMoreQualifiedTypeVariants(QualType Ty,const Qualifiers & VisibleQuals)7926 BuiltinCandidateTypeSet::AddPointerWithMoreQualifiedTypeVariants(QualType Ty,
7927 const Qualifiers &VisibleQuals) {
7928
7929 // Insert this type.
7930 if (!PointerTypes.insert(Ty))
7931 return false;
7932
7933 QualType PointeeTy;
7934 const PointerType *PointerTy = Ty->getAs<PointerType>();
7935 bool buildObjCPtr = false;
7936 if (!PointerTy) {
7937 const ObjCObjectPointerType *PTy = Ty->castAs<ObjCObjectPointerType>();
7938 PointeeTy = PTy->getPointeeType();
7939 buildObjCPtr = true;
7940 } else {
7941 PointeeTy = PointerTy->getPointeeType();
7942 }
7943
7944 // Don't add qualified variants of arrays. For one, they're not allowed
7945 // (the qualifier would sink to the element type), and for another, the
7946 // only overload situation where it matters is subscript or pointer +- int,
7947 // and those shouldn't have qualifier variants anyway.
7948 if (PointeeTy->isArrayType())
7949 return true;
7950
7951 unsigned BaseCVR = PointeeTy.getCVRQualifiers();
7952 bool hasVolatile = VisibleQuals.hasVolatile();
7953 bool hasRestrict = VisibleQuals.hasRestrict();
7954
7955 // Iterate through all strict supersets of BaseCVR.
7956 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
7957 if ((CVR | BaseCVR) != CVR) continue;
7958 // Skip over volatile if no volatile found anywhere in the types.
7959 if ((CVR & Qualifiers::Volatile) && !hasVolatile) continue;
7960
7961 // Skip over restrict if no restrict found anywhere in the types, or if
7962 // the type cannot be restrict-qualified.
7963 if ((CVR & Qualifiers::Restrict) &&
7964 (!hasRestrict ||
7965 (!(PointeeTy->isAnyPointerType() || PointeeTy->isReferenceType()))))
7966 continue;
7967
7968 // Build qualified pointee type.
7969 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
7970
7971 // Build qualified pointer type.
7972 QualType QPointerTy;
7973 if (!buildObjCPtr)
7974 QPointerTy = Context.getPointerType(QPointeeTy);
7975 else
7976 QPointerTy = Context.getObjCObjectPointerType(QPointeeTy);
7977
7978 // Insert qualified pointer type.
7979 PointerTypes.insert(QPointerTy);
7980 }
7981
7982 return true;
7983 }
7984
7985 /// AddMemberPointerWithMoreQualifiedTypeVariants - Add the pointer type @p Ty
7986 /// to the set of pointer types along with any more-qualified variants of
7987 /// that type. For example, if @p Ty is "int const *", this routine
7988 /// will add "int const *", "int const volatile *", "int const
7989 /// restrict *", and "int const volatile restrict *" to the set of
7990 /// pointer types. Returns true if the add of @p Ty itself succeeded,
7991 /// false otherwise.
7992 ///
7993 /// FIXME: what to do about extended qualifiers?
7994 bool
AddMemberPointerWithMoreQualifiedTypeVariants(QualType Ty)7995 BuiltinCandidateTypeSet::AddMemberPointerWithMoreQualifiedTypeVariants(
7996 QualType Ty) {
7997 // Insert this type.
7998 if (!MemberPointerTypes.insert(Ty))
7999 return false;
8000
8001 const MemberPointerType *PointerTy = Ty->getAs<MemberPointerType>();
8002 assert(PointerTy && "type was not a member pointer type!");
8003
8004 QualType PointeeTy = PointerTy->getPointeeType();
8005 // Don't add qualified variants of arrays. For one, they're not allowed
8006 // (the qualifier would sink to the element type), and for another, the
8007 // only overload situation where it matters is subscript or pointer +- int,
8008 // and those shouldn't have qualifier variants anyway.
8009 if (PointeeTy->isArrayType())
8010 return true;
8011 const Type *ClassTy = PointerTy->getClass();
8012
8013 // Iterate through all strict supersets of the pointee type's CVR
8014 // qualifiers.
8015 unsigned BaseCVR = PointeeTy.getCVRQualifiers();
8016 for (unsigned CVR = BaseCVR+1; CVR <= Qualifiers::CVRMask; ++CVR) {
8017 if ((CVR | BaseCVR) != CVR) continue;
8018
8019 QualType QPointeeTy = Context.getCVRQualifiedType(PointeeTy, CVR);
8020 MemberPointerTypes.insert(
8021 Context.getMemberPointerType(QPointeeTy, ClassTy));
8022 }
8023
8024 return true;
8025 }
8026
8027 /// AddTypesConvertedFrom - Add each of the types to which the type @p
8028 /// Ty can be implicit converted to the given set of @p Types. We're
8029 /// primarily interested in pointer types and enumeration types. We also
8030 /// take member pointer types, for the conditional operator.
8031 /// AllowUserConversions is true if we should look at the conversion
8032 /// functions of a class type, and AllowExplicitConversions if we
8033 /// should also include the explicit conversion functions of a class
8034 /// type.
8035 void
AddTypesConvertedFrom(QualType Ty,SourceLocation Loc,bool AllowUserConversions,bool AllowExplicitConversions,const Qualifiers & VisibleQuals)8036 BuiltinCandidateTypeSet::AddTypesConvertedFrom(QualType Ty,
8037 SourceLocation Loc,
8038 bool AllowUserConversions,
8039 bool AllowExplicitConversions,
8040 const Qualifiers &VisibleQuals) {
8041 // Only deal with canonical types.
8042 Ty = Context.getCanonicalType(Ty);
8043
8044 // Look through reference types; they aren't part of the type of an
8045 // expression for the purposes of conversions.
8046 if (const ReferenceType *RefTy = Ty->getAs<ReferenceType>())
8047 Ty = RefTy->getPointeeType();
8048
8049 // If we're dealing with an array type, decay to the pointer.
8050 if (Ty->isArrayType())
8051 Ty = SemaRef.Context.getArrayDecayedType(Ty);
8052
8053 // Otherwise, we don't care about qualifiers on the type.
8054 Ty = Ty.getLocalUnqualifiedType();
8055
8056 // Flag if we ever add a non-record type.
8057 const RecordType *TyRec = Ty->getAs<RecordType>();
8058 HasNonRecordTypes = HasNonRecordTypes || !TyRec;
8059
8060 // Flag if we encounter an arithmetic type.
8061 HasArithmeticOrEnumeralTypes =
8062 HasArithmeticOrEnumeralTypes || Ty->isArithmeticType();
8063
8064 if (Ty->isObjCIdType() || Ty->isObjCClassType())
8065 PointerTypes.insert(Ty);
8066 else if (Ty->getAs<PointerType>() || Ty->getAs<ObjCObjectPointerType>()) {
8067 // Insert our type, and its more-qualified variants, into the set
8068 // of types.
8069 if (!AddPointerWithMoreQualifiedTypeVariants(Ty, VisibleQuals))
8070 return;
8071 } else if (Ty->isMemberPointerType()) {
8072 // Member pointers are far easier, since the pointee can't be converted.
8073 if (!AddMemberPointerWithMoreQualifiedTypeVariants(Ty))
8074 return;
8075 } else if (Ty->isEnumeralType()) {
8076 HasArithmeticOrEnumeralTypes = true;
8077 EnumerationTypes.insert(Ty);
8078 } else if (Ty->isVectorType()) {
8079 // We treat vector types as arithmetic types in many contexts as an
8080 // extension.
8081 HasArithmeticOrEnumeralTypes = true;
8082 VectorTypes.insert(Ty);
8083 } else if (Ty->isMatrixType()) {
8084 // Similar to vector types, we treat vector types as arithmetic types in
8085 // many contexts as an extension.
8086 HasArithmeticOrEnumeralTypes = true;
8087 MatrixTypes.insert(Ty);
8088 } else if (Ty->isNullPtrType()) {
8089 HasNullPtrType = true;
8090 } else if (AllowUserConversions && TyRec) {
8091 // No conversion functions in incomplete types.
8092 if (!SemaRef.isCompleteType(Loc, Ty))
8093 return;
8094
8095 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
8096 for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
8097 if (isa<UsingShadowDecl>(D))
8098 D = cast<UsingShadowDecl>(D)->getTargetDecl();
8099
8100 // Skip conversion function templates; they don't tell us anything
8101 // about which builtin types we can convert to.
8102 if (isa<FunctionTemplateDecl>(D))
8103 continue;
8104
8105 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
8106 if (AllowExplicitConversions || !Conv->isExplicit()) {
8107 AddTypesConvertedFrom(Conv->getConversionType(), Loc, false, false,
8108 VisibleQuals);
8109 }
8110 }
8111 }
8112 }
8113 /// Helper function for adjusting address spaces for the pointer or reference
8114 /// operands of builtin operators depending on the argument.
AdjustAddressSpaceForBuiltinOperandType(Sema & S,QualType T,Expr * Arg)8115 static QualType AdjustAddressSpaceForBuiltinOperandType(Sema &S, QualType T,
8116 Expr *Arg) {
8117 return S.Context.getAddrSpaceQualType(T, Arg->getType().getAddressSpace());
8118 }
8119
8120 /// Helper function for AddBuiltinOperatorCandidates() that adds
8121 /// the volatile- and non-volatile-qualified assignment operators for the
8122 /// given type to the candidate set.
AddBuiltinAssignmentOperatorCandidates(Sema & S,QualType T,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)8123 static void AddBuiltinAssignmentOperatorCandidates(Sema &S,
8124 QualType T,
8125 ArrayRef<Expr *> Args,
8126 OverloadCandidateSet &CandidateSet) {
8127 QualType ParamTypes[2];
8128
8129 // T& operator=(T&, T)
8130 ParamTypes[0] = S.Context.getLValueReferenceType(
8131 AdjustAddressSpaceForBuiltinOperandType(S, T, Args[0]));
8132 ParamTypes[1] = T;
8133 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8134 /*IsAssignmentOperator=*/true);
8135
8136 if (!S.Context.getCanonicalType(T).isVolatileQualified()) {
8137 // volatile T& operator=(volatile T&, T)
8138 ParamTypes[0] = S.Context.getLValueReferenceType(
8139 AdjustAddressSpaceForBuiltinOperandType(S, S.Context.getVolatileType(T),
8140 Args[0]));
8141 ParamTypes[1] = T;
8142 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8143 /*IsAssignmentOperator=*/true);
8144 }
8145 }
8146
8147 /// CollectVRQualifiers - This routine returns Volatile/Restrict qualifiers,
8148 /// if any, found in visible type conversion functions found in ArgExpr's type.
CollectVRQualifiers(ASTContext & Context,Expr * ArgExpr)8149 static Qualifiers CollectVRQualifiers(ASTContext &Context, Expr* ArgExpr) {
8150 Qualifiers VRQuals;
8151 const RecordType *TyRec;
8152 if (const MemberPointerType *RHSMPType =
8153 ArgExpr->getType()->getAs<MemberPointerType>())
8154 TyRec = RHSMPType->getClass()->getAs<RecordType>();
8155 else
8156 TyRec = ArgExpr->getType()->getAs<RecordType>();
8157 if (!TyRec) {
8158 // Just to be safe, assume the worst case.
8159 VRQuals.addVolatile();
8160 VRQuals.addRestrict();
8161 return VRQuals;
8162 }
8163
8164 CXXRecordDecl *ClassDecl = cast<CXXRecordDecl>(TyRec->getDecl());
8165 if (!ClassDecl->hasDefinition())
8166 return VRQuals;
8167
8168 for (NamedDecl *D : ClassDecl->getVisibleConversionFunctions()) {
8169 if (isa<UsingShadowDecl>(D))
8170 D = cast<UsingShadowDecl>(D)->getTargetDecl();
8171 if (CXXConversionDecl *Conv = dyn_cast<CXXConversionDecl>(D)) {
8172 QualType CanTy = Context.getCanonicalType(Conv->getConversionType());
8173 if (const ReferenceType *ResTypeRef = CanTy->getAs<ReferenceType>())
8174 CanTy = ResTypeRef->getPointeeType();
8175 // Need to go down the pointer/mempointer chain and add qualifiers
8176 // as see them.
8177 bool done = false;
8178 while (!done) {
8179 if (CanTy.isRestrictQualified())
8180 VRQuals.addRestrict();
8181 if (const PointerType *ResTypePtr = CanTy->getAs<PointerType>())
8182 CanTy = ResTypePtr->getPointeeType();
8183 else if (const MemberPointerType *ResTypeMPtr =
8184 CanTy->getAs<MemberPointerType>())
8185 CanTy = ResTypeMPtr->getPointeeType();
8186 else
8187 done = true;
8188 if (CanTy.isVolatileQualified())
8189 VRQuals.addVolatile();
8190 if (VRQuals.hasRestrict() && VRQuals.hasVolatile())
8191 return VRQuals;
8192 }
8193 }
8194 }
8195 return VRQuals;
8196 }
8197
8198 namespace {
8199
8200 /// Helper class to manage the addition of builtin operator overload
8201 /// candidates. It provides shared state and utility methods used throughout
8202 /// the process, as well as a helper method to add each group of builtin
8203 /// operator overloads from the standard to a candidate set.
8204 class BuiltinOperatorOverloadBuilder {
8205 // Common instance state available to all overload candidate addition methods.
8206 Sema &S;
8207 ArrayRef<Expr *> Args;
8208 Qualifiers VisibleTypeConversionsQuals;
8209 bool HasArithmeticOrEnumeralCandidateType;
8210 SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes;
8211 OverloadCandidateSet &CandidateSet;
8212
8213 static constexpr int ArithmeticTypesCap = 24;
8214 SmallVector<CanQualType, ArithmeticTypesCap> ArithmeticTypes;
8215
8216 // Define some indices used to iterate over the arithmetic types in
8217 // ArithmeticTypes. The "promoted arithmetic types" are the arithmetic
8218 // types are that preserved by promotion (C++ [over.built]p2).
8219 unsigned FirstIntegralType,
8220 LastIntegralType;
8221 unsigned FirstPromotedIntegralType,
8222 LastPromotedIntegralType;
8223 unsigned FirstPromotedArithmeticType,
8224 LastPromotedArithmeticType;
8225 unsigned NumArithmeticTypes;
8226
InitArithmeticTypes()8227 void InitArithmeticTypes() {
8228 // Start of promoted types.
8229 FirstPromotedArithmeticType = 0;
8230 ArithmeticTypes.push_back(S.Context.FloatTy);
8231 ArithmeticTypes.push_back(S.Context.DoubleTy);
8232 ArithmeticTypes.push_back(S.Context.LongDoubleTy);
8233 if (S.Context.getTargetInfo().hasFloat128Type())
8234 ArithmeticTypes.push_back(S.Context.Float128Ty);
8235 if (S.Context.getTargetInfo().hasIbm128Type())
8236 ArithmeticTypes.push_back(S.Context.Ibm128Ty);
8237
8238 // Start of integral types.
8239 FirstIntegralType = ArithmeticTypes.size();
8240 FirstPromotedIntegralType = ArithmeticTypes.size();
8241 ArithmeticTypes.push_back(S.Context.IntTy);
8242 ArithmeticTypes.push_back(S.Context.LongTy);
8243 ArithmeticTypes.push_back(S.Context.LongLongTy);
8244 if (S.Context.getTargetInfo().hasInt128Type() ||
8245 (S.Context.getAuxTargetInfo() &&
8246 S.Context.getAuxTargetInfo()->hasInt128Type()))
8247 ArithmeticTypes.push_back(S.Context.Int128Ty);
8248 ArithmeticTypes.push_back(S.Context.UnsignedIntTy);
8249 ArithmeticTypes.push_back(S.Context.UnsignedLongTy);
8250 ArithmeticTypes.push_back(S.Context.UnsignedLongLongTy);
8251 if (S.Context.getTargetInfo().hasInt128Type() ||
8252 (S.Context.getAuxTargetInfo() &&
8253 S.Context.getAuxTargetInfo()->hasInt128Type()))
8254 ArithmeticTypes.push_back(S.Context.UnsignedInt128Ty);
8255 LastPromotedIntegralType = ArithmeticTypes.size();
8256 LastPromotedArithmeticType = ArithmeticTypes.size();
8257 // End of promoted types.
8258
8259 ArithmeticTypes.push_back(S.Context.BoolTy);
8260 ArithmeticTypes.push_back(S.Context.CharTy);
8261 ArithmeticTypes.push_back(S.Context.WCharTy);
8262 if (S.Context.getLangOpts().Char8)
8263 ArithmeticTypes.push_back(S.Context.Char8Ty);
8264 ArithmeticTypes.push_back(S.Context.Char16Ty);
8265 ArithmeticTypes.push_back(S.Context.Char32Ty);
8266 ArithmeticTypes.push_back(S.Context.SignedCharTy);
8267 ArithmeticTypes.push_back(S.Context.ShortTy);
8268 ArithmeticTypes.push_back(S.Context.UnsignedCharTy);
8269 ArithmeticTypes.push_back(S.Context.UnsignedShortTy);
8270 LastIntegralType = ArithmeticTypes.size();
8271 NumArithmeticTypes = ArithmeticTypes.size();
8272 // End of integral types.
8273 // FIXME: What about complex? What about half?
8274
8275 assert(ArithmeticTypes.size() <= ArithmeticTypesCap &&
8276 "Enough inline storage for all arithmetic types.");
8277 }
8278
8279 /// Helper method to factor out the common pattern of adding overloads
8280 /// for '++' and '--' builtin operators.
addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,bool HasVolatile,bool HasRestrict)8281 void addPlusPlusMinusMinusStyleOverloads(QualType CandidateTy,
8282 bool HasVolatile,
8283 bool HasRestrict) {
8284 QualType ParamTypes[2] = {
8285 S.Context.getLValueReferenceType(CandidateTy),
8286 S.Context.IntTy
8287 };
8288
8289 // Non-volatile version.
8290 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8291
8292 // Use a heuristic to reduce number of builtin candidates in the set:
8293 // add volatile version only if there are conversions to a volatile type.
8294 if (HasVolatile) {
8295 ParamTypes[0] =
8296 S.Context.getLValueReferenceType(
8297 S.Context.getVolatileType(CandidateTy));
8298 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8299 }
8300
8301 // Add restrict version only if there are conversions to a restrict type
8302 // and our candidate type is a non-restrict-qualified pointer.
8303 if (HasRestrict && CandidateTy->isAnyPointerType() &&
8304 !CandidateTy.isRestrictQualified()) {
8305 ParamTypes[0]
8306 = S.Context.getLValueReferenceType(
8307 S.Context.getCVRQualifiedType(CandidateTy, Qualifiers::Restrict));
8308 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8309
8310 if (HasVolatile) {
8311 ParamTypes[0]
8312 = S.Context.getLValueReferenceType(
8313 S.Context.getCVRQualifiedType(CandidateTy,
8314 (Qualifiers::Volatile |
8315 Qualifiers::Restrict)));
8316 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8317 }
8318 }
8319
8320 }
8321
8322 /// Helper to add an overload candidate for a binary builtin with types \p L
8323 /// and \p R.
AddCandidate(QualType L,QualType R)8324 void AddCandidate(QualType L, QualType R) {
8325 QualType LandR[2] = {L, R};
8326 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8327 }
8328
8329 public:
BuiltinOperatorOverloadBuilder(Sema & S,ArrayRef<Expr * > Args,Qualifiers VisibleTypeConversionsQuals,bool HasArithmeticOrEnumeralCandidateType,SmallVectorImpl<BuiltinCandidateTypeSet> & CandidateTypes,OverloadCandidateSet & CandidateSet)8330 BuiltinOperatorOverloadBuilder(
8331 Sema &S, ArrayRef<Expr *> Args,
8332 Qualifiers VisibleTypeConversionsQuals,
8333 bool HasArithmeticOrEnumeralCandidateType,
8334 SmallVectorImpl<BuiltinCandidateTypeSet> &CandidateTypes,
8335 OverloadCandidateSet &CandidateSet)
8336 : S(S), Args(Args),
8337 VisibleTypeConversionsQuals(VisibleTypeConversionsQuals),
8338 HasArithmeticOrEnumeralCandidateType(
8339 HasArithmeticOrEnumeralCandidateType),
8340 CandidateTypes(CandidateTypes),
8341 CandidateSet(CandidateSet) {
8342
8343 InitArithmeticTypes();
8344 }
8345
8346 // Increment is deprecated for bool since C++17.
8347 //
8348 // C++ [over.built]p3:
8349 //
8350 // For every pair (T, VQ), where T is an arithmetic type other
8351 // than bool, and VQ is either volatile or empty, there exist
8352 // candidate operator functions of the form
8353 //
8354 // VQ T& operator++(VQ T&);
8355 // T operator++(VQ T&, int);
8356 //
8357 // C++ [over.built]p4:
8358 //
8359 // For every pair (T, VQ), where T is an arithmetic type other
8360 // than bool, and VQ is either volatile or empty, there exist
8361 // candidate operator functions of the form
8362 //
8363 // VQ T& operator--(VQ T&);
8364 // T operator--(VQ T&, int);
addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op)8365 void addPlusPlusMinusMinusArithmeticOverloads(OverloadedOperatorKind Op) {
8366 if (!HasArithmeticOrEnumeralCandidateType)
8367 return;
8368
8369 for (unsigned Arith = 0; Arith < NumArithmeticTypes; ++Arith) {
8370 const auto TypeOfT = ArithmeticTypes[Arith];
8371 if (TypeOfT == S.Context.BoolTy) {
8372 if (Op == OO_MinusMinus)
8373 continue;
8374 if (Op == OO_PlusPlus && S.getLangOpts().CPlusPlus17)
8375 continue;
8376 }
8377 addPlusPlusMinusMinusStyleOverloads(
8378 TypeOfT,
8379 VisibleTypeConversionsQuals.hasVolatile(),
8380 VisibleTypeConversionsQuals.hasRestrict());
8381 }
8382 }
8383
8384 // C++ [over.built]p5:
8385 //
8386 // For every pair (T, VQ), where T is a cv-qualified or
8387 // cv-unqualified object type, and VQ is either volatile or
8388 // empty, there exist candidate operator functions of the form
8389 //
8390 // T*VQ& operator++(T*VQ&);
8391 // T*VQ& operator--(T*VQ&);
8392 // T* operator++(T*VQ&, int);
8393 // T* operator--(T*VQ&, int);
addPlusPlusMinusMinusPointerOverloads()8394 void addPlusPlusMinusMinusPointerOverloads() {
8395 for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
8396 // Skip pointer types that aren't pointers to object types.
8397 if (!PtrTy->getPointeeType()->isObjectType())
8398 continue;
8399
8400 addPlusPlusMinusMinusStyleOverloads(
8401 PtrTy,
8402 (!PtrTy.isVolatileQualified() &&
8403 VisibleTypeConversionsQuals.hasVolatile()),
8404 (!PtrTy.isRestrictQualified() &&
8405 VisibleTypeConversionsQuals.hasRestrict()));
8406 }
8407 }
8408
8409 // C++ [over.built]p6:
8410 // For every cv-qualified or cv-unqualified object type T, there
8411 // exist candidate operator functions of the form
8412 //
8413 // T& operator*(T*);
8414 //
8415 // C++ [over.built]p7:
8416 // For every function type T that does not have cv-qualifiers or a
8417 // ref-qualifier, there exist candidate operator functions of the form
8418 // T& operator*(T*);
addUnaryStarPointerOverloads()8419 void addUnaryStarPointerOverloads() {
8420 for (QualType ParamTy : CandidateTypes[0].pointer_types()) {
8421 QualType PointeeTy = ParamTy->getPointeeType();
8422 if (!PointeeTy->isObjectType() && !PointeeTy->isFunctionType())
8423 continue;
8424
8425 if (const FunctionProtoType *Proto =PointeeTy->getAs<FunctionProtoType>())
8426 if (Proto->getMethodQuals() || Proto->getRefQualifier())
8427 continue;
8428
8429 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
8430 }
8431 }
8432
8433 // C++ [over.built]p9:
8434 // For every promoted arithmetic type T, there exist candidate
8435 // operator functions of the form
8436 //
8437 // T operator+(T);
8438 // T operator-(T);
addUnaryPlusOrMinusArithmeticOverloads()8439 void addUnaryPlusOrMinusArithmeticOverloads() {
8440 if (!HasArithmeticOrEnumeralCandidateType)
8441 return;
8442
8443 for (unsigned Arith = FirstPromotedArithmeticType;
8444 Arith < LastPromotedArithmeticType; ++Arith) {
8445 QualType ArithTy = ArithmeticTypes[Arith];
8446 S.AddBuiltinCandidate(&ArithTy, Args, CandidateSet);
8447 }
8448
8449 // Extension: We also add these operators for vector types.
8450 for (QualType VecTy : CandidateTypes[0].vector_types())
8451 S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
8452 }
8453
8454 // C++ [over.built]p8:
8455 // For every type T, there exist candidate operator functions of
8456 // the form
8457 //
8458 // T* operator+(T*);
addUnaryPlusPointerOverloads()8459 void addUnaryPlusPointerOverloads() {
8460 for (QualType ParamTy : CandidateTypes[0].pointer_types())
8461 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet);
8462 }
8463
8464 // C++ [over.built]p10:
8465 // For every promoted integral type T, there exist candidate
8466 // operator functions of the form
8467 //
8468 // T operator~(T);
addUnaryTildePromotedIntegralOverloads()8469 void addUnaryTildePromotedIntegralOverloads() {
8470 if (!HasArithmeticOrEnumeralCandidateType)
8471 return;
8472
8473 for (unsigned Int = FirstPromotedIntegralType;
8474 Int < LastPromotedIntegralType; ++Int) {
8475 QualType IntTy = ArithmeticTypes[Int];
8476 S.AddBuiltinCandidate(&IntTy, Args, CandidateSet);
8477 }
8478
8479 // Extension: We also add this operator for vector types.
8480 for (QualType VecTy : CandidateTypes[0].vector_types())
8481 S.AddBuiltinCandidate(&VecTy, Args, CandidateSet);
8482 }
8483
8484 // C++ [over.match.oper]p16:
8485 // For every pointer to member type T or type std::nullptr_t, there
8486 // exist candidate operator functions of the form
8487 //
8488 // bool operator==(T,T);
8489 // bool operator!=(T,T);
addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads()8490 void addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads() {
8491 /// Set of (canonical) types that we've already handled.
8492 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8493
8494 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8495 for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
8496 // Don't add the same builtin candidate twice.
8497 if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
8498 continue;
8499
8500 QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
8501 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8502 }
8503
8504 if (CandidateTypes[ArgIdx].hasNullPtrType()) {
8505 CanQualType NullPtrTy = S.Context.getCanonicalType(S.Context.NullPtrTy);
8506 if (AddedTypes.insert(NullPtrTy).second) {
8507 QualType ParamTypes[2] = { NullPtrTy, NullPtrTy };
8508 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8509 }
8510 }
8511 }
8512 }
8513
8514 // C++ [over.built]p15:
8515 //
8516 // For every T, where T is an enumeration type or a pointer type,
8517 // there exist candidate operator functions of the form
8518 //
8519 // bool operator<(T, T);
8520 // bool operator>(T, T);
8521 // bool operator<=(T, T);
8522 // bool operator>=(T, T);
8523 // bool operator==(T, T);
8524 // bool operator!=(T, T);
8525 // R operator<=>(T, T)
addGenericBinaryPointerOrEnumeralOverloads(bool IsSpaceship)8526 void addGenericBinaryPointerOrEnumeralOverloads(bool IsSpaceship) {
8527 // C++ [over.match.oper]p3:
8528 // [...]the built-in candidates include all of the candidate operator
8529 // functions defined in 13.6 that, compared to the given operator, [...]
8530 // do not have the same parameter-type-list as any non-template non-member
8531 // candidate.
8532 //
8533 // Note that in practice, this only affects enumeration types because there
8534 // aren't any built-in candidates of record type, and a user-defined operator
8535 // must have an operand of record or enumeration type. Also, the only other
8536 // overloaded operator with enumeration arguments, operator=,
8537 // cannot be overloaded for enumeration types, so this is the only place
8538 // where we must suppress candidates like this.
8539 llvm::DenseSet<std::pair<CanQualType, CanQualType> >
8540 UserDefinedBinaryOperators;
8541
8542 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8543 if (!CandidateTypes[ArgIdx].enumeration_types().empty()) {
8544 for (OverloadCandidateSet::iterator C = CandidateSet.begin(),
8545 CEnd = CandidateSet.end();
8546 C != CEnd; ++C) {
8547 if (!C->Viable || !C->Function || C->Function->getNumParams() != 2)
8548 continue;
8549
8550 if (C->Function->isFunctionTemplateSpecialization())
8551 continue;
8552
8553 // We interpret "same parameter-type-list" as applying to the
8554 // "synthesized candidate, with the order of the two parameters
8555 // reversed", not to the original function.
8556 bool Reversed = C->isReversed();
8557 QualType FirstParamType = C->Function->getParamDecl(Reversed ? 1 : 0)
8558 ->getType()
8559 .getUnqualifiedType();
8560 QualType SecondParamType = C->Function->getParamDecl(Reversed ? 0 : 1)
8561 ->getType()
8562 .getUnqualifiedType();
8563
8564 // Skip if either parameter isn't of enumeral type.
8565 if (!FirstParamType->isEnumeralType() ||
8566 !SecondParamType->isEnumeralType())
8567 continue;
8568
8569 // Add this operator to the set of known user-defined operators.
8570 UserDefinedBinaryOperators.insert(
8571 std::make_pair(S.Context.getCanonicalType(FirstParamType),
8572 S.Context.getCanonicalType(SecondParamType)));
8573 }
8574 }
8575 }
8576
8577 /// Set of (canonical) types that we've already handled.
8578 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8579
8580 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
8581 for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
8582 // Don't add the same builtin candidate twice.
8583 if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
8584 continue;
8585 if (IsSpaceship && PtrTy->isFunctionPointerType())
8586 continue;
8587
8588 QualType ParamTypes[2] = {PtrTy, PtrTy};
8589 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8590 }
8591 for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
8592 CanQualType CanonType = S.Context.getCanonicalType(EnumTy);
8593
8594 // Don't add the same builtin candidate twice, or if a user defined
8595 // candidate exists.
8596 if (!AddedTypes.insert(CanonType).second ||
8597 UserDefinedBinaryOperators.count(std::make_pair(CanonType,
8598 CanonType)))
8599 continue;
8600 QualType ParamTypes[2] = {EnumTy, EnumTy};
8601 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8602 }
8603 }
8604 }
8605
8606 // C++ [over.built]p13:
8607 //
8608 // For every cv-qualified or cv-unqualified object type T
8609 // there exist candidate operator functions of the form
8610 //
8611 // T* operator+(T*, ptrdiff_t);
8612 // T& operator[](T*, ptrdiff_t); [BELOW]
8613 // T* operator-(T*, ptrdiff_t);
8614 // T* operator+(ptrdiff_t, T*);
8615 // T& operator[](ptrdiff_t, T*); [BELOW]
8616 //
8617 // C++ [over.built]p14:
8618 //
8619 // For every T, where T is a pointer to object type, there
8620 // exist candidate operator functions of the form
8621 //
8622 // ptrdiff_t operator-(T, T);
addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op)8623 void addBinaryPlusOrMinusPointerOverloads(OverloadedOperatorKind Op) {
8624 /// Set of (canonical) types that we've already handled.
8625 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8626
8627 for (int Arg = 0; Arg < 2; ++Arg) {
8628 QualType AsymmetricParamTypes[2] = {
8629 S.Context.getPointerDiffType(),
8630 S.Context.getPointerDiffType(),
8631 };
8632 for (QualType PtrTy : CandidateTypes[Arg].pointer_types()) {
8633 QualType PointeeTy = PtrTy->getPointeeType();
8634 if (!PointeeTy->isObjectType())
8635 continue;
8636
8637 AsymmetricParamTypes[Arg] = PtrTy;
8638 if (Arg == 0 || Op == OO_Plus) {
8639 // operator+(T*, ptrdiff_t) or operator-(T*, ptrdiff_t)
8640 // T* operator+(ptrdiff_t, T*);
8641 S.AddBuiltinCandidate(AsymmetricParamTypes, Args, CandidateSet);
8642 }
8643 if (Op == OO_Minus) {
8644 // ptrdiff_t operator-(T, T);
8645 if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
8646 continue;
8647
8648 QualType ParamTypes[2] = {PtrTy, PtrTy};
8649 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
8650 }
8651 }
8652 }
8653 }
8654
8655 // C++ [over.built]p12:
8656 //
8657 // For every pair of promoted arithmetic types L and R, there
8658 // exist candidate operator functions of the form
8659 //
8660 // LR operator*(L, R);
8661 // LR operator/(L, R);
8662 // LR operator+(L, R);
8663 // LR operator-(L, R);
8664 // bool operator<(L, R);
8665 // bool operator>(L, R);
8666 // bool operator<=(L, R);
8667 // bool operator>=(L, R);
8668 // bool operator==(L, R);
8669 // bool operator!=(L, R);
8670 //
8671 // where LR is the result of the usual arithmetic conversions
8672 // between types L and R.
8673 //
8674 // C++ [over.built]p24:
8675 //
8676 // For every pair of promoted arithmetic types L and R, there exist
8677 // candidate operator functions of the form
8678 //
8679 // LR operator?(bool, L, R);
8680 //
8681 // where LR is the result of the usual arithmetic conversions
8682 // between types L and R.
8683 // Our candidates ignore the first parameter.
addGenericBinaryArithmeticOverloads()8684 void addGenericBinaryArithmeticOverloads() {
8685 if (!HasArithmeticOrEnumeralCandidateType)
8686 return;
8687
8688 for (unsigned Left = FirstPromotedArithmeticType;
8689 Left < LastPromotedArithmeticType; ++Left) {
8690 for (unsigned Right = FirstPromotedArithmeticType;
8691 Right < LastPromotedArithmeticType; ++Right) {
8692 QualType LandR[2] = { ArithmeticTypes[Left],
8693 ArithmeticTypes[Right] };
8694 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8695 }
8696 }
8697
8698 // Extension: Add the binary operators ==, !=, <, <=, >=, >, *, /, and the
8699 // conditional operator for vector types.
8700 for (QualType Vec1Ty : CandidateTypes[0].vector_types())
8701 for (QualType Vec2Ty : CandidateTypes[1].vector_types()) {
8702 QualType LandR[2] = {Vec1Ty, Vec2Ty};
8703 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8704 }
8705 }
8706
8707 /// Add binary operator overloads for each candidate matrix type M1, M2:
8708 /// * (M1, M1) -> M1
8709 /// * (M1, M1.getElementType()) -> M1
8710 /// * (M2.getElementType(), M2) -> M2
8711 /// * (M2, M2) -> M2 // Only if M2 is not part of CandidateTypes[0].
addMatrixBinaryArithmeticOverloads()8712 void addMatrixBinaryArithmeticOverloads() {
8713 if (!HasArithmeticOrEnumeralCandidateType)
8714 return;
8715
8716 for (QualType M1 : CandidateTypes[0].matrix_types()) {
8717 AddCandidate(M1, cast<MatrixType>(M1)->getElementType());
8718 AddCandidate(M1, M1);
8719 }
8720
8721 for (QualType M2 : CandidateTypes[1].matrix_types()) {
8722 AddCandidate(cast<MatrixType>(M2)->getElementType(), M2);
8723 if (!CandidateTypes[0].containsMatrixType(M2))
8724 AddCandidate(M2, M2);
8725 }
8726 }
8727
8728 // C++2a [over.built]p14:
8729 //
8730 // For every integral type T there exists a candidate operator function
8731 // of the form
8732 //
8733 // std::strong_ordering operator<=>(T, T)
8734 //
8735 // C++2a [over.built]p15:
8736 //
8737 // For every pair of floating-point types L and R, there exists a candidate
8738 // operator function of the form
8739 //
8740 // std::partial_ordering operator<=>(L, R);
8741 //
8742 // FIXME: The current specification for integral types doesn't play nice with
8743 // the direction of p0946r0, which allows mixed integral and unscoped-enum
8744 // comparisons. Under the current spec this can lead to ambiguity during
8745 // overload resolution. For example:
8746 //
8747 // enum A : int {a};
8748 // auto x = (a <=> (long)42);
8749 //
8750 // error: call is ambiguous for arguments 'A' and 'long'.
8751 // note: candidate operator<=>(int, int)
8752 // note: candidate operator<=>(long, long)
8753 //
8754 // To avoid this error, this function deviates from the specification and adds
8755 // the mixed overloads `operator<=>(L, R)` where L and R are promoted
8756 // arithmetic types (the same as the generic relational overloads).
8757 //
8758 // For now this function acts as a placeholder.
addThreeWayArithmeticOverloads()8759 void addThreeWayArithmeticOverloads() {
8760 addGenericBinaryArithmeticOverloads();
8761 }
8762
8763 // C++ [over.built]p17:
8764 //
8765 // For every pair of promoted integral types L and R, there
8766 // exist candidate operator functions of the form
8767 //
8768 // LR operator%(L, R);
8769 // LR operator&(L, R);
8770 // LR operator^(L, R);
8771 // LR operator|(L, R);
8772 // L operator<<(L, R);
8773 // L operator>>(L, R);
8774 //
8775 // where LR is the result of the usual arithmetic conversions
8776 // between types L and R.
addBinaryBitwiseArithmeticOverloads()8777 void addBinaryBitwiseArithmeticOverloads() {
8778 if (!HasArithmeticOrEnumeralCandidateType)
8779 return;
8780
8781 for (unsigned Left = FirstPromotedIntegralType;
8782 Left < LastPromotedIntegralType; ++Left) {
8783 for (unsigned Right = FirstPromotedIntegralType;
8784 Right < LastPromotedIntegralType; ++Right) {
8785 QualType LandR[2] = { ArithmeticTypes[Left],
8786 ArithmeticTypes[Right] };
8787 S.AddBuiltinCandidate(LandR, Args, CandidateSet);
8788 }
8789 }
8790 }
8791
8792 // C++ [over.built]p20:
8793 //
8794 // For every pair (T, VQ), where T is an enumeration or
8795 // pointer to member type and VQ is either volatile or
8796 // empty, there exist candidate operator functions of the form
8797 //
8798 // VQ T& operator=(VQ T&, T);
addAssignmentMemberPointerOrEnumeralOverloads()8799 void addAssignmentMemberPointerOrEnumeralOverloads() {
8800 /// Set of (canonical) types that we've already handled.
8801 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8802
8803 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
8804 for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
8805 if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
8806 continue;
8807
8808 AddBuiltinAssignmentOperatorCandidates(S, EnumTy, Args, CandidateSet);
8809 }
8810
8811 for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
8812 if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
8813 continue;
8814
8815 AddBuiltinAssignmentOperatorCandidates(S, MemPtrTy, Args, CandidateSet);
8816 }
8817 }
8818 }
8819
8820 // C++ [over.built]p19:
8821 //
8822 // For every pair (T, VQ), where T is any type and VQ is either
8823 // volatile or empty, there exist candidate operator functions
8824 // of the form
8825 //
8826 // T*VQ& operator=(T*VQ&, T*);
8827 //
8828 // C++ [over.built]p21:
8829 //
8830 // For every pair (T, VQ), where T is a cv-qualified or
8831 // cv-unqualified object type and VQ is either volatile or
8832 // empty, there exist candidate operator functions of the form
8833 //
8834 // T*VQ& operator+=(T*VQ&, ptrdiff_t);
8835 // T*VQ& operator-=(T*VQ&, ptrdiff_t);
addAssignmentPointerOverloads(bool isEqualOp)8836 void addAssignmentPointerOverloads(bool isEqualOp) {
8837 /// Set of (canonical) types that we've already handled.
8838 llvm::SmallPtrSet<QualType, 8> AddedTypes;
8839
8840 for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
8841 // If this is operator=, keep track of the builtin candidates we added.
8842 if (isEqualOp)
8843 AddedTypes.insert(S.Context.getCanonicalType(PtrTy));
8844 else if (!PtrTy->getPointeeType()->isObjectType())
8845 continue;
8846
8847 // non-volatile version
8848 QualType ParamTypes[2] = {
8849 S.Context.getLValueReferenceType(PtrTy),
8850 isEqualOp ? PtrTy : S.Context.getPointerDiffType(),
8851 };
8852 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8853 /*IsAssignmentOperator=*/ isEqualOp);
8854
8855 bool NeedVolatile = !PtrTy.isVolatileQualified() &&
8856 VisibleTypeConversionsQuals.hasVolatile();
8857 if (NeedVolatile) {
8858 // volatile version
8859 ParamTypes[0] =
8860 S.Context.getLValueReferenceType(S.Context.getVolatileType(PtrTy));
8861 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8862 /*IsAssignmentOperator=*/isEqualOp);
8863 }
8864
8865 if (!PtrTy.isRestrictQualified() &&
8866 VisibleTypeConversionsQuals.hasRestrict()) {
8867 // restrict version
8868 ParamTypes[0] =
8869 S.Context.getLValueReferenceType(S.Context.getRestrictType(PtrTy));
8870 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8871 /*IsAssignmentOperator=*/isEqualOp);
8872
8873 if (NeedVolatile) {
8874 // volatile restrict version
8875 ParamTypes[0] =
8876 S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
8877 PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
8878 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8879 /*IsAssignmentOperator=*/isEqualOp);
8880 }
8881 }
8882 }
8883
8884 if (isEqualOp) {
8885 for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
8886 // Make sure we don't add the same candidate twice.
8887 if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
8888 continue;
8889
8890 QualType ParamTypes[2] = {
8891 S.Context.getLValueReferenceType(PtrTy),
8892 PtrTy,
8893 };
8894
8895 // non-volatile version
8896 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8897 /*IsAssignmentOperator=*/true);
8898
8899 bool NeedVolatile = !PtrTy.isVolatileQualified() &&
8900 VisibleTypeConversionsQuals.hasVolatile();
8901 if (NeedVolatile) {
8902 // volatile version
8903 ParamTypes[0] = S.Context.getLValueReferenceType(
8904 S.Context.getVolatileType(PtrTy));
8905 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8906 /*IsAssignmentOperator=*/true);
8907 }
8908
8909 if (!PtrTy.isRestrictQualified() &&
8910 VisibleTypeConversionsQuals.hasRestrict()) {
8911 // restrict version
8912 ParamTypes[0] = S.Context.getLValueReferenceType(
8913 S.Context.getRestrictType(PtrTy));
8914 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8915 /*IsAssignmentOperator=*/true);
8916
8917 if (NeedVolatile) {
8918 // volatile restrict version
8919 ParamTypes[0] =
8920 S.Context.getLValueReferenceType(S.Context.getCVRQualifiedType(
8921 PtrTy, (Qualifiers::Volatile | Qualifiers::Restrict)));
8922 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8923 /*IsAssignmentOperator=*/true);
8924 }
8925 }
8926 }
8927 }
8928 }
8929
8930 // C++ [over.built]p18:
8931 //
8932 // For every triple (L, VQ, R), where L is an arithmetic type,
8933 // VQ is either volatile or empty, and R is a promoted
8934 // arithmetic type, there exist candidate operator functions of
8935 // the form
8936 //
8937 // VQ L& operator=(VQ L&, R);
8938 // VQ L& operator*=(VQ L&, R);
8939 // VQ L& operator/=(VQ L&, R);
8940 // VQ L& operator+=(VQ L&, R);
8941 // VQ L& operator-=(VQ L&, R);
addAssignmentArithmeticOverloads(bool isEqualOp)8942 void addAssignmentArithmeticOverloads(bool isEqualOp) {
8943 if (!HasArithmeticOrEnumeralCandidateType)
8944 return;
8945
8946 for (unsigned Left = 0; Left < NumArithmeticTypes; ++Left) {
8947 for (unsigned Right = FirstPromotedArithmeticType;
8948 Right < LastPromotedArithmeticType; ++Right) {
8949 QualType ParamTypes[2];
8950 ParamTypes[1] = ArithmeticTypes[Right];
8951 auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
8952 S, ArithmeticTypes[Left], Args[0]);
8953 // Add this built-in operator as a candidate (VQ is empty).
8954 ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
8955 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8956 /*IsAssignmentOperator=*/isEqualOp);
8957
8958 // Add this built-in operator as a candidate (VQ is 'volatile').
8959 if (VisibleTypeConversionsQuals.hasVolatile()) {
8960 ParamTypes[0] = S.Context.getVolatileType(LeftBaseTy);
8961 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
8962 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8963 /*IsAssignmentOperator=*/isEqualOp);
8964 }
8965 }
8966 }
8967
8968 // Extension: Add the binary operators =, +=, -=, *=, /= for vector types.
8969 for (QualType Vec1Ty : CandidateTypes[0].vector_types())
8970 for (QualType Vec2Ty : CandidateTypes[0].vector_types()) {
8971 QualType ParamTypes[2];
8972 ParamTypes[1] = Vec2Ty;
8973 // Add this built-in operator as a candidate (VQ is empty).
8974 ParamTypes[0] = S.Context.getLValueReferenceType(Vec1Ty);
8975 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8976 /*IsAssignmentOperator=*/isEqualOp);
8977
8978 // Add this built-in operator as a candidate (VQ is 'volatile').
8979 if (VisibleTypeConversionsQuals.hasVolatile()) {
8980 ParamTypes[0] = S.Context.getVolatileType(Vec1Ty);
8981 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
8982 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
8983 /*IsAssignmentOperator=*/isEqualOp);
8984 }
8985 }
8986 }
8987
8988 // C++ [over.built]p22:
8989 //
8990 // For every triple (L, VQ, R), where L is an integral type, VQ
8991 // is either volatile or empty, and R is a promoted integral
8992 // type, there exist candidate operator functions of the form
8993 //
8994 // VQ L& operator%=(VQ L&, R);
8995 // VQ L& operator<<=(VQ L&, R);
8996 // VQ L& operator>>=(VQ L&, R);
8997 // VQ L& operator&=(VQ L&, R);
8998 // VQ L& operator^=(VQ L&, R);
8999 // VQ L& operator|=(VQ L&, R);
addAssignmentIntegralOverloads()9000 void addAssignmentIntegralOverloads() {
9001 if (!HasArithmeticOrEnumeralCandidateType)
9002 return;
9003
9004 for (unsigned Left = FirstIntegralType; Left < LastIntegralType; ++Left) {
9005 for (unsigned Right = FirstPromotedIntegralType;
9006 Right < LastPromotedIntegralType; ++Right) {
9007 QualType ParamTypes[2];
9008 ParamTypes[1] = ArithmeticTypes[Right];
9009 auto LeftBaseTy = AdjustAddressSpaceForBuiltinOperandType(
9010 S, ArithmeticTypes[Left], Args[0]);
9011 // Add this built-in operator as a candidate (VQ is empty).
9012 ParamTypes[0] = S.Context.getLValueReferenceType(LeftBaseTy);
9013 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9014 if (VisibleTypeConversionsQuals.hasVolatile()) {
9015 // Add this built-in operator as a candidate (VQ is 'volatile').
9016 ParamTypes[0] = LeftBaseTy;
9017 ParamTypes[0] = S.Context.getVolatileType(ParamTypes[0]);
9018 ParamTypes[0] = S.Context.getLValueReferenceType(ParamTypes[0]);
9019 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9020 }
9021 }
9022 }
9023 }
9024
9025 // C++ [over.operator]p23:
9026 //
9027 // There also exist candidate operator functions of the form
9028 //
9029 // bool operator!(bool);
9030 // bool operator&&(bool, bool);
9031 // bool operator||(bool, bool);
addExclaimOverload()9032 void addExclaimOverload() {
9033 QualType ParamTy = S.Context.BoolTy;
9034 S.AddBuiltinCandidate(&ParamTy, Args, CandidateSet,
9035 /*IsAssignmentOperator=*/false,
9036 /*NumContextualBoolArguments=*/1);
9037 }
addAmpAmpOrPipePipeOverload()9038 void addAmpAmpOrPipePipeOverload() {
9039 QualType ParamTypes[2] = { S.Context.BoolTy, S.Context.BoolTy };
9040 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet,
9041 /*IsAssignmentOperator=*/false,
9042 /*NumContextualBoolArguments=*/2);
9043 }
9044
9045 // C++ [over.built]p13:
9046 //
9047 // For every cv-qualified or cv-unqualified object type T there
9048 // exist candidate operator functions of the form
9049 //
9050 // T* operator+(T*, ptrdiff_t); [ABOVE]
9051 // T& operator[](T*, ptrdiff_t);
9052 // T* operator-(T*, ptrdiff_t); [ABOVE]
9053 // T* operator+(ptrdiff_t, T*); [ABOVE]
9054 // T& operator[](ptrdiff_t, T*);
addSubscriptOverloads()9055 void addSubscriptOverloads() {
9056 for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
9057 QualType ParamTypes[2] = {PtrTy, S.Context.getPointerDiffType()};
9058 QualType PointeeType = PtrTy->getPointeeType();
9059 if (!PointeeType->isObjectType())
9060 continue;
9061
9062 // T& operator[](T*, ptrdiff_t)
9063 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9064 }
9065
9066 for (QualType PtrTy : CandidateTypes[1].pointer_types()) {
9067 QualType ParamTypes[2] = {S.Context.getPointerDiffType(), PtrTy};
9068 QualType PointeeType = PtrTy->getPointeeType();
9069 if (!PointeeType->isObjectType())
9070 continue;
9071
9072 // T& operator[](ptrdiff_t, T*)
9073 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9074 }
9075 }
9076
9077 // C++ [over.built]p11:
9078 // For every quintuple (C1, C2, T, CV1, CV2), where C2 is a class type,
9079 // C1 is the same type as C2 or is a derived class of C2, T is an object
9080 // type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
9081 // there exist candidate operator functions of the form
9082 //
9083 // CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
9084 //
9085 // where CV12 is the union of CV1 and CV2.
addArrowStarOverloads()9086 void addArrowStarOverloads() {
9087 for (QualType PtrTy : CandidateTypes[0].pointer_types()) {
9088 QualType C1Ty = PtrTy;
9089 QualType C1;
9090 QualifierCollector Q1;
9091 C1 = QualType(Q1.strip(C1Ty->getPointeeType()), 0);
9092 if (!isa<RecordType>(C1))
9093 continue;
9094 // heuristic to reduce number of builtin candidates in the set.
9095 // Add volatile/restrict version only if there are conversions to a
9096 // volatile/restrict type.
9097 if (!VisibleTypeConversionsQuals.hasVolatile() && Q1.hasVolatile())
9098 continue;
9099 if (!VisibleTypeConversionsQuals.hasRestrict() && Q1.hasRestrict())
9100 continue;
9101 for (QualType MemPtrTy : CandidateTypes[1].member_pointer_types()) {
9102 const MemberPointerType *mptr = cast<MemberPointerType>(MemPtrTy);
9103 QualType C2 = QualType(mptr->getClass(), 0);
9104 C2 = C2.getUnqualifiedType();
9105 if (C1 != C2 && !S.IsDerivedFrom(CandidateSet.getLocation(), C1, C2))
9106 break;
9107 QualType ParamTypes[2] = {PtrTy, MemPtrTy};
9108 // build CV12 T&
9109 QualType T = mptr->getPointeeType();
9110 if (!VisibleTypeConversionsQuals.hasVolatile() &&
9111 T.isVolatileQualified())
9112 continue;
9113 if (!VisibleTypeConversionsQuals.hasRestrict() &&
9114 T.isRestrictQualified())
9115 continue;
9116 T = Q1.apply(S.Context, T);
9117 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9118 }
9119 }
9120 }
9121
9122 // Note that we don't consider the first argument, since it has been
9123 // contextually converted to bool long ago. The candidates below are
9124 // therefore added as binary.
9125 //
9126 // C++ [over.built]p25:
9127 // For every type T, where T is a pointer, pointer-to-member, or scoped
9128 // enumeration type, there exist candidate operator functions of the form
9129 //
9130 // T operator?(bool, T, T);
9131 //
addConditionalOperatorOverloads()9132 void addConditionalOperatorOverloads() {
9133 /// Set of (canonical) types that we've already handled.
9134 llvm::SmallPtrSet<QualType, 8> AddedTypes;
9135
9136 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
9137 for (QualType PtrTy : CandidateTypes[ArgIdx].pointer_types()) {
9138 if (!AddedTypes.insert(S.Context.getCanonicalType(PtrTy)).second)
9139 continue;
9140
9141 QualType ParamTypes[2] = {PtrTy, PtrTy};
9142 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9143 }
9144
9145 for (QualType MemPtrTy : CandidateTypes[ArgIdx].member_pointer_types()) {
9146 if (!AddedTypes.insert(S.Context.getCanonicalType(MemPtrTy)).second)
9147 continue;
9148
9149 QualType ParamTypes[2] = {MemPtrTy, MemPtrTy};
9150 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9151 }
9152
9153 if (S.getLangOpts().CPlusPlus11) {
9154 for (QualType EnumTy : CandidateTypes[ArgIdx].enumeration_types()) {
9155 if (!EnumTy->castAs<EnumType>()->getDecl()->isScoped())
9156 continue;
9157
9158 if (!AddedTypes.insert(S.Context.getCanonicalType(EnumTy)).second)
9159 continue;
9160
9161 QualType ParamTypes[2] = {EnumTy, EnumTy};
9162 S.AddBuiltinCandidate(ParamTypes, Args, CandidateSet);
9163 }
9164 }
9165 }
9166 }
9167 };
9168
9169 } // end anonymous namespace
9170
9171 /// AddBuiltinOperatorCandidates - Add the appropriate built-in
9172 /// operator overloads to the candidate set (C++ [over.built]), based
9173 /// on the operator @p Op and the arguments given. For example, if the
9174 /// operator is a binary '+', this routine might add "int
9175 /// operator+(int, int)" to cover integer addition.
AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)9176 void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
9177 SourceLocation OpLoc,
9178 ArrayRef<Expr *> Args,
9179 OverloadCandidateSet &CandidateSet) {
9180 // Find all of the types that the arguments can convert to, but only
9181 // if the operator we're looking at has built-in operator candidates
9182 // that make use of these types. Also record whether we encounter non-record
9183 // candidate types or either arithmetic or enumeral candidate types.
9184 Qualifiers VisibleTypeConversionsQuals;
9185 VisibleTypeConversionsQuals.addConst();
9186 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx)
9187 VisibleTypeConversionsQuals += CollectVRQualifiers(Context, Args[ArgIdx]);
9188
9189 bool HasNonRecordCandidateType = false;
9190 bool HasArithmeticOrEnumeralCandidateType = false;
9191 SmallVector<BuiltinCandidateTypeSet, 2> CandidateTypes;
9192 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
9193 CandidateTypes.emplace_back(*this);
9194 CandidateTypes[ArgIdx].AddTypesConvertedFrom(Args[ArgIdx]->getType(),
9195 OpLoc,
9196 true,
9197 (Op == OO_Exclaim ||
9198 Op == OO_AmpAmp ||
9199 Op == OO_PipePipe),
9200 VisibleTypeConversionsQuals);
9201 HasNonRecordCandidateType = HasNonRecordCandidateType ||
9202 CandidateTypes[ArgIdx].hasNonRecordTypes();
9203 HasArithmeticOrEnumeralCandidateType =
9204 HasArithmeticOrEnumeralCandidateType ||
9205 CandidateTypes[ArgIdx].hasArithmeticOrEnumeralTypes();
9206 }
9207
9208 // Exit early when no non-record types have been added to the candidate set
9209 // for any of the arguments to the operator.
9210 //
9211 // We can't exit early for !, ||, or &&, since there we have always have
9212 // 'bool' overloads.
9213 if (!HasNonRecordCandidateType &&
9214 !(Op == OO_Exclaim || Op == OO_AmpAmp || Op == OO_PipePipe))
9215 return;
9216
9217 // Setup an object to manage the common state for building overloads.
9218 BuiltinOperatorOverloadBuilder OpBuilder(*this, Args,
9219 VisibleTypeConversionsQuals,
9220 HasArithmeticOrEnumeralCandidateType,
9221 CandidateTypes, CandidateSet);
9222
9223 // Dispatch over the operation to add in only those overloads which apply.
9224 switch (Op) {
9225 case OO_None:
9226 case NUM_OVERLOADED_OPERATORS:
9227 llvm_unreachable("Expected an overloaded operator");
9228
9229 case OO_New:
9230 case OO_Delete:
9231 case OO_Array_New:
9232 case OO_Array_Delete:
9233 case OO_Call:
9234 llvm_unreachable(
9235 "Special operators don't use AddBuiltinOperatorCandidates");
9236
9237 case OO_Comma:
9238 case OO_Arrow:
9239 case OO_Coawait:
9240 // C++ [over.match.oper]p3:
9241 // -- For the operator ',', the unary operator '&', the
9242 // operator '->', or the operator 'co_await', the
9243 // built-in candidates set is empty.
9244 break;
9245
9246 case OO_Plus: // '+' is either unary or binary
9247 if (Args.size() == 1)
9248 OpBuilder.addUnaryPlusPointerOverloads();
9249 LLVM_FALLTHROUGH;
9250
9251 case OO_Minus: // '-' is either unary or binary
9252 if (Args.size() == 1) {
9253 OpBuilder.addUnaryPlusOrMinusArithmeticOverloads();
9254 } else {
9255 OpBuilder.addBinaryPlusOrMinusPointerOverloads(Op);
9256 OpBuilder.addGenericBinaryArithmeticOverloads();
9257 OpBuilder.addMatrixBinaryArithmeticOverloads();
9258 }
9259 break;
9260
9261 case OO_Star: // '*' is either unary or binary
9262 if (Args.size() == 1)
9263 OpBuilder.addUnaryStarPointerOverloads();
9264 else {
9265 OpBuilder.addGenericBinaryArithmeticOverloads();
9266 OpBuilder.addMatrixBinaryArithmeticOverloads();
9267 }
9268 break;
9269
9270 case OO_Slash:
9271 OpBuilder.addGenericBinaryArithmeticOverloads();
9272 break;
9273
9274 case OO_PlusPlus:
9275 case OO_MinusMinus:
9276 OpBuilder.addPlusPlusMinusMinusArithmeticOverloads(Op);
9277 OpBuilder.addPlusPlusMinusMinusPointerOverloads();
9278 break;
9279
9280 case OO_EqualEqual:
9281 case OO_ExclaimEqual:
9282 OpBuilder.addEqualEqualOrNotEqualMemberPointerOrNullptrOverloads();
9283 OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
9284 OpBuilder.addGenericBinaryArithmeticOverloads();
9285 break;
9286
9287 case OO_Less:
9288 case OO_Greater:
9289 case OO_LessEqual:
9290 case OO_GreaterEqual:
9291 OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/false);
9292 OpBuilder.addGenericBinaryArithmeticOverloads();
9293 break;
9294
9295 case OO_Spaceship:
9296 OpBuilder.addGenericBinaryPointerOrEnumeralOverloads(/*IsSpaceship=*/true);
9297 OpBuilder.addThreeWayArithmeticOverloads();
9298 break;
9299
9300 case OO_Percent:
9301 case OO_Caret:
9302 case OO_Pipe:
9303 case OO_LessLess:
9304 case OO_GreaterGreater:
9305 OpBuilder.addBinaryBitwiseArithmeticOverloads();
9306 break;
9307
9308 case OO_Amp: // '&' is either unary or binary
9309 if (Args.size() == 1)
9310 // C++ [over.match.oper]p3:
9311 // -- For the operator ',', the unary operator '&', or the
9312 // operator '->', the built-in candidates set is empty.
9313 break;
9314
9315 OpBuilder.addBinaryBitwiseArithmeticOverloads();
9316 break;
9317
9318 case OO_Tilde:
9319 OpBuilder.addUnaryTildePromotedIntegralOverloads();
9320 break;
9321
9322 case OO_Equal:
9323 OpBuilder.addAssignmentMemberPointerOrEnumeralOverloads();
9324 LLVM_FALLTHROUGH;
9325
9326 case OO_PlusEqual:
9327 case OO_MinusEqual:
9328 OpBuilder.addAssignmentPointerOverloads(Op == OO_Equal);
9329 LLVM_FALLTHROUGH;
9330
9331 case OO_StarEqual:
9332 case OO_SlashEqual:
9333 OpBuilder.addAssignmentArithmeticOverloads(Op == OO_Equal);
9334 break;
9335
9336 case OO_PercentEqual:
9337 case OO_LessLessEqual:
9338 case OO_GreaterGreaterEqual:
9339 case OO_AmpEqual:
9340 case OO_CaretEqual:
9341 case OO_PipeEqual:
9342 OpBuilder.addAssignmentIntegralOverloads();
9343 break;
9344
9345 case OO_Exclaim:
9346 OpBuilder.addExclaimOverload();
9347 break;
9348
9349 case OO_AmpAmp:
9350 case OO_PipePipe:
9351 OpBuilder.addAmpAmpOrPipePipeOverload();
9352 break;
9353
9354 case OO_Subscript:
9355 OpBuilder.addSubscriptOverloads();
9356 break;
9357
9358 case OO_ArrowStar:
9359 OpBuilder.addArrowStarOverloads();
9360 break;
9361
9362 case OO_Conditional:
9363 OpBuilder.addConditionalOperatorOverloads();
9364 OpBuilder.addGenericBinaryArithmeticOverloads();
9365 break;
9366 }
9367 }
9368
9369 /// Add function candidates found via argument-dependent lookup
9370 /// to the set of overloading candidates.
9371 ///
9372 /// This routine performs argument-dependent name lookup based on the
9373 /// given function name (which may also be an operator name) and adds
9374 /// all of the overload candidates found by ADL to the overload
9375 /// candidate set (C++ [basic.lookup.argdep]).
9376 void
AddArgumentDependentLookupCandidates(DeclarationName Name,SourceLocation Loc,ArrayRef<Expr * > Args,TemplateArgumentListInfo * ExplicitTemplateArgs,OverloadCandidateSet & CandidateSet,bool PartialOverloading)9377 Sema::AddArgumentDependentLookupCandidates(DeclarationName Name,
9378 SourceLocation Loc,
9379 ArrayRef<Expr *> Args,
9380 TemplateArgumentListInfo *ExplicitTemplateArgs,
9381 OverloadCandidateSet& CandidateSet,
9382 bool PartialOverloading) {
9383 ADLResult Fns;
9384
9385 // FIXME: This approach for uniquing ADL results (and removing
9386 // redundant candidates from the set) relies on pointer-equality,
9387 // which means we need to key off the canonical decl. However,
9388 // always going back to the canonical decl might not get us the
9389 // right set of default arguments. What default arguments are
9390 // we supposed to consider on ADL candidates, anyway?
9391
9392 // FIXME: Pass in the explicit template arguments?
9393 ArgumentDependentLookup(Name, Loc, Args, Fns);
9394
9395 // Erase all of the candidates we already knew about.
9396 for (OverloadCandidateSet::iterator Cand = CandidateSet.begin(),
9397 CandEnd = CandidateSet.end();
9398 Cand != CandEnd; ++Cand)
9399 if (Cand->Function) {
9400 Fns.erase(Cand->Function);
9401 if (FunctionTemplateDecl *FunTmpl = Cand->Function->getPrimaryTemplate())
9402 Fns.erase(FunTmpl);
9403 }
9404
9405 // For each of the ADL candidates we found, add it to the overload
9406 // set.
9407 for (ADLResult::iterator I = Fns.begin(), E = Fns.end(); I != E; ++I) {
9408 DeclAccessPair FoundDecl = DeclAccessPair::make(*I, AS_none);
9409
9410 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*I)) {
9411 if (ExplicitTemplateArgs)
9412 continue;
9413
9414 AddOverloadCandidate(
9415 FD, FoundDecl, Args, CandidateSet, /*SuppressUserConversions=*/false,
9416 PartialOverloading, /*AllowExplicit=*/true,
9417 /*AllowExplicitConversions=*/false, ADLCallKind::UsesADL);
9418 if (CandidateSet.getRewriteInfo().shouldAddReversed(Context, FD)) {
9419 AddOverloadCandidate(
9420 FD, FoundDecl, {Args[1], Args[0]}, CandidateSet,
9421 /*SuppressUserConversions=*/false, PartialOverloading,
9422 /*AllowExplicit=*/true, /*AllowExplicitConversions=*/false,
9423 ADLCallKind::UsesADL, None, OverloadCandidateParamOrder::Reversed);
9424 }
9425 } else {
9426 auto *FTD = cast<FunctionTemplateDecl>(*I);
9427 AddTemplateOverloadCandidate(
9428 FTD, FoundDecl, ExplicitTemplateArgs, Args, CandidateSet,
9429 /*SuppressUserConversions=*/false, PartialOverloading,
9430 /*AllowExplicit=*/true, ADLCallKind::UsesADL);
9431 if (CandidateSet.getRewriteInfo().shouldAddReversed(
9432 Context, FTD->getTemplatedDecl())) {
9433 AddTemplateOverloadCandidate(
9434 FTD, FoundDecl, ExplicitTemplateArgs, {Args[1], Args[0]},
9435 CandidateSet, /*SuppressUserConversions=*/false, PartialOverloading,
9436 /*AllowExplicit=*/true, ADLCallKind::UsesADL,
9437 OverloadCandidateParamOrder::Reversed);
9438 }
9439 }
9440 }
9441 }
9442
9443 namespace {
9444 enum class Comparison { Equal, Better, Worse };
9445 }
9446
9447 /// Compares the enable_if attributes of two FunctionDecls, for the purposes of
9448 /// overload resolution.
9449 ///
9450 /// Cand1's set of enable_if attributes are said to be "better" than Cand2's iff
9451 /// Cand1's first N enable_if attributes have precisely the same conditions as
9452 /// Cand2's first N enable_if attributes (where N = the number of enable_if
9453 /// attributes on Cand2), and Cand1 has more than N enable_if attributes.
9454 ///
9455 /// Note that you can have a pair of candidates such that Cand1's enable_if
9456 /// attributes are worse than Cand2's, and Cand2's enable_if attributes are
9457 /// worse than Cand1's.
compareEnableIfAttrs(const Sema & S,const FunctionDecl * Cand1,const FunctionDecl * Cand2)9458 static Comparison compareEnableIfAttrs(const Sema &S, const FunctionDecl *Cand1,
9459 const FunctionDecl *Cand2) {
9460 // Common case: One (or both) decls don't have enable_if attrs.
9461 bool Cand1Attr = Cand1->hasAttr<EnableIfAttr>();
9462 bool Cand2Attr = Cand2->hasAttr<EnableIfAttr>();
9463 if (!Cand1Attr || !Cand2Attr) {
9464 if (Cand1Attr == Cand2Attr)
9465 return Comparison::Equal;
9466 return Cand1Attr ? Comparison::Better : Comparison::Worse;
9467 }
9468
9469 auto Cand1Attrs = Cand1->specific_attrs<EnableIfAttr>();
9470 auto Cand2Attrs = Cand2->specific_attrs<EnableIfAttr>();
9471
9472 llvm::FoldingSetNodeID Cand1ID, Cand2ID;
9473 for (auto Pair : zip_longest(Cand1Attrs, Cand2Attrs)) {
9474 Optional<EnableIfAttr *> Cand1A = std::get<0>(Pair);
9475 Optional<EnableIfAttr *> Cand2A = std::get<1>(Pair);
9476
9477 // It's impossible for Cand1 to be better than (or equal to) Cand2 if Cand1
9478 // has fewer enable_if attributes than Cand2, and vice versa.
9479 if (!Cand1A)
9480 return Comparison::Worse;
9481 if (!Cand2A)
9482 return Comparison::Better;
9483
9484 Cand1ID.clear();
9485 Cand2ID.clear();
9486
9487 (*Cand1A)->getCond()->Profile(Cand1ID, S.getASTContext(), true);
9488 (*Cand2A)->getCond()->Profile(Cand2ID, S.getASTContext(), true);
9489 if (Cand1ID != Cand2ID)
9490 return Comparison::Worse;
9491 }
9492
9493 return Comparison::Equal;
9494 }
9495
9496 static Comparison
isBetterMultiversionCandidate(const OverloadCandidate & Cand1,const OverloadCandidate & Cand2)9497 isBetterMultiversionCandidate(const OverloadCandidate &Cand1,
9498 const OverloadCandidate &Cand2) {
9499 if (!Cand1.Function || !Cand1.Function->isMultiVersion() || !Cand2.Function ||
9500 !Cand2.Function->isMultiVersion())
9501 return Comparison::Equal;
9502
9503 // If both are invalid, they are equal. If one of them is invalid, the other
9504 // is better.
9505 if (Cand1.Function->isInvalidDecl()) {
9506 if (Cand2.Function->isInvalidDecl())
9507 return Comparison::Equal;
9508 return Comparison::Worse;
9509 }
9510 if (Cand2.Function->isInvalidDecl())
9511 return Comparison::Better;
9512
9513 // If this is a cpu_dispatch/cpu_specific multiversion situation, prefer
9514 // cpu_dispatch, else arbitrarily based on the identifiers.
9515 bool Cand1CPUDisp = Cand1.Function->hasAttr<CPUDispatchAttr>();
9516 bool Cand2CPUDisp = Cand2.Function->hasAttr<CPUDispatchAttr>();
9517 const auto *Cand1CPUSpec = Cand1.Function->getAttr<CPUSpecificAttr>();
9518 const auto *Cand2CPUSpec = Cand2.Function->getAttr<CPUSpecificAttr>();
9519
9520 if (!Cand1CPUDisp && !Cand2CPUDisp && !Cand1CPUSpec && !Cand2CPUSpec)
9521 return Comparison::Equal;
9522
9523 if (Cand1CPUDisp && !Cand2CPUDisp)
9524 return Comparison::Better;
9525 if (Cand2CPUDisp && !Cand1CPUDisp)
9526 return Comparison::Worse;
9527
9528 if (Cand1CPUSpec && Cand2CPUSpec) {
9529 if (Cand1CPUSpec->cpus_size() != Cand2CPUSpec->cpus_size())
9530 return Cand1CPUSpec->cpus_size() < Cand2CPUSpec->cpus_size()
9531 ? Comparison::Better
9532 : Comparison::Worse;
9533
9534 std::pair<CPUSpecificAttr::cpus_iterator, CPUSpecificAttr::cpus_iterator>
9535 FirstDiff = std::mismatch(
9536 Cand1CPUSpec->cpus_begin(), Cand1CPUSpec->cpus_end(),
9537 Cand2CPUSpec->cpus_begin(),
9538 [](const IdentifierInfo *LHS, const IdentifierInfo *RHS) {
9539 return LHS->getName() == RHS->getName();
9540 });
9541
9542 assert(FirstDiff.first != Cand1CPUSpec->cpus_end() &&
9543 "Two different cpu-specific versions should not have the same "
9544 "identifier list, otherwise they'd be the same decl!");
9545 return (*FirstDiff.first)->getName() < (*FirstDiff.second)->getName()
9546 ? Comparison::Better
9547 : Comparison::Worse;
9548 }
9549 llvm_unreachable("No way to get here unless both had cpu_dispatch");
9550 }
9551
9552 /// Compute the type of the implicit object parameter for the given function,
9553 /// if any. Returns None if there is no implicit object parameter, and a null
9554 /// QualType if there is a 'matches anything' implicit object parameter.
getImplicitObjectParamType(ASTContext & Context,const FunctionDecl * F)9555 static Optional<QualType> getImplicitObjectParamType(ASTContext &Context,
9556 const FunctionDecl *F) {
9557 if (!isa<CXXMethodDecl>(F) || isa<CXXConstructorDecl>(F))
9558 return llvm::None;
9559
9560 auto *M = cast<CXXMethodDecl>(F);
9561 // Static member functions' object parameters match all types.
9562 if (M->isStatic())
9563 return QualType();
9564
9565 QualType T = M->getThisObjectType();
9566 if (M->getRefQualifier() == RQ_RValue)
9567 return Context.getRValueReferenceType(T);
9568 return Context.getLValueReferenceType(T);
9569 }
9570
haveSameParameterTypes(ASTContext & Context,const FunctionDecl * F1,const FunctionDecl * F2,unsigned NumParams)9571 static bool haveSameParameterTypes(ASTContext &Context, const FunctionDecl *F1,
9572 const FunctionDecl *F2, unsigned NumParams) {
9573 if (declaresSameEntity(F1, F2))
9574 return true;
9575
9576 auto NextParam = [&](const FunctionDecl *F, unsigned &I, bool First) {
9577 if (First) {
9578 if (Optional<QualType> T = getImplicitObjectParamType(Context, F))
9579 return *T;
9580 }
9581 assert(I < F->getNumParams());
9582 return F->getParamDecl(I++)->getType();
9583 };
9584
9585 unsigned I1 = 0, I2 = 0;
9586 for (unsigned I = 0; I != NumParams; ++I) {
9587 QualType T1 = NextParam(F1, I1, I == 0);
9588 QualType T2 = NextParam(F2, I2, I == 0);
9589 if (!T1.isNull() && !T1.isNull() && !Context.hasSameUnqualifiedType(T1, T2))
9590 return false;
9591 }
9592 return true;
9593 }
9594
9595 /// isBetterOverloadCandidate - Determines whether the first overload
9596 /// candidate is a better candidate than the second (C++ 13.3.3p1).
isBetterOverloadCandidate(Sema & S,const OverloadCandidate & Cand1,const OverloadCandidate & Cand2,SourceLocation Loc,OverloadCandidateSet::CandidateSetKind Kind)9597 bool clang::isBetterOverloadCandidate(
9598 Sema &S, const OverloadCandidate &Cand1, const OverloadCandidate &Cand2,
9599 SourceLocation Loc, OverloadCandidateSet::CandidateSetKind Kind) {
9600 // Define viable functions to be better candidates than non-viable
9601 // functions.
9602 if (!Cand2.Viable)
9603 return Cand1.Viable;
9604 else if (!Cand1.Viable)
9605 return false;
9606
9607 // [CUDA] A function with 'never' preference is marked not viable, therefore
9608 // is never shown up here. The worst preference shown up here is 'wrong side',
9609 // e.g. an H function called by a HD function in device compilation. This is
9610 // valid AST as long as the HD function is not emitted, e.g. it is an inline
9611 // function which is called only by an H function. A deferred diagnostic will
9612 // be triggered if it is emitted. However a wrong-sided function is still
9613 // a viable candidate here.
9614 //
9615 // If Cand1 can be emitted and Cand2 cannot be emitted in the current
9616 // context, Cand1 is better than Cand2. If Cand1 can not be emitted and Cand2
9617 // can be emitted, Cand1 is not better than Cand2. This rule should have
9618 // precedence over other rules.
9619 //
9620 // If both Cand1 and Cand2 can be emitted, or neither can be emitted, then
9621 // other rules should be used to determine which is better. This is because
9622 // host/device based overloading resolution is mostly for determining
9623 // viability of a function. If two functions are both viable, other factors
9624 // should take precedence in preference, e.g. the standard-defined preferences
9625 // like argument conversion ranks or enable_if partial-ordering. The
9626 // preference for pass-object-size parameters is probably most similar to a
9627 // type-based-overloading decision and so should take priority.
9628 //
9629 // If other rules cannot determine which is better, CUDA preference will be
9630 // used again to determine which is better.
9631 //
9632 // TODO: Currently IdentifyCUDAPreference does not return correct values
9633 // for functions called in global variable initializers due to missing
9634 // correct context about device/host. Therefore we can only enforce this
9635 // rule when there is a caller. We should enforce this rule for functions
9636 // in global variable initializers once proper context is added.
9637 //
9638 // TODO: We can only enable the hostness based overloading resolution when
9639 // -fgpu-exclude-wrong-side-overloads is on since this requires deferring
9640 // overloading resolution diagnostics.
9641 if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function &&
9642 S.getLangOpts().GPUExcludeWrongSideOverloads) {
9643 if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext)) {
9644 bool IsCallerImplicitHD = Sema::isCUDAImplicitHostDeviceFunction(Caller);
9645 bool IsCand1ImplicitHD =
9646 Sema::isCUDAImplicitHostDeviceFunction(Cand1.Function);
9647 bool IsCand2ImplicitHD =
9648 Sema::isCUDAImplicitHostDeviceFunction(Cand2.Function);
9649 auto P1 = S.IdentifyCUDAPreference(Caller, Cand1.Function);
9650 auto P2 = S.IdentifyCUDAPreference(Caller, Cand2.Function);
9651 assert(P1 != Sema::CFP_Never && P2 != Sema::CFP_Never);
9652 // The implicit HD function may be a function in a system header which
9653 // is forced by pragma. In device compilation, if we prefer HD candidates
9654 // over wrong-sided candidates, overloading resolution may change, which
9655 // may result in non-deferrable diagnostics. As a workaround, we let
9656 // implicit HD candidates take equal preference as wrong-sided candidates.
9657 // This will preserve the overloading resolution.
9658 // TODO: We still need special handling of implicit HD functions since
9659 // they may incur other diagnostics to be deferred. We should make all
9660 // host/device related diagnostics deferrable and remove special handling
9661 // of implicit HD functions.
9662 auto EmitThreshold =
9663 (S.getLangOpts().CUDAIsDevice && IsCallerImplicitHD &&
9664 (IsCand1ImplicitHD || IsCand2ImplicitHD))
9665 ? Sema::CFP_Never
9666 : Sema::CFP_WrongSide;
9667 auto Cand1Emittable = P1 > EmitThreshold;
9668 auto Cand2Emittable = P2 > EmitThreshold;
9669 if (Cand1Emittable && !Cand2Emittable)
9670 return true;
9671 if (!Cand1Emittable && Cand2Emittable)
9672 return false;
9673 }
9674 }
9675
9676 // C++ [over.match.best]p1:
9677 //
9678 // -- if F is a static member function, ICS1(F) is defined such
9679 // that ICS1(F) is neither better nor worse than ICS1(G) for
9680 // any function G, and, symmetrically, ICS1(G) is neither
9681 // better nor worse than ICS1(F).
9682 unsigned StartArg = 0;
9683 if (Cand1.IgnoreObjectArgument || Cand2.IgnoreObjectArgument)
9684 StartArg = 1;
9685
9686 auto IsIllFormedConversion = [&](const ImplicitConversionSequence &ICS) {
9687 // We don't allow incompatible pointer conversions in C++.
9688 if (!S.getLangOpts().CPlusPlus)
9689 return ICS.isStandard() &&
9690 ICS.Standard.Second == ICK_Incompatible_Pointer_Conversion;
9691
9692 // The only ill-formed conversion we allow in C++ is the string literal to
9693 // char* conversion, which is only considered ill-formed after C++11.
9694 return S.getLangOpts().CPlusPlus11 && !S.getLangOpts().WritableStrings &&
9695 hasDeprecatedStringLiteralToCharPtrConversion(ICS);
9696 };
9697
9698 // Define functions that don't require ill-formed conversions for a given
9699 // argument to be better candidates than functions that do.
9700 unsigned NumArgs = Cand1.Conversions.size();
9701 assert(Cand2.Conversions.size() == NumArgs && "Overload candidate mismatch");
9702 bool HasBetterConversion = false;
9703 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
9704 bool Cand1Bad = IsIllFormedConversion(Cand1.Conversions[ArgIdx]);
9705 bool Cand2Bad = IsIllFormedConversion(Cand2.Conversions[ArgIdx]);
9706 if (Cand1Bad != Cand2Bad) {
9707 if (Cand1Bad)
9708 return false;
9709 HasBetterConversion = true;
9710 }
9711 }
9712
9713 if (HasBetterConversion)
9714 return true;
9715
9716 // C++ [over.match.best]p1:
9717 // A viable function F1 is defined to be a better function than another
9718 // viable function F2 if for all arguments i, ICSi(F1) is not a worse
9719 // conversion sequence than ICSi(F2), and then...
9720 bool HasWorseConversion = false;
9721 for (unsigned ArgIdx = StartArg; ArgIdx < NumArgs; ++ArgIdx) {
9722 switch (CompareImplicitConversionSequences(S, Loc,
9723 Cand1.Conversions[ArgIdx],
9724 Cand2.Conversions[ArgIdx])) {
9725 case ImplicitConversionSequence::Better:
9726 // Cand1 has a better conversion sequence.
9727 HasBetterConversion = true;
9728 break;
9729
9730 case ImplicitConversionSequence::Worse:
9731 if (Cand1.Function && Cand2.Function &&
9732 Cand1.isReversed() != Cand2.isReversed() &&
9733 haveSameParameterTypes(S.Context, Cand1.Function, Cand2.Function,
9734 NumArgs)) {
9735 // Work around large-scale breakage caused by considering reversed
9736 // forms of operator== in C++20:
9737 //
9738 // When comparing a function against a reversed function with the same
9739 // parameter types, if we have a better conversion for one argument and
9740 // a worse conversion for the other, the implicit conversion sequences
9741 // are treated as being equally good.
9742 //
9743 // This prevents a comparison function from being considered ambiguous
9744 // with a reversed form that is written in the same way.
9745 //
9746 // We diagnose this as an extension from CreateOverloadedBinOp.
9747 HasWorseConversion = true;
9748 break;
9749 }
9750
9751 // Cand1 can't be better than Cand2.
9752 return false;
9753
9754 case ImplicitConversionSequence::Indistinguishable:
9755 // Do nothing.
9756 break;
9757 }
9758 }
9759
9760 // -- for some argument j, ICSj(F1) is a better conversion sequence than
9761 // ICSj(F2), or, if not that,
9762 if (HasBetterConversion && !HasWorseConversion)
9763 return true;
9764
9765 // -- the context is an initialization by user-defined conversion
9766 // (see 8.5, 13.3.1.5) and the standard conversion sequence
9767 // from the return type of F1 to the destination type (i.e.,
9768 // the type of the entity being initialized) is a better
9769 // conversion sequence than the standard conversion sequence
9770 // from the return type of F2 to the destination type.
9771 if (Kind == OverloadCandidateSet::CSK_InitByUserDefinedConversion &&
9772 Cand1.Function && Cand2.Function &&
9773 isa<CXXConversionDecl>(Cand1.Function) &&
9774 isa<CXXConversionDecl>(Cand2.Function)) {
9775 // First check whether we prefer one of the conversion functions over the
9776 // other. This only distinguishes the results in non-standard, extension
9777 // cases such as the conversion from a lambda closure type to a function
9778 // pointer or block.
9779 ImplicitConversionSequence::CompareKind Result =
9780 compareConversionFunctions(S, Cand1.Function, Cand2.Function);
9781 if (Result == ImplicitConversionSequence::Indistinguishable)
9782 Result = CompareStandardConversionSequences(S, Loc,
9783 Cand1.FinalConversion,
9784 Cand2.FinalConversion);
9785
9786 if (Result != ImplicitConversionSequence::Indistinguishable)
9787 return Result == ImplicitConversionSequence::Better;
9788
9789 // FIXME: Compare kind of reference binding if conversion functions
9790 // convert to a reference type used in direct reference binding, per
9791 // C++14 [over.match.best]p1 section 2 bullet 3.
9792 }
9793
9794 // FIXME: Work around a defect in the C++17 guaranteed copy elision wording,
9795 // as combined with the resolution to CWG issue 243.
9796 //
9797 // When the context is initialization by constructor ([over.match.ctor] or
9798 // either phase of [over.match.list]), a constructor is preferred over
9799 // a conversion function.
9800 if (Kind == OverloadCandidateSet::CSK_InitByConstructor && NumArgs == 1 &&
9801 Cand1.Function && Cand2.Function &&
9802 isa<CXXConstructorDecl>(Cand1.Function) !=
9803 isa<CXXConstructorDecl>(Cand2.Function))
9804 return isa<CXXConstructorDecl>(Cand1.Function);
9805
9806 // -- F1 is a non-template function and F2 is a function template
9807 // specialization, or, if not that,
9808 bool Cand1IsSpecialization = Cand1.Function &&
9809 Cand1.Function->getPrimaryTemplate();
9810 bool Cand2IsSpecialization = Cand2.Function &&
9811 Cand2.Function->getPrimaryTemplate();
9812 if (Cand1IsSpecialization != Cand2IsSpecialization)
9813 return Cand2IsSpecialization;
9814
9815 // -- F1 and F2 are function template specializations, and the function
9816 // template for F1 is more specialized than the template for F2
9817 // according to the partial ordering rules described in 14.5.5.2, or,
9818 // if not that,
9819 if (Cand1IsSpecialization && Cand2IsSpecialization) {
9820 if (FunctionTemplateDecl *BetterTemplate = S.getMoreSpecializedTemplate(
9821 Cand1.Function->getPrimaryTemplate(),
9822 Cand2.Function->getPrimaryTemplate(), Loc,
9823 isa<CXXConversionDecl>(Cand1.Function) ? TPOC_Conversion
9824 : TPOC_Call,
9825 Cand1.ExplicitCallArguments, Cand2.ExplicitCallArguments,
9826 Cand1.isReversed() ^ Cand2.isReversed()))
9827 return BetterTemplate == Cand1.Function->getPrimaryTemplate();
9828 }
9829
9830 // -— F1 and F2 are non-template functions with the same
9831 // parameter-type-lists, and F1 is more constrained than F2 [...],
9832 if (Cand1.Function && Cand2.Function && !Cand1IsSpecialization &&
9833 !Cand2IsSpecialization && Cand1.Function->hasPrototype() &&
9834 Cand2.Function->hasPrototype()) {
9835 auto *PT1 = cast<FunctionProtoType>(Cand1.Function->getFunctionType());
9836 auto *PT2 = cast<FunctionProtoType>(Cand2.Function->getFunctionType());
9837 if (PT1->getNumParams() == PT2->getNumParams() &&
9838 PT1->isVariadic() == PT2->isVariadic() &&
9839 S.FunctionParamTypesAreEqual(PT1, PT2)) {
9840 Expr *RC1 = Cand1.Function->getTrailingRequiresClause();
9841 Expr *RC2 = Cand2.Function->getTrailingRequiresClause();
9842 if (RC1 && RC2) {
9843 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
9844 if (S.IsAtLeastAsConstrained(Cand1.Function, {RC1}, Cand2.Function,
9845 {RC2}, AtLeastAsConstrained1) ||
9846 S.IsAtLeastAsConstrained(Cand2.Function, {RC2}, Cand1.Function,
9847 {RC1}, AtLeastAsConstrained2))
9848 return false;
9849 if (AtLeastAsConstrained1 != AtLeastAsConstrained2)
9850 return AtLeastAsConstrained1;
9851 } else if (RC1 || RC2) {
9852 return RC1 != nullptr;
9853 }
9854 }
9855 }
9856
9857 // -- F1 is a constructor for a class D, F2 is a constructor for a base
9858 // class B of D, and for all arguments the corresponding parameters of
9859 // F1 and F2 have the same type.
9860 // FIXME: Implement the "all parameters have the same type" check.
9861 bool Cand1IsInherited =
9862 dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand1.FoundDecl.getDecl());
9863 bool Cand2IsInherited =
9864 dyn_cast_or_null<ConstructorUsingShadowDecl>(Cand2.FoundDecl.getDecl());
9865 if (Cand1IsInherited != Cand2IsInherited)
9866 return Cand2IsInherited;
9867 else if (Cand1IsInherited) {
9868 assert(Cand2IsInherited);
9869 auto *Cand1Class = cast<CXXRecordDecl>(Cand1.Function->getDeclContext());
9870 auto *Cand2Class = cast<CXXRecordDecl>(Cand2.Function->getDeclContext());
9871 if (Cand1Class->isDerivedFrom(Cand2Class))
9872 return true;
9873 if (Cand2Class->isDerivedFrom(Cand1Class))
9874 return false;
9875 // Inherited from sibling base classes: still ambiguous.
9876 }
9877
9878 // -- F2 is a rewritten candidate (12.4.1.2) and F1 is not
9879 // -- F1 and F2 are rewritten candidates, and F2 is a synthesized candidate
9880 // with reversed order of parameters and F1 is not
9881 //
9882 // We rank reversed + different operator as worse than just reversed, but
9883 // that comparison can never happen, because we only consider reversing for
9884 // the maximally-rewritten operator (== or <=>).
9885 if (Cand1.RewriteKind != Cand2.RewriteKind)
9886 return Cand1.RewriteKind < Cand2.RewriteKind;
9887
9888 // Check C++17 tie-breakers for deduction guides.
9889 {
9890 auto *Guide1 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand1.Function);
9891 auto *Guide2 = dyn_cast_or_null<CXXDeductionGuideDecl>(Cand2.Function);
9892 if (Guide1 && Guide2) {
9893 // -- F1 is generated from a deduction-guide and F2 is not
9894 if (Guide1->isImplicit() != Guide2->isImplicit())
9895 return Guide2->isImplicit();
9896
9897 // -- F1 is the copy deduction candidate(16.3.1.8) and F2 is not
9898 if (Guide1->isCopyDeductionCandidate())
9899 return true;
9900 }
9901 }
9902
9903 // Check for enable_if value-based overload resolution.
9904 if (Cand1.Function && Cand2.Function) {
9905 Comparison Cmp = compareEnableIfAttrs(S, Cand1.Function, Cand2.Function);
9906 if (Cmp != Comparison::Equal)
9907 return Cmp == Comparison::Better;
9908 }
9909
9910 bool HasPS1 = Cand1.Function != nullptr &&
9911 functionHasPassObjectSizeParams(Cand1.Function);
9912 bool HasPS2 = Cand2.Function != nullptr &&
9913 functionHasPassObjectSizeParams(Cand2.Function);
9914 if (HasPS1 != HasPS2 && HasPS1)
9915 return true;
9916
9917 auto MV = isBetterMultiversionCandidate(Cand1, Cand2);
9918 if (MV == Comparison::Better)
9919 return true;
9920 if (MV == Comparison::Worse)
9921 return false;
9922
9923 // If other rules cannot determine which is better, CUDA preference is used
9924 // to determine which is better.
9925 if (S.getLangOpts().CUDA && Cand1.Function && Cand2.Function) {
9926 FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
9927 return S.IdentifyCUDAPreference(Caller, Cand1.Function) >
9928 S.IdentifyCUDAPreference(Caller, Cand2.Function);
9929 }
9930
9931 // General member function overloading is handled above, so this only handles
9932 // constructors with address spaces.
9933 // This only handles address spaces since C++ has no other
9934 // qualifier that can be used with constructors.
9935 const auto *CD1 = dyn_cast_or_null<CXXConstructorDecl>(Cand1.Function);
9936 const auto *CD2 = dyn_cast_or_null<CXXConstructorDecl>(Cand2.Function);
9937 if (CD1 && CD2) {
9938 LangAS AS1 = CD1->getMethodQualifiers().getAddressSpace();
9939 LangAS AS2 = CD2->getMethodQualifiers().getAddressSpace();
9940 if (AS1 != AS2) {
9941 if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
9942 return true;
9943 if (Qualifiers::isAddressSpaceSupersetOf(AS2, AS1))
9944 return false;
9945 }
9946 }
9947
9948 return false;
9949 }
9950
9951 /// Determine whether two declarations are "equivalent" for the purposes of
9952 /// name lookup and overload resolution. This applies when the same internal/no
9953 /// linkage entity is defined by two modules (probably by textually including
9954 /// the same header). In such a case, we don't consider the declarations to
9955 /// declare the same entity, but we also don't want lookups with both
9956 /// declarations visible to be ambiguous in some cases (this happens when using
9957 /// a modularized libstdc++).
isEquivalentInternalLinkageDeclaration(const NamedDecl * A,const NamedDecl * B)9958 bool Sema::isEquivalentInternalLinkageDeclaration(const NamedDecl *A,
9959 const NamedDecl *B) {
9960 auto *VA = dyn_cast_or_null<ValueDecl>(A);
9961 auto *VB = dyn_cast_or_null<ValueDecl>(B);
9962 if (!VA || !VB)
9963 return false;
9964
9965 // The declarations must be declaring the same name as an internal linkage
9966 // entity in different modules.
9967 if (!VA->getDeclContext()->getRedeclContext()->Equals(
9968 VB->getDeclContext()->getRedeclContext()) ||
9969 getOwningModule(VA) == getOwningModule(VB) ||
9970 VA->isExternallyVisible() || VB->isExternallyVisible())
9971 return false;
9972
9973 // Check that the declarations appear to be equivalent.
9974 //
9975 // FIXME: Checking the type isn't really enough to resolve the ambiguity.
9976 // For constants and functions, we should check the initializer or body is
9977 // the same. For non-constant variables, we shouldn't allow it at all.
9978 if (Context.hasSameType(VA->getType(), VB->getType()))
9979 return true;
9980
9981 // Enum constants within unnamed enumerations will have different types, but
9982 // may still be similar enough to be interchangeable for our purposes.
9983 if (auto *EA = dyn_cast<EnumConstantDecl>(VA)) {
9984 if (auto *EB = dyn_cast<EnumConstantDecl>(VB)) {
9985 // Only handle anonymous enums. If the enumerations were named and
9986 // equivalent, they would have been merged to the same type.
9987 auto *EnumA = cast<EnumDecl>(EA->getDeclContext());
9988 auto *EnumB = cast<EnumDecl>(EB->getDeclContext());
9989 if (EnumA->hasNameForLinkage() || EnumB->hasNameForLinkage() ||
9990 !Context.hasSameType(EnumA->getIntegerType(),
9991 EnumB->getIntegerType()))
9992 return false;
9993 // Allow this only if the value is the same for both enumerators.
9994 return llvm::APSInt::isSameValue(EA->getInitVal(), EB->getInitVal());
9995 }
9996 }
9997
9998 // Nothing else is sufficiently similar.
9999 return false;
10000 }
10001
diagnoseEquivalentInternalLinkageDeclarations(SourceLocation Loc,const NamedDecl * D,ArrayRef<const NamedDecl * > Equiv)10002 void Sema::diagnoseEquivalentInternalLinkageDeclarations(
10003 SourceLocation Loc, const NamedDecl *D, ArrayRef<const NamedDecl *> Equiv) {
10004 assert(D && "Unknown declaration");
10005 Diag(Loc, diag::ext_equivalent_internal_linkage_decl_in_modules) << D;
10006
10007 Module *M = getOwningModule(D);
10008 Diag(D->getLocation(), diag::note_equivalent_internal_linkage_decl)
10009 << !M << (M ? M->getFullModuleName() : "");
10010
10011 for (auto *E : Equiv) {
10012 Module *M = getOwningModule(E);
10013 Diag(E->getLocation(), diag::note_equivalent_internal_linkage_decl)
10014 << !M << (M ? M->getFullModuleName() : "");
10015 }
10016 }
10017
10018 /// Computes the best viable function (C++ 13.3.3)
10019 /// within an overload candidate set.
10020 ///
10021 /// \param Loc The location of the function name (or operator symbol) for
10022 /// which overload resolution occurs.
10023 ///
10024 /// \param Best If overload resolution was successful or found a deleted
10025 /// function, \p Best points to the candidate function found.
10026 ///
10027 /// \returns The result of overload resolution.
10028 OverloadingResult
BestViableFunction(Sema & S,SourceLocation Loc,iterator & Best)10029 OverloadCandidateSet::BestViableFunction(Sema &S, SourceLocation Loc,
10030 iterator &Best) {
10031 llvm::SmallVector<OverloadCandidate *, 16> Candidates;
10032 std::transform(begin(), end(), std::back_inserter(Candidates),
10033 [](OverloadCandidate &Cand) { return &Cand; });
10034
10035 // [CUDA] HD->H or HD->D calls are technically not allowed by CUDA but
10036 // are accepted by both clang and NVCC. However, during a particular
10037 // compilation mode only one call variant is viable. We need to
10038 // exclude non-viable overload candidates from consideration based
10039 // only on their host/device attributes. Specifically, if one
10040 // candidate call is WrongSide and the other is SameSide, we ignore
10041 // the WrongSide candidate.
10042 // We only need to remove wrong-sided candidates here if
10043 // -fgpu-exclude-wrong-side-overloads is off. When
10044 // -fgpu-exclude-wrong-side-overloads is on, all candidates are compared
10045 // uniformly in isBetterOverloadCandidate.
10046 if (S.getLangOpts().CUDA && !S.getLangOpts().GPUExcludeWrongSideOverloads) {
10047 const FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext);
10048 bool ContainsSameSideCandidate =
10049 llvm::any_of(Candidates, [&](OverloadCandidate *Cand) {
10050 // Check viable function only.
10051 return Cand->Viable && Cand->Function &&
10052 S.IdentifyCUDAPreference(Caller, Cand->Function) ==
10053 Sema::CFP_SameSide;
10054 });
10055 if (ContainsSameSideCandidate) {
10056 auto IsWrongSideCandidate = [&](OverloadCandidate *Cand) {
10057 // Check viable function only to avoid unnecessary data copying/moving.
10058 return Cand->Viable && Cand->Function &&
10059 S.IdentifyCUDAPreference(Caller, Cand->Function) ==
10060 Sema::CFP_WrongSide;
10061 };
10062 llvm::erase_if(Candidates, IsWrongSideCandidate);
10063 }
10064 }
10065
10066 // Find the best viable function.
10067 Best = end();
10068 for (auto *Cand : Candidates) {
10069 Cand->Best = false;
10070 if (Cand->Viable)
10071 if (Best == end() ||
10072 isBetterOverloadCandidate(S, *Cand, *Best, Loc, Kind))
10073 Best = Cand;
10074 }
10075
10076 // If we didn't find any viable functions, abort.
10077 if (Best == end())
10078 return OR_No_Viable_Function;
10079
10080 llvm::SmallVector<const NamedDecl *, 4> EquivalentCands;
10081
10082 llvm::SmallVector<OverloadCandidate*, 4> PendingBest;
10083 PendingBest.push_back(&*Best);
10084 Best->Best = true;
10085
10086 // Make sure that this function is better than every other viable
10087 // function. If not, we have an ambiguity.
10088 while (!PendingBest.empty()) {
10089 auto *Curr = PendingBest.pop_back_val();
10090 for (auto *Cand : Candidates) {
10091 if (Cand->Viable && !Cand->Best &&
10092 !isBetterOverloadCandidate(S, *Curr, *Cand, Loc, Kind)) {
10093 PendingBest.push_back(Cand);
10094 Cand->Best = true;
10095
10096 if (S.isEquivalentInternalLinkageDeclaration(Cand->Function,
10097 Curr->Function))
10098 EquivalentCands.push_back(Cand->Function);
10099 else
10100 Best = end();
10101 }
10102 }
10103 }
10104
10105 // If we found more than one best candidate, this is ambiguous.
10106 if (Best == end())
10107 return OR_Ambiguous;
10108
10109 // Best is the best viable function.
10110 if (Best->Function && Best->Function->isDeleted())
10111 return OR_Deleted;
10112
10113 if (!EquivalentCands.empty())
10114 S.diagnoseEquivalentInternalLinkageDeclarations(Loc, Best->Function,
10115 EquivalentCands);
10116
10117 return OR_Success;
10118 }
10119
10120 namespace {
10121
10122 enum OverloadCandidateKind {
10123 oc_function,
10124 oc_method,
10125 oc_reversed_binary_operator,
10126 oc_constructor,
10127 oc_implicit_default_constructor,
10128 oc_implicit_copy_constructor,
10129 oc_implicit_move_constructor,
10130 oc_implicit_copy_assignment,
10131 oc_implicit_move_assignment,
10132 oc_implicit_equality_comparison,
10133 oc_inherited_constructor
10134 };
10135
10136 enum OverloadCandidateSelect {
10137 ocs_non_template,
10138 ocs_template,
10139 ocs_described_template,
10140 };
10141
10142 static std::pair<OverloadCandidateKind, OverloadCandidateSelect>
ClassifyOverloadCandidate(Sema & S,NamedDecl * Found,FunctionDecl * Fn,OverloadCandidateRewriteKind CRK,std::string & Description)10143 ClassifyOverloadCandidate(Sema &S, NamedDecl *Found, FunctionDecl *Fn,
10144 OverloadCandidateRewriteKind CRK,
10145 std::string &Description) {
10146
10147 bool isTemplate = Fn->isTemplateDecl() || Found->isTemplateDecl();
10148 if (FunctionTemplateDecl *FunTmpl = Fn->getPrimaryTemplate()) {
10149 isTemplate = true;
10150 Description = S.getTemplateArgumentBindingsText(
10151 FunTmpl->getTemplateParameters(), *Fn->getTemplateSpecializationArgs());
10152 }
10153
10154 OverloadCandidateSelect Select = [&]() {
10155 if (!Description.empty())
10156 return ocs_described_template;
10157 return isTemplate ? ocs_template : ocs_non_template;
10158 }();
10159
10160 OverloadCandidateKind Kind = [&]() {
10161 if (Fn->isImplicit() && Fn->getOverloadedOperator() == OO_EqualEqual)
10162 return oc_implicit_equality_comparison;
10163
10164 if (CRK & CRK_Reversed)
10165 return oc_reversed_binary_operator;
10166
10167 if (CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(Fn)) {
10168 if (!Ctor->isImplicit()) {
10169 if (isa<ConstructorUsingShadowDecl>(Found))
10170 return oc_inherited_constructor;
10171 else
10172 return oc_constructor;
10173 }
10174
10175 if (Ctor->isDefaultConstructor())
10176 return oc_implicit_default_constructor;
10177
10178 if (Ctor->isMoveConstructor())
10179 return oc_implicit_move_constructor;
10180
10181 assert(Ctor->isCopyConstructor() &&
10182 "unexpected sort of implicit constructor");
10183 return oc_implicit_copy_constructor;
10184 }
10185
10186 if (CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Fn)) {
10187 // This actually gets spelled 'candidate function' for now, but
10188 // it doesn't hurt to split it out.
10189 if (!Meth->isImplicit())
10190 return oc_method;
10191
10192 if (Meth->isMoveAssignmentOperator())
10193 return oc_implicit_move_assignment;
10194
10195 if (Meth->isCopyAssignmentOperator())
10196 return oc_implicit_copy_assignment;
10197
10198 assert(isa<CXXConversionDecl>(Meth) && "expected conversion");
10199 return oc_method;
10200 }
10201
10202 return oc_function;
10203 }();
10204
10205 return std::make_pair(Kind, Select);
10206 }
10207
MaybeEmitInheritedConstructorNote(Sema & S,Decl * FoundDecl)10208 void MaybeEmitInheritedConstructorNote(Sema &S, Decl *FoundDecl) {
10209 // FIXME: It'd be nice to only emit a note once per using-decl per overload
10210 // set.
10211 if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(FoundDecl))
10212 S.Diag(FoundDecl->getLocation(),
10213 diag::note_ovl_candidate_inherited_constructor)
10214 << Shadow->getNominatedBaseClass();
10215 }
10216
10217 } // end anonymous namespace
10218
isFunctionAlwaysEnabled(const ASTContext & Ctx,const FunctionDecl * FD)10219 static bool isFunctionAlwaysEnabled(const ASTContext &Ctx,
10220 const FunctionDecl *FD) {
10221 for (auto *EnableIf : FD->specific_attrs<EnableIfAttr>()) {
10222 bool AlwaysTrue;
10223 if (EnableIf->getCond()->isValueDependent() ||
10224 !EnableIf->getCond()->EvaluateAsBooleanCondition(AlwaysTrue, Ctx))
10225 return false;
10226 if (!AlwaysTrue)
10227 return false;
10228 }
10229 return true;
10230 }
10231
10232 /// Returns true if we can take the address of the function.
10233 ///
10234 /// \param Complain - If true, we'll emit a diagnostic
10235 /// \param InOverloadResolution - For the purposes of emitting a diagnostic, are
10236 /// we in overload resolution?
10237 /// \param Loc - The location of the statement we're complaining about. Ignored
10238 /// if we're not complaining, or if we're in overload resolution.
checkAddressOfFunctionIsAvailable(Sema & S,const FunctionDecl * FD,bool Complain,bool InOverloadResolution,SourceLocation Loc)10239 static bool checkAddressOfFunctionIsAvailable(Sema &S, const FunctionDecl *FD,
10240 bool Complain,
10241 bool InOverloadResolution,
10242 SourceLocation Loc) {
10243 if (!isFunctionAlwaysEnabled(S.Context, FD)) {
10244 if (Complain) {
10245 if (InOverloadResolution)
10246 S.Diag(FD->getBeginLoc(),
10247 diag::note_addrof_ovl_candidate_disabled_by_enable_if_attr);
10248 else
10249 S.Diag(Loc, diag::err_addrof_function_disabled_by_enable_if_attr) << FD;
10250 }
10251 return false;
10252 }
10253
10254 if (FD->getTrailingRequiresClause()) {
10255 ConstraintSatisfaction Satisfaction;
10256 if (S.CheckFunctionConstraints(FD, Satisfaction, Loc))
10257 return false;
10258 if (!Satisfaction.IsSatisfied) {
10259 if (Complain) {
10260 if (InOverloadResolution)
10261 S.Diag(FD->getBeginLoc(),
10262 diag::note_ovl_candidate_unsatisfied_constraints);
10263 else
10264 S.Diag(Loc, diag::err_addrof_function_constraints_not_satisfied)
10265 << FD;
10266 S.DiagnoseUnsatisfiedConstraint(Satisfaction);
10267 }
10268 return false;
10269 }
10270 }
10271
10272 auto I = llvm::find_if(FD->parameters(), [](const ParmVarDecl *P) {
10273 return P->hasAttr<PassObjectSizeAttr>();
10274 });
10275 if (I == FD->param_end())
10276 return true;
10277
10278 if (Complain) {
10279 // Add one to ParamNo because it's user-facing
10280 unsigned ParamNo = std::distance(FD->param_begin(), I) + 1;
10281 if (InOverloadResolution)
10282 S.Diag(FD->getLocation(),
10283 diag::note_ovl_candidate_has_pass_object_size_params)
10284 << ParamNo;
10285 else
10286 S.Diag(Loc, diag::err_address_of_function_with_pass_object_size_params)
10287 << FD << ParamNo;
10288 }
10289 return false;
10290 }
10291
checkAddressOfCandidateIsAvailable(Sema & S,const FunctionDecl * FD)10292 static bool checkAddressOfCandidateIsAvailable(Sema &S,
10293 const FunctionDecl *FD) {
10294 return checkAddressOfFunctionIsAvailable(S, FD, /*Complain=*/true,
10295 /*InOverloadResolution=*/true,
10296 /*Loc=*/SourceLocation());
10297 }
10298
checkAddressOfFunctionIsAvailable(const FunctionDecl * Function,bool Complain,SourceLocation Loc)10299 bool Sema::checkAddressOfFunctionIsAvailable(const FunctionDecl *Function,
10300 bool Complain,
10301 SourceLocation Loc) {
10302 return ::checkAddressOfFunctionIsAvailable(*this, Function, Complain,
10303 /*InOverloadResolution=*/false,
10304 Loc);
10305 }
10306
10307 // Don't print candidates other than the one that matches the calling
10308 // convention of the call operator, since that is guaranteed to exist.
shouldSkipNotingLambdaConversionDecl(FunctionDecl * Fn)10309 static bool shouldSkipNotingLambdaConversionDecl(FunctionDecl *Fn) {
10310 const auto *ConvD = dyn_cast<CXXConversionDecl>(Fn);
10311
10312 if (!ConvD)
10313 return false;
10314 const auto *RD = cast<CXXRecordDecl>(Fn->getParent());
10315 if (!RD->isLambda())
10316 return false;
10317
10318 CXXMethodDecl *CallOp = RD->getLambdaCallOperator();
10319 CallingConv CallOpCC =
10320 CallOp->getType()->castAs<FunctionType>()->getCallConv();
10321 QualType ConvRTy = ConvD->getType()->castAs<FunctionType>()->getReturnType();
10322 CallingConv ConvToCC =
10323 ConvRTy->getPointeeType()->castAs<FunctionType>()->getCallConv();
10324
10325 return ConvToCC != CallOpCC;
10326 }
10327
10328 // Notes the location of an overload candidate.
NoteOverloadCandidate(NamedDecl * Found,FunctionDecl * Fn,OverloadCandidateRewriteKind RewriteKind,QualType DestType,bool TakingAddress)10329 void Sema::NoteOverloadCandidate(NamedDecl *Found, FunctionDecl *Fn,
10330 OverloadCandidateRewriteKind RewriteKind,
10331 QualType DestType, bool TakingAddress) {
10332 if (TakingAddress && !checkAddressOfCandidateIsAvailable(*this, Fn))
10333 return;
10334 if (Fn->isMultiVersion() && Fn->hasAttr<TargetAttr>() &&
10335 !Fn->getAttr<TargetAttr>()->isDefaultVersion())
10336 return;
10337 if (shouldSkipNotingLambdaConversionDecl(Fn))
10338 return;
10339
10340 std::string FnDesc;
10341 std::pair<OverloadCandidateKind, OverloadCandidateSelect> KSPair =
10342 ClassifyOverloadCandidate(*this, Found, Fn, RewriteKind, FnDesc);
10343 PartialDiagnostic PD = PDiag(diag::note_ovl_candidate)
10344 << (unsigned)KSPair.first << (unsigned)KSPair.second
10345 << Fn << FnDesc;
10346
10347 HandleFunctionTypeMismatch(PD, Fn->getType(), DestType);
10348 Diag(Fn->getLocation(), PD);
10349 MaybeEmitInheritedConstructorNote(*this, Found);
10350 }
10351
10352 static void
MaybeDiagnoseAmbiguousConstraints(Sema & S,ArrayRef<OverloadCandidate> Cands)10353 MaybeDiagnoseAmbiguousConstraints(Sema &S, ArrayRef<OverloadCandidate> Cands) {
10354 // Perhaps the ambiguity was caused by two atomic constraints that are
10355 // 'identical' but not equivalent:
10356 //
10357 // void foo() requires (sizeof(T) > 4) { } // #1
10358 // void foo() requires (sizeof(T) > 4) && T::value { } // #2
10359 //
10360 // The 'sizeof(T) > 4' constraints are seemingly equivalent and should cause
10361 // #2 to subsume #1, but these constraint are not considered equivalent
10362 // according to the subsumption rules because they are not the same
10363 // source-level construct. This behavior is quite confusing and we should try
10364 // to help the user figure out what happened.
10365
10366 SmallVector<const Expr *, 3> FirstAC, SecondAC;
10367 FunctionDecl *FirstCand = nullptr, *SecondCand = nullptr;
10368 for (auto I = Cands.begin(), E = Cands.end(); I != E; ++I) {
10369 if (!I->Function)
10370 continue;
10371 SmallVector<const Expr *, 3> AC;
10372 if (auto *Template = I->Function->getPrimaryTemplate())
10373 Template->getAssociatedConstraints(AC);
10374 else
10375 I->Function->getAssociatedConstraints(AC);
10376 if (AC.empty())
10377 continue;
10378 if (FirstCand == nullptr) {
10379 FirstCand = I->Function;
10380 FirstAC = AC;
10381 } else if (SecondCand == nullptr) {
10382 SecondCand = I->Function;
10383 SecondAC = AC;
10384 } else {
10385 // We have more than one pair of constrained functions - this check is
10386 // expensive and we'd rather not try to diagnose it.
10387 return;
10388 }
10389 }
10390 if (!SecondCand)
10391 return;
10392 // The diagnostic can only happen if there are associated constraints on
10393 // both sides (there needs to be some identical atomic constraint).
10394 if (S.MaybeEmitAmbiguousAtomicConstraintsDiagnostic(FirstCand, FirstAC,
10395 SecondCand, SecondAC))
10396 // Just show the user one diagnostic, they'll probably figure it out
10397 // from here.
10398 return;
10399 }
10400
10401 // Notes the location of all overload candidates designated through
10402 // OverloadedExpr
NoteAllOverloadCandidates(Expr * OverloadedExpr,QualType DestType,bool TakingAddress)10403 void Sema::NoteAllOverloadCandidates(Expr *OverloadedExpr, QualType DestType,
10404 bool TakingAddress) {
10405 assert(OverloadedExpr->getType() == Context.OverloadTy);
10406
10407 OverloadExpr::FindResult Ovl = OverloadExpr::find(OverloadedExpr);
10408 OverloadExpr *OvlExpr = Ovl.Expression;
10409
10410 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
10411 IEnd = OvlExpr->decls_end();
10412 I != IEnd; ++I) {
10413 if (FunctionTemplateDecl *FunTmpl =
10414 dyn_cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl()) ) {
10415 NoteOverloadCandidate(*I, FunTmpl->getTemplatedDecl(), CRK_None, DestType,
10416 TakingAddress);
10417 } else if (FunctionDecl *Fun
10418 = dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()) ) {
10419 NoteOverloadCandidate(*I, Fun, CRK_None, DestType, TakingAddress);
10420 }
10421 }
10422 }
10423
10424 /// Diagnoses an ambiguous conversion. The partial diagnostic is the
10425 /// "lead" diagnostic; it will be given two arguments, the source and
10426 /// target types of the conversion.
DiagnoseAmbiguousConversion(Sema & S,SourceLocation CaretLoc,const PartialDiagnostic & PDiag) const10427 void ImplicitConversionSequence::DiagnoseAmbiguousConversion(
10428 Sema &S,
10429 SourceLocation CaretLoc,
10430 const PartialDiagnostic &PDiag) const {
10431 S.Diag(CaretLoc, PDiag)
10432 << Ambiguous.getFromType() << Ambiguous.getToType();
10433 unsigned CandsShown = 0;
10434 AmbiguousConversionSequence::const_iterator I, E;
10435 for (I = Ambiguous.begin(), E = Ambiguous.end(); I != E; ++I) {
10436 if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow())
10437 break;
10438 ++CandsShown;
10439 S.NoteOverloadCandidate(I->first, I->second);
10440 }
10441 S.Diags.overloadCandidatesShown(CandsShown);
10442 if (I != E)
10443 S.Diag(SourceLocation(), diag::note_ovl_too_many_candidates) << int(E - I);
10444 }
10445
DiagnoseBadConversion(Sema & S,OverloadCandidate * Cand,unsigned I,bool TakingCandidateAddress)10446 static void DiagnoseBadConversion(Sema &S, OverloadCandidate *Cand,
10447 unsigned I, bool TakingCandidateAddress) {
10448 const ImplicitConversionSequence &Conv = Cand->Conversions[I];
10449 assert(Conv.isBad());
10450 assert(Cand->Function && "for now, candidate must be a function");
10451 FunctionDecl *Fn = Cand->Function;
10452
10453 // There's a conversion slot for the object argument if this is a
10454 // non-constructor method. Note that 'I' corresponds the
10455 // conversion-slot index.
10456 bool isObjectArgument = false;
10457 if (isa<CXXMethodDecl>(Fn) && !isa<CXXConstructorDecl>(Fn)) {
10458 if (I == 0)
10459 isObjectArgument = true;
10460 else
10461 I--;
10462 }
10463
10464 std::string FnDesc;
10465 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
10466 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn, Cand->getRewriteKind(),
10467 FnDesc);
10468
10469 Expr *FromExpr = Conv.Bad.FromExpr;
10470 QualType FromTy = Conv.Bad.getFromType();
10471 QualType ToTy = Conv.Bad.getToType();
10472
10473 if (FromTy == S.Context.OverloadTy) {
10474 assert(FromExpr && "overload set argument came from implicit argument?");
10475 Expr *E = FromExpr->IgnoreParens();
10476 if (isa<UnaryOperator>(E))
10477 E = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
10478 DeclarationName Name = cast<OverloadExpr>(E)->getName();
10479
10480 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_overload)
10481 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10482 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << ToTy
10483 << Name << I + 1;
10484 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10485 return;
10486 }
10487
10488 // Do some hand-waving analysis to see if the non-viability is due
10489 // to a qualifier mismatch.
10490 CanQualType CFromTy = S.Context.getCanonicalType(FromTy);
10491 CanQualType CToTy = S.Context.getCanonicalType(ToTy);
10492 if (CanQual<ReferenceType> RT = CToTy->getAs<ReferenceType>())
10493 CToTy = RT->getPointeeType();
10494 else {
10495 // TODO: detect and diagnose the full richness of const mismatches.
10496 if (CanQual<PointerType> FromPT = CFromTy->getAs<PointerType>())
10497 if (CanQual<PointerType> ToPT = CToTy->getAs<PointerType>()) {
10498 CFromTy = FromPT->getPointeeType();
10499 CToTy = ToPT->getPointeeType();
10500 }
10501 }
10502
10503 if (CToTy.getUnqualifiedType() == CFromTy.getUnqualifiedType() &&
10504 !CToTy.isAtLeastAsQualifiedAs(CFromTy)) {
10505 Qualifiers FromQs = CFromTy.getQualifiers();
10506 Qualifiers ToQs = CToTy.getQualifiers();
10507
10508 if (FromQs.getAddressSpace() != ToQs.getAddressSpace()) {
10509 if (isObjectArgument)
10510 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace_this)
10511 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10512 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10513 << FromQs.getAddressSpace() << ToQs.getAddressSpace();
10514 else
10515 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_addrspace)
10516 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10517 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10518 << FromQs.getAddressSpace() << ToQs.getAddressSpace()
10519 << ToTy->isReferenceType() << I + 1;
10520 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10521 return;
10522 }
10523
10524 if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
10525 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_ownership)
10526 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10527 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10528 << FromQs.getObjCLifetime() << ToQs.getObjCLifetime()
10529 << (unsigned)isObjectArgument << I + 1;
10530 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10531 return;
10532 }
10533
10534 if (FromQs.getObjCGCAttr() != ToQs.getObjCGCAttr()) {
10535 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_gc)
10536 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10537 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10538 << FromQs.getObjCGCAttr() << ToQs.getObjCGCAttr()
10539 << (unsigned)isObjectArgument << I + 1;
10540 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10541 return;
10542 }
10543
10544 if (FromQs.hasUnaligned() != ToQs.hasUnaligned()) {
10545 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_unaligned)
10546 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10547 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10548 << FromQs.hasUnaligned() << I + 1;
10549 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10550 return;
10551 }
10552
10553 unsigned CVR = FromQs.getCVRQualifiers() & ~ToQs.getCVRQualifiers();
10554 assert(CVR && "expected qualifiers mismatch");
10555
10556 if (isObjectArgument) {
10557 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr_this)
10558 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10559 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10560 << (CVR - 1);
10561 } else {
10562 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_cvr)
10563 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10564 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10565 << (CVR - 1) << I + 1;
10566 }
10567 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10568 return;
10569 }
10570
10571 if (Conv.Bad.Kind == BadConversionSequence::lvalue_ref_to_rvalue ||
10572 Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue) {
10573 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_value_category)
10574 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10575 << (unsigned)isObjectArgument << I + 1
10576 << (Conv.Bad.Kind == BadConversionSequence::rvalue_ref_to_lvalue)
10577 << (FromExpr ? FromExpr->getSourceRange() : SourceRange());
10578 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10579 return;
10580 }
10581
10582 // Special diagnostic for failure to convert an initializer list, since
10583 // telling the user that it has type void is not useful.
10584 if (FromExpr && isa<InitListExpr>(FromExpr)) {
10585 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_list_argument)
10586 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10587 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10588 << ToTy << (unsigned)isObjectArgument << I + 1
10589 << (Conv.Bad.Kind == BadConversionSequence::too_few_initializers ? 1
10590 : Conv.Bad.Kind == BadConversionSequence::too_many_initializers
10591 ? 2
10592 : 0);
10593 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10594 return;
10595 }
10596
10597 // Diagnose references or pointers to incomplete types differently,
10598 // since it's far from impossible that the incompleteness triggered
10599 // the failure.
10600 QualType TempFromTy = FromTy.getNonReferenceType();
10601 if (const PointerType *PTy = TempFromTy->getAs<PointerType>())
10602 TempFromTy = PTy->getPointeeType();
10603 if (TempFromTy->isIncompleteType()) {
10604 // Emit the generic diagnostic and, optionally, add the hints to it.
10605 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_conv_incomplete)
10606 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10607 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10608 << ToTy << (unsigned)isObjectArgument << I + 1
10609 << (unsigned)(Cand->Fix.Kind);
10610
10611 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10612 return;
10613 }
10614
10615 // Diagnose base -> derived pointer conversions.
10616 unsigned BaseToDerivedConversion = 0;
10617 if (const PointerType *FromPtrTy = FromTy->getAs<PointerType>()) {
10618 if (const PointerType *ToPtrTy = ToTy->getAs<PointerType>()) {
10619 if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
10620 FromPtrTy->getPointeeType()) &&
10621 !FromPtrTy->getPointeeType()->isIncompleteType() &&
10622 !ToPtrTy->getPointeeType()->isIncompleteType() &&
10623 S.IsDerivedFrom(SourceLocation(), ToPtrTy->getPointeeType(),
10624 FromPtrTy->getPointeeType()))
10625 BaseToDerivedConversion = 1;
10626 }
10627 } else if (const ObjCObjectPointerType *FromPtrTy
10628 = FromTy->getAs<ObjCObjectPointerType>()) {
10629 if (const ObjCObjectPointerType *ToPtrTy
10630 = ToTy->getAs<ObjCObjectPointerType>())
10631 if (const ObjCInterfaceDecl *FromIface = FromPtrTy->getInterfaceDecl())
10632 if (const ObjCInterfaceDecl *ToIface = ToPtrTy->getInterfaceDecl())
10633 if (ToPtrTy->getPointeeType().isAtLeastAsQualifiedAs(
10634 FromPtrTy->getPointeeType()) &&
10635 FromIface->isSuperClassOf(ToIface))
10636 BaseToDerivedConversion = 2;
10637 } else if (const ReferenceType *ToRefTy = ToTy->getAs<ReferenceType>()) {
10638 if (ToRefTy->getPointeeType().isAtLeastAsQualifiedAs(FromTy) &&
10639 !FromTy->isIncompleteType() &&
10640 !ToRefTy->getPointeeType()->isIncompleteType() &&
10641 S.IsDerivedFrom(SourceLocation(), ToRefTy->getPointeeType(), FromTy)) {
10642 BaseToDerivedConversion = 3;
10643 }
10644 }
10645
10646 if (BaseToDerivedConversion) {
10647 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_base_to_derived_conv)
10648 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10649 << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10650 << (BaseToDerivedConversion - 1) << FromTy << ToTy << I + 1;
10651 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10652 return;
10653 }
10654
10655 if (isa<ObjCObjectPointerType>(CFromTy) &&
10656 isa<PointerType>(CToTy)) {
10657 Qualifiers FromQs = CFromTy.getQualifiers();
10658 Qualifiers ToQs = CToTy.getQualifiers();
10659 if (FromQs.getObjCLifetime() != ToQs.getObjCLifetime()) {
10660 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_bad_arc_conv)
10661 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10662 << FnDesc << (FromExpr ? FromExpr->getSourceRange() : SourceRange())
10663 << FromTy << ToTy << (unsigned)isObjectArgument << I + 1;
10664 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10665 return;
10666 }
10667 }
10668
10669 if (TakingCandidateAddress &&
10670 !checkAddressOfCandidateIsAvailable(S, Cand->Function))
10671 return;
10672
10673 // Emit the generic diagnostic and, optionally, add the hints to it.
10674 PartialDiagnostic FDiag = S.PDiag(diag::note_ovl_candidate_bad_conv);
10675 FDiag << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
10676 << (FromExpr ? FromExpr->getSourceRange() : SourceRange()) << FromTy
10677 << ToTy << (unsigned)isObjectArgument << I + 1
10678 << (unsigned)(Cand->Fix.Kind);
10679
10680 // If we can fix the conversion, suggest the FixIts.
10681 for (std::vector<FixItHint>::iterator HI = Cand->Fix.Hints.begin(),
10682 HE = Cand->Fix.Hints.end(); HI != HE; ++HI)
10683 FDiag << *HI;
10684 S.Diag(Fn->getLocation(), FDiag);
10685
10686 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
10687 }
10688
10689 /// Additional arity mismatch diagnosis specific to a function overload
10690 /// candidates. This is not covered by the more general DiagnoseArityMismatch()
10691 /// over a candidate in any candidate set.
CheckArityMismatch(Sema & S,OverloadCandidate * Cand,unsigned NumArgs)10692 static bool CheckArityMismatch(Sema &S, OverloadCandidate *Cand,
10693 unsigned NumArgs) {
10694 FunctionDecl *Fn = Cand->Function;
10695 unsigned MinParams = Fn->getMinRequiredArguments();
10696
10697 // With invalid overloaded operators, it's possible that we think we
10698 // have an arity mismatch when in fact it looks like we have the
10699 // right number of arguments, because only overloaded operators have
10700 // the weird behavior of overloading member and non-member functions.
10701 // Just don't report anything.
10702 if (Fn->isInvalidDecl() &&
10703 Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
10704 return true;
10705
10706 if (NumArgs < MinParams) {
10707 assert((Cand->FailureKind == ovl_fail_too_few_arguments) ||
10708 (Cand->FailureKind == ovl_fail_bad_deduction &&
10709 Cand->DeductionFailure.Result == Sema::TDK_TooFewArguments));
10710 } else {
10711 assert((Cand->FailureKind == ovl_fail_too_many_arguments) ||
10712 (Cand->FailureKind == ovl_fail_bad_deduction &&
10713 Cand->DeductionFailure.Result == Sema::TDK_TooManyArguments));
10714 }
10715
10716 return false;
10717 }
10718
10719 /// General arity mismatch diagnosis over a candidate in a candidate set.
DiagnoseArityMismatch(Sema & S,NamedDecl * Found,Decl * D,unsigned NumFormalArgs)10720 static void DiagnoseArityMismatch(Sema &S, NamedDecl *Found, Decl *D,
10721 unsigned NumFormalArgs) {
10722 assert(isa<FunctionDecl>(D) &&
10723 "The templated declaration should at least be a function"
10724 " when diagnosing bad template argument deduction due to too many"
10725 " or too few arguments");
10726
10727 FunctionDecl *Fn = cast<FunctionDecl>(D);
10728
10729 // TODO: treat calls to a missing default constructor as a special case
10730 const auto *FnTy = Fn->getType()->castAs<FunctionProtoType>();
10731 unsigned MinParams = Fn->getMinRequiredArguments();
10732
10733 // at least / at most / exactly
10734 unsigned mode, modeCount;
10735 if (NumFormalArgs < MinParams) {
10736 if (MinParams != FnTy->getNumParams() || FnTy->isVariadic() ||
10737 FnTy->isTemplateVariadic())
10738 mode = 0; // "at least"
10739 else
10740 mode = 2; // "exactly"
10741 modeCount = MinParams;
10742 } else {
10743 if (MinParams != FnTy->getNumParams())
10744 mode = 1; // "at most"
10745 else
10746 mode = 2; // "exactly"
10747 modeCount = FnTy->getNumParams();
10748 }
10749
10750 std::string Description;
10751 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
10752 ClassifyOverloadCandidate(S, Found, Fn, CRK_None, Description);
10753
10754 if (modeCount == 1 && Fn->getParamDecl(0)->getDeclName())
10755 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity_one)
10756 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10757 << Description << mode << Fn->getParamDecl(0) << NumFormalArgs;
10758 else
10759 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_arity)
10760 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second
10761 << Description << mode << modeCount << NumFormalArgs;
10762
10763 MaybeEmitInheritedConstructorNote(S, Found);
10764 }
10765
10766 /// Arity mismatch diagnosis specific to a function overload candidate.
DiagnoseArityMismatch(Sema & S,OverloadCandidate * Cand,unsigned NumFormalArgs)10767 static void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
10768 unsigned NumFormalArgs) {
10769 if (!CheckArityMismatch(S, Cand, NumFormalArgs))
10770 DiagnoseArityMismatch(S, Cand->FoundDecl, Cand->Function, NumFormalArgs);
10771 }
10772
getDescribedTemplate(Decl * Templated)10773 static TemplateDecl *getDescribedTemplate(Decl *Templated) {
10774 if (TemplateDecl *TD = Templated->getDescribedTemplate())
10775 return TD;
10776 llvm_unreachable("Unsupported: Getting the described template declaration"
10777 " for bad deduction diagnosis");
10778 }
10779
10780 /// Diagnose a failed template-argument deduction.
DiagnoseBadDeduction(Sema & S,NamedDecl * Found,Decl * Templated,DeductionFailureInfo & DeductionFailure,unsigned NumArgs,bool TakingCandidateAddress)10781 static void DiagnoseBadDeduction(Sema &S, NamedDecl *Found, Decl *Templated,
10782 DeductionFailureInfo &DeductionFailure,
10783 unsigned NumArgs,
10784 bool TakingCandidateAddress) {
10785 TemplateParameter Param = DeductionFailure.getTemplateParameter();
10786 NamedDecl *ParamD;
10787 (ParamD = Param.dyn_cast<TemplateTypeParmDecl*>()) ||
10788 (ParamD = Param.dyn_cast<NonTypeTemplateParmDecl*>()) ||
10789 (ParamD = Param.dyn_cast<TemplateTemplateParmDecl*>());
10790 switch (DeductionFailure.Result) {
10791 case Sema::TDK_Success:
10792 llvm_unreachable("TDK_success while diagnosing bad deduction");
10793
10794 case Sema::TDK_Incomplete: {
10795 assert(ParamD && "no parameter found for incomplete deduction result");
10796 S.Diag(Templated->getLocation(),
10797 diag::note_ovl_candidate_incomplete_deduction)
10798 << ParamD->getDeclName();
10799 MaybeEmitInheritedConstructorNote(S, Found);
10800 return;
10801 }
10802
10803 case Sema::TDK_IncompletePack: {
10804 assert(ParamD && "no parameter found for incomplete deduction result");
10805 S.Diag(Templated->getLocation(),
10806 diag::note_ovl_candidate_incomplete_deduction_pack)
10807 << ParamD->getDeclName()
10808 << (DeductionFailure.getFirstArg()->pack_size() + 1)
10809 << *DeductionFailure.getFirstArg();
10810 MaybeEmitInheritedConstructorNote(S, Found);
10811 return;
10812 }
10813
10814 case Sema::TDK_Underqualified: {
10815 assert(ParamD && "no parameter found for bad qualifiers deduction result");
10816 TemplateTypeParmDecl *TParam = cast<TemplateTypeParmDecl>(ParamD);
10817
10818 QualType Param = DeductionFailure.getFirstArg()->getAsType();
10819
10820 // Param will have been canonicalized, but it should just be a
10821 // qualified version of ParamD, so move the qualifiers to that.
10822 QualifierCollector Qs;
10823 Qs.strip(Param);
10824 QualType NonCanonParam = Qs.apply(S.Context, TParam->getTypeForDecl());
10825 assert(S.Context.hasSameType(Param, NonCanonParam));
10826
10827 // Arg has also been canonicalized, but there's nothing we can do
10828 // about that. It also doesn't matter as much, because it won't
10829 // have any template parameters in it (because deduction isn't
10830 // done on dependent types).
10831 QualType Arg = DeductionFailure.getSecondArg()->getAsType();
10832
10833 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_underqualified)
10834 << ParamD->getDeclName() << Arg << NonCanonParam;
10835 MaybeEmitInheritedConstructorNote(S, Found);
10836 return;
10837 }
10838
10839 case Sema::TDK_Inconsistent: {
10840 assert(ParamD && "no parameter found for inconsistent deduction result");
10841 int which = 0;
10842 if (isa<TemplateTypeParmDecl>(ParamD))
10843 which = 0;
10844 else if (isa<NonTypeTemplateParmDecl>(ParamD)) {
10845 // Deduction might have failed because we deduced arguments of two
10846 // different types for a non-type template parameter.
10847 // FIXME: Use a different TDK value for this.
10848 QualType T1 =
10849 DeductionFailure.getFirstArg()->getNonTypeTemplateArgumentType();
10850 QualType T2 =
10851 DeductionFailure.getSecondArg()->getNonTypeTemplateArgumentType();
10852 if (!T1.isNull() && !T2.isNull() && !S.Context.hasSameType(T1, T2)) {
10853 S.Diag(Templated->getLocation(),
10854 diag::note_ovl_candidate_inconsistent_deduction_types)
10855 << ParamD->getDeclName() << *DeductionFailure.getFirstArg() << T1
10856 << *DeductionFailure.getSecondArg() << T2;
10857 MaybeEmitInheritedConstructorNote(S, Found);
10858 return;
10859 }
10860
10861 which = 1;
10862 } else {
10863 which = 2;
10864 }
10865
10866 // Tweak the diagnostic if the problem is that we deduced packs of
10867 // different arities. We'll print the actual packs anyway in case that
10868 // includes additional useful information.
10869 if (DeductionFailure.getFirstArg()->getKind() == TemplateArgument::Pack &&
10870 DeductionFailure.getSecondArg()->getKind() == TemplateArgument::Pack &&
10871 DeductionFailure.getFirstArg()->pack_size() !=
10872 DeductionFailure.getSecondArg()->pack_size()) {
10873 which = 3;
10874 }
10875
10876 S.Diag(Templated->getLocation(),
10877 diag::note_ovl_candidate_inconsistent_deduction)
10878 << which << ParamD->getDeclName() << *DeductionFailure.getFirstArg()
10879 << *DeductionFailure.getSecondArg();
10880 MaybeEmitInheritedConstructorNote(S, Found);
10881 return;
10882 }
10883
10884 case Sema::TDK_InvalidExplicitArguments:
10885 assert(ParamD && "no parameter found for invalid explicit arguments");
10886 if (ParamD->getDeclName())
10887 S.Diag(Templated->getLocation(),
10888 diag::note_ovl_candidate_explicit_arg_mismatch_named)
10889 << ParamD->getDeclName();
10890 else {
10891 int index = 0;
10892 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ParamD))
10893 index = TTP->getIndex();
10894 else if (NonTypeTemplateParmDecl *NTTP
10895 = dyn_cast<NonTypeTemplateParmDecl>(ParamD))
10896 index = NTTP->getIndex();
10897 else
10898 index = cast<TemplateTemplateParmDecl>(ParamD)->getIndex();
10899 S.Diag(Templated->getLocation(),
10900 diag::note_ovl_candidate_explicit_arg_mismatch_unnamed)
10901 << (index + 1);
10902 }
10903 MaybeEmitInheritedConstructorNote(S, Found);
10904 return;
10905
10906 case Sema::TDK_ConstraintsNotSatisfied: {
10907 // Format the template argument list into the argument string.
10908 SmallString<128> TemplateArgString;
10909 TemplateArgumentList *Args = DeductionFailure.getTemplateArgumentList();
10910 TemplateArgString = " ";
10911 TemplateArgString += S.getTemplateArgumentBindingsText(
10912 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10913 if (TemplateArgString.size() == 1)
10914 TemplateArgString.clear();
10915 S.Diag(Templated->getLocation(),
10916 diag::note_ovl_candidate_unsatisfied_constraints)
10917 << TemplateArgString;
10918
10919 S.DiagnoseUnsatisfiedConstraint(
10920 static_cast<CNSInfo*>(DeductionFailure.Data)->Satisfaction);
10921 return;
10922 }
10923 case Sema::TDK_TooManyArguments:
10924 case Sema::TDK_TooFewArguments:
10925 DiagnoseArityMismatch(S, Found, Templated, NumArgs);
10926 return;
10927
10928 case Sema::TDK_InstantiationDepth:
10929 S.Diag(Templated->getLocation(),
10930 diag::note_ovl_candidate_instantiation_depth);
10931 MaybeEmitInheritedConstructorNote(S, Found);
10932 return;
10933
10934 case Sema::TDK_SubstitutionFailure: {
10935 // Format the template argument list into the argument string.
10936 SmallString<128> TemplateArgString;
10937 if (TemplateArgumentList *Args =
10938 DeductionFailure.getTemplateArgumentList()) {
10939 TemplateArgString = " ";
10940 TemplateArgString += S.getTemplateArgumentBindingsText(
10941 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10942 if (TemplateArgString.size() == 1)
10943 TemplateArgString.clear();
10944 }
10945
10946 // If this candidate was disabled by enable_if, say so.
10947 PartialDiagnosticAt *PDiag = DeductionFailure.getSFINAEDiagnostic();
10948 if (PDiag && PDiag->second.getDiagID() ==
10949 diag::err_typename_nested_not_found_enable_if) {
10950 // FIXME: Use the source range of the condition, and the fully-qualified
10951 // name of the enable_if template. These are both present in PDiag.
10952 S.Diag(PDiag->first, diag::note_ovl_candidate_disabled_by_enable_if)
10953 << "'enable_if'" << TemplateArgString;
10954 return;
10955 }
10956
10957 // We found a specific requirement that disabled the enable_if.
10958 if (PDiag && PDiag->second.getDiagID() ==
10959 diag::err_typename_nested_not_found_requirement) {
10960 S.Diag(Templated->getLocation(),
10961 diag::note_ovl_candidate_disabled_by_requirement)
10962 << PDiag->second.getStringArg(0) << TemplateArgString;
10963 return;
10964 }
10965
10966 // Format the SFINAE diagnostic into the argument string.
10967 // FIXME: Add a general mechanism to include a PartialDiagnostic *'s
10968 // formatted message in another diagnostic.
10969 SmallString<128> SFINAEArgString;
10970 SourceRange R;
10971 if (PDiag) {
10972 SFINAEArgString = ": ";
10973 R = SourceRange(PDiag->first, PDiag->first);
10974 PDiag->second.EmitToString(S.getDiagnostics(), SFINAEArgString);
10975 }
10976
10977 S.Diag(Templated->getLocation(),
10978 diag::note_ovl_candidate_substitution_failure)
10979 << TemplateArgString << SFINAEArgString << R;
10980 MaybeEmitInheritedConstructorNote(S, Found);
10981 return;
10982 }
10983
10984 case Sema::TDK_DeducedMismatch:
10985 case Sema::TDK_DeducedMismatchNested: {
10986 // Format the template argument list into the argument string.
10987 SmallString<128> TemplateArgString;
10988 if (TemplateArgumentList *Args =
10989 DeductionFailure.getTemplateArgumentList()) {
10990 TemplateArgString = " ";
10991 TemplateArgString += S.getTemplateArgumentBindingsText(
10992 getDescribedTemplate(Templated)->getTemplateParameters(), *Args);
10993 if (TemplateArgString.size() == 1)
10994 TemplateArgString.clear();
10995 }
10996
10997 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_deduced_mismatch)
10998 << (*DeductionFailure.getCallArgIndex() + 1)
10999 << *DeductionFailure.getFirstArg() << *DeductionFailure.getSecondArg()
11000 << TemplateArgString
11001 << (DeductionFailure.Result == Sema::TDK_DeducedMismatchNested);
11002 break;
11003 }
11004
11005 case Sema::TDK_NonDeducedMismatch: {
11006 // FIXME: Provide a source location to indicate what we couldn't match.
11007 TemplateArgument FirstTA = *DeductionFailure.getFirstArg();
11008 TemplateArgument SecondTA = *DeductionFailure.getSecondArg();
11009 if (FirstTA.getKind() == TemplateArgument::Template &&
11010 SecondTA.getKind() == TemplateArgument::Template) {
11011 TemplateName FirstTN = FirstTA.getAsTemplate();
11012 TemplateName SecondTN = SecondTA.getAsTemplate();
11013 if (FirstTN.getKind() == TemplateName::Template &&
11014 SecondTN.getKind() == TemplateName::Template) {
11015 if (FirstTN.getAsTemplateDecl()->getName() ==
11016 SecondTN.getAsTemplateDecl()->getName()) {
11017 // FIXME: This fixes a bad diagnostic where both templates are named
11018 // the same. This particular case is a bit difficult since:
11019 // 1) It is passed as a string to the diagnostic printer.
11020 // 2) The diagnostic printer only attempts to find a better
11021 // name for types, not decls.
11022 // Ideally, this should folded into the diagnostic printer.
11023 S.Diag(Templated->getLocation(),
11024 diag::note_ovl_candidate_non_deduced_mismatch_qualified)
11025 << FirstTN.getAsTemplateDecl() << SecondTN.getAsTemplateDecl();
11026 return;
11027 }
11028 }
11029 }
11030
11031 if (TakingCandidateAddress && isa<FunctionDecl>(Templated) &&
11032 !checkAddressOfCandidateIsAvailable(S, cast<FunctionDecl>(Templated)))
11033 return;
11034
11035 // FIXME: For generic lambda parameters, check if the function is a lambda
11036 // call operator, and if so, emit a prettier and more informative
11037 // diagnostic that mentions 'auto' and lambda in addition to
11038 // (or instead of?) the canonical template type parameters.
11039 S.Diag(Templated->getLocation(),
11040 diag::note_ovl_candidate_non_deduced_mismatch)
11041 << FirstTA << SecondTA;
11042 return;
11043 }
11044 // TODO: diagnose these individually, then kill off
11045 // note_ovl_candidate_bad_deduction, which is uselessly vague.
11046 case Sema::TDK_MiscellaneousDeductionFailure:
11047 S.Diag(Templated->getLocation(), diag::note_ovl_candidate_bad_deduction);
11048 MaybeEmitInheritedConstructorNote(S, Found);
11049 return;
11050 case Sema::TDK_CUDATargetMismatch:
11051 S.Diag(Templated->getLocation(),
11052 diag::note_cuda_ovl_candidate_target_mismatch);
11053 return;
11054 }
11055 }
11056
11057 /// Diagnose a failed template-argument deduction, for function calls.
DiagnoseBadDeduction(Sema & S,OverloadCandidate * Cand,unsigned NumArgs,bool TakingCandidateAddress)11058 static void DiagnoseBadDeduction(Sema &S, OverloadCandidate *Cand,
11059 unsigned NumArgs,
11060 bool TakingCandidateAddress) {
11061 unsigned TDK = Cand->DeductionFailure.Result;
11062 if (TDK == Sema::TDK_TooFewArguments || TDK == Sema::TDK_TooManyArguments) {
11063 if (CheckArityMismatch(S, Cand, NumArgs))
11064 return;
11065 }
11066 DiagnoseBadDeduction(S, Cand->FoundDecl, Cand->Function, // pattern
11067 Cand->DeductionFailure, NumArgs, TakingCandidateAddress);
11068 }
11069
11070 /// CUDA: diagnose an invalid call across targets.
DiagnoseBadTarget(Sema & S,OverloadCandidate * Cand)11071 static void DiagnoseBadTarget(Sema &S, OverloadCandidate *Cand) {
11072 FunctionDecl *Caller = cast<FunctionDecl>(S.CurContext);
11073 FunctionDecl *Callee = Cand->Function;
11074
11075 Sema::CUDAFunctionTarget CallerTarget = S.IdentifyCUDATarget(Caller),
11076 CalleeTarget = S.IdentifyCUDATarget(Callee);
11077
11078 std::string FnDesc;
11079 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
11080 ClassifyOverloadCandidate(S, Cand->FoundDecl, Callee,
11081 Cand->getRewriteKind(), FnDesc);
11082
11083 S.Diag(Callee->getLocation(), diag::note_ovl_candidate_bad_target)
11084 << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
11085 << FnDesc /* Ignored */
11086 << CalleeTarget << CallerTarget;
11087
11088 // This could be an implicit constructor for which we could not infer the
11089 // target due to a collsion. Diagnose that case.
11090 CXXMethodDecl *Meth = dyn_cast<CXXMethodDecl>(Callee);
11091 if (Meth != nullptr && Meth->isImplicit()) {
11092 CXXRecordDecl *ParentClass = Meth->getParent();
11093 Sema::CXXSpecialMember CSM;
11094
11095 switch (FnKindPair.first) {
11096 default:
11097 return;
11098 case oc_implicit_default_constructor:
11099 CSM = Sema::CXXDefaultConstructor;
11100 break;
11101 case oc_implicit_copy_constructor:
11102 CSM = Sema::CXXCopyConstructor;
11103 break;
11104 case oc_implicit_move_constructor:
11105 CSM = Sema::CXXMoveConstructor;
11106 break;
11107 case oc_implicit_copy_assignment:
11108 CSM = Sema::CXXCopyAssignment;
11109 break;
11110 case oc_implicit_move_assignment:
11111 CSM = Sema::CXXMoveAssignment;
11112 break;
11113 };
11114
11115 bool ConstRHS = false;
11116 if (Meth->getNumParams()) {
11117 if (const ReferenceType *RT =
11118 Meth->getParamDecl(0)->getType()->getAs<ReferenceType>()) {
11119 ConstRHS = RT->getPointeeType().isConstQualified();
11120 }
11121 }
11122
11123 S.inferCUDATargetForImplicitSpecialMember(ParentClass, CSM, Meth,
11124 /* ConstRHS */ ConstRHS,
11125 /* Diagnose */ true);
11126 }
11127 }
11128
DiagnoseFailedEnableIfAttr(Sema & S,OverloadCandidate * Cand)11129 static void DiagnoseFailedEnableIfAttr(Sema &S, OverloadCandidate *Cand) {
11130 FunctionDecl *Callee = Cand->Function;
11131 EnableIfAttr *Attr = static_cast<EnableIfAttr*>(Cand->DeductionFailure.Data);
11132
11133 S.Diag(Callee->getLocation(),
11134 diag::note_ovl_candidate_disabled_by_function_cond_attr)
11135 << Attr->getCond()->getSourceRange() << Attr->getMessage();
11136 }
11137
DiagnoseFailedExplicitSpec(Sema & S,OverloadCandidate * Cand)11138 static void DiagnoseFailedExplicitSpec(Sema &S, OverloadCandidate *Cand) {
11139 ExplicitSpecifier ES = ExplicitSpecifier::getFromDecl(Cand->Function);
11140 assert(ES.isExplicit() && "not an explicit candidate");
11141
11142 unsigned Kind;
11143 switch (Cand->Function->getDeclKind()) {
11144 case Decl::Kind::CXXConstructor:
11145 Kind = 0;
11146 break;
11147 case Decl::Kind::CXXConversion:
11148 Kind = 1;
11149 break;
11150 case Decl::Kind::CXXDeductionGuide:
11151 Kind = Cand->Function->isImplicit() ? 0 : 2;
11152 break;
11153 default:
11154 llvm_unreachable("invalid Decl");
11155 }
11156
11157 // Note the location of the first (in-class) declaration; a redeclaration
11158 // (particularly an out-of-class definition) will typically lack the
11159 // 'explicit' specifier.
11160 // FIXME: This is probably a good thing to do for all 'candidate' notes.
11161 FunctionDecl *First = Cand->Function->getFirstDecl();
11162 if (FunctionDecl *Pattern = First->getTemplateInstantiationPattern())
11163 First = Pattern->getFirstDecl();
11164
11165 S.Diag(First->getLocation(),
11166 diag::note_ovl_candidate_explicit)
11167 << Kind << (ES.getExpr() ? 1 : 0)
11168 << (ES.getExpr() ? ES.getExpr()->getSourceRange() : SourceRange());
11169 }
11170
11171 /// Generates a 'note' diagnostic for an overload candidate. We've
11172 /// already generated a primary error at the call site.
11173 ///
11174 /// It really does need to be a single diagnostic with its caret
11175 /// pointed at the candidate declaration. Yes, this creates some
11176 /// major challenges of technical writing. Yes, this makes pointing
11177 /// out problems with specific arguments quite awkward. It's still
11178 /// better than generating twenty screens of text for every failed
11179 /// overload.
11180 ///
11181 /// It would be great to be able to express per-candidate problems
11182 /// more richly for those diagnostic clients that cared, but we'd
11183 /// still have to be just as careful with the default diagnostics.
11184 /// \param CtorDestAS Addr space of object being constructed (for ctor
11185 /// candidates only).
NoteFunctionCandidate(Sema & S,OverloadCandidate * Cand,unsigned NumArgs,bool TakingCandidateAddress,LangAS CtorDestAS=LangAS::Default)11186 static void NoteFunctionCandidate(Sema &S, OverloadCandidate *Cand,
11187 unsigned NumArgs,
11188 bool TakingCandidateAddress,
11189 LangAS CtorDestAS = LangAS::Default) {
11190 FunctionDecl *Fn = Cand->Function;
11191 if (shouldSkipNotingLambdaConversionDecl(Fn))
11192 return;
11193
11194 // Note deleted candidates, but only if they're viable.
11195 if (Cand->Viable) {
11196 if (Fn->isDeleted()) {
11197 std::string FnDesc;
11198 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
11199 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
11200 Cand->getRewriteKind(), FnDesc);
11201
11202 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_deleted)
11203 << (unsigned)FnKindPair.first << (unsigned)FnKindPair.second << FnDesc
11204 << (Fn->isDeleted() ? (Fn->isDeletedAsWritten() ? 1 : 2) : 0);
11205 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11206 return;
11207 }
11208
11209 // We don't really have anything else to say about viable candidates.
11210 S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11211 return;
11212 }
11213
11214 switch (Cand->FailureKind) {
11215 case ovl_fail_too_many_arguments:
11216 case ovl_fail_too_few_arguments:
11217 return DiagnoseArityMismatch(S, Cand, NumArgs);
11218
11219 case ovl_fail_bad_deduction:
11220 return DiagnoseBadDeduction(S, Cand, NumArgs,
11221 TakingCandidateAddress);
11222
11223 case ovl_fail_illegal_constructor: {
11224 S.Diag(Fn->getLocation(), diag::note_ovl_candidate_illegal_constructor)
11225 << (Fn->getPrimaryTemplate() ? 1 : 0);
11226 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11227 return;
11228 }
11229
11230 case ovl_fail_object_addrspace_mismatch: {
11231 Qualifiers QualsForPrinting;
11232 QualsForPrinting.setAddressSpace(CtorDestAS);
11233 S.Diag(Fn->getLocation(),
11234 diag::note_ovl_candidate_illegal_constructor_adrspace_mismatch)
11235 << QualsForPrinting;
11236 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11237 return;
11238 }
11239
11240 case ovl_fail_trivial_conversion:
11241 case ovl_fail_bad_final_conversion:
11242 case ovl_fail_final_conversion_not_exact:
11243 return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11244
11245 case ovl_fail_bad_conversion: {
11246 unsigned I = (Cand->IgnoreObjectArgument ? 1 : 0);
11247 for (unsigned N = Cand->Conversions.size(); I != N; ++I)
11248 if (Cand->Conversions[I].isBad())
11249 return DiagnoseBadConversion(S, Cand, I, TakingCandidateAddress);
11250
11251 // FIXME: this currently happens when we're called from SemaInit
11252 // when user-conversion overload fails. Figure out how to handle
11253 // those conditions and diagnose them well.
11254 return S.NoteOverloadCandidate(Cand->FoundDecl, Fn, Cand->getRewriteKind());
11255 }
11256
11257 case ovl_fail_bad_target:
11258 return DiagnoseBadTarget(S, Cand);
11259
11260 case ovl_fail_enable_if:
11261 return DiagnoseFailedEnableIfAttr(S, Cand);
11262
11263 case ovl_fail_explicit:
11264 return DiagnoseFailedExplicitSpec(S, Cand);
11265
11266 case ovl_fail_inhctor_slice:
11267 // It's generally not interesting to note copy/move constructors here.
11268 if (cast<CXXConstructorDecl>(Fn)->isCopyOrMoveConstructor())
11269 return;
11270 S.Diag(Fn->getLocation(),
11271 diag::note_ovl_candidate_inherited_constructor_slice)
11272 << (Fn->getPrimaryTemplate() ? 1 : 0)
11273 << Fn->getParamDecl(0)->getType()->isRValueReferenceType();
11274 MaybeEmitInheritedConstructorNote(S, Cand->FoundDecl);
11275 return;
11276
11277 case ovl_fail_addr_not_available: {
11278 bool Available = checkAddressOfCandidateIsAvailable(S, Cand->Function);
11279 (void)Available;
11280 assert(!Available);
11281 break;
11282 }
11283 case ovl_non_default_multiversion_function:
11284 // Do nothing, these should simply be ignored.
11285 break;
11286
11287 case ovl_fail_constraints_not_satisfied: {
11288 std::string FnDesc;
11289 std::pair<OverloadCandidateKind, OverloadCandidateSelect> FnKindPair =
11290 ClassifyOverloadCandidate(S, Cand->FoundDecl, Fn,
11291 Cand->getRewriteKind(), FnDesc);
11292
11293 S.Diag(Fn->getLocation(),
11294 diag::note_ovl_candidate_constraints_not_satisfied)
11295 << (unsigned)FnKindPair.first << (unsigned)ocs_non_template
11296 << FnDesc /* Ignored */;
11297 ConstraintSatisfaction Satisfaction;
11298 if (S.CheckFunctionConstraints(Fn, Satisfaction))
11299 break;
11300 S.DiagnoseUnsatisfiedConstraint(Satisfaction);
11301 }
11302 }
11303 }
11304
NoteSurrogateCandidate(Sema & S,OverloadCandidate * Cand)11305 static void NoteSurrogateCandidate(Sema &S, OverloadCandidate *Cand) {
11306 if (shouldSkipNotingLambdaConversionDecl(Cand->Surrogate))
11307 return;
11308
11309 // Desugar the type of the surrogate down to a function type,
11310 // retaining as many typedefs as possible while still showing
11311 // the function type (and, therefore, its parameter types).
11312 QualType FnType = Cand->Surrogate->getConversionType();
11313 bool isLValueReference = false;
11314 bool isRValueReference = false;
11315 bool isPointer = false;
11316 if (const LValueReferenceType *FnTypeRef =
11317 FnType->getAs<LValueReferenceType>()) {
11318 FnType = FnTypeRef->getPointeeType();
11319 isLValueReference = true;
11320 } else if (const RValueReferenceType *FnTypeRef =
11321 FnType->getAs<RValueReferenceType>()) {
11322 FnType = FnTypeRef->getPointeeType();
11323 isRValueReference = true;
11324 }
11325 if (const PointerType *FnTypePtr = FnType->getAs<PointerType>()) {
11326 FnType = FnTypePtr->getPointeeType();
11327 isPointer = true;
11328 }
11329 // Desugar down to a function type.
11330 FnType = QualType(FnType->getAs<FunctionType>(), 0);
11331 // Reconstruct the pointer/reference as appropriate.
11332 if (isPointer) FnType = S.Context.getPointerType(FnType);
11333 if (isRValueReference) FnType = S.Context.getRValueReferenceType(FnType);
11334 if (isLValueReference) FnType = S.Context.getLValueReferenceType(FnType);
11335
11336 S.Diag(Cand->Surrogate->getLocation(), diag::note_ovl_surrogate_cand)
11337 << FnType;
11338 }
11339
NoteBuiltinOperatorCandidate(Sema & S,StringRef Opc,SourceLocation OpLoc,OverloadCandidate * Cand)11340 static void NoteBuiltinOperatorCandidate(Sema &S, StringRef Opc,
11341 SourceLocation OpLoc,
11342 OverloadCandidate *Cand) {
11343 assert(Cand->Conversions.size() <= 2 && "builtin operator is not binary");
11344 std::string TypeStr("operator");
11345 TypeStr += Opc;
11346 TypeStr += "(";
11347 TypeStr += Cand->BuiltinParamTypes[0].getAsString();
11348 if (Cand->Conversions.size() == 1) {
11349 TypeStr += ")";
11350 S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
11351 } else {
11352 TypeStr += ", ";
11353 TypeStr += Cand->BuiltinParamTypes[1].getAsString();
11354 TypeStr += ")";
11355 S.Diag(OpLoc, diag::note_ovl_builtin_candidate) << TypeStr;
11356 }
11357 }
11358
NoteAmbiguousUserConversions(Sema & S,SourceLocation OpLoc,OverloadCandidate * Cand)11359 static void NoteAmbiguousUserConversions(Sema &S, SourceLocation OpLoc,
11360 OverloadCandidate *Cand) {
11361 for (const ImplicitConversionSequence &ICS : Cand->Conversions) {
11362 if (ICS.isBad()) break; // all meaningless after first invalid
11363 if (!ICS.isAmbiguous()) continue;
11364
11365 ICS.DiagnoseAmbiguousConversion(
11366 S, OpLoc, S.PDiag(diag::note_ambiguous_type_conversion));
11367 }
11368 }
11369
GetLocationForCandidate(const OverloadCandidate * Cand)11370 static SourceLocation GetLocationForCandidate(const OverloadCandidate *Cand) {
11371 if (Cand->Function)
11372 return Cand->Function->getLocation();
11373 if (Cand->IsSurrogate)
11374 return Cand->Surrogate->getLocation();
11375 return SourceLocation();
11376 }
11377
RankDeductionFailure(const DeductionFailureInfo & DFI)11378 static unsigned RankDeductionFailure(const DeductionFailureInfo &DFI) {
11379 switch ((Sema::TemplateDeductionResult)DFI.Result) {
11380 case Sema::TDK_Success:
11381 case Sema::TDK_NonDependentConversionFailure:
11382 llvm_unreachable("non-deduction failure while diagnosing bad deduction");
11383
11384 case Sema::TDK_Invalid:
11385 case Sema::TDK_Incomplete:
11386 case Sema::TDK_IncompletePack:
11387 return 1;
11388
11389 case Sema::TDK_Underqualified:
11390 case Sema::TDK_Inconsistent:
11391 return 2;
11392
11393 case Sema::TDK_SubstitutionFailure:
11394 case Sema::TDK_DeducedMismatch:
11395 case Sema::TDK_ConstraintsNotSatisfied:
11396 case Sema::TDK_DeducedMismatchNested:
11397 case Sema::TDK_NonDeducedMismatch:
11398 case Sema::TDK_MiscellaneousDeductionFailure:
11399 case Sema::TDK_CUDATargetMismatch:
11400 return 3;
11401
11402 case Sema::TDK_InstantiationDepth:
11403 return 4;
11404
11405 case Sema::TDK_InvalidExplicitArguments:
11406 return 5;
11407
11408 case Sema::TDK_TooManyArguments:
11409 case Sema::TDK_TooFewArguments:
11410 return 6;
11411 }
11412 llvm_unreachable("Unhandled deduction result");
11413 }
11414
11415 namespace {
11416 struct CompareOverloadCandidatesForDisplay {
11417 Sema &S;
11418 SourceLocation Loc;
11419 size_t NumArgs;
11420 OverloadCandidateSet::CandidateSetKind CSK;
11421
CompareOverloadCandidatesForDisplay__anon5bdb524a1811::CompareOverloadCandidatesForDisplay11422 CompareOverloadCandidatesForDisplay(
11423 Sema &S, SourceLocation Loc, size_t NArgs,
11424 OverloadCandidateSet::CandidateSetKind CSK)
11425 : S(S), NumArgs(NArgs), CSK(CSK) {}
11426
EffectiveFailureKind__anon5bdb524a1811::CompareOverloadCandidatesForDisplay11427 OverloadFailureKind EffectiveFailureKind(const OverloadCandidate *C) const {
11428 // If there are too many or too few arguments, that's the high-order bit we
11429 // want to sort by, even if the immediate failure kind was something else.
11430 if (C->FailureKind == ovl_fail_too_many_arguments ||
11431 C->FailureKind == ovl_fail_too_few_arguments)
11432 return static_cast<OverloadFailureKind>(C->FailureKind);
11433
11434 if (C->Function) {
11435 if (NumArgs > C->Function->getNumParams() && !C->Function->isVariadic())
11436 return ovl_fail_too_many_arguments;
11437 if (NumArgs < C->Function->getMinRequiredArguments())
11438 return ovl_fail_too_few_arguments;
11439 }
11440
11441 return static_cast<OverloadFailureKind>(C->FailureKind);
11442 }
11443
operator ()__anon5bdb524a1811::CompareOverloadCandidatesForDisplay11444 bool operator()(const OverloadCandidate *L,
11445 const OverloadCandidate *R) {
11446 // Fast-path this check.
11447 if (L == R) return false;
11448
11449 // Order first by viability.
11450 if (L->Viable) {
11451 if (!R->Viable) return true;
11452
11453 // TODO: introduce a tri-valued comparison for overload
11454 // candidates. Would be more worthwhile if we had a sort
11455 // that could exploit it.
11456 if (isBetterOverloadCandidate(S, *L, *R, SourceLocation(), CSK))
11457 return true;
11458 if (isBetterOverloadCandidate(S, *R, *L, SourceLocation(), CSK))
11459 return false;
11460 } else if (R->Viable)
11461 return false;
11462
11463 assert(L->Viable == R->Viable);
11464
11465 // Criteria by which we can sort non-viable candidates:
11466 if (!L->Viable) {
11467 OverloadFailureKind LFailureKind = EffectiveFailureKind(L);
11468 OverloadFailureKind RFailureKind = EffectiveFailureKind(R);
11469
11470 // 1. Arity mismatches come after other candidates.
11471 if (LFailureKind == ovl_fail_too_many_arguments ||
11472 LFailureKind == ovl_fail_too_few_arguments) {
11473 if (RFailureKind == ovl_fail_too_many_arguments ||
11474 RFailureKind == ovl_fail_too_few_arguments) {
11475 int LDist = std::abs((int)L->getNumParams() - (int)NumArgs);
11476 int RDist = std::abs((int)R->getNumParams() - (int)NumArgs);
11477 if (LDist == RDist) {
11478 if (LFailureKind == RFailureKind)
11479 // Sort non-surrogates before surrogates.
11480 return !L->IsSurrogate && R->IsSurrogate;
11481 // Sort candidates requiring fewer parameters than there were
11482 // arguments given after candidates requiring more parameters
11483 // than there were arguments given.
11484 return LFailureKind == ovl_fail_too_many_arguments;
11485 }
11486 return LDist < RDist;
11487 }
11488 return false;
11489 }
11490 if (RFailureKind == ovl_fail_too_many_arguments ||
11491 RFailureKind == ovl_fail_too_few_arguments)
11492 return true;
11493
11494 // 2. Bad conversions come first and are ordered by the number
11495 // of bad conversions and quality of good conversions.
11496 if (LFailureKind == ovl_fail_bad_conversion) {
11497 if (RFailureKind != ovl_fail_bad_conversion)
11498 return true;
11499
11500 // The conversion that can be fixed with a smaller number of changes,
11501 // comes first.
11502 unsigned numLFixes = L->Fix.NumConversionsFixed;
11503 unsigned numRFixes = R->Fix.NumConversionsFixed;
11504 numLFixes = (numLFixes == 0) ? UINT_MAX : numLFixes;
11505 numRFixes = (numRFixes == 0) ? UINT_MAX : numRFixes;
11506 if (numLFixes != numRFixes) {
11507 return numLFixes < numRFixes;
11508 }
11509
11510 // If there's any ordering between the defined conversions...
11511 // FIXME: this might not be transitive.
11512 assert(L->Conversions.size() == R->Conversions.size());
11513
11514 int leftBetter = 0;
11515 unsigned I = (L->IgnoreObjectArgument || R->IgnoreObjectArgument);
11516 for (unsigned E = L->Conversions.size(); I != E; ++I) {
11517 switch (CompareImplicitConversionSequences(S, Loc,
11518 L->Conversions[I],
11519 R->Conversions[I])) {
11520 case ImplicitConversionSequence::Better:
11521 leftBetter++;
11522 break;
11523
11524 case ImplicitConversionSequence::Worse:
11525 leftBetter--;
11526 break;
11527
11528 case ImplicitConversionSequence::Indistinguishable:
11529 break;
11530 }
11531 }
11532 if (leftBetter > 0) return true;
11533 if (leftBetter < 0) return false;
11534
11535 } else if (RFailureKind == ovl_fail_bad_conversion)
11536 return false;
11537
11538 if (LFailureKind == ovl_fail_bad_deduction) {
11539 if (RFailureKind != ovl_fail_bad_deduction)
11540 return true;
11541
11542 if (L->DeductionFailure.Result != R->DeductionFailure.Result)
11543 return RankDeductionFailure(L->DeductionFailure)
11544 < RankDeductionFailure(R->DeductionFailure);
11545 } else if (RFailureKind == ovl_fail_bad_deduction)
11546 return false;
11547
11548 // TODO: others?
11549 }
11550
11551 // Sort everything else by location.
11552 SourceLocation LLoc = GetLocationForCandidate(L);
11553 SourceLocation RLoc = GetLocationForCandidate(R);
11554
11555 // Put candidates without locations (e.g. builtins) at the end.
11556 if (LLoc.isInvalid()) return false;
11557 if (RLoc.isInvalid()) return true;
11558
11559 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
11560 }
11561 };
11562 }
11563
11564 /// CompleteNonViableCandidate - Normally, overload resolution only
11565 /// computes up to the first bad conversion. Produces the FixIt set if
11566 /// possible.
11567 static void
CompleteNonViableCandidate(Sema & S,OverloadCandidate * Cand,ArrayRef<Expr * > Args,OverloadCandidateSet::CandidateSetKind CSK)11568 CompleteNonViableCandidate(Sema &S, OverloadCandidate *Cand,
11569 ArrayRef<Expr *> Args,
11570 OverloadCandidateSet::CandidateSetKind CSK) {
11571 assert(!Cand->Viable);
11572
11573 // Don't do anything on failures other than bad conversion.
11574 if (Cand->FailureKind != ovl_fail_bad_conversion)
11575 return;
11576
11577 // We only want the FixIts if all the arguments can be corrected.
11578 bool Unfixable = false;
11579 // Use a implicit copy initialization to check conversion fixes.
11580 Cand->Fix.setConversionChecker(TryCopyInitialization);
11581
11582 // Attempt to fix the bad conversion.
11583 unsigned ConvCount = Cand->Conversions.size();
11584 for (unsigned ConvIdx = (Cand->IgnoreObjectArgument ? 1 : 0); /**/;
11585 ++ConvIdx) {
11586 assert(ConvIdx != ConvCount && "no bad conversion in candidate");
11587 if (Cand->Conversions[ConvIdx].isInitialized() &&
11588 Cand->Conversions[ConvIdx].isBad()) {
11589 Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
11590 break;
11591 }
11592 }
11593
11594 // FIXME: this should probably be preserved from the overload
11595 // operation somehow.
11596 bool SuppressUserConversions = false;
11597
11598 unsigned ConvIdx = 0;
11599 unsigned ArgIdx = 0;
11600 ArrayRef<QualType> ParamTypes;
11601 bool Reversed = Cand->isReversed();
11602
11603 if (Cand->IsSurrogate) {
11604 QualType ConvType
11605 = Cand->Surrogate->getConversionType().getNonReferenceType();
11606 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
11607 ConvType = ConvPtrType->getPointeeType();
11608 ParamTypes = ConvType->castAs<FunctionProtoType>()->getParamTypes();
11609 // Conversion 0 is 'this', which doesn't have a corresponding parameter.
11610 ConvIdx = 1;
11611 } else if (Cand->Function) {
11612 ParamTypes =
11613 Cand->Function->getType()->castAs<FunctionProtoType>()->getParamTypes();
11614 if (isa<CXXMethodDecl>(Cand->Function) &&
11615 !isa<CXXConstructorDecl>(Cand->Function) && !Reversed) {
11616 // Conversion 0 is 'this', which doesn't have a corresponding parameter.
11617 ConvIdx = 1;
11618 if (CSK == OverloadCandidateSet::CSK_Operator &&
11619 Cand->Function->getDeclName().getCXXOverloadedOperator() != OO_Call)
11620 // Argument 0 is 'this', which doesn't have a corresponding parameter.
11621 ArgIdx = 1;
11622 }
11623 } else {
11624 // Builtin operator.
11625 assert(ConvCount <= 3);
11626 ParamTypes = Cand->BuiltinParamTypes;
11627 }
11628
11629 // Fill in the rest of the conversions.
11630 for (unsigned ParamIdx = Reversed ? ParamTypes.size() - 1 : 0;
11631 ConvIdx != ConvCount;
11632 ++ConvIdx, ++ArgIdx, ParamIdx += (Reversed ? -1 : 1)) {
11633 assert(ArgIdx < Args.size() && "no argument for this arg conversion");
11634 if (Cand->Conversions[ConvIdx].isInitialized()) {
11635 // We've already checked this conversion.
11636 } else if (ParamIdx < ParamTypes.size()) {
11637 if (ParamTypes[ParamIdx]->isDependentType())
11638 Cand->Conversions[ConvIdx].setAsIdentityConversion(
11639 Args[ArgIdx]->getType());
11640 else {
11641 Cand->Conversions[ConvIdx] =
11642 TryCopyInitialization(S, Args[ArgIdx], ParamTypes[ParamIdx],
11643 SuppressUserConversions,
11644 /*InOverloadResolution=*/true,
11645 /*AllowObjCWritebackConversion=*/
11646 S.getLangOpts().ObjCAutoRefCount);
11647 // Store the FixIt in the candidate if it exists.
11648 if (!Unfixable && Cand->Conversions[ConvIdx].isBad())
11649 Unfixable = !Cand->TryToFixBadConversion(ConvIdx, S);
11650 }
11651 } else
11652 Cand->Conversions[ConvIdx].setEllipsis();
11653 }
11654 }
11655
CompleteCandidates(Sema & S,OverloadCandidateDisplayKind OCD,ArrayRef<Expr * > Args,SourceLocation OpLoc,llvm::function_ref<bool (OverloadCandidate &)> Filter)11656 SmallVector<OverloadCandidate *, 32> OverloadCandidateSet::CompleteCandidates(
11657 Sema &S, OverloadCandidateDisplayKind OCD, ArrayRef<Expr *> Args,
11658 SourceLocation OpLoc,
11659 llvm::function_ref<bool(OverloadCandidate &)> Filter) {
11660 // Sort the candidates by viability and position. Sorting directly would
11661 // be prohibitive, so we make a set of pointers and sort those.
11662 SmallVector<OverloadCandidate*, 32> Cands;
11663 if (OCD == OCD_AllCandidates) Cands.reserve(size());
11664 for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
11665 if (!Filter(*Cand))
11666 continue;
11667 switch (OCD) {
11668 case OCD_AllCandidates:
11669 if (!Cand->Viable) {
11670 if (!Cand->Function && !Cand->IsSurrogate) {
11671 // This a non-viable builtin candidate. We do not, in general,
11672 // want to list every possible builtin candidate.
11673 continue;
11674 }
11675 CompleteNonViableCandidate(S, Cand, Args, Kind);
11676 }
11677 break;
11678
11679 case OCD_ViableCandidates:
11680 if (!Cand->Viable)
11681 continue;
11682 break;
11683
11684 case OCD_AmbiguousCandidates:
11685 if (!Cand->Best)
11686 continue;
11687 break;
11688 }
11689
11690 Cands.push_back(Cand);
11691 }
11692
11693 llvm::stable_sort(
11694 Cands, CompareOverloadCandidatesForDisplay(S, OpLoc, Args.size(), Kind));
11695
11696 return Cands;
11697 }
11698
shouldDeferDiags(Sema & S,ArrayRef<Expr * > Args,SourceLocation OpLoc)11699 bool OverloadCandidateSet::shouldDeferDiags(Sema &S, ArrayRef<Expr *> Args,
11700 SourceLocation OpLoc) {
11701 bool DeferHint = false;
11702 if (S.getLangOpts().CUDA && S.getLangOpts().GPUDeferDiag) {
11703 // Defer diagnostic for CUDA/HIP if there are wrong-sided candidates or
11704 // host device candidates.
11705 auto WrongSidedCands =
11706 CompleteCandidates(S, OCD_AllCandidates, Args, OpLoc, [](auto &Cand) {
11707 return (Cand.Viable == false &&
11708 Cand.FailureKind == ovl_fail_bad_target) ||
11709 (Cand.Function &&
11710 Cand.Function->template hasAttr<CUDAHostAttr>() &&
11711 Cand.Function->template hasAttr<CUDADeviceAttr>());
11712 });
11713 DeferHint = !WrongSidedCands.empty();
11714 }
11715 return DeferHint;
11716 }
11717
11718 /// When overload resolution fails, prints diagnostic messages containing the
11719 /// candidates in the candidate set.
NoteCandidates(PartialDiagnosticAt PD,Sema & S,OverloadCandidateDisplayKind OCD,ArrayRef<Expr * > Args,StringRef Opc,SourceLocation OpLoc,llvm::function_ref<bool (OverloadCandidate &)> Filter)11720 void OverloadCandidateSet::NoteCandidates(
11721 PartialDiagnosticAt PD, Sema &S, OverloadCandidateDisplayKind OCD,
11722 ArrayRef<Expr *> Args, StringRef Opc, SourceLocation OpLoc,
11723 llvm::function_ref<bool(OverloadCandidate &)> Filter) {
11724
11725 auto Cands = CompleteCandidates(S, OCD, Args, OpLoc, Filter);
11726
11727 S.Diag(PD.first, PD.second, shouldDeferDiags(S, Args, OpLoc));
11728
11729 NoteCandidates(S, Args, Cands, Opc, OpLoc);
11730
11731 if (OCD == OCD_AmbiguousCandidates)
11732 MaybeDiagnoseAmbiguousConstraints(S, {begin(), end()});
11733 }
11734
NoteCandidates(Sema & S,ArrayRef<Expr * > Args,ArrayRef<OverloadCandidate * > Cands,StringRef Opc,SourceLocation OpLoc)11735 void OverloadCandidateSet::NoteCandidates(Sema &S, ArrayRef<Expr *> Args,
11736 ArrayRef<OverloadCandidate *> Cands,
11737 StringRef Opc, SourceLocation OpLoc) {
11738 bool ReportedAmbiguousConversions = false;
11739
11740 const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
11741 unsigned CandsShown = 0;
11742 auto I = Cands.begin(), E = Cands.end();
11743 for (; I != E; ++I) {
11744 OverloadCandidate *Cand = *I;
11745
11746 if (CandsShown >= S.Diags.getNumOverloadCandidatesToShow() &&
11747 ShowOverloads == Ovl_Best) {
11748 break;
11749 }
11750 ++CandsShown;
11751
11752 if (Cand->Function)
11753 NoteFunctionCandidate(S, Cand, Args.size(),
11754 /*TakingCandidateAddress=*/false, DestAS);
11755 else if (Cand->IsSurrogate)
11756 NoteSurrogateCandidate(S, Cand);
11757 else {
11758 assert(Cand->Viable &&
11759 "Non-viable built-in candidates are not added to Cands.");
11760 // Generally we only see ambiguities including viable builtin
11761 // operators if overload resolution got screwed up by an
11762 // ambiguous user-defined conversion.
11763 //
11764 // FIXME: It's quite possible for different conversions to see
11765 // different ambiguities, though.
11766 if (!ReportedAmbiguousConversions) {
11767 NoteAmbiguousUserConversions(S, OpLoc, Cand);
11768 ReportedAmbiguousConversions = true;
11769 }
11770
11771 // If this is a viable builtin, print it.
11772 NoteBuiltinOperatorCandidate(S, Opc, OpLoc, Cand);
11773 }
11774 }
11775
11776 // Inform S.Diags that we've shown an overload set with N elements. This may
11777 // inform the future value of S.Diags.getNumOverloadCandidatesToShow().
11778 S.Diags.overloadCandidatesShown(CandsShown);
11779
11780 if (I != E)
11781 S.Diag(OpLoc, diag::note_ovl_too_many_candidates,
11782 shouldDeferDiags(S, Args, OpLoc))
11783 << int(E - I);
11784 }
11785
11786 static SourceLocation
GetLocationForCandidate(const TemplateSpecCandidate * Cand)11787 GetLocationForCandidate(const TemplateSpecCandidate *Cand) {
11788 return Cand->Specialization ? Cand->Specialization->getLocation()
11789 : SourceLocation();
11790 }
11791
11792 namespace {
11793 struct CompareTemplateSpecCandidatesForDisplay {
11794 Sema &S;
CompareTemplateSpecCandidatesForDisplay__anon5bdb524a1a11::CompareTemplateSpecCandidatesForDisplay11795 CompareTemplateSpecCandidatesForDisplay(Sema &S) : S(S) {}
11796
operator ()__anon5bdb524a1a11::CompareTemplateSpecCandidatesForDisplay11797 bool operator()(const TemplateSpecCandidate *L,
11798 const TemplateSpecCandidate *R) {
11799 // Fast-path this check.
11800 if (L == R)
11801 return false;
11802
11803 // Assuming that both candidates are not matches...
11804
11805 // Sort by the ranking of deduction failures.
11806 if (L->DeductionFailure.Result != R->DeductionFailure.Result)
11807 return RankDeductionFailure(L->DeductionFailure) <
11808 RankDeductionFailure(R->DeductionFailure);
11809
11810 // Sort everything else by location.
11811 SourceLocation LLoc = GetLocationForCandidate(L);
11812 SourceLocation RLoc = GetLocationForCandidate(R);
11813
11814 // Put candidates without locations (e.g. builtins) at the end.
11815 if (LLoc.isInvalid())
11816 return false;
11817 if (RLoc.isInvalid())
11818 return true;
11819
11820 return S.SourceMgr.isBeforeInTranslationUnit(LLoc, RLoc);
11821 }
11822 };
11823 }
11824
11825 /// Diagnose a template argument deduction failure.
11826 /// We are treating these failures as overload failures due to bad
11827 /// deductions.
NoteDeductionFailure(Sema & S,bool ForTakingAddress)11828 void TemplateSpecCandidate::NoteDeductionFailure(Sema &S,
11829 bool ForTakingAddress) {
11830 DiagnoseBadDeduction(S, FoundDecl, Specialization, // pattern
11831 DeductionFailure, /*NumArgs=*/0, ForTakingAddress);
11832 }
11833
destroyCandidates()11834 void TemplateSpecCandidateSet::destroyCandidates() {
11835 for (iterator i = begin(), e = end(); i != e; ++i) {
11836 i->DeductionFailure.Destroy();
11837 }
11838 }
11839
clear()11840 void TemplateSpecCandidateSet::clear() {
11841 destroyCandidates();
11842 Candidates.clear();
11843 }
11844
11845 /// NoteCandidates - When no template specialization match is found, prints
11846 /// diagnostic messages containing the non-matching specializations that form
11847 /// the candidate set.
11848 /// This is analoguous to OverloadCandidateSet::NoteCandidates() with
11849 /// OCD == OCD_AllCandidates and Cand->Viable == false.
NoteCandidates(Sema & S,SourceLocation Loc)11850 void TemplateSpecCandidateSet::NoteCandidates(Sema &S, SourceLocation Loc) {
11851 // Sort the candidates by position (assuming no candidate is a match).
11852 // Sorting directly would be prohibitive, so we make a set of pointers
11853 // and sort those.
11854 SmallVector<TemplateSpecCandidate *, 32> Cands;
11855 Cands.reserve(size());
11856 for (iterator Cand = begin(), LastCand = end(); Cand != LastCand; ++Cand) {
11857 if (Cand->Specialization)
11858 Cands.push_back(Cand);
11859 // Otherwise, this is a non-matching builtin candidate. We do not,
11860 // in general, want to list every possible builtin candidate.
11861 }
11862
11863 llvm::sort(Cands, CompareTemplateSpecCandidatesForDisplay(S));
11864
11865 // FIXME: Perhaps rename OverloadsShown and getShowOverloads()
11866 // for generalization purposes (?).
11867 const OverloadsShown ShowOverloads = S.Diags.getShowOverloads();
11868
11869 SmallVectorImpl<TemplateSpecCandidate *>::iterator I, E;
11870 unsigned CandsShown = 0;
11871 for (I = Cands.begin(), E = Cands.end(); I != E; ++I) {
11872 TemplateSpecCandidate *Cand = *I;
11873
11874 // Set an arbitrary limit on the number of candidates we'll spam
11875 // the user with. FIXME: This limit should depend on details of the
11876 // candidate list.
11877 if (CandsShown >= 4 && ShowOverloads == Ovl_Best)
11878 break;
11879 ++CandsShown;
11880
11881 assert(Cand->Specialization &&
11882 "Non-matching built-in candidates are not added to Cands.");
11883 Cand->NoteDeductionFailure(S, ForTakingAddress);
11884 }
11885
11886 if (I != E)
11887 S.Diag(Loc, diag::note_ovl_too_many_candidates) << int(E - I);
11888 }
11889
11890 // [PossiblyAFunctionType] --> [Return]
11891 // NonFunctionType --> NonFunctionType
11892 // R (A) --> R(A)
11893 // R (*)(A) --> R (A)
11894 // R (&)(A) --> R (A)
11895 // R (S::*)(A) --> R (A)
ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType)11896 QualType Sema::ExtractUnqualifiedFunctionType(QualType PossiblyAFunctionType) {
11897 QualType Ret = PossiblyAFunctionType;
11898 if (const PointerType *ToTypePtr =
11899 PossiblyAFunctionType->getAs<PointerType>())
11900 Ret = ToTypePtr->getPointeeType();
11901 else if (const ReferenceType *ToTypeRef =
11902 PossiblyAFunctionType->getAs<ReferenceType>())
11903 Ret = ToTypeRef->getPointeeType();
11904 else if (const MemberPointerType *MemTypePtr =
11905 PossiblyAFunctionType->getAs<MemberPointerType>())
11906 Ret = MemTypePtr->getPointeeType();
11907 Ret =
11908 Context.getCanonicalType(Ret).getUnqualifiedType();
11909 return Ret;
11910 }
11911
completeFunctionType(Sema & S,FunctionDecl * FD,SourceLocation Loc,bool Complain=true)11912 static bool completeFunctionType(Sema &S, FunctionDecl *FD, SourceLocation Loc,
11913 bool Complain = true) {
11914 if (S.getLangOpts().CPlusPlus14 && FD->getReturnType()->isUndeducedType() &&
11915 S.DeduceReturnType(FD, Loc, Complain))
11916 return true;
11917
11918 auto *FPT = FD->getType()->castAs<FunctionProtoType>();
11919 if (S.getLangOpts().CPlusPlus17 &&
11920 isUnresolvedExceptionSpec(FPT->getExceptionSpecType()) &&
11921 !S.ResolveExceptionSpec(Loc, FPT))
11922 return true;
11923
11924 return false;
11925 }
11926
11927 namespace {
11928 // A helper class to help with address of function resolution
11929 // - allows us to avoid passing around all those ugly parameters
11930 class AddressOfFunctionResolver {
11931 Sema& S;
11932 Expr* SourceExpr;
11933 const QualType& TargetType;
11934 QualType TargetFunctionType; // Extracted function type from target type
11935
11936 bool Complain;
11937 //DeclAccessPair& ResultFunctionAccessPair;
11938 ASTContext& Context;
11939
11940 bool TargetTypeIsNonStaticMemberFunction;
11941 bool FoundNonTemplateFunction;
11942 bool StaticMemberFunctionFromBoundPointer;
11943 bool HasComplained;
11944
11945 OverloadExpr::FindResult OvlExprInfo;
11946 OverloadExpr *OvlExpr;
11947 TemplateArgumentListInfo OvlExplicitTemplateArgs;
11948 SmallVector<std::pair<DeclAccessPair, FunctionDecl*>, 4> Matches;
11949 TemplateSpecCandidateSet FailedCandidates;
11950
11951 public:
AddressOfFunctionResolver(Sema & S,Expr * SourceExpr,const QualType & TargetType,bool Complain)11952 AddressOfFunctionResolver(Sema &S, Expr *SourceExpr,
11953 const QualType &TargetType, bool Complain)
11954 : S(S), SourceExpr(SourceExpr), TargetType(TargetType),
11955 Complain(Complain), Context(S.getASTContext()),
11956 TargetTypeIsNonStaticMemberFunction(
11957 !!TargetType->getAs<MemberPointerType>()),
11958 FoundNonTemplateFunction(false),
11959 StaticMemberFunctionFromBoundPointer(false),
11960 HasComplained(false),
11961 OvlExprInfo(OverloadExpr::find(SourceExpr)),
11962 OvlExpr(OvlExprInfo.Expression),
11963 FailedCandidates(OvlExpr->getNameLoc(), /*ForTakingAddress=*/true) {
11964 ExtractUnqualifiedFunctionTypeFromTargetType();
11965
11966 if (TargetFunctionType->isFunctionType()) {
11967 if (UnresolvedMemberExpr *UME = dyn_cast<UnresolvedMemberExpr>(OvlExpr))
11968 if (!UME->isImplicitAccess() &&
11969 !S.ResolveSingleFunctionTemplateSpecialization(UME))
11970 StaticMemberFunctionFromBoundPointer = true;
11971 } else if (OvlExpr->hasExplicitTemplateArgs()) {
11972 DeclAccessPair dap;
11973 if (FunctionDecl *Fn = S.ResolveSingleFunctionTemplateSpecialization(
11974 OvlExpr, false, &dap)) {
11975 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
11976 if (!Method->isStatic()) {
11977 // If the target type is a non-function type and the function found
11978 // is a non-static member function, pretend as if that was the
11979 // target, it's the only possible type to end up with.
11980 TargetTypeIsNonStaticMemberFunction = true;
11981
11982 // And skip adding the function if its not in the proper form.
11983 // We'll diagnose this due to an empty set of functions.
11984 if (!OvlExprInfo.HasFormOfMemberPointer)
11985 return;
11986 }
11987
11988 Matches.push_back(std::make_pair(dap, Fn));
11989 }
11990 return;
11991 }
11992
11993 if (OvlExpr->hasExplicitTemplateArgs())
11994 OvlExpr->copyTemplateArgumentsInto(OvlExplicitTemplateArgs);
11995
11996 if (FindAllFunctionsThatMatchTargetTypeExactly()) {
11997 // C++ [over.over]p4:
11998 // If more than one function is selected, [...]
11999 if (Matches.size() > 1 && !eliminiateSuboptimalOverloadCandidates()) {
12000 if (FoundNonTemplateFunction)
12001 EliminateAllTemplateMatches();
12002 else
12003 EliminateAllExceptMostSpecializedTemplate();
12004 }
12005 }
12006
12007 if (S.getLangOpts().CUDA && Matches.size() > 1)
12008 EliminateSuboptimalCudaMatches();
12009 }
12010
hasComplained() const12011 bool hasComplained() const { return HasComplained; }
12012
12013 private:
candidateHasExactlyCorrectType(const FunctionDecl * FD)12014 bool candidateHasExactlyCorrectType(const FunctionDecl *FD) {
12015 QualType Discard;
12016 return Context.hasSameUnqualifiedType(TargetFunctionType, FD->getType()) ||
12017 S.IsFunctionConversion(FD->getType(), TargetFunctionType, Discard);
12018 }
12019
12020 /// \return true if A is considered a better overload candidate for the
12021 /// desired type than B.
isBetterCandidate(const FunctionDecl * A,const FunctionDecl * B)12022 bool isBetterCandidate(const FunctionDecl *A, const FunctionDecl *B) {
12023 // If A doesn't have exactly the correct type, we don't want to classify it
12024 // as "better" than anything else. This way, the user is required to
12025 // disambiguate for us if there are multiple candidates and no exact match.
12026 return candidateHasExactlyCorrectType(A) &&
12027 (!candidateHasExactlyCorrectType(B) ||
12028 compareEnableIfAttrs(S, A, B) == Comparison::Better);
12029 }
12030
12031 /// \return true if we were able to eliminate all but one overload candidate,
12032 /// false otherwise.
eliminiateSuboptimalOverloadCandidates()12033 bool eliminiateSuboptimalOverloadCandidates() {
12034 // Same algorithm as overload resolution -- one pass to pick the "best",
12035 // another pass to be sure that nothing is better than the best.
12036 auto Best = Matches.begin();
12037 for (auto I = Matches.begin()+1, E = Matches.end(); I != E; ++I)
12038 if (isBetterCandidate(I->second, Best->second))
12039 Best = I;
12040
12041 const FunctionDecl *BestFn = Best->second;
12042 auto IsBestOrInferiorToBest = [this, BestFn](
12043 const std::pair<DeclAccessPair, FunctionDecl *> &Pair) {
12044 return BestFn == Pair.second || isBetterCandidate(BestFn, Pair.second);
12045 };
12046
12047 // Note: We explicitly leave Matches unmodified if there isn't a clear best
12048 // option, so we can potentially give the user a better error
12049 if (!llvm::all_of(Matches, IsBestOrInferiorToBest))
12050 return false;
12051 Matches[0] = *Best;
12052 Matches.resize(1);
12053 return true;
12054 }
12055
isTargetTypeAFunction() const12056 bool isTargetTypeAFunction() const {
12057 return TargetFunctionType->isFunctionType();
12058 }
12059
12060 // [ToType] [Return]
12061
12062 // R (*)(A) --> R (A), IsNonStaticMemberFunction = false
12063 // R (&)(A) --> R (A), IsNonStaticMemberFunction = false
12064 // R (S::*)(A) --> R (A), IsNonStaticMemberFunction = true
ExtractUnqualifiedFunctionTypeFromTargetType()12065 void inline ExtractUnqualifiedFunctionTypeFromTargetType() {
12066 TargetFunctionType = S.ExtractUnqualifiedFunctionType(TargetType);
12067 }
12068
12069 // return true if any matching specializations were found
AddMatchingTemplateFunction(FunctionTemplateDecl * FunctionTemplate,const DeclAccessPair & CurAccessFunPair)12070 bool AddMatchingTemplateFunction(FunctionTemplateDecl* FunctionTemplate,
12071 const DeclAccessPair& CurAccessFunPair) {
12072 if (CXXMethodDecl *Method
12073 = dyn_cast<CXXMethodDecl>(FunctionTemplate->getTemplatedDecl())) {
12074 // Skip non-static function templates when converting to pointer, and
12075 // static when converting to member pointer.
12076 if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
12077 return false;
12078 }
12079 else if (TargetTypeIsNonStaticMemberFunction)
12080 return false;
12081
12082 // C++ [over.over]p2:
12083 // If the name is a function template, template argument deduction is
12084 // done (14.8.2.2), and if the argument deduction succeeds, the
12085 // resulting template argument list is used to generate a single
12086 // function template specialization, which is added to the set of
12087 // overloaded functions considered.
12088 FunctionDecl *Specialization = nullptr;
12089 TemplateDeductionInfo Info(FailedCandidates.getLocation());
12090 if (Sema::TemplateDeductionResult Result
12091 = S.DeduceTemplateArguments(FunctionTemplate,
12092 &OvlExplicitTemplateArgs,
12093 TargetFunctionType, Specialization,
12094 Info, /*IsAddressOfFunction*/true)) {
12095 // Make a note of the failed deduction for diagnostics.
12096 FailedCandidates.addCandidate()
12097 .set(CurAccessFunPair, FunctionTemplate->getTemplatedDecl(),
12098 MakeDeductionFailureInfo(Context, Result, Info));
12099 return false;
12100 }
12101
12102 // Template argument deduction ensures that we have an exact match or
12103 // compatible pointer-to-function arguments that would be adjusted by ICS.
12104 // This function template specicalization works.
12105 assert(S.isSameOrCompatibleFunctionType(
12106 Context.getCanonicalType(Specialization->getType()),
12107 Context.getCanonicalType(TargetFunctionType)));
12108
12109 if (!S.checkAddressOfFunctionIsAvailable(Specialization))
12110 return false;
12111
12112 Matches.push_back(std::make_pair(CurAccessFunPair, Specialization));
12113 return true;
12114 }
12115
AddMatchingNonTemplateFunction(NamedDecl * Fn,const DeclAccessPair & CurAccessFunPair)12116 bool AddMatchingNonTemplateFunction(NamedDecl* Fn,
12117 const DeclAccessPair& CurAccessFunPair) {
12118 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
12119 // Skip non-static functions when converting to pointer, and static
12120 // when converting to member pointer.
12121 if (Method->isStatic() == TargetTypeIsNonStaticMemberFunction)
12122 return false;
12123 }
12124 else if (TargetTypeIsNonStaticMemberFunction)
12125 return false;
12126
12127 if (FunctionDecl *FunDecl = dyn_cast<FunctionDecl>(Fn)) {
12128 if (S.getLangOpts().CUDA)
12129 if (FunctionDecl *Caller = dyn_cast<FunctionDecl>(S.CurContext))
12130 if (!Caller->isImplicit() && !S.IsAllowedCUDACall(Caller, FunDecl))
12131 return false;
12132 if (FunDecl->isMultiVersion()) {
12133 const auto *TA = FunDecl->getAttr<TargetAttr>();
12134 if (TA && !TA->isDefaultVersion())
12135 return false;
12136 }
12137
12138 // If any candidate has a placeholder return type, trigger its deduction
12139 // now.
12140 if (completeFunctionType(S, FunDecl, SourceExpr->getBeginLoc(),
12141 Complain)) {
12142 HasComplained |= Complain;
12143 return false;
12144 }
12145
12146 if (!S.checkAddressOfFunctionIsAvailable(FunDecl))
12147 return false;
12148
12149 // If we're in C, we need to support types that aren't exactly identical.
12150 if (!S.getLangOpts().CPlusPlus ||
12151 candidateHasExactlyCorrectType(FunDecl)) {
12152 Matches.push_back(std::make_pair(
12153 CurAccessFunPair, cast<FunctionDecl>(FunDecl->getCanonicalDecl())));
12154 FoundNonTemplateFunction = true;
12155 return true;
12156 }
12157 }
12158
12159 return false;
12160 }
12161
FindAllFunctionsThatMatchTargetTypeExactly()12162 bool FindAllFunctionsThatMatchTargetTypeExactly() {
12163 bool Ret = false;
12164
12165 // If the overload expression doesn't have the form of a pointer to
12166 // member, don't try to convert it to a pointer-to-member type.
12167 if (IsInvalidFormOfPointerToMemberFunction())
12168 return false;
12169
12170 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
12171 E = OvlExpr->decls_end();
12172 I != E; ++I) {
12173 // Look through any using declarations to find the underlying function.
12174 NamedDecl *Fn = (*I)->getUnderlyingDecl();
12175
12176 // C++ [over.over]p3:
12177 // Non-member functions and static member functions match
12178 // targets of type "pointer-to-function" or "reference-to-function."
12179 // Nonstatic member functions match targets of
12180 // type "pointer-to-member-function."
12181 // Note that according to DR 247, the containing class does not matter.
12182 if (FunctionTemplateDecl *FunctionTemplate
12183 = dyn_cast<FunctionTemplateDecl>(Fn)) {
12184 if (AddMatchingTemplateFunction(FunctionTemplate, I.getPair()))
12185 Ret = true;
12186 }
12187 // If we have explicit template arguments supplied, skip non-templates.
12188 else if (!OvlExpr->hasExplicitTemplateArgs() &&
12189 AddMatchingNonTemplateFunction(Fn, I.getPair()))
12190 Ret = true;
12191 }
12192 assert(Ret || Matches.empty());
12193 return Ret;
12194 }
12195
EliminateAllExceptMostSpecializedTemplate()12196 void EliminateAllExceptMostSpecializedTemplate() {
12197 // [...] and any given function template specialization F1 is
12198 // eliminated if the set contains a second function template
12199 // specialization whose function template is more specialized
12200 // than the function template of F1 according to the partial
12201 // ordering rules of 14.5.5.2.
12202
12203 // The algorithm specified above is quadratic. We instead use a
12204 // two-pass algorithm (similar to the one used to identify the
12205 // best viable function in an overload set) that identifies the
12206 // best function template (if it exists).
12207
12208 UnresolvedSet<4> MatchesCopy; // TODO: avoid!
12209 for (unsigned I = 0, E = Matches.size(); I != E; ++I)
12210 MatchesCopy.addDecl(Matches[I].second, Matches[I].first.getAccess());
12211
12212 // TODO: It looks like FailedCandidates does not serve much purpose
12213 // here, since the no_viable diagnostic has index 0.
12214 UnresolvedSetIterator Result = S.getMostSpecialized(
12215 MatchesCopy.begin(), MatchesCopy.end(), FailedCandidates,
12216 SourceExpr->getBeginLoc(), S.PDiag(),
12217 S.PDiag(diag::err_addr_ovl_ambiguous)
12218 << Matches[0].second->getDeclName(),
12219 S.PDiag(diag::note_ovl_candidate)
12220 << (unsigned)oc_function << (unsigned)ocs_described_template,
12221 Complain, TargetFunctionType);
12222
12223 if (Result != MatchesCopy.end()) {
12224 // Make it the first and only element
12225 Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
12226 Matches[0].second = cast<FunctionDecl>(*Result);
12227 Matches.resize(1);
12228 } else
12229 HasComplained |= Complain;
12230 }
12231
EliminateAllTemplateMatches()12232 void EliminateAllTemplateMatches() {
12233 // [...] any function template specializations in the set are
12234 // eliminated if the set also contains a non-template function, [...]
12235 for (unsigned I = 0, N = Matches.size(); I != N; ) {
12236 if (Matches[I].second->getPrimaryTemplate() == nullptr)
12237 ++I;
12238 else {
12239 Matches[I] = Matches[--N];
12240 Matches.resize(N);
12241 }
12242 }
12243 }
12244
EliminateSuboptimalCudaMatches()12245 void EliminateSuboptimalCudaMatches() {
12246 S.EraseUnwantedCUDAMatches(dyn_cast<FunctionDecl>(S.CurContext), Matches);
12247 }
12248
12249 public:
ComplainNoMatchesFound() const12250 void ComplainNoMatchesFound() const {
12251 assert(Matches.empty());
12252 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_no_viable)
12253 << OvlExpr->getName() << TargetFunctionType
12254 << OvlExpr->getSourceRange();
12255 if (FailedCandidates.empty())
12256 S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
12257 /*TakingAddress=*/true);
12258 else {
12259 // We have some deduction failure messages. Use them to diagnose
12260 // the function templates, and diagnose the non-template candidates
12261 // normally.
12262 for (UnresolvedSetIterator I = OvlExpr->decls_begin(),
12263 IEnd = OvlExpr->decls_end();
12264 I != IEnd; ++I)
12265 if (FunctionDecl *Fun =
12266 dyn_cast<FunctionDecl>((*I)->getUnderlyingDecl()))
12267 if (!functionHasPassObjectSizeParams(Fun))
12268 S.NoteOverloadCandidate(*I, Fun, CRK_None, TargetFunctionType,
12269 /*TakingAddress=*/true);
12270 FailedCandidates.NoteCandidates(S, OvlExpr->getBeginLoc());
12271 }
12272 }
12273
IsInvalidFormOfPointerToMemberFunction() const12274 bool IsInvalidFormOfPointerToMemberFunction() const {
12275 return TargetTypeIsNonStaticMemberFunction &&
12276 !OvlExprInfo.HasFormOfMemberPointer;
12277 }
12278
ComplainIsInvalidFormOfPointerToMemberFunction() const12279 void ComplainIsInvalidFormOfPointerToMemberFunction() const {
12280 // TODO: Should we condition this on whether any functions might
12281 // have matched, or is it more appropriate to do that in callers?
12282 // TODO: a fixit wouldn't hurt.
12283 S.Diag(OvlExpr->getNameLoc(), diag::err_addr_ovl_no_qualifier)
12284 << TargetType << OvlExpr->getSourceRange();
12285 }
12286
IsStaticMemberFunctionFromBoundPointer() const12287 bool IsStaticMemberFunctionFromBoundPointer() const {
12288 return StaticMemberFunctionFromBoundPointer;
12289 }
12290
ComplainIsStaticMemberFunctionFromBoundPointer() const12291 void ComplainIsStaticMemberFunctionFromBoundPointer() const {
12292 S.Diag(OvlExpr->getBeginLoc(),
12293 diag::err_invalid_form_pointer_member_function)
12294 << OvlExpr->getSourceRange();
12295 }
12296
ComplainOfInvalidConversion() const12297 void ComplainOfInvalidConversion() const {
12298 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_not_func_ptrref)
12299 << OvlExpr->getName() << TargetType;
12300 }
12301
ComplainMultipleMatchesFound() const12302 void ComplainMultipleMatchesFound() const {
12303 assert(Matches.size() > 1);
12304 S.Diag(OvlExpr->getBeginLoc(), diag::err_addr_ovl_ambiguous)
12305 << OvlExpr->getName() << OvlExpr->getSourceRange();
12306 S.NoteAllOverloadCandidates(OvlExpr, TargetFunctionType,
12307 /*TakingAddress=*/true);
12308 }
12309
hadMultipleCandidates() const12310 bool hadMultipleCandidates() const { return (OvlExpr->getNumDecls() > 1); }
12311
getNumMatches() const12312 int getNumMatches() const { return Matches.size(); }
12313
getMatchingFunctionDecl() const12314 FunctionDecl* getMatchingFunctionDecl() const {
12315 if (Matches.size() != 1) return nullptr;
12316 return Matches[0].second;
12317 }
12318
getMatchingFunctionAccessPair() const12319 const DeclAccessPair* getMatchingFunctionAccessPair() const {
12320 if (Matches.size() != 1) return nullptr;
12321 return &Matches[0].first;
12322 }
12323 };
12324 }
12325
12326 /// ResolveAddressOfOverloadedFunction - Try to resolve the address of
12327 /// an overloaded function (C++ [over.over]), where @p From is an
12328 /// expression with overloaded function type and @p ToType is the type
12329 /// we're trying to resolve to. For example:
12330 ///
12331 /// @code
12332 /// int f(double);
12333 /// int f(int);
12334 ///
12335 /// int (*pfd)(double) = f; // selects f(double)
12336 /// @endcode
12337 ///
12338 /// This routine returns the resulting FunctionDecl if it could be
12339 /// resolved, and NULL otherwise. When @p Complain is true, this
12340 /// routine will emit diagnostics if there is an error.
12341 FunctionDecl *
ResolveAddressOfOverloadedFunction(Expr * AddressOfExpr,QualType TargetType,bool Complain,DeclAccessPair & FoundResult,bool * pHadMultipleCandidates)12342 Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
12343 QualType TargetType,
12344 bool Complain,
12345 DeclAccessPair &FoundResult,
12346 bool *pHadMultipleCandidates) {
12347 assert(AddressOfExpr->getType() == Context.OverloadTy);
12348
12349 AddressOfFunctionResolver Resolver(*this, AddressOfExpr, TargetType,
12350 Complain);
12351 int NumMatches = Resolver.getNumMatches();
12352 FunctionDecl *Fn = nullptr;
12353 bool ShouldComplain = Complain && !Resolver.hasComplained();
12354 if (NumMatches == 0 && ShouldComplain) {
12355 if (Resolver.IsInvalidFormOfPointerToMemberFunction())
12356 Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
12357 else
12358 Resolver.ComplainNoMatchesFound();
12359 }
12360 else if (NumMatches > 1 && ShouldComplain)
12361 Resolver.ComplainMultipleMatchesFound();
12362 else if (NumMatches == 1) {
12363 Fn = Resolver.getMatchingFunctionDecl();
12364 assert(Fn);
12365 if (auto *FPT = Fn->getType()->getAs<FunctionProtoType>())
12366 ResolveExceptionSpec(AddressOfExpr->getExprLoc(), FPT);
12367 FoundResult = *Resolver.getMatchingFunctionAccessPair();
12368 if (Complain) {
12369 if (Resolver.IsStaticMemberFunctionFromBoundPointer())
12370 Resolver.ComplainIsStaticMemberFunctionFromBoundPointer();
12371 else
12372 CheckAddressOfMemberAccess(AddressOfExpr, FoundResult);
12373 }
12374 }
12375
12376 if (pHadMultipleCandidates)
12377 *pHadMultipleCandidates = Resolver.hadMultipleCandidates();
12378 return Fn;
12379 }
12380
12381 /// Given an expression that refers to an overloaded function, try to
12382 /// resolve that function to a single function that can have its address taken.
12383 /// This will modify `Pair` iff it returns non-null.
12384 ///
12385 /// This routine can only succeed if from all of the candidates in the overload
12386 /// set for SrcExpr that can have their addresses taken, there is one candidate
12387 /// that is more constrained than the rest.
12388 FunctionDecl *
resolveAddressOfSingleOverloadCandidate(Expr * E,DeclAccessPair & Pair)12389 Sema::resolveAddressOfSingleOverloadCandidate(Expr *E, DeclAccessPair &Pair) {
12390 OverloadExpr::FindResult R = OverloadExpr::find(E);
12391 OverloadExpr *Ovl = R.Expression;
12392 bool IsResultAmbiguous = false;
12393 FunctionDecl *Result = nullptr;
12394 DeclAccessPair DAP;
12395 SmallVector<FunctionDecl *, 2> AmbiguousDecls;
12396
12397 auto CheckMoreConstrained =
12398 [&] (FunctionDecl *FD1, FunctionDecl *FD2) -> Optional<bool> {
12399 SmallVector<const Expr *, 1> AC1, AC2;
12400 FD1->getAssociatedConstraints(AC1);
12401 FD2->getAssociatedConstraints(AC2);
12402 bool AtLeastAsConstrained1, AtLeastAsConstrained2;
12403 if (IsAtLeastAsConstrained(FD1, AC1, FD2, AC2, AtLeastAsConstrained1))
12404 return None;
12405 if (IsAtLeastAsConstrained(FD2, AC2, FD1, AC1, AtLeastAsConstrained2))
12406 return None;
12407 if (AtLeastAsConstrained1 == AtLeastAsConstrained2)
12408 return None;
12409 return AtLeastAsConstrained1;
12410 };
12411
12412 // Don't use the AddressOfResolver because we're specifically looking for
12413 // cases where we have one overload candidate that lacks
12414 // enable_if/pass_object_size/...
12415 for (auto I = Ovl->decls_begin(), E = Ovl->decls_end(); I != E; ++I) {
12416 auto *FD = dyn_cast<FunctionDecl>(I->getUnderlyingDecl());
12417 if (!FD)
12418 return nullptr;
12419
12420 if (!checkAddressOfFunctionIsAvailable(FD))
12421 continue;
12422
12423 // We have more than one result - see if it is more constrained than the
12424 // previous one.
12425 if (Result) {
12426 Optional<bool> MoreConstrainedThanPrevious = CheckMoreConstrained(FD,
12427 Result);
12428 if (!MoreConstrainedThanPrevious) {
12429 IsResultAmbiguous = true;
12430 AmbiguousDecls.push_back(FD);
12431 continue;
12432 }
12433 if (!*MoreConstrainedThanPrevious)
12434 continue;
12435 // FD is more constrained - replace Result with it.
12436 }
12437 IsResultAmbiguous = false;
12438 DAP = I.getPair();
12439 Result = FD;
12440 }
12441
12442 if (IsResultAmbiguous)
12443 return nullptr;
12444
12445 if (Result) {
12446 SmallVector<const Expr *, 1> ResultAC;
12447 // We skipped over some ambiguous declarations which might be ambiguous with
12448 // the selected result.
12449 for (FunctionDecl *Skipped : AmbiguousDecls)
12450 if (!CheckMoreConstrained(Skipped, Result).hasValue())
12451 return nullptr;
12452 Pair = DAP;
12453 }
12454 return Result;
12455 }
12456
12457 /// Given an overloaded function, tries to turn it into a non-overloaded
12458 /// function reference using resolveAddressOfSingleOverloadCandidate. This
12459 /// will perform access checks, diagnose the use of the resultant decl, and, if
12460 /// requested, potentially perform a function-to-pointer decay.
12461 ///
12462 /// Returns false if resolveAddressOfSingleOverloadCandidate fails.
12463 /// Otherwise, returns true. This may emit diagnostics and return true.
resolveAndFixAddressOfSingleOverloadCandidate(ExprResult & SrcExpr,bool DoFunctionPointerConverion)12464 bool Sema::resolveAndFixAddressOfSingleOverloadCandidate(
12465 ExprResult &SrcExpr, bool DoFunctionPointerConverion) {
12466 Expr *E = SrcExpr.get();
12467 assert(E->getType() == Context.OverloadTy && "SrcExpr must be an overload");
12468
12469 DeclAccessPair DAP;
12470 FunctionDecl *Found = resolveAddressOfSingleOverloadCandidate(E, DAP);
12471 if (!Found || Found->isCPUDispatchMultiVersion() ||
12472 Found->isCPUSpecificMultiVersion())
12473 return false;
12474
12475 // Emitting multiple diagnostics for a function that is both inaccessible and
12476 // unavailable is consistent with our behavior elsewhere. So, always check
12477 // for both.
12478 DiagnoseUseOfDecl(Found, E->getExprLoc());
12479 CheckAddressOfMemberAccess(E, DAP);
12480 Expr *Fixed = FixOverloadedFunctionReference(E, DAP, Found);
12481 if (DoFunctionPointerConverion && Fixed->getType()->isFunctionType())
12482 SrcExpr = DefaultFunctionArrayConversion(Fixed, /*Diagnose=*/false);
12483 else
12484 SrcExpr = Fixed;
12485 return true;
12486 }
12487
12488 /// Given an expression that refers to an overloaded function, try to
12489 /// resolve that overloaded function expression down to a single function.
12490 ///
12491 /// This routine can only resolve template-ids that refer to a single function
12492 /// template, where that template-id refers to a single template whose template
12493 /// arguments are either provided by the template-id or have defaults,
12494 /// as described in C++0x [temp.arg.explicit]p3.
12495 ///
12496 /// If no template-ids are found, no diagnostics are emitted and NULL is
12497 /// returned.
12498 FunctionDecl *
ResolveSingleFunctionTemplateSpecialization(OverloadExpr * ovl,bool Complain,DeclAccessPair * FoundResult)12499 Sema::ResolveSingleFunctionTemplateSpecialization(OverloadExpr *ovl,
12500 bool Complain,
12501 DeclAccessPair *FoundResult) {
12502 // C++ [over.over]p1:
12503 // [...] [Note: any redundant set of parentheses surrounding the
12504 // overloaded function name is ignored (5.1). ]
12505 // C++ [over.over]p1:
12506 // [...] The overloaded function name can be preceded by the &
12507 // operator.
12508
12509 // If we didn't actually find any template-ids, we're done.
12510 if (!ovl->hasExplicitTemplateArgs())
12511 return nullptr;
12512
12513 TemplateArgumentListInfo ExplicitTemplateArgs;
12514 ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
12515 TemplateSpecCandidateSet FailedCandidates(ovl->getNameLoc());
12516
12517 // Look through all of the overloaded functions, searching for one
12518 // whose type matches exactly.
12519 FunctionDecl *Matched = nullptr;
12520 for (UnresolvedSetIterator I = ovl->decls_begin(),
12521 E = ovl->decls_end(); I != E; ++I) {
12522 // C++0x [temp.arg.explicit]p3:
12523 // [...] In contexts where deduction is done and fails, or in contexts
12524 // where deduction is not done, if a template argument list is
12525 // specified and it, along with any default template arguments,
12526 // identifies a single function template specialization, then the
12527 // template-id is an lvalue for the function template specialization.
12528 FunctionTemplateDecl *FunctionTemplate
12529 = cast<FunctionTemplateDecl>((*I)->getUnderlyingDecl());
12530
12531 // C++ [over.over]p2:
12532 // If the name is a function template, template argument deduction is
12533 // done (14.8.2.2), and if the argument deduction succeeds, the
12534 // resulting template argument list is used to generate a single
12535 // function template specialization, which is added to the set of
12536 // overloaded functions considered.
12537 FunctionDecl *Specialization = nullptr;
12538 TemplateDeductionInfo Info(FailedCandidates.getLocation());
12539 if (TemplateDeductionResult Result
12540 = DeduceTemplateArguments(FunctionTemplate, &ExplicitTemplateArgs,
12541 Specialization, Info,
12542 /*IsAddressOfFunction*/true)) {
12543 // Make a note of the failed deduction for diagnostics.
12544 // TODO: Actually use the failed-deduction info?
12545 FailedCandidates.addCandidate()
12546 .set(I.getPair(), FunctionTemplate->getTemplatedDecl(),
12547 MakeDeductionFailureInfo(Context, Result, Info));
12548 continue;
12549 }
12550
12551 assert(Specialization && "no specialization and no error?");
12552
12553 // Multiple matches; we can't resolve to a single declaration.
12554 if (Matched) {
12555 if (Complain) {
12556 Diag(ovl->getExprLoc(), diag::err_addr_ovl_ambiguous)
12557 << ovl->getName();
12558 NoteAllOverloadCandidates(ovl);
12559 }
12560 return nullptr;
12561 }
12562
12563 Matched = Specialization;
12564 if (FoundResult) *FoundResult = I.getPair();
12565 }
12566
12567 if (Matched &&
12568 completeFunctionType(*this, Matched, ovl->getExprLoc(), Complain))
12569 return nullptr;
12570
12571 return Matched;
12572 }
12573
12574 // Resolve and fix an overloaded expression that can be resolved
12575 // because it identifies a single function template specialization.
12576 //
12577 // Last three arguments should only be supplied if Complain = true
12578 //
12579 // Return true if it was logically possible to so resolve the
12580 // expression, regardless of whether or not it succeeded. Always
12581 // returns true if 'complain' is set.
ResolveAndFixSingleFunctionTemplateSpecialization(ExprResult & SrcExpr,bool doFunctionPointerConverion,bool complain,SourceRange OpRangeForComplaining,QualType DestTypeForComplaining,unsigned DiagIDForComplaining)12582 bool Sema::ResolveAndFixSingleFunctionTemplateSpecialization(
12583 ExprResult &SrcExpr, bool doFunctionPointerConverion,
12584 bool complain, SourceRange OpRangeForComplaining,
12585 QualType DestTypeForComplaining,
12586 unsigned DiagIDForComplaining) {
12587 assert(SrcExpr.get()->getType() == Context.OverloadTy);
12588
12589 OverloadExpr::FindResult ovl = OverloadExpr::find(SrcExpr.get());
12590
12591 DeclAccessPair found;
12592 ExprResult SingleFunctionExpression;
12593 if (FunctionDecl *fn = ResolveSingleFunctionTemplateSpecialization(
12594 ovl.Expression, /*complain*/ false, &found)) {
12595 if (DiagnoseUseOfDecl(fn, SrcExpr.get()->getBeginLoc())) {
12596 SrcExpr = ExprError();
12597 return true;
12598 }
12599
12600 // It is only correct to resolve to an instance method if we're
12601 // resolving a form that's permitted to be a pointer to member.
12602 // Otherwise we'll end up making a bound member expression, which
12603 // is illegal in all the contexts we resolve like this.
12604 if (!ovl.HasFormOfMemberPointer &&
12605 isa<CXXMethodDecl>(fn) &&
12606 cast<CXXMethodDecl>(fn)->isInstance()) {
12607 if (!complain) return false;
12608
12609 Diag(ovl.Expression->getExprLoc(),
12610 diag::err_bound_member_function)
12611 << 0 << ovl.Expression->getSourceRange();
12612
12613 // TODO: I believe we only end up here if there's a mix of
12614 // static and non-static candidates (otherwise the expression
12615 // would have 'bound member' type, not 'overload' type).
12616 // Ideally we would note which candidate was chosen and why
12617 // the static candidates were rejected.
12618 SrcExpr = ExprError();
12619 return true;
12620 }
12621
12622 // Fix the expression to refer to 'fn'.
12623 SingleFunctionExpression =
12624 FixOverloadedFunctionReference(SrcExpr.get(), found, fn);
12625
12626 // If desired, do function-to-pointer decay.
12627 if (doFunctionPointerConverion) {
12628 SingleFunctionExpression =
12629 DefaultFunctionArrayLvalueConversion(SingleFunctionExpression.get());
12630 if (SingleFunctionExpression.isInvalid()) {
12631 SrcExpr = ExprError();
12632 return true;
12633 }
12634 }
12635 }
12636
12637 if (!SingleFunctionExpression.isUsable()) {
12638 if (complain) {
12639 Diag(OpRangeForComplaining.getBegin(), DiagIDForComplaining)
12640 << ovl.Expression->getName()
12641 << DestTypeForComplaining
12642 << OpRangeForComplaining
12643 << ovl.Expression->getQualifierLoc().getSourceRange();
12644 NoteAllOverloadCandidates(SrcExpr.get());
12645
12646 SrcExpr = ExprError();
12647 return true;
12648 }
12649
12650 return false;
12651 }
12652
12653 SrcExpr = SingleFunctionExpression;
12654 return true;
12655 }
12656
12657 /// Add a single candidate to the overload set.
AddOverloadedCallCandidate(Sema & S,DeclAccessPair FoundDecl,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool PartialOverloading,bool KnownValid)12658 static void AddOverloadedCallCandidate(Sema &S,
12659 DeclAccessPair FoundDecl,
12660 TemplateArgumentListInfo *ExplicitTemplateArgs,
12661 ArrayRef<Expr *> Args,
12662 OverloadCandidateSet &CandidateSet,
12663 bool PartialOverloading,
12664 bool KnownValid) {
12665 NamedDecl *Callee = FoundDecl.getDecl();
12666 if (isa<UsingShadowDecl>(Callee))
12667 Callee = cast<UsingShadowDecl>(Callee)->getTargetDecl();
12668
12669 if (FunctionDecl *Func = dyn_cast<FunctionDecl>(Callee)) {
12670 if (ExplicitTemplateArgs) {
12671 assert(!KnownValid && "Explicit template arguments?");
12672 return;
12673 }
12674 // Prevent ill-formed function decls to be added as overload candidates.
12675 if (!dyn_cast<FunctionProtoType>(Func->getType()->getAs<FunctionType>()))
12676 return;
12677
12678 S.AddOverloadCandidate(Func, FoundDecl, Args, CandidateSet,
12679 /*SuppressUserConversions=*/false,
12680 PartialOverloading);
12681 return;
12682 }
12683
12684 if (FunctionTemplateDecl *FuncTemplate
12685 = dyn_cast<FunctionTemplateDecl>(Callee)) {
12686 S.AddTemplateOverloadCandidate(FuncTemplate, FoundDecl,
12687 ExplicitTemplateArgs, Args, CandidateSet,
12688 /*SuppressUserConversions=*/false,
12689 PartialOverloading);
12690 return;
12691 }
12692
12693 assert(!KnownValid && "unhandled case in overloaded call candidate");
12694 }
12695
12696 /// Add the overload candidates named by callee and/or found by argument
12697 /// dependent lookup to the given overload set.
AddOverloadedCallCandidates(UnresolvedLookupExpr * ULE,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet,bool PartialOverloading)12698 void Sema::AddOverloadedCallCandidates(UnresolvedLookupExpr *ULE,
12699 ArrayRef<Expr *> Args,
12700 OverloadCandidateSet &CandidateSet,
12701 bool PartialOverloading) {
12702
12703 #ifndef NDEBUG
12704 // Verify that ArgumentDependentLookup is consistent with the rules
12705 // in C++0x [basic.lookup.argdep]p3:
12706 //
12707 // Let X be the lookup set produced by unqualified lookup (3.4.1)
12708 // and let Y be the lookup set produced by argument dependent
12709 // lookup (defined as follows). If X contains
12710 //
12711 // -- a declaration of a class member, or
12712 //
12713 // -- a block-scope function declaration that is not a
12714 // using-declaration, or
12715 //
12716 // -- a declaration that is neither a function or a function
12717 // template
12718 //
12719 // then Y is empty.
12720
12721 if (ULE->requiresADL()) {
12722 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
12723 E = ULE->decls_end(); I != E; ++I) {
12724 assert(!(*I)->getDeclContext()->isRecord());
12725 assert(isa<UsingShadowDecl>(*I) ||
12726 !(*I)->getDeclContext()->isFunctionOrMethod());
12727 assert((*I)->getUnderlyingDecl()->isFunctionOrFunctionTemplate());
12728 }
12729 }
12730 #endif
12731
12732 // It would be nice to avoid this copy.
12733 TemplateArgumentListInfo TABuffer;
12734 TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
12735 if (ULE->hasExplicitTemplateArgs()) {
12736 ULE->copyTemplateArgumentsInto(TABuffer);
12737 ExplicitTemplateArgs = &TABuffer;
12738 }
12739
12740 for (UnresolvedLookupExpr::decls_iterator I = ULE->decls_begin(),
12741 E = ULE->decls_end(); I != E; ++I)
12742 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
12743 CandidateSet, PartialOverloading,
12744 /*KnownValid*/ true);
12745
12746 if (ULE->requiresADL())
12747 AddArgumentDependentLookupCandidates(ULE->getName(), ULE->getExprLoc(),
12748 Args, ExplicitTemplateArgs,
12749 CandidateSet, PartialOverloading);
12750 }
12751
12752 /// Add the call candidates from the given set of lookup results to the given
12753 /// overload set. Non-function lookup results are ignored.
AddOverloadedCallCandidates(LookupResult & R,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,OverloadCandidateSet & CandidateSet)12754 void Sema::AddOverloadedCallCandidates(
12755 LookupResult &R, TemplateArgumentListInfo *ExplicitTemplateArgs,
12756 ArrayRef<Expr *> Args, OverloadCandidateSet &CandidateSet) {
12757 for (LookupResult::iterator I = R.begin(), E = R.end(); I != E; ++I)
12758 AddOverloadedCallCandidate(*this, I.getPair(), ExplicitTemplateArgs, Args,
12759 CandidateSet, false, /*KnownValid*/ false);
12760 }
12761
12762 /// Determine whether a declaration with the specified name could be moved into
12763 /// a different namespace.
canBeDeclaredInNamespace(const DeclarationName & Name)12764 static bool canBeDeclaredInNamespace(const DeclarationName &Name) {
12765 switch (Name.getCXXOverloadedOperator()) {
12766 case OO_New: case OO_Array_New:
12767 case OO_Delete: case OO_Array_Delete:
12768 return false;
12769
12770 default:
12771 return true;
12772 }
12773 }
12774
12775 /// Attempt to recover from an ill-formed use of a non-dependent name in a
12776 /// template, where the non-dependent name was declared after the template
12777 /// was defined. This is common in code written for a compilers which do not
12778 /// correctly implement two-stage name lookup.
12779 ///
12780 /// Returns true if a viable candidate was found and a diagnostic was issued.
DiagnoseTwoPhaseLookup(Sema & SemaRef,SourceLocation FnLoc,const CXXScopeSpec & SS,LookupResult & R,OverloadCandidateSet::CandidateSetKind CSK,TemplateArgumentListInfo * ExplicitTemplateArgs,ArrayRef<Expr * > Args,CXXRecordDecl ** FoundInClass=nullptr)12781 static bool DiagnoseTwoPhaseLookup(
12782 Sema &SemaRef, SourceLocation FnLoc, const CXXScopeSpec &SS,
12783 LookupResult &R, OverloadCandidateSet::CandidateSetKind CSK,
12784 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
12785 CXXRecordDecl **FoundInClass = nullptr) {
12786 if (!SemaRef.inTemplateInstantiation() || !SS.isEmpty())
12787 return false;
12788
12789 for (DeclContext *DC = SemaRef.CurContext; DC; DC = DC->getParent()) {
12790 if (DC->isTransparentContext())
12791 continue;
12792
12793 SemaRef.LookupQualifiedName(R, DC);
12794
12795 if (!R.empty()) {
12796 R.suppressDiagnostics();
12797
12798 OverloadCandidateSet Candidates(FnLoc, CSK);
12799 SemaRef.AddOverloadedCallCandidates(R, ExplicitTemplateArgs, Args,
12800 Candidates);
12801
12802 OverloadCandidateSet::iterator Best;
12803 OverloadingResult OR =
12804 Candidates.BestViableFunction(SemaRef, FnLoc, Best);
12805
12806 if (auto *RD = dyn_cast<CXXRecordDecl>(DC)) {
12807 // We either found non-function declarations or a best viable function
12808 // at class scope. A class-scope lookup result disables ADL. Don't
12809 // look past this, but let the caller know that we found something that
12810 // either is, or might be, usable in this class.
12811 if (FoundInClass) {
12812 *FoundInClass = RD;
12813 if (OR == OR_Success) {
12814 R.clear();
12815 R.addDecl(Best->FoundDecl.getDecl(), Best->FoundDecl.getAccess());
12816 R.resolveKind();
12817 }
12818 }
12819 return false;
12820 }
12821
12822 if (OR != OR_Success) {
12823 // There wasn't a unique best function or function template.
12824 return false;
12825 }
12826
12827 // Find the namespaces where ADL would have looked, and suggest
12828 // declaring the function there instead.
12829 Sema::AssociatedNamespaceSet AssociatedNamespaces;
12830 Sema::AssociatedClassSet AssociatedClasses;
12831 SemaRef.FindAssociatedClassesAndNamespaces(FnLoc, Args,
12832 AssociatedNamespaces,
12833 AssociatedClasses);
12834 Sema::AssociatedNamespaceSet SuggestedNamespaces;
12835 if (canBeDeclaredInNamespace(R.getLookupName())) {
12836 DeclContext *Std = SemaRef.getStdNamespace();
12837 for (Sema::AssociatedNamespaceSet::iterator
12838 it = AssociatedNamespaces.begin(),
12839 end = AssociatedNamespaces.end(); it != end; ++it) {
12840 // Never suggest declaring a function within namespace 'std'.
12841 if (Std && Std->Encloses(*it))
12842 continue;
12843
12844 // Never suggest declaring a function within a namespace with a
12845 // reserved name, like __gnu_cxx.
12846 NamespaceDecl *NS = dyn_cast<NamespaceDecl>(*it);
12847 if (NS &&
12848 NS->getQualifiedNameAsString().find("__") != std::string::npos)
12849 continue;
12850
12851 SuggestedNamespaces.insert(*it);
12852 }
12853 }
12854
12855 SemaRef.Diag(R.getNameLoc(), diag::err_not_found_by_two_phase_lookup)
12856 << R.getLookupName();
12857 if (SuggestedNamespaces.empty()) {
12858 SemaRef.Diag(Best->Function->getLocation(),
12859 diag::note_not_found_by_two_phase_lookup)
12860 << R.getLookupName() << 0;
12861 } else if (SuggestedNamespaces.size() == 1) {
12862 SemaRef.Diag(Best->Function->getLocation(),
12863 diag::note_not_found_by_two_phase_lookup)
12864 << R.getLookupName() << 1 << *SuggestedNamespaces.begin();
12865 } else {
12866 // FIXME: It would be useful to list the associated namespaces here,
12867 // but the diagnostics infrastructure doesn't provide a way to produce
12868 // a localized representation of a list of items.
12869 SemaRef.Diag(Best->Function->getLocation(),
12870 diag::note_not_found_by_two_phase_lookup)
12871 << R.getLookupName() << 2;
12872 }
12873
12874 // Try to recover by calling this function.
12875 return true;
12876 }
12877
12878 R.clear();
12879 }
12880
12881 return false;
12882 }
12883
12884 /// Attempt to recover from ill-formed use of a non-dependent operator in a
12885 /// template, where the non-dependent operator was declared after the template
12886 /// was defined.
12887 ///
12888 /// Returns true if a viable candidate was found and a diagnostic was issued.
12889 static bool
DiagnoseTwoPhaseOperatorLookup(Sema & SemaRef,OverloadedOperatorKind Op,SourceLocation OpLoc,ArrayRef<Expr * > Args)12890 DiagnoseTwoPhaseOperatorLookup(Sema &SemaRef, OverloadedOperatorKind Op,
12891 SourceLocation OpLoc,
12892 ArrayRef<Expr *> Args) {
12893 DeclarationName OpName =
12894 SemaRef.Context.DeclarationNames.getCXXOperatorName(Op);
12895 LookupResult R(SemaRef, OpName, OpLoc, Sema::LookupOperatorName);
12896 return DiagnoseTwoPhaseLookup(SemaRef, OpLoc, CXXScopeSpec(), R,
12897 OverloadCandidateSet::CSK_Operator,
12898 /*ExplicitTemplateArgs=*/nullptr, Args);
12899 }
12900
12901 namespace {
12902 class BuildRecoveryCallExprRAII {
12903 Sema &SemaRef;
12904 public:
BuildRecoveryCallExprRAII(Sema & S)12905 BuildRecoveryCallExprRAII(Sema &S) : SemaRef(S) {
12906 assert(SemaRef.IsBuildingRecoveryCallExpr == false);
12907 SemaRef.IsBuildingRecoveryCallExpr = true;
12908 }
12909
~BuildRecoveryCallExprRAII()12910 ~BuildRecoveryCallExprRAII() {
12911 SemaRef.IsBuildingRecoveryCallExpr = false;
12912 }
12913 };
12914
12915 }
12916
12917 /// Attempts to recover from a call where no functions were found.
12918 ///
12919 /// This function will do one of three things:
12920 /// * Diagnose, recover, and return a recovery expression.
12921 /// * Diagnose, fail to recover, and return ExprError().
12922 /// * Do not diagnose, do not recover, and return ExprResult(). The caller is
12923 /// expected to diagnose as appropriate.
12924 static ExprResult
BuildRecoveryCallExpr(Sema & SemaRef,Scope * S,Expr * Fn,UnresolvedLookupExpr * ULE,SourceLocation LParenLoc,MutableArrayRef<Expr * > Args,SourceLocation RParenLoc,bool EmptyLookup,bool AllowTypoCorrection)12925 BuildRecoveryCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
12926 UnresolvedLookupExpr *ULE,
12927 SourceLocation LParenLoc,
12928 MutableArrayRef<Expr *> Args,
12929 SourceLocation RParenLoc,
12930 bool EmptyLookup, bool AllowTypoCorrection) {
12931 // Do not try to recover if it is already building a recovery call.
12932 // This stops infinite loops for template instantiations like
12933 //
12934 // template <typename T> auto foo(T t) -> decltype(foo(t)) {}
12935 // template <typename T> auto foo(T t) -> decltype(foo(&t)) {}
12936 if (SemaRef.IsBuildingRecoveryCallExpr)
12937 return ExprResult();
12938 BuildRecoveryCallExprRAII RCE(SemaRef);
12939
12940 CXXScopeSpec SS;
12941 SS.Adopt(ULE->getQualifierLoc());
12942 SourceLocation TemplateKWLoc = ULE->getTemplateKeywordLoc();
12943
12944 TemplateArgumentListInfo TABuffer;
12945 TemplateArgumentListInfo *ExplicitTemplateArgs = nullptr;
12946 if (ULE->hasExplicitTemplateArgs()) {
12947 ULE->copyTemplateArgumentsInto(TABuffer);
12948 ExplicitTemplateArgs = &TABuffer;
12949 }
12950
12951 LookupResult R(SemaRef, ULE->getName(), ULE->getNameLoc(),
12952 Sema::LookupOrdinaryName);
12953 CXXRecordDecl *FoundInClass = nullptr;
12954 if (DiagnoseTwoPhaseLookup(SemaRef, Fn->getExprLoc(), SS, R,
12955 OverloadCandidateSet::CSK_Normal,
12956 ExplicitTemplateArgs, Args, &FoundInClass)) {
12957 // OK, diagnosed a two-phase lookup issue.
12958 } else if (EmptyLookup) {
12959 // Try to recover from an empty lookup with typo correction.
12960 R.clear();
12961 NoTypoCorrectionCCC NoTypoValidator{};
12962 FunctionCallFilterCCC FunctionCallValidator(SemaRef, Args.size(),
12963 ExplicitTemplateArgs != nullptr,
12964 dyn_cast<MemberExpr>(Fn));
12965 CorrectionCandidateCallback &Validator =
12966 AllowTypoCorrection
12967 ? static_cast<CorrectionCandidateCallback &>(FunctionCallValidator)
12968 : static_cast<CorrectionCandidateCallback &>(NoTypoValidator);
12969 if (SemaRef.DiagnoseEmptyLookup(S, SS, R, Validator, ExplicitTemplateArgs,
12970 Args))
12971 return ExprError();
12972 } else if (FoundInClass && SemaRef.getLangOpts().MSVCCompat) {
12973 // We found a usable declaration of the name in a dependent base of some
12974 // enclosing class.
12975 // FIXME: We should also explain why the candidates found by name lookup
12976 // were not viable.
12977 if (SemaRef.DiagnoseDependentMemberLookup(R))
12978 return ExprError();
12979 } else {
12980 // We had viable candidates and couldn't recover; let the caller diagnose
12981 // this.
12982 return ExprResult();
12983 }
12984
12985 // If we get here, we should have issued a diagnostic and formed a recovery
12986 // lookup result.
12987 assert(!R.empty() && "lookup results empty despite recovery");
12988
12989 // If recovery created an ambiguity, just bail out.
12990 if (R.isAmbiguous()) {
12991 R.suppressDiagnostics();
12992 return ExprError();
12993 }
12994
12995 // Build an implicit member call if appropriate. Just drop the
12996 // casts and such from the call, we don't really care.
12997 ExprResult NewFn = ExprError();
12998 if ((*R.begin())->isCXXClassMember())
12999 NewFn = SemaRef.BuildPossibleImplicitMemberExpr(SS, TemplateKWLoc, R,
13000 ExplicitTemplateArgs, S);
13001 else if (ExplicitTemplateArgs || TemplateKWLoc.isValid())
13002 NewFn = SemaRef.BuildTemplateIdExpr(SS, TemplateKWLoc, R, false,
13003 ExplicitTemplateArgs);
13004 else
13005 NewFn = SemaRef.BuildDeclarationNameExpr(SS, R, false);
13006
13007 if (NewFn.isInvalid())
13008 return ExprError();
13009
13010 // This shouldn't cause an infinite loop because we're giving it
13011 // an expression with viable lookup results, which should never
13012 // end up here.
13013 return SemaRef.BuildCallExpr(/*Scope*/ nullptr, NewFn.get(), LParenLoc,
13014 MultiExprArg(Args.data(), Args.size()),
13015 RParenLoc);
13016 }
13017
13018 /// Constructs and populates an OverloadedCandidateSet from
13019 /// the given function.
13020 /// \returns true when an the ExprResult output parameter has been set.
buildOverloadedCallSet(Scope * S,Expr * Fn,UnresolvedLookupExpr * ULE,MultiExprArg Args,SourceLocation RParenLoc,OverloadCandidateSet * CandidateSet,ExprResult * Result)13021 bool Sema::buildOverloadedCallSet(Scope *S, Expr *Fn,
13022 UnresolvedLookupExpr *ULE,
13023 MultiExprArg Args,
13024 SourceLocation RParenLoc,
13025 OverloadCandidateSet *CandidateSet,
13026 ExprResult *Result) {
13027 #ifndef NDEBUG
13028 if (ULE->requiresADL()) {
13029 // To do ADL, we must have found an unqualified name.
13030 assert(!ULE->getQualifier() && "qualified name with ADL");
13031
13032 // We don't perform ADL for implicit declarations of builtins.
13033 // Verify that this was correctly set up.
13034 FunctionDecl *F;
13035 if (ULE->decls_begin() != ULE->decls_end() &&
13036 ULE->decls_begin() + 1 == ULE->decls_end() &&
13037 (F = dyn_cast<FunctionDecl>(*ULE->decls_begin())) &&
13038 F->getBuiltinID() && F->isImplicit())
13039 llvm_unreachable("performing ADL for builtin");
13040
13041 // We don't perform ADL in C.
13042 assert(getLangOpts().CPlusPlus && "ADL enabled in C");
13043 }
13044 #endif
13045
13046 UnbridgedCastsSet UnbridgedCasts;
13047 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts)) {
13048 *Result = ExprError();
13049 return true;
13050 }
13051
13052 // Add the functions denoted by the callee to the set of candidate
13053 // functions, including those from argument-dependent lookup.
13054 AddOverloadedCallCandidates(ULE, Args, *CandidateSet);
13055
13056 if (getLangOpts().MSVCCompat &&
13057 CurContext->isDependentContext() && !isSFINAEContext() &&
13058 (isa<FunctionDecl>(CurContext) || isa<CXXRecordDecl>(CurContext))) {
13059
13060 OverloadCandidateSet::iterator Best;
13061 if (CandidateSet->empty() ||
13062 CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best) ==
13063 OR_No_Viable_Function) {
13064 // In Microsoft mode, if we are inside a template class member function
13065 // then create a type dependent CallExpr. The goal is to postpone name
13066 // lookup to instantiation time to be able to search into type dependent
13067 // base classes.
13068 CallExpr *CE =
13069 CallExpr::Create(Context, Fn, Args, Context.DependentTy, VK_PRValue,
13070 RParenLoc, CurFPFeatureOverrides());
13071 CE->markDependentForPostponedNameLookup();
13072 *Result = CE;
13073 return true;
13074 }
13075 }
13076
13077 if (CandidateSet->empty())
13078 return false;
13079
13080 UnbridgedCasts.restore();
13081 return false;
13082 }
13083
13084 // Guess at what the return type for an unresolvable overload should be.
chooseRecoveryType(OverloadCandidateSet & CS,OverloadCandidateSet::iterator * Best)13085 static QualType chooseRecoveryType(OverloadCandidateSet &CS,
13086 OverloadCandidateSet::iterator *Best) {
13087 llvm::Optional<QualType> Result;
13088 // Adjust Type after seeing a candidate.
13089 auto ConsiderCandidate = [&](const OverloadCandidate &Candidate) {
13090 if (!Candidate.Function)
13091 return;
13092 if (Candidate.Function->isInvalidDecl())
13093 return;
13094 QualType T = Candidate.Function->getReturnType();
13095 if (T.isNull())
13096 return;
13097 if (!Result)
13098 Result = T;
13099 else if (Result != T)
13100 Result = QualType();
13101 };
13102
13103 // Look for an unambiguous type from a progressively larger subset.
13104 // e.g. if types disagree, but all *viable* overloads return int, choose int.
13105 //
13106 // First, consider only the best candidate.
13107 if (Best && *Best != CS.end())
13108 ConsiderCandidate(**Best);
13109 // Next, consider only viable candidates.
13110 if (!Result)
13111 for (const auto &C : CS)
13112 if (C.Viable)
13113 ConsiderCandidate(C);
13114 // Finally, consider all candidates.
13115 if (!Result)
13116 for (const auto &C : CS)
13117 ConsiderCandidate(C);
13118
13119 if (!Result)
13120 return QualType();
13121 auto Value = Result.getValue();
13122 if (Value.isNull() || Value->isUndeducedType())
13123 return QualType();
13124 return Value;
13125 }
13126
13127 /// FinishOverloadedCallExpr - given an OverloadCandidateSet, builds and returns
13128 /// the completed call expression. If overload resolution fails, emits
13129 /// diagnostics and returns ExprError()
FinishOverloadedCallExpr(Sema & SemaRef,Scope * S,Expr * Fn,UnresolvedLookupExpr * ULE,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc,Expr * ExecConfig,OverloadCandidateSet * CandidateSet,OverloadCandidateSet::iterator * Best,OverloadingResult OverloadResult,bool AllowTypoCorrection)13130 static ExprResult FinishOverloadedCallExpr(Sema &SemaRef, Scope *S, Expr *Fn,
13131 UnresolvedLookupExpr *ULE,
13132 SourceLocation LParenLoc,
13133 MultiExprArg Args,
13134 SourceLocation RParenLoc,
13135 Expr *ExecConfig,
13136 OverloadCandidateSet *CandidateSet,
13137 OverloadCandidateSet::iterator *Best,
13138 OverloadingResult OverloadResult,
13139 bool AllowTypoCorrection) {
13140 switch (OverloadResult) {
13141 case OR_Success: {
13142 FunctionDecl *FDecl = (*Best)->Function;
13143 SemaRef.CheckUnresolvedLookupAccess(ULE, (*Best)->FoundDecl);
13144 if (SemaRef.DiagnoseUseOfDecl(FDecl, ULE->getNameLoc()))
13145 return ExprError();
13146 Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
13147 return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
13148 ExecConfig, /*IsExecConfig=*/false,
13149 (*Best)->IsADLCandidate);
13150 }
13151
13152 case OR_No_Viable_Function: {
13153 // Try to recover by looking for viable functions which the user might
13154 // have meant to call.
13155 ExprResult Recovery = BuildRecoveryCallExpr(SemaRef, S, Fn, ULE, LParenLoc,
13156 Args, RParenLoc,
13157 CandidateSet->empty(),
13158 AllowTypoCorrection);
13159 if (Recovery.isInvalid() || Recovery.isUsable())
13160 return Recovery;
13161
13162 // If the user passes in a function that we can't take the address of, we
13163 // generally end up emitting really bad error messages. Here, we attempt to
13164 // emit better ones.
13165 for (const Expr *Arg : Args) {
13166 if (!Arg->getType()->isFunctionType())
13167 continue;
13168 if (auto *DRE = dyn_cast<DeclRefExpr>(Arg->IgnoreParenImpCasts())) {
13169 auto *FD = dyn_cast<FunctionDecl>(DRE->getDecl());
13170 if (FD &&
13171 !SemaRef.checkAddressOfFunctionIsAvailable(FD, /*Complain=*/true,
13172 Arg->getExprLoc()))
13173 return ExprError();
13174 }
13175 }
13176
13177 CandidateSet->NoteCandidates(
13178 PartialDiagnosticAt(
13179 Fn->getBeginLoc(),
13180 SemaRef.PDiag(diag::err_ovl_no_viable_function_in_call)
13181 << ULE->getName() << Fn->getSourceRange()),
13182 SemaRef, OCD_AllCandidates, Args);
13183 break;
13184 }
13185
13186 case OR_Ambiguous:
13187 CandidateSet->NoteCandidates(
13188 PartialDiagnosticAt(Fn->getBeginLoc(),
13189 SemaRef.PDiag(diag::err_ovl_ambiguous_call)
13190 << ULE->getName() << Fn->getSourceRange()),
13191 SemaRef, OCD_AmbiguousCandidates, Args);
13192 break;
13193
13194 case OR_Deleted: {
13195 CandidateSet->NoteCandidates(
13196 PartialDiagnosticAt(Fn->getBeginLoc(),
13197 SemaRef.PDiag(diag::err_ovl_deleted_call)
13198 << ULE->getName() << Fn->getSourceRange()),
13199 SemaRef, OCD_AllCandidates, Args);
13200
13201 // We emitted an error for the unavailable/deleted function call but keep
13202 // the call in the AST.
13203 FunctionDecl *FDecl = (*Best)->Function;
13204 Fn = SemaRef.FixOverloadedFunctionReference(Fn, (*Best)->FoundDecl, FDecl);
13205 return SemaRef.BuildResolvedCallExpr(Fn, FDecl, LParenLoc, Args, RParenLoc,
13206 ExecConfig, /*IsExecConfig=*/false,
13207 (*Best)->IsADLCandidate);
13208 }
13209 }
13210
13211 // Overload resolution failed, try to recover.
13212 SmallVector<Expr *, 8> SubExprs = {Fn};
13213 SubExprs.append(Args.begin(), Args.end());
13214 return SemaRef.CreateRecoveryExpr(Fn->getBeginLoc(), RParenLoc, SubExprs,
13215 chooseRecoveryType(*CandidateSet, Best));
13216 }
13217
markUnaddressableCandidatesUnviable(Sema & S,OverloadCandidateSet & CS)13218 static void markUnaddressableCandidatesUnviable(Sema &S,
13219 OverloadCandidateSet &CS) {
13220 for (auto I = CS.begin(), E = CS.end(); I != E; ++I) {
13221 if (I->Viable &&
13222 !S.checkAddressOfFunctionIsAvailable(I->Function, /*Complain=*/false)) {
13223 I->Viable = false;
13224 I->FailureKind = ovl_fail_addr_not_available;
13225 }
13226 }
13227 }
13228
13229 /// BuildOverloadedCallExpr - Given the call expression that calls Fn
13230 /// (which eventually refers to the declaration Func) and the call
13231 /// arguments Args/NumArgs, attempt to resolve the function call down
13232 /// to a specific function. If overload resolution succeeds, returns
13233 /// the call expression produced by overload resolution.
13234 /// Otherwise, emits diagnostics and returns ExprError.
BuildOverloadedCallExpr(Scope * S,Expr * Fn,UnresolvedLookupExpr * ULE,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc,Expr * ExecConfig,bool AllowTypoCorrection,bool CalleesAddressIsTaken)13235 ExprResult Sema::BuildOverloadedCallExpr(Scope *S, Expr *Fn,
13236 UnresolvedLookupExpr *ULE,
13237 SourceLocation LParenLoc,
13238 MultiExprArg Args,
13239 SourceLocation RParenLoc,
13240 Expr *ExecConfig,
13241 bool AllowTypoCorrection,
13242 bool CalleesAddressIsTaken) {
13243 OverloadCandidateSet CandidateSet(Fn->getExprLoc(),
13244 OverloadCandidateSet::CSK_Normal);
13245 ExprResult result;
13246
13247 if (buildOverloadedCallSet(S, Fn, ULE, Args, LParenLoc, &CandidateSet,
13248 &result))
13249 return result;
13250
13251 // If the user handed us something like `(&Foo)(Bar)`, we need to ensure that
13252 // functions that aren't addressible are considered unviable.
13253 if (CalleesAddressIsTaken)
13254 markUnaddressableCandidatesUnviable(*this, CandidateSet);
13255
13256 OverloadCandidateSet::iterator Best;
13257 OverloadingResult OverloadResult =
13258 CandidateSet.BestViableFunction(*this, Fn->getBeginLoc(), Best);
13259
13260 return FinishOverloadedCallExpr(*this, S, Fn, ULE, LParenLoc, Args, RParenLoc,
13261 ExecConfig, &CandidateSet, &Best,
13262 OverloadResult, AllowTypoCorrection);
13263 }
13264
IsOverloaded(const UnresolvedSetImpl & Functions)13265 static bool IsOverloaded(const UnresolvedSetImpl &Functions) {
13266 return Functions.size() > 1 ||
13267 (Functions.size() == 1 &&
13268 isa<FunctionTemplateDecl>((*Functions.begin())->getUnderlyingDecl()));
13269 }
13270
CreateUnresolvedLookupExpr(CXXRecordDecl * NamingClass,NestedNameSpecifierLoc NNSLoc,DeclarationNameInfo DNI,const UnresolvedSetImpl & Fns,bool PerformADL)13271 ExprResult Sema::CreateUnresolvedLookupExpr(CXXRecordDecl *NamingClass,
13272 NestedNameSpecifierLoc NNSLoc,
13273 DeclarationNameInfo DNI,
13274 const UnresolvedSetImpl &Fns,
13275 bool PerformADL) {
13276 return UnresolvedLookupExpr::Create(Context, NamingClass, NNSLoc, DNI,
13277 PerformADL, IsOverloaded(Fns),
13278 Fns.begin(), Fns.end());
13279 }
13280
13281 /// Create a unary operation that may resolve to an overloaded
13282 /// operator.
13283 ///
13284 /// \param OpLoc The location of the operator itself (e.g., '*').
13285 ///
13286 /// \param Opc The UnaryOperatorKind that describes this operator.
13287 ///
13288 /// \param Fns The set of non-member functions that will be
13289 /// considered by overload resolution. The caller needs to build this
13290 /// set based on the context using, e.g.,
13291 /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13292 /// set should not contain any member functions; those will be added
13293 /// by CreateOverloadedUnaryOp().
13294 ///
13295 /// \param Input The input argument.
13296 ExprResult
CreateOverloadedUnaryOp(SourceLocation OpLoc,UnaryOperatorKind Opc,const UnresolvedSetImpl & Fns,Expr * Input,bool PerformADL)13297 Sema::CreateOverloadedUnaryOp(SourceLocation OpLoc, UnaryOperatorKind Opc,
13298 const UnresolvedSetImpl &Fns,
13299 Expr *Input, bool PerformADL) {
13300 OverloadedOperatorKind Op = UnaryOperator::getOverloadedOperator(Opc);
13301 assert(Op != OO_None && "Invalid opcode for overloaded unary operator");
13302 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13303 // TODO: provide better source location info.
13304 DeclarationNameInfo OpNameInfo(OpName, OpLoc);
13305
13306 if (checkPlaceholderForOverload(*this, Input))
13307 return ExprError();
13308
13309 Expr *Args[2] = { Input, nullptr };
13310 unsigned NumArgs = 1;
13311
13312 // For post-increment and post-decrement, add the implicit '0' as
13313 // the second argument, so that we know this is a post-increment or
13314 // post-decrement.
13315 if (Opc == UO_PostInc || Opc == UO_PostDec) {
13316 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
13317 Args[1] = IntegerLiteral::Create(Context, Zero, Context.IntTy,
13318 SourceLocation());
13319 NumArgs = 2;
13320 }
13321
13322 ArrayRef<Expr *> ArgsArray(Args, NumArgs);
13323
13324 if (Input->isTypeDependent()) {
13325 if (Fns.empty())
13326 return UnaryOperator::Create(Context, Input, Opc, Context.DependentTy,
13327 VK_PRValue, OK_Ordinary, OpLoc, false,
13328 CurFPFeatureOverrides());
13329
13330 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
13331 ExprResult Fn = CreateUnresolvedLookupExpr(
13332 NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns);
13333 if (Fn.isInvalid())
13334 return ExprError();
13335 return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), ArgsArray,
13336 Context.DependentTy, VK_PRValue, OpLoc,
13337 CurFPFeatureOverrides());
13338 }
13339
13340 // Build an empty overload set.
13341 OverloadCandidateSet CandidateSet(OpLoc, OverloadCandidateSet::CSK_Operator);
13342
13343 // Add the candidates from the given function set.
13344 AddNonMemberOperatorCandidates(Fns, ArgsArray, CandidateSet);
13345
13346 // Add operator candidates that are member functions.
13347 AddMemberOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
13348
13349 // Add candidates from ADL.
13350 if (PerformADL) {
13351 AddArgumentDependentLookupCandidates(OpName, OpLoc, ArgsArray,
13352 /*ExplicitTemplateArgs*/nullptr,
13353 CandidateSet);
13354 }
13355
13356 // Add builtin operator candidates.
13357 AddBuiltinOperatorCandidates(Op, OpLoc, ArgsArray, CandidateSet);
13358
13359 bool HadMultipleCandidates = (CandidateSet.size() > 1);
13360
13361 // Perform overload resolution.
13362 OverloadCandidateSet::iterator Best;
13363 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
13364 case OR_Success: {
13365 // We found a built-in operator or an overloaded operator.
13366 FunctionDecl *FnDecl = Best->Function;
13367
13368 if (FnDecl) {
13369 Expr *Base = nullptr;
13370 // We matched an overloaded operator. Build a call to that
13371 // operator.
13372
13373 // Convert the arguments.
13374 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
13375 CheckMemberOperatorAccess(OpLoc, Args[0], nullptr, Best->FoundDecl);
13376
13377 ExprResult InputRes =
13378 PerformObjectArgumentInitialization(Input, /*Qualifier=*/nullptr,
13379 Best->FoundDecl, Method);
13380 if (InputRes.isInvalid())
13381 return ExprError();
13382 Base = Input = InputRes.get();
13383 } else {
13384 // Convert the arguments.
13385 ExprResult InputInit
13386 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
13387 Context,
13388 FnDecl->getParamDecl(0)),
13389 SourceLocation(),
13390 Input);
13391 if (InputInit.isInvalid())
13392 return ExprError();
13393 Input = InputInit.get();
13394 }
13395
13396 // Build the actual expression node.
13397 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl, Best->FoundDecl,
13398 Base, HadMultipleCandidates,
13399 OpLoc);
13400 if (FnExpr.isInvalid())
13401 return ExprError();
13402
13403 // Determine the result type.
13404 QualType ResultTy = FnDecl->getReturnType();
13405 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
13406 ResultTy = ResultTy.getNonLValueExprType(Context);
13407
13408 Args[0] = Input;
13409 CallExpr *TheCall = CXXOperatorCallExpr::Create(
13410 Context, Op, FnExpr.get(), ArgsArray, ResultTy, VK, OpLoc,
13411 CurFPFeatureOverrides(), Best->IsADLCandidate);
13412
13413 if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall, FnDecl))
13414 return ExprError();
13415
13416 if (CheckFunctionCall(FnDecl, TheCall,
13417 FnDecl->getType()->castAs<FunctionProtoType>()))
13418 return ExprError();
13419 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), FnDecl);
13420 } else {
13421 // We matched a built-in operator. Convert the arguments, then
13422 // break out so that we will build the appropriate built-in
13423 // operator node.
13424 ExprResult InputRes = PerformImplicitConversion(
13425 Input, Best->BuiltinParamTypes[0], Best->Conversions[0], AA_Passing,
13426 CCK_ForBuiltinOverloadedOp);
13427 if (InputRes.isInvalid())
13428 return ExprError();
13429 Input = InputRes.get();
13430 break;
13431 }
13432 }
13433
13434 case OR_No_Viable_Function:
13435 // This is an erroneous use of an operator which can be overloaded by
13436 // a non-member function. Check for non-member operators which were
13437 // defined too late to be candidates.
13438 if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, ArgsArray))
13439 // FIXME: Recover by calling the found function.
13440 return ExprError();
13441
13442 // No viable function; fall through to handling this as a
13443 // built-in operator, which will produce an error message for us.
13444 break;
13445
13446 case OR_Ambiguous:
13447 CandidateSet.NoteCandidates(
13448 PartialDiagnosticAt(OpLoc,
13449 PDiag(diag::err_ovl_ambiguous_oper_unary)
13450 << UnaryOperator::getOpcodeStr(Opc)
13451 << Input->getType() << Input->getSourceRange()),
13452 *this, OCD_AmbiguousCandidates, ArgsArray,
13453 UnaryOperator::getOpcodeStr(Opc), OpLoc);
13454 return ExprError();
13455
13456 case OR_Deleted:
13457 CandidateSet.NoteCandidates(
13458 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
13459 << UnaryOperator::getOpcodeStr(Opc)
13460 << Input->getSourceRange()),
13461 *this, OCD_AllCandidates, ArgsArray, UnaryOperator::getOpcodeStr(Opc),
13462 OpLoc);
13463 return ExprError();
13464 }
13465
13466 // Either we found no viable overloaded operator or we matched a
13467 // built-in operator. In either case, fall through to trying to
13468 // build a built-in operation.
13469 return CreateBuiltinUnaryOp(OpLoc, Opc, Input);
13470 }
13471
13472 /// Perform lookup for an overloaded binary operator.
LookupOverloadedBinOp(OverloadCandidateSet & CandidateSet,OverloadedOperatorKind Op,const UnresolvedSetImpl & Fns,ArrayRef<Expr * > Args,bool PerformADL)13473 void Sema::LookupOverloadedBinOp(OverloadCandidateSet &CandidateSet,
13474 OverloadedOperatorKind Op,
13475 const UnresolvedSetImpl &Fns,
13476 ArrayRef<Expr *> Args, bool PerformADL) {
13477 SourceLocation OpLoc = CandidateSet.getLocation();
13478
13479 OverloadedOperatorKind ExtraOp =
13480 CandidateSet.getRewriteInfo().AllowRewrittenCandidates
13481 ? getRewrittenOverloadedOperator(Op)
13482 : OO_None;
13483
13484 // Add the candidates from the given function set. This also adds the
13485 // rewritten candidates using these functions if necessary.
13486 AddNonMemberOperatorCandidates(Fns, Args, CandidateSet);
13487
13488 // Add operator candidates that are member functions.
13489 AddMemberOperatorCandidates(Op, OpLoc, Args, CandidateSet);
13490 if (CandidateSet.getRewriteInfo().shouldAddReversed(Op))
13491 AddMemberOperatorCandidates(Op, OpLoc, {Args[1], Args[0]}, CandidateSet,
13492 OverloadCandidateParamOrder::Reversed);
13493
13494 // In C++20, also add any rewritten member candidates.
13495 if (ExtraOp) {
13496 AddMemberOperatorCandidates(ExtraOp, OpLoc, Args, CandidateSet);
13497 if (CandidateSet.getRewriteInfo().shouldAddReversed(ExtraOp))
13498 AddMemberOperatorCandidates(ExtraOp, OpLoc, {Args[1], Args[0]},
13499 CandidateSet,
13500 OverloadCandidateParamOrder::Reversed);
13501 }
13502
13503 // Add candidates from ADL. Per [over.match.oper]p2, this lookup is not
13504 // performed for an assignment operator (nor for operator[] nor operator->,
13505 // which don't get here).
13506 if (Op != OO_Equal && PerformADL) {
13507 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13508 AddArgumentDependentLookupCandidates(OpName, OpLoc, Args,
13509 /*ExplicitTemplateArgs*/ nullptr,
13510 CandidateSet);
13511 if (ExtraOp) {
13512 DeclarationName ExtraOpName =
13513 Context.DeclarationNames.getCXXOperatorName(ExtraOp);
13514 AddArgumentDependentLookupCandidates(ExtraOpName, OpLoc, Args,
13515 /*ExplicitTemplateArgs*/ nullptr,
13516 CandidateSet);
13517 }
13518 }
13519
13520 // Add builtin operator candidates.
13521 //
13522 // FIXME: We don't add any rewritten candidates here. This is strictly
13523 // incorrect; a builtin candidate could be hidden by a non-viable candidate,
13524 // resulting in our selecting a rewritten builtin candidate. For example:
13525 //
13526 // enum class E { e };
13527 // bool operator!=(E, E) requires false;
13528 // bool k = E::e != E::e;
13529 //
13530 // ... should select the rewritten builtin candidate 'operator==(E, E)'. But
13531 // it seems unreasonable to consider rewritten builtin candidates. A core
13532 // issue has been filed proposing to removed this requirement.
13533 AddBuiltinOperatorCandidates(Op, OpLoc, Args, CandidateSet);
13534 }
13535
13536 /// Create a binary operation that may resolve to an overloaded
13537 /// operator.
13538 ///
13539 /// \param OpLoc The location of the operator itself (e.g., '+').
13540 ///
13541 /// \param Opc The BinaryOperatorKind that describes this operator.
13542 ///
13543 /// \param Fns The set of non-member functions that will be
13544 /// considered by overload resolution. The caller needs to build this
13545 /// set based on the context using, e.g.,
13546 /// LookupOverloadedOperatorName() and ArgumentDependentLookup(). This
13547 /// set should not contain any member functions; those will be added
13548 /// by CreateOverloadedBinOp().
13549 ///
13550 /// \param LHS Left-hand argument.
13551 /// \param RHS Right-hand argument.
13552 /// \param PerformADL Whether to consider operator candidates found by ADL.
13553 /// \param AllowRewrittenCandidates Whether to consider candidates found by
13554 /// C++20 operator rewrites.
13555 /// \param DefaultedFn If we are synthesizing a defaulted operator function,
13556 /// the function in question. Such a function is never a candidate in
13557 /// our overload resolution. This also enables synthesizing a three-way
13558 /// comparison from < and == as described in C++20 [class.spaceship]p1.
CreateOverloadedBinOp(SourceLocation OpLoc,BinaryOperatorKind Opc,const UnresolvedSetImpl & Fns,Expr * LHS,Expr * RHS,bool PerformADL,bool AllowRewrittenCandidates,FunctionDecl * DefaultedFn)13559 ExprResult Sema::CreateOverloadedBinOp(SourceLocation OpLoc,
13560 BinaryOperatorKind Opc,
13561 const UnresolvedSetImpl &Fns, Expr *LHS,
13562 Expr *RHS, bool PerformADL,
13563 bool AllowRewrittenCandidates,
13564 FunctionDecl *DefaultedFn) {
13565 Expr *Args[2] = { LHS, RHS };
13566 LHS=RHS=nullptr; // Please use only Args instead of LHS/RHS couple
13567
13568 if (!getLangOpts().CPlusPlus20)
13569 AllowRewrittenCandidates = false;
13570
13571 OverloadedOperatorKind Op = BinaryOperator::getOverloadedOperator(Opc);
13572
13573 // If either side is type-dependent, create an appropriate dependent
13574 // expression.
13575 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
13576 if (Fns.empty()) {
13577 // If there are no functions to store, just build a dependent
13578 // BinaryOperator or CompoundAssignment.
13579 if (BinaryOperator::isCompoundAssignmentOp(Opc))
13580 return CompoundAssignOperator::Create(
13581 Context, Args[0], Args[1], Opc, Context.DependentTy, VK_LValue,
13582 OK_Ordinary, OpLoc, CurFPFeatureOverrides(), Context.DependentTy,
13583 Context.DependentTy);
13584 return BinaryOperator::Create(
13585 Context, Args[0], Args[1], Opc, Context.DependentTy, VK_PRValue,
13586 OK_Ordinary, OpLoc, CurFPFeatureOverrides());
13587 }
13588
13589 // FIXME: save results of ADL from here?
13590 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
13591 // TODO: provide better source location info in DNLoc component.
13592 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(Op);
13593 DeclarationNameInfo OpNameInfo(OpName, OpLoc);
13594 ExprResult Fn = CreateUnresolvedLookupExpr(
13595 NamingClass, NestedNameSpecifierLoc(), OpNameInfo, Fns, PerformADL);
13596 if (Fn.isInvalid())
13597 return ExprError();
13598 return CXXOperatorCallExpr::Create(Context, Op, Fn.get(), Args,
13599 Context.DependentTy, VK_PRValue, OpLoc,
13600 CurFPFeatureOverrides());
13601 }
13602
13603 // Always do placeholder-like conversions on the RHS.
13604 if (checkPlaceholderForOverload(*this, Args[1]))
13605 return ExprError();
13606
13607 // Do placeholder-like conversion on the LHS; note that we should
13608 // not get here with a PseudoObject LHS.
13609 assert(Args[0]->getObjectKind() != OK_ObjCProperty);
13610 if (checkPlaceholderForOverload(*this, Args[0]))
13611 return ExprError();
13612
13613 // If this is the assignment operator, we only perform overload resolution
13614 // if the left-hand side is a class or enumeration type. This is actually
13615 // a hack. The standard requires that we do overload resolution between the
13616 // various built-in candidates, but as DR507 points out, this can lead to
13617 // problems. So we do it this way, which pretty much follows what GCC does.
13618 // Note that we go the traditional code path for compound assignment forms.
13619 if (Opc == BO_Assign && !Args[0]->getType()->isOverloadableType())
13620 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13621
13622 // If this is the .* operator, which is not overloadable, just
13623 // create a built-in binary operator.
13624 if (Opc == BO_PtrMemD)
13625 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13626
13627 // Build the overload set.
13628 OverloadCandidateSet CandidateSet(
13629 OpLoc, OverloadCandidateSet::CSK_Operator,
13630 OverloadCandidateSet::OperatorRewriteInfo(Op, AllowRewrittenCandidates));
13631 if (DefaultedFn)
13632 CandidateSet.exclude(DefaultedFn);
13633 LookupOverloadedBinOp(CandidateSet, Op, Fns, Args, PerformADL);
13634
13635 bool HadMultipleCandidates = (CandidateSet.size() > 1);
13636
13637 // Perform overload resolution.
13638 OverloadCandidateSet::iterator Best;
13639 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
13640 case OR_Success: {
13641 // We found a built-in operator or an overloaded operator.
13642 FunctionDecl *FnDecl = Best->Function;
13643
13644 bool IsReversed = Best->isReversed();
13645 if (IsReversed)
13646 std::swap(Args[0], Args[1]);
13647
13648 if (FnDecl) {
13649 Expr *Base = nullptr;
13650 // We matched an overloaded operator. Build a call to that
13651 // operator.
13652
13653 OverloadedOperatorKind ChosenOp =
13654 FnDecl->getDeclName().getCXXOverloadedOperator();
13655
13656 // C++2a [over.match.oper]p9:
13657 // If a rewritten operator== candidate is selected by overload
13658 // resolution for an operator@, its return type shall be cv bool
13659 if (Best->RewriteKind && ChosenOp == OO_EqualEqual &&
13660 !FnDecl->getReturnType()->isBooleanType()) {
13661 bool IsExtension =
13662 FnDecl->getReturnType()->isIntegralOrUnscopedEnumerationType();
13663 Diag(OpLoc, IsExtension ? diag::ext_ovl_rewrite_equalequal_not_bool
13664 : diag::err_ovl_rewrite_equalequal_not_bool)
13665 << FnDecl->getReturnType() << BinaryOperator::getOpcodeStr(Opc)
13666 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13667 Diag(FnDecl->getLocation(), diag::note_declared_at);
13668 if (!IsExtension)
13669 return ExprError();
13670 }
13671
13672 if (AllowRewrittenCandidates && !IsReversed &&
13673 CandidateSet.getRewriteInfo().isReversible()) {
13674 // We could have reversed this operator, but didn't. Check if some
13675 // reversed form was a viable candidate, and if so, if it had a
13676 // better conversion for either parameter. If so, this call is
13677 // formally ambiguous, and allowing it is an extension.
13678 llvm::SmallVector<FunctionDecl*, 4> AmbiguousWith;
13679 for (OverloadCandidate &Cand : CandidateSet) {
13680 if (Cand.Viable && Cand.Function && Cand.isReversed() &&
13681 haveSameParameterTypes(Context, Cand.Function, FnDecl, 2)) {
13682 for (unsigned ArgIdx = 0; ArgIdx < 2; ++ArgIdx) {
13683 if (CompareImplicitConversionSequences(
13684 *this, OpLoc, Cand.Conversions[ArgIdx],
13685 Best->Conversions[ArgIdx]) ==
13686 ImplicitConversionSequence::Better) {
13687 AmbiguousWith.push_back(Cand.Function);
13688 break;
13689 }
13690 }
13691 }
13692 }
13693
13694 if (!AmbiguousWith.empty()) {
13695 bool AmbiguousWithSelf =
13696 AmbiguousWith.size() == 1 &&
13697 declaresSameEntity(AmbiguousWith.front(), FnDecl);
13698 Diag(OpLoc, diag::ext_ovl_ambiguous_oper_binary_reversed)
13699 << BinaryOperator::getOpcodeStr(Opc)
13700 << Args[0]->getType() << Args[1]->getType() << AmbiguousWithSelf
13701 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13702 if (AmbiguousWithSelf) {
13703 Diag(FnDecl->getLocation(),
13704 diag::note_ovl_ambiguous_oper_binary_reversed_self);
13705 } else {
13706 Diag(FnDecl->getLocation(),
13707 diag::note_ovl_ambiguous_oper_binary_selected_candidate);
13708 for (auto *F : AmbiguousWith)
13709 Diag(F->getLocation(),
13710 diag::note_ovl_ambiguous_oper_binary_reversed_candidate);
13711 }
13712 }
13713 }
13714
13715 // Convert the arguments.
13716 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(FnDecl)) {
13717 // Best->Access is only meaningful for class members.
13718 CheckMemberOperatorAccess(OpLoc, Args[0], Args[1], Best->FoundDecl);
13719
13720 ExprResult Arg1 =
13721 PerformCopyInitialization(
13722 InitializedEntity::InitializeParameter(Context,
13723 FnDecl->getParamDecl(0)),
13724 SourceLocation(), Args[1]);
13725 if (Arg1.isInvalid())
13726 return ExprError();
13727
13728 ExprResult Arg0 =
13729 PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
13730 Best->FoundDecl, Method);
13731 if (Arg0.isInvalid())
13732 return ExprError();
13733 Base = Args[0] = Arg0.getAs<Expr>();
13734 Args[1] = RHS = Arg1.getAs<Expr>();
13735 } else {
13736 // Convert the arguments.
13737 ExprResult Arg0 = PerformCopyInitialization(
13738 InitializedEntity::InitializeParameter(Context,
13739 FnDecl->getParamDecl(0)),
13740 SourceLocation(), Args[0]);
13741 if (Arg0.isInvalid())
13742 return ExprError();
13743
13744 ExprResult Arg1 =
13745 PerformCopyInitialization(
13746 InitializedEntity::InitializeParameter(Context,
13747 FnDecl->getParamDecl(1)),
13748 SourceLocation(), Args[1]);
13749 if (Arg1.isInvalid())
13750 return ExprError();
13751 Args[0] = LHS = Arg0.getAs<Expr>();
13752 Args[1] = RHS = Arg1.getAs<Expr>();
13753 }
13754
13755 // Build the actual expression node.
13756 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
13757 Best->FoundDecl, Base,
13758 HadMultipleCandidates, OpLoc);
13759 if (FnExpr.isInvalid())
13760 return ExprError();
13761
13762 // Determine the result type.
13763 QualType ResultTy = FnDecl->getReturnType();
13764 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
13765 ResultTy = ResultTy.getNonLValueExprType(Context);
13766
13767 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
13768 Context, ChosenOp, FnExpr.get(), Args, ResultTy, VK, OpLoc,
13769 CurFPFeatureOverrides(), Best->IsADLCandidate);
13770
13771 if (CheckCallReturnType(FnDecl->getReturnType(), OpLoc, TheCall,
13772 FnDecl))
13773 return ExprError();
13774
13775 ArrayRef<const Expr *> ArgsArray(Args, 2);
13776 const Expr *ImplicitThis = nullptr;
13777 // Cut off the implicit 'this'.
13778 if (isa<CXXMethodDecl>(FnDecl)) {
13779 ImplicitThis = ArgsArray[0];
13780 ArgsArray = ArgsArray.slice(1);
13781 }
13782
13783 // Check for a self move.
13784 if (Op == OO_Equal)
13785 DiagnoseSelfMove(Args[0], Args[1], OpLoc);
13786
13787 if (ImplicitThis) {
13788 QualType ThisType = Context.getPointerType(ImplicitThis->getType());
13789 QualType ThisTypeFromDecl = Context.getPointerType(
13790 cast<CXXMethodDecl>(FnDecl)->getThisObjectType());
13791
13792 CheckArgAlignment(OpLoc, FnDecl, "'this'", ThisType,
13793 ThisTypeFromDecl);
13794 }
13795
13796 checkCall(FnDecl, nullptr, ImplicitThis, ArgsArray,
13797 isa<CXXMethodDecl>(FnDecl), OpLoc, TheCall->getSourceRange(),
13798 VariadicDoesNotApply);
13799
13800 ExprResult R = MaybeBindToTemporary(TheCall);
13801 if (R.isInvalid())
13802 return ExprError();
13803
13804 R = CheckForImmediateInvocation(R, FnDecl);
13805 if (R.isInvalid())
13806 return ExprError();
13807
13808 // For a rewritten candidate, we've already reversed the arguments
13809 // if needed. Perform the rest of the rewrite now.
13810 if ((Best->RewriteKind & CRK_DifferentOperator) ||
13811 (Op == OO_Spaceship && IsReversed)) {
13812 if (Op == OO_ExclaimEqual) {
13813 assert(ChosenOp == OO_EqualEqual && "unexpected operator name");
13814 R = CreateBuiltinUnaryOp(OpLoc, UO_LNot, R.get());
13815 } else {
13816 assert(ChosenOp == OO_Spaceship && "unexpected operator name");
13817 llvm::APSInt Zero(Context.getTypeSize(Context.IntTy), false);
13818 Expr *ZeroLiteral =
13819 IntegerLiteral::Create(Context, Zero, Context.IntTy, OpLoc);
13820
13821 Sema::CodeSynthesisContext Ctx;
13822 Ctx.Kind = Sema::CodeSynthesisContext::RewritingOperatorAsSpaceship;
13823 Ctx.Entity = FnDecl;
13824 pushCodeSynthesisContext(Ctx);
13825
13826 R = CreateOverloadedBinOp(
13827 OpLoc, Opc, Fns, IsReversed ? ZeroLiteral : R.get(),
13828 IsReversed ? R.get() : ZeroLiteral, PerformADL,
13829 /*AllowRewrittenCandidates=*/false);
13830
13831 popCodeSynthesisContext();
13832 }
13833 if (R.isInvalid())
13834 return ExprError();
13835 } else {
13836 assert(ChosenOp == Op && "unexpected operator name");
13837 }
13838
13839 // Make a note in the AST if we did any rewriting.
13840 if (Best->RewriteKind != CRK_None)
13841 R = new (Context) CXXRewrittenBinaryOperator(R.get(), IsReversed);
13842
13843 return R;
13844 } else {
13845 // We matched a built-in operator. Convert the arguments, then
13846 // break out so that we will build the appropriate built-in
13847 // operator node.
13848 ExprResult ArgsRes0 = PerformImplicitConversion(
13849 Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
13850 AA_Passing, CCK_ForBuiltinOverloadedOp);
13851 if (ArgsRes0.isInvalid())
13852 return ExprError();
13853 Args[0] = ArgsRes0.get();
13854
13855 ExprResult ArgsRes1 = PerformImplicitConversion(
13856 Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
13857 AA_Passing, CCK_ForBuiltinOverloadedOp);
13858 if (ArgsRes1.isInvalid())
13859 return ExprError();
13860 Args[1] = ArgsRes1.get();
13861 break;
13862 }
13863 }
13864
13865 case OR_No_Viable_Function: {
13866 // C++ [over.match.oper]p9:
13867 // If the operator is the operator , [...] and there are no
13868 // viable functions, then the operator is assumed to be the
13869 // built-in operator and interpreted according to clause 5.
13870 if (Opc == BO_Comma)
13871 break;
13872
13873 // When defaulting an 'operator<=>', we can try to synthesize a three-way
13874 // compare result using '==' and '<'.
13875 if (DefaultedFn && Opc == BO_Cmp) {
13876 ExprResult E = BuildSynthesizedThreeWayComparison(OpLoc, Fns, Args[0],
13877 Args[1], DefaultedFn);
13878 if (E.isInvalid() || E.isUsable())
13879 return E;
13880 }
13881
13882 // For class as left operand for assignment or compound assignment
13883 // operator do not fall through to handling in built-in, but report that
13884 // no overloaded assignment operator found
13885 ExprResult Result = ExprError();
13886 StringRef OpcStr = BinaryOperator::getOpcodeStr(Opc);
13887 auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates,
13888 Args, OpLoc);
13889 DeferDiagsRAII DDR(*this,
13890 CandidateSet.shouldDeferDiags(*this, Args, OpLoc));
13891 if (Args[0]->getType()->isRecordType() &&
13892 Opc >= BO_Assign && Opc <= BO_OrAssign) {
13893 Diag(OpLoc, diag::err_ovl_no_viable_oper)
13894 << BinaryOperator::getOpcodeStr(Opc)
13895 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13896 if (Args[0]->getType()->isIncompleteType()) {
13897 Diag(OpLoc, diag::note_assign_lhs_incomplete)
13898 << Args[0]->getType()
13899 << Args[0]->getSourceRange() << Args[1]->getSourceRange();
13900 }
13901 } else {
13902 // This is an erroneous use of an operator which can be overloaded by
13903 // a non-member function. Check for non-member operators which were
13904 // defined too late to be candidates.
13905 if (DiagnoseTwoPhaseOperatorLookup(*this, Op, OpLoc, Args))
13906 // FIXME: Recover by calling the found function.
13907 return ExprError();
13908
13909 // No viable function; try to create a built-in operation, which will
13910 // produce an error. Then, show the non-viable candidates.
13911 Result = CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13912 }
13913 assert(Result.isInvalid() &&
13914 "C++ binary operator overloading is missing candidates!");
13915 CandidateSet.NoteCandidates(*this, Args, Cands, OpcStr, OpLoc);
13916 return Result;
13917 }
13918
13919 case OR_Ambiguous:
13920 CandidateSet.NoteCandidates(
13921 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
13922 << BinaryOperator::getOpcodeStr(Opc)
13923 << Args[0]->getType()
13924 << Args[1]->getType()
13925 << Args[0]->getSourceRange()
13926 << Args[1]->getSourceRange()),
13927 *this, OCD_AmbiguousCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
13928 OpLoc);
13929 return ExprError();
13930
13931 case OR_Deleted:
13932 if (isImplicitlyDeleted(Best->Function)) {
13933 FunctionDecl *DeletedFD = Best->Function;
13934 DefaultedFunctionKind DFK = getDefaultedFunctionKind(DeletedFD);
13935 if (DFK.isSpecialMember()) {
13936 Diag(OpLoc, diag::err_ovl_deleted_special_oper)
13937 << Args[0]->getType() << DFK.asSpecialMember();
13938 } else {
13939 assert(DFK.isComparison());
13940 Diag(OpLoc, diag::err_ovl_deleted_comparison)
13941 << Args[0]->getType() << DeletedFD;
13942 }
13943
13944 // The user probably meant to call this special member. Just
13945 // explain why it's deleted.
13946 NoteDeletedFunction(DeletedFD);
13947 return ExprError();
13948 }
13949 CandidateSet.NoteCandidates(
13950 PartialDiagnosticAt(
13951 OpLoc, PDiag(diag::err_ovl_deleted_oper)
13952 << getOperatorSpelling(Best->Function->getDeclName()
13953 .getCXXOverloadedOperator())
13954 << Args[0]->getSourceRange()
13955 << Args[1]->getSourceRange()),
13956 *this, OCD_AllCandidates, Args, BinaryOperator::getOpcodeStr(Opc),
13957 OpLoc);
13958 return ExprError();
13959 }
13960
13961 // We matched a built-in operator; build it.
13962 return CreateBuiltinBinOp(OpLoc, Opc, Args[0], Args[1]);
13963 }
13964
BuildSynthesizedThreeWayComparison(SourceLocation OpLoc,const UnresolvedSetImpl & Fns,Expr * LHS,Expr * RHS,FunctionDecl * DefaultedFn)13965 ExprResult Sema::BuildSynthesizedThreeWayComparison(
13966 SourceLocation OpLoc, const UnresolvedSetImpl &Fns, Expr *LHS, Expr *RHS,
13967 FunctionDecl *DefaultedFn) {
13968 const ComparisonCategoryInfo *Info =
13969 Context.CompCategories.lookupInfoForType(DefaultedFn->getReturnType());
13970 // If we're not producing a known comparison category type, we can't
13971 // synthesize a three-way comparison. Let the caller diagnose this.
13972 if (!Info)
13973 return ExprResult((Expr*)nullptr);
13974
13975 // If we ever want to perform this synthesis more generally, we will need to
13976 // apply the temporary materialization conversion to the operands.
13977 assert(LHS->isGLValue() && RHS->isGLValue() &&
13978 "cannot use prvalue expressions more than once");
13979 Expr *OrigLHS = LHS;
13980 Expr *OrigRHS = RHS;
13981
13982 // Replace the LHS and RHS with OpaqueValueExprs; we're going to refer to
13983 // each of them multiple times below.
13984 LHS = new (Context)
13985 OpaqueValueExpr(LHS->getExprLoc(), LHS->getType(), LHS->getValueKind(),
13986 LHS->getObjectKind(), LHS);
13987 RHS = new (Context)
13988 OpaqueValueExpr(RHS->getExprLoc(), RHS->getType(), RHS->getValueKind(),
13989 RHS->getObjectKind(), RHS);
13990
13991 ExprResult Eq = CreateOverloadedBinOp(OpLoc, BO_EQ, Fns, LHS, RHS, true, true,
13992 DefaultedFn);
13993 if (Eq.isInvalid())
13994 return ExprError();
13995
13996 ExprResult Less = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, LHS, RHS, true,
13997 true, DefaultedFn);
13998 if (Less.isInvalid())
13999 return ExprError();
14000
14001 ExprResult Greater;
14002 if (Info->isPartial()) {
14003 Greater = CreateOverloadedBinOp(OpLoc, BO_LT, Fns, RHS, LHS, true, true,
14004 DefaultedFn);
14005 if (Greater.isInvalid())
14006 return ExprError();
14007 }
14008
14009 // Form the list of comparisons we're going to perform.
14010 struct Comparison {
14011 ExprResult Cmp;
14012 ComparisonCategoryResult Result;
14013 } Comparisons[4] =
14014 { {Eq, Info->isStrong() ? ComparisonCategoryResult::Equal
14015 : ComparisonCategoryResult::Equivalent},
14016 {Less, ComparisonCategoryResult::Less},
14017 {Greater, ComparisonCategoryResult::Greater},
14018 {ExprResult(), ComparisonCategoryResult::Unordered},
14019 };
14020
14021 int I = Info->isPartial() ? 3 : 2;
14022
14023 // Combine the comparisons with suitable conditional expressions.
14024 ExprResult Result;
14025 for (; I >= 0; --I) {
14026 // Build a reference to the comparison category constant.
14027 auto *VI = Info->lookupValueInfo(Comparisons[I].Result);
14028 // FIXME: Missing a constant for a comparison category. Diagnose this?
14029 if (!VI)
14030 return ExprResult((Expr*)nullptr);
14031 ExprResult ThisResult =
14032 BuildDeclarationNameExpr(CXXScopeSpec(), DeclarationNameInfo(), VI->VD);
14033 if (ThisResult.isInvalid())
14034 return ExprError();
14035
14036 // Build a conditional unless this is the final case.
14037 if (Result.get()) {
14038 Result = ActOnConditionalOp(OpLoc, OpLoc, Comparisons[I].Cmp.get(),
14039 ThisResult.get(), Result.get());
14040 if (Result.isInvalid())
14041 return ExprError();
14042 } else {
14043 Result = ThisResult;
14044 }
14045 }
14046
14047 // Build a PseudoObjectExpr to model the rewriting of an <=> operator, and to
14048 // bind the OpaqueValueExprs before they're (repeatedly) used.
14049 Expr *SyntacticForm = BinaryOperator::Create(
14050 Context, OrigLHS, OrigRHS, BO_Cmp, Result.get()->getType(),
14051 Result.get()->getValueKind(), Result.get()->getObjectKind(), OpLoc,
14052 CurFPFeatureOverrides());
14053 Expr *SemanticForm[] = {LHS, RHS, Result.get()};
14054 return PseudoObjectExpr::Create(Context, SyntacticForm, SemanticForm, 2);
14055 }
14056
14057 ExprResult
CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,SourceLocation RLoc,Expr * Base,Expr * Idx)14058 Sema::CreateOverloadedArraySubscriptExpr(SourceLocation LLoc,
14059 SourceLocation RLoc,
14060 Expr *Base, Expr *Idx) {
14061 Expr *Args[2] = { Base, Idx };
14062 DeclarationName OpName =
14063 Context.DeclarationNames.getCXXOperatorName(OO_Subscript);
14064
14065 // If either side is type-dependent, create an appropriate dependent
14066 // expression.
14067 if (Args[0]->isTypeDependent() || Args[1]->isTypeDependent()) {
14068
14069 CXXRecordDecl *NamingClass = nullptr; // lookup ignores member operators
14070 // CHECKME: no 'operator' keyword?
14071 DeclarationNameInfo OpNameInfo(OpName, LLoc);
14072 OpNameInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
14073 ExprResult Fn = CreateUnresolvedLookupExpr(
14074 NamingClass, NestedNameSpecifierLoc(), OpNameInfo, UnresolvedSet<0>());
14075 if (Fn.isInvalid())
14076 return ExprError();
14077 // Can't add any actual overloads yet
14078
14079 return CXXOperatorCallExpr::Create(Context, OO_Subscript, Fn.get(), Args,
14080 Context.DependentTy, VK_PRValue, RLoc,
14081 CurFPFeatureOverrides());
14082 }
14083
14084 // Handle placeholders on both operands.
14085 if (checkPlaceholderForOverload(*this, Args[0]))
14086 return ExprError();
14087 if (checkPlaceholderForOverload(*this, Args[1]))
14088 return ExprError();
14089
14090 // Build an empty overload set.
14091 OverloadCandidateSet CandidateSet(LLoc, OverloadCandidateSet::CSK_Operator);
14092
14093 // Subscript can only be overloaded as a member function.
14094
14095 // Add operator candidates that are member functions.
14096 AddMemberOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
14097
14098 // Add builtin operator candidates.
14099 AddBuiltinOperatorCandidates(OO_Subscript, LLoc, Args, CandidateSet);
14100
14101 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14102
14103 // Perform overload resolution.
14104 OverloadCandidateSet::iterator Best;
14105 switch (CandidateSet.BestViableFunction(*this, LLoc, Best)) {
14106 case OR_Success: {
14107 // We found a built-in operator or an overloaded operator.
14108 FunctionDecl *FnDecl = Best->Function;
14109
14110 if (FnDecl) {
14111 // We matched an overloaded operator. Build a call to that
14112 // operator.
14113
14114 CheckMemberOperatorAccess(LLoc, Args[0], Args[1], Best->FoundDecl);
14115
14116 // Convert the arguments.
14117 CXXMethodDecl *Method = cast<CXXMethodDecl>(FnDecl);
14118 ExprResult Arg0 =
14119 PerformObjectArgumentInitialization(Args[0], /*Qualifier=*/nullptr,
14120 Best->FoundDecl, Method);
14121 if (Arg0.isInvalid())
14122 return ExprError();
14123 Args[0] = Arg0.get();
14124
14125 // Convert the arguments.
14126 ExprResult InputInit
14127 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
14128 Context,
14129 FnDecl->getParamDecl(0)),
14130 SourceLocation(),
14131 Args[1]);
14132 if (InputInit.isInvalid())
14133 return ExprError();
14134
14135 Args[1] = InputInit.getAs<Expr>();
14136
14137 // Build the actual expression node.
14138 DeclarationNameInfo OpLocInfo(OpName, LLoc);
14139 OpLocInfo.setCXXOperatorNameRange(SourceRange(LLoc, RLoc));
14140 ExprResult FnExpr = CreateFunctionRefExpr(*this, FnDecl,
14141 Best->FoundDecl,
14142 Base,
14143 HadMultipleCandidates,
14144 OpLocInfo.getLoc(),
14145 OpLocInfo.getInfo());
14146 if (FnExpr.isInvalid())
14147 return ExprError();
14148
14149 // Determine the result type
14150 QualType ResultTy = FnDecl->getReturnType();
14151 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14152 ResultTy = ResultTy.getNonLValueExprType(Context);
14153
14154 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
14155 Context, OO_Subscript, FnExpr.get(), Args, ResultTy, VK, RLoc,
14156 CurFPFeatureOverrides());
14157 if (CheckCallReturnType(FnDecl->getReturnType(), LLoc, TheCall, FnDecl))
14158 return ExprError();
14159
14160 if (CheckFunctionCall(Method, TheCall,
14161 Method->getType()->castAs<FunctionProtoType>()))
14162 return ExprError();
14163
14164 return MaybeBindToTemporary(TheCall);
14165 } else {
14166 // We matched a built-in operator. Convert the arguments, then
14167 // break out so that we will build the appropriate built-in
14168 // operator node.
14169 ExprResult ArgsRes0 = PerformImplicitConversion(
14170 Args[0], Best->BuiltinParamTypes[0], Best->Conversions[0],
14171 AA_Passing, CCK_ForBuiltinOverloadedOp);
14172 if (ArgsRes0.isInvalid())
14173 return ExprError();
14174 Args[0] = ArgsRes0.get();
14175
14176 ExprResult ArgsRes1 = PerformImplicitConversion(
14177 Args[1], Best->BuiltinParamTypes[1], Best->Conversions[1],
14178 AA_Passing, CCK_ForBuiltinOverloadedOp);
14179 if (ArgsRes1.isInvalid())
14180 return ExprError();
14181 Args[1] = ArgsRes1.get();
14182
14183 break;
14184 }
14185 }
14186
14187 case OR_No_Viable_Function: {
14188 PartialDiagnostic PD = CandidateSet.empty()
14189 ? (PDiag(diag::err_ovl_no_oper)
14190 << Args[0]->getType() << /*subscript*/ 0
14191 << Args[0]->getSourceRange() << Args[1]->getSourceRange())
14192 : (PDiag(diag::err_ovl_no_viable_subscript)
14193 << Args[0]->getType() << Args[0]->getSourceRange()
14194 << Args[1]->getSourceRange());
14195 CandidateSet.NoteCandidates(PartialDiagnosticAt(LLoc, PD), *this,
14196 OCD_AllCandidates, Args, "[]", LLoc);
14197 return ExprError();
14198 }
14199
14200 case OR_Ambiguous:
14201 CandidateSet.NoteCandidates(
14202 PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_ambiguous_oper_binary)
14203 << "[]" << Args[0]->getType()
14204 << Args[1]->getType()
14205 << Args[0]->getSourceRange()
14206 << Args[1]->getSourceRange()),
14207 *this, OCD_AmbiguousCandidates, Args, "[]", LLoc);
14208 return ExprError();
14209
14210 case OR_Deleted:
14211 CandidateSet.NoteCandidates(
14212 PartialDiagnosticAt(LLoc, PDiag(diag::err_ovl_deleted_oper)
14213 << "[]" << Args[0]->getSourceRange()
14214 << Args[1]->getSourceRange()),
14215 *this, OCD_AllCandidates, Args, "[]", LLoc);
14216 return ExprError();
14217 }
14218
14219 // We matched a built-in operator; build it.
14220 return CreateBuiltinArraySubscriptExpr(Args[0], LLoc, Args[1], RLoc);
14221 }
14222
14223 /// BuildCallToMemberFunction - Build a call to a member
14224 /// function. MemExpr is the expression that refers to the member
14225 /// function (and includes the object parameter), Args/NumArgs are the
14226 /// arguments to the function call (not including the object
14227 /// parameter). The caller needs to validate that the member
14228 /// expression refers to a non-static member function or an overloaded
14229 /// member function.
BuildCallToMemberFunction(Scope * S,Expr * MemExprE,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc,Expr * ExecConfig,bool IsExecConfig,bool AllowRecovery)14230 ExprResult Sema::BuildCallToMemberFunction(Scope *S, Expr *MemExprE,
14231 SourceLocation LParenLoc,
14232 MultiExprArg Args,
14233 SourceLocation RParenLoc,
14234 Expr *ExecConfig, bool IsExecConfig,
14235 bool AllowRecovery) {
14236 assert(MemExprE->getType() == Context.BoundMemberTy ||
14237 MemExprE->getType() == Context.OverloadTy);
14238
14239 // Dig out the member expression. This holds both the object
14240 // argument and the member function we're referring to.
14241 Expr *NakedMemExpr = MemExprE->IgnoreParens();
14242
14243 // Determine whether this is a call to a pointer-to-member function.
14244 if (BinaryOperator *op = dyn_cast<BinaryOperator>(NakedMemExpr)) {
14245 assert(op->getType() == Context.BoundMemberTy);
14246 assert(op->getOpcode() == BO_PtrMemD || op->getOpcode() == BO_PtrMemI);
14247
14248 QualType fnType =
14249 op->getRHS()->getType()->castAs<MemberPointerType>()->getPointeeType();
14250
14251 const FunctionProtoType *proto = fnType->castAs<FunctionProtoType>();
14252 QualType resultType = proto->getCallResultType(Context);
14253 ExprValueKind valueKind = Expr::getValueKindForType(proto->getReturnType());
14254
14255 // Check that the object type isn't more qualified than the
14256 // member function we're calling.
14257 Qualifiers funcQuals = proto->getMethodQuals();
14258
14259 QualType objectType = op->getLHS()->getType();
14260 if (op->getOpcode() == BO_PtrMemI)
14261 objectType = objectType->castAs<PointerType>()->getPointeeType();
14262 Qualifiers objectQuals = objectType.getQualifiers();
14263
14264 Qualifiers difference = objectQuals - funcQuals;
14265 difference.removeObjCGCAttr();
14266 difference.removeAddressSpace();
14267 if (difference) {
14268 std::string qualsString = difference.getAsString();
14269 Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
14270 << fnType.getUnqualifiedType()
14271 << qualsString
14272 << (qualsString.find(' ') == std::string::npos ? 1 : 2);
14273 }
14274
14275 CXXMemberCallExpr *call = CXXMemberCallExpr::Create(
14276 Context, MemExprE, Args, resultType, valueKind, RParenLoc,
14277 CurFPFeatureOverrides(), proto->getNumParams());
14278
14279 if (CheckCallReturnType(proto->getReturnType(), op->getRHS()->getBeginLoc(),
14280 call, nullptr))
14281 return ExprError();
14282
14283 if (ConvertArgumentsForCall(call, op, nullptr, proto, Args, RParenLoc))
14284 return ExprError();
14285
14286 if (CheckOtherCall(call, proto))
14287 return ExprError();
14288
14289 return MaybeBindToTemporary(call);
14290 }
14291
14292 // We only try to build a recovery expr at this level if we can preserve
14293 // the return type, otherwise we return ExprError() and let the caller
14294 // recover.
14295 auto BuildRecoveryExpr = [&](QualType Type) {
14296 if (!AllowRecovery)
14297 return ExprError();
14298 std::vector<Expr *> SubExprs = {MemExprE};
14299 llvm::for_each(Args, [&SubExprs](Expr *E) { SubExprs.push_back(E); });
14300 return CreateRecoveryExpr(MemExprE->getBeginLoc(), RParenLoc, SubExprs,
14301 Type);
14302 };
14303 if (isa<CXXPseudoDestructorExpr>(NakedMemExpr))
14304 return CallExpr::Create(Context, MemExprE, Args, Context.VoidTy, VK_PRValue,
14305 RParenLoc, CurFPFeatureOverrides());
14306
14307 UnbridgedCastsSet UnbridgedCasts;
14308 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
14309 return ExprError();
14310
14311 MemberExpr *MemExpr;
14312 CXXMethodDecl *Method = nullptr;
14313 DeclAccessPair FoundDecl = DeclAccessPair::make(nullptr, AS_public);
14314 NestedNameSpecifier *Qualifier = nullptr;
14315 if (isa<MemberExpr>(NakedMemExpr)) {
14316 MemExpr = cast<MemberExpr>(NakedMemExpr);
14317 Method = cast<CXXMethodDecl>(MemExpr->getMemberDecl());
14318 FoundDecl = MemExpr->getFoundDecl();
14319 Qualifier = MemExpr->getQualifier();
14320 UnbridgedCasts.restore();
14321 } else {
14322 UnresolvedMemberExpr *UnresExpr = cast<UnresolvedMemberExpr>(NakedMemExpr);
14323 Qualifier = UnresExpr->getQualifier();
14324
14325 QualType ObjectType = UnresExpr->getBaseType();
14326 Expr::Classification ObjectClassification
14327 = UnresExpr->isArrow()? Expr::Classification::makeSimpleLValue()
14328 : UnresExpr->getBase()->Classify(Context);
14329
14330 // Add overload candidates
14331 OverloadCandidateSet CandidateSet(UnresExpr->getMemberLoc(),
14332 OverloadCandidateSet::CSK_Normal);
14333
14334 // FIXME: avoid copy.
14335 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
14336 if (UnresExpr->hasExplicitTemplateArgs()) {
14337 UnresExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
14338 TemplateArgs = &TemplateArgsBuffer;
14339 }
14340
14341 for (UnresolvedMemberExpr::decls_iterator I = UnresExpr->decls_begin(),
14342 E = UnresExpr->decls_end(); I != E; ++I) {
14343
14344 NamedDecl *Func = *I;
14345 CXXRecordDecl *ActingDC = cast<CXXRecordDecl>(Func->getDeclContext());
14346 if (isa<UsingShadowDecl>(Func))
14347 Func = cast<UsingShadowDecl>(Func)->getTargetDecl();
14348
14349
14350 // Microsoft supports direct constructor calls.
14351 if (getLangOpts().MicrosoftExt && isa<CXXConstructorDecl>(Func)) {
14352 AddOverloadCandidate(cast<CXXConstructorDecl>(Func), I.getPair(), Args,
14353 CandidateSet,
14354 /*SuppressUserConversions*/ false);
14355 } else if ((Method = dyn_cast<CXXMethodDecl>(Func))) {
14356 // If explicit template arguments were provided, we can't call a
14357 // non-template member function.
14358 if (TemplateArgs)
14359 continue;
14360
14361 AddMethodCandidate(Method, I.getPair(), ActingDC, ObjectType,
14362 ObjectClassification, Args, CandidateSet,
14363 /*SuppressUserConversions=*/false);
14364 } else {
14365 AddMethodTemplateCandidate(
14366 cast<FunctionTemplateDecl>(Func), I.getPair(), ActingDC,
14367 TemplateArgs, ObjectType, ObjectClassification, Args, CandidateSet,
14368 /*SuppressUserConversions=*/false);
14369 }
14370 }
14371
14372 DeclarationName DeclName = UnresExpr->getMemberName();
14373
14374 UnbridgedCasts.restore();
14375
14376 OverloadCandidateSet::iterator Best;
14377 bool Succeeded = false;
14378 switch (CandidateSet.BestViableFunction(*this, UnresExpr->getBeginLoc(),
14379 Best)) {
14380 case OR_Success:
14381 Method = cast<CXXMethodDecl>(Best->Function);
14382 FoundDecl = Best->FoundDecl;
14383 CheckUnresolvedMemberAccess(UnresExpr, Best->FoundDecl);
14384 if (DiagnoseUseOfDecl(Best->FoundDecl, UnresExpr->getNameLoc()))
14385 break;
14386 // If FoundDecl is different from Method (such as if one is a template
14387 // and the other a specialization), make sure DiagnoseUseOfDecl is
14388 // called on both.
14389 // FIXME: This would be more comprehensively addressed by modifying
14390 // DiagnoseUseOfDecl to accept both the FoundDecl and the decl
14391 // being used.
14392 if (Method != FoundDecl.getDecl() &&
14393 DiagnoseUseOfDecl(Method, UnresExpr->getNameLoc()))
14394 break;
14395 Succeeded = true;
14396 break;
14397
14398 case OR_No_Viable_Function:
14399 CandidateSet.NoteCandidates(
14400 PartialDiagnosticAt(
14401 UnresExpr->getMemberLoc(),
14402 PDiag(diag::err_ovl_no_viable_member_function_in_call)
14403 << DeclName << MemExprE->getSourceRange()),
14404 *this, OCD_AllCandidates, Args);
14405 break;
14406 case OR_Ambiguous:
14407 CandidateSet.NoteCandidates(
14408 PartialDiagnosticAt(UnresExpr->getMemberLoc(),
14409 PDiag(diag::err_ovl_ambiguous_member_call)
14410 << DeclName << MemExprE->getSourceRange()),
14411 *this, OCD_AmbiguousCandidates, Args);
14412 break;
14413 case OR_Deleted:
14414 CandidateSet.NoteCandidates(
14415 PartialDiagnosticAt(UnresExpr->getMemberLoc(),
14416 PDiag(diag::err_ovl_deleted_member_call)
14417 << DeclName << MemExprE->getSourceRange()),
14418 *this, OCD_AllCandidates, Args);
14419 break;
14420 }
14421 // Overload resolution fails, try to recover.
14422 if (!Succeeded)
14423 return BuildRecoveryExpr(chooseRecoveryType(CandidateSet, &Best));
14424
14425 MemExprE = FixOverloadedFunctionReference(MemExprE, FoundDecl, Method);
14426
14427 // If overload resolution picked a static member, build a
14428 // non-member call based on that function.
14429 if (Method->isStatic()) {
14430 return BuildResolvedCallExpr(MemExprE, Method, LParenLoc, Args, RParenLoc,
14431 ExecConfig, IsExecConfig);
14432 }
14433
14434 MemExpr = cast<MemberExpr>(MemExprE->IgnoreParens());
14435 }
14436
14437 QualType ResultType = Method->getReturnType();
14438 ExprValueKind VK = Expr::getValueKindForType(ResultType);
14439 ResultType = ResultType.getNonLValueExprType(Context);
14440
14441 assert(Method && "Member call to something that isn't a method?");
14442 const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
14443 CXXMemberCallExpr *TheCall = CXXMemberCallExpr::Create(
14444 Context, MemExprE, Args, ResultType, VK, RParenLoc,
14445 CurFPFeatureOverrides(), Proto->getNumParams());
14446
14447 // Check for a valid return type.
14448 if (CheckCallReturnType(Method->getReturnType(), MemExpr->getMemberLoc(),
14449 TheCall, Method))
14450 return BuildRecoveryExpr(ResultType);
14451
14452 // Convert the object argument (for a non-static member function call).
14453 // We only need to do this if there was actually an overload; otherwise
14454 // it was done at lookup.
14455 if (!Method->isStatic()) {
14456 ExprResult ObjectArg =
14457 PerformObjectArgumentInitialization(MemExpr->getBase(), Qualifier,
14458 FoundDecl, Method);
14459 if (ObjectArg.isInvalid())
14460 return ExprError();
14461 MemExpr->setBase(ObjectArg.get());
14462 }
14463
14464 // Convert the rest of the arguments
14465 if (ConvertArgumentsForCall(TheCall, MemExpr, Method, Proto, Args,
14466 RParenLoc))
14467 return BuildRecoveryExpr(ResultType);
14468
14469 DiagnoseSentinelCalls(Method, LParenLoc, Args);
14470
14471 if (CheckFunctionCall(Method, TheCall, Proto))
14472 return ExprError();
14473
14474 // In the case the method to call was not selected by the overloading
14475 // resolution process, we still need to handle the enable_if attribute. Do
14476 // that here, so it will not hide previous -- and more relevant -- errors.
14477 if (auto *MemE = dyn_cast<MemberExpr>(NakedMemExpr)) {
14478 if (const EnableIfAttr *Attr =
14479 CheckEnableIf(Method, LParenLoc, Args, true)) {
14480 Diag(MemE->getMemberLoc(),
14481 diag::err_ovl_no_viable_member_function_in_call)
14482 << Method << Method->getSourceRange();
14483 Diag(Method->getLocation(),
14484 diag::note_ovl_candidate_disabled_by_function_cond_attr)
14485 << Attr->getCond()->getSourceRange() << Attr->getMessage();
14486 return ExprError();
14487 }
14488 }
14489
14490 if ((isa<CXXConstructorDecl>(CurContext) ||
14491 isa<CXXDestructorDecl>(CurContext)) &&
14492 TheCall->getMethodDecl()->isPure()) {
14493 const CXXMethodDecl *MD = TheCall->getMethodDecl();
14494
14495 if (isa<CXXThisExpr>(MemExpr->getBase()->IgnoreParenCasts()) &&
14496 MemExpr->performsVirtualDispatch(getLangOpts())) {
14497 Diag(MemExpr->getBeginLoc(),
14498 diag::warn_call_to_pure_virtual_member_function_from_ctor_dtor)
14499 << MD->getDeclName() << isa<CXXDestructorDecl>(CurContext)
14500 << MD->getParent();
14501
14502 Diag(MD->getBeginLoc(), diag::note_previous_decl) << MD->getDeclName();
14503 if (getLangOpts().AppleKext)
14504 Diag(MemExpr->getBeginLoc(), diag::note_pure_qualified_call_kext)
14505 << MD->getParent() << MD->getDeclName();
14506 }
14507 }
14508
14509 if (CXXDestructorDecl *DD =
14510 dyn_cast<CXXDestructorDecl>(TheCall->getMethodDecl())) {
14511 // a->A::f() doesn't go through the vtable, except in AppleKext mode.
14512 bool CallCanBeVirtual = !MemExpr->hasQualifier() || getLangOpts().AppleKext;
14513 CheckVirtualDtorCall(DD, MemExpr->getBeginLoc(), /*IsDelete=*/false,
14514 CallCanBeVirtual, /*WarnOnNonAbstractTypes=*/true,
14515 MemExpr->getMemberLoc());
14516 }
14517
14518 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall),
14519 TheCall->getMethodDecl());
14520 }
14521
14522 /// BuildCallToObjectOfClassType - Build a call to an object of class
14523 /// type (C++ [over.call.object]), which can end up invoking an
14524 /// overloaded function call operator (@c operator()) or performing a
14525 /// user-defined conversion on the object argument.
14526 ExprResult
BuildCallToObjectOfClassType(Scope * S,Expr * Obj,SourceLocation LParenLoc,MultiExprArg Args,SourceLocation RParenLoc)14527 Sema::BuildCallToObjectOfClassType(Scope *S, Expr *Obj,
14528 SourceLocation LParenLoc,
14529 MultiExprArg Args,
14530 SourceLocation RParenLoc) {
14531 if (checkPlaceholderForOverload(*this, Obj))
14532 return ExprError();
14533 ExprResult Object = Obj;
14534
14535 UnbridgedCastsSet UnbridgedCasts;
14536 if (checkArgPlaceholdersForOverload(*this, Args, UnbridgedCasts))
14537 return ExprError();
14538
14539 assert(Object.get()->getType()->isRecordType() &&
14540 "Requires object type argument");
14541
14542 // C++ [over.call.object]p1:
14543 // If the primary-expression E in the function call syntax
14544 // evaluates to a class object of type "cv T", then the set of
14545 // candidate functions includes at least the function call
14546 // operators of T. The function call operators of T are obtained by
14547 // ordinary lookup of the name operator() in the context of
14548 // (E).operator().
14549 OverloadCandidateSet CandidateSet(LParenLoc,
14550 OverloadCandidateSet::CSK_Operator);
14551 DeclarationName OpName = Context.DeclarationNames.getCXXOperatorName(OO_Call);
14552
14553 if (RequireCompleteType(LParenLoc, Object.get()->getType(),
14554 diag::err_incomplete_object_call, Object.get()))
14555 return true;
14556
14557 const auto *Record = Object.get()->getType()->castAs<RecordType>();
14558 LookupResult R(*this, OpName, LParenLoc, LookupOrdinaryName);
14559 LookupQualifiedName(R, Record->getDecl());
14560 R.suppressDiagnostics();
14561
14562 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
14563 Oper != OperEnd; ++Oper) {
14564 AddMethodCandidate(Oper.getPair(), Object.get()->getType(),
14565 Object.get()->Classify(Context), Args, CandidateSet,
14566 /*SuppressUserConversion=*/false);
14567 }
14568
14569 // C++ [over.call.object]p2:
14570 // In addition, for each (non-explicit in C++0x) conversion function
14571 // declared in T of the form
14572 //
14573 // operator conversion-type-id () cv-qualifier;
14574 //
14575 // where cv-qualifier is the same cv-qualification as, or a
14576 // greater cv-qualification than, cv, and where conversion-type-id
14577 // denotes the type "pointer to function of (P1,...,Pn) returning
14578 // R", or the type "reference to pointer to function of
14579 // (P1,...,Pn) returning R", or the type "reference to function
14580 // of (P1,...,Pn) returning R", a surrogate call function [...]
14581 // is also considered as a candidate function. Similarly,
14582 // surrogate call functions are added to the set of candidate
14583 // functions for each conversion function declared in an
14584 // accessible base class provided the function is not hidden
14585 // within T by another intervening declaration.
14586 const auto &Conversions =
14587 cast<CXXRecordDecl>(Record->getDecl())->getVisibleConversionFunctions();
14588 for (auto I = Conversions.begin(), E = Conversions.end(); I != E; ++I) {
14589 NamedDecl *D = *I;
14590 CXXRecordDecl *ActingContext = cast<CXXRecordDecl>(D->getDeclContext());
14591 if (isa<UsingShadowDecl>(D))
14592 D = cast<UsingShadowDecl>(D)->getTargetDecl();
14593
14594 // Skip over templated conversion functions; they aren't
14595 // surrogates.
14596 if (isa<FunctionTemplateDecl>(D))
14597 continue;
14598
14599 CXXConversionDecl *Conv = cast<CXXConversionDecl>(D);
14600 if (!Conv->isExplicit()) {
14601 // Strip the reference type (if any) and then the pointer type (if
14602 // any) to get down to what might be a function type.
14603 QualType ConvType = Conv->getConversionType().getNonReferenceType();
14604 if (const PointerType *ConvPtrType = ConvType->getAs<PointerType>())
14605 ConvType = ConvPtrType->getPointeeType();
14606
14607 if (const FunctionProtoType *Proto = ConvType->getAs<FunctionProtoType>())
14608 {
14609 AddSurrogateCandidate(Conv, I.getPair(), ActingContext, Proto,
14610 Object.get(), Args, CandidateSet);
14611 }
14612 }
14613 }
14614
14615 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14616
14617 // Perform overload resolution.
14618 OverloadCandidateSet::iterator Best;
14619 switch (CandidateSet.BestViableFunction(*this, Object.get()->getBeginLoc(),
14620 Best)) {
14621 case OR_Success:
14622 // Overload resolution succeeded; we'll build the appropriate call
14623 // below.
14624 break;
14625
14626 case OR_No_Viable_Function: {
14627 PartialDiagnostic PD =
14628 CandidateSet.empty()
14629 ? (PDiag(diag::err_ovl_no_oper)
14630 << Object.get()->getType() << /*call*/ 1
14631 << Object.get()->getSourceRange())
14632 : (PDiag(diag::err_ovl_no_viable_object_call)
14633 << Object.get()->getType() << Object.get()->getSourceRange());
14634 CandidateSet.NoteCandidates(
14635 PartialDiagnosticAt(Object.get()->getBeginLoc(), PD), *this,
14636 OCD_AllCandidates, Args);
14637 break;
14638 }
14639 case OR_Ambiguous:
14640 CandidateSet.NoteCandidates(
14641 PartialDiagnosticAt(Object.get()->getBeginLoc(),
14642 PDiag(diag::err_ovl_ambiguous_object_call)
14643 << Object.get()->getType()
14644 << Object.get()->getSourceRange()),
14645 *this, OCD_AmbiguousCandidates, Args);
14646 break;
14647
14648 case OR_Deleted:
14649 CandidateSet.NoteCandidates(
14650 PartialDiagnosticAt(Object.get()->getBeginLoc(),
14651 PDiag(diag::err_ovl_deleted_object_call)
14652 << Object.get()->getType()
14653 << Object.get()->getSourceRange()),
14654 *this, OCD_AllCandidates, Args);
14655 break;
14656 }
14657
14658 if (Best == CandidateSet.end())
14659 return true;
14660
14661 UnbridgedCasts.restore();
14662
14663 if (Best->Function == nullptr) {
14664 // Since there is no function declaration, this is one of the
14665 // surrogate candidates. Dig out the conversion function.
14666 CXXConversionDecl *Conv
14667 = cast<CXXConversionDecl>(
14668 Best->Conversions[0].UserDefined.ConversionFunction);
14669
14670 CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr,
14671 Best->FoundDecl);
14672 if (DiagnoseUseOfDecl(Best->FoundDecl, LParenLoc))
14673 return ExprError();
14674 assert(Conv == Best->FoundDecl.getDecl() &&
14675 "Found Decl & conversion-to-functionptr should be same, right?!");
14676 // We selected one of the surrogate functions that converts the
14677 // object parameter to a function pointer. Perform the conversion
14678 // on the object argument, then let BuildCallExpr finish the job.
14679
14680 // Create an implicit member expr to refer to the conversion operator.
14681 // and then call it.
14682 ExprResult Call = BuildCXXMemberCallExpr(Object.get(), Best->FoundDecl,
14683 Conv, HadMultipleCandidates);
14684 if (Call.isInvalid())
14685 return ExprError();
14686 // Record usage of conversion in an implicit cast.
14687 Call = ImplicitCastExpr::Create(
14688 Context, Call.get()->getType(), CK_UserDefinedConversion, Call.get(),
14689 nullptr, VK_PRValue, CurFPFeatureOverrides());
14690
14691 return BuildCallExpr(S, Call.get(), LParenLoc, Args, RParenLoc);
14692 }
14693
14694 CheckMemberOperatorAccess(LParenLoc, Object.get(), nullptr, Best->FoundDecl);
14695
14696 // We found an overloaded operator(). Build a CXXOperatorCallExpr
14697 // that calls this method, using Object for the implicit object
14698 // parameter and passing along the remaining arguments.
14699 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
14700
14701 // An error diagnostic has already been printed when parsing the declaration.
14702 if (Method->isInvalidDecl())
14703 return ExprError();
14704
14705 const auto *Proto = Method->getType()->castAs<FunctionProtoType>();
14706 unsigned NumParams = Proto->getNumParams();
14707
14708 DeclarationNameInfo OpLocInfo(
14709 Context.DeclarationNames.getCXXOperatorName(OO_Call), LParenLoc);
14710 OpLocInfo.setCXXOperatorNameRange(SourceRange(LParenLoc, RParenLoc));
14711 ExprResult NewFn = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
14712 Obj, HadMultipleCandidates,
14713 OpLocInfo.getLoc(),
14714 OpLocInfo.getInfo());
14715 if (NewFn.isInvalid())
14716 return true;
14717
14718 // The number of argument slots to allocate in the call. If we have default
14719 // arguments we need to allocate space for them as well. We additionally
14720 // need one more slot for the object parameter.
14721 unsigned NumArgsSlots = 1 + std::max<unsigned>(Args.size(), NumParams);
14722
14723 // Build the full argument list for the method call (the implicit object
14724 // parameter is placed at the beginning of the list).
14725 SmallVector<Expr *, 8> MethodArgs(NumArgsSlots);
14726
14727 bool IsError = false;
14728
14729 // Initialize the implicit object parameter.
14730 ExprResult ObjRes =
14731 PerformObjectArgumentInitialization(Object.get(), /*Qualifier=*/nullptr,
14732 Best->FoundDecl, Method);
14733 if (ObjRes.isInvalid())
14734 IsError = true;
14735 else
14736 Object = ObjRes;
14737 MethodArgs[0] = Object.get();
14738
14739 // Check the argument types.
14740 for (unsigned i = 0; i != NumParams; i++) {
14741 Expr *Arg;
14742 if (i < Args.size()) {
14743 Arg = Args[i];
14744
14745 // Pass the argument.
14746
14747 ExprResult InputInit
14748 = PerformCopyInitialization(InitializedEntity::InitializeParameter(
14749 Context,
14750 Method->getParamDecl(i)),
14751 SourceLocation(), Arg);
14752
14753 IsError |= InputInit.isInvalid();
14754 Arg = InputInit.getAs<Expr>();
14755 } else {
14756 ExprResult DefArg
14757 = BuildCXXDefaultArgExpr(LParenLoc, Method, Method->getParamDecl(i));
14758 if (DefArg.isInvalid()) {
14759 IsError = true;
14760 break;
14761 }
14762
14763 Arg = DefArg.getAs<Expr>();
14764 }
14765
14766 MethodArgs[i + 1] = Arg;
14767 }
14768
14769 // If this is a variadic call, handle args passed through "...".
14770 if (Proto->isVariadic()) {
14771 // Promote the arguments (C99 6.5.2.2p7).
14772 for (unsigned i = NumParams, e = Args.size(); i < e; i++) {
14773 ExprResult Arg = DefaultVariadicArgumentPromotion(Args[i], VariadicMethod,
14774 nullptr);
14775 IsError |= Arg.isInvalid();
14776 MethodArgs[i + 1] = Arg.get();
14777 }
14778 }
14779
14780 if (IsError)
14781 return true;
14782
14783 DiagnoseSentinelCalls(Method, LParenLoc, Args);
14784
14785 // Once we've built TheCall, all of the expressions are properly owned.
14786 QualType ResultTy = Method->getReturnType();
14787 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14788 ResultTy = ResultTy.getNonLValueExprType(Context);
14789
14790 CXXOperatorCallExpr *TheCall = CXXOperatorCallExpr::Create(
14791 Context, OO_Call, NewFn.get(), MethodArgs, ResultTy, VK, RParenLoc,
14792 CurFPFeatureOverrides());
14793
14794 if (CheckCallReturnType(Method->getReturnType(), LParenLoc, TheCall, Method))
14795 return true;
14796
14797 if (CheckFunctionCall(Method, TheCall, Proto))
14798 return true;
14799
14800 return CheckForImmediateInvocation(MaybeBindToTemporary(TheCall), Method);
14801 }
14802
14803 /// BuildOverloadedArrowExpr - Build a call to an overloaded @c operator->
14804 /// (if one exists), where @c Base is an expression of class type and
14805 /// @c Member is the name of the member we're trying to find.
14806 ExprResult
BuildOverloadedArrowExpr(Scope * S,Expr * Base,SourceLocation OpLoc,bool * NoArrowOperatorFound)14807 Sema::BuildOverloadedArrowExpr(Scope *S, Expr *Base, SourceLocation OpLoc,
14808 bool *NoArrowOperatorFound) {
14809 assert(Base->getType()->isRecordType() &&
14810 "left-hand side must have class type");
14811
14812 if (checkPlaceholderForOverload(*this, Base))
14813 return ExprError();
14814
14815 SourceLocation Loc = Base->getExprLoc();
14816
14817 // C++ [over.ref]p1:
14818 //
14819 // [...] An expression x->m is interpreted as (x.operator->())->m
14820 // for a class object x of type T if T::operator->() exists and if
14821 // the operator is selected as the best match function by the
14822 // overload resolution mechanism (13.3).
14823 DeclarationName OpName =
14824 Context.DeclarationNames.getCXXOperatorName(OO_Arrow);
14825 OverloadCandidateSet CandidateSet(Loc, OverloadCandidateSet::CSK_Operator);
14826
14827 if (RequireCompleteType(Loc, Base->getType(),
14828 diag::err_typecheck_incomplete_tag, Base))
14829 return ExprError();
14830
14831 LookupResult R(*this, OpName, OpLoc, LookupOrdinaryName);
14832 LookupQualifiedName(R, Base->getType()->castAs<RecordType>()->getDecl());
14833 R.suppressDiagnostics();
14834
14835 for (LookupResult::iterator Oper = R.begin(), OperEnd = R.end();
14836 Oper != OperEnd; ++Oper) {
14837 AddMethodCandidate(Oper.getPair(), Base->getType(), Base->Classify(Context),
14838 None, CandidateSet, /*SuppressUserConversion=*/false);
14839 }
14840
14841 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14842
14843 // Perform overload resolution.
14844 OverloadCandidateSet::iterator Best;
14845 switch (CandidateSet.BestViableFunction(*this, OpLoc, Best)) {
14846 case OR_Success:
14847 // Overload resolution succeeded; we'll build the call below.
14848 break;
14849
14850 case OR_No_Viable_Function: {
14851 auto Cands = CandidateSet.CompleteCandidates(*this, OCD_AllCandidates, Base);
14852 if (CandidateSet.empty()) {
14853 QualType BaseType = Base->getType();
14854 if (NoArrowOperatorFound) {
14855 // Report this specific error to the caller instead of emitting a
14856 // diagnostic, as requested.
14857 *NoArrowOperatorFound = true;
14858 return ExprError();
14859 }
14860 Diag(OpLoc, diag::err_typecheck_member_reference_arrow)
14861 << BaseType << Base->getSourceRange();
14862 if (BaseType->isRecordType() && !BaseType->isPointerType()) {
14863 Diag(OpLoc, diag::note_typecheck_member_reference_suggestion)
14864 << FixItHint::CreateReplacement(OpLoc, ".");
14865 }
14866 } else
14867 Diag(OpLoc, diag::err_ovl_no_viable_oper)
14868 << "operator->" << Base->getSourceRange();
14869 CandidateSet.NoteCandidates(*this, Base, Cands);
14870 return ExprError();
14871 }
14872 case OR_Ambiguous:
14873 CandidateSet.NoteCandidates(
14874 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_ambiguous_oper_unary)
14875 << "->" << Base->getType()
14876 << Base->getSourceRange()),
14877 *this, OCD_AmbiguousCandidates, Base);
14878 return ExprError();
14879
14880 case OR_Deleted:
14881 CandidateSet.NoteCandidates(
14882 PartialDiagnosticAt(OpLoc, PDiag(diag::err_ovl_deleted_oper)
14883 << "->" << Base->getSourceRange()),
14884 *this, OCD_AllCandidates, Base);
14885 return ExprError();
14886 }
14887
14888 CheckMemberOperatorAccess(OpLoc, Base, nullptr, Best->FoundDecl);
14889
14890 // Convert the object parameter.
14891 CXXMethodDecl *Method = cast<CXXMethodDecl>(Best->Function);
14892 ExprResult BaseResult =
14893 PerformObjectArgumentInitialization(Base, /*Qualifier=*/nullptr,
14894 Best->FoundDecl, Method);
14895 if (BaseResult.isInvalid())
14896 return ExprError();
14897 Base = BaseResult.get();
14898
14899 // Build the operator call.
14900 ExprResult FnExpr = CreateFunctionRefExpr(*this, Method, Best->FoundDecl,
14901 Base, HadMultipleCandidates, OpLoc);
14902 if (FnExpr.isInvalid())
14903 return ExprError();
14904
14905 QualType ResultTy = Method->getReturnType();
14906 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14907 ResultTy = ResultTy.getNonLValueExprType(Context);
14908 CXXOperatorCallExpr *TheCall =
14909 CXXOperatorCallExpr::Create(Context, OO_Arrow, FnExpr.get(), Base,
14910 ResultTy, VK, OpLoc, CurFPFeatureOverrides());
14911
14912 if (CheckCallReturnType(Method->getReturnType(), OpLoc, TheCall, Method))
14913 return ExprError();
14914
14915 if (CheckFunctionCall(Method, TheCall,
14916 Method->getType()->castAs<FunctionProtoType>()))
14917 return ExprError();
14918
14919 return MaybeBindToTemporary(TheCall);
14920 }
14921
14922 /// BuildLiteralOperatorCall - Build a UserDefinedLiteral by creating a call to
14923 /// a literal operator described by the provided lookup results.
BuildLiteralOperatorCall(LookupResult & R,DeclarationNameInfo & SuffixInfo,ArrayRef<Expr * > Args,SourceLocation LitEndLoc,TemplateArgumentListInfo * TemplateArgs)14924 ExprResult Sema::BuildLiteralOperatorCall(LookupResult &R,
14925 DeclarationNameInfo &SuffixInfo,
14926 ArrayRef<Expr*> Args,
14927 SourceLocation LitEndLoc,
14928 TemplateArgumentListInfo *TemplateArgs) {
14929 SourceLocation UDSuffixLoc = SuffixInfo.getCXXLiteralOperatorNameLoc();
14930
14931 OverloadCandidateSet CandidateSet(UDSuffixLoc,
14932 OverloadCandidateSet::CSK_Normal);
14933 AddNonMemberOperatorCandidates(R.asUnresolvedSet(), Args, CandidateSet,
14934 TemplateArgs);
14935
14936 bool HadMultipleCandidates = (CandidateSet.size() > 1);
14937
14938 // Perform overload resolution. This will usually be trivial, but might need
14939 // to perform substitutions for a literal operator template.
14940 OverloadCandidateSet::iterator Best;
14941 switch (CandidateSet.BestViableFunction(*this, UDSuffixLoc, Best)) {
14942 case OR_Success:
14943 case OR_Deleted:
14944 break;
14945
14946 case OR_No_Viable_Function:
14947 CandidateSet.NoteCandidates(
14948 PartialDiagnosticAt(UDSuffixLoc,
14949 PDiag(diag::err_ovl_no_viable_function_in_call)
14950 << R.getLookupName()),
14951 *this, OCD_AllCandidates, Args);
14952 return ExprError();
14953
14954 case OR_Ambiguous:
14955 CandidateSet.NoteCandidates(
14956 PartialDiagnosticAt(R.getNameLoc(), PDiag(diag::err_ovl_ambiguous_call)
14957 << R.getLookupName()),
14958 *this, OCD_AmbiguousCandidates, Args);
14959 return ExprError();
14960 }
14961
14962 FunctionDecl *FD = Best->Function;
14963 ExprResult Fn = CreateFunctionRefExpr(*this, FD, Best->FoundDecl,
14964 nullptr, HadMultipleCandidates,
14965 SuffixInfo.getLoc(),
14966 SuffixInfo.getInfo());
14967 if (Fn.isInvalid())
14968 return true;
14969
14970 // Check the argument types. This should almost always be a no-op, except
14971 // that array-to-pointer decay is applied to string literals.
14972 Expr *ConvArgs[2];
14973 for (unsigned ArgIdx = 0, N = Args.size(); ArgIdx != N; ++ArgIdx) {
14974 ExprResult InputInit = PerformCopyInitialization(
14975 InitializedEntity::InitializeParameter(Context, FD->getParamDecl(ArgIdx)),
14976 SourceLocation(), Args[ArgIdx]);
14977 if (InputInit.isInvalid())
14978 return true;
14979 ConvArgs[ArgIdx] = InputInit.get();
14980 }
14981
14982 QualType ResultTy = FD->getReturnType();
14983 ExprValueKind VK = Expr::getValueKindForType(ResultTy);
14984 ResultTy = ResultTy.getNonLValueExprType(Context);
14985
14986 UserDefinedLiteral *UDL = UserDefinedLiteral::Create(
14987 Context, Fn.get(), llvm::makeArrayRef(ConvArgs, Args.size()), ResultTy,
14988 VK, LitEndLoc, UDSuffixLoc, CurFPFeatureOverrides());
14989
14990 if (CheckCallReturnType(FD->getReturnType(), UDSuffixLoc, UDL, FD))
14991 return ExprError();
14992
14993 if (CheckFunctionCall(FD, UDL, nullptr))
14994 return ExprError();
14995
14996 return CheckForImmediateInvocation(MaybeBindToTemporary(UDL), FD);
14997 }
14998
14999 /// Build a call to 'begin' or 'end' for a C++11 for-range statement. If the
15000 /// given LookupResult is non-empty, it is assumed to describe a member which
15001 /// will be invoked. Otherwise, the function will be found via argument
15002 /// dependent lookup.
15003 /// CallExpr is set to a valid expression and FRS_Success returned on success,
15004 /// otherwise CallExpr is set to ExprError() and some non-success value
15005 /// is returned.
15006 Sema::ForRangeStatus
BuildForRangeBeginEndCall(SourceLocation Loc,SourceLocation RangeLoc,const DeclarationNameInfo & NameInfo,LookupResult & MemberLookup,OverloadCandidateSet * CandidateSet,Expr * Range,ExprResult * CallExpr)15007 Sema::BuildForRangeBeginEndCall(SourceLocation Loc,
15008 SourceLocation RangeLoc,
15009 const DeclarationNameInfo &NameInfo,
15010 LookupResult &MemberLookup,
15011 OverloadCandidateSet *CandidateSet,
15012 Expr *Range, ExprResult *CallExpr) {
15013 Scope *S = nullptr;
15014
15015 CandidateSet->clear(OverloadCandidateSet::CSK_Normal);
15016 if (!MemberLookup.empty()) {
15017 ExprResult MemberRef =
15018 BuildMemberReferenceExpr(Range, Range->getType(), Loc,
15019 /*IsPtr=*/false, CXXScopeSpec(),
15020 /*TemplateKWLoc=*/SourceLocation(),
15021 /*FirstQualifierInScope=*/nullptr,
15022 MemberLookup,
15023 /*TemplateArgs=*/nullptr, S);
15024 if (MemberRef.isInvalid()) {
15025 *CallExpr = ExprError();
15026 return FRS_DiagnosticIssued;
15027 }
15028 *CallExpr = BuildCallExpr(S, MemberRef.get(), Loc, None, Loc, nullptr);
15029 if (CallExpr->isInvalid()) {
15030 *CallExpr = ExprError();
15031 return FRS_DiagnosticIssued;
15032 }
15033 } else {
15034 ExprResult FnR = CreateUnresolvedLookupExpr(/*NamingClass=*/nullptr,
15035 NestedNameSpecifierLoc(),
15036 NameInfo, UnresolvedSet<0>());
15037 if (FnR.isInvalid())
15038 return FRS_DiagnosticIssued;
15039 UnresolvedLookupExpr *Fn = cast<UnresolvedLookupExpr>(FnR.get());
15040
15041 bool CandidateSetError = buildOverloadedCallSet(S, Fn, Fn, Range, Loc,
15042 CandidateSet, CallExpr);
15043 if (CandidateSet->empty() || CandidateSetError) {
15044 *CallExpr = ExprError();
15045 return FRS_NoViableFunction;
15046 }
15047 OverloadCandidateSet::iterator Best;
15048 OverloadingResult OverloadResult =
15049 CandidateSet->BestViableFunction(*this, Fn->getBeginLoc(), Best);
15050
15051 if (OverloadResult == OR_No_Viable_Function) {
15052 *CallExpr = ExprError();
15053 return FRS_NoViableFunction;
15054 }
15055 *CallExpr = FinishOverloadedCallExpr(*this, S, Fn, Fn, Loc, Range,
15056 Loc, nullptr, CandidateSet, &Best,
15057 OverloadResult,
15058 /*AllowTypoCorrection=*/false);
15059 if (CallExpr->isInvalid() || OverloadResult != OR_Success) {
15060 *CallExpr = ExprError();
15061 return FRS_DiagnosticIssued;
15062 }
15063 }
15064 return FRS_Success;
15065 }
15066
15067
15068 /// FixOverloadedFunctionReference - E is an expression that refers to
15069 /// a C++ overloaded function (possibly with some parentheses and
15070 /// perhaps a '&' around it). We have resolved the overloaded function
15071 /// to the function declaration Fn, so patch up the expression E to
15072 /// refer (possibly indirectly) to Fn. Returns the new expr.
FixOverloadedFunctionReference(Expr * E,DeclAccessPair Found,FunctionDecl * Fn)15073 Expr *Sema::FixOverloadedFunctionReference(Expr *E, DeclAccessPair Found,
15074 FunctionDecl *Fn) {
15075 if (ParenExpr *PE = dyn_cast<ParenExpr>(E)) {
15076 Expr *SubExpr = FixOverloadedFunctionReference(PE->getSubExpr(),
15077 Found, Fn);
15078 if (SubExpr == PE->getSubExpr())
15079 return PE;
15080
15081 return new (Context) ParenExpr(PE->getLParen(), PE->getRParen(), SubExpr);
15082 }
15083
15084 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E)) {
15085 Expr *SubExpr = FixOverloadedFunctionReference(ICE->getSubExpr(),
15086 Found, Fn);
15087 assert(Context.hasSameType(ICE->getSubExpr()->getType(),
15088 SubExpr->getType()) &&
15089 "Implicit cast type cannot be determined from overload");
15090 assert(ICE->path_empty() && "fixing up hierarchy conversion?");
15091 if (SubExpr == ICE->getSubExpr())
15092 return ICE;
15093
15094 return ImplicitCastExpr::Create(Context, ICE->getType(), ICE->getCastKind(),
15095 SubExpr, nullptr, ICE->getValueKind(),
15096 CurFPFeatureOverrides());
15097 }
15098
15099 if (auto *GSE = dyn_cast<GenericSelectionExpr>(E)) {
15100 if (!GSE->isResultDependent()) {
15101 Expr *SubExpr =
15102 FixOverloadedFunctionReference(GSE->getResultExpr(), Found, Fn);
15103 if (SubExpr == GSE->getResultExpr())
15104 return GSE;
15105
15106 // Replace the resulting type information before rebuilding the generic
15107 // selection expression.
15108 ArrayRef<Expr *> A = GSE->getAssocExprs();
15109 SmallVector<Expr *, 4> AssocExprs(A.begin(), A.end());
15110 unsigned ResultIdx = GSE->getResultIndex();
15111 AssocExprs[ResultIdx] = SubExpr;
15112
15113 return GenericSelectionExpr::Create(
15114 Context, GSE->getGenericLoc(), GSE->getControllingExpr(),
15115 GSE->getAssocTypeSourceInfos(), AssocExprs, GSE->getDefaultLoc(),
15116 GSE->getRParenLoc(), GSE->containsUnexpandedParameterPack(),
15117 ResultIdx);
15118 }
15119 // Rather than fall through to the unreachable, return the original generic
15120 // selection expression.
15121 return GSE;
15122 }
15123
15124 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(E)) {
15125 assert(UnOp->getOpcode() == UO_AddrOf &&
15126 "Can only take the address of an overloaded function");
15127 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn)) {
15128 if (Method->isStatic()) {
15129 // Do nothing: static member functions aren't any different
15130 // from non-member functions.
15131 } else {
15132 // Fix the subexpression, which really has to be an
15133 // UnresolvedLookupExpr holding an overloaded member function
15134 // or template.
15135 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
15136 Found, Fn);
15137 if (SubExpr == UnOp->getSubExpr())
15138 return UnOp;
15139
15140 assert(isa<DeclRefExpr>(SubExpr)
15141 && "fixed to something other than a decl ref");
15142 assert(cast<DeclRefExpr>(SubExpr)->getQualifier()
15143 && "fixed to a member ref with no nested name qualifier");
15144
15145 // We have taken the address of a pointer to member
15146 // function. Perform the computation here so that we get the
15147 // appropriate pointer to member type.
15148 QualType ClassType
15149 = Context.getTypeDeclType(cast<RecordDecl>(Method->getDeclContext()));
15150 QualType MemPtrType
15151 = Context.getMemberPointerType(Fn->getType(), ClassType.getTypePtr());
15152 // Under the MS ABI, lock down the inheritance model now.
15153 if (Context.getTargetInfo().getCXXABI().isMicrosoft())
15154 (void)isCompleteType(UnOp->getOperatorLoc(), MemPtrType);
15155
15156 return UnaryOperator::Create(
15157 Context, SubExpr, UO_AddrOf, MemPtrType, VK_PRValue, OK_Ordinary,
15158 UnOp->getOperatorLoc(), false, CurFPFeatureOverrides());
15159 }
15160 }
15161 Expr *SubExpr = FixOverloadedFunctionReference(UnOp->getSubExpr(),
15162 Found, Fn);
15163 if (SubExpr == UnOp->getSubExpr())
15164 return UnOp;
15165
15166 return UnaryOperator::Create(
15167 Context, SubExpr, UO_AddrOf, Context.getPointerType(SubExpr->getType()),
15168 VK_PRValue, OK_Ordinary, UnOp->getOperatorLoc(), false,
15169 CurFPFeatureOverrides());
15170 }
15171
15172 if (UnresolvedLookupExpr *ULE = dyn_cast<UnresolvedLookupExpr>(E)) {
15173 // FIXME: avoid copy.
15174 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
15175 if (ULE->hasExplicitTemplateArgs()) {
15176 ULE->copyTemplateArgumentsInto(TemplateArgsBuffer);
15177 TemplateArgs = &TemplateArgsBuffer;
15178 }
15179
15180 DeclRefExpr *DRE =
15181 BuildDeclRefExpr(Fn, Fn->getType(), VK_LValue, ULE->getNameInfo(),
15182 ULE->getQualifierLoc(), Found.getDecl(),
15183 ULE->getTemplateKeywordLoc(), TemplateArgs);
15184 DRE->setHadMultipleCandidates(ULE->getNumDecls() > 1);
15185 return DRE;
15186 }
15187
15188 if (UnresolvedMemberExpr *MemExpr = dyn_cast<UnresolvedMemberExpr>(E)) {
15189 // FIXME: avoid copy.
15190 TemplateArgumentListInfo TemplateArgsBuffer, *TemplateArgs = nullptr;
15191 if (MemExpr->hasExplicitTemplateArgs()) {
15192 MemExpr->copyTemplateArgumentsInto(TemplateArgsBuffer);
15193 TemplateArgs = &TemplateArgsBuffer;
15194 }
15195
15196 Expr *Base;
15197
15198 // If we're filling in a static method where we used to have an
15199 // implicit member access, rewrite to a simple decl ref.
15200 if (MemExpr->isImplicitAccess()) {
15201 if (cast<CXXMethodDecl>(Fn)->isStatic()) {
15202 DeclRefExpr *DRE = BuildDeclRefExpr(
15203 Fn, Fn->getType(), VK_LValue, MemExpr->getNameInfo(),
15204 MemExpr->getQualifierLoc(), Found.getDecl(),
15205 MemExpr->getTemplateKeywordLoc(), TemplateArgs);
15206 DRE->setHadMultipleCandidates(MemExpr->getNumDecls() > 1);
15207 return DRE;
15208 } else {
15209 SourceLocation Loc = MemExpr->getMemberLoc();
15210 if (MemExpr->getQualifier())
15211 Loc = MemExpr->getQualifierLoc().getBeginLoc();
15212 Base =
15213 BuildCXXThisExpr(Loc, MemExpr->getBaseType(), /*IsImplicit=*/true);
15214 }
15215 } else
15216 Base = MemExpr->getBase();
15217
15218 ExprValueKind valueKind;
15219 QualType type;
15220 if (cast<CXXMethodDecl>(Fn)->isStatic()) {
15221 valueKind = VK_LValue;
15222 type = Fn->getType();
15223 } else {
15224 valueKind = VK_PRValue;
15225 type = Context.BoundMemberTy;
15226 }
15227
15228 return BuildMemberExpr(
15229 Base, MemExpr->isArrow(), MemExpr->getOperatorLoc(),
15230 MemExpr->getQualifierLoc(), MemExpr->getTemplateKeywordLoc(), Fn, Found,
15231 /*HadMultipleCandidates=*/true, MemExpr->getMemberNameInfo(),
15232 type, valueKind, OK_Ordinary, TemplateArgs);
15233 }
15234
15235 llvm_unreachable("Invalid reference to overloaded function");
15236 }
15237
FixOverloadedFunctionReference(ExprResult E,DeclAccessPair Found,FunctionDecl * Fn)15238 ExprResult Sema::FixOverloadedFunctionReference(ExprResult E,
15239 DeclAccessPair Found,
15240 FunctionDecl *Fn) {
15241 return FixOverloadedFunctionReference(E.get(), Found, Fn);
15242 }
15243